1、c % snatch, safety locking. Type IV - Blocks; cargo hoisting. 1.2.1 Sizes. The size of the block shall be listed as the outside diameter of the sheave to conform with current commercial practice. Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use i
2、n improving this document should be addressed to: Commander, Naval Sea Systems Command, SEA 5523, Department of the Navy, Washington, DC 20362-5101 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. AMSC N/A FS
3、C 3940 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-, MIL-B-24L41A 39 W 979970b 0457889 7 W 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Specifications. s
4、tandards, and handbooks. The following specifi- cations, standards, and handbooks form a part of this documeng to the extent specified herein. those listed in the issue of the Department of Defense Index of Specifications and Standards (DODISS) and supplement thereto, cited in the solicitation (see
5、6.2). Unless otherwise specified, the issues of these documents are SPECIFICATIONS FEDERAL PPP-F-320 - Fiberboard; Corrugated and Solid, Sheet Stock (Container Grade) and Cut Shapes. MI LI TARY -MIL-B-3865 - Blocks, Rope Tackle: Packaging of. MIL-L-19140 - Lumber and Plywood, Fire-Retardant Treated.
6、 STANDARDS FEDERAL FED-STD-H28 - Screw Threads Standards for Federal Services. MILITARY MIL-STD-130 - Identification Marking of U.S. Military Property. MIL-STD-278 - Welding and Casting Standard. (Unless otherwise indicated, copies of federal and military specifications, standards, and handbooks are
7、 available from the Standardization Documents Order Desk, BLDG. 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094.) 2.2 Non-Government Dublications. The following document(s) form a part of this document to the extent specified herein, issues of the documents which are DOD adopted are those listed
8、 in the issue of the DODISS cited in the solicitation. documents not listed in the DODISS are the issues of the documents cited in the solicitation (see 6.2). Unless otherwise specified, the Unless otherwise specified, the issues of AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) General Applicati
9、on. (DOD adopted) A 27 - Standard Specification for Steel Castings, Carbon, for A 36 - Standard Specification for Structural Steel, (DOD adopted) A 108 - Standard Specification for Steel Bars, Carbon, Cold- Finished, Standard Quality. (DOD adopted) A 109 - Standard Specification for Steel, Strip, Ca
10、rbon, Cold- Rolled. (DOD adopted) A 148 - Standard specification for Steel Castings High Strength for Structural Purposes. 2 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- MIL-B-2414LA 39 m 999990b 045790 3 m Sheave ASTM (Continued) A 153 - Stand
11、ard Specification for Zinc Coating (Hot-Dip) on Iron A 569 - Standard Specification for Steel, Carbon (0.15 Maximum, and Steel Hardware. (DOD adopted) Percent) Hot-Rolled Sheet and Strip Commercial Quality. (DOD adopted) Alloy, for General Industrial Use. (DOD adopted) Impregnated) . A 668 - Standar
12、d Specification for Steel Forgings, Carbon and B 438 - Standard Specification for Sintered Bronze Bearings (Oil (Application for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.) (Non-Government standards and other publications a
13、re normally available from These documents also the organizations that prepare or distribute the documents. may be available in or through libraries or other informational services.) 2.3 Order of Precedence. In the event of a conflict between the text of this document and the references cited herein
14、, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. REQUIREMENTS Working load (pounds) 3.1 First article. When specified (see 6.2), a sample shall be subjected to first article i
15、nspection (see 6.4) in accordance with 4.3. 3.2 Desien and construction. Block design shall be as shown in tables I through IV and on figures 1 through 5, as to type, class, style, size, and rig. Each block shall be free from any defects that would adversely affect the performance or maintainability
16、 of individual components. be manufactured to standard tolerances to permit replacement without requiring modification. adjacent parts. Replacement parts shall All parts subject to wear shall be removable without dismantling Size Wire dia. DBL 5,000 7,000 9,000 12,000 14,000 30,000 36,000 6 8 10 12
17、14 16 18 TRIPLE 6,000 9,000 14,000 16,000 36,000 40,000 11,000 3/8 1/2 5/8 5/8 3/4 7/8-1 1 width 6 8 10 12 14 16 18 1 1 - 1/4 1 - 1/4 1 - 1/2 1 - 1/2 1-3/4 1-3/4 3/4 7/8 7/8 1 1 - 1/8 1-1/2 1 - 1/2 4,000 5,000 6,000 8,000 16,000 10,000 20,000 3 Provided by IHSNot for ResaleNo reproduction or network
18、ing permitted without license from IHS-,-,-MIL-B-ZLlL41A 39 W 9999906 OLl57891 5 if MIL-B-24141A(SH) TABLE II. Twe II blocks, diamond Dattem. Sheave I Working load (pounds) Tl-zTzz Wire dia. Size 6 8 10 12 14 16 ia 1 1 - 1/4 1 - 1/4 1-1/2 1-1/2 1 - 3/4 1- 3/4 3/4 7/a 718 i-i/a I 1-1/2 1 - 1/2 1 4,00
