Some standard content:
Mechanical Industry Standard of the People's Republic of China
Chain lever hoist
Subject content and scope of application
JB/T7335-94
Replaces JB 3928.2-85
JB 3928.1-85
This standard specifies the basic parameters, technical requirements, test methods, inspection rules, marking and packaging of chain lever hoists. This standard is mainly applicable to chain lever hoists (hereinafter referred to as lever hoists) with a rated lifting capacity of 0.5 to 9t for general use and with involute cylindrical gear transmission (hereinafter referred to as lever hoists). Chain lever hoists of other structural forms should also be used as a reference. 2 Reference standards
GB4829 General acceptance rules for short link chains for lifting
GB5802 Short link chains for lifting - T (8) grade calibration chains for hoists and other lifting equipment GB/T13384 General technical conditions for packaging of electromechanical products JB4207 Hooks for manual lifting equipment
ZBJ80004 Hook locking device for manual lifting equipment 3 Basic parameters
3.1 The basic parameters of the lever hoist shall comply with the provisions of Figure 1 and Table 1.
Approved by the Ministry of Machinery Industry of the People's Republic of China on July 18, 1994 and implemented on July 1, 1995
Rated lifting capacity G.
Standard lifting height H
Minimum distance between two hooks Hmia
JB/T 7335--94
Note: ①H in the table refers to the distance between the lowest and highest working positions of the lower hook. 1. 5
②Hmin in the table refers to the distance between the inner edges of the upper and lower hook cavities when the lower hook rises to the limit working position. 3.2 Product marking
3.2.1 Model representation method
Total lifting height, m
-Lifting weight, t
Product code
3.2.2 Marking example
The marking of a chain lever hoist with a lifting weight of 5t and a lifting height of 1.5m is: Lever hoist HSH5-1.5JB/T7335--944 Technical requirements
4.1 Performance
4.1.1 No-load action
When the lever hoist is in no-load action, each mechanism should operate flexibly without blocking or loose and tight phenomena. Disengage the clutch device, and the hand-operated electric chain should be light and flexible.
4.1.2 Dynamic load performance
When the hand-operated hoist is subjected to the dynamic load test, it should be able to withstand the test load specified in Table 2, and lift and lower it once according to the test lifting height specified in Table 3. At the same time, the following requirements must be met: a.
The gear transmission should be smooth;
The meshing of the lifting chain and the lifting sprocket, and the reversing pawl and the reversing ratchet should be good; the brake should work reliably;
There is no twisting or jamming of the lifting chain during lifting and lowering; the handle moves smoothly, and the hand pull force does not change greatly. Table 2
Rated lifting capacity G,
Test load
Number of lifting chain rows
Test lifting height/m
4.1.3 Braking performance
The braking performance of the brake shall be sensitive and reliable. Tests shall be carried out in sequence according to the test loads specified in Table 4. The weight shall be lowered to a height equivalent to the lifting sprocket rotating for more than one circle. After standing for 1 hour, the weight shall not fall by itself. Table 4
Rated lifting capacity G,
Test load
4.1.4 Overall efficiency
When the lever hoist is lifting the rated load, the overall efficiency is determined by formula (1), and its calculated value shall comply with the provisions of Table 5. Qe
+|×100
=|Fhin
Where: n—efficiency of the whole machine, %;
Q. —Force kN at rated lifting capacity; n——number of lifting chain rows;
i-total transmission ratio of the whole machine;
Fh—actually measured average hand pull force, kN;
K—additional value of transmission efficiency when overcoming static friction resistance torque 0.04. Table 5
Rated lifting capacity Gn,t
Rate, %
Note: The efficiency of 2t hand lever hoist with double chain should not be less than 64%. 4.1.5 Continuous action performance
(1))
The continuous action performance of the lever hoist is evaluated by testing. According to the test load specified in Table 2, the lever hoist is continuously raised and lowered to the number of actions specified in Table 6 according to the test lifting height specified in Table 3 (one cycle of raising, stopping, lowering and stopping is one time). After the test, the lever hoist must still meet the requirements of Articles 4.1.2 and 4.1.3.
