Spacing-adjustable automatic resistance measuring device for electric smelting pipe fittings

Abstract

The utility model relates to a distance-adjustable electric melting pipe fitting automatic resistance measuring device which is formed by combining a set overall structure fixing frame, a sliding table air cylinder fixing plate, a lifting sliding table air cylinder, an adjusting and measuring mechanism, a position graduated scale, a resistance tester and the like. The adjusting and measuring mechanism is fixed on a movable sliding table of the lifting sliding table air cylinder through an adjusting and measuring mechanism overall frame and is driven by the lifting sliding table air cylinder to move up and down, and the automatic resistance measuring device for the electric smelting pipe fitting with the adjustable distance and high practicability is formed. The utility model has the advantages of novel design and reasonable conception, mainly has the functions of automatically measuring the resistance value of the electric melting pipe fitting and adjusting to be compatible with the electric melting pipe fittings with different specifications, and simultaneously has the advantages of simple structure, cost saving, extremely low dependence on the environment and convenience in operation.

Description

Technical Field

[0001] The utility model relates to the technical field of the assembly and packaging of PE electrofusion pipe fittings, and specifically, it is an automatic resistance measuring device for electrofusion pipe fittings with adjustable spacing. Background Art

[0002] During the assembly and packaging process of PE electrofusion pipe fittings, after the electrode heads are assembled, it is necessary to measure and screen the resistance value of the resistance wire between the two electrode columns to prevent unqualified products from flowing into the market and affecting the normal progress of on-site construction. Currently, the resistance measurement is carried out manually, which has low efficiency, high labor intensity, and is prone to fatigue during manual measurement, still resulting in unqualified products flowing into the market and affecting the product quality. In addition, the existing manual measurement tools cannot be compatible with the measurement requirements of electrofusion pipe fittings of different specifications and cannot be compatible with the measurement requirements of electrofusion pipe fittings with electrode heads of different spacings. Content of the Utility Model

[0003] The utility model provides an automatic resistance measuring device for electrofusion pipe fittings with adjustable spacing, aiming to make up for the defects of low efficiency, high labor intensity, and being prone to fatigue during manual measurement of the resistance of PE electrofusion pipe fittings, still resulting in unqualified products flowing into the market and affecting the product quality, as well as the problem that the existing measurement tools cannot be compatible with the measurement requirements of electrofusion pipe fittings of different specifications and electrofusion pipe fittings with electrode heads of different spacings.

[0004] The purpose of the utility model is achieved through the following technical solutions:

[0005] An automatic resistance measuring device for electrofusion pipe fittings with adjustable spacing includes a general structure fixing frame, a lifting slide cylinder, a slide cylinder fixing plate, an adjusting and measuring mechanism, and a resistance tester; the slide cylinder fixing plate is fixed on the general structure fixing frame, the lifting slide cylinder is fixed on the slide cylinder fixing plate, the lifting slide cylinder is fixed on the general structure fixing frame through the slide cylinder fixing plate, the adjusting and measuring structure is arranged on the lifting slide cylinder, the resistance tester is arranged on the top of the general structure fixing frame, the adjusting and measuring mechanism has a left measuring head assembly and a right measuring head assembly with adjustable spacing, and the adjusting and measuring mechanism is electrically connected to the resistance tester for measuring the resistance value of the electrofusion pipe fittings.

[0006] A further technical solution is that the slide cylinder fixing plate is provided with a waist-shaped hole for adjusting the up and down height, the slide cylinder fixing plate is connected and fixed to the general structure fixing frame by screws, and the lifting slide cylinder is connected and fixed to the slide cylinder fixing plate by screws.

[0007] Further technical solution: The adjustment and measurement structure includes the overall frame of the adjustment and measurement mechanism. The overall frame of the adjustment and measurement mechanism is fixedly connected to the lifting slide cylinder. A cavity is provided at the lower part of the overall frame of the adjustment and measurement mechanism. Left and right side plates are respectively arranged on the left and right sides of the cavity. A left pedestal bearing is arranged on the outer side of the left side plate, and a right pedestal bearing is arranged on the outer side of the right side plate. A left-right through-threaded adjustment lead screw is arranged in the cavity. Both ends of the left-right threaded adjustment lead screw pass through the left and right pedestal bearings. Adjustment knobs are connected to both ends of the left-right threaded adjustment lead screw, and the adjustment knobs are used to control the rotation of the left-right threaded adjustment lead screw.

