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                                   G1910.219
Starting with: 1910.219 - Mechanical power-transmission apparatus.


 1910.219  Mechanical power-transmission apparatus.

(a) General requirements.
(1) This section covers all types and shapes of power-transmission belts,
except the following when operating at two hundred and fifty (250) feet
per minute or less: (i) Flat belts one (1) inch or less in width, (ii)
flat belts two (2) inches or less in width which are free from metal
lacings or fasteners, (iii) round belts one-half ( 1/2) inch or less in
diameter; and (iv) single strand V-belts, the width of which is thirteen
thirty-seconds ( 13/32) inch or less.
(2) Vertical and inclined belts (paragraphs (e) (3) and (4) of this section)
if not more than two and one-half (2 1/2) inches wide and running at a
speed of less than one thousand (1,000) feet per minute, and if free
from metal lacings or fastenings may be guarded with a nip-point belt
and pulley guard.
(3) For the Textile Industry, because of the presence of excessive deposits
of lint, which constitute a serious fire hazard, the sides and face
sections only of nip-point belt and pulley guards are required, provided
the guard shall extend at least six (6) inches beyond the rim of the
pulley on the in-running and off-running sides of the belt and at least
two (2) inches away from the rim and face of the pulley in all other
directions.
(4) This section covers the principal features with which power transmission
safeguards shall comply.
(b) Prime-mover guards-
(1) Flywheels. Flywheels located so that any part is seven (7) feet or less
above floor or platform shall be guarded in accordance with the
requirements of this subparagraph:
(i) With an enclosure of sheet, perforated, or expanded metal, or woven
wire;
(ii) With guard rails placed not less than fifteen (15) inches nor more
than twenty (20) inches from rim. When flywheel extends into pit or is
within 12 inches of floor, a standard toeboard shall also be provided;
(iii) When the upper rim of flywheel protrudes through a working floor, it
shall be entirely enclosed or surrounded by a guardrail and toeboard.
(iv) For flywheels with smooth rims five (5) feet or less in diameter,
where the preceding methods cannot 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 four (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. This subdivision does not apply to flywheels with
solid web centers.
(v) 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.
(vi) Wherever flywheels are above working areas, guards shall be installed
having sufficient strength to hold the weight of the flywheel in the
event of a shaft or wheel mounting failure.
(2) Cranks and connecting rods. Cranks and connecting rods, when exposed to
contact, shall be guarded in accordance with paragraphs (m) and (n) of
this section, or by a guardrail as described in paragraph (o)(5) of this
section.
(3) Tail rods or extension piston rods. Tail rods or extension piston rods
shall be guarded in accordance with paragraphs (m) and (o) of this
section, or by a guardrail on sides and end, with a clearance of not
less than fifteen (15) nor more than twenty (20) inches when rod is
fully extended.
(c) Shafting-
(1) Installation.
(i) Each continuous line of shafting shall be secured in position against
excessive endwise movement.
(ii) Inclined and vertical shafts, particularly inclined idler shafts,
shall be securely held in position against endwise thrust.
(2) Guarding horizontal shafting.
(i) All exposed parts of horizontal shafting seven (7) feet or less from
floor or working platform, excepting runways used exclusively for
oiling, or running adjustments, shall be protected by a stationary
casing enclosing shafting completely or by a trough enclosing sides
and top or sides and bottom of shafting as location requires.
(ii) Shafting under bench machines shall be enclosed by a stationary
casing, or by a trough at sides and top or sides and bottom, as
location requires. The sides of the trough shall come within at least
six (6) inches of the underside of table, or if shafting is located
near floor within six (6) inches of floor. In every case the sides of
trough shall extend at least two (2) inches beyond the shafting or
protuberance.
(3) Guarding vertical and inclined shafting. Vertical and inclined shafting
seven (7) feet or less from floor or working platform, excepting
maintenance runways, shall be enclosed with a stationary casing in
accordance with requirements of paragraphs (m) and (o) of this section.
