DRIVE UNIT

Abstract

A drive unit for a rail-guided displacement device comprising: a base part; a housing comprising: a first yoke shaft sleeve and a second yoke shaft sleeve, the first yoke shaft sleeve and the second yoke shaft sleeve being spaced apart and disposed on opposite sides of the base part, and a cross sleeve rigidly connecting the first yoke shaft sleeve and the second yoke shaft sleeve; wherein the housing is pivotally connected to the base part such that the housing can pivot, in use, relative to the base part about a pivot axis; a first yoke and a second yoke, each of the first yoke and the second yoke comprising: a guide wheel assembly, the guide wheel assembly comprising one or more guide wheels arranged to roll, in use, along a running rail; and a yoke shaft; wherein the yoke shaft of the first yoke is received in the first yoke sleeve and the yoke shaft of the second yoke is received in the second yoke sleeve, the yoke shafts being movable longitudinally within their respective yoke sleeve, in use; and a communication means disposed at least partially within the cross sleeve, the communication means providing communication between the yoke shafts in the yoke sleeves and being configured such that when, in use, one of the yoke shafts moves longitudinally in its yoke sleeve the communication means causes the other of the yoke shafts correspondingly to move longitudinally in its yoke sleeve.

Claims

1. A drive unit for a rail-guided displacement device comprising: a base part; a housing comprising: a first yoke shaft sleeve and a second yoke shaft sleeve, the first yoke shaft sleeve and the second yoke shaft sleeve being spaced apart and disposed on opposite sides of the base part, and a cross sleeve rigidly connecting the first yoke shaft sleeve and the second yoke shaft sleeve; wherein the housing is pivotally connected to the base part such that the housing can pivot, in use, relative to the base part about a pivot axis; a first yoke and a second yoke, each of the first yoke and the second yoke comprising: a guide wheel assembly, the guide wheel assembly comprising one or more guide wheels arranged to roll, in use, along a running rail; and a yoke shaft; wherein the yoke shaft of the first yoke is received in the first yoke sleeve and the yoke shaft of the second yoke is received in the second yoke sleeve, the yoke shafts being movable longitudinally within their respective yoke sleeve, in use; and a communication means disposed at least partially within the cross sleeve, the communication means providing communication between the yoke shafts in the yoke sleeves and being configured such that when, in use, one of the yoke shafts moves longitudinally in its yoke sleeve the communication means causes the other of the yoke shafts correspondingly to move longitudinally in its yoke sleeve.

2. The drive unit according to claim 1, wherein the communication means comprises a mechanical mirror shaft configured to engage with the yoke shafts, optionally wherein the mechanical mirror shaft engages with the yoke shafts such that longitudinal movement of the yoke shafts within the yoke shaft sleeves causes rotational movement of the mechanical mirror shaft.

3. (canceled)

4. The drive unit according to claim 1, wherein the pivot axis is offset from the longitudinal axis of the cross sleeve.

5. The drive unit according to claim 1, wherein central longitudinal axes of the yoke shafts are parallel with each other and extend substantially perpendicularly to a plane containing the pivot axis and the longitudinal axis of the cross sleeve, optionally wherein the central longitudinal axes of the yoke shafts intersect a plane containing the pivot axis and the longitudinal axis of the cross sleeve.

6. (canceled)

7. The drive unit according to claim 1, wherein each guide wheel assembly is pivotable relative to its respective yoke.

8. The drive unit according to claim 1, wherein each yoke comprises an open jaw having the guide wheel assembly mounted therein.

9. The drive unit according to claim 1 comprising at least one sensor operable to measure the relative angle of the housing to the base part.

10. The drive unit according to claim 1 comprising at least one sensor operable to measure, directly or indirectly, longitudinal movement of each yoke shaft within its respective yoke shaft sleeve.

11. The drive unit according to claim 1 comprising a drive means operable to move, in use, the drive unit along a running rail, and optionally comprising a sensor arranged to measure and/or monitor operation of the drive means.

