Training device with an extremity support and method for determining the force acting on an extremity support of a training device

Description

[0001] The invention relates to a training device for training at least one extremity, comprising a support frame and at least one crank arranged on a rotational axis associated with the support frame, and at least one extremity support that can be attached to the at least one crank at different radial distances from the rotational axis. The invention further relates to a method for determining the force acting on an extremity support of a training device.

[0002] Training devices of the type mentioned above are known, for example, from DE 10 2011 055 200 B3, US 2009 / 0 211 395 A1 and DE 295 08 072 U1, which are particularly suitable for the targeted training of individual muscle groups of the extremities, as is required in the rehabilitation of patients. Such training devices are also used in the leisure sector as sports equipment, for example as ergometers, or for the targeted training of top athletes. It should be noted that, particularly during the rehabilitation of patients, precise control of the loads is necessary, in particular the force acting on the extremity support. An example of this is the case of the use of an artificial hip, with the treating physician specifying that the load on the extremity with the artificial hip should not exceed a predetermined value during rehabilitation, for example 20 kg with the associated force.Since the training devices in question can be individually adapted to different users in the rehabilitation sector by changing the radial distance of the extremity support from the axis of rotation, this means that the load cannot be clearly determined from the acting torque due to the simple relationship: torque equals force x lever arm.

[0003] Alternatively, it is also possible for the training device to be equipped with a motor that provides a specific torque on the rotational axis for passive training. However, due to the aforementioned dependency, this torque cannot be clearly determined from the force acting on the patient without knowledge of the radial distance, thus jeopardizing the success of the rehabilitation or even causing damage to the patient's health. To avoid these disadvantages, it is known to assign sensors to the extremity support, for example a footrest for a leg, to record the acting force - namely strain gauge sensors. However, this has the disadvantage of significantly increasing the cost of the training device and thus placing a strain on the budget required for rehabilitation.

[0004] WO 2009 / 006673 A1 discloses a crank arm with a voltage amplifier. Document US 2009 / 211395 A1 discloses a training device according to the features of the preamble of claim 1.

[0005] The invention is therefore based on the object of designing a training device of the type mentioned at the outset in such a way that it is possible to control the force acting on the user of the training device in a simple and cost-effective manner.

[0006] A further object of the invention is to provide an improved method for determining the force acting on a limb support of a training device. The part of the object relating to the training device is achieved by a training device of the type mentioned above in that the radial distance detected by the device is fed as a measured value to the evaluation unit for calculating the force exerted on the limb support.

[0007] The invention is based on the realization that it is not only possible to directly measure the force on the extremity support, but that the force can also be determined as a derived quantity if, in addition to the acting torque, the radial distance of the extremity support from the axis of rotation is known. Therefore, the invention provides a means for detecting the radial distance of the extremity support from the axis of rotation, with the knowledge of this distance then being able to be determined in conjunction with the torque generated by the patient or the torque exerted on the patient. In healthy athletes, it can be assumed that there is symmetrical force development in the right and left extremities. However, this assumption is not always justified in the field of rehabilitation, so that each extremity support is advantageously assigned a corresponding means.The evaluation provided by the evaluation unit makes it possible to monitor targeted training and, if necessary, to influence the motor to reduce the generated drive torque or, in the sense of biofeedback, to signal to the patient that the generated force has been exceeded. The evaluation unit can also be supplemented by a display unit that displays the calculated force as a numerical value, so that the information provided to the patient or the physiotherapist is not limited to whether a threshold value has been reached or exceeded.

[0008] It is particularly preferred if the means formed by at least one sensor is selected from a group comprising Hall sensors, ultrasonic sensors, laser sensors and photoelectric cells as part of light barriers.

