GB2506664A

GB2506664A - An armrest arranged to allow lateral movement

Info

Publication number: GB2506664A
Application number: GB1217906.5A
Authority: GB
Inventors: Kah Ming Chan; Lee Humphries; David Smith
Original assignee: CAREFLEX Ltd
Current assignee: CAREFLEX Ltd
Priority date: 2012-10-05
Filing date: 2012-10-05
Publication date: 2014-04-09
Also published as: IE20130300A1; GB201217906D0

Abstract

An adjustable seat comprising a pair of armrests 9 extending from a seat frame wherein at least one armrest 9 is connected to the frame by two mountings 15 and 16 such that both mountings 15 and 16 can move laterally with respect to the seat and wherein a linkage 27 is provided between the mountings 15 and 16 such that movement of one mounting causes movement of the other. The mountings 15 and 16 may be arranged to rotate and the connections on the frame and armrest may form the corners of a parallelogram. The linkage 27 may be a rod. A spring loaded locking mechanism 29 may be provided to lock the armrest 9 in one of a number of positions and a release lever or tab 30 may be provided on the rear of the armrest 9. Movement of the armrest 9 allows the width of a seat to be adjusted and helps provide the correct posture.

Description

Variable Width Seat The present invention relates to a seat having an adjustable width and is particularly applicable to a specialist posture management static seating system, as may be used by the elderly or disabled. The invention may have applications to other seating and may for example be applicable to wheelchairs.

As the invention is particularly applicable to a specialist posture management static seating system. the invention will be described in the context of such a seating system.

However, this does not limit the scope of the invention, which is defined by the attached claims.

An occupant of a posture management seat, will normally sit in it for many hours each day and may depend on a nurse or carer to assist them to get out of the seat, to adjust the seat or even to adjust their posture within the seat. For this reason it is necessary that the seat has a number of independently adjustable components, for it is important that the occupant is correcdy supported to avoid any pressure points, which may lead to discomfort, a degradation of the body tissue or restricted circulation and the problems associated with this. It is particularly important to provide proper support to maintain an occupants posture.

For example. undue leaning could result in a scholiotic profile. where the spine curves to maintain an upright head position.

To address this, some known posture management seats have adjustable arms to control the width of the seat. The width between the arms. known as seat width, can be adjusted by having several pairs of arms in the form of saddles, with different pairs of arms being of different widths, so that a desired pair of arms may be selected and sat on the sides of the seat frame to provide a desired seat width. This is acceptable if the seat is to be tailored for a specific individual, but this is not suitable for multi-user environments, as for example in a care home or hospital. Also there are the ogistical problems and costs associated with providing multiple sets of arms for a seat.

An alternative known way of adjusting the seat width in a seat employs mechanical arrangements. These are normally embedded in the seat or arms and commonly require protective covers, provided for safety and hygiene purposes, to first be removed and then tools used to adjust internal adjustment mechanisms. Such mechanisms may be acceptable if a seat is to be tailored for a specific individual, although the provision of removable covers or flaps, or similar, which require fastenings such as hook and eye fastener tape are undesirable due to hygiene issues. However, in a multi user environment, in which such seats are often used, the time involved in adjusting the arms and the requirement to use tools, can results in such seats being used by successive occupants without the seat width being adjusted, thus the occupants are not correctly supported.

It is an object of the present invention to provide a seat with an improved seat width adjustment means.

According to the present invention there is provided a seat having an adjustable seat width, the seat comprising a frame and arms attached to the frame defining the seat width therebetween. wherein at least one arm has a seat width adjustment mechanism by which the arm is mounted to the frame, the adjustment mechanism complising a front mounting towards the front of the arm and a rear mounting towards the rear of the arm, each mountings permitting lateral movement between the arm and the frame, the adjustment mechanism further comprising a linkage between the front and rear mountings arranged such that lateral displacement of the arm at one mounting causes a substantially equal lateral displacement of the arm at the other mounting, the adjustment mechanism being arranged to permit the arm to be moved laterally relative to the seat, to narrow or widen the seat width, whilst substantially maintaining the arm in alignment with a longitudinal centreline of the seat. The seat width adjustment mechanism of the arm may be mounted fixed relative to the frame or to the arm.

An adjustable seat in accordance with the present invention permits the arm or arms to be attached to a frame of the seat via a mechanism that permits the arm to be moved laterally relative to a longitudinal centreline of the seat whilst remaining substantially parallel to the longitudinal centrehne of the seat. This in turn permits a single action to displace an arm to correctly adjust it.

