US1957708A - Mechanical base - Google Patents

Description

May 8, 1934- Dfs. GUsTlN ET AL 1,957,708

MECHANICAL BASE Filed April 24, 1931 l INVENTORS a5. G05 r//v A. B

SATES OFFICE MECHANICAL BASE Application April 24,

6 Claims.

This invention relates to electrical devices such as incandescent electric lamps and relates more particularly to an improved base portion therefor.

5 In the manufacture of certain electrical devices such as incandescent electric lamps it is practice to provide the lamp with the base in the form of a metallic shell, or cap having one end open to receive a glass bulb. Usually the shells l or caps are threaded and are provided with a central contact supported in the bottom of the shell by an insulative ring. The shells, however, may be plain and provided with bayonet pins or they may have entirely smooth surfaces as when l used as a base for a lamp to be adjusted in another portion or socket, when the lamp is of such character that the lament is to be positioned in definite relation to the base portion in lamps termed precision lamps.

$0 The usual type of lamp base is, however, comprised of a threaded metallic shell which is secured to a lamp bulb neck by means of a suitable adhesive material which cements the bulb and base together. The use of a cementitious maa5 terial to attach the base to the bulb is extensively used in the practice of making incandescent lamps and obviously necessitates relatively expensive operations and since it is necessary to bake the adhesive material to set or dehydrate it 3o the operation of passing the bulbs and bases through a heating oven is also involved.

It is an object of the present invention to provide an incandescent lamp bulb having the base attached thereto in a firm and practical manner without the use of an intermediate cementitious material.

Another object of the invention is to provide a base mechanically secured to a bulb neck.

Anotherobject of the invention is to provide a 4@ base for the bulb of an electrical device which may include a plurality of elements operating to mechanically grip the base and cooperating with each other to retain the base relatively immovable on the bulb neck.

It has heretofore been proposed to mechanically apply a base to a bulb, as for example, Patent Number 1,813,572 issued July '7, 1931, for Lamp base is assigned to the assignee of the present invention, a structure is shown wherein an angular collar is provided to grip the bulb neck and a metallic shell embraces the collar thereby holding it in place, the collar and the shell being securely connected to provide a mechanically attached base.

'Ihe present invention utilizes a construction 1931, Serial No. 532,394

wherein a collar is initially attached to a bulb vneck by means of indentations in the collar which indentations register or conform in shape with and are disposed in dimples or depressions in the bulb neck. The collar is in the form of a split ring or collar serving as a retainer band and a cylindrical metallic base shell is so disposed about the collar as to rmly press the indentations into the depressions of the bulb neck. When so positioned the portions of the surface of the shell above the indentations of the collar are deformed by spinning or are otherwise pressed inwardly to provide indentations in the shell to t and fully occupy the indentations in the collar.

It has been found that in order to practice the formation of indentations in the shell, it is preferable to provide a perforation which subsequently constitutes the center of each of the indentations in the shell.

This perforation facilitates the spinning operation allowing the metal to. flow or expand so that the indentations formed in the shell may be rmly pressed i-nto the concave portions of the indentations of the collar.

By this method the outer shell is secured to the collar in such manner that all lost motion is prevented by reason of the exact fit attained as a result of the disposition of portions of the shell in firm contact with the indentations of the collar and since by this method it is possible to cause portions of the metal of the shell to firmly engage the entire concave surfaces of the collar, the collar will not only be forced tightly into position for engaging the bulb neck but the metal pressed from the shell will so completely occupy the concave depressions in the collar that no appreciable or detrimental relative movement between the collar and shell or the collar and bulb will be possible.

This feature is of extreme importance in connection with mechanically based lamps since it will be appreciated that ordinarily when connecting a lamp base to a bulb neck it is difficult owing to physical irregularities to provide a structure wherein the several component parts fit with such degree of accuracy as to avoid slight relative movement particularly where the parts are shaped separately and then fitted, whereby slight differences in dimensions often result in looseness between the parts when they are assembled. Slight movement of the cooperating elements which secure a base to a bulb may not be sufficient to make the device inoperative but in the manufacture of incandescent lamps where a rigid standard of manufacture is called for and particularly in an electrical device which must be made in large quantities and handled by inexperienced customers, any play in the parts or any looseness which might eventually cause the connected leading in conductors to separate, offers disadvantages which the manufacturer seeks to avoid.

