LIFT ASSEMBLY AND METHOD FOR MOVING A LIFT

Abstract: A lift assembly comprising a rail system including a supporting section (6) and a lift (7), for example a chair lift for a disabled person, comprisisng a rotatable guide unit (8) which is movable along said supporting section (6), wherein the lift (7) is capable of upward and downward movement at various angles of inclination, said lift (7) comprising a carrier and means for maintaining the carrier substantially in a predetermined position during said movement, wherein the means for maintaining the carrier substantially in a horizontal position during its movement comprise a guide surface (21) present in the rail system, along which detection means (22, 23) mounted on the lift (7) can move.

Description: LIFT ASSEMBLY AND METHOD FOR MOVING A LIFT The invention relates to a lift assembly comprising a rail system including a supporting section and a lift, for example a chair lift for a disabled person, which is movable along said supporting section, wherein the lift is capable of upward and downward movement at various angles of inclination, the horizontal direction included, said lift comprising a carrier and means for maintaining the carrier substantially in a predetermined position during said movement . This kind of lifts can be used for carrying a disabled person, who is unable to use the stairs, up or down along the staircase. The rail system is thereby mounted along the staircase in such a manner that a lift disposed above the staircase can move along said rail system. The rail along which the lift moves may be fixed to a wall beside the staircase, for example, but it may also be fixed to supports which are secured to the treads on the side of the staircase. The carrier may be in the form of a chair on which a person can be seated, but it may also consist of a platform onto which an invalid chair can be moved. Also other lift constructions are possible. In the case of a straight staircase, the rail system may consist of a straight assembly of sections, which is mounted at the same angle as the staircase . The connection between the lift and said rail system is effected in that the lift engages the rail system by means of one or more guide units attached to the lift, wherein the lift occupies a substantially straight position, that is, extending at a particular angle with respect to the rail system, at all times. The rail system may furthermore be provided with a rack, which can mesh with a gear attached to the lift, so that when the gear is driven by means of an electric motor present in the lift, the lift is moved along the rail system. Usually a staircase comprises not only a straight portion, but a staircase may extend at different angles of inclination at different locations, it may comprise a horizontal portion (that is, a portion wherein the angle of inclination is 0°) and it may comprise bends. In all the above cases the rail system extending along the staircase must be so constructed that the lift will maintain a predetermined position at all times during its movement along the rail system, the rail system may be fitted with two supporting guides for that purpose, wherein the position of the lift with respect to the rail system is determined by the spacing between the supporting guides. Consequently, said spacing must vary such that, depending on the angle of inclination of the rail system, a predetermined lift position will be maintained at all times. The two guides may be positioned more closely together when the inclination of the staircase, and thus of the rail system, is steeper. One drawback of a system of this kind is the fact that the use of two supporting guides involves additional installation costs and the use of additional materials, whilst also additional space is required and the optical effect is not very aesthetic. EP 0 5S0 433 discloses a lift assembly wherein only one supporting guide is used. In order to maintain a fixed lift position, a cam disc which is mounted in the lift is used, which cam disc rotates synchronously with the lift movement. The cam disc contains information on the angles of inclination, and a cam follower moves the lift to the desired position. One drawback of such a system is that when a lift assembly is to be mounted along a particular staircase, the staircase must be precisely measured, after which the shape of the cam disc must be calculated on the basis of said measurement. In practice the system appears to be very sensitive to deviations in the cam disc, which is relatively small in comparison with the total length of the staircase, as a result of which it is difficult to maintain a straight position of the lift. Generally, one drawback of prior art lift assemblies is the fact that they must be made precisely to