Technical Field

The present invention relates to a shower chair of the type which permits a caregiver to move a patient (i.e. a sick and/or disabled person) into and out of the shower, and to wash the patient in the shower without having to move them from the chair.

Background Art

Shower chairs have been available for a number of years. The basic form of a shower chair is a chair where the back and seat cushions are covered with a waterproof material, so that the chair can be used in the shower without damage. A number of shower chairs also are adapted to be used as commode chairs, by providing a seat cushion with a central gap, so that the chair can be wheeled over a standard lavatory. Alternatively, commode facilities can be provided by fitting a container underneath the central gap of the seat cushion.

Obese patients pose particular problems in that their weight makes them difficult for a caregiver to manoeuvre, and they frequently have skin folds which readily become infected if they are not cleaned thoroughly and regularly. However, to clean the skin folds, the patient needs to be moved from a sitting position into as near a lying-flat position as possible.

Obviously, one way to overcome this difficulty is to support an obese patient in the shower in a full-length cradle which holds the patient in a lying-flat position. However, a cradle of this type takes up a great deal of space (i.e. has a large "footprint"), is awkward to manoeuvre, and cannot be used as a commode.

A further obstacle faced by caregivers is the height at which they must work:- washing a patient supported in a normal height chair means the caregiver needs to bend right down to reach many of the areas of the patent which have to be washed, and this notoriously produces back problems for the caregiver. Designing either a cradle or a chair so that the patient is at a comfortable height for washing by a caregiver results in a high structure which cannot safely be moved around.

Designers have sought to overcome the above described problems by providing a chair based shower chair which can be raised and lowered, and which can be tilted backwards from the normal chair position. This is an improvement, in that it allows the caregiver to work at a comfortable height, but without sacrificing stability when the chair is moved. However, it does not overcome the problem of moving the patient from a sitting position to close to a lying-flat position so that the patient can be thoroughly washed, because even when the chair is tilted backwards, the back and seat of the chair remain at the normal "sitting" orientation i.e. approximately 90 degrees.

Some of the more sophisticated chair designs have a facility for reclining the back of the seat, but there is no provision for raising the level of the seat and back. Further, such chairs are not designed to be used in a shower, or as a commode.

Terminology

As used herein, the terms set out below have the meanings indicated:

· "lift" means to move upwards vertically;

• "tilt" means to alter the angle of the plane of the seat to the horizontal, whilst keeping the angle between the planes of the seat and the back substantially constant;

• "recline" means to alter the angle between the plane of the seat and the plane of the back from approximately 90 degrees (normal sitting position) to an obtuse angle;

"shear" means the frictional force which occurs when two surfaces slide across each other. When one of these surfaces is a patient's back and the other of the surfaces is the back of a chair or shower chair, the patient's skin can be damaged by the shear.

Disclosure of Invention

An object of the invention is the provision of a shower chair which allows the transport of even an obese patient in a comfortable sitting position, at a safe and stable height, but which also allows the patient to be raised to a comfortable working position for the caregiver, and in addition permits the patient to be moved to positions in which thorough washing is possible.

The present invention provides a shower chair which includes a wheeled base supporting a seat and a back; the shower chair further includes at least two telescopic rams arranged such that the seat and the back can be raised, lowered, tilted, and reclined. In a preferred embodiment, the present invention provides a shower chair which includes:

a wheeled base supporting a seat and a back;

a first telescopic ram connected between said seat and said base; a second telescopic ram connected between said seat and said back;

said seat, said back, and said first and second rams being interconnected such that the chair can be moved between:

a sitting position in which the planes of the seat and the back are substantially perpendicular and the plane of the seat is substantially horizontal;

a raised and tilted position in which the planes of the seat and the back are substantially perpendicular and the plane of the seat is at an angle of up to 60 degrees to the horizontal and is raised compared to the sitting position; a raised and reclining position in which the plane of the seat is at an acute angle to the horizontal and is raised compared to the sitting position and the plane of the back is at an angle of up to 150 degrees to the plane of the seat.

Preferably, both rams, plus the connections between the rams, the seat and the back, are on one side only of the chair, so as to leave easy access to the patient from the other side of the chair, and to leave a completely clear space beneath at least the central area of the seat.

