WO2022229623A1

WO2022229623A1 - Lifting apparatus

Info

Publication number: WO2022229623A1
Application number: PCT/GB2022/051052
Authority: WO
Inventors: Spencer Davis
Original assignee: Spencer Davis
Priority date: 2021-04-26
Filing date: 2022-04-26
Publication date: 2022-11-03

Abstract

A lifting apparatus (800), suitable for use inside a vehicle (10) such as an ambulance, particularly for transferring patients from wheelchairs (24) to stretchers (18) and vice-versa. The lifting apparatus (800) has a pair of beams (802) spanning the ceiling of the vehicle width-wise. A dolly (820) is mounted between the beams on rollers (822, 824). A winch system (840, 842) is provided on the dolly (820), which permits a patient to be lifted or lowered. The beams (802) and dolly (820) permit a patient suspended from the winch (840, 842) to be moved laterally within the vehicle (10). The dolly (820) is driven along the beams (802) by a lead screw (818) and motor (816) arrangement. The beams (802) have a minimal vertical dimension so as to reduce incursion into the headroom of the vehicle (10). One-sided servicing and repair is possible by an access panel from below. A backup hoist and/or locking means may be provided.

Description

LIFTING APARATUS

This invention relates to lifting devices, and in particular, but without limitation, to lifting devices suitable for use inside vehicles, such as ambulances.

Ambulance crews and paramedics are often required to undertake manual handling tasks, and in particular, transferring patients in to and out of wheelchairs and on to and off stretchers, etc., during their day-to-day activities. It is generally well-accepted that manually lifting the weight of a person either single-handed or in pairs can place unnecessary amounts of strain on the body and can thus lead to musculoskeletal injuries, which account for a great many days of lost work each year. It is estimated that, amongst the paramedic community, that thousands of work days are lost per year in the United Kingdom alone through manual handling-related injuries. It is therefore nowadays considered best practice to avoid manual handling and to use lifting aids, wherever possible.

For example, when lifting a person off the floor, it is possible to use an inflatable mat onto which a person can be rolled or placed when it is deflated, but which can be inflated to elevate the patient off the floor. Other devices include derrick-type winch systems that can be wheeled into position; and which have a motorised cable winch that can be used to assist with a lifting operation, for example when transferring a patient from a bed to a wheelchair - using a sling suspended from the winch hook. The problem with known lifting aids of the aforementioned types is the unreliability of their power supplies, which are generally battery-powered. Failure to maintain the batteries in an optimal charge state can render the lifting aid inoperative and/or lacking sufficient power at the point of use. Moreover, space constraints often prohibit or inhibit the use of these lifting devices, for example inside vehicles and in small rooms, etc.

One aspect of manual handling, which is currently very problematic, occurs when a paramedic crew needs to transfer a patient between stretchers or from a wheelchair to a stretcher inside a vehicle, such as when inside an ambulance. It is generally relatively easy to put a patient into a wheelchair initially and to wheel the patient in the wheelchair into the rear of the ambulance. A ramp is often provided at the entrance to the ambulance, up which the wheelchair, or a stretcher, can be rolled to position the patient inside the ambulance. In many cases, a winch can be used to drag a stretcher up the ramp - thereby avoiding the need for the paramedics to do so; and thereby reduce the manual handling requirements during such operations.

Flowever, once the patient sitting in the wheelchair is located inside the ambulance, it can be extremely difficult to then transfer them from the wheelchair onto a stretcher or bed for onward transportation and/or to carry out medical procedures. A further complication is that due to the forward-facing orientation of the wheelchair as it is wheeled up the ramp, versus the rearward-facing configuration of the in-ambulance stretcher/bed, the patient often needs to be turned around through 180 degrees during transfer from the wheelchair to the bed/stretcher.

The obstacle facing ambulance crews is a lack of space: the interior of an ambulance is generally quite cramped and there is often very limited floor space between the stretcher and seating/storage areas within which the ambulance crews are able to stand. Thus, when a wheelchair is placed in the walkway adjacent the stretcher, it is often very difficult, if not impossible, for a pair of ambulance crew members to be able to manoeuvre a patient from the wheelchair onto the stretcher because there is insufficient space at either side of the wheelchair to do so. This more often than not results in a single ambulance crew member having to transfer the patient single-handed, or an assisting ambulance crew member needing to position themselves awkwardly to be able to render assistance to the other one.

A further problem occurring when transferring a patient from a wheelchair to a stretcher is the difference in height between the seat of the wheelchair and the bed surface of the stretcher. This inevitably requires the patient to be elevated when transferring from the wheelchair to the stretcher and vice versa. In addition, there is the arm/wheel of the wheelchair to take into account, which normally projects above the level of the seat of the wheelchair and the bed/stretcher - thus requiring the patient to be lifted "up and over" the armrest/wheel of the wheelchair during transfer from the wheelchair to the stretcher and vice versa. In fact, this results in the patient needing to be at their most elevated position at the most awkward point of the transfer, namely when they are neither supported by the chair, nor by the stretcher; and when the ambulance crews are at "full reach" during the transfer procedure.

