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U. S. DEPARTMENT OF LABOR
JAMES J. DAVIS, Secretary
BUREAU OF LABOR STATISTICS
ETHELBERT STEWART, Commissioner
BULLETIN OF THE UNITED STATES { . . . .
BUREAU OF LABOR STATISTICS J
SAFETY
CODE
ACQ
NO* 4 0 3
SERIES
SAFETY CODE FOR MECHANICAL
POWER-TRANSMISSION APPARATUS
f ir s t r e v is io n
RULES FOR GUARDING PRIME MOVERS, INTER
MEDIATE EQUIPMENT, AND DRIVEN MACHINES
SPONSOR ORGANIZATIONS
NATIONAL BUREAU OF CASUALTY AND SURETY UNDERWRITERS
INTERNATIONAL ASSOCIATION OF INDUSTRIAL ACCIDENT BOARDS AND COMMISSIONS
THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS
AMERICAN STANDARD
Approved November 11,1926
American Engineering Standards Committee
JUNE, 1928
UNITED STATES
GOVERNMENT PRINTING OFFICE
WASHINGTON
1928
SECTIONAL COMMITTEE WHICH DEVELOPED THE SAFETY CODE
FOR MECHANICAL POWER-TRANSMISSION APPARATUS
C arl B. Atjel, Chairman
C. Ainsworth, director Bureau of Industrial Standards, Department of Labor
and Industry, Harrisburg, Pa., representing International Association of Indus
trial Accident Boards and Commissions.
Carl B. Auel, manager Employees’ Service Departments, Westinghouse
Electric & Manufacturing Co., East Pittsburgh, Pa., representing the American
Society of Mechanical Engineers.
Frank M. Bullen, assistant underwriter United States Casualty Co., 80
Maiden Lane, New York, N. Y., representing the National Bureau of Casualty
and Surety underwriters.
Lucian W. Chaney, Bureau of Labor Statistics, United States Department
of Labor, Washington, D. C., representing the International Association of
Industrial Accident Boards and Commissions.
L. A. DeBlois, director Safety Engineering Division, National Bureau of
Casualty and Surety Underwriters, 120 West Forty-second Street, New York,
N. Y., representing National Bureau of Casualty and Surety Underwriters.
Paul Donley, 719 Fifteenth Street SE., Washington, D. C., representing the
International Association of Machinists.
L. L. Hall, secretary Rating Department, National Council on Compensation
Insurance, 151 Fifth Avenue, New York, N. Y., representing National Council
on Compensation Insurance.
Francis A. Hobart, 27 Morton Avenue, Newport, R. I., representing the
International Association of Machinists.
Holger Jensen, manager Engineering Department, Maryland Casualty Co.,
Baltimore, Md., representing the National Bureau of Casualty and Surety
Underwriters.
Arthur C. Jewitt, director College of Industries, Carnegie Institute of Tech
nology, Pittsburgh, Pa., representing the American Society of Mechanical
Engineers.
Roland H. Leveridge, deceased.
M. G. Lloyd, Bureau of Standards, Washington, D. C. representing Bureau
of Standards.
Robert M. Keown, chief engineer Industrial Commission, State Capitol,
Madison, Wis., representing the International Association of Industrial Accident
Boards and Commissions.
John P. Meade, director Division of Industrial Safety, Department of Labor
and Industries, State House, Boston, Mass., representing the International
Association of Industrial Accident Boards and Commissions.
Frank L. Morse, president Morse Chain Co., Ithaca, N. Y., representing
the American Society of Mechanical Engineers.
George M. Naylor, president the Fairbanks Co., 393 Lafayette Street, New
York, N. Y., representing the American Society of Mechanical Engineers.
Walter S. Paine, research engineer Bureau of Inspection and Accident
Prevention, Aetna Life Insurance Co., 650 Main Street, Hartford, Conn., repre
senting the National Bureau of Casualty and Surety Underwriters.
Bernhard C. Eiffel, rehabilitation assistant Bureau of Eehabilitation, the New
York State Department of Education, 108 Lexington Avenue, New York, N. Y.
Charles H. Savage, 235 Ninth Street, NE., Washington, D. C., representing
the International Association of Machinists.
H.
A. Schultz, assistant manager, Bureau of Safety, Sanitation, and Welfare,
United States Steel Corp., 71 Broadway, New York, N. Y., representing the
National Safety Council.
E. W. Sellew, Sellew & Towner, Central National Bank Building, Middletown,
Conn., representing the American Society of Mechanical Engineers.
in
114474
IV
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
O.
J. Smith (alternate for F. M. Bullen), United States Casualty Co., 80
Maiden Lane, New York, N. Y., representing National Bureau of Casualty
and Surety Underwriters.
John L. Thompson, superintendent Engineering and Inspection Division,
the Travelers Insurance Co., Hartford, Conn., representing the National Bureau
of Casualty and Surety Underwriters.
K. E. Turn (alternate for W. S. Paine), Bureau of Inspection and Accident
Prevention, Aetna Life Insurance Co., 650 Main Street, Hartford, Conn., repre
senting National Bureau of Casualty and Surety Underwriters.
G. N. VanDerhoef (alternate for D. C. Wright), consulting engineer Dodge
Mfg. Co., 29 West Broadway, New York, N. Y., representing the American
Society of Mechanical Engineers.
H. G. Wiberg, chief engineer and underwriter Lumber Mutual Casualty Insur
ance Co., 41 East Forty-second Street, New York, N. Y., representing National
Association of Mutual Casualty Companies.
John Williams, director Industrial Relations the Yale & Towne Mfg. Co.,
Stamford, Conn., representing National Safety Council.
Donald C. Wright, industrial consulting engineer, 3425 Wenonah Avenue,
Berwyn, 111., representing the American Society of Mechanical Engineers.
CONTENTS
INTRODUCTION
Scope______________________________________________________________
Interpretations and exceptions___________________________ ___________
New and old installations___________________________________________
Mandatory and advisory requirements_______________________________
Definitions_____________________________________________ ______ _____
Page
1
1, 2
2
2
2, 3
Part I.— PRIME MOVERS
Section 10. Prime mover guards_____________________________________
Rule 100. Flywheels____________________________________________
Rule 101. Cranks and connecting rods___________________________
Rule 102. Tail rods or extension piston rods______________________
Rule 103. Governor balls_______________________________________
4
4
4
4
4
Part II.— MECHANICAL POWER-TRANSMISSION EQUIP
MENT
Section 20. Shafting________________________________________________
Rule 200. Installation__________________________________________
Rule 201. Guarding horizontal shafting__________________________
Rule 202. Guarding vertical and inclined shafting_________________
Rule 203. Projecting shaft ends_________________________________
Rule 204. Power-transmission apparatus located in basements_____
Section 21. Pulleys_______________________________________________ 4
Rule 210. Guarding____________________________________________
Rule 211. Location of pulleys___________________________________
Rule 212. Broken pulleys_______________________________________
Rule 213. Pulley speeds_________________________________________
Rule 214. Belt guides___________________________________________
Rule 215. Composition and wood pulleys_________________________
Rule 216. Pulleys exposed to corrosion___________________________
Rule 217. Pulleys out of service_________________________________
Section 22. Belt, rope, and chain drives______________________________
Rule 220. Horizontal belts and ropes____________________________
Rule 221. Vertical and inclined belts_____________________________
Rule 222. Vertical belts_________________________________________
Rule 223. Cone pulley belts_____________________________________
Rule 224. Belt tighteners_______________________________________
Section 23. Gears, sprockets, and chains_____________________________
Rule 230. Gears________________________________________________
Rule 231. Sprockets and chains__________________________________
Rule 232. Openings for oiling___________________________________
Section 24. Friction drives__________________________________________
Rule 240. Guarding____________________________________________
Section 25. Keys, set screws, and other projections____________________
Rule 250. Elimination or guarding_______________________________
Section 26. Collars and couplings____________________________________
Rule 260. Collars_______________________________________________
Rule 261. Couplings___________________________________________
Section 27. Bearings and facilities for oiling___________________________
Rule 270. Bearings_____________________________________________
Rule 271. Ladders______________________________________________
Rule 272. Oilers’ runways and platforms................ ....... ......................
