Multi-zone support independent adjustment care cushion

Abstract

This utility model discloses a multi-zone support independently adjustable nursing seat cushion. It includes a seat cushion with a tailbone support air cushion, a hip support air cushion, a leg support air cushion, and a front leg auxiliary support pad on its support end face. An ischial support pad is located adjacent to the hip and leg support air cushions. The tailbone support air cushion is positioned at the rear center of the hip support air cushion, and the leg support air cushion is positioned in front of the hip support air cushion. A groin ventilation chamber is provided between the leg and hip support air cushions. The front leg auxiliary support pad is horizontally positioned in front of the leg support air cushion. The tailbone, hip, and leg support air cushions are connected to a segmented adjustment push switch via air tubes. The segmented adjustment push switch has an inflation / deflation port. The advantages of this utility model include: providing corresponding support structures for the different force requirements of different parts of the body when sitting, and the independent adjustment of the support air pressure in each adjustable air chamber.

Description

Technical Field

[0001] This utility model relates to the field of nursing products technology, and more specifically, to a multi-zone support and independently adjustable nursing seat cushion. Background Technology

[0002] Seat cushions are support accessories that fit into chairs, wheelchairs, etc., primarily serving people who sit for long periods, and are especially optimized for care settings. Existing seat cushions come in various styles, most using foam or memory foam as internal filling to cover the buttocks and thighs, providing flexible seating support, and are suitable for home, medical, and other scenarios.

[0003] Existing ordinary foam comfort seat cushions have three major problems in practical applications. First, they have poor support adaptability. Most are made of a single piece of fixed-density foam, which cannot meet the needs of people with different weights. Lighter people are prone to sinking in, causing their lower back to be unsupported, while heavier people experience localized pressure overload, exacerbating the risk of pressure sores. Second, they have insufficient breathability and heat dissipation. The sealed fabric and high-density foam block air circulation, and after sitting for a long time, heat and sweat easily accumulate in the buttocks and thigh areas, causing skin dampness and eczema. Third, they have poor durability. After long-term pressure, the foam is prone to localized collapse, losing its support effect and failing to meet the care needs of people who sit for long periods of time.

[0004] Therefore, there is a need to develop a nursing seat cushion with a novel structure to meet different nursing and seating needs. Utility Model Content

[0005] The purpose of this invention is to solve the problems existing in the use of the above-mentioned existing cushions, and to provide a multi-zone support and independently adjustable care cushion that is easy to use and can be independently designed and adjusted to meet the needs of different parts of the human body.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A multi-zone support, independently adjustable nursing seat cushion includes a seat cushion with a tailbone support air cushion, a hip support air cushion, a leg support air cushion, and a front leg auxiliary support pad on its support end face. An ischial support pad is located adjacent to the hip support air cushion and the leg support air cushion. The hip support air cushion includes two connected and symmetrically arranged elliptical air cushions. The tailbone support air cushion is located at the middle of the rear end of the hip support air cushion, between the two elliptical air cushions. The leg support air cushion is located on the front side of the hip support air cushion. The seat has an outwardly expanding arc-shaped structure. A crotch ventilation chamber is provided between the leg support air cushion and the buttock support air cushion. The front leg auxiliary support cushion is horizontally arranged on the front side of the leg support air cushion. The upper end of the front leg auxiliary support cushion has two leg placement grooves. The tailbone support air cushion and the buttock support air cushion are connected to a segmented adjustment push switch via an air tube. The segmented adjustment push switch is provided with an inflation / deflation port. The segmented adjustment push switch includes a toggle slide and a toggle adjustment slider installed in the toggle slide. The air tube is fitted inside the seat cushion.

[0007] Preferably, the actuating slide includes an inflation / deflation switch slot, a locking switch slot, a tailbone support air cushion adjustment slot, a hip support air cushion adjustment slot, and a leg support air cushion adjustment slot. The inflation / deflation switch slot is connected to the tailbone support air cushion, the hip support air cushion, and the leg support air cushion. The tailbone support air cushion adjustment slot is connected to the tailbone support air cushion, the hip support air cushion adjustment slot is connected to the hip support air cushion, and the leg support air cushion adjustment slot is connected to the leg support air cushion.

