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JB/T 7334-2016 English PDF (JBT7334-2016)

JB/T 7334-2016 English PDF (JBT7334-2016)

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JB/T 7334-2016: Hand chain blocks

This standard specifies the basic parameters, technical requirements, test methods, inspection rules, marking, packaging, transportation, storage of hand chain blocks. This standard applies to chain blocks, for general use, which are driven by involute spur gears. This standard does not apply to hand chain blocks, which are used in explosive environments.
JB/T 7334-2016
JB
MECHANICAL INDUSTRY STANDARD
OF THE PEOPLE REPUBLIC OF CHINA
ICS 53.020.99
J 80
Filing No.: 56466-2017
Replacing JB/T 7334-2007
Hand chain blocks
????????????
ISSUED ON: OCTOBER 22, 2016
IMPLEMENTED ON: APRIL 01, 2017
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 4
1 Scope ... 6
2 Normative references ... 6
3 Basic parameters ... 7
4 Technical requirements ... 8
4.1 Temperature of operating environment ... 8
4.2 Performance ... 9
4.3 Main parts ... 11
4.4 Appearance and painting ... 12
4.5 Safety protection ... 12
5 Test method ... 13
5.1 Test load ... 13
5.2 Visual inspection ... 13
5.3 No-load performance test ... 13
5.4 Light load performance test ... 13
5.5 Dynamic load performance test ... 14
5.6 Braking performance test ... 14
5.7 Determination of hand pull ... 14
5.8 Continuous action performance test ... 15
5.9 Limit strength test of whole machine ... 15
5.10 Strength test of whole machine ... 16
5.11 Determination of the minimum distance between two hooks and the lifting height ... 16
5.12 Determination of paint film adhesion ... 16
5.13 Determination of load limit ... 17
6 Inspection rules ... 17
6.1 Inspection classification ... 17
6.2 Exit-factory inspection ... 17
6.3 Type inspection ... 18
7 Marking, packaging, transportation, storage ... 18
7.1 Marking ... 18
7.2 Packaging ... 19
7.3 Transportation and storage ... 19
Hand chain blocks
1 Scope
This standard specifies the basic parameters, technical requirements, test methods, inspection rules, marking, packaging, transportation, storage of hand chain blocks.
This standard applies to chain blocks, for general use, which are driven by involute spur gears.
This standard does not apply to hand chain blocks, which are used in explosive environments.
2 Normative references
The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this document. For undated reference documents, the latest version (including all amendments) is applicable to this document.
GB/T 9286 Paints and varnishes - Cross cut test for films
GB/T 10051.1 Lifting hooks - Part 1: Mechanical properties, lifting capacities, stresses and materials
GB/T 13306 Plates
GB/T 13384 General specifications for packing of mechanical and electrical product
GB/T 20947 Short-link chain for lifting purposes - Grade T (types T DAT and DT) fine-tolerance hoist chain
GB/T 30026 Short link chains for lifting purposes - Grade TH, fine tolerance for manually operated chain blocks
GB/T 30027 Short link chains for lifting purposes - Grade VH, fine tolerance for manually operated chain blocks
JB/T 4207.1 Hooks for manually operated lifting equipment
continuous lifting and lowering operations (one operation consists a cycle of lifting, stop, lowering, stop). After the test of the hand chain block, each part shall not have abnormal phenomena; meanwhile they shall meet the
requirements of 4.2.3 and 4.2.4.
4.2.7 Limit strength of whole machine
By releasing the brake, to make the tail ring limiting device work. The hand chain block shall be able to reliably bear the static tensile load, which is 2.5 times the rated capacity; meanwhile there shall be no damage.
4.2.8 Strength of whole machine
The hand chain block shall be able to reliably support a static tensile load, which is 4 times the rated capacity, for 10 minutes.
4.2.9 Lifting height
The lifting height of the hand chain block shall not be less than the specified value. It should not be greater than 12 m.
4.3 Main parts
4.3.1 Hook
When the rated capacity is not more than 25 t, the hook shall meet the
requirements of JB/T 4207.1. When the rated capacity is more than 25 t, the mechanical properties and materials of the hook shall meet the requirements of GB/T 10051.1. The hook shall be able to rotate 360?? on a horizontal surface. The lower hook shall be equipped with a locking device.
4.3.2 Lifting chain
The lifting chain shall meet the requirements of GB/T 30026 or GB/T 30027, OR meet the requirements of the T-type chain, which is specified in GB/T 20947. 4.3.3 Hand chain
The length of the hand chain should be equal to the lifting height of the hand chain block; however, it is allowed to be less than 200 mm shorter than the lifting height. The mechanical properties shall meet the requirements of Table 7. The connecting ring of the hand chain may be exempted from welding;
however, there shall be no deformation, that affects the use under the pulling force of the ultimate working load.
value of the load limit protection device shall be in the range of 1.3 ~ 1.8 times the rated capacity. At the same time, it shall ensure that the lowering load function of the hand chain block is not affected.
