HOLDER ASSEMBLY FOR INCANDESCENT ELECTRIC LAMPS Field of the invention The present invention relates to holder assemblies for lamps, particularly halogen incandescent lamps. More particularly, the present invention relates to novel incandescent lamp and holder assembly, which is simple to assemble and easy to align with respect to the reflector with which, it will generally be used. The present invention particularly relates to a lamp-holder assembly, which is particularly suitable for use in automotive headlights where the position of the filament of the lamp with respect to the focus of the reflector is of utmost importance for the required light distribution emanating from the headlight beam. Apart from the fact that the lamp must be accurately aligned with respect to the focus of the reflector, it s very important that such alignment is retained in spite of the shock and vibration of the vehicle which may be transferred to the lamp. The present invention ideally satisfies these requirements in an improved and hitherto unknown manner.

Background of the invention Lamps, particularly, halogen incandescent lamps are well known in the art. Most known lamps employ glass capsules with at least a filament having lead wires for electrical connections to the filament. The glass capsule may have one end flattened or pinched into a press seal. The glass capsule may be made of high temperature resistant glass such as quartz glass. While, the lamps with a single filament are known two filament lamps for projection of "high beam"and"low beam"are particularly common. It becomes very important in such lamps they do not lose their alignment since misalignment of double filament lamps could throw the two light beams in completely wrong directions causing dangerous situations on the road.

The applicants have made several improvements in the lamp assemblies of the type mentioned above. The applicants'own co-pending application No. 608/Del/99 discloses an improved incandescent lamp assembly, which comprises in combination, a single ended capsule having a press seal thereof One or more filaments are located inside the capsule, and current connection leads extend from the press seal. A cylindrical cup portion with a slit on the top portion thereof for receiving the press seal portion of said capsule is provided. The socket means is closed at one end with an insulated material in which the said electrical connection leads are embedded, the open upper portion of the socket means receiving said cup in a snug yet adjustable manner. The socket has one or more vertical weld means for weldably connecting said socket means to said cup, and one or more horizontal weld means located between said vertical weld means. A pair of connection prongs extend outwardly and downwardly from said insulating material. There is also provided a hollow stepped ring with a stepped annular ring means and a flat collar means, the stepped ring means receiving in its hollow portion, the socket means in a sealed relationship. The said horizontal weld means is weldably sealed on the top surface said stepped annular ring.

In another co-pending application No. 110/Del/00 filed on February 8,2000, the applicants disclose yet another novel lamp and socket assembly. In this embodiment, the hollow ring means has flat portions for receiving the socket means in a sealed relationship.

The hollow ring comprises a hollow stepped ring with a stepped annular ring means and a flat collar means, the stepped ring receiving in its hollow portion the socket means in a sealed relationship. In this embodiment, the horizontal weld means is weldably sealed on the top surface of said stepped annular ring.

In a third co-pending application No. 447/Del/01 filed on 30/3/01 there is disclosed yet another improved version of the lamp and socket assembly which is simpler in construction and easier to assemble as compared to the assemblies disclosed in the applicants co-pending applications referred to above. The invention disclosed by this application is characterised by an adapter means with a stepped up portion to receive the pinched potion of the glass capsule. The adapter consists of flaps to lock on the projections of the flat surfaces of capsule. The adapter is mounted on an adjustment collar.

As in said co-pending applications, in the present invention also, the lamp portion is the conventional capsule type bulb enclosing at least a filament having lead wires for electrical connections and a pinched flattened plate like portion on the other end having projections on both surfaces.

However, despite considerable advancements made in respect of lamp assemblies of the type mentioned above, the problem of accurately aligning the lamp with respect to the focus of the reflector and retaining it there in spite of the shock and vibration of the vehicle which may be transferred to the lamp, continues to exist.

The prior art achieves this object with a special spring means located within the bulb holder which biases against the inside of the neck portion of the reflector thereby holding the holder with the bulb therein rigid in a particular position. Various designs of springs are used to hold tight the halogen bulb in the head light beam to achieve this aim.

