GB2521458A - Patient lifting apparatus and patient sling - Google Patents

Abstract

A patient hoist including a sling attachment member with one or attachment elements 22 and a load detection device attached to or associated with the attachment member. The hoist may have load detection elements positioned on first and second arms each with an attachment element 22. The load detection device may be a strain gauge or a load cell and may have a display which may include an alert is a load is below a threshold. The device may also identify if a load is balanced. A control means may be provided for adjusting the sling between a plurality of configurations. Also disclosed is a sling arrangement with a strain detection device attached to a hoist attachment member. A further disclosure relates to a hoist with an electrical connection arranged to be coupled to a sling with a load detection device.

Description

PATIENT LIFTING APPARATUS AND PATIENT SLING

The present invention relates to patient lifting apparatus, to a patient hoist and sling.

For sate operation, patient lifting hoists rely upon to the operator to attach and secure slings correctly to a lifting arm. Failure to ensure correct attachment of slings can result in the patient suffering discomfort, or being dropped and injured.

Typically there are two to three attachment points per side of the sling. For safe loading, all of these need to be attached to the lifting arm. Furthermore on some lifting hoists the load needs to be distributed appropriately between these attachment points to ensure safe and comfortable transfer of patient. The adjustment of this is a manual process and is very subjective.

The present invention seeks to provide a system and method of lifting a patient reliably. The preferred embodiments described herein are able to alert the operator as well as prevent a hoist being operated with inappropriately attached, loaded or secured slings.

According to an aspect of the present invention, there is provided a patient hoist including a patient sling attachment member provided with one or more attachment elements, and at least one load detection device attached to or associated with the attachment member.

In practice, the load detection device is arranged to detect a load placed on an attachment to the hoist, typically a patient support sling. The load detection device can therefore detect whether the hoist is in fact lifting the weight of a patient or whether the measured load is indicative of incorrect support of the patient, in which case the care staff can be alerted before causing the patient unnecessary discomfort or injury risk.

Preferably, the attachment member is a hoist arm, there being provided at least one load detection device positioned to detect load on the hoist arm.

Advantageously, the patient hoist includes at least one load detection device coupled to each of first and second ends of the hoist arm. With such an arrangement the apparatus is able to determine whether the patient is being supported by both sides (and/or ends) of a sling, for instance, and therefore whether such support is even and comfortable. A detection of uneven load bearing will be indicative of the patient support failing to support the patient evenly.

In a preferred embodiment, there is provided at least one load detection device positioned to detect load on one or more of the attachment elements. The attachment elements, which in some embodiments may be hooks or support rings, are likely to experience the most direct loading and are therefore suitable providing an accurate measure of load.

There may be provided at least first and second load detection devices positioned at first and second spaced attachment elements.

The load detection device or devices preferably include a strain gauge and/or load cell. It is preferred that load detection devices of the same type are used but it is not excluded that a combination of different types of load detection devices may be used. Strain gauges are simple, reliable, cheap and can easily be attached to or incorporated into load bearing elements of a hoist.

In the preferred embodiment, the patient hoist includes a user unit, which user unit is provided with a display device for displaying an indication of measured load. In its simplest form, the display device may just give a reading of measured load for verification by the care giver or clinician. In other embodiments, as described below, the user unit is more complex, including for instance a processing unit able to determine and generate data relating to detected and desired operating conditions of a load carrier, such as a sling, attached to the patient hoist. A more sophisticated unit can therefore provide additional assistance to the user, as will be apparent from the description which follows.

Advantageously, the or a user unit includes an alert device operable to generate an alert when detected load falls outside a given range. The alert device may be operable to generate an alert when the detected load is less than a given threshold, in other words when the patient is not being properly supported by the host. For this purpose, the given threshold is preferably generally equivalent to the load of a person's weight.

Advantageously, the user unit is operable to determine wherein the measured load is balanced across at least two load detection devices.

In a preferred embodiment of hoist apparatus, there is provided a sling adjustment mechanism co-operable with a patient sling for adjusting a patient sling. Such a mechanism is able to provide automated adjustment of a patient sling to ensure that a patient is properly and evenly supported via the hoist.

