AU738411B2 - Waterproof cable entry - Google Patents

Description

1W.

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s) ARK ENGINEERING PTY LTD A.C.N. 002 762 487 Invention Title: WATERPROOF CABLE ENTRY The following statement is a full description of this invention, including the best method of performing it known to me/us: -2- WATERPROOF CABLE ENTRY TECHNICAL FIELD This invention relates to a waterproof cable entry for a submersible lamp, and has been devised particularly though not solely for use in a submersible tail lamp fitting on a boat trailer or the like.

BACKGROUND ART In the past it has been particularly difficult to provide a completely waterproof submersible lamp which is able to withstand knocks and vibrations in use while being 15 able to maintain waterproof integrity. There are also many situations where it is desirable to provide a waterproof entry for an electrical cable into an apparatus. This problem is particularly manifest in the tail lights of boat trailers but can also be present in other motor vehicle situations and in other locations such as the provision of underwater lights in swimming pools or in areas which are often subjected to high pressure water treatment.

In the past, in some instances, an elastomeric collar or O-ring is provided which forms an interference fit with 25 the outer sheath of the cable to inhibit the influx of water. In other cases, the cable passes through a bush or collar and is "potted" in place using a setting chemical compound such as a silicon based compound or an epoxy resin. Such waterproof entries can work loose over time, particularly in situations subject to high vibration or stress loadings which will then allow the ingress of water into the apparatus. Furthermore if the outer sheath of a multi-conductor electrical cable becomes ruptured or pierced, water can enter into the housing through the cable sheath, even if the entry point remains intact about the external perimeter of the sheath.

J:\Speci\300 399\350 399\35107.doc -3- DISCLOSURE OF THE INVENTION The present invention therefore provides a waterproof entry for a multi-conductor cable, the entry including: (a) a housing being adapted to receive the cable therethrough; an elastomeric plug able to fit within the housing, the plug having a hole being adapted to receive a conductor of the cable therethrough; a securing cap including an internal bearing surface being configured to abut the plug, wherein, upon rotation of the securing cap, the internal bearing surface rotates against the plug to compress the plug as the plug is urged into and secured within the housing to provide a waterproof seal between the plug and the conductor and between the plug and the housing.

Preferably the housing is cylindrical and axially 15 tapered. Preferably the plug is shaped complimentary to the internal surface of the housing causing the plug to be i compressed as it is urged into the housing. Most preferably the plug has a substantially circular crosssection.

20 Preferably the cap is adapted to be threadably engaged with a male thread on the outside of the housing, the cap having a hole therethrough for passage of the cable.

Preferably a plurality of holes pass through the plug, one hole for each conductor of the cable.

25 Also disclosed herein is a submersible lamp comprising a base member having a waterproof cable entry therethrough, at least one bulb holder mounted to the base member, a lamp S cover positioned over the bulb holder, and a transparent over cover extending over the lamp cover and engageable S 30 with the base member in a sealing relationship so that the base member, waterproof cable entry and over cover together form a waterproof enclosure.

The lamp cover can be mounted directly or indirectly to the base member.

The transparent over cover can be engaged with the 399\35107.doc -4- The transparent over cover can be engaged with the base member in a sealing relationship by the provision of an elastomeric sealing member between the over cover and the base member.

The over cover can have a peripheral flange adapted to mate with a corresponding area on the base member, and the elastomeric sealing member comprises an O-ring or the like located in a suitable groove in one of the base member or the peripheral flange on the over cover.

The transparent over cover can be detachably engageable with the base member by way of fastening members such as bolts or screws passing through the peripheral flange in the over cover and through the base member, outside the location of the elastomeric sealing member.

15 The lamp cover can incorporate portions of different colours suitable for use as a combined tail indicator light 1 on a motor vehicle, such portions typically including a red portion for use as a tail/brake light, and an amber portion for use as an indicator light. Individual bulb holders can be provided for each desired function.

BRIEF DESCRIPTION OF DRAWINGS Notwithstanding any other forms that may fall within 25 its scope, one preferred form of the invention will now be described by way of example only with reference to the accompanying drawings, in which:- Fig. 5 is an exploded cross-sectional elevation to an enlarged scale of a waterproof cable entry; Fig. 6 is a similar cross-sectional elevation showing the cable entry assembled with a cable passing therethrough; and Fig. 7 is a cross-sectional view on the line III-III of Fig. 6.

