Strength assisting mechanism of fitness equipment

Abstract

The invention discloses a strength assisting mechanism of fitness equipment, and relates to the technical field of fitness equipment, the strength assisting mechanism comprises a support frame, an assisting mechanism is fixedly mounted on the rear side of the top of the support frame, a sliding seat plate is slidably connected to the rear side of the inner surface of the support frame, and a sliding pedal is slidably connected to the front side of the inner surface of the support frame; and a foot fixer is fixedly mounted at the top of the sliding pedal. When a user sits up, the user can sit on the sliding seat plate, when the user lies down, a first sponge mat on the supporting plate is squeezed, a rotating column can drive a volute spiral spring to contract through a rotating rod, and therefore when the user sits up, the user can sit up through the elastic force of the volute spiral spring, and the user can sit up conveniently. According to the sit-up training device, the rotating rod can provide pushing assistance for the back of a user through the supporting plate and the first sponge mat, the user can conduct sit-up training more conveniently, the pushing position of the supporting plate can be limited through the limiting mechanism, and the sit-up training is more comfortable and efficient.

Description

Technical Field

[0001] The invention relates to the technical field of fitness equipment, and in particular to a power assisting mechanism of fitness equipment. Background Art

[0002] The power assist mechanism of fitness equipment is a mechanical or electronic device designed to assist users in reducing their burden and improving training effects during exercise, helping users to better achieve their fitness goals and making each exercise more efficient, safe and enjoyable.

[0003] The existing technology has the following problems: When doing sit-ups, users are often required to rely entirely on their own strength to complete the movement, which not only places extremely high demands on the core muscles, but also easily leads to sports injuries, especially excessive pressure on the waist and neck. In order to solve this problem, the present invention proposes a power assist mechanism of a fitness equipment for sit-ups, which aims to make sit-up training more scientific, comfortable and efficient through intelligent mechanical assistance. Summary of the invention

[0004] The present invention provides a power assisting mechanism of fitness equipment to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A power assist mechanism of fitness equipment comprises a support frame, a power assist mechanism is fixedly installed on the top rear side of the support frame, a sliding seat plate is slidably connected to the rear side of the inner surface of the support frame, a sliding pedal is slidably connected to the front side of the inner surface of the support frame, a foot holder is fixedly installed on the top of the sliding pedal, and connecting grooves are provided on the left and right sides of the inner wall of the support frame.

[0006] The power-assisting mechanism includes two connecting columns, which are respectively fixedly connected to the left and right rear sides of the top of the support frame. A rotating groove is provided on the top of the connecting column, and a rotating column is rotatably connected inside the rotating groove. A volute spring is fixedly connected to the middle of the opposite surfaces of the two rotating columns, and one end of the volute spring away from the rotating column is fixedly connected to the inner wall of the rotating groove. A rotating rod is fixedly connected to the rear side of the top of the outer surface of the two rotating columns, and the rear ends of the two rotating rods are fixedly connected to a support plate, and a sponge pad is fixedly connected to the middle of the outer surface of the support plate, and a limiting mechanism is provided on the inner wall of the rotating groove.

[0007] The foot fixer includes a connecting sleeve, which is fixedly connected to the top of the support frame, and a telescopic sliding column is slidably inserted at the top of the inner surface of the connecting sleeve. The left and right sides of the outer surfaces of the connecting sleeve and the telescopic sliding column are fixedly connected with connecting rods, and the outer surface of the connecting rod is fixedly connected with a second sponge pad.

[0008] A further improvement of the technical solution of the present invention is that the limiting mechanism includes a sliding column, and the two sliding columns are movably connected to the opposite sides of the two connecting columns respectively. A movable groove is opened inside the connecting column, and one end of the sliding column close to the connecting column penetrates into the movable groove and is fixedly connected to a tightening spring, and one end of the sliding column close to the tightening spring is fixedly connected to a U-shaped rotating frame.

[0009] A further improvement of the technical solution of the present invention is that both ends of the U-shaped rotating frame penetrate into the interior of the rotating groove and are fixedly connected to a ring-shaped rotating plate, the front of the ring-shaped rotating plate away from the U-shaped rotating frame is fixedly connected to a limiting stop column, the front and rear sides of the U-shaped rotating frame away from the ring-shaped rotating plate are fixedly connected to positioning columns, a ring-shaped array is provided on the inner wall of the movable groove, and the end of the positioning column away from the U-shaped rotating frame penetrates into the interior of the positioning groove.

