STAIRLIFT

Abstract

 The invention relates to a stairlift comprising a rail (10) for mounting along a stairway, a platform (12) which is movably mounted on the rail (10) and a drive mechanism (14, 15, 16, 26, 27, 28) for moving the platform (12) along the rail (10), wherein the platform (12) is mounted so as to be rotateable about a vertical axis (18), characterized in that the platform (12) is further mounted so as to be tiltable about a horizontal axis (19) such that it can be tilted out of a horizontal orientation into a tilted orientation.

Description

[0001] The invention relates to a stairlift. A stairlift is a solution for the transport of sitting persons or things in places where there is, for example, no room for a normal lift shaft.

[0002] An example of a stairlift is described in US patent 5 533 594. Known stairlifts comprise a rail, which is mounted above the stairway on the inner or outer wall of the stairwell, a platform (for instance a chair, or a floor for, for instance, a wheelchair) and a first drive mechanism for moving the platform along the rail and thereby along the stairway. It is further known to provide a second drive mechanism to keep the platform horizontal, which is known in the field by the term "levelling". This second drive mechanism rotates the platform about a horizontal axis or shaft relative to the rail, depending on variations of the gradient of the rail.

[0003] Above-mentioned US patent 5 533 594 describes how, during getting on and getting off, use is also made of the rotation of the platform about a vertical axis or shaft, which is known in this field by the term "swiveling". To effect this vertical rotation, the platform is driven by a third drive mechanism. In this manner, the transported person is turned to the respective landing at the top and bottom of the stairway. For this, two positions are needed (for the top and the bottom of the stairway, respectively) which are mutually rotated relative to the rail through 180 degrees. En route, the platform is fixed in a transport position, which is, for instance, midway between the two positions for getting off, with the transported person facing the wall. It is described that for swiveling, use can be made of a combined rotation and translation movement to prevent the platform on the stairlift from hitting the wall during the swiveling from the positions for getting on and getting off to the transport position.

[0004] It is one of the objects of the invention to provide a stairlift which can be placed in stairwells, i.e. on a stairway, with bends, and which makes efficient use of the available headroom.

[0005] The invention provides a stairlift according to claim 1 and a method for moving the stairlift according to claim 9. According to the invention, the stairlift comprises a rail for mounting along a stairway, a platform which is movably mounted on the rail, and a drive mechanism for moving the platform along the rail, wherein the platform is mounted so as to be movable about a vertical axis, wherein the platform is further mounted so as to be tiltable about a horizontal axis such that it can be tilted out of a horizontal orientation into a tilted orientation.

[0006] According to the invention there is further provided a method for driving a platform along a rail mounted on a stairway comprising the steps of automatically rotating the platform about a vertical axis or shaft during the movement of the platform along the rail, and automatically tilting the platform about a horizontal axis or shaft before or during movement of the platform such that the platform is tilted out of a horizontal orientation into a tilted orientation.

[0007] According to the invention, it is effectively possible to avoid collisions for example with obstacles in the vicinity of the head of the user of a stairlift, as by tilting the platform the distance between the rail (or the staircase) and the head of a user can be reduced. For example, when passing a bulkhead of a staircase, the danger of a user colliding with the bulkhead can be minimised or completely avoided.

[0008] Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0009] Advantageously, the tilted orientation is such that a side of the platform facing in the upward direction of the stairway is lower than a side of the platform facing in the downward direction of the stairway.

[0010] Expediently, the platform is adapted such that the tilted orientation is within a range of 0° - +/- 20°, in particular between 0° - +/-15° with respect to the horizontal orientation.

[0011] According to a preferred embodiment, the platform is adapted to be moved along the rail while or after being tilted into the tilted orientation, and/or while or after being rotated.

[0012] This allows fast and effective movement along a staircase. Especially the possibility of providing a tilting of the platform together with a rotation about a vertical axis, and moving the platform in such a tilted and rotated orientation allows efficient navigation through potentially problematic sections of a stairwell.

[0013] According to a preferred embodiment, the stairlift comprises at least one collision sensor for sensing obstacles in the path or vicinity of the platform and a control device for controlling movement of the platform in dependence on signals received from the at least one collision sensor, wherein the control device is adapted to effect a tilt of the platform about the horizontal axis and/or a swivel of the platform about the vertical axis in the vicinity of obstacles.

[0014] According to a preferred embodiment the drive mechanism for moving the platform along the rail comprises a first motor, a second motor being provided which is adapted to maintain the platform in a horizontal orientation, a third motor being provided which is adapted to rotate the platform about a vertical axis or shaft and a fourth motor being provided which is adapted to tilt the platform out of its horizontal orientation into a tilted orientation. By means of such a combination of motors, space requirements for a stairlift can be minimized, and at the same time highest safety standarts can be met.

