WO2025180255A1 - Adjustable leg workout machine - Google Patents

Abstract

An adjustable leg workout machine, comprising a machine frame (1), a base frame (4), a footplate (5), a footplate frame, and a seat (10), wherein the footplate frame comprises a linkage arm (2) and a fixing frame (3); the bottom end of the base frame (4) is hinged to the machine frame (1), and the top end of the base frame (4) is hinged to the front end of the linkage arm (2); the front end of the linkage arm (2) is connected to a first barbell shaft (7), the rear end of the linkage arm (2) is fixedly connected to the bottom end of the fixing frame (3), and the rear end of the linkage arm (2) is hinged to the machine frame (1); the footplate (5) is connected to the front side of the top end of the fixing frame (3), and a second barbell shaft (6) is provided on the rear side of the fixing frame (3); and the seat (10) is arranged on the machine frame (1) via a position adjustment mechanism and an angle adjustment mechanism, and the seat (10) is located on the front side of the base frame (4).

Description

An adjustable leg training machine Technical Field

The utility model relates to the technical field of fitness equipment, in particular to an adjustable leg training machine.

Background Art

The leg training machine is a common fitness equipment that is widely used in fitness environments such as gyms. It mainly trains the leg muscles by simulating the pedaling motion of the lower body, strengthening and shaping the lower body muscle groups. At the same time, leg training can effectively improve cardiovascular health and increase the explosiveness and flexibility of the legs. At present, most leg training equipment is not flexible enough and can only adjust the leg kicking distance according to the leg length of different trainees. Leg training is often done in a reclining position. In addition to the leg kicking distance, the trainee's leaning angle also affects the comfort and effect of training. At the same time, the pedal structure of the leg training equipment usually has a large deadweight. When the trainee retracts their legs, the pedal structure will be affected by the gravity of the pedal structure. For people with less strength, it is easy to not be able to support the weight of the pedal structure when retracting their legs, which will cause training difficulties or even injury to the trainee. Existing leg training equipment is difficult to meet the needs of different trainees. Therefore, there is a need for a leg training machine with high flexibility and strong adaptability.

Utility Model Content

In order to solve the problems existing in the background technology, the utility model proposes an adjustable leg training machine, including a frame, a footrest, a base frame, a footrest frame and a seat, the footrest frame including a linkage arm and a fixed frame, the bottom end of the base frame is hinged to the frame, the top end of the base frame is hinged to the front end of the linkage arm, the front end of the linkage arm is connected to the first barbell shaft, the rear end of the linkage arm is fixedly connected to the bottom end of the fixed frame, the rear end of the linkage arm is hinged to the frame, the front side of the top end of the fixed frame is connected to the footrest, and the rear side of the fixed frame is provided with a second barbell shaft, the seat is arranged on the frame through a position adjustment mechanism and an angle adjustment mechanism, and the seat is located on the front side of the base frame.

Preferably, the position adjustment mechanism includes a sliding plate and an adjustment plate, the adjustment plate is fixedly connected to the frame, a plurality of first adjustment holes are provided on the adjustment plate in the front-to-back direction, the sliding plate is slidably set on the frame, a first positioning pin matching the first adjustment hole is provided on the sliding plate, and the seat is set on the sliding plate.

Preferably, the sliding plate is provided with an adjustment handle, the first positioning latch comprises a first fixed shell, a first latch, a first return spring and a first limit rod, the first fixed shell is fixedly connected to the sliding plate, the first fixed shell is communicated with the sliding plate, the first latch is slidably arranged in the first fixed shell, the first latch is located at one end of the first fixed shell close to the sliding plate, the first limit rod is fixed in the first fixed shell, the first limit rod is located at one end of the first fixed shell away from the sliding plate, a sliding rod is provided at one end of the first latch away from the sliding plate, the sliding rod has a diameter smaller than that of the first latch and the first limit rod, the sliding rod slides through the first limit rod and extends outside the first fixed shell, and the first return spring is arranged between the first limit rod and the first latch;

One end of the adjusting handle is hinged to the sliding plate, and the other end of the adjusting handle extends to one side of the seat. One end of the sliding rod located outside the first fixed shell is connected to the adjusting handle.

