WO2001030295A1

WO2001030295A1 - Transfer system

Info

Publication number: WO2001030295A1
Application number: PCT/GB2000/003992
Authority: WO
Inventors: Philip Braithwaite
Original assignee: Traversall Limited
Priority date: 1999-10-22
Filing date: 2000-10-18
Publication date: 2001-05-03
Also published as: GB9924948D0; AU1035901A

Abstract

There is described a patient transfer system comprising a moveable belt supported on a patient platform which platform is mounted on the body of the transfer system characterised in that a first end of the moveable belt is attached to a first drive roller and a second end of the moveable belt is attached to a second drive roller. In order to transfer the patient more gently, a plurality of belts is used. Those belts are detachable at each end from the rollers. This facilitates ease of replacement of the belt.

Description

TRANSFER SYSTEM

This invention relates to a novel patient transfer system.

European Patent No 0 T47 986, Ledermann, describes a patient transfer trolley, provided with a roller driven endless belt and a series of drive wheels which are adapted to move the trolley towards the patient. Generally, the drive wheels will rotate at the same speed as the rotation of the belt. The roller driven endless belt is described in figure 5 of EP 0 147 986 and comprises a drive roller around which the endless belt is wrapped and a tension roller.

However, the Ledermann patient transfer system is bulky and complex in its mechanical structure, thereby being difficult and expensive to manufacture and maintain. Moreover, a significant disadvantage of the Ledermann transfer system and indeed other commercially available systems, is that, if the endless belt becomes worn or soiled then it is expensive and time consuming to replace.

Although other patient transfer systems are known they all generally suffer from the same disadvantages as the Ledermann system.

We have now found a novel form of patient transfer system which overcomes or mitigates the disadvantages of prior art systems.

In particular we have found the use of a dual roller mechanism in which there are two driven rollers which provide a wind in/wind out mechanism rather than the continuous belt of the prior art is especially advantageous and provides, inter alia, less wear on the belt and/or roller. Although the Ledermann prior art describes the use of two rollers the prior art transfer system comprises only one drive roller, the second roller being simply a tension roller. Thus according to the invention we provide a patient transfer system comprising a moveable belt supported on a patient platform which platform is mounted on the body of the transfer system characterised in that a first end of the moveable belt is attached to a first drive roller and a second end of the moveable belt is attached to a second drive roller.

The rollers are linked such that when one roller acts to 'wind in' the other roller acts to 'wind out' the belt. Thus it is possible that only one roller is driven by a drive motor at any one time and the other is left to freely rotate, for example, if one roller winds in the belt the other roller can freely rotate to wind out the belt. However, it is preferable that each roller will be driven by a motor at the same time. The rollers may be driven by a single motor but are preferentially driven by separate motors. Thus each of the ends of the belt should be attached to one of the rollers, that is, a first end is connected to a first roller and a second end connected to a second roller. Although it is conceivable that the rollers can act in opposite directions of rotation i.e. a first roller being moved clockwise and a second roller being moved anticlockwise, it is preferred that both rollers will move in the same direction of rotation.

Although a single belt may be used, we have found that smoother flow and therefore gentler transfer of the patient can be achieved if a plurality of belts is used, e.g. two belts. Furthermore, the use of a plurality of axial rollers mitigates the problem of the support bending around the middle due to the weight of the patient. It is a particular advantage of the invention that the belt is detachable at each end from the roller. This facilitates ease of replacement of the belt. A belt provided with roller attachment means is therefore novel per se and may be usefully supplied as a spare part.

Thus according to the invention we provide a belt for use in a patient transfer system as hereinbefore described which comprises a strip of belt material provided with a roller fastening means at each end of the belt. Any conventionally known fastening means may be used. However, a preferred fastening is a strip of hook and eye fabric e.g. Velcro (®). Thus, each end of the belt may be provided with a strip of Nelcro and each roller provided with a corresponding strip of Velcro upon which the belt Nelcro may be fastened.

The roller drive preferably comprises a simple electric motor. It is preferred that each roller has its own drive motor. Thus, both motors are preferably battery driven and the battery may, for example, be recharged overnight. The motors for the roller drive may be mounted in a variety of places but it is preferred that it is mounted at the base of one of the cantilevers which are situated at either end of the patient platform. It is preferred that the motor is distal from the patient access end of the platform helping to counterbalance the system and placing the weight above or substantially near to the load bearing portion of the platform.

In an especially preferred embodiment the belt is provided with a sensor or transducer which monitors the velocity of the belt.

