GB2176351A - Lampholder - Google Patents

Abstract

An electrical lampholder has an inner body part (52) with slotting formed by ledging (68, 70, 72) to take a spring leaf contact (62) inserted from one side of the inner body part (52) and presenting a free end (64) for lamp cap engagement. The inner body part (52) is preferably a snap-fit (24, 28, 30, 32) in an outer part (12) which may have integral resilient leaves (24) and cover (20) of the electrical connections to the inner body part. Alternative engagement of inner and outer parts is described via resilient upstands of the inner body part. Cord grip provisions can also be readily associated with the inner body part. <IMAGE>

Description

SPECIFICATION Lampholder This invention relates to mains electrical lampholders.

Such lampholdersare well-known made up of three basic parts, namely an outer cylindrical part open at one end to take a lamp-cap, an inner part at least partially in the outer part and carrying electrical connection/contact components at its other end, and a cap fitting overthe inner part and allowing passage therethrough of an electric cord. For bayonet-type lampholders with J-slots from the open end of the outer part, electrical contact components ofthe inner partmostfrequently comprise spring-loaded plungers.

It is amongst the objects of this invention to provide an alternative lampholderconstruction that is more economical to manufacture. To such ends there are two aspects orfeatu res ofthe present invention.

One concernsthe inner part and provision of its electrical con nectio n/contact components by way of spring leaves of conductive material in an inner part whose body is moulded from insulating material with one end of each such leaf affording electrical connection at one side ofthe body and its other end. resiliently protrudingclearoftheothersideofthe bodytoafford electrical contact to a lamp cap. Such spring leaf contacts/connectors are known in themselves.

More specifically, then, it is proposed herein thatthe body of theinner part be slotted so asto accommodate a said spring leaf inserted from a side of the body, usuallytwo such leaves each into slottings from a different side of the body. Normally, ledging affording such slotting will constrain the associated spring leaf between its contact and connection portions, usually close to the latter.

Preferred slottings each have ledgings spaced in the height ofthe body to accommodate between them the thickness of a said spring leaf, say as one ledging supporting one side of the spring leaf with its free contact portion passing thereby and returned below it for resilient movement towards and away from such ledging but always spaced therefrom, and as other ledging that constrains the spring leaf at two spaced positions each to a different side ofthe one ledging and from the other side of the spring leaf.At leastthen, preferred retention formations for the constrained part of the spring leaf may conveniently comprise a small ribontheoneledging and between the spaced positions of the other edging so thatthe part ofthe spring leafto be constrained can be a flexing snap-fit oversuch rib.

It shou Id be evident that the one and the other ledgings could be at the other and the one sides of the constrgined part ofthe leafspring, respectively, and that crimp orsplice connections to the leaf spring can then very readily be hidden by extension of that other ledging relativetothe lamp contactportion ofthe leaf spring ratherthan otherwise.

In relation to lodgings for a said spring contact leaf, theone ledging can extend past the position of one of the spaced positions ofthe other ledging, say at a said spaced position past which the free contact portion curves through to a position below the inner body part for engaging a lamp contact, i.e. adjacent return bending ofthe spring contact leaf.

Provision may be made on the body for accurate location ofthe or each spring leaf, for example via a rib on the body and an indent in the inner edge of the constrained part of the spring leaf or an indent of the body adjacent its ledging and a bent over edge part of the spring contact leaf, or both. It is also preferred for a return bend of the free contact part of the spring leafto be engaged by anotherformation ofthe body. Such formation may be curved to foltow said return bend at least partially.

In relation to electrical connection parts ofthe spring leaves hereof, same may be medial of the height ofthe body at an insetthereofforwire accessto someform of termination, say a crimp or splice connection.

It is feasibleforsuch electrical connection parts to be afteranother return or partial return bend ofthe spring leaves, such other bend may be engaged by a furtherformation ofthe bodyfor leaf location purposes then perhaps avoiding any rib/indent, location feature if desired. Moreover, electrical connection parts ofthespring leaves after such other bend may be supported by body formations, say with those parts then inclined.