To ameliorate this, it is known to use a ceiling-hoist inside an ambulance or other vehicle to assist with manual handling operations. An example of such a ceiling hoist is disclosed in US20120060277A1 [Radzinsky, 15 March 2012], which discloses a pivoting support arm, which is secured to the roof inside the vehicle. The support arm extends radially outwardly from a central hub and thus has a generally part-circular range of movement, which permits transferring the patient across the width of the vehicle. A winch system is used with this device, which deploys a winch cable from the free end of the support arm - thus enabling a patient to be hoisted and transferred within the vehicle. A problem with this known arrangement is that it is mounted to the ceiling of the vehicle and therefore significantly reduces the headroom within the vehicle. This can easily lead to head injuries where the standing room within the vehicle is already limited. In addition, due to the fixed radius of the support arm, when transferring a patient from a wheelchair to the stretcher and vice versa, the locus of movement is arcuate - meaning that the patient swings about an arcuate locus, rather than being transferred linearly from the wheelchair to the stretcher and vice versa. This necessitates additional spare room within the vehicle to carry out the transfer operation, which can also be problematic. One solution to the aforesaid is described in GB2002713.2, which discloses an ambulance lifting device which uses a bight to permit lateral sliding of a patient along a track whilst maintaining their height/elevation.

Nevertheless, a problem that still arises, in particular in relation to lifting devices for use in vehicles, is the fact that if the vehicle is not parked perfectly level, there can be a tendency for the load supported on the track or lifting system to slide or move involuntarily within the vehicle. Additionally, if the vehicle is parked on a slant, moving a suspended patient from one side of the vehicle to the other, where this is an "uphill" direction, can be difficult, especially in the case of bariatric patients. Conversely, where the patient needs to be moved in a "downhill" direction, this can often be uncontrolled and result in excessive swinging of the patient when the lifting system hits its lower most end stop. To address this, GB2002713.2 proposes using a releasable lock to lock the position of the dolly relative to the track, but this only partially alleviates one or more of the above problems.

A need therefore clearly exists for a solution to one or more of the aforesaid problems.

Aspects of the invention are set forth in the appended independent claims. Preferred and/or optional features of the invention are set forth in the appended dependent claims.

According to one aspect of the invention, there is provided a lifting apparatus, suitable for use inside a vehicle, the lifting apparatus comprising: at least one track extending laterally across the ceiling of the vehicle; a dolly slideably mounted on the at least one track and thus being moveable laterally within the vehicle; a hoist suspended from the dolly connectable, in use, to a load to be lifted, lowered and transferred laterally within the vehicle; and a pulley arrangement operatively interconnecting the hoist to the dolly; wherein the pulley arrangement comprises: a cable having at least one cable portion which runs substantially parallel to the at least one track; and the dolly comprises at least two first fairings around which the said cable portion passes to form a bight below the dolly; a second fairing located within the bight to which the hoist is connected; the cable being connected to a winch such that retraction of the winch shortens the bight thereby raising the hoist or vice-versa, and wherein the position of the dolly relative to the track is adjustable by a drive means having a driving state in which the dolly is driven along the at least one track, and a static state in which movement of the dolly along the at least one track is inhibited or prevented.

The aforesaid configuration provides a lifting system whereby the distance between the hoist and the at least one track, for a given winch position, is independent of the lateral position of the dolly within the vehicle. This means that a load can be raised using the hoist and moved laterally within the vehicle without changing height. This is due to the configuration of the at least one cable portion which runs substantially parallel to the at least one track and the dolly comprising a set of fairings around which the cable portion passes to form a bight below the dolly: thus, movement of the dolly relative to the track allows the position of the bight relative to the track to be altered (laterally) without changing the length of the bight. However, hoist can be raised or lowered by adjusting the length of the bight, by using the winch. The arrangement thus provides independent control of the height of the hoist, and independent control of the lateral position of the dolly, and hence the load suspended from the lifting apparatus.

The drive means is suitably one which provides a combined driving and locking function. For example, a lead screw or worm gear arrangement acting between the track and the dolly could serve this purpose. Due to the high gear ratio of a worm gear or lead screw arrangement, when the worm or lead screw is not actively driven, it effectively locks the dolly in position on the track. However, rotation of the shaft/lead screw causes movement of the follower and hence the dolly along the track and, as a result of the high gear ratio, does not require an excessively powerful motor to do so - even if the vehicle is parked on a slant and/or a bariatric patient is being transferred.

Suitably, the drive means is detachably connected to the dolly. In a normal state, the drive means is connected to the dolly so as to permit the dolly to be driven along the track as needed. However, in the event of a power or other failure, being able to disconnect the drive means from the dolly can be useful, to provide manual, or hand operated override. Such detachment could be accomplished, for example, by providing a releasable clutch or clamp between the drive means and the dolly.