[0010] A further improvement of the technical solution of the present invention is that the sliding seat plate includes a support plate, and the left and right sides of the support plate are fixedly connected with connecting slides, and the connecting slide is slidably connected to the inside of the connecting slide groove, and the front and rear sides of the inside of the connecting slide are movably connected with sliding wheels that penetrate up and down.

[0011] A further improvement of the technical solution of the present invention is that a knob 1 is movably connected below the rear end of the support plate, a bidirectional screw is fixedly connected to the front end of the knob 1, the bidirectional screw is movably connected to the bottom of the support plate, and threaded sliders are threadedly connected on both the front and rear sides of the outer surface of the bidirectional screw, and the upper surface of the threaded slider is slidably connected to the lower surface of the support plate.

[0012] A further improvement of the technical solution of the present invention is that: the left and right sides of the threaded slider are movably connected with pushing rods, and the two pushing rods on the same side are movably connected with a sliding push plate at one end away from the threaded slider, a sliding groove is opened in the middle of the side of the connecting slide away from the support plate, the sliding push plate is slidably connected to the lower surface of the support plate, the end of the sliding push plate away from the support plate penetrates into the interior of the sliding groove and is fixedly connected with a fixed pressure plate, and the outer surface of the fixed pressure plate is slidably connected to the inner surface of the sliding groove.

[0013] A further improvement of the technical solution of the present invention is that the telescopic sliding column includes a lifting column, the lifting column is slidably inserted above the inner surface of the connecting sleeve, the top of the lifting column is movably connected to a knob 2, and the bottom of the knob 2 is fixedly connected to a transmission screw.

[0014] A further improvement of the technical solution of the present invention is that a square slide groove is provided at the bottom end of the lifting column, the bottom end of the transmission screw penetrates into the interior of the square slide groove and is threadedly connected to a square column on the outer surface, the outer surface of the square column is slidably connected to the inner surface of the square slide groove, the bottom end of the square column is fixedly connected to the lower surface of the inner wall of the connecting sleeve, limiting slide grooves are provided on the front and rear sides of the outer surface of the square column, and limiting sliders are fixedly connected to the lower parts of the front and rear sides of the inner wall of the square slide groove, and the limiting slider is slidably connected to the inside of the limiting slide groove.

[0015] Due to the adoption of the above technical solution, the present invention has the following technical advances compared with the prior art: The present invention provides a power assisting mechanism of fitness equipment. Through the mutual cooperation among a connecting column, a rotating column, a spiral spring, a rotating rod, a support plate, a sponge pad and a limiting mechanism, a user sits on a sliding seat plate when doing sit-ups. When the user lies down, the sponge pad on the support plate is squeezed, and the rotating column can drive the spiral spring to contract through the rotating rod. Therefore, when the user sits up, the elastic force of the spiral spring can enable the rotating rod to provide a pushing assist to the back of the user through the support plate and the sponge pad, so that the user can perform sit-up training more conveniently. The pushing position of the support plate and the sponge pad can be limited through the limiting mechanism, so that the sit-up training is more scientific, comfortable and efficient.

[0016] The present invention provides a power assisting mechanism of fitness equipment. Through the mutual cooperation among a supporting plate, a connecting slide plate, a sliding wheel, a knob 1, a bidirectional screw, a threaded slider, a pushing rod, a sliding push plate, and a fixed pressing plate, the position of the sliding seat plate can be adjusted by sliding the connecting slide plate and the sliding wheel in a connecting slide groove, which is convenient for users of different heights to use. At the same time, by rotating the knob 1, the bidirectional screw can drive the threaded slide plate to slide, so that the sliding push plate can be pushed to slide by the pushing rod, so that the fixed pressing plate can press the inner wall of the connecting slide groove, so that the position of the sliding seat plate can be fixed, making the use of the power assisting mechanism for sit-ups more convenient.

