Tension limiting strength testing device for herringbone ladder

Abstract

The utility model discloses a herringbone ladder tension limiting strength testing device which comprises a base frame, a vertically arranged climbing rod is arranged on the base frame, a climbing assembly and a driving assembly for driving the climbing assembly to move are arranged on the climbing rod, a detachable stretching assembly is installed on the climbing assembly, the stretching assembly is horizontally arranged, and the driving assembly drives the climbing assembly to move. The stretching assembly is provided with two sets of stretching arms which are connected in a sliding mode, the stretching assembly is provided with a second motor which drives the two stretching arms to move in the opposite directions, each stretching arm is provided with a hook and a tension sensor, one end of each tension sensor is connected with the corresponding hook, and the other end of each tension sensor is connected with the corresponding stretching arm; the display screen, the second motor and the tension sensor are all electrically connected with the central control unit, the second motor is used for continuously enabling the two stretching arms to move outwards, transverse tension is applied to the pedal through the tension sensor and the hook, and then the tension limiting strength of the herringbone ladder is tested.

Description

Technical Field

[0001] The utility model relates to the technical field of strength testing of a stepladder, in particular to a device for testing the tension limit strength of a stepladder. Background Art

[0002] A stepladder is a type of climbing tool used to carry out work such as decoration in the space above a flat surface.

[0003] There are two types of herringbone ladders: fixed herringbone ladders and movable herringbone ladders. Early herringbone ladders were generally made of wood. With the development of the metal industry, they are mostly made of aluminum alloy materials.

[0004] Before a herringbone ladder leaves the factory, its performance needs to be tested. Under normal circumstances, a vertical downward tension test needs to be conducted on the ladder treads to test whether the longitudinal load-bearing capacity meets the industry standard. The limit load that the ladder can withstand is also marked in the product manual to remind users to avoid overloading. With the further improvement of industry standards, it is required to test the transverse tension strength of the ladder treads and ensure that the limit strength of the ladder reaches the specified standard. The equipment that originally tested the longitudinal load of the ladder treads cannot be used to test the transverse tension strength of the ladder.

[0005] Therefore, how to design a test device for testing the transverse tension strength of a stepladder has become a technical problem that needs to be solved urgently by people in this field. Utility Model Content

[0006] In order to solve at least one of the technical problems mentioned in the background technology, the purpose of the utility model is to provide a device for testing the tensile strength of a herringbone ladder, so as to solve the problem that traditional testing devices cannot test the lateral tensile strength of a herringbone ladder.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] A device for testing the tensile strength of a stepladder comprises a base frame, a vertically arranged climbing rod is provided on the base frame, a climbing assembly and a driving assembly for driving the climbing assembly to move is provided on the climbing rod, a detachable stretching assembly is installed on the climbing assembly, the stretching assembly is horizontally arranged, two sets of slidably connected stretching arms are provided on the stretching assembly, a second motor for driving the two stretching arms to move in opposite directions is provided on the stretching assembly, a hook and a tension sensor are provided on the stretching arm, one end of the tension sensor is connected to the hook, and the other end is connected to the stretching arm, a central control unit and a display screen are also included, and the display screen, the second motor and the tension sensor are all electrically connected to the central control unit.

[0009] Furthermore, it also includes a connecting piece, one end of which is rotatably connected to the tension sensor, and the other end of the connecting piece is rotatably connected to the hook.

[0010] Furthermore, the connecting member includes two oppositely arranged side panels, each of which is provided with a first plug hole and a second plug hole, in which a third pin shaft and a first pin shaft are rotatably installed respectively, a rotating block is rotatably connected to the first pin shaft, a mounting hole is provided on the rotating block, a second pin shaft connected to the tension sensor is provided in the mounting hole, a ball head is installed on the hook, and the ball head is rotatably connected to the third pin shaft.

[0011] Furthermore, a slide groove is provided on the stretching arm, and also includes a positioning block installed in the slide groove, and the positioning block is fixedly connected to the tension sensor through a positioning bolt.

[0012] Furthermore, the stretching assembly includes a frame, a double-headed screw and two groups of sliders, wherein the second motor is fixedly mounted on the frame, the output shaft of the second motor is fixedly connected to the double-headed screw, the two groups of sliders are respectively threadedly connected to two sections of threads with opposite rotation directions on the double-headed screw, and the sliders are fixedly connected to the stretching arm.

