Pennsylvania Code › Title 34 - LABOR AND INDUSTRY › Part I - Department of Labor and Industry › Chapter 29 - MECHANICAL APPARATUS-MISCELLANEOUS › Subchapter C - MECHANICAL POWER TRANSMISSION APPARATUS › SPECIFICATIONS › Section 29.135 - Materials and construction of guards

Current through Register Vol. 54, No. 28, July 13, 2024
(a) Wood shall be sound, tough and free from
					 any loose knots.
(b) Guards shall
					 be made of planed lumber not less than 1 inch rough board measure and edges and
					 corners rounded off.
(c) Wood
					 guards shall be securely fastened together with wood screws, hard wood dowel
					 pins, bolts or rivets.
(d) 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 §
											29.134(d) and (e)
					 (relating to construction of guards).
(e) Construction of standard wood railings
					 shall be according to the requirements of § 29.134(g).
(f) Machinery required to be guarded in the
					 slate industry shall be equipped with guards of slate construction at least one
					 inch in thickness except where the installation of the guards prevents proper
					 light from being shed on any operation.
(g) Guards for horizontal overhead belts,
					 ropes and chains shall be according to the following specifications:
(1) Guards for horizontal overhead belts,
					 ropes and chains shall run the entire length of the belt, rope or chains and
					 follow the line of the pulleys or sprockets to the ceiling or be carried to the
					 nearest wall, thus enclosing the belt, rope or chain effectively. When belts,
					 ropes or chains are so located as to make it impracticable to carry the guard
					 to the wall or ceiling, construction of the guard shall be such as to enclose
					 completely the top and bottom runs of the belt, rope or chain and the face of
					 pulleys or sprockets.
(2) The guard
					 and all its supporting members shall be securely fastened to the 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.
(3) Suitable reinforcements shall be provided
					 for the ceiling rafters or overhead floor beams when 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, rope, or chain comes in contact, shall be smooth and free from
					 all projections of any character, except when construction demands it;
					 protruding shallow roundhead rivets may be used. Overhead belt guards shall be
					 at least 1/4 wider than the 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. In overhead silent chain-drive guards where the chain
					 is held from lateral displacement on the sprockets, the side clearance required
					 on drives of 20 inch centers or under shall be not less than 1/4 inch from the
					 nearest moving chain part and on drives of over 20 inch centers a minimum of
					 1/2 inch from the nearest moving chain part.
(4) In overhead rope or chain guards a side
					 guard member of the same solid filling material shall be carried up in a
					 vertical position 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
					 encloses thus forming a trough. These side filler members shall be reinforced
					 on the edges with 1-1/2 inch by 1/4 inch flat steel, riveted to the filling
					 material at not greater than 8 inch centers; the reinforcing strip shall be
					 fastened or bolted to all guard-supporting members with at least one 3/8 inch
					 rivet or bolt at each intersection, and the ends shall be secured to the
					 ceiling with lag screws or bolts.