US 3430189 A
Description (OCR text may contain errors)
e 25, 9 w. B. LANDGRAF 3,430,139
RECESSED DOUBLE CONTACT PIN BASE Filed May 15, 1967 hwvervtov: WiLLiam B. Landgva' f ba @425 His A t to neg United States Patent York Filed May 15, 1967, Ser. No. 638,398 US. Cl. 339-14 5 7 Claims Int. Cl. H011 33/74, 9/08, 5/04 ABSTRACT OF THE DISCLOSURE An electric lamp base has a disk-shaped insulating body provided with a hollow embossment and a pair of spaced apart, inlead wire accommodating, hollow contact pins staked to and recessed within the embossed portion of the insulating body. Each pin has at its outer end an eyelet for connection to an inlead wire threaded through the pin, a rectangular portion in cross section extending longitudinally from said eyelet and, prior to being staked on the insulating body, a deformable tubular portion extending longitudinally from the rectangular portion and terminating in an open dome-shaped end. The rectangular portion of each pin is supported on three sides by the embossment, the fourth side being exposed within embossment for engagement with a lamp holder contact.
BACKGROUND OF THE INVENTION Field of the invention Bases having contacts recessed within an embossed, disk-shaped insulating body for safety purposes have been in extensive use for more than ten years on double-ended electric lamps, such as tubular fluorescent discharge lamps, of the type having preheatable electrodes mounted at the ends of a tubular glass envelope and a pair of spaced-apart current inlead wires for each of the electrodes extending from the ends of the envelope.
Description of the prior art Heretofore, the current inlead wires extending from the ends of the lamp envelope have been recessed and exposed within the hollow embossment of the insulating base body for utilization as the lamp terminals or contacts. Also, contacts welded to the inlead wires and in the form of strips of various configurations have been used similarly. Outwardly projecting exposed contact pins on the lamp bases thus were eliminated.
Fluorescent electric discharge lamps having bases provided with terminals or contacts of the above type are disclosed in US. Patents 2,716,739, Lemmers; 2,733,420, Marz; 2,733,421, Grovemiller; and 2,922,137, Krupp et al.
In the mass production of lamps equipped with such bases, properly inserting, orienting and afiixing the contacts in the insulating body of the base has been accomplished with some difficulty. If the contacts are misplaced, become loosened or displaced during manufacture or use of the based lamp to the extent that the base contacts fail to engage the lamp holder contacts, the lamp fails to operate. 7
SUMMARY OF THE INVENTION The principal object of the invention is to provide a lamp base of the above type readily manufactured at minimum cost including novel contacts which are easily I 3,430,189 Patented Feb. 25, 1969 mounted and firmly supported in proper position for effective engagement with electric socket or lamp holder contacts. The invention attains its object by utilizing as the contacts a pair of hollow pins which in part are rectangular in cross section and fit into cavities within the hollow embossment with one side of the rectangular portion exposed for engagement with a lamp holder contact. Each pin has a tubular portion for insertion into an opening in a wall at the bottom of the hollow embossment for staking the pin to the wall and an eyelet at its outer end for connection to a lamp inlead wire threaded through the pin aind welded or soldered to the eyelet.
BRIEF DESCRIPTION OF THE DRAWING In the drawing accompanying and forming part of this specification, an embodiment of the invention is shown in which:
FIG. 1 is a side elevational view of a double-ended electric discharge lamp provided with bases embodying the invention;
FIG. 2 is a fragmentary sectional view of an enlarged scale of one end of the based lamp shown in FIG. 1;
FIG. 3 is a plan view of the base shown in FIG. 2 as seen from the inner end of the base facing the end of the lamp envelope;
FIG. 4 is a similar view of the base shown in FIGS. 2 and 3 as seen from the outer end of the base;
FIG. 5 is a view similar to FIG. 4 showing a fragment of the insulating part of the base with the contact pins removed to show the internal structure of this part of the base; and
FIG. 6 is an isometric view on an enlarged scale of one of the hollow metal contact pins of the base embodying the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 of the drawing in which like numbers denote like parts in all the figures, the double-ended fluorescent electric discharge lamp comprises a tubular sealed glass envelope 1 provided with bases 2 and 3 attached to its ends. The bases 2 and 3 are of identical structure and the parts only of the base 3 have been shown in FIGS. 2 to 6 for conciseness in description.
