High-speed rail foundation wet expansive force measuring device

Abstract

The invention discloses a high-speed rail foundation wet expansive force measuring device, and relates to the technical field of testing, the high-speed rail foundation wet expansive force measuring device comprises a testing barrel, a hydraulic bag is fixedly arranged in the testing barrel, the hydraulic bag is communicated with a hydraulic pipe, a hinge rod is hinged to one side of the testing barrel, a matching plate is hinged to the hinge rod, a testing sample is placed in the testing barrel, and the testing sample clings to the hydraulic bag and the matching plate. A bottom plugging plate is fixedly installed on the lower side of the matching plate, the testing barrel presses the bottom plugging plate downwards to make contact with the bottom layer plate, the matching plate is tightly attached to a testing sample, the hydraulic pipe and the hydraulic bag are filled with liquid, and a pressure meter is installed at the end of the hydraulic pipe. Water is added into the test barrel to enable the test sample to expand to extrude the hydraulic bag, liquid in the hydraulic bag extrudes the press machine through the hydraulic pipe to test the extrusion strength, and the matching plate is arranged to adjust the space in the test barrel to adapt to different test samples.

Description

Technical Field

[0001] The invention relates to the field of testing technology, and in particular to a device for measuring the swelling force of a high-speed railway foundation. Background Art

[0002] In the construction of high-speed railways, the stability of the foundation directly affects the safety and operating life of the line, and swelling force is one of the important factors that cause foundation deformation. High-speed railway foundations are usually composed of expansive soils such as mudstone and clay. These soils will expand significantly after absorbing water, generating swelling force, which in turn causes problems such as uneven foundation uplift and track deformation. Traditional foundation monitoring mainly focuses on settlement and bearing capacity, but there are still deficiencies in the systematic measurement of swelling force, especially under complex geological conditions, and there is a lack of high-precision, real-time monitoring methods for swelling force.

[0003] From the perspective of swelling force testing technology, existing methods mainly include laboratory tests and field monitoring. However, laboratory tests are difficult to fully simulate the humidity changes and load conditions of the actual foundation, and field monitoring devices often have problems such as complex installation, insufficient long-term stability, and large data discreteness. In addition, existing swelling force measurement devices are mostly designed for ordinary soils and have poor adaptability to the special working conditions of high-speed rail foundations, resulting in measurement accuracy and reliability that are difficult to meet the needs of high-speed rail projects. In existing laboratory tests, only samples of fixed sizes can be tested, and direct contact testing with samples through pressure sensors is not accurate. Summary of the invention

[0004] In view of the above technical problems, the present invention discloses a device for measuring the swelling force of a high-speed railway foundation, including a test barrel, a hydraulic bag fixedly installed inside the test barrel, a hydraulic pipe connected to the hydraulic bag, a hinged rod hinged on one side of the test barrel, a matching plate hinged on the hinged rod, a test sample placed in the test barrel, the test sample close to the hydraulic bag and the matching plate, a bottom blocking plate fixedly installed on the lower side of the matching plate, the test barrel presses the bottom blocking plate downward to contact the bottom plate, the matching plate and the test sample close, the hydraulic pipe and the hydraulic bag are filled with liquid, and a pressure gauge is installed at the end of the hydraulic pipe. Through the above technical scheme, water is added to the test barrel to make the test sample expand and squeeze the hydraulic bag, the liquid in the hydraulic bag is tested for extrusion strength through a hydraulic pipe extrusion press, and the matching plate is arranged to adjust the space in the test barrel to adapt to different test samples.

[0005] Furthermore, a track plate is fixed on the bottom plate, suppression fixing ears are fixed on both sides of the test barrel, a suppression shaft is slidably mounted on the suppression fixing ears, a suppression plate is fixed on the bottom of the suppression shaft, the suppression plate is in contact with the track plate, and a suppression spring is fixed between the suppression fixing ears and the suppression shaft.

[0006] Furthermore, two vertical support plates are fixedly mounted on the track plate, and transverse support plates are respectively fixedly mounted on the two vertical support plates, wherein a first pulley is rotatably mounted at both ends of one of the transverse support plates, and a first belt is mounted on the first pulley, and second pulleys are rotatably mounted at both ends of the other transverse support plate, and a second belt is mounted on the second pulley, a first side plate is fixedly mounted on the first belt, and a second side plate is fixedly mounted on the second belt, a clamping assembly is hinged between the second side plate and the first side plate, and the clamping assembly clamps the test sample, and the test sample is vertically downward in a natural state.

