EP3326955A1

EP3326955A1 - An apparatus for transporting a load from a first to a second level, in particular a stairlift

Info

Publication number: EP3326955A1
Application number: EP17202074.5A
Authority: EP
Inventors: Jacco Frederik DE HAAN; Martinus Cornelis Van Scheppingen; Jan Otto OOMS
Original assignee: Otto Ooms BV
Current assignee: Otto Ooms BV
Priority date: 2016-11-23
Filing date: 2017-11-16
Publication date: 2018-05-30
Anticipated expiration: 2037-11-16
Also published as: EP3326955B1; NL2017842B1

Abstract

An apparatus (4) for transporting a load from a first to a second level comprising an emergency rotation blocking arrangement for preventing rotation between the load carrier (10) and the frame (9) of said apparatus, said rotation blocking arrangement comprising:
a first braking member (21) having a primary braking surface which is strip shaped and extends along at least a section of a circle around said axis,
a second braking member (22) having at least one secondary braking surface which extends at a distance from said primary braking surface at an angle in such a manner that the distance between the two surfaces varies, thereby forming a substantially wedge shaped gap between the primary and secondary surfaces having a wider part and a narrower part, the wedge shaped gap widening in a tangential direction around said axis,
wherein in a normal operation mode a third braking member (23) is held in a fixed position relative to said second braking member (22) by a retaining member (24) such that it extends in the wider part of said wedge shaped gap where it cannot engage both the primary and secondary braking surfaces at the same time, and
wherein in a braking operation mode said retaining member (24) is moved relative to said second braking member (22) such that said third braking member (23) is allowed to move to the narrower part of said wedge shaped gap, thereby engaging both the primary and secondary braking surfaces and blocking rotation of the second braking member (22) in said tangential direction relative to the first braking member (21).