A further disadvantage of known lifting aids is a difficulty of installing them in a vehicle. They typically require extensive modification to the structural support system within the vehicle, such as the chassis, or installing dedicated support structures.

Weight is another disadvantage of known lifting aids because they are installed at ceiling height within the vehicle, they can excessively raise the centre of gravity of the vehicle. A need therefore exists for a lightweight lifting system, which the present invention aims to provide.

The overall dimensions of known lifting aids can also be disadvantageous because when they are installed at ceiling height, excessive vertical dimension can unacceptably reduce headroom within the vehicle.

However, by reducing the weight and/or vertical dimension of known liftings aid, their flexion under loading has been found to be excessive. Given that the SWL of most ambulatory lifting aids is specified at 4 metric tonnes, actually designing, and fabricating a lifting aid that is sufficiently light and "thin" to address the first two problems above has led to failing to address the flexion issue. There are thus competing design requirements, which the present invention aims address. A need therefore exists for a lightweight, compact yet sufficiently stiff lifting system, which the present invention aims to provide.

According to the present invention there is provided a lifting apparatus, suitable for use inside a vehicle, the lifting apparatus comprising: a pair of parallel C-beams, the parallel C-beams each comprising a substantially vertical web portion and substantially horizontal upper and lower return portions extending, respectively, from upper and lower edges of the vertical web portion, the parallel C-beams being arranged with their upper and lower return portions facing the upper and lower return portions of the opposite C-beam, such that the opposing lower return portions form a pair of parallel, spaced apart ledges that extend laterally across the ceiling of the vehicle; and a dolly located in the space between the parallel C-beams and having at least two rollers on either side of it that are supported by the parallel, spaced apart ledges, wherein a lifting winch is affixed to the dolly, which has a web or cable that can be extended or retracted from below the dolly to lower/raise, respectively, a load, and wherein the position of the dolly relative to the C-beams is adjustable by a lead screw running substantially parallel to the C-beams which is rotatable about its axis by a motor, and a lead screw follower fixed to the dolly that engages the lead screw, such that when the motor is driven to rotate the lead screw, the dolly is driven along the C-beams, but when the motor is static, movement of the dolly along the C-beams is inhibited or prevented by the gear ratio of the lead screw to the follower.

The C-beams are suitably manufactured from aluminium extrusions, which reduces the weight of the lifting apparatus compared with conventional steel-tracked lifting devices. However, excessive flexion of the aluminium beams is preferably reduced by the provision of elongate steel inserts affixed at each of the vertical web portion-horizontal upper/lower return portion junctions. This configuration has the advantage of providing a harder steel surface for the rollers of the dolly to run along, but also significantly increases the second moment of area, and hence the point loading lintel stiffness of the C-beams - without excessively increasing weight - by placing the steel reinforcement as far away as possible from the centreline of the C-beams.

Suitably, the vertical dimension of the substantially vertical web portion of each C-beam is less than about 150mm, and preferably less than 120mm. This maximises headroom within the vehicle.

Preferably, the dolly, the lifting winch, the lead screw, the motor and any associated wiring and control circuitry is located with an envelope defined by the overall length of the C-beams, their overall height, and by the distance between the outer surfaces of the C-beams. This configuration ensures that the lifting apparatus is as compact as possible.

When installed, it will be appreciated that the only access to the workings of the lifting apparatus will be from below, due to the location of the walls and ceiling of the vehicle against which the lifting apparatus is placed at either side and from above. Accordingly, a removable cover plate is suitably provided which spans the substantially horizontal lower return portions of the C-beams thereby forming an enclosure for the mechanism of the lifting apparatus. The removable cover plate may be formed from a pair of spaced apart sheets, leaving a gap or slot therebetween for the lifting web or cable to emerge from; or it may be a single cover plate with an elongate slot cut into through which the lifting web or cable emerges.

Due to the necessity of sanitising the interiors of certain vehicles, such as ambulances, using fogging technology, the electronics of the lifting apparatus are preferably IP-rated against the ingress of airborne particles and liquid droplets of the 1-lOum range. This can be accomplished by using chemical-resistant cabling, hermetic seals, and cable glands.

Preferably, the lifting winch comprises an override clutch, which permits a load suspended thereby to be lowered in a controlled manner independently of the winch motor. This is an important failsafe for in the event of a power or control failure, such that a person suspended from the winch can always be lowered even if power and/or control of the lifting apparatus is lost.

Additionally or alternatively, the dolly may comprise a fixing point, such as an eye, or a socket to which an eye can be connected, such that in the event of a power and/or control failure, a supplementary, e.g., a manually pulley system, can be used to take-over the operation of the lifting winch.

In order to further protect users and operators of the lifting system, electronic end stop switches are preferably provided to limit the extent of movement of the dolly relative to the track, as well as the retraction/extension of the lifting winch. Preferably, the limit switches are normally closed limit switches that are wired in series, such that in the event of failure of any one of the limit switches, the entire lifting system will cease to function.

