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(a) Requirement for Car Frames.
Every hoist car shall have a frame. The car frame and platform may be an integral part of the car construction.
(b) Guide Members.
Car frames shall be guided on each guide member by upper and lower guide shoes or rollers attached to the frame.
(c) Design of Car Frames and Guide Shoes or Rollers.
The frame and its guide shoes or rollers shall be designed to withstand the forces resulting under the loading conditions for which the hoist is designed.
(d) Underslung or Subpost Car Frames.
The vertical distance between the top and bottom guide shoes of a hoist car having a subpost car frame, or having an underslung car frame located entirely below the car platform, shall be not less than 40% of the distance between guide rails.
(e) Car Platforms.
Every car shall have a platform consisting of a nonperforated floor attached to a platform frame supported by the car frame and extending over the entire area within the car enclosure. The platform frame members and the floor shall be designed to withstand the forces developed under the loading conditions for which the hoist is designed and installed.
(f) Materials for Car Frames and Platform Frames.
(1) Car frames and outside members of platform frames shall be made of steel or other metals.
(2) Cast iron shall not be used for any part subject to tension, torsion, or bending.
EXCEPTION: Exceptions are guide rollers, guide shoes and compensating rope anchorages.
(3) Steel, where used in the construction of car frames and platforms, shall conform to the requirements given in Sections 1604.16(f)(3)(A) and 1604.16(f)(3)(B).
EXCEPTION: Steels of greater strength than those specified may be used provided they have an elongation of not less than 22% in a length of 2 inches and provided that the stresses and deflections conform to the requirements of Sections 1604.16(h) and 1604.16(i), respectively.
(A) Car Frame and Platform Frame Members.
Steel shall be rolled, forged, or cast, conforming to the requirements of the following American National Standards:
1. Rolled and Formed Steel: American National Standard Specification for Structural Steel, G41.5-1970 (ASTM A36-69) or American National Standard Specification for Low and Intermediate Tensile Strength Carbon Steel Plates of Structural Quality, G24.2-1972 (ASTM A283-70a), Grade D.
2. Forged Steel: American National Standard Specification for Carbon Steel Forgings for General Industrial Use, G55.20-1969 (ASTM A235-67), Class C.
3. Cast Steel: American National Standard Specifications for Mild to Medium strength Carbon Steel Castings for General Application, G50.1-1972 (ASTM A27-71), Grade 60/30.
(B) Rivets, Bolts, and Rods.
Steel used for rivets, bolts, and rods shall conform to the following American National Standards:
1. Rivets: American National Standard Specification for Steel Structural Rivets, G42.2-1968 (ASTM A502-65).
2. Bolts and Rods: American National Standard Specification for Low Carbon Steel Externally and Internally Threaded Standard Fasteners, G38.5-1969 (ASTM A307-68).
(4) Metals other than steel may be used in the construction of car frames and platforms provided the metal used has the essential properties to meet all the requirements for the purpose in accordance with good engineering practice, and provided the stresses and deflections conform to the requirements of Sections 1604.16(h) and 1604.16(i), respectively.
(g) Car Frame and Platform Connections.
Connections between members of car frames and platforms shall be riveted, bolted, or welded, and shall conform to the following requirements:
(1) Bolts. Bolts, where used through sloping flanges of structural members, shall have bolt heads of the tipped head type or shall be fitted with beveled washer.
Nuts, used on sloping flanges of structural members, shall seat on beveled washers.
Welding of parts upon which safe operation depends shall be performed in accordance with the requirements of the American Welding Society D1.1. At the option of the manufacturer, the welders may be qualified by one of the following:
(A) The manufacturer.
(B) A professional consulting engineer.
(C) A recognized testing laboratory.
EXCEPTION: Tack welds not later incorporated into finished welds carrying calculated loads are an exception.