[0017] The present invention provides a power assisting mechanism of fitness equipment. Through the mutual cooperation among a connecting sleeve, a lifting column, a second knob, a transmission screw, a square column, a limiting slide groove, a limiting slider, a connecting rod and a second sponge pad, a user can fix his feet between the connecting rod and the second sponge pad while doing sit-ups, making the sit-up training more comfortable. At the same time, by rotating the second knob, the lifting column can be driven to be lifted and lowered along the connecting sleeve through the threaded transmission of the transmission screw and the square column, so that the positions of the top connecting rod and the second sponge pad can be adjusted, which is convenient for different users to use and convenient for different users to do sit-up training. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a structural schematic diagram of the power assist mechanism of the present invention; Figure 3 It is an enlarged structural schematic diagram of the power-assisting mechanism of the present invention; Figure 4 It is a structural schematic diagram of the sliding seat plate of the present invention; Figure 5 is a schematic structural diagram of a foot fastener of the present invention; Figure 6 It is a schematic diagram of the cross-sectional structure of the telescopic sliding column of the present invention.

[0019] In the figure: 1, support frame; 11, connecting slide; 2, power mechanism; 21, connecting column; 22, rotating column; 23, scroll spring; 24, rotating rod; 25, support plate; 26, sponge pad 1; 27, limit mechanism; 271, sliding column; 272, tightening spring; 273, U-shaped rotating frame; 274, annular rotating plate; 275, limit stop column; 276, positioning column; 3, sliding seat plate; 31, support plate; 32, connecting slide Plate; 33, sliding wheel; 34, knob one; 35, bidirectional screw; 36, threaded slider; 37, push rod; 38, sliding push plate; 39, fixed pressure plate; 4, sliding pedal; 5, foot holder; 51, connecting sleeve; 52, telescopic sliding column; 521, lifting column; 522, knob two; 523, transmission screw; 524, square column; 525, limit slide groove; 526, limit slider; 53, connecting rod; 54, sponge pad two. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with embodiments: Example

[0021] like Figure 1-3As shown, the present invention provides a power assisting mechanism of fitness equipment, including a support frame 1, a power assisting mechanism 2 is fixedly installed on the top rear side of the support frame 1, a sliding seat plate 3 is slidably connected to the rear side of the inner surface of the support frame 1, a sliding pedal 4 is slidably connected to the front side of the inner surface of the support frame 1, the sliding pedal 4 and the sliding seat plate 3 adopt the same structure, a foot fixer 5 is fixedly installed on the top of the sliding pedal 4, and connecting slide grooves 11 are provided on the left and right sides of the inner wall of the support frame 1. The power assisting mechanism 2 includes two connecting columns 21, and the two connecting columns 21 are respectively fixedly connected to the left and right rear sides of the top of the support frame 1, a rotating groove is provided on the top of the connecting column 21, and a rotating column 22 is rotatably connected inside the rotating groove, and a spiral spring 23 is fixedly connected to the middle part of the opposite surface of the two rotating columns 22, and one end of the spiral spring 23 away from the rotating column 22 is fixedly connected to the inner wall of the rotating groove, and a rotating rod 24 is fixedly connected to the rear side of the top of the outer surface of the two rotating columns 22, and the rear ends of the two rotating rods 24 are fixedly connected to a support plate 25. A sponge pad 26 is fixedly connected to the middle part of the outer surface of the support plate 25, and a limiting mechanism 27 is arranged on the inner wall of the rotating groove. The limiting mechanism 27 comprises a sliding column 271, and two sliding columns 271 are movably connected to the opposite sides of the two connecting columns 21 respectively. A movable groove is provided inside the connecting column 21, and one end of the sliding column 271 close to the connecting column 21 penetrates into the inside of the movable groove and is fixedly connected with a tightening spring 272, and one end of the sliding column 271 close to the tightening spring 272 is fixedly connected with a U-shaped rotating frame 273, both ends of the U-shaped rotating frame 273 penetrate into the inside of the rotating groove and are fixedly connected with an annular rotating plate 274, and a limited stopper column 275 is fixedly connected to the front of the side of the annular rotating plate 274 away from the U-shaped rotating frame 273, and a positioning column 276 is fixedly connected to the front and rear sides of the side of the U-shaped rotating frame 273 away from the annular rotating plate 274, and a plurality of positioning grooves are provided in a circular array on the inner wall of the movable groove, and one end of the positioning column 276 away from the U-shaped rotating frame 273 penetrates into the inside of the positioning groove.

