A device for jack drop follow-up test

Abstract

The present invention relates to a device for jack descending follow-up test, comprising a bracket, a weight-variable pressure block arranged on the bracket, a lifting unit for controlling the weight change of the pressure block, a position sensor for sensing the position of the pressure block, and a controller connected to a distance sensor for controlling the movement of the lifting unit. Compared with the prior art, the present invention can make the weight of the pressure block adjustable to match the rated load-bearing capacity of different jacks through the arrangement of multiple stacked counterweight blocks and the lifting unit; and the entire test process is controlled by the controller, so the risk to personnel is low and the result is highly accurate.

Description

Technical Field

[0001] The invention relates to the field of detection technology, and in particular to a device used for jack descent follow-up testing. Background Art

[0002] A jack is a light and small lifting device that uses a rigid lifting piece as a working device to lift heavy objects through a small stroke of the top support or bottom claw. Jacks are mainly used in factories, mines, transportation and other departments for vehicle repair and other lifting and supporting work. Its structure is light and strong, flexible and reliable, and can be carried and operated by one person. There are several types of car jacks, such as pneumatic jacks, electric jacks, hydraulic jacks and mechanical jacks. The quality of this product in the Chinese market is uneven. In 2017, the Quality Supervision Bureau of the Shanghai Industrial and Commercial Bureau conducted market inspections and quality sampling on various jacks on the market. After testing, a large number of batches had safety problems and quality risks. At the same time, jacks have a large number of exports to the European market with excellent cost performance, but the European market, especially the German and French quality supervision agencies, are very strict. In 2017, a large number of containers of car jacks were found to be unqualified, and the manufacturer's products were claimed and returned, resulting in serious losses. The corresponding test standard for jacks is EN1494:2000+A1:2008. This European standard was adopted by the European Committee for Standardization (CEN) on October 18, 2000, and includes the revised version adopted by the European Committee for Standardization (CEN) on November 8, 2008. One of the important test clauses is the B.1 type test, which requires that when carrying the rated load, the average speed of the jack's descent should not exceed 0.15 m / s; its significance is greater than when the jack is under the load of the car, the owner or maintenance personnel releases the pressure relief valve, and the load descent speed is very dangerous if it is too fast. The average descent speed is required to be no more than 0.15 m / s. A large number of jacks that have been claimed and returned in the German market are judged as failed by the German testing agency in this test, resulting in losses of tens of millions of RMB. Regarding this test, domestic testing agencies currently do not have testing equipment, so the development of testing equipment based on this clause is of great significance for controlling product quality. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a device for jack descent following test with a wide range of applications and a high degree of automation.

[0004] The object of the present invention can be achieved through the following technical scheme: a device for jack descent follow-up test, which includes a bracket, a variable weight pressure block arranged on the bracket, a lifting unit for controlling the weight change of the pressure block, a position sensor for sensing the position of the pressure block, and a controller connected to the distance measuring sensor for controlling the movement of the lifting unit.

[0005] The pressure block includes multiple stacked counterweight blocks, and a through rectangular groove is provided at the center of the bottom of each counterweight block. Multiple stacked counterweight blocks are provided, and the number of counterweight blocks is selected according to the rated lifting range of the jack to adjust the weight of the pressure block; the groove is provided to facilitate the lifting unit to lift the pressure block located at the top.

[0006] The weight of all the counterweight blocks is the same, which is 100-200 kg, and the number of the counterweight blocks is 5-15.

[0007] The lifting unit includes a moving plate vertically mounted on a bracket, a retractable plug shaft fixedly mounted on the moving plate, a lifting motor for driving the moving plate to move, and a retractable motor for driving the plug shaft to retract. The lifting motor and the retractable motor are connected to a controller, and the plug shaft matches the rectangular groove. When the plug shaft is inserted into the groove, the lifting motor drives the moving plate to rise, and the counterweight block above is lifted as a whole. The total weight of the remaining counterweight block is the load-bearing capacity of the jack.

[0008] There are two position sensors, one above and one below, fixed on the bracket, and the distance between the two position sensors in the vertical direction is 10 to 20 cm. When the jack descends, the top surface of the counterweight block at the uppermost end will pass through the two position sensors in sequence, and the position sensor transmits the signal to the controller. The controller calculates the average descending speed of the jack according to the time when the two signals are received and the distance between the two position sensors.

[0009] The controller is provided with an encoder for timing.

[0010] The controller is a single chip microcomputer.

