Adjustable body position supporting device for prone position operation

By designing the head, torso and leg support components of the adjustable body support device and adopting an electric adjustment mechanism, the problem that traditional prone surgical devices cannot be adjusted is solved, personalized support for patients is achieved, and the risk of pressure sores and nerve damage is reduced.

CN120585582AInactive Publication Date: 2025-09-05南昌大学第一附属医院
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Patent Information

Application Number
CN202511009724.7
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-07-22
Publication Date
2025-09-05
Estimated Expiration
Not applicable · inactive patent

AI Technical Summary

Technical Problem

Traditional prone surgical support devices cannot be flexibly adjusted according to the body shape, surgical site and surgical requirements of different patients, which can easily lead to local pressure concentration and increase the risk of pressure sores or nerve damage.

Method used

An adjustable body support device including head, trunk and leg support components was designed. An electric telescopic rod, an adjustment screw and a motor-driven adjustment mechanism were used to achieve flexible adjustment of the cheek pad spacing, the mandibular pad position, the trunk support component angle and the leg support position.

Benefits of technology

It achieves flexible adjustment based on the patient's body shape and surgical needs, avoids local pressure concentration during prone surgery, and reduces the risk of pressure sores and nerve damage.

✦ Generated by Eureka AI based on patent content.

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Abstract

The invention discloses an adjustable body position supporting device for prone position surgery, which comprises a base, and a horizontal supporting table is fixedly arranged at the upper part of the base; a head supporting assembly, a trunk supporting assembly and a leg supporting assembly are sequentially arranged on the upper portion of the supporting table. The head supporting assembly comprises two cheek supporting pads and a lower jaw supporting pad, the two cheek supporting pads are symmetrically arranged on the supporting table, the lower jaw supporting pad is arranged between the two cheek supporting pads in a sliding mode, and a face width adjusting mechanism used for adjusting the distance between the two cheek supporting pads is arranged between the end of the supporting table and the two cheek supporting pads. A lower jaw adjusting mechanism used for driving the lower jaw supporting cushion to move is arranged at the bottom of the supporting table. The device can be flexibly adjusted according to the body type, the operation site and the operation type requirement of a patient, the situation that local pressure of the body of the patient is concentrated in the prone position operation process is avoided, and the risk of pressure sores or nerve injuries is reduced.
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Description

Technical Field

[0001] The present invention relates to the field of surgical facilities, and in particular to an adjustable body position support device for prone position surgery. Background Art

[0002] In clinical surgical operations, the prone position is a commonly used position for spinal, posterior cranial fossa, urology and other surgeries. During prone surgery, the patient lies face down on the operating table, which is equipped with a position pad to support the patient's head, torso and lower limbs. However, traditional prone support devices have many limitations. For example, most of the position pads used to support patients adopt a fixed structure and cannot be flexibly adjusted according to the body shape, surgical site and surgical requirements of different patients. This can easily lead to local pressure concentration and increase the risk of pressure sores or nerve damage. Therefore, an adjustable position support device for prone surgery was developed. Summary of the Invention

[0003] The purpose of the present invention is to provide an adjustable body support device for prone surgery to solve the technical problems mentioned in the above background technology.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The present invention discloses an adjustable body position support device for prone position surgery, which comprises a base. A horizontal support platform is fixedly provided on the upper part of the base.

[0006] The upper part of the support platform is provided with a head support component, a trunk support component and a leg support component in sequence.

[0007] The head support assembly includes two cheek pads symmetrically arranged on the support platform and a chin pad slidably arranged between the two cheek pads. A face width adjustment mechanism for adjusting the distance between the two cheek pads is provided between the end of the support platform and the two cheek pads. A chin adjustment mechanism for driving the chin pad to move is provided at the bottom of the support platform.

[0008] The trunk support assembly and the leg support assembly are both slidably arranged on the upper part of the support platform, and the upper part of the support platform is provided with a position adjustment mechanism for driving the trunk support assembly and the leg support assembly to move.

