This standard specifies the types, dimensions, technical requirements, test methods and inspection rules of straight shank hook nuts. This standard applies to straight shank hook nuts in the hook devices on lifting machinery and equipment. JB/T 7687.3-1995 Straight shank hook nuts JB/T7687.3-1995 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Straight shank hook nut
Subject content and scope of application
JB/T7687.3-95
This standard specifies the type, size, technical requirements, test methods and inspection rules of straight shank hook nuts. This standard applies to straight shank hook nuts (hereinafter referred to as nuts) in the hook devices on lifting machinery and equipment. Note: This standard should be used in conjunction with GB10051.1, GB10051.2, GB10051.5 and JB/T7687.2 and JB/T7687.4. 2 Reference standards
GB10051.1
GB 10051.2
GB10051.5
JB/T7687.1
JB/T7687.2
JB/T 7687.4
3 Strength grade of nut
Mechanical properties, lifting capacity, stress and materials of lifting hook Technical conditions of lifting hook with straight handle
Lifting hook
Single hook with straight handle
Rough parts of straight hook beam
Straight hook beam
Hook nut positioning plate
Nuts are divided into 5 strength grades according to their mechanical properties, see Table 1 in Chapter 3 of GB10051.1. And M grade or P grade should be preferred. 4
Rated load of nutwww.bzxz.net
Under different strength grades and mechanism working levels, the rated load (lifting capacity) borne by each nut should match the hook, and its value should be the same as the lifting capacity of the hook listed in Table 2 in Chapter 4 of GB10051.1. 5 Classification
5.1 Type
5.1.1 The type of nut is mainly divided into the following three types according to the different types of bearings used in the hook device: a.
Installation.
Generally used for hooks with a number of 006 to 1. With a hemispherical raceway surface (under the nut bearing surface), the rolling element can rotate freely--generally used for hooks with a number of 1.6 to 5 with a complete set of bearings and can rotate relatively; generally used for hooks with a number of 6 to 250, with a complete set of bearings, and can rotate relatively. Model indication method
Approved by the Ministry of Machinery Industry of the People's Republic of China on June 16, 1995 and implemented on July 1, 1996
Marking example
JB/T7687.3-95
Strength grade: M, PS, T, V
Hook number: 006~250
Type: A, B, C
Hook number 006, strength grade is M. The hook nut of type A should be marked as: Nut LA006-MJB/T7687.3
Hook number 50. Strength grade is P, The hook nut of type B should be marked as: nut 1.B50-PJB/T7687.3
hook number 160. The strength grade is T, and the hook nut of type C should be marked as: nut LC160-T
JB/T7687.3
5.2 Structural type and size
Structural type of the nut: Type A see Figure], Type B see Figure 2. Type C see Figure 35.2.1
Figure 1 Type A
Anti-loosening pins are equipped with hanging purchases
Assembly and installation holes
[Figure 2 Type B|| tt||Hole for assembly and installation rod
JB/T7687.3--95
Note: t) The size of the positioning plate slot and the hole shall be determined according to JB/T7687.4, and the position of the counter-grid and the screw hole shall be determined during assembly. 2) When the bearing protection in the hook device is integrated, the nut separation is 0.05mm. When a detachable protective cover is used as shown in the left part, the nut height is m, and the contact surface from the bottom of the screw to the upper surface of the bearing is (as shown in the right part). Figure 3C type
5.2.2 The basic dimensions of the nut are shown in Agriculture 1. Hole for assembly and installation rod (size, position and number of nuts for screwing) The quantity is determined according to the needs. For screws with a rotation number of 10 to 100, the recommended hole size is 8 to 20 mm and the number is 2 to 4. 6 Technical requirements
The nuts shall comply with the requirements of the drawings and this standard. 6.1
6.2 The material selected for the nut shall match the material of the hook. The mechanical properties and chemical composition of the material shall comply with the provisions of GB10051.1.
6.3 Forging and heat treatment
6.3.1 The forging and heat treatment of nuts shall comply with the provisions of Articles 5.3.1 and 5.3.2 of JB/T7687.1. 6. 3. 2
The hemispherical raceway surface of type A nut (see Figure 1) shall also be subjected to surface carburizing treatment, and its hardness and carbon depth shall comply with the provisions of Article 6.3 of JB/T7687.2.