[0015] Especially, by separating the motors for maintaining the platform in a horizontal orientation (levelling) and for tilting the platform out of its horizontal orientation, especially so that the platform can be moved along the rail in said tilted orientation, highest safety standards can be met. For example, even if the fourth motor adapted to tilt the platform out of its horizontal orientation malfunctions, a levelling of the platform by means of the second motor is still possible, ensuring a limited service of the stairlift.

[0016] Be it noted that it is also possible within the scope of the invention to effect the levelling of the platform as well as the tilting of the platform by means of only one motor, i.e. by combining the second and fourth motors to one single motor.

[0017] According to a preferred embodiment, the fourth motor adapted to tilt the platform out of its horizontal orientation is positioned above the third motor adapted to rotate the platform about a vertical axis. The term "above" as used herein, can either mean directly above the third motor, i.e. also on the vertical axis, or slightly displaced from the vertical axis. In other words, in case of a normal positioning of the platform, i.e. without any tilting, the fourth motor will be positioned further away from the rail that the third motor.

[0018] The invention will now be further described with reference to the following drawings, in which

Figure 1 shows a schematically simplified side view of a stairlift according to a first embodiment of the invention, in a more detailed horizontal position, and a further simplified tilted position.

Figure 2 shows a preferred embodiment of a control system for use with the invention, and

Figure 3 shows a top plan view of a staircase, on which a stairlift according to the invention has been mounted.

[0019] Fig. 1 and Fig 3 show a stairlift, with a rail 10 mounted along a stairway 8, and a platform 12 moveably mounted on rail 10. In Figure 1, platform 12 is a chair. It will be clear that, in the framework of the invention, the term "platform" is to be understood in a general sense as any structure with a supporting surface, without necessarily being limited to a surface. In the following description, platform 12 is provided as a chair, especially comprising a seat 12a and a backrest 12b.

[0020] A first motor 14 serves to drive the platform 12 along rail-10. First motor 14 is, for instance, provided with a gear wheel (not shown) in a manner known per se and rail 10 is provided with a row of teeth (not shown) with which the gear wheel engages, so that, upon rotation of first motor 14, platform 12 moves up or down along rail 10. In this manner, platform 12 is always supported by essentially one point on rail 10, so that, without further measures, the orientation of platform 12 would follow the orientation of the rail at the location of the supporting point, as will be explained further below.

[0021] Further, the stairlift is preferably provided with a second motor 16, which serves to maintain platform 12, especially a seat 12a of platform 12, in case platform 12 is provided as a chair, horizontal. The second motor 16 serves to rotate the platform about a horizontal shaft or axis 19. The rotation about this shaft 19 compensates for the effect of changes in the gradient of rail 10 ("leveling"). Instead of a second motor, a mechanical transmission may also be used for this purpose as a second drive mechanism, so that this rotation is driven by the movement along rail 10.

[0022] A third motor 15 serves to rotate platform 12 relative to rail 10 about a vertical axis or shaft 18 ("swivelling"). Platform 12 is arranged rotationally about vertical shaft 18, for instance on a bearing (not shown), and third motor 15 drives a rotational movement about this shaft. Any form of transmission can be used, for instance by providing the shaft of third motor 15 to act directly onto a rotary shaft of platform 12, or by means of a gear wheel transmission, etc.

[0023] A fourth motor 21 is adapted to tilt the platform, especially the seat 12a of platform 12, such that a distance 11 between the backrest 12b of platform 12 and rail 10 is reduced. Expediently, this tilting is effected about a further horizontal axis (not explicitly show in the figures. Such a tilted orientation of platform 12, in which this distance 11 is reduced, is indicated schematically in dashed lines in Figure 1, for a position of platform 12 more towards the upper end of rail 10.

[0024] As can immediately be seen from Figure 1, platform 12 in this tilted orientation can pass by an obstacle 17 above rail 10, as distance 11 for this tilted orientation is smaller than minimum distance 13 of obstacle 17 in relation to rail 11. In the horizontal position of platform 12 in the first mode of operation, a collision between platform 12 and obstacle 17 would occur. This movement of platform 12 in the tilted orientation is especially advantageous if obstacle 17 is a bulkhead, i.e. the edge of an opening in a ceiling through which platform 12 passes.

[0025] Obviously, in reality, this somewhat simplified explanation would take into consideration the torso and head of a passenger seated on seat 12a of platform 12.