[0009] Furthermore, the face width adjustment mechanism includes a first vertical plate fixedly arranged in the middle of the end portion of the support platform and a first electric telescopic rod fixedly arranged horizontally on the outside of the first vertical plate, the telescopic end of the first electric telescopic rod is fixedly provided with a push-pull block, and the push-pull block is hingedly connected to one end of two symmetrically arranged connecting rods; the ends of the two cheek pads away from the mandibular pad are respectively fixedly connected to the L-shaped slide, one end of the two slides is respectively fixedly connected to the corresponding cheek pads, the other ends of the two slides are slidably matched with the horizontal slide groove opened on the support platform, and the middle parts of the two slides are respectively hingedly connected to the other ends of the two connecting rods.

[0010] Furthermore, the mandibular adjustment mechanism includes a second vertical plate fixedly arranged on the bottom of the support platform, a second electric telescopic rod is fixedly arranged on the second vertical plate, the telescopic end of the second electric telescopic rod is fixedly connected to the connecting plate, the upper end of the connecting plate is fixedly connected to the bottom of the slider, the middle part of the slider is slidably matched with the longitudinal slide groove opened on the support platform, and the upper part of the slider is fixedly connected to the middle of the bottom of the mandibular support pad.

[0011] Furthermore, the torso support assembly includes a movable frame slidably arranged on the support platform, the cross-section of the movable frame is an inverted U-shape and its two inner side walls are respectively in contact with the two sides of the support platform, a slide plate is fixedly arranged inside the movable frame and is flat against the upper surface of the support platform, and first limit blocks are respectively fixedly arranged on the two side panels of the movable frame and are flat against the lower surface of the support platform; a torso support pad is provided on the upper part of the movable frame.

[0012] Material toggling mechanism, its both sides respectively have a cylinder pressure, and the cylinder pressure bar connects swing arm, and the swing arm end face has hook portion, and a bar passes position between the end of two swing arms and the hook portion.

[0013] Furthermore, the trunk support pad is made of a bendable and deformable sponge pad or a silicone pad.

[0014] Furthermore, a horizontal driving shaft is provided on one side of the first motor for rotation, one end of the driving shaft is connected to the output end of the first motor, and the other end is provided with a driving bevel gear, and the upper part of the adjusting screw is provided with a driven bevel gear adapted to the driving bevel gear.

[0015] Furthermore, the leg support assembly includes a foot support pad slidably arranged on the upper part of the support platform, and two side limit plates that are flat on both sides of the support platform are fixedly provided on both sides of the bottom end of the foot support pad, and the two side limit plates are respectively fixed with second limit blocks that are flat on the lower surface of the support platform; a mounting groove is provided in the middle of the foot drag pad, and two sliding seats are symmetrically slidably arranged in the mounting groove, and one end of the two sliding seats close to the torso support pad respectively extends to the outside of the foot support pad and is fixed with a leg support pad

[0016] Furthermore, a bidirectional screw is provided for horizontal rotation in the middle of the inner part of the mounting groove, and a second motor for driving the bidirectional screw to rotate is provided on the outer side of the foot support pad; the external threads at both ends of the bidirectional screw rotate in opposite directions, and the two slides are respectively provided with threaded through holes that are compatible with the external threads at the corresponding ends of the bidirectional screw; two limiting slide rails are symmetrically fixed at the bottom of the mounting groove, and the bottoms of the two slides are respectively provided with limiting slide grooves that slide with the two limiting slide rails.

[0017] Furthermore, the position adjustment mechanism includes two symmetrical transmission racks fixedly provided at the bottom of the support platform, and first horizontal plates are fixedly provided on both sides of the movable frame under the two first limit blocks, and third motors are fixedly provided at the bottom of the two first horizontal plates, and the output shafts of the two third motors respectively pass through the corresponding first horizontal plates and are provided with first gears meshing with the transmission racks on the corresponding sides; the two side limit plates are respectively fixedly provided with second horizontal plates under the two second limit blocks, and fourth motors are fixedly provided at the bottom of the two second horizontal plates, and the driving shafts of the two fourth motors respectively pass through the corresponding second horizontal plates and are provided with second gears meshing with the transmission racks on the corresponding sides.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] The distance between the two cheek pads and the position of the chin pad in the head support assembly of the present invention can be conveniently adjusted to meet the facial support needs of different patients. The positions of the trunk support assembly and the leg support assembly of the present invention on the support table can be moved and adjusted on the support table, so as to meet the support needs of patients with different heights, body lengths and different upper and lower body proportions when undergoing prone surgery. In addition, the bending angle changes at both ends of the trunk support pad of the present invention realize the convenient adjustment of the support angle of the patient's torso, thereby meeting the support needs of different surgical sites and procedures. In summary, the present invention can be flexibly adjusted according to the patient's body shape, surgical site and surgical requirements, avoiding the situation of local pressure concentration on the patient's body during prone surgery, and reducing the risk of pressure sores or nerve damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0022] Figure 2 It is the front view of the present invention;

