Fastening Device

Abstract

Herein is described a n electrical earthing device formed from a sheet of material and comprising: an earthing device connector portion, for connection of the earthing device to a component to be earthed; and an earth cable connector portion, for connection to an earth cable. A first part of the earth cable connector portion is disposed in relation to a second part of the earth cable connector portion so as to define a clamping mechanism. In use, an earth cable positioned between the first and second parts is retained in position and maintained in electrical contact with the clamping mechanism by resilient biasing between the first and second parts of the clamping mechanism.

Claims

1. An electrical earthing device formed from a sheet material, comprising: an earthing device connector portion, for connection of the electrical earthing device to a component to be earthed; and an earth cable connector portion, for connection to an earth cable; wherein a first part of the earth cable connector portion is disposed in relation to a second part of the earth cable connector portion so as to define a clamping mechanism; and wherein the first and second parts are resiliently deformable in relation to one another for said earth cable to be positioned therebetween; and wherein, when in use, the earth cable positioned between the first and second parts is retained in position and maintained in electrical contact with the clamping mechanism by resilient biasing between the first and second parts of the clamping mechanism.

2. An electrical earthing device according to claim 1, wherein the electrical earthing device is formed from a single sheet of material.

3. An electrical earthing device according to claim 1, wherein component to be earthed is a cable gland.

4. An electrical earthing device according to claim 3, wherein the cable gland comprises a male threaded fastener and corresponding female threaded fastener.

5. An electrical earthing device according to claim 1, wherein the earthing device connector portion is shaped to fit onto a cable gland.

6. An electrical earthing device according to claim 3, wherein the earthing device connector portion is for encircling, at least in part, the male threaded fastener of the cable gland.

7. An electrical earthing device according to claim 1, wherein the earth cable connector portion comprises at least one bend.

8. An electrical earthing device according to claim 1, wherein at least one of the first and second parts are toward the distal end of the earth cable connector portion.

9. (canceled)

10. An electrical earthing device according to claim 1, wherein the earth cable connector portion comprises an earth cable aperture.

11. An electrical earthing device according to claim 1, wherein the first part of the earth cable connector portion comprises a slot to allow at least a portion of second part of the earth cable connector portion to pass therethrough.

12. An electrical earthing device according to claim 1, wherein at least one of the first and second parts of the clamping mechanism comprises at least one grip element.

13. An electrical earthing device according to claim 1, wherein the device is of unitary construction.

14. A method, comprising the steps of: providing an electrical earthing device formed from a sheet material having an earthing device connector portion, for connection of the electrical earthing device to a component to be earthed; and an earth cable connector portion, for connection to an earth cable; wherein a first part of the earth cable connector portion is disposed in relation to a second part of the earth cable connector portion so as to define a clamping mechanism; and wherein the first and second parts are resiliently deformable in relation to one another for said earth cable to be positioned therebetween; and wherein, when in use, the earth cable positioned between the first and second parts is retained in position and maintained in electrical contact with the clamping mechanism by resilient biasing between the first and second parts of the clamping mechanism; securing the electrical earthing device to the earth cable; and securing the earth cable to the electrical earthing device, by resiliently deforming the clamping mechanism and inserting the cable between the first and second parts of the earth cable connector portion.

15. A method according to claim 14, wherein the component to be earthed is a cable gland having a male threaded fastener and a corresponding female threaded fastener.

16. A method according to claim 15, wherein the electrical earthing device is secured to the cable gland by inserting the electrical earthing device between the male threaded fastener and the corresponding female threaded fastener.

17. A method, comprising the steps of: providing a sheet material; conducting one or more steps of one or more of a bending, a roll forming, a stamping and a pressing of the sheet material to form an electrical earthing device; and producing from said sheet material an electrical earthing device formed from a sheet material having an earthing device connector portion, for connection of the electrical earthing device to a component to be earthed; and an earth cable connector portion, for connection to an earth cable; wherein a first part of the earth cable connector portion is disposed in relation to a second part of the earth cable connector portion so as to define a clamping mechanism; and wherein the first and second parts are resiliently deformable in relation to one another for said earth cable to be positioned therebetween; and wherein, when in use, the earth cable positioned between the first and second parts is retained in position and maintained in electrical contact with the clamping mechanism by resilient biasing between the first and second parts of the clamping mechanism.

18. The method according to claim 17, further comprising the step of: creating an outline of a device pattern on a sheet of material; and subsequently conducting one or more steps of one or more of bending, roll forming, stamping and pressing the sheet material to form said electrical earthing device.

19. The method according to claim 18, wherein the step of creating the outline comprises machining or stamping.

20. The method according to claim 18, further comprising the step of: creating a plurality of electrical earthing devices from a single sheet of material.

