GB2300353A

GB2300353A - Blind person's cane with castor tip

Info

Publication number: GB2300353A
Application number: GB9508975A
Authority: GB
Inventors: Richard Carey
Original assignee: COBOLT SYSTEMS Ltd
Current assignee: COBOLT SYSTEMS Ltd
Priority date: 1995-05-03
Filing date: 1995-05-03
Publication date: 1996-11-06
Also published as: GB9508975D0

Abstract

A cane is fitted with a castor by means of a screw threaded mount 1 having a swivel bearing 3 to which is attached a mount 4 carrying a rough-surfaced nylon ball castor having two halves. An alternative structure is a spherical ball partially held in a housing fitted at the end of the cane. The cane may be freely swung over the ground in any direction due to the castor action.

Description

IMPROVEMENTS IN BLIND PERSONS' CANES Field of the Invention This invention relates to the types of cane used by the blind or those individuals whose vision is severely impaired.

Background "White sticks" (canes used by the blind or those with chronically impaired vision), have been known for decades. The purpose of such a cane, albeit collapsible or not, is to provide its user with an idea of their immediate surroundings. This is done by the user simultaneously tapping and swinging the cane in front of them as they progress, for example along a path. Known as the "two touch" technique, this method of assessment of the surroundings has several drawbacks; swinging the cane between taps does give a reasonably good idea of any obstacles above the ground, however, the "two touch" tap of the cane on the ground between swings, gives only a very limited idea of the nature of the ground about to be traversed. Obviously, clearer warning of curbs, puddles, pot holes etc. would be of tremendous advantage to the user of such a cane.

One solution to this problem has been to develop a rubberised tip that is free to rotate about its longitudinal axis and adapted to be fitted to the base of the cane. With such a device, the user no longer has to tap the cane, he simply has to swing the cane along the ground as he moves. This type of device also overcame the problem of wrist strain caused by the incessant tapping of the cane as the user moved along.

However all of these attachments are prone to excessive wear. The side to side swinging of the cane along the ground is not the main cause of this wear, it is the constant rubbing of the tip along the ground that is substantially oblique to the axis of rotation of the rotating tip that is the problem. This problem is usually overcome by simply replacing the tip at regular intervals, nevertheless, this can be both tedious and expensive over time. Another problem associated with the current design of rotating tip is that grit and general dirt can relatively easily find their way into the bearings of the rotating tip, either clogging the mechanism and/or reducing the lifetime of the bearing.

It is an object of the invention to overcome both the problem of dirt entering the bearing and prolonging the lifetime of the tip.

Summarv of the Invention According to the invention, this problem is solved by using a cane incorporating a castor tip.

Preferably the anti-friction bearing axis of the castor is substantially coaxial with the longitudinal axis of the cane in use. This has the advantage of providing the user with a substantially continuous and smooth castor contact across the ground during the side to side rolling swing of the cane.

More preferably still, that part of the castor that is in continuous contact with ground is substantially spherical in nature. Known as a ball castor this has the advantage of allowing both substantially continuous and smooth movement of the cane along any direction substantially within the plane of the ground/contact surface.

Advantageously, that part of the castor that is designed to be in contact with the ground (or any other contact surface), is substantially made from either, the material known commercially as Nylon 66 or alternatively, from the material known commercially as Nylon 6. This has the advantage of being one of the most wear resistant polymers known and is also extrudible using conventional extrusion techniques, thereby lending itself to relatively cheap mass scale production.

Preferably the anti-friction bearing supporting the ball castor is protected from dirt/grime ingress through the use of a protective covering. This has the advantage of prolonging the life of the anti-friction bearing by preventing the ingress of dirt and grime into the bearing causing unnecessary wear of the bearing.

Preferably the cane end supporting the castor is provided with a screw thread to enable the castor to be integrally assembled into or onto the cane. This has the advantage of providing the user of such a device (who will be either blind or who will have severely impaired vision) with a readily felt means of attaching and removing the castor.

The invention includes within its scope a cane incorporating a castor tip substantially as herein described with reference to and as illustrated by any appropriate selection or combination of the accompanying drawings, as this represents to the applicant, currently the best method of putting the invention into operation.

Brief Description of the Drawings Preferred embodiments of the present invention will now be more particularly described by way of examples with reference to the accompanying drawings wherein: Figure 1 shows in perspective a cane attachment according to one embodiment of the invention; Figure 2 shows an exploded representation of the internal workings of the unit shown in Figure 1.

Description of the Preferred Embodiment Throughout this specification the use of the word integral, will mean either, integrally formed constructions or integrally assembled constructions.

Furthermore, the word castor will be deemed to have a broad interpretation covering any such arrangement that allows a "castoring effect", i.e, any wheel or substantially spherical object attached by design to a larger body to enable that body to move in substantially any direction within substantially the same plane.

Referring to Figures 1 and 2, there is shown a screw threaded means of attachment (1) to the cane. There is also shown a ball castor (2), an antifriction bearing (3), and that portion of the ball castor (4) that is journalled into the anti-friction bearing (3).

In this embodiment (and as illustrated by Figures 1 and 2), there is provided a screw thread means for attaching the castor to the cane. Other means of attaching a castor to a cane can be selected without further inventive thought by the intended addressee of this specification and without departing from the scope of the invention; for example, one could envisage a progressively sliding friction fit of the castor to the cane. Alternatively, one can envisage push button or spring tensioned release fit mechanisms.