Advantageously, the adjustment mechanism includes at least one sling strap adjustment device.

In the preferred embodiments, the patient hoist includes a control unit coupled to the adjustment mechanism and operable to adjust a sling attached to the hoist so as to conform the sling to one of a plurality of patient holding configurations. The patient could thus be supported in a reclining position and moved to a sitting position, for example.

According to another aspect of the present invention, there is provided a patient sling including at least one hoist attachment member and at least one load detection device attached to or associated with the hoist attachment member.

In one embodiment, the hoist attachment member is a strap element, there being provided at least one load detection device positioned to detect load on the strap element. The sling may include a plurality of strap elements, there being provided a load detection device positioned to detect load on at least some of said strap elements. In an embodiment, there is provided a load detection device disposed at each strap element.

As with the hoist, the load detection device or devices could be or include a strain gauge and/or load cell.

For such a sling, there is preferably provided a patient hoist including one or more electrical connection elements arranged to be coupled to the one or more load detection devices of a patient sling. It is not excluded that the sling may include the load detection device or devices as well as data communication apparatus, such as an RF transmitter, in which case a standard hoist could be used yet benefiting from the advances taught herein.

The hoist could have any of the features disclosed herein.

Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a hoist assembly including a hoist arm according to the teachings herein; Figure 2 is a perspective view of an example of patient sling which may be used or configured according to the teachings herein; Figure 3 is an enlarged view of the cantilevered end of the hoist arm of Figure 1; Figure 4 is a view of the hoist arm of Figure 1 showing possible locations for load detection devices; Figure 5 is an enlarged view of the cantilevered end of the hoist arm of Figure 1 and of the straps and hooks of a sling, showing possible locations for load detection devices on the hoist and/or on the sling assembly; and Figure 6 is a schematic diagram of a control system of the hoist or sling taught herein.

Referring first to Figure 1, this shows in perspective view an example of mobile hoist assembly 10 used for lifting and moving a patient between first and second positions. For instance, a patient may be moved from a hospital bed or treatment trolley into a ward bed, wheelchair, bath or the like. The hoist assembly includes a lifting mechanism 12, which may or may not be power assisted and which couples to a hoist arm 14, described in further detail below. The hoist assembly 10 may be movable, in which case, it may be provided with castors 16.

In other examples, the hoist assembly 10 may be rotatably and/or pivotable with a substantially fixed base. The specific structure and design of the hoist assembly is not important to the teachings herein.

The hoist arm 14 incudes a proximal end 18, which couples to the lifting mechanism 12, and a cantilevered end 20, being the extremity of the hoist arm 14.

At each end 18, 20 of the hoist arm 14 there are provided attachment points 22, 24, respectively, to which a patient sling can be attached.

The hoist arm 14 is made of a strong and resilient material, typically of a metal tube, preferably having a gentle curve as shown in Figure 1.

Figure 2 shows in schematic form an example of a sling 30 used to support and lift a patient from one patient support to another. The sling 30, in this example, is formed of two sections, the first being a body section 32 shaped and sized to support patient's back and head, while a second, leg, section 34 is intended to support the patient's legs. The sling 30 is able to fold at the interface 36 between the first and second sections 32, 34. The sling 30 is also provided with a plurality of sets of straps 38-42, a first set being positioned towards the end of the body section 32, typically at the patient's shoulder height. A second set of straps 40 is positioned typically around the mid torso position of a patient and proximate the interface 36. A third set of straps 42 is located on the leg section 34 of the sling 30 and would support a patient's upper legs. The straps 38-42 can be single or double straps, double straps being depicted in Figure 2.

The straps 38-42 attach to the hoist arm 14 at respective attachments points 22, 24. Typically, the straps 38-42 are adjusted in length so as to support a patient held in the sling 30 in a desired configuration, for example lying, reclining or sitting. This can normally be achieved by having the straps 38, 42 longer than the straps 40. It will be appreciated that in some instances the sling 30 could be attached to a plurality of hoist arms such as a hoist arm 14 shown in Figure 1. It will also be appreciated that the sling 30 could be provided with more than three sets of straps 38-42 as desired and appropriate.

