Thread inspection device for a trailer hitch

Abstract

The application provides a threaded detection device of a trailer hook, and belongs to the technical field of threaded detection. The threaded detection device of the trailer hook comprises a workbench, a feeding seat, a defective product placing seat, a qualified product placing seat, a positioning mechanism and a threaded detection unit capable of detecting the threads of the trailer hook, which are arranged on the workbench. The workbench is further provided with a transfer mechanism for transferring the trailer hook on the feeding seat to the positioning mechanism. The transfer mechanism can also transfer the trailer hook on the positioning mechanism to the defective product placing seat or the qualified product placing seat. The threaded detection device has high automation. The threaded detection unit is provided with a spring. When the threaded detection unit is pressed, the spring can be retracted, the fixed rotating shaft can be inserted into the movable sleeve more deeply, the impact force of the detection nut on the trailer hook is avoided, and the detection nut and the trailer hook are not easy to be damaged during tapping.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of thread detection, and relates to a thread detection device of a trailer hook. BACKGROUND

[0002] When a vehicle breaks down, the trailer hook needs to be used to tow the vehicle. Currently, there are mainly two kinds of trailer hooks applied to vehicles: one is a welded trailer hook, which is directly welded to the front lower part and rear lower part of the vehicle. Since the welding position of this trailer hook is relatively low, the passability of the vehicle is poor, and it has been less used. The other is a detachable trailer hook, which is mainly connected in a threaded manner. The threaded end of the trailer hook is aligned with the reserved hole on the inner side of the bumper, and the threaded end is tightened to realize the fastening of the trailer hook. In order to prevent safety hazards caused by the phenomenon that the trailer hook thread cannot be screwed in place and the thread is damaged, the thread of the produced trailer hook needs to be detected.

[0003] As disclosed in Chinese patent application No.

CN201910089205.4

[0004] The purpose of the present application is to solve the above-mentioned problems existing in the prior art, and to provide a thread detection device of a trailer hook, which has high automation. The telescopic thread detection unit can automatically detect the external thread on the trailer hook, avoid the impact force of the detection nut on the trailer hook, and prevent the detection nut and the trailer hook from being damaged during tapping.

[0005] The purpose of the present application can be realized by the following technical solutions: a thread detection device of a trailer hook, comprising a workbench, a feeding seat, a defective product placing seat, a qualified product placing seat, a positioning mechanism and a thread detection unit capable of detecting the thread of the trailer hook, which are arranged on the workbench, and a transfer mechanism for transferring the trailer hook on the feeding seat to the positioning mechanism, the transfer mechanism can also transfer the trailer hook on the positioning mechanism to the defective product placing seat or the qualified product placing seat, the positioning mechanism comprises a detection frame in the shape of a square box, a transposition cylinder, a transposition track, a translation clamping seat and a clamping assembly capable of clamping the trailer hook, the transposition cylinder and the detection frame are fixed on the workbench, the transposition track is fixed in the detection frame, the translation clamping seat is embedded on the transposition track and is pushed by the transposition cylinder to translate along the transposition track, the clamping assembly comprises a clamping cylinder and a clamping head fixed on the translation clamping seat, the clamping head is arranged on the execution end of the clamping cylinder and can clamp the trailer hook under the drive of the clamping cylinder; the upper end surface of the detection frame is fixed with a detection stand, and the thread detection unit has two and is arranged side by side on the detection stand.

[0006] The worker puts the trailer hook to be detected on the feeding seat, the transfer mechanism clamps and transfers the trailer hook on the feeding seat to the clamping assembly of the positioning mechanism, and the trailer hook is clamped and positioned by the clamping assembly. The transposition cylinder pushes the translation clamping seat to switch the detection station under the two thread detection units, the two thread detection units detect the trailer hook in turn by passing the gauge and stopping the gauge, and after the detection is completed, the trailer hook is put into the defective product placing seat or the qualified product placing seat through the transfer mechanism according to the result, so that the worker can take away the trailer hook.

