Auxiliary film feeding mechanism of packaging machine

Abstract

The utility model relates to the technical field of packaging machines, in particular to an auxiliary film feeding mechanism of a packaging machine, which adopts a single-motor design, does not need a special tensioning system and a sensor, reduces the failure rate, and reduces the equipment cost and the operation cost. Comprising a rack, a film winding shaft and a film unwinding shaft, the film winding shaft and the film unwinding shaft are rotationally installed on the rack through rotating shafts, the film winding shaft winds a packaging film, and the film unwinding shaft releases the packaging film; the driving motor is installed on the machine frame, an output shaft of the driving motor is in transmission connection with the film collecting shaft, the brake disc is concentrically installed on a rotating shaft of the film releasing shaft, the shaft rod is installed on the machine frame and located below the film releasing shaft, the middle of the connecting rod is rotationally connected with the shaft rod, and the connecting rod is connected with the pressing roller. The pressing roller is rotationally installed at the right end of the connecting rod and located above the packaging film between the film winding shaft and the film unwinding shaft, and the brake assembly is installed at the left end of the connecting rod and matched and aligned with the brake disc.

Description

Technical Field

[0001] The utility model relates to the technical field of packaging machines, in particular to an auxiliary film-feeding mechanism of a packaging machine. Background Art

[0002] The auxiliary film feeding mechanism of the packaging machine is one of the commonly used mechanisms of the packaging equipment, which is used to draw the packaging film from the packaging film reel and convey it backward. Various auxiliary film feeding mechanisms are proposed in the prior art. For example, the film feeding device for the soft-drawing packaging machine proposed in the Chinese utility model patent with the publication number CN216970179U, the film feeding device is provided with a film storage mechanism, so that the packaging film released due to inertia in the film releasing mechanism can be stored, and at the same time, the film releasing mechanism can continuously release the film at a certain speed, uniform or non-uniform, and the excess film is stored by the film storage mechanism. When the film pulling mechanism is intermittent, the film storage mechanism always stores the packaging film released by the film pulling mechanism, and when the film pulling mechanism is in action, the packaging film stored in the film storage mechanism can be pulled out, so that the film releasing mechanism and the film pulling mechanism can operate independently of each other; the film pulling mechanism includes a self-powered front film pulling roller group and a self-powered rear film pulling roller group, and the cutting and tearing mechanism is arranged between the two groups of film pulling roller groups, and the tension of the packaging film between them is adjusted by the two groups of film pulling roller groups.

[0003] The above-mentioned film feeding device adopts the traditional dual-motor film retraction and release to assist the transportation and operation of the packaging film, but the dual motors also require the packaging film tensioning system and the addition of some sensors. The equipment structure is complex and the manufacturing cost is high, which leads to a significant increase in the equipment failure rate and the operating cost will also increase. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides an auxiliary film feeding mechanism for a packaging machine which adopts a single motor design, does not require a special tensioning system and a sensor, reduces the failure rate, and reduces the equipment cost and the operating cost.

