Foot pad hemming equipment and edge sealing method

Abstract

The invention belongs to the field of sewing equipment, and particularly relates to foot pad hemming equipment and an edge banding method.The foot pad hemming equipment comprises a workbench and a sewing machine, the sewing machine is fixedly connected to the workbench, and a deviation rectifying assembly is arranged on the workbench; the deviation rectifying assembly can enable the foot pad to do transverse linear motion on the workbench through the combined action of friction force between the deviation rectifying assembly and the foot pad and feed dogs of the sewing machine, during foot pad hemming, an edge measuring probe makes contact with the edge of the foot pad, the edge contour change can cause stress displacement of the edge measuring probe, the swing arm is in linkage with the pressing rod to move, and the foot pad is hemmed. The deviation sensor obtains deviation data, and the control system receives the deviation data collected by the deviation sensor and then judges whether the edge contour of the foot pad is changed or not, so that the action of a servo motor in the deviation rectifying assembly is accurately controlled, and the motion state of a rubber wheel is adjusted. Therefore, real-time tracking and self-adaptive deviation correction of the edge contour of the foot pad are achieved, and the edge covering precision effect of the foot pad is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of sewing equipment, specifically to a foot pad sewing device and sealing method. Background Technology

[0002] Foot pad edging mainly involves sewing edging strips onto the edges of the foot pad using a sewing machine to cover the edges, thereby preventing problems such as wear, peeling, or deformation of the foot pad edges during use, which would affect the lifespan and appearance of the foot pad; foot pad edging is also known as edge sealing or edge banding.

[0003] Currently, in existing technologies, since the feed dog of a sewing machine can only make the foot pad move in a straight line, the industry has designed an automatic sewing machine. The automatic sewing machine is a commonly used automated equipment in the production of foot pads. The automatic sewing machine is equipped with a rubber wheel controlled by a servo motor. The rotation of the rubber wheel is controlled by the servo motor and cooperates with the feed dog of the sewing machine, so that the foot pad can make circular motion, thereby realizing continuous sewing of non-straight edges.

[0004] However, during the sewing process, due to the irregularity of the edge contour of the foot pad, the automatic sewing machine has difficulty in accurately identifying the real-time contour changes of the foot pad edge, causing the sewing path to deviate from the preset trajectory, resulting in uneven edge binding or missing seams; therefore, a foot pad sewing device and sealing method are proposed to address the above problems. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art and solve at least one of the technical problems mentioned in the background art, the present invention proposes a foot pad sewing device and a sealing method.

[0006] The technical solution adopted by the present invention to solve its technical problem is as follows: The foot pad sewing device of the present invention includes a worktable and a sewing machine. The sewing machine is fixedly connected to the worktable, and the worktable is provided with a correction component. The correction component, through the combined action of friction between itself and the foot pad and the feed dog of the sewing machine, enables the foot pad to make a lateral linear movement on the worktable. An edge measuring module is installed on the sewing machine. The edge measuring module is used to detect the contour changes of the foot pad edge in real time and transmit the collected edge data to the control system of the foot pad sewing device.

[0007] Preferably, the edge measuring module includes a support arm, an offset sensor, a swing arm, a pressure rod, and an edge measuring probe. The support arm is fixedly connected to the sewing machine, the swing arm is rotatably connected to the side end of the support arm, and a tension spring is fixedly connected between the swing arm and the support arm. The offset sensor is installed on the top of the support arm, the pressure rod is fixedly connected to the top of the swing arm, and the side of the pressure rod is in contact with the offset sensor. The edge measuring probe is fixedly connected to the bottom end of the swing arm. When the edge of the foot pad contacts the edge measuring probe, the swing arm moves the pressure rod, and the offset sensor collects the offset data of the pressure rod.

[0008] Preferably, the correction assembly includes a frame, a support, a servo motor, and a rubber wheel. The frame is fixed to the top of the workbench, the support is mounted on the frame, the servo motor is fixed to the support, the rubber wheel is rotatably connected to the support, and the output shaft of the servo motor is fixed to the rubber wheel.