[0023] Figure 3 A top view of the present invention;

[0024] Figure 4 A bottom view of the present invention;

[0025] Figure 5 It is a right side view of the present invention;

[0026] Figure 6 It is a left side view of the present invention;

[0027] Figure 7 is a schematic diagram of a trunk support assembly of the present invention;

[0028] Figure 8 is a schematic diagram of a leg support assembly of the present invention;

[0029] Explanation of reference numerals: 1, base; 2, support platform; 3, cheek rest pad; 4, mandibular rest pad; 5, first vertical plate; 6, first electric telescopic rod; 7, push-pull block; 8, connecting rod; 9, slide; 10, transverse slide; 11, second vertical plate; 12, second electric telescopic rod; 13, connecting plate; 14, slide block; 15, longitudinal slide; 16, moving frame; 17, slide plate; 18, first limit block; 19, trunk rest pad; 20, adjusting screw; 21, guide rod; 22, first motor; 23, driving shaft; 24. Driving bevel gear; 25. Driven bevel gear; 26. Lifting platform; 27. Support rod; 28. Fixed support plate; 29. ​​Movable support plate; 30. Foot support pad; 31. Side limit plate; 32. Second limit block; 33. Mounting slot; 34. Slide seat; 35. Leg support pad; 36. Bidirectional lead screw; 37. Second motor; 38. Limiting slide rail; 39. Transmission rack; 40. First horizontal plate; 41. Third motor; 42. First gear; 43. Second horizontal plate; 44. Fourth motor; 45. Second gear. DETAILED DESCRIPTION

[0030] like Figures 1-8 As shown, an adjustable body support device for prone surgery includes a base 1, and a horizontal support platform 2 is fixedly installed on the upper part of the base 1.

[0031] The upper part of the support platform 2 is provided with a head support assembly, a trunk support assembly and a leg support assembly in sequence.

[0032] The head support assembly includes two cheek pads 3 symmetrically slidably mounted on the support platform 2 and a chin pad 4 slidably mounted on the support platform 2 and located between the two cheek pads 3. A face width adjustment mechanism for adjusting the distance between the two cheek pads 3 is provided between the end of the support platform 2 and the two cheek pads 3, and a chin adjustment mechanism for driving the chin pad 4 to move is provided at the bottom of the support platform 2.

[0033] The facial width adjustment mechanism includes a first vertical plate 5 fixedly mounted in the middle of the end of the support platform 2 and a first electrically-operated telescopic rod 6 fixedly mounted horizontally on the outside of the first vertical plate 5. A push-pull block 7 is fixedly attached to the telescopic end of the first electrically-operated telescopic rod 6. The push-pull block 7 is hingedly connected to one end of two symmetrically arranged connecting rods 8. The ends of the two cheek rests 3, distal from the chin rest 4, are each fixedly connected to an L-shaped slide 9. One end of each slide 9 is fixedly connected to the corresponding cheek rest 3. The other ends of each slide 9 slidably engage with a transverse slot 10 defined in the support platform 2. The middle portions of each slide 9 are hingedly connected to the other ends of the two connecting rods 8. In this embodiment, the telescopic movement of the first electrically-operated telescopic rod 6 drives the push-pull block 7 to move linearly. This linear movement, driven by the two connecting rods, drives the two slides 9 to slide toward or away from each other within the transverse slot 10, thereby adjusting the spacing between the two cheek rests 3 to accommodate the facial support needs of patients with varying facial widths.

