Device for Fixing an Electrical Connection Terminal to a Support

Abstract

A device for fixing an electrical connection terminal to a support provided with an opening, the device comprising: a generally tubular bush for location within the opening of the support and provided with opposed front and rear ends between which extends a bore; a dowel configured for forced insertion into the bore so as to cause outward deformation of the bush, the dowel being provided with connection means engageable with a connector for fastening the terminal to the support and to facilitate the forced insertion; wherein there is further provided a weak region interconnecting the bush and the dowel.

Claims

1. A device for fixing an electrical connection terminal to a support provided with an opening, the device comprising: a generally tubular bush for location within the opening of the support and including a front end , an opposed rear end, and partially defining an axial through bore; a dowel configured for forced insertion into the bore so as to cause outward deformation of the bush, the dowel including a connection means engageable with one of a connector for fastening the terminal to the support and a tool for forced insertion of the dowel into the bush; and a weak region interconnecting the bush and the dowel.

2. A device as claimed in claim 1, wherein the weak region is configured to break upon forced insertion of the dowel into the bush.

3. A device as claimed in claim 1, wherein the weak region interconnects the rear face of the bush and the front end of the dowel.

4. A device as claimed in claim 1, wherein the weak region extends at least substantially around the periphery of the device.

5. A device as claimed in claim 1 and made from aluminium, copper, titanium, stainless steel or brass.

6. A device as claimed in claim 1, and further including a coating to resist corrosion.

7. A device as claimed in claim 1, wherein the dowel further includes a rib, and when the dowel is fully inserted in the bush, then the rib is configured to conceal a portion of the weak region remaining on the bushrear end.

8. A device as claimed in claim 1, wherein the bore is substantially cylindrical.

9. A device as claimed in claim 1, wherein the bore narrows towards the front end of the bush.

10. A device as claimed in claim 1 wherein a portion of the dowel configured for forced insertion into the bore is substantially cylindrical.

11. A device as claimed claim 1, wherein a portion of the dowel configured for forced insertion into the bore narrows towards the front end of the dowel.

12. A device as claimed in claim 1, wherein a cross section of the dowel is larger than a cross-section of the bore at corresponding points along their axial lengths so as to cause radially outward deformation of the bush upon forced insertion of the dowel.

13. A device as claimed in claim 1, wherein the bush and the dowel are unitary.

14. A device as claimed in claim 1, wherein the connection means is comprised of a threaded hole partially defined in the dowel and open at a first end.

15. A method of installing a fixing device on a substrate provided with an opening, the method comprising the steps of: providing a fixing device comprising: a bush with a bore, a dowel and a weak region interconnecting the bush and the dowel; mounting the fixing device to the substrate such that the bush locates in the opening in said substrate; applying a force to the dowel in a direction towards the bush so as to cause the weak region to break; and continuing to apply the force to the dowel so as to cause forced insertion of the dowel into the bore and cause outward deformation of the bush.

16. A method as claimed in claim 14, and further comprising the steps of: furnishing the dowel with a rib; and continuing to apply the force to the dowel to cause the rib to abut the bush and to conceal a portion of the bush exposed following the breaking of the weak region.

17. A grounding fixture for fixing an electrical terminal to workpiece defining a bore, the grounding fixture arranged for installation into the bore with a tool, and the grounding fixture comprising: a tubular bush including a first end, an opposed second end, and partially defining an axial through bore; a dowel engageable with the tool; a frangible connection between the bush second end and the dowel; and the grounding fixture is operable by the tool for movement between a pre-installed condition, wherein the frangible connection is intact and holds the dowel at the second end of the bush, and an assembled condition, wherein the frangible connection is broken and the dowel is forced into the bore of the bush.

18. A grounding fixture according to claim 17 wherein: the dowel includes a threaded axial hole engageable by the tool to force the dowel axially into the bore of the bush; and the frangible connection holds the dowel hole coaxial to the bush bore at the bush second end when the grounding fixture is an the pre-installed condition.

19. A grounding fixture according to claim 18, wherein the electrical terminal is securable to the grounding fixture with a threaded fastener, and the threaded hole of the dowel is engageable by the threaded fastener.

20. A grounding fixture according to claim 17 wherein an outer dimension of the dowel is larger than an inner dimension of the bush bore, and in the pre-installed condition a portion of the bush has a first outer radius and in the assembled condition the portion of the bush has a second outer radius greater than the first outer radius, and the bush is securable to the workpiece at least in part by the radial expansion of the bush.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] By way of example only, one specific embodiment of the present invention will now be described in detail, with reference being made to the accompanying drawings, in which:

[0028] FIG. 1 is a rear perspective view of the fixing device according to the invention;

[0029] FIG. 2 is a cross-sectional view from the fixing device shown in FIG. 1;

[0030] FIG. 3 is an exploded cross-sectional view of the weak region of the fixing device shown in FIG. 2.

[0031] FIGS. 4a to 4c show three stages of the process of installing the fixing device of FIGS. 1 to 3 into a substrate;

[0032] FIG. 5 shows the fixing device fitted to the substrate; and

[0033] FIG. 6 shows the electrical terminal secured to the fixing device by a screw.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Referring initially to FIGS. 1 to 3, there is provided a fixing device, generally indicated 10, suitable for securing an electrical terminal 100 (FIGS. 5 and 6) to a substrate 110 (FIGS. 5 and 6) provided on an aircraft, a railway line and so on. The fixing device comprises a bush 20, a dowel 50 and a weak region 70 interconnecting the bush 20 and the dowel 50. The fixing device may be cast, machined or cold formed as a unitary item from aluminum, copper, stainless steel or titanium and finally machine finished to a high standard before possibly being provided with a coating.

