US 3148009 A
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P 4. A. ABRAMSON 3,148,009 COMBINATION PIN-TYPE LAMP AND INSULATION PIERCING ATTACHMENT SOCKET, CONSTRUCTION Filed Sept. 19, 1962 I A ll;-
United States Patent York Filed Sept. 19, 1962, Ser. No. 224,708 2 Claims. (Cl. 339-99) This invention relates to the stringing of electric lights on insulated dual conductor cord and more particularly is directed to improved incandescent lamp socket constructions of the insulation piercing type whereby strings of lights for use on Christmas trees or for other display purposes may be created on-the-spot or additional lights added to existing lighting outfits.
Among the objects of the invention is the general improvement of electric lamp sockets of the character described which shall comprise few and simple parts for economical manufacture in quantity production requiring a minimum of skilled labor in assembly, which sockets shall accommodate pin base lamps for rapid and easy replacement thereof and a simplified construction for attachment in electrical contact by insulation piercing to any desired point along dual conductor cord of conventional type, which sockets shall be foolproof in operation and rugged in construction to withstand intended rough usage including repeated mounting, removal and remounting, and which shall be practical and etricient to a high degree in use.
Other objects of the invention will in part be obvious and in part hereinafter pointed out.
The invention accordingly consists of features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter disclosed, the scope of the application of which will be indicated in the claims following.
In the accompanying drawing in which an illustrative embodiment of the invention is shown:
FIG. 1 is a perspective view of a socket and lamp constructed to embody the invention shown mounted on an insulated dual conductor cord.
FIG. 2 is a vertical sectional view taken substantially along line 22 in FIG. 1.
FIG. 3 is a vertical sectional view taken substantially along line 33 in FIG. 2.
FIG. 4 is an exploded view of the socket shown in FIG. 1 turned upside down with parts broken away and in section to show details of construction.
FIG. 5 is a bottom end view of the socket shown in FIG. 1 with the retaining cap removed showing the insulation piercing prongs, and
FIG. 6 is an enlarged perspective view of the combination pin receptacle and insulation piercing prong removed from the socket.
Referring in detail to the drawing, 10 generally denotes a pin base electric lamp and insulation tap-type socket assembly constructed to embody the invention comprising a lamp 11 having a pin-type base provided with a pair of terminal pins 11a extending through glass envelope 11b and telescopingly engaging a pair of pin receptacles 13:: each forming a part of a combination terminal fitting 13 of insulation tap-type socket 12.
Socket 1 2 is seen to comprise a body 14 seating lamp 11 on an upper end thereof and having a transverse passageway 12a adjacent a lower end through which dual conductor cord C extends for tapping electric current from the lead wires W through insulation I to energize lamp 11. A removable cap 15 forms a bottom closure for passageway 12a and is formed with a central boss 15a "Ice retaining insulation piercing prongs 13b of combination terminal fittings 13 in electrical contact with lead wires W.
Body 14 may be molded of any suitable resinous electrically non-conductive material seen in FIGS. 2, 3 and 4 to comprise an exterior wall 14a terminating in an inwardly beveled edge 14b and a transverse wall 140, the latter and wall 14a forming a seating chamber 14a for base 11c of lamp 11. A neck 14e extends from the underside of transverse wall providing shoulder 14 and has external threads 14g for engaging internal threads 15b of cap 15. A cut-out or deep groove 14h extends diametrically across neck 14e dividing the latter into two segments and extends a predetermined distance into transverse wall 140 beyond shoulder 14f to provide transverse passageway 12a for conductor cord C when cap 15 is fully threaded onto neck 142 with rim edge 15c abutting shoulder 14 A pair of spaced openings 141' extend through transverse wall 140 communicating chamber 14d with transverse passageway 12a. Openings 141' are properly spaced and centralized with respect to chamber 14d to register with lamp pins 11a when lamp 11 is properly seated in chamber 14d. As is clear from FIGS. 4 and 5, openings 14: each have a lateral slot 14k extending in opposite directions transversely with respect to passageway 12a and communicating with the latter. A tack receiving hole 14m is associated with each opening 14i, being spaced therefrom in opposite directions along the bottom of groove 14h.
Terminal fitting 13, which may be stamped and die formed as an integral unit from sheet metal, is seen in FIGS. 4, 5 and 6 to comprise a cylindrically shaped pin receptacle 13a terminating at one end in a gripper portion having longitudinal slits 13c forming resilient pinchers 13d which are formed with indentations 13c for frictionally gripping lamp pins 11a in the well understood manner. Extending laterally of and beyond the end of receptacle 13a opposite pinchers 13d is an integrally formed insulation piercing prong 13b which may be provided with a split point. Extending from the piercing prong end of receptacle 13a at right angles to prong 13b and to the longitudianl axis of receptacle 13a is a tab 13) for engaging under the head 16a of tack 16 pressed into hole 14m.
As an aid for guiding pins 11a into receptacles 13a and for providing a stop on which a lamp base rests for properly seatingin chamber 14d when lamps of different sizes and shapes, as for example, of cylindrical contour (not shown), are used in place of lamp 11, an upstanding diametrically extending ledge 1411 may be provided on transverse wall 140 between openings Hi.
