Abstract
A stair assistance device for use with a handrail, the device comprising a sleeve engageable with and slideable relative to the handrail, and a brake element to hinder or prevent sliding movement of the sleeve, wherein, when the sleeve is engaged with a handrail, the brake element is resiliently biased towards the handrail, to hinder or prevent movement of the sleeve when the device is not in use.
Claims
1. A stair assistance device for use with a handrail, the device comprising: a sleeve having a handlebar extending therefrom, the sleeve engageable with and slideable relative to the handrail, and a removable pad assembly disposed within an interior of the sleeve, wherein when the stair assistance device is engaged with the handrail, said removable pad assembly is disposed between an internal surface of the sleeve and an outer surface of the handrail, wherein the removable pad assembly comprises a sprung steel backing plate from which an inwardly bent protrusion is formed comprising a spring strip in a portion of a first surface disposed at a first longitudinal end of the backing plate, said spring strip having the first surface bonded with a material having a first coefficient of friction for slidably engaging the outer surface of the handrail while a second surface disposed at a second longitudinal end of the sprung steel backing plate is bonded with a material having a second coefficient of friction, the second coefficient of friction being higher than the first coefficient of friction, wherein when the stair assistance device is engaged with the handrail, said spring strip provides a biasing force against the outer surface of the handrail so that the material with the second coefficient of friction is held in contact with the outer surface of the handrail to hinder or prevent movement of the sleeve relative to the handrail when the device is not in use, and wherein the handle bar is manually movably along the handrail when a user overcomes the biasing force.
2. A stair assistance device according to claim 1 wherein the removable pad assembly is releasably engageable with the sleeve.
3. A stair assistance device according to claim 1 wherein a free end of the spring strip is adjacent an edge of the backing plate.
4. A stair assistance device according to claim 1 wherein the removable pad assembly is releasably held within the sleeve.
5. A stair assistance device according to claim 4 wherein the removable pad assembly is releasably held by adhesion.
6. A stair assistance device according to claim 1 including a further pad assembly which is configured to engage with a different side of the handrail to the removable pad assembly.
7. A stair assistance device according to claim 6 wherein the further pad assembly is engageable with an opposite side of the handrail to the removable first said pad assembly.
8. A stair assistance device according to claim 1 which comprises a plurality of pad assemblies disposed within the sleeve that substantially encloses a handrail, the sleeve being slideably movable along the handrail, said pad assemblies comprising one or more linear springs that produce a force that applies a friction brake against the said handrail and providing a positive force, wherein the handle bar is manually movable up or down the handrail when a user overcomes the positive force.
9. A stair assistance device according to claim 1, wherein when the stair assistance device is engaged with the handrail, said removable pad assembly is disposed within a gap between an internal lateral surface of the sleeve and a lateral outer surface of the handrail.
Description
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS, AND BEST MODE OF THE INVENTION
(1) A specific and non-limiting embodiment of the invention will now be described, strictly by way of example only, with reference to the drawings, of which:
(2) FIG. 1 shows a cutaway view of an embodiment of the device from above;
(3) FIG. 2 shows a pad which may be used in a stair assistance device;
(4) FIG. 3 shows another pad which may be used in a stair assistance device;
(5) FIG. 4 shows a stair assistance device in exploded form;
(6) FIG. 5 shows the forces acting on the stair assistance device when not in use;
(7) FIG. 6 shows the forces acting on the device when the device is moved upwards, along a handrail;
(8) FIG. 7 shows the forces acting on the device when ascending the stairs;
(9) FIG. 8 shows the forces acting on the device when the device is moved downwards, along a handrail; and
(10) FIG. 9 shows the forces acting on the device when descending the stairs.
(11) Referring to FIG. 1, there is shown a stair assistance device, indicated generally at 10. A handle, in the form of handle bar 7 is connected to a sleeve formation 8, and the sleeve formation 8 is engaged (in use) with a handrail 6. Disposed inside the sleeve formation 8, there are pads comprising a pad backing 1, a material with a relatively low coefficient of friction 2 (referred to herein as “low friction material 2”), a material with a relatively high coefficient of friction 3 (referred to herein as “high friction material 3”), a biasing means such as a spring protrusion 4, and an attachment means 5. Each part of the pad may be made of any suitable material—for example, the pad backing may be made of spring steel, the spring protrusion 4 may also be made of spring steel, and may be integral with the pad backing, and the attachment means 5 may be any suitable method of attachment, such as an adhesive with relatively low adhesion properties. This adhesive may be an adhesive applied to the pad backing or the inside of the sleeve, or may be an adhesive carried by a substrate, such as a double-sided adhesive tape.
(12) Alternatively, the pad may be retained in the sleeve by the reactive force of the spring 4, which results from the force transmitted through low friction material 2 when it is in contact with the handrail. Any other suitable retention method may be used; for example, there may be corresponding formations on the pad and the sleeve allowing them to engage with one another, or the pads may be retained by magnets or known fixing methods such as bolts, screws, or clips. In this (preferred) embodiment, the pads are releasably engaged with the sleeve, allowing them to be easily removed or replaced, which is beneficial for cleaning and maintenance purposes.