[0013] Furthermore, the inner wall of the frame is also provided with a guide rail arranged along the length direction of the frame, and the sliding block is slidably connected to the guide rail.

[0014] Furthermore, it also includes a transfer assembly, which includes a positioning frame and a connecting frame. The positioning frame is fixedly installed on one of the climbing assembly and the frame, and the connecting frame is fixedly installed on the other one. The connecting frame and the positioning frame are detachably connected.

[0015] Furthermore, the positioning frame is fixedly installed on the climbing assembly, the connecting frame is fixedly installed on the frame, the side wall of the positioning frame is provided with a horizontal positioning cross bar, the connecting frame is provided with a buckle and a buckle groove on the positioning cross bar, the bottom of the positioning frame is provided with a locking hole, and the connecting frame is provided with a stop pin. When the buckle groove is buckled on the positioning cross bar, the stop pin is inserted into the locking hole.

[0016] Furthermore, the climbing assembly includes a rack, a climbing box, a gear and a transmission rod, wherein the rack is fixedly mounted on the climbing rod and vertically arranged, the climbing box is sleeved on the outside of the climbing rod, the transmission rod is rotatably connected to the climbing box, the gear is fixedly mounted on the transmission rod, the gear and the rack are meshed with each other, and the output end of the drive assembly is fixedly connected to the transmission rod.

[0017] Furthermore, the driving assembly includes a first motor and a worm gear reducer, the output shaft of the first motor is connected to the input end of the worm gear reducer, and the output end of the worm gear reducer is fixedly connected to the transmission rod.

[0018] Compared with the prior art, the utility model has the following beneficial effects: the utility model uses the driving assembly and the climbing assembly to raise the stretching assembly to a specified height, and then uses the second motor to adjust the positions of the two stretching arms so that the hook can be hooked on the pedal of the stepladder, and then uses the second motor to continue to move the two stretching arms outward, and applies a lateral tension to the pedal through the tension sensor and the hook, thereby testing the limit tension strength of the stepladder, and the tension sensor transmits the tension signal to the central control unit, and the central control unit is used to control the operation of the second motor, thereby being able to control the tension value of the tension sensor, thereby meeting the load holding test requirements of the limit tension strength test of the stepladder;

[0019] Among them, the stretching component can be removed from the climbing component to avoid the stretching component affecting the vertical tensile test of the ladder. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the front view of the strength test of the stepladder;

[0021] Figure 2 This is a schematic diagram of the structure of the ladder before testing;

[0022] Figure 3 It is a structural schematic diagram of the climbing component;

[0023] Figure 4 It is a schematic diagram of the structure of the stretching component;

[0024] Figure 5 is a schematic diagram of the structure of the adapter component;

[0025] Figure 6 It is a schematic diagram of the local structure of the stretching component;

[0026] Figure 7 is a cross-sectional view of the stretched component;

[0027] Figure 8 The figure is a schematic diagram of the installation of the hook assembly;

[0028] Figure 9 is an expanded schematic diagram of the hook assembly;

[0029] Figure 10 A schematic diagram of the structure of the connector.

[0030] In the figure: 1. Base frame; 11. Climbing rod; 2. Climbing assembly; 21. Rack; 22. Climbing box; 23. Gear; 24. Guide wheel; 25. Transmission rod; 3. Driving assembly; 31. First motor; 32. Worm and worm gear reducer; 4. Adapter assembly; 41. Positioning frame; 411. Positioning cross bar; 412. Locking hole; 42. Connecting frame; 421. Snap groove; 422. Stop pin; 5. Tensile assembly; 51. Frame; 52. Guide slide rail; 53. Slide block; 54. Double-headed lead screw; 55. Second motor; 56. Light-shielding sheet; 57. Position sensor; 6. Tensile arm; 61. Chute; 7. Hooking assembly; 71. Positioning block; 72. Tension sensor; 73. Connector; 731. Side plate; 732. First insertion hole; 733. Second insertion hole; 734. First pin shaft; 735. Rotating block; 7351. Mounting hole; 74. Hook; 75. Ball head; 76. Second pin shaft; 77. Third pin shaft; 78. Positioning bolt; 100. Ladder. Detailed implementation mode

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] This embodiment provides a device for testing the lateral tension limit strength of a ladder, which is mainly used for testing the lateral tension limit strength of a ladder.

