US2742620A

US2742620A - Compressible lampholder with torsion spring contacts for double ended discharge lamps

Info

Publication number: US2742620A
Application number: US543654A
Authority: US
Inventors: John M Pistey
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1955-10-31
Filing date: 1955-10-31
Publication date: 1956-04-17
Anticipated expiration: 1973-04-17

Description

April 1-7, 1956 PISTEY 2,742,620

COMPRESSIBLE LAMPHOLDER WITH TORSION SPRING CONTACTS FOR DOUBLE ENDED DISCHARGE LAMPS Filed Oct. 51, 1955 2 Sheets-Sheet l 3 f/71/e/7f0r: Job/7 M. P/SfQg fl s A'f/ok/zgg April 17, 1956 P|STEY 2,742,620

COMPRESSIBLE LAMPHOLDER WITH TORSION SPRING CONTACTS FOR DOUBLE ENDED DISCHARGE LAMPS Filed Oct. 31, 1955 2 Sheets-Sheet 2 fm/e/rfor: Job/7 M. p/sfgy A05 Affomg/ COMPRESSIBLE LAMPHOLDER WITH TORSION SPRING CONTACTS FOR DOUBLE ENDED DIS- CHARGE LAMPS Application October 31, 1955, Serial No. 543,654

' 8 Claims. (Cl. 339-50) The present invention relates to a stationary lampholder of a pair of lampholders for supporting double-ended electric discharge lamps of the fluorescent type having preheated electrodes mounted at the end of the tubular glass envelope. The lampholder of this invention is especially adapted to receive lamps equipped with bases of the type disclosed in the Lemmers Patent No. 2,716,739 which is assigned to the same assignee as is the present invention.

The novel lamp base of the Lemmers patent makes possible the utilization of the usual inlead wires of the lamp electrodes as the lamp terminals, thus eliminating the need for externally protruding contact pins. The inlead wires are recessed within an outwardly projecting electrically insulating part of the base to protect them from accidental contact.

This invention is likewise related to the applicants copending application, Serial No. 531,015, which was filed on August 29, 1955, and assigned to the same assignee as is the presentinvention. Fluorescent lamps are supported at each end by a lampholder, and the smaller the size of a lampholder from its lamp engaging face to, its

back face, the shorter the over-alldistance will be b'etween' the backs of the lampholders. Thus, in using the stationary lampholder embodying my invention, lamp fixtures for supporting thelamp may be reduced in length, thereby eifecting a cost saving for the lamp fixture manufacturer as well as making it possible to increase the illumination by installing more fixtures for a given ceiling length and reducing dark spots between the lamps.

The stationary lampholder embodying my invention comprises a thin base member with a shallow recess and a cover member which is fastened to the base to form a hollow housing. The cover has an oval shapedopening for receiving a lamp base with recessed terminals. The contacts of my lampholder are formed of torsion springs where the terminal end of each spring is fastened inthe housing for connection with a lead wire. The opposite end of each torsion spring has an offset arm which extends partially into the opening in the cover. A central projection is formed in the base toseparate the ofifset arms or" the contacts and to support and guide these arms with a pair of grooves formedon opposite sides of the projection.

Thus, the offset arms are arranged in a single plane to converge slightly toward each other outwardly of the lampholder. I

My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

Figure 1 is a side elevational view showing the novel stationary lampholder of the present invention supporting the right-hand side of a lamp in cooperation with a compressible lampholder at the other end.

Figure 2 is a view similar to that of Figure l with the lampholders shown in cross-section; the view of the lefthand lampholder being taken on the lines 2-2 of Figure 3 while the view of the right-hand lampholder of my invention is taken on the lines 3-3 of Figure 4.

.into the slots 23 of the base in a well-known manner.

Figure 3 is a front view of the left-hand lampholder' of Figure 2.

Figure 4 is a front view of the right-hand lampholder of Figure 2. v

Figure 5 is an end view of a lamp base with recessed terminals which is to be mounted in the lampholder embodying my invention.

Figure 6 is an exploded view of the left-hand lampholde'r of Figure 2.

Figure 7 is an exploded view of the righthand lampholder of Figure 2 which embodies my invention.

