GB2539088A

GB2539088A - A connector

Info

Publication number: GB2539088A
Application number: GB1607357.9A
Authority: GB
Inventors: Curtis Brian
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-04-27
Filing date: 2016-04-27
Publication date: 2016-12-07
Also published as: GB201507142D0

Abstract

The invention provides a walking aid having a tubular shaft comprising two tubular shaft portions S2, S3 joined end to end by a connector (C figure 1); the connector comprising a pair of connector elements 2,4, each connector element having a spigot portion 6,14 for securing inside an open end of one of the two tubular shaft portions; the connector elements 2,4 being provided with means (e.g. threaded screw connection) enabling them to be releasably fastened together. The connector elements 2,4 may have opposing flanges 16,8 and a sealing element 24. Another embodiment is also described (figures 9-12) wherein the connectors have formations which align when connected and a locking element which engages said formations and prevents relative rotation of the two connector elements.

Description

A CONNECTOR

This invention relates to a walking aid and to a connector for connecting tubular members forming part of a walking aid such as a crutch or walking strip.

A problem with many walking aids such as crutches is that they are of an awkward size for carrying in cars and on public transport.

The present invention sets out to provide a walking aid that can readily be broken down into smaller components for carrying and then subsequently reassembled as necessary. The invention also sets out to provide a connector that can quickly and simply be "retro-fitted" into existing walking aids so that they can be carried more readily.

Accordingly, in a first aspect, the invention provides a walking aid having a tubular shaft comprising two tubular shaft portions joined end to end by a connector; the connector comprising a pair of connector elements, each connector element having a spigot portion for securing inside an open end of one of the two tubular shaft portions; the connector elements being provided with means enabling them to be releasably fastened together.

The walking aid can be, for example, a crutch or walking stick and typically has a ground-engaging part (foot), and handle or arm rest and a tubular shaft connecting the foot and handle or arm rest. The tubular shaft is typically a metal shaft formed, for example from aluminium and may have a telescopic form of construction to allow the length to be adjusted to suit the user.

The connector comprises a pair of connector elements each of which has a spigot portion for securing inside an open end of one of the two tubular shaft portions. The connector elements are provided with means enabling them to be releasably fastened together. For example, the two connector elements can be configured to provide a threaded connection therebetween. Thus, one connector element may have a threaded shank that engages a correspondingly threaded bore in the other connector element. Alternatively, the pair of connector elements could be provided with fastening means that cooperate to form a bayonet fitting.

The connector elements, when connected together typically form a connector which is able to resist lateral forces (e.g. forces acting to bend the tubular shaft when assembled with the connector) to at least the same extent as the tubular shaft itself. Thus the connector should not act as a weak point in the tubular shaft that would cause buckling of the shaft under the weight of the user of the walking aid. Accordingly, the connector elements may be formed as solid non-hollow elements from a suitable metal material such as steel or aluminium. Alternatively, the connector elements may be hollow but, when they are hollow, the radial thicknesses of the walls of the connector elements are typically at least twice the radial thicknesses of the walls of the tubular shaft portions. More preferably, the thicknesses of the walls of the connector elements are typically at least two and a half times, or at least three times the radial thicknesses of the walls of the tubular shaft portions.

The spigot portions of the connector elements typically extend at least 2 centimetres along the interior of each tubular shaft portion. More usually, the spigot portions of the connector elements extend at least 2.5 centimetres, or at least 3 centimetres, or at least 3.5 centimetres along the interior of each tubular shaft portion.

The spigot portions are typically held inside the tubular shaft portions by means of a tight force fit or friction fit. However, a secondary means of securing the spigot portions inside the tubular shaft portions may be provided. The secondary securing means can take the form of a mechanical fastener such as one or more securing screws or rivets, or an adhesive such as cyanoacrylate adhesive or an epoxy adhesive. Where an adhesive is used, the surfaces of the spigot portions may be roughened or provided with one or more recesses, grooves, ribs or protrusions to provide a better key for the adhesive. In one embodiment, the spigot portions are provided with one or more annular grooves for assisting adhesive bonding.