[0033] As Figure 1 and Figure 4 shown, in order to be able to test the lateral tension limit strength of the ladder 100, before the test, the ladder 100 is kept in an open state and placed on the front side of the base frame 1. The device includes a tensile assembly 5. Among them, there are two groups of tensile arms 6 arranged oppositely and moving horizontally on the tensile assembly 5. Among them, a hooking assembly 7 for hooking on the pedals of the ladder 100 is provided on the two tensile arms 6. As Figure 8 shown, the hooking assembly 7 includes a hook 74 and a tension sensor 72. Specifically, one end of the tension sensor 72 is connected to the hook 74, and the other end of the tension sensor 72 is connected to the tensile arm 6. It also includes a central control unit and a display screen. Among them, the display screen, the tensile assembly 5 and the tension sensor 72 are all electrically connected to the central control unit.

[0034] In order to realize the movement of the tensile arm 6, in this embodiment, as Figure 4 , Figure 6 and Figure 7As shown, the stretching component 5 includes a frame 51. Among them, a double-headed lead screw 54 is rotatably installed in the frame 51. A second motor 55 is fixedly provided on the frame 51. The output end of the second motor 55 is fixedly connected to the double-headed lead screw 54. A slider 53 is threadedly connected to the double-headed lead screw 54. Among them, the slider 53 is fixedly connected to the stretching arm 6. It is worth noting that the second motor 55 is a stepper motor, and the second motor 55 is electrically connected to the central control unit.

[0035] Here, it is worth noting that the display screen is a touch panel, and the touch panel can apply a standard load and a holding time to the central control unit.

[0036] When the folding ladder 100 is subjected to a lateral tension limiting strength test, the hooks 74 on the two stretching arms 6 are respectively hung on the pedals on both sides of the folding ladder 100. At this time, since the hooks 74 are just hooked on the pedals, the tension sensor 72 does not generate a tension value at this time. The standard load and the holding time are input into the central control unit through the touch panel. At this time, the central control unit controls the second motor 55 to start, thereby driving the double-headed lead screw 54 to rotate, and then driving the stretching arm 6 to move laterally along the length direction of the frame 51 through the slider 53. Here, it is worth noting that the two stretching arms 6 move outward, thereby driving the two hooks 74 to move in the opposite direction, applying a load to the tension sensor 72. When the load of the tension sensor 72 reaches the standard load, the second motor 55 stops working, so that the load of the tension sensor 72 is maintained at the standard load for a period of time. When the holding time is reached, the second motor 55 rotates in the reverse direction, driving the two stretching arms 6 to move towards each other, unloading the lateral tension, and completing the test of the tension limiting strength of the folding ladder 100.

[0037] Here, it is worth noting that the central control unit and the information of inputting the standard load and the holding time to the central control unit by using the touch panel are conventional technical means well-known to those skilled in the art, so no more details will be described in terms of the touch panel and the central control unit.

[0038] In order to improve the stability of the movement of the slider 53, in this embodiment, as Figure 6 and Figure 7 shown, a horizontally arranged guiding slide rail 52 is provided on the frame 51. Among them, the slider 53 is slidably connected to the guiding slide rail 52 to improve the stability of the movement process of the slider 53.

[0039] In order to limit the movement range of the slider 53, in this embodiment, as Figure 7As shown, several position sensors 57 are provided at the bottom of the frame 51. Among them, the position sensors 57 are electrically connected to the central control unit. A light-shielding sheet 56 that can slide through the detection slot of the position sensor 57 is fixedly provided on the slider 53. When the slider 53 moves to the position sensor 57, at this time, the light-shielding sheet 56 is inserted into the detection slot of the position sensor 57 to block the light. At this time, the position sensor 57 transmits a signal to the central control unit, and then the second motor 55 can be controlled to act.

[0040] The actions here include stopping the operation of the second motor 55 and controlling the forward or reverse rotation of the second motor 55.

[0041] When the stepladder 100 is subjected to the horizontal tension limiting strength test, the hook 74 needs to be hooked at the middle position of the pedal of the stepladder 100 to avoid the movement of the stepladder 100 during the test due to the deviation of the hooking positions of the two hooks 74, resulting in a safety accident. The widths of different models of stepladders 100 are different. Therefore, the position of the hook 74 needs to be adjusted adaptively.

