A SEATING DEVICE FOR REDUCING REPETITIVE STRAIN INJURY

Abstract: A seating device for alleviating repetitive strain injuries, comprises dynamic means such as a pneumatically operable pillow which is forced to change shape over an extended period of time. The pillow is usable preferably as a seat but can be a backrest, alternatively, separate seat and backrest pillows are provided on a single chair. Each pillow may be divided into a plurality of segments, inflatable independently to provide up, down, backwards, forwards or side-to-side movement so that the joints and muscles of the limbs of the user are movable to change their operative position and thereby relieve strain.

Description: A SEATING DEVICE FOR REDUCING REPETITIVE STRAIN INJURY Field of the Invention: This invention relates to a seating device for reducing the risk or the occurrence of physical discomfort. Such discomfort may arise from Repetitive Strain Injury which is known to be caused by repeated, substantially identical movements and in particular arm, wrist or finger movements over a long period when operating typewriters, computers, and any manually operable devices, for example, in an office or manufacturing environment, or, in the home. Additionally, many people suffer back pain after many hours working in the same position. Background of the Invention: Repetitive strain injuries have been recognised for some time as such and can be experienced by secretaries, for example, typing on a computer keyboard for long periods, or by people working on production lines, where their bodies remain substantially in the same position at their workstations. In the past, attempts have been made to meet the problem of repetitive strain injury by making static improvements to chairs, for example, more comfortable and adjustable and by alterations in the designs of keyboards. None of these improvements have been sufficiently effective, because, it is believed, the user remains in a substantially fixed position in relation to his work. Repetitive strain injury remains an important cause of absenteeism and, increasingly, results in litigation. Summary of the Invention Therefore it is an object of the present invention to reduce the risk or the occurrence of the above mentioned physical discomfort, by providing a means for constantly altering the angles of the user's arms and shoulder joints in relation to his work station, so that the movements of the various joints and muscles of the upper limbs (including the wrists and hands), are made essentially non-repetitive. According to one aspect of the present invention a seating device is provided which comprises dynamic means to alter, over an extended period of time, the position of its user in relation to his work station. According to another aspect of the present invention there is provided a seating device for alleviating repetitive strain injuries comprising a seating arrangement, and dynamic means operable to tilt the seat backwards and forwards over an extended period of time so that the joints and muscles of the upper limbs of the user are movable. The dynamic means whereby the position of the user is altered, is preferably pneumatic. It may consist of a pillow in the seat cushion, which is intermittently inflated to alter the height of the user's body. The inflation cycle should be sufficiently slow as to make the movement imperceptible, perhaps 1-2 minutes inflation followed by 1-2 minutes deflation. However, much longer periods up to 10 minutes or even 20 minutes are possible. Alternatively or in addition, during the inflation or deflation period of the seat pillow, a similar pillow in the backrest of the chair may inflate and deflate, tilting the user's body towards and away from his work station. It is thought, however, that mere tilting alone is unlikely to provide as much benefit as raising the seat. The pillows may be divided into separate compartments whose individual inflation may either augment the above actions or add side-to-side movement. The average height of the chair seat and the average angle of the back support may be adjusted by the user for his/her own comfort before using the device. By average height of the seat, or average angle of the backrest of a chair is meant the height at which a user of the chair would set the seat, or the angle at which the user of the chair would set the backrest, for their personal comfort. Preferably, the above-mentioned movements are continuous. They may be provided randomly or cyclically. Reciprocal cyclical inflation of seat and back pillows may be provided by a standard compressor such as that which is described in Applicants' co-pending British Patent Application No. 9818318.9. Alternatively, the above-mentioned movements of the chair user may be produced mechanically by raising, and lowering, tilting and/or side-to-side movement of part or the whole of the chair. Brief Description of the Drawings. Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a perspective view of a known secretarial chair; Figure 2 is a perspective view of one form of secretarial chair in accordance with the present invention; Figure 3 is a cross-sectional view of a seating device for use with the chair of Figure 2; Figure 4 is a cross-sectional view of a backrest for the chair shown in Figure 2; and Figure 5 is a cross-sectional view similar to Figure 3 but including an alternative seating device. Description of the Embodiments: In the description which follows all like parts bear the same reference numerals throughout the various Figures. More particularly, and with regard to a known secretarial type chair 1 of Figure 1 , there is provided a padded seat 2 supported on an elongate hollow leg 3 having five legs extending radially outwardly from one end 3 a thereof. The seating device is movable on rollers 4 across the ground or floor 5. A backrest 6 is mounted on the seat and can be fixed, or, slidably mounted for adjustment of the height of the backrest relative to the seat. The seat 2 is conveniently in the form of a semi-rigid flat plate 