A plate feeding mechanism for processing prop display counters

Abstract

The present invention relates to the field of conveyors, and in particular to a plate feeding mechanism for processing prop display counters, comprising a chain plate conveyor belt, a plurality of concave supports are evenly distributed and fixedly installed on the chain plates of the chain plate conveyor belt, both ends of the concave supports are penetrated and rotatably installed with a flip shaft, a limited plate frame is fixedly installed between the opposite ends of the two flip shafts, and the opposite ends of the two flip shafts are coaxially inlaid with a No. 1 flip gear, and the No. 1 flip gear is meshed with a No. 1 flip tooth plate, and the No. 1 flip tooth plate is elastically connected to the concave support, and the upper end of the chain plate conveyor belt is symmetrically installed with two horizontal rails, and both ends of the horizontal rails are extended with inclined rails. The present invention reduces the labor intensity of workers, improves the convenience of feeding, and also ensures the normal feeding of the plate, while ensuring the comprehensive painting of the plate.

Description

Technical Field

[0001] The invention relates to the field of conveyors, and in particular to a plate feeding mechanism for processing a prop display counter. Background Art

[0002] Display cabinets are protective display tables for displaying goods. Display cabinets are widely used in industries such as handicrafts, gifts, jewelry, mobile phones, glasses, watches, tobacco, alcohol, and cosmetics. During the processing of prop display cabinets, in order to improve the aesthetics, it is often necessary to spray paint the panels of the counter. However, after the existing conveyor conveys the panels to the painting station to paint one side of the panels, and then conveys them to the next painting station to paint the other side of the panels, workers are required to manually turn the panels over so that they are exposed facing upwards, and then paint the other side. The operation process is quite cumbersome, which increases the labor intensity of the workers and affects the convenience of loading. Summary of the invention

[0003] The purpose of the present invention is to solve the shortcomings existing in the background technology and to propose a plate feeding mechanism for processing a prop display counter.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is: a plate feeding mechanism for processing prop display counters, including a chain plate conveyor belt, a plurality of concave supports are evenly distributed and fixedly installed on the chain plates of the chain plate conveyor belt, both ends of the concave supports are penetrated and rotatably installed with a turning shaft, a limited plate frame is fixedly installed between the opposite ends of the two turning shafts, the opposite ends of the two turning shafts are coaxially inlaid with a No. 1 turning gear, a No. 1 turning gear is meshed with a No. 1 turning tooth plate, the No. 1 turning tooth plate is elastically connected to the concave supports, and two horizontal Track, both ends of the horizontal track are extended with inclined tracks, the lower end of the No. 1 flip tooth plate is connected with a guide wheel, the guide wheel corresponds to the horizontal track, two groups of flip rods are provided on both sides of the limit plate frame, the number of flip rods in each group is two, both ends of the flip rod are coaxially inlaid with fixed sleeves, the outer surface of the fixed sleeve is fixedly installed with a supporting plate ear, the end of the supporting plate ear is fixedly installed with a supporting thorn, the middle part of the outer surface of the flip rod is coaxially inlaid with a No. 2 flip gear, the outer side of the No. 2 flip gear is meshed with a No. 2 flip tooth plate, and the No. 2 flip tooth plate is elastically connected to the limit plate frame.

[0005] Preferably, a plate-taking groove is provided in the middle of the upper end of the plate-limiting frame, an extension frame is fixedly installed at the upper edge of the front end of the concave support, two guide rods are symmetrically installed through the end of the extension frame, the guide rods are slidably matched with the extension frame, and a connecting seat is fixedly installed at the lower ends of the two guide rods, and the connecting seat is fixed to the No. 1 flip tooth plate.

[0006] Preferably, a return spring is wound around the outer side of the guide rod, the lower end of the return spring is fixed to the upper end of the connecting seat, the upper end of the return spring is fixed to the lower end of the extension frame, the upper end of the guide rod is coaxially inlaid with a limiting cap, the limiting cap is fitted to the upper end surface of the extension frame, and a support frame is fixedly installed at the lower end of the frame of the chain conveyor belt.

[0007] Preferably, the horizontal track and the inclined track are formed integrally.