Preferably, the seat includes a seat plate and a backrest, the seat plate is fixedly connected to the sliding plate, the bottom end of the backrest is hinged to the sliding plate, the angle adjustment mechanism includes an adjusting rod and an adjusting tube, one end of the adjusting tube is hinged to the top end of the backrest, and the other end of the adjusting tube is slidably sleeved on the outer wall of one end of the adjusting rod, the other end of the adjusting rod is hinged to the sliding plate, a plurality of second adjustment holes are provided on the adjusting rod along the length direction, and a second positioning pin matching the second adjustment hole is provided on the adjusting tube.

Preferably, a pin control mechanism is provided on one side of the seat plate for controlling the second positioning pin to insert/disengage from the second adjustment hole, and a first gas spring is provided on the back side of the backrest, one end of the first gas spring is hinged to the backrest, and the other end of the first gas spring is hinged to the sliding plate.

Preferably, the second positioning latch includes a second fixed shell, a second latch, a second return spring and a second limiting rod, the second fixed shell is fixedly connected to the adjustment tube, the second fixed shell is communicated with the adjustment tube, the second latch is slidably arranged in the second fixed shell, the second latch is located at an end of the second fixed shell close to the adjustment tube, the second limiting rod is fixed in the second fixed shell, the second limiting rod is located at an end of the second fixed shell away from the adjustment tube, a wiring hole is provided in the second limiting rod, and the second return spring is arranged between the second limiting rod and the second latch;

The latch control mechanism includes a brake line and a handle, the handle is hinged on one side of the seat plate, one end of the brake line is connected to the handle, and the other end of the brake line passes through the routing hole and the second return spring and is connected to the second latch.

Preferably, a second buffer block is fixed on the sliding plate, and the second buffer block is located on the backrest.

Preferably, the base frame is a U-shaped frame, and there are two linkage arms, which are respectively located on both sides of the seat, and the front ends of the two linkage arms are respectively connected to the two vertical rods of the U-shaped frame.

Preferably, it also includes an adjustment arm and an adjustment rod, the bottom end of the adjustment arm is hinged to the front end of the linkage arm, the top end of the adjustment arm is fixed to the first barbell shaft, one end of the adjustment rod is hinged to the adjustment arm, and the other end of the adjustment rod is hinged to the frame.

Preferably, an adjustable safety mechanism is provided on the frame, and the adjustable safety mechanism is located below the linkage arm. The adjustable safety mechanism includes an adjusting handle, a fixed tube and a moving rod. The fixed tube is fixed on the frame, and the moving rod is slidably set in the fixed tube, and both ends of the moving rod extend outside the fixed tube. A plurality of third adjustment holes are provided on the moving rod along the length direction, and a third positioning pin matching the third adjustment hole is provided on the fixed tube. A first buffer block is provided at the top end of the moving rod, and the adjusting handle is fixed at the bottom end of the moving rod.

The utility model has the following beneficial effects:

The utility model has a seat with adjustable position and backrest angle, and the seat can be adjusted according to the height, leg length, etc. of the trainee. The seat is flexible to use and more ergonomic, and can meet the needs of different trainees, thereby improving the training effect and comfort.

The utility model can alleviate the problem of the deadweight of the pedal part by increasing or decreasing the weight of the barbell plates on the second barbell shaft. That is, when the trainee retracts his legs and the pedal structure returns to the state where it begins to fall under its own weight, the barbell plates on the second barbell shaft can exert a force on the pedal structure that is opposite to the gravity of the pedal structure, avoiding the situation where the trainee cannot support the pedal plate when retracting his legs due to the excessive weight of the pedal structure, thereby improving the training effect and training safety. At the same time, the weight of the barbell plates on the second barbell shaft can be adjusted according to the strength of different training, thereby meeting the usage needs of different trainees.

3. Since the trainee's legs are bent in the initial state of training, it is most strenuous to push up at this time. As the legs continue to straighten, the trainee will feel relaxed. Therefore, it will be difficult to push up smoothly when the load is heavy, and the training effect cannot be achieved when the load is light. The utility model is provided with an adjustment arm and an adjustment pull rod, which can realize the change of the force arm during pedaling training. As the trainee's legs extend when pedaling, the adjustment pull rod drives the adjustment arm to swing backward, so that the force arm from the barbell plate on the first barbell axis to the hinge point becomes longer, and the force required for the trainee to push the pedal plate increases, so that the trainee can push up smoothly while ensuring good training effect.

