A knee joint range of motion trainer that combines angle sensing and biofeedback

Abstract

This invention discloses a knee joint range of motion trainer combining angle sensing and biofeedback, belonging to the field of rehabilitation assistive device technology. The trainer includes a hinged support frame and a lower leg frame. The support frame consists of a base and a nested thigh frame, with height adjustable via threaded pins and positioning holes. The lower leg frame includes a telescopic frame and a swing frame to accommodate different lower leg lengths. The telescopic frame is equipped with a pedal and a fixing strap for securing the lower leg. The hinge axis features an angle slot, a limiting pin, and a linkage structure of an active rod, a driven rod, and a slider. An angle sensor is installed at the left end of the hinge axis and electrically connected to an embedded calculation and control module. A detachable electric push rod is also provided. This invention allows for flexible switching of training modes, precise monitoring of knee joint range of motion angle and speed, and provides tactile feedback to indicate when the angle has reached the target, adapting to different rehabilitation stages and patient body types.

Description

Technical Field

[0001] This invention belongs to the field of rehabilitation assistive device technology, specifically relating to a knee joint range of motion trainer that combines angle sensing and biofeedback. Background Technology

[0002] Limited range of motion in the knee joint is a common problem in the rehabilitation process of patients after orthopedic surgery (such as meniscus repair, anterior cruciate ligament reconstruction), stroke sequelae, and knee degenerative diseases. The quality of rehabilitation training directly affects the recovery of limb function.

[0003] Traditional training relies heavily on manual guidance from rehabilitation therapists, which suffers from inaccurate angle monitoring, delayed patient feedback on force exertion, and difficulty in quantifying and tracking training effects, resulting in low training efficiency and potentially causing secondary injuries due to improper movements. Existing knee joint rehabilitation training equipment often lacks effective monitoring of knee joint movement speed, as some devices only have a single mechanical limiting function and poor angle adjustment flexibility. Some electronic monitoring devices have complex structures and fixed electric assistive mechanisms, making it impossible to flexibly select active or passive training modes according to the patient's rehabilitation stage. Furthermore, existing equipment lacks biofeedback, and some devices offer only simple biofeedback methods, relying solely on visual cues to provide angle information, which is ineffective for patients with poor vision or difficulty concentrating during training. Summary of the Invention

[0004] To address the technical problems of existing knee joint rehabilitation training devices, such as inaccurate angle monitoring, unclear movement speed, unintuitive angle limit feedback, and poor adaptability of electric assist mechanisms, this invention provides a knee joint range of motion trainer that combines angle sensing and biofeedback. Through the coordinated design of mechanical limit and electronic sensing, it achieves accurate monitoring of knee joint movement angle and speed, guides patient training with a biofeedback mechanism, and has the function of switching between electric assist and manual training modes to adapt to the needs of patients at different stages of rehabilitation.

[0005] To achieve the above technical objectives, the present invention is implemented through the following technical solution: a knee joint range of motion trainer combining angle sensing and biofeedback, comprising a support frame and a lower leg frame. The support frame is composed of a base and a thigh frame nested together, with several vertically arranged positioning holes on the base. Threaded pins that fit into the positioning holes are installed on the thigh frame, allowing adjustment of the overall height of the support frame by engaging the threaded pins with different positioning holes. The thigh frame is inverted L-shaped, with a soft pad at the top of its horizontal section. A lower leg frame is hinged to the front of the horizontal section of the thigh frame. The lower leg frame is composed of a telescopic frame and a swing frame nested together, and its length is adjusted in the same manner as the support frame. The swing frame is hinged to the thigh frame, and a hinge seat is provided on the lower side of the swing frame. The hinge seat is hinged to an electric push rod, the other end of which is hinged to the inner side of the vertical section of the thigh frame. The electric push rod controls the active swing of the lower leg frame, thereby assisting in knee joint range of motion training. The hinge shaft between the thigh frame and the swing frame is hollow inside and has several circumferentially distributed angle slots along the axial direction. A limiting pin is inserted into the hinge shaft, and the side of the limiting pin protrudes, with the protruding part fitting into a single angle slot. A movable groove is opened inside the front end of the horizontal part of the thigh frame, and a contact section is opened at the hinge shaft of the swing frame corresponding to the movable groove. The contact section exposes the angle slot, allowing the portion of the limiting pin within the angle slot to be exposed. A driving rod and a driven rod, capable of swinging back and forth, are sequentially installed in the movable groove, with the rear end of the driven rod corresponding to... The top of the thigh frame has a groove and a movable slider is installed. The front end of the active rod is in contact with the contact section. When the rear end of the active rod swings downward, the rear end of the driven rod swings upward. When the swing frame rotates and drives the limiting pin to rotate, the protruding part of the limiting pin can push the active rod upward until the upper end of the active rod contacts the thigh frame. At this time, the active rod limits and fixes the swing frame and drives the rear end of the driven rod to swing upward. The rear end of the driven rod swings upward, thereby pushing the slider upward. The upward push of the slider causes the thigh part to be pressed, thereby reminding the patient that the angle limited by the limiting pin has been reached. An angle sensor is coaxially mounted on the left end of the hinge axis between the thigh frame and the swing frame. The angle sensor can monitor the swing angle of the swing frame. The angle sensor is electrically connected to a calculation and control module. The calculation and control module includes a display screen, a calculation module, and a control module. The calculation and control module can receive the data monitored by the angle sensor, and can display the angle change in real time and calculate the angular velocity of the swing frame to obtain the knee joint movement speed, which can be displayed in real time. The control module within the calculation control module can control the start and stop of the electric push rod, and can set an angle threshold. When the electric push rod is started and the set angle is reached, the control module can control the electric push rod to stop running. Furthermore, a bushing is installed at the end of the electric push rod, and the bushing is hinged to the hinge seat through a movable shaft. The movable shaft can be pulled out along the axis of both, thereby separating the electric push rod from the swing frame. The patient can choose whether to use the electric push rod according to their needs.

