WO1998020829A1

WO1998020829A1 - A suspension system, and a height-adjustable bed incorporating the suspension system

Info

Publication number: WO1998020829A1
Application number: PCT/AU1997/000767
Authority: WO
Inventors: Allan William Clarke; Barry Edward Mccrimmon
Original assignee: Gerontic & General Products Pty Ltd
Current assignee: Gerontic & General Products Pty Ltd
Priority date: 1996-11-12
Filing date: 1997-11-12
Publication date: 1998-05-22
Anticipated expiration: 1999-05-12
Also published as: AUPO356296A0

Abstract

A suspension means with particular application to a height-adjustable bed is disclosed. The bed comprises a substantially horizontal and generally elongate mattress platform (10, 11, 13) for supporting a mattress and a person. The bed also comprises a first bed end (41) at one end of the mattress platform and a second bed end (43) at the other end of the mattress platform, a means (31, 33, 37) for suspending the mattress platform from the bed ends, and a drive means (40) mounted on the first and/or the second bed end and adapted to move the mattress platform vertically within a predetermined range of vertical movement. The suspension means comprises a cluster of two sprocket wheels (33a, 33b) mounted at each end of the short end of the platform. The suspension means further comprises four drive chains (31a, 31b) for mating with the sprocket wheels (33a, 33b) whereby each drive chain is connected near a top corner of a bed end, from where it passes downward and under a nearest sprocket wheel (33a, 33b), across the short end of the platform, over the top of the mating sprocket wheel (33a, 33b) at the other end of the short end of the platform, and downward to a mounting point near the bottom of the bed end.

Description

A SUSPENSION SYSTEM, AND A HEIGHT-ADJUSTABLE BED INCORPORATING THE SUSPENSION SYSTEM

The present invention also relates to a height- adjustable bed incorporating the suspension system.

The present invention also relates to a suspension system that has particular application to a height adjustable bed and more general application to lifting devices.

Australian patent 639,124 in the name of D.F. rigley and F.S. Saberton discloses a height-adjustable bed that has a general application for use by handicapped and elderly people, and it is designed particularly for use in geriatric wards in hospitals and in nursing homes.

The bed disclosed in patent 639,124 comprises a pair of bed ends and a mattress platform which includes a frame supported on two beams . The mattress platform is suspended from the bed ends by a pair of chains associated with each beam. The chains pass over and under associated pairs of sprocket wheels mounted on the beams . The ends of the chains are connected to associated upper and lower mounting points on the bed ends. One of the pairs of sprocket wheels is fixedly mounted on a shaft which rotates with the sprocket wheels. A tension spring associated with one of the beams has one end connected to the beam and the other end connected to a wire which is wound around a fusee that is also mounted fixedly on the shaft . As the mattress platform is lowered, rotation of the shaft causes the wire to be wound on to the fusee, thus increasing the tension in the spring and providing a lifting bias for the mattress platform. An electric motor mounted on one of the bed ends preferably drives a screw and nut arrangement to raise and lower the mattress support platform.

The bed is a substantial improvement over beds that were in use or otherwise known before the priority date of 20 July 1990 of the patent.

Nevertheless, an object of the present invention is to provide a height-adjustable bed which is an improvement over the bed disclosed in patent 639,124.

A further object of the present invention is to provide an improved suspension system for lifting devices, such as height adjustable beds

According to the present invention there is provided a height-adjustable bed which, in use, comprises:

(a) a substantially horizontal and generally elongate mattress platform for supporting a mattress and a person;

(b) a first bed end at one end of the mattress platform and a second bed end at the other end of the mattress platform, each bed end being substantially vertical;

(c) a means for suspending the mattress platform from the bed ends; and

(d) a drive means mounted on the first and/or the second bed end and adapted to move the mattress platform vertically within a predetermined range of vertical movement.

It is preferred that the suspension means comprises a chain/sprocket assembly having sprocket wheels mounted to the mattress platform for rotation about axes parallel to a longitudinal axis of the mattress platform and chains extending between upper and lower mounting points on each bed end.

