EP2432724A1

EP2432724A1 - Override system for a stairlift

Info

Publication number: EP2432724A1
Application number: EP09748437A
Authority: EP
Inventors: Nick Luckett
Original assignee: Minivator Ltd
Current assignee: Handicare Accessibility Ltd
Priority date: 2008-10-13
Filing date: 2009-10-14
Publication date: 2012-03-28
Anticipated expiration: 2029-10-14
Also published as: GB2464336A; GB0818737D0; GB2464336B; WO2010043869A1; WO2010043869A8; EP2432724B1

Abstract

An override system for a stairlift, the stairlift comprising a rail (10) and an electronically controlled actuator (20) for moving at least a part of the rail, comprises override means (28; 34) adapted to force the actuator to move the at least part of the rail instead of the electronic control. The stairlift rail may comprise a first rail portion (18) fixed to a flight of stairs, a second rail portion (19) moveable with respect to the first rail portion and the electronically controlled actuator (20) may be operable for moving the moveable rail portion with respect to the first rail portion. The override means may thus be adapted to force the actuator to move the second rail portion instead of the electronic control.

Description

Override System for a Stairlift

The present invention relates to an override system for a stairlift and, in particular but not exclusively, to an override system for use in the event of a power failure of an electronically controlled stairlift.

Stairlifts provide transportation of a person (or a wheelchair or such like) up and down stairs, assisting people who find ascending and descending stairs difficult and in particular those with limited mobility. Typically, a rail is mounted to or near a flight of stairs and a chair (or platform for a wheelchair) is mounted via a carriage on the rail. The carriage can be controlled by the user via a control means to travel along the rail and up and down the stairs. The rail may be straight or curved, depending on the configuration of the staircase up and down which the stairlift is required to travel.

The rail needs to extend beyond the end of the flight of stairs, to enable a user to mount/dismount. As such, stairlift rails will obstruct a doorway if the stair and doorway are in close proximity. One way of overcoming this problem is to hinge an end of the rail away from the door, e.g. as shown in Figure 1a, or configure an end of rail so it can be folded out of the way, e.g. as shown in Figure 1b.

Stairlift rail systems are typically controlled electronically and, in normal working order, will not obstruct access to a room or prevent a door from opening as they are "parked" out of proximity of the door. In the example shown in Figures 1a and 1b, the lower end of the stairlift rail is hinged or foldable with respect to the majority length of the rail. The end of the rail can thus be folded upward and away from the doorway to its parking position.

The systems shown in Figures 1a and 1b may suffer the disadvantage that, in the event of power failure, the end of the rail could remain in the fully down (or fully up) position, thus blocking access/egress to/from a room. It is thus desirable to provide a means of manually operating the folding/hinge mechanism to allow access/egress in emergency conditions.

A known way to achieve this is by providing the moving part of the folding rail system with a counter balance, to allow ease of manual handing to move the hinged part of the rail. A problem with this system, however, is that components of the drive system are exposed. Having moving parts exposed could be potentially dangerous (e.g. to articles, fingers etc getting caught therein). The rails need to be contiguous in order for the carriage to move across them and, as such, they are potentially a trapping/shearing hazard. In addition, the links in the rails may trap or crush anything therebetween. Open housings, carriages etc. also make the system vulnerable to damage and contamination from dirt which could jeopardise operation of the stairlift. Furthermore, the exposed drive system components may be aesthetically displeasing.

Such problems could be avoided by using a straight track (i.e. non-hinged) system. One particular system manufactured by Minivator Limited incorporates a sliding track system that can slide out of the way of a doorway so as not to block access/egress as discussed above. Figure 2 shows such a system in situ on a staircase. Here, the rail comprises a first rail section that is moveable longitudinally up and down a flight of stairs with respect to fixings on the stairs. This allows controlled movement in a straight line of action to withdraw the lower part of the rail away from a door e.g. at he bottom of the stairs to allow access/egress.

However, accessing the stairlift drive system in order to override it in the event of, for example, a power failure is difficult, as the drive mechanism is typically concealed from view - i.e. under the rail shown in Figure 2.