21. The method according to claim 20, further comprising the step of: creating an outline of the plurality of said electrical earthing devices, by stamping or machining blanks from a single sheet of material and then conducting the one or more steps of one or more of bending, roll forming, stamping and pressing the sheet material to form each said electrical earthing device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Non-limiting example embodiments the present invention will now be described with reference to the accompanying drawings in which:

[0061] FIG. 1 shows a device according to an embodiment of the present invention, located inside a cable housing connected to a cable gland;

[0062] FIG. 2 shows an embodiment of the present invention connected to a cable gland;

[0063] FIGS. 3 and 4 show two views of an embodiment of the present invention connected to an earth cable;

[0064] FIGS. 5 and 6 show two views of another embodiment of the present invention, wherein the embodiment comprises at least one grip element;

[0065] FIG. 7 shows a view of the top of the device shown in FIGS. 5 and 6;

[0066] FIG. 8 shows another embodiment of the present invention, located inside a cable housing and connected to a cable gland;

[0067] FIGS. 9 to 11 show simplified embodiments according to the present invention, showing various arrangements of the earth cable connector portion; and

[0068] FIG. 12 shows another embodiment of the present invention, wherein the device comprises an adjustment feature;

[0069] FIG. 13 shows another embodiment of the present invention, only showing the earth cable connector portion;

[0070] FIG. 14 shows an embodiment of the present invention according to FIG. 13, further showing the earthing device connector portion.

DETAILED DESCRIPTION

[0071] FIG. 1 shows a device 100 according to an embodiment of the present invention. The device 100 is located inside a cable housing 003. The cable housing has a cable gland 004 which terminates in the housing. Housings such as housing 003 shown in FIG. 1 are typically made from an insulating material such as a plastics material. Cable glands which may have steel wire armour (SWA) around them terminate in such housings, and require to be earthed, usually via an earth cable 002, as discussed below.

[0072] As shown in FIGS. 1 and 2, the device 100 comprises an earthing device connector portion 102 for connecting the electrical earthing device 100 to the component to be earthed 002. In FIGS. 1 and 2, the component to be earthed 001 is a cable gland 004 which is coupled in use to the steel armour of an armoured cable. The invention should not be construed as being limited to electrical earthing of such cable glands, and can be applied to other types of electrical cable and/or other components, fixtures or fittings.

[0073] The cable gland 004 is made from an electrically conductive material, such as copper, to provide electrical connection to the SWA (not shown). Therefore, if the device 100 is connected to the cable gland 004, then there will be an electrical connection established between the SWA, the gland 004 and the device 100.

[0074] The device 100 further comprises an earth cable connector portion 104, which is for connecting to an earth cable 002. As easily seen in FIG. 2, the earth cable connector portion 104 comprises a first part 106 and a second part 108, which are disposed so as to define a clamping mechanism. The clamping mechanism is suited to retain an inserted earth cable 002, ensuring constant electrical connection between the earth cable 002 and the device 100. The labeling in the figures of the first part 106 and the second part 108 should not be construed to be limiting, as the portion currently labeled the first part 106 may easily be labeled the second part 108, and vice versa.

[0075] The first and second parts 106/108 are resiliently deformable in relation to one another, to allow the earth cable 002 to be positioned therebetween. The first and second parts 106/108 may be deformed by using a screwdriver, by hand, or by the earth cable 002 itself. To release the earth cable 002, the clamping mechanism may be opened by moving the first and second parts 106/108 away from one another. This may be done by using a tool, or by hand. When the earth cable 002 is positioned between the first part 106 and the second part 108, the clamping mechanism retains by resilient biasing and maintains the earth cable 002 in mechanical and electrical contact with the device 100. The biasing force keeping the earth cable 002 in place will depend upon the application and the thickness of the earth cable.

[0076] As shown in the figures, the earthing device connector portion 102 and the earth device connector portion 104 are electrically and mechanically connected together. The device 100 in the figures is also made from a single material (such as those described in the summary section) and is of unitary construction (i.e. formed from a single piece of the material). This enables the device 100 to be more easily manufactured than multi-component devices. In alternative embodiments (not shown), the earthing device is formed from multiple parts, however, which may be welded, pressed, bolted, riveted or otherwise coupled together.

[0077] The cable gland 004 as shown in FIGS. 1 and 2 comprises a male threaded fastener 006 and a female threaded fastener 008. In this particular embodiment, the male threaded fastener 006 is a bolt and the female threaded fastener 008 is a nut. In a typical installment process, the gland 004 would be inserted into the housing via the male threaded fastener 006. The device 100 would then be connected to the cable gland 004 via the earthing device connector portion 102. The female threaded fastener 008 would then be threaded onto the male threaded fastener 006, thus securing the cable gland 004 to the housing and the device 100 to the cable gland. After this, the earth cable 002 would be placed between the clamping mechanism of the device (between the first and second parts 106/108 of the earth cable connector portion 104). The earth cable 002 may need to be stripped of any insulation before inserting into the clamping mechanism of the device 100, to ensure electrical contact. Alternatively, the first and second parts 106/108 may be sharp enough to pierce through the insulation on the earth cable 002, removing the necessity of stripping the insulation.

[0078] As shown in FIGS. 3 and 4, the earthing device connector portion 102 may be shaped to encircle the male threaded fastener 006 of the cable gland. As may be easily envisaged, the earthing device connector portion 102 may only partly encircle the male threaded component of the cable gland 006. The earthing device connector portion 102 shown in FIGS. 1 to 4 functions as a washer. Alternatively, the earthing device connector portion 102 may clip onto the component to be earthed 001.