[0007] Further, the thread detection unit comprises a detection motor fixed on the detection stand, a torque sensor, a single-chip microcomputer, a fixed rotating shaft, a movable sleeve, a mounting shaft and a lifting cylinder, the detection motor is fixed on the detection stand, the detection motor is connected with the upper end of the torque sensor in power through a shaft coupling, the lower end of the torque sensor is connected with the upper end of the fixed rotating shaft in power through a shaft coupling, the torque sensor is connected with the single-chip microcomputer through a signal line, the single-chip microcomputer controls the start and stop of the detection motor, the fixed rotating shaft is inserted into the movable sleeve and axially slides with the movable sleeve, a strip-shaped sliding groove is formed in the peripheral wall of the movable sleeve, a pin shaft is fixed on the fixed rotating shaft and slides along the length direction of the strip-shaped sliding groove, an intermediate sleeve is fixedly connected to the lower end of the mounting shaft, a vertical sliding rail is also fixed on the detection stand, a lifting block is slidably arranged on the vertical sliding rail, the lifting cylinder is fixed on the detection stand and located above the vertical sliding rail, the lifting block is connected with the lifting cylinder, the outer end of the lifting block is sleeved with the mounting shaft and slides with the mounting shaft, upper and lower limit blocks are respectively fixed on the upper and lower ends of the mounting shaft, a spring is sleeved on the mounting shaft, the upper end of the spring abuts against the lifting block, the lower end of the spring abuts against the upper surface of the lower limit block, and the upper end surface of the lifting block abuts against the lower surface of the upper limit block.

[0008] The detection motor drives the torque sensor linkage, the torque sensor drives the fixed rotating shaft through the shaft coupling, the fixed rotating shaft drives the movable sleeve, the movable sleeve drives the intermediate sleeve, the intermediate sleeve drives the mounting shaft, and finally the mounting shaft drives the detection nut at the lower end of the mounting shaft to rotate. The lifting cylinder is started, and the lifting block is pushed to slide up and down along the vertical slide rail. When the lifting block slides downward, the lifting block extrudes the spring, the spring extrudes the lower end of the mounting shaft, the movable sleeve slides downward relative to the fixed rotating shaft, and the detection nut detects the external thread on the trailer hook during the descending process. The single-chip microcomputer can receive the data sent by the torque sensor. The torque of the through nut shall not exceed the preset value, otherwise it is judged as a defective product. After the detection is completed, the detection motor is controlled to stop and rotate in the reverse direction, and the lifting cylinder drives the lifting block to move upward to reset, so that the detection nut is separated from the trailer hook.

[0009] Further, a hexagonal slot is formed on the lower limit block of the mounting shaft, and a detection nut is embedded in the hexagonal slot. A locking hole is formed on the side surface of the lower limit block, and a locking bolt is threadedly connected in the locking hole.

[0010] Further, the detection nut is divided into a through nut and a stop nut, one of the thread detection units is provided with the through nut, and the other thread detection unit is provided with the stop nut.

[0011] If the through nut can be screwed into the external thread at the upper end of the trailer hook, and the torque does not exceed the preset value, and the stop nut cannot be screwed in, the trailer hook is a qualified product. If the through nut cannot be screwed into the external thread at the upper end of the trailer hook or the stop nut can be screwed in, the trailer hook is a defective product.

[0012] Further, the transfer mechanism comprises a track frame, a transfer motor, a sliding plate, an adjusting motor and a transfer cylinder. The track frame is fixed on the workbench, the transfer motor is fixed on one end of the track frame, a screw rod is rotatably connected in the track frame, the inner side of the sliding plate can translate along the track frame and is threadedly connected with the screw rod, the screw rod is power-connected with the transfer motor, the adjusting motor is fixed on the outer side of the sliding plate, a guide column is fixed on the sliding plate, a double-track cylinder capable of driving itself to ascend and descend along the guide column is slidably arranged on the guide column, the adjusting motor is fixed on the double-track cylinder, a rotating disc synchronously rotating with the output shaft of the adjusting motor is fixed on the output shaft, the transfer cylinder is fixed on the rotating disc, and a material taking clamp is mounted on the execution end of the transfer cylinder.