[0034] The mandibular adjustment mechanism includes a second vertical plate 11 fixedly disposed at the bottom of the support platform 2, a second electric telescopic rod 12 fixedly mounted on the second vertical plate 11, the telescopic end of the second electric telescopic rod 12 fixedly connected to a connecting plate 13, the upper end of the connecting plate 13 fixedly connected to the bottom of a slider 14, the middle portion of the slider 14 slidingly engaged with a longitudinal slot 15 provided on the support platform 2, and the upper portion of the slider 14 fixedly connected to the bottom middle portion of the mandibular support pad 4. In this embodiment, the telescopic action of the second electric telescopic rod 12 drives the connecting plate 13 and slider 14 to move linearly, thereby adjusting the position of the mandibular support pad 4 to accommodate the facial support needs of patients with different face lengths.

[0035] The trunk support assembly and the leg support assembly are both slidably arranged on the upper part of the support platform 2, and the upper part of the support platform 2 is provided with a position adjustment mechanism for driving the trunk support assembly and the leg support assembly to move.

[0036] The torso support assembly includes a movable frame 16 slidably mounted on the support platform 2. The cross-section of the movable frame 16 is an inverted U-shape and its two inner side walls are in contact with the two sides of the support platform 2 respectively. A slide plate 17 is fixedly provided inside the movable frame 16 and is flat against the upper surface of the support platform 2. First limit blocks 18 are fixedly provided on the two side panels of the movable frame 16 and are flat against the lower surface of the support platform 2 respectively. A torso support pad 19 is installed on the upper part of the movable frame 16.

[0037] An adjusting screw 20 is vertically rotatably installed between the slide 17 and the top plate of the movable frame 16, and two vertical guide rods 21 are symmetrically fixed along the adjusting screw 20 on the upper part of the slide 17. A first motor 22 for driving the adjusting screw 20 to rotate is installed on the outer side of the movable frame 16. Specifically: a horizontal driving shaft 23 is rotatably installed on one side of the first motor 22 installed on the upper part of the movable frame 16, one end of the driving shaft 23 is connected to the output end of the first motor 22, and the other end is installed with a driving bevel gear 24, and a driven bevel gear 25 adapted to the driving bevel gear 24 is installed on the upper part of the adjusting screw 20. When the first motor 22 is started, the adjusting screw 20 is rotated by the meshing transmission action of the driving bevel gear 24 on the driving shaft 23 and the driven bevel gear 25 on the adjusting screw 20.

[0038] A lifting platform 26 is mounted on both the adjustment screw 20 and the two guide rods 21. A threaded hole is provided in the middle of the lifting platform 26 to accommodate the adjustment screw 20, and apertures are provided at each end of the lifting platform 22 to slide with the two guide rods 21. Multiple support rods 27 are hingedly mounted at even intervals on either side of the lifting platform 26. A horizontal fixed support plate 28 is fixed to the top of the mobile frame 16. Two movable support plates 29 are symmetrically hinged at each end of the fixed support plate 28. The bottoms of the two movable support plates 29 are hingedly connected to the fixed support plate 28 via hinges. The bottoms of each movable support plate 29 are hingedly connected to the multiple support rods 27 on the corresponding side of the lifting platform 26. The center of the bottom of the trunk support pad 19 is fixedly connected to the fixed support plate 28, and the ends of the bottom of the trunk support pad 19 are fixedly connected to the two movable support plates 29.

[0039] The material of the torso support pad 19 is a bendable and deformable sponge pad or silicone pad. In this embodiment, the adjusting screw 20 is driven to rotate by the first motor 22. When the adjusting screw 20 rotates, it drives the lifting platform 26 threadedly connected to it to move linearly in the vertical direction. During the vertical movement of the lifting platform 26, the two movable support plates 29 are flipped relative to the fixed support plate 28 through the support rods 27 on both sides, thereby adjusting the bending angles of the two ends of the torso support pad 19, thereby realizing convenient adjustment of the support angle of the patient's torso to meet the support requirements of different surgical parts and procedures.

[0040] The leg support assembly includes a foot support pad 30 that is slidably mounted on the upper portion of the support platform 2. Two side limit plates 31 are fixedly mounted on the bottom and sides of the foot support pad 30, and are flatly attached to the two sides of the support platform 2. The two side limit plates 31 are respectively fixedly mounted with second limit blocks 32 that are flatly attached to the lower surface of the support platform 2. A mounting slot 33 is defined in the middle of the foot support pad 30. Two slides 34 are symmetrically mounted in the mounting slot 33 for sliding movement. The ends of the two slides 34, which are close to the torso support pad 19, extend to the outside of the foot support pad 30 and are fixedly mounted with leg support pads 35.

