(19)
(11)EP 3 722 241 A1

(12)EUROPEAN PATENT APPLICATION

(43)Date of publication:
14.10.2020 Bulletin 2020/42

(21)Application number: 20168442.0

(22)Date of filing:  07.04.2020
(51)Int. Cl.: 
B66B 9/08  (2006.01)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
KH MA MD TN

(30)Priority: 10.04.2019 NL 2022914

(71)Applicant: Otolift Trapliften B.V.
2861 GB Bergambacht (NL)

(72)Inventor:
  • Stam, Michel Alexander
    2861 GB BERGAMBACHT (NL)

(74)Representative: Arnold & Siedsma 
Bezuidenhoutseweg 57
2594 AC The Hague
2594 AC The Hague (NL)

  


(54)AN APPARATUS FOR TRANSPORTING A LOAD FROM A FIRST TO A SECOND LEVEL, IN PARTICULAR A STAIRLIFT


(57) 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 (212) which extends along a circle around said axis,
a second braking member (22) having at least one secondary braking surface (225) comprising two adjacent partial secondary braking surfaces which extend at a distance from said primary braking surface (212) at an angle in such a manner that the distance between the two surfaces (212, 225) varies, said at least braking surfaces forming substantially wedge shaped gaps narrowing from a widest portion in two opposite tangential directions 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 adjacent gaps 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), whereby said third braking members (23) are allowed to move to a narrower part of said adjacent gaps, thereby allowing said third braking members (23) to block rotation of the second braking member (22) in either tangential direction relative to the first braking member (21).




Description


[0001] 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 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, a plurality of third braking members 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 a plurality of secondary braking surfaces which each extend 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 members are each held in a fixed position relative to said second braking member by a retaining member such that they extend in the wider parts of said wedge shaped gaps where the 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 members are allowed to move to the narrower part of said wedge shaped gaps, 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.

[0002] Such an apparatus is described in described in EP 3 326 955 A1, which is incorporated herein by reference. It comprises 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.

[0003] The invention aims at an alternative, more reliable, more robust, and/or a more simple emergency blocking solution.

[0004] To that end each of said secondary braking surfaces comprises two adjacent partial secondary braking surfaces, being a first secondary braking surface and a second secondary braking surface, said at least one first secondary braking surface forming a first substantially wedge shaped gap narrowing from a widest portion in a first tangential direction around said axis, and said at least one second secondary braking surface forming an adjacent second substantially wedge shaped gap narrowing from said widest portion 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 members 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 members to block rotation of the second braking member in either tangential direction relative to the first braking member. In the preferred embodiment said first braking member is rigidly connected to said load carrier and said second braking member is rigidly connected to said frame.

[0005] 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 members move into one of the two adjacent narrow parts of the wedges 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 members 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.

[0006] Preferably said primary braking surface of said first braking member is an inwardly or outwardly facing cylindrical surface. Preferably said secondary braking surfaces of said second braking member form a substantially regular polygon facing said cylindrical primary braking surface, and said plurality of third braking members is distributed along the circumference of said cylinder at equal mutual distances. In the preferred embodiment said primary braking surface of said first braking member is an inwardly facing cylindrical surface and said second braking member extends inside said cylindrical primary braking surface of said first braking member and said secondary braking surfaces of said second braking member are outwardly facing surfaces facing said cylindrical primary braking surface.

[0007] 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 spherical.

[0008] Preferably said retaining member is movable between a horizontally extended position in said normal operation mode and a horizontally retracted position in said braking operation mode. Preferably said retaining member is held in said horizontally extended position in normal operation by the force of an electrically powered electromagnet, such that it moves to said horizontally retracted position in braking operation if electrical power to said electromagnet is absent.

[0009] 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 an emergency rotation blocking arrangement mountable between a displaceable frame and a carrier for a stairlift as shown in figure 1;

Figures 3 and 4 show perspective views of the emergency rotation blocking arrangement of figure 2 in a normal operation mode and a braking operation mode respectively; and

Figures 5 and 6 show front views of the emergency rotation blocking arrangement of figure 2 in a normal operation mode and in a braking operation mode respectively.



[0010] 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 for rotating around a horizontal axis, and arranged in frame 9 and carrier 10 is a level maintaining mechanism consisting of, among other parts, an adjusting motor connected to said shaft 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 emergency rotation blocking arrangement between the frame 9 and the load carrier 10.

[0011] An emergency rotation blocking arrangement as shown in figures 2 and 3 is mounted between the 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.

[0012] The first braking member 21 is rigidly connected said rotatable shaft of the adjusting motor and to the load carrier 10 by means of bolts 211. The first braking member 21 comprises a cylindrical inner surface 212.

[0013] The second braking member 22 is rigidly connected to a hub member 91, which is attached to the frame 9, by bolts extending through holes 221 in said member 22. The second braking member 22 extends inside the cylindrical surface 212 of the first braking member 21, such that it can rotate relative thereto. The second braking member 22 is substantially disc shaped with a substantially octagonal outer circumference. As shown in figures 5 and 6, the octagonal circumferential surface is shaped such that the surface of each part 225', 225" and the cylindrical surface 212 form substantially wedge shaped gaps, having a wider part in the central region and narrower parts in the adjacent lateral regions. In a preferred embodiment as shown each pair of two adjacent parts 225', 225" of the octagonal circumferential surface form a slightly concave surface, which substantially mirrors the opposite concave cylindrical surface 212 of the first braking member 21.

[0014] The third braking members 23 are comprised of cylinders, preferably made of solid metal.

[0015] Substantially disc shaped retaining plates 223, 224 are mounted against each side of the second braking member 22, which are provided with extensions which each extend in front of and behind one of said gaps, in order to prevent axial movement of the third braking members 23 relative to the second braking member.