Rated lifting capacity G,
Continuous number of actions, times
4.1.6 Static load performance
The lever hoist must be able to support a static tensile load of 4 times the rated lifting capacity. 4.2 Main components
4.2.1 The hook shall comply with the provisions of JB4207. The hook must be equipped with a hook mouth locking device that complies with the provisions of ZBJ80004. The hook shall be able to rotate 360° on the horizontal plane.
4.2.2 The lifting chain shall comply with the provisions of GB4829 and shall not be lower than the T (8) grade in GB5802. 4.2.3 The lifting chain tail ring limiter must be installed at the unloaded end of the lifting chain. 4.2.4 The lifting sprocket and the cruiser shall be smoothly engaged with the chain, and the lifting sprocket and the cruiser shall be heat treated. 4.2.5 The chain guide and chain retaining structure shall ensure the correct engagement of the chain and the sprocket, and shall prevent the chain from falling out of the sprocket ring groove. 4.2.6 The brake device must have reliable performance and a protective cover shall be provided to prevent dust from entering. 4.3 Appearance quality
4.3.1 All parts of the lever hoist shall be well made and shall not have defects such as scratches and burrs that affect the appearance quality. 4.3.2 The exposed unprocessed surface of the lever hoist shall be painted, and the coating shall be evenly coated with uniform color and shall not have stains, marks, cracks, pores, shrinkage, shedding and roughness defects.
JB/T 7335-94
4.3.3 The exposed processed surface of the lever hoist shall be blued or phosphated or coated with anti-rust grease, and shall not have rust. 5 Test method
5.1 No-load action inspection
Hang the lever hoist on the bracket, pull the handle and pull the reversing melon under no-load condition, so that the hook rises and falls once, and its stroke shall not be less than the provisions of Table 3. Disconnect the clutch device and use a manual chain. The test results shall meet the requirements of Article 4.1.1. 5.2 Dynamic load test
Place the lever hoist on the test bench and drive it manually or by similar mechanical means according to the test load specified in Table 2 and the test lifting height specified in Table 3. However, the lifting speed of the chain should not be greater than 0.45m/min. The test results should meet the requirements of Article 4.1.2. 5.3 Determination of overall efficiencywwW.bzxz.Net
On the chain lever hoist test bench, the lever force can be measured by the sensor method or the yard measurement method, and then converted into overall efficiency according to formula (1). The sensor measurement method must be calibrated. The basic yard measurement method is: rotate the dial block to the rising position, and when it is lifted by 0.3m under the load of the rated lifting weight, place the handle horizontally, hang a yard at the end of the handle (record the effective length), and gradually increase the yard until the handle starts to move. The weight of this yard is the measured value of the lever force when overcoming the static friction resistance torque. The hand pull force should be measured twice, the first time when the flat ring of the lifting chain is in a horizontal position, and the second time when the vertical ring of the lifting chain is in a horizontal position. The average of the two measurements is taken as the hand pull force to overcome the static friction resistance torque. 5.4 Braking performance test
According to Table 4, load the test in sequence with 3 different test loads. During the test, hang the hand winch on the test bench, hang the test code on the lower hook, and after lifting 300mm, use manual method to lower the load to a height equivalent to more than one rotation of the lifting chain wheel. Check the braking performance of the brake by hand feeling and self-test. The test results should meet the requirements of Article 4.1.3.
5.5 Continuous action performance test
The test is carried out on the test bench. The test load, test lifting height and lifting chain linear speed are the same as the dynamic load test. The test is driven manually or mechanically, and the working cycle is lifting-stopping-lowering-stopping. During the maneuvering test, the power-on duration of the electrical equipment is 40%. Continuous action is automatically controlled and counted. The load does not touch the ground during descent, and the lifting chain and gears are allowed to be lubricated. The test results should meet the requirements of Article 4.1.5.
