GB2097756A - Stairlift - Google Patents

Abstract

A stairlift has a power-operated carriage 4 which travels along a track 1 and supports a chair 5 which comprises a pillar 14 on the carriage, a swivellable and vertically adjustable seat 15 mounted on the pillar, and a foot-rest 21 which is supported by the pillar and is angularly adjustable about the pillar relative to the seat. The foot-rest may also be vertically adjustable relative to the seat so that its angular position and height can be altered to suit the requirements of the user. A reversible electric motor, not shown, drives the carriage through a winding drum and rope 26. Switches are provided at each end of the track for controlling operation of the motor, and there are also switches on the carriage and/or chair which are connected to the motor through conductors carried by rails of the track engaged by contacts on the carriage. An interlock switch at the chair prevents the motor from being operated to drive the carriage when the seat is not in a predetermined angular position on the pillar. <IMAGE>

Description

SPECIFICATION Improvements in stairlifts This invention relates to stairlifts suitable for conveying invalid and infirm persons up and down flights of stairs.

It is preferable for persons to be conveyed in a sitting position on such stairlifts. For their safety and security it is desirable for the persons to sit as comfortably as possible whilst they are on the stairlift, if necessary fitted with a suitable seat-belt, and, particularly for their peace of mind, for them to have their feet supported on a firm and adequately proportioned surface. The attitudes in which persons need to sit to be comfortable can vary considerably according to their ages, weights and/or the kind of infirmity from which they are suffering, and yet hitherto no adjustment of the seating on stairlifts has been provided to cater for different requirements.

According to my invention a stairlift is provided which comprises a track adapted to be mounted on a flight of stairs to extend between landings at opposite ends of the flight, a power-operated carriage which travels along the track, and a chair supported on the carriage, the chair comprising a support pillar mounted on the carriage, a seat mounted on the pillar being swivable about the longitudinal axis of the pillar and vertically adjustable on the pillar, and a foot-rest supported by the pillar and angularly adjustable about the pillar relative to the seat.

The vertical adjustment of the seat enables the height of the seat relative to the foot-rest to be adjusted to suit the requirements of a person who is to use the stairlift to ensure that the person's feet are properly supported on the foot-rest. Preferably the range of height adjustment of the seat is such as to accommodate the requirements of persons of widely ranging heights, from children to adults. The angular adjustment of the foot-rest enables the foot-rest to be set at an angular position relative to the seat which best suits the sitting attitude of the person. Thus the foot-rest can be set centrally in front of the seat or at various angular positions to either side of the dead central position. In practice up to 22.5 adjustment of the angular position is sufficient to satisfy most needs of persons using the stairlift.

Persons using the stairlift normally sit facing in the direction which is towards the lower end of the flight of stairs whilst they are being conveyed from one landing to the other. As the seat is swivably mounted on the pillar it can be turned round readily on the pillar to enable a person to get on and off the seat at the respective landings.

The foot-rest is preferably also adjustable for height on the pillar. This extends the range of vertical adjustment which is possible between the seat and the footrest, and enables the foot-rest to be set so as to be as close as possible to the levels of the respective landings when the carriage is at the opposite ends of its travel along the track in use.

In practice height adjustment of the seat and height and angular adjustment of the foot-rest will be made at the time of installation of the stairlift to suit the requirements of an individual person, if the stairlift is to be used by just one person, as is generally the case in a domestic installation, or to suit the average requirements of the majority of persons where several people are to use the stairlift, as for example in a nursing or residential home. It will be appreciated that stairlifts in accordance with the invention have the advantage that though they may perhaps be made of a standard form because of the adjustment facilities provided they can be readily varied to suit the individual seating requirements of use, and in effect, therefore, they are able to be virtually custom made for the particular installations.

The carriage is normally powered by a reversible electric motor adapted to be connected to the mains electricity supply. The motor may be on the carriage itself but preferably it is adapted to be located remotely from the carriage, for example under the flight of stairs or at one of the landings, so that the mains supply voltage is not taken to the lift proper. Operation of the motor may be controlled by switch means, conveniently press button actuated, on the chair, or readily accessible from the chair, and by limit switches which stop the motor when the carriage reaches the ends of its travel along the track.The switch means on the chair, or accessible therefrom, may be such as to require manual retention in the "on" condition to keep the motor running, the switch means reverting to the "off" condition and stopping the motor as soon as the manual retention is interrupted.