Accurate angular positioning ofthe inner part mlative to the outer parts is readily afforded by complementary ribs and slots, usually a rib or ribs on the inner part.

The other aspect orfeature ofthis invention concerns reduction of the aforementioned three parts to two by closing, save for a cord entry aperture, that end of the outer part, not serving for lamp entry, and effectively incorporating the aforesaid cap into the outer part. Such unitary formation ofthe outer part and the cap is also known in itself, and provision is normally madeforthe inner partto snap-fitthereinto past resilient leaves integral with the unitary part and displaced inwardly therefrom.

More specifically, then, it is proposed herein that resilient leaves integral with a moulded said unitary partbeformed at moulding so asto require only outward displacement for latching action relative to an inner part, i.e. so as notto require a setting inward displacement after mou Iding.

A preferred moulded outer part of generally cylindrical form has a medial reduction of entry crosssection to form a ledge or ledges spaced from its lamp-cap entry end and serving as an abutmentforthe inner partas its snap-in positionwhereattheouter part has integral resilient leaves, conveniently two diametrically disposed, having free latching ends that are also inwardly ledged, conveniently as disconnected extension ofthe abutment ledge or ledges.

Exterior projecting ledging ofthe innerpartto cooperate with said resilient leaves can be a slide clearance through the open end ofthe outer part but The drawing(s) originally filed were informal and the print here reproduced is taken from a later filed formal copy.

not pastthe abutment lodging.

In moulding the outer part of such specific embodiment hereof, two separable outer mould parts can form two apertures defining said resilient leaves, which mould parts mayfurtherformthread portions on partofthe exterior circumference ofthe outer part, preferably nextto aflange or otherwise enlarged portion thereof serving to locate a shade ring, even an attachment ring forsecuring the lampholder into some other structure.

It will, however, be appreciated thatthe inner part could have resilient upstands toothed to deflect past and return to engage on interior lodging ofthe outer part. Then, release thereof may be by a suitable tool insertablethrough side wall aperturing ofthe outer part above its said interior ledging.

Further preferred features ofthe inner and outer parts include pre-wiring the inner part, i.e. complete with a prescribed length of electrical cord, and pulling the inner part into snap-fitting engagement with the outer part using such cord first passed through the outerpartand/or integral formation ofcord grip portions, conveniently as resilient inwardlytoothed parts tocooperate with aferrule ring which may be a latched push fit.

Other cord grip provisions could take the form of a parthaving a suitable keying fixmentto the inner body part, as a sliding key-and-slot provision. Such part could be associated with afurther part for clamping action asa cord grip, though such other part could be integral therewith whetherfortooth-and-ratchet clamping orforteeth ata hole in an inclined part thereofto grip by pulling atthe cord.

It will be appreciated that above-noted inner body part and spring contact leaf features are equally applicable to lampholders having removable caps, i.e.

ofthree-partconstruction; also th at cord grip features are generally applicableto all types of lampholder having an inner-body part,te. whether oftwo- or three-partconstruction. Application will also be evi dentfor inner body parts and/or cord grip provisions to other types of lampholder, for example batten types.

Specific implementation ofthis invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figures 1 and 2 are opposite end views of a lampholder outer part; Figure 3 is a side view ofthe same outer part on arrowAofFigures 1 and2; Figure4 is a section through the same outer part on line B-B of Figures 1 and 2 butwith outline of an inner part installed; Figure5 is an endview ofwhat is shown in Figure 4; Figure 6 is a similar more detailed view to Figure 5 of the inner body alone; Figure 7 is the same view as Figure 6 with spring leaves fitted; Figure 8 is the opposite viewto Figure 7; Figures 9 and 10 are end and sectional views; Figure 11 is an enlarged sectional view through a spring leafinstalled; Figure 12 is a top plan view of the spring leaf;; Figure 13 shows a variant location forthe spring leaf contact; Figure 4shows a variant embodimentofinner body part; Figure 15 shows an inner body part with resilient upstands applied to a batten-type lampholder; Figure 16 shows such inner body part applied to a capped lampholder; Figure 17 shows details of a cord grip ofthe em bodiment of Figure 16; Figure 18 shows such inner body part applied to a two-part lampholder and another cord grip; and Figure 19 is a top plan viewof such body part.