v
5-7
5
5
5
5
5-7
7
7
7
7
7
7
7
7
8, 9
8
8, 9
9
9
9
9, 10
9
10
10
10
10
10
10
10
10
10
13
13
13
13
VI
CONTENTS
Part III.—STARTING AND STOPPING DEVICES
Page
14
Section 30. Clutches, cut-off couplings, and clutch pulleys______________
Rule 300. Guarding____________________________________________
14
Section 31. Belt shifters, clutches, shippers, poles, perches, and fasteners. 14-16
Rule 310. Belt shifters_________________________________________
14
Rule 311. Belt shippers and shipper poles________________________
14
Rule 312. Belt perches__________________________________________
16
Rule 313. Belt fasteners________________________________________
16
Part IV.— GUARD STANDARDS
Section 40. Standard guards— General requirements___________________
Rule 400. Materials____________________________________________
Rule 401. Design of guards_____________________________________
Rule 402. Methods of manufacture______________________________
Section 41. Disk, shield, and U-guards________________________________
Rule 410. Disk guards__________________________________________
Rule 411. Shield guards_________________________________________
Rule 412. U-guards____________________________________________
Section 42. Approved materials______________________________________
Rule 420, Minimum requirements_______________________________
Rule 421. Wood guards_________________________________________
Rule 422. Guards for horizontal overhead belts___________________
Rule 423. Guards for horizontal overhead rope and chain drives__
Rule 424. Guard rails and toe boards____________________________
17
17
17
17
17, 18
17, 18
18
18
18-22
18, 19
19
19-22
22
22-24
Part V.— OPERATING RULES
Section 50. Care of equipment______________________________________ 25, 26
Rule 500. General______________________________________________
25
Rule 501. Shafting_____________________________________________
25
Rule 502. Bearings_____________________________________________
25
Rule 503. Hangers_____________________________________________
25
Rule 504. Pulleys______________________________________________
25
Rule 505. Care of belts_________________________________________ 25, 26
Rule 506. Belts on overhead pulleys_____________________________
26
Rule 507. Lubrication__________________________________________
26
Part VI.— DISCUSSION
Broken pulleys_____________________________________________________ ___ 27
Belt tighteners_____________________________________________________ ___ 27
Power control______________________________________________________ ___ 27
Power-transmission equipment----------------------------------------------------------- ----- 27
Hand-operated gears------------------------------------------------------------------------ ----- 27
Horizontal overhead belts----------------------------------------------------------------------- 28
Part VII.— REFERENCES
List of codes approved and published-------------------------------------------------List of codes in process of development_______________________________
29
29
BULLETIN OF THE
U. S. BUREAU OF LABOR STATISTICS
N o . 463
WASHINGTON
jo n e
. m m
SAFETY CODE FOR MECHANICAL POWER-TRANSMISSION APPARATUS
INTRODUCTION
SCOPE
This code applies to all moving parts of equipment used in the
mechanical transmission of power, including prime movers, inter
mediate equipment, and driven machines, excluding point of oper
ation.
The safeguarding of all connecting rods, cranks, flywheels, shafting,
spindles, pulleys, belts, link belts, chains, ropes and rope drives,
gears, sprockets, friction drives, cams, couplings, clutches, counter
weights, revolving or reciprocating parts, up to but not including
point of operation, also all bolts, keys, set screws, oil cups, or similar
projections are included and shall be in accordance with the pro
visions of the Mechanical Power-Transmission Apparatus Code.
N ote.— For exemptions see section on 11Interpretations and exceptions.”
INTERPRETATIONS AND EXCEPTIONS
The purpose of this code is to provide reasonable safety for life,
limb, and health. It is intended to serve as a guide to State ana
municipal authorities and may be adopted by them in whole or
in part. This safety code is also in a form to be adopted by indus
trial concerns.
The code should be liberally construed and applied by enforcing
authorities to secure these results; and, in case 01 practical difficulty
or unnecessary hardship, exceptions from the literal requirements
may be granted as long as equivalent protection is secured. Where
specific devices or methods are mentioned in this code, other devices
or methods which will secure equally good results may be used,
subject to the approval of the enforcing authority.
Flat belts 1 inch or less in width and round belts Yi inch or less
in diameter running at any speed and flat belts in association with
flat or crowned pulleys when 2 inches or less in width which are
free from metal lacings or fasteners and running not more than
250 feet per minute are exempted. This exemption does not include
spoke or other hazards of pulleys which shall be guarded.
Vertical and inclined belts (rules 221 and 222) if not more than
2
inches wide and running at a speed of less than 1,000 feet per
minute and if free from metal lacings or fastenings may be guarded
with a “ nip-point belt and pulley guard.” (See “ Definitions” — Nip
point belt and pulley guard.)
X
2
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
For the textile industry, because of the presence of the excessive
deposits of lint, which constitutes a serious fire hazard, the sides
and face sections only of nip-point belt and pulley guards will be
required, provided the guard shall extend at least 6 inches beyond
the rim of the pulley on the inrunning and offrunning sides 01 the
belt and at least 2 inches away from the rim and face of the pulley
in all other directions.
These regulations cover the principal features with which powertransmission safeguards shall comply. The mere technical fulfill
ment of these requirements does not assure the approval of the
guard if examination shows lack of practicability and/or durability.
The supervising authority may require guards not called for in
these standards, if, in the opinion of such authority, a sufficient
hazard exists to warrant such action.
NEW AND OLD INSTALLATIONS
After the date on which this code becomes effective all new con
struction and installations shall conform to its rules. Equipment
installed prior to that date need not, however, be modified to con
form to its rules unless definite provision is made in the enacting law.
MANDATORY AND ADVISORY REQUIREMENTS
The word “ shall,” where used, is to be understood as mandatory
and the word “ should” as advisory.
DEFINITIONS
Belt pole.— A “ belt pole,” sometimes called a “ belt shipper” or
“ shipper pole,” is a device used in shifting belts on and off pulleys
on line or countershaft where there are no loose pulleys.
Belt shifter.— A belt shifter is a device for mechanically shifting
belts from tight to loose pulleys or vice versa, or for shifting belts on
cones of speed pulleys.
Exposed to contact.— The term “ exposed to contact” shall be inter
preted as meaning that the location of an object is such that a person
is liable to come mto contact with it and be injured.
Flywheels.— The term “ flywheel” is to include flywheels, balance
1 1
1 11 ys mounted and revolving on crank shaft of engine
Gears.— A set or train of gears comprises two or more intermeshing
gears.
Maintenance runway.— “ Runway” shall mean any permanent
runway or platform used for oiling, maintenance, running adjustment
or repair work, but not for passageway.
Nip point belt and pulley guard.— A “ nip point belt and pulley
guard” is a device which mcloses the pulley and is provided with
rounded or rolled edge slots through which the belt passes. (See
“ Interpretations and exceptions” for textile industry.)
Point of operation.— The term “ point of operation” shall be under
stood to mean that point at which cutting, shaping, or forming is
accomplished upon the stock and shall include such other points as
may offer a hazard to the operator in inserting or manipulating the
stock in the operation of the machine.
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
3
Prime movers.— The term “ prime movers” as used in this code is
to include steam, gas, oil, ana air engines, motors, steam, and hy
draulic turbines.
Securely fastened.— The term “ securely fastened” shall mean that
the safety device or object referred to shall be so secured in place that
it can not be moved under normal or reasonably foreseen conditions
or circumstances.
Sheaves.— Sheaves shall be considered as grooved pulleys and shall
be so classified unless used as flywheels.
Sprockets.— A set of sprockets comprises two or more sprockets
carrying one or more chains.
87438°—H. Doc. 159, 70-1------ 2
PART I.— PRIME MOVERS
Section 10.—PRIME-MOVER GUARDS
Rule 100. Flywheels.
Flywheels located so that any part is 6 feet or less above floor
or platform shall be guarded in one of the following ways:
(а) With an inclosure of sheet, perforated, or expanded metal or
woven wire. For standards see Part IV, sections 40 and 41.
(б) With guard rails placed not less than 15 inches nor more than
20 inches from rim. When flywheel extends into pit or is within
12 inches of floor, a standard toe board shall also be provided. For
standards see Part IV, rule 424.