[0011] Compared with the prior art, the beneficial effects of the present invention are embodied in the following aspects:

[0012] (1) By stacking multiple counterweights and setting a lifting unit, the weight of the pressure block can be adjusted to match the rated load of different jacks;

[0013] (2) The entire test process is controlled by a controller, which reduces the risk to personnel and increases the accuracy of the results. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the present invention.

[0015] Among them, 1 is a bracket, 2 is a support plate, 3 is a counterweight block, 4 is a groove, 5 is a lifting motor, 6 is a telescopic motor, 7 is a moving plate, 8 is a plug shaft, 9 is a position sensor, and 10 is a jack to be tested. DETAILED DESCRIPTION

[0016] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0017] Example 1

[0018] A device for jack drop follow-up test, the structure of which is as follows Figure 1 As shown, the device includes a bracket 1, a weight-variable pressure block arranged on the bracket 1, a lifting unit for controlling the weight change of the pressure block, a position sensor 9 for sensing the position of the pressure block, and a single-chip microcomputer connected to the distance measuring sensor for controlling the movement of the lifting unit, wherein an encoder for timing is provided in the single-chip microcomputer

[0019] The pressing block comprises a total of 7 stacked counterweight blocks 3, and a through rectangular groove 4 is provided at the center of the bottom of each counterweight block 3. The mass of each counterweight block 3 is 200 kg, and the total mass of the pressing block is 1.4 t.

[0020] The lifting unit includes a moving plate 7 vertically movable on the bracket 1, a retractable plug shaft 8 fixedly arranged on the moving plate 7, a lifting motor 5 for driving the moving plate 7 to move, and a telescopic motor 6 for driving the plug shaft 8 to retract. The lifting motor 5 and the telescopic motor 6 are connected to the controller, and the plug shaft 8 matches the rectangular groove 4. When the plug shaft 8 is inserted into the groove 4, the lifting motor 5 drives the moving plate 7 to rise, and the counterweight block 3 above is lifted as a whole. The total weight of the remaining counterweight block 3 is the load-bearing capacity of the jack.

[0021] Two position sensors 9 are provided, fixed on the bracket 1 one above and one below, and the distance between the two position sensors 9 in the vertical direction is 15 cm.

[0022] The working principle of this device is as follows:

[0023] When not testing, 7 counterweights 3 are stacked on the support plate 2 of the bracket 1. When a jack with a rated load of 1.2t needs to be tested, the jack 10 to be tested is placed at the bottom of the counterweight 3, and the single-chip microcomputer controls the telescopic motor 6 to drive the plug-in shaft 8 to retract, and then controls the lifting motor 5 to drive the moving plate 7 to descend until the plug-in shaft 8 is at the same height as the groove of the top counterweight 3, and then the single-chip microcomputer controls the telescopic motor 6 to drive the plug-in shaft 8 to extend and insert into the groove, and then controls the lifting motor 5 to drive the moving plate 7 to rise. Operate the jack 10 to be tested to lift the remaining 6 counterweights 3 until the upper surface of the topmost counterweight 3 among the 6 counterweights 3 is higher than the position sensor 9 located on the upper side, then release the pressure relief valve of the jack 10 to be tested, and the counterweights 3 will descend together with the jack 10 to be tested. The top surface of the counterweight 3 located at the top will pass through the two position sensors 9 in sequence. The position sensor 9 transmits the signal to the controller, and the controller calculates the average descending speed of the jack according to the time when the two signals are received and the distance between the two position sensors 9.

Claims

1. A device for jack drop follow-up test, characterized in that: The device comprises a support, a weight-variable pressing block arranged on the support, a lifting unit for controlling the weight change of the pressing block, a position sensor for sensing the position of the pressing block, and a controller connected to the distance measuring sensor for controlling the movement of the lifting unit; The pressing block comprises a plurality of stacked counterweight blocks, and a through rectangular groove is provided at the center of the bottom of each counterweight block; The lifting unit comprises a moving plate vertically arranged on the bracket, a retractable plug shaft fixedly arranged on the moving plate, a lifting motor for driving the moving plate to move, and a retractable motor for driving the plug shaft to retract, the lifting motor and the retractable motor are connected to the controller, and the plug shaft matches the rectangular groove; The controller is provided with an encoder for timing.

2. The device for jack drop following test according to claim 1, characterized in that: The weight of all the counterweight blocks is the same, which is 100-200 kg, and the number of the counterweight blocks is 5-15.

3. The device for jack drop following test according to claim 1, characterized in that: There are two position sensors, which are fixed on the bracket one above and one below, and the distance between the two position sensors in the vertical direction is 10-20 cm.

4. A device for jack descent following test according to any one of claims 1 to 3, characterized in that: The controller is a single chip microcomputer.

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