AU711925B2 - Submersible lamp - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): ARK ENGINEERING PTY LTD A.C.N. 002 762 487 Invention Title: Submersible Lamp *c 4 4 4 4* *r 4 The following statement is a full description of this invention, including the best method of performing it known to me/us: -2- SUBMERSIBLE LAMP TECHNICAL FIELD This invention relates to a submersible lamp and has been devised particularly thought 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. 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 a trailer light situation the problem is made worse by the necessity to provide different coloured lenses within a single light.

For example, the tail and brake lights of a motor vehicle *0 must have a red lens, the turn indicator light an amber 25 lens and there is also often the necessity to provide a clear lens section for illuminating the adjacent number plate of the trailer or other motor vehicle. It has proven extremely difficult to manufacture conventional combined tail/stop/indicator/number plate lights which will maintain waterproof integrity at the joins of the various different coloured lamp segments. It is of course possible to provide individual lamps for each of the above functions but this significantly increases the cost and also the complexity and "untidiness" on the motor vehicle.

The legal requirements of many countries also make it 5 necessary for the various lenses to have certain light J:\Speci\300 399\300 349\32341.doc -3focusing or diffracting characteristics and it has proven extremely difficult to provide these characteristics in a waterproof tail light or indicator light lens of the type described above.

There are also many situations where it is desirable to provide a waterproof entry for an electrical cable into an apparatus. In the past, in some instances, an elastomeric collar or O-ring is provided which forms an interference fit with 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 15 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 S 20 intact about the external perimeter of the sheath.

el S"DISCLOSURE OF THE INVENTION The present invention therefore provides 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 cover positioned over the bulb holder, and a transparent over cover extending over the lamp cover and engageable with the base member in a sealing relationship so that the base member, waterproof cable entry and over cover together form a waterproof enclosure.

Preferably the lamp cover is mounted directly or indirectly to the base member.

Preferably the transparent over cover is engaged with the base member in a sealing relationship by the provision of an elastomeric sealing member between the over cover and J:\Speci\300 399\300 349\32341.doc -4the base member.

Preferably the over cover has 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.

Preferably the transparent over cover is 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.

In one form of the invention, the lamp cover incorporates portions of different colours suitable for use as a combined tail indicator light on a motor vehicle, such 15 portions typically including a red portion for use as a tail/brake light, and an amber portion for use as an indicator light. In such an embodiment, individual bulb holders are provided for each desired function.

Also disclosed herein is a waterproof entry for a 20 multi-conductor cable, said entry comprising a housing through which the cable passes in use, an elastomeric plug adapted to fit within the housing, securing means adapted CC to urge the plug into the housing and secure the plug within the housing, the housing, plug and securing means 25 being arranged to compress the plug as it is urged into the housing, and a plurality of holes passing through the plug, one hole for each conductor in the cable so that in use the plug may be threaded onto the conductors of the cable and then compressed within the housing, providing a waterproof seal between the plug and each conductor, and between the plug and the housing.

The housing can be cylindrical in configuration and the plug has a substantially circular cross-section.

At least one of the housing or the plug are tapered, causing the plug to be compressed as it is urged into the housing.

J:\Speci\300 399\300 349\32341.doc The securing means can comprise a threaded cap adapted to be engaged with a male thread on the outside of the housing, the cap having a hole therethrough for passage of the cable.

BRIEF DESCRIPTION OF DRAWINGS Notwithstanding any other forms that may fall within 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. 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.

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

i, showing the transparent over cover removed.

a.

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

Fig. 4 is an underside view of the lamp.

20 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 ao 9 therethrough; and Fig. 7 is a cross-sectional view on the line III-III of Fig. 6.

MODES FOR CARRYING OUT THE INVENTION In the preferred form of the invention a waterproof rear light for a motor vehicle such as a boat trailer will now be described, although it will be appreciated that the 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.

J:\Speci\300 399\300 349\32341.doc -6- 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.

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 15 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.

S 20 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 25 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. In the preferred form of the invention the elastomeric sealing 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 J:\Speci\300 399\300 349\32341.doc -7lamp 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 of the base member 21, which will now be described in more detail.

Referring to the drawings a waterproof cable entry is provided for the housing of a submersible trailer light on a boat trailer with provision made for passing four electrical conductors through the entry into the body of 15 the waterproof light. It will be appreciated that the •go• cable entry can be adapted to other situations and used with other numbers of individual conductors.

S"When used for a submersible trailer light, the lamp will typically incorporate individual bulbs for a brake 20 light, flashing turn indicator light, and a number plate illuminating lamp which together with a common return conductor requires the passage of four individual 4. conductors.

The cable entry typically takes place through an 25 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 J:\Speci\300 399\300 349\32341.doc -8which 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.

To this end the same effect may be achieved by providing a parallel sided plug and a taper to the bore 9, or alternatively corresponding tapers on both the plug and the bore 9 as shown in Fig. 1.

The plug is provided with a plurality of parallel 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.

Poo 15 The entry further comprises securing means in the form of a cap 11 which has a top 12 with a hole 13 therethrough be 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 20 cylindrical housing 3.

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

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. 2. Once so engaged, there is a waterproof Rseal provided between each conductor of the cable and the J:\Speci\300 399\300 349\32341.doc -9elastomeric 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 or leaking through degradation from vibration or other causes. Furthermore, because each c.onductor is individually sealed within the plug 5, the integrity of the waterproof entry is maintained even if the cable sheath 17 should be ruptured or pierced allowing water to enter the sheath.

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

15 The submersible lamp also has the advantage of ".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 20 as a separate member from the lamp cover, the lamp cover may 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 25 different parts of the lamp cover without concern for waterproof integrity of the lamp cover itself.

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Claims (2)

1. 4.. *444 *44* 4, S. *5 4 4
2. 9. 9. *4*4 S 9S 4e 4 4 5 S S 4. S THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS 1. 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 cover positioned over the bulb holder, and a transparent over cover extending over the lamp cover and engageable with the base member in a sealing relationship so that the base member, waterproof cable entry and over cover together form a waterproof enclosure. 2. A submersible lamp as claimed in claim 1 wherein the transparent over cover is 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. 3. A submersible lamp as claimed in claim 2 wherein 15 the over cover has 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. 20 4. A submersible lamp as claimed in claim 3 wherein the transparent over cover is 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. A submersible lamp as claimed in any one of the preceding claims wherein the lamp cover incorporates portions of different colours suitable for use as a combined tail indicator light on a motor vehicle. 6. A submersible lamp substantially as described herewith with reference to the accompanying drawings. Dated this 23th day of August 1999 ARK ENGINEERING PTY LTD By their Patent Attorneys GRIFFITH HACK J:\Speci\300 399\300 349\32341.doc