[0042] As Figure 8 shown, a chute 61 is provided on the stretching arm 6. Among them, a positioning block 71 is slidably connected to the chute 61. Among them, the tension sensor 72 is connected to the stretching arm 6 through the positioning block 71. During the tension limiting strength test of the stepladder 100, the positioning block 71 slides inside the chute 61 to make the positioning block 71 located at the middle position of the pedal of the stepladder 100, and then the positioning block 71 is fixed to the stretching arm 6 by bolts to avoid the movement of the positioning block 71 during the test.

[0043] During the placement of the stepladder 100, there is a deviation in the inclination angle between the pedal and the horizontal plane. In order to enable the hook 74 to be stably hooked on the pedal, in this embodiment, as Figure 8 and Figure 9 shown, it further includes a connecting piece 73. Among them, the connecting piece 73 is installed between the hook 74 and the tension sensor 72. One end of the connecting piece 73 is rotatably connected to the hook 74, and the other end of the connecting piece 73 is rotatably connected to the tension sensor 72.

[0044] In this embodiment, the tension sensor 72 adopts an S-type force sensor.

[0045] In order to realize the installation of the connecting piece 73, in this embodiment, as Figure 10As shown, the connecting member 73 includes two oppositely arranged side plates 731. The two ends of each side plate 731 are respectively provided with a first insertion hole 732 and a second insertion hole 733. Among them, a third pin shaft 77 and a first pin shaft 734 are respectively inserted into the first insertion hole 732 and the second insertion hole 733. The first pin shaft 734 and the third pin shaft 77 can rotate on the side plate 731. A rotating block 735 is rotatably connected to the first pin shaft 734. An installation hole 7351 is provided on the rotating block 735. Here, the installation hole 7351 is a through hole. As Figure 8 and Figure 9 shown, it further includes a second pin shaft 76 passing through the installation hole 7351 and connected to the tension sensor 72. Among them, the connecting member 73 can rotate around the axis of the second pin shaft 76; a ball head 75 that rotates around the axis of the third pin shaft 77 is provided on the third pin shaft 77. The other end of the ball head 75 is connected to the hook 74. At this time, the hook 74 can rotate around the axis of the third pin shaft 77 through the ball head 75.

[0046] As Figure 9 shown, the tension sensor 72 is fixedly installed on the positioning block 71 through a positioning bolt 78.

[0047] It should be noted here that during the limit tension strength test of the folding ladder 100, the stretching assembly 5 is in a horizontal state.

[0048] In order to be able to measure the limit tension strength of folding ladders 100 of different heights, it is necessary to adjust the height of the stretching assembly 5. Therefore, in this embodiment, as Figure 1 and Figure 2 shown, it further includes a base frame 1. Among them, a climbing rod 11 extending vertically upward is fixedly provided on the base frame 1. A climbing assembly 2 and a driving assembly 3 for driving the climbing assembly 2 to climb are provided on the climbing rod 11. The stretching assembly 5 is installed on the climbing assembly 2.

[0049] In order to ensure the stability of the stretching assembly 5, in this embodiment, two sets of climbing assemblies 2 are provided and are located on the same horizontal plane. At this time, the stretching assembly 5 is connected to the two sets of climbing assemblies 2 at the same time.

[0050] As Figure 3 shown, the climbing assembly 2 includes a rack 21, a climbing box body 22, a transmission rod 25 and a gear 23. Among them, the rack 21 is fixedly installed on the climbing rod 11. The rack 21 is vertically arranged. The climbing box body 22 is sleeved outside the climbing rod 11. The transmission rod 25 is rotatably connected to the climbing box body 22. The gear 23 is fixedly installed on the transmission rod 25 and meshes with the rack 21. The output shaft of the driving assembly 3 is fixedly connected to the transmission rod 25.

[0051] Through the above arrangement, the driving component 3 is utilized to drive the transmission rod 25 to rotate, which in turn can drive the gear 23 to rotate. Since the gear 23 and the rack 21 are meshed with each other, the climbing box 22 can be raised or lowered along the length direction of the rack 21, thereby changing the height of the climbing box 22. Since the stretching component 5 is installed on the climbing component 2, the lifting and lowering of the stretching component 5 can be completed, and the height of the hook component 7 can be changed, so as to facilitate the testing of different types of herringbone ladders 100.