(c) When the upper rim of flywheel protrudes through a working
floor, it shall be entirely inclosed or surrounded by a guard rail and
toe board.
(d) For flywheels with smooth rims 5 feet or less in diameter, where
the preceding methods can not be applied, the following may be used:
A disk attached to the flywheel in such manner as to cover the spokes
of the wheel on the exposed side and present a smooth surface and
edge, at the same time providing means for periodic inspection. An
open space, not exceeding 4 inches in width, may be left between
the outside edge of the disk and the rim of the wheel, if desired, to
facilitate turning the wheel over. Where a disk is used the keys or
other dangerous projections not covered by disk shall be cut off or
covered. See standard for disk guard Part IV, section 41.
N ote.— This does not apply to flywheels with solid web centers.
(e) Adjustable guard to be used for starting engine or for running
adjustment may be provided at the flywheel of gas or oil engines.
A slot opening for jack bar will be permitted.
Rule 101.— Cranks and connecting rods.
Cranks and connecting rods, when exposed to contact, shall be
guarded in accordance with Part IV, sections 40 and 41, or by a
guard rail as described in Part IV, rule 424.
Rule 102.— Tail rods or extension piston rods.
Tail rods or extension piston rods shall be guarded in accordance
with Part IV, sections 40 and 42, or by a guard rail on sides and end,
with a clearance of not less than 15 inches when rod is fully extended.
Rule 103.— Governor balls.
Governor balls 6 feet or less from the floor or other working level,
when exposed to contact, shall be provided with an inclosure extend
ing to the top of the governor balls when at their highest position.
The material used in the construction of this inclosure shall conform
to Part IV,.sections 40 and 42.
4
PART II.— MECHANICAL POWER-TRANSMISSION
EQUIPMENT
Section 20.— SHAFTING
Buie 200. Installation.
(а) Each continuous line of shafting shall be secured in position
against excessive endwise movement.
(б) Inclined and vertical shafts, particularly inclined idler shafts,
shall be securely held in position against endwise thrust.
Rule 201. Guarding horizontal shafting.
(а) All exposed parts of horizontal shafting 6 feet or less from
floor working platform, excepting runways used exclusively for oiling,
or running adjustments, shall be protected by a stationary casing
inclosing shafting completely or by a trough inclosing sides and top
or sides and bottom of shafting as location requires.
(б) Wherever shafting extends over a driveway it should be pro
tected as stated above unless it is located 15 feet or more above
driveway.
(c) Shafting under bench machines shall be inclosed by a stationary
casing, or by a trough at sides and top or sides and bottom, as loca
tion requires. The sides of the trough shall come within at least
6 inches of the underside of table, or if shafting is located near floor
within 6 inches of floor. In every case the sides of trough shall
extend at least 2 inches below or above the shafting as the case
may be.
N ote.— For requirements regarding materials and construction see Part IV,
sections 40 and 42.
Rule 202. Guarding vertical and inclined shafting.
Vertical and inclined shafting 6 feet or less from floor or working
platform, excepting maintenance runways, shall be inclosed with a
stationary casing in accordance with requirements of Part IV,
sections 40 and 42.
Rule 203. Projecting shaft ends.
(а) Projecting shaft ends shall present a smooth edge and end and
shall not project more than one-half the diameter of the shaft unless
guarded by nonrotating caps or safety sleeves.
(б) Unused keyways shall be filled up or covered.
Rule 204. Power-transmission apparatus located in basements.
All mechanical power-transmission apparatus located in basements,
towers, and rooms used exclusively for power transmission equip
ment shall be guarded in accordance with these standards, except
that the requirements for safeguarding belts, pulleys, and shafting
may be waived when the following conditions are met:
1. The basement, tower, or room occupied by transmission equipment shall
be locked against unauthorized entrance.
2. The vertical clearance in passageways between the floor and power-transmission beams, ceiling or any other objects, should not be less than 5 feet 6 inches.
d
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
Trough G uards
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S H A F TIN G LOCATED UNDER BENCH MACHINES
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
7
3. The intensity of illumination shall conform to the standard Code for Light
ing of Factories, Mills, and other Work Places.
4. The footing shall be dry, firm, and level.
5. The route followed by the oiler shall be protected in such manner as to
prevent accident.
N ote.— The exemption granted by this rule shall not apply to single isolated
hazards which can be guarded without hardship in the usual prescribed manner.
Section 21.—PULLEYS
Rule 210. Guarding.
Pulleys any parts of which are 6 feet or less from the floor or work
ing platform shall be guarded in accordance with the standards
specified under Part IV, sections 40 and 42. Pulleys serving as
balance wheels (e. g., punch presses) on which the point of contact
between belt and pulley is more than 6 feet from the floor or plat
form may be guarded with a disk covering the spokes. See Part IV,
section 41.
Rule 211. Location of pulleys.
(a) Unless the distance to the nearest fixed pulley, clutch, or
hanger exceeds the width of the belt used, a guide shall be provided
to prevent the belt from leaving the pulley on the side where insuffi
cient clearance exists.
(i) Where there are overhanging pulleys on line, jack, or counter
shafts with no bearing between the pulley and the outer end of the
shaft, a guide to prevent the belt from running off the pulley should
be provided.
(c)
For requirements for guarding pulleys located in basements,
towers, and rooms where no employees are regularly stationed, see
Part II, section 20, rule 204.
Rule 212. Broken pulleys.
Pulleys with cracks, or pieces broken out of rims shall not be used.
Rule 213. Pulley speeds.
Pulleys operating at rim speed in excess of 4,000 feet per minute
shall be especially designed for the purpose and carefully balanced
for the speed at which they are to operate.
Rule 214. Belt guides*
Belt guides should not be installed except as provided in rule 211
(a) and (&).
Rule 215. Composition and wood pulleys.
Composition or laminated wood pulleys shall not be installed where
they are continually subjected to the action of moisture.
Rule 216. Pulleys exposed to corrosion.
Pulleys used where conditions are such as to produce active
corrosion should be of corrosion resisting material.
Rule 217. Pulleys out of service.
Pullers permanently out of service should not be allowed to remain
on shafting which is in use.
8
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
Section 22.— BELT, ROPE, AND CHAIN DRIVES
Rule 220. Horizontal belts and ropes.
(а) Where both runs of horizontal belts are 6 feet or less from
the floor level, the guard shall extend to at least 15 inches above the
belt or to a standard height (see table following rule 420) except
that where both runs of a horizontal belt are 42 inches or less from the
floor, the belt shall be fully inclosed in accordance with Part IV,
sections 40 and 42.
N ote.—In power plants or power-development rooms a guard rail may be
used in lieu of the above.
(б) Overhead horizontal belts, with lower part 7 feet or less from the
floor or platform, shall be guarded on sides and bottom in accordance
with Part IV, section 42, rule 422.
(c) Horizontal overhead belts more than 7 feet above floor or
platform shall be guarded for their entire length under the following
conditions:
1. If located over passageways or work places and traveling 1,800 feet or more
per minute, and
2. If center to center distance between pulleys is 10 feet or more, and
3. If belt is 8 inches or more in width.
N ote.— For details of guard construction and for sizes of material see Part IV,
section 42, rule 422, and table following rule 423, also Discussion, Part VI.
For exception in case of flat belts 1 inch or less in width, or round
belts
inch or less in diameter, see “ Interpretations and exceptions.”
(d) Where the upper and lower runs of horizontal belts are so
located that passage of persons between them would be possible,
the passage shall be either—
1. Completely barred by a guard rail or other barrier in accordance
with Part IV, sections 40 and 42; or
2. Where passage is regarded as necessary there shall be a platform
over the lower run guarded on either side by a railing completely
filled in with wire mesh or other filler, or by a solid barrier. The
upper run shall be so guarded as to prevent contact therewith either
by the worker or by objects carried by him.
In power plants only the lower rim of the belt need be guarded.
(e) Overhead chain and link belt drives, where the chain exceeds
2 inches in width, are governed by the same rules as overhead hori
zontal belts and shall be guarded in the same manner as belts.
N ote.— All guards to be constructed in accordance with Part IV, section 42,
rule 423.
(/) American or continuous system rope drives so located that
the condition of the rope (particularly the splice) can not be con
stantly and conveniently observed shall be equipped with a “ telltale”
device (preferably electric-bell type) that will give warning when
rope begins to fray.
