Patent Application
20240101393
This application claims priority to Netherlands patent application serial number 2033120, filed Sep. 23, 2022, titled “Apparatus for Transporting a Load, in Particular a Stairlift,” the entirety of which application is incorporated by reference herein.
The present invention relates to an apparatus for transporting a load, in particular a stairlift.
In such apparatus, particularly a stairlift, a load is transported along a rail from a first position (e.g., first level) to a second position (e.g., second level). Generally, a frame is provided which is displaceable along the rail, and a load carrier is rotationally mounted on the frame. The load carrier can be rotated with respect to the frame, for instance about a horizontal axis. Accordingly, the load carrier can be configured to remain level, whilst the frame moves along the rail which can contain various gradients along its path. In other words, the load carrier preferably maintains a substantially fixed rotation with respect to a direction of the force of gravity, whilst the frame can follow the gradient of the rail. The load carrier can be rotated by means of a motor which is connected to the frame, wherein the rotation shaft of the motor is connected to the load carrier. The motor is for instance an electric motor.
As a stairlift can be used to transport persons as a load, it is important that in case of a failure (e.g., power outage, motor issues) the load carrier does not freely rotate with respect to the frame, as this could cause the load (e.g., a person) to fall off the load carrier (e.g., chair) which may cause injury. Accordingly, such stairlift is generally provided with a rotation blocking device configured to block rotation of the load carrier with respect to the frame in case of emergency, or in a resting position (e.g., unpowered state), or the like. An example of such device is described in patent document WO 2021/219488 A1.
In practice it appears that due to play and/or flexibility (e.g., caused by wear and/or fatigue) in the assembly of the load carrier, rotation blocking device, and/or frame, some relative movement between the load carrier and the frame may be possible in the locked state of the rotation blocking device (also referred to as the braking operation mode). Such movement may be effected by, for instance, loading or unloading of the load carrier. In certain cases, such movement may cause the rotation blocking device to get stuck or jammed which prevents proper functioning of the apparatus.
It is an object of the present disclosure, amongst others, to at least partially mitigate the issue of improper functioning of the apparatus, as explained above.
In view of the above, according to a first aspect of the present disclosure, an apparatus for transporting a load is provided, in particular a stairlift, the apparatus comprising a frame which is displaceable along a rail, a load carrier which is rotationally mounted on the frame to be rotated around a horizontal axis, an adjusting motor arranged to rotate the load carrier relative to the frame around the horizontal axis, a rotation blocking device for blocking a rotational movement of the load carrier with respect to the frame in a braking operation mode of the rotation blocking device, and a decoupling means configured to decouple the load carrier from the rotation blocking device and/or the frame from the rotation blocking device, such that a limited amount of movement of the load carrier and/or the frame with respect to the rotation blocking device is allowed in the braking operation mode of the rotation blocking device, and a resilient member for resisting at least part of said movement of the load carrier and/or the frame with respect to the rotation blocking device.
The above apparatus is capable of reducing the chance of improper functioning of the apparatus caused by play and/or flexibility between the load carrier and the frame (e.g., due to wear in the assembly of the apparatus) in the braking operation mode of the rotation blocking device. By allowing a limited amount of movement of the load carrier and/or frame with respect to the rotation blocking device, due to the decoupling means, and concurrently resisting at least part of said movement by means of a resilient member, the force inflicted on the assembly by the movement is at least partially absorbed, such that the force is not fully and directly applied to the rotation blocking device, which thus prevents improper functioning (e.g., due to jamming of the rotation blocking device) as described above.
For instance, the rotation blocking device may be in braking operation mode during standstill (e.g., when the apparatus is powered down) or during an emergency stop. Loading and unloading of the load carrier during standstill may cause rotational or translational movement of the load carrier with respect to the frame (e.g., due to play in the adjusting motor, which may be caused by wear). In the prior art, the rotation blocking device may become increasingly stuck (e.g., due to tightening and/or deformation of braking components) due to the force applied on the rotation blocking device caused by the rotational movement, thus leading to improper functioning or even malfunctioning. Loading of the load carrier may for instance entail a person sitting down in the chair (i.e., on the load carrier) at an offset from the rotation axis of the chair (e.g., the rotation axis of the adjusting motor), thus applying a rotational force and movement to the chair and therefore also to the rotation blocking device.
