When the seat unit moves over the rail system in such a stairlift, measures must be taken to prevent the stairlift colliding with objects present close to the stairlift or to prevent the seat unit running off the rail. For this purpose stops or switches can for instance be present on the extremities of the rail which can co- act with switches or stops situated on the seat unit, so that the seat unit stops when the extremity of the rail system is reached.

Particularly when the power supply for the drive of the seat unit is provided by batteries present in the seat unit, it may be important that special measures be taken to bring the seat unit to a stop in particular cases and/or to ensure that a movable rail part is situated in the correct position when the seat unit approaches that rail part. Such a movable rail part is known from W097/26207.

The invention has for its object to provide a stairlift with a seat unit and a rail system wherein the seat unit can be brought to a stop at one or more determined locations and/or wherein it is possible in efficient manner to ensure that a movable rail part is situated in the correct position.

For this purpose the rail system is provided according to the invention with a displaceable stop which can come

into contact with a part of the seat unit during the movement of the seat unit along the rail system.

The stop can herein bring the seat unit to a stop when the stop is placed in a position wherein the stop actuates a switch in the passing seat unit. When the seat unit does not have to be brought to a stop at the location in question, the stop can be displaced to a position in which the stop does not come into contact with the seat unit.

Displacement of the stop between a position in which the stop can come into contact with said part of the seat unit, i. e. the switch, and the position in which the stop is out of reach of said part can take place on the basis of an electrical signal coming from a detector which for instance detects an opened door or a determined position of a movable rail part.

The stop is preferably pressed by a spring into the position in which the stop can come into contact with the switch on the seat unit, so that this safe position in which the movement of the seat unit is stopped is occupied as long as the adjusting mechanism (electromagnet) of the stop is not energized, for instance because of power supply failure.

The stop can also be embodied such that the switch of the seat unit is only operated in a determined direction of movement of the seat unit. This will be further explained with reference to an embodiment.

Particularly when the position of the stop depends on the position of a movable rail part, there can be a mechanical connection between the displaceable stop and the movable rail part, the control mechanism of the rail part or the locking mechanism of this rail part. Thus, a

locking pin which can be inserted into a recess of the movable rail part to connect this rail part to the fixed rail of the rail system in the position in which this locking pin is not inserted in the rail part can for instance form the stop with which the above mentioned part of the seat unit collides.

In the case of a stairlift in which the rail system is provided with a fixed rail arranged along a staircase and with a movable rail part which can move between an active position in which the rail part connects onto the fixed rail and an inactive position in which this rail part causes less inconvenience, the stop is preferably connected mechanically to the movable rail part or a control mechanism thereof, so that when the rail part is in the inactive position the stop is displaced such that the stop comes into contact with said part of the seat unit when the seat unit approaches the rail part.

The stop can also be displaceable in that during the movement of the seat unit said part of the seat unit displaces the stop, wherein this part presses against the stop.

In a preferred embodiment the movable rail part can be coupled to the seat unit such that said rail part is placed into the active position when the seat unit moves toward the rail part and/or is placed into the inactive position when the seat unit moves away from the rail part. Driving of the seat unit herein results not only in movement of this seat unit but also in movement of the movable rail part. Not only does this save on a drive but also results in the movable rail part always being situated in the inactive position, wherein it causes less inconvenience, while the active position is only taken up when this is necessary for use of the rail system.

A separate makeshift arrangement with which the movable rail part can be moved manually is herein also unnecessary since the movable rail part is placed in the correct position by the approaching seat unit.

Particularly when the seat unit is not provided with batteries for the driving, the stairlift can be embodied such that in the case of a total power supply failure the seat unit can be displaced downward by means of the force of gravity, controlled by a person seated thereon, wherein the movable rail part situated on the lower extremity of the rail system is placed into its inactive position by the approaching seat unit.

The invention further relates to the rail system for the above stairlift.

The invention also relates to a method of safeguarding a stairlift provided with a rail system and a seat unit which can be moved along the rail system, wherein the drive for moving the seat unit is switched off by a stop of the rail system which comes into contact with a switch on the seat unit, wherein the stop is displaced between a position in which the stop can come into contact with said switch and a position in which the stop is out of reach of said switch.