size on the basis of complicated calculations, whereby the staircase must first be measured without any measuring errors, and another drawback is that when a rail system is to be removed from a house, it can hardly be reused, if at all, for another lift assembly to be produced. The object of the invention is to provide a lift assembly comprising one supporting guide, which is maintained in a predetermined position in an effective manner. According to another object of the invention, the rail system is designed such that it can be reused, at least to a large part, and means for maintaining a fixed position of the carrier are provided in a simple and reliable manner upon installation. Especially because sometimes a lift assembly is present in a house for only a short period of time, after which it must be removed again, it is very advantageous if a considerable part of such a lift assembly can be reused and be installed in a simple manner. According to one aspect of the invention, the means for maintaining the carrier substantially in a horizontal position during its movement comprise a guide surface present in the rail system, along which detection means mounted on the lift can move. The advantage of this is that the information on the angle of inclination of the rail system is inherently present along the entire length of the staircase, which is conducive towards a reliable operation and which eliminates the need to preset the system at the factory. Preferably, said detection means comprises at least one roller, which can roll on said guide surface, thus achieving frictionless, precise guidance. Furthermore, the supporting section preferably has a constant cross-sectional dimension substantially along its entire length, for example consisting of a round tube, and the rail system comprises a supporting surface substantially along its entire length, and the lift includes stabilizing means abutting against said supporting surface, wherein said stabilizing means comprises a roller which can roll on said supporting surface, so that the lift is prevented from rotating round the supporting section, whilst nevertheless only one supporting section is used. The supporting surface is preferably made up of a lateral surface of a rack mounted on the supporting section, which can mesh with a driven gear of the lift. Thus, the aspects mentioned in the preceding paragraph are combined with the lift drive in a compact and material-saving manner. The rack is preferably mounted on the underside of the supporting section. In one preferred embodiment of the lift assembly, a bar mounted along the supporting section, in spaced relation thereto, is provided with the guide surface along which the detection means can move, wherein said bar may be disposed obliquely above and/or beside and/or obliquely below said supporting section. As a result, said supporting section and said bar can overlap at least partially, seen in side view, which is conducive towards a compact an optically attractive construction of the lift assembly. Preferably, the bar is a round tube having a diameter smaller than that of the supporting section, preferably less than two thirds thereof, more preferably less than half said diameter. Preferably, the position of the bar relative to the supporting section, seen in a transverse plane, varies in dependence on the angle of inclination, and the location where the detection means abuts against the guide surface is spaced from the vertical plane through the axis of rotation of the guide unit by some distance. Said spacing is preferably larger than 50 mm, more preferably larger than 75 mm. This makes it possible to have the detection means function also as a mechanical support for maintaining the carrier in a fixed position, which is a simple, reliable and cost-saving aspect. This will be explained in more detail yet with reference to the figures. Preferably, the detection means is positioned obliquely above said axis of rotation of the guide unit . In another preferred embodiment of the lift assembly, the guide surface is made up of a portion of the surface of the supporting section. This is a cost-reducing measure, since it is not necessary to provide an external guide surface . Preferably, the detection means detects a change in the angle of inclination of the supporting section, and the position of the carrier is adjusted in response thereto. To this end, the detection means preferably moves along the guide surface in spaced relation to the guide unit, both before and behind the guide unit. The part of the detection means which moves along the guide surface is preferably connected to the guide unit by means of a pivoted arm, and the guide unit may for example comprise a switch which is connected to said pivoted arm. Preferably, the