Switch means for controlling the motor are preferably also provided at the landings. Safety switch means may be included on the carriage which cause the motor to be stopped automatically if the carriage meets an obstruction during its travel along the track. It is preferred also that an inter-lock switch is provided in association with the chair which stops the motor, or prevents it from starting, when the seat is not in a pre-determined angular position on the pillar, normally dead centre facing in the direction which is towards the lower end of the flight of stairs, for conveying persons up and down the stairs.

The motor preferably drives the carriage through a winding drum and rope or cable, the rope or cable ideally being of high strength galvanised steel manufactured in accordance with BS 2W9. Fail-safe arrester means should be provided on the carriage to operate in the event that the rope or cable should break or slacken so as to prevent the carriage from running back down the track. It is desirable also for the motor to be arranged to be stopped if the rope or cable breaks or slackens.

Electrical connection of the switch means on the chair to the motor controls is preferably by way of conductors carried, with suitable insulation, by the track and engaged by sliding contacts, suitably copper carbon contacts, on the carriage connected to the switch means. This arrangement is generally more reliable and easier to maintain than arrangements in which electrical connections are made by way of trailing cable or self-winding cable reel methods, which are prone to malfunction caused mainly through broken or damaged coiled winding springs and/or carbon brush or contact ring failure, or by way of roller contacts on rails which tend to produce erratic operation due to widely varying electrical resistance between the roller contacts and rails caused by normal dirt and dust being compressed into a patchy insulation film.

The track preferably comprises twin rails which run side by side along the flight of stairs on which the stairlift is to be used.

Ideally the rails are positioned to one side of the flight of stairs, leaving the other side free for persons to walk up and down the stairs in the normal way. For such installation of the rails the carriage preferably supports the chair over or near to the rail which is nearest to the centre of the flight of stairs to make the best use of the space available across the stairs for the chair. The rails may be of the known horizontally flanged type, the carriage being supported on the rails by rollers which engage above and below the horizontal flanges to retain the carriage on the rails.

It is desirable for the carriage to include a body or cover in or under which the rollers, or other means by which the carriage is supported on the rails, are normally located, and electrical contacts, any electrical terminal connections, arrester means and such so that they are protected from damage or fouling by dirt or other matter, and are normally out of the way of persons using the stairlift.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which, Figure 1 is a diagrammatic side view of part of a stairlift in accordance with the invention, Figure 2 is a diagrammatic underneath plan view of a carriage of the stairlift and part of a track on which the carriage runs, and Figure 3 is an end view of the carriage as shown in Fig. 2.

For convenience the stairlift will be described as installed for use. The stairlift comprises a track 1 which extends for the length of a flight of stairs 2 from a lower landing 3 to an upper landing, not shown, a carriage 4 which runs on the track 1, a chair 5 mounted on the carriage 4, and a reversible electric motor, not shown, by means of which the carriage is driven.

The track 1 comprises twin parallel rails 6 of inverted L-section extruded aluminium which are supported, as shown in Fig. 1, on the forward edges of treads of the stairs.

Suitable fixings, not shown, are provided to secure the rails to the treads. The rails are positioned to one side of the flight of stairs and are disposed with their upper, horizontally projecting flanges 7 extending outwardly away from one another, Fig. 3.

The carriage 4 is constructed from two opposite side plates 8 of inverted L-section, Fig. 3, arranged with their upper, horizontally projecting flanges 9 directed inwardly towards one another and supporting a cover plate 10 which spans the two side plates. The side and cover plates are metal. Pairs of ball bearing race steel rollers 11 which rotate about horizontal axes are mounted on the side plates and have rolling engagement with the upper flanges 7 of the rails 6 at their top and underneath surfaces. Further pairs of rollers 1 2 mounted on the underside of the cover plate 10 rotate about axes perpendicular to that plate and have rolling engagement with the facing, inner surfaces of the upright flanges 7' of the rails to guide the carriage in its travel along the rails.

Fixed on the top of the cover plate by a mounting plate 13, and offset towards the rail 6 which is nearest to the centre of the stairway, is a support pillar 14 of the chair 5 which extends vertically from the carriage 4, as shown in Fig. 1. There is provision, not shown, for adjusting the angle of the pillar on the carriage to ensure that the pillar extends vertically whatever the gradient of the stairs.