The practical application of pin base electric lamp and insulation tap-type socket assembly 10 will now be apparent. After constructing the parts as above described and shown in the drawing, body 14 is assembled with terminal fittings 13 by inserting one of the latter into the bottom end of each opening 141', that is, into the end adjacent groove 14h so that pinchers 13d face chamber 14d and the lateral portion of insulation piercing prongs 13b seat in lateral slots 14k with tabs 13 extending in opposite directions along the bottom of groove 14h. Tacks 16 are then pressed into hole 14m so that the ends of tabs 13 extend beneath tack heads 16a to secure fittings 13 in position. Socket 12 is now ready for rapid mounting anywhere along a dual conductor cord C. This may be accomplished with minimum of effort and skill by inserting cord C into groove 14h so that both conductors lie fiat against the bottom with each of insulation piercing prongs 13b in register with one of the conductors as will be clear from FIGS. 2 and 5. Cap 15 is then threaded onto neck 14e whereby central boss 15a enters groove 1411. As cap 15 is tightened, central boss 15a acting as a pressure element is forced against conductor cord C causing insulation piercing prongs 13b to pierce insulation I and make positive electrical contact with lead wires W. Passageway 12a is formed at the bottom of groove 1411 when cap 15 is completely closed, that is, when its edge 15c abuts shoulder 14], passageway 12a being proportioned with respect to conductor cord C to receive the latter in a confined condition under pressure at opposite ends thereof by cap edge 15c and in the central portion by boss 15a, piercing prongs 13b extending well into passageway 12a to insure contact with wire W. Openings 141, being positioned along the longitudinal center line of groove 14h, and lateral slots 14k, extending in opposite directions on opposite sides of said center line, serve to locate each piercing prong 13b on one of the opposite sides of the center line. This lateral offset and longitudinal spacing of prongs 13b insures proper registry of each of the latter with just one of the strands of conductor cord C when the latter is placed fiat in groove 1472.
After socket 12 is mounted on conductor cord C lamp 11 is rapidly seated in chamber 14 by inserting pins 11a into receptacles 13a for frictional engagement therewith. When replacement of lamp 11 is required, as for example, due to burn out or when a change of the color of the lamp is desired, the rapid plug-in feature of pins 11a and receptacles 13a conserve considerable time and effort in making such changes and also avoid the necessity of checking the tightness of lamps which may appear faulty due to loosening as is often the case when using threaded type sockets.
A plurality or string of sockets 12 may thus be assembled at spaced distances along conductor cord C which may be terminated by suitable electric power circuit tapping means such as a conventional plug in the well understood manner to complete a portable display lighting outfit for Christmas trees or any other use, as for example, as described and shown in my Patent Number 2,864,070 patented December 9, 1958.
It is to be understood that body 14 may be suitably cut away and notched in the region of shoulder 14f and neck 14s to removably accommodate a support holder or clip for attaching socket 12 to a supporting structure such as a window or door frame as shown in my said patent or to a Christmas tree branch in the well known As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiment above set forth, it is to be understood that all matter herein set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.
Having thus described my invention, I claim as new and desire to secure by Letters Patent:
1. In combination, an electric lamp having a base with a pair of terminal pins, a socket for said lamp having receptacles for removably receiving said pins, said socket having a body molded of resinous electrically non-conductive material, the body having an open ended chamber for receiving said lamp base and a transverse wall forming a bottom of said chamber, an end of said body opposite said chamber being formed with a diametrically extendmg groove cutting a predetermined distance into said transverse wall, a length of insulated dual conductor cord extending through said groove and lying flat against the bottom thereof, a cap removably engaging said opposite body end closing said groove and retaining said dual conductor cord therein, a pair of spaced openings centralized to register with the lamp terminal pins and extending through said transverse wall communicating said chambers with said groove, each opening having a lateral slot extending in opposite directions transversely of said groove and communicating therewith, a terminal fitting including said terminal pin receptacle seated in each opening and having a laterally ofiset insulation piercing prong seated in said slot, said cap having a central boss extending into said groove urging the conductor cord against the groove bottom and retaining the cord in electrical contact with said prongs, and fastening means secured in said transverse wall retaining said terminal fittings in said openings and slots upon removal of said cap and disengagement of said conductor cord therefrom.
2. The combination defined in claim 1 in which each of said terminal fittings is integrally formed with said pin receptacle and insulation piercing prong and has an integrally formed tab extending along the bottom of said groove, said fastening means including a headed tack securing an end of said tab to the groove bottom.
References Cited in the file of this patent UNITED STATES PATENTS 1,887,784 Propp Nov. 15, 1932 2,491,463 Brooks Dec. 13, 1949 2,576,363 Rively et al. Nov. 27, 1951 2,657,367 Brooks Oct. 27, 1953 2,869,097 Stuart Jan. 13, 1959 2,941,181 Fraser et al. June 14, 1960 FOREIGN PATENTS 1,136,528 France Dec. 29, 1956