The connector may be provided with means for preventing inadvertent loosening (e.g. unscrewing) of the joint between the connector elements.

In one particular embodiment, the connector comprises a pair of connector elements each of which has a spigot portion for securing inside an open end of one of the two tubular shaft portions; one connector element having a threaded shank that engages a female thread on the other connector element; wherein the two connector elements have opposing flanges and a sealing element is disposed between the opposing flanges such that on screwing the two connector elements together, the sealing element is compressed between the opposing flanges.

By placing a sealing element between the two flanges so that it is compressed when the two connector elements are screwed together, frictional resistance to the two connector elements being unscrewed from one another is increased thereby reducing or preventing unintended loosening of the joint between the connector elements.

In order to provide increased frictional resistance to unscrewing, one or both of the flanges may be provided with one or more annular grooves such that upon compression, the sealing element is at least partially embedded in an annular groove. For example, the sealing element can be an 0-ring formed from an elastomeric material such as a rubber (which may be either a natural or synthetic rubber), and one or both of the opposed flanges may be provided with an annular groove to accommodate the 0-ring.

As one alternative to an 0-ring, the sealing element may comprise an annular washer that sits about the threaded shank of one connector element and is compressed between the two flanges as the two connecter elements are screwed together. The annular washer is preferably made from a compressible material that deforms under compression. Thus, for example, the annular washer can be made from a polymeric material such as a rubber or from leather. The flanges can be provided with one or more annular grooves (e.g. two or three concentric annular grooves, and in particular two concentric annular grooves) such that compression of the washer causes the washer to deform and bed into the grooves.

It has been found that an arrangement in which the flanges are both provided with an annular groove (and in particular two concentric annular grooves) and the washer is made from a leather material provides particularly good resistance to unintended loosening of the joint between the two connector elements.

In a further embodiment, the connector comprises a pair of connector elements each of which has a spigot portion for securing inside an open end of one of the two tubular shaft portions; one connector element having a threaded shank that engages a female thread on the other connector element; wherein the two connector elements each have formations that can be brought into alignment when the connector elements are screwed together, and wherein a locking element is provided that can engage the said formations to prevent relative rotation of the two connector elements.

In one embodiment, the locking element comprises a latch which is mounted on one of the said formations and can engage the other said formation to hold it in a locked condition.

In another embodiment, the two connector elements have opposing surfaces, each of which has a recess therein such that, when the connector elements are screwed together, the recesses come into alignment to form a channel, and wherein the connector further comprises a locking element insertable into the channel to prevent relative rotation of the two connector elements.

The opposing surfaces within which the recesses are located may be opposing flanges.

The recesses may be, for example, hemi-cylindrical in form so that, when the connector elements are screwed together, the recesses come into alignment to form a cylindrical channel into which a locking element (e.g. a cylindrical locking element) may be inserted. Alternatively, the channel may be rectangular or polygonal in cross section and the recesses shaped accordingly.

The locking element is typically provided with releasable means for holding it in place in the channel. The releasable means can take the form of a resilient element which forms part of or engages the locking element so that the locking element is resiliently biased into the channel. The releasable holding means can, for example, comprise a spring clip which encircles the connector, the locking element extending inwardly from an inner surface of the spring clip.

In order to provide a means of unscrewing the connector elements if the joint has been over-tightened, a laterally-extending arm or side bar may be provided to give more torque. The laterally extending arm or side bar may be removable: for example, it may be inserted through aligned laterally extending holes or passages in a tubular shaft portion and connector element. Both tubular shaft portions and their associated connector elements may be provided with holes or passages for receiving a laterally extending arm or side bar but typically one such arm or bar should suffice.

In addition to providing a walking aid as hereinbefore defined, the invention also provides a connector as defined herein which is suitable for use with a walking aid of the type comprising a tubular shaft.

In a still further aspect of the invention, there is provided a method of modifying a walking aid of a type comprising a tubular shaft; which method comprises cutting the tubular shaft into two tubular shaft portions and inserting into cut ends of the two tubular shaft portions the spigot portions of a connector as defined herein.

Further aspects and embodiments of the invention will be apparent from the claims appended hereto and the apparatus illustrated in the drawings and described below.