The pillar 14 swivably supports a seat 1 5 which includes a back rest 16, and, though not shown, preferably arm rests as well. The seat is mounted on top of a sleeve 1 7 which fits over the upper end of the pillar 14 and swivels on a collar 18 which is attached to the pillar and is axially adjustable along the pillar for varying the height of the seat above the carriage. Fixed on the collar 1 8 at angularly spaced positions about the pillar are stops 19 with which a radial projection 20 on the sleeve is engageable to define limits of swivelling movement of the sleeve and seat on the pillar.

The pillar 14 also supports a foot-rest 21.

An arm 22 mounted on the pillar below the collar 1 8 is adjustable for height on and angularly about the pillar and extends radially forwardly from the pillar. At its outer end the arm 22 has a vertically extending tubular socket part 23 in which is vertically slidable a post 24 of circular cross-section which carries the foot-rest 21 at its lower end. The foot-rest is formed by a horizontal rectangular plate, preferably with bevelled or rounded corners, which extends forwardly from the post, and has an upstanding back plate 25 extending along its rear edge which serves to stop a person seated on the chair from moving his feet off the back of the foot-rest and possibly on to the carriage, rails or stairs. The post 24 can be turned in the socket to alter the angular position of the foot-rest relative to the arm, and can be fixed in any adjusted position.Thus the arm and foot-rest are angularly adjustable together about the pillar 14 to set the foot-rest dead in front of the pillar or to either side of a dead central position as required. The foot-rest is adjustable angularly with respect to the arm to set it square to the carriage, or at another angular position to suit the requirements of the user. Up to approximately 22.5 of angular adjustment of the footrest to either side of the dead central front position is preferably provided for. Vertical adjustment of the post in the socket can also be made to adjust the height of the foot-rest.

This adjustment, together with the independent vertical adjustment of the seat, ensures that persons of widely ranging heights, from children to adults, can be comfortably seated on the stairlift, with their feet firmly and securely supported on the foot-rest. In addition, the independent vertical adjustment of the foot-rest permits the foot-rest to be set at the correct level with respect to the levels of the landings when the carriage is at the limits of its travel along the track.

Typically I prefer the foot-rest to be 30.48 cms wide and 35. 56 cms long, that is from front to back of the foot rest.

The carriage is driven along the track by means of the reversible electric motor which is connected to the mains electrical supply and is located under the stairs or on the upper landing within the overall width of the track.

The motor drives through gearing a steel winding drum, not shown, which is positively connected to earth by a spring-tensioned copper-carbon contactor running on the external face of a flange of the drum. One end of a galvanized steel wire rope 26 is attached to the drum and the other end is anchored to the carriage by way of a heavy duty nylon insulation bush, not shown. The two rails 6 of the track are also connected to earth. At the carriage the wire rope earth and the track earth are isolated from each other but the carriage is safely earthed by way of the track earth connection through the steel rollers 11.

A control station, not shown, for starting and stopping and setting the direction of rotation of the motor is provided on the chair for easy access by a person sitting on the chair. Circuitry, less than 1 5 volts D.C., from the control station to a control cabinet, not shown, of the motor, which is positioned near to the motor, is taken along the track by way of aluminium flat-strip conductors 27, Figs. 2 and 3. These conductors are secured to and are insulated from the outer faces of the upright flanges 7' of the rails beneath the upper flanges 7. Electrical pick-up from the conductors 27 is by means of two linear sliding, spring-loaded, copper-carbon collectors 28 carried in nylon carriers 29 mounted on the inner faces of the side plates 8 of the carriage so that the conductors extend horizontally into engagement with the conductors.

The collectors 28 are substantially concealed by, and are protected from accidental and wilful damage by, the upper flanges 7 of the rails. The carriers 29 are adjustable for height on the side plates to position the collectors 28 correctly with respect to the conductors, and to ensure that they are spaced from the upper flanges of the rails. Suitable electrical connections from the two collectors and the wire rope to the control station are made by means of flexible heavy gauge insulated conductor wires, not shown, extending through insulated holes in the cover plate to a terminal box, not shown, secured on top of the cover plate, and by further insulated conductor wires extending by way of the pillar to the control station.

The control station has constant pressure switches by which operation of the motor for "UP" and "DOWN" travel of the carriage is controlled, pressure being required to be maintained on the respective switch to keep the motor energised otherwise the travel of the carriage is stopped. "STOP" switches (preferably of the mushroom-headed press type) are provided of the autolock kind which on the application of finger or hand pressure lock in the "off" position to stop the drive to the carriage. In order to release a "STOP" switch which has been pressed and restore the drive the mushroom head must be turned.