detection means is furthermore connected to an adjusting motor, which is capable of maintaining the carrier in a fixed position. The above aspects make it possible to maintain the carrier in a fixed position in an efficient manner. More preferably, the speed at which the carrier is controlled and/or the speed of the lift depend (s) on the position of the pivoted arm in this embodiment. This ensures a comfortable, smooth and precise movement of the lift. Preferably, correction means are furthermore present for carrying out an error correction for the carrier position, whereby for example said correction means measure the angle between the carrier and the lift on a portion of the supporting guide that has an angle of inclination which is known. Said correction means are capable of correcting the errors in the lift position that may occur after some time. Thus, the lift can be moved to a predetermined position with respect to the supporting guide each time when it reaches its end position, at the top or at the bottom of the rail system, whereby a possible error in the carrier position is corrected. The invention furthermore relates to a method for moving a lift along a rail system including a supporting section as defined in the claims. The above aspects, which are defined in the claims, can be used separately as well as in combination with each other. Further aspects will be disclosed by means of exemplary embodiments . In order to explain the invention more fully, a number of exemplary embodiments of a lift assembly will now be described with reference to the schematic drawing. Figure 1 is a view of a lift assembly; Figure 2 is a partial cross-sectional view of a rail system and a lift; Figure 3 is a view of a first exemplary embodiment of a lift assembly fitted with detection means; Figure 4 is a partial cross-sectional view of the first embodiment of a rail system with a lift fitted with detection means; and Figure 5 shows a second embodiment of a lift assembly fitted with detection means in various positions thereof. The figures are merely schematic representations of the exemplary embodiments, wherein parts corresponding to each other are indicated by the same numerals. Some parts of the lift assembly have been left out for the sake of clarity. Figure 1 shows a lift assembly mounted on a staircase. A plurality of supporting members 2 are mounted on a staircase 1 by means of bases 3 which can be fixed to the treads of a staircase, for example by means of screws . Said bases 3 may include an additional tube member 29, so as to enable adjustment of the height of the supporting member 2. This will be explained with reference to Figure 4. Each supporting member 2 has a point of attachment 4, to which a supporting section 6 can be attached by means of a fixing element 5. Said supporting section 6 is assembled from a plurality of straight tube sections and a plurality of bent tube sections of circular cross-section. Said tube sections are interconnected by coupling members, which can be slid into the ends of two joining tube sections. The interconnection of the tube sections may be strong enough by itself already, because the coupling members are provided with a clamped fit, but it is also possible to secure the ends of the tube sections to the coupling members by means of screws. Supporting section 6 is attached to the fixing element 5, which can rotate about a horizontal axis of rotation through point of attachment 4, in such a manner that the central axis of said section 6 intersects the horizontal axis of rotation through point of attachment 4. Figure 1 also shows a lift in several positions thereof, which lift may comprise a chair for moving a handicapped person along the staircase in seated position. The lift comprises a frame 7 (represented only schematically) , to which a guide unit 8 is attached, which is capable of rotation about a horizontal axis 9 with respect to frame 7. A carrier, a chair in this embodiment, which is rigidly connected to frame 7, is maintained in a fixed position thereof through the use of detection means (not shown) which moves along a guide surface, two embodiments of which will be discussed in more detail hereafter. Guide unit 8 comprises guide rollers 10, 11, which can roll on supporting section 6 with a concave tread. Guide unit 8 furthermore comprises a third guide roller 12, which can likewise roll on section 6. Guide unit 8 is rotatable with respect to frame 7 about a substantially horizontal axis 9, which intersects the central axis of supporting section 6. The driving gear of the lift consists of a rack 13, which is mounted under supporting section 6 and which has downwardly extending teeth. Said teeth can mesh with a gear 14, which is disposed beside guide roller 12 and which is