[0016] The retaining member 24 is made of plastic and comprises a ring 241 having its axis in common with the axes of the first and second braking members 21, 22. Retaining fingers 242 extend from the ring 241 in the axial direction, and are shaped such that they hold the cylindrical third braking members 23 in place relative to the second braking member 22.

[0017] Furthermore an electromagnetic solenoid 248 is provided, which is mounted on the frame 9, and which is connected to the retaining member 24 by means of a yoke 243. When the electromagnetic solenoid is powered it pulls the yoke 243 with the retaining member 24 back in axial direction, whereby the retaining fingers 242 are removed from between the third braking members 23 and the third braking members 23 are allowed to move freely in the tangential direction of the second braking member 22.

[0018] In the normal operation mode (as shown in figures 3 and 5), as long as the third braking member 23 are held in place by the retaining member 24 in the central, widest parts of the so formed gaps between the first braking member 21 and the second braking member 22, the third braking members 23 do not cause a frictional force between the members, whereby the first braking member 21 and the second braking member 22, and thereby the frame 9 and the load carrier 10, can rotate freely relative to each other.

[0019] In the braking operation mode (as shown in figures 4 and 6), when the retaining member 24 is forced to be in the retracted position by the solenoid 248, whereby the third braking members 23 are allowed to move freely in the tangential direction of the second braking member 22, and causing the third braking members 23 to be clamped in the wedge shaped gaps, and possibly being slightly deformed thereby (depending on the force exerted by the speed and the weight of the person on the chair). Thereby the friction 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. A spring member 224, having a shape corresponding to the circumference of the braking member 22, as arranged around the second braking member 22, and is biased in order to exert an outwardly directed force on the third braking members 23, such that they are pushed to reliably make contact with the first braking member 21 in the braking operation mode.

[0020] 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

1. An apparatus (4) for transporting a load from a first to a second level, in particular a stairlift, comprising:

a frame (9) which is displaceable along a rail (3) and which is provided with support, guide and drive means arranged to engage the rail (3),

a load carrier (10) which is rotationally mounted on said frame (9) to be rotated around a horizontal axis, and

means for maintaining the load carrier (10) 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 (9) around said horizontal axis,

wherein said apparatus further comprises an emergency rotation blocking arrangement for preventing said rotation between the load carrier (10) and said frame (9), said rotation blocking arrangement comprising:

a first braking member (21) rigidly connected to one of said frame (9) and said load carrier (10),

a second braking member (22) rigidly connected to the other one of said frame (9) and said load carrier (10),

a plurality of third braking members (23) arranged between said first braking member (210 and said second braking member (22),

wherein said first braking member (21) has a primary braking surface (212) which is strip shaped and extends along at least a section of a circle around said axis,

wherein said second braking member (22) has a plurality of secondary braking surfaces (225) which each extend at a distance from said primary braking surface (212) at an angle in such a manner that the distance between the two surfaces (212, 225) varies, thereby forming a substantially wedge shaped gap between the primary and secondary surfaces (212, 225) 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 members (23) are each held in a fixed position relative to said second braking member (22) by a retaining member (24) such that they extend in the wider parts of said wedge shaped gaps where the cannot engage both the primary and secondary braking surfaces (212, 225) 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 members (23) are allowed to move to the narrower part of said wedge shaped gaps, thereby engaging both the primary and secondary braking surfaces (212, 225) and blocking rotation of the second braking member (22) in said tangential direction relative to the first braking member (21);

characterized in that each of said secondary braking surfaces (225) comprises two adjacent partial secondary braking surfaces (225', 225"), being a first secondary braking surface (225') and a second secondary braking surface (225"), said at least one first secondary braking surface (225') forming a first substantially wedge shaped gap narrowing from a widest portion in a first tangential direction around said axis, and said at least one second secondary braking surface (225") forming an adjacent second substantially wedge shaped gap narrowing from said widest portion 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 members (23) being allowed by said retaining member (24) 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 members (23) to block rotation of the second braking member (22) in either tangential direction relative to the first braking member (21).


 
2. The apparatus according to claim 1, wherein said primary braking surface (212) of said first braking member (21) is an inwardly or outwardly facing cylindrical surface (212).
 
3. The apparatus according to claim 1 or 2, wherein said secondary braking surfaces (225) of said second braking member (22) form a substantially regular polygon facing said cylindrical primary braking surface (212), and said plurality of third braking members (23) is distributed along the circumference of said cylinder at equal mutual distances.
 
4. The apparatus according to claim 2 or 3, wherein said primary braking surface (212) of said first braking member (21) is an inwardly facing cylindrical surface (212) and said second braking member (22) extends inside said cylindrical primary braking surface (212) of said first braking member (21) and said secondary braking surfaces (225) of said second braking member (22) are outwardly facing surfaces (225) facing said cylindrical primary braking surface (212).
 
5. The apparatus according to claim 4, wherein said at least one third braking member (23) has the form of a cylinder, and the axis of said cylinder extends parallel to both the primary and secondary braking surfaces (212, 225).
 
6. The apparatus according any of the previous claims, wherein said retaining member (24) is movable between a horizontally extended position in said normal operation mode and a horizontally retracted position in said braking operation mode.
 
7. The apparatus according to any of the previous claims, wherein said retaining member (24) is held in said horizontally extended position in normal operation by the force of an electrically powered electromagnet (248), such that it moves to said horizontally retracted position in braking operation if electrical power to said electromagnet (248) is absent.
 
8. The apparatus according to any of the previous claims, wherein said first braking member (21) is rigidly connected to said load carrier (10) and said second braking member is rigidly connected to said frame (9).
 




Drawing























REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description