NL2024907B1 - Moving aid for a (fore)arm comprising an overload protection - Google Patents

Abstract

Moving aid for the (fore)arm of a person, comprising, a support, said support being mountable to a carrier, such as a (wheel)chair, an armrest, for receiving the (fore)arm of a person, wherein the armrest is connected to the support, a plurality of arms, said arms mutually rotatably connected about an axis of rotation, wherein the rotation is controlled by a balancing force exerting element, and wherein said arms connect the armrest to the support, and at least one axis of rotation of said arms comprises an overload protection, wherein said overload protection is configured to offset two arms, around a mutual axis of rotation with respect to each other, upon exertion, either directly or indirectly, of an external torque on the mutual axis which torque exceeds than a predetermined torque.

Description

Moving aid for a (fore)arm comprising an overload protection This invention relates to a moving aid for people, in particular for a moving aid for the (fore)arm of a person.

Moving aids as such are known in the art. They serve to assist (partly) disabled persons to perform functions they are not able to perform without help, or which cost them extraordinary much effort.

In many cases this is done by supporting the (fore)arm in a certain position, or by providing a movable support for the (fore)arm with respect to a (wheel)chair and/or bed and/or stand. The support is then arranged for moving along with the arm, and may or may not be powered in order to ease the movement for a user.

In general, these aids provide an improvement in the well-being of the person, but still there are some disadvantages associated with them. In particular, the arrangements on (wheel-) chairs are voluminous, which causes — in the case of a wheelchair — for instance trouble when trying to pass through doors and other small openings. The moving aids are often fragile, and hence easily damage. In particular, the joints are often not compatible with either unexpected, sudden, and high loads, such as an external force and/or torque. The joints of the moving aid tend to be the most fragile part of the moving aid, and repairing them is a specialist and expensive operation. Furthermore, the operation of the existing aids is in many cases still intensive and exhausting for their users.

For that reason, and in general for providing a useful alternative to the existing moving aids, it is a goal of the present invention to provide a moving aid that at least partly lacks the above disadvantages, and that provides benefits over the prior art.

The present invention thereto proposes a moving aid for the (fore)arm of a person, comprising a support, said support being mountable to a carrier, such as a (wheel)chair, an armrest, for receiving the (fore)arm of a person, wherein the armrest is connected to the support, a plurality of arms, said arms mutually rotatably connected about an axis of rotation, wherein the rotation is controlled by a balancing force exerting element, and wherein said arms connect the armrest to the support, and at least one axis of rotation of said arms comprises an overload protection, wherein said overload protection is configured to offset two arms, around a mutual axis of rotation with respect to each other, upon exertion, either directly or indirectly, of an external torque on the mutual axis which torque exceeds than a predetermined torque.

The use of an overload protection increases the resistance to unexpected high loads on the moving aid such as a collision with a doorpost. This can occur since the person might not have well estimated the extent to which the moving aid extends from the wheelchair. However, due to the implementation of the overload protection the moving aid does not break. Instead of breaking, as a result of a torque applied to the moving aid, the moving aid offsets the respective arms to which the high torque is applied. The arms comprise joints, and the overload protection enables, upon application of a predetermined torque, the two respective arms attached to said joint to shift at an angle with respect to each other. This results in a new “uncalibrated mostly unwanted” position of the moving aid. Instead of repairing the entire moving aid, a recalibration of the arms, which are offset by the overload protection, will bring the moving aid back in its original state. The offset between said arms is related to the severity or extend of the impact. A higher or longer impact will yield a bigger offset between said arms. The offset can only be a multiple of 11.25 degrees. lt is also possible to have an offset which is bigger or smaller than a multiple of 11.25 degrees. The predetermined torque which initiated the overload protection can be applied directly or indirectly to the overload protection. Wherein the indirect application of the torque is related to the overload protections which do not coincide with the axis of rotation of the joint between two arms. In a further embodiment of the present invention, the at least one overload protection comprises at least one locking element and a receiver, for receiving said locking element, wherein the locking element and receiver can rotate together around the mutual axis in a first locked position, and wherein, upon exceeding the predetermined external torque, the locking element and receiver move relative to each other from the first locked position to a second locked position which is arranged at an angle with respect to the first locked position around the mutual axis. The overload protection can be reused by the way it is designed. The locking element and receiver can engage with one another. Once the overload protection is activated, by means of application of a big external force and/or torque, the locking element and receiver move to a different locked position. This different locked position is visible since the arms are shifted over an angle. The moving aid can still be used in this shifted position by the user. However, ideally the overload position is reconfigured into its original position. This reconfiguration after activation of the overload protection can be performed without the intervention of service personnel. In yet a further embodiment the at least one locking element and receiver are coaxially placed. This allows for a compact design, which is favourable for the user. A more compact design also decreases the chance of hitting an obstruction with the moving aid. Besides that, the compact design is also lighter an thereby easier to operate by the user. Furthermore, in a yet further embodiment the concentric overload protection coincides with the axis of rotation. This allows also to realise a more compact design of the moving aid.