The present invention has been designed with the foregoing in mind. According to a first aspect of the present invention there is provided an override system for a stairlift, the stairlift comprising a rail and an electronically controlled actuator for moving at least a part of the rail, the override system comprising override means adapted to force the actuator to move the at least part of the rail instead of the electronic control. For a stairlift rail comprising a first rail portion fixed to a flight of stairs, a second rail portion moveable with respect to the first rail portion and an electronically controlled actuator for moving the moveable rail portion with respect to the first rail portion, the override means is adapted to force the actuator to move the second rail portion instead of the electronic control.

The invention is thus useful in the event of motor failure (e.g. a power cut) where the moveable stairlift rail may otherwise be stuck in a position that blocks access/egress to/from a room. Advantageously, the invention provides a means of manipulating the actuator (e.g. manually).

According to a second aspect of the present invention there is provided an override system for a stairlift, the stairlift comprising a rail and an electronically controlled actuator for moving at least a part of the rail, the override system providing an override means configured to extend accessibility beyond the confines of the rail, e.g. to manipulate and or move the actuator. The stairlift may be of the type comprising a rail having a first rail portion fixed to a flight of stairs, a second rail portion moveable with respect to the first rail portion and an electronically controlled actuator for moving the moveable rail portion with respect to the first rail portion.

The invention provides a means of facilitating access to the actuator, e.g. by effectively extending the size of the actuator, preferably in a direction transverse to the longitudinal length thereof. The invention is thus useful in the event of motor failure (e.g. a power cut) where the moveable stairlift rail may otherwise be stuck in a position that blocks access/egress to/from a room as it provides a way to gain access to (and manipulate) the actuator in order to force movement thereof.

In accordance with either of the above aspects, the following embodiments are provided.

In an embodiment, the actuator is operable for converting rotation motion to linear motion, and the override means is adapted to cause the actuator to rotate.

The override means may be directly attachable to the actuator to force the movement.

Alternatively, the override means may comprise an intermediate component for coupling the override means to the actuator. Preferably, the intermediate component comprises a rotation component and rotation of the rotation component causes the actuator to rotate. The rotation component may comprise a first rotation component attached to or provided on the actuator and rotation of the first rotation component causes the actuator to rotate. The rotation component may further comprise a second rotation component coupled to the first rotation component. Rotation of the second component may cause rotation of the first rotation component.

In an embodiment, the intermediate component comprises a pulley system. The rotation component may comprise any one or more of a wheel, a sprocket or a gear. The override system may further comprise coupling means for coupling the rotation component to the actuator. The coupling means may comprise any one or more of a chain, rope, cable or belt encompassing the actuator or a rotatable part thereof and the rotation component. The coupling means may comprise timing means for controlling the rotation of the rotation member. In an embodiment, the override means comprises a tool adapted to fit in and/or around at least a part of the rotation means. The tool may be a spanner, e.g. a C-shaped spanner. It is an advantage that a simple hand tool, e.g. a spanner, is inexpensive to manufacture/purchase, and easy to operate.

Thus, in its simplest form, embodiments of the invention provide a means of manipulating (e.g. mechanically and/or manually) the actuator e.g. in the event of a power failure. The first rotating member provides for this. The second rotating member (and the coupling between the first and second rotating members) facilitates the manipulation by extending accessibility to the actuator. The tool (e.g. spanner) provides an easy and inexpensive way of manipulating the actuator.

According to a third aspect of the present invention there is provided a stairlift comprising a chair mounted on a rail and an electronically controlled actuator for moving the chair along the rail and the override system according to any above aspect and or embodiment. The stairlift rail may comprise a first rail portion fixed to a flight of stairs, a second rail portion moveable with respect to the first rail portion, and the override means is preferably adapted to force the actuator to move the second rail portion instead of the electronic control.

The actuator may comprise a rotatable member that is free to rotate, but not free to move axially along the rail, when the override system is in use. Means may be provided for restricting manipulation of the actuator when normally powered.