For guarding of overhead rope drives, see Part IV, section 42,
rule 423.
Rule 221. Vertical and inclined belts.
(a)
Vertical and inclined belts shall be inclosed by a guard con
forming to standards in Part IV, sections 40 and 42.
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
0
(b)
All guards for inclined belts shall be arranged in such a man
ner that a minimum clearance of 6 feet 6 inches is maintained between
belt and floor at any point outside of guard.
N ote.— For exceptions in the case of narrow belts and slow moving belts
see “ Interpretations and exceptions.”
Rule 222. Vertical belts.
Vertical belts running over a lower pulley more than 6 feet above
floor or platform shall be guarded at the bottom in the same manner
as horizontal overhead belts, if conditions are such as stated in
Rule 220 (c), 1 and 3.
Note.—For exceptions in the case of narrow belts and slow-moving belts
see “ Interpretations and exceptions.”
Rule 223. Cone-pulley belts.
The cone belt and pulley shall be equipped with a belt shifter
so constructed as to adequately guard the nip point of the belt and
pulley. If the frame of the belt shifter does not adequately guard
the nip point of the belt and pulley, the nip point shall be further
protected by means of a vertical guard placed in front of the pulley
and extending at least to the top of the largest step of the cone.
If the belt is of the endless type or laced with rawhide laces, and
a belt shifter is not desired, the belt will be considered guarded if the
nip point of the belt and pulley is protected by a nip point guard
located in front of the cone, extending at least to the top of the largest
step of the cone, and formed to show the contour of the cone in order
to give the nip point of the belt and pulley the maximum protection.
(See rule 313.)
If the cone is located less than 3 feet from the floor or working
platform, the cone pulley and belt shall be guarded to a height of 3
feet regardless of whether the belt is endless or laced with rawhide.
Rule 224. Belt tighteners.
(a) Suspended counterbalanced tighteners and all parts thereof
shall be of substantial construction and securely fastened; the bear
ings shall be securely 'capped. Means must be provided to prevent
tightener from falling in case the belt breaks.
N ote.— See Discussion, Part VI.
(b) Where suspended counterweights are used and not guarded
by location, they shall be so encased as to prevent accident.
Section 23.— GEARS, SPROCKETS, AND CHAINS
Rule 230. Gears.
Gears shall be guarded in accordance with one of the following
specifications:
(a) A complete inclosure.
(b) A standard guard as described in section 42 at least 6 feet high extending
6 inches above the mesh point of the gears.
(c) By a band guard covering the face of gear and having flanges extended
inward beyond the root of the teeth on the exposed side or sides. Where any
portion of the train of gears guarded by a band guard is less than 6 feet from the
floor a disk guard or a complete inclosure to the height of 6 feet shall be required.
Note.— Rule does not apply to hand-operated gears used only to adjust machine
parts and which do not continue to move after hand power is removed. How
ever, the guarding of these gears is highly recommended. See part VI, par. 5.
10
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
Buie 231. Sprockets and chains.
All sprocket wheels and chains shall be inclosed unless more than
7 feet above the floor or platform.
N ote.— This does not apply to manually operated sprockets.
Rule 232. Openings for oiling.
When frequent oiling must be done, openings with hinged or
sliding self-closing covers shall be provided.
Section 24.—FRICTION DRIVES
Rule 240. Guarding.
(a) The driving point of all friction drives when exposed to con
tact shall be guarded.
(b) All arm or spoke friction drives and all web friction drives with
holes in the web shall be entirely inclosed.
(c) All projecting bolts on friction drives where exposed to con
tact shall be guarded.
Section 25.—KEYS, SET SCREWS, AND OTHER PROJECTIONS
Rule 250. Elimination or guarding.
All projecting keys, set screws and other projections in revolving
parts shall be removed or made flush or guarded by metal cover. This
does not apply to keys or set screws within gear or sprocket casings or
other inclosures, nor to keys, set screws or oil cups in hubs of pulleys
less than 20 inches in diameter where they are within the plane of the
rim of the pulley.
It is recommended, however, that no projecting set screws or oil
cups be used in any revolving pulley or part of machinery, even though
they are within the limits stated in the above paragraph.
Section 26.— COLLARS AND COUPLINGS
Rule 260. Collars.
All revolving collars, including split collars, shall be cylindrical,
and screws or bolts used in collars shall not project beyond the largest
periphery of the collar.
Rule 261. Couplings.
(a)
Shaft couplings shall be so constructed as to present no hazard
from bolts, nuts, set screws, or revolving surfaces.
Bolts, nuts, and set screws will, however, be permitted where they
are covered with safety sleeves or where they are used parallel with
the shafting and are countersunk or else do not extend beyond the
flange of the coupling.
N ote.— While the use of a rib or clamp type coupling is not recommended
they will be acceptable if the ends of the fastenings be well within the periphery
of the body of the coupling and the ends of all bolts are flush with or below the
crown of the nut. All outside surfaces are to be turned or ground and outside
edges carefully rounded.
(i) The shifting part of jaw clutches and the shifting or mechanism
part of friction clutch couplings should be attached to the driven
shafts i. e., the shaft that will be idle when clutch is disengaged.
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
S a f e t v Set S c r e w s
Countersunk Heads with SpecialWrenches
75prevent s e t screws fiom backingoffti hat
been -foundgoodpractice, toprickpunch threads after sere#
fjas been tightened, ft is afso we/f to spot shaft by means
o f drill or ordinary caseharefenecfset screw before insert"
ing get screw:
87438°— H. Doc. 159, 70-1------ 3
11
12
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
S h a f t C o u p l in g s
Split Coupling
.Solid Sleeve Coupling
■€
C/amp Cot/pfthgtyii&
3
-
Cdtnpress/on 7?pe-Coupf//ig
-fia
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“j" " t
B dl(foaJo&Nut* CMtntmr&aak.
Flonde* Project JSttyv..
BoHHe+d* &.tfu£o.
Flange Couplings
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
13
Section 27.— BEARINGS AND FACILITIES FOR OILING
Rule 270. Bearings.
(a) Self-lubricating bearings are recommended.
(b) All drip cups and pans shall be securely fastened.
Rule 271. Ladders.
Wherever portable ladders are used in oiling, repairing, or adjusting
power-transmission machinery, these ladders shall be equipped with
safety hooks or antislip device at bottom.
N o t e .—For
standard construction of ladders see “ Safety Code for Ladders.”
Rule 272. Oilers* runways and platforms
Shall conform to the “ Safety Code for Floor and Wall Openings,
Railings, and Toe Boards.”
PART III.— STARTING AND STOPPING DEVICES
Section 30.— CLUTCHES, CUT-OFF COUPLINGS, AND CLUTCH PULLEYS
Rule 300. Guarding.
(a)
Clutches, cut-off couplings, or clutch pulleys haying projecting
parts, where such clutches are located 7 feet or less above the floor or
working platform, shall be inclosed by a stationary guard constructed
in accordance with these standards (the U type guard is permissible,
see rule 412).
N ote 1.— Where clutches, cut-off couplings, or clutch pulleys are so situated
within a machine or otherwise guarded by location, the application of this rule
is within the discretion of the enforcing authority.
N ote 2.— In engine rooms a guard rail, preferably with toe board, will be per
mitted instead of the above, provided this room is occupied only by engine-room
attendants.
N ote 3.— The use of a bearing support immediately adjacent to a friction clutch
or cut-off coupling being recognized engineering practice, only self-lubricating
bearings requiring attention at infrequent intervals shall be used in such locations.
Section 31.—BELT SHIFTERS, CLUTCHES, SHIPPERS, POLES,
PERCHES, AND FASTENERS
Rule 310. Belt shifters.
(a) Tight and loose pulleys on all new installations made subse
quent to the date of the adoption of this code shall be equipped with
a permanent belt shifter provided with mechanical means to prevent
belt from creeping from loose to tight pulley.
N ote.— It is recommended that old installations be changed to conform to
this rule.
( b) Belt shifter and clutch handles shall be rounded and be located
as far as possible from danger of accidental contact, but within easy
reach of the operator. Wnere belt shifters are not directly located
over a machine or bench, the handles shall be cut off 6 feet 6 inches
above floor level.