With reference now to Figure 3, this shows the distal end 20 of hoist arm 14 and in particular the attachment points 24. In this example, the attachment points 24 includes first and second support hoops 50, 52 extending from opposing sides of the hoist arm 14 and which in this example are divided by a central rod 54 to create two separate hooking points 56, 58 for supporting separate sling straps 38-42 as described below. The support loops 50, 52 are connected to the support arm 14 by a flange 16, which may be formed integrally with the support loops.

Typically, the support hoops 50, 52 and central rods 54 are made of metal and are integral with the support arm 14. In this example, as can be seen, support hoops 50, 52 extend in use substantially horizontally with respect to the support arm.

The straps 38-42 attach to the support hoops 50, 52 by a simple mechanism, in this example being by conventional hook element 64 attached at the extremities of the straps 38-42. Typically, the straps 38-42 on one side of the sling 30 will attach to one extremity 18, 20 of the support arm 14 and the other set of straps 38-42 on the other side of the sling are attached to the other arm end. It is preferred that each strap 38-42 is attached to a respective hooking point 56, 58 on one or the other of the support hoops 50, 52, such that each strap 38-42 is attached to an individual hooking point 56, 58.

It will be appreciated that other designs of hoist arms 14 could be provided with different designs of strap supports.

As explained above, when an incapacitated patient is to be moved from one location to another, the patient is placed on a sling 30, if not already lying on the sling 30. The straps 38-42 are then coupled to the respective hooking points 56-58 on the support arm 14, adjusted in length to make the patient comfortable, and then the hoist 10 operated to lift the patient from one support to another. As explained above, it is important that the patient is properly supported, that is that the straps are properly hooked onto the hoist assembly 10 and that they are of the right length to provide the required support. A strap which is too loose will not support a patient, making the patient uncomfortable when in the sling, with similar discomfort being experienced by a strap which is too short. Moreover, a strap which is not properly attached to the hoist arm 14 could cause the patient discomfort and even to fall out of the slingso.

Referring now to Figures 4 and 5, these show in schematic form modifications to the hoist assembly 10 and/or to a patient sling 30 in order to monitor correct and optimum attachment of a sling to the hoist assembly 10 and which in some embodiments is also able to adjust the configuration of a sling 30 to suit the particular requirements of the patient or caregiver.

In Figure 4, the hoist arm 14 is shown to have been provided with a plurality of load detection devices 70-74 attached to the support arm 14. The load detector and devices could be load cells or strain gauges. It will be appreciated that the load detection devices will include electrical leads extending therefrom, which would be held on the support arm 14 or located within the support arm 14, for coupling to a user unit, described in further detail below.

In its simplest form, the hoist arm 14 could be provided with a single load detection device 72 disposed substantially at its mid-point as shown in Figure 4. A load detection device disposed in this position is able to detect the strain imparted to the hoist arm 14 by a load carried in a sling 30. Only once a sling 30 is properly attached to the hoist arm 14 and is supporting the weight of a patient, will the support arm 14 flex, thereby causing load detection by the load detection device 72 (load cell or strain gauge in this example).

In another embodiment, the support arm 14 is provided with load detection devices only at its two ends 18, 20, namely the devices 70 and 74. These can likewise be attached to the support arm 42 and disposed in locations and in orientations at which the support arm 14 experiences strain when a loaded sling is correctly attached to the hoist arm 14. Other embodiments could provide all three load detection devices 70-74 as shown in Figure 4 or a different combination.

The actual position and orientation of such load detection devices 70-74 will be dependent upon the design and configuration of the hoist arm 14 and will be readily determinable by the person skilled in the art on the basis of the strain characteristics of the load arm.