[0009] Preferably, the support and the frame are rotatably connected, and a cylinder is rotatably connected to the frame, with the piston rod of the cylinder hinged to the support.

[0010] Preferably, the sewing machine is equipped with a bracket, and a vision sensor is installed on the side of the bracket; the vision sensor is used to collect image information of the edge of the foot pad and transmit the image data to the control system to determine whether the edge of the foot pad has been edge-bound.

[0011] Preferably, the support arm has a mounting hole, the offset sensor is slidably connected in the mounting hole, the surface of the offset sensor has a threaded groove, and multiple locking nuts are connected to the offset sensor through the threaded groove.

[0012] Preferably, the bracket has a horizontal adjustment groove, and a first screw is provided in the horizontal adjustment groove. The first screw is installed on the sewing machine by means of a threaded connection.

[0013] Preferably, the bracket has two angle adjustment slots at one end near the vision sensor, and a second screw is provided in the angle adjustment slot. The second screw is threaded and installed on the vision sensor.

[0014] A method for sealing the edges of a foot pad, applicable to the aforementioned foot pad sewing equipment, comprising the following steps:

[0015] S1: Place the foot pad to be processed on the workbench, with the edge of the foot pad placed under the presser foot of the sewing machine. Start the cylinder, and the piston rod of the cylinder will push the support to swing around the rotating connection point on the machine frame, so that the rubber wheel presses down onto the surface of the foot pad.

[0016] S2: Start the sewing machine. The feed dog of the sewing machine drives the foot pad forward to perform the foot pad hemming.

[0017] S3: The edge measuring probe in the edge measuring module contacts the edge of the foot pad. When the edge contour changes and causes the edge measuring probe to be displaced by force, the swing arm 22 moves in conjunction with the pressure rod 24, and the offset sensor acquires the pressure rod offset data.

[0018] S4: The control system receives offset data collected from the offset sensor, and then determines whether the edge contour of the foot pad has changed. If there is a change, it controls the servo motor to drive the rubber wheel to rotate in both directions. The combined action of the rubber wheel and the feed dog of the sewing machine makes the foot pad move in a horizontal straight line on the worktable, and dynamically corrects the edge of the foot pad.

[0019] S5: The vision sensor synchronously captures images of the foot pad edge and transmits the image data to the control system. The control system analyzes the captured image data and automatically identifies whether the foot pad edge has been wrapped.

[0020] S6: After the foot pad is edged, the control system stops the servo motor and the sewing machine stops sewing. The piston rod of the cylinder retracts, the rubber wheel lifts up and detaches from the foot pad surface.

[0021] The advantages of this invention are:

[0022] 1. This invention utilizes a support arm, a swing arm, a measuring probe, a pressure rod, and an offset sensor. During the hemming of the foot pad, the measuring probe contacts the edge of the foot pad. Changes in the edge contour cause the measuring probe to be displaced by force. The offset sensor acquires the offset data, and a tension spring is used to reset the swing arm. The offset sensor collects the offset data in real time. The control system receives the offset data collected by the offset sensor and then determines whether the edge contour of the foot pad has changed. This allows for precise acquisition of the foot pad edge contour data, facilitating precise control of the servo motor in the correction component and adjusting the movement state of the rubber wheel. This achieves real-time tracking and adaptive correction of the foot pad edge contour, ensuring the accuracy of the foot pad hemming.

[0023] 2. This invention uses a visual sensor to capture images of the foot pad's edge during the sewing process and transmits the image data to the control system. The control system analyzes the captured image data and automatically identifies whether the foot pad's edge has been bound, thereby achieving real-time monitoring and feedback on the binding completion status and avoiding missed stitches or repeated sewing. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the sewing machine structure of the present invention;

[0027] Figure 3 This is a schematic diagram of the support structure of the present invention;

[0028] Figure 4 This is a schematic diagram of the support arm structure of the present invention;

[0029] Figure 5 This is a schematic diagram of the swing arm structure of the present invention;

[0030] Figure 6 This is a schematic diagram of the support structure of the present invention;

[0031] Figure 7 A flowchart illustrating the method for sealing the edges of foot pads.