Brief Description of the Drawings

Figure 1 is a side view of a walking aid fitted with a connector according to a first embodiment of the invention.

Figure 2 is a side view of a connector according to the invention. Figure 3 is a view from direction D1 of the connector of Figure 2. Figure 4 is a view from direction D2 of the connector of Figure 2.

Figure 5 is a side sectional elevation showing the connector of Figures 2 to 4 in disassembled form.

Figure 6 is a side sectional elevation showing the connector of Figures 2 to 5 connecting together a pair of tubular elements forming part of a walking aid.

Figure 7 is a side sectional elevation showing a connector according to a second embodiment of the invention is disassembled form.

Figure 8 is a side sectional elevation showing the connector of Figure 7 connecting together a pair of tubular elements forming part of a walking aid.

Figure 9 is a side view of a connector according to a third embodiment of the invention.

Figure 10 is a side view of a spring clip for use with the connector of Figure 9. Figure 11 is a side sectional elevation along line 1-1 in Figure 9.

Figure 12 is a side sectional elevation showing the connector of Figures 9 to 11 connecting together a pair of tubular elements forming part of a walking aid.

Detailed Description of the Invention

The invention will now be illustrated but not limited by reference to the specific embodiments shown in the drawings Figures 1 to 12.

Figure 1 shows a walking aid in the form of a crutch which is of generally conventional construction except that it includes a connector of the invention. Thus, the crutch comprises a telescopic tubular pole having an arm rest AR at its upper end and a rubber foot F at its lower end. The lower section S1 is connected to the intermediate section S2, the section S1 having a smaller diameter than the section S2 so that the end of the section S1 can slide along the interior of the section S2 to form a telescopic arrangement that allows the length of the crutch to be varied. A pair of spring loaded retractable lugs (not shown) protruding laterally from both sides of the section 51 can locate in adjustment holes AH to lock the crutch in a desired configuration. The lugs can be depressed to disengage them from the holes to permit the member S1 to slide along the interior of member S2.

A connector C according to a first embodiment of the invention is shown in Figures 2 to 6. The connector comprises a pair of connector elements 2, 4 formed from a metal such as steel or aluminium or a suitably tough engineering plastics material such as polyacetal.

The "female" connector element 2 is of cylindrical form and comprises a spigot portion 6 and an annular flange 8 at one end of the spigot portion 6. The connector element 2 has a hollow interior which is open at both ends, and the interior surface of the connector element 2 bears a thread 10. The spigot portion 6 has a plurality of circumferential grooves 12 (in this case three although fewer or more than three grooves may be present) extending around its outer surface. The circumferential grooves assist in the fixing of the connector element 2 to a tubular element forming part of a walking aid as described below.

An 0-ring 24 formed of a polymeric material such as a nitrile rubber, is located in an annular groove 22 in an axial face of the flange 8 on the female connector 2.

The "male" connector element 4 also comprises a cylindrical spigot portion 14 and has an annular flange 16 at one end of the spigot portion 14. Extending away from the flange in a direction opposed to the spigot portion 14 is a threaded shank 18 having an external thread 19 that complements the internal thread 10 in the interior surface of the connector element 2. The spigot portion 14 has a hollow interior which is open at one end; the end remote from the annular flange 16. The spigot portion 14 also has a plurality of circumferential grooves 20 extending around its outer surface.

The connector can be used to form a joint in a walking aid such as a walking stick or crutch that enables the walking aid to be broken down into shorter components for transport purposes. The connector can be fitted during manufacture of the walking aid or it can be used to convert a standard walking aid.

Thus, for example, a standard crutch comprising a tubular metal shaft can readily be cut into two lengths using conventional cutting tools.

The spigot portion 6 of connector element 4 is then inserted into one of the cut ends of the tubular metal shaft of the crutch so that the cut end abuts against the flange 8. The spigot portion 14 of the connector element 4 is inserted into the other cut end of the tubular metal shaft of the crutch so that the cut end abuts against the flange 16. Each of the spigot portions 6, 14 are of a size such that they fit tightly inside the cut ends of the tubular metal shaft. However, in order to make the fastening more secure, an adhesive such as a cyanoacrylate adhesive or an epoxy adhesive can be coated onto the outer surfaces of the spigot portions 6, 14 so that the adhesive fills the circumferential grooves 12, 20, before the spigot portions are inserted into the cut ends of the tubular shaft.