[0009] A training device with a sensor formed by a Hall sensor is characterized in that the Hall sensor is positioned on a circuit board arranged stationary to the axis of rotation, and that receptacles and / or an elongated hole are formed in the crank that passes by the circuit board, into which the extremity supports can be inserted with a pin containing a magnet. This offers the advantage that, as the crank passes by, the selected crank radius can be detected, i.e., the distance of the extremity supports from the axis of rotation. The Hall sensor can also detect whether a magnetic north pole or a magnetic south pole is passing by, so that the pin expediently has a bar magnet with a north-south polarity that is coaxial with the pin axis.This allows the extremity supports that can be inserted into the receptacles or the elongated hole to be divided into two clearly distinguishable groups, for example for leg training and arm training. For example, if for leg training the magnetic north pole is arranged on the side facing the crank and for arm training the magnetic south pole is arranged on the side facing the crank, i.e. the bar magnet is rotated 180°. It is also preferred that several Hall sensors are arranged on the circuit board, which is particularly advantageous when there are no discretely spaced receptacles, but rather an elongated hole or a corresponding link is used, since by using several sensors the position of the extremity support in the elongated hole can be continuously calculated by calculating the signals.

[0010] A further advantage arises when the Hall sensors arranged on the circuit board are arranged on a straight line that does not pass through the axis of rotation, i.e. the straight line defined by the Hall sensors is not in a strictly radial alignment, but is inclined relative to the radial alignment, since the crank position relative to the circuit board is always the same when the magnet passes by and thus the circuit board can also function as an index sensor.

[0011] Furthermore, the problem is solved by a training device with an extremity support that has a pin with a bar magnet with a north-south polarity aligned coaxially with the pin receptacle. Since such an extremity support, when used in training, can detect not only the passing of the magnet but also its orientation, the further possibility exists that the orientation of the polarity can be used to identify the accessory group.

[0012] The part of the problem relating to the method is solved by a method for determining the force acting on an extremity support of a training device, comprising the steps of positioning the extremity support, which can be fastened at different radial distances from the axis of rotation of the associated crank, on a crank at a radial distance from its axis of rotation and detecting the radial distance by means of at least one sensor and evaluating the measured value detected by the sensor in conjunction with a torque acting on the axis of rotation in an evaluation unit.

[0013] In the following, the invention is explained in more detail using exemplary embodiments shown in the drawing; in which: Figure 1 shows a schematic representation of a training device in a side view, Figure 2 shows an enlarged representation of the part of the training device required to explain the invention in a perspective view, Figure 3 shows a perspective view from a side view Figure 2 different angle, and Figure 4 a side view of the object from Figure 2 , shown without the extremity support.

[0014] In the Figure 1A training device 1 is shown that is suitable for training one pair of extremities, namely two legs. This exemplary embodiment serves only to explain the invention, which can also be used for training the other pair of extremities, namely the arms. The training device 1 has a support frame 2, which in the exemplary embodiment shown is arranged on preferably brakeable rollers 3. The exemplary embodiment has two cranks 4, which are arranged on a rotational axis 5 assigned to the support frame 2.Furthermore, the training device 1 has a motor 6 for driving the rotational axis 5 and two extremity supports 7, namely two foot shells 8, which can be fastened at different radial distances 9 from the rotational axis 5 of the respectively associated crank 4, namely in that in the embodiment shown, two receptacles 10 are formed in each crank 4, into which a pin 11 associated with the foot shell 8 can be inserted.

[0015] A means for detecting the radial distance 9 of the extremity support from the axis of rotation is provided, which is designed for automated detection, wherein the radial distance 9 detected by the means can be fed as a measured value to an evaluation unit 12 for calculating the force exerted on the extremity support 7 using the formula force = torque divided by lever arm, wherein the lever arm is given by the radial distance 9 of the extremity support 7 from the axis of rotation 5. The torque is generated by the motor 6 and is known or is applied by the patient, so that based on the detected torque and knowledge of the radial distance 9, the force derived from it can be monitored to determine whether the patient's training is effective and to avoid overloading.

[0016] Ultrasonic sensors, laser sensors, and photoelectric cells as part of light barriers are suitable for detecting the radial distance. In the illustrated embodiment, the use of Hall sensors 13 is shown, namely two Hall sensors positioned on a circuit board 14 arranged stationary relative to the rotation axis 5. Receptacles 10 are formed in the crank 4, which moves past the circuit board 14, into which receptacles the extremity supports 7 can be inserted with the pin 11 having a magnet 15. The receptacles 10 can also be combined to form a slot; more than two receptacles 10 can also be present in the crank 4. The pin 11 has a bar magnet with a north-south polarity that is coaxial with the pin axis, thus creating the possibility of distinguishing between two accessory groups, for example, for leg training and for arm training, which are characterized by the orientation of the bar magnet.

