GB2171597A - Overbed table - Google Patents

Abstract

An overbed table comprises a table-top (14) which is supported in cantilever fashion on the upper end of the outer member (18) of an upright telescopic post (12). The post (12) contains a lead screw and a nut thereon which is held stationary in the inner telescopic member (16) of the post so that rotation of the lead screw causes it to raise or lower the outer telescopic member (18) and, therefore, the height of the table-top. Rotation of the lead screw is effected by a handle (30) linked thereto by bevel gears acting as a step- up gear having a gear ratio in excess of 1:1 but not more than 1:3. In this way, the work of raising or lowering the table-top is made less tiring. <IMAGE>

Description

SPECIFICATION Overbed table This invention relates to an overbed table as used in hospitals.

Among the overbed tables available on the market are those which comprise a wheeled chassis having an upright telescopic post which supports a table-top at its upper end in cantilever fashion. The inner and outer members of the telescopic post are arranged for relative movement with respect to each other so that, by extending or retracting the post, the height of the table-top can be adjusted as required.

The present invention is concerned with that kind of overbed table where extension and retraction of the telescopic post is effected by a rotary handle which drives a lead screw or a nut thereon within the telescopic post. It is usual for the handle to have a shaft provided with a gear pinion on its inner end which engages a corresponding gearwheel on the upper end of the lead screw or on the nut with which the lead screw is engaged.

Hitherto the gear ratio between the pinion on the handle shaft and the gearwheel on the lead screw or its nut has always been 1 This means that the handle has to be rotated a large number of times in order to raise the table-top just a few centimetres.

This can be quite tiring for nursing staff and it is therefore an aim of the invention to reduce the amount of effort required.

According to the invention an overbed table comprises a vertically adjustable table-top which is supported in cantilever fashion on the upper end of a post containing a lead screw and a nut thereon of which one is rotatable by a handle to raise or lower the table-top, in which the handle drives the lead screw or the nut th rough a step-up gear having a gear ratio in excess of 1:1 but not more than 1:3.

Preferably the gear ratio of a step-up gear is substantially 1:1.5.

An example of an overbed table in accordance with the invention is shown in the accompanying drawing, in which: Figure lisa perspective view from above of the table; and Figure 2 is a diagrammatic perspective view of the drive for the lead screw in the telescopic post of the table, The overbed table shown in the drawing comprises a wheeled chassis 10 on which is supported an upright telescopic post 12 carrying, at its upper end, a table-top 14 in cantilever fashion.

The telescopic post comprises an inner member 16 and an outer member 18, the lower end portion of the inner member 16 being firmly secured to the chassis 10.

In orderto extend and retract the telescopic post 12, a lead screw 20 extends downwards inside the post for engagement in a stationary nut 22 which is attached in some way to the inside surface of the inner member 16. The upper end of the lead screw 20 carries a bevel gearwheel 24 which engages a bevel gear pinion 26 carried on the end of a drive shaft 28 provided on a handle 30, the handle being provided externally on the upper end of the telescopic post as shown in Figure 1.

Hitherto the ratio between the gear pinion 26 and the gearwheel 24 has always been 1:1. This means however that the handle 30 must be rotated many times to raise or lower the table-top 14 by just a few centimetres. Accordingly, in order to make this work less tiring, the gear pinion 26 and the gear wheel 24 form a step-up gear having a gear ratio in excess of 1:1 but not more than 3:1. Preferably the gear ratio is substantially 1:1.5.

1.An overbed table for use in hospitals and other such establishments comprising a verticallyadjustable table-top which is supported in cantilever fashion on the upper end of a post containing a lead screw and a nut thereon of which one is rotatable by a handle to raise or lower the table-top, in which the handle drives the lead screw or the nut through a step-up gear having a gear ratio in excess of 1:1 but not more than 1:3.

2. An overbed table according to claim 1, in which the gear ratio of the step-up gear is substantially 1:1.5.

3. An overbed table according to claim 1 or claim 2, in which the lead screw extends longitudinally of the post and is in screw-threaded engagement with a stationary nut which is attached to an inside surface of the post, the upper end of the lead screw being provided with a bevel gear wheel which engages a bevel gear pinion carried on a drive shaft rotated by the handle.