[0026] As can be seen from figure 1, the fourth motor 21 is located above third motor 15. The tilting movement is expediently effected about a horizontal axis extending laterally with respect to the platform, such that a passenger seated on the platform will experience a tilting movement only in the backward direction, i.e. in the reclining direction of backrest 12b. Such an axis is schematically shown and designated 39 in figure 3.

[0027] Fig. 2 shows a control system for the stairlift. The control system comprises a microcontroller 20, a memory 22, a rotation sensor 24a, at least one obstacle sensing collision sensor 24b (also shown in Fig. 1) and first, second,third and fourth motor power supplies 26, 28, 27, 29. Microcontroller 20 is coupled to memory 22, rotation sensor 24a, collision sensor 24b and first, second, third and fourth motor power supplies26, 28, 27, 29. First, second, third and fourth motor power supplies 26, 28, 27, 29 respectively drive first motor 14, second motor 16, third motor 15 and fourth motor 21.

[0028] Memory 22 contains information representing desired angles of rotation of platform 12 about vertical shaft 18 and angles of tilting. Any form of representation can be used, such as a look-up table in which desired angle values are stored for a number of positions along the rail (for instance represented by the number of rotations of first motor 14 before this position is reached), or coefficients of a polynomial representing the desired angle values as a function of the position along the rail (number of rotations of first motor 14).

[0029] Microcontroller 20 is programmed to activate first motor 14 when platform 12 is to be moved along rail 10 upstairs or downstairs. A sensor (not shown) records the number of rotations of first motor 14. The position of platform 12 along rail 10 follows from this information. Microcontroller 20 reads this sensor information and then determines desired rotating (swivelling) and tilting angles for platform 12 on the basis of this sensor information and the information in memory 22.

[0030] Any suitable form of determination of the swivelling and tilting angles on the basis of sensor information and information from memory 22 can be used. This, for instance, takes place by using the sensor information as an address in memory 22 in order to thus read out the desired angle, or by interpolation between angle values for approximate sensor values for which angle values are stored in the memory, or by calculation on the basis of stored coefficients (read-out information can be determined for different positions of platform 12; in this case, it is not necessary to read out information from memory 22 for each sensor value).

[0031] Microcontroller 20 then controls third and fourth motors 15, 21 if necessary to make third and fourth motors 15, 21 make platform 12 rotate to the swivelling and/or tilting angle desired for the position reached along rail 10.

[0032] At the same time, second motor 16 is also controlled, for example to keep level seat 12a of platform 12 in positions along rail 10, in which no tilting is required.

[0033] The information in memory 22 is chosen such that collisions are prevented between platform 12 and walls or ceiling, especially the bulkhead, of the stairwell in which the stairlift is arranged, and/or steps of the stairway. Also, if necessary, the information is chosen such that sufficient headroom is left in the stairwell during movement along rail 10. It is further possible to change the angle en route such that it allows the required rotation to the position for getting on and off at the end of the stairway.

[0034] Fig. 3 shows a top plan view of a stairwell, with a stairlift therein. The stairwell has walls 30a-d, and steps 32. Platform 12 is shown at two positions along rail 10, where it makes different angles phi relative to rail 10. The stairway makes an angle of 90 degrees. In the bend, steps 32 narrow in the direction of the center of the bend. When platform 12 is moved along rail 10, the platform needs to be prevented from hitting the walls of the stairwell, or the steps. Whether there is a risk of this happening depends on inter alia the width of the stairwell and the height of rail 10 above the steps.

[0035] Even when rail 10 is mounted so high above the steps that there is no risk of collision with steps 32 on the straight parts of the stairway, there 25 may, for instance, be a local risk of collision in the bend due to the narrowing of steps 32. In the prior art, in case of a stairway with a bend, it was therefore necessary to mount rail 10, at least at the location of the bend, higher above steps 32 than necessary in the straight parts. This prevents the risk of collision with steps 32. However, this reduces the headroom above the platform. This may in turn cause problems in stairwells with limited space.

[0036] According to the invention, the risk of collisions with steps 32 in the bend is avoided by rotating the platform locally in the bend relative to 5 rail 10 about vertical shaft 18, in order to thus avoid steps 32. This makes it possible to mount rail 10 less high relative to the steps 32, so that more headroom is left.

[0037] Also, according to the invention, this problem of reduced headroom is addressed by tilting platform 12 about horizontal axis 39 whenever expedient. Thus, for example, it is possible to provide the rail 10 with a constant distance from the steps over the whole length of the stairway, as potential collisions with objects 17 above the platform 12 can be addressed by tilting the platform and effecting movement of the platform in a tilted orientation when passing such objects.