It is preferred particularly that the suspension means comprise :

(i) two spaced-apart pairs of sprocket wheels mounted to one end of the mattress platform, each sprocket wheel mounted for rotation about a horizontal axis that is parallel to the longitudinal axis of the mattress platform, and one sprocket wheel of each pair on one side of the mattress platform and the other sprocket wheel of each pair on the other side of the mattress platform;

(ii) two spaced-apart pairs of sprocket wheels mounted to the other end of the mattress platform, each sprocket wheel mounted for rotation about a horizontal axis that is parallel to the longitudinal axis of the mattress platform, and one sprocket wheel of each pair on one side of the mattress platform and the other sprocket wheel of each pair on the other side of the mattress platform;

(iii)a pair of first chains, each first chain having one end thereof attached to a respective upper mounting point on the first bed end, each of the first chains having its other end attached to a respective lower mounting point on the first bed end; one first chain passing under one and over the other of the sprocket wheels of one pair of sprocket wheels, the other first chain passing under one and over the other of the sprocket wheels on the other pair of sprocket wheels, the links of each first chain engaging with the teeth of its associated sprocket wheels;

(iv) a pair of second chains, each second chain having one end thereof attached to a respective upper mounting point on the second end, each of the second chains having its other end attached to a respective lower mounting point on the second bed end; one second chain passing under one and over the other of the sprocket wheels of one pair of sprocket wheels, the other second chain passing under one and over the other of the sprocket wheels on the other pair of sprocket wheels, the links of each second chain engaging with the teeth of its associated sprocket wheels; and

(v) a connecting member connecting together the sprocket wheels on one side of one end of the mattress platform and the sprocket wheels on the same side of the other end of the mattress platform so that rotation of the sprocket wheels is linked together.

It is preferred that the mattress platform comprises a back rest section that is mounted for pivoting movement about a horizontal transverse axis between a horizontal position and an inclined position so that the person in the bed may recline at a range of angles to the horizontal. It is preferred that the bed further comprises a means for raising and lowering the back rest.

It is preferred that the mattress platform be mounted for pivoting movement about a horizontal transverse axis at a head end of the bed between a horizontal position and an inclined position to place the person on the bed in a Trendelenberg position.

It is preferred that the bed further comprises a means for raising and lowering the mattress platform to the Trendelenberg position.

It is preferred particularly that the bed comprises a control means for enabling the person in the bed to actuate the means to raise or lower the mattress platform.

It is preferred that the bed comprises a guide means for enabling smooth vertical movement of the mattress platform when the drive means is actuated.

It is preferred that the guide means comprises a pair of spaced-apart vertical guide rails or posts mounted to each end of the bed.

In one arrangement, it is preferred that the guide means further comprises a plurality of guide members connected to the mattress platform and arranged to engage the guide rails to guide the mattress platform vertically when the drive means is actuated.

In another arrangement, it is preferred that the guide means further comprises a plurality of guide members detachably coupled to the mattress platform and arranged to engage the guide rails to guide the mattress platform vertically when the drive means is actuated. It is preferred that the guide members comprise pairs or combinations of rollers which are arranged so that the rollers of each pair or combination contact opposite sides of the rails or posts.

It is preferred that the bed further comprise a smoke detector system for automatically moving the mattress platform to a minimum height position in response to smoke detection.

According to the present invention there is also provided a suspension system for suspending a platform between two spaced-apart support members, which suspension system comprises:

(i) two spaced-apart pairs of sprocket wheels mounted to one end of the platform, each sprocket wheel mounted for rotation about a horizontal axis that is parallel to the longitudinal axis of the platform, and one sprocket wheel of each pair on one side of the platform and the other sprocket wheel of each pair on the other side of the platform;

(ii) two spaced-apart pairs of sprocket wheels mounted to the other end of the platform, each sprocket wheel mounted for rotation about a horizontal axis that is parallel to the longitudinal axis of the platform, and one sprocket wheel of each pair on one side of the platform and the other sprocket wheel of each pair on the other side of the platform;

