GB2063584A - Electrical accessories - Google Patents

Abstract

A lampholder (Fig. 2) comprises an inner moulded part (10) for carrying connection terminals and lamp contacts and having an outwardly directed flange (12). An outer part 11, and also a metal liner 30, have an inwardly directed flanges (13, 31) and lamp cap anchorages. Spring loading of lamp contacts means that a fitted lamp cap tends to hold the parts together. Other features include connection terminal blocks (17) retained in housing slots of the inner part partly by their connection screws (21) that intersect inclined wire-loading bores (20), a removable loop-in terminal unit (50 in Fig. 11) located on the inner part, and aperturing of the outer part (11) to overfit the inner part (10) with complementary configurations that ensure non-rotatable relative location. <IMAGE>

Description

SPECIFICATION Electrical accessories The invention relates to electrical accessories particularly lampholders.

Customarily, lampholders have a part that affords electrical contacts to a bulb cap, often by spring loaded plungers or other contact elements, and another part by which a lamp cap is retained against those electrical contacts. There is X tendency, that will be accentuated by usual spring loading, for operative positioning of a bulb cap to apply separation forces to those two parts. Hitherto that has been opposed by rivetting or screw-threading, and we have ourselves recently proposed a nesting interengagement of the two parts. It is one object of this invention to provide an alternative and advantageous arrangement of those parts.

To that end, one aspect of this invention provides that such parts be oppositely flanged, one inwardly and the other outwardly, and assembled with flanges superposed so as to be drawn together by lamp mounting.

In preferred embodiments an outer, generally cylindrical, lamp-cap-retaining part has upper inwardly-directed flanging and an inner, contact-mounting part has lower outwardlydirected flanging. Then, simple placement of the outer part over the inner part will secure the desired objective and facilitate assembly.

Both of such parts may be mouldings of synthetic plastics materials. However, a most satisfactory form of lamp-cap retainer is a cylindrical metal sleeve conventionally referred to as a metal liner. Highly advantageous implementation of this invention is achieved using such a metal liner as the outer part, but preferably with its flanging sandwiched between said flanging of the inner part and.an outer moulded part also having inwardly-directed flanging. The latter outer moulded part may be to the full depth of the metal liner or be short thereof leaving a so-called exposed metal liner, with which the lamp cap engages by J-slots of bayonet-type couplings or threads of Edison-screw-type couplings.

Securement of contact-carrying and lampcap-securing parts against relative rotation has often been by said rivetting, screwing or the like and that can be employed herein. However, and especially when using a sandwiched flanged metal liner, another aspect of this invention concerns the formation of inward flanging of the lamp-securing part and/or the outer moulded part to present an inward configuration that is complementary to the exterior of the contact-carrying part at the relevant position on a portion thereof extending to carry connection terminals, so as to restrict relative rotation simply on fitting of the former over the latter. An elongate formation of the latter with ribs flanking or dividing terminalblock positions is advantageous.For a sandwiched metal liner, especially of bayonet-type and with a full length outer moulded part, so forming the latter may also serve accurately to register its J-slots with those of the liner.

It will, of course, be appreciated that the aforesaid rivetting or screwing also prevents separation of the contact-carrying and latr,;.

cap securing parts in the direction opposite to their drawing together. However, that is readily attained herein by the simple expedient of forming such parts to snap-fit together, especially when both are plastics mouldings or when a metal liner is sandwiched by such plastics mouldings.

One advantage of our preferred sandwich construction is in permitting the use of thermoplastics material, such as glass-fibre reinforced nylon, for the outer moulded part without risk of unacceptable thermal degradation in use.

Another particular advantage of our proposal for moulded plastics inner and outer flanged parts is that only the extent and configuration of the uppermost portion and exterior of the outer part needs to be varied for different models of lampholders, for example batten-fixing types provided with an exterior retention flange or bezel and capped types provided with an exterior abutment flange below a threaded neck for the cap.