J:\Speci\300 399\350 399\35107.doc Fig. 1 is a perspective view of a submersible lamp in the form of a combined brake and indicator light for the rear of a motor vehicle.

Fig. 2 is an exploded view of the lamp shown in Fig.

1i, showing the transparent over cover removed.

Fig. 3 is a rear view of the lamp shown in Figures 1 and 2.

Fig. 4 is an underside view of the lamp.

MODES FOR CARRYING OUT THE INVENTION Referring to the drawings a waterproof rear light for a motor vehicle such as a boat trailer will now be described, although it will be appreciated that the 15 invention can be applied to other forms of lamps such as submerged pool lights or lights used in other submerged situations or areas which are exposed to water.

The submersible boat trailer lamp 20 comprises a base member 21 having a waterproof cable entry 22 therethrough (Fig. 3) and a lamp cover 23 mounted to the base member, for example by way of mounting clips 24.

The lamp is provided with one or more bulb holders (Fig.4) in which are mounted light bulbs 26 positioned for appropriate use of the lamp.

25 By way of example only, where the lamp is used as the rear tail light on a motor vehicle such as a boat trailer, the lamp cover may incorporate a red lens portion 27 for the brake/tail light of the motor vehicle, an amber lens portion 28 for the indicator light portion and a clear lens portion 29 in the underside of the lamp cover (as it is seen in Figures 1 and 2) for use in illuminating an adjacent number plate. Where desired, a reflectorised portion 30 may conveniently be provided between the red and amber lenses 27 and 28 which may in turn be provided with suitable focusing or "fresnel" lens configurations as shown in Figures 1 and 2.

J:\Speci\300 399\350 399\35107.doc -6- The submersible lamp is further provided with a transparent over cover 31 which is typically moulded from a high impact resisting plastics material and which is sized and shaped to fit neatly over the lamp cover 23.

The over cover is provided with a peripheral flange 32 arranged to mate with a corresponding surface 33 on the base member 21. The over cover is held in place on the base member by suitable bolts or screws (not shown) passing through holes 34 in the transparent over cover and through corresponding holes 35 in the base member. The over cover forms a waterproof enclosure in combination with the base member by way of sealing means in the form of an elastomeric sealing member between the transparent over cover 31 and the base member 21. The elastomeric sealing 15 member is in the form of an O-ring 36 located within a groove in the face 33 of the base member 21 in a position adjacent the base of the lamp cover 23.

When the transparent over cover 31 is assembled over •the lamp cover 23 onto the base member 21, the peripheral flange 32 seats on the O-ring 36 and forms a completely water tight seal once the screws or bolts are engaged ***through the holes 34 and The submersible lamp is further provided with a waterproof cable entry 22 typically located in the centre 25 of the base member 21, which forms the basis of the invention and which will now be described in more detail.

In the preferred form of the invention cable entry is provided for the housing of a submersible trailer light on a boat trailer is shown with provision made for passing four electrical conductors through the entry into the body of the waterproof light. It will be appreciated that the cable entry can be adapted to other situations and used with other numbers of individual conductors.

When used for a submersible trailer light, the lamp will typically incorporate individual bulbs for a brake light, flashing turn indicator light, and a number plate J:\Speci\300 399\350 399\35107.doc -7conductors.

The cable entry typically takes place through an aperture 1 in the wall 2 of a housing such as the back plate for a submersible trailer light. The housing is typically moulded from a plastics material but may of course be formed in any other manner from any suitable material.

The cable entry comprises a housing 3 through which the cable passes and which typically is cylindrical in form and provided with an external (male) thread 4.

An elastomeric plug 5 is provided formed from rubber or synthetic rubber, or any other suitable elastomeric material and has the general configuration of a cork with a circular cross-section and a tapered cylindrical surface 6 which flares outwardly from a smaller diameter end 7 to a larger diameter end 8. The end 7 is sized to be readily inserted within the bore 9 of the housing 3 and the taper designed to compress the plug as it is urged or forced into the housing.

S 20 To this end the same effect may be achieved by 0e .providing a parallel sided plug and a taper to the bore 9, or alternatively corresponding tapers on both the plug o• and the bore 9 as shown in Figs. 5 and 6.

~The plug is provided with a plurality of parallel 25 holes 10 passing through the plug from one end 7 to the other end 8. The number of holes correspond to the number of conductors in the cable desired to be used with the waterproof cable entry.