4. The utility model is provided with an adjustable safety mechanism to prevent the linking arm from falling due to mistakes during training, thereby improving the safety of training.

5. The utility model is provided with a latch control mechanism, which enables the trainee to adjust the backrest angle on the seat. The adjustment is convenient and the trainee can feel whether the backrest angle is appropriate in real time. At the same time, the first gas spring can support the backrest when adjusting the angle, preventing the trainee from falling down instantly, thereby improving the reliability of the adjustment.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram of the overall structure of the utility model;

Figure 2 is a schematic diagram of the side structure of the utility model;

Figure 3 is a schematic diagram of the structure of the present invention after the sliding plate is hidden;

Figure 4 is an enlarged view of point A in Figure 3;

Figure 5 is a cross-sectional view of the first positioning latch structure of the present invention;

FIG6 is a cross-sectional view of the second positioning latch structure of the present invention.

Reference numerals in the figure: 1, frame; 2, linkage arm; 3, fixed frame; 4, bottom frame; 5, footrest; 51, gripper; 6, second barbell shaft; 7, first barbell shaft; 8, adjustment arm; 9, adjustment rod; 10, seat; 101, seat plate; 102, backrest; 11, sliding plate; 12, first positioning pin; 121, first fixed shell; 122, first pin; 123, first limiting rod; 124, sliding rod; 125, first return spring; 13, adjustment tube; 14, adjustment rod; 141, second adjustment hole; 15, second positioning pin; 151, second fixed shell; 152. Second limit rod; 153. Second return spring; 154. Second latch; 16. Brake line; 17. Adjustable safety mechanism; 171. Moving rod; 172. Adjusting handle; 173. First buffer block; 174. Fixed tube; 8. Sliding sleeve; 19. Sliding shaft; 20. First gas spring; 21. Adjusting handle; 22. Second buffer block; 23. Foot pedal; 24. Foot pedal frame cover; 25. Power lever; 26. Seat armrest; 27. Adjusting plate; 271. First adjusting hole; 28. Handle; 29. Second gas spring; 30. Connecting rod; 31. Rear barbell axle frame.

DETAILED DESCRIPTION

In order to make the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the given embodiment is only one implementation method and does not represent all embodiments.

In this article, terms such as "upper, lower, front, and back" are established based on the positional relationships shown in the drawings. Depending on the different drawings, the corresponding positional relationships may also change accordingly. Therefore, they cannot be understood as absolute limitations on the scope of protection.

In conjunction with Figures 1-6, an adjustable leg training machine includes a frame 1, a footrest 5, a base frame 4, a footrest frame and a seat 10, the footrest frame includes a linkage arm 2 and a fixed frame 3, the bottom end of the base frame 4 is hinged to the frame 1, the top end of the base frame 4 is hinged to the front end of the linkage arm 2, the front end of the linkage arm 2 is connected to a first barbell shaft 7, the rear end of the linkage arm 2 is fixedly connected to the bottom end of the fixed frame 3, the rear end of the linkage arm 2 is hinged to the frame 1, the position of the rear end of the linkage arm 2 is higher than the position of the front end of the linkage arm 2, the front side of the top end of the fixed frame 3 is connected to the footrest 5, and the rear side of the fixed frame 3 is provided with a second barbell shaft 6, the second barbell shaft 6 is connected to the fixed frame 3 through a rear barbell shaft frame 31, the seat 10 is arranged on the frame 1 through a position adjustment mechanism and an angle adjustment mechanism, and the seat 10 is located on the front side of the base frame 4. More specifically, the footrest 5 is connected to the fixed frame 3 via a footrest frame cover 24. The footrest 5 is fixed to the front end of the footrest frame cover 24. A power-assisting rod 25 is provided at the rear end of the footrest frame cover 24. The top end of the power-assisting rod 25 is hinged to the rear end of the footrest frame cover 24, and the bottom end of the power-assisting rod 25 is hinged to the frame 1. The fixed frame 3 is hinged to the middle and rear position of the footrest frame cover 24. A footrest 23 is fixed to the frame 1 in front of the seat 10. The first barbell shaft 7 and the second barbell shaft 6 are used to place barbell plates. A grip 51 is provided at the top end of the footrest 5.