19、0 5,000 6 ) O00 a, ooo 10 ) O00 16,000 20,000 5 O00 7,000 9,000 12,000 14,000 30,000 36,000 6 ) O00 9 O00 Il, O00 14,000 16,000 36,000 40,000 6 8 10 12 14 16 ia TABLE III. Tvue III blocks. snatch. - Size Load (pounds) Sheave Rim THK - OD 4 6 8 10 12 14 16 18 20 20 - - Center pin Wire dia. Working O
20、2,000 a ) ooo 10,000 12,000 15,000 20 O00 24,000 28,000 4,000 6 ) O00 4 6 8 10 12 14 16 18 20 20 3/8 3/8 - 1/2 1/2 - 5/8 5/8 3/4 3/4- 7/8 718 -1 1 1 - 1/4 1-1/2 3/4 1 1-1/4 1 - 1/4 1 - 1/2 1 - 1/2 1-3/4 1-3/4 2 - 1/4 2 - 1/4 1/2 3/4 7/8 i - i/a 1 - 1/2 I- 1/2 1 - 3/4 1 - 3/4 1 1 - 1/4 TABLE IV. Twe
21、IV blocks, cargo hoist. Sheave Load (pounds) Rim OD THK Working 12 1-3/4 10 ) O00 14 1-3/4 16,000 16 - 20,000 ia - 20 ) O00 Wire dia. Size 12 14 16 ia 3/4 3/4- 7/8 3/4- 1 - 1/4 1/4- 1 - 1/4 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-7 MIL-B-24
22、24LA 39 9797706 0457872 7 W 3.3 Material. Material shall be as specified herein. Material not specifically specified shall be selected by the manufacturer and shall be subject to all provisions of this specification. Material shall be new and unused. 3.3.1 Castines. Castings shall be of uniform qual
23、ity, free of blowholes, porosity, hard spots, shrinkage defects, cracks, or other injurious defects. Strength and other essential physical properties of the castings shall conform to ASTM A 27 for carbon steel and ASTM A 148 for carbon and low alloy steel. 3.3.2 Forgings. Forgings shall be of unifor
24、m quality, free of flash, scale, cracks, hard spots, cold shuts, and excessive cooling stresses. Strength and other essential physical properties of the forgings shall conform to ASTM A 668. 3.3.3 Weldine;. Welding, if necessary, shall be performed in accordance with MIL-STD-278. Welding shall not b
25、e used to repair blocks. 3.3.4 Fastening devices. Screws, pins, bolts, and similar parts subject to removal, tightening or adjuscment shall not be swaged, peened, staked or otherwise permanently deformed. 3.3.5 Threads. Threaded parts shall be in accordance with the applicable requirements of FED-ST
26、D-H28. 3.3.6 Surface. Castings, forgings, stampings and welded parts shall be thoroughly cleaned and free of sand, dirt, scale, flux, or other harmful or extraneous materials. External surfaces shall be free from burrs, sharp edges and corners. necessary tolerances to provide the required stability
27、in operation. roughness of bearing surfaces shall not reduce bearing areas appreciably or detract from appearance, All bearing surfaces between matching parts shall be finished to the Surface 3.3.7 Galvanizine;. Metal surfaces of blocks except bearing surfaces and bushings shall be hot dip galvanize
28、d in accordance with ASTM A 153, class B3. basic metal shall be clean and free from defects that will impair appearance or protective value of the coating. component parts. The Galvanizing shall be done prior to assembly of 3.3.8 Recovered materials. Unless otherwise specified herein, all equipment,
29、 material, and articles incorporated in the products covered by this specification shall be new and may be fabricated using materials produced from recovered materials to the maximum extent practicable without jeopardizing the intended use. The term lgrecovered materials“ means materials which have
30、been collected or recovered from solid waste and reprocessed to become a source of raw materials, as opposed to virgin raw materials. interpreted to mean that the use of used or rebuilt products is allowed under this specification unless otherwise specifically specified. None of the above shall be 3
31、.4 Rig assemblies. Blocks and fittings of corresponding size and strength shall be assembled into rigs and identified by rig numbers (see 3.5 and figure 5). Special blocks and rigs not designated on figure 5 shall be assembled as specified in the contract or order. 5 Provided by IHSNot for ResaleNo
32、reproduction or networking permitted without license from IHS-,-,-3.5 Identification markincrs. Each block assembly shall be permanently and legibly marked by stamping the shell plate with the manufacturers name or trademark, the safe working load, and the sheave diameter. Abbreviations may be used,
33、 Identification marking shall be in accordance with MIL-STD-130. 3.6 Details of tmes I. II. III. and IV blocks, 3.6.1 Block comonents. 3.6.1.1 Shells, Shell plates shall be made of steel casting, structural steel, or carbon steel hot-rolled sheet, as required, conforming to ASTM A 27, A 36, or A 159
34、, respectively. The edges shall be well rounded. 3.6.1.2 Straw. Steel straps shall be made of structural steel, cold-rolled carbon steel or hot-rolled carbon steel as required, conforming to ASTM A 36, A 109, or A 569, respectively. Steel straps shall support the center pin and transmit sheave loads