(c) All belt and clutch shifters of the same type in each shop
should move in the same direction to stop machines, i. e., either all
right or all left.
N ote.— This does not apply to friction clutch on countershaft carrying two
clutch pulleys with open and crossed belts, respectively. In this case the snifter
handle has three positions and the machine is at a standstill when clutch handle
is in the neutral or center position.
Rule 311. Belt shippers and shipper poles.
The use of belt poles as substitutes for mechanical shifters is not
recommended. Where necessity compels their use they shall be of
sufficient size to enable workmen to grasp them securely. (A 2-inch
diameter or
bv 2-inch cross-section is suggested.) Poles shall
be smooth and preferably of straight grain hardwood, such as ash or
hickory. The edges of rectangular poles should be rounded. Poles
should extend from the top of the pulley to within about 40 inches
of floor or working platform.
14
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
3
=
1
The Right Way
J
The Wrong Woy
The Right Woy: Countershaft with spaces affowecfso
if belts slip off they cannot wedge andpuff the
Countershaft upon workmen.
The Wrong Ways Countershaft showing howbelts may
wedge when they siip offpu/feys /f insufficient
space is aiiowed.
METHODS FOR SPACING PULLEYS
For Horizontal Belts
TYPES OF SAFE BELT PERCHES
16
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
Rule 312. Belt perches.
Where loose pulleys or idlers are not practicable, belt perches in
form of brackets, rollers, etc., shall be used to keep idle belts away
from the shafts. Perches should be substantially made and so
designed that the shipping of belts to and from them can be safely
accomplished.
Simpte Type of Belt Hook ond Belt Guide
to prevent Belt from dropping between
Pulleys or onto Line Snaft
“O'* Must be more than width
o f widest belt.
“H*Belt Hanger to hoid idfe belt
Rule 313. Belt fasteners.
Belts which of necessity must be shifted by hand and belts within
6 feet of the floor or working platform which are not guarded in
accordance with the intent of this code shall not be fastened with
metal in any case nor with any other fastening which by construction
or wear will constitute an accident hazard.
PART IV.— GUARD STANDARDS
Section 40.— STANDARD GUARDS—GENERAL REQUIREMENTS
Rule 400. Materials.
(a) Standard conditions will be secured by the use of the following
materials: Expanded metal, perforated or solid sheet metal, or wire
mesh on a frame of angle iron or iron pipe securely fastened to floor
or to frame of machine. See section 42, rule 420.
(b) All metal should be free from burrs and sharp edges.
(c) Wire mesh should be of the type in which the wires are securely
fastened at every cross point either by welding, soldering, or galvan
izing, except in case of diamond or square wire mesh made of No. 14
gauge wire, %-inch mesh or heavier.
N ote.— For method of fastening diamond or square wire mesh made of crimped
wire into frames see rule 402 (3).
Rule 401. Design of guards.
(а) Where it is necessary to change belts, make adjustments, or
for the admission of oil or grease, guards should preferably be pro
vided with hinged sections or be made removable.
(б) Guards should be designed so as not to interfere with the usual
machine operations, but give the maximum protection to the operator.
Rule 402. Method of manufacture.
(а) Expanded metal, sheet or perforated metal, and wire mesh
shall be securely fastened to frame by one of the following methods:
(1) With rivets or bolts spaced not more than 5 inches center to center. In
case of expanded metal or wire mesh, metal strips or clips shall be used to form
a washer for rivets or bolts.
(2) By welding to frame every 4 inches.
3) By weaving through channel or angle frame, or if No. 14 gauge
inch
mesh or heavier is used by bending entirely around rod frames.
(4)
Where openings in pipe railing are to be filled in with expanded metal,
wire mesh, or sheet metal, the filler material shall be made into panels with rolled
edges or bound with v or u edging of No. 24 gauge or heavier sheet metal fastened
to the panels with bolts or rivets spaced not more than 5 inches center to center.
The bound panels shall be fastened to the railing by sheet-metal clips spaced not
more than 5 inches center to center.
N ote.— Diamond or square mesh made of crimped wire fastened into channels,
angle or round-iron frames, may also be used as a filler in guards.
Size of mesh shall correspond to table given under rule 420.
(б) Where the design of guards requires filler material of greater
area than 12 square feet, additional frame members shall be provided
to maintain panel area within this limit.
(c)
All joints of framework shall be made equivalent in strength
to the material of the frame.
Section 41.— DISK, SHIELD, AND "U ” GUARDS
Rule 410. Disk guards.
(a)
A disk guard shall consist of a sheet-metal disk not less than
No. 22 gauge fastened by U bolts or rivets to spokes of pulleys, fly
wheels or gears. Where possibility of contact with sharp edges of the
17
18
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
disk exists, the edge shall be rolled or wired. In all cases the nuts
shall be provided with lock nuts which shall be placed on the unex
posed side of the wheel.
Rule 411. Shield guards.
(a) A shield guard shall consist of a frame filled with wire mesh,
expanded, perforated, or solid sheet metal.
(b) If area of shield does not exceed 6 square feet the wire mesh
or expanded metal may be fastened in a framework of ^ -in ch solid
rod, % by % by ^-inch angle iron or metal construction of equivalent
strength.
Metal shields may have edges entirely rolled around a ^g-inch
solid iron rod.
N o t e .— All material of shield guard shall meet the requirements of section
42, rule 420.
Rule 412. U guards.
U guards shall be constructed of materials specified in table,
section 42, rule 420. Edges shall be smooth and if size of guard
requires, these edges shall be reinforced by rolling, wiring, or by
binding with angle or flat iron.
Section 42.— APPROVED MATERIALS
Rule 420. Minimum requirements.
The materials and dimensions specified in this rule shall apply
to all guards except horizontal overhead belts, rope, cable, or chain
guards more than 7 feet above floor, or platform. (For the latter
see table following rule 423.)
(a) Table of standard materials and dimensions
Material
Clearance from moving
parts at all points
/Under 4 inches..
\4 to 15 inches....
Expanded metal.......................... /Under 4 inches..
\4 to 15 inches— .
Perforated metal......................... /Under 4 inches..
\4 to 15 inches....
Sheet metal.................................. 'Under 4 inches..
4 to 15 inches...
Under 4 inches..
Wood or metal strip crossed.......
[4 to 15 inches....
Woven wire.................................
Wood or metal strip|not crossed.
[Under 4 inches..
[4 to 15 inches....
Standard rail............................... /Mimimum 15 inches.
\Maximum 20 inches..
or opening
allowable
Minimum
Minimum
height of
gauge (U. S. guard
standard) or floor orfrom
plat
thickness
form level
M inch...
2 inches..
y<i inch...
2 inches..
Yi inch...
2 inches.
No. 16..
No. 12..
No. 18..
No. 13..
No. 20..
No. 14..
No. 22..
No. 22.
/W ood % inch.
y2 inch...
\Metal No. 16..
/W ood % inch.
2 inches.
\Metal No. 16..
Yl inch w idth... /W ood % inch.
\Metal No. 16..
1 inch width___ /W ood H inch.
\Metal No. 16..
See standard for railings (rule 424)
N o t e .— For flat belts 1 inch or less in width and round belts
in diameter see “ Scope.”
Feet
inch or less
(6) Framework.
(1)
Minimum dimensions of materials for the framework of all guards except
as noted in paragraph 3 shall be angle iron 1 by 1 by
inch, metal pipe of
inch
inside diameter or metal construction of equivalent strength.
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
19
All guards shall be rigidly braced every 3 feet or fractional part of their height
to some fixed part of machinery or building.
(2) The framework for all guards fastened to floor or working platform and
without other support or bracing shall consist of
by
by J^-inch angle
iron, metal pipe of
inches inside diameter or metal construction of equivalent
strength. All rectangular guards shall have at least four upright frame members
each of which shall be carried to the floor and be securely fastened thereto.
Cylindrical guards shall have at least three supporting members carried
to floor.
(3) Guards 30 inches or less in height and with a total surface area not in
excess of 10 square feet may have a framework of % inch solid rod, M by
by
Ys inch angle or metal construction of equivalent strength. The filling material
shall correspond to the requirements of the table under rule 420.