Control stations, not shown, are also provided at the upper and lower landings, suitably wail mounted, and each of those control stations has "UP", "DOWN" and "STOP" switches as well for controlling the motor. Operation of the carriage can thus be controlled from any one of the three control stations.

Pressure sensitive "safety surfaces" are effective over the entire leading and trailing end surfaces of the carriage, down to the uppermost surfaces of the rails, and are faced with foam rubber. Concealed microswitches are provided at the "safety surfaces" and are operated to stop the motor if the carriage should meet an obstruction during its travel in either direction along the track.

A safety switch, not shown, is provided at the lower end of the track. An aluminium housing 30, Figure 1, which stretches across the fuli width of the track is secured to the bottom ends of the rails and forms a track end stop. A microswitch mounted in the housing has its moving contact projecting out of the housing 30 through an aperture, and that contact is protected and operated by a hinged plate, not shown. The hinged plate is engaged by the "safety surface" at the lower end of the carriage when the carriage reaches the lower end of the track with the result that the microswitch in the housing is operated and/or the microswitch at the "safety surface" to stop the motor. The two microswitches are in series.

Typically in practice operation of the microswitches at the "safety surfaces" on meeting obstructions, and operation of the microswitch in the housing at the lower end of the track or the microswitch at the "safety surface" at the lower end of the carriage, causes the carriage to stop in a travelling distance of less than 15mm.

A similar safety switch is provided at the upper end of the track for stopping the motor, in addition to the normal pre-set "travel limit" and "final limit" switches, not shown, operated by the carriage itself. The position of the "travel limit" switch along the track is adjustable to vary the actual position of stopping of the carriage at the upper end of the track. The stopping position is usually determined so as to bring the foot-rest to the level of the upper landing. The "final limit" switch is arranged to be operated after a pre-determined distance of over-travel of the carriage in the unlikely event that the "travel limit" switch is not operated to stop the carriage. When the "final limit" switch is operated it de-energises a relay in the control cabinet which causes the motor to stop.Upon de-energisation of the relay an indicator light on the control cabinet which causes the motor to stop. Upon deenergising of the relay an indicator light on the control cabinet is illuminated to show that the carriage has over-run the normal upper travel limit position. The carriage must then be moved back manually to the normal travel limit position before the relay can be reenergised by means of a re-set switch.

An inter-lock switch, not shown, is provided at the chair, conveniently on the collar 1 8 to be operated by a suitable element on the sleeve 17, which operates to prevent travel of the carriage when the seat is not in the safe travelling position, i.e. facing straight ahead down the stairs. The inter-lock switch isolates the "UP" and "DOWN" switches of the control stations on the chair and two landings from the motor whilst the chair is not in the safe travelling position, and leaves the "STOP" switches effective.

Preferably all the switches are such that in the normal travel condition between the limits of the travel of the carriage along the track the contacts of the switches are closed, including those of the "UP" or "DOWN" switch which has been operated to initiate the travel, so that they are all ready to be operated to break the circuit and stop the motor at any time during the travel should that be necessary.

A mechanical rope-sensing arrester device, not shown, of known kind, is located on the carriage which operates to lock the carriage on the track rails and prevent it from travelling down the track in the event that the wire rope should break. When the arrester device is operated it simultaneously causes the motor to be stopped by operating a "slack rope" switch and by breaking the earth connection made through the wire rope. The "slack rope" switch operates whenever there is slackness in the wire rope, for whatever reason, to stop the motor instantaneously. When operated the switch isolates the "DOWN" switches at all three control stations from the motor but leaves the "UP" switches available for controlling the motor.

The motor circuit incorporates an over-load protection device, and a current amplifier which allows the circuit to ignore increases in contact/conductor resistance between the carriage and track below a predetermined level, normally below 400 Ohm.

Claims (24)

1. A stairlift comprising a track adapted to be mounted on a flight of stairs to extend between landings at opposite ends of the flight, a power-operated carriage which travels along the track, and a chair supported on the carriage, the chair comprising a support pillar mounted on the carriage, a seat mounted on the pillar being swivable about the longitudinal axis of the pillar and vertically adjustable on the pillar, and a foot-rest supported by the pillar and angularly adjustable about the pillar relative to the seat.

2. A stairlift according to claim 1 wherein the foot-rest is vertically adjustable on the pillar.

3. A stairlift according to claim 1 or claim 2 wherein the seat is mounted on a sleeve which is engaged telescopically with the upper end of the pillar and swivels on a collar which is attached to the pillar and is axially adjustable along the pillar for varying the height of the seat.