[0006] Furthermore, the telescopic frame is equipped with a foot pedal at the front end, and a fixing strap is connected to the telescopic frame. The fixing strap is adjusted and fixed by a ladder buckle, which can fix the lower leg of different patients and improve the stability during training.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention utilizes a mechanical angle limiting and feedback linkage structure formed by the hinge shaft, limiting pin, active rod, driven rod, and slider of the thigh frame and swing frame. The limiting pin limits the swing angle by engaging with the angle groove inside the hinge shaft. When the swing frame rotates, causing the limiting pin to rotate, the protruding part of the limiting pin pushes up the active rod. The active rod, in conjunction with the rear end of the driven rod, swings upward and pushes the slider upward to press the patient's thigh, achieving mechanical tactile feedback and limiting fixation to achieve the target angle. This allows for precise control of the knee joint training angle, while simultaneously providing tactile feedback to the patient through the pressing of the slider.

[0008] 2. An angle sensor is coaxially installed at the left end of the hinge shaft. The angle sensor is electrically connected to the calculation and control module. The angle sensor monitors the swing angle of the swing frame in real time and transmits it to the calculation and control module. The calculation module calculates the swing angular velocity based on the angle data to obtain the knee joint movement speed. The control module can set the angle threshold and control the start and stop of the electric push rod. At the same time, the display screen displays the angle and speed data in real time. The angle sensor and the calculation and control module work together to achieve accurate monitoring and display of angle and speed. The electric push rod can be started and stopped by the control module and can be separated from the swing frame by pulling out the movable shaft, realizing flexible switching between electric assisted passive training and manual active training to meet the different needs of patients.

[0009] 3. The support frame consists of a base and a thigh frame nested together, with threaded pins and positioning holes for height adjustment. The calf frame consists of a telescopic frame and a swing frame nested together for length adjustment. The telescopic frame is equipped with a fixing strap and a ladder buckle, and a foot pedal at the front. The horizontal part of the thigh frame is padded. It can adapt to the body shape needs of patients with different heights and leg lengths. The fixing strap is adjusted and fixed to the calf through the ladder buckle. The foot pedal and padded pad improve wearing comfort and ensure stability and comfort for different patients during training. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments are briefly introduced below.

[0011] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention; Figure 2 This is a partial internal structure schematic diagram of Embodiment 1 of the present invention; Figure 3 This is a side view of Embodiment 1 of the present invention; Figure 4 yes Figure 3 Sectional view of part A.