In the drawings, a bayonet-type lampholder has an outerpartflanged medial at 14 between an openended tubular skirt portion 16 that will have J-slots from its open end 18 and a cap portion 20 shown with an aperture 22 for cord entry. Also medially,and shown belowtheflange 14, are diametrically opposite integral resilient leaves 24A, 24B shown thinned relative to the thickness of the skirt portion 16 from its exterior surface and connected to the skirt portion 16 in elongate apertures 26 only at ends thereof distal fromtheflangewith ends proximal totheflangol4 spaced therefrom at 288.

Internally, and convenientlyatthe position ofthe flange 14, the outer part 12 has ribs 30 and ledging at 30A, 308 shown asshoulder portions atthe positions ofthe resilient leaves 24A, 24B and registering with effective extensions thereof as latching tooth-like ends 32A, 32B of those leaves 24A, 24B.

Further illustrated details ofthe outer part 12 include arcuateth rev ded portions 34A, 34B extending from the apertures 26A,26Bfor iessthan 90 and capable of being formed with those apertures in a mould having two outer parts and a core part; tapering ofthecap portion 20 to an upper shoulder 36 and exterior strengthening ribs 38; exterior split necking 40A, 40B ofthe cap position 20 with interiorteeth formations 42A, 42B for cord gripping when constrained by a ring 44 that preferably snap-fits past outer lips 46A, 46B of the split necking 40A, 40B, see inner rib 48 and tapering mouth 50 of the ring44.

The lampholder also comprises an inner part52 that is a sliding fit into the skirt portion 16 ofthe outer part -12 and is shown with angular location means in the form of ribs 54to go in corresponding grooves 56 down the interior of the skirt portion. The inner part has ledges 58A, 58B to fitinto the spaces 28A, 28B of the apertures 24A, 248 and be returned therein over the tooth-like ends 32A, 32B ofthe resilient leaves 26A, 26B thatwill be displaced temporarily outwardly as the innerpart 52 is slipped into the skirt 16 of the outer part into abutment with the ribs 30 andshoulder portions 30A, 30B.

To each side of a central generally rectangular portion of its body the inner part 52 has side entry location slotsfor spring leaves 62A, 62B which serve as contacts and for electrical connection purposes at opposite ends or end portions 64A, 64B and 66A, 66B.

Those slots comprise ledges spaced in the height of the body ofthe inner part52 to accommodate the thickness ofthe spring leaves 62A, 62B.As shown,first ledges68A,68B are to the sides of the spring leaves nearerthe open end 18 of the outer part 1 2 and spaced ledges 70A, 70 B and 72A, 72B are to its other side. The spacings ofthe ledges 70,72 are shown correspond ing to the Lengths of the associated ledges 68.

Adjacent the latter, and outboard therefrom, are projecting ribs 74A, over which those portions of the spring (eaves that are to be constrained inthe slots formed by the ledges 68-72 have to be flexed for entering the spring leaves into the slots from opposite sides ofthe body of the inner part 12.

The electrical connection ends or end portions 66A, 66B ofthe spring leaves 62A, 62B are medially ofthe height ofthe body ofthe inner part 12 and are shown visible past edge recessing 76A, 76B, and may be wired-up by crimping or, as shown in Figure 11, by splicing 78 from either of its sides. Between their constrained portions and their contact portions 64A, 64B, the spring leaves 62A, 62B have bends 80A, 80B to return their contact-making end portions 64A, 64B back on the constrained portions atfurther bends 82.