The invention further relates to a method of moving a movable rail part of a rail system of a stairlift by means of a control mechanism, which rail system is provided with a fixed rail arranged along a staircase and with a movable rail part which can move between an active position in which the rail part connects onto the fixed rail and an inactive position in which the rail part causes less inconvenience, wherein the control mechanism carries the rail part from the inactive position into the active position due to the movement of the seat unit which is displaced along the rail system. This can take place by displacing a stop present on the control

mechanism by pushing it aside with a part of the seat unit.

The use of a displaceable stop for the purpose of bringing the seat unit to a standstill as required at one or more predetermined locations by displacing these stops into an active position can be deemed a separate invention. Moving of the movable rail part by means of the movement of the seat unit can likewise be deemed a separate invention. Displacement of the stop by mechanical connection thereof to the movable rail part or parts thereof can also be deemed a separate invention.

Further features, which can be applied separately or in combination, are described hereinbelow with reference to embodiments and are stated in the claims.

For elucidation of the invention several embodiments of a stairlift will be described with reference to the drawing.

Figures 1-3 show a first embodiment; figures 4 and 5 show a second embodiment; figure 6 shows the first embodiment in combination with a movable rail part, and figures 7 and 8 show a third embodiment.

The figures are purely schematic views of the embodiments, wherein corresponding parts are designated with the same reference numerals.

The figures show in each case the rear of a seat unit 1 which can be displaced along a rail system consisting of two round tubes 2,3. To this end the seat unit 1 is connected by means of guide member 4 to tube 2 of the rail system and by means of guide member 5 to tube 3 of the rail system. Guide members 4,5 are provided with wheels which rest against tubes 2,3 and which can be

driven in order to displace seat unit 1 along rail system 2,3. This displacement can also take place by means of a gear rack which is arranged in the rail system and which is in engagement with a rotatably driven toothed wheel arranged in the seat unit.

Driving of the seat unit can take place with external power supply, for instance with an electrical conducting wire running to the seat unit or by slide contacts which are connected to the seat unit and which displace in a stationary rail in which voltage is present. The power supply is preferably provided by one or more batteries (accumulators) present in seat unit 1.

Arranged on guide member 4 is a switch 6 with which the drive of seat unit 1 can be switched off to bring seat unit 1 to a stop. Rail system 2,3 is further provided with a displaceable stop 7 which can be displaced between the active position in which stop 7 can come into contact with switch 6 and an inactive position wherein stop 7 remains out of reach of parts of seat unit 1.

Figures 1,2,3 show a stop 7 which is pivotable on a shaft 8. Figure 1 shows the inactive position of stop 7, wherein stop 7 is displaced by means of an electromagnet 9 into a position wherein stop 7 cannot come into contact with the housing of guide member 5 on which switch 6 is arranged. The active position of stop 7 is shown in figures 2 and 3, wherein electromagnet 9 is not energized and stop 7 is displaced into the active position by means of spiral spring 10.

It will be apparent that in the situation shown in figure 1 the seat unit 1 can pass over stop 7 in both directions as indicated with arrow 11. In figure 2 seat unit 1 is situated at a location such that switch 6 is depressed by stop 7, whereby the seat cannot move in downward direction. For this purpose switch 6 operates the drive

of the seat such that only a movement in upward direction is possible as indicated with arrow 11.

The position of stop 7 shown in figure 1 is the normal position wherein the seat lift has unlimited use. This position of stop 7 is achieved by a continuous energizing of electromagnet 9. In the case of power failure, stop 7 is carried into the position shown in figure 2 by the influence of spiral spring 10. This power interruption may be the result of power supply failure, wherein it is not desirable for seat unit 1 to be able to move unhindered along rail system 2,3. Electromagnet 9 can also be operated by detection means which detect whether the path followed by seat unit 1 is free of obstacles and/or whether relevant parts of the rail system are in a position to guide seat unit 1. Figure 6 thus shows a situation wherein the lower rail part 15,16 of the rail system is displaced to a position wherein it does not connect onto the other fixed part 2,3 of the rail system.