[0008] Further technical solution: A left adjustment movable block and a right adjustment movable block are movably arranged in the cavity; the head contours of the left adjustment movable block and the right adjustment movable block are consistent with the cavity. The left-right threaded adjustment lead screw is divided into left and right sections. The left section uses a right-hand thread, and the right section uses a left-hand thread. The left adjustment movable block is sleeved on the left section of the right-hand thread, and the right adjustment movable block is sleeved on the right section of the left-hand thread. The left adjustment movable block and the right adjustment movable block can move left and right as the left-right threaded adjustment lead screw rotates.

[0009] Further technical solution: A long strip waist-shaped hole is opened at the front end of the overall frame of the adjustment and measurement mechanism and a position scale is provided. The adjustment and measurement structure further includes a scale indicating needle and a locking and fixing handle. The scale indicating needle passes through the long strip waist-shaped hole and is fixedly connected to the left adjustment movable block. The locking and fixing handle passes through the long strip waist-shaped hole and is fixedly connected to the right adjustment movable block for positioning and fixing the right adjustment movable block.

[0010] Further technical solution: Left and right measurement head assemblies are respectively threadedly connected below the left adjustment movable block and the right adjustment movable block for measuring the resistance value of the electrofusion pipe fitting.

[0011] Further technical solution: The left and right measurement head assemblies have the same structure, including a measurement sleeve and a movable measurement head. A measurement connection wire is arranged inside the measurement sleeve. One end of the measurement connection wire is fixed to the movable measurement head through a connection wire compression bolt, and the other end is electrically connected to a resistance tester. A buffer return spring is also sleeved outside the measurement connection wire inside the measurement sleeve.

[0012] Compared with the prior art, the beneficial effects of the present utility model are:

[0013] In the present utility model, the mounting holes of the sliding table cylinder fixing plate are designed as waist-shaped holes, which have a certain margin for up and down adjustment and can accommodate the measurement requirements of different specifications of pipe fittings. The adjustment blocks on the left and right sides are designed to be adjustable left and right, which can accommodate the measurement requirements of PE electrofusion pipe fittings with different electrode head spacings. The combination of the position scale and the scale indicating needle makes the left and right adjustment more intuitive. The PE electrofusion pipe fittings of the required specifications can be quickly adjusted and switched in place according to the scale value, improving the switching efficiency and reducing the startup time. The locking fixing handle can lock the entire adjustment device after the adjustment and switching are in place, preventing the device from loosening and shifting during use and affecting the measurement stability of the device. The movable measuring head is made of copper material, which has good electrical conductivity and improves the reliability of resistance measurement. The buffer return spring provides a buffer return force for the movable measuring head, so that the movable measuring head will not collide hard with the electrode head of the electrofusion pipe fitting during resistance measurement, resulting in damage to both, and improving the measurement stability.

[0014] Its main working mode is that the set overall structure fixing frame, sliding table cylinder fixing plate, lifting sliding table cylinder, adjustment and measurement mechanism, position scale, resistance tester, etc. are combined together. The adjustment and measurement mechanism is fixed on the movable slide of the lifting sliding table cylinder through the overall frame of the adjustment and measurement mechanism, and is driven by the lifting sliding table cylinder to move up and down, forming a practical adjustable-spacing electrofusion pipe fitting automatic resistance measurement device.

[0015] Advantages of the present utility model: novel design, reasonable concept, mainly having the functions of automatically measuring the resistance value of electrofusion pipe fittings and being able to adjust and accommodate different specifications of electrofusion pipe fittings. At the same time, the structure is simple, cost-saving, has extremely low dependence on the environment, and is convenient to operate. Description of the Drawings

[0016] Figure 1 General structure schematic diagram of the device of the present utility model;

[0017] Figure 2 Front view of the general structure of the device of the present utility model;

[0018] Figure 3 Detail drawing of the adjustment and measurement mechanism of the device of the present utility model;

[0019] Figure 4 Disassembly drawing of the adjustment and measurement mechanism of the device of the present utility model;

[0020] Figure 5 Detail drawing of the measuring head assembly of the device of the present utility model;

[0021] Figure 6 Disassembly drawing of the measuring head assembly of the device of the present utility model;

[0022] Figure 7Structural diagram of the electrofusion fitting of the device of the present utility model.