Advantageously this is achieved by each mounting comprising a component at a fixed location relative to the arm and a component at a fixed location reladve to the frame, the four components defining a parallelogram for all positions of the arm relative to the frame, with the two components at fixed locations relative to the arm foiming one side of the parallelogram and the two components at fixed locations relative to the frame forming the other side of the parallelogram.

The single action required to laterally displace the arm whilst keeping it colTectly aligned preferably enables the adjustment mechanism to be arranged to permit the arm to simply be pushed or pulled laterally to narrow or widen the seat width, without the use of tools. This is particularly advantageous in a multi-user environment, as it will encourage a nurse or carer to correctly adjust the seat for each occupant of the seat.

As an alternative to the arm simply being pushed or pulled to adjust the seat width.

this may instead be achieved by the provision of a single lever, arm or knob that may be moved or rotated to cause the arm to be laterally displaced at both the front and rear mountings, to narrow or widen the seat width. This will provide similar advantages to the arrangement where the arms are pushed together or pulled apart.

According to one embodiment of the invention, each mounting may comprise a rotating member fixed to the arm having a connection point offset from the axis of rotation of the rotation member, by which connection points the arm is connected to the frame, the linkage extending between the rotating members to cause the rotating members to rotate together, wherein the two axes of rotation and connection points of the two rotating members define a parallelogram for any position of the arm relative to the frame.

Preferably, the axes of rotation of the two rotating members are substantially vertical. This will cause the connection points, offset from the axes of rotation, to move laterally inwards or outwards as the rotation members rotate. Alternativdy the rotation axes could be aligned parallel to the centreline of the seat, which would similady cause the connection points, offset from the axes of rotation, to move laterally inwards or outwards as the rotation members rotate.

The linkage mechanism may conveniently comprise a rod connected between the two rotation members to cause them to rotate together. However, any suitable mechanism may be employed, for example the linkage mechanism may comprise a toothed cog attached to or forming each rotating member, where the linkage comprises a toothed belt synchronising the position of the rotating members.

Preferably, the two axes of rotation and connection points define a parallelogram for any position of the arm relative to the frame, thus ensuring that the arm retains the same alignment as the rotation members rotate about their axes.

Preferably the connection points comprise respective pins attached to respective rotating members, each pin aligned substantially parallel to the respective axis of rotation of the associated rotation member, wherein the frame comprises sockets for receiving respective pins, such that the pins are rotatably retained in the sockets. In this manner the pins may provide the only points of physical support for the ann This may provide a convenient means by which the arm and adjustment mechanism may be secured to the seat, permitting the arm and adjustment mechanism to be easily removed from the seat should this be necessary, for example if the adjustment mechanism should fail or require maintenance.

Advantageously, the width adjustment mechanism comprises a locking mechanism for locking the mountings to prevent lateral displacement of the arm relative to the frame.

This permits the seat width to be correctly adjusted and then locked so that the arms cannot be separated and the seat width increased, either by deliberate or accidental movement.

Preferably, the locking mechanism may comprise an indexing system which can be locked in one of a predetermined number of positions, but alternatively this could be provided by a friction or clamping mechanism.

Preferably a release tab, or lever, is accessible to the rear of the arm and is connected to the locking mechathsrn. This will permit a nurse or carer standing behind the seat, or to the side of the seat, to operate the release tab or lever, to release the locking means to enable them to push the arm towards or away from the longitudinal centreline of the seat, to widen or narrow the seat width.

One embodiment of the present invention will now be described by way of example only. with reference to the accompanying figures. of which: Figure 1 is a side elevation of the seat in accordance with the present invention, with a side panel removed; Figure 2 is a perspective view of the seat frame and arm of the seat of Figure 1 with the arm ready to be mounted on the seat frame; Figure 3 corresponds to Figure 2 but shows the arm mounted on the seat frame with the arm in a position to maximise the seat width; Figure 4 corresponds to Figure 3 but with the arm in a position to minimise the seat width; Figure 5 is a perspective view showing the adjustment mechanism set to narrow the seat width, as shown in Figure 4; Figure 6 corresponds to Figure 5 but with the adjustment mechanism set to provide an intermediate seat width; and Figure 7 corresponds to Figures 5 and 6 but with the adjustment mechanism set to provide a maximum seat width.

Referring to Figure 1, there is illustrated a posture management seat, indicated generally as 1, which is in accordance with the present invention.

The posture management seat I comprises a frame 2 pivotally supported by bolts 3 (only one of which is shown) on a wheeled carriage 4. An actuator (not shown) acts between the carnage 4 and frame 3 to tilt the frame in a space, relative to the calTiage 4, to provide a tilt in space (TIS) capability, in a manner commonly used in posture management seating.