In a further embodiment the overload protection is placed at a location distal to the axis of rotation, but within the length of one of the arms connected to said axis of rotation, wherein the overload protection is configured to offset the arms through a transmission. it might be the case that the moving aid does not provide enough space in a specific joint for placing the overload protection in said joint. In that case, the overload protection can be placed elsewhere. By placing the overload protection elsewhere, said joint can be constructed as small as possible which allows for both a better behaviour of the moving aid as well as a better visual representation of the moving aid. If the overload protection is located at a distal location, it might be connected to the respective axis of rotation through a transmission. Such a transmission can be constructed by any means chosen from the group of; wires, chains, gears or arms.

The force exerting element in a different embodiment further comprises a damper, for damping momentum of the moving aid. The damper is damps the undesired movement which might be introduced by the force exerting element, for instance as diclosed in the Dutch patent application NL2015541 by the same applicant. It has been found that in exceptional cases the force exerting element can initiate an undesired movement of the moving aid. In such a case the damper has shown to reduce this effect and allow for a more reliable use of the moving aid. In a different embodiment of the present invention the overload protection further comprises a tensioner, for configuring the required external predetermined torque for offsetting the arms connected through a mutual axis of rotation. Since the moving aid should be usable by all kinds of people it is important to introduce flexibility into the moving aid. In this case, the flexibility relates to the tensioner of the overload protection. The tensioner can configure the external torque before the overload protection offsets the arms. In a further embodiment the tensioner is composed out of a spring and an adjustable bias mechanism, wherein the bias mechanism is configured to adjust the tension. The spring can for example be a disk spring, and the adjustable bias mechanism can be formed by a bolt. Also the size of the disk spring could change the measure of pretension.

In a different embodiment the overload protection and tensioner are all placed concentrically. This specific embodiment further increases the compactness of the moving aid. The overload protection and tensioner can be located either concentrically with the mutual axis of rotation of said overload protection mechanism and concentrically with the axis of rotation of a joint, or the overload protection and tensioner might in the case of a distally located overload protection be located concentrically with the mutual axis of the distally located overload protection.

In another embodiment the moving aid comprises at least two axes of rotation, and wherein the moving aid comprises multiple overload protections. This increases the possibilities of movement of the moving aid. Preferably the at least two axes of rotation are placed substantially perpendicular to one another. In a further alternative embodiment the overload protection comprises 32 locking positions and 8 locking pins, wherein subsequent locking positions are rotated 11.25 degrees with respect to each other. This allows for multiple locked positions of the arms connected by the joint. Because of that, the user can still comfortably use the moving aid in case of a small offset caused by the overload protection. The time before necessarily fixing the moving aid can thus be extended and that increases the comfort of use.

In a different embodiment the overload protection is attached to a bracket. This allows for a preferred installation of the arms of the moving aid, as disclosed in Dutch patent application NL 2015541 by the same applicant. In a further 5 embodiment the overload protection and bracket can be locked in a preferred position by intercoupling means, in particular wherein the overload protection comprises coupling means formed by extruded holes and, wherein the bracket comprises coupling means formed by protruding pins, wherein said pins are dimensioned such that they can couple with the extruded holes of the overload protection, and more in particular wherein the number of holes is greater than the number of pins, and the angular offset of the holes and pins is compatible, forming a number of intercoupling positions for installing the moving aid in a preferred position. This further optimizes the personalization and setting possibilities of the moving aid.

The invention according to a non-limitative embodiment will now be elucidated more specifically based on the following figures; - figure 1, which schematically shows the moving aid according to the present invention, and; - figure 2, which shows the implementation of the overload protection in the moving aid. Figure 1 shows the moving aid 1 for the (fore)arm of a person, comprising a support 2, said support being mountable to a carrier, such as a (wheel)chair and/or stand, an armrest 3, for receiving the (fore)arm of a person, wherein the armrest is connected to the support 2, a plurality of arms 4, said arms mutually rotatably connected about an axis of rotation 5, wherein the rotation is controlled by a force exerting element, and wherein said arms connect the armrest 3 to the support 2, and at least one axis of rotation 5 of said arms comprises an overload protection, wherein said overload protection is configured to offset two arms 4, around a mutual axis of rotation with respect to each other, upon exertion, either directly or indirectly of an external torque and/or force on the mutual axis which torque exceeds than a predetermined torque.

