Elevator – industrial lift truck – or stationary lift for vehicle – Stationary lift for roadway vehicle or required component... – Having specific drive means for support
Patent
1993-04-19
1994-03-08
Dayoan, D. Glenn
Elevator, industrial lift truck, or stationary lift for vehicle
Stationary lift for roadway vehicle or required component...
Having specific drive means for support
414921, B66B 908
Patent
active
052919714
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a platform mechanism for a stair-lift. A stair-lift generally comprises a rail which is mounted on a stair-case or on an adjacent wall and which carries a carriage with a chair or a platform for a wheel-chair to enable an infirm person to be carried up and down the stairs. If the stairs consist of one straight flight fabrication of the stair-lift is relatively straight forward. If the carriage is to negotiate curves, however, fabrication of the stair-lift becomes more complex and expensive.
Frequently stair-cases consist of a major flight turning through 90 degrees near the upper level through winders or a quarter landing to one or two further steps. In this configuration a straight stair-lift cannot serve the upper landing level directly and it is necessary to accept the greater cost of a curved stair-lift to achieve this.
One solution to the problem is to provide a hinged platform at the upper level. The platform may be hinged up to a parked position in order not to obstruct the stair-case. When the stair-lift is at or near the upper level the platform is swung down to form a bridge. The platform may be operated manually but this is difficult for a person seated on the stair-lift. If the platform is left down when the stair-lift descends it obstructs the stair-case and presents a serious hazard because someone may inadvertently step off the unprotected edge.
The problems can be overcome by providing powered operation for the platform, operated by push-button or automatically. However, the additional motor drive mechanism and control system is expensive. The present invention seeks to provide an improvement.
SUMMARY OF THE INVENTION
According to the invention there is provided a mechanism for a stair-lift platform, there being a stair-lift carriage which runs up and down a flight of stairs and a platform which forms a bridge to the carriage at the top of the stairs, the platform being lowered so as to constitute the bridge and raised out of the way when the carriage descends, the mechanism comprising a coupling unit fixed with respect to the stairs, a linkage from the coupling unit to the platform and a pick-up on the carriage, the pick-up engaging the coupling unit so as to cause a following movement of the coupling unit with respect to the carriage, which following movement causes the platform to be raised and lowered via the linkage.
Preferably the coupling unit is of limited extent and is mounted near the top of the stairs, the pick-up engaging therewith when the carriage is near the top of the stairs and disengaging therefrom otherwise.
Preferably the coupling unit comprises a continuous chain or belt running around upper and lower wheels or pulleys, the pick-up engaging with one or more lugs or the like on a run of the chain or belt. The linkage may comprise a wire rolled around a take-up spool coupled to one of the wheels or pulleys. Preferably, however, the linkage comprises a wire or the like fixed at one end to the chain or belt at such a position as to be drawn down to raise the platform by downward movement of the carriage so as first to pass around the center of the lower wheel or pulley with the platform raised to its uppermost position. This forms an over-center movement which securely locates the platform in its upper-most position.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will further be described with reference to the accompanying drawings, of which:
FIGS. 1 to 4 are respective diagrams of a stair-lift incorporating a mechanism according to the invention with the carriage of the lift in progressive stages of descent.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 there is shown a stair-lift which comprises a chair 1 mounted on a carriage 2 which runs on a rail 3 up and down a flight of stairs (not shown). At the top of the stairs is a platform 4 hinged at 5 which forms a bridge between the chair and a landing (not shown). When the chair is at the top of the stairs it is necessary for the platform
REFERENCES:
patent: 5072810 (1991-12-01), Theis
patent: 5125481 (1992-06-01), Shibata
patent: 5230288 (1993-07-01), Bickel
Dayoan D. Glenn
Reichard Dean A.
Stannah Stairlifts Limited
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