Further in the interests of standardisation, we also propose herein, and with particular reference to bayonet-type lampholders and spring-loaded contact flanges, that terminal arrangements be invariant from model to model. This, we find, is conveniently achieved by terminal blocks slid into position in slots, say between parallel ribs or walls as abovementioned, and retained by upper ledging of such ribs or walls, with contact screws in threaded bores from exposed top parts of the blocks, which threaded bores intersect with cord wire bores that are acutely inclined to said threaded bores to maximise ease of connection into mains wiring. Exposure of the top parts of the blocks is advantageously by apertures that for a bayonet type lampholder permit plunger insertion.

At least one other provision hereof is believed to have inventive merit, namely a snapin facility for an additional terminal by means of which loop-in wiring may be achieved.

Thus, a moulded body containing the desired additional terminal may be formed to interengage with both a conforming formation of the outer moulded part of our preferred lamp holder, and also with the inner moulded part thereof, at separate positions of the body, say a lower foot part and an upper or lateral resilient latch extension, respectively.

Finally, we mention the possibility that a sandwich construction as aforesaid with an exposed metal liner may have the free end of the latter outwardly flanged or flared, generally or iocally, in order to permit the overfitting and retention of a moulded cylindrical part so as insulatingly to cover the otherwise exposed portion of the liner. Relative axial and/ or rotational movement is prevented by abutment of the upper edge of the cylindrical part on the bottom of the outer moulded part and its lower edge on the flanging or flaring of the metal liner. That lower edge may, of course, be inwardly rebated to extend at least to the limit of the liner. The upper edge may be toothed or otherwise formed for anti-rotation cooperation with the bottom of the outer moulded over.

Figure 1 is a section through a first embodiment; Figure 2 is a section spaced from that of Fig. 1: Figures 3 and 4 are side and plan views; Figure 5 is a part section through a second embodiment; Figures 6 and 7 are plan and side views of one metal liner; Figures 8 and 9 are side and plan views of another metal liner; Figures 10, 1 7 and 12 are section, top and end views of a preferred loop-in terminal; and Figure 13 is a part sectional view showing an alternative loop-in terminal arrangement.

In Figs. 1 to 4, a lampholder comprises ari inner moulded part 10 for carrying cord connection terminals and lamp contacts, actually of spring-loaded plunger-type for a J-slotted bayonet type of outer moulded part 11. The inner part 10 has an outwardly directed flange 12, and the outer part 11 an inwardly directed flange 1 3 with the latter above the former, as achieved very readily by assembling the outer part 11 onto the inner part 10.

Plunger housings, such as 14, are provided one to each side of a central portion 1 5 of the inner part 10. The plunger will be spring loaded and telescopic or held at the end of a spring retained between a ledge 1 6 and a terminal block 1 7 slid into a slot 18, 18' to be located by the spring. Each block 1 7 has a downwardly directed tapped bore 1 9 communicating with a transversely inclined blind bore 20 for a conductor to be entrapped and electrical contact made by a screw 21 in the tapped bore 1 9. The inclination of the bore 20 allows one end face 24 of the block 1 7 to be stepped to abut on sidewall 22 of the inner part 10 at one side of slot 18, 18'.Also, that inclination of bore 20 facilitates cord wire loading therein, and screw 21 ensures secure location of the terminal block 1 7 by its accommodation in a plunger loading hole 23, 23' at the top of inner part 10.

It will be obvious, that the use of springloaded plungers in the inner part 10 and lamp-cap anchorages (J-slots) in the outer part will cause the flanges 12 and 1 3 to be drawn together simply by lamp-cap fitting.

A metal liner 30 is shown as the main lamp retainer element and that too is inwardly flanged 31 at its top and sandwiched between flanges 12 and 13.

At least the outer part 11, and preferably also the metal liner 30 are snap fits over flarings 32 on the sides of spaced ribs 33, 34 of the inner part 10.

Figs. 6 and 7 shows lances 36 cut and pressed out of the metal liner flange 31 to give a firm, rattle-free assemblage regardless of in-tolerance variations of the moulded parts 10 and 11.