[0007] Furthermore, the track plate is provided with a track, and a pressure plate is slidably provided on the track. In a natural state, the roller does not contact the bottom plate, and the height of the matching plate is lower than the test barrel. The test sample follows the movement of the second belt and the first belt to be inserted into the test barrel, and the roller is pressed on the bottom plate, and the bottom blocking plate is in contact with the bottom of the test barrel. Through the above technical solution, the test sample is automatically inserted into the test barrel and squeezes the test barrel downward, and finally the bottom blocking plate fits with the bottom of the test barrel, the matching plate fits with the test sample, and drives the roller to move on the bottom plate. The test sample can be automatically combined with the test barrel by the driving of the second belt and the first belt, and multiple test samples can be tested at the same time.

[0008] Furthermore, a limit block is fixedly mounted on the matching plate, and the upper end of the hinged rod contacts the limit block in a natural state.

[0009] Furthermore, the clamping assembly includes a fixed frame, and rotating shafts are fixedly mounted on both ends of the fixed frame. The rotating shafts are hinged to the second side plate and the first side plate, and the test sample is fixed in the third motor.

[0010] Furthermore, a clamping plate is slidably mounted in the fixing frame, a fixing bolt is rotatably mounted on the clamping plate, the fixing bolt cooperates with the fixing frame, and the rotating fixing bolt drives the clamping plate to squeeze the test sample.

[0011] Furthermore, a fixing plate is fixedly mounted on the upper end of the fixing frame, and an extrusion plate is fixedly mounted on the lower side of the fixing plate, the extrusion plate contacts the upper part of the test sample, and a water pipe is fixedly mounted inside the fixing plate and the extrusion plate, and the water pipe runs through the extrusion plate. Through the above technical solution, the clamping plate in the fixing frame can clamp the test sample, and water can be injected into the test sample through the water pipe to simulate the swelling of the test sample.

[0012] Furthermore, two third pulleys are rotatably mounted at both ends of the transverse support plate, the center distance of the two third pulleys is the same as the center distance of the two first pulleys, and they are staggered, the third pulley is mounted with a third belt, the third belt is fixedly mounted with a third side plate, a connecting rod is hinged on the third side plate, a fixed block is fixedly mounted on the rotating shaft, the fixed block is fixedly connected to the connecting rod, and the connecting rod always remains in a horizontal state. Through the above technical solution, the staggered third belt and the third belt can keep the connecting rod horizontal, thereby keeping the test sample vertical, and the test sample remains vertical to ensure accurate insertion into the test barrel, and can drive the test barrel to move in a vertical state.

[0013] Furthermore, a short support plate is fixedly mounted on the vertical support plate, a second motor is fixedly mounted on the short support plate for driving the third pulley, a third motor is fixedly mounted on the side of the transverse support plate, an end gear is fixedly mounted on the second pulley, the end gear is meshed with the driving gear, and a first motor is fixedly mounted on the transverse support plate for driving the first pulley.

[0014] The beneficial effects of the present invention compared with the prior art are: (1) Through the above technical solution, water is added to the test barrel to make the test sample expand and squeeze the hydraulic bag. The liquid in the hydraulic bag is tested for extrusion strength through a hydraulic pipe extrusion press. The matching plate can adjust the space in the test barrel to adapt to different test samples.

[0015] (2) Through the above technical solution, the test sample is automatically inserted into the test barrel and squeezed downward. Finally, the bottom sealing plate fits with the bottom of the test barrel, the matching plate fits with the test sample, and drives the roller to move on the bottom plate. The test sample can be automatically combined with the test barrel through the drive of the second belt and the first belt, and multiple test samples can be tested at the same time.

[0016] (3) Through the above technical solution, the clamping plate in the fixed frame can clamp the test sample, and water can be injected into the test sample through the water pipe to simulate the swelling of the test sample.