4. An overbed table according to any one of claims 1-3, in which the post is of telescopic form and comprises an inner member secured at its lower end to a wheeled chassis and an outer member which supports the table-top at its upper end.

5. An overbed table according to claim 4, in which the handle is mounted externally on the upper portion of the outer telescopic member of the post.

6. An overbed table substantially as described herein with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Overbed table This invention relates to an overbed table as used in hospitals. Among the overbed tables available on the market are those which comprise a wheeled chassis having an upright telescopic post which supports a table-top at its upper end in cantilever fashion. The inner and outer members of the telescopic post are arranged for relative movement with respect to each other so that, by extending or retracting the post, the height of the table-top can be adjusted as required. The present invention is concerned with that kind of overbed table where extension and retraction of the telescopic post is effected by a rotary handle which drives a lead screw or a nut thereon within the telescopic post. It is usual for the handle to have a shaft provided with a gear pinion on its inner end which engages a corresponding gearwheel on the upper end of the lead screw or on the nut with which the lead screw is engaged. Hitherto the gear ratio between the pinion on the handle shaft and the gearwheel on the lead screw or its nut has always been 1 This means that the handle has to be rotated a large number of times in order to raise the table-top just a few centimetres. This can be quite tiring for nursing staff and it is therefore an aim of the invention to reduce the amount of effort required. According to the invention an overbed table comprises a vertically adjustable table-top which is supported in cantilever fashion on the upper end of a post containing a lead screw and a nut thereon of which one is rotatable by a handle to raise or lower the table-top, in which the handle drives the lead screw or the nut th rough a step-up gear having a gear ratio in excess of 1:1 but not more than 1:3. Preferably the gear ratio of a step-up gear is substantially 1:1.5. An example of an overbed table in accordance with the invention is shown in the accompanying drawing, in which: Figure lisa perspective view from above of the table; and Figure 2 is a diagrammatic perspective view of the drive for the lead screw in the telescopic post of the table, The overbed table shown in the drawing comprises a wheeled chassis 10 on which is supported an upright telescopic post 12 carrying, at its upper end, a table-top 14 in cantilever fashion. The telescopic post comprises an inner member 16 and an outer member 18, the lower end portion of the inner member 16 being firmly secured to the chassis 10. In orderto extend and retract the telescopic post 12, a lead screw 20 extends downwards inside the post for engagement in a stationary nut 22 which is attached in some way to the inside surface of the inner member 16. The upper end of the lead screw 20 carries a bevel gearwheel 24 which engages a bevel gear pinion 26 carried on the end of a drive shaft 28 provided on a handle 30, the handle being provided externally on the upper end of the telescopic post as shown in Figure 1. Hitherto the ratio between the gear pinion 26 and the gearwheel 24 has always been 1:1. This means however that the handle 30 must be rotated many times to raise or lower the table-top 14 by just a few centimetres. Accordingly, in order to make this work less tiring, the gear pinion 26 and the gear wheel 24 form a step-up gear having a gear ratio in excess of 1:1 but not more than 3:1. Preferably the gear ratio is substantially 1:1.5. CLAIMS

1.An overbed table for use in hospitals and other such establishments comprising a verticallyadjustable table-top which is supported in cantilever fashion on the upper end of a post containing a lead screw and a nut thereon of which one is rotatable by a handle to raise or lower the table-top, in which the handle drives the lead screw or the nut through a step-up gear having a gear ratio in excess of 1:1 but not more than 1:3.

2. An overbed table according to claim 1, in which the gear ratio of the step-up gear is substantially 1:1.5.

3. An overbed table according to claim 1 or claim 2, in which the lead screw extends longitudinally of the post and is in screw-threaded engagement with a stationary nut which is attached to an inside surface of the post, the upper end of the lead screw being provided with a bevel gear wheel which engages a bevel gear pinion carried on a drive shaft rotated by the handle.

4. An overbed table according to any one of claims 1-3, in which the post is of telescopic form and comprises an inner member secured at its lower end to a wheeled chassis and an outer member which supports the table-top at its upper end.

5. An overbed table according to claim 4, in which the handle is mounted externally on the upper portion of the outer telescopic member of the post.

6. An overbed table substantially as described herein with reference to the accompanying drawing.