Referring in detail to the drawing and in particular to Figure 1, the lamp has a tubular glass envelope 10 provided with bases 11 and 12 attached to its ends, and is supported between a pair of

lampholders

13 and 14 which are to be attached to a suitable support which may be part of a lighting fixture. A compressible holder 13 is shown in cross-section at the left-hand side of Figure 2 as well as in the exploded view of Figure 6, while the stationary holder 14 is shown in cross-section at the right hand side of Figure 2 and in the exploded view of Figure 7. The parts which comprise the holder 13 may be best explained with reference to Figure 6 which shows a recessed base member 16 of suitable molding insulating material having an open end 17 for receiving an insulating cover 18 that is adapted tomove back and forth in the base. Four equally spaced notches 19 are located around the periphery of the cover to mate with four similar guide ribs 20 on the interior of the side walls of the base. A metal cup 21 fits over the main portion ofthe base 16 and is fastened therewith when the lanced tangs 22 spring inwardly directed flange 24 of the cup serves as a limit means to prevent the cover 13 from becoming separated from the base.

The front face of the cover 18 has a non-circular cavity- 25 for receiving the lamp base 11 of Figure 5. A central projection 26 is located in the cavity with a pair of opposite grooves 27 formed therein. A pair of contacts 30 are located behind the cover 18 and they each comprise a lamp terminal-engaging portion 31 and a spring seat 32 about which the contact fulcrums. A group of four coil springs are positioned in the base, two of which are current carrying such as springs 33 which engage the spring seats 32 of the contacts at one end and have a terminal hook 34 at the opposite end for making connection with a lead wire. The other pair of coil springs 35 are merely confined between the base and the cover to normally bias the cover against the flange 24 of the cup member.

The lamp bases 11 and '12 are identical so that reference will be made to only base 11 of Figures 2 and 5. This base comprises an annular metal shell -42 and a disk 43 of electrically insulating material, such as an organic plastic. embedded in the periphery of the disk 43 to mechanically join these elements together as shown in Figure 2. The base 11 is secured to the end of the glass envelope 19 by a body of basing cement 44. The disk 43 has an ovalshaped embossment 45 which is to be fitted into the cavity 25 in the front face of the cover 18. passage 46 extends completely through the disk so that the wire inleads 47 and 48 connected to electrode 49 of the lamp may be brought outwardly to constitute recessed electric terminals for the lamp. Attention is specifically directed to the fact that in both Figures 2 and 5 the

terminals

47 and 48 are shown as being set into recessed notches 50 in the embossment 45. Likewise, slots 51 are formed in the periphery of the embossment and they communhv cate with the notches 50 to enable the contacts of my Patented: Apr. 17, 1956 Art The inner rim of the shell 42 is that a minimum thickness of lampholder can be obtained as will be better understoodhereinafterv The assembly of the lamp in the compressible lampholder 13 may be best explained with reference to Figure Z Where the embossrnent 45 of the lamp base is inserted in the cavity 25 of the cover 18 As a pushing force is exerted on the lamp the cover 18 willmove against the

springs

33 and 35 and the contacts 30"w ill be engaged by the recessed terminals 47 and:48. of the lamp base. It is clear that thecontacts 30would tend to fulcrum about their spring seats into the housing of the lampholder with the result that there is both a longitudinal and a transverse forcc'exertcd on the terminals of the lampbase, it beingunderstood that the word longitudinaF means longitudinally of the lamp,

Having described above the construction of a compressible lampholder with which the stationary lampholder of my invention is to be used, I will now refer to Figure 7 fora detailed discussion of the manner in which I use torsion springsprings for the contacts of a stationary lampholder for receiving a lamp base with recessed terminals. The stationary lampholder 14 of Figure 7 has a recessed base 55 of molded phenolic orother suitable electrical insulating material and an insulating cover 56 fastened by screw means 57 over the face of the base.- The cover 56 is somewhat different'frorn that of cover 18 of Figure 6 because of the oval-shaped opening 58 extending completely through the cover for receiving a lamp base with recessed terminals.