The present invention, therefore, proposes a lifting unit, which can simply be bolted in position within the vehicle without having to add additional structure to the vehicle itself. To accomplish this, the present invention proposes, in certain embodiments, to have opposite ends of the track affixed to brackets, which in turn affix to legs or upstands. The lower ends of the legs simply need a flange member into which the lower ends of the uprights/legs are located, which flange members can be bolted down to the floor of the vehicle. By providing such a structure, it is possible to have a unitary, inverted U frame which provides all of the necessary weight bearing capability, stabilisation mechanism and fixing - all without requiring excessive modification to the vehicle.

In a preferred embodiment of the invention, the supporting structure for the lifting device has a maximum "thickness" of approximately 50 millimetres. This limitation usefully enables the supporting structure to be fitted between the outer skin and the inner skin of a conventional vehicle (and in particular, an ambulance) and this is particularly advantageous from an aesthetic point of view; but also, from a cross-infection control perspective. By concealing the device between the two skins of the vehicle, save for a slot through which the dolly/hoist protrudes, it is possible to effectively conceal the lifting device in an aesthetically pleasing manner whilst also facilitating wipe down/cleaning of the interior of the vehicle. Locating the lifting device between the two skins of the vehicle additionally provides the advantage of removing head impact collisions/finger trap points, etc., as well as not impinging on the existing headroom within the vehicle.

The ceiling track system comprises at least one track that extends laterally across the ceiling of the vehicle. However, a pair of parallel tracks are preferred as this can serve to better retain and/or stabilise the dolly. The ceiling track system can be affixed to the ceiling of the vehicle by any suitable means, such as by using bolts and nuts, rivets etc. Spacers may optionally be interposed between the track or tracks and the underside of the ceiling, for example, to obtain a desired track height above the floor and/or to accommodate the shape of non-planar ceiling surfaces.

The dolly is slideably mounted on the C-beams and can thus be moved laterally within the vehicle. This enables a suspended load to be moved from left-right or vice versa within a vehicle, such as to transfer a patient from a wheelchair to a bed and vice versa. The word "laterally" in the context of the present invention is to be construed as meaning permitting movement of a load from towards one side of the vehicle to the other (optionally, but preferably crossing the vehicle's midline in the process), although such movement does not necessarily have to be at right angles to the midline of the vehicle.

Additional locking means may be provided for locking the position of the dolly on the track at one or more pre-set positions. Suitable locking means may comprise one or more detents on the track into which sprung ball bearings of the dolly engage at one or more positions. Additionally or alternatively, a braking or latching system may be provided to secure the dolly at one or more given positions, which braking or latching system preferably requires user intervention (such as pressing a button or lever) to disengage.

Preferred embodiments in the invention shall now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic cross-sectional side view of a known ambulance;

Figure 2 is a schematic cross-sectional side view of an ambulance fitted with a lifting device according to one aspect of the invention;

Figure 3 is a schematic cross-sectional plan view of the ambulance shown in Figure 2;

Figure 4 is a schematic, perspective view of a lifting device in accordance with a lifting device according to one aspect of the invention ; Figures 5 and 6 are schematic, perspective views of the lifting device of Figure 4 in different configurations;

Figure 7 is a schematic, perspective view of a known alternative embodiment of a lifting device according to one aspect of the invention; and Figure 8 is a schematic, perspective view of a known support frame for a lifting device according to one aspect of the invention;

Figure 9 is a perspective view of part of a lifting device in accordance with the invention;

Figure 10 is a plan view from above of the lifting device of Figure 9;

Figure 11 is a partial perspective view of a lifting device in accordance with the invention, per Figures 9 and 10;

Figure 12 is a schematic perspective view of a lifting device in accordance with the invention;

Figure 13 is a close-up detail view of the lifting device of the invention;

Figure 14 is a perspective top view of the lifting device of the invention; and

Figure 15 is a front perspective view of a lifting apparatus in accordance with a second aspect of the invention;

Figure 16 is a left-end perspective view of a lifting apparatus in accordance with the second aspect of the invention;

Figure 17 is a right-end perspective view of a lifting apparatus in accordance with the second aspect of the invention; Figure 18 is a plan view of the right end of the lifting apparatus of Figure 15;

Figure 19 is a perspective view of the right end of the lifting apparatus of Figure 18;

Figure 20 is an internal perspective view of the dolly;

Figure 21 is a plan view of the dolly; and

Figure 22 is a perspective view of the left end of the lifting apparatus of Figure 15. Referring now to Figure 1 of the drawings, a known ambulance 10 is shown schematically inside cross-section and comprises a driver's cab 12 and a saloon cabin 14 mounted on a chassis 16. Inside the saloon cabin 14, there is a bed or stretcher 18 and access to the interior of the saloon cabin 14 is gained via an entrance 20 at the back of the ambulance 10. A ramp 22 can be used to bring a patient on a wheelchair 24 or stretcher 241 into the ambulance 10 by pushing or pulling the wheelchair 24 up the ramp so that the wheelchair 24 is raised from the floor surface 26 to the floor level 28 within the saloon cabin 14 of the ambulance 10.

