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Mechanical Industry Standard of the People's Republic of China
JB2592--91
QL Screw Jack
Published on July 22, 1991
Published by the Ministry of Machinery and Electronics Industry of the People's Republic of China
Implemented on July 1, 1992
Mechanical Industry Standard of the People's Republic of China
QL Screw Jack
1 Subject Content and Scope of Application
JB2592-91
Replaces JB2592-79
This standard specifies the types and basic parameters, technical requirements, inspection rules, as well as marking and packaging of 0.5~100 screw jacks. This standard applies to mechanical screw jacks (hereinafter referred to as screw jacks) for automobiles, bridges, ships and steel structure engineering. Other types of screw jacks should also be used as a reference.
2 Reference standardswwW.bzxz.Net
GB3077
GB9440
GB11352
GB1176
GB1348
GB1804
GB10095
GB11365
GB10089
JB2299
Technical conditions for alloy structural steel
Forgeable iron castings
Carbon structural steel
Casting carbon steel parts for general engineering
Technical conditions for casting copper alloys
Ductile iron castings
Technical conditions for high-quality carbon structural steel
Tolerances and fitsLimit deviations of dimensions without tolerancesPrecision of involute cylindrical gears|| tt||Accuracy of bevel gears and hypoid gears
Accuracy of cylindrical worm gears
Paint colors and safety signs of mining, engineering, lifting and transportation machinery products Types and basic parameters
3.7 Types
3.1.1 The types of jacks are divided into the following categories according to their structures and places of use: 8.
Ordinary type jacks are shown in Figures 1 and 2 (jacks of 50 to 100 t are worm type), and their code letters are QL Ordinary high type screw jacks, whose code is QLG: ordinary low type screw jacks, whose code is QLD; hook type screw jacks are shown in Figure 3, whose code is QLg; scissor type screw jacks are shown in Figure 1, whose code is QLJ, and free-falling screw jacks (equipped with a set of rapid descent mechanisms) are code QLZ. Approved by the Ministry of Machinery and Electronics Industry on July 22, 1991 and implemented on July 1, 1992
Note: The appearance of the ordinary type is the same as that of the ordinary high type and low type. Figure 3
3.1.2 Model indication method
3.1.3 Marking example
JB2592---91
Rated lifting capacity,,
Type characteristic code (no indication for ordinary type); screw jack item.
The mark of ordinary high-type screw jack with rated lifting capacity of 5t is: Jack QLG5JB2592-91
The mark of ordinary screw jack with rated lifting capacity of 10t is: b.
Jack QL10JB2592-91
The mark of scissor-type screw jack with rated lifting capacity of 0.5t is: c.
Jack QLJ0.5JB2592--91
3.2 Basic parameters
The basic parameters of the jack shall comply with the provisions of Table 1. 2
(QLg36）
(QLZ50）
Rated lifting capacity
Minimum height
JB2592—91
Lifting height
Handle force
Handle length
Note, ①The top load capacity of hook screw jack is the rated lifting capacity, and the hook load capacity is half of the rated lifting capacity. Since
②The effective lifting height of scissor screw jack under rated lifting capacity refers to the lifting height from the center position to the highest position; the handle length is the turning radius. The rated lifting capacity refers to the load capacity when the bearing surface is located at more than half of the lifting height. ③The dead weight of the product does not include the handle weight.
③(QLZ50) and (QLg36) in the table are temporarily reserved products. 4Technical requirements
The normal use performance of the product should meet the requirements of Table 1. 4.2 Under the test load (vertical static load) specified in Table 2, the jack shall not produce permanent deformation, cracks or other abnormal banding phenomena in any part.
Rated lifting weight G.
Test load is the percentage of rated lifting weight≤16
JB2592—91
>16~32
>32~100
4.3 Under the test load (vertical dynamic load) of 1.2G, the moving parts of the jack shall work normally and stably and reliably, and any part including the handle shall not produce any abnormal phenomenon that is harmful to the use. 4.4 When the dry jack is raised to the highest state and tilted vertically to the horizontal plane by 6°, it shall remain stable under the lead multiplication static load of the rated lifting weight at the center of the bearing surface, and any part shall not produce permanent deformation or other abnormal phenomena. 4.5 The reliable life of the jack means that when it bears the rated lifting weight, it should be able to reciprocate to the number of times specified in Table 3 within the range of lifting height H (H/2 to the highest position for scissor jacks) (one reciprocating lifting cycle is one time). At this time, all parts must not be damaged, and the jack can still work normally.