[0013] The transfer motor drives the screw to rotate, drives the sliding plate to move horizontally along the horizontal direction, adjusts the motor to drive the rotating disc to rotate, and makes the head of the transfer cylinder downward, and the double-track cylinder drives itself to descend along the guide slide column, so that the material taking clamp head clamps the trailer hook. The double-track cylinder is lifted, the rotating disc rotates the transfer cylinder to the horizontal position, the transfer motor drives the sliding plate to move to the positioning mechanism, and when it moves to the predetermined position, the driving clamping head of the clamping cylinder clamps the trailer hook, and the material taking clamp head releases the trailer hook. After the whole detection is completed, the material taking clamp head clamps the trailer hook again, and the clamping head releases the trailer hook. The sliding plate moves backward, the material taking clamp head is driven by the rotating disc to turn to the downward direction, and the double-track cylinder moves downward to put the detected trailer hook into the defective product placing seat or the qualified product placing seat.

[0014] Further, the defective product placing seat, the qualified product placing seat and the feeding seat are arranged side by side, the feeding seat comprises a positioning block for transversely embedding the trailer hook, a translation guide rail fixed on the workbench and a flat push cylinder for sliding the positioning block along the translation guide rail, and the defective product placing seat, the qualified product placing seat and the feeding seat have the same structure.

[0015] Further, the detection frame is fixed with limiting rods on both sides which can abut against the translation clamping seat. The translation clamping seat is accurately positioned by the limiting rods when the displacement cylinder drives the translation clamping seat to move along the displacement track, so that the translation clamping seat stays at the detection station.

[0016] Further, the translation clamping seat is fixed with a material blocking block which has a supporting step below the clamping head. The material blocking block can prevent the trailer hook from falling downward and also prevent the trailer hook from being rotated by the detected nut.

[0017] Compared with the prior art, the thread detection device of the trailer hook has the following advantages:

[0018] 1. High degree of automation, the thread detection unit can automatically detect the external thread on the trailer hook, the clamping head can firmly clamp the trailer hook, and the material blocking block can also cooperate with the clamping head to block the downward movement and rotation of the trailer hook.

[0019] 2. Workers do not need to transfer the trailer hook during detection, so that the workers can be away from the positioning mechanism and the thread detection unit, avoiding accidental touch, affecting the detection result and even causing personal injury.

[0020] 3. The thread detection unit has a spring which can contract when pressed, making the fixed rotating shaft more deeply inserted into the movable sleeve, avoiding the impact force of the detection nut on the trailer hook, so that the detection nut and the trailer hook are not easily damaged during tapping. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic view of the thread detection device of the trailer hook.

[0022] Figure 2 This is a distribution diagram of the defective product placement seat, the qualified product placement seat, and the loading seat.

[0023] Figure 3 This is a schematic diagram of the transfer mechanism.

[0024] Figure 4 This is a schematic diagram of the positioning mechanism.

[0025] Figure 5 This is a schematic diagram of the thread detection unit.

[0026] Figure 6 This is a cross-sectional view of the thread detection unit.

[0027] In the diagram: 1. Workbench; 2. Loading seat; 21. Positioning block; 22. Translation guide rail; 23. Push cylinder; 3. Defective product placement seat; 4. Qualified product placement seat; 5. Positioning mechanism; 51. Detection frame; 52. Shifting cylinder; 53. Shifting rail; 54. Translation bracket; 55. Clamping cylinder; 56. Clamping head; 57. Detection stand; 58. Limit rod; 59. Stop block; 510. Support step; 6. Thread detection unit; 61. Detection motor; 62. Torque sensor; 63. Fixed shaft; 64. Movable sleeve; 65. Installation. 66. Shaft; 67. Lifting cylinder; 68. Coupling; 69. Strip groove; 610. Pin; 611. Intermediate sleeve; 612. Vertical slide rail; 613. Lifting block; 614. Upper limit block; 615. Lower limit block; 616. Spring; 617. Detection nut; 618. Locking hole; 719. Locking bolt; 70. Transfer mechanism; 71. Track frame; 72. Transfer motor; 73. Sliding plate; 74. Adjusting motor; 75. Transfer cylinder; 76. Guide column; 77. Double-rail cylinder; 78. Turntable; 79. Material chuck; 8. Trailer hook. Detailed Implementation