Specifically, the position adjustment mechanism includes a sliding plate 11 and an adjustment plate 27. The adjustment plate 27 is fixedly connected to the frame 1. The adjustment plate 27 is provided with a plurality of first adjustment holes 271 in the front-to-back direction. The sliding plate 11 is slidably mounted on the frame 1. The sliding plate 11 is provided with a first positioning pin 12 that matches the first adjustment holes 271. The seat 10 is mounted on the sliding plate 11. When the first positioning pin 12 is disengaged from the first adjustment hole 271, the sliding plate 11 can slide. By moving the sliding plate 11, the first positioning pin 12 is aligned with a different first adjustment hole 271. The sliding plate 11 is fixed by inserting the first positioning pin 12 into the first adjustment hole 271, thereby adjusting the position of the seat 10. More specifically, a second gas spring 29 is provided at the front of the sliding plate 11. One end of the second gas spring 29 is connected to the sliding plate 11, and the other end of the second gas spring 29 is connected to the frame 1. The second gas spring 29 can provide a booster, improving the reliability of position adjustment.

Specifically, a sliding shaft 19 is fixed on the frame 1. There are two sliding shafts 19 and they are distributed on both sides of the frame 1. A sliding sleeve 8 is slidingly provided on the sliding shaft 19. A buffer pad is provided at the end of the sliding shaft 19. The buffer pad can prevent the sliding sleeve 8 from bumping, etc. The length of the sliding sleeve 8 is smaller than the length of the sliding shaft 19. The two ends of the sliding plate 11 are respectively fixedly connected to the two sliding sleeves 8. The sliding plate 11 can slide along the sliding shaft 19 through the sliding sleeve 8. The sliding plate 11 is located above the adjustment plate 27.

Specifically, the sliding plate 11 is provided with an adjusting handle 21, the first positioning latch 12 includes a first fixed shell 121, a first latch 122, a first return spring 125 and a first limit rod 123, the first fixed shell 121 is fixedly connected to the sliding plate 11, the first fixed shell 121 is communicated with the sliding plate 11, the first latch 122 is slidably arranged in the first fixed shell 121, the first latch 122 is located at one end of the first fixed shell 121 close to the sliding plate 11, the first limit rod 123 is fixed in the first fixed shell 121, the first limit rod 123 is located at one end of the first fixed shell 121 away from the sliding plate 11, and a sliding rod 124 is provided at the end of the first latch 122 away from the sliding plate 11, the sliding rod 124 has a diameter smaller than that of the first latch 122 and the first limit rod 123, the sliding rod 124 slides through the first limit rod 123 and extends outside the first fixed shell 121, and the first return spring 125 is arranged between the first limit rod 123 and the first latch 122;

One end of the adjustment handle 21 is hinged to the sliding plate 11, and the other end of the adjustment handle 21 extends to one side of the seat 10. The end of the sliding rod 124 located outside the first fixed shell 121 is connected to the adjustment handle 21. When the position of the seat 10 needs to be adjusted, the trainer only needs to lift the end of the adjustment handle 21 located on the side of the seat 10. When the adjustment handle 21 is lifted, the first latch 122 is pulled upward, and the first latch 122 disengages from the first adjustment hole 271. The first return spring 125 is compressed, and the sliding plate 11 can now slide. After moving the sliding plate 11 to the appropriate position, the trainer releases the adjustment handle 21, and the first return spring 125 loses its compression effect and returns to its original position. The first return spring 125 drives the first latch 122 downward, and the first latch 122 is inserted into the first adjustment hole 271, fixing the sliding plate 11. The method of adjusting the position of the seat 10 is simple and convenient, and the trainer can complete the adjustment on the seat 10.