N o t e .— This rule is made for the purpose of providing a standard for small
guards not subject to severe stress for use in locations where guards constructed
of framework as specified in the above standards would be cumbersome and
unnecessarily expensive.
(c)
The specifications given in (a) and (b) are the minimum
requirements; where guards are exposed to unusual wear or deteri
oration, heavier material should be used.
Rule 421. Wood guards.
(a) Wood guards may be used in the woodworking and chemical
industries, in industries where the presence of fumes or where manu
facturing conditions would cause the rapid deterioration of metal
guards; also in construction work and in locations outdoors where
extreme cold or extreme heat make metal guards and railings unde
sirable. In all other industries wood guards will not be allowed
except by special permission of the supervising authority.
N o t e .— A wood guard unless very carefully constructed is not substantial.
Wood guards are a decided fire hazard, especially when they become saturated
with oil and when they are located near flammable material.
(b) Material and construction.
(1) Wood shall be sound, tough, and free from any loose knots.
(2) Guards shall be made of planed lumber not less than 1 inch rough board
measure and edges and corners rounded off.
(3) Wood guards shall be securely fastened together with wood screws, hard
wood dowel pins, bolts, or rivets.
(4) While no definite dimensions are given under this heading for framework
or filler materials, wood guards shall be equal in strength and rigidity to metal
guards specified in rule 420 (a), (b), and (c).
(5) For construction of standard wood railing see section 42, rule 424.
Buie 422. Guards for horizontal overhead belts.
(a)
Guards for horizontal overhead belts shall run the entire
length of the belt and follow the line of the pulley to the ceiling or
be carried to the nearest wall, thus inclosing the belt effectively.
Where belts are so located as to make it impracticable to carry the
guard to wall or ceiling, construction or guard shall be such as to
inclose completely the top and bottom runs of belt and the face of
pulleys. See rule 220 (b) and (c).
(6) The guard and all its supporting members shall be securely
fastened to wall or ceiling by gimlet-point lag screws or through
bolts. In case of masonry construction, expansion bolts shall be
used. The use of bolts placed horizontally through floor beams or
ceiling rafters is recommended.
(c) Suitable reinforcement shall be provided for the ceiling rafters
or overhead floor beams, where such is necessary, to sustain safely
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
GUARD
CONSTRUCTION
Front
Side
GEAR GUARD WITH WIRE CLOTH FILLER
GEAR GUARD OF SHEET METAL
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
21
the weight and stress likely to be imposed by the guard. The interior
surface of all guards, by which is meant the surface of the guard
with which a belt will come in contact, shall be smooth ana free
from all projections of any character, except where construction
demands it; protruding shallow round-head rivets may be used.
Overhead belt guards shall be at least one-quarter wider than belt
which they protect, except that this clearance need not in any case
exceed 6 inches on each side. Overhead rope drive and block and
roller-chain-drive guards shall be not less than 6 inches wider than
the drive on each side.
GUARD
CO NSTRUCTION
/ SheetMetalMod4orHeavier
IROM PIPE GUARD WITH
W IRE CLOTH FILLER
PROTECTION O F
ROUGH E D G ES
TP*
PERFORATED OR
SHEET METAL BOLTED
DIRECTLY TO ANGLE
FLAT STRIP
RIVETED (OR BOLTED)
TO ANGLE TO
FA6TEN FILLER
WOVEN WIRE.
I* MESH %*R0tfND
FRAMES
Pipe-Instcfe eftam.
(m/h)
i
FLY
--V\-*\<?L
o*($?*.)7'-—- - >l\ ;//
\>J /
\ w '//
WHEEL GUARD
ardX (
)
ard
J Showing Standard
------- -
board
I . R a i l i n g andToeboard
In overhead silent chain-drive guards where the chain is held from
lateral displacement on the sprockets the side clearances required on
drives of 20-inch centers or under shall be not less than 34 inch from
the nearest moving chain part and on drives of over 20-inch centers
a minimum of 3^ inch from the nearest moving chain part.
(d)
The table following rule 423 gives sizes of materials to be used
and general construction of guards for belts 10 inches or more in
width. No material for overhead belt guards should be smaller
than that specified in this table for belts 10 to 14 inches wide, even if
the belt is less than 10 inches in width. However, No. 20 gauge
sheet metal may be used as a filler on guards for belts less than 10
inches wide. Expanded metal, because of the sharp edges, should
not be used as a filler in horizontal belt guards.
22
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS
{e) For clearance between guards and belts, ropes, or chains of
various center to center dimensions between the shafts see bottom
of table following rule 423.
Rule 423. Guards for horizontal overhead rope and chain drives.
Overhead-rope and chain-drive guard construction shall conform
to the rules for overhead-belt guard construction of similar width,
except that the filler material shall be of the solid type as shown in
the table unless the fire hazard demands the use of open construction.
A side guard member of the same solid filling material should be
carried up in a vertical postion 2 inches above the level of the lower
run of the rope or chain drive and 2 inches within the periphery of
the pulleys which the guard incloses, thus forming a trough. These
side filler members should be reinforced on the edges with I K by
M
flat steel, riveted to the filling material at not greater than
8-inch centers; the reinforcing strip should be fastened or bolted to
all guard supporting members with at least one ^-inch rivet or bolt
at each intersection, and the ends should be secured to the ceiling
with lag screws or bolts. The filling material shall be fastened to the
framework of the guard and the filler supports by TV inch rivets
spaced on 4-inch centers. The width of the multiple drive shall be
determined by measuring the distance from the outside of the first
to the outside of the last rope or chain in the group accommodated
by the pulley.
Rule 424. Guard rails and toe boards.
(a) Guard rail shall be 42 inches in height, with mid rail between
top rail and floor.
(b) Posts shall be not more than 8 feet apart; they are to be perma
nent and substantial, smooth, and free from protruding nails, bolts,
and splinters. If made of pipe, it shall be 134 inches inside diameter,
or larger. If made of metal shapes or bars their section shall be
equal in strength to that of 13^ by V/2 by ^ -in ch angle iron. If
made of wood, the posts shall be 2 by 4 inches or larger. The upper
rail shall be 2 by 4 inches, or two 1 by 4 strips, one at the top and one
at the side of posts. The mid rail may be 1 by 4 inches or more. The
rails (metal shapes, metal bars, or wood), should be on that side of
the posts which gives the best protection and support. Where
panels are fitted with expanded metal or wire mesh as noted in table,
420 (a), the middle rails may be omitted.
(c) Toe boards shall be 4 inches or more in height, of wood, metal,
or of metal grill not exceeding 1 inch mesh. Toe boards at flywheel
pits should preferably be placed as close to edge of the pit as possible.
,
,
Horizontal overhead belts ropes and chains 7 feet or more above floor or 'platform
id t h .
Material.
Over 10" to 14" inclusive.
2" x 2 " x
No. 20 A. W. G ............................
2" x A " flat iron ....................
No. 18 A. W. G ...
2" x ^ " flatiron..
2" x H "................
iy2"x
.....................
2 "x*"........................
' .......
2"x&"......... .
3" x 3 " x
..................
2"x&"..................
No. 18 A. W . G ..............
2H " x 2H " x
angle..
Angle iron.
Flatiron.
Solid sheet metal.
Flat and angle.
Flatiron.
Filler supports to framework...................................... . (2)*"......................
Filler flats to supports (belt guards)........................... Q)A"....................
..............
::::::::<2)H"
Filler to frame ana supports (rope and chain guards).. A " rivets spaced................
8 " centers on sides and 4 " centers on bottom.
Guard supports to framework.................
(2)^"....:...............
(2)*"............................. (2)H"....................
Guard and supports to overhead ceiling.
M " x 3M" lag screws or H " bolts.
x 4" lag screws or
bolts.. % " x 6" lag screws or H " bolts..
Rivets.
Flush rivets.
Rivets or bolts.
Lag screws or bolts.
DETAILS— SPACING, ETC.
Width of guards..........................................
Spacing between filler supports.................
Spacing between filler flats (belt guards).
Spacing between guard supports..............
One-quarter wider than belt, rope, or chain drive.
20" C. toC
16" C. to C .
2" apart...
2)4" apart..
36" C .toC .