As an alternative (or in addition to) to using adhesive, mechanical fasteners such as screws or rivets may be used to fasten the spigot portions securely into the cut ends of the metal shaft. For example, holes may be drilled through the two portions of the tubular metal shaft and into the spigot portions 6 and 14 and fasteners such as threaded rivets driven into the hole.

Once the spigot portions of the connector elements 2 and 4 have been securely fastened inside the cut ends of the tubular metal shaft of the crutch, they can be screwed together as shown in Figure 6 to rejoin the two portions of the tubular shaft.

Thus, the connectors of the invention can readily be used to convert a standard walking aid such as a crutch into a two-piece device that can be broken down for carrying but can quickly be reassembled for use at the end of a journey.

When the walking aid has been broken down into two pieces for carrying, the threaded shank 18 can be covered by a cap (not shown) to prevent it from snagging on clothing, car upholstery or other surfaces or cause injury to the user or other people.

A connector according to another embodiment of the invention is shown in Figures 7 and 8. The connector of Figures 7 and 8 is of substantially similar construction to the connector shown in Figures 2 to 6 and is used in the same way. However, the connector of Figures 7 and 8 differs from the connector of Figures 2 to 6 in that each of the opposing end faces 109 and 117 of the flanges 108 and 116 respectively is provided with a pair of concentric annular grooves (111, 113 and 119, 121 respectively). In addition, instead of the 0-ring employed in the embodiment of Figures 2 to 6, a washer 125 is mounted on the threaded shank 118. The washer 125 is formed of a compressible deformable material such as a polymer (e.g. a rubber) or leather. Currently, a leather washer is preferred. When the two halves 102 and 104 of the connector are screwed together, the washer is compressed between the two flanges 108 and 116 and deformed so that it spreads into the annular grooves (111, 113 and 119, 121) as shown in Figure 8. This has the effect of increasing the frictional force of the washer on the two flanges 108 and 116 such that greater torque is required in order to unscrew the connector. Therefore, the joint between the two connector halves is much tighter and the likelihood of the connector halves unexpectedly becoming loose is avoided. In order to assist in the unscrewing of the connector, the male connector element 104 and the portion of the tubular shaft into which it is inserted can be provided with a lateral bore (not shown) for receiving a side bar (not shown).

A connector according to a further embodiment of the invention is shown in Figures 9 to 12.

The connector is generally similar to the connector shown in Figures 1 to 8 in that it comprises a pair of connector elements 202, 204 formed from a metal such as steel or aluminium or a suitably tough engineering plastics material such as polyacetal. The "female" connector element 202 is of cylindrical form and comprises a spigot portion 206 and an annular flange 208 at one end of the spigot portion 206. The connector element 202 has a hollow interior which is open at both ends, and the interior surface of the connector element 202 bears a thread 210.

The "male" connector element 204 also comprises a cylindrical spigot portion 214 and has an annular flange 216 at one end of the spigot portion 214. Extending away from the flange in a direction opposed to the spigot portion 214 is a threaded shank 218 having an external thread 219 that complements the internal thread 210 in the interior surface of the connector element 202.

The connector of Figures 9 to 12 differs from the connectors of Figures 1 to 8 in that the annular flanges 208 and 216 each have a hemi-cylindrical recess 208a, 216a. When the two connector elements 202, 204 are fully screwed together, the two hemi-cylindrical recesses 208a, 216a are aligned and together form a cylindrical channel 223 into which a locking pin 226 can be inserted. The locking pin 226 is mounted on a generally circular or C-shaped spring clip 228 which encircles the connector and holds the locking pin 226 firmly in place. The spring clip 228 can be formed from a suitable metal spring strip, for example spring steel, although it could alternatively be formed from a resilient plastics material. The locking pin 226 is typically formed from a metal such as steel or aluminium, or a suitably tough plastics material.

