GB2110008A - Electrical lampholder - Google Patents

Abstract

A lampholder comprises a pair of terminal blocks (17) retained in housing slots (18). Each block (17) has an inclined bore (20) in which an input wire may be retained by a screw (21) mounted in a tapped bore (19) of the block (17), the screw also serving to retain the block in slot (18). <IMAGE>

Description

SPECiFICATION Electrical accessories The invention reiates to electrical accessories particularly 12rnsholders.

It is an object of this invention to provide for standardisatisn in the terminal arrangements of different models of lanipholders, particularly bayonet-type lam pholders with spring-loaded contact flanges.

To that end, this invention provides a lampholder comprising a lamp cap-retaining part and a contact carrying part having 3 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 contactloading aperture of said portion via a threaded bore in the block to intersect an acutely inclined wire housing in the block.

More specifically the object is achieved by terminal el blocks slid into position in slots, say between parallel ribs or walls as (above-mentioned), end retained by upper edging of such ribs or wa31s, 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 or a bayonet type lampholder permit plunger insertion.

The lampholder may also include a snap-in 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 an outer moulded part of the lampholder, and also with an inner moulded part thereof, at separate positions of the body, say a lower foot part and an upper or lateral resilient latch extension, respectively.

Figure 1 is a section through a first embodiment; Figure 2 is a section spaced from that of Figure 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 E and 9 are side and plan views of another metal liner; Figures 10, 11 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 Figures I to 4, a lampholder comprises an inner moulded part 10 for carrying cord connection tar- finals and lamp contacts, actuallyofepring-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 end inwardly directed flange '13 with the latter above the ormer, 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 18 and a terminal block 17 slid into a slot 18, 12' to be located by the spring. Each block 17 has a downwardly directed bore 19 communicating with a sansversely inclined blind bore 20 for a conductor to be entrapped and electrical contact made by a screw 21 in the tapped bore 19.The inclination 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 18,12'. Also, that inclination of bore 20 facilitates cord wire loading therein, and screw 21 ensures secure location of the terminai 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 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 sandhswiched between flanges 12 and 113.

At least the outer part 11, end 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.

Figures 6 and 7 shows lances 36 cut and pressed out of the metal liner flange 31 to give arm, 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 an alternative embodiment to that of Figures 1 to 4. Specificali^;t, a batten-mounting 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, 13 and 31 are shown riveted together at 46. Then, of course, the liner flanging 31 can be different with rivet ears 47 i.e. as shown in Figure 8 and saving metal. The same construction is shown in Figure 4 bue with outer part 4 closely com:orming to the inner part.

Figure 9 Shows a preferred J-sloQ 48 closely to scale.

Figures 10, 11 and 12 show a loop-in érminal 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 he body ate a ribbed part 52, preZer2bly ultrasonically inserted.

The drawing(s) originally filed was/were informal and die print here reproduced is taken from a later filed formal copy.

= < he body SO has a toot 53 ofT-section (Figure 12) that fits through a gap 56 in the bezel and under slotting 57, so 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 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 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 Figures 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.

Reference is made to our copending Patent Application No. 79/38676 filed 8th November 1979 which discloses a lampholder comprising a lamp cap-retaining part and a contact-mounting part to fit thereinto, wherein the lamp-cap-retaining part has inwardly-directed flanging and the contact-mounting part has outwardly-directed flanging with the former superposed in the latter when those parts are fitted together so that fitting of a lamp-cap tends to draw the parts together.

Reference is also made to our copending Patent Application No of even date which discloses a lampholder wherein said unit comprises a moulded body of insulating plastics material shaped to present cooperating parts for said location purposes, and having a terminal block mounted there inside.

Claims (9)

1. A lampholder comprising a lamp cap-retaining part and a contact-carrying part having 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.

2. A lampholder according to claim 1 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.

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

4. A lamphoider according to any one of claims 1 to 3, wherein the contact-carrying part has its or its said electrical connection-carrying portion adapted to cooperate for location purposes with a removable unit carrying an additional electrical terminal.

5. A lampholder according to claim 4wherein the lamp-cap-retaining part is also adapted to cooperate in locating said unit.

6. A lampholder according to claim 4 or claim 5, 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.

7. A lampholder according to claim 6, 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 - connection - carrying portion.

8. A lampholder according to claim 6 or claim 7, wherein said body also has a T-shaped foot to cooperate with aT-shaped slot through a peripheral edge-adjacent portion of the lamp-cap-retaining part.

9. A lampholder according to any one of claims 6 to 8 wherein the body has resilient toothed lug means to latch medially in an aperture in the electrical - connection - carrying portion.