Referring now to Figure 5, this shows the location of load detection devices for a number of other embodiments of the present invention. For example, load detection devices 80-84 could be provided on the support hoops 50, 52 and central rod 54 to detect strain on the support hoops and central rod when a fully loaded sling is attached to the hoist arm 14. Again, any combination of load detection devices 80-84 could be used, with some embodiments having only a single one of the load detection devices 80-84, whereas other embodiments may be provided two or more of the load detection devices 80-84, in whichever arrangement is deemed most appropriate.

In another embodiment, load detection devices 90-92 could be provided on the hook elements 64 attached to the straps 38-42 of a hoist 30, so as to detect strain of the hook elements 64.

In yet another embodiment, load detection devices 94-96 could be attached to or incorporated within the straps 38-42 themselves of a sling 30, thereby measuring directly the load carried by the straps 38-42.

In the embodiments of Figure 5, the load detection devices 80-96 could be of the types described above, that is load cells or strain gauges. It is to be appreciated also that in all of the embodiments disclosed herein, a combination of load cells and strain gauges could be used, in dependence upon the nature of the component used for detecting load and its location.

It will be appreciated that in the embodiments of Figure 5, equivalent load detection devices will be provided on the support hoop at the other side of the support arm 42 as well as for the equivalent straps at the other side of the sling 30.

Referring now to Figure 6, this shows in schematic form an example of control and user unit for the embodiments of hoist and sling disclosed herein. For the sake of clarity, the example in Figure 6 is shown for an embodiment of hoist arm provided with three load detection devices along the length of the arm. The control and user unit 100 includes a processing unit 102 able to process signals from the load detection devices, a user unit 104 providing load data to a user and, optionally, an input unit 106 for the purposes described below.

The processing unit 102 will typically include a microprocessor, suitable memory, one or more look up tables and so on, the components of which will be apparent to the person skilled in the art having regard to the teachings herein.

In its simplest form, the control system 100 is designed to alert an operator of the state of use of a patient sling 30, in one example to alert an operator when the hoist arm 14 is correctly supporting the weight of patient. In a more sophisticated embodiment, the system 100 is designed to prevent incorrect or inappropriate operation of the hoist assembly 10 and in particular to prevent such operation when it is determined that the hoist arm 14 is not supporting the weight of a patient.

The incorporation of load detection devices into the hoist assembly 10 and/or sling 30, whether by way of load cells or strain gauges, enables the system to identify whether the sling is properly loaded and hence correctly attached to the hoist arm 14 and in some embodiments to determine whether the sling 30 is loaded evenly and/or in accordance with expected loadings on the sling when a patient is properly held in the sling. The number of load detection devices used by the system 100 could be just one as it could be a plurality, for example up to six or more.

A load detection device 2 located at a centre point of the hoist arm 14, as depicted in Figure 6, can provide feedback to the user that the hoist and sling are carrying the weight of a patient. As a patient is lifted, the load detection device will provide feedback showing a rise in supported load. This rise will continue until a patient is fully supported within the sling, at which point the load recorded by the load detection device will remain constant. A constant reading is indicative of a patient having been fully lifted oft a support.

Embodiments which use a load detection device at either end 18, 20 of the hoist arm enable the system to provide feedback in effect on the left and right-hand sides of a patient within the sling. The two load cells can be used for providing comparisons relating to the left-hand and right-hand straps 38-42 of the sling 30, in order to indicate when the patient is not balanced within the sling 30 and thus to provide a warning to the user to adjust the sling or the patient. In an extreme circumstance, such an arrangement can also provide feedback as to whether or not one of the sides of the sling 30 is connected correctly to the lifting arm 14.

In a simpler version of this arrangement, the load detection devices may be positioned at the attachment point 22, 24 of the hoist arm 14 and arranged so as to take measurements from all of the left and all of the right hand sling connection points.

