GB2110009A - Electrical lampholder - Google Patents

Abstract

A lampholder of the batten-mounting type comprising a) an inner moulded part (10) for carrying connection terminals and lamp contacts and b) an outer part (11') for retaining a lamp cap, additionally has a removable loop-in terminal unit (50) located on inner part (10). Terminal unit (50) may have a toothed arm (59, 60) for engaging a slot (62) in inner part (10) and a foot (53) (or resilient ears) for engaging slots (57, 58) in outer part (11'). <IMAGE>

Description

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

In our copending Patent Application No. 79/38676 filed 8th November, 1979 we disclose a lampholder comprising a lamp cap-retaining 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 form superposed on the latter when those parts are fitted together so that fitting of a lamp-cap tends to draw the parts together.

In our aforesaid Patent Application it is further disclosed that preferred embodiments of lampholder comprise an outer, generally cylindrical, lampcap-retaining part having upper inwardly-directed flanging and an inner, contact-carrying part having lower outwardly-directed 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 inwardiy-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 lamp-capsecuring 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 the invention of our aforesaid Patent Application concerns the formation of inward flanging of the lamp-securing part and/orthe outer moulded part to present an inward configuration that is complementary to the exterior of the contactcarrying 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 terminal-block 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 lamp cap securing parts in the direction opposite to their drawing together. Howev er, 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 the preferred sandwich construction is our aforesaid Patent Application 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 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.

Also disclosed in our aforesaid Patent Application and disclosed and claimed in our copending Patent Application No. of even date is the feature that the contact-carrying part has a connection terminal-carrying 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.

This permits standardisation, particularly with reference to bayonet-type lampholders with springloaded contact flanges, ofterminal arrangements from model to model of lampholder.

The present invention is concerned with a particulav aspect of the lampholders as disclosed in the aforesaid Patent Applications, namely a snap-in facility for an additional terminal by means of which loop-in wiring may be achieved.

Thus according to this invention there is provided a lampholder of the batten-mounting type comprising a lamp-cap-retaining 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.

It is to be noted that this particular invention is concerned only to a batten mounting type of lampholder.

In the accompanying drawings there is illustrated both bezel and capped and batten mounting types of lampholders. For example Figures 1 to 4 illustrate a bezel and capped type of lampholder while Figures 5 and lotto 13 illustrate a batten mounting type of lampholder.

Many features are common to the two types and it is for this reason the both are illustrated and described but it is reiterated as aforesaid that the present invention is concerned with the latter type.

In the drawings: Figure lisa section through a bezel and capper type lampholder; The drawing(s} originally filed was/were informal and the print here reproduced is taken from a later filed formal copy. Figure 2 is a section spaced from that of Figure 1; Figure 3 and 4 are side and plan views; Figure 5 is a part section through a batten Figures 6 and 7 are plan and side views of one metal liner which can be used in both types.

Figures 8 and 9 are side and plan views of another metal liner which can also be used in both types; Figures 10, 11 and 12 are section, top and end views of a preferred loop-in terminal for use in the lampholder of Figure 5; and Figure 13 is a part sectional view showing an alternative loop-in terminal arrangement, also for use in the lampholder of Figure 5.

In Figures 1 to 4, a lampholder comprises an 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 13 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 15 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 16 and a terminal block 17 slid into a slot 18, 18' to be located by the spring. Each block 17 has a downwardly directed tapped bore 19 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 19. The clination of the bore 20 allows one end face 24 of the block 17 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 17 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 spring-loaded plungers in the inner part 10 and lamp-cap anchorages (J-slots) in the outer part will cause the flanges 12 and 13 to be drawn together simply by iamp-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, of the inner part 10.

Figures 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.

Figure 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 Figures 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.

Figure 5 shows a batten-mounting type of lam pholder to which the present invention is applied with its outer part 11' formed with a top bezel 44 above an exterior threading 45 for threaded collar clamping. Also, the flanges 12, 13 and 31 are shown rivetted together at 46. Otherwise this lampholder is substantially as illustrated and described with reference to Figures 1 to 4. The liner flanging 31 is different with rivet ears 47 i.e. as shown in Figure 8 and saving metal. The same construction is shown in Figure 4 but with outer part 4 closely conforming to the inner part.

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

Figures 10, 11 and 12 show a loop-in terminal for incorporation in the lampholder of Figure 5, which is additional to terminal blocks 17 and which has a 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 (Figure 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.

An alternative loop-in terminal is shown in Figure 13 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 ratherthan 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 Figure s 10 and 11 is preferred as no aperture is then required in the inner part 10, which could be weakening or cause moulding problems.

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 locatised, 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 moulder part.

Claims (16)

1. A lampholder of the batten-mounting type comprising a lamp-cap-retaining part and a contactcarrying 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.

2. A lampholder according to claim 1 wherein the lamp-cap-retaining part is also adapted to cooperate in locating said unit.

3. A lampholder according to claim 1 or claim 2, 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.

4. A lampholder according to claim 3, wherein said body has a resilient extension arm to locate over a ledge or in a slot oF hole at the free end of said contact-carrying part.

5. A lampholder according to claim 4, wherein said body also has a T-shaped foot to cooperate with a T-shaped slotthrough a peripheral edge-adjacent portion of the lamp-cap-retaining part.

6. A lampholder according to any one of claims 4 to 6, wherein the body has resilient toothed lug means to latch medially in an aperture in the contact-carrying part.

7. A lampholder according to any one of the preceding claims, wherein the lamp-cap-retaining part has inwardly-directed flanging and the contactcarrying 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.

8. A lampholder according to claim 7, 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.

9. A lampholder according to any one of the preceding claims, wherein the lamp-cap-retaining part is of metal.

10. A lampholder according to claim 9, further comprising an outer part which also has inwardly directed flanging to superpose the other flangings and coach with the contact-carrying part to sandwich that metal lamp-cap-retaining part.

11. A lampholder according to claim 10, 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.

12. A lampholder according to claim 10 or claim 11, wherein the contact-carrying and outer parts are plastics mouldings.

13. A lampholder according to any one of claims 10 to 12, wherein the superposed flangings are apertured and fixed together therethrough to prevent relative rotation.

14. A lampholder according to claim 9, 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 con nection-terminaScarrying portion of the contact-carrying part to serve in restricting relative rotation.

15. 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.

16. A lampholder according to any one of claims 9 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.