A verticality testing device for prefabricated building construction acceptance
By designing a verticality testing device that combines multi-angle adjustable support rods and pipe fittings, the problems of slow measurement speed, inability to adjust to multiple angles, and inconvenient storage of traditional testing devices have been solved. This has enabled efficient and accurate verticality testing, adapting to the varied working conditions of prefabricated building construction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENZHEN SPORTS CENT OPERATION MANAGEMENT CO LTD
- Filing Date
- 2025-07-23
- Publication Date
- 2026-05-26
AI Technical Summary
Traditional verticality testing devices in prefabricated buildings suffer from problems such as slow measurement speed, inability to adjust to multiple angles, high cost, and inconvenient storage, making it difficult to meet the high-efficiency testing needs of construction sites.
A verticality detection device comprising a connecting block, a support rod, and a pipe fitting was designed. The support rod is adjustable at multiple angles. By combining the connecting block and the support rod, rapid detection and convenient storage can be achieved. The support rod is equipped with a pipe fitting to adjust the height and length, and has the functions of multi-angle adjustment and rapid storage.
It improves the accuracy and efficiency of testing, meets the high-efficiency testing needs of prefabricated building construction, has flexibility and practicality, adapts to complex working conditions, and reduces equipment costs.
Smart Images

Figure CN224285922U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of building construction testing technology, specifically a verticality testing device for the acceptance of prefabricated building construction. Background Technology
[0002] With the rapid development of prefabricated buildings, modular construction has placed higher demands on on-site installation accuracy. Precise detection of the verticality between walls and floors, and between components, is a crucial step in ensuring construction quality. Traditional verticality testing relies heavily on tools such as levels, plumb lines, or laser rangefinders. While these methods can achieve basic measurement functions, they still have significant limitations in practical applications. For example, the traditional plumb line method is greatly affected by ambient airflow, resulting in poor measurement stability; while laser rangefinders offer high accuracy, they are expensive and require professional operation, making them unsuitable for the complex and ever-changing conditions of construction sites. Furthermore, existing testing devices are mostly fixed structures, bulky, and inconvenient to store, failing to meet the needs of efficient construction and transportation in prefabricated buildings, thus exhibiting certain shortcomings. Utility Model Content
[0003] To address the shortcomings of existing technologies, this utility model provides a verticality testing device for prefabricated building construction acceptance, which has the advantages of multi-angle adjustment, rapid measurement and convenient storage. It solves the problems of slow measurement speed, inability to adjust multiple angles, high cost and inability to be quickly and conveniently stored of current level instruments, plumb lines or laser rangefinders.
[0004] To achieve the above objectives, this utility model provides the following technical solution: a verticality testing device for prefabricated building construction acceptance, comprising a connecting block, support rods, and pipe fittings. Two sets of support rods are movably connected to the side of the connecting block in a vertical direction. The connecting block is right-angled, with its right-angled side fitting between the wall and the ground. The two sets of support rods installed on the side can be folded and unfolded vertically by swinging. When folded, it is easy to store and transport. When unfolded into a right-angled shape, it can fit against both the ground and the wall, thereby detecting the verticality between the wall and the ground during prefabricated building construction acceptance.
[0005] Two connecting slots are provided on the side of the connecting block.
[0006] A rotating roller is provided at one end of the support rod, and the rotating roller is rotatably connected in the connecting groove. At the same time, an adjustment knob is provided at both ends of the rotating roller, and the adjustment knob passes through the side of the connecting block. Through the rotating roller, the support rod rotates in the corresponding connecting groove to realize the angle adjustment of the support rod.
[0007] Angle marks are set on the side of the connecting block. The angle marks are located on the side of the adjustment knob. At the same time, the adjustment knob is set with a mark point. The mark point corresponds to the corresponding angle mark according to the rotation angle of the adjustment knob. When the support rod rotates, it drives the adjustment knob to rotate at the same time, so that the mark point corresponds to the corresponding angle value on the angle mark, thereby realizing the detection of the vertical angle of the wall and the ground.
[0008] On the support rod, there is a mounting cylinder along its length. A pipe is movably connected inside the mounting cylinder. The length of the pipe matches the length inside the mounting cylinder. The pipe can extend the measured height and length by changing its displacement back and forth inside the mounting cylinder. At the same time, it is supported on the opposite wall to fix the position of the entire device.