[0008] Preferably, two track frames are symmetrically fixedly installed at the lower end of the horizontal track, the ends of the track frames are fixed to the frame of the chain conveyor belt, the lower end of the No. 1 flip tooth plate is fixedly installed with a wheel frame, the guide wheel is located on the inner side of the wheel frame, the interior of the wheel frame is rotatably installed with a wheel axle, and the guide wheel is embedded in the outer surface of the wheel axle.

[0009] Preferably, rod sleeves are provided on the front and rear sides of the No. 2 flip gear, the flip rod passes through and is rotatably installed in the interior of the rod sleeve, a fixing sleeve ear is fixedly installed on the outer surface of the rod sleeve, the end of the fixing sleeve ear is fixed to the limiting plate frame, an L-shaped frame is fixedly installed on the outer surface of the rod sleeve, the L-shaped frame is opposite to the fixing sleeve ear, a guide sleeve is fixedly installed on the end of the L-shaped frame, a square top rod is fittedly installed inside the guide sleeve, two ends of the square top rod pass through the two sides of the guide sleeve, one end of the square top rod is fixedly installed with a limiting ear, and the limiting ear is fixed to the No. 2 flip gear plate.

[0010] Preferably, a tensioning spring is wound around the outer side of the square push rod, one end of the tensioning spring is fixed to the guide sleeve, and a connecting plate is fixedly installed on the other end of the square push rod, and the other end of the tensioning spring is fixed to the connecting plate, and two protruding ears extend symmetrically from the side of the connecting plate, and a connecting shaft is rotatably installed between the ends of the two protruding ears, and a top wheel is coaxially installed on the outer surface of the connecting shaft, and a pushing ring rail is coaxially arranged on the outer side of the flip shaft, and a ring frame is fixedly installed on the inner bottom surface of the pushing ring rail, and the end of the ring frame is fixed to a concave support, and the top wheel fits on the pushing ring rail, and the upper part of the side surface of the pushing ring rail is lower than the lower part of the side surface of the pushing ring rail, and the upper and lower parts of the side surface of the pushing ring rail are transitioned by an inclined surface.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. When the chain plate conveyor belt drives the plate limit frame to move to the inclined track, the guide wheel will roll on the inclined track to drive the No. 1 flip tooth plate to move up, and then drive the No. 1 flip gear to rotate, so that the plate limit frame can be flipped to turn the plate in the plate limit frame over. After turning over, the guide wheel just moves to the horizontal track, and then the chain plate conveyor belt continues to drive the plate limit frame to move. At this time, the guide wheel rolls on the horizontal track, so that the plate always remains in the turned-over state to be painted, so as to achieve the purpose of painting both sides of the plate. The process does not require workers to manually turn the material, which effectively reduces the labor intensity of workers and improves the convenience of loading.

[0013] 2. When the plate limit frame is in the process of flipping, the top wheel originally on the top will roll from the upper part of the pushing ring rail to the lower part, so as to push the upper square push rod during the rolling process, so that the No. 2 flipping tooth plate can move, and then drive the No. 2 flipping gear to rotate, so that the upper flip rod can rotate, so as to flip the upper support plate ear down to support the plate, so that the plate will not fall after flipping, thereby ensuring the normal loading of the plate. At the same time, the top wheel originally on the bottom will roll from the lower part of the pushing ring rail to the upper part. In this process, the tightening spring will push the lower square push rod, so that the No. 2 flipping tooth plate moves, and then drives the No. 2 flipping gear to rotate, so that the lower flip rod can rotate, so as to flip up the lower support plate ear to break away from the top of the plate, so that it will not be blocked by the support plate ear during the subsequent painting process, thereby ensuring the comprehensive painting of the plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of a plate feeding mechanism for processing a prop display counter according to the present invention;

[0015] Figure 2 It is a schematic diagram of a plate limit frame of a plate feeding mechanism for processing a prop display counter according to the present invention;

[0016] Figure 3 The present invention is a plate feeding mechanism for processing a prop display counter Figure 2 A magnified view of middle;

[0017] Figure 4 It is a schematic diagram of a flip rod of a plate feeding mechanism for processing a prop display counter according to the present invention;

[0018] Figure 5 It is a schematic diagram of the turning axis of a plate feeding mechanism for processing a prop display counter according to the present invention;

[0019] Figure 6 The present invention is a plate feeding mechanism for processing a prop display counter Figure 5 Enlarged view of middle B;

[0020] Figure 7The present invention is a schematic diagram of a driving ring rail of a plate feeding mechanism for processing a prop display counter.