Although the movement of the transfer system may be manually operated, in a further preferred embodiment of the invention the patient transfer system is provided with one or more motorised drive wheels. The platform support is provided with means of raising or lowering the drive wheel or wheels. Any conventionally known means can be utilised which may be mechanical or electromechanical. For example, a simple mechanical jack arrangement can be used, e.g. an integral jacking mechanism, which may comprise the drive wheels being operably linked to a substantially vertical worm screw. The use of the jacking mechanism provides a number of advantages. The transfer system may be provided with a plurality of castor wheels, such that, when the jack is lowered so that the drive wheel(s) is off the ground, the frame of the transfer system is supported on a plurality of wheel members, e.g. rotatably mounted castors. This enables the patient transfer system to be pushed from one place to another as if it were a conventional hospital bed. Alternatively, if the jacking mechanism is raised so that the drive wheel(s) is contacting the ground, then the transfer system can be moved towards or away from the bed of a patient to facilitate raising or lowering the patient. In a further advantage, when the drive wheel(s) contact the ground then the castors are raised slightly off the ground. Thus the transfer system and particularly the platform will tilt at a slight angle to the horizontal such that, in use, the end of the platform proximal to the patient will be lower than the opposing end. This is achieved by ensuring that the drive wheel(s) is situated away from the side that first contacts the patient. This is, in any case, advantageous since it aids access to the controls on the drive mechanism by an operator.

In an especially preferred embodiment the motorised drive wheels are also provided with a sensor or transducer which monitors the velocity of the drive wheels. In the most preferred embodiment the transfer system is provided with a first transducer which monitors the velocity of the drive wheels and a second transducer which monitors the velocity of one or more of the rollers. In such a system, the transducers may be operably linked to enable the velocity of the belt to be substantially the same as the velocity of the drive wheels. In particular we have advantageously developed an algorithm which enables the transducers and thereby the velocity of the drive wheels and the belt to be coincident.

Thus according to a further feature of the invention we provide a computer programme product adapted for data collection and the harmonisation of the motion of a transfer system as hereinbefore described. In particular the computer programme product is adapted to harmonise the velocity of the drive wheels and the belt.

The transfer system is preferably provided with a pair of load bearing drive wheels which are preferably situated centrally e.g. underneath the body of the transfer system. Whilst the castors may be situated near the drive wheels it is preferred that the load is spread and the castors are preferentially situated remote from the drive wheels. In an especially preferred embodiment the body of the system is provided with legs from which the castors are suspended. Each of the legs are substantially L- shaped such that the leg extending from the system body is coplanar with the longitudinal side of the platform. The system body is coplanar with the end portions of the platform. However, we have found it to be advantageous for the legs to be splayed, for example, the distal end of the leg is set at an angle of greater than 90° to the end of the leg proximal to the system body thus facilitating stacking of a plurality of the systems e.g. in a hospital environment.

The patient platform may comprise a rigid, e.g. metal, platform over which the belt can travel. Although any conventionally known platform structure could be used we prefer to use a lightweight frame. However, the frame is required to have sufficient rigidity and strength to take the weight of a large patient. Thus a preferred frame comprises an outer shell with an inner support framework, e.g. a honeycomb frame. By way of example only, such structures are known to be used in aeroplane design. Furthermore, the patient platform is preferably supported on one or more cantilevers to increase the strength of the patient platform without increasing the weight of the platform itself.

In order to render it lightweight the framework preferentially comprises a tubular steel structure. Furthermore, the transfer system may be provided with one or more guard rails to protect the patient and one or more push handles to move the transfer system. The system may also be provided with means to support various pieces of hospital equipment, such as oxygen cylinders, drip bags and tubes, medicaments, patient records, etc.

According to a further feature of the invention we also provide a method of transferring a patient which comprises lifting or lowering a patient onto or off a transfer system as hereinbefore described.

The invention will now be described by way of example only and with reference to the accompanying drawings, in which; figure 1 is a schematic representation of the patient transfer of the prior art; figure 2 is a vertical cross-section of the platform of the patient transfer system of the invention; figure 2a is an enlarged cross-section of the end portion of the belt and belt support; figure 3 is a cut away plan view of the transfer system of the invention; figure 4 is a vertical cross=section of the transfer system of the invention; figures 5 and 5 a are schematic representations of the drive wheels of the transfer system of the invention; figure 6 is a plan view of the transfer system without the belt shown; figure 7 is a side elevation of the transfer system without the belt shown; figures 8 and 9 show the transfer system of the invention in use; and figure 10 is the circuit diagram of the transfer system of the invention.

With reference to figure 1, the prior art transfer system comprises a continuous belt (PI), a drive roller (P2) and a tension roller (P3) and a belt support (P4).

With reference to figures 2 and 3, a patient transfer system (1) is provided with a first roller (2) and a second roller (3) and a fabric belt (4). The belt (4) is attached at its first end (5) to the first roller (2) and at its second end (6) to the second roller (3). The belt (4) wraps around and is supported by a patient support (7) . The patient support (7) is mounted on a cantilever (8) and comprises a metal honeycomb (9) mounted on a pultruded composite material (10) and covered with a stainless steel cover (11). The first roller (2) is also provided with a transducer (12).