[0017] In particular from the Figure 2 and 4 It can be seen that several Hall sensors 13 are arranged on the circuit board 14, by which a straight line is defined that does not run through the axis of rotation 5, i.e. encloses an angle with a radial orientation, so that the crank position relative to the usable sensor is always the same when the magnet 15 passes by.

[0018] In the following, the use of the training device 1 and the necessary procedure for determining the force acting on an extremity support 7 are explained. For this purpose, the extremity support 7, i.e. the Figure 2The footrest 8 shown is positioned at a radial distance 9 from the axis of rotation 5 by inserting the pin 11 with the magnet 15 into one of the two shown receptacles 10. By aligning the bar magnet, with the magnetic north pole pointing, for example, towards the receptacle 10 of the crank, the extremity support 7 is identifiable as a footrest 8 to distinguish it, for example, from a support for arm training, in which the magnetic south pole points towards the receptacle 10.

[0019] With the two Hall sensors 13 arranged on the circuit board 14, the radial distance 9 of the foot shell 8 from the axis of rotation 5 can be determined in order to determine the force in conjunction with the torque acting on the axis of rotation 5 in an evaluation unit 12, which force is optionally output as a numerical value in a display unit 16. List of reference symbols

[0020] 1 Training device 2 Carrying frame 3 Roller 4 Crank 5 Rotation axis 6 Motor 7 Extremity support 8 Footrest 9 Radial distance 10 Mounting 11 Pin 12 Evaluation unit 13 Hall sensor 14 Circuit board 15 Magnet 16 Display unit

Claims

1. A training device for training at least one limb, with a support frame (2) and at least one crank (4) arranged on a rotational axis (5) associated with the support frame (2), and with at least one limb support (7) which can be fastened to the at least one crank (4) at different radial distances (9) from the axis of rotation (5), wherein a means for detecting the radial distance (9) of the at least one limb support (7) from the axis of rotation (5) is provided, wherein the means for automatically detecting the radial distance (9) of the limb support (7) from the axis of rotation (5) and is formed by a sensor, wherein the training device has an evaluation unit (12), characterized in that the radial distance (9) detected by the means is fed as a measured value to the evaluation unit (12) for calculating the force exerted on the limb support (7).

2. The training device according to claim 1, characterized in that the sensor is selected from a group comprising Hall sensors (13), ultrasonic sensors, laser sensors, and photoelectric cells as part of light barriers.

3. The training device according to claim 2, with a sensor formed by the Hall sensor (13), characterized in that the Hall sensor (13) is positioned on a circuit board (14) arranged stationary relative to the axis of rotation (5), and in that receptacles (10) are formed in the crank (4) passing the circuit board (14) and / or a slot are formed in the crank (4) passing past the circuit board (14) on the crank (4), into which the end support (7) with a pin (11) having a magnet (15) can be inserted.

4. The training device according to claim 3, characterized in that the pin (11) has a bar magnet with a north-south pole orientation that is coaxial with the pin axis.

5. The training device according to claim 3 or 4, characterized in that several Hall sensors (13) are arranged on the circuit board (14).

6. The training device according to claim 5, characterized in that the Hall sensors (13) arranged on the circuit board (14) are arranged on a straight line that does not pass through the axis of rotation (5).

7. The training device according to one of claims 1 to 6, characterized in that the limb support (7) has a pin (11) which has a bar magnet with a north-south pole orientation which is coaxial with the pin axis.

8. The training device according to claim 7, characterized in that the orientation of the pole alignment of the bar magnet can be used to identify the accessory group to which it belongs.

9. A method for determining the force acting on a limb support (7) of a training device (1), comprising the steps of positioning the limb support (7), which can be fixed at different radial distances (9) from the axis of rotation (5) of the associated crank (4), on a crank (4) at a radial distance (9) from its axis of rotation (5), detecting the radial distance (9) by means of at least one sensor, and evaluating the measured value detected by the sensor in conjunction with a torque acting on the axis of rotation (5) in an evaluation unit (12).