[0079] FIGS. 5 to 7 show various views of the device 100 according to the present invention. The device 100 further comprises a grip element 120 as seen in FIG. 5 and a grip element 121 as seen in FIG. 6. The grip elements 120,121 may be used in combination with any other embodiment disclosed herein.

[0080] As best seen in FIG. 5, the grip elements 120 may be located on the first part 106 of the earth cable connector portion. The grip elements 120 as shown are slots, which provide a high friction surface to retain the earth cable 002. The slots should not be viewed as being limiting, as there may be any type of geometry used to increase the friction on the earth cable when in use.

[0081] As seen in FIG. 6, the grip elements 121 may also be on the second part 108 of the earth cable connector portion. The grip elements 121 as shown here are a serrated edge. The serrations may be stamped, pressed, or cut. There may be any other type of grip element 121 used to increase the friction of the clamping mechanism in use. Again, the grip element 121 as shown may pierce the insulation of the earth cable 002 which is to be inserted. The grip element 121 may be located on any edge to provide increased friction.

[0082] The grip element 121 may also be located on a bend, and at the proximal or distal ends 124/126 of the earth cable connector portion.

[0083] An earth cable aperture 114 can also be seen in FIGS. 5 to 8. In FIG. 8, the earth cable 002 can clearly be seen to go through the earth cable aperture 114. There may be more than one earth cable aperture 114 if the geometry of the device requires it.

[0084] FIGS. 9 to 11 show further embodiments of an earthing device 100, showing various arrangements of the earth cable connector portion 104. The earth cable connector portion 104 may comprise a bend 110, or a plurality of bends 110. There may be one continuous bend, wherein the bend creates the first part 106 and the second part 108 of the earth cable connector portion 102. The bends 110 may provide the spring force required to create the clamping mechanism. The material which the device 100 is made from may also provide the spring force required.

[0085] In FIGS. 9 to 11, the second part 108 of the earth cable connector portion 104 is toward the distal end 126 of the earth cable connector portion 104. The distal end 126 is defined as being the end furthest from the earthing device connector portion 104. The proximal end 124 is shown joined to the earthing device connector portion. The second part 108 may form the end of the earth cable connector portion 104 in one section, as in FIG. 10, or in a plurality of sections, such as in FIGS. 9 and 11. The features on the second part 108 in FIGS. 9 and 11 may provide more friction when gripping the earth cable 002, than other embodiments.

[0086] An intermediate part 112 can be seen in FIGS. 9 and 10, which connects the first and second parts 106/108. The intermediate part 112 may serve as a bridge to adjust the geometry of the clamping mechanism, to suit a different range of earth cables for example. The intermediate part 112 may also be used to alter the geometry of the device 100 so that it fits in a special application, such as a specific junction box.

[0087] FIG. 12 shows another embodiment of the present invention, wherein the device 100 comprises an adjustment feature 116. The adjustment feature 116 as shown comprises an adjustor 118, used to adjust the biasing force of the clamping mechanism. In the embodiment shown, the adjustor 118 is a grub screw, which is threaded into the adjustment feature 116. Alternative adjustors, such as a nut and bolt combination may also be used. The adjustor 118 may be used to increase the pressure exerted onto the earth cable 002 by the clamping mechanism. The adjustor 118 provides the clamping mechanism additional pull resistance, as required for some applications of the device 100, preventing the earth cable 002 from working loose and out of the device 100. As should be easily envisaged, the adjustor 118 may be in a different location to that shown in FIG. 12, whilst still serving its purpose.

[0088] FIGS. 13 and 14 show another embodiment of the present invention. The device 100 comprises an earthing device connector portion 102 (FIG. 14), and an earth cable connector portion 104. The earth cable connector portion 102 comprises a first part 106, a second part 108, and an intermediate part 112. The first part 106 comprises a slot 122 which is shaped to allow at least a portion of second part 108 of the earth cable connector portion to pass through it. The second part 108 comprises an earth cable aperture 114.

[0089] When manufactured, the earth cable connector portion 104 is shaped as shown in FIG. 13. The first and second portions 106/108 define the clamping mechanism and are resiliently deformable in relation to one another. To connect an earth cable 002 to the device 100, the second part must first be passed through the slot 122 in the first part 106 and held in place (as in FIG. 14). When the second part 108 is moved into the position shown in FIG. 14, there is a retarding force which seeks to return the second part 108 to its original position as shown in FIG. 13. The earth cable 002 is then inserted into the earth cable aperture 114. When the second part 108 is released, it traps the earth cable 002 between the slot 122 and the first part 106. To permit removal of the earth cable 002 from the device 100, the tension on the clamping mechanism is released by moving part 108 further through the slot 122.

[0090] The slot 122 as shown is rectangular in shape, however this should not be construed to be limiting, as the slot 122 may be any suitable shape to enable the clamping mechanism to function as described. The slot 122 may also extend to one edge of the first part 106, thereby creating a channel for the second part 108 to be placed into.

[0091] Whilst specific embodiments of the present invention have been described above, it will be appreciated that departures from the described embodiments may still fall within the scope of the present invention.