Specifically, the chair 10 includes a seat plate 101 and a backrest 102, the seat plate 101 is fixedly connected to the sliding plate 11, and seat armrests 26 are provided on both sides of the seat plate 101. The trainee can hold the seat armrests for support during training, and the bottom end of the backrest 102 is hinged to the sliding plate 11. The angle adjustment mechanism includes an adjusting rod 14 and an adjusting tube 13, one end of the adjusting tube 13 is hinged to the top of the backrest 102, and the other end of the adjusting tube 13 is slidably sleeved on the outer wall of one end of the adjusting rod 14, and the other end of the adjusting rod 14 is hinged to the sliding plate 11. A plurality of second adjustment holes 141 are provided on the adjusting rod 14 along the length direction, and a second positioning pin 15 matching the second adjustment hole 141 is provided on the adjusting tube 13. When the second positioning pin 15 is disengaged from the second adjustment hole 141 , the adjustment tube 13 can slide along the adjustment rod 14 , driving the backrest 102 to rotate, thereby adjusting the angle of the backrest 102 ; inserting the second positioning pin 15 into the second adjustment hole 141 can fix the adjustment tube 13 , thereby fixing the backrest 102 .

Specifically, one side of the seat plate 101 is provided with a pin control mechanism for controlling the second positioning pin 15 to insert/disengage from the second adjustment hole 141, and the rear side of the backrest 102 is provided with a first gas spring 20. One end of the first gas spring 20 is hinged to the backrest 102, and the other end of the first gas spring 20 is hinged to the sliding plate 11. The first gas spring 20 can support the backrest 102 when adjusting the angle, thereby preventing the trainee from falling down instantly and improving the reliability of the adjustment.

Specifically, the second positioning latch 15 includes a second fixed shell 151, a second latch 154, a second return spring 153 and a second limiting rod 152. The second fixed shell 151 is fixedly connected to the adjustment tube 13, and the second fixed shell 151 is in communication with the adjustment tube 13. The second latch 154 is slidably arranged in the second fixed shell 151. The second latch 154 is located at an end of the second fixed shell 151 close to the adjustment tube 13. The second limiting rod 152 is fixed in the second fixed shell 151. The second limiting rod 152 is located at an end of the second fixed shell 151 away from the adjustment tube 13. A wiring hole is provided in the second limiting rod 152. The second return spring 153 is arranged between the second limiting rod 152 and the second latch 154.

The latch control mechanism includes a brake cable 16 and a handle 28. The handle 28 is hinged to one side of the seat plate 101. One end of the brake cable 16 is connected to the handle 28, and the other end of the brake cable 16 passes through the wiring hole and the second return spring 153 and is connected to the second latch 154. When the angle of the backrest 102 needs to be adjusted, the trainer only needs to lift the handle 28 and pull the brake cable 16 through the handle 28. The brake cable 16 pulls the second latch 154, and the second latch 154 disengages from the second adjustment hole 141. The second return spring 153 is compressed, and the adjustment tube 13 can now slide. After adjusting the backrest 102 to the appropriate angle, the trainer releases the handle 28, and the second return spring 153 loses its compression effect and returns to its original position. The second return spring 153 drives the second latch 154 to move, so that the second latch 154 is inserted into the second adjustment hole 141, fixing the adjustment tube 13 and thus fixing the backrest 102. The latch control mechanism allows the trainee to adjust the angle of the backrest 102 while on the chair 10, making it easy and convenient to use. More specifically, a plurality of cable routing tubes are provided on the rear side of the backrest 102 to restrict the routing path of the brake cable 16, thereby ensuring a neat arrangement of the brake cable 16 and preventing it from being caught by foreign objects.

Specifically, a second buffer block 22 is fixed on the sliding plate 11 . The second buffer block 22 is located at the rear side of the backrest 102 . The second buffer block 22 can protect the backrest 102 .

Specifically, the base frame 4 is a U-shaped frame, and the linkage arms 2 are two, and the two linkage arms 2 are respectively located on both sides of the seat 10. The front ends of the two linkage arms 2 are respectively connected to the two vertical rods of the U-shaped frame. The front side of the bottom end of the base frame 4 is provided with a linkage rod 30 and a reset handle. The reset handle is hinged to the frame 1. One end of the linkage rod 30 is hinged to the base frame 4, and the other end of the linkage rod 30 is hinged to the reset handle. The hinge point between the linkage rod 30 and the reset handle is located below the hinge point between the frame 1 and the reset handle. The frame 1 is also fixed with a third buffer block and a fourth buffer block. The third buffer block is located at the front side of the bottom end of the base frame 4, and the fourth buffer block is located at the rear side of the top of the base frame 4. The two buffer blocks play a protective and supporting role for the base frame 4. The trainee can rotate the base frame 4 by swinging the reset handle to adjust the state of the training machine. Specifically, before training, the reset handle is pushed forward so that the base frame 4 rests on the fourth buffer block at its rear side. After stopping training, the reset handle is pulled back.