[0023] The component numbers in the attached drawings are: 1, resistance tester; 2, fixed plate of the sliding table cylinder; 3, overall structure fixing frame; 4, electrofusion fitting; 5, adjustment and measurement mechanism; 6, overall frame of the adjustment and measurement mechanism; 7, lifting sliding table cylinder; 8, left side sealing plate; 9, left pedestal bearing; 10, left - and - right - threaded adjustment lead screw; 11, left - hand measurement head assembly; 12, scale indicating needle; 13, right - hand measurement head assembly; 14, locking and fixing handle; 15, position scale; 16, adjustment knob; 17, left - hand adjustment movable block; 18, right - hand adjustment movable block; 19, right side sealing plate; 20, right pedestal bearing; 21, measurement sleeve; 22, movable measurement head; 23, buffer reset spring; 24, measurement connecting wire; 25, connecting wire compression bolt; 26, left - hand electrode head of the electrofusion fitting; 27, right - hand electrode head of the electrofusion fitting. Detailed implementation manners

[0024] To make the objectives, technical solutions and advantages of the present utility model clearer, the technical solutions of the present utility model will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other implementation manners obtained by those of ordinary skill in the art without making creative efforts shall fall within the scope protected by the present utility model. Embodiment 1

[0025] An automatic resistance measuring device for an electrofusion fitting with adjustable spacing mainly includes an overall structure fixing frame 3, a lifting sliding table cylinder 7, a fixed plate of the sliding table cylinder 2, an adjustment and measurement mechanism 5 and a resistance tester 1. The lifting sliding table cylinder 7 is fixed on the overall structure fixing frame 3 through the fixed plate of the sliding table cylinder 2. The adjustment and measurement structure 5 is arranged on the lifting sliding table cylinder 7. The resistance tester 1 is arranged on the top of the overall structure fixing frame 3. The adjustment and measurement mechanism 5 has a left - hand measurement head assembly 11 and a right - hand measurement head assembly 13 with adjustable spacing, and the adjustment and measurement mechanism 5 is electrically connected to the resistance tester 1 for measuring the resistance value of the electrofusion fitting 4.

[0026] The overall structure fixing frame 3 is made of thickened steel pipes and steel plates by cutting, welding and drilling. There is a square hole on the top for wire routing, and there are enclosures around the top. The resistance tester 1 is placed on the top of the overall structure fixing frame 3 and is limited by the enclosures.

[0027] The fixed plate of the sliding table cylinder 2 is made of thickened steel plates by cutting and drilling. There are 4 waist - shaped holes on the upper side for adjusting the up - and - down height. The fixed plate of the sliding table cylinder 2 is connected and fixed to the overall structure fixing frame 3 through 4 internal hexagonal screws, and the lifting sliding table cylinder 7 is connected and fixed to the fixed plate of the sliding table cylinder 2 through 4 internal hexagonal screws.

[0028] The described adjustment and measurement structure 5 includes an overall framework 6 of the adjustment and measurement mechanism. The overall framework 6 of the adjustment and measurement mechanism is made by cutting, punching, and grinding a thickened steel block. A square hole is opened at its top for wire routing, and a long strip waist-shaped hole is opened at the front. The overall framework 6 of the adjustment and measurement mechanism is fixedly connected to the movable slide of the lifting slide cylinder 7 through 4 hexagon socket head cap screws. A cavity is provided at the lower part of the overall framework 6 of the adjustment and measurement mechanism. A left side sealing plate 8 and a right side sealing plate 19 are respectively provided on the left and right sides of the cavity. A left side pedestal bearing 9 is provided on the outer side of the left side sealing plate 8, and a right side pedestal bearing 20 is provided on the outer side of the right side sealing plate 19. A left-right through threaded adjustment lead screw 10 is provided in the cavity. Both ends of the threaded adjustment lead screw 10 pass through the left side pedestal bearing 9 and the right side pedestal bearing 20. Adjustment knobs 16 are connected to both ends of the threaded adjustment lead screw 10. The adjustment knobs 16 are used to control the rotation of the threaded adjustment lead screw 10.