The base 3 comprises an annular metal shell 4 which is suitably made of sheet aluminum and a body member of electrically insulating material, such as an organic plas tic, in the form of an embossed disk 5. The disk 5 may be made of commercial plastic molding compounds, such as those comprising phenol-furfural resins or phenolic resins. The inner rim of the shell 4 is embedded in the periphery of the insulating disk 5 to mechanically join these base members as shown in FIGS. 2 to 4. The base is secured to the end of the glass envelope by a body of basing cement 6.
The disk 5 has a raised elongated embossment 7 fiattened in cross section, extending across its center and projecting outwardly from the base (FIGS. 1, 2, 4 and 5) for engagement with a holder (not shown) for the lamp. The embossment 7 has straight parallel sides and rounded ends in cross section (FIGS. 4 and 5). The em bossment 7 is hollow and defines an inwardly extending slot 8 terminating at the wall 9 provided with a pair of openings 10 and 11. The slot 8 conforms generally t the cross sectional shape of the embossment 7, accommodates the electrical contacts of the lamp holder (not shown) and has recesses 12 and 13 at its opposite ends accommodating the rectangular portions 14 and 15 of the hollow contact pins 16 and 17, respectively. One side of the portions 14 and 15 of the pins is exposed within the slot 8 for engagement with a lamp holder contact.
The hollow contact pins 16 and 17 are aflixed to the embossed disk as described below and define wiring passages through which the inlead wires 18 and 19, respectively, of the lamp are threaded during lamp manufacture. The inlead wires 18 and 19 are electrically connected to opposite ends of the preheatable electrode 20 and extend through the press 21 of the stem 22 of the lamp envelope 1. In the completed lamp the wires 18 and 19 extend through the pins 16 and 17 of the base 3, as shown in FIG. 2, and are electrically connected by soldering or welding to the integral eyelets 23 at the outer ends of the pins 16 and 17.
As shown in FIGS. 2, 4 and 5, three sides of the rectangular portions 14 and 15 of the pins 16 and 17 make a close fit with the walls of the recesses 12 and 13, respectively, in opposite ends of the slot 8 in the embossment 7. This provides firm support against forces tendlng to rotate the pins 16 and 17 axially or to move the rectangular portions 14 and 15 away from each other laterally as the contact pins are engaged with or disengaged from the spring-mounted contacts of a conventional lamp holder.
As shown in FIGS. 2, 3 and 5 of the drawing, the pins 16 and 17 are affixed to the disk 5 by their tubular portions 24 which, in the manufacture of the base, are first passed through the slot 8 and inserted into the openings and 11 of the wall 9 and then upset against the wall 9 to hold the inner end of the rectangular portions 14 and of the pins 16 and 17 firmly against the opposite side of the wall 9. The tubular portions of the contact pins 16 and 17 have an opening 25 at thelr outer ends to facilitate the cutting and spreading thereof in the form shown at 26 in FIG. 3. This is conventional and a well known operation in the lamp base making art. With the pins 16 and 17 affixed to the base in this manner the eyelets 23 at the outer ends of the pins are recessed within the outer end of the slot 8 as shown in FIG. 2. The width of the slot 8 is such that the eyelets cannot be touched when mounting the lamp in lamp holders. As shown in FIGS. 2 and 4, the outer ends of the pins and the surfaces of the rectangular portions 14 and 15 thereof exposed within the slot 8 are readily accessible for engagement with contacts of the lamp holder in the usual manner.
The inlead wires 18 and 19 extending from the ends of the lamp envelope 1 are easily threaded into the hollow pins 16 and 17 of the bases 2 and 3 for connect on by soldering or welding to the eyelets 23 to facilitate the manufacture of the lamp. Reference is made to US. Patent 2,892,923, R. A. Kuebler, for a disclosure of a method and apparatus useful in Welding the ends of the inlead wires to the eyelet of each contact pin.