driven via a shaft on which said guide roller 12 is mounted. The above-described driving gear is also shown in Figure 2 and will be explained in more detail with reference to that figure. Figure 2 shows a detail, wherein the rail system is shown partially in sectional view, as is part of the lift. The figures shows a supporting member 2 of the rail system, to which fixing element 5 is attached. The figure illustrates the manner in which supporting section 6 is fastened to supporting member 2 by means of bolts 15, in that fixing element 5 is provided with a hole, through which bolt 15 can extend, and supporting section 6 is provided with a threaded hole, into which bolt 15 can be screwed. Fixing element 5 can be fixed in various angular positions with respect to axis of rotation 16 thereby. Axis of rotation 16 coincides with point of attachment 4 as shown in Figure 1. By attaching supporting section 6 to the fixing elements 5 in this manner, the tubes that make up the supporting section 6 can be reused without the presence of the threaded holes being objectionable thereby. Possibly, said holes can be covered by screwing a screw into said holes. Guide rollers 10, 11 and a guide roller 12 can roll on supporting section 6. Guide roller 12 is mounted on shaft 17 of electric motor 18, which drives the lift. To that end, gear 14 engages in a rack 13 which is mounted on the underside of supporting section 6. In this embodiment, gear 14 is mounted directly on the shaft of electric motor 18, but it is also possible for gear 14 to be driven by an electric motor via a reduction gear unit. Guide unit 8 comprises a roller 37, which can roll on the side of rack 13, thus preventing the lift from rotating round supporting section 6. Referring to Figures 3 and 4, a first exemplary embodiment of the invention will now be described. Each supporting member is provided with an additional point of attachment 19. A bar 21 is attached to said point of attachment, on the side of supporting member 2 disposed opposite fixing element 5, by means of a fixing element 20. This makes it possible for bar 21 to intersect the supporting section, seen in side view. In this first embodiment, bar 21 is a tube of circular cross-section, whose outer surface forms a guide surface, on which rollers 22 and 23 can roll. Bar 21 is attached to supporting member 2 in a similar manner as supporting section 6. A bolt 24 is thereby screwed into bar 21, as a result of which bar 21 is attached to fixing element 20 and fixing element is attached to supporting member 2. Bar 21 is fixed to supporting member 2 in such a manner that the central axis of bar 21 intersects the central axis of point of attachment 19. Fixing element 20 can rotate about a horizontal axis of rotation through point of attachment 19 for that purpose, to which fixing element 20 bar 21 is attached. The relative positions of supporting section 6 and bar 21 other must be so geared to the construction of the lift to be moved along the rail system that said lift will maintain a straight position at all times while moving along its track. It will be apparent that there is a relation between the location of points of attachment 4, 19 and the spacing between supporting section 6 and bar 21. In one preferred embodiment, a supporting member 2 for supporting section 6 and bar 21 is provided with a fixing element 5, 20 for each of said points of attachment 4, 19 disposed at fixed locations, by means of which said points of attachment can be connected to supporting member 2 at the desired angle, and that in such a manner that a predetermined spacing between supporting section 6 and bar 21 will be adjusted at any desired angle. The axes of rotation of fixing elements 5, 20 of a supporting member 2 are preferably lie in different, spaced-apart vertical planes thereby. Frame 7 is fitted with detection means in the form of a guide unit 25 comprising rollers 22 and 23, which both have a concave tread and which can roll on bar 21. Guide unit 25 is rotatable with respect to frame 7 about a substantially horizontal shaft 27, which intersects the central axis of bar 21. As is apparent from Figure 3, the axes of rotation of guide units 8 and 25 are so positioned on frame 7 that said axes of rotation will coincide with the points of attachment 4 and 19 of a supporting member when the lift is positioned at a particular location near the supporting member. As a result, the lift will occupy the same fixed position at all times. Figure 4 shows the situation wherein the lift is so positioned on the rail system that the axis of rotation 16 of fixing element 5 coincides with the axis of rotation 9 of the lower guide unit 8, and wherein axis of rotation 26 of the upper fixing element 20 coincides with axis of rotation 27 of the upper guide