[0029] The threaded adjustment lead screw 10 is made by cutting, grinding, and subjecting a thickened steel bar to conditioning treatment. Its left section uses a right-handed thread, and its right section uses a left-handed thread design. A left side adjustment movable block 17 and a right side adjustment movable block 18 are movably arranged in the cavity; the left side adjustment movable block 17 and the right side adjustment movable block 18 are made by cutting, punching, and grinding a thickened steel block. The head contour thereof is consistent with the inner contour of the overall framework 6 of the adjustment and measurement mechanism, and its size is slightly smaller than the inner size of the overall framework 6 of the adjustment and measurement mechanism, so that the left side adjustment movable block 17 and the right side adjustment movable block 18 can move left and right inside the overall framework 6 of the adjustment and measurement mechanism.

[0030] A small hole is opened at the top of the left side adjustment movable block 17 and the right side adjustment movable block 18. The small hole avoids the upper threaded hole and communicates with the bottom for wire routing. The left side adjustment movable block 17 is arranged inside the overall framework 6 of the adjustment and measurement mechanism and is threadedly connected to the right-handed thread section of the threaded adjustment lead screw 10. The right side adjustment movable block 18 is arranged inside the overall framework 6 of the adjustment and measurement mechanism and is threadedly connected to the left-handed thread section of the threaded adjustment lead screw 10. The left side adjustment movable block 17 and the right side adjustment movable block 18 can move left and right along with the rotation of the threaded adjustment lead screw 10.

[0031] The left sealing plate 8 and the right sealing plate 19 are formed by cutting and punching thickened steel plates. The left sealing plate 8 is connected and fixed to the overall frame 6 of the adjustment and measurement mechanism through 2 hexagon socket head cap screws. The right sealing plate 19 is connected and fixed to the overall frame 6 of the adjustment and measurement mechanism through 2 hexagon socket head cap screws. The left pedestal bearing 9 is sleeved on the left end of the left and right thread adjusting lead screw 10 and is connected to it by interference fit and is connected and fixed to the left sealing plate 8 through 2 hexagon socket head cap screws. The right pedestal bearing 20 is sleeved on the right end of the left and right thread adjusting lead screw 10 and is connected to it by interference fit and is connected and fixed to the right sealing plate 19 through 2 hexagon socket head cap screws. The adjustment knob 16 is connected to the left and right thread adjusting lead screw 10 by thread and is fixed tightly by 1 set screw.

[0032] A long strip waist-shaped hole is provided at the front end of the overall frame 6 of the adjustment and measurement mechanism, and a position scale 15 is provided. The position scale 15 is adhesively connected to the overall frame 6 of the adjustment and measurement mechanism through double-sided tape. The adjustment and measurement structure 5 further includes a scale indicating needle 12 and a locking and fixing handle 14. The scale indicating needle 12 is connected to the left adjustment movable block 17 by thread. The locking and fixing handle 14 is connected to the right adjustment movable block 18 by thread and is used to position and fix the right adjustment movable block 18.

[0033] A left measuring head assembly 11 and a right measuring head assembly 13 are respectively connected to the lower sides of the left adjustment movable block 17 and the right adjustment movable block 18 by thread and are used to measure the resistance value between the electrode heads of the electrofusion pipe fitting 4.

[0034] The left measuring head assembly 11 is connected and fixed to the left adjustment movable block 17 by thread. The right measuring head assembly 13 is connected and fixed to the right adjustment movable block 18 by thread. The left measuring head assembly 11 and the right measuring head assembly 13 have the same structure, including a measuring sleeve 21 and a movable measuring head 22. A measuring connecting wire 24 is arranged inside the measuring sleeve 21; the movable measuring head 22 is formed by cutting, punching and polishing a copper rod, and the measuring sleeve 21 is formed by cutting, punching and polishing a thickened steel rod. The measuring connecting wire 24 is tightly connected and fixed to the movable measuring head 22 by a connecting wire pressing bolt 25. The measuring connecting wire 24 enters the left and right adjustment movable blocks 17 and the right adjustment movable block 18 along the measuring sleeve 21 and comes out from the round holes at the tops of the left adjustment movable block 17 and the right adjustment movable block 18, and then is connected to the resistance tester 1 along the square hole at the top of the overall frame 6 of the adjustment and measurement mechanism and the square hole at the top of the overall structure fixing frame 3. A buffer return spring 23 is further sleeved outside the measuring connecting wire 24 inside the measuring sleeve 21. The buffer return spring 23 is inserted into the measuring sleeve 21 and is arranged between the movable measuring head 22 and the adjustment movable block to provide buffering and return force for the movable measuring head 22.