[0017] (4) Through the above technical solution, the staggered third belt and the third belt can keep the connecting rod horizontal, thereby keeping the test sample vertical. The test sample remains vertical to ensure accurate insertion into the test barrel, and can drive the test barrel to move while maintaining a vertical state. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The overall structure of a high-speed railway foundation expansion force measuring device according to an embodiment of the present invention is shown in FIG. Figure 1 .

[0019] Figure 2 The overall structure of a high-speed railway foundation expansion force measuring device according to an embodiment of the present invention is shown in FIG. Figure 2 .

[0020] Figure 3 This is a schematic diagram of some parts of a high-speed railway foundation expansion force measuring device according to an embodiment of the present invention.

[0021] Figure 4 This is a schematic diagram of a test component of a high-speed railway foundation expansion force measurement device according to an embodiment of the present invention.

[0022] Figure 5 A schematic diagram of a clamping assembly of a high-speed railway foundation expansion force measuring device according to an embodiment of the present invention Figure 1 .

[0023] Figure 6 A schematic diagram of a clamping assembly of a high-speed railway foundation expansion force measuring device according to an embodiment of the present invention Figure 2 .

[0024] Figure numbers: 1-bottom frame; 2-bottom plate; 3-vertical support plate; 4-lateral support plate; 5-first motor; 6-first pulley; 7-second pulley; 8-third pulley; 9-third belt; 10-third side plate; 11-second belt; 12-first belt; 13-connecting rod; 14-second side plate; 15-first side plate; 16-short support plate; 17-second motor; 18-third motor; 19-driving gear; 20-face gear; 21-rotating shaft ; 22-fixed block; 23-fixed plate; 24-extrusion plate; 25-water pipe; 26-fixing bolt; 27-clamping plate; 28-fixing frame; 29-test sample; 30-test barrel; 31-suppression plate; 32-suppression fixing ear; 33-hydraulic pipe; 34-suppression spring; 35-suppression shaft; 36-hydraulic bag; 37-hinge shaft; 38-limiting block; 39-hinge rod; 40-matching plate; 41-bottom blocking plate; 42-roller; 43-track plate. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] like Figure 1-Figure 6A high-speed railway foundation swelling force measuring device shown in the figure includes a bottom plate 2, a bottom frame 1 is fixedly mounted on the bottom plate 2, a track plate 43 is fixedly mounted on the bottom frame 1, three groups of pulley assemblies are mounted on the track plate 43, and in other embodiments, it can also be a sprocket assembly, two groups of which are concentrically arranged side by side, and the other group is staggered, a clamping assembly is installed between the two concentrically arranged pulley assemblies, and a test assembly is installed on the track plate 43, and a test sample 29 is driven by the pulley to insert into the test assembly for testing.

[0027] In this embodiment, a track plate 43 is fixedly mounted on the bottom plate 2, a bottom frame 1 is fixedly mounted between the bottom plate 2 and the track plate 43, two vertical support plates 3 are fixedly mounted on the track plate 43, and transverse support plates 4 are respectively fixedly mounted on the two vertical support plates 3, a first pulley 6 is rotatably mounted at both ends of one of the transverse support plates 4, a first belt 12 is mounted on the first pulley 6, a second belt 11 is rotatably mounted at both ends of the other transverse support plate 4, a second belt 11 is mounted on the second pulley 7, a first side plate 15 is fixedly mounted on the first belt 12, a second side plate 14 is fixedly mounted on the second belt 11, a clamping assembly is hinged between the second side plate 14 and the first side plate 15, the clamping assembly clamps the test sample 29, the test sample 29 is vertically downward in a natural state, the first pulley 6 and the second pulley 7 are coaxially mounted, but driven separately, the first pulley 6 and the second pulley 7 are not connected, and the test sample 29 mounted between the first pulley 6 and the second pulley 7 must move from between the first pulley 6 and the second pulley 7 and cannot be interfered with.