Specifically, it also includes an adjustment arm 8 and an adjustment rod 9. The bottom end of the adjustment arm 8 is hinged to the front end of the linkage arm 2. The top end of the adjustment arm 8 is fixed to the first barbell shaft 7. One end of the adjustment rod 9 is hinged to the adjustment arm 8, and the other end of the adjustment rod 9 is hinged to the frame 1. The adjustment arm 8 and the adjustment rod 9 can realize the change of the force arm during the training process, and can increase the training weight as the trainee's legs stretch. While ensuring that the trainee can push up smoothly, the training weight meets the training requirements. More specifically, a safety hook is provided at the front end of the linkage arm 2. When the adjustment arm 8 falls off due to reasons such as the screw falling off, the safety hook can block the adjustment arm 8 and prevent the adjustment arm 8 from falling toward the seat 10, thereby preventing the adjustment arm 8 from hitting the trainee and providing safety protection for the user.

Specifically, the frame 1 is provided with an adjustable safety mechanism 17, which is located below the linkage arm 2. The adjustable safety mechanism 17 includes an adjustment handle 172, a fixed tube 174, and a movable rod 171. The fixed tube 174 is fixed to the frame 1. The movable rod 171 is slidably arranged in the fixed tube 174, and both ends of the movable rod 171 extend outside the fixed tube 174. The movable rod 171 is provided with a plurality of third adjustment holes along its length. The fixed tube 174 is provided with a third positioning pin that matches the third adjustment holes. The top of the movable rod 171 is provided with a first buffer block 173, and the adjustment handle 172 is fixed to the bottom of the movable rod 171. The adjustable safety mechanism 17 can prevent the linkage arm 2 from falling due to mistakes during training, thereby improving the safety of training.

The above describes the specific embodiments of the present invention in detail with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. It is clear to those skilled in the art that various changes, modifications, substitutions, and variations to these embodiments may be made without departing from the principles and spirit of the present invention, and these changes and modifications still fall within the scope of protection of the present invention.

Claims (10)