[0035] The bush 20 has a cylindrical body 22 defining front and rear ends 24,26 and a bore 28 extending axially therethrough. The cylindrical body 22 is intended for location in an opening 112 in the substrate 110 and is sized to engage closely the portion of the substrate inside the opening 112, such that electrical energy may be conducted between the bush 20 and the substrate 110.

[0036] The bush 20 also includes a plate 30 provided on the front end 24 of the cylindrical body 22 and is sized to extend radially someway therebeyond. The plate 30 has a generally planar rear face 36 and a generally planar front face 38 to which the terminal 100 can be secured. An aperture 40 is formed in the centre of the plate 30 for allowing the passage of a screw 114, bolt or other mechanical fastener to be discussed below in connection with FIGS. 5 and 6. The plate 30 may include a lip 32 extending rearwardly from its periphery to define a rearward facing annular contact face 34.

[0037] The dowel 50 includes a generally cylindrical front portion 52, a generally cylindrical rear portion 54 and a circumferential abutment 56 therebetween. The dowel 50 has a generally circular front face 58 defined by the front portion 52, a generally circular rear face 60 defined by the rear portion 54 and a hole 62 extending between those front and rear faces 58,60. The hole 62 is slightly diametrically smaller than the aperture 40 and is threaded to engage the screw 114. The front portion 52 has a length substantially equal to the length of the bore 28 and a diameter generally greater than the diameter of the bore 28, except for a narrow portion 64 adjacent the front face 58 which tapers inwardly. The abutment 56 is diametrically larger than the front portion 52 and defines a forward facing inclined face 66.

[0038] As best shown in FIG. 3, the weak region 70 is a thin band of material interconnecting the bush 20 and the dowel 50. The weak region 70 is defined by an internal radius 72 between the front face 58 of the dowel 50 and the bore 28 of the bush 20. In addition, the weak region 70 is defined by the vertex 74 between the narrow band 64 and the end face of the cylindrical body 22 which are arranged at an acute angle.

[0039] Installation of the fixing device 10 is illustrated in FIGS. 4a to 4c. FIG. 4a shows the fixing device located in the opening 112 formed in the substrate 110 and achieves two points of contact between the fixing device and the substrate. The first point of contact and possibly the most reliable is between the cylindrical body 22 of the bush 20 and the portion of the substrate 110 inside the opening 112. The second point of contact and possibly the least reliable (at least with a coated substrate) is between the annular contact face 34 of the bush 20 and the front face 116 of the substrate 110.

[0040] A setting tool 130 is employed to install the fixing device on the substrate 110. The setting tool 130 has a cylinder 132 which bears against the front face 38 of the plate 30 to urge the bush 20 towards the substrate 110. The setting tool 130 also has a rotatable piston 134 provided with a threaded shank 136 adapted to extend through the aperture 40 and threadingly to engage the hole 62.

[0041] Turning now to FIG. 4b, the piston has been partially retracted within the cylinder so as to apply a tensile force to the dowel 50 in a forward direction while restricting movement of the bush 20. This tensile force causes the weak region to break as the front portion 52 of the dowel 50 begins to move into the bore 28. Movement of the dowel 50 into the bore 28 is assisted initially by the narrow portion 64 adjacent the front face 58 which tapers inwardly. The narrow portion may indeed act as a cam surface to cause outward deformation of the cylindrical body 22. The outwardly deformed portion 68 of the cylindrical body 22 bears against the rear face 118 of the substrate 110 and thus restricts forward movement of the fixing device 10 relative to the substrate 110.

[0042] FIG. 4c shows the final step of the installation process in which the piston 134 is further retracted in the cylinder 130 so as to cause the front portion 52 of the dowel 50 to locate fully within the bore 28 of the cylindrical body 22. In this position, further deformation of the cylindrical body 22 has occurred so as to achieve greater contact with the rear face 118 of the substrate 110. Upon breaking the weak region 70, uncoated portions of the dowel 50 and the bush 20 appear in the area of the break. The uncoated portion of the dowel 50 locates in the bore 28 and is thus protected adequately from the elements to minimize the chance of corrosion. The uncoated portion of the cylindrical body is shielded by the inclined face 66 of the abutment 56, which abuts the cylindrical body 22 once the dowel 50 fully locates inside the bore 28. In fact, the inter-engagement of the abutment 56 and the cylindrical body 22 may serve as an indication that full insertion of the dowel 50 within the bore 28 has been achieved.

[0043] FIG. 5 shows the fixing device 10 secured to the substrate 110, which is trapped tightly between the lip 32 of the plate 30 and the deformed portion 68 of the cylindrical body 22. In preparation for installation, the terminal 100, the washer 106 and the screw 114 are presented to the fixing device 10. The terminal 100 and the washer 106 each have respective openings 104, 108 corresponding to opening 112 for allowing the passage of the screw 114.

[0044] FIG. 6 shows the terminal 100 secured to the substrate 110 via the screw 114, washer 106 and the fixing device 10. The inter-engagement of those parts facilitates effective electrical conductivity between the terminal and the substrate.

[0045] It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only, and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention as defined by the appended claims.