unit 25. Figure 4 furthermore shows the manner in which the height of support 2 can be adjusted. Tube end 28 of supporting member 2 has been slid into a tube member 29 of base 3 for that purpose. The height of supporting member 2 is determined by the length of tube member 29, which can easily be made to length. Figure 5 shows another embodiment, wherein the lift is shown in various positions thereof. Guide unit 8 is thereby provided with a lateral point of attachment 30 on the upper side, to which an adjusting unit 31 is pivotally connected. Said adjusting unit may comprise an electric motor with a screwed spindle or rack-and-pinion reduction gearing, which is directly connected to point of attachment 30. The upper end of adjusting unit 31 is connected to frame 7, on which a chair can be mounted. The adjusting unit 31 is controlled by two switches (not shown) , which are connected to and operated by detection means in the form of two spring-loaded, forwardly and rearwardly extending arms 32, 33, which are pivotally connected to guide rollers 10 and 11, on which wheels 34, 35 are mounted. Said wheels roll on a guide surface 36, which is formed by the upper side of supporting section 6. When the angle of inclination of supporting section 6 changes, one switch will first be moved to its lower or upper position. The moment the angle of inclination of guide unit 8 changes, also the second switch will be moved to the lower or the upper position, and the motor of adjusting unit 31 will be activated to adjust the angle between guide unit 8 and frame 7. Adjusting unit 31 will be deactivated as soon as guide unit 8 has reached the new angle of inclination and one of the two switches has moved to the central position. The degree to which an adjustment to the various angles of inclination is to be made can be set by storing information on successive angles of inclination of the supporting section 6 on an information carrier, which is connected to the control unit of adjusting unit 31. Also an embodiment wherein the switches are capable of accurately measuring the changes in the angle of inclination is possible. The adjusting unit 31 can only function when the lift motor 18 is activated. The direction of rotation of the motor of adjusting unit 31 depends on the direction of rotation of the lift motor 18 (lift moving up and down) , and it is controlled by the position of the switches (up or down) . If the bending radius of the vertical bends in supporting section 6 is the same, there will be a difference in the distance travelled in an inside bend and an outside bend (seen in the vertical plane) . This can be overcome by having the speed of the movement of adjusting unit 31 depend on the position of the two switches. This dependence can also be used for decelerating and accelerating near vertical bends, whereby the speed depends on a change in the position of one of the two switches . The lift may be fitted with two stop switches, which limit the travel of guide unit 8 on supporting section 6. The angles of inclination in certain parts of supporting section 6 are known, so that it is possible to incorporate a facility in the control system by which the position of frame 7 is determined and corrected, if necessary, when the lift is at a standstill in such a part, for example at the stop switches. This may for example be done by measuring the angle between frame 7 and guide unit 8 at the pivoting point. According to a possible alternative, an electronic level is incorporated in frame 7, which checks its position continuously and corrects it, if necessary, and which stops the lift when the deviation is found to be too large . The use of the lift assembly as described above enables relatively quick and easy installation of the lift assembly, even without measuring the staircase precisely in advance. All elements can be reduced with hand tools and made to size by means of said tools. The installation of a lift system has thus become relatively easy. Also the dismounting of the lift assembly can take place in a simple manner, such that the parts can be reused after being disassembled. It is possible thereby to sort the used parts and store them until certain parts can be reused. It is also possible, however, starting from an existing lift assembly which is to be removed, to form a new lift assembly, and that to size, for another staircase. By measuring both the old staircase and the new one it is then possible to determine by means of a relatively simple calculation which parts of the old lift assembly can remain unchanged, which parts are to be reduced and/or which parts are to be supplemented with parts to be added. The above-described embodiment is to be considered as such, it can be varied in many ways within the scope of the invention.