Description

The invention relates to an apparatus for transporting a load from a first to a second level, in particular a stairlift, comprising: a frame which is displaceable along a rail and which is provided with support, guide and drive means arranged to engage the rail, a load carrier, in particular comprising a seat for a person, which is rotationally mounted on said frame to be rotated around a horizontal axis, and means for maintaining the load carrier in a predetermined rotational position relative to the direction of gravity, which position-maintaining means comprise at least one adjusting motor arranged to rotate the load carrier relative to the frame around said horizontal axis.
Such apparatuses are described in WO 2006/001694 , WO 2012/120286 and WO 2012/052725 , and each comprise an emergency blocking mechanism for preventing the carrier from uncontrolled rotational movement should the means for maintaining the carrier in the predetermined rotational position fail, in particular to prevent injuries to person sitting on the carrier.
The invention aims at an alternative, more reliable, more simple emergency blocking solution.
To that end said apparatus further comprises an emergency rotation blocking arrangement for preventing said rotation between the load carrier and said frame, said rotation blocking arrangement comprising: a first braking member rigidly connected to one of said frame and said load carrier, a second braking member rigidly connected to the other one of said frame and said load carrier, at least one third braking member arranged between said first braking member and said second braking member, wherein said first braking member has a primary braking surface which is strip shaped and extends along at least a section of a circle around said axis, wherein said second braking member has at least one secondary braking surface which extends at a distance from said primary braking surface at an angle in such a manner that the distance between the two surfaces varies, thereby forming a substantially wedge shaped gap between the primary and secondary surfaces having a wider part and a narrower part, the wedge shaped gap widening in a tangential direction around said axis, wherein in a normal operation mode said third braking member is held in a fixed position relative to said second braking member by a retaining member such that it extends in the wider part of said wedge shaped gap where it cannot engage both the primary and secondary braking surfaces at the same time, and wherein in a braking operation mode said retaining member is moved relative to said second braking member such that said third braking member is allowed to move to the narrower part of said wedge shaped gap, thereby engaging both the primary and secondary braking surfaces and blocking rotation of the second braking member in said tangential direction relative to the first braking member. In the preferred embodiment said first braking member is rigidly connected to said frame and said second braking member is rigidly connected to said load carrier. In normal operation the carrier and the frame can be rotated relative to each other. If an unexpected situation occurs (such as if a sensor on the carrier senses that the rotational angle exceeds an acceptable maximum) or for instance any time that the apparatus is at a standstill or switched off, the retaining member will be moved, whereby the third braking member moves into the narrow part of the wedge where it contacts both surfaces. If in such a case there would be a rotation between the carrier and the frame, the frictional forces of both surfaces will cause the third braking member to move deeper into narrower part of the wedge, possibly even being deformed thereby, and in any case completely blocking the relative rotation between the carrier and the frame, and at any incremental angle.
Preferably said second braking member comprises at least two secondary braking surfaces, being at least one first secondary braking surface and at least one second secondary braking surface, said at least one first secondary braking surface forming a first substantially wedge shaped gap widening in a first tangential direction around said axis, and said at least one second secondary braking surface forming a second substantially wedge shaped gap widening in a second tangential direction around said axis, said second tangential direction being the opposite of said first tangential direction, and said at least one third braking member being allowed by said retaining member in said braking operation mode to move to a narrower part of one of said first and second substantially wedge shaped gaps, thereby allowing said at least one third braking member to block rotation of the second braking member in either tangential direction relative to the first braking member. Thereby the emergency blocking arrangement works in both rotational directions.
Said at least first secondary surface and said at least second secondary braking surface preferably form two separate substantially wedge shaped gaps, and said at least one third braking member are at least two separate third braking members, each extending in a respective substantially wedge shaped gap. Said blocking arrangement preferably comprises a multitude of first and secondary braking surfaces forming substantially wedge shaped gaps and a multitude of third braking members, each extending in a respective substantially wedge shaped gap.
Preferably said primary braking surface is at least a section of a cylindrical surface. Said primary braking surface may also be at least a circular section of a conical or a flat surface. Preferably said at least one third braking member has the form of a cylinder, and the axis of said cylinder extends parallel to both the primary and secondary braking surfaces. Said third braking member may also be speherical.
The wider part(s) of said wedge shaped gap(s) preferably extend(s) substantially vertically above the narrower part(s) of said wedge shaped gap(s) and said third braking member(s) rest(s) on (a) carrying edge(s) of said retaining member in the normal operation mode. Preferably said retaining member is movable between an upper position in said normal operation mode and a lower position in said braking operation mode. Preferably said retaining member is held in said upper position in normal operation by the force of an electrically powered electromagnet, such that it moves to said lower position in braking operation if electrical power to said electromagnet is absent. Said retaining member is furthermore preferably connected to a resilient biasing member which is arranged to move said retaining member from said fixed position in normal operation mode to said braking operation mode.
The invention will now be elucidated by means of a preferred embodiment as shown in the figures, wherein:

Figure 1 shows a perspective view of an exemplary embodiment of a stairlift;
Figure 2 shows an exploded perspective view of a displaceable frame and a carrier for a stairlift as shown in figure 1, with an emergency rotation blocking arrangement mounted there between;
Figure 3 shows an exploded perspective view of the emergency rotation blocking arrangement of figure 2; and
Figures 4A and 4B show a front view of the emergency rotation blocking arrangement of figure 3 in normal operation mode and in braking operation mode respectively.