[0012] The structural names represented by each number in the attached diagram are as follows: 1-Support frame, 2-Base, 201-Positioning hole, 202-Threaded pin, 3-Thigh bracket, 301-Soft pad, 302-Modular slot, 4-Lower leg bracket, 5-Telescopic frame, 501-Pedal, 502-Fixing strap, 6-Swing frame, 601-Hinge seat, 602-Angle slot, 603-Contact section, 7-Electric push rod, 701-Busset, 702-Modular shaft, 8-Angle sensor, 9-Calculation control module, 10-Limit pin, 11-Active rod, 12-Driven rod, 13-Slider. Detailed Implementation

[0013] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0014] Example 1 See Figures 1 to 4 As shown, this embodiment provides a specific implementation of a knee joint range of motion trainer that combines angle sensing and biofeedback. The trainer includes a support frame 1 and a lower leg frame 4, which are hinged together. The support frame 1 consists of a base 2 and a thigh frame 3 nested together. The base 2 has several vertically formed positioning holes 201. The thigh frame 3 has threaded pins 202 that engage with the positioning holes 201. By engaging the threaded pins 202 with different positioning holes 201, the overall height of the support frame 1 can be adjusted. The thigh frame 3 is inverted L-shaped, and a soft pad 301 is provided at the top of its horizontal portion.

[0015] The lower leg support 4 and the front of the horizontal section of the thigh support 3 are hinged together. The lower leg support 4 is composed of a telescopic frame 5 and a swing frame 6 nested together. It adopts the same nesting adjustment method as the support frame 1 and can be adjusted to fit the length of the patient's lower leg. The telescopic frame 5 has a footrest 501 at the front end for the patient to place their feet. The telescopic frame 5 is connected to a fixing strap 502, which is used with a ladder buckle to adjust the length and fix the patient's lower leg to prevent the leg from slipping during training.

[0016] The swing frame 6 and the thigh frame 3 are rotatably connected by a hinge shaft. The hinge shaft is hollow inside and has several circumferentially distributed angle slots 602 along the axial direction. A limit pin 10 is inserted into the hinge shaft. The side of the limit pin 10 has a protruding part that can fit into a single angle slot 602. When the hinge shaft rotates, it can drive the limit pin 10 to rotate. The front end of the horizontal part of the thigh frame 3 has a movable groove 302. The hinge shaft of the swing frame 6 has a contact section 603 corresponding to the movable groove 302. The contact section 603 exposes the angle slots 602 and the limit pin 10. The movable groove 302 is equipped with a swinging active rod 11 and a driven rod 12. The top of the thigh frame 3 has a groove corresponding to the rear end of the driven rod 12. A movable slider 13 is installed in the groove. The front end of the driving rod 11 is in contact with the contact section 603. When the hinge shaft rotates, the limiting pin 10 drives the front end of the driving rod 11 upward. When the rear end of the driving rod 11 swings downward, it can drive the rear end of the driven rod 12 to swing upward.

[0017] The swing frame 6 has a hinge seat 601 on its lower side. The hinge seat 601 is hinged to the electric push rod 7 via a bushing 701. A pluggable movable shaft 702 is installed between the bushing 701 and the hinge seat 601. By pulling out the movable shaft 702 along the axial direction, the electric push rod 7 can be separated from the swing frame 6. The other end of the electric push rod 7 is hinged to the inner side of the vertical part of the thigh frame 3, and is used to drive the lower leg frame 4 to swing actively, providing power for passive training.

[0018] The left end of the hinge shaft is coaxially mounted with angle sensor 8, which is an incremental rotary encoder used to monitor the swing angle of the swing frame 6. Angle sensor 8 is electrically connected to the calculation and control module 9, which includes an LCD touchscreen, a microcontroller, and a control unit. Its working principle is as follows: angle sensor 8 transmits the collected angle signal to the microcontroller, which calculates the knee joint movement speed through continuous angle differences. The display shows the angle and speed data in real time. The control module pre-stores angle thresholds and compares the current angle with the threshold in real time, thereby controlling the start and stop of the electric push rod 7.

[0019] Usage Procedure: First, adjust the nesting length of the base 2 and thigh support 3 by engaging the threaded pin 202 with the positioning hole 201 to adjust the height of the support frame 1. Then, adjust the nesting length of the telescopic frame 5 and the swing frame 6 to fit the patient's limb size. The patient sits on the training chair, placing their thigh on the soft pad 301 of the thigh support 3, with their lower leg against the telescopic frame 5 and their foot on the pedal 501. The lower leg is then secured using the ladder buckle adjustment strap 502. Select the training mode as needed. If passive training is required, maintain the connection between the electric push rod 7 and the swing frame 6. Set the target angle threshold through the calculation control module 9, activate the electric push rod 7, and the electric push rod 7 will drive the swing frame 6 to swing the lower leg, assisting in the movement. During knee joint movement, when the swing angle reaches a set threshold, the control module stops the electric push rod 7. For active training, the movable shaft 702 is pulled out to separate the electric push rod 7 from the swing frame 6. The limiting pin 10 is manually inserted, with its protruding part engaging with the target angle slot 602 within the hinge shaft. The patient actively flexes and extends the knee joint, causing the swing frame 6 to rotate. When the protruding part of the limiting pin 10 pushes the active rod 11 until its upper end contacts the thigh frame 3, the active rod 11 limits and fixes the swing frame 6. Simultaneously, it drives the rear end of the driven rod 12 to swing upward. The driven rod 12 pushes the slider 13 upward, and the slider 13 presses against the patient's thigh, reminding the patient that the specified angle has been reached. During training, the angle sensor 8 monitors the swing angle in real time, and the control module 9 calculates and displays the knee joint movement speed synchronously.

