WO2000059345A1 - A seating device for reducing repetitive strain injury - Google Patents

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.