[0052] In order to improve the climbing stability of the climbing assembly 2, in this embodiment, as shown in FIG. Figure 3 As shown, the climbing box 22 is provided with a plurality of guide wheels 24, wherein the peripheral wall of the guide wheel 24 is rollingly connected with the climbing rod 11, and the relative rolling of the guide wheel 24 and the climbing rod 11 can ensure the stable lifting and lowering of the climbing assembly 2.

[0053] When the climbing assembly 2 is lifted to a certain height, in order to prevent the climbing box 22 and the gear 23 from falling downward under the action of gravity, in this embodiment, Figure 3 As shown, the driving assembly 3 includes a first motor 31 and a worm gear reducer 32 , wherein the output shaft of the first motor 31 is connected to the input end of the worm gear reducer 32 , and the output end of the worm gear reducer 32 is connected to the transmission rod 25 .

[0054] Through the above arrangement, the worm gear reduction box 32 is used to transmit the power of the first motor 31 to the transmission rod 25, which can reduce the rotation speed of the first motor 31 and enhance the torque of the transmission rod 25. By utilizing the self-locking principle of the worm gear in the worm gear reduction box 32, when the first motor 31 stops operating, the climbing component 2 can be maintained at a fixed height to prevent the climbing box 22 from falling.

[0055] Since the test device is improved on the basis of the vertical tensile test of the stepladder 100, in order to avoid the installation of the stretching assembly 5 affecting the vertical tensile test experiment, in this embodiment, Figure 2 and Figure 4 As shown, the climbing component 2 is connected to the stretching component 5 via the adapter component 4, and the stretching component 5 and the climbing component 2 can be disassembled by using the adapter component 4.

[0056] Specifically, in this embodiment, if Figure 5As shown in the figure, the adapter assembly 4 includes a positioning frame 41 and a connecting frame 42. Among them, the positioning frame 41 is fixedly installed on the climbing box body 22 by bolts, the connecting frame 42 is fixedly installed on the frame 51, a horizontally arranged positioning cross bar 411 is provided on the side wall of the positioning frame 41, and a buckle groove 421 for hanging on the positioning cross bar 411 is provided on the connecting frame 42. When the stretching assembly 5 is installed on the climbing assembly 2, the buckle groove 421 on the connecting frame 42 can be buckled on the positioning cross bar 411. At this time, the stretching assembly 5 can be hung on the climbing box body 22 under the action of its own gravity, realizing the quick disassembly and assembly of the stretching assembly 5.

[0057] It is worth noting here that positioning frames 41 are provided on the climbing box bodies 22 on both sides of the two climbing rods 11, and the two positioning frames 41 are on the same horizontal plane, which can ensure that the stretching assembly 5 is in a horizontal state after being placed.

[0058] In order to further improve the installation stability of the stretching assembly 5, in this embodiment, as Figure 5 shown, a locking hole 412 is provided at the bottom of the positioning frame 41, and a retaining pin 422 that can be inserted into the locking hole 412 is provided on the connecting frame 42.

[0059] Through the above settings, the installation of the connecting frame 42 and the positioning frame 41 will be introduced here. Lower the climbing assembly 2 to a suitable position, use the hoisting mechanism to lift the stretching assembly 5 to the same horizontal plane as the climbing assembly 2 and tilt the stretching assembly 5 at an angle, then buckle the buckle groove 421 on the connecting frame 42 on the positioning cross bar 411, pull out the retaining pin 422 outward. At this time, gradually relax the hoisting of the stretching assembly 5. After the retaining pin 422 is directly below the locking hole 412, lift the restriction on the retaining pin 422 at this time, so that the retaining pin 422 is inserted into the locking hole 412, thereby realizing the locking of the positioning frame 41 and the connecting frame 42, and further improving the installation stability of the stretching assembly 5.

[0060] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. A device for testing the tensile strength of a ladder, comprising a base frame (1), on which a vertically arranged climbing rod (11) is provided, characterized in that: The climbing rod (11) is provided with a climbing component (2) and a driving component (3) for driving the climbing component (2) to move; the climbing component (2) is installed with a detachable stretching component (5); the stretching component (5) is arranged horizontally; the stretching component (5) is provided with two sets of slidably connected stretching arms (6); the stretching component (5) is provided with a second motor (55) for driving the two stretching arms (6) to move in opposite directions; the stretching arm (6) is provided with a hook (74) and a tension sensor (72); one end of the tension sensor (72) is connected to the hook (74) and the other end is connected to the stretching arm (6); the central control unit and a display screen are also included; the display screen, the second motor (55) and the tension sensor (72) are all electrically connected to the central control unit.