[0028] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0029] like Figure 1 As shown, the thread inspection device for this trailer hook includes a workbench 1 and a loading seat 2, a defective product placement seat 3, a qualified product placement seat 4, a positioning mechanism 5, and a thread inspection unit 6 for inspecting the threads of the trailer hook 8, all mounted on the workbench 1. The workbench 1 is also equipped with a transfer mechanism 7 that transfers the trailer hook 8 from the loading seat 2 to the positioning mechanism 5. The transfer mechanism 7 can also transfer the trailer hook 8 from the positioning mechanism 5 to the defective product placement seat 3 or the qualified product placement seat 4.

[0030] The positioning mechanism 5 comprises a detection frame 51 in the shape of a square box, a transposition cylinder 52, a transposition track 53, a translation holder 54 and a clamping assembly capable of clamping the trailer hook 8. The transposition cylinder 52 and the detection frame 51 are fixed on the workbench 1, the transposition track 53 is fixed in the detection frame 51, the translation holder 54 is embedded on the transposition track 53 and is pushed by the transposition cylinder 52 to translate along the transposition track 53, and the clamping assembly comprises a clamping cylinder 55 and a clamping head 56 fixed on the translation holder 54. The clamping head 56 is arranged on the execution end of the clamping cylinder 55 and can clamp the trailer hook 8 under the drive of the clamping cylinder 55. The detection frame 51 is fixed with limiting rods 58 capable of abutting against the translation holder 54 on both sides respectively. The transposition cylinder 52 pushes the translation holder 54 to move along the transposition track 53, and the limiting rods 58 can accurately position the position of the translation holder 54 so that the translation holder 54 stays on the detection station. The translation holder 54 is fixed with a material blocking block 59, and the material blocking block 59 has a support step 510 located below the clamping head 56. The material blocking block 59 can avoid the trailer hook 8 from falling down and also avoid the trailer hook 8 from being rotated with the detection nut 616.

[0031] As Figure 4 , Figure 5 , Figure 6As shown, the upper end surface of the detection frame 51 is fixed with a detection stand 57, and the threaded detection unit 6 has two and is arranged side by side on the detection stand 57. The threaded detection unit 6 includes a detection motor 61 fixed on the detection stand 57, a torque sensor 62, a single-chip microcomputer, a fixed rotating shaft 63, a movable sleeve 64, a mounting shaft 65 and a lifting cylinder 66, the detection motor 61 is fixed on the detection stand 57, the detection motor 61 is power-connected with the upper end of the torque sensor 62 through a shaft coupling 67, the lower end of the torque sensor 62 is power-connected with the upper end of the fixed rotating shaft 63 through the shaft coupling 67, the torque sensor 62 is connected with the single-chip microcomputer through a signal line, the single-chip microcomputer controls the start and stop of the detection motor 61, the fixed rotating shaft 63 is inserted into the movable sleeve 64 and axially slidably fitted with the movable sleeve 64, a strip-shaped sliding groove 68 is formed in the peripheral wall of the movable sleeve 64, a pin shaft 69 is fixed on the fixed rotating shaft 63 and inserted into the strip-shaped sliding groove 68 and slides along the length direction of the strip-shaped sliding groove 68, an intermediate sleeve 610 is fixedly connected with the lower end of the movable sleeve 64, the mounting shaft 65 is fixedly connected at the lower end of the intermediate sleeve 610, a vertical sliding rail 611 is also fixed on the detection stand 57, a lifting block 612 is slidably arranged on the vertical sliding rail 611, the lifting cylinder 66 is fixed on the detection stand 57 and located above the vertical sliding rail 611, the lifting block 612 is connected with the lifting cylinder 66, the lifting block 612 is slidably fitted with the mounting shaft 65 by being sleeved on the outer side of the mounting shaft 65, an upper limit block 613 and a lower limit block 614 are respectively fixed on the upper end and the lower end of the mounting shaft 65, a spring 615 is sleeved on the mounting shaft 65, the upper end of the spring 615 abuts against the lifting block 612, the lower end of the spring 615 abuts against the upper surface of the lower limit block 614, and the upper end surface of the lifting block 612 abuts against the lower surface of the upper limit block 613.