[0009] The fitting consists of a support rod and an extension rod, which are movably connected inside the mounting cylinder. One end of the support rod is movably connected to a retaining element, which is used to fix the angle of the support rod and the extension rod and to fold them. The support rod and the extension rod are of the same length, so that they can be completely retracted into the mounting cylinder when folded. When unfolded, the support rod and the extension rod are straight. By adjusting the length of the extension rod, it can be supported on walls of different heights or lengths, thereby improving the stability of the measurement.
[0010] When using this prefabricated building construction acceptance verticality testing device, two sets of support rods are unfolded, with one set of support rods attached to the ground and the other set to the wall. Simultaneously, a connecting block is attached to the corner of the wall and ground. By pulling the pipe fitting from inside the mounting cylinder outwards, the sliding knob moves from the tail end to the front end within the stabilizing groove. Rotating the retaining rod ensures its front end is tightly against the side of the support rod. Then, swinging the extension rod straightens it to the support rod. Rotating the adjusting ring moves the sleeve rod from inside the sleeve outwards until the sleeve rod in one set of support rods abuts against the wall, and the sleeve rod in the other set abuts against the roof, thus fixing the device in place. The vertical tilt of the wall or ground can then be detected by observing the values corresponding to the markings on the adjusting knobs of the corresponding support rods and the angle markings.
[0011] As a further improvement to the above solution, the side of the connecting block is provided with two sets of positioning components. The positioning components include an adjustment groove opened on the side of the connecting block, an adjustment block slidably connected in the adjustment groove, a connecting rod fixed on the side of the adjustment block, a positioning button fixed at one end of the connecting rod, and one end of the positioning button passing through the connecting groove and fitting against the side of the rotating roller.
[0012] With the above technical solution, the two sets of positioning components are located on two perpendicular surfaces of the connecting block, which are used to fix the angle of inclination of the corresponding support rod.
[0013] As a further improvement to the above solution, a tension spring is fixed between the inner side of the adjustment groove and the adjustment block.
[0014] Through the above technical solution, the tension spring is used to push the adjusting block upward, so that the tooth profile on the positioning button engages with the tooth profile on the rotating roller.
[0015] As a further improvement to the above solution, a stabilizing groove is provided on the side of the mounting cylinder, and a sliding button is slidably connected in the stabilizing groove. One end of the sliding button is fixed to the side of the support rod, while the other end is fixed with a limit button, which fits against the outer edge of the stabilizing groove.
[0016] With the above technical solution, when the support rod moves up and down, the sliding button slides up and down in the stable groove, thereby improving the stability of the support rod displacement. At the same time, because the diameter of the limiting button is larger than the width of the stable groove, the limiting button slides against the edge of the stable groove, thereby preventing the sliding button from detaching from the stable groove and causing the pipe fitting to detach from the installation cylinder.
[0017] As a further improvement to the above solution, one end of the support rod is threadedly connected to a retaining rod, one end of which passes through a stabilizing groove and fits against the side of the support rod.
[0018] The above technical solution allows the retaining rod to be rotated in either the forward or reverse direction, causing its front end to either detach from or adhere to the side of the support rod. When detached, the support rod can move within the mounting cylinder, while when adhered, it effectively fixes the position of the support rod.
[0019] As a further improvement to the above solution, the extension rod consists of a sleeve, a rod, and an adjusting ring. The rod is movably sleeved at both ends of the sleeve, and the adjusting ring is rotatably connected to both ends of the sleeve. The adjusting ring is threaded to the side of the rod.
[0020] The above technical solution allows for the adjustment and setting of the overall length of the extension rod by rotating the adjusting ring in both directions, enabling the sleeve rod to extend and retract within the sleeve.
[0021] As a further improvement to the above solution, one end of the sleeve rod is fixed with a connecting button one, and one end of the support rod is rotatably connected to a connecting button two. Both connecting button one and connecting button two have mounting buttons on their sides.
[0022] The retaining element includes a mounting plate that is rotatably connected to the sides of connector one and connector two.
