GB2095547A - Beds - Google Patents

Abstract

A hospital bed, couch or a reclining chair comprises a frame (11) supporting a mattress platform (15) comprising four articulated sections of which one (17) forms a backrest, one (16) is fixed and two (19, 20) together form a knee break, the backrest and the knee break being movable independently of one another between lowered positions and raised positions. The knee break and the backrest have associated therewith counter-balance means (27, 28) urging them to the raised positions and brakes such as 29 operative to lock the sections in the lowered and desired raised positions. The counter-balance means comprise a gas spring (34) for the knee break and a combined gas and coiled compression spring for the backrest. The brakes are releasable by handles (32, 31) on the frame to permit movement of the knee break and the backrest. <IMAGE>

Description

SPECIFICATION Hospital bed with articulated mattress platform Description of Invention This invention related to beds and couches (hereinafter referred to generically as beds).

The invention has been devised especially for use in hospital beds and the following description will be confined to this application but it is to be understood that there is no limitation in this regard.

To improve the cornfort of a patient who is confined to bed, it is known to provia'e a hospital bed with a mattress platform comprising a number of articulatea' sections which are angularly movable relative to each other. The bed may also be provided with other facilities enabling the mattress platform as a whole to be lifted and lowered and/or tilted to a "head down" position and possibly to a ''foot down" position but the present invention is not concerned with these facilities.

Articulated mattress platforms customarily include one section forming a backrest which can be pivoted upwardly to an inclined position so that the patient can sit up with his or her back adequately supported. In some cir cumstances, such platforms also have two sections which are articulated together and are angularly movable relative to one another to provide a knee break to support the pa tient's legs behing the knees so as to avoid undue strain on the tendons at the back of the legs. The provision of a knee break also reduces the tendency for the patients to slip down the bed.

There are two main types of articulated mattress platform. in one type, the backrest and knee break sections are arranged for simultaneous movement. The sections are pivotally mounted on a frame or sub-frame of the bed by a suitable linkage, the articulation joints of the sections being spaced from the points at which the sections pivot with respect to the frame or sub-frame. In the other type of bed, known as the "Fowler" bed, the backrest section and knee break sections are separately operable.The backrest and one of the knee-break sections are pivotable about fixed points relative to a frame or sub-frarne of the bed and the other knee-break section is supported for movement relative to the frame or sub-frame. A mattress platform may consist of three or four sections, in the latter case a relatively fixed section being provided between the backrest section and the adjacent knee-break section.

A Fowler bed is generally considered to be more desirable from the medical point of view than the other type of bed, since the provision of a knee break may cause or aggravate circulatory problems in some patients and it should therefore be used only under the con enrol of the medical or nursing staff, which is only feasible when the knee-break is operable imdependently of the backrest.

The present invention has been devised for use with the Fowler type of bed but it is applicable to other forms of bed or couch with an articulated mattress platform.

A problem arises when the nursing staff want to adjust the position of the backrest and/or knee break while a patient (who may be quite heavy) is liying on the bed. Clearly, it would require considerable physical effort to lift both the mattress platform section or sections and the weight of the patient carried by that section or those sections. it has been proposed in the Fowler type of bed to operate the backrest and knee break by separate screw jack devices which remove the need for strong muscular effort on the part of the nursing staff but these devices are relatively slow to operate because of the high mechanical advantage given.

it is an object of the present invention to provide a bed which has an articulated mattress platform, with means enabling one or more of the sections of the platform to be Moved between a plurality of positions with out major physical effort, even when the bed is occupied.

According to the invention there is provided a bed comprising a frame and a mattress platform having a number of articulated mattress supporting sections angularly movable wilts respect to each other and to the frame between a lowered position and a raised position, wherein at least one of the sections has associated therewith counter-balance means tending to assist in raising the section, brake means normally operative to hold the section in the lowered position and means operable to release the brake means to permit raising of the section.

The counter-balance means may comprise spring means.

In a preferred form, the counter means may comprise a gas spring or a coiled compression spring or a combination of the two.

Alternative arrangements may have counterbalance means in the form of a coiled tension spring, a torsion spring or a counter balance weight.

The expression ''counter balance means'' is used herein to denote any means by which the weight of a mattress section and that proportion of a patient's body weight which it supports in use, is wholly or partly counterbalanced by the provision of a force acting opposite to such weight. When the bed is unoccupied, this force may in fact exceed the weight of the mattress section which would therefore rise automatically on release of the brake means. The counter-balance means may be considered as power assistance for raising the mattress section.