An embodiment of the invention will now be described by way of example with reference to the following drawings, wherein:

Figure 3 is shows a cutaway view of a stairlift rail, including an override system according to an embodiment of the present invention; Figure 4 shows an exploded view of the stairlift rail of Figure 2 or Figure 3 (without the override system);

Figure 5 shows an enlarged cutaway view of the underside of a stairlift rail, including an override system according to an embodiment of the present invention;

Figure 6 is a view of the override system and fixed stairlift rail section of Figure 3 in use on a stairlift rail; and

Figure 7 is an enlarged view of the underside of the stairlift rail of Figure 3.

Figure 3 shows one end of a stairlift rail 10. The rail 10 is mounted to a staircase via fixings or feet 12. The rail 10 may be a conventional stairlift rail, e.g. formed by an extrusion process. The fixings 12 comprise bearing plates 14 which are attached (e.g. by screws) to treads of a flight of stairs (not shown, although Figure 2 shows a similar rail in situ on a flight of stairs). Referring again to Figure 3, the plates 14 are also attached to a fixed portion 18 of the stairlift rail 10 via a pivotal or hinged connection 16. The pivot 16 enables the rail 10 to be positioned on stairs at different angles in order to accommodate stairs of varying heights.

The stairlift rail 10 also comprises a moveable section or slide track 19. The movement of the slide track 19 is controlled by an actuator (e.g. a linear actuator), mounted inside the stairlift rail 10. The actuator has a shaft 20 and is controlled by an electronic drive system (not shown) contained in a printed circuit board (PCB). The actuator 20 is preferably a self contained unit, comprising an epicyclic motor and gearbox in line with its longitudinal axis. Alternatively, separate actuator, motor and gearbox components could be utilised to achieve the same result. As can be seen from Figures 3 and 4, the actuator 20 is located in the centre of the rail 10 and, as such, it is difficult to access the actuator 20 to manipulate it. The PCB may also be located at the mid point of the rail, underneath and inside of the extruded rail.

The actuator 20 is connected to the fixed portion 18 of the rail 10 with attachment means 22. The actuator 20 can move the slide track 19 from the position as shown in Figure 3 longitudinally upward, to retract the end of the track 19, and it can move the track 19 longitudinally down again. One or more rollers 21 are provided between the fixed and moveable stairlift rail sections 18, 19 to facilitate the movement therebetween, as shown in Figure 4.

A gas spring or strut 24 is also provided. The gas strut 24 is a counter balance for the user's mass (e.g. rated at 1040 Newtons to ensure the user does not free fall down the stairs). This preload is accounted for in the force supplied by the actuator 20. As can be seen from Figures 3 and 4, the gas spring 24 is attached to the fixed part 18 of the stairlift rail 10 with a connector 25. The moving connections of the actuator 20 and the gas strut 24 are secured to the connector 26, which is then secured e.g. clamped to the moving rail 19 at a predetermined point on the rail 19. The connector 26 comprises an L-shaped mounting, which is attached (e.g. by screws as shown in Figure 4) to the rail 19. The L-shaped mounting mounts the actuator 20 and gas strut 24 inside the rail 19.

The stairlift comprises means 27 for providing access to the actuator 20 and/or for forcing the actuator 20 to move, e.g. in the event of a power failure. Preferably the forced movement is mechanical rather than electronic. In the event that the PCB fails, a voltage could be supplied to the motor to move the track system to a desired position under emergency conditions. This is acceptable if the motor drive is in working order on the actuator. However, if the motor fails for some reason, e.g. if the brushes or internal windings of the motor fail, the motor will not move - hence rendering the track 19 immoveable. In an embodiment, and unlike conventional actuators, the actuator 20 comprises a first rotating member 28. The first rotating member 28 is provided on or at an end of the actuator 20 - as is best shown in Figures 3 and 5. The first rotating member 28 is free to rotate when required, e.g. in the event of a power failure. However, tightening a clamp screw or nut 40 prevents the first rotating member rotating otherwise. The second rotating member 34 is thus held captive by the clamping screw or nut 40, to prevent inadvertent rotation under normal powered operation. However, in emergency operational conditions, the clamp 40 can be slackened to allow rotation of the secondary rotation member 34.

In an embodiment, a second rotating member 34 is provided on the fixed rail section 18. The second rotating member 34 is configured for coupling to the first rotating member 28 of the actuator 20.