In certain halogen lamps such as H8/H9/Hl1 specified in European specification ECE37R, a spring is provided within the holder, a portion of which the spring protrudes outside the neck diameter of the holder. When these bulbs are fitted in the head light beam, i. e the neck portion of the reflector, the three lug like projections on the holder, at the baser of the bulb match the slots provided in the reflector beam. The bulb is inserted in the head light reflector beam through these slots and rotated by which the spring is made to compress centrally inward. In a required position a groove is provided in the beam in which the spring is released radially outward getting locked in the groove and the lamp is pressed by the spring in the Vee support provided in the head lamp beam.

One of the major disadvantage of this kind of design is that due to the specific shape of the spring, the spring portion inside the cap, when compressed moves centrally inward fouling against the space occupied by the pinch portion of the bulb. This may result in the pinch portion obstructing the movement of the spring. In addition, exertion of any force may push the compressed spring inward against the pinch portion of the bulb, which could cause damage to the bulb, spring or both.

Various attempts have been made in the art to obviate this disadvantage. Attempts have been made to develop springs with different materials and with different mechanical strengths but without significant results since the prior art fails to recognise that the problem is not with respect the material of the spring or its mechanical strength but with respect to the very nature of the spring itself.

Objects of the invention It is therefore an object of the present invention to provide an improved holder assembly for halogen lamps which is capable of holding the halogen lamp in the head light beam in a shock proof manner and preventing movement thereof due to the vibration of the automobile.

It is another object of the present invention to provide an improved holder assembly incorporating a novel biasing means which does not foul against the pinch portion of the lamp, yet permits unobstructed movement of the biasing means.

It is yet another object of the present invention to provide a holder with a biasing means, which not only obviates the disadvantages of the prior art but also holds the lamp with significantly higher strength than other prior designs.

These and other objects of the present invention are achieved by the improved holder assembly incorporating a novel biasing mechanism which bases away from the pinched portion of the lamp and yet provides more force to hold the lamp in position.

Summary of the invention Accordingly, the present invention provides an improved holder assembly for holding a bulb in a locked position in the head light beam which comprises a holder, at least one slot within said holder for receiving the pinched portion of the bulb, one or more lugs extending from said holder for mating with corresponding grooves in the head light beam, a biasing means located within the inner diameter of said holder, said biasing means having end portion projecting outwardly of said neck portion from one side of said holder and at least a pair of arms connected within said holder at the opposite side of said holder, said at least one slot for receiving said pinched portion of said bulb lying in a plane inside the arms of said biasing means, each arm of said biasing means having at least a portion lying away from said pinched portion such that when said holder is mounted in the head light beam and rotated to mate said one or more lugs with said grooves in said head light beam, said end portion of said biasing means is depressed, causing said arms to open outwardly and away from said pinched portion, rotation of said holder within said head light beam maintaining said biasing means in a depressed state and causing the end portion thereof to extend radially outwardly into a recess provided in said head light beam in a snap fit, the force generated by the outwardly extending arms of said biasing means being sufficient to hold said bulb in a locked position.

The biasing means is of a resilient material, preferably of a metal. Preferably, both the arms of the biasing means have a deformed protrusion substantially in the centre thereof, said protrusions extending away from said pinch portions.

In a another preferred embodiment, both the arms arms"C"shaped, the C's curving away from the pinched portion of the bulb.

In another preferred embodiment, the two arms are connected in the base thereof by a third arm so that the biasing means is substantially,"A"shaped, the pinched portion lying in a plane inside the three arms of"A".

The end portion of the biasing means extending outwardly from said holder may be tapered or rounded.

Detailed description of the invention The present invention will now be described in a greater detail with reference to the accompanying drawings wherein: Fig. 1 shows a cross section of a conventional holder including spring mechanism used in a halogen lamp.

Fig. 2A shows a cross section of an improved holder assembly including biasing means of the present invention.

Fig. 2B shows a cross section of another embodiment of the improved holder assembly including biasing means of the present invention.

Fig. 2 C shows a cross section of yet another embodiment of the improved holder assembly including biasing means of the present invention.

Fig. 4 shows a cross section of the head light beam incorporating the improved holder assembly including biasing means of the present invention.