The bed may comprise three or four mat tress supporting sections, one of which constitutes a backrest at the head end of the bed and two of which, adjacent the foot end of the bed, form a knee break.

In a preferred embodiment, the backrest section and knee break sections can be moved independently of each other and separate counter-balance means are provided for the backrest and knee break, each counter-balance means being associated with a respective brake means.

The release means for the brake means associated with the backrest may be provided in a position accessible to a patient lying on the bed.

The release means for the brake means associated with the knee break may be provided at a position inaccessible to a patient lying on the bed.

In each case, the release means may comprise a lever handle opetatively connected to a Bowden cable.

The invention will now be described in more detail by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side view of one form of hospital bed embodying the invention; and Figure 2 is a longitudinal section of part of the bed.

The hospital bed illustrated in the drawings comprises a base generally indicated at 10, a main frame 11 mounted on an intermediate frame 1 2 and a linkage 1 3 disposed between the base and the intermediate frame. The linkage 1 3 is a scissor-type linkage operable by power means 14 to lift and lower the assembly of the main frame and the intermediate frame in generally known manner. The main frame is mounted on the intermediate frame for pivoting to a "head down" position and a "foot down" position, for example in the manner described and illustrated in the specification and drawings of our Patent Application No. 7900321.

The bed also includes a mattress platform generally indicated at 1 5 and comprising four articulated sections, namely a section 1 6 fixed to the main frame, a backrest section 1 7 articulated by joint 1 8 to the fixed section and two sections 1 9 and 20 which together form a knee break, the section 1 9 being articulated by joint 21 to the fixed section and the section 20 being articulated by joint 22 to the section 1 9. Thus, from the flat positions shown in full lines in Fig. 1 the backrest section can be pivoted upwardly to an inclined position 1 7a as shown in dotted lines and the knee-break sections can be raised to an inverted V position (not shown).The section 20 is guided by rollers carried by two links 23 at opposite sides of the bed as it is raised to the knee-break position. The links 23 are formed with slots which co-operate with pins 24 on the main frame 11 enabling the links to be moved to, and located in a position in which the knee-break sections are held in the position 19a, 20a shown in chain dotted lines for the treatment of vascular disorders.

Grab handles 25, 26 are provided on the sections 1 7 and 20 to enable the backrest and the knee-break to be lifted manually, with the assistance of two counter-balance means 27, 28 which are associated respectively with the knee break and backrest and act to compensate for the weight of the patient so that the backrest and knee break sections can be lifted, event when loaded with the weight of a patient, with relatively little physical effort.

Associated with the two counter-balance means are brake means 29, 30 which are operative to lock the backrest and the kneebreak in their flat positions and any desired raised positions.

The brake means of the backrest can be released by a patient lying on the bed by means of either one of a pair of lever control handles 31 disposed at opposite sides of the main frame adjacent the fixed section 1 6 of the mattress platform. The brake means of the knee-break are releasable by a lever control handle 32 which is situated near the foot of the bed so that it can only be operated by nursing staff.

Referring to the counter-balance means 27 and the brake means 29 of the knee-break, a bracket 33 is secured to one side of the main frame and has pivotally connected thereto one end of a gas spring 34 constituting the counter-balance means, the other end of the gas spring being pivotally connected to a strut 35, which is rigidly secured to the knee-break section 1 9. The gas spring has a constant tendency to extend in length thereby pushing on the strut 31 and urging the knee break sections to raised positions. The brake means 29 comprises a rod 36 extending through apertures in two plates 37 mounted in a housing 38 which is pivotally mounted on the main frame. The plates are spring-biassed away from one another into a position in which they are relatively inclined and frictionally engage the rod 36 to lock the knee break in position. The brake means is releasable by means of the control handle 32 which acts through a Bowden cable 39 to move the plates 37 towards one another against the action of the spring, thereby releasing the frictional engagement with the rod. The rod is therefore freely movable to allow the knee break to be raised or lowered.

Thus, to raise the knee break control handle 32 is operated to release the brake 29. The person operating the handle simultaneously pulls upwardly on one of the grab handles 26 to lift the knee break. This movement is assisted by the gas spring 34 and continues while sufficient force is being exerted and while the brake is held off by the control handle.

Referring to the counter-balance means 28 and the brake means 30 of the backrest, the counter-balance means, comprises a combined gas spring and compression spring 40 pivotally connected at one end to a bracket 41 secured to the main frame and at the other end to a strut 42 rigidly secured to the bracket section 1 7. The springs push on the strut to urge the backrest to a raised position.

