NL2015541B1

NL2015541B1 - Joint for a balanced arm support and arm support comprising such joint.

Info

Publication number: NL2015541B1
Application number: NL2015541A
Authority: NL
Inventors: De Jong Ralf; Martinus Petrus Van Oene Ericus; Christianus Maria Groenland Paulus; Petrus Hendricus Verstegen Paulus
Original assignee: Focal Meditech B V
Priority date: 2015-10-01
Filing date: 2015-10-01
Publication date: 2017-04-20

Abstract

The present invention relates to a Joint for a balanced arm support, comprising a first leg, rotatably connected to a second leg, about an axis of rotation, at least one balancing force exerting element, coupled to the first leg at a first engaging point; and coupled to the second leg, at a second engaging point; arranged for exerting a balancing force in a direction from the first engaging point to the second engaging point wherein the second engaging point is movable along a path on the second leg for adjusting the distance from the second engaging point to the axis of rotation and therewith the torque delivered by the balancing force; and wherein the angle of the balancing force exerting element with respect to the tangent of the path is releasably lockable in a position wherein the tangent is perpendicular to the direction of the force.

Description

Joint for a balanced arm support and arm support comprising such joint

The present invention relates to a joint for a balanced arm support, an arm support comprising such joint and a movable chair or other frame comprising such arm support. Balanced arm supports are used as an aid for those having difficulty in lifting their arm. The support may for instance provide a force that compensates at least partly for gravity, which enables a user of the support to use his available strength for making movements from a supported position.

The amount of support, in particular the force may be adjustable, not only to the specific wish or need of a user, but also to ever changing circumstances, such as an activity that is to be performed. In case of eating or lifting of an object, a different force may be required than in case of for instance eating. For that purpose, balanced arm supports may have adjustable forces.

These forces can be adjusted in several ways, depending on the construction of the arm support. In some cases for instance the (effective) length of a spring and therewith its force may be adjustable. However, when springs are involved, relatively high forces may be required to change settings of the arm support. For that reason, (mostly electric) actuators are usually applied to assist in changing settings. However, not only does this make the arm support more expensive, it also sets restrictions to the design and results in a generally more complex device.

It is therefore a goal of the present invention to provide an arm support that lacks the above disadvantages, or at least to provide a useful alternative to the state of the art.

The invention thereto proposes a joint for a balanced arm support, comprising a first leg, rotatably connected to a second leg about an axis of rotation, at least one balancing force exerting element, coupled to the first leg at a first engaging point and coupled to the second leg, at a second engaging point and adapted for exerting a balancing force in a direction from the first engaging point to the second engaging point wherein the second engaging point is movable along a path on the second leg for adjusting the distance from the second engaging point to the axis of rotation and therewith the torque delivered by the balancing force and wherein the angle of the balancing force exerting element with respect to the tangent of the path is releasably lockable in a position wherein the tangent at the second engaging point is perpendicular to the direction of the force.

The first leg may at its distal end from the joint be coupled to a so called fixed world, which may be part of a workingchair or other frame. The second leg may at its distal end from the joint comprise or be coupled to a carrier for a persons forearm. The torque at the joint is defined by a force times an arm, wherein the force may be caused by for instance a spring, while the arm is formed by the distance from the second engaging point to the axis of rotation. The torque can thus be adjusted by either changing the force caused by the spring, or by changing the arm.

The invention relates to a mechanism for changing the arm, which is provided by the second engaging point being movable along a path on the second leg for adjusting the distance from the second engaging point to the axis of rotation.

The balancing force exerting element exerts a force between the first and the second engaging point, which may have a component in the direction of the path. When the second engaging point is moved, said component of the balancing force has to be overcome.

For this may require a force that is too large for a person who wants to adjust the balancing torque, the general idea of the present invention is to eliminate, during adjustment, the component of the balancing force that impedes the adjustment.

This is done by locking the angle of the balancing force exerting element with respect to the tangent of the path in a position wherein the tangent at the second engaging point is perpendicular to the direction of the force, and while the angle is locked, adjusting the distance from the second engaging point to the axis of rotation.

The force exerting element may comprise at least one spring, and in certain embodiments at least one zero length spring. The second engaging point may be movable by arranging it on a slide that is movable along a track.

In an embodiment, the path is formed by a threaded end that is axially rotatable, and the second engaging point comprises a nut arranged about the threaded end, limited in its rotation, for translating upon rotation of the threaded end. The nut may this form the aforementioned slide. For manually rotating it, the threaded end preferably comprises a knob.