7 which is mounted on the elongate hollow leg 3 at an end thereof opposite to that end on which the rollers 4 are located. The plate 7 is mounted to extend substantially radially relative to an elongate central axis 8 of the leg. The seat 2 (Figures 3 and 4) can be of a resilient foam 9 laid on the plate 7 and is covered with a cloth layer or layers 10 mounted on the seat to provide a suitable external surface 11 for the seat. Various releasable clamping devices are mounted on the leg 3 and the seat 2 for adjusting the height of the seat relative to the rollers 4, or alternatively the backrest 6 relative to the seat 2. These clamping devices do not form part of this invention and therefore are not described further. The backrest 6 is similarly provided by a foam foundation covered with a cloth. The backrest is adjustable in height relative to the seat 2 using a well known lock arrangement 14 (again not described in detail) which is mounted on a loop 13 fixed on the backrest 6. The loops 13 are located over arm 12 and the clamping device is unlocked to enable the height of the backrest to be adjusted relative to the seat by moving the backrest up or down the arm 12. Figure 2 illustrates an alternative form of seating device which is substantially as described with reference to Figure 1, except that the seat 2 and/or the backrest 6 are of a single compartment hollow pillow construction in accordance with the teachings of the present invention. More than one compartment may be provided in each pillow. Figures 3 and 4 show further details of the seat 2 and backrest 6 of Figures 1 or 2. The seat 3 in the embodiment of Figures 3 or 4 comprises seat plate 7 which is connected with a spindle 16 sealingly insertable in a cylinder housing 17 so that the height of the seat is adjustable pneumatically. Lever lock 18 on cylinder housing 17 is useful for locking the height of the seat. A pneumatically adjustable pillow 20 is mounted on the plate and a cloth cover 10 covers the pillow. The pillow 20 comprises an inflatable volume which is preferably a single compartment but which can be divided into two independently inflatable compartments 21, 22 located at the back and front respectively of the seat. There may be provided in each compartment a slit valve 23 to allow air forced into the compartment during an inflation phase to leave the compartment during a following deflation phase. Air is supplied by a compressor 24. The compressor 24 is preferably located beneath the seat 2 in an enlarged part 25 of the housing adapted to receive spindle 16. The compressor may additionally be used for raising or lowering the height of the seat and/or backrest, but its main task is inflating/deflating the compartments in the back and seat pillows using a pneumatic control circuit which can, for example, be of the type which is disclosed in our co-opending British Patent Application referred to above. The backrest 6 is also inflatable/deflatable in a similar manner to the pillow of the seat so that it is also tilted backwards and forwards in the same alternating time sequence as the seat and preferably under control of the same control circuitry. That is, when the seat pillow deflates or the front edge 26 of the seat tilts down the top 27 of the backrest tilts forwards so that the backrest 6 moves in sequence with the seat 2 thereby ensuring that the user's arms move from a different position each time and any strain is not repetitive. The net result is a considerable reduction in repetitive strain injury. Referring to Figure 5 there is illustrated a further embodiment which is similar in construction to the embodiment of Figure 3. However, in addition, a semi-rigid plate T is placed above the rigid plate 7. The semi-rigid plate T is inverted and an inflatable pillow 10' is sandwiched between the two plates 7, 7'. A foam cushion or foam seat padding 30 is located on top 31 of the semi-rigid plate 7', and a cover material 10" is located over the whole of the seat construction and fixed at 33 beneath the rigid plate 7. The seat is movable relative to the rigid plate 7 by inflating all the pillow to raise the seat relative to the fixed plate. When the inflatable pillow is formed of one or more compartments, the compartments are inflated selectively so that the seat device tilts back or forth, or from side-to-side relative to the rigid plate 7. The pneumatically controlled movement of the pillow has the effect of moving the semi-rigid plate T . The particular advantage known to exist in using the semi-rigid plate T in the manner described is a more controlled and accurate movement of the plate 7' and hence the seat 2. Therefore, as the seat 2 moves the person occupying the seat is moved in a manner substantially as hereinbefore described to ensure the person is not the subject of repetitive strain injury in their hands, fingers, shoulders arms, legs or feet, or back pain by ensuring the person's posture changes slightly in one or more directions and the risk of injury through repetitive movement is reduced. In any of the embodiments described herein the pillow used in the seat 2 or back-rest 6 can be divided into two compartments with a dividing membrane extending across the centre of the pillow across the seat 2 intermediate front and back edges of the seat 2. Additional compartments can be arranged to extend along the whole or part of side edges of the seat to provide side-to-side movement of the seat or back-rest. In one alternative embodiment the pillow may have a plurality of compartments extending radially outwardly from the centre of the seat whereupon selective inflation of the compartments provides front to back, or side-to-side movement of seat or back-rest. Therefore, although the seat pillow has been described as having one compartment it may have two or more compartments to enable forwards and backwards tilting. There may be provided one or more additional compartments which when inflated/deflated provide side-to-side movement of the seat in addition to the forward/backward tilting motion. When arms