(13) FIG. 2 shows one embodiment of a pad assembly, referred to herein as “Pad Assembly A”. The backing pad is substantially planar, and has a low friction portion 2, and a high friction portion 3, which are disposed at opposite ends, in the example shown. It will be appreciated that the backing 1, the low friction portion 2 and the high friction portion 3 could be any suitable shape to ensure effective engagement with the handrail 6. For example, the low friction portion 2 and the high friction portion 3 may have a curved surface to engage a handrail with a curved face. The pad assembly may also be provided with any suitable biasing means. The low friction portion 2 and the high friction portion 3 may be attached to the backing 1 by any suitable method, such as bonding, welding, etc.
(14) In this example, the pad assembly comprises a spring steel backing plate 1 onto which are bonded, at opposite ends, two blocks of material with differing coefficient of friction (2 & 3).
(15) FIG. 3 shows another embodiment of a pad assembly, referred to herein as “Pad Assembly B”. The pad includes a protrusion 4, which may be made from any suitable material, such as spring steel, and may be integrally formed with the backing plate. In the example illustrated, the low friction portion 2 is mounted on the protrusion 4. The protrusion itself may function as a leaf spring, or an alternative (separate) spring may be provided. In use, the spring takes up the “free play” between the handrail 6 and the handle bar 7. Controlling the “free play” in this way has been found to provide a superior user experience. It can allow better tactile feedback to the user, and can also be used to retain (“park”) the stair assistance device at the position at which it has been left by the user. To prevent damage to the handrail, the sprung protrusion has a material with a low coefficient of friction (2) bonded to it, while the opposing end of the pad has a material with a high coefficient of friction (3), to act as a brake.
(16) This embodiment of the invention comprises two separate, dissimilar, replaceable pad assemblies ‘A’ and ‘B’, removably attached to the inner surfaces of the sleeve formation 8, by attachment means 5, such as double side adhesive tape, so as to allow maintenance.
(17) As shown in the embodiment of FIG. 4, the end of pad assembly ‘A’ with the high coefficient of friction is desirably placed opposite the spring end of pad assembly ‘B’. This modification provides a number of benefits. 1. Moving the friction materials onto separate backing plates and attaching them to the sleeve with a low adhesive bond (such as double sided tape) allows relatively easy replacement if the braking mechanism shows signs of wear, or if it becomes damaged. 2. The spring built into pad assembly ‘B’ ensures that the braking surfaces of both pads are held in contact with the handrail when the handle bar is at rest, thus keeping the handle bar locked when not being directly manipulated. 3. The inclusion of the spring in pad assembly ‘B’ also provides an improved ‘feel’ to the handle when in operation. 4. The reactive force of the spring acts to retain the pad within the sleeve.
(18) FIG. 5 shows the forces acting on the device at rest (i.e. when not in use). The leaf spring protrusion 4 presses the material with a low coefficient of friction against the handrail, producing an opposing force that causes a slight (clockwise) rotational force, which holds the material with the high coefficient of friction against the handrail on both lateral surfaces, thus effectively locking the handle bar to the handrail by friction. This retains the stair assistance device in the position in which it has been left by the user.
(19) FIG. 6 shows the forces acting when moving the handle bar up the handrail. To move the handle bar up the handrail in preparation to ascend, a greater force ‘A’ is applied to the end of the handle bar furthest from the handrail, while a lesser force ‘B’ is applied nearer the sleeve. The slight (counter clockwise) rotational movement overcomes the action of the sprung steel protrusion until the material with the high coefficient of friction ceases contact with (or is sufficiently ‘released’ from) the handrail, allowing the handle bar to slide up the handrail in ‘C’.
(20) FIG. 7 shows the forces acting when ascending stairs. The user can then pull himself/herself up onto the next stair by pulling against the handle bar, producing an equal force ‘A’ across the handle bar. This action increases the force pressing the materials with a high coefficient of friction against the lateral sides of the handrail, providing support for the user until they are secure on the stair, at which point the handle bar can be moved up the handrail once again until the user has climbed the full length of the staircase.
(21) FIG. 8 shows the forces acting when moving the handle bar down the handrail. When descending the stairs the handle bar is pushed down the handrail by applying a greater force ‘A’ at the sleeve end of the handle bar than the force ‘B’ applied at the other (distal) end. This overcomes the action of the sprung steel protrusion, substantially disengages the material with the high coefficient of friction from the handrail and allows the handle bar to move down the rail.
(22) Finally, FIG. 9 shows the forces acting when descending stairs. When the user steps down they push down against the handle bar with a steady pressure across the bar ‘A’ (the same force ‘A’ would be applied if they fell against the handle bar). This action increases the force pressing the materials with a high coefficient of friction against the lateral sides of the handrail, providing support for the user until they are secure on the next step, when the handle bar can be moved down the handrail once again until the user has descended the full length of the staircase.
(23) When used in this specification and claims, the terms “comprises” and “comprising” and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.
(24) The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.