The locking pin 226 prevents the connector elements 202, 204 from being rotated relative to each other and therefore prevents inadvertent unscrewing of the connector. When the walking aid has been broken down into two pieces for carrying, the spring clip can be secured to the walking aid by virtue of the locking pin engaging one of the adjustment holes AH (see Figure 1) in the walking aid.

The locking pin 226 and channel 223 are shown as being of circular cylindrical shape but it will be appreciated that they could be shaped differently. For example, the locking pin could have a rectangular or polygonal cross section, and the recesses 208a, 216a would be shaped accordingly.

It will readily be apparent that numerous modifications and alterations could be made to the apparatus shown in the drawings without departing from the scope of the claims appended hereto and all such modifications and alterations are intended to be embraced by this application.

Claims

CLAIMSA walking aid having a tubular shaft comprising two tubular shaft portions joined end to end by a connector; the connector comprising a pair of connector elements, each connector element having a spigot portion for securing inside an open end of one of the two tubular shaft portions; the connector elements being provided with means enabling them to be releasably fastened together.
2. A walking aid according to claim 1 which is a crutch or a walking stick.
3. A walking aid according to claim 1 or claim 2 wherein the tubular shaft is formed from a metal.
A walking aid according to any one of claims 'I to 3 wherein the two connector elements are configured to provide a threaded connection therebetween.
5. A walking aid according to claim 4 wherein one connector element has a threaded shank that engages a correspondingly threaded bore in the other connector element.
6. A walking aid according to claim 1 wherein the connector comprises a pair of connector elements each of which has a spigot portion for securing inside an open end of one of the two tubular shaft portions; one connector element having a threaded shank that engages a correspondingly threaded bore in the other connector element; and wherein the two connector elements have opposing flanges and a sealing element is disposed between the opposing flanges such that on screwing the two connector elements together, the sealing element is compressed between the opposing flanges.
A walking aid according to claim 6 wherein one or both of the flanges are provided with one or more annular grooves such that upon compression, the sealing element is at least partially seated in an annular groove.
8. A walking aid according to claim 6 or claim 7 wherein the sealing element comprise an annular washer that sits about the threaded shank of one
9.
10.
11.
12.connector element and is compressed between the two flanges as the two connecter elements are screwed together.

A walking aid according to claim 8 wherein the annular washer is made from leather.

A walking aid according to any one of claims 6 to 9 wherein the flanges are provided with one or more annular grooves such that compression of the washer causes the washer to deform and bed into the grooves.

A walking aid according to claim 10 wherein both flanges are provided with one or two concentric annular grooves.

A walking aid according to any one of claims 1 to 5 which comprises a pair of connector elements each of which has a spigot portion for securing inside an open end of one of the two tubular shaft portions; one connector element having a threaded shank that engages a female thread on the other connector element; wherein the two connector elements each have formations that can be brought into alignment when the connector elements are screwed together, and wherein a locking element is provided that can engage the said formations to prevent relative rotation of the two connector elements.
13. A walking aid according to claim 12 wherein the two connector elements have opposing surfaces, each of which has a recess therein such that, when the connector elements are screwed together, the recesses come into alignment to form a channel, and wherein the connector further comprises a locking element insertable into the channel to prevent relative rotation of the two connector elements.
14. A walking aid according to claim 12 or claim 13 wherein locking element is provided with releasable means for holding it in place in the channel, releasable means taking the form of a resilient element which forms part of or engages the locking element so that the locking element is resiliently biased into the channel.
15. A walking aid according to claim 14 wherein the releasable holding means comprises a spring clip which encircles the connector, the locking element extending inwardly from an inner surface of the spring clip.
16. A walking aid substantially as described herein with reference to the accompanying drawings Figures 1 to 12.
17. A connector which is suitable for use with a walking aid of the type comprising a tubular shaft, the connector being as defined in any one of claims 1 to 16.
18. A method of modifying a walking aid of a type comprising a tubular shaft; which method comprises cutting the tubular shaft into two tubular shaft portions and inserting into cut ends of the two tubular shaft portions the spigot portions of a connector as defined in any one of claims 1 to 17.