6.4 Machining
6.4.1 The dimensional deviation grade of the nut without tolerance shall not be lower than the [
grade in the unmarked tolerance of general tolerance linear dimensions of GB/T1804≤. The unmarked shape and position tolerance shall comply with the relevant provisions of GB/T1184 "Shape and position tolerance unmarked tolerance value", and its straightness and flatness shall comply with the (grade) in Table 1 and Table 2 of this standard. 6.4.2 The maximum allowable value of surface roughness shall comply with the provisions of Table 2. 247
Ordinary thread
Trapezoidal female thread
TY50×6
TY56X6
TY64X8
TY72X×8
TY80×10
TY90X10
TY100×12
2105190
Reference weight.kg
Type A Type B Type C
1.650. 06
Ordinary thread
Chen round thread
TY110×12
TY125X14
TY140×16
TY160×18
TY180X20
TY200×22
TY225×24
TY250×28
TY280X32
TY320×36
Note: CTY is the code for trapezoidal thread.
② Trapezoidal thread is in accordance with the provisions of Appendix A of GB10051.5. The size series of hook No. 200 and 250 are reference values. d
Continued Table 1
Reference weight.kg
Type A Type B
Hemispherical raceway blood in Type A
JB/T7687.3--95
d in Type E and (, trapezoidal round thread, contact surface of upper ring of bearing in Type B and Type C, positioning plate in Type C
Other plus surface
Note: If it is the upper and lower half surfaces and d of the mold, it can be unprocessed. But it should be smooth and flat. 6.4.3
When the nut adopts ordinary thread, its tolerance zone is 6H in GB197. 6.4.4
When the nut adopts trapezoidal round thread .The public recommendation shall be in accordance with GB10051.5. Raμm
The thread shall be matched with the hook and shall be marked. After the nut and the hook are screwed together, they shall form a uniform hook contact. Under no-load conditions, the contact area of ​​the trapezoidal round thread shall not be less than 50%. The anti-loosening pin hole in type B and the nut positioning plate slot in type C shall be processed together with the hook during assembly. 6.4.6
Surface and internal quality
The surface shall be smooth and free of defects such as cracks and folds. There shall be no cracks, white spots or other defects that affect its safety in use. Test method
Chemical analysis sampling of materials shall be in accordance with 4.1 in GB10051.2. .1.1. Composition analysis shall be in accordance with Article 4.1.1.2. 7.1
Tensile test of mechanical properties shall be in accordance with GB228. Impact energy test shall be in accordance with Article 4.1.2.3 of GB10051.2. 7.2
8 Inspection rules
The inspection of nuts shall be carried out by the quality inspection department of the supplier (manufacturer) according to the drawings, technical agreement and this standard. The inspection items and quantity of nuts shall be in accordance with Table 3. 8.2
Mechanical properties
One piece shall be sampled from each batch or tested with a test
Geometric dimensions
Die forging: 10% of the punch shall be inspected,| |tt||But not less than 3 pieces
Free silver parts: 100%
Pre-table quality
Internal quality
When the largest outer diameter of the nut is greater than or equal to
150mm, ultrasonic flaw inspection shall be carried out
Note: The meaning of the determination of each batch is the same as that of 7.2 and 8.3 of JB/T7687.1. The inspection position, sample cutting direction and quantity of each inspection item shall comply with the provisions of the drawings and special technical documents. When ultrasonic inspection is carried out, the position shall be carried out on the height and diameter of the nut. The judgment rules shall be in accordance with 7.4. 8.4
Marking, packaging
The marking shall be fixed and clear at the appropriate position of the screw (generally on the side of the nut). The marking shall be in accordance with 9.1
JB/T7687.2F8.1.
9.2 Packaging shall be in accordance with the relevant provisions of JB/T7687.2 Article 8.2. Additional remarks:
This standard was proposed and managed by the Beijing Hoisting and Conveying Machinery Research Institute of the Ministry of Machinery Industry. This standard was initiated by Taiyuan Lice Machinery Factory. The main drafters of this standard are Zhao Shuihua and Tong Shaoquan. 210
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