35、 to the fitting (hook, shackle, swivel, and so forth) as required. 3.6.1.3 Sheaves. Unless otherwise specified in the contract or order, sheaves shall be cast steel conforming to ASTM A 27 or forged steel conforming to ASTM A 688, and shall be designed to prevent cutting action on the rope. The rim
36、and tread section of each sheave shall be properly grooved to fit the contour of the rope under load conditions. and shall be designed so that only the hub bears against the shell. shall not exceed 1/8 inch. shall conform to minimum dimensions listed in tables I, II, III, and IV. The sheaves shall b
37、e concentric with the bore, Side play Sheaves shall have a smooth-running action. Sheaves 3.6.1.4 Bushings. Each sheave shall be furnished with a one-piece bronze bushing conforming to ASTM B 438, grade 1, class A, type II, which shall be pressed into the sheave with sufficient tightness to prevent
38、slippage under extreme loads. the hub and shall have a minimum wall thickness of 3/16 inch. The bushing shall be equal in length to the sheave thickness at 3.6.1.5 Roller bearings. - Bearings shall be tapered roller bearings, which can take both load and side thrust and hold the sheave centrally so
39、it cannot chafe or wear on the sides. chamber with felt washers to retain the grease and exclude dirt. The bearings shall be locked in a grease packed 3.6.1.6 Center Din. The center pin shall be of carbon steel conforming to ASTM A 108, having a carbon content of 0.25 to 0.50 percent. transmit the s
40、heave load to the shell or straps without rotating (see tables I, II, and III for minimum pin diameters). The pin shall 3.6.1.7 Fittings. Each block shall include a shackle, swivel shackle, hook or swivel hook, as specified (see 6.2) using a rig number shown on figure 5 to identify the type of fitti
41、ng required, Safety factors of fittings shall be as specified in 3.7.1. 3.6.1.8 Hook. The hook shall be drop forged from carbon steel, with heavier Hook safety factors shall be sections at the areas which take the maximum stress. as specified in 3.7.1. 6 Provided by IHSNot for ResaleNo reproduction
42、or networking permitted without license from IHS-,-,-flIL-B-24141A 39 m 997970b Oq57874 O m MIL-B-2414lA(SH) 3.6.1.9 Becket. The becket shall be formed by the extension of the strap ends, and shall show no distortion with the wire rope dead ended at the becket and the loads specified in tables I and
43、 II suspended from the hook. 3.6.1.10 SDacers and roller mides. Spaces shall be provided as required to make the block a strong, rugged unit with the required sheave clearances. guides shall be provided as required to prevent the wire from coming out of the sheaves when the block is overhauled. Roll
44、er 3.6.2 Twe I blocks. oval Dattern. Type I blocks shall be in accordance with 3.2, figure 1, table I, and as specified in 3.6.1.1 through 3.6.1.4 and 3.6.1.6 through 3.6.1.10. 3.6.3 Twe II blocks. diamond Dattern. Type II blocks shall be in accordance with 3.2, figure 2, table II, and as specified
45、in 3.6.1.1 through 3.6.1.4 and 3.6.1.6 through 3.6.1.10. 3.6.4 Twe III blocks: snatch. safety locking. Type III blocks shall be in accordance with 3.2, figure 3, table III, and as specified in 3.6.1.3, 3.6.1.4, 3.6.1.6, 3.6.1.10 and 3.6.4.1 through 3.6.4.3. 3.6.4.1 Shell. The shell shall be as speci
46、fied in 3.6.1.1 and shall have a rope guard indented around the top of the shell to prevent jamming of the rope between the sheave and the shell. 3.6.4.2 Fittings. Blocks shall be fitted with either a swivel hook or a swivel eye with shackle as specified in the contract (see 6.2). 3.6.4.3 Safetv loc
47、king device. Each block shall be provided with a self- locking safety device that will hold the block securely closed under load (see 6.2). 3.6.5 Twe IV blocks, cargo hoistinq. Type IV blocks shall be in accordance with 3.2, table IV, figure 4 and as specified in 3.6.1.3, 3.6.1.5 and 3.6.5.1 through
48、 3.6.5.3. 3.6.5.1 Shell, Shells shall be as specified in 3.6.1.1 with recessed mortise. 3.6.5.2 Center Din. The center pin shall be as specified in 3.6.1.6 and shall contain a recessed grease fitting in the head and grease grooves. 3.6.5.3 Fittinvs. Blocks shall be rigged as rig 1 and rig 3; in addi
49、tion, they may be self-adjusters shown as rig 15. All swivel connections shall contain a recessed Alemite grease fitting, or equal, and all fittings shall be in accordance with 3.6.1.7. 3.7 Phvsical reauirements. 3.7.1 Safe working load (Sa). The SWL shall be based on a safety factor of The SWL, rope, 5 on the mnimum breaking strength of the complete block assembly. and sheave size shall be as shown in tables I, II, III, and IV as applicable for the type b