12. (canceled)

13. A rail-guided displacement device comprising a drive unit according to claim 1 and a support platform attached to the base part of the drive unit, optionally wherein the support platform comprises a chair or a seat.

14. (canceled)

15. The rail-guided displacement device according to claim 13 comprising an inclinometer coupled to the support platform.

16. A rail-guided displacement device system comprising: a running rail; a rail-guided displacement device according to claim 13, claim 14 or claim 15 on the running rail; and a control system operable to control travel of the rail-guided displacement device along the running rail.

17. The rail-guided displacement device system according to claim 16 comprising a single running rail.

18. The rail-guided displacement device system according to claim 16, wherein the rail-guided displacement device system is a stair lift system, optionally wherein the running rail is configured at an end to provide a first step start.

19. (canceled)

20. The rail-guided displacement device system according to claim 16, wherein the control system controls travel of the rail-guided displacement device in response to signals received from one or more sensors in or on the drive unit.

21. The rail-guided displacement device system according to claim 16, wherein the control system comprises a level control system operable to hold the support platform level as the rail-guided displacement device moves along the running rail.

22. The rail-guided displacement device system according to claim 16, wherein the control system is operable to vary the speed of the rail-guided displacement device as the rail-guided displacement device moves along the running rail.

23. A method of installing a rail-guided displacement device system at an intended site of use, the method comprising: mounting a drive unit according to claim 1 on a running rail; and installing a control system operable to control travel of the rail-guided displacement device along the running rail.

24. The method according to claim 23 including the step of fixing the running rail in place at the intended site of use, and optionally wherein the intended site of use comprises at least one staircase.

25. (canceled)

26. The method according to claim 23, further comprising the step of attaching a support platform to the base

Description

[0053] In order that the invention can be well understood, certain embodiments will be described by way of example only with reference to the accompanying drawings, in which:

[0054] FIG. 1 shows an example embodiment of a drive unit for a stair lift according to the invention;

[0055] FIG. 2 shows in more detail and partially cut away, the housing and yokes of the drive unit shown in FIG. 1;

[0056] FIG. 3 is a side elevation of the drive unit of FIG. 1;

[0057] FIG. 4 illustrates schematically a drive unit according to the invention traversing a climbing bend; and

[0058] FIG. 5 illustrates schematically a drive unit according to the invention traversing a flat bend.

[0059] FIGS. 1 and 3 show a drive unit 1 according to an example embodiment of the invention. The drive unit 1 is adapted for use with a single running rail (not shown), typically of round cross-section, running alongside a staircase.

[0060] The drive unit 1 comprises a base part 2. The base part 2 has a rear portion and a front portion with an intermediate cross portion extending between the rear portion and the front portion. In the rear portion of the base part 2, there is a gear box housing 18 containing a gear box. The gear box is coupled to a motor 17, typically an electric motor. The motor is located above the gear box housing 18. Below the gear box, at the bottom of the base part 2 is a pinion 19. The pinion 19 is coupled to the gear box and hence the motor. The pinion 19 is configured to engage with a rack (not shown) arranged below the running rail. Together, the motor, gear box and pinion 19 provide a drive means operable to move, in use, the drive unit 1 along the running rail. Located between gear box housing 18 and the pinion 19 is a central guide wheel 24, configured to roll, in use, along the running rail. A sensor such as a motor encoder 16 is coupled to the motor and is operable to measure rotation of the motor. Alternatively, the sensor coupled to the motor and operable to measure rotation of the motor may comprise a potentiometer. A data link (not shown) is provided to carry data from the motor encoder 16 to a control system (not shown). A connector (not shown) is provided for connecting the motor to a power supply (not shown).

[0061] The front portion of the base part 2 is provided with means such as a socket 25 for securing a support surface or platform (not shown) such as a seat or chair to the drive unit 1. A means for maintaining the support surface in a horizontal orientation during travel may be provided. The means for maintaining the support surface in a horizontal orientation during travel may comprise an inclinometer.