The bends 80A, 80B then allow the contact-making end portions 64A,64Btoflexas a lamp-capentersand traverses J-slots ofthe skirt 16 ofthe outer part 12, see also Figure 11 for free, maximum deflection, and intermediate normal-contact positions.

It is preferred forthebends 80A,80B to be buttressed, see abutments 84A, 84B, and then further preferred for the constrained portions ofthe spring leaves to be accurately located, see rib 86 ofthe body of the inner part 82 and indent 88 in the spring leaf of Figures 11 and 42.

In the alternative inner part 12' of Figure 13, mounting of spring leaf 62is shown relative to lodgings 68' and 70', 72' that are inverted compared with those 68 and 70, 72 of previous figures. Now lower ledging 70' is shown extending from a shield formation 90 that hides connection portion 66' from the lamp entry side ofthe body 12'. As before, the ledgings 68 can have snap-fit ribs (not shown) and be associated with a location rib 86' now going inthe opposite direction.

Turning to Figure 74, a further alternative inner part 112 is shown in part with one other type of contact/ connectors spring leaf 162 fitted.The latter differs mainly in having an upturned connection end 166, a downturned side locater portion 165 that will usually have a returned lip at its free edge which may serve to snap onto a rib on the underside ofthe body ofthe inner part 112, see fragmental sectional view, and a larger side slot 188 to accommodate the stem of a Formation 186 affording upper ledgings by its cross-piece above lower ledging of the body. It will be evident that flattened sides of the inner part body that are indented to take the portions 165 can be matched by inner formations (not shown) of the outer part.

Additionally, the inner part body is itself shown with an upstand 140A that forms onetooth of a cord clamp ofwhich-the oth er tooth 140B is integral with the outer part, but otherwise may act as shown in previous figures.

In Figure 15, an outer part212is of batten type and has interior ledging 232A, fo r an in inner body part 252 having resilient upstands 258A, 258B to engage overthe ledging 232 after deflection on entering the inner part 252 into the skirt part 216, see also bottom flanging 259 thereof of which guidance slots or ribs can ensure (relative to mating ribs or slots of the skirt part 216) both desired angular positioning and timit- ing of entry.

Lh- Figure 16, outer part 312 is short with resilient upstands 338A, 338Bto take a snap-fitting cap 320 appropriately aperturedat321A,321 Figure 16 uses the same inner body part252 as Figure 15, see also Figure 18 and 19. In Figure 16, the inner part 252 has si-de-entry location slotting to each side of a medial barrier upstand 253 for spring leaf contacts, see 262, each engaged between upper ledging 268 and spaced lower ledging 270,272 for engaging a medial part of the spring leaf contact 262 shown with a return bend 280 pastthe lower ledging 270 to its free endfor lamp cap contact engagement. Curving abutmentformation is shown at 284forthe bend 280.The ledging 268 passes over that 270 and is actually below a support 265forinclined connection making end portion 266 of the spring leaf contact 262, a screw connector block being shown for the purpose but any other provision being possible. The spring leaf contact 262 has another bend 267 from its medial portion to the connection making part 266, and same is shown located by an upstand 273 from the ledging 272.

References 265,272,273 are subscripted Aand Bin Figure 19 for both sides ofthebarrier 253 itself subscripted Ato denote outline showing only, i.e.

omitting details ofthe upstands.

Figure 16 also shows a-cord grip provision at 240, actually comprised of two parts, one 242 of generally U-configuration (see Figure 17) with its limbs outwardly toothed as ratchets 244A, 244B and cooperating with the other part 246 having toothed aperturing, see 248 in Figure 17. The part 242 engages on the inner body part 252 via a dovetail tooth 242A and slot 242B, see also Figure 15.

As should be evident, the part 246 is pressed down by its ends over the ratchet formations to grip a cable passed between the two parts 242,246.