Stop 7 herein lies in a position which prevents seat unit 1 moving further downward.

Figure 3 shows that the stop 7 pivotable on shaft 8 is embodied such that the seat unit can always pass when it is moving in upward direction, while the progress of seat unit 1 can be blocked when it moves in downward direction.

Figures 4 and 5 show an embodiment wherein stop 7 takes the form of a guide plate which can be displaced by means of electromagnet 9. A spiral spring 10 is also present herein which pushes the stop into the active position when electromagnet 9 is not energized. Switch 6 is provided with a pivot arm 12 which can come into contact with stop 7. The direction in which seat unit 1 moves can herein be detected by detecting the direction in which pivot arm 12 pivots. Blocking of seat unit 1, i. e. switch-off of the drive, can thus be limited to the

situation where seat unit 1 moves in a particular direction.

It will be apparent that a stop 7 can be arranged at one or more locations of the rail system in order to safeguard the stairlift such that the movement of the seat lift is limited or blocked when movement of the seat unit is obstructed at determined positions. Such a safety system is particularly important when the power supply for driving the seat unit is provided by batteries present in the seat unit.

Figures 6-8 show a rail system consisting of a fixed part with tubes 2,3 and a displaceable rail part comprising tubes 15,16. Tubes 2,3 are mounted on post 17 (figure 6), this post not being shown in figures 7 and 8. A swivel arm 18 consisting of two parts is further connected to movable rail part 15,16.

In figure 6 movable rail part 15,16 is shown in the inactive position, wherein this rail part is situated under the remaining part of the rail system. This may be important if the lower part of the rail system obstructs the passage of the landing present at the bottom of a staircase.

Figure 6 does not show the guide mechanism with which the upper extremity of movable rail part 15,16 is guided.

This guide mechanism can be provided with a mechanical connection to stop 7 so that stop 7 is always placed in the blocking position when the movable rail part is in the inactive position. Electromagnet 9 is herein superfluous, which may signify a simplification of the rail system.

Figures 7 and 8 show a rail system with a movable rail part 15,16, wherein this movable rail part is guided at the upper end by an endless chain 20 running over three

chain wheels 21,22,23. The upper extremity of the movable rail part is connected to chain 20 at a position indicated in figure 7 with reference numeral 24. It will be apparent that by rotation of chain wheels 21,22,23 and the associated displacement of chain 20 the movable rail part 15,16 can be guided from the inactive position shown in figure 7 to the active position shown in figure 8 and vice versa. Swivel arm 18 swivels herein.

In the embodiment of figures 7 and 8 the chain 20 is driven by means of chain wheel 23 in that a chain wheel 25 is mounted coaxially on chain wheel 23, over which chain wheel 25 runs a chain 26 which is further guided by chain wheel 27. It will be apparent that chain 20 can be displaced by chain 26 being moved. Movable rail part 15,16 can therefore be displaced from the active position to the inactive position and vice versa by moving chain 26.

This movement of chain 26 takes place in that this chain 26 is provided with two displaceable stops in the form of cams 28,29 which can co-act with a pin 30 arranged on seat unit 1.

When seat unit 1 moves downward from the position shown in figure 7, pin 7 will collide with stop 28 and then carry this stop downward. Chain 26 is hereby moved, which results in chain 20 being moved, this in a manner such that movable rail part 15,16 is carried from the inactive position into the active position (figure 8). Seat unit 1 can subsequently reach the lowest position at the bottom of staircase 31 via this movable rail part. When seat unit 1 subsequently moves upward, pin 30 will come into contact with stop 29 when seat unit 1 has left movable rail part 15,16 and will carry this stop in upward direction so that chain 26 is moved, which chain carries movable rail part 15,16 into its inactive position via chain 20.

It will be apparent that in this manner the movable rail part 15,16 always lies in its safe inactive position unless the active position is required because the seat unit must be guided by movable rail part 15,16. The necessary locking mechanisms are of course present to ensure that the movable rail part remains in the required position.

In the shown embodiment the movable rail part is guided by means of a chain 20. There are of course many other guide options, such as systems of rods or guide rails.

The driving can herein also take place by moving the seat unit.