[0032] In the diagram: 11. Workbench; 12. Sewing machine; 21. Support arm; 22. Swing arm; 23. Edge probe; 24. Pressure bar; 25. Offset sensor; 31. Frame; 32. Support; 33. Servo motor; 34. Rubber wheel; 4. Cylinder; 51. Bracket; 52. Vision sensor; 61. Mounting hole; 62. Threaded groove; 63. Locking nut; 71. Horizontal adjustment groove; 72. First screw; 81. Angle adjustment groove; 82. Second screw. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Specific implementation examples are given below.

[0035] Please see Figure 1-6As shown, a foot pad sewing device includes a worktable 11 and a sewing machine 12. The sewing machine 12 is fixedly connected to the worktable 11, and the worktable 11 is equipped with a deviation correction component. The deviation correction component, through the combined action of friction between itself and the foot pad and the feed dog of the sewing machine 12, enables the foot pad to make lateral linear movement on the worktable 11. An edge measuring module is installed on the sewing machine 12. The edge measuring module is used to detect the contour changes of the foot pad edge in real time and transmit the collected edge data to the control system of the foot pad sewing device. The edge measuring module includes a support arm 21, an offset sensor 25, a swing arm 22, and a pressure rod. The foot pad 24 and the edge probe 23 are connected together. The support arm 21 is fixedly connected to the sewing machine 12. The swing arm 22 is rotatably connected to the side end of the support arm 21. A tension spring is fixedly connected between the swing arm 22 and the support arm 21. The offset sensor 25 is installed on the top of the support arm 21. The pressure rod 24 is fixedly connected to the top of the swing arm 22, and the side of the pressure rod 24 is in contact with the offset sensor 25. The edge probe 23 is fixedly connected to the bottom end of the swing arm 22. When the edge of the foot pad contacts the edge probe 23, the pressure rod 24 is moved by the swing of the swing arm 22. At the same time, the offset sensor 25 collects the offset data of the pressure rod 24.

[0036] In use, the foot pad to be processed is placed on the workbench 11, with the edge of the foot pad under the presser foot of the sewing machine 12. The sewing machine 12 is started, and the feed dog of the sewing machine 12 moves the foot pad forward to perform the edging. The edge probe 23 contacts the edge of the foot pad, and the change in the edge contour will cause the edge probe 23 to be displaced by force. The swing arm 22 moves in conjunction with the pressure rod 24. The offset sensor 25 obtains offset data by measuring the change in distance from the pressure rod 24. The tension spring is used to reset the swing arm 22. The offset sensor 25 collects offset data in real time. The control system receives the offset data collected by the offset sensor 25 and then determines whether the edge contour of the foot pad has changed. This allows for accurate collection of the edge contour data of the foot pad, which facilitates precise control of the servo motor 33 in the correction component and adjusts the movement state of the rubber wheel 34. This enables real-time tracking and adaptive correction of the edge contour of the foot pad, ensuring the accuracy of the edging effect.

[0037] Furthermore, such as Figure 1-6 As shown, the correction assembly includes a frame 31, a support 32, a servo motor 33, and a rubber wheel 34. The frame 31 is fixed to the top of the workbench 11, the support 32 is mounted on the frame 31, the servo motor 33 is fixed to the support 32, and the rubber wheel 34 is rotatably connected to the support 32. The output shaft of the servo motor 33 is fixedly connected to the rubber wheel 34. The support 32 and the frame 31 are rotatably connected. A cylinder 4 is rotatably connected to the frame 31, and the piston rod of the cylinder 4 is hinged to the support 32.