(iii)a pair of first chains, each first chain having one end thereof attached to a - 1 -

respective upper mounting point on a first support member, each of the first chains having its other end attached to a respective lower mounting point on the support member; one first chain passing under one and over the other of the sprocket wheels of one pair of sprocket wheels, the other first chain passing under one and over the other of the sprocket wheels on the other pair of sprocket wheels, the links of each first chain engaging with the teeth of its associated sprocket wheels;

(iv) a pair of second chains, each second chain having one end thereof attached to a respective upper mounting point on the second support member, each of the second chains having its other end attached to a respective lower mounting point on the second support member; one second chain passing under one and over the other of the sprocket wheels of one pair of sprocket wheels, the other second chain passing under one and over the other of the sprocket wheels on the other pair of sprocket wheels, the links of each second chain engaging with the teeth of its associated sprocket wheels; and

(v) a connecting member connecting together the sprocket wheels on one side of one end of the platform and the sprocket wheels on the same side of the other end of the platform so that rotation of the sprocket wheels is linked together. It is preferred that the platform be a mattress platform and that the support members be bed ends .

The present invention is described further with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a preferred embodiment of a height adjustable bed formed in accordance with the present invention:

Figure 2 is a detailed perspective view of the head end of the bed with housing coverings removed and with the mattress support frame removed:

Figure 3 is a view on lines 3-3 on Figure 2 showing the guide mechanism;

Figure 4 is a view on lines 4-4 on Figure 2 and Figure 5 showing details of the bed end;

Figure 5 is a sectional plan view of the bed on the lines 5-5 on Figure 4;

Figure 6 is a view on lines 6-6 on Figure 5 of the bed end;

Figure 7 is a view similar to Figure 4 showing an alternative drive means for raising/lowering the mattress platform;

Figure 8 is a plan view showing the mattress platform;

Figure 9 is a side view on lines 9-9 on Figure 8 showing the means for raising/lowering the mattress support platform of the mattress platform; Figure 10 is a side view similar to Figure 9 showing the back rest of the mattress support platform in a raised position;

Figure 11 is a side view similar to Figure 10 showing the mattress support platform in a Trendelenberg position.

Figure 12 is a detailed perspective view similar to Figure 2 illustrating an alternative head end of the bed;

Figures 13a and 13b are side views of the mattress platform shown in Figure 8 showing raised and lowered positions of a support rail; and

Figure 14 is a detailed side view showing the correction of the support rail to the mattress platform.

The basic construction of the bed shown in the

Figures is similar in many respects to that of the preferred embodiment of the bed shown in Australian patent 639,124. In basic terms, the bed comprises:

(i) a mattress platform;

(ii) two bed ends at opposite ends of the mattress platform;

(iii)a means for suspending the mattress platform from the bed ends ; and

(iv) a drive means for raising and lowering the mattress platform.

With reference to the figures generally, the bed ends, namely a head end 41 and a base end 43, are formed from steel and each bed end comprises an end wall 47 and sides 49.

The mattress platform comprises:

(i) a support assembly of two spaced-apart elongate beams 11 and cross-members 13;

(ii) a mattress support frame 10 which rests on and is supported by the support assembly; and

(iii)a patient support rail 121.

The frame 10 and the support rail 121 are constructed from tubular steel and the beams 11 and the cross-members 13 are formed from C-section steel.

With reference to Figures 8-11, the frame 10 comprises two notched plates 111 at each end which are positioned so that the notches can receive outwardly extending pins 42 on the beams 11. The assemblies of the notched plates 111 and pins 42 form hinges which allow pivoting movement of the frame 10 with respect to the support assembly.

With further reference to Figures 8-11, in addition, the frame 10 is formed in two parts 12, 19 which are hinged together by hinge members 62, with the part 12 forming a back rest section which can be raised relative to the other part 19 from a horizontal position to a series of raised positions.

With reference to Figures 8, 13a, 13b, and 14, the side rail 121 is mounted on one side of the frame 10 so that a patient can easily move the side rail between a raised position shown in Figure 13a and a lowered position shown in Figure 13b.

The side rail 121 is mounted to the frame 10 by means of link members 123 pivotally connected at one end to the side rail 121 and at the other end to the frame 10.