(4) Projecting shaft ends.
(i) 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.
(ii) Unused keyways shall be filled up or covered.
(5) Power-transmission apparatus located in basements. All mechanical power
transmission apparatus located in basements, towers, and rooms used
exclusively for power transmission equipment shall be guarded in
accordance with this section, except that the requirements for
safeguarding belts, pulleys, and shafting need not be complied with when
the following requirements are met:
(i) The basement, tower, or room occupied by transmission equipment is
locked against unauthorized entrance.
(ii) The vertical clearance in passageways between the floor and power
transmission beams, ceiling, or any other objects, is not less than
five feet six inches (5 ft. 6 in.).
(iii) The intensity of illumination conforms to the requirements of ANSI
A11.1-1965 (R-1970).
(iv) [Reserved]
(v) The route followed by the oiler is protected in such manner as to
prevent accident.
(d) Pulleys-
(1) Guarding. Pulleys, any parts of which are seven (7) feet or less from
the floor or working platform, shall be guarded in accordance with the
standards specified in paragraphs (m) and (o) of this section. Pulleys
serving as balance wheels (e.g., punch presses) on which the point of
contact between belt and pulley is more than six feet six inches (6 ft.
6 in.) from the floor or platform may be guarded with a disk covering
the spokes.
(2) Location of pulleys.
(i) 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
insufficient clearance exists.
(ii) [Reserved]
(3) Broken pulleys. Pulleys with cracks, or pieces broken out of rims, shall
not be used.
(4) Pulley speeds. Pulleys intended to operate at rim speed in excess of
manufacturers normal recommendations shall be specially designed and
carefully balanced for the speed at which they are to operate.
(e) Belt, rope, and chain drives-
(1) Horizontal belts and ropes.
(i) Where both runs of horizontal belts are seven (7) feet or less from
the floor level, the guard shall extend to at least fifteen (15)
inches above the belt or to a standard height (see Table O-12), except
that where both runs of a horizontal belt are 42 inches or less from
the floor, the belt shall be fully enclosed in accordance with
paragraphs (m) and (o) of this section.
(ii) In powerplants or power-development rooms, a guardrail may be used in
lieu of the guard required by subdivision (i) of this subparagraph.
(2) Overhead horizontal belts.
(i) Overhead horizontal belts, with lower parts seven (7) feet or less
from the floor or platform, shall be guarded on sides and bottom in
accordance with paragraph (o)(3) of this section.
(ii) Horizontal overhead belts more than seven (7) feet above floor or
platform shall be guarded for their entire length under the following
conditions:
(a) If located over passageways or work places and traveling 1,800 feet
or more per minute.
(b) If center to center distance between pulleys is ten (10) feet or
more.
(c) If belt is eight (8) inches or more in width.
(iii) 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:
(a) Completely barred by a guardrail or other barrier in accordance with
paragraphs (m) and (o) of this section; or
(b) 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 powerplants only the
lower run of the belt need be guarded.
(iv) Overhead chain and link belt drives are governed by the same rules as
overhead horizontal belts and shall be guarded in the same manner as
belts.
(3) Vertical and inclined belts.
(i) Vertical and inclined belts shall be enclosed by a guard conforming to
standards in paragraphs (m) and (o) of this section.
(ii) All guards for inclined belts shall be arranged in such a manner that
a minimum clearance of seven (7) feet is maintained between belt and
floor at any point outside of guard.
(4) Vertical belts. Vertical belts running over a lower pulley more than
seven (7) feet above floor or platform shall be guarded at the bottom in
the same manner as horizontal overhead belts, if conditions are as
stated in paragraphs (e)(2)(ii) (a) and (c) of this section.
(5) Cone-pulley belts.
(i) 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.
(ii) 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.
(iii) 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.
(6) Belt tighteners.
(i) Suspended counterbalanced tighteners and all parts thereof shall be of
substantial construction and securely fastened; the bearings shall be
securely capped. Means must be provided to prevent tightener from
falling, in case the belt breaks.
