US2313212A - Electrical socket - Google Patents

Description

March 9, 1943. M. ALDEN I 2,313,212

ELECTRI CAL SOCKET Filed Nov. 8, 1938 2 Sheets-Sheet 1 March 9, 1943.

M. ALDEN EL EcTRicAL SOCKET' Filed Nov. 8, 1938 f 2 Sheets-Sheet 2- I INVENTOR MLZ ZonA BY Patented Mar. '9, 1943 UNITED STATES PATENT OFFICE EIECTRICAL SOCKET Milton Alden, Brockton, Mass. Application November a, 1938, Serial No. 239,424

- '1 Claims. (01. 173-328) This invention pertains to an electric socket and a process for the manufacture of such socket.

My invention is especially suited to the manufacture of small electric sockets such as are employed to contain low voltage electric bulbs, as the so-called miniature type bulbs used for dial lights on radio receivers and the like.

One object is-to provide a simple and inexpensive socket which is effective and durable. As a portion of the process of manufacture, my invention includes a novel method of forming a centre contact for an electric socket of the type described, directly upon the end of an insulated wire.

Another purpose of this invention is to produce an electric socket in which there is no possibility of the insulation of an electric wire attached thereto being disturbed in such fashion that the bare conductor can come in contact with undesired portions of the socket, thereby causing short-circuits to occur. This is a difiiculty which has been very troublesome in the structures of the prior art, especially as used in connection with dial lights on radio receivers, and the remedies which have been used in an attempt to overcome this trouble have either been unsatisfactory or unduly expensive, or both; such remedies including the provision of insulation in more or less complicated shapes, such insulation being either formed of materials such as of the phenolic condensation type, or. formed of soft rubber. In the present-day art, it is necessary that the components entering into the construction of a radio receiver shall be of comparatively low cost, and the various expedients which have been above mentioned for the proper protection of a. dial light socket from accidental short-circuits due to the exposure of a bare wire within, or adjacent to, the socket, have all added unduly to the cost of the socket, and additionally have often not been wholly satisfactory.

A further object of my invention is to provide a socket of the character described which may safely be used upon radio receivers of the so-called universal type, wherein portions of the power circuit feeding the receiver are directly connected to the dial light, so that the socket used with such light must be able to afford adequate insulation, withstanding potentials of the order of 100 to 200 volts, since accidental contact of the wire or contact connected to or belonging to such a socket with other portions of the receiver will not only bring about the possibility of danger to the other components of the set which may be damaged by abnormal voltages, such as'the, tube filaments, filter condensers, etc., and possible shock tc the operator of the receiver, but such contact also prevents a gravefire hazard, due to the fact that almost any accidental contact which may be made will be practically certain to give rise to an electric spark, or even to a dangerous are at the point of contact, due to the comparatively high voltages involved.

Another purpose of this invention is to produce a dial light socket which can easily be assembled into place and connected by the radio set manufacturer with a minimum of time and labor.

Yet another purpose of this invention is to provide a dial light socket which can readily and without the use of tools, be adjusted along a given supporting member, so that when used with bulbs of varying size, an adjustment may easily be made to give maximum illuminating efliciency. Furthermore, these same means which allow the ad-' justment of position just mentioned, contribute to the ease of replacement of a bumed-out bulb, since they allow the socket to readily be moved, by the layman if necessary, away from its position closely adjacent the dial, so that more space will be available for manipulating the bulb during removal and replacement. This advantage is of great importance, especially in the case of the extremely compact receivers of the present day.

currence of short circuits due to such contacts,

which would be undesirable for reasons previously mentioned and is especially a prime requisite for dial light sockets to be used in universal type receivers which may be carrying line voltage directly to the dial light.

Another purpose of my invention is to provide a method of assembly of an electric socket and a conductor leading therefrom, which includes assembling one portion of the socket structure into permanent mechanical and electrical connection with the conductor, and then assembling this portion, together with its attached conductor,

into a unit with the remainder of the socket.

A still further purpose of this invention is to provide a method of forming an electrical con- Another object of this invention is to provide as an article of manufacture, a unitary structure incorporating a dial light socket, a portion of the conductor or conductors supplying current to the socket, and a clamp for mounting the socket in position in'a radio receiver.