2. A stepladder tension strength testing device according to claim 1, characterized in that: It also includes a connecting member (73), one end of which is rotatably connected to the tension sensor (72), and the other end of which is rotatably connected to the hook (74).

3. A stepladder tension strength testing device according to claim 2, characterized in that: The connecting member (73) comprises two side plates (731) arranged opposite to each other, wherein a first plug hole (732) and a second plug hole (733) are provided on the side plates (731), wherein a third pin shaft (77) and a first pin shaft (734) are rotatably mounted in the first plug hole (732) and the second plug hole (733), respectively, wherein a rotating block (735) is rotatably connected to the first pin shaft (734), wherein a mounting hole (7351) is provided on the rotating block (735), wherein a second pin shaft (76) connected to the tension sensor (72) is provided in the mounting hole (7351), and a ball head (75) is installed on the hook (74), wherein the ball head (75) is rotatably connected to the third pin shaft (77).

4. A stepladder tension strength testing device according to claim 1 or 3, characterized in that: The stretching arm (6) is provided with a slide groove (61) and also includes a positioning block (71) installed in the slide groove (61). The positioning block (71) is fixedly connected to the tension sensor (72) via a positioning bolt (78).

5. The device for testing the tensile strength of a stepladder according to claim 1, characterized in that: The stretching assembly (5) comprises a frame (51), a double-headed screw (54) and two groups of sliders (53), wherein a second motor (55) is fixedly mounted on the frame (51), an output shaft of the second motor (55) is fixedly connected to the double-headed screw (54), the two groups of sliders (53) are respectively threadedly connected to two sections of threads on the double-headed screw (54) with opposite rotation directions, and the sliders (53) are fixedly connected to the stretching arm (6).

6. A stepladder tension strength testing device according to claim 5, characterized in that: The inner wall of the frame (51) is also provided with a guide rail (52) arranged along the length direction of the frame (51), and the sliding block (53) is slidably connected to the guide rail (52).

7. The device for testing the tensile strength of a stepladder according to claim 5, characterized in that: The adapter assembly (4) further comprises a positioning frame (41) and a connecting frame (42), wherein the positioning frame (41) is fixedly mounted on one of the climbing assembly (2) and the frame (51), and the connecting frame (42) is fixedly mounted on the other, and the connecting frame (42) and the positioning frame (41) are detachably connected.

8. The device for testing the tensile strength of a stepladder according to claim 7, characterized in that: The positioning frame (41) is fixedly mounted on the climbing assembly (2), the connecting frame (42) is fixedly mounted on the frame (51), a side wall of the positioning frame (41) is provided with a horizontal positioning cross bar (411), the connecting frame (42) is provided with a buckle and a buckle groove (421) on the positioning cross bar (411), a locking hole (412) is provided at the bottom of the positioning frame (41), and a stop pin (422) is provided on the connecting frame (42), and when the buckle groove (421) is buckled on the positioning cross bar (411), the stop pin (422) is inserted into the locking hole (412).

9. The device for testing the tensile strength of a stepladder according to claim 1, characterized in that: The climbing assembly (2) comprises a rack (21), a climbing box (22), a gear (23) and a transmission rod (25); the rack (21) is fixedly mounted on the climbing rod (11) and is vertically arranged; the climbing box (22) is sleeved on the outer side of the climbing rod (11); the transmission rod (25) is rotatably connected to the climbing box (22); the gear (23) is fixedly mounted on the transmission rod (25); the gear (23) and the rack (21) are meshed with each other; and the output end of the driving assembly (3) is fixedly connected to the transmission rod (25).

10. A stepladder tension strength testing device according to claim 9, characterized in that: The drive assembly (3) comprises a first motor (31) and a worm gear reduction box (32), wherein the output shaft of the first motor (31) is connected to the input end of the worm gear reduction box (32), and the output end of the worm gear reduction box (32) is fixedly connected to the transmission rod (25).

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