The decoupling means and resilient member of the apparatus according to the first aspect of the disclosure provides a degree of compensation of forces applied to the rotation blocking device through the load carrier. Accordingly, the effect of rotational forces on the rotation blocking device caused by loads applied to the load carrier, particularly in the braking operation mode, is effectively decreased, and in turn the chance of improper functioning (e.g., jamming of the rotation blocking device) is lowered.
As explained above, decoupling means allow a limited amount of movement of the load carrier and/or the frame with respect to the rotation blocking device in the braking operation mode. Particularly, the limited amount of movement may include rotational movement and/or translational movement, such as axial and/or radial movement. The resilient member resists at least part of said limited amount of movement, which may thus include at least part of the rotational movement, and/or at least part of the translational movement, such as at least part of axial and/or radial movement. In other words, rotational movement and/or translational movement, such as axial and/or radial movement, are considered potential parts of said limited amount of movement. In certain examples, the limited amount of movement may include only one of rotational or translational movement. In further examples, the resilient member may resist only one of rotational or translational movement, or even only a part of the aforementioned movements (such as only the radial part of the translational movement.
Preferably, in the apparatus of the first aspect, the decoupling means and/or the resilient member are at least partially integrated in the rotation blocking device. In this context, being integrated in the device also encompasses being mounted on the device, et cetera, as long as at least part of the decoupling means are connected to, provided in, or engaged in any way with the rotation blocking device.
Preferably, in the apparatus of the first aspect, the resilient member is configured for resisting a rotational movement of the load carrier with respect to the frame around the horizontal axis, as part of said limited amount of movement. In other words, the limited amount of moment may include said rotational movement, i.e., a limited amount of rotational movement, of the load carrier and/or the frame with respect to the rotation blocking device, around the horizontal axis or optionally another relevant axis about which the load carrier, rotation blocking device and/or frame can be moved. It is conceivable that the resilient member resists said rotational movement, but not another movement, such as another rotational movement or a translational movement. For instance, the resilient member resists (e.g., absorbs) movement of the load carrier and/or frame in rotation (e.g., in tangential direction with respect to the horizontal axis), but not in translation (e.g., in radial direction with respect to the horizontal axis). In an example, the rotation blocking device specifically blocks rotation of the load carrier with respect to the frame in the braking operation mode, which may for instance be effected by friction between elements of the rotation blocking device. Accordingly, additional torque on the rotation blocking device, due the aforementioned rotational movement of the load carrier, in the braking operation mode, may increase the friction between such elements. The friction may in certain cases become relatively large, such that the rotation blocking device becomes stuck, i.e., it becomes relatively difficult to get the rotation blocking device out of its braking operation mode and back into a normal operation mode wherein the load carrier and frame are allowed to rotate with respect to each other. Thus, by absorbing at least part of the force caused by the rotational movement, this issue can be at least partially mitigated.
Preferably, in the apparatus of the first aspect, the decoupling means comprises mounting holes, provided in the rotation blocking device for connecting the rotation blocking device with the frame and/or the load carrier, the mounting holes being elongated in a tangential direction around the horizontal axis, for allowing said rotational movement. It is preferred that the resilient member is provided in at least one of the mounting holes. For instance, mounting elements (e.g., bolts or rods) may extend in or through the mounting holes for connecting the rotation blocking device with the frame and/or the load carrier. Due to the elongate shape of the mounting holes, the frame and/or load carrier are allowed to rotationally move with respect to the rotation blocking device in the braking operation mode. Preferably, the elongate shape of the mounting holes enables a rotation of the load carrier and/or the frame with respect to the rotation blocking device, about the horizontal axis, of a specified number of degrees in both directions (i.e., in clockwise and counterclockwise directions). For example, the specified number of degrees may be between 0 and 20.0 degrees, such as 2.0, 4.0, 6.0, 8.0, 10.0, 12.0, 14.0, 16.0, or 18.0 degrees, or any value in between.