4. A stairlift according to any preceding claim wherein means is provided acting between the pillar and the seat which limits the extent of the swivelling movement of the seat on the pillar.

5. A stairlift according to claim 4 as dependent from claim 3 wherein the means for limiting the swivelling movement of the seat on the pillar comprises stops provided on the collar at angularly spaced positions about the pillar, and a projection on the sleeve which moves between and engages with the stops.

6. A stairlift according to any preceding claim wherein the foot-rest is carried by an arm mounted on and projecting laterally from the pillar.

7. A stairlift according to claim 6 as de pendent from claim 2 wherein the arm is adjustably mounted on the pillar such that its height on and angular position about the pillar can be adjusted.

8. A stairlift according to claim 6 or claim 7 wherein the foot-rest is vertically and angularly adjustable relative to the arm for altering its height with respect to the chair and its angular position with respect to the pillar.

9. A stairlift according to claim 8 wherein the arm has a socket and the foot-rest is fixed to a post which is vertically and angularly adjustable in the socket.

10. A stairlift according to any preceding claim wherein the foot-rest comprises a substantially rectangular plate having a rear edge along which an upstanding back plate extends which serves to restrain a person when seated on the chair from moving his feet off the back of the foot-rest.

11. A stairlift according to any preceding claim wherein the track comprises twin rails which run side by side along the flight of stairs on which the stairlift is installed for use, the carriage spanning the two rails.

1 2. A stairlift according to claim 11 wherein the pillar is mounted on the carriage in an off-set position over or near to one of the rails.

1 3. A stairlift according to claim 11 or claim 1 2 wherein the rails have horizontallyprojecting lateral flanges and the carriage is supported and retained on the rails by rollers on the carriage which rotate about horizontal axes and engage above and below the flanges.

14. A stairlift according to claim 1 3 wherein the carriage has further rollers thereon which engage with, and rotate about axes parallel to, faces of upright parts of the rails to guide the carriage in its travel along the rails.

1 5. A stairlift according to claim 1 3 or claim 14 wherein the carriage has a cover under which the rollers are disposed and on which the pillar is mounted.

16. A stairlift according to any preceding claim wherein the carriage is power-operated by means of a reversible electric motor which is adapted to be located remotely from the carriage when the stairlift is installed for use, and which drives the carriage through a winding drum and rope or cable.

1 7. A stairlift according to claim 1 6 wherein switch means is provided on the chair and/or carriage for controlling operation of the motor, and electrical connection of the switch means to the motor includes conductors carried by the track and engaged by contacts on the carriage connected to the switch means.

1 8. A stairlift according to claim 1 7 wherein the contacts comprise spring-loaded, electrically conductive, collectors linearly slidable in carriers of insulating material which are adjustably mounted on the carriage such that the positions of the collectors can be adjusted with respect to the rails and conductors.

19. A stairlift according to claim 1 7 or claim 1 8 wherein the electrical circuit of the motor incorporates an over-load protection device and a current amplifier which allows the circuit to ignore increases in contact/conductor resistance between the carriage and track below a pre-determined level.

20. A stairlift according to any of claims 1 6 to 1 9 wherein a switch operatively connected to the motor is provided at the pillar and an element swivable with the chair cooperates with the switch such as to operate the switch to prevent the motor from moving the carriage when the seat is not in a predetermined safe travelling position.

21. A stairlift according to any of claims 1 6 to 20 wherein pressure sensitive surfaces are provided at opposite ends of the carriage at which switches are provided which are electrically connected to the motor and are adapted to be operated to stop the motor if either of the surfaces should meet an obstruction during the travel of the carriage along the track in either direction.

22. A stairlift according to any of claims 16 to 21 wherein limit switches are provided at upper and lower ends of the track in housings secured to the track, the limit switches being electrically connected to the motor and being adapted to be operated by the carriage to stop the motor when the carriage reaches the upper and lower ends respectively of the track.

23. A stairlift according to claim 22 wherein a final limit switch is provided at the upper end of the track beyond the said limit switch at that end of the track, which final limit switch is electrically connected to the motor and is adapted to be operated by the carriage to stop the motor in the event that the said limit switch should not be operated by the carriage to stop the motor.

24. A stairlift substantially as described herein with reference to and as illustrated by the accompanying drawings.