[0028] In this embodiment, two third pulleys 8 are rotatably installed at both ends of the transverse support plate 4. The center distance between the two third pulleys 8 is the same as the center distance between the two first pulleys 6, and they are staggered. A third belt 9 is installed on the third pulley 8, and a third side plate 10 is fixedly installed on the third belt 9. A plurality of third side plates 10 are provided, and the number is the same as the number of second side plates 14 and first side plates 15. A plurality of second side plates 14 and first side plates 15 are also provided, thereby multiple clamping assemblies can be installed. A connecting rod 13 is hinged on the third side plate 10, and a fixed block 22 is fixedly installed on the rotating shaft 21. The fixed block 22 is fixedly connected to the connecting rod 13, and the connecting rod 13 always remains in a horizontal state. The staggered third belt 9 and the third belt 9 can keep the connecting rod 13 horizontal, and then keep the test sample 29 vertical. The test sample 29 remains vertical to ensure accurate insertion into the test barrel 30, and can drive the test barrel 30 to move while maintaining a vertical state. A short support plate 16 is fixedly mounted on the vertical support plate 3, and a second motor 17 is fixedly mounted on the short support plate 16 for driving the third pulley 8. A third motor 18 is fixedly mounted on the side of the transverse support plate 4, and an end gear 20 is fixedly mounted on the second pulley 7, which is meshed with the driving gear 19. A first motor 5 is fixedly mounted on the transverse support plate 4 for driving the first pulley 6.

[0029] Specifically, in the present embodiment, the test assembly includes a test barrel 30, which is a hollow structure with one side open. A hydraulic bag 36 is fixedly installed inside the test barrel 30, and the hydraulic bag 36 is connected to the hydraulic pipe 33. A hinge rod 39 is hinged on one side of the opening of the test barrel 30. Specifically, a hinge shaft 37 is fixedly installed on the test barrel 30, and the hinge rod 39 is hinged on the hinge shaft 37. A matching plate 40 is hinged on the hinge shaft 37. Two hinge shafts 37 and two hinge rods 39 are provided. The upper and lower ends of the matching plate 40 are respectively hinged to the two hinged rods 39 to form a parallelogram connecting rod structure. The test sample 29 is placed in the test barrel 30. The test sample 29 is close to the hydraulic bag 36 and the matching plate 40. A bottom sealing plate 41 is fixed on the lower side of the matching plate 40. The test barrel 30 presses the bottom sealing plate 41 downward to contact the bottom plate 2. The matching plate 40 is close to the test sample 29. The hydraulic pipe 33 and the hydraulic bag 36 are filled with liquid, and a pressure gauge is installed at the end of the hydraulic pipe 33. Add water into the test barrel 30 to expand the test sample 29 and squeeze the hydraulic bag 36. The liquid in the hydraulic bag 36 is squeezed through the hydraulic pipe 33 to test the extrusion strength of the press. The matching plate 40 can adjust the space in the test barrel 30 to adapt to different test samples 29. The test barrel 30 has fixed suppression ears 32 on both sides, and a suppression shaft 35 is slidably mounted on the suppression ears 32. A suppression plate 31 is fixedly mounted on the bottom of the suppression shaft 35. The suppression plate 31 is in contact with the track plate 43, and a suppression spring 34 is fixedly mounted between the suppression ears 32 and the suppression shaft 35.

[0030] In this embodiment, a track is installed on the track plate 43, and a pressing plate 31 is installed on the track for sliding. In the natural state, the roller 42 does not contact the bottom plate 2, and the matching plate 40 is lower than the test barrel 30. The test sample 29 follows the second belt 11 and the first belt 12 to move into the test barrel 30, and presses the roller 42 on the bottom plate 2, and the bottom blocking plate 41 contacts the bottom of the test barrel 30. The test sample 29 is automatically inserted into the test barrel 30 and presses the test barrel 30 downward. Finally, the bottom blocking plate 41 fits the bottom of the test barrel 30, and the matching plate 40 fits the test sample 29 and drives the roller 42 to move on the bottom plate 2. The test sample 29 can be automatically combined with the test barrel 30 by the driving of the second belt 11 and the first belt 12, and multiple test samples 29 are tested at the same time. A limit block 38 is fixed on the matching plate 40, and the upper end of the hinged rod 39 contacts the limit block 38 in the natural state.