In a system providing a load detection devices for each individual attachment point (for instance by devices 80-84 as shown in Figure 5), it is possible to determine the loading status of the hoist in connection with the left and right hand side of a sling 30 as well as along the length of the sling 30, in particular the load carried by each strap 38-42 of a sling 30 or combination of straps 38-42 where two or more straps are coupled to a common attachment point on the hoist arm 14. In the embodiment of Figure 5, each strap 38-42 is connected to an individual attachment point 56, 58 on the hoist arm 14, thereby providing a total of six load signals, useful in indicating whether the patient is stable and conformable in the sling and evenly supported.

In connection with the above described examples, the hoist unit 102 in its simplest form feeds the load signals from the load detection devices to a user data unit 104 which may provide a display indicating load at each of the attachment points or a warning signal.

In other embodiments, the processing unit 102 is designed to provide a determination of measured load and in particular whether this meets a set threshold, which will then indicate to a user via the data user 104 whether the load is within an accepted range or above/below a cited threshold. For instance, the processing unit 102 can be arranged to provide a warning via the data unit 104 that a load detection device has failed to detect a load within an acceptable range indicative of a patient being properly supported by the hoist 14. A warning may be a visual, acoustic, vibratory signal or any combination of these.

The processing unit 102 can also be coupled to a hoist drive mechanism (not shown in the drawings) and coupled to prevent operation of the hoist drive mechanism if it is detected that upon raising of the hoist arm 14, the expected increase in load in the hoist arm 14 is not sensed. In this manner, the hoist assembly 10 cannot be operated to move the hoist arm 14 if the patient is not properly supported by the hoist.

The processing unit 102 may also control one or more sling adjustment devices, which may take the form of strap tensioners able to tighten or loosen the straps 38-42 of the sling 30. When the processing unit 102 determines from load feedback measurements from the load detection devices that one or more measurements does not fall within an expected range, the processing unit 102 will send command signals to the associated drive unit (not shown) coupled to the relevant strap or straps 38-42 to adjust the tension on the strap or straps and as a result the support given to the patient. Such adjustments can take place until the associated load detection device feeds back a load signal falling within the expected range.

The control unit 102 can therefore provide a self-adjusting tension system, thereby avoiding the need for a user to adjust the sling manually. In a specific example, such a self-adjusting tension system could include a tensioner and load detection device paired to a minimum of two positions (left to right) and up to six different positions in the example of sling of Figure 2.

It is also envisaged that the system 100 can be used to change the position of the patient automatically as a patient is lifted, for example from a lying position to a reclining or sitting position. The tensioner and load detection device pairings can be used for this purpose, in order to change the length of the straps 38-42, in this example, so as to move the panels or sections 32, 34 of the sling 30 from a substantially lying position to a sitting position and vice versa. For this purpose, the control system 100 may be provided with an input unit 106 which may include a number of pre-set position command inputs (for example switches), such that the configuration of the sling can be changed by a simple depression of one switch. In this regard, as a patient is lifted in the sling 30 and the control system determines that the patient's full weight is taken by the sling 30, the tension system can be operated to shorten the straps 38 and lengthen the straps 42 so as to move the patient from a lying position to a sitting position (or vice versa). In such a system, the care giver could place the patient in a seated position at the simple press of a button, for example.

One example of the process may be as follows: 1) care giver selects a "seated" position; 2) care giver positions sling and attaches itto the hoist arm 14, then begins to lift patient in a "laying" position; 3) once the hoist arm 14 is supporting the patient and knows what a balanced loading should be for the given patient, it can begin positioning the patient; 4) for the selected "seated" position, the tension system at the middle and head would begin to take more of the load by pulling the sling connections 38, 40 shorter; 5) the middle sling connections 40 would stop being altered while the head connections 38 would continue to be tightened; 6) the system 100 knows at all times that it is supporting the patient as the patient is initially lifted in the flat position to a balanced load.

The embodiments described herein can provide a number of advantages over the art, including but not limited to: a) removing the subjective nature of whether the patient is secure; b) removing the subjective nature of whether the patient is balanced; c) reducing the risks to the patient associated with misuse of the apparatus; d) reducing the risks to the care giver associated with misuse of the apparatus.

All optional and preferred features and modifications of the described embodiments and dependent claims are usable in all aspects of the invention taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another.