As it can often be a difficult job to push a stretcher 241 up the ramp 22, a winch 30 is often used, which is permanently wired into the ambulance 10. The winch comprises a winch cable 32, which is typically a "seatbelt webbing" type cable, which connects to the stretcher 241 using a carabiner or a seatbelt type connector 34. By retracting the winch 30, the stretcher 241 can be pulled up the ramp 22 and into the saloon cabin 14 of the ambulance as shown by the solid and dashed lines in Figure 1. In some cases, the winch is misused to drag a wheelchair 24 up the ramp 22, but this is often contraindicated due to the flimsiness of the lightweight wheelchairs 24 that ambulance crews tend to carry.

Once the wheelchair 24 is inside the ambulance 10, it is often necessary to transfer a patient seated in the wheelchair 24 from the wheelchair 24 onto the bed 18 (or in some cases, onto a seat- belted seat (not shown) within the ambulance 10. As can be seen, the height of the seat 36 of the wheelchair 24 is generally lower than the height of the bed surface 38 of the bed 18 (or the seat-belted seat), and this therefore requires the patient to be lifted out of the wheelchair 24, up and over the armrest/wheel and then lowered down onto the surface 38 of the bed 18. Within the confines of a cramped ambulance saloon cabin 14, this can be very difficult for the reasons previously explained.

Referring now to Figures 2 and 3 of the drawings, a lifting device 100 in accordance with the invention has been fitted to the ambulance 10.

The lifting device 100 comprises a lateral track 102, which is formed, in the illustrated embodiment, by a pair of parallel tracks running at approximately 90 degrees to the midline of the ambulance 10 - across the width of the vehicle from side to side. A dolly 104 is suspended from the tracks 102 and a hoisting hook 106 hangs below the dolly 104. The existing winch strop 32 connects, via a connector 108, to a cable system 110 of the lifting device 100. The cable 110 extends up to the roof of the vehicle 14 and passes around a pulley 112 and then extends rearward before passing around a further pulley 114 and then across the width of the vehicle to a termination point 116. The cable 110 passes over pulleys 118 on the dolly 104 and hangs down below the dolly 104 to form a bight 120. A further pulley 122 is located within the bight 120, from which the suspension hook 106 depends. By retracting the winch 30, the cable 110 is pulled down as indicated by arrow 124, which shortens the bight 120 and thereby raising the hook 106. Meanwhile, the dolly 104 can be moved from left to right within the vehicle, as indicated by arrow 126.

The overall arrangement can be seen three-dimensionally in Figures 4, 5 and 6 of the drawings, although one of the tracks 102 has been omitted for clarity in those drawings. As can be seen, the dolly 104 has a set of rollers 128, which roll within a track part 130 of the tracks 102 and thus enable the dolly 104 to be slid from left to right 126 within the vehicle. It will be appreciated that as the dolly 104 moves (as indicated by arrow 126), the portion of the cable 1102 on one side of the dolly 104 shortens or lengthens, whereas the length of the cable 1104 on the opposite side of the dolly 104 lengthens or shortens, respectively. This means that no matter the position of the dolly 104, the length of the bight 120 remains the same. This is shown, schematically, in Figure 5 of the drawings where the winch strop 32 is retracted 132 by the winch 30 causing the effective length of the cable 110 to be shortened and thereby shortening the length of the bight 120 by half that amount 134. Another advantage of the bight 120 arrangement is that it provides a mechanical advantage (it doubles the lifting force) at the hook 106 - meaning that the winch 30 can easily be re-purposed as a hoisting device, rather than a dragging device.

As can be seen from Figure 6 of the drawings, regardless of the position of the dolly 104 on the track 102, the elevation 136 of the hook 106 remains unchanged - for a given position of the connector 108.

It will also be seen, from Figures 4, 5 and 6 that the connector 108 is a seatbelt type connector, which enables it to readily connect to a complementary buckle 1082 at the end of the winch strop 32.

Referring to Figure 7 of the drawings, a different embodiment of the invention is shown, although functionally equivalent elements are indicated by identical reference signs for ease of cross- referencing. In this case, the aforedescribed cable has been replaced by a webbing type strop, although this is not drawn to scale in Figure 7. In this case, the webbing strop 110 is formed as a continuous loop and a carabiner 150 is used to connect the webbing strop 110 to a secondary cable 1106, which, in turn, connects to the winch (not shown). Flere, it can be seen that the afore-described pulleys have been replaced by rollers 152, but the overall functionality of the system is basically the same.