Referring to figures 4 and 5, the cantilever (8) is mounted on the frame (13) of the transfer system (1). The frame (13) is provided with rotatably mounted castors (14) enabling movement of the transfer system e.g. from one bed to another. A drive wheel (15), and preferably a pair of drive wheels, are mounted about an axle (16) at the base (17) of the frame (13). The drive wheel (15) is powered by a motor (18). The axle (16) also engages with a pivot pin (19) enabling the vertical position of the axle (16) to be adjusted and hence raising or lowering the drive wheel (15) from the ground. The vertical adjustment mechanism is powered by a motor (20) connected to pivot pin (19) by a crank shaft (21). The drive wheel (15) is also provided with a transducer (22) which monitors the velocity of the drive wheel (15). When the drive wheel (15) is in the raised position the castor (14) contacts the ground. When the drive wheel (15) is in the lowered position the castor (14b) adjacent the drive wheel (15) will raise slightly off the ground. As the drive wheel (15) is lower than the castor (14b) the transfer system (1) will tilt slightly so that the distal edge (23) of the patient support (7) is lowered slightly, facilitating the transfer of a patient off or onto the belt (4).

Referring to figures 6 and 7, the patient transfer system (1) is provided with rollers (2 and 3) each of which is a composite comprising two rollers (2a, 2b, 3a and 3b). The use of the composite rollers mitigates the stress placed on the centre portions (2c and 3c) of the rollers (2 and 3). The rollers (2 and 3) are provided with separate drive motors (24a and 24b) and a control unit (25).

Referring to figures 8 and 9, in use, the patient transfer system (1) is positioned adjacent a bed (26). The drive wheel (15) is lowered raising the frame (13) and the adjacent castor (14b). The platform (7) is provided with a safety rail (27) which is raised manually. The drive wheel (15) moves the transfer system (1) towards the bed (26) and the patient support (7) slides underneath the patient (27). Once the patient (27) is fully on the support (7), the safety rail is lowered and the drive wheel (15) reversed. When the platform is fully away from the bed (26), the drive wheel (15) is raised and the adjacent castor (14) contacts the ground enabling the transfer system to be moved away.

Referring to figure 10, a flow diagram illustrates the algontium used in the software used in the system of the invention.

Claims

1. A patient transfer system comprising a moveable belt supported on a patient platform which platform is mounted on the body of the transfer system characterised in that a first end of the moveable belt is attached to a first drive roller and a second end of the moveable belt is attached to a second drive roller.

2. A patient transfer system according to Claim 1 wherein the rollers are linked such that when one roller acts to 'wind in' the other roller acts to 'wind out' the belt.

3. A patient transfer system according to Claim 1 wherein the drive rollers are driven by separate motors.

4. A patient transfer system according to Claim 1 wherein a plurality of belts is used.

5. A patient transfer system according to Claim 4 wherein two belts are used.

6. A patient transfer system according to Claim 1 wherein the belt is provided with a sensor or transducer which monitors the velocity of the belt.

7. A patient transfer system according to Claim 1 wherein the patient platform comprises an outer shell with an inner support framework.

8. A patient transfer system according to Claim 7 wherein the support framework comprises a honeycomb arrangement.

9. A patient transfer system according to Claim 1 wherein the system is provided with a drive wheel to move the system towards or away from the bed of a patient.

10. A patient transfer system according to Claim 9 wherein the system is provided with means of raising or lowering the drive wheel or wheels.

11. A patient transfer system according to Claim 9 wherein the drive wheel is provided with a sensor or transducer which monitors the velocity of the wheel.

12. A patient transfer system according to Claim 9 wherein a first transducer monitors the velocity of the drive wheels and a second transducer monitors the velocity of one or more of the rollers.

13. A patient transfer system according to Claim 1 wherein the belt drive comprises a pair of electric motors each of which is battery driven.

14. A patient transfer system according to Claim 1 wherein the system is provided with one or more of a guard rail; a handle; means for supporting an oxygen cylinder, drip bag and tubes, medicaments and patient records.

15. A belt for use in a patient transfer system according to claim 1 which comprises a strip of belt material provided with a roller fastening means at each end of the belt.

16. A belt according to Claim 1 wherein the fastening means is a strip of hook and eye fabric.

17. A patient transfer system according to Claim 1 wherein each end of the belt may be provided with a strip of hook or eye fabric and each roller provided with a corresponding strip of hook or eye fabric.

18. A computer programme product adapted for data collection and the harmonisation of the motion of a transfer system according to claim 1.

19. A method of transferring a patient which comprises lifting or lowering a patient onto or off a transfer system as hereinbefore described.

20. A patient transfer system substantially as described with reference to the accompanying drawings.

p36119.1