[0008] Preferably, the leg support air cushion includes a first leg support part, a second leg support part, and a third leg support part arranged sequentially, wherein the height of the support surface of the second leg support part is lower than the height of the support surfaces of the first leg support part and the third leg support part.

[0009] Preferably, the outer side of the leg support air cushion is provided with an anti-tilt support air cushion, and the support surface of the anti-tilt support air cushion is an inclined concave arc-shaped support surface.

[0010] Preferably, the seat cushion is provided with ventilation holes, which are located on the outer side of the tailbone support air cushion, the buttock support air cushion, the leg support air cushion and the foreleg auxiliary support air cushion.

[0011] Preferably, the upper surface of the ischial support pad is provided with a breathable and abrasion-resistant surface.

[0012] Preferably, the back support plate is connected to the rear side of the seat cushion. The back support plate has an L-shaped structure and an arc-shaped support surface. The connecting part of the back support plate is located below the buttock support air cushion of the seat cushion.

[0013] Preferably, the back auxiliary support plate has a soft support protrusion in the middle of the arc-shaped support surface.

[0014] Preferably, the front leg auxiliary support pad is detachably installed on the seat cushion. The bottom of the front leg auxiliary support pad is provided with a combined protrusion, and the combined protrusion is provided with a combined limiting groove in the middle. The seat cushion is provided with a combined locking hole. The combined protrusion and the combined locking hole are in a limiting fit, and the combined limiting groove and the combined locking hole are in a limiting fit.

[0015] Compared with the prior art, the advantages of this invention include: This invention features corresponding support structures designed to meet the different stress requirements of various parts of the body when seated, providing users with a more comfortable seating experience. It also includes independent adjustable air chambers for each area, with the air pressure in each chamber adjustable to the user's needs via a segmented push-button switch. This enhances the seating experience while significantly reducing the risk of pressure sores caused by prolonged sitting, thus better protecting the user. An anti-tipping support air cushion is also included on the outer side of the leg support air cushion, providing better lateral support and preventing the user from tipping over and falling. Furthermore, a back support plate conforming to the natural curve of the lower back is located at the back of the seat, allowing the user to relax their back during seating, reducing lumbar muscle strain, and preventing excessive pressure on the lower back caused by prolonged unsupported posture. This design allows for better and more comfortable seating, avoiding problems such as unsupported lower back and uneven pressure on the thighs. This invention is lightweight, easy to inflate and deflate, breathable, and widely applicable. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model.

[0017] Figure 2 This is a side view of the structure of this utility model.

[0018] Figure 3 This is a schematic diagram of the combined structure of the front leg auxiliary support pad and the seat cushion of this utility model.

[0019] Figure 4 This is a structural schematic diagram of the second embodiment of the present invention.