[0062] The drive unit 1 further comprises a housing 3, which is pivotally connected to the base part 2. The parts of the housing 3 are shown particularly clearly in FIG. 2, as well as in FIGS. 1 and 3.

[0063] The housing 3 comprises a pair of elongate yoke shaft sleeves 4a, 4b, disposed on opposite sides of the base part 2. The elongate yoke shaft sleeves 4a, 4b have parallel longitudinal axes. A cross sleeve 5 rigidly connects the elongate yoke shaft sleeves 4a, 4b to each other. The cross sleeve 5 extends perpendicularly to the longitudinal axes of the yoke shaft sleeves 4a, 4b. The cross sleeve 5 passes over the intermediate cross portion and between the rear portion and the front portion of the base part 2.

[0064] The housing 3 is pivotally connected to the base part 2 at a pair of pivot points 6a, 6b, located on opposite sides of the base part 2. In use, the housing 3 pivots relative to the base part 2 about a pivot axis 7, which passes through pivot points 6a, 6b. A pivot encoder 14 is provided to measure rotation about the pivot axis 7. A data link (not shown) is provided to carry data from the pivot encoder 14 to a control system (not shown). It will be appreciated that the pivot encoder 14 is an example of a sensor that could be employed to measure rotation about the pivot axis 7. An alternative sensor could comprise a potentiometer.

[0065] The cross sleeve 5 contains a mechanical mirror shaft (not shown), which has at each end a gear 23a. A mechanical mirror shaft encoder 15 is provided to measure rotation of the mechanical mirror shaft about a longitudinal axis 8 of the cross sleeve 5. A data link (not shown) is provided to carry data from the mechanical mirror shaft encoder 15 to a control system (not shown). It will be appreciated that the mechanical mirror shaft encoder 15 is an example of a sensor that could be employed to measure rotation of the mechanical mirror shaft about a longitudinal axis 8 of the cross sleeve 5. An alternative sensor could comprise a potentiometer.

[0066] Each yoke shaft sleeve 4a, 4b is adapted to receive a yoke shaft 13a, 13b of a yoke 9a, 9b.

[0067] Each yoke 9a, 9b comprises an open jaw portion 10a, 10b, in which is pivotally mounted a guide wheel assembly 11a, 11b comprising a plurality of yoke guide wheels 12a, 12b. The yoke guide wheels 12a, 12b are arranged to roll, in use, along the running rail. Each guide wheel assembly 11a, 11b is pivotally mounted in its respective open jaw portion 10a, 10b such that, in use, the guide wheel assembly 11a, 11b will remain perpendicular to the running rail.

[0068] The drive unit 1 is configured such that the running rail (not shown) passes, in use, through the open jaw portions 10a, 10b of the yokes 9a, 9b disposed on opposite sides of the base part 2 and beneath the cross portion of the base part 2. Thus, the yoke guide wheels 12a, 12b and the central guide wheel 24, which is located between the yokes 9a, 9b, run along the running rail, in use.

[0069] The yoke shaft 13a, 13b of each yoke 9a, 9b extends away from the open jaw portion 10a, 10b and passes through the yoke shaft sleeve 4a, 4b. Each yoke shaft 13a, 13b is movable, in use, longitudinally within the yoke shaft sleeve 4a, 4b, in which the yoke shaft sleeve 13a, 13b is received. Central longitudinal axes 20a, 20b of the yoke shafts 13a, 13b are indicated in the drawings. The yoke shafts 13a, 13b can move longitudinally within the yoke shaft sleeves 4a, 4b.

[0070] As shown in FIG. 2, the yoke shaft 13a has a toothed portion 22a located in an intermediate region of the yoke shaft 13a. The toothed portion 22a engages with the gear 23a at the end of the mechanical mirror shaft. The other yoke shaft 13b also has a toothed portion (not shown) located in an intermediate region of the yoke shaft 13b. The toothed portion engages with a gear (not shown) at the respective end of the mechanical mirror shaft.