[0021] In the figure: 1, chain conveyor belt; 2, horizontal track; 3, inclined track; 4, track frame; 5, wheel frame; 6, plate limit frame; 7, concave support; 8, flip shaft; 9, plate taking slot; 10, flip rod; 11, push ring rail; 12, extension frame; 13, limit cap; 14, reset spring; 15, guide rod; 16, connecting seat; 17, guide wheel; 18, wheel axle; 19, No. 1 flip tooth plate; 20 1. Flip gear No. 1; 21. Flip gear No. 2; 22. Fixed sleeve; 23. Support plate ear; 24. Support thorn; 25. L-shaped frame; 26. Square push rod; 27. Fixed sleeve ear; 28. Guide sleeve; 29. ​​Tightening spring; 30. Connecting plate; 31. Extending ear; 32. Connecting shaft; 33. Top wheel; 34. Flip gear No. 2; 35. Limiting ear; 36. Support frame; 37. Rod sleeve; 38. Ring frame. DETAILED DESCRIPTION

[0022] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0023] like Figure 1-Figure 7 The shown plate feeding mechanism for processing a prop display counter comprises a chain conveyor belt 1, on the chain plate of which a plurality of concave supports 7 are evenly distributed and fixedly installed, the concave supports 7 play a role in supporting a plate limit frame 6, both ends of the concave supports 7 are penetrated by a turning shaft 8 rotatably installed, the plate limit frame 6 is fixedly installed between the opposite ends of the two turning shafts 8, the turning shaft 8 plays a role in turning the plate limit frame 6, the opposite ends of the two turning shafts 8 are coaxially inlaid with a No. 1 turning gear 20, the No. 1 turning gear 20 is meshed with a No. 1 turning tooth plate 19, the cooperation between the No. 1 turning gear 20 and the No. 1 turning tooth plate 19 plays a role in rotating the turning shaft 8, and the No. 1 turning tooth plate 19 is elastically connected to the concave supports 7.

[0024] A plate taking groove 9 is provided in the middle of the upper end of the plate limiting frame 6. The plate taking groove 9 serves to facilitate the taking and placing of the plate into the plate limiting frame 6. An extension frame 12 is fixedly installed at the upper edge of the front end of the concave support 7. The extension frame 12 serves to carry the guide rod 15. Two guide rods 15 are symmetrically installed through the ends of the extension frame 12. The guide rod 15 serves to guide the No. 1 flip tooth plate 19. The guide rod 15 slides with the extension frame 12. A connecting seat 16 is fixedly installed at the lower ends of the two guide rods 15. The connecting seat 16 serves to connect, and the connecting seat 16 is fixed to the No. 1 flip tooth plate 19.

[0025] A return spring 14 is wound around the outer side of the guide rod 15, and the lower end of the return spring 14 is fixed to the upper end of the connecting seat 16. The return spring 14 plays a role in restoring the plate after flipping. The upper end of the return spring 14 is fixed to the lower end of the extension frame 12. The upper end of the guide rod 15 is coaxially inlaid with a limiting cap 13, and the limiting cap 13 is attached to the upper end surface of the extension frame 12. The limiting cap 13 plays a role in limiting the downward movement height of the No. 1 flip tooth plate 19. A support frame 36 is fixedly installed at the lower end of the frame of the chain conveyor belt 1, and the support frame 36 plays a role in supporting the chain conveyor belt 1.

[0026] Two horizontal rails 2 are symmetrically installed at the upper end of the chain conveyor belt 1. The guide wheel 17 rolls on the horizontal rail 2 to keep the plate in the turned-over state for painting. Inclined rails 3 are extended at both ends of the horizontal rail 2. The horizontal rail 2 and the inclined rail 3 are integrally formed. The guide wheel 17 will roll on the inclined rail 3 to drive the No. 1 flip tooth plate 19 to move up, and then drive the No. 1 flip gear 20 to rotate, so that the limit plate frame 6 can be flipped to turn the plate in the limit plate frame 6. The lower end of the No. 1 flip tooth plate 19 is connected to the guide wheel 17. The guide wheel 17 plays a role in rolling to reduce wear. The guide wheel 17 corresponds to the horizontal rail 2.