Furthermore the mechanical base must be of such construction as to be readily assembled and attachable to the base in such manner as to successfully compete with the cemented base both in cost of the respective parts and in the consumption of time necessary to complete the assembly operation.

The present construction for mechanically attaching a base of a lamp bulb will be more clearly understood from the following description together with the accompanying drawing, in which Fig. 1 is a side view of an ordinary incandescent electric lamp having a base attached thereto in accordance with the present invention.

Fig. 2 is an enlarged vertical cross sectional view of a bulb neck showing the present mechanical base applied thereto.

Fig. 3 is an enlarged view taken on lines III-III in Fig. 2 and Fig. 4 is a view showing the bulb neck, collar and base in perspective and separated prior to assembly.

Although the present invention may be applied to various types of electrical devices employing a bulb it is shown and described in connection with an incandescent electric lamp comprising a bulb 10 having a lament 1l mounted on support wires l2 projecting from an arbor 13 extending from a flare tube 14 which may be sealed to the bulb in the usual manner. Lead wires 14 and 15' are connected to the terminals of the iilament and extend downwardly into the base.

The bulb 10 is provided with a neck portion 15 which may be shaped by heating to provide cylindrical surfaces 16 and 17 and a shoulder 18. The surface 17 is provided with a plurality of dimples or depressions 19 preferably three depressions are provided in equal space relation.

The base assembly to be attached to the bulb neck may comprise a split collar 21 and a metallic shell 22. The shell 22 as shown is provided with the usual threads 23 and a central contact 24 which is insulated from the shell by the usual .glass web 25.

Although the shell illustrated is provided with threads it will be understood that it may be of plain cylindrical form as for example when used as a bayonet type of base or as part of the structure employed in making certain types of precision lamps. The collar or retainer band 21 may be shaped -with cylindrical surfaces 26 and 27 of different diametrical dimensions to provide a seat 28 and the dimensions of the interior cylindrical surfaces maybe such as to fit the surfaces 16 and 17 of the formed bulb neck with the seat 28 engaged with the shoulder 18 when assembled. The surface 27 of the collar is provided with indentations 29 in spaced relation and of a number equal -to the depressions 19 so that when the collar is in place upon the bulb neck the depressions will receive the convex portions of the depressions 29. The collar 27 being split at 31 is arranged to tensionally engage the bulb neck and hold the indentations 29 firmly in the depressions 19. When the collar 21 is so positioned the metallic shell 22 is moved to surround the collar and is of such dimensions as to snugly flt the same,

The shell 22 is provided with three apertures or perforations 32 arranged to register with the indentations 29 so as to position one of the perforations over .each of the indentations.

The metal around the perforations is then depressed inwardly by forcing with a suitable tool or by spinning so that the entire inner surface 33 of the deformed portions of tlie shell are disposed in rm contact with the surfaces of the depressions 19.

As clearly shown in Fig. 3 the foregoing method makes it possible to secure the shell to the collar in such manner as to prevent any play or lost motion and the formation of depressions 34 resulting from the spinning operation causes the several layersof metallic material comprising the shell and the collar to intimately engage each other and at the same time the collar is firmly secured to the bulb neck.

Although the perforations 32 are desirable and facilitate the formation of the depressions 34 it is to be understood that these perforations may be dispensed with where the metal is soft or suiiiciently malleable to be distorted by a forming tool applied to the outer surface of the metallic shell. The perforations, however, allow for the expansion of the metal as it is distorted and in practice it has been found that these perforations make it possible to obtain the desired intimate relation between the depressions in the shell and the indentations in the collar. As illustrated the lead wire 14 may be soldered or otherwise secured to the contact 24 and the lead wire 15 may be disposed in a notch 30 in the edge of the base and may be soldered or otherwise secured at 35 to 110 the shell 22. I

For the purpose of allowing for the thickness of the lead wire 15 the bulb neck may be formed with a slot 36 to receive a portion of the lead wire 15' so that the collar 21 will fit the formed neck 115 and enclose a portion of the said lead wire between the bulb neck and the shell.