[0071] The engagement between toothed portions on the yoke shafts 13a, 13b and the gears on the mechanical mirror shaft mean that the mechanical mirror shaft rotates as the yoke shafts 13a, 13b move longitudinally in their respective yoke shaft sleeves 4a, 4b. The rotation of the mechanical mirror shaft is measured, in use, by the mechanical mirror shaft encoder 15. From this measurement, the position of the yoke shafts 13a, 13b in their respective yoke shaft sleeves 4a, 4b can be inferred. The mechanical mirror shaft acts to ensure that when one yoke shaft moves, the other yoke shaft also moves.

[0072] As can be seen in FIG. 1, the pivot axis 7 is offset from the longitudinal axis 8 of the cross sleeve 5. Such an offset is not required for proper functioning of the drive unit 1, i.e. the pivot axis 7 and the longitudinal axis 8 of the cross sleeve 5 may not be offset from each other. The central longitudinal axes 20a, 20b of the yoke shafts 13a, 13b are parallel with each other and extend perpendicularly to a plane containing the pivot axis 7 and the longitudinal axis 8 of the cross sleeve 5. The central longitudinal axes 20a, 20b of the yoke shafts 13a, 13b intersect the plane containing the pivot axis 7 and the longitudinal axis 8 of the cross sleeve 5 between the pivot axis 7 and the longitudinal axis 8 of the cross sleeve 5.

[0073] By pivoting about the pivot axis 7, in use, the housing 3 moves through a housing swing arc 21a. As a consequence, the yokes 9a, 9b, move, in use, through a yoke swing arc 21b.

[0074] The combination of a swing motion and longitudinal movement of the connected yoke shafts enables the drive unit to traverse, in use, a running rail having any combination of types of bend.

[0075] FIG. 4 shows schematically a side view of a drive unit according to the invention traversing a climbing bend 48 in a running rail. The climbing bend 48 is between a horizontal section 40 of the running rail and a sloping section 41 of the running rail.

[0076] The drive unit is travelling in the direction indicated by the arrow 42. Shown schematically is a base part 43 of a drive unit between a leading yoke 44a with a yoke shaft 45a and a following yoke 44b with a yoke shaft 45b. Longitudinal movement of the yoke shafts 45a, 45b within the yoke shaft sleeves is indicated by the double headed arrows 46a, 46b. Each yoke 44a, 44b has a guide wheel assembly 47a, 47b pivotally connected thereto. As can be seen in FIG. 4, the guide wheel assemblies 47a, 47b pivot relative to their respective yokes 44a, 44b such that the guide wheel assemblies 47a, 47b remain perpendicular to the running rail as the drive unit traverses the climbing bend 48.

[0077] FIG. 5 shows schematically a plan view of a drive unit according to the invention traversing a flat bend 57 in a running rail. The flat bend 57 is between a first section 50 of the running rail and a second section 51 of the running rail, the second section 51 of the running rail extending in a different direction from the first section 50 of the running rail. The drive unit is travelling in the direction indicated by the arrow 52. Shown schematically is a base part 53 of a drive unit between a leading yoke 54a with a yoke shaft 55a and a following yoke 54b with a yoke shaft 55b. Swing movement of the yoke shafts 55a, 55b is indicated by the arrows 56a, 56b.

[0078] A stair lift system may comprise a drive unit according to the present invention. In such a stair lift system, the drive unit may be coupled to a support platform such as a seat or a chair. The stair lift system may comprise a running rail. The stair lift system may comprise a control system in communication with the drive unit and operable to control movement of the drive unit along the running rail. In particular, one or more sensors (e.g. encoders or potentiometers) on the drive unit may be in communication with the control system.

[0079] Conveniently, the drive unit of the present invention can be used with a running rail that is configured for a first step start. In a first step start configuration, the running rail typically comprises a vertical section adjacent a first step of a staircase. Having a running rail that is configured for a first step start may be particularly beneficial in stair lift systems installed on staircases in relatively confined spaces.