[0027] Two track frames 4 are symmetrically fixedly installed at the lower end of the horizontal track 2. The ends of the track frames 4 are fixed to the frame of the chain conveyor belt 1. The track frames 4 fix the horizontal track 2. A wheel frame 5 is fixedly installed at the lower end of the No. 1 flip tooth plate 19. The wheel frame 5 supports the guide wheel 17. The guide wheel 17 is located on the inner side of the wheel frame 5. A wheel axle 18 is rotatably installed inside the wheel frame 5. The wheel axle 18 connects the guide wheel 17. The guide wheel 17 is embedded in the outer surface of the wheel axle 18.

[0028] Two groups of flip rods 10 are provided on both sides of the limit plate frame 6, and the number of flip rods 10 in each group is two. Both ends of the flip rod 10 are coaxially inlaid with a fixing sleeve 22, and the flip rod 10 plays a role in driving the support plate ear 23 to flip. The outer surface of the fixing sleeve 22 is fixedly installed with the support plate ear 23, and the fixing sleeve 22 plays a role in fixing the support plate ear 23. The end of the support plate ear 23 is fixedly installed with a supporting thorn 24, and the supporting thorn 24 can reduce the contact area with the plate to avoid affecting the paint surface after painting. The middle part of the outer surface of the flip rod 10 is coaxially inlaid with a No. 2 flip gear 21, and the No. 2 flip gear 21 and the No. 2 flip tooth plate 34 play a role in allowing the flip rod 10 to rotate. The outer side of the No. 2 flip gear 21 is meshed with the No. 2 flip tooth plate 34, and the No. 2 flip tooth plate 34 is elastically connected to the limit plate frame 6.

[0029] Rod sleeves 37 are provided at the front and rear of the second flip gear 21. The flip rod 10 is rotatably installed inside the rod sleeve 37. The rod sleeve 37 serves to connect the flip rod 10. A fixed sleeve ear 27 is fixedly installed on the outer surface of the rod sleeve 37. The fixed sleeve ear 27 serves to fix the rod sleeve 37. The end of the fixed sleeve ear 27 is fixed to the limit plate frame 6. An L-shaped frame 25 is fixedly installed on the outer surface of the rod sleeve 37. The L-shaped frame 25 is opposite to the fixed sleeve ear 27. A guide sleeve 28 is fixedly installed on the end of the L-shaped frame 25. The L-shaped frame 25 serves to fix the guide sleeve 28. A square push rod 26 is fitted inside the guide sleeve 28. Both ends of the square push rod 26 extend through both sides of the guide sleeve 28. The guide sleeve 28 and the square push rod 26 serve to guide the second flip tooth plate 34. A limiting ear 35 is fixedly installed at one end of the square push rod 26. The limiting ear 35 serves to prevent the guide sleeve 28 and the square push rod 26 from separating. The limiting ear 35 also serves to connect. The limiting ear 35 is fixed to the second flip tooth plate 34.

