This invention relates to a device for lifting a patient, particularly but not exclusively for lifting a patient from a seated location.

Current mobile patient hoists are powered by hydraulic hand-pumped pistons or by means of electrically powered linear actuators. Such devices suffer from various disadvantages. For example, they may be difficult to use by a person lacking the necessary strength and mobility to manoeuvre the hoist when loaded with the weight of a patient.

According to the present invention, a patient lifting device comprises:

a plurality of pneumatically inflatable bladders;

each bladder being confined within a container;

each container having a base, side members and a lifting member vertically displaceable between upper and lower positions and arranged to be moved from a lower position to an upper position as the bladder is inflated;

a pump;

a pneumatic conduit communicating between the pump and the bladders;

a pressure regulation valve; and

a plurality of hoist members, each extending from a respective lifting member, and having an attachment for engagement with a patient harness or support.

An assembly of two patient lifting bladders and containers may be arranged so that the distance between them is adjustable.

Use of the pneumatically inflatable lifting arrangement of this invention confers several advantages. An electrical power supply connected directly to the frame of the device is not essential. Gearing arrangements may not be necessary, reducing the complexity of construction and maintenance. The device of this invention is reliable, easy to repair and is not noisy in use.

The lifting device may comprise two inflatable bladders and containers, one located on either side of a patient's chair or mounted onto a floor-standing frame. The distance between the two bladder units may be adjusted to suit the size of a patient, for example, a bariatric patient, and also to facilitate lifting of a patient out of a wider chair than may be accomplished conveniently and comfortably using a conventional hoist.

Use of two or more pneumatic actuators allows infinitely variable adjustment of the height of each and may provide a self-levelling or self-balancing capability. Use of a pneumatic system has an advantage over a hydraulic system that a reservoir for hydraulic fluid is not necessary and leaks of hydraulic fluid are not possible.

In preferred embodiments, the pump is actuated manually, electrically or both.

The lifting member has a horizontal downward-facing surface arranged to engage an upper surface of a bladder in use.

In preferred embodiments, the bladder has parallel upper and lower surfaces connected by one or more expandable side portions, for example having a concertina construction with alternating hinged panels.

A sheet of low friction material may be provided between the bladder and container. The low friction material may comprise polymer coated paper or a polymeric sheet. The sheet may form an annular sleeve around the sides of the bladder and may be located between the sides of the bladder and an interior surface of the container in order to reduce friction and wear of the bladder material in use.

In a first particularly advantageous embodiment, the side members extend vertically from the base. Four side members may be employed. The lifting member may comprise a top plate having guide bosses arranged to receive the side members. Each guide boss may be made of a low friction material such as high density polyethylene or acetal resin.

The inflation tube and pressure relief valve may both be mounted on the base plate. The container side members are preferably vertically extending guides, for example, rods or grooved or ribbed formations. The lifting member may have a corresponding multiplicity of channels or slots to engage the rods.

Preferably each bladder is confined in a cage-like container having parallel vertically extending bars to constrain the movement of the bladder as it expands from a lower to an upper position or collapses in the opposite direction.

In a second particularly advantageous embodiment, the side members comprise arms of a scissor lift arrangement. Typically the side members may comprise pairs of arms, each pair of arms being connected by a pivotal linkage intermediate the ends of the arms, ends of the arms on a first side of the linkage being pivotally connected to the base and lifting member respectively and ends of the arms on a second side being slidably coupled to the lifting member and base respectively.

The pairs of arms may form an X-shaped configuration.

The bladder may comprise a rectangular airbag located between two pairs of arms. Such an arrangement has the advantage that the bladder is retained within the scissor lift arrangement, avoiding the need for use of vertically extending side members.

The inflation tube and pressure relief valve may both be mounted on the airbag top plate.

The pump may comprise a low pressure air compressor. Use of low pressure air to lift a patient eliminates a range of moving parts that would be required for a traditional electrically powered hoist. A sudden loss of pressure through failure of the compressor or a leak in one of the bladders or in the conduit system, may not afford a catastrophic movement of the patient as the reduction in height of the hoist may be limited to the maximum rate of air loss from either of the bladders or other part of the ystem.

In preferred embodiments, the device operates on both sides of a patient simultaneously and does not have any moving parts located in front of the patient. It can be used to simply lift a patient by a suitable amount off a chair and then allow the patient to be lowered back down onto a suitably designed commode pan or other chair, as desired, without the need to move the lifting device to another location. Therefore, the risk of the patient falling is considerably reduced, for example, following use of an incorrectly sized sling.

In preferred embodiments, the hoist members each have a pair of attachments so that the four straps of a range of commercially available slings may be used at the optimum position for safety and comfort of a patient. Use of a spreader bar, commonly deployed in front of a patient's face, may be avoided. Also, the fixing points may be wider, preventing crushing or compression of a patient's torso and legs during lifting. The lifting device of the present invention may be attached to either side of an existing chair frame using suitably desired catch plates or it may be mounted as a stand-alone device on a floor plate with brace bars fitted to maintain stability during the lifting process.