[0023] By using the above technical solution, the angle between the extension rod and the support rod can be adjusted by rotating the connecting button on the side of the mounting plate, thereby achieving two forms: folded storage and straight unfolding.
[0024] As a further improvement to the above solution, multiple notches are provided at equal intervals at both ends of the mounting plate.
[0025] The retaining element also includes a spring button that is movably sleeved on the side of the first and second connecting buttons. The side of the spring button is provided with a protrusion that is movably connected in the recess.
[0026] With the above technical solution, the spacing between the multiple notches opened at both ends of the mounting plate is the same. When the support rod and extension rod are perpendicular to the mounting plate, the support rod and extension rod are in a folded state. At this time, the protrusion is inserted into one of the corresponding notches on the side of the mounting plate. When the support rod and extension rod are straight to the mounting plate, the support rod and extension rod are in an unfolded state. At this time, the protrusion is inserted into other corresponding notches on the side of the mounting plate, thereby fixing the angle after deformation.
[0027] Compared with the prior art, this utility model provides a verticality detection device for the construction and acceptance of prefabricated buildings, which has the following beneficial effects:
[0028] 1. This verticality testing device for prefabricated building construction acceptance uses two sets of angle-adjustable support rods installed vertically on the side of the connecting block. The two sets of support rods are respectively attached to the wall and the ground, and the connecting block is attached to the corner where the wall and the ground meet. By observing the value of the angle mark corresponding to the adjustment knob on the rotating roller of the support rod, the vertical angle between the wall and the ground can be quickly detected, which effectively improves the accuracy and efficiency of the test.
[0029] 2. This verticality testing device for prefabricated building construction acceptance uses a pipe fitting inside a support rod. The pipe fitting is secured by a fixing component installed between the support rod and the extension rod, allowing for swinging, folding, and straight unfolding. This enables rapid deployment for testing and storage. It can also test the flatness of walls and floors. Furthermore, by adjusting the length of the extension rod, it can be used on walls or floors of different heights and lengths, further improving the device's practicality and flexibility. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the overall pipe fitting storage structure of the device of this utility model;
[0031] Figure 2 This is a schematic diagram of the side structure of the connecting block of this utility model;
[0032] Figure 3 This is a schematic diagram of the overall tubular structure of the device of this utility model;
[0033] Figure 4 This is a schematic diagram of the overall structure of the connecting rod and positioning button of this utility model;
[0034] Figure 5 This utility model Figure 1 Schematic diagram of the structure at point A in the middle;
[0035] Figure 6 This utility model Figure 3 Schematic diagram of the structure at point B.
[0036] The attached diagram lists the components represented by each number as follows:
[0037] 1. Connecting block; 11. Connecting groove; 12. Positioning component; 101. Adjusting groove; 102. Adjusting block; 103. Connecting rod; 104. Positioning button; 105. Tension spring; 106. Angle mark;
[0038] 2. Support rod; 201. Mounting cylinder; 202. Stabilizing slide; 203. Slide button; 204. Limit button; 205. Rotating roller; 206. Adjusting button; 207. Marking point; 208. Fixing rod;
[0039] 3. Pipe fittings; 31. Support rod; 311. Connecting button two; 32. Extension rod; 321. Sleeve; 322. Sleeve rod; 323. Adjusting ring; 324. Connecting button one; 325. Mounting button; 33. Fixing component; 331. Mounting plate; 332. Notch; 333. Spring button; 334. Protrusion. Detailed Implementation
[0040] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model. Example 1
[0041] Please see Figure 1-6 As shown, the verticality testing device for prefabricated building construction acceptance proposed in this embodiment includes a connecting block 1, support rods 2, and pipe fittings 3. Two sets of support rods 2 are movably connected to the side of the connecting block 1 in a vertical direction. The connecting block 1 is right-angled, with the right-angled side fitting between the wall and the ground. The two sets of support rods 2 installed on the side can be folded and unfolded vertically by swinging. When folded, it is easy to store and transport. When unfolded into a right-angled shape, it can fit against both the ground and the wall at the same time, so as to detect the verticality between the wall and the ground during the construction acceptance of prefabricated buildings.
[0042] Two connecting slots 11 are provided on the side of the connecting block 1.