[0038] During use, the piston rod of cylinder 4 pushes the support 32 to swing around the rotating connection point on the frame 31, causing the rubber wheel 34 to press down onto the surface of the foot pad. When it is necessary to correct the posture of the foot pad, the control system controls the servo motor 33 to drive the rubber wheel 34 to rotate forward and backward. The combined action of the rubber wheel 34 and the feed dog of the sewing machine 12 causes the foot pad to make a horizontal linear movement on the worktable 11, adjusting the posture of the foot pad and dynamically correcting the edge of the foot pad, so that the relative position of the edge of the foot pad and the sewing machine 12 remains constant. Cylinder 4 is used to control the pressing force and lifting of the rubber wheel 34 on the surface of the foot pad, and is used for adaptive adjustment when changing foot pads of different thicknesses or materials.

[0039] Furthermore, such as Figure 1-6 As shown, a bracket 51 is mounted on the sewing machine 12, and a vision sensor 52 is mounted on the side of the bracket 51. The vision sensor 52 is used to collect image information of the edge of the foot pad and transmit the image data to the control system to determine whether the edge of the foot pad has been edge-bound. A mounting hole 61 is provided on the support arm 21, and the offset sensor 25 is slidably connected in the mounting hole 61. A threaded groove 62 is provided on the surface of the offset sensor 25, and multiple locking nuts 63 are connected to the offset sensor 25 through the threaded groove 62. A horizontal adjustment groove 71 is provided on the bracket 51, and a first screw 72 is provided in the horizontal adjustment groove 71. The first screw 72 is threadedly connected to the sewing machine 12. Two angle adjustment grooves 81 are provided on the end of the bracket 51 near the vision sensor 52, and a second screw 82 is provided in the angle adjustment groove 81. The second screw 82 is threadedly connected to the vision sensor 52.

[0040] In use, the offset sensor 25 is slidably connected in the mounting hole 61 of the support arm 21, and then locked and fixed on the support arm 21 by two locking nuts 63, thereby realizing the installation of the offset sensor 25 and the support arm 21. The threaded groove 62 and the locking nut 63 cooperate to allow the offset sensor 25 to move left and right, which makes it easy to adjust the initial standard displacement value of the detection according to the thickness or material of the foot pad, improve the detection accuracy and adaptability, and ensure that the offset of the foot pad edge can be accurately identified under different working conditions.

[0041] The bracket 51 is provided with a horizontal adjustment groove 71 and an angle adjustment groove 81. By sliding the first screw 72 in the horizontal adjustment groove 71, the position of the vision sensor 52 in the horizontal direction can be adjusted. The second screw 82 cooperates with the angle adjustment groove 81 to adjust the pitch angle, thereby adjusting the shooting position of the vision sensor 52 to ensure that the vision sensor 52 can accurately capture the edge contour of the foot pad.

[0042] Please see Figure 7A method for sealing the edges of a foot pad, applicable to the aforementioned foot pad sewing equipment, comprising the following steps:

[0043] S1: Place the foot pad to be processed on the workbench 11, with the edge of the foot pad placed under the presser foot of the sewing machine 12. Start the cylinder 4. The piston rod of the cylinder 4 pushes the support 32 to swing around the rotating connection point on the frame 31, so that the rubber wheel 34 presses down onto the surface of the foot pad.

[0044] S2: Start sewing machine 12. The feed dog of sewing machine 12 drives the foot pad to move forward to perform foot pad edge binding.

[0045] S3: The edge measuring probe 23 in the edge measuring module contacts the edge of the foot pad. When the edge contour changes and causes the edge measuring probe 23 to be displaced by force, the swing arm 22 moves in conjunction with the pressure rod 24, and the offset sensor 25 acquires the offset data of the pressure rod 24.

[0046] S4: The control system receives offset data collected from offset sensor 25, and then determines whether the edge contour of the foot pad has changed. If there is a change, the control system controls servo motor 33 to drive rubber wheel 34 to rotate in both directions. The combined action of rubber wheel 34 and feed dog of sewing machine 12 makes the foot pad move in a horizontal straight line on worktable 11 to dynamically correct the edge of the foot pad.

[0047] S5: The vision sensor 52 synchronously captures images of the edge of the foot pad and transmits the image data to the control system. The control system analyzes the captured image data and automatically identifies whether the edge of the foot pad has been wrapped.