[0032] The detection motor 61 drives the torque sensor 62 to rotate, the torque sensor 62 drives the fixed rotating shaft 63 to rotate through the shaft coupling 67, the fixed rotating shaft 63 drives the movable sleeve 64 to rotate, the movable sleeve 64 drives the intermediate sleeve 610 to rotate, the intermediate sleeve 610 drives the mounting shaft 65 to rotate, and finally drives the detection nut 616 at the lower end of the mounting shaft 65 to rotate. The lifting cylinder 66 is started to drive the lifting block 612 to slide up and down along the vertical sliding rail 611, when the lifting block 612 slides downward, the lifting block 612 extrudes the spring 615, the spring 615 extrudes the lower end of the mounting shaft 65, the movable sleeve 64 slides downward relative to the fixed rotating shaft 63, and the detection nut 616 detects the external thread on the tow hook 8 in the descending process. The single-chip microcomputer can receive the data sent by the torque sensor 62, the torque of the threaded nut shall not exceed the preset value, otherwise it is judged as a defective product. After the detection is completed, the detection motor 61 is controlled to stop and rotate reversely, at the same time, the lifting cylinder 66 drives the lifting block 612 to move upward to reset, so that the detection nut 616 is separated from the tow hook 8.

[0033] The lower limit block 614 of the mounting shaft 65 is provided with a hexagonal slot, a detection nut 616 is embedded in the hexagonal slot, a locking hole 617 is formed on the side surface of the lower limit block 614, and a locking bolt 618 is threadedly connected in the locking hole 617. The detection nut 616 is divided into a through gauge nut and a stop gauge nut, one of the threaded detection units 6 is provided with the through gauge nut, and the other threaded detection unit 6 is provided with the stop gauge nut.

[0034] If the through gauge nut can be screwed into the external thread at the upper end of the trailer hook 8, and the torque does not exceed the preset value, and the stop gauge nut cannot be screwed in, the trailer hook 8 is a qualified product. If the through gauge nut cannot be screwed into the external thread at the upper end of the trailer hook 8 or the stop gauge nut can be screwed in, the trailer hook 8 is a defective product.

[0035] As shown in Figure 3 The transfer mechanism 7 includes a rail frame 71, a transfer motor 72, a sliding plate 73, an adjusting motor 74, and a transfer cylinder 75. The rail frame 71 is fixed on the workbench 1, the transfer motor 72 is fixed on one end of the rail frame 71, a screw rod is rotatably connected in the rail frame 71, the sliding plate 73 is threadedly connected with the screw rod and can translate along the rail frame 71, the screw rod is power-connected with the transfer motor 72, the adjusting motor 74 is fixed on the outer side of the sliding plate 73, a guide sliding column 76 is fixed on the sliding plate 73, a double-track cylinder 77 capable of driving itself to ascend and descend along the guide sliding column 76 is slidably arranged on the guide sliding column 76, the adjusting motor 74 is fixed on the double-track cylinder 77, a rotating disc 78 synchronously rotating with the output shaft of the adjusting motor 74 is fixed on the output shaft, the transfer cylinder 75 is fixed on the rotating disc 78, and a material taking chuck 79 is mounted on the execution end of the transfer cylinder 75.

[0036] As shown in Figure 2 The defective product placing seat 3, the qualified product placing seat 4, and the feeding seat 2 are arranged side by side in sequence. The feeding seat 2 includes a positioning block 21 for transversely embedding the trailer hook 8, a translation guide rail 22 fixed on the workbench 1, and a flat pushing cylinder 23 for sliding the positioning block 21 along the translation guide rail 22. The defective product placing seat 3 and the qualified product placing seat 4 have the same structure as the feeding seat 2. Workers place the trailer hook 8 on the positioning block 21 of the feeding seat 2, and the flat pushing cylinder 23 pushes the positioning block 21 to the transfer mechanism 7. The flat pushing cylinders 23 of the defective product placing seat 3 and the qualified product placing seat 4 push the positioning block 21 to the workers, which facilitates the workers to take out the trailer hook 8.