As used herein, the terms "substantially perpendicular" and "substantially horizontal" refer to the perceptions of a patient sitting in the chair rather than to an exact geometrical definition. Thus, when the planes of the seat and back are described as being "substantially perpendicular", this means that to a patient sitting in the chair, the chair is in the normal upright position.

Similarly, when the plane of the seat is described as being "substantially horizontal" this means that to a patient sitting in the chair, the seat provides a support which the patient perceives as being flat. Preferably, the shower chair also is a commode chair and the seat is formed with a central gap.

Preferably also, each of the telescopic rams is electrically powered, preferably from a battery mounted on the chair. Preferably also, the chair is equipped with a sensor designed to sense the angle of the seat to the horizontal, and to prevent the seat from being tilted forwards; this prevents a patient from inadvertently sliding out of the chair.

In a preferred embodiment of the shower chair, the lower end of said first ram is pivotally secured adjacent the base by a first pivot, and the upper end of said first ram is pivotably secured to a first armrest support by a second pivot, with said second pivot lying in a plane above the plane of said seat; said first armrest support also is pivoted to the upper end of a seat hanger by a third pivot, the lower end of said first seat hanger being rigidly secured to one side of said seat. A second seat hanger is rigidly secured at its lower end to the opposite side of the seat and the upper end of said second seat hanger is pivoted to a second armrest support by a fourth pivot.

Preferably each of said first and second armrest supports is rigidly secured to the back of the chair, and the upper end of each of said first and second armrest supports is pivoted by respectively fifth and sixth pivots to a corresponding rigid support mounted upon the base, such that the back and the first and second armrest supports together form a rigid assembly which is pivotable about said fifth and sixth pivots by extension or contraction of said first ram. Preferably also, the location of said third and fourth pivots relative to the plane of the seat is such that the height of said third and fourth pivots above the plane of the seat approximates to the position of the hip joints of a person seated upon the seat in use.

Preferably the lower end of said second ram is pivotally supported from the seat by a seventh pivot, with the seventh pivot lying in a plane below the plane of said seat, and the upper end of said second ram is pivoted to the back, adjacent the top of the back, by an eighth pivot.

Brief Description of the Drawings

By way of example only, a preferred embodiment of the present invention is described in detail, with reference to the accompanying drawings in which:- Figure 1 is a side view of a shower chair in accordance with the present invention, with the seat and back of the chair in the conventional "sitting" position;

Figure 2 is a side view similar to that of Figure 1 , but with the seat and back of the chair in a raised "reclining" position;

Figure 3 is a side view similar to that of Figure 1 , but with the seat and back of the chair in a raised 'tilted" position;

Figure 4 is a front view of the shower chair, with the seat and back of the chair in the position shown in Figure 1 ; and

Figure 5 is a back view of the shower chair, with the seat back of the chair and the position shown in Figure 1 .

Best Mode for Carrying out the Invention

Referring to the drawings, a shower chair 10 in accordance with the present invention consists of a base 1 1 consisting of a pair of spaced, parallel side rails 12 and a front rail 13 rigidly secured together with the length of the front rail perpendicular to the lengths of the side rails. The base 1 1 is mounted on four wheels 14 pivotally mounted one at each corner of the base; each of the wheels is provided with a brake 15 which can be moved against the corresponding wheel to secure the chair in a selected position.

A seat 16 and a back 17 are supported above the base 1 1 as described below. The seat 16 and back 17 are formed from a metal framework; both may be formed as a substantially rectangular framework with one or more intermediate bracing bars, as shown. The top bar 18 of the back 17 normally supports a pivoted head rest (not shown) of known type.

The seat 16 and back 17 are provided with waterproof cushions (removed for clarity). If the chair also is to be used as a commode chair, the seat 16 and the seat cushion both have a central gap.

On one side of the chair only, a first telescopic extendable ram 20 is mounted substantially vertical and is pivoted by a first pivot 22 at its lower end to a bracket 21 on one side 12 of the base 1 1 . The upper end of the ram 20 is pivoted to an armrest support 23 by a second pivot 24. The armrest support 23 also is pivoted to the upper end of a seat hanger 25 by a third pivot 26. The lower end of the seat hanger 25 is rigidly secured to one of the side rails of the seat 16. A second seat hanger 27 is rigidly secured at its lower end to the opposite side rail of the seat 16, and the upper end of the seat hanger 27 is pivoted by a fourth pivot 28 to the other armrest support 29.