To either side of the seat frame are attached covers 5, the nearest of which is shown removed to reveal the seat frame 2. Mounted to the seat frame 2 is seat back 6, legrest 7, arms 8 and 9 (only arm 8 of which can be seen in Figure 1) and a seat cushion 10. The width between the arms 8 and 9 determines what is termed the seat width, to which an occupant is constrained by the arms 8 and 9. Thus, the arms 8 and 9 together with the shaped backrest 6 act to keep the occupants spine and hips correctly aligned when seated.

The frame of the backrest 6 is rdatively narrow in the region of the arms S and 9. so as not to obstruct the arms S and 9 moving inwards. However, this is not immediately evident to an occupant because a cushion (not shown) of the back rest extends the full width between the arms, even when they are set to maximise the seat width. The cushion is then compressed when the arms 8 and 9 are moved inwards to narrow the seat width.

Referring to Figure 2, an arm 9 is shown colTectly aligned ready for engagement with the seat frame 2. The seat frame 2 is provided with four sockets 11 to 14 and the aim 9 is mounted on the frame 2 by being pushed downwards, from the position illustrated in Figure 2, to that illustrated in Figure 3, where the pins 15 and 16 engage with the sockets 13 and 14 and are retained in place by spring circlips iSa and 16a.

The pins 15 and 16 can rotate in the sockets 13 and 14 and the arm 9 can be released from the frame 2 by compressing the spring circlips iSa and 16a, into the pins 15 and 16 and pulling the arm 9 upwards to release the pins 15 and 16 from sockets 13 and 14.

With reference to Figure 3. the seat pad 10 (not shown) of Figure 1, sits in the frame 2 on runners 17 (only one of which can be seen) on either side of the seat frame 2. The seat pad 10 substantially occupies the volume of the seat frame 2, such that bottom of the arm 9 is substantially level with the top of the seat pad 10. The arms 8 and 9 (only arm 9 of which is shown in Figure 3) are moveable laterally towards or away from a longitudinal centreline of the seat frame. In Figure 3, the aim 9 is in an outward position away from the centreline to maximise the seat width and in this position the inner edge of the arm 9 will be substantially aligned with the edge of the seat cushion 10. In Figure 4, the arm 9 is shown in an inward position towards the centreline where it will extend over the top edge of the seat cushion 10 and reduces the seat width to a minimum.

Referring to Figures 5 to 7, there is illustrated perspective underside views of the arm 9. showing the seat width adjustment mechanism, indicated generally as 20, in different positions. To more clearly show the linkage 27 of the adjustment mechanism 20 the arm 9 is shown reversed, relative to the position shown in Figures 2 to 4, so that the front of the arm in Figures 5 to 7 is to the left of the page.

The arm, indicated generally as 9, comprises an arm rest 18 fixed to casing 19 of adjustment mechanism 20. A master rotating member 21 is mounted towards the front end of casing 19 having a rotation axis 22. A slave rotating member 23 is mounted towards the rear of casing 19 and has a rotation axis 24, Each rotation member 21 and 23 has a respective arm 25 and 26 supporting pins 16 and 15. for engaging with the sockets 14 and 13 of the frame 2, shown in Figure 2.

Rotating members 21 and 23 are connected by a linkage bar 27. so that rotation of one of the rotation members 21 or 23 causes the other rotation member 23 or 21 to be rotated by a corresponding amount.

As can be seen from FigureS. rotation axes 22,24 and pins 15 and 16 form a parallelogram. Thus lateral displacement of one of the pins 15 or 16 will cause the other of the pins 16 or 15 to be displaced laterally by a corresponding amount. Lateral movement of the pins 15 and 16 is limited by peg 28 engaging with the slave rotating member 23.

The master rotating member 25 contains a spring loaded indexing system 29 which locks the master rotating member 21 in a number of predefined positions. The indexing system may be released by pulling release tab 30 attached to release wire 31, which in turn is connected to the indexing system 29. Puffing the release tab 30 permits the pins 15, 16 to move from the position shown in Figure 5, corresponding to an inward position of the arm 9 where the seat width will be a minimum, through the position shown in Figure 6 to the

S

position shown in Figure 7, corresponding to an outward position of the arm 9 where the seat width will be a maximum.