[0043] One end of the support rod 2 is provided with a rotating roller 205, which is rotatably connected in the connecting groove 11. At the same time, both ends of the rotating roller 205 are provided with adjustment knobs 206, which pass through the side of the connecting block 1. Through the rotating roller, the support rod 2 rotates in the corresponding connecting groove 11 via the rotating roller 205, thereby realizing the angle adjustment of the support rod 2.
[0044] An angle mark 106 is provided on the side of the connecting block 1. The angle mark 106 is located on the side of the adjusting knob 206. At the same time, the adjusting knob 206 is provided with a mark point 207. The mark point 207 corresponds to the corresponding angle mark 106 according to the rotation angle of the adjusting knob 206. The angle mark 106 is specifically an angle value, which is set in a ring shape at equal intervals on the edge of the circular hole through which the adjusting knob 206 passes on the side of the connecting block 1. When the support rod 2 rotates, it drives the adjusting knob 206 to rotate at the same time, so that the mark point 207 corresponds to the corresponding angle value on the angle mark 106, thereby realizing the detection of the vertical angle of the wall and the ground.
[0045] On the support rod 2, an installation cylinder 201 is provided along its length direction. A pipe fitting 3 is movably connected inside the installation cylinder 201. The length of the pipe fitting 3 matches the length inside the installation cylinder 201. The pipe fitting 3 can extend the measured height and length by changing its displacement back and forth inside the installation cylinder 201. At the same time, it is supported on the opposite wall to fix the position of the entire device.
[0046] The fitting 3 consists of a support rod 31 and an extension rod 32. The support rod 31 and the extension rod 32 are movably connected inside the mounting cylinder 201, and one end is movably connected to a retaining member 33. The retaining member 33 is used to fix the angle of the support rod 31 and the extension rod 32 and to fold them. The support rod 31 and the extension rod 32 are of the same length, so that when folded, they can be completely retracted into the mounting cylinder 201. When unfolded, the support rod 31 and the extension rod 32 are straight. By adjusting the length of the extension rod 32, it can be supported on walls of different heights or lengths, thereby improving the stability of the measurement.
[0047] The working principle of the verticality testing device for prefabricated building construction acceptance proposed in this embodiment is as follows: During use, two sets of support rods 2 are unfolded, with one set of support rods 2 attached to the ground and the other set attached to the wall. Simultaneously, the connecting block 1 is attached to the corner of the wall and ground. By pulling the pipe fitting 3 from inside the mounting cylinder 201 outwards, the sliding button 203 moves from its tail end to its front end within the stabilizing groove 202. Furthermore, by rotating the retaining rod 208, the front end of the retaining rod 208 is tightly pressed against the side of the support rod 31. At this time, by swinging the extension rod 32, the extension rod 32 and the support rod 31 are made to be straight. By rotating the adjustment ring 323, the sleeve rod 322 moves outward from the sleeve 321 until the sleeve rod 322 in one set of support rods 2 abuts against the wall and the sleeve rod 322 in the other set of support rods 2 abuts against the roof, thus fixing the device. At this time, the vertical tilt of the wall or the ground can be detected by observing the value corresponding to the mark point 207 and the angle mark 106 on the adjustment knob 206 in the corresponding support rod 2.
[0048] Furthermore, the side of the connecting block 1 is provided with two sets of positioning members 12. The positioning member 12 includes an adjustment groove 101 opened on the side of the connecting block 1. An adjustment block 102 is slidably connected in the adjustment groove 101. A connecting rod 103 is fixed on the side of the adjustment block 102. A positioning button 104 is fixed at one end of the connecting rod 103. One end of the positioning button 104 passes through the connecting groove 11 and is attached to the side of the rotating roller 205.
[0049] More specifically, the two sets of positioning elements 12 are located on two perpendicular surfaces of the connecting block 1, and are used to fix the angle of inclination of the corresponding support rod 2.
[0050] It should be further explained that by moving the adjusting block 102 to the upper part within the adjusting groove 101, the connecting rod 103 drives the positioning button 104 to move upward, so that the top of the positioning button 104 is in contact with the corresponding position on the side of the rotating roller 205, thereby achieving the function of fixing the support rod 2 after the angle is adjusted.