Preferably, in the apparatus of the first aspect, the load carrier is connected to the adjusting motor by means of fastening elements. The rotation blocking device may comprise a first braking member, configured to be locked and unlocked relative to the frame by the rotation blocking device in the braking operation mode, the first braking member being interposed between the load carrier and the adjusting motor. The mounting holes of the decoupling means may include fastening holes provided in the first braking member which are configured to allow the fastening elements to pass through the first braking member. The mounting holes are thus elongated, such that the assembly of the adjusting motor, which may be mounted to the frame, and the load carrier are allowed to rotate by a limited amount with respect to the first braking member. Preferably, the resilient member is provided in at least one of the fastening holes. The resilient member may be arranged in the at least one fastening hole to engage the respective fastening element in the tangential direction and an inner surface of the at least one fastening hole.
Preferably, in the apparatus of the first aspect, an alignment pin is arranged on the adjusting motor, wherein the mounting holes of the decoupling means include an alignment hole provided in the first braking member which configured to receive the alignment pin, and the resilient member is arranged in the alignment hole to engage the alignment pin in the tangential direction and an inner surface of the alignment hole.
The elongated shape of the fastening holes and/or alignment hole allows for some rotational movement between the first braking member and the load carrier. Accordingly, when a rotational force is applied to the load carrier in the locked state, the fastening elements and/or the alignment pin can move within the elongated holes in tangential direction, such that a relatively small relative rotational movement of the load carrier with respect to the first braking member is possible. The resilient member resists this relative rotational movement when the first braking member is locked. In addition, the resilient member causes the alignment pin to be re-centered in the alignment hole upon the first braking member being unlocked, and/or causes a re-centering of the fastening elements in the fastening holes. Naturally, in case the rotational force is removed before the first braking member is unlocked (in a normal operation mode of the rotation blocking device), the resilient member will re-center the pin and/or fastening elements (and thus the load carrier) with respect to the first braking member as well. In other words, the load carrier is allowed to rotate slightly with respect to the rotation blocking device in a braking operation mode, and the load carrier and the first braking member are automatically re-centered with respect to each other in a normal operation mode wherein the first braking member is unlocked. Accordingly, the issue of improper functioning of the rotation blocking device is effectively mitigated.
Preferably, in the apparatus of the first aspect, the rotation blocking device comprises two resilient members, each engaging the alignment pin and opposite inner surfaces of the alignment hole, and/or the at least one fastening element and opposite inner surfaces of the associated fastening hole. Preferably, the two resilient members are substantially identical, such that the alignment pin and/or at least one fastening element is biased towards the center of, respectively, the alignment hole and/or fastening hole.
Preferably, in the apparatus of the first aspect, the resilient member is a spring, preferably a compression spring. The spring can for instance be made of a metal, or a plastic, fiber-reinforced plastic, an elastic material such as rubber, or other suitable materials.
Preferably, in the apparatus of the first aspect, the rotation blocking device further comprises spacers located in the fastening holes which are configured to be movable within the fastening holes in the tangential direction and to receive the fastening elements. The spacers essentially act as bearing within the fastening holes, such that the fasteners do not directly contact the inner surfaces of the fastening holes. This may prevent damage to the fastening holes, for instance when the fastening element have sharp protrusions, such as external screw thread.
Preferably, in the apparatus of the first aspect, the first braking member is shaped as an annulus and is substantially concentric, and preferably coaxial, with the horizontal axis. The horizontal axis is preferably coaxial with a shaft of the adjustment motor. Preferably, a shaft of the adjustment motor extends through the center of the annulus-shaped first braking member, such that a distal end of the shaft, distal to the adjustment motor, can be connected with the load carrier.
Preferably, in the apparatus of the first aspect, the rotation blocking device further comprises a second braking member connected to the frame, a third braking member arranged between the first braking member and the second braking member, and a movable retaining member which holds the third braking member and which is arranged to be moved relative to the second braking member, wherein the first braking member has a primary braking surface which is strip shaped and extends along at least a section of a circle around the horizontal axis, wherein the second braking member has a secondary braking surface which extends at a distance from the primary braking surface at an angle in such manner that the distance between the two surfaces varies, thereby forming a substantially wedge-shaped gap between the primary surface and the secondary surface having a wider part and a narrower part, the wedge-shaped gap widening in the tangential direction around the horizontal axis, wherein in a normal operation mode of the rotation blocking device, wherein the first braking member is unlocked relative to the frame, the third braking member is held in a fixed position relative to the second braking member by the retaining member such that it is positioned in the wider part of the wedge-shaped gap where it cannot engage both the primary braking surface and the secondary braking surface at the same time, and wherein in the braking operation mode of the rotation blocking device, wherein the first braking member is locked relative to the frame, the retaining member is arranged to be moved relative to the second braking member such that the third braking member moves to the narrower part of the wedge-shaped gap, thereby engaging both the primary braking surface and the secondary braking surface and blocking rotation of the second braking member in the tangential direction relative to the first braking member.