Claims: CLAIMS 1. A lift assembly comprising a rail system including a supporting section (6) and a lift (7) , for example a chair lift for a disabled person, comprising a rotatable guide unit (8) which is movable along said supporting section (6) , wherein the lift (7) is capable of upward and downward movement at various angles of inclination, said lift (7) comprising a carrier and means for maintaining the carrier substantially in a predetermined position during said movement, characterized in that the means for maintaining the carrier substantially in a horizontal position during its movement comprise a guide surface (21) present in the rail system, along which detection means (22, 23) mounted on the lift (7) can move. 2. A lift assembly according to claim 1, characterized in that said detection means comprises at least one roller (22, 23), which can roll on said guide surface (21) . 3. A lift assembly according to claim 1 or 2 , characterized in that said supporting section (6) has a constant cross-sectional dimension substantially along its entire length. 4. A lift assembly according to any one of the preceding claims, characterized in that said supporting section (6) comprises a substantially round tube . 5. A lift assembly according to any one of the preceding claims, characterized in that the rail system comprises a supporting surface (13) substantially along its entire length, and in that the lift (7) includes stabilizing means (37) abutting against said supporting surface, wherein said stabilizing means comprises a roller which can roll on said supporting surface, so that the lift (7) is prevented from rotating round the supporting section (6) , wherein said stabilizing means preferably comprises a roller (37) which can roll on said supporting surface (13) . 6. A lift assembly according to claim 5, characterized in that said supporting surface is made up of a lateral surface of a rack (13) mounted on the supporting section (6) . 7. A lift assembly according to any one of the preceding claims, characterized in that a rack (13) is mounted on the supporting section (6) , which rack can mesh with a driven gear (14) of the lift (7) . 8. A lift assembly according to any one of the preceding claims, characterized in that a bar (21) mounted along the supporting section (6) , in spaced relation thereto, is provided with the guide surface along which the detection means (22, 23) can move . 9. A lift assembly according to claim 8, characterized in that said bar (21) is disposed obliquely above and/or beside and/or obliquely below said supporting section (6) . 10. A lift assembly according to claim 8 or 9, characterized in that said supporting section (6) and said bar (21) overlap at least partially, seen in side view. 11. A lift assembly according to any one of the claims 8 - 10, characterized in that the position of the bar (21) relative to the supporting section (6) , seen in a transverse plane, varies in dependence on the angle of inclination. 12. A lift assembly according to any one of the claims 8 - 11, characterized in that the location where the detection means abuts against the guide surface is spaced from the vertical plane through the axis of rotation (9) of the guide unit (8) by some distance. 13. A lift assembly according to any one of the preceding claims 1 - 7, characterized in that the guide surface is made up of a portion of the surface of the supporting section (6) . 14. A lift assembly according to claim 13, characterized in that the detection means detects a change in the angle of inclination of the supporting section (6) , and the position of the carrier is adjusted in response thereto. 15. A lift assembly according to claim 13 or 14, characterized in that the detection means preferably moves along the guide surface in spaced relation to the guide unit (8) . 16. A lift assembly according to any one of the preceding claims 13 - 15, characterized in that the detection means preferably moves along the guide surface in spaced relation to the guide unit both before and behind the guide unit (8) . 17. A lift assembly according to any one of the preceding claims 13 - 16, characterized in that the part of the detection means which moves along the guide surface is connected to the guide unit (8) by means of a pivoted arm. 18. A lift assembly according to claim 17, characterized in that said guide unit (8) comprises a switch, which is capable of switching in dependence on the position of said pivoted arm. 19. A lift assembly according to any one of the preceding claims 13 - 18, characterized in that said detection means is connected to an adjusting motor, which is capable of maintaining the carrier in a fixed position. 20. A lift assembly according to any one of the preceding claims 17 - 19, characterized in that the speed at which the carrier is controlled and/or the speed of the lift (7) depend (s) on the position of the pivoted arm. 21. A lift assembly according to claim 21, characterized in that correction means are present for carrying out an error correction for the carrier position. 22. A lift assembly according to claim 21, characterized in that said correction means measure the angle between the carrier and the lift (7) on a portion of the supporting guide that has an angle of inclination which is known. 23. A method for moving a lift (7), for example a chair lift for a disabled person, along a rail system comprising a supporting section (6) , wherein the lift (7) , which comprises a rotatable guide unit (8) , is moved along said supporting section (6) , wherein said lift (7) moves upward and downward at various angles of inclination, which lift (7) comprises a carrier and means for maintaining the carrier substantially in a predetermined position during said movement , characterized in that detection means mounted on the lift (7) can move along a guide surface present in the rail system.

Inventors: OOMS ALEX, OOMS OTTO, OOMS, ALEX, OOMS, OTTO
Applicants: OOMS OTTO BV, OTTO OOMS B.V.
Application year: 1999
Main classification: B66B9
IPC codes: B66B9