[0041] In this embodiment, a bidirectional screw 36 is rotatably mounted horizontally in the center of the mounting slot 33. A second motor 37 is mounted on the outside of the foot support 30 to drive the bidirectional screw 36. The two ends of the bidirectional screw 36 have external threads that rotate in opposite directions, and the two slides 34 each have a threaded through hole that mates with the corresponding external threads of the bidirectional screw 36. Two limiting rails 38 are symmetrically fixedly mounted at the bottom of the mounting slot 33. The bottoms of the two slides 34 each have a limiting groove that slidably engages with the two limiting rails 38.

[0042] In this embodiment, the second motor drives the bidirectional screw 36 to rotate. During the rotation of the bidirectional screw 36, the two slides 34 are driven to move toward or away from each other, thereby adjusting the distance between the two leg support pads 35 to meet the support requirements for the patient's legs under different surgical conditions.

[0043] In this embodiment, the position adjustment mechanism includes two symmetrical transmission racks 39 fixedly mounted on the bottom of the support platform 2 along the length direction of the support platform 2. First transverse plates 40 are fixedly mounted on both sides of the movable frame 16 below the two first limit blocks 18. Third motors 41 are fixedly mounted on the bottoms of the two first transverse plates 40. The output shafts of the two third motors 41 pass through the corresponding first transverse plates 40 and are equipped with first gears 42 at their ends that mesh with the transmission racks 39 on the corresponding sides. Second transverse plates 43 are fixedly mounted on the two side limit plates 31 below the two second limit blocks 32. Fourth motors 44 are fixedly mounted on the bottoms of the two second transverse plates 43. The drive shafts of the two fourth motors 44 pass through the corresponding second transverse plates 43 and are equipped with second gears 45 at their ends that mesh with the transmission racks 39 on the corresponding sides.

[0044] In this embodiment, two third motors 41 are used to respectively drive the two first gears 42 to rotate. During the rotation process, the two first gears 42 maintain a meshing relationship with the transmission racks 39 on the corresponding sides, thereby causing the movable frame 16 to move linearly along the length direction of the support table 2. In addition, in this embodiment, two fourth motors 44 are used to drive the two second gears 45 to rotate. During the rotation process, the two second gears 45 maintain a meshing relationship with the transmission racks 39 on the corresponding sides, thereby causing the foot support pad 30 to move along the length direction of the support table 2. In summary, this embodiment achieves position adjustment of the torso support pad and the foot support pad on the support table, thereby being able to adapt to the support needs of patients of different heights, body lengths, and different upper and lower body proportions when undergoing prone surgery.

[0045] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. An adjustable body support device for prone position surgery, characterized by: It comprises a base, wherein a horizontal support platform is fixedly provided on the upper part of the base; The upper part of the support platform is provided with a head support assembly, a trunk support assembly and a leg support assembly in sequence; The head support assembly includes two cheek pads symmetrically arranged on the support platform and a chin pad slidably arranged between the two cheek pads. A face width adjustment mechanism for adjusting the distance between the two cheek pads is provided between the end of the support platform and the two cheek pads. A chin adjustment mechanism for driving the chin pad to move is provided at the bottom of the support platform. The trunk support assembly and the leg support assembly are both slidably arranged on the upper part of the support platform, and the upper part of the support platform is provided with a position adjustment mechanism for driving the trunk support assembly and the leg support assembly to move.

2. The adjustable body support device for prone position surgery according to claim 1, characterized in that: The face width adjustment mechanism includes a first vertical plate fixedly arranged in the middle of the end portion of the support platform and a first electric telescopic rod fixedly arranged horizontally on the outside of the first vertical plate, the telescopic end of the first electric telescopic rod is fixedly provided with a push-pull block, and the push-pull block is hingedly connected to one end of two symmetrically arranged connecting rods; the ends of the two cheek pads away from the mandibular pad are respectively fixedly connected to the L-shaped slide, one end of the two slides is respectively fixedly connected to the corresponding cheek pads, the other ends of the two slides are slidably matched with the horizontal slide groove opened on the support platform, and the middle parts of the two slides are respectively hingedly connected to the other ends of the two connecting rods.