[0080] An example of the operation of the drive unit 1, or a stair lift system comprising the drive unit 1, will now be described.

[0081] The yoke guide wheels 12a, 12b of the guide wheel assemblies 11a, 11b mounted in the yokes 9a, 9b provide a connection with the running rail either side of the base part 2 of the drive unit 1. As described above, the yokes 9a, 9b are connected together via the toothed portions of yoke shafts 13a, 13b engaging with the gears on the mechanical mirror shaft. Accordingly, a mechanical mirror is formed, which causes, in use, both yokes 9a, 9b to move together when the drive unit enters a climbing bend (or a bend comprising a climbing component).

[0082] In the climbing bend, the angle of rotation of the mechanical mirror shaft inside the cross sleeve 5 is dependent upon the rate of change of the gradient of the running rail. This gradient is inferred from readings taken by the mechanical mirror shaft encoder 15. Consequently, the control system is provided with the instantaneous rate of change of the gradient of the running rail.

[0083] As described above, the housing 3 is pivotally connected to the base part 2, which allows the drive unit 1 to negotiate flat bends (or bends comprising a flat bend component). In a flat bend, the swing angle between the housing 3 and the base part 2 is dependent upon the rate of change of direction (horizontal angle) of the running rail. The pivot encoder 14 measures the angle of the housing 3 relative to the base part 2. Consequently, the control system is provided with the instantaneous rate of change of the direction (horizontal angle) of the running rail.

[0084] In addition, the motor encoder 16 is operable to provide the control system with measurements of the rotation of the motor, from which the distance travelled along the running rail can be inferred.

[0085] A support platform such as a seat or chair typically may be coupled to the drive unit. In use, the support platform may be kept in a substantially horizontal orientation. For instance, a chair may be attached to the drive unit on a horizontal axis of rotation.

[0086] Means to tilt the chair about the horizontal axis, in use, may be provided to tilt the chair such that the chair remains substantially horizontal to the ground as the gradient of the running rail changes.

[0087] An inclinometer may be coupled to the chair and may be in communication with the control system. Accordingly, the control system may use data received from the inclinometer to determine, in use, the angle of the chair to the horizontal.

[0088] In some embodiments, the stair lift system may comprise a level control system operable to hold the support platform, e.g. seat or chair, horizontal as the drive unit moves along the rail and the gradient of the rail changes with respect to the horizontal.

[0089] For instance, the level control system may be configured to integrate the output of the mechanical mirror shaft encoder 15. The integrated value may then provide a demand proportional to the angular rotation of the support platform, e.g. seat or chair, about the horizontal axis required to maintain the support platform in a substantially horizontal position.

[0090] In embodiments comprising an inclinometer, the output of the inclinometer may be used to recalibrate the stair lift system against long-term drift. The inclinometer may be monitored by the control system during operation. The control system may be configured to shut down the stair lift system and/or issue an alarm or warning message in the event that the inclinometer detects that the support platform, e.g. seat or chair, is no longer level (i.e. in a substantially horizontal position).

[0091] By receiving data from the mechanical mirror shaft encoder 15, the pivot encoder 14 and, optionally, the motor encoder 16, the control system may determine in real-time where on the running rail the drive unit 1 is located. Accordingly, there may be no need to pre-program and/or memory map the drive unit and control system for a given running rail when installing a stair lift system according to the invention.

[0092] The control system may be operable to establish the positions of the ends of the running rail. The output of the sensors (e.g. comprising encoders or potentiometers) measuring the angle of the housing relative to the base part and the rotation of the mechanical mirror shaft may be monitored by the control system to determine in real-time the position of bends in the running rail. In response, the control system may be operable to vary the speed of travel of the drive unit as it travels along the running rail, e.g. to implement a speed decrease as the drive unit enters a bend and/or to implement a speed increase as the drive unit exits a bend.

[0093] A number of modifications and variations will be apparent to the skilled person, and the foregoing examples are not intended to limit the invention, which should be determined with reference to the appended claims.