The joint may further comprise an indicator for indicating that the position wherein the tangent is perpendicular to the direction of the force is reached. This may be an optical indication, but the releasable lock may also comprises a hole that is outlined with a movable pin in the position wherein the tangent is perpendicular to the direction of the force, wherein the movable pin has a first mode wherein it is locked against movement into the hole, and a second mode, wherein it is movable towards the hole and forms the indicator. In this case, a person can put the pin in the second mode, move the legs about the axis of rotation until the pin locks in the hole, move the second engaging point and put the pin back in its first mode when finished.

The invention will now be elucidated into more detail with reference to the following figures. Herein:

Figure 1A shows a first view on a joint according to the present invention;

Figure IB shows a schematic representation of figure 1A; and

Figure 2 shows a second view on a joint according to the present invention. Figure 1A shows a first view on a joint according to the present invention. The figure shows a joint for a balanced arm support, comprising a first leg (1), rotatably connected to a second leg (2), about an axis of rotation (3), at least one balancing force exerting element (4), coupled to the first leg at a first engaging point (5); and coupled to the second leg, at a second engaging point (6); arranged for exerting a balancing force in a direction from the first engaging point (5) to the second engaging point (6); wherein the second engaging point is movable along a path (7) on the second leg (2) for adjusting the distance from the second engaging point (6) to the axis of rotation (3) and therewith the torque delivered and thereby the balancing force. The second engaging point (6) is positioned on a slide (8) that is movable along the threaded end (9).

The angle alpha of the balancing force exerting element with respect to the tangent of the path is releasably lockable in a position wherein the tangent is perpendicular to the direction of the force. Schematic view in figure IB shows the same parts schematically. Figure 2 shows a second view of the joint according to the invention. Same reference numbers refer to same parts here. Further visible here is the releasable lock, which comprises a hole 10 that is outlined with a movable pin 11 in the position wherein the tangent is perpendicular to the direction of the force. Angle alpha is 90 degrees in this case. The movable pin 11 has a first mode wherein it is locked against movement into the hole 10, and a second mode, wherein it is movable towards the hole 10 and also forms an indicator for indicating that the position wherein the tangent is perpendicular to the direction of the force is reached. The movable pin may for that purpose be spring tensioned in the direction B.

The above given examples are exemplary only and do not limit the scope of the present invention, as defined in the following claims.

Claims

A joint for a balanced armrest, comprising: - a first arm (1) rotatably connected to; - a second arm (2), about an axis of rotation (3); - at least one balancing force exerting element (4), coupled to the first arm at a first point of engagement (5); and o coupled to the second arm, at a second engagement point (6); - adapted to exert a balancing force in a direction from the first engagement point (5) to the second engagement point (6); wherein - the second engagement point is movable along a path (7) on the second arm (2) for adjusting the distance from the second engagement point (6) to the axis of rotation (3) and thereby the torque supplied by the balancing force; and wherein - the angle of the balancing force exerting element relative to the tangent line of the web can be releasably locked in a position where the tangent line is perpendicular to the direction of the force.

2. A joint according to claim 1, wherein the path is formed by a threaded end which is axially rotatable, and the second engagement point comprises a nut arranged around the threaded end, limited in its rotation, for translation upon rotation of the thread. threaded end.

The joint of claim 2, wherein the threaded end comprises a knob for manually rotating the threaded end.

A joint according to any one of the preceding claims, wherein the joint comprises an indicator for indicating that the position at which the tangent line is perpendicular to the direction of the force has been reached.

A joint according to any one of the preceding claims, wherein a releasable lock includes a hole aligned with a movable pin in the position where the tangent line is perpendicular to the direction of the force.

The joint of claims 4 and 5, wherein the movable pin has a first mode, which is locked against movement in the hole, and has a second mode, wherein it is movable toward the hole and forms the indicator.

The joint of claim 6, wherein the movable pin is under spring tension.

Armrest comprising a joint as claimed in any of the claims 1-7.

A movable chair or other frame comprising an armrest according to claim 8.

Method for adjusting a torque on a joint according to any one of the preceding claims, comprising the steps of: - locking the angle of the balancing force exerting element with respect to the tangent line of the track in a position where the tangent line is perpendicular is in the direction of the force; - adjusting the distance from the second engagement point to the axis of rotation and thereby the torque supplied by the balancing force; - releasing the angle of the balancing force exerting element with respect to the tangent line of the track.