Reference is made to Fig. 1, which discloses in cross section, a conventional holder assembly generally indicated by 1. The holder assembly 1 comprises a holder 6 and a spring means 7 mounted within said holder 6. The spring means comprises of an end portion 2 extending outwardly from said holder 6. The spring means 7 has two arms 8 secured to the inner wall of the holder 6 in the upper semicylinder thereof. The arms 8 have a bent or protruding portion 3 extending inwardly into the holder 6. Inside the holder is a slot 5 for receiving the pinched portion of the bulb (not shown). In use, the bulb is fitted into the holder with the pinched portion thereof being received into said slot 5. Thereafter, the entire holder assembly with the bulb is fixed into the neck portion of the reflector (head light beam) and rotated. The rotation of the holder assembly in the reflector causes the end portion to depress, causing tension in the spring means. When the rotation of the holder assembly 1 is completed along a pre-determined path, the end portion 2 is released into a recess in the head light beam where its snap fits into a locking position.

In use, the bulb is fitted into the holder with the pinched portion thereof being received into said slot 5. Thereafter, the entire holder assembly with the bulb is fixed into the neck portion of the reflector (head light beam) and rotated. The rotation of the holder assembly in the reflector causes the end portion to depress, causing tension in the spring means. When the rotation of the holder assembly 1 is completed along a pre-determined path, the end portion 2 is released into a recess in the head light beam where its snap fits into a locking position.

The main disadvantage of the holder assembly described above is that depression of the end portion 2 would cause the protrusions 3 to extend radially inward towards the slot 5 which receives the pinched portion of the bulb, causing the spring means to foul against the bulb or causing the pinched portion of the bulb to obstruct against the movement of the spring means.

In Figs. 2A, the first embodiment of the present invention is shown. The biasing means 90 is substantially in the shape of"A". The biasing means 90 comprises a pair of arms 70 extending downwardly around the slot 50 and fixed to the lower semicylinder of the inner cross section of the holder 60 at the position 40. The arms 70 have a bent portion 30 lying substantially in the horizontal diameter of the inner cross section of the holder 60. The arms 70 are connected to each other by a further arm 80 although, it is not essential to have such a further arm 80. When present, such arm may also act as stop means for arms 70. In use, the bulb is fitted into the holder with the pinched portion thereof being received into said slot 50.

Thereafter, the entire holder assembly with the bulb is fixed into the neck portion of the reflector (head light beam) and rotated. The rotation of the holder assembly in the reflector causes the end portion 20 to depress, causing tension in the biasing means. When the rotation of the holder assembly 10 is completed along a pre-determined path, the end portion 20 is released into a recess in the head light beam where its snap fits into a locking position.

The main advantage of the holder assembly of the present invention is that depression of the end portion 20 would cause the protrusions 30 to extend radially outwardly, away from the slot 50 which receives the pinched portion of the bulb, thereby ensuring that the pinched portion does not obstruct the movement of the biasing means and also prevents fouling of said biasing means against said bulb.

Assuming that the tensile strength of the spring or biasing means employed in the prior art and the present invention are the same, the radially inward force developed is approximately 75% higher in the present invention as compared to the prior art designs, making the lamp assembly more rigid and strong.

Figs. 2B show alternative embodiments of the present invention wherein the only the difference is in the shape of the arms 70.

In the embodiment shown in Fig. 2C, the protrusions 30 are not present. Instead, the arms 70 curve outwards in a substantially"C"shaped curvature, imparting enough resilience thereto to expand radially outwards, away from the slot 50 when the end portion 20 is depressed.

Fig. 3 shows a cross section of the headlight beam embodying the holder assembly of the present invention. As can be seen therefrom, the lugs of the holder move along the grooves 110 of the headlight beam generally indicated by 100. When the holder assembly is rotated within said headlight beam, the end portion 20 of the biasing means 10 is depressed and remains in a depressed state until it is released into the specially made recess in the headlight beam where it snap fits, holding the bulb secure in its place. The radially inward forces developed as a result of depression of the end portion 20 and opening of the downwardly extending arms 70 is so high that it renders the entire lamp assembly more rigid and strong than as seen in the conventional lamp assemblies.

It must be borne in mind that the present invention has been illustrated above with reference to the most preferred embodiment and other modifications and embodiments of the invention are possible without departing from the spirit and scope of the invention.