(ii) Where suspended counterweights are used and not guarded by location,
they shall be so encased as to prevent accident.
(f) Gears, sprockets, and chains-
(1) Gears. Gears shall be guarded in accordance with one of the following
methods:
(i) By a complete enclosure; or
(ii) By a standard guard as described in paragraph (o) of this section, at
least seven (7) feet high extending six (6) inches above the mesh
point of the gears; or
(iii) 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 six (6) feet from the floor a disk guard or a complete
enclosure to the height of six (6) feet shall be required.
(2) Hand-operated gears. Paragraph (f)(1) of this section 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. However, the guarding of
these gears is highly recommended.
(3) Sprockets and chains. All sprocket wheels and chains shall be enclosed
unless they are more than seven (7) feet above the floor or platform.
Where the drive extends over other machine or working areas, protection
against falling shall be provided. This subparagraph does not apply to
manually operated sprockets.
(4) Openings for oiling. When frequent oiling must be done, openings with
hinged or sliding self-closing covers shall be provided. All points not
readily accessible shall have oil feed tubes if lubricant is to be added
while machinery is in motion.
(g) Guarding friction drives. The driving point of all friction drives when
exposed to contact shall be guarded, all arm or spoke friction drives and
all web friction drives with holes in the web shall be entirely enclosed,
and all projecting belts on friction drives where exposed to contact shall
be guarded.
(h) Keys, setscrews, and other projections.
(1) All projecting keys, setscrews, and other projections in revolving parts
shall be removed or made flush or guarded by metal cover. This
subparagraph does not apply to keys or setscrews within gear or sprocket
casings or other enclosures, nor to keys, setscrews, or oilcups in hubs
of pulleys less than twenty (20) inches in diameter where they are
within the plane of the rim of the pulley.
(2) It is recommended, however, that no projecting setscrews or oilcups be
used in any revolving pulley or part of machinery.
(i) Collars and couplings-
(1) 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.
(2) Couplings. Shaft couplings shall be so constructed as to present no
hazard from bolts, nuts, setscrews, or revolving surfaces. Bolts, nuts,
and setscrews 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.
(j) Bearings and facilities for oiling. All drip cups and pans shall be
securely fastened.
(k) Guarding of clutches, cutoff couplings, and clutch pulleys-
(1) Guards. Clutches, cutoff couplings, or clutch pulleys having projecting
parts, where such clutches are located seven (7) feet or less above the
floor or working platform, shall be enclosed by a stationary guard
constructed in accordance with this section. A "U" type guard is
permissible.
(2) Engine rooms. In engine rooms a guardrail, preferably with toeboard, may
be used instead of the guard required by paragraph (k)(1) of this
section, provided such a room is occupied only by engine room
attendants.
(l) Belt shifters, clutches, shippers, poles, perches, and fasteners-
(1) Belt shifters.
(i) Tight and loose pulleys on all new installations made on or after
August 31, 1971, shall be equipped with a permanent belt shifter
provided with mechanical means to prevent belt from creeping from
loose to tight pulley. It is recommended that old installations be
changed to conform to this rule.
(ii) 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. Where belt shifters are not directly located
over a machine or bench, the handles shall be cut off six feet six
inches (6 ft. 6 in.) above floor level.
(2) Belt shippers and shipper poles. The use of belt poles as substitutes
for mechanical shifters is not recommended.
(3) 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.
(4) Belt fasteners. Belts which of necessity must be shifted by hand and
belts within seven (7) feet of the floor or working platform which are
not guarded in accordance with this section shall not be fastened with
metal in any case, nor with any other fastening which by construction or
wear will constitute an accident hazard.
(m) Standard guards-general requirements-
(1) Materials.
(i) Standard conditions shall be secured by the use of the following
materials. Expanded metal, perforated or solid sheet metal, wire mesh
on a frame of angle iron, or iron pipe securely fastened to floor or
to frame of machine.
(ii) All metal should be free from burrs and sharp edges.
