Improvements in or relating to stairlifts

Abstract

A seat belt assembly for mounting on a stairlift comprises a belt 13 attached to the stairlift in a first position, a fixing mounted on the stairlift at a second position and locking means between the

Description

This invention relates to stairlifts and, in particular, to a seat belt assembly for a stairlift. Background to the Invention A stairlift is typically used by persons having one or more physical limitations and measures must be included and implemented to ensure safe use. Amongst the required (in some jurisdictions mandatory) safety measures is the need to provide a safety belt to retain a user on the stairlift during a journey; however some seat belt arrangements are fiddly to use and, as a consequence, some users elect not to apply the belt. It is an object of this invention to go at least some way in addressing the aforementioned problem, or at least provide a novel and useful choice. Summary of the Invention In a first aspect the invention provides a seat belt assembly configured for mounting on a stairlift, the assembly comprising: a belt attached to the stairlift at a first position, a fixing mounted on the stairlift at a second position spaced from the first position; and locking means arranged and configured between the belt and the fixing such that, in use, the belt is drawn across a user positioned on the stairlift and engaged with the fixing, wherein the locking means comprises a socket on the one hand and a spigot on the other hand, magnetic means being provided to draw the spigot into the socket, the socket and spigot being configured to allow the spigot as it engages in the socket, to displace, to a locking position in which the spigot is mechanically retained within the socket. Preferably said belt is attached to a retraction mechanism. Preferably said spigot is drawn into the socket along an engagement axis and, once engaged, is drawn into the locking position in a direction substantially perpendicular to the engagement axis. Preferably the socket and spigot are configured such that, as the spigot engages in the socket, tension applied to the belt serves to bias the spigot toward said locking position. Preferably said spigot is rotatable with respect to the socket about a locking axis when in the locking position. Preferably said socket includes a lip, and said spigot includes an annular groove that engages over the lip when in the locking position. Preferably said socket includes an entrance aperture configured to guide said spigot in the direction of said lip. Preferably said entrance aperture includes spaced edges tapering in a direction toward said lip Preferably said socket includes a ramp configured to deflect the spigot in a direction out of the socket when a force is applied to remove the disengage the spigot from the locking position. Preferably the spigot is fixed to the belt. Preferably said spigot includes a pull strap projecting therefrom. Preferably the magnetic means is configured to draw the spigot toward the locking position. Preferably the magnetic means comprises a first magnet mounted on or within the socket and a second magnet of reverse polarity mounted on or within the spigot Preferably the first and second magnets are offset laterally with respect to a vertical axis, upon initial engagement of said spigot in said socket but are substantially aligned when said spigot is in the locking position. In a second aspect the invention provides a stairlift chair including the seat belt assembly as set forth above. Preferably the stairlift chair has a seating surface, wherein said retraction mechanism is fixed at or adjacent to a side edge of said seating surface and said socket is fixed at or adjacent to an opposed side edge of said seating surface. Preferably the stairlift chair has a pair of spaced armrests, wherein said retraction mechanism is fixed to one of said pair of armrests and said socket is fixed to the other of said pair of armrests. Preferably the stairlift chair has a backrest, wherein said retraction mechanism is fixed at or adjacent to a side edge of said backrest and said socket is fixed at or adjacent to an opposed side edge of said backrest. In a third aspect the invention provides a stairlift including the stairlift chair as set forth above. In a fourth aspect the invention provides a perch-based stairlift including the seat belt assembly as set forth above. In a fifth aspect the invention provides a stand-on stairlift including the seat belt assembly as set forth above. In a sixth aspect the invention provides a stairlift as set forth above including an electronic control unit (ECU); and a hand control and occupation sensor operatively connected to said ECU; wherein said seat belt assembly includes sensing means connected to said ECU operable to establish when said spigot is in the locking position, said ECU being configured to disable said hand control when said occupation sensor determines the presence of a user positioned on the stairlift, and said spigot is not in the locking position. Preferably said sensing means in positioned on or within said socket. Preferably