Each of the armrest supports 23, 29 provides a slot 23a, 29a (Figure 4 only) into each of which armrests 50 (only one of which is visible) can be removably mounted (Figures 1 -3 only). The armrests 50 are depicted as un-padded, but may of course be padded. The curved outer end 50a of each armrest allows the armrests to be used as push/pull handles as well.

Each of the armrest supports 23, 29 also is rigidly secured to the adjacent end of the lower horizontal member 17a of the back 17, partway along the length of the armrest support. The end of each armrest support 23, 29 also is pivoted by fifth and sixth pivots 32, 33 to an angled support 34, 35 which extends from that end of the armrest support to a vertical support 36, 37 located one at each side of the rear of the chair. The lower end of each vertical support is rigidly secured to the adjacent side rail 12 of the base.

A second telescopic extendable ram 40 is mounted on the same side of the chair as the first ram 20. The lower end of the ram 40 is pivoted by a seventh pivot 43 to a bracket 44 which is rigidly secured to the underside of the seat 16, adjacent the rear of the seat. The ram 40 is pivoted at its upper end by an eighth pivot 41 to a mounting plate 42 secured to the back 17, adjacent the top rail 18.

A push-bar 51 , which provides a handle for pushing the chair, extends horizontally across the back of the chair (see Figure 4). The ends of the bar 51 are supported at one side upon the upper end of the vertical support 37 and at the other side upon a bracket 52 which is supported from the other vertical support 36. The bracket 52 is L- shaped to provide room for the upper end of the second ram 40 and its associated motor 40a. A crash protection bracket (not shown) may be mounted behind the lower end of the ram 40, to protect it against accidental impacts. The first and second rams 20, 40 both are telescopic extendable electrically powered rams, (commonly called "linear actuators"); although other means of extending the rams could be substituted. As shown, power is supplied to the rams by means of cables mounted within the chair frame, connecting the ram motors 20a, 40a to a control box and battery (not shown) which may be mounted at any suitable position on the chair base 1 1 , or may be built-in, e.g. into the chair back. The ram motors 20a, 40a can be driven in forward or reverse mode to extend or retract the corresponding rams, and are controlled by a hand-held electronic controller, normally controlled by the caregiver (or by the patient), in known manner.

Pivoted leg rests and/or footrests of known type (not shown) are fitted to the front of the seat 16, in known manner.

The above described chair is used as follows:- the rams 20, 40 are moved to the positions shown in Figure 1 , so that the ram 20 is nearly fully retracted, the ram 40 is extended, leaving the seat 16 and back 17 at, or close to, perpendicular to each other. In this position, the chair 10 is suitable for supporting a patient in a normal sitting position. In this position, with the patient's feet supported upon the footrests, the patient can comfortably and securely be wheeled into a shower, by a caregiver pushing the chair from the push bar 51 . If the patient is to be wheeled for any significant distance, some patients feel more comfortable and secure if the seat 16 and back 17 are slightly tilted, so that the patient is inclined slightly towards the back of the chair. This may be achieved by a small adjustment of the ram 20.

In addition, if the chair is also adapted as a commode chair as described above, the patient either can be wheeled over a conventional lavatory, or can use a receptacle secured underneath the chair seat, while sitting in this position.

When the chair is positioned in the shower, the brakes 15 are applied to each of the wheels 14, by the caregiver pressing down the brakes onto the wheels in known manner, so that the chair is secured in position. For the patient to be at a comfortable height for the caregiver to wash the patient, the patient must be raised to a suitable working level for the caregiver. At the same time, the patient must be reclined, and possibly also tilted, for thorough cleaning.

Reclining is achieved by both raising the seat 16 and inclining the back 17, to the approximate position shown in Figure 2, so that the patient is not only sitting at a higher level but also is moved progressively from a sitting position to a reclining position.

In the sitting position (Figure 1 ) the plane of the back 17 and the seat 16 are, or are close to, substantially perpendicular to each other. In the reclining position (Figure 2) the plane of the back 17 and seat 16 are inclined at an obtuse angle of up to 150 degrees.