The first and second rotating members 28, 34 may be coupled together by means such as a belt. This could be achieved by a chain and sprocket, gears, rope or any means of rotation under a controlled manner. In an embodiment, e.g. as shown in Figures 3, 5, 6 and 8, a pulley system 36 may be utilised. The pulley system may comprises a timing belt, in order to obtain positive drive, although a plain pulley system could also be utilised.

The clamp 40 thus stops the pulley 28 from rotating via the timed belt 36. As such, the second rotating member 28 cannot move axially, due to the provision of a bearing 29 captive by one or more abutment surfaces 30. Figure 6 shows how the bearing surfaces 30 may be provided by an aperture in the fixed stairlift rail section 18.

The provision of the second rotating member 34 (coupled to the first rotating member 28) extends the accessibility to rotate the actuator 20, beyond the confines of the rail system 10, which would normally be off limits due to the installation on a flight of stairs and configuration of the conventional stairlift components. Embodiments of the invention thus provide a means of forcing rotation of the first rotating member 28, and hence driving the normally fixed end 32 of the actuator 20 in both directions.

The internal mechanism of a linear actuator usually works on a lead screw type mechanism, typically Acme or balls screw. Conventional actuators require an end thereof to be fixed in order to prevent axial rotation at each end in order to allow the lead screw to extend. Rotation of the actuator 20 is translated into longitudinal movement in order to move the slide track 19 (e.g. as shown in Figure 4 which shows a conventional actuator arrangement). Embodiments of the invention, however, provide for rotation of the normally extending fixed end 32 of the actuator 20, to simulate the extension of the actuator 20.

According to embodiments of the invention, means are provided for rotating or moving the actuator connection 28, 34, 36 to the fixed part 18 of the rail system. An extension 37 is provided on an end of the actuator 20, attached (e.g. riveted) to the actuator shaft 20. The extension is coupled to the first rotating member 28 (which is in turn coupled to the second rotating member 34.

By turning the second rotating member 34, the actuator shaft 32 can be rotated, and hence it is possible to move the normally fixed centres of the actuator 20 when no electrical power is applied to extend or retract the actuator 20. Thus it is possible to override the position of the slide track 19, and thus move the track/obstruction from the doorway.

Thus, embodiments of the invention provide means for rotating the actuator shaft 20, to extend the internal screw and hence extend or contract the normally fixed end 32. To put this in context, Figure 2 shows a sliding stairlift rail fixed to a flight of stairs. For such a rail, there is no way of overriding the actuator if it failed. The standards (ISO 9386-2: 2000: Powered stairlifts for seated, standing and wheelchair users moving in an inclined plane and BS5776:1996 Powered stairlifts) dictate this. Embodiments of the invention thus serve to override the permanently coupled actuator which takes all the user load and forces.

As can be seen from Figure 5, the actuator extension 37 may comprise the connection to the fixed rail section 18, and may provide the bearing 29. The connection 37 is the part that is under load and must be controlled so as not to cause an uncontrolled movement of the rail system. This connection is stressed to take linear forces exerted under maximum working load. Forced rotation of the second rotating member 34 causes the first rotating member to rotate, causing the actuator extension 37 to rotate, rotating the actuator 20, such movement being translated by the actuator into linear movement of the moveable rail section 19. The connection of the actuator 20 to the fixed portion 18 of the stair rail system is thus manipulated in order to extend or contract the coupling point - in order to slide the moveable part 19 of the rail with respect to the fixed rail 18.

As can be seen e.g. from Figures 3-5, the end of the actuator 20 points downward towards the stairs and is encased within the stairlift rail 10. This is advantageous because it ensures moving components are hidden from view and difficult to access but, as such, this also hinders access to the drive components in the event of a power failure. The end of the actuator 20 may alternatively point upward. Whilst this increases accessibility to the drive components, this also exposes moving components and may affect the arrangement of components that provide for the sliding motion of the stairlift rail 10. Embodiments of the present invention may, however, be employed in either case. Due to the increased accessibility to rotate the actuator 20 provided by embodiments of the invention, the secondary rotating member 34 may be rotated manually (e.g. directly by hand). In an embodiment, a handle or wheel 41 may be used for hand winding the actuator 20. Figure 7 shows a hexagon drive 41. Such manual adjustment would not have been possible in known arrangements, as access to the actuator was too limited.