Figure 2 shows the overload protection 6, wherein said overload protection 6 is configured to offset two arms 4, around a mutual axis of rotation 7 with respect to each other, upon exertion, either directly or indirectly of an external torque or force on the mutual axis which torque exceeds than a predetermined torque.

The overload protection 6 comprises at least one locking element 8, and a receiver 9,

for receiving said locking element 8, wherein the locking element 8 and receiver 9 can rotate together around the mutual axis 7 in a first locked position, and wherein, upon exceeding the predetermined external torque, the locking element 8 and receiver 9 move relative to each other from the first locked position to a second locked position which is arranged at an angle with respect to the first locked position around the mutual axis 7. In this embodiment the at least one locking element 8 and receiver 9 are coaxially placed.

However, the coaxial overload protection 6 does not coincide with the axis of rotation.

Instead the overload protection 6 is placed at a location distal to the axis of rotation, but within the length of one of the arms connected to said axis of rotation, wherein the overload protection 6 is configured to offset the arms 4 through a transmission 10. Furthermore, the overload protection 6 further comprises a tensioner 11, for configuring the required external predetermined torque for offsetting the arms connected through a mutual axis of rotation 7. The tensioner 11 is composed out of a spring 12 and an adjustable bias mechanism 13, wherein the bias mechanism is configured to adjust the tension.

In this embodiment the spring 12 is a disk spring 12, and wherein the bias mechanism 13 is a bolt 13, wherein the bolt 13 and disk spring 12 are placed concentrically.

In this embodiment the overload protection 6 is also placed concentrically with the tensioner 11. The overload protection 6 is attached to a bracket 14.

Claims (14)

Conclusions Movement aid for the (lower) arm of a person, comprising: - a support, which support can be mounted on a carrier such as a (wheel) chair; - an armrest for receiving the (lower) arm of a person, the armrest being connected to the support; - a plurality of arms which are mutually rotatably connected about an axis of rotation, the rotation being controlled by a balancing element, and the arms connecting the armrest to the support, and characterized in that the at least one rotational axis of the arms comprises an overload protection, wherein the overload protection is designed to adjust two arms relative to each other about a mutual axis of rotation, while exerting, directly or indirectly, an external torsion moment and/or torsion force on the mutual axis, whereby the torsion moment is greater is then a predetermined torsion moment. Movement aid according to claim 1, wherein at least one overload protection comprises: - at least one locking element, and - a receiver which receives the locking element, wherein the locking element and the receiver are rotatable together about the mutual axis in a first locking position, and wherein, when exceeded of the particularly determined external torsional moment, the locking element and the receiver move relative to each other from the first locking position to the second locking position provided at an angle to the first locking position about the relative axis. Movement aid according to claim 2, wherein the at least one locking element and the receiver are in coaxial position. Movement aid according to claim 3, wherein the coaxial overload protection coincides with the rotation axis. Movement aid according to any one of claims 1 to 3, wherein the overload protection is arranged at a distance from the rotation axis, but within the length of one of the arms connected to the rotation axis, the overload protection is arranged to to adjust the arms by means of a transmission. Movement aid as claimed in any of the foregoing claims, wherein the force exerting element further comprises a damper for damping the impulse of the movement aid. Movement aid according to one of the preceding claims, wherein the overload protection further comprises a tensioner for adjusting the required, predetermined external torque for adjusting the arms connected by a mutual rotation axis. Movement aid according to claim 7, wherein the tensioner is composed of a spring and an adjustable adjustment mechanism, the adjustment mechanism being adapted to adjust the tension. Movement aid according to claim 8, wherein the spring is a disk spring, and wherein the adjusting mechanism is a bolt, wherein the bolt and the disk spring are placed concentrically. A motion aid according to any one of claims 7-9, wherein the overload protection and the tensioner are arranged concentrically. Movement aid according to one of the preceding claims, wherein the movement aid comprises at least two rotation axes, and wherein the movement aid comprises a number of overload protections. Movement aid according to one of the preceding claims, wherein the overload protection comprises 32 locking positions, successive locking positions being rotated at an angle of 11.25 degrees with respect to each other. A movement aid according to any one of the preceding claims, wherein the overload protection is arranged on a bracket. Movement aid according to claim 13, wherein the overload protection and the bracket can be locked in a preferred position by interlocking means, in particular wherein the overload protection comprises coupling means formed by extruded holes and, wherein the bracket comprises coupling means formed by projecting pins wherein the pins are sized to mate with the extruded holes of the overload protector, and more particularly wherein the number of holes is greater than the number of pins, and the angular difference of the holes and pins is compatible, and thus a number of mutual coupling positions for installing the motion aid in a preferred position.