[0022] In this embodiment, when the user performs sit-ups, he / she sits on the sliding seat plate 3. When the user lies down, the sponge pad 26 on the support plate 25 is squeezed, and the rotating column 22 drives the spiral spring 23 to contract through the rotating rod 24. Therefore, when the user sits up, the elastic force of the spiral spring 23 can enable the rotating rod 24 to provide a pushing force to the user's back through the support plate 25 and the sponge pad 26, making it more convenient for the user to perform sit-ups. By pressing the sliding column 271, the U-shaped rotating frame 273 can be driven to move. The movable positioning column 276 slides out from the interior of the positioning groove, so that the U-shaped rotating frame 273 and the sliding column 271 are no longer restricted, which makes it convenient to drive the U-shaped rotating frame 273 to rotate through the sliding column 271, and the limiting stop column 275 can be driven to rotate through the annular rotating plate 274. After that, the positioning column 276 can be stuck into the interior of another positioning groove through the pushing of the tightening spring 272, and the position of the limiting stop column 275 can be fixed, so that the position pushed by the support plate 25 and the sponge pad 26 can be limited, making the sit-up training more scientific, comfortable and efficient. Example

[0023] like Figure 4 As shown, on the basis of Example 1, the present invention provides a technical solution: preferably, the sliding seat plate 3 includes a support plate 31, and the left and right sides of the support plate 31 are fixedly connected with a connecting slide plate 32, the connecting slide plate 32 is slidably connected to the inside of the connecting slide groove 11, and the front and rear sides of the inside of the connecting slide plate 32 are movably connected with sliding wheels 33 that penetrate up and down, and the rear end of the support plate 31 is movably connected with a knob 34, and the front end of the knob 34 is fixedly connected with a bidirectional screw 35, and the bidirectional screw 35 is movably connected to the bottom of the support plate 31, and the outer surface of the bidirectional screw 35 is threadedly connected with screws on the front and rear sides. A threaded slider 36, the upper surface of which is slidably connected to the lower surface of the support plate 31, and push rods 37 are movably connected to the left and right sides of the threaded slider 36. One end of the two push rods 37 on the same side of the left and right sides away from the threaded slider 36 is movably connected to a sliding push plate 38, and a sliding groove is provided in the middle of the side of the connecting slide plate 32 away from the support plate 31, and the sliding push plate 38 is slidably connected to the lower surface of the support plate 31, and one end of the sliding push plate 38 away from the support plate 31 penetrates into the interior of the sliding groove and is fixedly connected to a fixed pressing plate 39, and the outer surface of the fixed pressing plate 39 is slidably connected to the inner surface of the sliding groove.

[0024] In this embodiment, the position of the sliding seat plate 3 can be adjusted by sliding the connecting slide plate 32 and the sliding wheel 33 in the connecting slide groove 11, which is convenient for users of different heights to use. At the same time, by rotating the knob 34, the bidirectional screw 35 can drive the threaded slider 36 to slide on the bottom of the support plate 31, so that the sliding push plate 38 can be pushed to slide on the bottom of the support plate 31 by the push rod 37, so that the fixed pressure plate 39 can be pushed and the inner wall of the connecting slide groove 11 can be pressed, so that the position of the sliding seat plate 3 can be fixed, making the use of the sit-up power assist mechanism more convenient. Example

[0025] like Figure 5-6 As shown, on the basis of Example 1, the present invention provides a technical solution: preferably, the foot fixer 5 includes a connecting sleeve 51, the connecting sleeve 51 is fixedly connected to the top of the support frame 1, and a telescopic sliding column 52 is slidably inserted at the top of the inner surface of the connecting sleeve 51, and the left and right sides of the outer surfaces of the connecting sleeve 51 and the telescopic sliding column 52 are fixedly connected with connecting rods 53, and the outer surface of the connecting rod 53 is fixedly connected with a sponge pad 2 54, and the telescopic sliding column 52 includes a lifting column 521, and the lifting column 521 is slidably inserted above the inner surface of the connecting sleeve 51, and the top of the lifting column 521 is movably connected with a knob 2 522, and the knob 2 522 is movably connected to the top of the lifting column 521. A transmission screw 523 is fixedly connected to the bottom of button 2 522, and a square slide groove is provided at the bottom end of the lifting column 521. The bottom end of the transmission screw 523 penetrates into the interior of the square slide groove and the outer surface is threadedly connected with a square column 524. The outer surface of the square column 524 is slidably connected to the inner surface of the square slide groove, and the bottom end of the square column 524 is fixedly connected to the lower surface of the inner wall of the connecting sleeve 51. Limiting slide grooves 525 are provided on the front and rear sides of the outer surface of the square column 524. Limiting sliders 526 are fixedly connected to the lower front and rear sides of the inner wall of the square slide groove, and the limiting slider 526 is slidably connected to the inside of the limiting slide groove 525.