[0037] The detection operation process is as follows: the worker puts the trailer hook 8 to be detected on the feeding seat 2, the transfer motor 72 on the transfer mechanism 7 is started and drives the screw to rotate, the screw drives the sliding plate 73 to move horizontally in the horizontal direction, the adjusting motor 74 drives the rotating disc 78 to rotate, the head of the transfer cylinder 75 is downward, at the same time, the double-track cylinder 77 drives itself to descend along the guide slide column 76, and the material taking clamp head 79 clamps the trailer hook 8 horizontally placed on the feeding seat 2. The double-track cylinder 77 is lifted, the rotating disc 78 rotates the transfer cylinder 75 to the horizontal position, the trailer hook 8 is turned to the vertical state, the transfer motor 72 drives the sliding plate 73 to move to the positioning mechanism 5, when moving to the predetermined position, the driving clamping head 56 of the clamping cylinder 55 clamps the trailer hook 8, and the material taking clamp head 79 is loosened and then retreats.

[0038] The transposition cylinder 52 pushes the translation clamp seat 54 to switch the detection station below the two screw detection units 6, the two screw detection units 6 detect the trailer hook 8 in turn, and the detection is completed, the material taking clamp head 79 clamps the trailer hook 8 again, and the clamping head 56 is loosened, the sliding plate 73 moves backward, the material taking clamp head 79 is driven by the rotating disc 78 to turn to the downward direction, the double-track cylinder 77 is lowered, and the detected trailer hook 8 is put into the defective product placing seat 3 or the qualified product placing seat 4, so that the worker can take away the trailer hook 8.

[0039] The specific embodiments described herein are merely illustrative of the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them with similar ways, but will not deviate from the spirit of the present application or exceed the scope defined by the appended claims.

Claims

1. A thread detection device for trailer hooks, comprising a workbench (1) and a feeding seat (2), a defective product placing seat (3), a qualified product placing seat (4), a positioning mechanism (5) and a thread detection unit (6) capable of detecting the thread of a trailer hook (8) arranged on the workbench (1), characterized in that, The workbench (1) is further provided with a transfer mechanism (7) for transferring the trailer hook (8) on the feeding seat (2) to the positioning mechanism (5), and the transfer mechanism (7) can also transfer the trailer hook (8) on the positioning mechanism (5) to the defective product placing seat (3) or the qualified product placing seat (4); the positioning mechanism (5) comprises a detection frame (51) in the shape of a square box, a transposition cylinder (52), a transposition track (53), a translation clamping seat (54) and a clamping assembly capable of clamping the trailer hook (8); the transposition cylinder (52) and the detection frame (51) are fixed on the workbench (1); the transposition track (53) is fixed in the detection frame (51); the translation clamping seat (54) is embedded on the transposition track (53) and is pushed by the transposition cylinder (52) to translate along the transposition track (53); the clamping assembly comprises a clamping cylinder (55) and a clamping head (56) fixed on the translation clamping seat (54); the clamping head (56) is arranged on the execution end of the clamping cylinder (55) and can clamp the trailer hook (8) under the drive of the clamping cylinder (55).The upper end face of the detection frame (51) is fixed with a detection stand (57), two screw detection units (6) are arranged side by side on the detection stand (57), the screw detection unit (6) comprises a detection motor (61) fixed on the detection stand (57), a torque sensor (62), a single-chip microcomputer, a fixed rotating shaft (63), a movable sleeve (64), a mounting shaft (65) and a lifting cylinder (66), the detection motor (61) is fixed on the detection stand (57), the detection motor (61) is power-connected with the upper end of the torque sensor (62) through a shaft coupling (67), the lower end of the torque sensor (62) is power-connected with the upper end of the fixed rotating shaft (63) through a shaft coupling (67), the torque sensor (62) is connected with the single-chip microcomputer through a signal line, the single-chip microcomputer controls the start and stop of the detection motor (61), the fixed rotating shaft (63) is inserted into the movable sleeve (64) and axially slidably connected with the movable sleeve (64), a strip-shaped sliding groove (68) is formed in the peripheral wall of the movable sleeve (64), a pin shaft (69) is fixed on the fixed rotating shaft (63) and slides along the length direction of the strip-shaped sliding groove (68), the lower end of the movable sleeve (64) is fixedly connected with an intermediate sleeve (610), the mounting shaft (65) is fixedly connected to the lower end of the intermediate sleeve (610), the detection stand (57) is further fixed with a vertical sliding rail (611), a lifting block (612) is slidably arranged on the vertical sliding rail (611), the lifting cylinder (66) is fixed on the detection stand (57) and located above the vertical sliding rail (611), the lifting block (612) is connected with the lifting cylinder (66), the outer end of the lifting block (612) is sleeved on the mounting shaft (65) and slidably connected with the mounting shaft (65), the upper and lower ends of the mounting shaft (65) are respectively fixed with an upper limiting block (613) and a lower limiting block (614), a spring (615) is sleeved on the mounting shaft (65), the upper end of the spring (615) abuts against the lifting block (612), the lower end of the spring (615) abuts against the upper surface of the lower limiting block (614), and the upper end surface of the lifting block (612) abuts against the lower surface of the upper limiting block (613).