[0020] Explanation of icon numbers: Seat cushion-1, tailbone support air cushion-2, hip support air cushion-3, leg support air cushion-4, foreleg auxiliary support cushion-5, ischium support cushion-6, crotch ventilation cavity-7, segmented adjustment push switch-8, back auxiliary support plate-9, ventilation hole-11, air tube-12, combination locking hole-13, oval air cushion-31, first leg support section-41, second leg support section-42, third leg support section-43, anti-tilt support air cushion-44, concave Arc-shaped support surface - 45, combined protruding column - 51, combined limiting groove - 52, leg placement groove - 53, breathable and abrasion-resistant surface - 61, sliding groove - 81, sliding adjustment slider - 82, inflation / deflation port - 83, inflation / deflation switch groove - 811, locking switch groove - 812, tailbone support air cushion adjustment groove - 813, hip support air cushion adjustment groove - 814, leg support air cushion adjustment groove - 815, soft support protruding strip - 91, arc-shaped support surface - 92. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0022] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0023] The present invention will be further described below with reference to specific embodiments and accompanying drawings: Figures 1 to 4These are schematic diagrams of the various structures of this utility model. Further, this utility model is a multi-area support independently adjustable nursing seat cushion, including a seat cushion 1. The supporting end face of the seat cushion 1 is provided with a coccyx support air cushion 2, a hip support air cushion 3, a leg support air cushion 4, and a front leg auxiliary support cushion 5. An ischium support cushion 6 is provided adjacent to the hip support air cushion 3 and the leg support air cushion 4. The hip support air cushion 3 includes two connected and symmetrically arranged elliptical air cushions 31. The coccyx support air cushion is located at the middle of the rear end of the hip support air cushion 3, with the coccyx support air cushion positioned between the two elliptical air cushions 31. The leg support air cushion 4 is located on the front side of the hip support air cushion 3. The cushion 4 has an outwardly expanding arc-shaped structure. A crotch ventilation cavity 7 is provided between the leg support air cushion 4 and the buttock support air cushion 3. The front leg auxiliary support cushion 5 is arranged horizontally on the front side of the leg support air cushion 4. The upper end of the front leg auxiliary support cushion 5 is provided with two leg placement grooves 53. The tailbone support air cushion 2, the buttock support air cushion 3, and the leg support air cushion 4 are connected to the segmented adjustment push switch 8 through the air pipe 12. The segmented adjustment push switch 8 is provided with an inflation / deflation port 83. The segmented adjustment push switch 8 includes a toggle slide 81 and a toggle adjustment slider 82 installed in the toggle slide 81. The air pipe 12 is fitted inside the seat cushion 1.

[0024] Preferably, the actuating slide 81 includes an inflation / deflation switch 811, a locking switch 812, a tailbone support air cushion adjustment 813, a hip support air cushion adjustment 814, and a leg support air cushion adjustment 815. The inflation / deflation switch 811 is connected to the tailbone support air cushion 2, the hip support air cushion 3, and the leg support air cushion 4. The tailbone support air cushion adjustment 813 is connected to the tailbone support air cushion 2. The hip support air cushion adjustment 814 is connected to the hip support air cushion 3. The leg support air cushion adjustment 815 is connected to the leg support air cushion 4.

[0025] Preferably, the leg support air cushion 4 includes a first leg support part 41, a second leg support part 42 and a third leg support part 43 arranged in sequence, wherein the height of the support surface of the second leg support part 42 is lower than the height of the support surfaces of the first leg support part 41 and the third leg support part 43.

[0026] Preferably, the outer side of the leg support air cushion 4 is provided with an anti-tilt support air cushion 44, and the support surface of the anti-tilt support air cushion 44 is an inclined concave arc-shaped support surface 45.

[0027] Preferably, the seat cushion 1 is provided with ventilation holes 11, which are located on the outer side of the tailbone support air cushion 2, the buttock support air cushion 3, the leg support air cushion 4 and the front leg auxiliary support cushion 5.

[0028] Preferably, the upper surface of the ischial support pad 6 is provided with a breathable and abrasion-resistant surface 61.

[0029] Preferably, the back support plate 9 is connected to the rear side of the seat cushion 1. The back support plate 9 has an L-shaped structure and an arc-shaped support surface 92. The connecting part of the back support plate 9 is located below the buttock support air cushion 3 of the seat cushion 1.

[0030] Preferably, the back auxiliary support plate 9 has a soft support protrusion 91 in the middle of the arc-shaped support surface 92.

[0031] Preferably, the front leg auxiliary support pad 5 is detachably installed on the seat cushion 1. The bottom of the front leg auxiliary support pad 5 is provided with a combined protrusion 51, and the combined protrusion 51 is provided with a combined limiting groove 52 in the middle. The seat cushion 1 is provided with a combined locking hole 13. The combined protrusion 51 and the combined locking hole 13 are in a limited fit, and the combined limiting groove 52 and the combined locking hole 13 are in a limited fit.