When the pins 15 and 16 are mounted in respective sockets 13 and 14 of the frame 2, (see Figure 2), pulling the release tab 30 permits the arm 9 to be moved inwardly from the outward position shown in Figure 3 to the inward position shown in Figure 4, thus narrowing the seat width. Similarly, when the tab 30 is pulled the the arm 8 and 9 can be pulled outwardly from the position shown in Figure 4 to the position shown in Figure 3 to widen the seat width.

The indexing system 29 on the arm 9 may be arranged to protrude through an aperture 32 in the casing 19, as shown, so as to permit the seat width to be adjusted by manually turning the indexing system once the release tab 30 has been pulled. This is the same on the arm 8 and the indexing system on this arm can be seen in Figure 1 protruding from aperture 33 in this aim 8.

Arm 9 has been described above with reference to Figures 2 to 7. The other arm 8 of the seat 1 (shown in Figure 1) is a mirror image of the arm 9 and is mounted in sockets II and 12 of the frame 2 and functions in the same manner as the aim 9. Although the arms 8 and 9 are mechanically independent of each other, they will normally be adjusted together to narrow or widen the seat width and if set to corresponding positions will cause the seat width to be centred on longitudinal centreline of the seat 1. This may be achieved by widening the aims 8 and 9 and thus the seat width, prior to an occupant sitting in the seat and then, when the occupant is seated centrally on the seat, pulling the tab on an arm and pushing it inwards until it abuts the occupants hips, before repeating the process for the other arm.

One embodiment of the present invention has been described by way of example only, however it will be appreciated that many modifications will occur to those skilled in the art without departing from the scope of the appended claims.

Claims

Claims 1. A seat having an adjustable seat width, the seat comprising a frame and arms attached to the frame defining the seat width therebetween, wherein at least one arm has a seat width adjustment mechanism by which the arm is mounted to the frame, the adjustment mechanism comprising a front mounting towards the front of the arm and a rear mounting towards the rear of the arm, each mountings permitting lateral movement between the arm and the frame, the adjustment mechanism further comprising a linkage between the front and rear mountings arranged such that lateral displacement of the arm at one mounting causes a substantially equal lateral displacement of the arm at the other mounting, the adjustment mechanism being arranged to permit the arm to be moved laterally relative to the frame, to narrow or widen the seat width, whilst substantially maintaining the arm iii alignment with a longitudinal centreline of the seat.
2. A seat as claimed in Claim 1 wherein each mounting comprises a component at a fixed location relative to the arm and a component at a fixed location reladve to the frame.the four components defining a parallelogram for all positions of the arm relative to the frame, with the two components at fixed locations relative to the arm forming one side of the parallelogram and the two components at fixed locations relative to the frame forming the other side of the parallelogram.
3. A seat as claimed in Claim 1 or 2 wherein the at least one aim may be pushed or pulled laterally to narrow or widen the seat width.
4. A seat as c'aimed in Claim I or 2 wherein a single lever, arm or knob may be moved or rotated to cause the arm to be laterally displaced at both the front and rear mountings to narrow or widen the seat width.
5. A seat as claimed in any preceding claim wherein each mounting comprises a rotating member fixed to the arm having a connection point offset from the axis of rotation of the rotation member by which connection points the arm is connected to the frame, the linkage extending between the rotating members to cause the rotating members to rotate together.
6. A seat as claimed in Claim 5, wherein the axes of rotation of the two rotating members are substantially vertical.
7. A seat as claimed in Claim S or 6, wherein the two axes of rotation and connection points of the two rotating members define a parallelogram for any position of the arm relative to the frame.
8. A seat as claimed in any one of Claims S to 7, wherein the connection points comprise respective pins attached to respective rotating members each pin aligned substantially parallel to the respective axis of rotation of the rotation member, wherein the frame comprises sockets for receiving respective pins such that the pins are rotatably retained in the sockets.
9. A seat as claimed in any preceding claim wherein the linkage comprises a rod.
10. A seat as claimed in any preceding claim, wherein the width adjustment mechanism further comprising a locking mechanism for the mountings to prevent lateral displacement of the arm relative to the frame.
11. A seat as claimed in Claim 10, wherein the locking mechanism comprises an indexing system which can be locked in one of a predetermined number of positions.
12. A seat as claimed in Claim 10 or 11, wherein the width adjustment mechanism further comprises a release tab or lever, accessible to the rear of the arm and connected to the locking mechanism by which release tab or lever the locking mechanism can be released.
13. A seat as claimed in any preceding claim, comprising two corresponding seat width adjustment mechanisms each associated with a respective arm of the seat to permit the seat width to be adjusted equally from each side of the seat.
14. A seat substantially as hereinbefore described with reference to, and/or as illustrated in, one or more of the accompanying drawings.