The exposed longitudinally extending surfaces of the rectangular portions 14 of the pins and the eyelet ends of the pins provide contact surfaces of large area for engagement by the lamp holder contacts which are accommodated within the slot 8 when the lamp 1 is mounted in the conventional lamp holders. I
The sides of the rectangular portions 14 of the plus are larger in width than the outer diameter of the tubular portions 24 thereof so that the shoulder 27 is provided on the pins for engaging the Wall 9 as shown in FIG. 2.
The pins may be made in the shape described above by folding a suitable blank cut from a metal strip, brass for example, around a mandrel into the form shown in FIG.
The disk 5 has a vent 28 in the wall 9 for fluids resulting from curing of the basing cement 6. The vent 28 flares outwardly toward the back of the base to assure adequate spacing between the exhaust tip 29 of the lamp envelope 1 and the base mounted on the envelope.
While a preferred species of the invention has been disclosed, it will be understood that such disclosure is for illustrative purposes and that it is contemplated that changes may be made in the form and details of the base without departing from the invention as defined in the appended claims.
What I claim as new and desire to secure by Letters Patent of the United States is:
1. A base for attachment to an electric lamp envelope having a pair of outwardly extending inlead wires, said base comprising an electrically insulating body member in the form of a disk having an elongated hollow embossment flattened in cross section and extending outward from the "base for engagement with a lamp holder, said embossment having a lamp holder contact-receiving outwardly opening slot conforming generally to the shape of the embossment and provided with base contact receiving recesses at its opposite ends, said body member having an apertured wall at the bottom of the slot, said base comprising also a pair of hollow contacts for connection to said inlead wires, said hollow contacts being laterally recessed within the ends of the embossment, affixed to the apertured wall and fitting into the recesses at the ends of the slot with a lateral side thereof exposed for engagement with lamp holder contacts.
2. A base according to claim 1 wherein the exposed side of the hollow contacts presents a flat surface of substantial area for engagement with lamp holder contacts.
3. A base according to claim 1 wherein the recess fitting portion of the hollow contacts is rectangular in cross section.
4. A base according to claim 1 wherein the hollow contacts have at their outer ends an inlead wire-accommodating eyelet and define a wiring pasage into the eyelet opening.
5. A base according to claim 1 wherein the hollow contacts are staked to the apertured wall with the recess fitting portion thereof engaging the surface of the wall facing the slot.
6. A base for attachment to an electric lamp envelope having a pair of outwardly extending inlead wires, said base comprising an electrically insulating body member in the form of a disk having an elongated hollow embossment flattened in cross section and extending outward from the base for engagement with a lamp holder, said embossment having a lamp holder contact receiving outwardly opening slot conforming generally to the shape of the embossment and provided with base contact receiving recesses at its opposite ends, said body member having an apertured wall at the bottom of the slot, said base comprising also a pair of hollow contacts for connection to said inlead wires, said hollow contacts being laterally recessed within the ends of the embossment, each of said hollow contacts being in the form of a hollow pin having at its outer end an inlead Wire accommodating eyelet, a portion rectangular in cross section extending longitudinally from the eyelet and fitting into the recesses at the ends of the slot with a lateral side thereof exposed for engagement with lamp holder contacts, a deformable tubular portion extending longitudinally from the rectangular portion and defining therewith a wiring passage into the eyelet opening, said deformable tubular portion extending in part through an opening in the apertured wall and being upset in part against the surface of the wall facing away from the slot, the rectangular portion of the pin engaging the surface of the apertured wall facing the slot.
7. A hollow contact pin having at one end an inlead Wire-accommodating eyelet, a socket-contact engaging ortion rectangular in cross section extending longitudinally from the eyelet and a deformable tubular portion extending longitudinally from the rectangular portion and defining therewith a wiring passage into the eyelet opening, the sides of the rectangular portion being larger in width than the outer diameter of the tubular portion to 5 provide between said portions 21 support engaging shoulder.
References Cited UNITED STATES PATENTS 1,559,683 11/1925 Douglas 339220 1,888,165 11/1932 Gagnon 339--195 2,438,075 3/1948 Smith 339-220 Orr 339-145 Schwarz 339- 220 X Thomas 339-145 Pechy 339--145 U.S. C1. X.R.