[0020] For those skilled in the art, various modifications and variations can be made to the above embodiments without departing from the principles of the present invention, and all such modifications and variations should fall within the protection scope of the present invention.

Claims

1. A knee joint range of motion trainer combining angle sensing and biofeedback, characterized in that, The system includes a support frame (1) and a lower leg frame (4). The support frame (1) includes a thigh frame (3). The lower leg frame (4) is hinged to the front of the horizontal part of the thigh frame (3). The lower leg frame (4) includes a swing frame (6). The swing frame (6) is hinged to the thigh frame (3). The hinge shaft between the thigh frame (3) and the swing frame (6) is hollow inside. Several circumferentially distributed angle slots (602) are opened in the hinge shaft along the axial direction. A limiting pin (10) is inserted into the hinge shaft. The limiting pin (10) has a protruding part on its side. The protruding part can fit with a single angle slot (602). The thigh frame (3) The front end of the horizontal part is provided with a movable groove (302), and the hinge shaft of the swing frame (6) is provided with a contact section (603) corresponding to the movable groove (302). The contact section (603) exposes the angle slot (602). The movable groove (302) is provided with a swinging active rod (11) and a driven rod (12) in sequence. The top of the thigh frame (3) is provided with a groove corresponding to the rear end of the driven rod (12) and a movable slider (13) is installed. The front end of the active rod (11) is in contact with the contact section (603). When the rear end of the active rod (11) swings downward, it drives the rear end of the driven rod (12) to swing upward. An angle sensor (8) is coaxially mounted on the left end of the hinge axis between the thigh frame (3) and the swing frame (6). The angle sensor (8) can monitor the swing angle of the swing frame (6). The angle sensor (8) is electrically connected to a calculation control module (9). The calculation control module (9) includes a display screen, a calculation module, and a control module. The calculation control module (9) is used to receive the data monitored by the angle sensor (8), calculate the swing angular velocity of the swing frame (6) through the calculation module to obtain the knee joint movement speed and display it in real time. The swing frame (6) is provided with a hinge seat (601) on the lower side, and an electric push rod (7) is hinged to the hinge seat (601). The other end of the electric push rod (7) is hinged to the inner side of the vertical part of the thigh frame (3). The control module is used to control the start and stop of the electric push rod (7). The control module can set an angle threshold. When the electric push rod (7) drives the lower leg frame (4) to swing to the set angle, the control module controls the electric push rod (7) to stop running.

2. The knee joint range of motion trainer combining angle sensing and biofeedback according to claim 1, characterized in that: The support frame (1) also includes a base (2), which is nested with the thigh frame (3). The base (2) has several vertically opened positioning holes (201), and the thigh frame (3) is equipped with threaded pins (202) that fit with the positioning holes (201).

3. The knee joint range of motion trainer combining angle sensing and biofeedback according to claim 1, characterized in that: The lower leg frame (4) also includes a telescopic frame (5), which is nested with the swing frame (6).

4. The knee joint range of motion trainer combining angle sensing and biofeedback according to claim 1, characterized in that: The thigh support (3) is inverted L-shaped, and its horizontal part is provided with a soft pad (301) at the top.

5. The knee joint range of motion trainer combining angle sensing and biofeedback according to claim 1, characterized in that: A bushing (701) is installed at the end of the electric push rod (7). The bushing (701) and the hinge seat (601) are hinged by a movable shaft (702). The movable shaft (702) can be pulled out along the axis of the two to separate the electric push rod (7) from the swing frame (6).

6. The knee joint range of motion trainer combining angle sensing and biofeedback according to claim 3, characterized in that: The telescopic frame (5) is provided with a footboard (501) at the front end. A fixing strap (502) is connected to the telescopic frame (5). The fixing strap (502) is adjusted and fixed by a ladder buckle to fix the lower leg.

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