The configuration shown in Figure 7 of the drawings has the advantage over that shown in Figures 4-6 of the drawings of additional mechanical advantage, as well as having a shorter lengthwise dimension within the vehicle 10. The pulling force 1320 can be resolved into lengthwise 1322 and width wise 1324 components depending on the angle 1326 of the webbing strop 110 relative to the direction of pull 1320. This results in a higher width wise 1324 component - thereby amplifying the force of the winch. In addition, there is the 2:1 mechanical advantage afforded by the bight 120, and that means that the power of the winch is easily ample for use as a lifting device.

Although not shown in the drawings specifically, the suspension hook 106 suitably comprises a swivel to permit a patient, suspended therefrom, to be rotated to align with an intended direction, e.g., forward-facing, side-facing or rearward-facing - as the case may be.

Finally, Figure 8 of the drawings shows how the lifting device can be installed in a vehicle using a dedicated support frame 200, that obviates the need to connect the system 100 to the roof of the vehicle 100 directly. The support frame 200 comprises a set of upright tubes 202 with mounting feet 204 at their bases for connection to the floor/sub-frame/chassis of a vehicle (not shown). A set of lateral tubes 206 span the tops of the upright tubes 202, and a longitudinal tube 208 extends between the lateral tubes 206. Towards the front of the support frame 200, i.e., at the bulkhead end thereof, an additional upright tube 210 is provided that aligns with the position of the winch 30 within the vehicle. The additional upright tube 210 resists bending of the forward lateral tube 206 under the force of tension in the vertical part of the winch cable/strop (not shown), whereas the longitudinal tube 208 resists bending of the forward and rearwards lateral tubes 206 towards each other under the tension of the cable. The rearward lateral tube 206 supports the lifting device (not shown for clarity). It can be appreciated that the support frame 200 can be located securely within the vehicle and avoids the need for any weight- or force-bearing components of the lifting device to be connected to any non-structural parts of the vehicle.

Referring now to Figures 9 to 14 of the drawings, an embodiment of the invention is shown. A lifting device 500 in accordance with the invention comprises, in a manner similar to that previously described, a track 102, which extends laterally across the width of a vehicle (not shown), which, in the illustrated embodiment, is a generally C-shaped cross-section extrusion. By using a generally C-shaped extrusion, a slot 502 is formed, through which a lifting point 106 can protrude, with the remainder of the dolly and/or mechanism located within the cross-tube/track 102. As can be seen from Figure 9 and Figure 10, the dolly 104 comprises two pairs of rollers 128 that are mounted on respective axles 504, with a pulley wheel 118 interposed therebetween. The axles 504 are maintained at a fixed separation by apertured plates 506, such that the axles 504 move in unison along the interior of the generally C-shaped track 102.

A wire 110 passes around the pulley wheels 118 so as to form a bight 20, with a further pulley wheel 122 located within the bight 120. The further pulley wheel 122 is also mounted on an axle 506, from which the hoisting point 106 depends.

As can be seen, in particular, from Figure 11 of the drawings, one end of the cable 110 is fixed 510 at one end, whereas the other end of the cable 110 is connected to a winch 30. By rotating the winch motor in one direction or the other, effective length of the cable 110 can be increased or decreased, thus causing the lifting point 106 to move up and down, as indicated by arrow 134. Due to the bight 120, the dolly arrangement 104 is able to move along the track 102 as indicated by arrow 126 without altering the height of the lifting point 106 for a given cable length.

The dolly arrangement 104 is, however, constrained in its movement 126 along the track 102 by virtue of a threaded rod 520, which is supported at one end by a bearing 522, and which is connected, at its other end, to a drive motor 524. The threaded rod 520 passes through a complementarily threaded ferrule 526, which is connected to the linking plates 506 by an extension plate 528. It will be readily apparent to the skilled reader that rotation of the motor 524 causes the threaded rod 520 to rotate about its axis, thereby causing the ferrule 526 to screw/move 126 along parallel to the axis of the rod 520. The dolly 104 can thus be moved 126 in either direction along the track 102 by rotating the motor 524 in one direction or the other. Furthermore, because of the high gear ratio between the threaded rod 520 and the ferrule 526, unless the motor 524 is actively driven by the motor, it is virtually impossible to move the dolly 102 along the track due to the high gear ratio between the threaded rod 520 and the ferrule 526. This effectively locks the dolly 102 in position depending on where the motor 524 is started and stopped.

Referring now to Figures 12, 13 and 14 of the drawings, the physical arrangement of the lifting device 500 is shown in greater detail. Flere, it can be seen that the lateral track 102 encloses the dolly within it - with just the hoist 106 protruding, when the lifting point 106 has been moved to its uppermost position. At either end of the track, there are a set of right-angled brackets, into which are affixed the upper ends of a set of upright legs 552. The legs 552 are conveniently of the same general cross-section as the track and the lower ends of the uprights 552 fit into foot flanges 554, which can be bolted to the structure of a vehicle. It will be appreciated that the arrangement 500 can be adjusted in height or width by cutting the lengths of the uprights and track to suit the vehicle, and this gives rise to a deal of flexibility in its installation.