An adjustable leg training machine, characterized in that it includes a frame (1), a base frame (4), a pedal board (5), a pedal board frame and a seat (10), wherein the pedal board frame includes a linkage arm (2) and a fixed frame (3), the bottom end of the base frame (4) is hinged to the frame (1), the top end of the base frame (4) is hinged to the front end of the linkage arm (2), the front end of the linkage arm (2) is connected to a first barbell shaft (7), the rear end of the linkage arm (2) is fixedly connected to the bottom end of the fixed frame (3), the rear end of the linkage arm (2) is hinged to the frame (1), the front side of the top end of the fixed frame (3) is connected to the pedal board (5), and the rear side of the fixed frame (3) is provided with a second barbell shaft (6), the seat (10) is provided on the frame (1) through a position adjustment mechanism and an angle adjustment mechanism, and the seat (10) is located on the front side of the base frame (4). An adjustable leg training machine according to claim 1, characterized in that: the position adjustment mechanism includes a sliding plate (11) and an adjustment plate (27), the adjustment plate (27) is fixedly connected to the frame (1), and a plurality of first adjustment holes (271) are provided on the adjustment plate (27) along the front-to-back direction, the sliding plate (11) is slidably set on the frame (1), and a first positioning pin (12) matching the first adjustment hole (271) is provided on the sliding plate (11), and the seat (10) is set on the sliding plate (11). An adjustable leg training machine according to claim 2, characterized in that: an adjustment handle (21) is provided on the sliding plate (11), the first positioning pin (12) includes a first fixed shell (121), a first pin (122), a first return spring (125) and a first limit rod (123), the first fixed shell (121) is fixedly connected to the sliding plate (11), the first fixed shell (121) is connected to the sliding plate (11), the first pin (122) is slidably set in the first fixed shell (121), and the first pin (122) is located at the first fixed shell (121) close to the sliding plate (11). One end, the first limiting rod (123) is fixed in the first fixed shell (121), the first limiting rod (123) is located at the end of the first fixed shell (121) away from the sliding plate (11), the end of the first latch (122) away from the sliding plate (11) is provided with a sliding rod (124), the diameter of the sliding rod (124) is smaller than the diameters of the first latch (122) and the first limiting rod (123), the sliding rod (124) slides through the first limiting rod (123) and extends to the outside of the first fixed shell (121), and the first return spring (125) is provided between the first limiting rod (123) and the first latch (122); One end of the adjustment handle (21) is hinged to the sliding plate (11), and the other end of the adjustment handle (21) extends to one side of the seat (10). One end of the sliding rod (124) located outside the first fixed shell (121) is connected to the adjustment handle (21). An adjustable leg training machine according to claim 2, characterized in that: the seat (10) includes a seat plate (101) and a backrest (102), the seat plate (101) is fixedly connected to the sliding plate (11), the bottom end of the backrest (102) is hinged to the sliding plate (11), the angle adjustment mechanism includes an adjustment rod (14) and an adjustment tube (13), one end of the adjustment tube (13) is hinged to the top end of the backrest (102), the other end of the adjustment tube (13) is slidably mounted on the outer wall of one end of the adjustment rod (14), the other end of the adjustment rod (14) is hinged to the sliding plate (11), a plurality of second adjustment holes (141) are provided on the adjustment rod (14) along the length direction, and a second positioning pin (15) matching the second adjustment hole (141) is provided on the adjustment tube (13). An adjustable leg training machine according to claim 4, characterized in that: a pin control mechanism for controlling the insertion/disengagement of the second positioning pin (15) into/from the second adjustment hole (141) is provided on one side of the seat plate (101). An adjustable leg training machine according to claim 5, characterized in that: the second positioning pin (15) includes a second fixed shell (151), a second pin (154), a second return spring (153) and a second limit rod (152), the second fixed shell (151) is fixedly connected to the adjustment tube (13), the second fixed shell (151) is communicated with the adjustment tube (13), the second pin (154) is slidably set in the second fixed shell (151), the second pin (154) is located at one end of the second fixed shell (151) close to the adjustment tube (13), the second limit rod (152) is fixed in the second fixed shell (151), the second limit rod (152) is located at one end of the second fixed shell (151) away from the adjustment tube (13), a wiring hole is provided in the second limit rod (152), and the second return spring (153) is set between the second limit rod (152) and the second pin (154); The latch control mechanism includes a brake line (16) and a handle (28), wherein the handle (28) is hinged to one side of the seat plate (101), one end of the brake line (16) is connected to the handle (28), and the other end of the brake line (16) passes through the routing hole and the second return spring (153) and is connected to the second latch (154). An adjustable leg training machine according to claim 4, characterized in that a second buffer block (22) is fixed on the sliding plate (11), and the second buffer block (22) is located on the rear side of the backrest (102). An adjustable leg training machine according to claim 1, characterized in that: the base frame (4) is a U-shaped frame, there are two connecting arms (2), the two connecting arms (2) are respectively located on both sides of the seat (10), and the front ends of the two connecting arms (2) are respectively connected to the two vertical rods of the U-shaped frame. An adjustable leg training machine according to claim 1 or 7, characterized in that it also includes an adjusting arm (8) and an adjusting rod (9), the bottom end of the adjusting arm (8) is hinged to the front end of the linkage arm (2), the top end of the adjusting arm (8) is fixed to the first barbell shaft (7), one end of the adjusting rod (9) is hinged to the adjusting arm (8), and the other end of the adjusting rod (9) is hinged to the frame (1). An adjustable leg training machine according to claim 1 or 7, characterized in that: an adjustable safety mechanism (17) is provided on the frame (1), the adjustable safety mechanism (17) is located below the linkage arm (2), the adjustable safety mechanism (17) includes an adjustment handle (172), a fixed tube (174) and a movable rod (171), the fixed tube (174) is fixed on the frame (1), the movable rod (171) is slidably set in the fixed tube (174), and both ends of the movable rod (171) extend outside the fixed tube (174), a plurality of third adjustment holes are provided on the movable rod (171) along the length direction, a third positioning pin matching the third adjustment hole is provided on the fixed tube (174), a first buffer block (173) is provided at the top end of the movable rod (171), and the adjustment handle (172) is fixed at the bottom end of the movable rod (171).