The assembly further comprises stop pins 127 on the frame 10 which form rests for the link members 123 in the raised position. The frame connections of the link members 123 include elongated slots 125 which allow the link members to be lifted clear of the stop pins 127 and thereafter rotated clockwise to move the side rails 121 from the raised position to the lowered position.

The mattress platform further comprises a means for raising/lowering the back rest 12 and to raising/lowering the frame 10 into a Trendelenberg position shown in Figure 11 in which the legs and body of a person on the bed are raised relative to the head of the person.

With reference to Figures 8-11, the raising/lowering means comprises a dual acting piston/cylinder assembly having cylinders 81a, 81b and pistons 83a, 83b connected via pivoted forward and rearward link members 85a, 85b, 85c (85c of which is a double link member) to the back rest 12 and to a Trendelenberg support assembly, generally identified by the numeral 87.

The link member 85a is arranged to extend through a sleeve 91 that is mounted to a cross-member 93 for pivoting movement around the cross-member 93.

The Trendelenberg support assembly 87 comprises 2 parallel arms 95 each pivotally connected at one end to the part 19 of the frame 10 and at the other end to a sleeve 97 positioned on and rotatable around a cross-member 99 that is connected at opposite ends to the beams 11. The link member 85b is connected to a mid-point of the sleeve 97.

With reference to Figure 11, it can readily be appreciated that extension of piston 83a causes link member 85a to slide in sleeve 91 and this movement causes link member 85b and Trendelenberg support assembly 87 to rotate in a clockwise direction. As a consequence, the frame 10 rotates in a clockwise direction about the hinge assembly 111, 42 at the head end of the mattress platform and rises from the horizontal position shown in Figure 9 to the Trendelenberg position shown in Figure 11.

With reference to Figure 10, it can also be readily appreciated that extension of piston 83b causes anti-clockwise rotation of the double link member 85c and back rest 12. As a consequence, the back rest 12 is raised from the horizontal position shown in Figure 9 to the raised position shown in Figure 10.

The suspension system of the bed enables the mattress platform to be raised and lowered through a range of positions from the dashed outline lower position to the solid outline upper position shown in Figure 1. This range of movement of the mattress platform is a significant improvement over the height adjustment range of known height-adjustable beds in terms of the upper and the lower limits of the range and has wider application to lifting devices generally and not only to height-adjustable beds.

The preferred embodiment of the suspension system is based on the use of :

(i) 2 industrial strength chains 31a, 31b connected to each end of the bed; (ii) 2 pairs of spaced-apart sprocket wheels 33a, 33b mounted to each end of the mattress platform for rotation about axes that are parallel to the longitudinal axis of the mattress platform; and

(iii)2 connecting rods 37 that connect together the sprocket wheels 33a, 33b at one end of the bed and the sprocket wheels 33a, 33b at the other end of the bed.

With reference to Figures 2, 3, and 4, at the head end 41 of the bed, a chain 31a is attached to the head end 41 at an upper mounting point 35a on the left side of the head end 41 - as viewed in Figures 2 and 4. The chain 31a extends downwardly until it passes around the underside of a sprocket wheel 33a and then across the bed to a sprocket wheel 33a on the right side of the bed as shown in Figures 2 and 4. The chain 31a passes over the sprocket wheel 33a and then extends downwardly to a lower mounting point 35a on the head end 41.

Similarly, a chain 31b is attached to the head end 41 at an upper mounting point 35b on the right side of the bed as viewed in Figures 2 and 4. The chain 31b extends downwardly until it passes around the underside of a sprocket wheel 33b (Figure 5 only) and then across the bed to a sprocket wheel 33b (Figure 5 only) on the left side of the bed. The chain 31b passes over the sprocket wheel 33b and then extends downwardly to a lower mounting point 35b on the head end 41 on the left side of the bed as viewed in Figures 2 and 4.

With reference to Figures 5 and 6, there is a similar arrangement of pairs of chains 31a, 31b and pairs of sprocket wheels 33a, 33b at the base end 43 of the bed. With further reference to Figures 2, 4, 5 and 6, the sprocket wheels 33a, 33b on the same side at each end of the bed are fixedly mounted to a connecting rod 37 - only one of which is shown in the figures. Each connecting rod 37 extends through the channels defined by the beams 11 and is supported via bearings 51 (Figure 5) for rotation about its longitudinal axis . By this means , the sprocket wheels 33a, 33b are mounted to the mattress platform.