In making a base in accordance with the present invention for application to the bulb neck of the usual standard incandescent lamp, it is desirable to first shape the bulb neck byrst directing fires against the neck portion disposed adjacent to the flange of the iiare tube in such manner that the bulb neck and flare are sealed without thinning the glass above the point of consolidation.

The' -method of so forming the neck during sealing-in is clearly shown in copending application Serial No. 417,106 filed December 28, 1929 by D. S. Gustin for Method of sealing in, which application is assigned to the assignee of the pres- 1m ent invention.

By this method a relatively large mass of glass is left in the neck after the waste portion or cullet is cut off. The neck is then enclosed in a mold and air under pressure is introduced into the bulb to force the plastic glass against the mold so that it will take the required shape. The mold may then be removed and annealing fires applied to the molded portion to remove strains.

The cullet which is still connected by a thin wall of glass to the molded portion is then cut off and a further annealing operation is performed.

The present invention provides a simple and practical method of mechanically basing a lamp wherein the several parts may be readily assembled and secured with the necessary degree of accuracy to provide a base relatively free from looseness and having the ruggedness necessary for a device of the present character.

,Although a preferred embodiment of the invention is shown and described herein, it is to be understood that modifications may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

l. An electrical device comprising a bulb having a plurality of indentations in the neck thereof, a band surrounding said neck, raised bosses on said band engageable with said indentations to secure said band to said neck and a base having bosses disposed in nested relation with the bosses on said band.

2. An incandescent electric lamp comprising a bulb having lead wires extending therefrom, the neck portion of said bulb having a plurality of depressions, a resilient band fitted to said neck portion, a plurality of inwardly projecting cupshaped bosses formed from the wall of said band and disposed in said depressions, a shell having a contact connected to a lead wire, a portion of said shell being arranged to t over said band, the inside diameter of said portion being slightly greater than the outside diameter of the band when the bosses thereof are firmly disposed in said depressions, said shell having inwardly projecting portions formed to nest in the concave surfaces of said cup-shaped bosses.

3. An electrical vacuum device comprising a bulb having a neck portion formed with a plurality of depressions, a split band surrounding said neck, indentations on said band and arranged for disposition in said depressions, a metallic shell contact member for said device, said shell having an inside diameter slightly greater than the outside diameter of said band when the band is disposed with the indentations thereof in rm contact with the surfaces of said depressions, said shell having portions pressed into' intimate contact with the surfaces of said indentations to secure the shell and band to said bulb neck.

4. An electrical vacuum device comprising a bulb having a cylindrical neck portion, said neck portion having al plurality of depressions formed in the surface thereof, a retainer band surrounding said neck, said band having indentations to enter said depressions, a metallic shell Contact member for said device, said shell having a portion surrounding said retainer band and of slightly greater internal diameter than the outside diameter of said band when enclosed by said shell portion, said shell having portions formed to provide surfaces to press against the surfaces of said indentations to firmly hold the band and shell against relative movement on said neck portion. 5. An electrical vacuum device comprising a vitreous container having a cylindrical neck portion, said neck portion having depressions formed in the surface thereof, a retainer band surrounding said neck portion, a metallic shell contact member having a portion surrounding said band and of an internal diameter slightly greater than the external diameter of said band when surrounded by said shell portion and portions of said shell opposite to said depressions formed to provide inwardly extending bosses disposed in contact with the concave surfaces of said depressions.

6. An electrical vacuum device comprising a bulb having a cylindrical neck portion, said neck portion having depressions formed in the surface thereof, a retainer band surrounding said neck portion, said band having indentations disposed in said depressions, a base for said device having a cylindrical portion surrounding said retainer band and having an inside diameter slightly greater than the outside diameter of said band when the band is disposed about said neck portion, perforate portions disposed over said indentations, the metal surrounding said perforations being disposed in contact with the surfaces of said indentations.

DANIEL S. GUSTIN. ALFRED BONNEY, JR. CHRISTIAN FLEISCHMANN.

Images