[0032] First embodiment: A multi-zone support, independently adjustable nursing seat cushion includes a seat cushion 1. The support end face of the seat cushion 1 is provided with a coccyx support air cushion 2, a hip support air cushion 3, a leg support air cushion 4, and a front leg auxiliary support pad 5. An ischial support pad 6 is provided adjacent to the hip support air cushion 3 and the leg support air cushion 4. The hip support air cushion 3 includes two connected and symmetrically arranged elliptical air cushions 31, with the support air cushion located at the middle of the rear end of the hip support air cushion 3, between the two elliptical air cushions 31. The leg support air cushion 4 is located on the front side of the hip support air cushion 3 and is an outwardly flared arc shape. The structure includes a crotch ventilation chamber 7 between the leg support air cushion 4 and the buttock support air cushion 3. The front leg auxiliary support cushion 5 is horizontally positioned on the front side of the leg support air cushion 4. The upper end of the front leg auxiliary support cushion 5 is provided with two leg placement grooves 53. The tailbone support air cushion 2, the buttock support air cushion 3, and the leg support air cushion 4 are connected to the segmented adjustment push switch 8 through the air pipe 12. The segmented adjustment push switch 8 is provided with an inflation / deflation port 83. The segmented adjustment push switch 8 includes a toggle slide 81 and a toggle adjustment slider 82 installed in the toggle slide 81. The air pipe 12 is fitted inside the seat cushion 1.

[0033] Furthermore, the sliding groove 81 includes an inflation / deflation switch groove 811, a locking switch groove 812, a tailbone support air cushion adjustment groove 813, a hip support air cushion adjustment groove 814, and a leg support air cushion adjustment groove 815. The inflation / deflation switch groove 811 is connected to the tailbone support air cushion 2, the hip support air cushion 3, and the leg support air cushion 4. The tailbone support air cushion adjustment groove 813 is connected to the tailbone support air cushion 2, the hip support air cushion adjustment groove 814 is connected to the hip support air cushion 3, and the leg support air cushion adjustment groove 815 is connected to the leg support air cushion 4.

[0034] Furthermore, the leg support air cushion 4 includes a first leg support part 41, a second leg support part 42, and a third leg support part 43 arranged sequentially. The height of the support surface of the second leg support part 42 is lower than the height of the support surfaces of the first leg support part 41 and the third leg support part 43.

[0035] Furthermore, an anti-tilt support air cushion 44 is provided on the outer side of the leg support air cushion 4, and the support surface of the anti-tilt support air cushion 44 is an inclined concave arc-shaped support surface 45.

[0036] When in use, the inflation / deflation port 83 of the seat cushion is connected to the inflation device. The sliding slider 82 of the segmented adjustment push switch 8 is adjusted to the inflation / deflation switch slot 811 position. The inflation device is started to inflate the tailbone support air cushion 2, the buttock support air cushion 3, and the leg support air cushion 4. After inflation is completed, the inflation device is turned off and the sliding slider 82 is adjusted to the locking switch slot 812 position to lock the support air pressure of the tailbone support air cushion 2, the buttock support air cushion 3, and the leg support air cushion 4. When different users have different needs for support in different areas, they can adjust the slider 82 to the tailbone support air cushion adjustment slot 813, hip support air cushion adjustment slot 814, or leg support air cushion adjustment slot 815. The corresponding tailbone support air cushion 2, hip support air cushion 3, and leg support air cushion 4 can be inflated or deflated according to the support requirements. When firmer support is needed, the corresponding tailbone support air cushion 2, hip support air cushion 3, and leg support air cushion 4 can be inflated to increase the support level. The support strength of the tailbone support air cushion 3 and leg support air cushion 4 provides users with sufficient and effective support when sitting. When only softer auxiliary support is needed for the tailbone, buttocks, or legs, the corresponding tailbone support air cushion 2, buttock support air cushion 3, and leg support air cushion 4 can be compressed and deflated to reduce the support force in each area. This allows users to receive support while maintaining appropriate breathability, preventing pressure sores and better protecting the user.