4.5.2 The hand chain block shall be equipped with a tail ring limiting device. It shall meet the requirements of 4.2.7.
5 Test method
5.1 Test load
The test load can adopt the direct loading method by heavy objects, OR
hydraulic pressure OR other loading methods that can generate test loads. When using the heavy object method to load, the allowable deviation of the test load is ??1%. When hydraulic pressure or other loading methods, that can generate test loads, are used, the allowable deviation of the test load is 0 ~ 10%. The heavy object loading method shall be adopted as the basis for
arbitration.
5.2 Visual inspection
The visual inspection shall include whether the specifications and/or status of all important components meet the requirements, such as:
- Hand chain, chain guide, chain stop device, brake;
- All protective devices, including protective covers, tail ring restraints, etc.; - Hook and its connecting parts;
- Lifting chains, lifting sprockets, loose pulley and their fasteners.
5.3 No-load performance test
Hang the hand chain block on the support. Pull the hand chain, by manual method, under no-load condition. Raise and lower the lower hook once,
according to the test lifting height as specified in Table 4.
5.4 Light load performance test
Install the hand chain block on the test bench. According to the test load as specified in 4.2.2 AND the test lifting height as specified in Table 4, operate the measured. The turning angle of the lifting sprocket is converted by the number of loops of the hand chains. Use the electrical measurement method as the basis for arbitration.
5.7.3 Determination by heavy weight method
When using the heavy weight method to determine, first hang the load of the rated capacity, on the hand chain block to be tested. Lift it according to the test lifting height as specified in Table 4. Then adjust the position of the lifting sprocket, so that it is at the position, where the maximum torque is applied from the lifting chain. Use hands to tighten the hand chain on the descending side. Hang the test weight and additional weight, on the hand chain, at the lifting side. The additional weight is 50% of the test weight. The test weight is hanging near the hand chain wheel. The additional weight is hanging at a position 200 mm from the stroke limit surface. Then let go instantly. The two weights will drop at the same time. When the additional weight is in place and stop, the test weight will drop to the lowest point, at a constant speed. At this time, the weight of the test weight is the average hand pull, Fh1. At the position of the lifting sprocket, where the minimum torque is applied from the lifting chain, repeat the above tests, to obtain the average hand pull, Fh2. The average of Fh1 and Fh2 is the average hand pull Fh.
5.8 Continuous action performance test
Place the hand chain block on the tensile test bench. Hang a load of 1.1 times the rated capacity. Drive it manually or by a similar mechanical method. According to the test lifting heights as specified in Table 4, perform 1500 continuous lifting and lowering operations. The working cycle is lifting - stop - lowering - stop. The linear speed of the hand chain shall not exceed 20 m/min. During the test, the load shall not touch the ground. The lifting chain and gears are allowed to be lubricated and cooled forcedly.
5.9 Limit strength test of whole machine
Use a clamp to fix the chain block on the tensile testing machine. The diameter of the clamp, at the connection with the hook, is about 1/3 of the diameter of the hook cavity. Release the brake, to make the tail ring limiting device work. During the test, load slowly and evenly, until it reaches a load of 2.5 times the rated capacity; keep it for 1 min.
For hand chain blocks of multi-row chain type, it is allowed to use the hand chain block of single-row chain type, as an alternative test.
Note: "???" is the item to be inspected. "-" is the item that may be exempted from inspection. 6.3 Type inspection
6.3.1 Type inspection shall be carried out in one of the following situations: - When the old product is subject to trans-plant production, OR the new product is subject to type-finalization and identification;
- Where there are major changes in the structure, materials, processes of the product, which may affect performance;
- No less than once a year after normal production;
- When the production is restored after suspension for more than one year; - Where there is a big difference between the exit-factory inspection results and the last type inspection;
- When the national quality supervision agency puts forward the request for type inspection.
6.3.2 Type inspection items are as shown in Table 8.
7 Marking, packaging, transportation, storage
7.1 Marking
Clear and permanent signs shall be set up at the obvious position of the hand chain block. The signs shall meet the requirements of GB/T 13306. At least the following content shall be marked on the sign:
- Product model and name;
- Basic parameters (including rated capacity and lifting height, etc.); - Exit-factory number and date of manufacture;
- Manufacturer's name;
- Trademark (if any);
- Implemented standard number.

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