[0005] The utility model discloses an auxiliary film feeding mechanism for a packaging machine, comprising a frame, a film collecting shaft and a film unloading shaft, wherein the film collecting shaft and the film unloading shaft are respectively rotatably mounted on the frame through rotating shafts, the film collecting shaft rewinds the packaging film, and the film unloading shaft releases the packaging film; the utility model also comprises a driving motor, a brake disc, an axle rod, a connecting rod, a pressure roller and a brake assembly, wherein the driving motor is mounted on the frame, the output shaft of the driving motor is transmission-connected with the film collecting shaft, the brake disc is concentrically mounted on the rotating shaft of the film unloading shaft, the axle rod is mounted on the frame, and the axle rod is located below the film unloading shaft The middle part of the connecting rod is rotatably connected with the shaft rod, the pressure roller is rotatably installed on the right end of the connecting rod, the pressure roller is located above the packaging film between the film-winding shaft and the film-releasing shaft, the brake assembly is installed on the left end of the connecting rod, and the brake assembly is matched and aligned with the brake disc; when working, the packaging film roll is loaded on the film-releasing shaft, and the packaging film is drawn out from the packaging film roll and rolled up on the film-winding shaft. When the film is moving, the driving motor drives the film-winding shaft to rotate, and the film-winding shaft winds up and tightens the packaging film, so that the packaging film between the film-winding shaft and the film-releasing shaft is stretched and straightened. The packaging film lifts the pressure roller, and the pressure roller drives the right end of the connecting rod to rotate upward around the shaft rod, so that the left end of the connecting rod drives the brake assembly to rotate downward and disengage from the brake disc, so that the film-releasing shaft can rotate freely, thereby making the packaging film smoothly drawn out. At this time, the gravity of the pressure roller acts on the packaging film between the film-collecting shaft and the film-releasing shaft to press the packaging film downward and tighten it. When the driving motor stops, the film-collecting shaft stops rotating, and the gravity of the pressure roller presses the packaging film between the film-collecting shaft and the film-releasing shaft downward for a distance again, so that the pressure roller drives the right end of the connecting rod to rotate downward around the shaft rod, so that the left end of the connecting rod drives the brake assembly to rotate downward and frictionally contact with the brake disc, thereby stopping the film-releasing shaft. The single-motor design reduces the equipment cost, does not require a special packaging film tensioning system and sensor, simplifies the structure, reduces the failure rate, and realizes the smooth operation of the auxiliary film feeding of the packaging film; adopts a fully mechanical mechanism without corresponding components such as a motor cylinder, has reliable operation, improved service life, and reduced operating costs.

[0006] Preferably, the brake assembly includes a mounting pin, a brake pad mounting plate and a brake pad, the mounting pin is mounted on the left end of the connecting rod, the lower end of the brake pad mounting plate is connected to the mounting pin, and the brake pad is installed on the side of the brake pad mounting plate facing the brake disc; after adjusting the angle and distance between the brake pad and the brake disc, the brake pad mounting plate and the mounting pin are locked and fixed, and when the connecting rod rotates around the shaft, the connecting rod drives the brake pad mounting plate and the brake pad to approach or move away from the brake disc through the mounting pin, thereby achieving friction braking and disengagement release of the brake pad on the brake disc, with mature technology and good practicality.

[0007] Preferably, it also includes a long slide groove and a locking nut. The long slide groove is set on the right end of the connecting rod, the central axis of the pressure roller is inserted into the long slide groove, and the locking nut is rotatably screwed on the central axis to lock the pressure roller on the connecting rod; after adjusting the position of the pressure roller along the long slide groove, the locking nut is tightened to lock it, and the distance between the pressure roller and the shaft rod is adjusted, thereby adjusting the length of the force arm, and then adjusting the friction between the brake pad and the brake disc to improve versatility.

[0008] Preferably, it also includes a spring sheet and a latch, the brake pad mounting plate is movably connected to the mounting pin, the upper end of the spring sheet is rotationally connected to the brake pad mounting plate, and the lower end of the spring sheet is connected to the left end of the connecting rod through the latch; when the brake pad is pressed against the brake disc and the pressure roller continues to descend, the left end of the connecting rod compresses the spring sheet upward through the latch, so that the pressure roller can always tension the packaging film downward to prevent the packaging film from loosening.

[0009] Preferably, it also includes an adjustment plate, which is installed at the left end of the connecting rod. The adjustment plate is provided with a plurality of insertion holes for the plug-ins, and the plurality of insertion holes are vertically arranged; the insertion holes of the plug-ins on the adjustment plate are adjusted to adjust the angle between the brake pad mounting plate and the connecting rod, thereby adjusting the friction and clamping force between the brake pad and the brake disc, which has good practicality.

[0010] Preferably, it also includes a shock absorber and a spring, the lower end of the shock absorber is rotatably connected to the frame, the upper end of the shock absorber is connected to the connecting rod, and the shock absorber is mounted with a spring, and the tension of the spring pulls the right end of the connecting rod downward; the shock absorber and the spring pull the right end of the connecting rod and the pressure roller downward, so that the pressure roller presses down the packaging film between the film collecting shaft and the film releasing shaft, and the tensioning force on the packaging film is adjusted by adjusting the elastic force of the spring, and the clamping force between the brake pad and the brake disc can also be adjusted.