[0035] The main working mode of the device of the present utility model is that a set of overall structure fixing frame, slide table cylinder fixing plate, lifting slide table cylinder, adjusting and measuring mechanism, position scale, resistance tester, etc. are combined together. The adjusting and measuring mechanism is fixed on the movable slide table of the lifting slide table cylinder through the overall frame of the adjusting and measuring mechanism, and is driven by the lifting slide table cylinder to move up and down, forming an automatic resistance measuring device for electrofusion fittings with strong practicability and adjustable spacing.

[0036] The device of the present utility model is novel in design and reasonable in conception, and mainly has the functions of automatically measuring the resistance value of electrofusion fittings and being able to adjust and be compatible with electrofusion fittings of different specifications. At the same time, it has a simple structure, saves costs, has extremely low dependence on the environment, and is convenient to operate.

[0037] The specific implementation process of the utility model device in the production process is as follows: First, fix the whole device on the electrofusion fitting assembly and packaging line through the overall structure fixing frame 3, then adjust the up and down height of the slide table cylinder fixing plate 2 according to the specification of the electrofusion fitting 4 to be measured, and rotate the adjusting knob 16 to adjust the left and right positions of the left adjusting movable block 17 and the right adjusting movable block 18. During the adjustment process, observe the indication value of the scale indicating needle 12 corresponding to the electrofusion fitting 4 of this specification. After the adjustment is in place, lock the locking fixing handle 14 to prevent the adjustment mechanism from shifting during operation. Then start the device. After the front-end conveying tooling clamps and conveys the electrofusion fitting 4 in place, the lifting slide table cylinder 7 moves down, driving the overall frame 6 of the adjusting and measuring mechanism and the mechanism above to move down, and the left measuring head assembly 11 and the right measuring head assembly 13 move down accordingly. After moving down, the movable measuring head 22 of the left measuring head assembly 11 contacts the left electrode head 26 of the electrofusion fitting, and the movable measuring head 22 of the right measuring head assembly 13 contacts the right electrode head 27 of the electrofusion fitting. During this process, the buffer reset spring 23 provides buffering for the measurement of the movable measuring head 22 to prevent damage to both due to hard contact with the electrode head. Then the resistance value between the left electrode head 26 and the right electrode head 27 of the electrofusion fitting is measured by the resistance tester 1 through the movable measuring heads 22 of the left measuring head assembly 11 and the right measuring head assembly 13 and the measuring connection wire 24. Finally, the lifting slide table cylinder 7 returns to its original position, driving the overall frame 6 of the measuring mechanism and the mechanism above to move up, and the movable measuring heads 22 of the left measuring head assembly 11 and the right measuring head assembly 13 bounce out and return to their original positions under the reset action of the buffer reset spring 23. When the resistance value measured by the resistance tester 1 does not meet the requirements, the rejection mechanism at the rear end of the device rejects the electrofusion fitting. When the measured resistance value meets the requirements, the electrofusion fitting flows into the rear end for the next bagging and packaging process. The device then waits for the arrival of the next electrofusion fitting for the next resistance value measurement. The device operation is completed.

[0038] Advantages of the present utility model: novel design and reasonable concept. It mainly has the functions of automatically measuring the resistance value of electrofusion fittings and being able to adjust and be compatible with electrofusion fittings of different specifications. At the same time, it has a simple structure, saves costs, has extremely low dependence on the environment, and is convenient to operate.

[0039] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as within the protection scope of the present utility model.

Claims

1. An automatic resistance measuring device for electric fusion pipes with adjustable spacing, characterized in that: The invention comprises an overall structure fixing frame (3), a lifting slide cylinder (7), a slide cylinder fixing plate (2), an adjustment and measuring mechanism (5) and a resistance tester (1); the lifting slide cylinder (7) is fixed to the overall structure fixing frame (3) through the slide cylinder fixing plate (2); the adjustment and measuring mechanism is arranged on the lifting slide cylinder (7); the resistance tester (1) is arranged on the top of the overall structure fixing frame (3); the adjustment and measuring mechanism comprises a left measuring head assembly (11) and a right measuring head assembly (13) with adjustable spacing; the adjustment and measuring mechanism is electrically connected to the resistance tester (1) and is used to measure the resistance value of the electric fusion pipe fitting (4).