2. A thread inspection device for a trailer hitch according to claim 1, wherein, The lower limit block (614) of the mounting shaft (65) is provided with a hexagonal slot, a detection nut (616) is embedded in the hexagonal slot, a locking hole (617) is formed in the side surface of the lower limit block (614), and a locking bolt (618) is threadedly connected in the locking hole (617).

3. A thread inspection device for a trailer hitch according to claim 2, wherein, The detection nut (616) is divided into a through gauge nut and a stop gauge nut, one of the threaded detection units (6) is provided with the through gauge nut, and the other threaded detection unit (6) is provided with the stop gauge nut.

4. A thread inspection device for a trailer hitch according to claim 1, wherein, The transfer mechanism (7) comprises a track frame (71), a transfer motor (72), a sliding plate (73), an adjusting motor (74) and a transfer cylinder (75), the track frame (71) is fixed on the workbench (1), the transfer motor (72) is fixed on one end of the track frame (71), a screw rod is rotatably connected in the track frame (71), the sliding plate (73) is threadedly connected with the screw rod and can translate along the track frame (71) on the inner side, the screw rod is connected with the transfer motor (72), the adjusting motor (74) is fixed on the outer side of the sliding plate (73), the sliding plate (73) is fixed with a guide sliding column (76), the guide sliding column (76) is slidably provided with a double-track cylinder (77) capable of driving itself to ascend and descend along the guide sliding column (76), the adjusting motor (74) is fixed on the double-track cylinder (77), a rotating disc (78) is fixed on the output shaft of the adjusting motor (74) and rotates synchronously, the transfer cylinder (75) is fixed on the rotating disc (78), and a material taking chuck (79) is mounted on the execution end of the transfer cylinder (75).

5. A thread inspection device for a trailer hitch according to claim 4, wherein, The defective product placing seat (3), the qualified product placing seat (4) and the feeding seat (2) are sequentially and side by side arranged, the feeding seat (2) comprises a positioning block (21) for transversely embedding a trailer hook (8), a translation guide rail (22) fixed on the workbench (1) and a flat pushing cylinder (23) for sliding the positioning block (21) along the translation guide rail (22), and the defective product placing seat (3) and the qualified product placing seat (4) have the same structure as the feeding seat (2).

6. A thread inspection device for a trailer hitch according to claim 1, wherein, The detection frame (51) is fixed with a limiting rod (58) on each side and can abut against the translation clamping seat (54).

7. A thread inspection device for a trailer hitch according to claim 6, wherein, The translation clamping seat (54) is fixed with a material blocking block (59), and the material blocking block (59) has a supporting step (510) below the clamping head (56).

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