[0011] Preferably, it also includes multiple code disk marks, a bracket, a speed meter and a contact switch. Multiple code disk marks are evenly arranged on the circumference of the brake disk. The bracket is installed on the shaft rod, the speed meter is installed on the bracket, the speed meter is aligned with the code disk mark, the contact switch is installed on the bracket, and the contact arm of the contact switch is aligned with the brake pad. When the brake disk rotates, it drives the multiple code disk marks to rotate. The speed meter measures the rotation speed of the brake disk by detecting the time the code disk mark passes. When the brake pad approaches the brake disk, the contact arm of the contact switch is pushed by the brake pad to generate a signal, and the time one when the signal is generated and the time two when the brake disk stops rotating are recorded. The time difference between the time two and the time one is the braking time of the brake pad on the brake disk. When the braking time is too long, the relative distance between the brake pad and the brake disk is adjusted by adjusting the installation position of the pin, so as to detect the film running state and the braking effect of the packaging film and improve practicality.

[0012] Compared with the prior art, the beneficial effects of the utility model are as follows: the single-motor design reduces equipment costs, does not require a special packaging film tensioning system and sensor, simplifies the structure, reduces the failure rate, and realizes smooth auxiliary film feeding of the packaging film; adopts a fully mechanical mechanism, without corresponding components such as motors and cylinders, has reliable operation, increased service life, and reduced operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a front structural schematic diagram of the utility model;

[0014] Figure 2 It is a schematic diagram of the axonometric structure of the utility model;

[0015] Figure 3 It is a left-side axonometric structural schematic diagram of the utility model;

[0016] Figure 4 yes Figure 3 A schematic diagram of the local enlarged structure at point A in the middle;

[0017] Figure 5 It is a schematic diagram of the structure of the connecting rod and brake assembly;

[0018] Figure 6 This is a schematic diagram of the structure of the frame, film placing shaft, brake disc, code disc mark, bracket, speed meter and contact switch.

[0019] Markings in the attached figure: 1. Frame; 2. Film-collecting shaft; 3. Film-releasing shaft; 4. Driving motor; 5. Brake disc; 6. Shaft; 7. Connecting rod; 8. Pressure roller; 9. Brake assembly; 10. Mounting pin; 11. Brake pad mounting plate; 12. Brake pad; 13. Long slide groove; 14. Locking nut; 15. Spring sheet; 16. Latch; 17. Adjustment plate; 18. Shock absorber; 19. Spring; 20. Code disk mark; 21. Bracket; 22. Speed ​​meter; 23. Contact switch. DETAILED DESCRIPTION

[0020] In order to facilitate the understanding of the utility model, the utility model will be described more comprehensively below with reference to the relevant drawings. The utility model can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the utility model more thorough and comprehensive. Example 1

[0021] like Figures 1 to 3As shown, an auxiliary film feeding mechanism of a packaging machine includes a frame 1, a film-collecting shaft 2 and a film-releasing shaft 3, the film-collecting shaft 2 and the film-releasing shaft 3 are rotatably mounted on the frame 1 through a rotating shaft, the film-collecting shaft 2 rewinds the packaging film, and the film-releasing shaft 3 releases the packaging film; it also includes a driving motor 4, a brake disc 5, an axle rod 6, a connecting rod 7, a pressure roller 8 and a brake assembly 9, the driving motor 4 is mounted on the frame 1, the output shaft of the driving motor 4 is transmission-connected with the film-collecting shaft 2, the brake disc 5 is concentrically mounted on the rotating shaft of the film-releasing shaft 3, the axle rod 6 is mounted on the frame 1, the axle rod 6 is located below the film-releasing shaft 3, the middle part of the connecting rod 7 is rotationally connected with the axle rod 6, the pressure roller 8 is rotationally mounted on the right end of the connecting rod 7, the pressure roller 8 is located above the packaging film between the film-collecting shaft 2 and the film-releasing shaft 3, the brake assembly 9 is mounted on the left end of the connecting rod 7, and the brake assembly 9 is matched and aligned with the brake disc 5; the brake assembly 9 includes a mounting pin 10, a brake pad mounting plate 11 and a brake pad 12, the mounting pin 10 is installed on the left end of the connecting rod 7, the lower end of the brake pad mounting plate 11 is connected to the mounting pin 10, and the brake pad 12 is installed on the side of the brake pad mounting plate 11 facing the brake disc 5; it also includes a long slide groove 13 and a locking nut 14, a long slide groove 13 is set on the right end of the connecting rod 7, the central axis of the pressure roller 8 is inserted into the long slide groove 13, and the locking nut 14 is rotatably screwed on the central axis of Su Sohu to lock the pressure roller 8 on the connecting rod 7; it also includes a shock absorber 18 and a spring 19, the lower end of the shock absorber 18 is rotatably connected to the frame 1, the upper end of the shock absorber 18 is connected to the connecting rod 7, and the shock absorber 18 is provided with a spring 19, and the tension of the spring 19 pulls the right end of the connecting rod 7 downward.