As can best be seen in Figure 5, each end of the connecting rod 37 shown in the Figure carries 2 sprocket wheels 33a, 33b. It can readily be appreciated that with this arrangement rotation of the sprocket wheels 33a, 33b at one end of the bed is transferred via the connecting rod 37 to the other end of the bed and rotates the sprocket wheels 33a, 33b at that end.

The above-described suspension system of the chains 31a, 31b sprocket wheels 33a, 33b, and connecting rods 37 completely supports the mattress platform relative to the bed ends 41, 43 and ensures that the mattress platform remains horizontal as it moves vertically upwardly and downwardly in response to operation of the drive means.

Furthermore, another advantage of the suspension system is that the sprocket wheels 33a, 33b can be disconnected easily from the chains 31a, 31b so that the bed can readily be broken down easily into separate components of the bed ends and mattress platform and conveniently packed and transported to an end location.

With reference to Figures 2 and 4, the drive means for moving the mattress platform comprises an electric motor 40 mounted on the head end 41 of the bed. The motor 40 drives a vertically-extending screw 45 which extends through and threadedly engages a nut 46 connected to cross-member 13 of the mattress platform. The lower end of the screw 45 is secured in a ball-race (not shown) in a bracket 99 which is mounted near the bottom of the head end 41. It can readily be appreciated that with this arrangement, rotation of the screw 45 about its vertical axis causes vertical movement of the mattress platform via the nut 46.

With reference to Figure 7, an alternative drive means for moving the mattress platform comprises a piston/cylinder assembly 103 mounted on the head end 41 of the bed with the piston 105 arranged to move vertically. The drive means further comprises a chain 107 which extends downwardly from a mounting point 109 on head end 41 and around the underside of a sprocket wheel 111 on the end of the piston 105. The chain 107 extends upwardly and then around a sprocket wheel 113 and downwardly to a mounting point 115 on the mattress platform. It can readily be appreciated that with this arrangement, downward/upward movement of the piston 105 causes the length of the chain loop around sprocket wheel 111 to increase/decrease and this has the effect of lowering/raising the mattress platform.

The bed further comprises a guide assembly at each bed end 41, 43 for ensuring smooth vertical movement of the mattress platform when the drive means is actuated.

With reference to Figures 2-6, the guide assembly comprises a vertical rail 61 connected to each side 49 of the bed ends 41, 43 and a guide carriage 63 connected to the ends of the elongate beams 11 of the support assembly of the mattress platform. The carriages 63 are constructed for sliding movement along the rails 61.

More particularly, each carriage 63 comprises a support plate 65 and pairs or combinations of rollers 67 extending from the support plate 65 and positioned so that the rollers 67 of each pair or combination contact opposite sides of the rails 61. It can readily be appreciated that which such an arrangement the mattress platform moves smoothly when raised and lowered by the drive means .

With reference to Figure 12, in an alternative embodiment of the present invention each guide assembly comprises :

(i) the components described in the preceding paragraph;

(ii) the cross -member 13 at the respective end of the bed;

(iii)a pair of sleeves 115 for receiving the elongate beams 11 of the support assembly of the mattress platform; and

(iv) a cross-member 117 for reinforcing the guide assembly.

This arrangement of the guide assemblies and the mattress platform makes it possible to readily break down the bed into the separate components of the bed ends 41, 43

(which carry the guide assemblies) and the mattress platform for transportation.

Figure 12 also illustrates a further feature which comprises tubular supports 119 for self-help and intravenous poles (not shown) .

Figures 5 and 6 also illustrate a preferred feature of the present invention which assists in the raising of the mattress platform. That feature is a tension spring and fusee arrangement. As shown in Figures 5 and 6, a tension spring 32 has one end secured to a mounting point 34 on one of the beams 11. The other end of the spring 32 is connected to a wire 35 which extends from the spring 32 around a roller 38 to a fusee 36 mounted on the connecting rod 37 extending through the other or the beams 11. As the mattress platform is raised or lowered, the fusee 36 rotates with the connecting rod 37. Specifically, as the mattress platform is lowered the consequential rotation of the connecting rod 37 causes the fusee 36 to rotate and to wind the wire 35 on to its scroll surface.