The resilient member and decoupling means, which may include the elongated fastening holes and alignment hole of the first braking member, aid in preventing the third braking member to become increasingly jammed in the narrower part of the wedge-shaped gap.
Preferably, in the apparatus of the first aspect, the movable retaining member is designed such that it forces the third braking member to move to the narrower part of the wedge-shaped gap when the retaining member is moved relative to the second braking member in the braking operation mode. In other words, the movable retaining member can be actuated so as to engage and disengage the braking action of the rotation blocking device, by actively moving the third braking member.
Preferably, in the apparatus of the first aspect, the rotation blocking device 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. This may provide redundancy as well as the possibility to block rotation in both rotational directions.
Preferably, in the apparatus of the first aspect, the third braking member has the form of a cylinder, and the axis of the cylinder extends parallel to both the primary and secondary braking surfaces.
Preferably, in the apparatus of the first aspect, the retaining member is held in position in normal operation by the force of an electrically powered electromagnet. Preferably, when the electromagnet is not powered, the retaining member automatically returns to its position in the braking operation mode. Accordingly, in case of power outage, the rotation blocking device automatically blocks rotation of the load carrier with respect to the frame.
Preferably, in the apparatus of the first aspect, a resilient biasing member is arranged to move the retaining member from the fixed position in normal operation mode to the braking operation mode. This biases the retaining member to its position in the braking operation mode, and in turn thus biases the third braking member into its position in the braking operation mode, wherein the third braking member moves to the narrower part of the wedge-shaped gap, thereby engaging both the primary braking surface and the secondary braking surface and blocking rotation of the second braking member in the tangential direction relative to the first braking member.
Preferably, in the apparatus of the first aspect, the frame is provided with support, guide and drive means arranged to engage the rail. Suitable means are known to the skilled person to allow the frame to move along the rail.
Preferably, the apparatus of the first aspect further comprises position-maintaining means for maintaining the load carrier in a predetermined rotational position relative to the direction of gravity, which position-maintaining means comprise at least the adjusting motor. The position-maintaining means may further comprise an orientation sensor, such as a rotary sensor, accelerometer, proximity sensor, or the like, from which the rotational position of the load carrier with respect to the direction of gravity may be determined, either directly or indirectly. The position-maintaining means may for instance comprise a controller, which is configured to receive information from the orientation sensor, and on the basis of this information control the adjusting motor for maintaining the load carrier in the predetermined rotational position.
In a second aspect of the present disclosure, the apparatus is a stairlift, which is preferably configured to transport the load from a first level to a second level. Preferably, the first level is the bottom of a staircase, and the second level is the top of the staircase.
The present invention will hereinafter be elucidated by means of illustrative examples with reference to the attached drawings, wherein:
Chair 10 is connected to frame 9 by a rotatable shaft and fixation means 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 so that the position of chair 10 can be kept constant at all times irrespective of the inclination of rail 3.
The first braking member 21 comprises a cylindrical outer surface 212 (see
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 frame 9 by bolts 221 extending through holes 222. A guide ring 224, which encloses the first braking member 21 in the axial direction, is provided on each side of the second braking member 22.
The second braking member 22 comprises recesses 223 in its inner circumferential wall around the cylindrical outer surface 212 of the first braking member 21, such that the surface of said recesses face the outer surface 212. As shown in
The third braking members 23 have a cylindrical main body and a shaft extending from both ends. The holders 241 of the retaining member 24 have holes 249 in which the shafts of the third braking members 23 extend. The braking members 23 can freely rotate around the shafts.