As can be seen from Figure 13 in particular, the thickness 556 of the structure is sufficiently small so as to fit between the outer skin 558 and the inner skin 560 of a vehicle. It will also be seen, from Figures 12 and 14, that the winch motor 30 and drive motor 524 can be incorporated into one of the uprights 552 or the brackets 550 as the case may be.

A remote controller (not shown) is used for independently controlling the winch 30 and the drive motor 524 to effect movement of the lifting point 106 in the vertical 134 and horizontal 126 directions, respectively. The remote controller could be a wired or wireless remote controller, although a wired one is preferred as it is generally more reliable and less likely to be lost. The remote controller suitably has four buttons, arranged as cursors for controlling the winch (up/down) and the drive motor (left/right). An alternative embodiment of the remote control sees it having a joystick which can be moved in the up/down/left/right directions as the case may be to control the winch and drive motor, respectively. Preferably, a safety-shut-off device is provided on the remote controller, such as a key-operated lock to prevent or inhibit the lifting device from being operated inadvertently. Flowever, a simple trigger could be provided which only enables the joystick/cursor buttons to be operated when the trigger is pressed simultaneously.

Referring to Figure 15 of the drawings, a detailed partial cross-sectional view of the lateral track 102 is shown, which comprises a generally C-shaped cross-section extrusion. This has a main linking portion 602 interconnecting limb portions 604, which in turn connect to return portions 606 leaving a gap 608 therebetween. The rear surfaces 610 of the returns 606 provide a surface upon which the rollers 128 of the dolly can roll. The gap/slot 608/502 enables the bight 120 of the cable 108 to pass therethrough and this effectively conceals the whole mechanism, including the threaded rod 520 within the interior of the lateral track.

Referring now to Figures 15 to 22 of the drawings, a second embodiment of a lifting apparatus 800 in accordance with the invention is shown supported on trestles, which are not part of the invention. The lifting apparatus 800 comprises a pair of spaced-apart, parallel C-beams 802, which are held in the said spaced-apart and parallel configuration by a pair of generally rectangular end plates 804, 806 formed from blocks of aluminium, which define and left and right ends, respectively, of the lifting apparatus 800. An intermediate plate 808 is also provided between the C-beams 802, which forms a service void 810 between the C-beams 802 inwardly of the right end plate 806.

The service void 810 houses a control board 812, which is hermetically sealed within an enclosure, as well as a drive motor 814, which drives, via gearbox 816, a lead screw 818 that runs the length of the lifting apparatus 800 parallel to the C-beams 802.

A dolly 820 is formed by an aluminium box frame assembly, which has rollers 822, 824 on its outer surfaces, which engage, respectively, the lower 826 and upper 826 return parts of the C-beams 802. Steel reinforcement bars 828 are affixed to each of the C-beams 802 where the central web 830 of each of the C-beams 802 meets the lower 826 and upper 826 return parts of the C-beams. The rollers 822, 824 therefore roll over upper and lower surfaces, respectively, of the steel reinforcement bars 828, thereby maintaining a fixed pitch and yaw of the dolly 820 relative to the C-beams 802 as it is driven along them by the rotation of the lead screw 818.

The dolly 820 has a follower 830 that engages the lead screw 818, thereby minimising play and backlash.

The dolly 820 also supports a lifting winch 840, which drives a pulley (not visible) around which a lifting strop 842 is wound. Notably, rotation of the winch 840 drives the rotation of a minor lead screw 844, which causes a rod 846 to move left/right relative to the dolly 820 as the winch is operated in either direction. A pair of end stop switches 848 are provided, which thereby define the upper and lower limits of the winch 840 due to a finger 850 of the rod contacting either end stop switch 848 at the respective extents of movement. The positions of the end stop switches 848 relative to the finger 850 can be adjusted to likewise alter the permitted range of movement of the winch 840.

Similarly, further end stop switches 852 are also provided to define the extent of movement of the dolly 820 along the C-beams 802 in either direction.

The invention is not restricted to the details of the foregoing embodiments, which are merely exemplary.

Claims

1. A lifting apparatus, suitable for use inside a vehicle, the lifting apparatus comprising: a pair of parallel beams, the parallel beams each comprising a substantially vertical web portion and substantially horizontal upper and lower return portions extending, respectively, from upper and lower edges of the vertical web portion, the parallel beams being arranged with their upper and lower return portions facing the upper and lower return portions of the opposite beam, such that the opposing lower return portions form a pair of parallel, spaced apart ledges that extend laterally across the ceiling of the vehicle; and a dolly located in the space between the parallel C-beams and having at least two rollers on either side of it that are supported by the parallel, spaced apart ledges, a lifting winch affixed to the dolly, which has a web or cable that can be extended or retracted from below the dolly to lower/raise, respectively, a load, wherein the position of the dolly relative to the C-beams is adjustable by a lead screw running substantially parallel to the C-beams which is rotatable about its axis by a motor, and a lead screw follower fixed to the dolly that engages the lead screw, such that when the motor is driven to rotate the lead screw, the dolly is driven along the C-beams, but when the motor is static, movement of the dolly along the C-beams is inhibited or prevented by the gear ratio of the lead screw to the follower.