[0022] After adjusting the angle and distance between the brake pad 12 and the brake disc 5, the brake pad mounting plate 11 and the mounting pin 10 are locked and fixed, the position of the pressure roller 8 is adjusted along the long slide groove 13, and the locking nut 14 is tightened to lock it, and the distance between the pressure roller 8 and the shaft rod 6 is adjusted to adjust the length of the force arm, and then the friction between the brake pad 12 and the brake disc 5 is adjusted. The shock absorber 18 and the spring 19 pull the right end of the connecting rod 7 and the pressure roller 8 downward, so that the pressure roller 8 presses down the packaging film between the film collecting shaft 2 and the film releasing shaft 3. By adjusting The elastic force of the spring 19 adjusts the tension on the packaging film, and can also adjust the pressing force between the brake pad 12 and the brake disc 5. During operation, the packaging film roll is loaded on the film-releasing shaft 3, and the packaging film is drawn out from the packaging film roll and rolled up on the film-receiving shaft 2. During film feeding, the driving motor 4 drives the film-receiving shaft 2 to rotate, and the film-receiving shaft 2 rewinds and tightens the packaging film, so that the packaging film between the film-receiving shaft 2 and the film-releasing shaft 3 is stretched and straightened, so that the packaging film lifts the pressure roller 8, and the pressure roller 8 drives the right end of the connecting rod 7 to rotate upward around the shaft 6. When the driving motor 4 stops, the film collecting shaft 2 stops rotating, and the gravity of the pressure roller 8 presses the packaging film between the film collecting shaft 2 and the film discharging shaft 3 downward for a distance again, so that the pressure roller 8 drives the right end of the connecting rod 7 to rotate downward around the shaft 6, so that the left end of the connecting rod 7 drives the brake assembly 9 to rotate downward and contact with the brake disc 5 frictionally, so as to stop the film discharging shaft 3. The single motor design reduces the equipment cost, does not require a special packaging film tensioning system and sensor, simplifies the structure, reduces the failure rate, and realizes the smooth operation of the auxiliary film feeding of the packaging film; adopts a full mechanical mechanism, without corresponding components such as motor cylinders, reliable operation, improved service life, and reduced operation cost. Example 2

[0023] like Figure 4 and Figure 5 As shown, on the basis of Example 2, it also includes a spring sheet 15 and a latch 16, the brake pad mounting plate 11 is movably connected to the mounting pin 10, the upper end of the spring sheet 15 is rotatably connected to the brake pad mounting plate 11, and the lower end of the spring sheet 15 is connected to the left end of the connecting rod 7 through the latch 16; it also includes an adjustment plate 17, the adjustment plate 17 is installed at the left end of the connecting rod 7, and a plurality of insertion holes for the latch 16 are arranged on the adjustment plate 17, and the plurality of insertion holes are vertically arranged.

[0024] When the brake pad 12 is pressed against the brake disc 5 and the pressure roller 8 continues to descend, the left end of the connecting rod 7 compresses the spring sheet 15 upward through the latch 16, so that the pressure roller 8 can always tighten the packaging film downward to prevent the packaging film from loosening. The insertion hole of the latch 16 on the adjustment plate 17 is adjusted to adjust the angle between the brake pad mounting plate 11 and the connecting rod 7, thereby adjusting the friction pressing force between the brake pad 12 and the brake disc 5. Example 3

[0025] like Figure 4 and Figure 6 As shown, on the basis of Example 2, it also includes multiple code disk marks 20, a bracket 21, a speed meter 22 and a contact switch 23. Multiple code disk marks 20 are evenly arranged on the circumference of the brake disk 5. The bracket 21 is installed on the shaft 6. The speed meter 22 is installed on the bracket 21. The speed meter 22 is aligned with the code disk mark 20. The contact switch 23 is installed on the bracket 21. The contact arm of the contact switch 23 is aligned with the brake pad 12.