[0048] S6: After the foot pad is finished, the control system controls the servo motor 33 to stop working, and at the same time the sewing machine 12 stops sewing, the piston rod of the cylinder 4 retracts, and the rubber wheel 34 is lifted and removed from the surface of the foot pad.

[0049] Working principle: During use, the foot pad to be processed is placed on the workbench 11, with the edge of the foot pad under the presser foot of the sewing machine 12. The sewing machine 12 is started, and the feed dog of the sewing machine 12 drives the foot pad forward to perform foot pad edge binding. The edge probe 23 contacts the edge of the foot pad, and the change in the edge contour will cause the edge probe 23 to be displaced by force. The swing arm 22 moves in conjunction with the pressure rod 24. The offset sensor 25 obtains offset data by measuring the change in distance from the pressure rod 24. The tension spring is used to reset the swing arm 22. The offset sensor 25 collects offset data in real time. The control system receives the offset data collected by the offset sensor 25 and then judges whether the edge contour of the foot pad has changed. This allows for accurate collection of the edge contour data of the foot pad, which facilitates precise control of the servo motor 33 in the correction component and adjusts the movement state of the rubber wheel 34. This enables real-time tracking and adaptive correction of the edge contour of the foot pad, ensuring the accuracy of the foot pad edge binding.

[0050] During use, the piston rod of cylinder 4 pushes the support 32 to swing around the rotating connection point on the frame 31, causing the rubber wheel 34 to press down onto the surface of the foot pad. When it is necessary to correct the posture of the foot pad, the control system controls the servo motor 33 to drive the rubber wheel 34 to rotate forward and backward. The combined action of the rubber wheel 34 and the feed dog of the sewing machine 12 causes the foot pad to make a horizontal linear movement on the worktable 11, adjusting the posture of the foot pad and dynamically correcting the edge of the foot pad, so that the relative position of the edge of the foot pad and the sewing machine 12 remains constant. Cylinder 4 is used to control the pressing force and lifting of the rubber wheel 34 on the surface of the foot pad, and is used for adaptive adjustment when changing foot pads of different thicknesses or materials.

[0051] In use, the offset sensor 25 is slidably connected in the mounting hole 61 of the support arm 21, and then locked and fixed on the support arm 21 by two locking nuts 63, thereby realizing the installation of the offset sensor 25 and the support arm 21. The threaded groove 62 and the locking nut 63 cooperate to allow the offset sensor 25 to move left and right, which makes it easy to adjust the initial standard displacement value of the detection according to the thickness or material of the foot pad, improve the detection accuracy and adaptability, and ensure that the offset of the foot pad edge can be accurately identified under different working conditions.

[0052] The bracket 51 is provided with a horizontal adjustment groove 71 and an angle adjustment groove 81. By sliding the first screw 72 in the horizontal adjustment groove 71, the position of the vision sensor 52 in the horizontal direction can be adjusted. The second screw 82 cooperates with the angle adjustment groove 81 to adjust the pitch angle, thereby adjusting the shooting position of the vision sensor 52 to ensure that the vision sensor 52 can accurately capture the edge contour of the foot pad.

[0053] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0054] The foregoing has shown and described 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 embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A foot pad sewing device, comprising a workbench (11) and a sewing machine (12), wherein the sewing machine (12) is fixedly connected to the workbench (11), and the workbench (11) is provided with a correction component; the correction component, through the combined action of friction between itself and the foot pad and the feed dog of the sewing machine (12), enables the foot pad to make a lateral linear movement on the workbench (11); characterized in that: The sewing machine (12) is equipped with an edge measuring module, which is used to detect the contour changes of the foot pad edge in real time and transmit the collected edge data to the control system of the foot pad sewing equipment.