Alternatively, a tool can be provided to assist rotation of the secondary rotation member 34. For example, a spanner, e.g. a ¹C spanner, 38 can be used to cause rotation. In an embodiment, the position of the belt around the secondary rotating member 34 can be adjustable in order for the spanner 38 to be positioned on the rotating member 34, e.g. as shown in Figure 5.

In another embodiment, a direct inline drive onto the end 32 of the actuator 20 could be used to rotate and control rotation of the actuator 20. An auxiliary shaft (not shown) could be provided to cause rotation of the normally extending fixed end 32 of the actuator 20. If the actuator is positioned in a downward facing attitude, this could give rise to access issues. To overcome this, the actuator 20 could be positioned in an upward facing attitude. The auxiliary shaft would need to be adjustable in length to suit changes in stair length. Care must also be taken so that the shaft does not interfere with end safety edges dictated by moving components.

Claims

1. An override system for a stairlift, the stairlift comprising a rail and an electronically controlled actuator for moving at least a part of said rail, the override system comprising override means adapted to force said actuator to move said at least part of said rail instead of said electronic control.

2. The override system of claim 1 , the stairlift comprising a rail having a first rail portion fixed to a flight of stairs, a second rail portion moveable with respect to said first rail portion and an electronically controlled actuator for moving said moveable rail portion with respect to said first rail portion, wherein the override means is adapted to force said actuator to move said second rail portion instead of said electronic control.

3. An override system for a stairlift, the stairlift comprising a rail and an electronically .controlled actuator for moving at least a part of the rail, the override system providing an override means configured to extend accessibility beyond the confines of the rail.

4. The override system of any of claims 1 to 3, wherein said override means is directly attachable to said actuator to force said movement.

5. The override system of any of claims 1 to 4, wherein said override means comprises an intermediate component for coupling said override means to said actuator.

6. The override system of any of claims 1 to 5, wherein said override means is adapted to cause said actuator or a part thereof to rotate.

7. The override system of claim 6, wherein said intermediate component comprises a rotation component and rotation of said rotation component causes said actuator to rotate.

8. The override system of claim 7, wherein said rotation component comprises a first rotation component attached to or provided on said actuator and rotation of said first rotation component causes said actuator to rotate.

9. The override system of claim 8, wherein said rotation component comprises a second rotation component coupled to said first rotation component, and wherein rotation of said second component causes rotation of said first rotation component.

10. The override system of any of claims 7 to 9, wherein said intermediate component comprises a pulley system.

11. The override system of any of claims 7 to 10, wherein said rotation component comprises any one or more of a wheel, a sprocket or a gear.

12. The override system of claim 11 , further comprising coupling means for coupling said rotation component to said actuator, said coupling means comprising any one or more of a chain, rope, cable or belt encompassing said actuator or a rotatable part thereof and said rotation component.

13. The override system of claim 12, wherein said coupling means comprises timing means for controlling the rotation of said rotation member.

14. The override system of any of claims 7 to 13, wherein said override means comprises a tool adapted to fit in and/or around at least a part of said rotation means.

15. The override system of any of claims 7 to 14, wherein said tool is a spanner.

16. A stairlift comprising a chair mounted on a rail and an electronically controlled actuator for moving said chair along said rail and an override system according to any of claims 1 to 15.

17. The stairlift of claim 16, wherein said rail comprises a first rail portion fixed to a flight of stairs, a second rail portion moveable with respect to said first rail portion, and wherein said override means is adapted to force said actuator to move said second rail portion instead of said electronic control.

18. The stairlift of claim 16 or claim 17, wherein said actuator comprises a rotatable member that is free to rotate but not free to move axially along said rail when said override system is in use.

19. An override system substantially as hereinbefore described with reference to the Figures of the accompanying drawings.

20. A stairlift substantially as hereinbefore described with reference to the Figures of the accompanying drawings.