(2) Methods of manufacture.
(i) Expanded metal, sheet or perforated metal, and wire mesh shall be
securely fastened to frame.
(n) [Reserved]
(o) Approved materials-
(1) Minimum requirements. The materials and dimensions specified in this
paragraph shall apply to all guards, except horizontal overhead belts,
rope, cable, or chain guards more than seven (7) feet above floor, or
platform.
(i) [Reserved]
(a) All guards shall be rigidly braced every three (3) feet or
fractional part of their height to some fixed part of machinery or
building structure. Where guard is exposed to contact with moving
equipment additional strength may be necessary.
(2) Wood guards.
(i) Wood guards may be used in the woodworking and chemical industries, in
industries where the presence of fumes or where manufacturing
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 undesirable. In all other
industries, wood guards shall not be used.
(3) Guards for horizontal overhead belts.
(i) 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 enclosing the belt effectively.
Where belts are so located as to make it impracticable to carry the
guard to wall or ceiling, construction of guard shall be such as to
enclose completely the top and bottom runs of belt and the face of
pulleys.
(ii) [Reserved]
(iii) Suitable reinforcement shall be provided for the ceiling rafters or
overhead floor beams, where such is necessary, to sustain safely 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 and free from all
projections of any character, except where construction demands it;
protruding shallow roundhead 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 six (6) inches
on each side. Overhead rope drive and block and roller-chain-drive
guards shall be not less than six (6) inches wider than the drive on
each side. In overhead silent chain-drive guards where the chain is
held from lateral displacement on the sprockets, the side clearances
required on drives of twenty (20) inch centers or under shall be not
less than one-fourth inch from the nearest moving chain part, and on
drives of over twenty (20) inch centers a minimum of one-half inch
from the nearest moving chain part.
(4) Guards for horizontal overhead rope and chain drives. Overhead-rope and
chain-drive guard construction shall conform to the rules for
overhead-belt guard.
(5) Guardrails and toeboards.
(i) Guardrail shall be forty-two (42) inches in height, with midrail
between top rail and floor.
(ii) Posts shall be not more than eight (8) feet apart; they are to be
permanent and substantial, smooth, and free from protruding nails,
bolts, and splinters. If made of pipe, the post shall be one and
one-fourth (1 1/4) inches inside diameter, or larger. If made of metal
shapes or bars, their section shall be equal in strength to that of
one and one-half (1 1/2) by one and one-half (1 1/2) by
three-sixteenths ( 3/16) inch angle iron. If made of wood, the posts
shall be two by four (2 x 4) inches or larger. The upper rail shall be
two by four (2 x 4) inches, or two one by four (1 x 4) strips, one at
the top and one at the side of posts. The midrail may be one by four
(1 x 4) inches or more. Where panels are fitted with expanded metal or
wire mesh as noted in Table O-12 the middle rails may be omitted.
Where guard is exposed to contact with moving equipment, additional
strength may be necessary.
(iii) Toeboards shall be four (4) inches or more in height, of wood,
metal, or of metal grill not exceeding one (1) inch mesh.
(p) Care of equipment-
(1) General. All power-transmission equipment shall be inspected at
intervals not exceeding 60 days and be kept in good working condition at
all times.
(2) Shafting.
(i) Shafting shall be kept in alignment, free from rust and excess oil or
grease.
(ii) Where explosives, explosive dusts, flammable vapors or flammable
liquids exist, the hazard of static sparks from shafting shall be
carefully considered.
(3) Bearings. Bearings shall be kept in alignment and properly adjusted.
(4) 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.
(5) Pulleys.
(i) Pulleys shall be kept in proper alignment to prevent belts from
running off.
(6) Care of belts.
(i) [Reserved]
(ii) Inspection shall be made of belts, lacings, and fasteners and such
equipment kept in good repair.
(7) Lubrication. The regular oilers shall wear tight-fitting clothing.
Machinery shall be oiled when not in motion, wherever possible.