[0037] Furthermore, an ischial support pad 6 is provided adjacent to the hip support air cushion 3 and the leg support air cushion 4 to ensure sufficient stable support for the user's ischial tuberosities. Simultaneously, a groin ventilation chamber 7 is provided between the leg support air cushion 4 and the hip support air cushion 3, allowing users who need to sit for extended periods to keep their groin dry and breathable, preventing stuffiness caused by prolonged sitting. Additionally, a front leg auxiliary support pad 5 with two leg placement grooves 53 is horizontally positioned on the front side of the leg support air cushion 4, providing sufficient support for the front of the thighs while sitting, preventing sagging or dangling and increasing pressure on the legs.

[0038] Furthermore, the leg support air cushion 4 includes a first leg support part 41, a second leg support part 42, and a third leg support part 43 arranged sequentially. The height of the support surface of the second leg support part 42 is lower than the height of the support surfaces of the first leg support part 41 and the third leg support part 43. Dividing the leg support air cushion 4 into three independent support parts provides more comfortable segmented support for the legs. Combined with the support heights of the first leg support part 41, the second leg support part 42, and the third leg support part 43, which conform to the shape of the legs, the support needs of different areas of the legs are met.

[0039] Second embodiment: This embodiment is similar to the first embodiment, except that an anti-tilt support air cushion 44 is provided on the outer side of the leg support air cushion 4 in this embodiment. The support surface of the anti-tilt support air cushion 44 is an inclined concave arc-shaped support surface 45. The cooperation between the anti-tilt support air cushion 44 and the concave arc-shaped support surface 45 allows the user to have better support on both sides when sitting, preventing the user from accidentally tilting and falling while sitting, and providing a more effective protection effect. Furthermore, the seat cushion 1 is provided with ventilation holes 11, which are located on the outer side of the coccyx support air cushion 2, the buttock support air cushion 3, the leg support air cushion 4, and the front leg auxiliary support pad 5. The ventilation holes 11 are evenly distributed on the seat cushion 1 to improve the overall breathability of the seat cushion, helping the user to keep the legs and the bottom of the seat cushion dry and breathable during long-term sitting. Preferably, the upper surface of the ischial tuberosity support pad 6 is provided with a breathable and anti-abrasion surface 61. While providing sufficient support to the ischial tuberosity, it can also protect the lower end of the ischial tuberosity from abrasion or pressure sores during sitting.

[0040] Third embodiment: This embodiment is similar to the above embodiment, except that in this embodiment, the back support plate 9 is connected to the rear side of the seat cushion 1. The back support plate 9 has an L-shaped structure and an arc-shaped support surface 92. The connecting part of the back support plate 9 is located below the buttock support air cushion 3 of the seat cushion 1. Furthermore, a soft support protrusion 91 is provided in the middle of the arc-shaped support surface 92 of the back support plate 9.

[0041] It can provide users with sitting support while effectively supporting their back, reducing the pressure on the back during sitting and allowing the lower back to relax properly. In conjunction with the soft support protrusion 91 in the middle of the curved support surface 92, it can also provide more comfortable contact support for the spine when the user leans their back against the back support plate 9.

[0042] Furthermore, the front leg auxiliary support pad 5 is detachably installed on the seat cushion 1. The bottom of the front leg auxiliary support pad 5 has a combined protrusion 51, and the combined protrusion 51 has a combined limiting groove 52 in the middle. The seat cushion 1 has a combined locking hole 13. The combined protrusion 51 and the combined locking hole 13 are fitted together, and the combined limiting groove 52 and the combined locking hole 13 are mutually limitingly engaged. The front leg auxiliary support pad 5 and the seat cushion 1 are detachable. After use, the front leg auxiliary support pad 5 can be removed for cleaning or replacement according to usage. After completion, the front leg auxiliary support pad 5 can be reinstalled on the seat cushion 1 through the combination structure of the combined protrusion 51 and the combined locking hole 13.

