STAIRLIFT

Abstract

The invention provides a swivel mechanism for a stairlift chair and a stairlift including such a swivel assembly. The assembly includes two swivel axes, one of which attached to the carriage and the other of which attaches to the chair. The axes are spaced and preferably geared together.

Claims

1. A swivel assembly for a stairlift chair, said swivel assembly including a first axis of rotation and a second axis of rotation substantially parallel to said first axis of rotation, said first and second axes of rotation being spaced apart in a direction substantially perpendicular to the first and second axes.

2. A swivel assembly as claimed in claim 1, wherein the swivel assembly comprises at least one shaft and at least one of said axes of rotation is defined by one of the at least one shaft.

3. A swivel assembly as claimed in claim 2, wherein: the at least one shaft comprises two shafts, each shaft defining one of said axes of rotation; and a common housing, said shafts being located in the common housing and projecting from the common housing in opposite directions.

4. A swivel assembly as claimed in claim 1, further including a transmission whereby rotation about one of said axes of rotation effects rotation about the other of said axes of rotation.

5. A stairlift chair mountable on a stairlift carriage, said chair having a swivel assembly as claimed in claim 1, wherein said swivel assembly is mountable to said carriage along said first axis and is mounted to said chair along said second axis.

6. A stairlift chair as claimed in claim 5, having a longitudinal centerline extending between front and rear edges of said chair, said second axis being fixed to said chair along said longitudinal centerline.

7. A stairlift including: a stairlift rail; a carriage mounted on said rail for movement along said rail; a chair mounted on said carriage; and a swivel assembly as claimed in claim 1 mounted between said chair and said carriage to permit said chair to swivel relative to said carriage.

8. A stairlift as claimed in claim 7, wherein said chair has a longitudinal centerline and a travel position in which said longitudinal centerline is aligned substantially perpendicular to said rail, wherein said first and second axes of rotation are arranged along said longitudinal centerline when said chair is in said travel position.

9. A stairlift as claimed in claim 7, wherein said chair has a front edge and a rear edge, said second axis being located closer to the rear edge of said chair than to said first axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] One working embodiment of the invention will now be described with reference to the accompanying drawings in which:

[0023] FIG. 1: shows a plan view of part of a stairlift installation including a swivel mechanism according to the invention;

[0024] FIG. 2: shows a side elevation of that which is shown in FIG. 1; and

[0025] FIG. 3A to 3C: show diagrammatic views of a stairlift chair swivelling between a travelling position and a swiveled embarking/dis-embarking position.

DETAILED DESCRIPTION OF WORKING EMBODIMENT

[0026] Referring to the drawings a stairlift installation is shown having a carriage 11 mounted on a rail 12. A chair 13 is mounted on the carriage via a swivel assembly 14 to enable the chair to be swivelled relative to the carriage from the normal straight-ahead travelling position shown in FIGS. 1 & 3A, in a manner that will be described in greater detail below. The chair 13 has a seat base 15, a backrest 16 and armrests 17. As can be seen in FIG. 1, the seat base 15 has a front edge 18, a rear edge 19 and a longitudinal centreline 20 extending through and between the front and rear edges.

[0027] The essence of the invention lies in the arrangement of the swivel assembly 14 which has two spaced axes of rotation. A first axis of rotation 22 defines the swivel connection between the carriage 11 and the swivel assembly 14, while a second axis of rotation 23 defines the swivel connection between the swivel assembly 14 and the chair 13. The positions of axes 22 and 23 are preferably fixed with respect to one another.

[0028] As is apparent from FIG. 2, a shaft is mounted on the axis 22 that projects downwardly from the swivel assembly 14 to engage the carriage. The chair is mounted on a rotating boss (not shown) projecting from the upper surface of the swivel assembly on axis 23. It will also be appreciated that the axes 22 and 23 are spaced apart. When the chair is in the normal travel position shown in FIGS. 1 and 3A, both axes 22 and 23 preferably lie substantially on the longitudinal centreline 20 of the chair but the axis 23 is closer to the rear edge 19 of the chair, than the axis 22.

[0029] The swivel assembly 14 preferably further includes a form of transmission between the two axes 22 and 23 so that rotation around one of the axes effects rotation about the other. In the form shown this transmission comprises a gear 24 mounted on the axis 22, a gear 25 mounted on the axis 23 and an idler gear 26 located between, and in mesh with, the gears 24 and 25. The gears 24, 25 and 26 may be mounted in a housing 27 that is located between and attaches to, both the carriage 11 and the chair 13, the shaft defining axis 22 projecting below the housing 27 and the rotating boss on axis 23 projecting from the upper surface of the housing 27.

[0030] Turning now to FIGS. 3A to 3C, the chair is shown swivelling between the conventional travelling position shown in FIG. 3A and the fully-swivelled position shown in FIG. 3C. In order to understand the invention, it is convenient to observe the movement of the longitudinal centreline 20 of the chair relative to a reference axis 30 which is perpendicular to the line of the rail 12 and passes through the first axis of rotation 22.

[0031] When the chair 13 is in the normal travel position, the centreline 20 overlies the reference axis 30. When gear 24 is rotated in a clockwise direction, the gear 25 is also rotated in a clockwise direction causing the chair to swivel to the left as shown in FIGS. 3B and 3C. It will be seen that, as the chair is swivelled, the backrest 16 is drawn away from wall 31 thus overcoming a major problem experienced when the chair is mounted on its centreline, namely the backrest colliding with the wall. It will also be seen that, when swivelled, the chair is displaced a distance x from the reference axis which eases entry to, and exit from, the chair at the end of the rail.

[0032] The arrangement shown in FIGS. 3A to 3C is appropriate for swivelling at the bottom of the rail 12. At the top of the rail, the gear 24 would be rotated in a counter-clockwise direction, causing the chair 13 to be swivelled in the opposite direction.

[0033] It will be appreciated that, by changing the ratio of the gearing between the gears 24 and 25, and by changing the spacing between the axis 22 and 23, the available swivel angle and seat projection, when swivelled, can be varied.