[0031] The clamping assembly includes a fixed frame 28, which is a square frame structure. The two ends of the fixed frame 28 are fixedly provided with a rotating shaft 21, which is hinged with the second side plate 14 and the first side plate 15. The test sample 29 is fixed in the third motor 18. A clamping plate 27 is slidably provided in the fixed frame 28, and a fixing bolt 26 is rotatably provided on the clamping plate 27. The fixing bolt 26 cooperates with the fixed frame 28, and the rotating fixing bolt 26 drives the clamping plate 27 to squeeze the test sample 29. A fixed plate 23 is fixedly provided on the upper end of the fixed frame 28, and an extrusion plate 24 is fixedly provided on the lower side of the fixed plate 23. The extrusion plate 24 contacts the upper part of the test sample 29. A water pipe 25 is fixedly provided in the fixed plate 23 and the extrusion plate 24, and the water pipe 25 passes through the extrusion plate 24. Water is injected into the fixing frame 28 through the squeezing plate 24 to allow the test sample 29 to absorb and expand. The clamping plate 27 in the fixing frame 28 can clamp the test sample 29 and water can be injected into the test sample 29 through the water pipe 25 to simulate the swelling of the test sample 29.

[0032] Working principle: prepare multiple test components and place them on one side of the track plate 43. In the natural state, the pressure plate 31 contacts the track plate 43 and is supported by the pressure spring 34. The roller 42 leaves the bottom plate 2 and the bottom blocking plate 41 does not contact the test barrel 30. At the same time, the top height of the limit block 38 is lower than the top of the test barrel 30, and the matching plate 40 is also in a naturally drooping state. Then open the fixing plate 23, place the test sample 29 in the fixing frame 28, tighten the fixing bolts 26, and let the clamping plate 27 press the test sample 29. Then fix the fixing plate 23 to the fixing frame 28 with bolts, start all motors, and drive the clamping assembly to move. At this time, the clamping assembly follows the second side plate 14 and the first side plate 15 to move, and the test sample 29 is always kept vertically downward through the connection of the staggered third side plate 10 and the connecting rod 13. Manually place the test component on the track plate 43, and then the test sample 29 gradually lowers its height and just enters the test barrel 30 from the upper side of the matching plate 40. In the test barrel 30, due to the low height of the matching plate 40, the test sample 29 will contact the hydraulic bag 36 in the test barrel 30, driving the test barrel 30 to move until the lower end of the fixed frame 28 contacts the upper end of the test barrel 30, and starts to press the test barrel 30 downward, and finally the roller 42 contacts and rolls with the bottom plate 2, the bottom blocking plate 41 fits with the bottom of the test barrel 30, and with the cooperation of the hinged rod 39, the matching plate 40 also presses the test sample 29, and the test assembly is manually placed to cooperate with the test samples 29 of multiple clamping assemblies, and finally stops, and water is passed into the water pipe 25. After control, the test sample 29 can begin to expand, and the liquid in the hydraulic bag 36 is squeezed during the expansion process. The liquid in the hydraulic bag 36 is squeezed through the hydraulic pipe 33 to squeeze the pressure gauge for measurement. In this process, the test sample 29 is installed in other clamping assemblies. After the test is completed, the start motor drives the test assembly to leave the track plate 43 through the pulley assembly, and then the new test sample 29 is tested with the test assembly.

[0033] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A high-speed railway foundation swelling force measuring device, characterized in that: The invention comprises a test barrel (30), wherein a hydraulic bag (36) is fixedly installed inside the test barrel (30), and the hydraulic bag (36) is connected to a hydraulic pipe (33). A hinge rod (39) is hinged on one side of the test barrel (30), and a matching plate (40) is hinged on the hinge rod (39). A test sample (29) is placed in the test barrel (30), and the test sample (29) is closely attached to the hydraulic bag (36) and the matching plate (40). A bottom blocking plate (41) is fixedly installed on the lower side of the matching plate (40). The test barrel (30) presses the bottom blocking plate (41) downward to contact the bottom plate (2), and the matching plate (40) is closely attached to the test sample (29). The hydraulic pipe (33) and the hydraulic bag (36) are filled with liquid, and a pressure gauge is installed at the end of the hydraulic pipe (33).