The brake means comprises a rack housed in a casing 43 and a detent which is springbiassed into engagement with the rack to prevent movement of the strut 42 and hence to lock the backrest in position. The detent is releasable to enable the backrest to be raised or lowered by a Bowden cable 44 connected to two Bowden cables 45 operable by the responsive control handles 31.

Thus, to raise the backrest the patient operates one of the control handles 31 to release the brake 30 and pulls upwardly on one of the grab handles 25 to lift the backrest, this movement being assisted by the combined action of the gas spring and the coiled compression spring of the counter-balance means pushing on the strut 42.

When the backrest is to be lifted from the flat position fully loaded with a patient's weight, it will require substantial effort to start the lifting process but less effort to continue it as the angle of the backrest increases. This is because the point of action of the lifting force is shifting towards a vertical position above the articulated joint between the backrest 1 7 and the fixed section 16. The moment of the lifting force therefore reduces as the backrest is raised.

The coiled compression spring produces a maximum force at its most compressed condition, that is at the start of lifting of the backrest. In contrast, the gas spring produces substantially a constant force at any stage of extension. By using the heavy coiled compression spring, the size of gas spring required can be kept to a minimum and the counterbalancing effect is greatest when it is most needed, namely as the lifting process starts.

Even when a patient is lying on the bed, the counter-balancing force of the counter-balance means enables the backrest to be lifted relatively easily with little physical effort. The patient may have to lift his or her body slightly to enable the backrest to rise under the action of the counter-balance means.

The bed has a further control handle 46 connected by Bowden cables 47, 48 to the power means 1 4 to control descent of the bed.

The invention has been illustrated in connection with a Fowler type bed in which the mattress supporting sections are articulated relative to each other and in which the backrest and knee break sections are pivoted directly to the main frame. The invention could however be applied to the type of adjustable profile bed in which the backrest and knee break sections are supported on a linkage which is such that they operated simultaneously.

In the Fowler bed shown, the fixed mattress section 1 7 is optional. It has the advantage that a substantial part of the patient's body weight rests on this fixed section, rather than on the section 1 9 of the knee break or on the backrest 1 7. Thus, the counter-balancing forces required are kept to a minimum, enabling relative small gas springs to be used.

Although the invention has been described in relation to hospital beds, it could find use in other forms of bed, a couch or reclining chair, even for domestic use.

Claims (11)

1. A bed comprising a frame and a mattress platform having a number of articulated mattress supporting sections angularly movable with respect to each other and to the frame between a lowered position and a raised position, wherein at least one of the sections has associated therewith counter-balance means tending to assist in raising the section, brake means normally operative to hold the section in the lowered position and means operable to release the brake means to permit raising of the section.

2. A bed as claimed in Claim 1 wherein the counter-balance means comprises spring means.

3. A bed as claimed in Claim 2 wherein the counter balance means comprises a gas spring or a coiled compression spring or a combination of the two.

4. A bed as claimed in Claim 1, 2 or 3 which has three or four mattress supporting sections, one of which constitutes a backrest at the head end of the bed and two of which, adjacent the foot end of the bed, form a knee break, the counter-balance means being arranged to urge the backrest and/or the knee break to the raised position.

5. A bed as claimed in Claim 4 wherein the backrest section and knee break sections can be moved independently of each other, separate counter-balance means each with an associated brake means, being provided for the backrest and the knee break.

6. A bed as claimed in Claim 5 wherein release means for the brake means associated with the backrest are provided in a position accessible to a patient lying on the bed.

7. A bed as claimed in Claim 5 or Claim 6 wherein the release means for the brake means associated with the knee break are provided at a position inaccessible to a patient lying on the bed.

8. A bed as claimed in Claims 4, 5, 6 or 7 wherein the mattress platform has, in addition to the backrest section and the knee break sections, a fixed section between the backrest section and the adjacent knee break section.

9. A bed as claimed in any one of Claims 4 to 8 wherein means are provided for locating the knee break section adjacent the foot end of the bed in a horizontal position with the other knee break section in a raised, inclined position.

10. A bed as claimed in any one of the preceding claims wherein the release means comprises a handle connected by a Bowden cable to the brake means.

11. A bed substantially as herein described with reference to and as illustrated in the accompanying drawings.

1 2. Any novel feature or novel combina- tion of features disclosed herein and/or illustrated in the accompanying drawings.