[0026] When the brake disc 5 rotates, multiple code disc marks 20 are driven to rotate. The speed meter 22 measures the rotation speed of the brake disc 5 by detecting the time the code disc mark 20 passes. When the brake pad 12 approaches the brake disc 5, the contact arm of the contact switch 23 is pushed by the brake pad 12 to generate a signal, and the moment one when the signal is generated and the moment two when the brake disc 5 stops rotating are recorded. The time difference between the moment two and the moment one is the braking time of the brake pad 12 on the brake disc 5. When the braking time is too long, the relative distance between the brake pad 12 and the brake disc 5 is adjusted by adjusting the installation position of the plug-in hole of the latch 16 on the adjusting plate 17, so as to detect the film running state and the braking effect of the packaging film and improve practicality.

[0027] like Figures 1 to 6The film-feeding mechanism of the packaging machine is shown in the figure. When it is working, the packaging film roll is first loaded on the film-feeding shaft 3, and the packaging film is drawn out from the packaging film roll and then rolled up on the film-receiving shaft 2. When the film is fed, the driving motor 4 drives the film-receiving shaft 2 to rotate, and the film-receiving shaft 2 reels and tightens the packaging film, so that the packaging film between the film-receiving shaft 2 and the film-feeding shaft 3 is stretched and straightened, so that the packaging film lifts the pressure roller 8, and then the pressure roller 8 drives the right end of the connecting rod 7 to rotate upward around the shaft rod 6, so that the left end of the connecting rod 7 drives the brake pad 12 to rotate downward through the brake pad mounting plate 11 and disengage from the brake disc 5, so that the film-feeding shaft 3 can rotate freely, so that the packaging film can be smoothly drawn out. At this time, the gravity of the pressure roller 8 and the elastic force of the spring 19 act on the packaging film between the film-receiving shaft 2 and the film-feeding shaft 3, pressing the packaging film downward and tightening it. Then, when the driving motor 4 stops, the film-receiving shaft 2 stops rotating, and the spring The elastic force of 19 and the gravity of the pressure roller 8 press the packaging film between the film collecting shaft 2 and the film releasing shaft 3 downward for a distance again, so that the pressure roller 8 drives the right end of the connecting rod 7 to rotate downward around the shaft 6, so that the left end of the connecting rod 7 drives the brake pad 12 to rotate downward through the brake pad mounting plate 11 and frictionally contact with the brake disc 5 to achieve the braking of the film releasing shaft 3. At the same time, when the brake pad 12 approaches the brake disc 5, the contact arm of the contact switch 23 is pushed by the brake pad 12 to generate a signal, and the time one when the signal is generated and the time two when the brake disc 5 stops rotating are recorded. The time difference between the time two and the time one is the braking time of the brake pad 12 on the brake disc 5. Finally, when the braking time is too long, the insertion hole of the pin 16 on the adjusting plate 17 is adjusted to adjust the angle between the brake pad mounting plate 11 and the connecting rod 7, thereby adjusting the friction pressing force between the brake pad 12 and the brake disc 5.

[0028] The main functions achieved by this utility model are:

[0029] 1. Single motor design is adopted, no special tensioning system and sensor are required, which reduces the failure rate, equipment cost and operating cost;

[0030] 2. It adopts a fully mechanical mechanism without corresponding components such as motors and cylinders, which ensures reliable operation and increases service life;

[0031] 3. Ability to adjust brake friction;

[0032] 4. It can detect the film movement status and braking effect of the packaging film.

[0033] The utility model is an auxiliary film-feeding mechanism for a packaging machine, and its installation method, connection method or setting method are all common mechanical methods, and can be implemented as long as they can achieve their beneficial effects; the frame 1, film-collecting shaft 2, film-releasing shaft 3, driving motor 4, brake disc 5, shaft rod 6, pressure roller 8, brake assembly 9, brake pad mounting plate 11, brake pad 12, locking nut 14, spring sheet 15, pin 16, shock absorber 18, spring 19, code disk mark 20, speed meter 22, and contact switch 23 of the auxiliary film-feeding mechanism for a packaging machine of the utility model are purchased on the market, and technical personnel in the industry only need to install and operate them according to the accompanying instruction manual, without the need for technical personnel in this field to pay creative labor.