The entry further comprises securing means in the form of a cap 11 which has a top 12 with a hole 13 therethrough sized for passage of the cable, and a skirt 14 incorporating an internal or female thread 15 sized and configured to mate with the male thread 4 on the cylindrical housing 3.

35 The larger diameter end 8 of the plug 5 is sized to Td fit within the cap 11.

\.\GHSYDNT2\users\Speci\300 399\350 399\35107A.doc -8- In use, each individually insulated conductor of a multi-strand cable is threaded through one of the holes in the plug 5 until all of the conductors are threaded through the corresponding holes. The cap 11 is also threaded over the cable by passing the cable through aperture 13.

The plug 5 containing the conductors is then inserted into the bore 9 of housing 3 and the cap 11 engaged with thread 4. As the cap is rotated and threaded onto the housing, it forces or urges the plug 5 into the bore 9, compressing the plug and squeezing the elastomeric material of the plug tightly around each individual conductor 16 as shown in Fig. 6. Once so. engaged, there is a waterproof seal provided between each conductor of the cable and the elastomeric plug 5, and between the cylindrical face 6 of the plug 5 and the bore 9 of the housing 3.

In this manner a waterproof cable entry is provided which is simple and quick to install and which results in a secure waterproof entry that, is not prone to deterioration o or leaking through degradation from vibration or other 00 :r causes. Furthermore, because. each conductor is individually sealed within the plug 5, the integrity of the waterproof entry is maintained even if the cable sheath 17 oo:o should be ruptured or pierced allowing water to enter the 900: 25 sheath.

The cable entry can be disassembled at any time and reassembled without losing the viability of the waterproof seal or requiring factory conditions to reinstate the seal.

S The submersible lamp also has the advantage of S 30 simplicity in manufacture and assembly while providing a completely waterproof enclosure which can withstand vibration and hard knocks while maintaining its waterproof integrity. Because the transparent over cover is provided as a separate member from the lamp cover, the lamp cover 3- mY xybe optimised for its desired use. For example, when ul d as the tail light on a motor vehicle, portions of the /01"d \\GHSYDNT2\users\Speci\300 399\350 399\35107A.doc -9may be optimised for its desired use. For example, when used as the tail light on a motor vehicle, portions of the lamp cover may be provided with the desired "fresnel" lens configurations and different colours may be used in different parts of the lamp cover without concern for waterproof integrity of the lamp cover itself.

a e *a J:\Speci\300 399\350 399\35107.doc

Claims (7)

1. A waterproof entry for a multi-conductor cable, the entry including: a housing being adapted to receive the cable therethrough; an elastomeric plug able to fit within the housing, the plug having a hole being adapted to receive a conductor of the cable therethrough; a securing cap including an internal bearing surface being configured to abut the plug; wherein, upon rotation of the securing cap, the internal bearing surface rotates against the plug to 15 compress the plug as the plug is urged into and secured within the housing to provide a waterproof seal between the plug and the conductor and between the plug and the housing.

2. A waterproof entry as claimed in claim 1 wherein 20 the housing is cylindrical and axially tapered.

3. A waterproof entry as claimed in claim 1 or claim 2 wherein the plug is shaped complimentary to the internal surface of the housing causing the plug to be compressed as S* S: it is urged into the housing. *o 25

4. A waterproof entry as claimed in any one of S claims 1 to 3 wherein the plug has a substantially circular cross-section.

5. A waterproof entry as claimed in any one of claims 1 to 4 wherein the cap is adapted to be threadably 30 engaged with a male thread on the outside of the housing, the cap having a hole therethrough for passage of the cable.

6. A waterproof entry as claimed in any one of the preceding claims wherein a plurality of holes pass through 35 the plug, one hole for each conductor of the cable. o* .0.0 i c 3: 399\350 399\35107.doc 441 *g o0* 0, o -11-

7. A waterproof entry f or a multi-conductor cable substantially as described herewith with reference to the accompanying drawings. Dated this 22nd day of June 2001 ARK ENGINEERING PTY LTD By their Patent Attorneys GRIFFITH HACK 00 .0.0S to S. be::. 060* 00.. too: too: 5555 55*55 -555 S.. S. 5. 0 55 too .55 too 5: o: toSS 55 j jSc.30* 3P9\350 399\35107.doc