said sensing means includes a mechanical switch. Preferably said sensing means includes a printed circuit board mounted on an annular carrier. In a sixth aspect the stairlift as set forth above further includes a receptacle mounted adjacent to said retraction mechanism, said receptacle including means to draw said spigot into a storage position when said spigot is withdrawn from said socket. Many variations in the way the present invention can be performed will present themselves to those skilled in the art. The description which follows is intended as an illustration only of one means of performing the invention and the lack of description of variants or equivalents should not be regarded as limiting. Wherever possible, a description of a specific element should be deemed to include any and all equivalents thereof whether in existence now or in the future. The scope of the invention should be limited by the appended claims alone. Furthermore, the invention may comprise any novel combination of individual elements or components described in the following example that may combine to provide a stairlift seat belt assembly, a stairlift chair and / or a stairlift and should not be confined to the particular combination or combinations of elements or components described. Brief Description of the Drawings One form of stairlift seatbelt assembly embodying the invention will now be described with reference to the accompanying drawing in which: Figure 1: shows a schematic isometric view of a stairlift chair to which a seat belt assembly according to the invention may be fitted; Figure 2: shows an enlarged isometric view of part of the chair shown in Figure 2 with a seat belt assembly according to the invention fitted thereto; Figure 3: shows a schematic section view through a locking arrangement included in a seat belt assembly according to the invention; Figure 4: shows further detail of part of that shown in Figure 3; and Figure 5: shows a sequence for connecting the assembly shown in Figures 2 to 4. Detailed Description of Working Embodiment The invention provides a seat belt assembly for a stairlift. In the context of this invention, the term stairlift should be interpreted as including a stair mounted lift in which a user is seated in a chair, perched on a support, or standing on a platform while moving up and down a staircase. In the following a non-limiting example is described in which the seat belt assembly is applied to a stairlift chair but those skilled in the art will readily appreciate that the novel aspects of the seat belt assembly described herein are equally applicable to other configurations of lift that are fixed to a staircase for transferring users between floors of a building. In the example of Figure 1 the chair 5 comprises a seating surface 6, a back rest 7 and a pair of armrests 8. Seat bolsters 9 are provided at the rear of the seating surface 6 and side bolsters 10 project from opposite sides of the backrest 7. The armrests 8 are mounted on uprights 11. In the conventional manner the seat belt assembly may further include a retraction mechanism (not shown) mounted on one side of the chair and locking means 12 mounted on the opposite side of the chair such that, in use, the belt 13 (Figure 3) is withdrawn from the retraction mechanism, passed over a user seated in the chair, and the locking means engaged to set the belt in its operating state. However, the provision of a retraction mechanism is by no means essential, and belt and belt mounts of all configurations known in the art may be adopted without departing from the scope of the invention. In summary, the form of belt mount, including the form of retraction mechanism if present, does not form part of the invention. On the other hand, the locking means is central to the invention and will be described in detail below. As shown in Figures 2 to 5, the locking means in its broadest iteration, comprises a spigot and socket arrangement in which the spigot is drawn into the socket under magnetic influence and, when within the socket, is drawn or displaced into mechanical engagement with the socket to set the belt in its operating state. In the example the socket is fixed to the chair while the spigot is fixed to the belt, and this embodiment of the invention will be described on that basis. It should be appreciated, however, that embodiments could be provided in which the spigot is fixed to the chair and the socket is fixed to the belt. The socket 15 is shown in Figure 2 mounted on one of the side bolsters 9 and has an entrance aperture 16, a lip 17 and a ramp 18. The spigot 20 is drawn into the socket 15 along engagement axis 19 by magnetic means acting between the socket and spigot. In the example shown the magnetic means is configured not only to draw the spigot into the socket, but also to draw the spigot toward the locking position. This is preferably achieved by providing first magnet 21a in the socket and second magnet 21b, of reverse polarity, in the spigot. As can be seen in Figure 5, the magnets 21a and 21b are offset laterally with respect to a vertical axis as the spigot enters the socket