5.6 Static load test
Clamp the lever hoist on the universal testing machine with a special ring clamp, and rotate the handle block to the rising position. The diameter of the connection between the special ring clamp and the hook is about one-third of the hook cavity diameter. When clamping, the flat ring of the lifting chain should be in a horizontal position on the lifting sprocket, and then slowly and evenly load until the test load and requirements specified in Article 4.1.6 are reached, and maintained for 1 minute. 5.7 The determination of the breaking force and total ultimate elongation of the lifting chain shall comply with the provisions of Chapter 6 of GB5802. 5.8 Determination of the deviation of the pitch of the N-ring of the lifting chain. On the universal material testing machine, randomly select a lifting chain sample with an appropriate number of rings and install it into the fixture and apply a tension of 5% of the chain verification force to tighten the chain segment, as shown in Figure 2. Use a vernier caliper to measure the values of Lout, 2d, and 2d., and measure three times at the same position to get the average value. Then calculate according to the following formula, and its value should comply with the provisions of Article 4.3.2.2 of GB5802. L=lout
2di+2dz
AL-L-NP
Where: LN total length of ring pitch. mm:
P-nominal value of single ring pitch·mm;
AL---limit deviation of N-ring pitch, mm;
N~--number of randomly sampled chain links (its value is equal to 2 times the number of lifting sprocket grooves + 1). 194
（2）
（3）
JB/T733594
5.9 Deformation measurement and overload test of hook mouth. It shall comply with the provisions of Chapter 5 of JB4207. 5.10 Determination of minimum distance between two hooks and standard lifting height. Add appropriate load to the lever hoist on the test bench to put it in working state, lift the lower hook to the upper limit working position, and measure the distance value Hmin between the inner edges of the upper and lower hook cavities. Then, lower the lower hook to the lower limit working position, and measure the distance value Hmx between the inner edges of the upper and lower hook cavities (see Figure 1).
The standard lifting height is obtained by formula (4):
H-Hmax-Hmin
6 Inspection rules
6.1 Type inspection
6.1.1 Type inspection should generally be carried out in any of the following situations: a.
Trial production and identification of new products or old products transferred to the factory for production; after formal production, if there are major changes in structure, materials, and processes that may affect product performance; at least once a year for normally produced products; when a product is discontinued for more than half a year and production is resumed; when the factory inspection results are significantly different from the last type inspection; when the national quality supervision agency proposes a type inspection requirement. Type inspection items are as follows:
Appearance quality inspection, visual inspection in accordance with Article 4.3; no-load action inspection, in accordance with Article 5.1; basic parameter determination, in accordance with Article 5.10; dynamic load test, in accordance with Article 5.2;
machine efficiency determination, in accordance with Article 5.3; braking performance test, in accordance with Article 5.4; continuous action performance test, in accordance with Article 5.5; static load test, in accordance with Article 5.6:
determination of the breaking force and total ultimate elongation of the lifting chain, in accordance with Article 5.7; determination of the N-link pitch deviation of the lifting chain, in accordance with Article 5.8; hook hook deformation determination and overload test, in accordance with Article 5.9. 6.2 Factory inspection
6.2.1 Each lever hoist must be inspected and qualified by the manufacturer before it can leave the factory, and a product certificate will be issued. 6.2.2 The items for factory inspection shall be inspected in accordance with the requirements of items a, b and d in the type inspection items. (4)
Marking, packaging
JB/T7335-94
Each lever hoist shall have a product label that is not easily lost. The label shall indicate: 7.1
Manufacturer name,
Product name;
Trademark;
Product model or mark;
Main parameters of the product:
Manufacturing date (or number) or production batch number. 7.2 Packaging
When the lever hoist leaves the factory, it must be properly packaged, and the packaging shall comply with the requirements of GB/T13384. 7.3 The following documents shall be attached to the products leaving the factory: Product certificate;
Product use and maintenance instructions.
Additional Notes:
This standard was proposed and managed by the Beijing Hoisting and Conveying Machinery Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Beijing Hoisting and Conveying Machinery Research Institute. The main drafter of this standard is Liang Jianai.
This standard is equivalent to the Japanese standard JIS B8819--1990 "Chain Hand Hoist". 196
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