2. The automatic resistance measuring device for electric fusion pipes with adjustable spacing as claimed in claim 1, characterized in that: The slide cylinder fixing plate (2) is provided with waist-shaped holes for adjusting the upper and lower heights; the slide cylinder fixing plate (2) is connected and fixed to the overall structure fixing frame (3) by screws; and the lifting slide cylinder (7) is connected and fixed to the slide cylinder fixing plate (2) by screws.

3. The automatic resistance measuring device for electric fusion pipes with adjustable spacing as claimed in claim 1, characterized in that: The adjusting and measuring mechanism (5) comprises an adjusting and measuring mechanism overall frame (6), the adjusting and measuring mechanism overall frame (6) being fixedly connected to the lifting slide cylinder (7), a cavity being arranged at the lower part of the adjusting and measuring mechanism overall frame (6), a left side sealing plate (8) and a right side sealing plate (19) being arranged on the left and right sides of the cavity respectively, a left side bearing (9) being arranged on the outer side of the left side sealing plate (8), a right side bearing (20) being arranged on the outer side of the right side sealing plate (19), a positive and negative thread adjusting screw (10) being arranged to pass through the left and right sides of the cavity, two ends of the positive and negative thread adjusting screw (10) being arranged to pass through the left and right side bearing (9) and the right and negative thread adjusting screw (20), two ends of the positive and negative thread adjusting screw (10) being connected to adjusting knobs (16), the adjusting knobs (16) being used to adjust the rotation of the positive and negative thread adjusting screw (10).

4. The automatic resistance measuring device for electric fusion pipes with adjustable spacing as claimed in claim 3, characterized in that: A left-side adjusting movable block (17) and a right-side adjusting movable block (18) are movably arranged in the cavity; the head contours of the left-side adjusting movable block (17) and the right-side adjusting movable block (18) are consistent with the cavity; the positive and negative thread adjusting screw (10) is divided into left and right sections, the left section adopts positive threads, and the right section adopts negative threads; the left-side adjusting movable block (17) is sleeved on the positive threads of the left section, and the right-side adjusting movable block (18) is sleeved on the negative threads of the right section; the left-side adjusting movable block (17) and the right-side adjusting movable block (18) can move left and right as the positive and negative thread adjusting screw (10) rotates.

5. The automatic resistance measuring device for electric fusion pipes with adjustable spacing as claimed in claim 4, characterized in that: The front end of the overall frame (6) of the adjusting and measuring mechanism is provided with a long waist-shaped hole and a position scale (15). The adjusting and measuring mechanism (5) further comprises a scale indicator needle (12) and a locking and fixing handle (14). The scale indicator needle (12) passes through the long waist-shaped hole and is fixedly connected to the left adjusting movable block (17). The locking and fixing handle (14) passes through the long waist-shaped hole and is fixedly connected to the right adjusting movable block (18) for positioning and fixing the right adjusting movable block (18).

6. The automatic resistance measuring device for electric fusion pipes with adjustable spacing according to claim 4 is characterized in that: A left measuring head assembly (11) and a right measuring head assembly (13) are respectively threadedly connected below the left adjusting movable block (17) and the right adjusting movable block (18) to measure the resistance value between the electrode heads of the electric fusion pipe fitting (4).

7. The automatic resistance measuring device for electric fusion pipes with adjustable spacing according to claim 6 is characterized in that: The left measuring head assembly (11) and the right measuring head assembly (13) have the same structure, comprising a measuring sleeve (21) and a movable measuring head (22) connected to the measuring sleeve (21); a measuring connecting wire (24) is arranged inside the measuring sleeve (21); one end of the measuring connecting wire (24) is fixed to the movable measuring head (22) via a connecting wire clamping bolt (25); the other end is electrically connected to the resistance tester (1); and a buffer reset spring (23) is also sleeved on the outside of the measuring connecting wire (24) inside the measuring sleeve (21).

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