[0043] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A multi-zone support, independently adjustable nursing seat cushion, characterized in that, The cushion includes a seat (1), the supporting end face of which is provided with a coccyx support air cushion (2), a hip support air cushion (3), a leg support air cushion (4) and a front leg auxiliary support pad (5). An ischial support pad (6) is provided adjacent to the hip support air cushion (3) and the leg support air cushion (4). The hip support air cushion (3) includes two connected and symmetrically arranged elliptical air cushions (31). The coccyx support air cushion (2) is located at the middle of the rear end of the hip support air cushion (3), and is positioned between the two elliptical air cushions (31). The leg support air cushion (4) is located on the front side of the hip support air cushion (3), and has an outwardly expanding arc-shaped structure. A crotch ventilation cavity (7) is provided between the support air cushion (4) and the buttock support air cushion (3). The front leg auxiliary support cushion (5) is arranged horizontally on the front side of the leg support air cushion (4). The upper end of the front leg auxiliary support cushion (5) is provided with two leg placement grooves (53). The tailbone support air cushion (2), the buttock support air cushion (3), and the leg support air cushion (4) are connected to the segmented adjustment push switch (8) through the air pipe (12). The segmented adjustment push switch (8) is provided with an inflation / deflation port (83). The segmented adjustment push switch (8) includes a toggle slide (81) and a toggle adjustment slider (82) installed in the toggle slide (81). The air pipe (12) is fitted inside the seat cushion (1).

2. The multi-zone support independently adjustable nursing seat cushion according to claim 1, characterized in that, The actuating slide (81) includes an inflation / deflation switch slot (811), a locking switch slot (812), a tailbone support air cushion adjustment slot (813), a hip support air cushion adjustment slot (814), and a leg support air cushion adjustment slot (815). The inflation / deflation switch slot (811) is connected to the tailbone support air cushion (2), the hip support air cushion (3), and the leg support air cushion (4). The tailbone support air cushion adjustment slot (813) is connected to the tailbone support air cushion (2), the hip support air cushion adjustment slot (814) is connected to the hip support air cushion (3), and the leg support air cushion adjustment slot (815) is connected to the leg support air cushion (4).

3. A multi-zone support independently adjustable nursing seat cushion according to any one of claims 1 or 2, characterized in that, The leg support air cushion (4) includes a first leg support part (41), a second leg support part (42) and a third leg support part (43) arranged in sequence. The height of the support surface of the second leg support part (42) is lower than the height of the support surface of the first leg support part (41) and the third leg support part (43).

4. The multi-zone support independently adjustable nursing seat cushion according to claim 3, characterized in that, The leg support air cushion (4) is provided with an anti-tilt support air cushion (44) on the outside, and the support surface of the anti-tilt support air cushion (44) is an inclined concave arc support surface (45).

5. A multi-zone support independently adjustable nursing seat cushion according to claim 4, characterized in that, The seat cushion (1) is provided with ventilation holes (11), which are located on the outer side of the tailbone support air cushion (2), the hip support air cushion (3), the leg support air cushion (4) and the front leg auxiliary support cushion (5).

6. A multi-zone support independently adjustable nursing seat cushion according to claim 5, characterized in that, The upper surface of the ischial support pad (6) is provided with a breathable and abrasion-resistant surface (61).

7. A multi-zone support independently adjustable nursing seat cushion according to claim 3, characterized in that, The back support plate (9) is connected to the back side of the seat cushion (1). The back support plate (9) has an L-shaped structure and an arc-shaped support surface (92) on it. The connecting part of the back support plate (9) is located below the buttock support air cushion (3) of the seat cushion (1).

8. A multi-zone support independently adjustable nursing seat cushion according to claim 7, characterized in that, The back auxiliary support plate (9) has a soft support protrusion (91) in the middle of the arc-shaped support facade (92).

9. A multi-zone support independently adjustable nursing seat cushion according to any one of claims 1 or 2, characterized in that, The front leg auxiliary support pad (5) is detachably installed on the seat cushion (1). The bottom of the front leg auxiliary support pad (5) is provided with a combined protrusion (51). The combined protrusion (51) is provided with a combined limiting groove (52) in the middle. The seat cushion (1) is provided with a combined locking hole (13). The combined protrusion (51) is in the combined locking hole (13), and the combined limiting groove (52) is in a limiting fit with the combined locking hole (13).

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