Figure 1 shows an system 1 for transporting a load from a first to a second level, in the shown embodiment a stairlift system, which comprises a rail 3 which is placed along a staircase 2 and which encloses an angle α with the horizontal H, and an apparatus 4 movable along rail 3 for transporting the load between the different levels. Rail 3, which in the shown embodiment has a round cross-section, is supported by a number of posts 5 which are arranged distributed along staircase 2 and which are fixed to a protruding part extending along rail 3. Rail 3 is further provided with a propelling part in the form of a gear rack 8. Stairlift 4 comprises a frame 9 which is displaceable along rail 3 and on which a load carrier 10 is mounted, here in the form of a chair with a seat 11, back rest 12, armrests 13 and a footrest 14. Chair 10 is connected to frame 9 by a rotatable shaft 15 and fixation means 16, 17 (shown in figure 2) for rotating around a horizontal axis, and arranged in frame 9 and carrier 10 is a level maintaining mechanism consisting of, among other parts, of an adjusting motor connected to said shaft 15 so that the position of chair 10 can be kept constant at all times irrespective of the inclination of rail 3. For further details of an embodiment of a system as shown here, reference is made to European patent application publication EP 2 216 284 A1 , which is incorporated herein by reference. This description will hereafter focus on the new emergency rotation blocking arrangement between the frame 9 and the load carrier 10.
According to figures 2 and 3, an emergency rotation blocking arrangement is mounted between a frame 9 and a load carrier 10. The rotation blocking arrangement comprises a first braking member 21, a second braking member 22, a plurality of third braking members 23, and a retaining member 24 for holding the third braking members 23 in position.
The first braking member 21 comprises a cylindrical part 212 extending around the hollow shaft 15, and a mounting flange 213. The first braking member 21 is rigidly connected to the frame 9 by bolts 211 extending through holes 214 in said flange 213.
The second braking member 22 comprises a substantially cylindrical body extending around the cylindrical part 212 of the first braking member 21, such that it can rotate relative thereto. The second braking member 22 is rigidly connected to the load carrier 10 by bolts 221 extending through holes 222 in said body and washers 223.
The retaining member 24 comprises 2 substantially U-shaped flat plates 241, 242, each extending on one side of the second braking member 22, such that they form a sandwich. The plates 241, 242 are fixed to each other by bolts 243 and nuts 244, while bushings 245 extend between the plates 241, 242 and around the bolts 243 as spacers. The bushings 245 extend through vertical slots 224 in the second braking member 22, whereby the retaining member 24 is movable up-and-down between two extreme positions. A biased spring 246 is provided, of which the upper end pushes against a fixed stop surface on the load carrier 10, and the lower end pushes against a stop surface of a protrusion 247 of the retaining member 24, thereby pushing the retaining member towards the lower position. Furthermore an electromagnet 248 is provided, which is mounted on the load carrier above the metal protrusion 247 of the retaining member 24. When, in the normal operation mode, the electromagnet 248 is powered, it pulls the metal protrusion 247 in the upper direction against the force of spring 246, thereby moving the retaining member 24 to the upper position. If, in the braking operation mode, the electromagnet is not powered, the spring 246 pushes the retaining member 24 back to the lower position.
The second braking member 22 comprises recesses 225 in its inner circumferential wall around the cylindrical part 212 of the first braking member 21, such that the surface of said recesses 225 face the outer surface of the cylindrical part 212. As shown in figures 4A and 4B, said the surface of the recesses is shaped such that the surface of each recess 225 and said surface of the cylindrical part 212 form substantially wedge shaped gaps 231, having a wider part in its upper region and a narrower part in its lower region.
The third braking members 23 have a cylindrical main body 232 and a shaft 233 extending from both ends. The plates 241, 242 of the retaining member 24 have substantially vertical slots 249 in which the shafts 233 of the third braking members 23 extend, with washers 234 being placed between the main body 232 and the slots 249. The braking members 23 can thereby freely rotate around the shafts 233 and move freely up-and-down the slots 249.
In the normal operation mode, when the retaining member 24 is forced to be in the upper position by the electromagnet 248, the bottom edge of the slots 249 of retaining member 24 carry the shafts 233 of the third braking members 23 such that their main bodies 232 are forced to extend in the wider parts of the wedge shaped gaps 231, as shown in figure 4A. In that position the first braking member 21 and the second braking member 22, and thereby the frame 9 and the load carrier 10, can freely rotate relative to each other.
In the braking operation mode, when the retaining member 24 is forced to be in the lower position by the spring 246, the slots 249 overlap the lengths of the gaps 231, whereby the shafts 233 of the third braking members 23 can move downward such that their main bodies 232 will move to the narrower part of the wedge shaped gaps 231, as shown in figure 4B. In that position the friction of the main bodies 232 of the third braking members 23 prevent rotation between the first braking member 21 and the second braking member 22, and thereby the frame 9 and the load carrier 10.
The invention has thus been described by means of a preferred embodiment. It is to be understood, however, that this disclosure is merely illustrative. Various details of the structure and function were presented, but changes made therein, to the full extent extended by the general meaning of the terms in which the appended claims are expressed, are understood to be within the principle of the present invention. The description and drawings shall be used to interpret the claims. The claims should not be interpreted as meaning that the extent of the protection sought is to be understood as that defined by the strict, literal meaning of the wording used in the claims, the description and drawings being employed only for the purpose of resolving any ambiguity found in the claims. For the purpose of determining the extent of protection sought by the claims, due account shall be taken of any element which is equivalent to an element specified therein.