In another embodiment, the centre of the ground/surface engaging part of the castor is substantially coincident with the longitudinal axis of the cane when in use. That part of the castor that comes into contact with the ground/surface (2), in use, is substantially spherical. Of course, a number of modifications can be made without departing from the scope of the invention. For instance, in Figures 1 and 2 as illustrated, both halves of the ground/surface engaging part of the castor (2) have been so constructed so that both halves rotate together. Independent rotation of each half of the ground/surface contacting part of the castor can be envisaged. Furthermore, the anti-friction bearing (3), could be selected from applicable forms of known bearings, for example, roller and ball bearings. That portion of the castor (4) that is journalled into the bearing (3), is made of the same material as (2), nevertheless, the materials from which this component can be constructed from may be selected without further inventive thought by the intended skilled addressee in the field of polymer or materials science.

Apart from the anti-friction bearing (3) the embodiment illustrated in Figures 1 and 2, essentially depicts a castor tip constructed from Nylon 66.

This particular material was chosen because of its high wear resistance and ease of extrusion (with a view to mass production). Other materials can be used and the skilled addressee of this specification is referred to the fields of polymer and/or materials science for suitable alternatives. The size of the ground/surface engaging part of the castor as illustrated in Figures 1 and 2, is substantially two to three times the diameter of the cane that it is intended to be used with. The weight of the cane attachment can be varied in many ways (to alter the sensitivity of the device) and one of the ways would be to alter the diameter of the ground/surface engaging portion of the castor. Another would be to use composite materials, for example a high density core and a wear resistant but lighter outer coating for the ground/surface engaging portion of the castor.

In an alternative embodiment (not illustrated), the anti-friction bearing (3), as illustrated in Figures 1 and 2 is protected from the ingress of "foreign bodies" (dirt/grime), by the introduction of a shield surrounding that part of the castor that is journalled into the anti-friction bearing. This embodiment has been described by way of example only and modifications within the scope of the invention can still be conceived of for example, the shield can extend from the edges of the anti-friction bearing to that part of the castor that it is journalled into the anti-friction bearing itself, without actually coming into contact with it. In both instances, it is envisaged that the shield is made of either similar material to the majority of the castor or either metal, or other plastics material.In yet another embodiment, the shield extends from substantially the anti-friction bearing and partially encloses the ball castor. This arrangement will protect the anti-friction bearing from the ingress of dirt/grime and will offer protection to the neck of that portion of the ball castor that is journalled into the anti-friction bearing against excessive lateral forces applied to the ball castor in use.

In yet another alternative embodiment (not illustrated), the ground/surface engaging portion of the castor comprises a substantially spherical ball partially maintained within a housing, the housing being adapted to be fitted to the end of a cane. The housing is so designed to allow rotation of the ball in substantially any direction substantially within a plane of the ground/surface that the ball is in contact with, in use. In this embodiment, the centre of the ball is substantially coaxial with the longitudinal axis of the cane in use.

In a further embodiment, (not illustrated), a further anti-friction bearing (or alternatively a bush) could be introduced into the ball castor itself to encourage rotation of the ball castor about an axis substantially parallel with the ground/surface in the ball castor's normal attitude of operation.

It is envisaged, that in all embodiments, the ground/surface engaging part of the castor is rough. By "rough" we mean so surface-finished as to tend to resist slippage when the castor engages the ground in use.

Claims

1. A cane incorporating a castor tip.

2. A cane as claimed in Claim 1 characterised in that the anti-friction bearing axis of the castor is substantially coaxial with the longitudinal axis of the cane in use.

3. A cane as claimed in either Claim 1 or Claim 2 characterised in that part of the castor that is in continuous contact with the ground is substantially spherical in nature.

4. A cane as claimed in any of the preceding claims characterised in that part of the castor that is designed to be in contact with the ground (or any other contact surface), is substantially made from either the material known commercially as nylon 66 or alternatively, from the material known commercially as nylon 6.

5. A cane as claimed in any of the preceding claims characterised in that the anti-friction bearing supporting the ball castor is protected from dirt/grime ingress through the use of a protective covering.

6. A cane as claimed in any of the preceding claims characterised in that the cane end supporting the castor is provided with a screw thread to enable the castor to be integrally assembled into or onto the cane.

7. A cane incorporating a castor tip substantially as herein described with reference to and as illustrated by any appropriate selection or combination of Figures 1 and 2 of the accompanying drawings.

Amendments to the claims have been filed as follows CLAIMS 1. A cane used by the blind or those with chronically impaired vision directly incorporating a caster tip, the longitudinal axis of the cane passing through substantially the centre of the ground/surface engaging part of the caster when in use.

2. A cane as claimed in Claim 1 characterised in that the cane incorporates an anti-friction bearing.

3. A cane as claimed in Claim 2 characterised in that the anti-friction bearing axis of the castor is substantially coaxial with the longitudinal axis of the cane in use.

4. A cane as claimed in any of the preceding claims characterised in that part of the castor that is in continuous contact with the ground is substantially spherical in nature.

5. A cane as claimed in any of the preceding claims characterised in that part of the castor that is designed to be in contact with the ground (or any other contact surface), is substantially made from either the material known commercially as nylon 66 or alternatively, from the material known commercially as nylon 6.

6. A cane as claimed in any of the preceding claims characterised in that the anti-friction bearing supporting the ball castor is protected from dirt/grime ingress through the use of a protective covering.

7. A cane as claimed in any of the preceding claims characterised in that the cane end supporting the castor is provided with a screw thread to enable the castor to be integrally assembled into or onto the cane.

8. A cane incorporating a castor tip substantially as herein described with reference to and as illustrated by any appropriate selection or combination of Figures 1 and 2 of the accompanying drawings.