[0026] In this embodiment, the user can fix his feet between the connecting rod 53 and the second sponge pad 54 while doing sit-ups, making the sit-up training more comfortable. At the same time, by rotating the second knob 522, the transmission screw 523 can be driven to rotate, thereby driving the lifting column 521 to be lifted and lowered along the square column 524 through threaded transmission with the square column 524, so that the positions of the top connecting rod 53 and the second sponge pad 54 can be adjusted, and the lifting range of the lifting column 521 can be limited by the sliding of the limiting slider 526 in the limiting slide groove 525, which is convenient for different users to use and facilitates different users to perform sit-up training.

[0027] The following is a detailed description of the working principle of the power assistance mechanism of this fitness equipment.

[0028] like Figure 1-6 As shown, when the user does sit-ups, he sits on the sliding seat plate 3, and the position of the sliding seat plate 3 can be adjusted by sliding the connecting slide plate 32 and the sliding wheel 33 in the connecting slide groove 11, which is convenient for users of different heights to use. At the same time, by rotating the knob 1 34, the bidirectional screw 35 can drive the threaded slider 36 to slide, so that the sliding push plate 38 can be pushed to slide by the push rod 37, so that the fixed pressure plate 39 can press the inner wall of the connecting slide groove 11, so that the position of the sliding seat plate 3 can be fixed. After that, the user can place his feet between the two sponge pads 2 54, and by rotating the knob 2 522, the user can The threaded transmission of the transmission screw 523 and the square column 524 can drive the lifting column 521 to move up and down and slide, so that the position of the top sponge pad 2 54 can be adjusted, which is convenient for different users. When the user lies down, the sponge pad 1 26 on the support plate 25 will be squeezed, and the rotating column 22 can drive the spiral spring 23 to contract through the rotating rod 24. When the user sits up, the elastic force of the spiral spring 23 can enable the rotating rod 24 to provide a pushing force to the user's back through the support plate 25 and the sponge pad 1 26, making it more convenient for the user to perform sit-up training, and making the sit-up training more scientific, comfortable and efficient.

[0029] The above generally describes the present invention in detail, but it is obvious to a person skilled in the art that some modifications or improvements can be made to the present invention. Therefore, modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A power assist mechanism of a fitness equipment, characterized in that: The invention comprises a support frame (1), a power-assisting mechanism (2) is fixedly mounted on the rear side of the top of the support frame (1), a sliding seat plate (3) is slidably connected to the rear side of the inner surface of the support frame (1), a sliding pedal (4) is slidably connected to the front side of the inner surface of the support frame (1), a foot holder (5) is fixedly mounted on the top of the sliding pedal (4), and connecting slide grooves (11) are provided on both left and right sides of the inner wall of the support frame (1); The power-assisting mechanism (2) comprises two connecting columns (21), the two connecting columns (21) are respectively fixedly connected to the left and right rear sides of the top of the support frame (1), a rotating groove is provided at the top of the connecting column (21), a rotating column (22) is rotatably connected inside the rotating groove, a volute spring (23) is fixedly connected to the middle of the opposite surfaces of the two rotating columns (22), one end of the volute spring (23) away from the rotating column (22) is fixedly connected to the inner wall of the rotating groove, a rotating rod (24) is fixedly connected to the rear side of the top of the outer surface of the two rotating columns (22), a supporting plate (25) is fixedly connected to the rear end of the two rotating rods (24), a sponge pad (26) is fixedly connected to the middle of the outer surface of the support plate (25), and a limiting mechanism (27) is provided on the inner wall of the rotating groove; The foot holder (5) comprises a connecting sleeve (51), the connecting sleeve (51) being fixedly connected to the top of the support frame (1), a telescopic sliding column (52) being slidably inserted at the top of the inner surface of the connecting sleeve (51), connecting rods (53) being fixedly connected to the left and right sides of the outer surfaces of the connecting sleeve (51) and the telescopic sliding column (52), and a second sponge pad (54) being fixedly connected to the outer surface of the connecting rod (53).