The contacts are shown as identical torsion springs 59 comprising aterminal end 60 which is adapted to lie on the-floor of the base 55 for connection with a lead wire (not shown). has an offset arm 61 which extends partially into the opening 58. An insulatingprojection 62 is mounted in the base to separate the oflset arms 61 of the contacts and to guide and support them by means of a pair of opposite grooves 63 as is best shown in Figure 2. it will be noticed that the end of the projection63 does not extend out of the opening 58 in the cover so that it is slightly depressed within the holder. The subject lampholders are so designed that it is not possible for a persons finger to extend into the lampholder and touch both of the contacts at the same time. safety feature contained in a lamp with recessed terminals has been carried into the lampholders so that it is practically impossible for anyone to receive an electrical shock from the contacts or terminals of this lamp assembly. Also, it will be clear that the oflset arms 61 of Figure 2 are moved against the action of the spring when the lamp base is inserted in the housing which will provide a force against the lamp terminals that is both longitudinal of the lamp as well as transverse of the lamp so that a double wiping action is made with the lamp terminals.

Modifications of this invention will occur to those skilled in this art and it is to be understood, therefore, that this invention is not limited to the particular embodiment disclosed but that it is intended to cover all modifications which are within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A stationary fluorescent lampholder comprising a hollow housing having a recessed base and a cover member, said cover member having a central opening for receiving a lamp base with recessed terminals, a central projection formed on the base to extend into the cavity, and a pair of torsion spring contacts positioned in the housing, the terminal end of each spring being held fixed by the cover for connection with a leadwvire, the opposite end of each spring being formed with an offset arm that is generally parallel with the side of the said projection-and adapted to make connection with the recessed terminals of'a lamp;

The opposite end of the spring Hence, the

2. A fluorescent lampholder of minimum depth comprising a hollow housing with a recessed base and a cover member, an opening formed in the cover for receiving a lamp base with recessed terminals, and a pair of torsion springs positioned in the housing, the terminal end of each spring being held fixed by the cover for connection with a lead wire, the opposite end of each spring being formed with an ofiset arm which represents a contact of a pair of similar contacts converging outwardly of the lampholder, and a projection formed on the said base between the contact ends of the torsion springs, and a groove formed on opposite sides of the projection for receiving the offset arms of the contacts therein.

3. A stationary fluorescent lampholder comprising a hollow housing of insulating material having a shallow recessed base and a cover member, said cover member having an oval-shaped opening for receiving a lamp base with recessed terminals, a central projection depressed within the said opening, and a pair of torsion spring contacts fixed at their terminal ends in the housing while the opposite end of each spring, has an offset arm that is separated from each other by the said projection, and a pair of grooves formed on opposite sides of the projection to support and guide the movement of the ofiset arms when they are engaged by the recessed terminals of a lamp.

4. A stationary fluorescent lampholder of minimum depth comprising a hollow housingwith a shallow recessed base and a cover member, an oval-shaped opening formed through the cover for receiving a lamp base with recessed terminals, a pair of torsion spring, contacts with the terminal end of each spring being adapted for connection with a lead Wire, the free end of each spring having a cam-shaped offset arm for cooperation with the terminals of a'lamp, and a projection extending from the base partially into the oval-shaped opening of the cover between the contacts with the ofiset arms being supported and guided in opposite grooves in the projection in a single plane that is generally perpendicular to the supporting surface of the base.

5. A stationary fluorescent lampholder as recited in claim 4 wherein the said projection of the base extends beyond the free ends of the contacts to reduce the danger of electric'shock.

6. A fluorescent lampholder comprising a hollow housing of insulating material, the front face of the housing having an opening for receiving a lamp base with recessed terminals, a central projection formed in the opening of the housing, a pair of torsion spring contacts positioned in the housing, the terminal end of each spring being held fixed in the housing for connection with a lead wire, the opposite end of each spring having an offset arm that is generally parallel with the side of the saidprojeetion and adapted to make connection with the recessed terminals of a lamp.

7. A lampholder as recited in claim 6 wherein there is a groove on opposite sides of the projection to support and guide the movement of the offset arms of the springs when they are engaged by the recessed terminals of a lamp.

8. A lampholder as recited in claim 7 wherein the offset arms of the spring contacts converge outwardly of the housing with each having a rounded tip so that when a lamp is inserted into the lampholder the springs will be flexed slightly to move the offset arms toward each other and provide a wiping engagement with the terminals of a lamp.

References Cited in the file of thispatent UNITED STATES PATENTS 1,717,762. Davis June-18, 1929 1,980,187 Crawford Nov. 13, 1934