along engagement axis 19. Accordingly, as the spigot continues to enter the socket the magnets seek to align with one another and, in so doing, draw the spigot into the locking position. Preferably, in the latter position, both magnets 21a and 21b are centred around locking axis 24. The engaging force applied by magnets 21a and 21b may be supplemented by tension applied to the belt 13 by a tensioner, if present. The entrance aperture 16 is preferably shaped in a manner that guides the spigot toward the mechanical locking position under the influence of the engaging forces. In the depicted example, this feature is provided by inwardly directed edges 22 which taper toward the lip 17 and which accurately position the spigot 20 relative to the socket 15. The spigot 20 comprises an upper disc 25 fixed to seat belt 13, a lower disc 27, and an annular groove 28 defined between the upper and lower discs, the groove 28 being sized and configured to engage over the lip 17 in the locking position. The inner wall 29 defining the annular groove is circular in cross-section which enables the spigot, when in the locking position, to rotate in the socket 15 about locking axis 24, thus allowing the assembly to readily accommodate, or adapt to, users of differing girths. In this example a pull strap 30 is fixed to the spigot to facilitate positioning and withdrawal of the spigot relative to the socket. When fastening the belt a user, grasping the pull strap, draws the spigot toward the socket. As the spigot is brought into initial contact with the socket, the magnetic means takes over to draw the spigot into the socket as described above. To disengage the belt a user applies a disconnecting force to the pull strap against the attractive forces of the magnets 21a and 21b, and against any tension applied by the belt, causing the annular groove 28 to displace from lip 17. Further displacement of the spigot brings the same into contact with ramp surface 18 which assists in the spigot overcoming the magnetic force holding it the socket, and thus its removal from the socket. The safety belt assembly as described herein may also include an interlock arrangement to prevent operation of the stairlift if a user is in position on the stairlift with the seat belt disconnected. Indeed, in some jurisdictions, the provision of such a facility is mandatory. This facility is provided in a stairlift having an electronic control unit (ECU) (not shown), the stairlift having an occupation sensor (not shown) and a hand control 38 but the respective natures of the ECU, the chair occupation sensor, and the hand control are well known to those skilled in the art and their respective forms are not material to this invention. As shown in Figure 4, the interlock arrangement includes a sensor 40 connected to the ECU by wires 41, the sensor 40 being configured and positioned to sense when the spigot 20 is fully engaged within the socket 15. Because of the accurate positioning of the spigot in the socket, when the spigot is in the locking position the interaction of the spigot with the socket can be maintained irrespective of the angular position of the spigot relative to the socket. This means that a relatively simple form of physical mechanical switch can be provided as the sensor. This switch is preferably mounted on a pcb, preferably an annular pcb 42 that, in turn, is mounted to the socket around the engagement axis 19. The ECU receives inputs from the sensor 40 and from the occupation sensor and is programmed to operate in the manner described above by disabling the hand control 38 however, given that it is known to provide communication between a stairlift ECU and a remote site, it is envisaged that the interlock arrangement by be switched on and off remotely if so desired. Figure 4 shows further detail of one possible construction of the assembly. This nonlimiting example shows the socket 15 being formed integrally with a mounting base 45 and being provided with a cover 46 to enclose the sensor 40 and pcb 42. The mounting base, in turn, is fixed to the chair, the fixing being preferably accommodated within seat bolster 9. While the above example shows the socket and retraction mechanism being mounted at opposed edges of the chair seating surface, embodiments may also be provided in which the retraction mechanism and socket are mounted, respectively, on the chair armrests 8 or on opposite edges of the backrest 7. Further, while the spigot is shown relatively unrestrained when the seat belt assembly is not in use, embodiments may be provided in which the spigot is engaged in a storage socket located at or adjacent to the retraction mechanism. In this event the spigot may be retained in the storage socket under tension applied by the retraction mechanism and / or under magnetic influence. It will thus be appreciated, at least in the case of the example described, that the invention provides a seat belt assembly for a stairlift which enables one-handed operation, is self-locking, automatically aligns to different user body shapes and, when in the locking position, provides a firm mechanical fixing against disengagement.