2. The foot pad sewing device according to claim 1, characterized in that: The edge measuring module includes a support arm (21), an offset sensor (25), a swing arm (22), a pressure rod (24), and an edge measuring probe (23). The support arm (21) is fixed to the sewing machine (12). The swing arm (22) is rotatably connected to the side of the support arm (21). A tension spring is fixedly connected between the swing arm (22) and the support arm (21). The offset sensor (25) is installed on the top of the support arm (21). The pressure rod (24) is fixed to the top of the swing arm (22), and the side of the pressure rod (24) is in contact with the offset sensor (25). The edge measuring probe (23) is fixed to the bottom of the swing arm (22). When the edge of the foot pad contacts the edge measuring probe (23), the probe is forced to rotate the swing arm (22), thereby causing the pressure rod (24) to move through the swing of the swing arm (22). At the same time, the offset sensor (25) collects the offset data of the pressure rod (24).

3. The foot pad sewing device according to claim 2, characterized in that: The correction assembly includes a frame (31), a support (32), a servo motor (33), and a rubber wheel (34). The frame (31) is fixed to the top of the workbench (11). The support (32) is mounted on the frame (31). The servo motor (33) is fixed to the support (32). The rubber wheel (34) is rotatably connected to the support (32). The output shaft of the servo motor (33) and the rubber wheel (34) are fixedly connected.

4. The foot pad sewing device according to claim 3, characterized in that: The support (32) and the frame (31) are rotatably connected. A cylinder (4) is rotatably connected to the frame (31). The piston rod of the cylinder (4) is hinged to the support (32).

5. The foot pad sewing device according to claim 4, characterized in that: The sewing machine (12) is equipped with a bracket (51), and a vision sensor (52) is installed on the side of the bracket (51). The vision sensor (52) is used to collect image information of the edge of the foot pad and transmit the image data to the control system to determine whether the edge of the foot pad has been edged.

6. The foot pad sewing device according to claim 2, characterized in that: The support arm (21) has a mounting hole (61), the offset sensor (25) is slidably connected in the mounting hole (61), the offset sensor (25) has a threaded groove (62) on its surface, and multiple locking nuts (63) are connected to the offset sensor (25) through the threaded groove (62).

7. The foot pad sewing device according to claim 5, characterized in that: The bracket (51) is provided with a horizontal adjustment groove (71), and a first screw (72) is provided in the horizontal adjustment groove (71). The first screw (72) is installed on the sewing machine (12) by threaded connection.

8. The foot pad sewing device according to claim 7, characterized in that: The bracket (51) has two angle adjustment slots (81) at one end near the vision sensor (52). The angle adjustment slots (81) are provided with a second screw (82), which is threaded onto the vision sensor (52).

9. A method for sealing the edges of a foot pad, characterized in that: This edge-sealing method is applicable to the foot pad sewing device of claim 5, and the edge-sealing method includes the following steps: S1: Place the foot pad to be processed on the workbench (11), with the edge of the foot pad placed under the presser foot of the sewing machine (12). Start the cylinder (4). The piston rod of the cylinder (4) pushes the support (32) to swing around the rotating connection point on the frame (31), so that the rubber wheel (34) presses down onto the surface of the foot pad. S2: Start the sewing machine (12). The feed dog of the sewing machine (12) drives the foot pad to move forward to perform foot pad edge binding. S3: The edge probe (23) in the edge measuring module contacts the edge of the foot pad. When the edge contour changes and the edge probe (23) is displaced by force, the swing arm (22) moves in conjunction with the pressure rod (24), and the offset sensor (25) acquires the offset data of the pressure rod (24). S4: The control system receives the offset data collected from the offset sensor (25), and then determines whether the edge contour of the foot pad has changed. If there is a change, the control system controls the servo motor (33) to drive the rubber wheel (34) to rotate in both directions. The combined action of the rubber wheel (34) and the feed dog of the sewing machine (12) makes the foot pad move in a horizontal straight line on the worktable (11) to dynamically correct the edge of the foot pad. S5: The visual sensor (52) synchronously captures the image of the edge of the foot pad and transmits the image data to the control system. The control system analyzes the captured image data and automatically identifies whether the edge of the foot pad has been wrapped. S6: After the foot pad is finished, the control system controls the servo motor (33) to stop working, and at the same time the sewing machine (12) stops sewing, the piston rod of the cylinder (4) retracts, and the rubber wheel (34) lifts up and detaches from the surface of the foot pad.

Images