[0038] Although preferably use is made of programmed paths, it is also possible to have microcontroller 20 choose the paths dynamically. For this purpose, the stairlift can be equipped with collision sensors, on the basis of which microcontroller 20 can adjust the angle. If it has been checked in advance that there is a simple path, microcontroller 20 can thus choose that path dynamically. In addition, incidental obstacles can be avoided, or cause interruption of the movement.

[0039] Preferably, the vertical shaft coincides with the centre of a circle which is essentially formed by an outside of a back and armrests of a chair forming the platform. Thus, the back is no obstruction to rotations.

[0040] Although the invention has been described for a particular construction of the swivel mechanism, it will be clear that the invention can also be applied to other mechanisms. For instance, a displaceable vertical rotary shaft can be used about which the platform rotates. Here, for instance a fixed coupling is possible between angle of rotation and shaft displacement. This in itself does not change the principles of the invention.

[0041] Although the rotation of platform 12 about the vertical and horizontal shafts 19 is preferably controlled electronically, it will be clear that mechanical solutions are also possible, with which, depending on the position of platform 12 along rail 10, the required rotations can be generated. For this, similar techniques can be used as for leveling.

[0042] Although preferably use is made of a uniform speed of movement of platform 12 along rail 10, with rotations coupled thereto, use can also be made of non-uniform speeds without deviating from the invention. For instance, microcontroller 20 can be programmed to temporarily decelerate the movement along rail 10 if a rotation about vertical a shaft is necessary. This may, for instance, reduce the maximum acceleration.

[0043] Preferably, microcontroller 20 is also programmed with safety measures in order to move platform 12 back along rail 10, or, if possible, move it at an angle free from collision, upon detection of blocking of the rotation about vertical shaft 18. For instance, in a sufficiently wide stairwell, upon blocking, it can be decided not to rotate platform 12 so as to be perpendicular to rail 10 in the straight parts (so that the transported person is not sitting with the back directly to the wall).

Claims

1. Stairlift comprising a rail (10) for mounting along a stairway, a platform (12) which is movably mounted on the rail (10) and a drive mechanism (14, 15, 16, 26, 27, 28) for moving the platform (12) along the rail (10), wherein the platform (12) is mounted so as to be rotateable about a vertical axis (18), characterized in that the platform (12) is further mounted so as to be tiltable about a horizontal axis (19) such that it can be tilted out of a horizontal orientation into a tilted orientation.

2. Stairlift according to claim 1, wherein the tilted orientation is such that a side of the platform (12) facing in the upward direction of the stairway is lower than a side of the platform (12) facing in the downward direction of the stairway.

3. Stairlift according to claim 1 or 2, wherein the platform (12) is adapted such that the tilted orientation is within a range of 0° - ± 20° in particular between 0° - ±15° with respect to the horizontal orientation.

4. Stairlift according to any one of the preceding claims, wherein the platform (12) is adapted to be moved along rail (10) while or after being tilted into the tilted orientation.

5. Stairlift according to any one of the preceding claims, wherein the platform (12) is adapted to be moved along rail (10) while or after being rotated.

6. Stairlift according to any one of the preceding claims, comprising at least one collision sensor (24b) for sensing obstacles in the path or vicinity of platform (12), and a control device (20) for controlling movement of platform (12) in reaction to signals received from the at least one sensor, wherein the control device (20) is adapted to tilt platform (12) about horizontal axis (19) and/or rotate platform(12) about vertical axis (18) in the vicinity of obstacles.

7. Stairlift according to any one of the preceding claims wherein the drive mechanism for moving the platform (12) along the rail (10) comprises a first motor (14), a second motor (16) being provided which is adapted to maintain platform (12) in a horizontal orientation, a third motor (15) being provided which is adapted to rotate platform (12) about a vertical access 18, and a fourth motor (21) being provided adapted to tilt platform (12) out of its horizontal orientation into a tilted orientation.

8. Stairlift according to claim 7, wherein the fourth motor (21) is positioned above the third motor (15).

9. Method for driving a platform of a stairlift along a rail mounted on a stairway, comprising the steps of automatically rotating the platform (12) about a vertical axis (18) or shaft before and/or during movement of the platform, and automatically tilting the platform about a horizontal axis or shaft (19) before or during movement of platform (12), such that the platform is tilted out of a horizontal orientation into a tilted orientation, and moved along rail (19) in a tilted orientation.

Drawing