are attached to the chair, the arms may be adapted to move up and down with the side to which they are attached relative to the seat. The backrest pillow can be similarly constructed so as to tilt from side- to-side in correspondence with movement of the seat thereby altering the angles at which the upper limb joints are functioning while working on a keyboard or workstation. Any of the constructions described needs only to provide a very slow cyclic movement requiring small amounts of air, so only a small quiet air compressor is required which may be of the type disclosed in British Patent Application No. 9818318.9. but which is quieter because of the very slow operation thereof. The movement of the seat 3 and backrest 6 can be by pneumatic rams such as spindle 16 of leg 3 in the central housing/pillar of the leg. In a further, alternative embodiment the various movements of the chair can be controlled electronically by electric motors or mechanically by rotating or sliding shafts relative to the central pillar. The chair movements, particularly the height of the seat, can alternatively be varied by varying the height of the rollers on which the chair is movable, by pneumatic, electrical or mechanical operating arrangements. Having thus described the invention by reference to specific embodiments, it is to be well appreciated that the embodiments are in all respects exemplary and that modifications and vaπations thereto are possible without depaπure from the spiπt and scope of the invention For example, rather than using a pillow or cushion with selectively inflatable/deflatable compartments to achieve the desired motion of the seat and/or backrest, electromechanical or hydraulic/pneumatic actuators could be employed to move the basic seat/backrest surfaces

Claims: CLAIMS: 1. A seating device comprising dynamic means to alter, over an extended period of time, the position of its user in relation to his work station. 2. A seating device for alleviating repetitive strain injuries comprising a seat, and dynamic means operable to tilt the seat backwards and forwards over an extended period of time so that the joints and muscles of the upper limbs of the user are movable. 3. A device as claimed in claim 1 or claim 2, wherein the dynamic means is a pneumatically operative device. 4. A device as claimed in claim 3, wherein the pneumatic device is a pillow in a seat cushion which is intermittently inflated to alter the height of a user's body or to move it side-to-side. 5. A device as claimed in claim 4, including a pneumatically operable pillow in a backrest of the seating device for moving the user's body towards and away from a workstation. 6. A device as claimed in claim 4 or claim 5, wherein the pillows for the seat or backrest are divided into segments which are each inflatable/deflatable separately from the adjacent segments. 7. A device as claimed in any preceding claim, wherein movement is continuous. 8. A device as claimed in any of claims 1 to 7, wherein movement is random. 9. A device as claimed in any of claims 1 to 7, wherein movement is cyclical. 10. A device as claimed in claim 5 or claim 6, wherein reciprocal cyclic inflation/deflation of seat and backrest pillows are responsive to the output of a compressor. 11. A device as claimed in any of claims 2 to 9, wherein the movements of the seat are effected mechanically by raising, lowering, tilting, backwards, forwards and side-to-side a part or whole of the chair. 12. A device as claimed in claim 1 1, wherein movement of the seat and backrest are controlled electronically by operating electric motors. 13. A device as claimed in any of claims 5 to 11, wherein movement of the seat and backrest are controlled mechanically with rotating cam shafts or sliding cam shafts which move relative to a central pillar supporting the seat or backrest. 14. A device as claimed in any of claims 4 to 13, wherein the pillow includes a slit valve through which air is arranged to flow following the beginning of a deflation cycle. 15. A device as claimed in any of claims 1 to 14, wherein the inflation cycle is arranged to be sufficiently slow as to make the movement imperceptible. 16. A device as claimed in claim 15, wherein the inflation/deflation cycle is each of 1 to 2 minutes duration. 17. A device as claimed in claim 15, wherein the inflation cycle is 20 minutes or longer followed by a 20 minute deflation cycle. 18. A device as claimed in claim 15 . wherein the inflation/deflation cycle is each of 10 minutes duration. 19. A device as claimed in any one of the preceding claims, wherein the seating device is a chair. 20. A device as claimed in claim 19, wherein an average height of the chair is adjustable. 21. A device as claimed in claim 19 or 20, wherein an average angle of the backrest is adjustable. 22. A device as claimed in claim 19, wherein the chair includes a compressor located beneath the seat for inflating the pillows of each of the seat and backrest. 23. A device as claimed in any of claims 19 to 22, wherein the seat for the chair comprises a semi-rigid plate on which an inflatable pillow is located. 24. A device as claimed in claim 23, comprising a further semi-rigid plate located on the pillow to sandwich the pillow between the plates whereby inflation of the pillow raises or tilts the further semi-rigid plate. 25. A device as claimed in claim 24, comprising a layer of foam defining cushioning or padding located on the further semi-rigid plate, and a cloth layer as a seat cover for covering the foam, semi-rigid plates and pillow. 26. A device as claimed in any one of claims 19 to 25, wherein the chair includes a backrest having an inflatable pillow.

Inventors: GARDNER ARTHUR MICHAEL NEWSON, GARDNER, ARTHUR, MICHAEL, NEWSON
Applicants: GARDNER ANDREW DAVID, GARDNER ARTHUR MICHAEL NEWSON, GARDNER JAMES HASSAL, GARDNER TIMOTHY DUNCAN MICHAEL, GARDNER, ANDREW, DAVID, GARDNER, ARTHUR, MICHAEL, NEWSON, GARDNER, JAMES, HASSAL, GARDNER, TIMOTHY, DUNCAN, MICHAEL
Application year: 2000
Main classification: A47C7
IPC codes: A47C4, A47C7