Fig. 6 also shows that the flanging 31 of the metal liner 30 has an elongate aperture 37 to fit snugly on the central portion of the inner part and thereby locate against relative rotation.

The lampholder of Figs. 1 to 4 is of a capped type and has an exterior flange 40 on the outer part 10 with threading 41 thereabove for the cap and threading 42 therebelow for a shade ring.

Fig. 5 shows an alternative embodiment to that of Figs. 1 to 4. Specifically, a battenmounting type of lampholder is shown with its outer part 11' formed with a top bezel 44 above an exterior threading 45 for threaded collar clamping. Also, the flanges 12, 1 3 and 31 are shown rivetted together at 46. Then, of course, the liner flanging 31 can be different with rivet ears 47 i.e. as shown in Fig. 8 and saving metal. The same construction is shown in Fig. 4 but with outer part 4 closely conforming to the inner part.

Fig. 9 shows a preferred J-slot 48 closely to scale.

Figs. 10, 11 and 1 2 show a loop-in terminal as an additional and optional terminal body 50 of moulded insulating plastics material containing a metal terminal block 51 of screw-clamp type let into the body at a ribbed part 52, preferably ultrasonically inserted.

The body 50 has a foot 53 of T-section (Fig. 12) that fits through a gap 56 in the bezel and under slotting 57, 58 for retention against separation of the body 50 and the outer part 11' axially of the lampholder. At the other side of the terminal block, the body 50 has a top extension or arm 59 with an end tooth 60 that snaps over a slide 61 and into a slot 62 in the top of the inner part 10.

Obviously, the loop-in terminal body 50 will normally be fitted only to a batten mounting type of lampholder.

An alternative loop-in terminal is shown in Fig. 1 3 as a body 50' having a plug-in fitment by resilient ears 63 in a hole 64 in the inner part 11'. Then, the body 50 need have no more than a slot engager 65 rather than the T-shaped foot 55, but a key and key-way may be preferred for additional resistance to axial dislocation.

The loop-in terminal of Figs. 10 and 11 is preferred as no aperture is then required in the inner part 10, which could be weakening or cause moulding problems.

Finally, dashed lines 70, 72 show respectively, a slip-on insulating tube about an exposed metal liner, and a flaring of the free end of the latter to give axial location. This allows ready conversion between escaped and insulated liner types. Anti-rotational location may be secured by the flaring 72 being localised, or additional flaring of the top of the J-slot, or by lug or toothed interlocation of the upper edge of the tube 70 with the outer moulded part.

Claims (29)

1. A lampholder comprising a lamp capretaining part and a contact-carrying part to fit thereinto, wherein the lamp-cap-retaining part has inwardly-directed flanging and the contact-carrying part has ;outwardly-directed flanging with the former superposed on the latter when those parts are fitted together so that fitting of a lamp-cap tends to draw the parts together.

2. A lampholder according to claim 1, wherein the flanging of the lamp-cap-retaining part snap-fits under a projection or projections on an upwardly extending connection-terminal-carrying portion of the contact-carrying part.

3. A lampholder according to claim 1 or claim 2, wherein the lamp-cap-retaining part is of metal.

4. A lampholder according to claim 3, further comprising an outer part which also has inwardly directed flanging to superpose the other flangings and coact with the contact-carrying part to sandwich that metal lamp-cap-retaining part.

5. A lampholder according to claim 4, wherein the outer part snap-fits under a or said projection or projections on a or said upwardly extending connection terminal-carrying portion of the contact-carrying part.

6. A lampholder according to claim 4 or claim 5, wherein the contact-carrying and outer parts and plastics mouldings.

7. A lampholder according to claim 6, wherein the contact-carrying part is of thermosetting plastics material and the outer part is of thermoplastics material.

8. A lampholder according to claim 7, wherein the thermoplastics material has reinforcing inclusions such as glass fibre.

9. A lampholder according to any one of claims 4 to 8, wherein the outer part extends over substantially the whole outer periphery of the metal part.

