A connector

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 ele

Description

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 5 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 10 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 LO connector comprising a pair of connector elements, each connector element CM having a spigot portion for securing inside an open end of one of the two tubular £\j 15 shaft portions; one connector element having a threaded shank that engages a 1” female thread on the other connector element thereby to provide a means of enabling the connector elements to be releasably fastened together; wherein the CO two connector elements each have formations that can be brought into alignment when the connector elements are screwed together, and wherein a locking 20 element is provided that can engage the said formations to prevent relative rotation of the two connector elements. 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, 25 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 30 fastened together, the said means taking the form of a threaded connection therebetween. One connector element has a threaded shank that engages a correspondingly threaded bore (i.e. female thread) in the other connector element. 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 5 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, 10 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 15 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 20 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 25 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. 30 The connector is provided with means for preventing inadvertent loosening (unscrewing) of the joint between the connector elements. According to the invention, 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 5 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 10 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 LO CXI CXI together, the recesses come into alignment to form a channel, and wherein the 15 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 20 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 25 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. 30 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 30 12 25 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 5 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. 10 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 15 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. 20 Figure 2 is a side view of a connector according to the invention. Figure 3 is a side view of a spring clip for use with the connector of Figure 2. Figure 4 is a side sectional elevation along line l-l in Figure 2. Figure 5 is a side sectional elevation showing the connector of Figures 2 to 4 connecting together a pair of tubular elements forming part of a walking aid. 25 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 5. 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 5 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 S1 can locate in adjustment holes AH to lock the 10 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 according to one embodiment of the invention is shown in Figures 2 to 5. CXI CXI 15 20 25 30 The connector 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 spigot portion 206 has a plurality of circumferential grooves 212 (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 202 to a tubular element forming part of a walking aid as described below. 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 spigot portion 214 also has a plurality of circumferential grooves 220 extending around its outer surface. The annular flanges 208 and 216 of the two connector elements 202, 204 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 5 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 10 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 LO 15 pin engaging one of the adjustment holes AH (see Figure 1) in the walking aid. CXI 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 CO recesses 208a, 216a would be shaped accordingly. 20 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 25 be cut into two lengths using conventional cutting tools. The spigot portion 206 of connector element 202 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 208. The spigot portion 214 of the connector element 204 is inserted into the other cut end of the tubular metal shaft of the crutch so that the cut end 30 abuts against the flange 216. Each of the spigot portions 206, 214 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 30 12 25 adhesive or an epoxy adhesive can be coated onto the outer surfaces of the spigot portions 206, 214 so that the adhesive fills the circumferential grooves 212, 220, 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 5 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 206 and 214 and fasteners such as threaded rivets driven into the hole. Once the spigot portions of the connector elements 202 and 204 have been 10 securely fastened inside the cut ends of the tubular metal shaft of the crutch, they can be screwed together as shown in Figure 1 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 15 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 218 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. 20 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

1. 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 for5 securing inside an open end of one of the two tubular shaft portions; oneconnector element having a threaded shank that engages a female thread on the other connector element thereby to provide a means of enabling the connector elements to be releasably fastened together; wherein the two connector elements each have formations that can be brought into10 alignment when the connector elements are screwed together, and whereina locking element is provided that can engage the said formations to prevent relative rotation of the two connector elements.

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 15 formed from a metal.

4. A walking aid according to any one of claims 1 to 3 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 the20 connector further comprises a locking element insertable into the channelto prevent relative rotation of the two connector elements.

5. A walking aid according to any one of claims 1 to 4 wherein the locking element is provided with releasable means for holding it in place in the channel, the releasable means taking the form of a resilient element which25 forms part of or engages the locking element so that the locking element isresiliently biased into the channel.

6. A walking aid according to claim 5 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.

7. 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 6.

8. A method of modifying a walking aid of a type comprising a tubular shaft; 5 which method comprises cutting the tubular shaft into two tubular shaftportions 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 7.30 12 25

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