Further objects of my invention will be apparent from the followihg specification thereof, and from the drawings annexed hereto, where Figs. 1, 2, 3, 4 and 5 illustrate in perspective various steps in the formation of a metal shell of my socket.

Figs. 6 and 7 illustrate the formation of an eyelet so as to serve as a contact member for such socket.

Fig.8 shows the assembly of a conductor with the eyelet.

Fig. 9 is a side elevation, partly in section, an alternative form of eyelet.

Fig. 9a. shows in end elevation the alternative form of Fig. 9, illustrating another method of assembling a wire and an eyelet without the use of solder.

Fig. 9b shows in section a detail of the assembly of Fig. 9a.

Fig. 10 shows one stage parts.

Fig. 11 shows of assembly of socket the next stage of assembly, in

section on the line of Fig. 12.

Fig. 1 is an end elevation view of a completed socket of the single contact type according to my invention.

Fig. 120, is a side elevation in section of a variant form of the socket of Figs. 11 and 12.

Fig. 13 is a perspective view of the structure of Figs. 11 and 12 but also including a lamp in position therewithin and illustrating one method of mounting my socket.

Fig. 14 is a perspective view of a double contact type socket proper, with the exterior protective shells removed therefrom.

Fig. 15 is a perspective view socket of the double contact type.

Figs. 16, 1'7 and 18 show steps in the assembly of the socket of the double contact form shown in Figs. 14 and 15.

Fig. 19 is a rear elevation of the double contact type of socket partly in section on the lines |9-|9 of Fig. 17.

Fig. 20 is an end elevation of another form of insulating sleeve, for the double contact type of socket.

The shell of the socket is preformed by steps as shownin Figs. 1 to 5.

A flat sheet of suitably flexible metal such as quarter-hard stock, is here shown in the forms which it successively assumes as it is subjected to a series of forming operations by any suitable mechanical means, such as punchi swedging,

of a complete etc. These series of operations may be performed upon a continuous strip of metal stock as it .passes progressively through a series of dies,

which may operate simultaneously upon different portions of this strip,- so that extremely rapid and economical production is possible.

In Fig. l, the strip 2|) is sho 2|, 2|, recesses 22 along one edge, and projecting 1 ears or tabs 23, 23 along the same edge. The next with apertures stage is shown in Fig. 2, where one shorter edge 24 has been bent at a suitable angle, such as approximately 45", and the opposite edge 25 has been bent slightly, together with the adjacent portions of the longer edges, so as to form a surface which can slide easily upon another surface, without any undue friction or engagement of edges therewith. Likewise there have been formed two ridges 26, 26 somewhat adjacent the apertures 2|.

In Fig. 3, the metal strip has been subjected to a further operation which has bent up two major ridges 21, 21 extending completely across the strip. These ridges preferably have gently sloping sides and do not rise at an abrupt angle from the surface of the strip.

In the stage of formation illustrated by Fig. 4. the apertures 2| have been extended until they reach the edge of the strip and are of a form suitable for the reception of the pins of a bayonet type base dial light.

Likewise in the form shown in Fig. 4, the lower portion 28 of the strip has been bent up in the manner shown, and the ears 23 have been bent at right angles to the body of the strip.

Fig. 5 is a perspective view showing the strip bent around in an are, but with the extremities of the are still separated, so that it is-possible easily to insert the interior members of the socket within this arcuate strip, the substantially complete closure of which will then imprison such interior members, to be described afterwards, within the shell of the socket formed in this fashion. The upturned ears 23, 23 and the small ridges 26, 26 will then function to prevent the escape of the interior members from the respec- 30 and has the lip at its other end rounded off inwardly as shown at 3|, so that its interior diameter is slightly smaller at this point. A suitable machine tool, such as a press, which is capable of forcing the eyelet into the configuration shown in Fig. 7, is next employed. It will be noted that v in Fig. 7 a bulge or ridge 32 has been formed around the periphery of the eyelet and that the rim 3| has been still further bent inwardly.