[0051] In addition, both the positioning button 104 and the side of the rotating roller 205 are provided with toothed patterns. The positioning button 104 is attached to the side of the rotating roller 205, so that the toothed patterns are engaged, thereby fixing the angle of the support rod 2.
[0052] Furthermore, a tension spring 105 is fixed between the inner side of the adjusting groove 101 and the adjusting block 102.
[0053] More specifically, the tension spring 105 is used to push the adjusting block 102 upward, so that the tooth profile on the positioning button 104 engages with the tooth profile on the rotating roller 205.
[0054] Furthermore, a stabilizing groove 202 is provided on the side of the mounting cylinder 201, and a sliding button 203 is slidably connected in the stabilizing groove 202. One end of the sliding button 203 is fixed to the side of the support rod 31, and the other end is fixed to a limit button 204, which fits against the outer edge of the stabilizing groove 202.
[0055] More specifically, when the support rod 31 moves up and down, the sliding button 203 slides up and down within the stabilizing groove 202, thereby improving the stability of the displacement of the support rod 31. At the same time, because the diameter of the limiting button 204 is larger than the width of the stabilizing groove 202, the limiting button 204 slides against the edge of the stabilizing groove 202, thereby preventing the sliding button 203 from detaching from the stabilizing groove 202 and causing the pipe fitting 3 to detach from the mounting cylinder 201.
[0056] Furthermore, one end of the support rod 2 is threadedly connected to a retaining rod 208, one end of which passes through a stabilizing groove 202 and fits against the side of the support rod 31.
[0057] More specifically, by rotating the retaining rod 208 in the forward or reverse direction, the front end of the retaining rod 208 can be disengaged from or attached to the side of the support rod 31. When disengaged, the support rod 31 can be displaced within the mounting cylinder 201, while when attached, it can fix the position of the support rod 31. Example 2
[0058] Please see Figure 3 and Figures 5-6 As shown, the verticality testing device for prefabricated building construction acceptance proposed in this embodiment, based on the first embodiment, further includes an extension rod 32 composed of a sleeve 321, a sleeve rod 322 and an adjusting ring 323. The sleeve rod 322 is movably sleeved at both ends of the sleeve 321, and the adjusting ring 323 is rotatably connected to both ends of the sleeve 321. The adjusting ring 323 is threadedly connected to the side of the sleeve rod 322.
[0059] More specifically, by rotating the adjusting ring 323 in both clockwise and counterclockwise directions, the sleeve 322 can be moved telescopically within the sleeve 321, thereby adjusting and setting the overall length of the extension rod 32.
[0060] In addition, by extending the extension rod 32, horizontal and vertical support can be achieved, and the flatness of the ground and wall surfaces can also be detected.
[0061] Furthermore, one end of the sleeve rod 322 is fixed with a connecting button 324, and one end of the support rod 31 is rotatably connected to a connecting button 311. Both the connecting button 324 and the connecting button 311 have mounting buttons 325 on their sides.
[0062] The retaining member 33 includes a mounting plate 331 that is rotatably connected to the side of the connecting button 1 324 and the connecting button 2 311.
[0063] More specifically, by rotating the connecting button 324 and the connecting button 311 on the side of the mounting plate 331, the angle between the extension rod 32 and the support rod 31 can be adjusted, thereby achieving two forms: folded storage and straight unfolding.
[0064] Furthermore, multiple notches 332 are equidistantly provided at both ends of the mounting plate 331.
[0065] The retaining member 33 also includes a spring button 333 that is movably sleeved on the side of the first connecting button 324 and the second connecting button 311. The side of the spring button 333 is provided with a protrusion 334, which is movably connected in the recess 332.
[0066] More specifically, the multiple notches 332 opened at both ends of the mounting plate 331 are spaced at the same distance. When the support rod 31 and the extension rod 32 are perpendicular to the mounting plate 331, the support rod 31 and the extension rod 32 are in a folded state. At this time, the protrusion 334 is inserted into one of the corresponding notches 332 on the side of the mounting plate 331. When the support rod 31 and the extension rod 32 are straight to the mounting plate 331, the support rod 31 and the extension rod 32 are in an unfolded state. At this time, the protrusion 334 is inserted into the other corresponding notches 332 on the side of the mounting plate 331, so as to fix the angle after deformation.