Claims

An apparatus for transporting a load from a first to a second level, in particular a stairlift, comprising:
a frame which is displaceable along a rail and which is provided with support, guide and drive means arranged to engage the rail,

a load carrier which is rotationally mounted on said frame to be rotated around a horizontal axis, and

means for maintaining the load carrier in a predetermined rotational position relative to the direction of gravity, which position-maintaining means comprise at least one adjusting motor arranged to rotate the load carrier relative to the frame around said horizontal axis,

wherein said apparatus further comprises an emergency rotation blocking arrangement for preventing said rotation between the load carrier and said frame, said rotation blocking arrangement comprising:
a first braking member rigidly connected to one of said frame and said load carrier,

a second braking member rigidly connected to the other one of said frame and said load carrier,

at least one third braking member arranged between said first braking member and said second braking member,

wherein said first braking member has a primary braking surface which is strip shaped and extends along at least a section of a circle around said axis,

wherein said second braking member has at least one secondary braking surface which extends at a distance from said primary braking surface at an angle in such a manner that the distance between the two surfaces varies, thereby forming a substantially wedge shaped gap between the primary and secondary surfaces having a wider part and a narrower part, the wedge shaped gap widening in a tangential direction around said axis,

wherein in a normal operation mode said third braking member is held in a fixed position relative to said second braking member by a retaining member such that it extends in the wider part of said wedge shaped gap where it cannot engage both the primary and secondary braking surfaces at the same time, and

wherein in a braking operation mode said retaining member is moved relative to said second braking member such that said third braking member is allowed to move to the narrower part of said wedge shaped gap, thereby engaging both the primary and secondary braking surfaces and blocking rotation of the second braking member in said tangential direction relative to the first braking member.
The apparatus according to claim 1, wherein said second braking member comprises at least two secondary braking surfaces, being at least one first secondary braking surface and at least one second secondary braking surface, said at least one first secondary braking surface forming a first substantially wedge shaped gap widening in a first tangential direction around said axis, and said at least one second secondary braking surface forming a second substantially wedge shaped gap widening in a second tangential direction around said axis, said second tangential direction being the opposite of said first tangential direction, and said at least one third braking member being allowed by said retaining member in said braking operation mode to move to a narrower part of one of said first and second substantially wedge shaped gaps, thereby allowing said at least one third braking member to block rotation of the second braking member in either tangential direction relative to the first braking member.
The apparatus according to claim 2, wherein said at least first secondary surface and said at least second secondary braking surface form two separate substantially wedge shaped gaps, and said at least one third braking member are at least two separate third braking members, each extending in a respective substantially wedge shaped gap.
The apparatus according to claim 1, 2 or 3, wherein said blocking arrangement comprises a multitude of first and secondary braking surfaces forming substantially wedge shaped gaps and a multitude of third braking members, each extending in a respective substantially wedge shaped gap.
The apparatus according to any of the previous claims, wherein said primary braking surface is at least a section of a cylindrical surface.
The apparatus according to any of the previous claims, wherein said at least one third braking member has the form of a cylinder, and the axis of said cylinder extends parallel to both the primary and secondary braking surfaces.
The apparatus according to any of the previous claims, wherein the wider part(s) of said wedge shaped gap(s) extend(s) substantially vertically above the narrower part(s) of said wedge shaped gap(s) and said third braking member(s) rest(s) on (a) carrying edge(s) of said retaining member in the normal operation mode.
The apparatus according to claim 7, wherein said retaining member is movable between an upper position in said normal operation mode and a lower position in said braking operation mode.
The apparatus according to any of the previous claims, wherein said retaining member is held in said upper position in normal operation by the force of an electrically powered electromagnet, such that it moves to said lower position in braking operation if electrical power to said electromagnet is absent.
The apparatus according to any of the previous claims, wherein said retaining member is connected to a resilient biasing member which is arranged to move said retaining member from said fixed position in normal operation mode to said braking operation mode.
The apparatus according to any of the previous claims, wherein said first braking member is rigidly connected to said frame and said second braking member is rigidly connected to said load carrier.