Figure 18 shows a variant cord-grip pmvision 340 having a similar dovetail engagement with the inner bodypart252, but being of unitary, single leaf, construction having athinning 342 and an aperture 344 with latching tooth formations 346. In use, the free limb 348 wiU be bent atthe thinning 342 to an inclined position and a cord through the aperture 344will be gripped, especially against pulling forces. Figure 18 also indicates a two partlampholderwith apertures 259to takethe inner body upstands258 and allow their disengagement.

It should be evident that the dovetail attachment of cord grip provisions is convenient and also applicable both to any desired cord grip provision and to any desired lampholder.

Lampholders hereof are, of course, accessories for mains lighting purposes,thoughthey may be used otherwise.

Claims (20)

1. An electrical lampholdersuitablefor mains lighting use, comprising an inner body part carrying lamp contact and electrical connection provisions, and an outer body part into which the inner body part fits, wherein the inner body part has slotting to accommodate at least one spring leaf contact inserted from a side of the inner body part to present a free end portion for lamp cap engagement and another end part for electrical connection to the lampholdor.

2. An electrical lampholder according to claim 1, wherein said slotting involves lodging to engage and restrain the spring leaf between its portion and from both sides ofsaid leaf.

3. An electrical iampholder according to claim 2, whereinthe ledging forces aflexing snapfitof thé .

spring Leaf into said slotting.

4. An electrical lampholder according to claim 2 or claim wherein said ledging engages one side ofthe leaf atspaced positions and the other side of theleaf medially of those spaced positions.

5. An electrical lam pholder according to claim 4, wherein a bend to the free end of the spring leaf passes one ofsaid spaced positions with said free end returning belowthatposition.

6. An electrical lampholdor according to claim 4, wherein a bend to to the free end ofthe spring leaf passes theledging medially of the spaced position with said free end returning bolowthat position.

7. An-eiectrical-lampholderaccording to any preceding claim, wherein a bendto said free end ofthe spring loaf, or said bend, engages againstanothor formation ofthe inner body part.

8. An electrical lampholderaccording to any precedingclaim, wherein the other end parts the spring leaf extends from a bend, or another bend, of the spring leaf away from the lodging.

9. An electrical lampholder according to claim 8, wherein the bend, orthe last-mentioned bend, en gages againstaformation oftheinner body part.

10. An electrical lampholder according to claim 8 or claim 9, wherein the inner body part has a support formation forthe connection part ofthe spring leaf.

11. An electrical lampholder according to any preceding claim,wherein the inner body part and an edge of the spring leaf have-interengaging formations for locating the spring leaf against movement along the length of its engagementin the slotting.

12. - An electrical lampholder according to any preceding claim, wherein the inner body part has said slotting to each sidethoroof so as similarly to accommodate two loafspring contactefor insertion from opposite sides thereof and with theirfree ends extending in opposite directions.

13. An electrical lamphoideraccording to any preceding claim, whereintheinner body partand the outer partfittogetherwith a snap action.

14. An electrical lampholderaccording to claim 13, wherein said snap-action is bymeans of resilient toothed upstandsfrom the inner body part and lodging, recessing or aperturing of the outer part.

15. An electrical lampholderaccordingto claim 13, wherein saidsnap-action is by means of resilient leaves ofthe outer part and ledging or indenting ofthe inner body part.

16. An electrical lampholder according to claim 15, wherein the outer part closes overthe inner body part save for a cord entry aperture through the outer part.

17. An electrical lampholderaccording to claim 15 orclaim 16, wherein the resilient leaves of the outer part are integral below an interior ledge orange and displaceable bythen latchable on ledging orflanging ofthe inner body partto buttagainstthatoftho inner part.

18. An electrical lampholder according to any precedingclaim, wherein the inner bociy partlaas cord grip provision.

19. An electrical lampholdoraccording to claim 18, wherein the cord grip is by means of a partor parts fitting tothe inner body part.

20. An electrical lampholder substantiallyas herein described with reference to and as shown in the accompanying drawings.