[0030] A tensioning spring 29 is wound around the outer side of the square push rod 26, and one end of the tensioning spring 29 is fixed to the guide sleeve 28. The tensioning spring 29 plays a role in keeping the top wheel 33 and the pushing ring rail 11 in contact at all times. A connecting plate 30 is fixedly installed on the other end of the square push rod 26, and the connecting plate 30 plays a role in bearing the protruding ear 31. The other end of the tensioning spring 29 is fixed to the connecting plate 30. Two protruding ears 31 extend symmetrically from the side of the connecting plate 30, and a connecting shaft 32 is rotatably installed between the ends of the two protruding ears 31. A top wheel 33 is coaxially installed on the outer surface of the connecting shaft 32, and the connecting shaft 32 plays the role of connecting the top wheel 33. The pushing ring rail 11 is coaxially arranged on the outer side of the flip shaft 8, and a ring frame 38 is fixedly installed on the inner bottom surface of the pushing ring rail 11. The end of the ring frame 38 is fixed to the concave support 7, and the ring frame 38 plays a role in fixing the pushing ring rail 11, and the top wheel 33 fits on the pushing ring rail 11 The upper side of the push ring rail 11 is lower than the lower side of the push ring rail 11, and the upper and lower sides of the push ring rail 11 are transitioned by an inclined plane. When the limit plate frame 6 is in the process of turning over, the top wheel 33 originally at the top will roll from the upper part of the push ring rail 11 to the lower part, so as to push the upper square push rod 26 during the rolling process, so that the No. 2 turning gear plate 34 can move, thereby driving the No. 2 turning gear 21 to rotate, so that the upper turning rod 10 can rotate, so as to flip the upper supporting plate ear 23 down to support the plate, so that the plate will not fall after turning over. At the same time, the top wheel 33 originally at the bottom will roll from the lower part of the push ring rail 11 to the upper part, and in this process, the tightening spring 29 will push the lower square push rod 26, so that the No. 2 turning gear plate 34 moves, thereby driving the No. 2 turning gear 21 to rotate, so that the lower turning rod 10 can rotate, so as to flip up the lower supporting plate ear 23 to separate from the top of the plate.

[0031] When loading, the plate is placed in the plate limit frame 6. At this time, the four sides of the plate are in contact with the inner surface of the plate limit frame 6, and the supporting plate ears 23 below support the plate. Then the chain plate conveyor belt 1 works to drive the plate on the plate limit frame 6 to move to the painting station to spray paint the upper end surface of the plate. Then the chain plate conveyor belt 1 continues to work to drive the plate on the plate limit frame 6 to move to the inclined track 3. At this time, the guide wheel 17 will roll in contact with the inclined track 3 to drive the No. 1 flip tooth plate 19 to move up, thereby driving the No. 1 flip gear 20 to rotate, so that the plate limit frame 6 can be flipped to turn the plate in the plate limit frame 6 over. When the plate limit frame 6 is in the process of flipping, the top wheel 33 originally on the top will roll from the upper part of the push ring rail 11 to the lower part, so as to push the upper square top rod 26 during the rolling process, so that the No. 2 flip tooth plate 34 can move, thereby driving the No. 2 flip gear 2 1 is rotated to allow the upper flip rod 10 to rotate, so as to flip down the upper support plate ear 23 to support the plate, so that the plate will not fall after turning over. At the same time, the top wheel 33 originally at the bottom will roll from the lower part of the push ring rail 11 to the upper part. In this process, the tightening spring 29 will push the lower square push rod 26 to move the No. 2 flip gear plate 34, thereby driving the No. 2 flip gear 21 to rotate, so that the lower flip rod 10 can rotate to flip up the lower support plate ear 23 to break away from the top of the plate. When the plate is turned over, the guide wheel 17 just moves to the horizontal track 2, and then the chain plate conveyor belt 1 continues to drive the plate limit frame 6 to move. At this time, the guide wheel 17 rolls on the horizontal track 2, so that the plate always keeps the turned-over state and moves to the painting station to spray paint on the lower end surface of the plate, so as to load the material and complete the painting operation on both sides of the plate.