Table 1 Maximum Allowable Stresses* in Car-Frame and Platform Members and Connections, for Steels Specified in Sections 1604.16(f)(3)(A) and 1604.16 (f)(3)(B) Member Type of Maximum Area Basis Stress Stress (psi) Car crosshead............................ Bending 12,500 Gross section Car-frame plank, normal loading.......... Bending 12,500 Gross section Car-frame plank, buffer reaction......... Bending 25,000 Gross section Car-frame uprights (stiles).............. Bending plus 15,000 Gross section tension 18,000 Net section Hoisting-rope hitch...................... Bending plus shapes or plates........................ tension 8,000 Net section Platform framing......................... Bending 12,500 Gross section Platform stringer........................ Bending 15,000 Gross section Threaded brace rods and other tension members except bolts............ Tension 8,000 Net section Bolts.................................... Tension 7,000 Net section Bolts in clearance holes................. Shear 7,000 Actual area in shear plane Bolts in clearance holes................. Bearing 16,000 Gross section Rivets or tight body fit bolts........... Shear 10,000 Actual area in shear plane Rivets or tight body-fit bolts........... Bearing 18,000 Gross section Any framing member, normal loading.......................... Compression 14,000 59L Gross section --- R
* Stresses shall be determined on the basis of a uniformly distributed load over the entire area of the car platform or a single concentrated load placed at the center of the car platform.
(h) Maximum Allowable Stresses in Car Frame and Platform Members and Connections.
The stresses in car frame and platform members and their connections, based on the static load imposed upon them, shall be as follows:
(1) Stresses in steel shall not exceed the stresses listed in Table 1. For steels of greater strength, as permitted by the Exception to Section
1604.16(f)(3), the stresses listed in Table 1 may be increased proportionately based on the ratio of the ultimate strengths.
(2) For metals other than steel, the factor of safety shall be not less than is required for steel as given in Table 1.
(i) Maximum Allowable Deflections of Car Frame and Platform Members.
The deflections of car frame and platform members based on the static load imposed upon them, shall be not more than the following:
(1) For crosshead, 1/960 of the span
(2) For plank, 1/960 of the span
(3) For platform frame members, 1/960 of the span. For uprights (stiles), the moment of inertia shall be not less than determined by the following formula:
KL3 I = ------- 18EH
I = moment of inertia of member, gross section, in4
K = turning moment, in inch-pounds
L = free length of uprights, in inches
E = modules of elasticity
H = vertical center distance between upper and lower guide shoes
(j) Car Frames With Crosshead Sheaves.
Where a hoisting rope sheave is mounted on the car frame, the construction shall conform to the following requirements:
(1) Where multiple sheaves mounted on separate sheave shafts are used, provision shall be made to take the compressive forces, developed by tension in the hoist ropes between the sheaves, on a strut or struts between the sheave shaft supports, or by providing additional compressive strength in the car frame or car frame members supporting the sheave shafts.
(2) Where the sheave shaft extends through the web of a car frame member, the reduction in area of the member shall not reduce the strength of the member below that required. Where necessary, reinforcing plates shall be welded or riveted to the member to provide the required strength. The bearing pressure shall in no case be more than that permitted in Table 1 for bolts in clearance holes.
(3) Where the sheave is attached to the car crosshead by means of a single threaded rod or specially designed member or members in tension, the following requirements shall be met:
(A) The single rod, member, or members in tension shall have a factor of safety 50% higher than the factor of safety required for the suspension wire ropes, but in no case less than fifteen.
(B) The means for fastening the single threaded rod, member, or members in tension to the car frame shall conform to the requirements of Section 1604.16(k).
(k) Hoisting Rope Hitch Plates or Shapes.
Where cars are suspended by hoisting ropes attached to the car frame by means of rope shackles, the shackles shall be attached to steel hitch plates or to structural or formed steel shapes. Such plates or shapes shall be secured to the underside or to the webs of the car frame member with bolts, rivets or welds so located that the tensions in the hoisting ropes will not develop direct tension in the bolts or rivets. The stresses shall not exceed those permitted in Section 1604.7(a)(3)(C).
(l) Platform Side Braces.
Where side bracing and similar members are attached to car frame uprights, the reduction in area of the upright shall not reduce the strength of the upright below that required by Section 1604.16.
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