36" C. to C .
16" C .to C .
3" apart___
36" O. to C .
No. 20 A. W. G............................. No. 18 A. W . G ...
No. 12 A .W . G............................. No. 10 A. W . G ...
No. 18 A. W . G.
No. 8 A. W. G ..
POWER-TRANSMISSION
FASTENINGS.
FOR
1H " x 1H" x U ” .....................
Over 24".
CODE
Framework..................................
Filler (belt guards)......................
Filler and vertical side member.
Filler supports.............................
Guard supports...........................
Over 14" to 24" inclusive.
SAFETY
W
Guard.
OTHER BELT GUARD FILLING PERMITTED.
c LEARANCE
FROM OUTSIDE OF BELT, ROPE, OR CHAIN DRIVE TO GUAR]0.
Distance center to center of shafts................................ Up to 15' inclusive........................ Over 15' to 25' inclusive.............
Clearance from belt, rope, or chain to guard...............
10"................................................
Solid or perforated.
Over 25' to 40' inclusive.............
15"................................................
Over 40'.
20".
APPARATUS,
Sheet metal fastened as in rope and chain guards..
Woven wire, 2" mesh...............................................
to
CO
PART V,— OPERATING RULES.
Section 50.—CARE OF EQUIPMENT.
Buie 500. General.
All power-transmission equipment shall be inspected at intervals
not exceeding 60 days and be kept in good working condition at all
times.
Buie 501. Shafting.
(a) Shafting shall be kept in alignment, free from rust, and ex
cess oil or grease.
(&) Where explosives, explosive dusts, flammable vapors, or flam
mable liquids exist, the hazard of static sparks from shafting shall
be carefully considered.
N o te .— Static electricity may be removed by means of a spring copper brush
in contact with the shafting. This brush must be well grounded through No.
12 insulated copper wire. Other effective methods may be used.
Buie 502. Bearings.
Bearings shall be kept in alignment and properly adjusted.
Buie 503. Hangers.
Hangers shall be inspected to make certain that all supporting
bolts and screws are tight and that supports of hanger boxes are
adjusted properly.
Buie 504. Pulleys.
(a) Pulleys shall be kept in proper alignment to prevent belts
from running off.
(b) Both driving and driven pulleys carrying a nonshifting belt
should have crowned faces.
(<?) Cast-iron pulleys should be tested frequently with a hammer
to disclose cracks in rim or spokes. It should be borne in mind
that the sound is usually much different i f the belt is or is not
on the pulley.
(d)
Split pulleys should be inspected to ascertain i f all bolts
holding together the sections o f the pulley are tight.
Buie 505. Care of belts.
(a) Quarter-twist belts when installed without an idler can be
used on drives running in one direction only. They will run off a
pulley when direction o f motion is reversed.
(b) Inspection shall be made o f belts, lacings, and fasteners and
such equipment kept in good repair.
(c) Where possible, dressing should not be applied when belt or
rope is in motion; but, if this is necessary, it should be applied where
belts or rope leave pulley, not where they approach. The same
precautions apply to lubricating chains.
(d) The hazard o f static electricity from belts shall be carefully
considered where explosives, explosive dusts, flammable vapors, or
flammable liquids exist*
25
26
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS.
N o te .—Static electricity may be removed from belts by means of metallic
flexible-tooth combs the same width as the belts. One comb should be placed
within 10 inches of the line of contact where the belt leaves each pulley or
flywheel. These combs should be in contact with and placed transversely to
the belt and also be well grounded with No. 12 insulated copper wire. The
teeth of the comb should point in the direction of the belt motion. Other
effective methods may be used.
Rule 506. Belts on overhead pulleys.
A belt pole should be used to throw off or put on belts.
In unshipping a belt it should always be thrown off the driving
pulley, not the driven.
It is advisable to have one experienced man to take care o f over
head belts and put them on and take them off pulleys.
Belts should not be allowed to ride on shafting but should be
held from same either by loop or belt perch. (See rule 312.)
Buie 507. Lubrication.
The regular oilers shall wear tight-fitting clothing and should
use cans with long spouts to keep their hands out o f danger.
Machinery shall be oiled when not in motion, wherever possible.
PART VI.— DISCUSSION.
1. Broken pulleys.—Under section 21, rule 212 states that pulleys
with small pieces broken out o f rim shall not be used. The rough
edges formed by pieces broken out o f pulley rim offer a decided acci
dent hazard in case anyone should come in contact with the rough
edge o f the pulley rim. Considerable unnecessary wear on the belt
is also caused.
2. Belt tighteners.—Under section 22, rule 223 states that belt
tighteners o f the suspended type shall be arranged in such a way as
to prevent falling on any person below, should the belt break: or
throw tightener. This can be accomplished by securely fastening
cables or chains o f sufficient strength to the tightener and to the roof,
or some substantial object above, to prevent it from falling1, far
enough to strike a person.
3. Power control.—Among the methods used for power control
may be mentioned motor switches, friction clutches, belt shifters, and
engine stops. The means for controlling power should be positive
and should be so arranged as to permit o f operation from a point
not more than 100 feet from any machine driven from the source of
power in question. I f the stations can. be arranged to be within 50
feet o f any machine, it is highly advisable. There will be cases, as
for example in the steel industry, where a greater distance from the
machine becomes necessary.
It is advisable to mark the stop station with a mark easily dis
tinguishable—green bands on posts and green circles on walls are
recommended, together with a sign “ Stop station ” or “ Emergency
stop.” A light o f characteristic color should be added in shops where
night work is carried on.
A ll electrical safety devices should operate by the opening o f a
normally closed circuit. Any failure o f the current or device will
thus be indicated by the stopping of the prime mover. It is ad
visable to test such devices daily by shutting off the power at noon
or night by such means.
4. Power-transmission equipment.—Rule 204 states certain condi
tions under which the guarding of power-transmission equipment
may be modified. This rule was inserted as frequently in paper or
saw nylls, woodworking plants, etc., transmission equipment is lo
cated in basements, lofts, or transmission towers not used for any
other purpose, and it would be a hardship to require the complete
guarding of this apparatus.
5. Hand-operated gears.—The note under rule 230 states that
hand-operated gears need not be equipped with guards. Quite fre
quently, however, such gears are operated by a short lever or crank,
and when the operator braces himself against the frame of the ma
chine he is likely to come in contact with the gears. It is always
good practice to look into this matter carefully, and wherever there
is the slightest chance of injury it is well to provide guards.
27
28
SAFETY CODE FOR POWER-TRANSMISSION APPARATUS.
6.
Horizontal overhead belts.—Rule 220 (c) covers guarding o f
horizontal overhead belts more than 7 feet above floor or platform.
It is a difficult proposition to decide which overhead belts need
guarding and which can be left exposed. These belts, under certain
operating conditions, offer a decided accident hazard in case they
break. Any belt transmitting power is subjected to a certain stress
which increases with the load and the speed. In case this belt
breaks this force is reduced somewhat, due to the fact that the driv
ing power is eliminated. The belt is impelled only by its momentum,
but this is usually sufficient to give it a decided whipping force
strong enough to cause considerable damage. This question of
overhead belts located more than 7 feet above floor or working plat
form is well worth investigating as the cost o f one serious accident
might suffice to pay for quite a number o f guards,
PART VII.— REFERENCES
The Safety Codes printed in the list below are those dealing with
subjects other than Mechanical Power-Transmission Apparatus but
related in some way to this Code. These Codes, when completed
and approved will be known as “ American Standard” or “ Tentative
American Standard” Codes and may be obtained from the American
Engineering Standards Committee, 29 West Thirty-ninth Street,
New York.
APPROVED AND PUBLISHED
Abrasive Wheels, Safety Code for the Use, Care and Protection of.
Aeronautics, Safety Code for.
Automobile Brakes and Brake Testing, Safety Code for.
Building Exits Code.
Electrical Equipment in Coal Mines, Safety Rules for Installing and Using.
Electrical Code, National.
Electrical Safety Code, National.
Elevators and Escalators, Safety Code for.
Explosives, Permissible, Specifications for the Testing and Use of.
Forging and Hot Metal Stamping, Safety Code for.
Foundries, Safety Code for the Protection of Industrial Workers in.
Gas Safety Code.