Rated lifting weight G
Number of reciprocating cycles
>16~32
>32--100
4.6 The accuracy of bevel gears should not be lower than Grade 10 in GB11365: the accuracy of cylindrical gears should not be lower than Grade 10 in GB10095; the accuracy of worms and worm wheels should not be lower than Grade 9 in GB10089. 4.7 The limit deviation of unnoted tolerance dimensions shall not be less than IT15 in GB1804. 4.8 The main parts of the jack shall preferably be made of materials not less than those specified below: the screw, bevel gear, ratchet, pawl and ratchet shaft of ordinary and hook jacks shall be made of 40Cr in GB3077; a.
cylindrical gears, lifting sleeves and worms shall be made of 45# steel in GB699; c.
the body and ratchet box shall be made of Use KTH330-08 forgeable cast iron in GB9440 or high-strength aluminum alloy with equivalent performance: the worm wheel should be made of QT600-3 ductile iron in GB1348, and the hook jack body should be made of ZG270-500 in GB11352; d. The base should be made of Q235A grade in GB700; the steel nut should be made of ZCuZn25AI6Fe3Mn3 (25-6-3-3 aluminum brass) in GB1176. e.
4.9 The heat treatment hardness of the main parts of the dry jack should comply with the provisions of Table 4. The heat-treated parts shall not have defects such as cracks and overburning. Cold-rolled screws do not need to be heat-treated.
Part name
Heat treatment hardness HRC
4.10 Assembly requirements
Lifting sleeve
4.10.1 All parts must be inspected and qualified before assembly, and purchased parts must have a certificate of conformity. 4.10.2 When assembling interference fit parts, they must be pressed in smoothly without looseness or skewness. 4.10.3 Gears and gears, worms and worm wheels, ratchets and pawls should mesh well. 4.10.4 Gears, bearings and parts prone to wear should be coated with lubricating oil or grease. Ratchet shaft
Bevel gear
4.10.5 For the jack after overall assembly, all operating parts should be flexible and reliable during the action inspection; when operating within the full range of travel, there should be no loose or tight phenomenon.
4.11 Appearance quality
The outer surface of the product shall be sprayed with red paint according to the provisions of JB2299 (if there are special requirements, the supply and demand parties shall negotiate and determine). The paint shall adhere firmly, the coating surface shall be uniform, the color shall be consistent, and there shall be no obvious spots, wrinkles, bubbles and other defects. The exposed processing surface shall be treated with rust prevention.
4.12 Quality assurance
JB259291
Under the condition that the user complies with the storage and use rules, within 18 months from the date of shipment from the manufacturer or 12 months from the date of use by the user, if the product is damaged or cannot be used normally due to poor manufacturing quality, the manufacturer shall be responsible for repairing or replacing parts for the user free of charge. 5 Inspection rules
5.1 Factory inspection
The factory inspection of jacks includes unit-by-unit inspection and sampling inspection. Products can only leave the factory after passing the inspection. The jacks leaving the factory should be accompanied by a product quality certificate.
5.1.1 Inspection of each unit
5.1.1.1 Empty cut test
When checking the action under no-load condition, the operating mechanism of the jack should be flexible and reliable, and there should be no loose or tight phenomenon in the full range of travel. The lifting height H and the minimum height H should meet the requirements of Table 1. The pressing force of the self-falling lowering mechanism of the free-falling jack shall not exceed 30kN. 5.1.1.2 Over-cut test
At room temperature, place the jack on the test equipment and load it according to the requirements of Article 4.3. When lifting one pitch from H/2, the handle of the scissor-type dry jack must be turned more than three times. At this time, all parts of the jack shall not have abnormal phenomena that hinder the use. 5.1.2 Sampling test
Select 0.2% (at least three) of the samples in each batch (or month) of products and test them according to the following items. Among them, if there is one unqualified, it should be doubled for inspection. If more than one unqualified for the first time or there are still unqualified after double inspection, the batch (or month) of products should be inspected one by one.
5.1.2.1 Dynamic load test
Put the jack on a device that can meet the requirements of the dynamic load test at room temperature, and perform a loading inspection according to the requirements of Article 4.3. The bearing surface of the jack is raised from the lowest height H to the lifting height H (scissor jack refers to H/2 to the highest position), and the lifting and lowering cycle is repeated three times. 5.1.2.2 Handle force
Put the jack on a device that can meet the requirements of the dynamic load test at room temperature, and measure the handle length according to the standard. Use a dynamometer to measure the handle force at a distance of 50mm from the handle end under the rated lifting weight. The force should be perpendicular to the handle axis, and the measured results should meet the requirements of Table 1. 5.2 Type inspection
Type inspection should be carried out for any of the following situations:, trial production and identification of new products or old products transferred to the factory: b. After formal production, if there are major changes in structure, materials, and processes that may affect product performance; c
In formal production, in order to verify the stability of product quality, an inspection should be carried out at least once a year; dj
When the product is stopped for a long time for more than one year and then resumes production; when the results of the outgoing inspection are significantly different from the last type inspection e.