To avoid shear, with the consequent risk of damage to the patient's skin, it is important that the pivot axis of the back 17 relative to the seat 16 (i.e., pivots 26/28) is as close as possible to the patient's own "pivot point", i.e. the hip joint.

It should be noted that the back 17 and the armrest supports 23/29 form a rigid assembly which pivots around the pivots 32/33. The ram 20 pushes on this assembly at the pivot 24, raising and tilting the back 17 and the armrest supports around the pivots 32/33.

The pivots 26/28 support the hangers 25/27 of the seat assembly 16, and the pivots 26/28 are positioned relative to the plane of the seat such that they approximate the hip joint position of the patient, thus minimising shear when the patient is moved to and from the reclining position.

The ram 40 controls the angle between the seat 16 and the back 17 in that movement of the ram 40 pivots the seat around the pivots 26/28.

It should be noted that the above described pivot points are arranged such that the centre of gravity of the chair remains as close as possible to constant during the various movements of the seat and back. This is important for stability and patient security.

The move to the reclining position is achieved by gradually extending the first ram 20 in the direction of arrow A and simultaneously retracting the second ram 40:- extending the first ram 20 raises the arm support 23 and, because the arm supports 23, 29 are linked together via the back 17, raises the arm support 29 also. As the arm supports 23, 29 are raised from the position of Figure 1 towards the position of Figure 2, and the second ram 40 is retracted, the lower edge of the back 17, which is secured to the arm supports 23, 29 rises with the arm supports and the upper edge of the back 17 swings in the direction of arrow X in Figure 1 , until the plane of the back 17 is at an obtuse angle to the plane of the seat 16, which remains substantially horizontal.

Assuming that the patient's back remains in contact with the back 17, the above described movements mean that the patient is slowly and gently moved from a sitting position to a semi reclining position, whilst rising to a height comfortable for the caregiver.

Moving the patient to a reclining position as described above enables access to the patient's skin folds on the upper side of the body, for thorough washing. In addition, the seat may be raised to a height comfortable for the caregiver to work, and the seat and back tilted, so that the plane of the seat is inclined at an acute angle to the horizontal, but the planes of the seat and back remain substantially perpendicular to each other, to allow the caregiver better access for washing the underside of the patient's body.

To tilt the chair as shown in Figure 3, the following sequence is used: starting from the position shown in Figure 1 , i.e. with the seat 16 at normal seating height and the back 17 with the plane of the back more-or-less perpendicular to the plane of the seat, the ram 20 is extended so that the planes of the seat 16 and back 17 are maintained at approximately 90 degrees to each other, but the plane of the seat 16 is tilted to an angle of up to 60 degrees to the horizontal, as shown in Figure 3. The patient can then be returned to a normal seating position simply by retracting ram 20. Obviously, any degree of tilt up to approximately 60 degrees can be achieved, simply by increasing or decreasing the extension of the ram 20.

It is envisaged that the reclining position will provide an angle between the planes of the back and the seat of up to 150 degrees, and the tilt position will incline the plane of the seat at up to 60 degrees to the horizontal.

To bring the patent back to a sitting position after washing has been completed, the above-described movements are reversed by retracting the first ram 20 and extending the second ram 40, moving the seat downwards at the direction of arrow B and swinging the back 17 in the direction of arrow Y. It will be appreciated that a patient need not be fully reclined, nor need the seat 16 be lifted to the full extension of ram 20:- the degree of lift and the degree of reclining or tilt can be controlled by the caregiver to provide the optimum position.

The controls of the rams 20,40, may be arranged so that the carer can control both independently, or (preferably) they are interlinked to provide a selection of predetermined changes of position.

It should be noted that, as described above, the "reclining" movement and the "tilting" movement both require raising the seat 16 and back 17 as well:- the "reclining" movement is a "raise and recline" movement; the "tilt" movement is a "raise and tilt" movement.

It is believed that the above described chair will cater for patients up to a weight of at least approximately 350 KG. However, if necessary the chair could be constructed with heavier-duty members, to cater for even heavier patients.

In all of the above-described positions, the centre of gravity of the chair remains as close as possible to neutral, ensuring that the chair remains stable in all positions.

The main components of the chair may be made from any suitably strong impact resistant material, preferably one which is easy to clean to hospital-grade cleaning standards, such as stainless steel.