[0034] All technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0035] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. An auxiliary film feeding mechanism of a packaging machine, comprising a frame (1), a film collecting shaft (2) and a film releasing shaft (3), wherein the film collecting shaft (2) and the film releasing shaft (3) are rotatably mounted on the frame (1) via rotating shafts, respectively, the film collecting shaft (2) rewinds the packaging film, and the film releasing shaft (3) releases the packaging film; characterized in that: The machine also comprises a driving motor (4), a brake disc (5), a shaft (6), a connecting rod (7), a pressure roller (8) and a brake assembly (9), wherein the driving motor (4) is mounted on the frame (1), the output shaft of the driving motor (4) is drivingly connected to the film collecting shaft (2), the brake disc (5) is coaxially mounted on the rotating shaft of the film unwinding shaft (3), the shaft (6) is mounted on the frame (1), the shaft (6) is located below the film unwinding shaft (3), the middle part of the connecting rod (7) is rotatably connected to the shaft (6), the pressure roller (8) is rotatably mounted on the right end of the connecting rod (7), the pressure roller (8) is located above the packaging film between the film collecting shaft (2) and the film unwinding shaft (3), the brake assembly (9) is mounted on the left end of the connecting rod (7), and the brake assembly (9) is matched and aligned with the brake disc (5).

2. The auxiliary film-feeding mechanism of a packaging machine as claimed in claim 1, characterized in that: The brake assembly (9) comprises a mounting pin (10), a brake pad mounting plate (11) and a brake pad (12), wherein the mounting pin (10) is mounted on the left end of the connecting rod (7), the lower end of the brake pad mounting plate (11) is connected to the mounting pin (10), and the brake pad (12) is mounted on the side of the brake pad mounting plate (11) facing the brake disc (5).

3. The auxiliary film-feeding mechanism of a packaging machine as claimed in claim 1, characterized in that: It also includes a long slide groove (13) and a locking nut (14). The long slide groove (13) is set on the right end of the connecting rod (7), the central axis of the pressure roller (8) is inserted into the long slide groove (13), and the locking nut (14) is rotatably screwed on the central axis of Su Sohu to lock the pressure roller (8) on the connecting rod (7).

4. The auxiliary film-feeding mechanism of a packaging machine as claimed in claim 2, characterized in that: It also includes a spring sheet (15) and a latch (16), the brake pad mounting plate (11) is movably connected to the mounting pin (10), the upper end of the spring sheet (15) is rotatably connected to the brake pad mounting plate (11), and the lower end of the spring sheet (15) is connected to the left end of the connecting rod (7) through the latch (16).

5. The auxiliary film-feeding mechanism of a packaging machine as claimed in claim 4, characterized in that: It also includes an adjustment plate (17), which is mounted on the left end of the connecting rod (7), and a plurality of insertion holes for the latch pins (16) are arranged on the adjustment plate (17), wherein the plurality of insertion holes are arranged vertically.

6. The auxiliary film-feeding mechanism of a packaging machine as claimed in claim 1, characterized in that: The invention also comprises a shock absorber (18) and a spring (19), wherein the lower end of the shock absorber (18) is rotatably connected to the frame (1), the upper end of the shock absorber (18) is connected to the connecting rod (7), and the spring (19) is sleeved on the shock absorber (18), and the tension of the spring (19) pulls the right end of the connecting rod (7) downward.

7. The auxiliary film-feeding mechanism of a packaging machine as claimed in claim 2, characterized in that: The invention also comprises a plurality of code disc marks (20), a bracket (21), a speed meter (22) and a contact switch (23), wherein a plurality of code disc marks (20) are evenly arranged on the circumference of the brake disc (5), the bracket (21) is mounted on the shaft (6), the speed meter (22) is mounted on the bracket (21), the speed meter (22) is aligned with the code disc mark (20), the contact switch (23) is mounted on the bracket (21), and the contact arm of the contact switch (23) is aligned with the brake pad (12).

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