1. When the national quality supervision agency proposes a type inspection requirement. In addition to the factory inspection content of Article 5.1, the type inspection items must also inspect the following items. The number of units inspected each time and the inspection of each specification should not be less than three. 5.2.1 Static load test
Put the jack on the test equipment that can add static load, raise the jack to the highest position, and then load it to the test load specified in Table 2. After 3 minutes, no permanent deformation, cracks or other abnormal phenomena shall occur in any part of the dry hall ceiling. 5.2.2 Inclined loading test
Place the dry jack on a test device capable of adding static loads, raise the jack to the highest position at room temperature, and then place an inclined plate with an inclination angle of 6°±0.5° under the jack base. Then add the corresponding rated static load in the plumb direction at the center of the bearing surface of the dry jack. After 3 minutes, the jack should remain stable, and no permanent deformation or other abnormal phenomena should occur in any part. The placement of the scissor dry jack during the test is shown in Figure 5. The inclination direction of the screw and the pad is 45°. The test of the hook jack should be that the load-bearing hook surface is inclined in the inclination direction of the pad. 5
JB2592—91
Jack
5.2.3 Permanent deformation test
After completing the above tests, when the parts are removed for inspection, the load-bearing parts should not have permanent deformation, damage or other abnormal phenomena. 5.2.4 Life test
At room temperature, place the jack on equipment that can meet the requirements of the dynamic load test. The test load is the rated lifting weight. It is reciprocated within the range of the lifting height H (H/2 to the highest position for scissor jacks). The cumulative number of actions of the reciprocating intermittent test shall not be less than the requirements of Table 3. The test results shall meet the requirements of Article 4.5. 6 Product marking, packaging and storage
6.1 Product marking
Each product shall be marked with a permanent mark in an appropriate position. The mark shall be eye-catching and clear, and generally include the following contents: a.
Manufacturer name,
Product name;
Trademark,
Product model or mark:
Manufacture date (or number) or production batch number; main product parameters.
6.2 The packaging of products shall generally comply with the following provisions: a.
The packaging box shall be firm and moisture-proof measures shall be taken inside the box: The product shall be reliably fixed inside the box:
Random documents and attachments: Product certificates, instruction manuals and packing lists shall be packed in moisture-proof bags and placed at a higher position inside the box. c.
A handle shall be attached to each jack.
6.3 Packaging mark
The mark on the packaging box shall be neat and beautiful, and shall not be blurred due to rain erosion and long-term use. The mark content generally includes:, product model, name and quantity
b. Box outline dimensions and gross weight;
Manufacturer and factory date.
6.4 Dry items shall be stored in a well-ventilated, moisture-proof, sun-proof and corrosion-proof warehouse. Additional remarks:
This standard is proposed and managed by the Beijing Hoisting and Transportation Machinery Research Institute of the Ministry of Machinery and Electronics Industry. This standard was drafted by Shanghai Baoshan Jack Factory. The main drafters of this standard are Zhu Kele and Kong Xiao.1 Product Marking
Each product shall be marked with a permanent sign in an appropriate location. The sign shall be eye-catching and clear, and generally include the following contents: a.
Manufacturer name,
Product name;
Trademark,
Product model or mark:
Manufacturing date (or number) or production batch number; Main parameters of the product.
6.2 Product packaging shall generally comply with the following provisions: a.
The packaging box shall be firm and there shall be moisture-proof measures in the box: The product shall be reliably fixed in the box:
Random documents and attachments: Product certificate, instruction manual and packing list shall be packed in moisture-proof bags and placed in a higher position in the box. c.
A handle shall be attached to each jack.
6.3 Packaging Marking
The markings on the packaging box shall be neat and beautiful, and shall not be blurred due to rain erosion and long-term use. The marking content generally includes: product model, name and quantity
b. Box outline size and gross weight;
Manufacturer and factory date.
6.4 Dry items should be stored in a well-ventilated, moisture-proof, sun-proof and corrosion-proof warehouse. Additional remarks:
This standard was proposed and managed by the Beijing Hoisting and Transportation Machinery Research Institute of the Ministry of Machinery and Electronics Industry. This standard was drafted by Shanghai Baoshan Jack Factory. The main drafters of this standard are Zhu Kele and Kong Xiao. 61 Product Marking
Each product shall be marked with a permanent sign in an appropriate location. The sign shall be eye-catching and clear, and generally include the following contents: a.
Manufacturer name,
Product name;
Trademark,
Product model or mark:
Manufacturing date (or number) or production batch number; Main parameters of the product.
6.2 Product packaging shall generally comply with the following provisions: a.
The packaging box shall be firm and there shall be moisture-proof measures in the box: The product shall be reliably fixed in the box:
Random documents and attachments: Product certificate, instruction manual and packing list shall be packed in moisture-proof bags and placed in a higher position in the box. c.
A handle shall be attached to each jack.
6.3 Packaging Marking
The markings on the packaging box shall be neat and beautiful, and shall not be blurred due to rain erosion and long-term use. The marking content generally includes: product model, name and quantity
b. Box outline size and gross weight;
Manufacturer and factory date.
6.4 Dry items should be stored in a well-ventilated, moisture-proof, sun-proof and corrosion-proof warehouse. Additional remarks:
This standard was proposed and managed by the Beijing Hoisting and Transportation Machinery Research Institute of the Ministry of Machinery and Electronics Industry. This standard was drafted by Shanghai Baoshan Jack Factory. The main drafters of this standard are Zhu Kele and Kong Xiao. 6
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