The disclosure in the abstract accompanying this application is incorporated herein by reference.

Claims (29)

1. CLAIMS1. A patient hoist including a patient sling attachment member provided with one or more attachment elements, and at least one load detection device attached to or associated with the attachment member.
2. 2. A patient hoist according to claim 1, wherein the attachment member is a hoist arm, there being provided at least one load detection device positioned to detect load on the hoist arm.
3. 3. A patient hoist according to claim 2, including at least one load detection device coupled to each of first and second ends of the hoist arm.
4. 4. A patient hoist according to claim 1, 2 or 3, wherein there is provided at least one load detection device positioned to detect load on one or more of the attachment elements.
5. 5. A patient hoist according to any preceding claim, including at least first and second load detection devices positioned at first and second spaced attachment elements.
6. 6. A patient hoist according to any preceding claim, wherein the load detection device or devices includes a strain gauge and/or load cell.
7. 7. A patient hoist according to any preceding claim, including a user unit, which user unit includes a display device for displaying an indication of measured load.
8. 8. A patient hoist according to any preceding claim, wherein the or a user unit includes an alert device operable to generate an alert when detected load falls outside a given range.
9. 9. A patient hoist according to claim 8, wherein the alert device is operable to generate an alert when the detected load is less than a given threshold.
10. 10. A patient hoist according to claim 9, wherein the given threshold is generally equivalent to the load of a person's weight.
11. 11. A patient hoist according to any one of claims 8 to 10, wherein the user unit is operable to determine when the measured load is balanced across at least two load detection devices.
12. 12. A patient hoist according to any preceding claim, including a sling adjustment mechanism co-operable with a patient sling for adjusting a patient sling.
13. 13. A patient hoist according to claim 12, wherein adjustment mechanism includes at least one sling strap adjustment device.
14. 14. A patient hoist according to claim 12 or 13, including a control unit coupled to the adjustment mechanism and operable to adjust a sling attached to the hoist so as to conform the sling to one of a plurality of patient supporting configurations.
15. 15. A patient sling including at least one hoist attachment member and at least one strain detection device attached to or associated with the hoist attachment member.
16. 16. A patient sling according to claim 15, wherein the hoist attachment member is a strap element, there being provided at least one load detection device positioned to detect load on the strap element.
17. 17. A patient sling according to claim 16, wherein the sling includes a plurality of straps elements, there being provided a strain detection device positioned to detect strain on at least some of said strap elements.
18. 18. A patient sling according to claim 17, including a load detection device disposed at each strap element.
19. 19. A patient sling according to any one of claim 15 to 18, wherein the load detection device or devices includes a strain gauge and/or load cell.
20. 20. A patient hoist including one or more electrical connection elements arranged to be coupled to the one or more load detection devices of a patient sling according to any one of claims 15 to 19.
21. 21. A patient hoist according to claim 20, including a user unit, which user unit includes a display device for displaying an indication of measured load.
22. 22. A patient hoist according to claim 21, wherein the user unit includes an alert device operable to generate an alert when detected load falls outside a given range.
23. 23. A patient hoist according to claim 22, wherein the alert device is operable to generate an alert when the detected load is less than a given threshold.
24. 24. A patient hoist according to claim 23, wherein the given threshold is generally equivalent to the load cause by a person's weight.
25. 25. A patient hoist according to claim 22, 23 or 24, wherein the user unit is operable to determine wherein the measured load is balanced across at least two load detection devices.
26. 26. A patient hoist according to any one of claims 20 to 25, including a sling adjustment mechanism co-operable with a patient sling for adjusting a patient sling.
27. 27. A patient hoist according to claim 26, wherein the adjustment mechanism includes at least one strap adjustment device.
28. 28. A patient hoist according to claim 27, wherein the adjustment mechanism includes a strap tightening and/or loosening device.
29. 29. A patient hoist according to claim 27 or 28, wherein the adjustment mechanism is operable to adjust a sling attached to the hoist so as to conform the sling to one of a plurality of patient holding configurations.