2. A high-speed railway foundation swelling force measuring device according to claim 1, characterized in that: A track plate (43) is fixedly mounted on the bottom plate (2), and suppression fixing ears (32) are fixedly mounted on both sides of the test barrel (30). A suppression shaft (35) is slidably mounted on the suppression fixing ears (32), and a suppression plate (31) is fixedly mounted on the bottom of the suppression shaft (35). The suppression plate (31) is in contact with the track plate (43), and a suppression spring (34) is fixedly mounted between the suppression fixing ears (32) and the suppression shaft (35).

3. A high-speed railway foundation swelling force measuring device according to claim 2, characterized in that: Two vertical support plates (3) are fixedly mounted on the track plate (43), and transverse support plates (4) are respectively fixedly mounted on the two vertical support plates (3), and first pulleys (6) are rotatably mounted at both ends of one of the transverse support plates (4), and a first belt (12) is mounted on the first pulley (6), and second pulleys (7) are rotatably mounted at both ends of the other transverse support plate (4), and a second belt (11) is mounted on the second pulley (7), and a first side plate (15) is fixedly mounted on the first belt (12), and a second side plate (14) is fixedly mounted on the second belt (11), and a clamping assembly is hinged between the second side plate (14) and the first side plate (15), and the clamping assembly clamps the test sample (29), and the test sample (29) is vertically downward in a natural state.

4. A high-speed railway foundation swelling force measuring device according to claim 3, characterized in that: The track plate (43) is provided with a track, and a pressing plate (31) is slidably provided on the track. In a natural state, the roller (42) does not contact the bottom plate (2), and the matching plate (40) is lower than the test barrel (30). The test sample (29) moves along with the second belt (11) and the first belt (12) to be inserted into the test barrel (30), and the roller (42) is pressed against the bottom plate (2), and the bottom blocking plate (41) is in contact with the bottom of the test barrel (30).

5. A high-speed railway foundation swelling force measuring device according to claim 4, characterized in that: A limit block (38) is fixedly mounted on the matching plate (40), and the upper end of the hinged rod (39) contacts the limit block (38) in a natural state.

6. A high-speed railway foundation expansion force measuring device according to claim 5, characterized in that: The clamping assembly comprises a fixed frame (28), with rotating shafts (21) fixedly mounted at both ends of the fixed frame (28), the rotating shafts (21) being hingedly connected to the second side plate (14) and the first side plate (15), and the test sample (29) being fixed in the third motor (18).

7. A high-speed railway foundation swelling force measuring device according to claim 6, characterized in that: A clamping plate (27) is slidably mounted in the fixing frame (28), and a fixing bolt (26) is rotatably mounted on the clamping plate (27). The fixing bolt (26) cooperates with the fixing frame (28), and the rotating fixing bolt (26) drives the clamping plate (27) to squeeze the test sample (29).

8. A high-speed railway foundation swelling force measuring device according to claim 7, characterized in that: A fixing plate (23) is fixedly mounted on the upper end of the fixing frame (28), an extrusion plate (24) is fixedly mounted on the lower side of the fixing plate (23), the extrusion plate (24) contacts the upper part of the test sample (29), and a water pipe (25) is fixedly mounted inside the fixing plate (23) and the extrusion plate (24), the water pipe (25) passes through the extrusion plate (24).

9. A high-speed railway foundation swelling force measuring device according to claim 8, characterized in that: Two third pulleys (8) are rotatably mounted at both ends of the transverse support plate (4); the center distance between the two third pulleys (8) is the same as the center distance between the two first pulleys (6) and the third pulleys (8) are staggered; a third belt (9) is mounted on the third pulley (8); a third side plate (10) is fixedly mounted on the third belt (9); a connecting rod (13) is hingedly mounted on the third side plate (10); a fixed block (22) is fixedly mounted on the rotating shaft (21); the fixed block (22) is fixedly connected to the connecting rod (13); and the connecting rod (13) always maintains a horizontal state.

10. A high-speed railway foundation swelling force measuring device according to claim 9, characterized in that: A short support plate (16) is fixedly mounted on the vertical support plate (3), a second motor (17) is fixedly mounted on the short support plate (16) for driving a third pulley (8), a third motor (18) is fixedly mounted on the side of the transverse support plate (4), an end gear (20) is fixedly mounted on the second pulley (7), the end gear (20) is meshed with a driving gear (19), and a first motor (5) is fixedly mounted on the transverse support plate (4) for driving the first pulley (6).

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