3. The adjustable body support device for prone position surgery according to claim 1, characterized in that: The mandibular adjustment mechanism includes a second vertical plate fixedly arranged on the bottom of the support platform, a second electric telescopic rod is fixedly arranged on the second vertical plate, the telescopic end of the second electric telescopic rod is fixedly connected to the connecting plate, the upper end of the connecting plate is fixedly connected to the bottom of the slider, the middle part of the slider is slidably matched with the longitudinal slide groove opened on the support platform, and the upper part of the slider is fixedly connected to the middle of the bottom of the mandibular support pad.

4. The adjustable body support device for prone position surgery according to claim 1, characterized in that: The torso support assembly includes a movable frame slidably arranged on the support platform, the cross-section of the movable frame is an inverted U-shape and its two inner side walls are respectively in contact with the two sides of the support platform, a slide plate is fixedly arranged inside the movable frame and is flat against the upper surface of the support platform, and first limit blocks are respectively fixedly arranged on the two side panels of the movable frame and are flat against the lower surface of the support platform; a torso support pad is provided on the upper part of the movable frame.

5. The adjustable body support device for prone position surgery according to claim 4, characterized in that: Material toggling mechanism, its both sides respectively have a cylinder pressure, and the cylinder pressure bar connects swing arm, and the swing arm end face has hook portion, and a bar passes position between the end of two swing arms and the hook portion.

6. The adjustable body support device for prone position surgery according to claim 5, characterized in that: The trunk support pad is made of a flexible and deformable sponge pad or a silicone pad.

7. The adjustable body support device for prone position surgery according to claim 5, characterized in that: The upper part of the movable frame is provided with a horizontal driving shaft which is rotated on one side of the first motor. One end of the driving shaft is connected to the output end of the first motor, and the other end is provided with a driving bevel gear. The upper part of the adjusting screw is provided with a driven bevel gear which is adapted to the driving bevel gear.

8. The adjustable body support device for prone position surgery according to claim 4, characterized in that: The leg support assembly includes a foot support pad that is slidably arranged on the upper part of the support platform, and two side limit plates that are flat on both sides of the support platform are fixedly provided at both sides of the bottom of the foot support pad, and the two side limit plates are respectively fixed with second limit blocks that are flat on the lower surface of the support platform; an installation groove is opened in the middle of the foot pad, and two sliding seats are symmetrically slidably arranged in the installation groove, and the two sliding seats extend to the outside of the foot support pad at one end close to the torso support pad and are fixed with leg support pads.

9. The adjustable body support device for prone position surgery according to claim 8, characterized in that: A bidirectional lead screw is provided for rotating horizontally in the middle of the internal part of the mounting groove, and a second motor for driving the bidirectional lead screw to rotate is provided on the outer side of the foot support pad; the external threads at both ends of the bidirectional lead screw rotate in opposite directions, and the two slides are respectively provided with threaded through holes that are compatible with the external threads at the corresponding ends of the bidirectional screw; two limiting slide rails are symmetrically fixed at the bottom of the mounting groove, and the bottoms of the two slides are respectively provided with limiting slide grooves that slide with the two limiting slide rails.

10. The adjustable body support device for prone position surgery according to claim 9, characterized in that: The position adjustment mechanism includes two symmetrical transmission racks fixedly arranged at the bottom of the support platform, and first horizontal plates are fixedly arranged on both sides of the movable frame under the two first limit blocks, and third motors are fixedly arranged at the bottom of the two first horizontal plates, and the output shafts of the two third motors respectively pass through the corresponding first horizontal plates and are provided with first gears meshing with the transmission racks on the corresponding sides; the two side limit plates are respectively fixedly provided with second horizontal plates under the two second limit blocks, and fourth motors are fixedly arranged at the bottom of the two second horizontal plates, and the driving shafts of the two fourth motors respectively pass through the corresponding second horizontal plates and are provided with second gears meshing with the transmission racks on the corresponding sides.