2. The lifting apparatus of claim 1, wherein the beams are C-beams.

3. The lifting apparatus of claim 1 or claim 2, wherein the beams are manufactured from aluminium extrusions.

4. The lifting apparatus of claim 3, wherein each beam comprises an elongate steel insert affixed at each of the vertical web portion-horizontal upper/lower return portion junctions.

5. The lifting apparatus of any preceding claim, wherein a vertical dimension of the substantially vertical web portion of each beam is less than 150mm.

6. The lifting apparatus of any preceding claim, wherein a vertical dimension of the substantially vertical web portion of each beam is less than 120mm.

7. The lifting apparatus of any preceding claim, wherein the dolly, the lifting winch, the lead screw, the motor and any associated wiring and control circuitry is located with an envelope defined by the overall length of the beams, their overall height, and by the distance between the outer surfaces of the beams.

8. The lifting apparatus of any preceding claim, wherein when installed, access to the workings of the lifting apparatus are restricted to a direction from below.

9. The lifting apparatus of claim 8, further comprising a removable cover plate, which spans the substantially horizontal lower return portions of the beams thereby forming an enclosure for the mechanism of the lifting apparatus.

10. The lifting apparatus of claim 9, wherein the removable cover plate is formed from a pair of spaced apart sheets, leaving a gap or slot therebetween for the lifting web or cable to emerge from.

11. The lifting apparatus of claim 9, wherein the removable cover plate is formed from a single cover plate with an elongate slot cut into it through which the lifting web or cable emerges.

12. The lifting apparatus of any preceding claim, wherein the electronics of the lifting apparatus are IP-rated against the ingress of airborne particles and liquid droplets of the 1-lOum range.

13. The lifting apparatus of any preceding claim, wherein the lifting winch comprises an override clutch, which permits a load suspended thereby to be lowered in a controlled manner independently of the winch motor.

14. The lifting apparatus of any preceding claim, wherein the dolly comprises a fixing point to which a supplementary pulley system can be connected, such that in the event of a power and/or control failure, the supplementary pulley system can be used to take-over the operation of the lifting winch.

15. The lifting apparatus of any preceding claim, further comprising electronic end stop switches to limit the extent of movement of the dolly relative to the track.

16. The lifting apparatus of any preceding claim, further comprising electronic end stop switches to limit the retraction/extension of the lifting winch.

17. The lifting apparatus of claim 15 or claim 16, wherein the limit switches are normally closed limit switches that are wired in series.

18. The lifting apparatus of any preceding claim, wherein the web or cable is formed into a bight from which a hoist for raising/lowering the load is connected, a portion of the web or cable runs substantially parallel to the beams and the dolly comprises a fairing around which the said web or cable portion passes to form the bight below the dolly, a free end of the web or cable being anchored and being connected to the winch at its other free end such that the length of the bight is independent of the relative position of the dolly and the beams.

19. The lifting apparatus of any preceding claim, wherein the thread pitch of the lead screw and/or the mechanical resistance of the motor is such that rotation of the lead screw by applying a force to the dolly parallel to the lead screw is not possible, thereby locking the dolly in position on the track.

20. The lifting apparatus of any preceding claim, further comprising support legs affixed at their upper ends to opposite ends of the lateral track, the lower ends of the support legs comprising a mounting plate for affixing the support legs to a structure of the vehicle.

21. The lifting apparatus of any preceding claim, further comprising a human interface device for independently controlling the operation of the winch and the drive means.

22. The lifting apparatus of claim 21, wherein the human interface device comprises a wired or wireless remote-control handset.

23. The lifting apparatus of claim 22, wherein the wired or wireless remote-control handset comprises an up/down button or buttons, which when pressed, cause the winch to move in one direction or the other; a left/right button or buttons, which when pressed, cause a motor of the drive means to rotate in one direction or the other.

24. The lifting apparatus of claim 22, wherein the wired or wireless remote-control handset comprises a joystick, which when moved in one axis causes the winch to move in one direction or the other; and when moved in a second axis perpendicular to the first axis, causes a motor of the drive means to rotate in one direction or the other.

25. The lifting apparatus of any preceding claim, further comprising an additional means for locking the position of the dolly on the track at one or more pre-set positions, the additional locking means comprising any one or more of the group comprising: one or more detents on the track into which sprung ball bearings of the dolly engage at one or more positions; a braking system; a latching system; a braking system that requires user intervention to disengage; and a latching system that requires user intervention to disengage.

26. An ambulance comprising the lifting apparatus of any preceding claim.

27. The ambulance of claim 26, wherein the lateral track is located between an outer skin and an inner skin of a ceiling of the ambulance.

28. The ambulance of claim 27, when dependent on claim 20, wherein the or each support leg is located between an outer skin and an inner skin of a side wall of the ambulance.