10. A lampholder according to any one of claims 4 to 9, wherein the outer part stops short of the lamp-cap-retaining formation or formations of the metal part.

11. A lampholder according to any one of claims 4 to 10, wherein the outer part is exteriorly formed with a flange between threaded upwardly and downwardly extending portions that serve in securement of a terminal cover and a shade ring, respectively.

1 2. A lampholder according to claim 11, wherein the outer part has an upper exterior flange or bezel to serve in its mounting using a union ring on a threaded downwardly extending portion.

1 3. A lampholder according to any preceding claim, wherein the superposed fiangings are apertured and fixed together therethrough, to prevent relative rotation.

14. A lampholder according to any one of claims 3 to 11, wherein the flanging of the metal part has its interior edge or a part or parts thereof shaped to present a configuration complementary to an upwardly extending connection-terminal-carrying portion of the contact-carrying part to serye in restricting relative rotation.

1 5. A lampholder according to claim 14, wherein the outer part also has its interior edge configured to cooperate with the terminal-carrying portion to restrict relative rotation.

1 6. A lampholder according to any one of claims 3 to 14, wherein the flanging of the metal part has one or more portions partially struck out therefrom to form resilient projections that ensure rattle-free assembly.

1 7. A lampholder according to any preceding claim, wherein a or said connectionterminal-carrying portion of the contact-carrying part has housing slots therein for connection-wire blocks, with such said blocks each retained therein by cooperation with its said slot and a wire-connection screw extending into a contact-loading aperture of said portion via a threaded bore in that block to intersect an acutely inclined wire-housing bore in the block.

1 8. A lampholder comprising a contactcarrying part having a connection terminalcarrying portion that has housing slots therein for connection-wire blocks, with such said blocks each retained therein by cooperation with its said slot and a wire-connection screw extending into a contact-loading aperture of said portion via a threaded bore in the block to intersect an acutely inclined wire housing in the block.

1 9. A lampholder according to claim 1 7 or claim 18, wherein the said blocks engage ledges of their housing slots, and said threaded and wire-housing bores are from top and exposed side faces of said blocks, respectively.

20. A lampholder according to claim 19, wherein the said slots extend transversely of the lampholder and the ends of them and of the blocks are stepped, so as to cooperate in limiting block insertion at faces into which said inclined bores are set, those faces also being inclined to facilitate wire insertion.

21. A lampholder according to any preceding claim, wherein the contact-carrying part has its or its said electrical connectioncarrying portion adapted to cooperate for location purposes with a removable unit carrying an additional electrical terminal.

22. A lampholder comprising a lamp-capretaining part and a contact-carrying part, and the latter is adapted at its electrical-connection-carrying portion to cooperate for location purposes with a removable unit carrying an additional electrical terminal.

23. A lampholder according to claim 21 to claim 22, wherein the lamp-cap-retaining part or a or said superposed outer part, is also adapted to cooperate in locating said unit.

24. A lampholder according to claim 21, 22 or 23, wherein said unit comprises a moulded body of plastics material shaped to present cooperating parts for said location purposes, and having a terminal block mounted thereinside.

25. A lampholder according to claim 24, wherein said body has a resilient extension arm to locate over a ledge or in a slot or hole at the free end of said electrical-connectioncarrying portion.

26. A lampholder according to claim 25, wherein said body also has a T-shaped foot to cooperate with a T-shaped slot through a peripheral edge-adjacent portion of the lampcap-retaining part or outer part.

27. A lampholder according to claim 24, wherein the body has resilient toothed lug means to latch medially in an aperture in the electrical-connection-carrying portion.

28. A lampholder comprising a lamp-capretaining part and a contact-carrying part with the former apertured to over fit the latter with complementary configuration of the aperture of the lamp-cap-retaining part to cooperate with an upwardly extending connection-terminal-carrying portion of the contact-carrying part to restrict relative rotation.

29. A lampholder arranged and adapted to operate substantially as herein described with reference to any one or related ones of the Figures of the accompanying drawings.