2. The power assist mechanism of the fitness equipment according to claim 1, characterized in that: The limiting mechanism (27) comprises a sliding column (271), wherein two sliding columns (271) are movably connected to opposite sides of two connecting columns (21), respectively, and a movable groove is provided inside the connecting column (21), and one end of the sliding column (271) close to the connecting column (21) penetrates into the movable groove and is fixedly connected to a tightening spring (272), and one end of the sliding column (271) close to the tightening spring (272) is fixedly connected to a U-shaped rotating frame (273).

3. The power assist mechanism of the fitness equipment according to claim 2, characterized in that: Both ends of the U-shaped rotating frame (273) penetrate into the interior of the rotating groove and are fixedly connected to an annular rotating plate (274); a limited stopper column (275) is fixedly connected to the front of a side of the annular rotating plate (274) away from the U-shaped rotating frame (273); both front and rear sides of a side of the U-shaped rotating frame (273) away from the annular rotating plate (274) are fixedly connected to positioning columns (276); a plurality of positioning grooves are formed in an annular array on the inner wall of the movable groove; and one end of the positioning column (276) away from the U-shaped rotating frame (273) penetrates into the interior of the positioning groove.

4. The power assist mechanism of the fitness equipment according to claim 1, characterized in that: The sliding seat plate (3) comprises a support plate (31), the left and right sides of the support plate (31) are fixedly connected to connecting slide plates (32), the connecting slide plates (32) are slidably connected inside the connecting slide groove (11), and the front and rear sides inside the connecting slide plates (32) are movably connected to sliding wheels (33) that penetrate up and down.

5. The power assist mechanism of the fitness equipment according to claim 4, characterized in that: A knob (34) is movably connected to the lower portion of the rear end of the support plate (31); a bidirectional screw (35) is fixedly connected to the front end of the knob (34); the bidirectional screw (35) is movably connected to the bottom of the support plate (31); a threaded slider (36) is threadedly connected to the front and rear sides of the outer surface of the bidirectional screw (35); and the upper surface of the threaded slider (36) is slidably connected to the lower surface of the support plate (31).

6. The power assist mechanism of the fitness equipment according to claim 5, characterized in that: The left and right sides of the threaded slider (36) are movably connected to push rods (37), and the ends of the two push rods (37) on the same side are movably connected to a sliding push plate (38) away from the threaded slider (36). A sliding groove is provided in the middle of the side of the connecting slide plate (32) away from the support plate (31), and the sliding push plate (38) is slidably connected to the lower surface of the support plate (31). The end of the sliding push plate (38) away from the support plate (31) penetrates into the interior of the sliding groove and is fixedly connected to a fixed pressure plate (39), and the outer surface of the fixed pressure plate (39) is slidably connected to the inner surface of the sliding groove.

7. The power assist mechanism of the fitness equipment according to claim 1, characterized in that: The telescopic sliding column (52) comprises a lifting column (521), the lifting column (521) being slidably inserted above the inner surface of the connecting sleeve (51), the top of the lifting column (521) being movably connected to a second knob (522), and the bottom of the second knob (522) being fixedly connected to a transmission screw (523).

8. The power assist mechanism of the fitness equipment according to claim 7, characterized in that: A square slide groove is provided at the bottom end of the lifting column (521); the bottom end of the driving screw (523) penetrates into the interior of the square slide groove and is threadedly connected to a square column (524) on the outer surface; the outer surface of the square column (524) is slidably connected to the inner surface of the square slide groove; the bottom end of the square column (524) is fixedly connected to the lower surface of the inner wall of the connecting sleeve (51); limiting slide grooves (525) are provided on the front and rear sides of the outer surface of the square column (524); limiting sliders (526) are fixedly connected to the lower parts of the front and rear sides of the inner wall of the square slide groove; the limiting sliders (526) are slidably connected to the interior of the limiting slide grooves (525).

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