Heads and Eyes of Industrial Workers, Safety Code for the Protection of.
Ladders, Safety Code for. *
Laundry Machinery and Operations, Safety Code for.
Lighting Factories, Mills, and Other Work Places, Code of.
Lighting of School Buildings, Code for.
Logging and Sawmill Machinery, Safety Code for.
Paper and Pulp Mills, Safety Code for.
Power presses and Foot and Hand Presses, Safety Code for.
Woodworking Plants, Safety Code for.
CODES IN PROCESS OF DEVELOPMENT
Compressed Air Machinery, Safety Code for.
Construction Work, Safety Code for.
Conveyors and Conveying Machinery, Safety Code for.
Cranes, Derricks, and Hoists, Safety Code for.
Electrical Fire and Safety Code.
Exhaust Systems, Safety Code for.
Explosives, Safety Code for.
Floor and Wall Openings, Railings, and Toe Boards, Safety Code for.
Lamps, Electric Mine, Permissible Portable.
Lightning, Code on Protection Against.
Locomotives, Storage Battery, for Use in Gaseous Mines.
Plate and Sheet Metal Working, Safety Code for.
Power Control, Mechanical, Safety Code for.
Refrigeration, Mechanical, Safety Code for.
Sanitation, Industrial, Safety Code for.
Tanneries, Safety Code for.
Textiles, Safety Code for.
Tools, Machine, Safety Code for.
Colors for Traffic Signals, Safety Code of.
Ventilation Code.
Walkway Surfaces, Safety Code for.
29
IN D E X
Part Section
B
. etc., power
transmission apparatus
located in.........................
Bearings..............................
Care of_....................... .
Facilities for oiling____
Belts:
And ropes, horizontal-.
Care of..........................
Cone-pulley.................
Drives, belt, rope, and
chain..........................
Fasteners......................
Guides................. .......
Horizontal overhead,
discussion of rules__
Horizontal overhead,
guards for.................
On overhead pulleys,
operating rule....... —
Perches........................
Shifters....... —..........
Shifters, clutches, ship
pers, poles, perches,
and fasteners..... .......
Shippers and shipper
poles....... ...................
Tighteners....................
Tighteners, discussion
of rules......................Vertical______________
Vertical and inclined—
204
270
502
270-272
220
505
223
220-224
313
214
422
506
312
310
310-313
311
223
221
C
Chain, belt, and rope drives
Chain and rope drives,
horizontal
overhead,
guards for____ _________
Chains and sprockets_____
Chain, sprockets, and gears.
Clutches, shifters, shippers,
poles, perches, and fasten
ers, belt.._____________
Clutches, cut-off couplings,
and clutch pulleys______
Codes, approved and pub
lished, list of___________
Codes in process of develop
ment, list of.___________
Collars and couplings_____
Collars, revolving and split.
Composition and wood
pulleys_________ _______
Cone-pulley belts...............
Connecting rods and cranks
Corrosion, pulleys exposed
to......................................
Couplings...........................
Couplings and collars_____
Cranks and connecting rods
Cut-off couplings, clutches,
and clutch pulleys...........
Part Section
Rule
220-224
423
231
230-232
310-313
300
260-261
215
223
Disk, shield, and “ U ”
guards............ ............... .
Drives, belt, rope, and
chain..... ...........................
Drives, friction...................
Rule
410-412
220-224
240
E
Equipment:
Care of..........................
Mechanical p o w e r transmission.............
Periodic inspection of_.
Extension piston rods........
500-507
200-204
500
102
F a s t e n e r s , s h ift e r s ,
clutches, shippers, poles,
and perches, belt............ .
Flywheels...........................
Friction drives....................
310-313
100
240
G
Gears...................................
Hand-operated, discus
sion of rules....... .......
Sprockets, and chains..
Governor balls....................
Guards:
Approved materials___
Clutches, cut-off cou
plings, and clutch
pulleys.......................
Design o f................... .
Friction drives............ .
Horizontal overhead
belts_________ _____
Horizontal overhead
rope and chain drives.
Horizontal shafting___
Keys, set screws, and
other projections____
Method of manufac
ture............................
M in im u m req u ire
ments, materials and
dimensions.................
Pulleys______________
Rails and toe boards. __
Standard materials for.
Standards................ .
Vertical and inclined
shafting.................... .
Wood, approved ma
terials and dimensions.
230
230-232
103
420-424
300
401
240
422
423
2bl
250
402
42
21
42
40
40-42
420
210
424
400
400-424
202
421
101
216
261
260-261
Hangers, care and inspec
tion of..............................
101
I
300
Installation of shafting.......
Interpretations....... Page 1
401
Keys, set screws, and other
projections, elimination,
or guarding......................
D
50
503
20
200
25
250
K
Definitions.........Pages 1, 2
Design of guards.................
Discussion of rules..............
Disk guards.........................
"410
2
31
32
INDEX
Part Section
L
Ladders___________ ______
Lubrication, o p e r a t in g
rule_________ _________
Rule
2
27
271
5
50
507
M
Materials, for standard
guards__________ ____
Mechanical power-trans
mission equipment..........
4
40
400
2
20
200-204
0
Oilers’ runways and plat
forms...............................
Oiling, facilities for, and
bearings............................
Oiling, openings for. ..........
Openings for oiling_______
Operating rules__________
2
27
272
2
2
2
5
27
23
23
50
270-272
232
232
500-507
P
Perches, fasteners, shifters,
clutches, shippers, and
poles, belt.........................
Piston rods, extension.........
Platforms and runways,
oilers’ . ..............................
Poles, perches, fasteners,
shifters, clutches, and
shippers, belt...................
Power control, discussion
of rules________________
Power-transmission appa
ratus located in base
ments............... ...............
Power-transmission equip
ment, discussion of rules.
Power-transmission equip
ment, mechanical............
Prime movers and guards _.
Projections, set screws, and
keys, elimination or
guarding_______________
Pulleys__________________
Broken, discussion of
rules ______________
Broken, not to be used.
Care of.........................
Exposed to corrosion...
Location of___________
Out of service
Speeds.. ____________
Wood and composition.
3
1
31
10
310-313
102
2
27
272
3
31
310-313
6
2
20
204
6
2
1
20 200-204
10 100-103
2
2
25
21
250
210-217
6
2
5
2
2
2
2
2
21
50
21
21
21
21
21
212
504
216
211
217
213
215
Part Section
R
References...........................
Rope and chain drives,
horizontal overhead,
guards for______________
Rope, belt, and chain
drives................................
Ropes and belts, horizontal.
Runways and platforms,
oilers’ _________________
S
Scope.......................Page 1
Set screws, keys, and other
projections, elimination
or guarding.
_________
Shaft ends, projecting_____
Shafting . ____________
Care of. ____________
Horizontal, guarding.. .
Vertical and inclined,
guarding__________
Shield, disk, and “ U ”
guards_________________
Shield guards.................... .
Shipper poles and belt ship
pers___________________
Sprockets and chains..........
Sprockets, gears, and chains
Standard guards, general
requirements....................
Standard guards, method
of manufacture_________
Starting and stopping de
vices _________________
T
Tail rods or extension pis
ton rods_______ ____ ___
Toe boards and guard rails.
U
“ U ” guards______________
“ U,” disk, and shield
guards_________________
V
Vertical and inclined belts.
Vertical belts_____________
Vertical shafting, guarding.
W
Wood and composition pul
leys___________________
Wood guards, approved
materials ____________
AD D ITIO N A L COPIES
OF THIS PUBLICATION MAY BE PROCURED FROM
THE SUPERINTENDENT OF DOCUMENTS
U.S.GOVERNMENT PRINTING OFFICE
WASHINGTON, D. C.
AT
10 CENTS PEE COPY
V
Rule
7
4
42
423
2
2
22
22
220-224
220
2
27
272
2
2
2
5
2
25
20
20
50
20
250
203
200-204
501
201
2
20
202
4
4
41
41
410-412
411
3
2
2
31
23
23
311
231
230-232
4
40
400-402
4
40
402
3
30,31
300-313
1
4
10
42
102
424
4
41
412
4
41
410-412
2
2
2
22
22
20
221
222
202
2
21
215
4
42
421
@FedFRASER