The retaining member 24 comprises two holders 241, two lateral arms 242, a link 243 and a shaft 244. The shaft 244 is mounted on the load carrier 10 in such a manner that it can move in its axial direction, which direction is perpendicular to the horizontal axial direction of the first braking member 21 and the second braking member 22, and which axial direction is, in the example as shown, the vertical direction. The link 243 is attached to the shaft 244 and extends perpendicular to the shaft and is allowed to rotate around the axis of the shaft 244. One end of each of the two lateral arms 242 is attached to the outer end of the link 243 in such a manner that they can rotate around a horizontal axis which is parallel to the horizontal axial direction of the first braking member 21 and the second braking member 22, and such that they can rotate about an axis which is parallel to said axis of the shaft 244. The other outer ends of the lateral arms 242 are each attached to a respective holder 241, in such a manner that the holders 241 can rotate with respect to the arms 242 about an axis which is parallel to the horizontal axial direction of the first braking member 21 and the second braking member 22.
The holders 241 are for instance made of a flexible material, such as a flexible plastic material, such that they can easily deform when forces are exerted on different parts of the holder 241, in particular by the third braking members 23.
Detectors such as micro switches 245 detect the angular mutual orientation between the arms 242 and the holders 241, whereby an emergency braking action may be detected, such that the stairlift 4 may be put out of operation until maintenance has occurred.
The shaft 244, the holders 241 and the third braking members 23 that they hold are movable between two respective extreme positions. Two or more biased springs 246 may be provided, of which one end pushes against a third braking member 23, one on the right side and one the left side as seen in
Even though the first braking member 21 and its functions are here shown as being present on the inner ring-shaped member, and the second braking member 22 and its function are here shown as being present on the outer ring-shaped member, the locations along with the functions of the first and second braking member 21, 22 may be envisaged to be switched, such that, for example, the first braking member 21 and its functions are embodied by the outer ring-shaped member and the second braking member 22 and its functions are embodied by the inner ring-shaped member.
In the normal operation mode, as shown in
As shown in
In the emergency braking operation mode the electromagnet is also unpowered, for instance in reaction to a signal from a sensor that detects tilting of the load carrier, and the retaining member 24 with the holders 241 is first forced towards the lower position by the spring 246, as in the resting mode of
Said movement of the third braking members 23 will cause their holder 241 to move and thereby also move the other holder 241 of the retaining member 24 with the other third braking members 23 as shown in
Thereby the undesired rotation of the load carrier 10 is stopped.
The flexibility of the holders 241 allow that in the braking operation mode all the third braking members 23 in the respective holder can and will be engaged by the surface 212 of the first braking member 21 and the respective surfaces 223 of the second braking member 22, as they are not necessarily held in a mutually fixed position as would be the case with a stiff retaining member.
In
The first braking member 21 is provided with fastening holes 214E which are elongated as compared to the holes 213 of
The first braking member 21 is further provided with two alignment holes 215 which are configured to receive alignment pins 150 of the adjustment motor. The alignment holes 215 are elongated in tangential direction T, such that the alignment pins 150 can move in tangential direction T relative to the first braking member 21. The alignment pins 150 are further biased towards the center of the alignment holes 215 through resilient members, particularly compression springs 216. As both the fastening elements 213 positioned through the spacers 2140 and the alignment pins 150 are rigidly connected to the adjustment motor, the fastening elements 213 and spacers 2140 are also biased towards the center of the fastening holes 214E.
When the first braking member 21 is locked by engagement of the third braking members 23, a rotational force applied to the load carrier 10 will cause movement of the fastening elements 213 and the alignment pins 150 in fastening holes 214E and alignment holes 215, respectively. This movement is damped through the springs 216 acting against the movement of the alignment pins 150 in the alignment holes 215, until the relevant springs 216 are fully compressed. This means that the effect of the rotational force applied to the load carrier 10 on the clamping of the third braking member 23 between the first and second braking members 21, 22 is decreased, as the rotational force is partially absorbed by the springs 216. Accordingly, a rotational force applied to the load carrier 10 in the braking operation mode of the rotation blocking device is not directly transferred to the braking mechanism formed by the first, second and third braking members 21, 22, 23. Accordingly, the chance that the braking mechanism becomes jammed or stuck to a certain degree or wear such as deformations, due to such rotational force applied to the load carrier 10, is effectively decreased. When the first braking member 21 is released (normal operation mode), the springs 216 cause the alignment pins 150 and fastening elements 213 to re-center in the alignment holes 215 and fastening holes 214E, respectively.
In accordance with the above, regarding
The illustrative embodiments or examples described above are not to be construed as limiting the scope of protection, which is determined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2033120 | Sep 2022 | NL | national |