The purpose of the operations just described as performed upon the eyelet will be apparent upon a consideration of Fig. 8, which shows the wire 33 having a portion 34 bared of insulation, threaded at least partially through the hollow eyelet 29 and fastened thereto near the surface of the flange 30 or within the hollow portion of the eyelet by solder 35. It is tobe understood that the wire is threaded within the eyelet while the latter is in the condition indicated by Fig. 6, and that when the eyelet has assumed the condition shown in Fig. 7, the wire is already enclosed within, so that the assembly is as shown in Fig. 8. The turnedin rim, 3|, thus bites into the insulation at the rear portion of the wire, so as firmly to hold the wire and the eyelet together. Ridge 32 performs a function later to be described in connection with Fig. 11.

Referring now to Figs. 9 and 911, there is shown in vertical elevation an alternative method of fastening thewire into the eyelet without the use of solder. The eyelet is here shown as provided with a conical flange 3B and with a centrally located aperture 36'. The wire may be out without any projecting bared portion, and the eyelet placed in a press or other similar device which will flatten out the conical flange 30' as shown in the sectional view of Fig. 9b. This action forces the 'bare core 34 of the wire 33 through the aperture 36' and forms ridges 36 on the flattened surface of the flange 30', at the same time squeezing the wire tightly in the aperture 36 which is rendered smaller by this operation, so that soldering may be dispensed with if desired, since the mechanical connection thus aflorded is extremely secure and may be made tin to-tin or silver to silver if so desired, thus obviating corrosion of the bare copper or brass. However, soldering may additionally be practiced if so desired.

In Fig. 10, there is shown in elevation an assembly such as that of Fig. 8, upon which have been threaded two additional elements which go to make up the interior portions of my socket. A washer 31 of any suitable insulating material such as flbre is slipped over the wire, with a helical spring 38 behind it. Referring now additionally to Fig. 11, the metal body is shown completely closed together around a washer 39, also of suitable insulating material such as fibre, retained in the rear end thereof by the bent over ears 23,

already described. The ridges 2G, lie towards the front of the body and in Fig. 11 the washer 31 is shown lying behind these ridges which serve to rear portion and allowing the rear washer 39 of Fig. 11 to be dispensed with. In the assembly of this form of socket, the washer 31 may be inserted at an angle and the socket body spring open enough to allow the washer to pass shoulders 23, 23, thus causing spring 38 to b under compression.

Fig. 13 is a perspective view which further illustrates the formation of the holder and shows how apertures 2| function to receive the pins of a bayonet lamp base, so as to retain the lamp within the socket, as well as illustrating how the frictional engagement of the holder allows the socket to be moved along support 46, for adjustment to accommodate lamps of various sizes or for replacement of lamps with greater ease.

My invention is also applicable to the formation of a completely insulated socket of the two retain it within the body of the socket. Likewise flange is shown lying against the outer surfaceof this washer. On method of assembling this structure is to feed the wire through the washers 31 and 39 and by the use of a suitable tool such as a simple rod to force the flange back, thus causing the washer 31 to ride over the ridge 32 and at the same time forcing it back of the ridges 28, 26. Alternatively, washer 31 may be threaded over the eyelet before the latter has assumed the form shown in Fig. 7, 1. e.; before the bulge 32 has been produced upon the eyelet so that it will be unnecessary to force it over this bulge 32, which serves to prevent it from slipping backwards after assembly. The ridges 32 may be closely adjacent the washer or considerably to the rear thereof, as may bedesired. It will be seen that after the assembly shown in Fig; 11 has been made, both washers are retained'within the outer socket shell and that any pressure upon washer 31, or upon contact flange 30 wilLresult in alat eral movement of this washer towards the rear washer, at the same time compressing the spring 38. This insures an elastic or resilient contact with the base or central contact of an inserted lamp. It will be noted that the spring 38 is small enough so that the wire 33 keeps it from touchwire type, where the electrically active shell of the socket is to be protected from accidental contact with other parts of a radio receiver. The general method of manufacturing is similar to that already described, except that the body or shell of the socket proper is not provided with the portions 24, 25 and 28 which coact to form the support in the case of the single socket. However,