The invention is further described by means of example, but not in any limitative sense, with reference to the accompanying drawings, of which:-

Figure 1 shows a lifting device in accordance with the present invention;

Figure 2 shows a lifting device in accordance with the invention, not having a brace bar;

Figure 3 shows a chair-mounted version of a device in accordance with this invention;

Figure 4 shows the conduit arrangement;

Figure 5 shows the lifter arrangement in greater detail;

Figure 6 shows a close up of the carabiner bar of the device shown in Figure 5;

Figure 7 shows a detail of the lifting members;

Figure 8 is a further detail of the device;

Figure 9 shows successive stages in raising of the device;

Figure 10 further illustrates the bladder assembly;

Figure 1 1 illustrates an alternative embodiment including a scissor lift assembly; and

Figure 12 shows a further embodiment of the invention. Figure 1 shows a floor mounted stand-alone lifting assembly comprising two patient lifting devices. The assembly has two sides. The devices on the left hand side of the lifter frame (1) and on the right hand side of the lifter frame (2) are connected to a floor plate (4) by means of spring loaded safety catches or pins. These may be designed so that a specially shaped tool is required to access them to disengage the sides of the lifter from the floor plate. This serves to prevent accidental movement of the sides of the lifter when in use. A brace bar (3) extends between upper portions of the two frame members (1) and (2).

Figure 2 shows a similar assembly of two lifting devices not having a brace bar (3). The floor plate (4) is sufficiently rigid to avoid the need for additional bracing. Castors (30) enable each side of the frame to transported independently to and from the chosen location of the floor plate prior to mounting. In another embodiment the floor plate may have lockable castors fitted to it, to enable the device to be moved in either a loaded or unloaded condition. A conduit indicated generally at (31) is shown in more detail in Figure 4. A pump (not shown) is connected to an input conduit (13) communicating with a pressure relief valve (12). The pressure relief valve (12) may be a spring valve type connected to an air bladder (1 1) communicating with an inlet conduit (10). The inlet conduit (10) is connected by spring clips (9) to inlet control valves (8) of respective bladders (21) as shown in Figure 5.

Each bladder (21) is located within a chamber having a cage-like construction. The chamber has a lower portion (32) end portions (33) and two arrays of vertically extending parallel bars (20). A moveable plate (22) has slots arranged to allow slidable engagement with the bars (20) so that the plate (22) may be raised and lowered as the bladder (21) inflates or deflates.

A pair of vertically extending hoist members (19) have caps (18) which carry a carabiner bar (17). A pair of attachment carabiners or other attachment means (16) are fastened to the bar (17) to allow attachment to a harness (not shown). Shear pins (23) serve to prevent overloading of the apparatus during use. In a preferred example 8mm diameter 303 grade stainless steel pins are held in place by external circlips to prevent their unauthorised removal. Figure 7 shows how the lifter members (19) are supported during raising and lowering by support wheels (26). The wheels (26) reduce friction and assist with lifting. The wheels are mounted to the lifter top plate (24) and lifter middle plate (25). Each hoist member (19) is fitted at the base with shear pins (not shown) to prevent the hoist member (19) from coming out of contact with the support wheels (26) unless the operator presses and holds a spring loaded safety catch (27) in an open position while lifting the members (19) out of the lifter frame.

Figure 9 shows the device with the bladder in a fully deflated (a), half inflated (b) and fully inflated (c) positions. The safe working load and lift height can be varied by increasing or reducing the height of the lifter frame and the dimensions of the air bag clamp plate (not shown) to increase or decrease the area that the low pressure air acts on.

Figure 10 comprises two views of the bladder assembly. In Figure 10(a) the rectangular bladder is shown having vertically extending end walls (29) and side walls (30) and having an array of attachments (31) for securing to the upper and lower plates of the lifting arrangement in order to reduce uneven forces on the bladder in use.

Figure 1 1 shows a lifting arrangement comprising pairs of scissor lift arms (32,33) connected by a pivotal linkage (34) intermediate the ends of the arms to form an X-shaped configuration. First ends of the arms are connected by pivotal linkages (35,36) to the top plate (37) and base plate (38). Second ends of the arms are coupled to bars (39,40) mounted in horizontally extending slots (41,42) to accommodate lateral movements of the arms (32,33) as the scissor lift arrangement moves between upper and lower positions in use. Air inlet (43) is mounted in the base (38).

Figure 12 shows a further embodiment in which the bladder (44) is mounted on base plate (45) and is connected to movable plate (46). The movable plate (46) has guide bosses (47), preferably formed from low friction material such as high density polyethylene or acetal resin, to allow easy movement along guide bars (48). The air inlet (49) and pressure relief valve (50) are connected to the movable lifter plate (46) to minimise forces on the bladder (44) in use. In alternative embodiments (not shown) the pressure relief valve may be integral with the base plate (45).

Embodiments of this invention may incorporate vertically extending guide members together with a scissor lift arrangement. However, the use of vertically extending guide members may not be necessary, dependent on the materials from which the scissor lift arrangement is constructed.