[0067] It should be further explained that the spring button 333 consists of a spring and a round button. Under the push of the spring, the round button moves forward and becomes flush with the mounting plate 331, so that the protrusion 334 is inserted into the corresponding recess 332.
[0068] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A verticality testing device for prefabricated building construction acceptance, comprising a connecting block (1), a support rod (2), and a pipe fitting (3), characterized in that, The side of the connecting block (1) is movably connected to two sets of support rods (2) in a vertical direction; The side of the connecting block (1) has two connecting grooves (11). One end of the support rod (2) is provided with a rotating roller (205), which is rotatably connected in the connecting groove (11). At the same time, both ends of the rotating roller (205) are provided with adjustment knobs (206), which pass through the side of the connecting block (1). An angle mark (106) is provided on the side of the connecting block (1). The angle mark (106) is located on the side of the adjustment knob (206). At the same time, a mark point (207) is provided on the adjustment knob (206). The mark point (207) corresponds to the corresponding angle mark (106) according to the rotation angle of the adjustment knob (206). The support rod (2) is provided with an installation cylinder (201) along its length, and a pipe fitting (3) is movably connected inside the installation cylinder (201); The fitting (3) consists of a support rod (31) and an extension rod (32). The support rod (31) and the extension rod (32) are movably connected inside the mounting cylinder (201), and one end is movably connected to a retaining member (33). The retaining member (33) is used to fix and fold the angle adjusted by the support rod (31) and the extension rod (32).
2. The verticality testing device for prefabricated building construction acceptance according to claim 1, characterized in that: The side of the connecting block (1) is provided with two sets of positioning parts (12). The positioning parts (12) include an adjustment groove (101) opened on the side of the connecting block (1), an adjustment block (102) is slidably connected in the adjustment groove (101), a connecting rod (103) is fixed on the side of the adjustment block (102), and a positioning button (104) is fixed at one end of the connecting rod (103). One end of the positioning button (104) passes through the connecting groove (11) and is attached to the side of the rotating roller (205).
3. The verticality testing device for prefabricated building construction acceptance according to claim 2, characterized in that: A tension spring (105) is fixed between the inner side of the adjustment groove (101) and the adjustment block (102).
4. The verticality testing device for prefabricated building construction acceptance according to claim 1, characterized in that: The mounting cylinder (201) has a stabilizing groove (202) on its side. A sliding button (203) is slidably connected in the stabilizing groove (202). One end of the sliding button (203) is fixed to the side of the support rod (31), and the other end is fixed with a limit button (204). The limit button (204) fits against the outer edge of the stabilizing groove (202).
5. A verticality testing device for prefabricated building construction acceptance according to claim 1, characterized in that: One end of the support rod (2) is threadedly connected to a retaining rod (208), one end of which passes through a stabilizing groove (202) and fits against the side of the support rod (31).
6. The verticality testing device for prefabricated building construction acceptance according to claim 1, characterized in that: The extension rod (32) consists of a sleeve (321), a rod (322) and an adjusting ring (323). The rod (322) is movably sleeved at both ends of the sleeve (321), and the adjusting ring (323) is rotatably connected at both ends of the sleeve (321). The adjusting ring (323) is threaded to the side of the rod (322).
7. A verticality testing device for prefabricated building construction acceptance according to claim 6, characterized in that: One end of the sleeve rod (322) is fixed with a connecting button one (324), and one end of the support rod (31) is rotatably connected to a connecting button two (311). Both the connecting button one (324) and the connecting button two (311) are provided with mounting buttons (325) on their sides. The retaining member (33) includes a mounting plate (331) rotatably connected to the sides of the connecting button one (324) and the connecting button two (311).
8. A verticality testing device for prefabricated building construction acceptance according to claim 7, characterized in that: The mounting plate (331) has multiple notches (332) at equal intervals at both ends; The retaining member (33) also includes a spring button (333) that is movably sleeved on the side of the connecting button one (324) and the connecting button two (311). The side of the spring button (333) is provided with a protrusion (334), which is movably connected in the recess (332).