. as shown in Fig. 14, a tongue 40 is formed so as to extend out of the body, and tothis tongue, the bared end of another when may -be attached by solder as shown at 4|. Tongue 40 may then be depressed so as to lie close to the shell body 20 In Fig. 15 there is shown in perspective the completely assembled double contact type socket, and Figs. 16, 17 and 18 show detail steps of the assembly of such type socket, the elements not specifically described bearing numbers corresponding to similar parts in the single contact type already illustrated. Over the partial assembly shown in Fig. 14 there is slipped a suitable insulating sleeve 42, formed of stiff or flexible fibre, rubber, or the like, which is long enough to project considerably forward of the ing the body 20 of the socket, and that its ends rest upon the insulating washers 31 and 39 respectively. Thus this spring cannot make an unwanted contact, resulting in a short-circuit. Due to the presence of ridge 32, the eyelet 29 and the washer 31 operate as a single unit when lateral compression of the spring takes place.

Fig. 12 is a front end view in elevation of the complete assembly as ready to receive a lamp 39' (Fig. 13), therein, showing how ridges 26 retain washer 31 in place and how the edges 24 and 25 of the shell body partly overlap so as to form a holder for the socket.

Fig. 12a illustrates a variant form of the socket shown in Fig. 11, in which spring 38 is made of larger diameter so as to rest directly against ears 23, thus confining the contact assembly at its body proper 20' of the socket, thus affording complete protection for the base of an inserted lamp.

One method of assembly is to put the insulating sleeve 42 over the body 2|),v thread wire 33' through a channel 43 provided laterally of sleeve 42, solder the baredend of the wire to tongue 40, bend this tongue flat against the body 20 and then push the socket proper completely within the insulating sleeve 42. The assembly of the central contact is preferably made within body 20 in the manner already described for the single contact type, before any other of the above described operations are performed. As shown in Figs. 15, 16 and 17, an additional outer metallic shell, 44 very similar to that used for the socket proper of the single contact type device, is provided with ears 45, which are sprung inwardly and serve to press firmly the insulating shell 42 against body 20', thus locking together the complete assembly. Shell 44 also has retaining ears 23' similar to those on the socket proper. Shell 44 is electrically dead, in so far as connections to the lamp socket are concerned, being insulated completely-therefrom by insulating shell 42, and the portion of the wire 33' which passes through the shell being insulated therefrom by sleeve 43.

4 2,s1s,c1a

' said restraining means while allowing restricted have extensions 24' and 28' which serve to form a supporting member, as in the case oi! the single contact type of socket.

Fig. 19 shows the disposition of the various elements when the process of assembly illustrated in Figs. 16, 17 and 18 is completed.

Fig. 20 shows another method of forming the shell 42 of insulating material. A single flat strip of suitable insulating material, such as fibre, may be bent around until it assumes the form shown at 42', with overlapping ends 48, 48.

It is to be noted that insulating shell 2 extends forward sufdc'iently to protect the glass of an inserted bulb and prevent accidental contact with live contacts, and yet this shell is spaced from the glass sufliciently to allow for possible variations in the size or shape of bulb, which may occur.

While I have shown and described my socket as using a bayonet type lamp, lt will be evident that in place of the apertures 21, there may be formed internal threads upon the body 20, so that a screw type base lamp may be employed therewith, or by suitable modifications any-other suitable type of lamp base may be accommodated in my socket.

While I prefer to from the bulge 32 upon my eylot, so that the wire cannot come forward in the socket when the lamp is removed, and make an accidental short-circuit, yet it is possible to omit this particular element, together with its function, if so desired.

Structures made according to the present invention are cheap to manufacture, easily assembled at the spot where they are to be used, and when so assembled, are completely wired up and ready to be connected, thus saving the time and expense of wiring.

Due to the wire being doubly secured, by-the soldering of its bare end and by gripping of its insulation, great security against accidental dislodgement thereof is provided and the complete enclosure of all live parts of my sockets within an outer sheath likewise reduces the possibility of accidental short-circuitspractically zero.

The easy change of position afforded by my clamp allows various sizes and types of bulbs to be used in my sockets and allows these various bulbs tobe adjusted to give the desired illumination, without the need of tools, and by the layman.

Another advantage of this invention is that a unitary wire and contact structure can be supplied by the manufacturer ready to assemble in the radio receiver, thus reducing cost and simplifying assembly operations.