The tension in the spring 32 thus provides a force which acts against the lowering of the mattress platform and assists in the raising of the mattress platform when the rotation of the drive means is reversed.

The combination of the spring 32, the wire 35 and the fusee

36 thus provides, in effect, a form of counter- balance to the lowering of the mattress platform.

The above described bed has a number of considerable safety and performance advantages over conventional beds.

Many modifications may be made to the preferred embodiments of the present invention described above without departing from the spirit and scope of the present invention.

For example, whilst the preferred embodiments relate to a height-adjustable bed that is suitable for use by adults, it can readily be appreciated that the present invention is not restricted to this application and extends to height-adjustable beds in the form of cots that are suitable for babies and infants. Furthermore, whilst the preferred embodiments relate to a height-adjustable bed, it can readily be appreciated that the suspension system of the bed has wider application.

In the claims which follow and in the preceding description of the invention, the words "comprising" and "comprises" are used in the sense of the word "including", ie the features referred to in connection with these words may be associated with other features that are not expressly described.

Claims

CLAIMS :

1. A height-adjustable bed which, in use, comprises:

(c) a means for suspending the mattress platform from the bed ends; and

2. The bed defined in claim 1 wherein the suspension means comprises a chain/sprocket assembly having sprocket wheels mounted to the mattress platform for rotation about axes parallel to a longitudinal axis of the mattress platform and chains extending between upper and lower mounting points on each bed end.

3. The bed defined in claim 2 wherein the suspension means comprises:

4. The bed defined in any one of the preceding claims wherein the mattress platform comprises a back rest section that is mounted for pivoting movement about a horizontal transverse axis between a horizontal position and an inclined position so that the person in the bed may recline at a range of angles to the horizontal.

5. The bed defined in claim 4 further comprises a means for raising and lowering the back rest.

6. The bed defined in any one of the preceding claims wherein the mattress platform is mounted for pivoting movement about a horizontal transverse axis at a head end of the bed between a horizontal position and an inclined position to place the person on the bed in a

Trendelenberg position.

7. The bed defined in claim 6 comprises a means for raising and lowering the mattress platform to the Trendelenberg position.

8. The bed defined in claim 7 comprises a control means for enabling the person in the bed to actuate the means to raise or lower the mattress platform.

9. The bed defined in any one of the preceding claims comprises a guide means for enabling smooth vertical movement of the mattress platform when the drive means is actuated.

10. The bed defined in claim 9 wherein the guide means comprises a pair of spaced-apart vertical guide rails or posts mounted to each end of the bed.

11. The bed defined in claim 10 wherein the guide means further comprises a plurality of guide members connected to the mattress platform and arranged to engage the guide rails to guide the mattress platform vertically when the drive means is actuated.

12. The bed defined in claim 10 wherein the guide means further comprises a plurality of guide members detachably coupled to the mattress platform and arranged to engage the guide rails to guide the mattress platform vertically when the drive means is actuated.

13. The bed defined in any one of claims 10 to 12 wherein the guide members comprise pairs or combinations of rollers which are arranged so that the rollers of each pair or combination contact opposite sides of the rails or posts.

14. A suspension system for suspending a platform between two spaced-apart support members, which suspension system comprises :

(iii)a pair of first chains, each first chain having one end thereof attached to a respective upper mounting point on a first support member, each of the first chains having its other end attached to a respective lower mounting point on the support member; one first chain passing under one and over the other of the sprocket wheels of one pair of sprocket wheels, the other first chain passing under one and over the other of the sprocket wheels on the other pair of sprocket wheels, the links of each first chain engaging with the teeth of its associated sprocket wheels;

(v) a connecting member connecting together the sprocket wheels on one side of one end of the platform and the sprocket wheels on the same side of the other end of the platform so that rotation of the sprocket wheels is linked together.