Claims

1. A seat belt assembly configured for mounting on a stairlift, the assembly comprising:a belt attached to the stairlift at a first position,a fixing mounted on the stairlift at a second position spaced from the first position; andlocking means arranged and configured between the belt and the fixing such that, in use, the belt is drawn across a user positioned on the stairlift and engaged with the fixing, wherein the locking means comprises a socket on the one hand and a spigot on the other hand, magnetic means being provided to draw the spigot into the socket, the socket and spigot being configured to allow the spigot, when engaged in the socket, to displace, to a locking position in which the spigot is mechanically retained within the socket.

2. A seat belt assembly as claimed in claim 1 wherein said belt is attached to a retraction mechanism.

3. A seat belt assembly as claimed in claim 1 or claim 2 wherein said spigot is drawn into the socket along an engagement axis and, once engaged, is drawn into the locking position in a direction substantially perpendicular to the engagement axis.

4. A seat belt assembly as claimed in claim 2 or claim 3 wherein the socket and spigot are configured such that, as the spigot engages in the socket, tension applied to the belt serves to bias the spigot toward said locking position.

5. A seat belt assembly as claimed in any one of claims 1 to 4 wherein said spigot is rotatable with respect to the socket about a locking axis when in the locking position.

6. A seat belt assembly as claimed in any one of the preceding claims wherein said socket includes a lip, and said spigot includes an annular groove that engages over the lip when in the locking position.

7. A seat belt assembly as claimed in claim 6 wherein said socket includes anentrance aperture configured to guide said spigot in the direction of said lip.

8. A seat belt assembly as claimed in claim 6 wherein said entrance aperture includes spaced edges tapering in a direction toward said lip9. A seat belt assembly as claimed in any one of the preceding claims wherein said socket includes a ramp configured to deflect the spigot in a direction out of the socket when a force is applied to remove the disengage the spigot from the locking position.

10. A seat belt assembly as claimed in any one of the preceding claims wherein the spigot is fixed to the belt.

11. A seat belt assembly as claimed in claim 10 wherein said spigot includes a pull strap projecting therefrom.

12. A seat belt assembly as claimed in any one of the preceding claims wherein the magnetic means is configured to draw the spigot toward the locking position.

13. A seat belt assembly as claimed in any one of the preceding claims wherein the magnetic means comprises a first magnet mounted on or within the socket and a second magnet of reverse polarity mounted on or within the spigot14. A seat belt assembly as claimed in claim 13 wherein the first and second magnets are offset laterally with respect to a vertical axis, upon initial engagement of said spigot in said socket but are substantially aligned when said spigot is in the locking position.

15. A stairlift chair including the seat belt assembly as claimed in any one of the preceding claims.

16. A stairlift chair as claimed in claim 15 having a seating surface, wherein said retraction mechanism is fixed at or adjacent to a side edge of said seating surface and said socket is fixed at or adjacent to an opposed side edge of said seating surface.

17. A stairlift chair as claimed in claim 15 having a pair of spaced armrests, wherein said retraction mechanism is fixed to one of said pair of armrest sand said socket is fixed to the other of said pair of armrests.

18. A stairlift chair as claimed in claim 15 having a backrest, wherein said retraction mechanism is fixed at or adjacent to a side edge of said backrest and said socket is fixed at or adjacent to an opposed side edge of said backrest.

19. A stairlift including the stairlift chair as claimed in any one of claims 15 to 18.

20. A perch-based stairlift including the seat belt assembly as claimed in any oneof claims 1 to 1421. A stand-on stairlift including the seat belt assembly as claimed in any one of claims 1 to 14.

22. A stairlift as claimed in any one of claims 19 to 21 including an electronic control unit (ECU); and a hand control and occupation sensor operatively connected to said ECU; wherein said seat belt assembly includes sensing means connected to said ECU operable to establish when said spigot is in the locking position, said ECU being configured to disable said hand control when said occupation sensor determines the presence of a user positioned on the stairlift, and said spigot is not in the locking position.

23. A stairlift as claimed in claim 22 wherein said sensing means includes a printed circuit board mounted on an annular carrier.

24. A stairlift as claimed in any of claims 19 to 23 further including a receptacle mounted adjacent to said retraction mechanism, said receptacle including means to draw said spigot into a storage position when said spigot is withdrawn from said socket.

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