- A still further advantage of my structure over those of the prior art is that it is impossible for the contact of my socket to move outside of the protective outer shell and make accidental contact with other adjacent members of a radio receiver, as for example when a lamp has been removed from the socket and the socket slides upon its support.

I claim:

1. As a unitary article of manufacture, an electrical socket of the completely insulated twowire type, including a first hollow substantially cylindrical metallic shell, lamp connection means mounted within said first shell and including an insulating washer, means extending inwardly of said shell and restraining said washer in a lane substantially normal to the axis of said shell when no lamp is in the socket, a compression spring tending to hold said washer against longitudinal movement of the washer, a contact located upon said washer, means for retainin the base of an electric lamp within said shell, an insulating shell surrounding said metallic shell and provided with a longitudinally extending groove'for the reception therein of a connecting wire, a second metallic shell closely embracing said insulating shell and groove, and means for supporting said second metallic shell, whereby said first metallic shell and the elements enclosed therein are protected from accidental contact and are supported by said insuv lating shell and said second metallic shell.

2.'An electrical socket according to claim 1 in which the second metallic shell is additionally provided with inwardly biased spring ears, pressing against the insulating shell so as to hold all the socket elements in an integral structure, thereby preventing accidental displacement of said elements when a lamp is inserted in or withdrawn from the socket.

3. A lamp socket formed of a single strip of metal and having a resilient cylindrical lamp base receiving portion and a mounting portion, the latter portion comprising the two ends of the strip partially overlapping each other and together with parts adjacent the cylindrical portlon forming a channel for receiving a supporting member, the cylindrical portion having a bayonet slot at one end for receiving the locking pin of a lamp mounted in the cylindrical portion" and at the other end inwardly turned lugs, a sliding-contact-carrying disc mounted in the cylindrical portion, and a spring interposed between said lugs and said disc.

4. A double contact type socket comprising an outer cylindrical portion having overlapping tail pieces forming mounting means, an inner cylindrical portion for receiving a .lamp base, said inner portion having an inner contactdisc, a conducting wire connected to said disc, "a conducting wire connected to and extending along the side of the inner cylindrical portion and between portions of the tail pieces and an insulating sleeve between the innerand outer cylindrical portions and having a channel portion embracing part of the wire connected to the lug of the inner portion.

5. As an article of manufacture, a lamp socket including a one-piece substantially cylindrical metallic shell acting directly to hold and make contact with a lamp base and having formed integrally therewith a lateral extension in the form of a flattened tube adapted closely to hug and to slide over a flat supporting strip having a contour substantially identical with that of said tube, said flattened tube being expansible I simultaneously with the expansion of said cylin- J drical shell so as elastically to grip said fiat strip, said socket also including within said shell means for holding a lamp base and means for making electrical connections thereto whereby the position of said socket as a whole may be altered over a predetermined distance in 2. iongitudinal direction without affecting the holding of said lamp base therewithin and without atfecting the electrical connections to said lamp base.

- 6. As a unitary'article of manufacture, an electrical lamp socket including a metallic shell formed atleast in part as a laterally expansible tube, inwardly extending projections formed integrally with said shell near one end thereof and also at a point intermediate the ends thereof,

lamp connecting means including an insulating washer bearing a contact thereupon and having a diameter only slightly less than the interior diameter of said laterally expansible tube, whereby the washer can be pushed beyond said intermediate inwardly extending projections during assembly, by the lateral expansion of said shell, spring means pushing said washer against said intermediate projections and means for communicating the counterthrust of said spring means to said inwardly extending end projections, said socket also including a portion in the form ofa flattened tube capable of gripping and sliding upon a flat supporting strip.

'7. A lamp holder comprising an outer main split cylindrical sheet metal portion having two overlapping resilient end portions forming a flat- I tened tubular part capable of being slipped on to a flat support, said main portion having a contracted neck between the cylindrical portion and the flattened tubular part, a cylindrical inner metallic tube, a layer of insulating material between the inner metallic tube and the outer main split cylindrical sheet metal portion, said insulating material having a channel-like portion between the sides of the said contracted neck, a conductor extending through said channel-like portion and having one end secured'to the inner metallic tube and a spring-pressed contact mounted within said inner metallic tube.

M'ILTON ALDEN.

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