[0032] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A plate feeding mechanism for processing a prop display counter, comprising a chain conveyor belt (1), characterized in that: A plurality of concave supports (7) are evenly distributed and fixedly installed on the chain plates of the chain conveyor belt (1), and a turning shaft (8) is rotatably installed on both ends of the concave supports (7). A limited plate frame (6) is fixedly installed between the opposite ends of the two turning shafts (8), and a first turning gear (20) is coaxially inlaid on the opposite ends of the two turning shafts (8). A first turning gear (20) is meshed with a first turning tooth plate (19), and the first turning tooth plate (19) is elastically connected to the concave supports (7). Two horizontal rails (2) are symmetrically installed on the upper end of the chain conveyor belt (1), and inclined rails (3) are extended at both ends of the horizontal rails (2). The first turning tooth plate (19) The lower end of the guide wheel (17) is connected to the horizontal track (2), and the guide wheel (17) corresponds to the horizontal track (2). Two groups of flip rods (10) are provided on both sides of the limit plate frame (6), and the number of flip rods (10) in each group is two. Both ends of the flip rod (10) are coaxially inlaid with fixed sleeves (22), and the outer surface of the fixed sleeve (22) is fixedly installed with a supporting plate ear (23), and the end of the supporting plate ear (23) is fixedly installed with a supporting thorn (24). The middle part of the outer surface of the flip rod (10) is coaxially inlaid with a second flip gear (21), and the outer side of the second flip gear (21) is meshed with a second flip tooth plate (34), and the second flip tooth plate (34) is elastically connected to the limit plate frame (6); A plate taking groove (9) is provided in the middle of the upper end of the plate limiting frame (6); a protruding frame (12) is fixedly installed at the upper edge of the front end of the concave support (7); two guide rods (15) are symmetrically installed through the ends of the protruding frame (12); the guide rods (15) are slidably matched with the protruding frame (12); a connecting seat (16) is fixedly installed at the lower ends of the two guide rods (15); the connecting seat (16) is fixed to the first flip tooth plate (19); A rod sleeve (37) is provided at the front and rear sides of the second flip gear (21); the flip rod (10) is rotatably mounted inside the rod sleeve (37); a fixed sleeve ear (27) is fixedly mounted on the outer surface of the rod sleeve (37); an end of the fixed sleeve ear (27) is fixed to the limit plate frame (6); an L-shaped frame (25) is fixedly mounted on the outer surface of the rod sleeve (37); the L-shaped frame (25) and the fixed sleeve ear (27) are arranged opposite to each other; a guide sleeve (28) is fixedly mounted on the end of the L-shaped frame (25); a square push rod (26) is fitted inside the guide sleeve (28); two ends of the square push rod (26) extend out from two sides of the guide sleeve (28); a limiting ear (35) is fixedly mounted on one end of the square push rod (26); and the limiting ear (35) is fixed to the second flip gear plate (34).

2. A plate feeding mechanism for processing a prop display counter according to claim 1, characterized in that: A return spring (14) is wound around the outer side of the guide rod (15), the lower end of the return spring (14) is fixed to the upper end of the connecting seat (16), the upper end of the return spring (14) is fixed to the lower end of the extension frame (12), the upper end of the guide rod (15) is coaxially inlaid with a limit cap (13), the limit cap (13) is attached to the upper end surface of the extension frame (12), and a support frame (36) is fixedly installed at the lower end of the frame of the chain conveyor belt (1).

3. A plate feeding mechanism for processing a prop display counter according to claim 1, characterized in that: The horizontal track (2) and the inclined track (3) are integrally formed.

4. A plate feeding mechanism for processing a prop display counter according to claim 3, characterized in that: Two track frames (4) are symmetrically fixedly installed at the lower end of the horizontal track (2), the ends of the track frames (4) are fixed to the frame of the chain plate conveyor belt (1), and a wheel frame (5) is fixedly installed at the lower end of the No. 1 flip tooth plate (19), the guide wheel (17) is located on the inner side of the wheel frame (5), and a wheel axle (18) is rotatably installed inside the wheel frame (5), and the guide wheel (17) is embedded in the outer surface of the wheel axle (18).

5. The plate feeding mechanism for processing a prop display counter according to claim 1, characterized in that: A tensioning spring (29) is wound around the outer side of the square push rod (26), one end of the tensioning spring (29) is fixed to the guide sleeve (28), and a connecting plate (30) is fixedly installed on the other end of the square push rod (26), and the other end of the tensioning spring (29) is fixed to the connecting plate (30), and two protruding ears (31) are symmetrically extended from the side of the connecting plate (30), and a connecting shaft (32) is rotatably installed between the ends of the two protruding ears (31), and the connecting shaft (32) ) is coaxially mounted on the outer surface of the turning shaft (8), a driving ring rail (11) is coaxially mounted on the outer side of the turning shaft (8), a ring frame (38) is fixedly mounted on the inner bottom surface of the driving ring rail (11), an end of the ring frame (38) is fixed to the concave support (7), the top wheel (33) is fitted on the driving ring rail (11), an upper side surface of the driving ring rail (11) is lower than a lower side surface of the driving ring rail (11), and an inclined surface transition is formed between the upper and lower sides of the driving ring rail (11).

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