US2454326A

US2454326A - Base and contact for electrical devices

Info

Publication number: US2454326A
Application number: US516014A
Authority: US
Inventors: Makenny William
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1943-12-29
Filing date: 1943-12-29
Publication date: 1948-11-23
Anticipated expiration: 1965-11-23

Description

Nov. 23, 1948.

w. MAKENNY BASE AND CONTACT FOR ELECTRICAL DEVICES 2 Shuts-Shoot 1 Filed Dec. 29, 1943 INVENTOR I, If) A's/10y BY m ATTORNEY Nov 23, 1948:

BASE AND CONTACT FOR BLBTRICAL DEVICES Filed Dec. 29 1943 2 Sheets-Shoot 2 "Wmm ATTORNEY w. IMAKENNY 2,454,326 I Patented Nov. 23, 1948 BASE AND CONTACT FOR ELECTRICAL DEVICES William Makenny,

Mountainview, N. 1., we to Westinghouse Electric Corporation, East llttshurgh, 2a., a corporation of Pennsylvania Application Deumber 29, 1943, 861181 No. 510,014

comma (c1. ll3- 361) This invention relates to bases for electrical devices, and more particularly to such adapted for fluorescent lamps.

The principal object of myinvention, gener ally considered, is to provide a pin for a pressed base and of such a formation, as compared with that of the base, that it holds tightly in place.

Another object of my invention is to provide a pin, preferably'i'ormed of. brass, with a, hollow collar relatively long axially and disposed intermediate its ends, that portion of 'said pin on one side of said collar preferably being relatively long and generally cylindrical to form'the outer contact element, and that on the-other side being shorter and'tapered for part or its length from a diameter larger than that of said cylindrical portion to one corresponding therewith, and then continuing generally cylindrical to near the end, whereby itmay be staked in a base of phenolformaldehyde or thermosetting resin or other base material and provide a secure and lasting connection therewith.

A further object of my invention is to provide a base of Bakelite, glass or other suitable material formed with contact pins as above described held tightly in place by radial as well as axial stress.

A still further object of my invention is the provision of a method of staking or connecting contact pins as above described to bases. comprising inserting such pins in a lower die, fitting a base thereover, forcing tions of said pins by means of a spring plunger, prestaking the pins with apyramidal tool to cut and expand their upper ends, partially collapsing the hollow collar thereof, and finally staking the pins with a cylindrical tool to crimp the expanded end portions of the pins over the base bottom wall and further collapse the collar, resulting in a tight fit therebetween due to radial stress of the tapered or frusto-conical portion of the pin in the base aperture, in addition to the axial stress caused by the staking tool.

the base over the tapered por- Other objects and advantages of the invention,

relating to the particular arrangement and construction of the various parts, will become apparent as the description proceeds.

Referring to the drawings which show to scale only one embodiment of my invention:

' Figure l is a fragmentary side elevational view, full size in the original drawing, of a discharge device embodying my invention.

Figure 2 is a fragmentary elevational view, full. size in the original drawing, with parts in vertical section, of astaking machine embodying my invention.

- after a. plunger has Figure 3 is a diagrammatic plan view or a stak ing machine shown in Fig. 2, reduced in scale.

Figure 4 is an axial sectional view, full size in the original drawing, with the base pins in elevation, of a base after such pins have been completely staked in place.

Figure 5 is an enlargedaxial sectional view of a pin embodying my invention,and in position for connection with a base.

Figure 6 is a view corresponding to Fig. 5, but showing the position of the parts when the base has first been fltted over said pin.

Figure '1 is a view corresponding to Fig. 6 but showing the next; position of the parts, that is, forced the base down over the top portion 0! the pin so that it tightly grips the tapered or frusto-conical portion thereof.

Figure 8 is a view corresponding to Fig. 7, but showing the next position where the pre-staking pyramidal tool has engaged the upper portion of the pin and cut and expanded the same.

Figure 9 is a view corresponding to Fig. 8, but showing the next position where the final staking tool has crimped the spread portions of the pin over the bottom wall of the base. I

Figure 10 is a plan view after completion of the staking in accordance upper portion of the pin after the completion of the staking operation.

Referring to the drawings in detail, like parts being designated by like reference characters, there is shown in Fig. l a discharge device ii which may be a fluorescent lamp andconsist of an enclosing preferably tubular envelope l2, and filamentary electrodes l3 and il at opposite ends held by flare devices l5 and i6, which are respectively sealed to and close opposite ends of said envelope. To each end of the envelope is applied a base I! which, in the present embodiment, comprises a cup member 18 of an insulating thermosetting resin of the condensing typ to which are staked-a pair of contact pins l9 and ii. Such are desirably of the type known as head cha pins, as manufactured by the Bead Chain Company, Bridgeport, .Connlecticut. They are made from strip metal such as l bras-s, gilding metal, steel, or the like, formed by dies on a swaging machine. They may vary dimensionally in accordance with the size of the device with which used, but all are desirably bulged or beaded to provide a collar 22 between the ends, with shanks extending above and below said collar.

In the staking operation, the shorter, isinserted in a hole in the base and fastened or anchored by turning over the end with Fig. 9, showing the Y one end, preferably 44, resulting of the pin inside of the molded shell by the stak- I ing tool. in the past, the part of each pin received in the hole in the base has been cylindrical, with the result that in staking the only stress available for holding the pins in place, after final assembly, was that due to the crimping of the upper end portion, causing axial contraction, as the pins were initially made so as to fit the holes in the base to which connected without being forced in place, and during the staking operation the slight axial compression of the bead or collar 22 drew the metal of the cylindrical portion in the base hole radially inward, thereby further increasing the looseness of the fit.

It is necessary that there be a slight clearance between the shank of the pin received in the base and the hole in which it is received. In accordance with my invention I leave this same clearance, which is desirably about .002", but form a portion of said shank frusto-conical, or increasing from said cylindrical portion toward the collar 22 to a diameter slightly larger than'the receiving aperture in the cup member l6, so that there may be a forced fit between the cup member and pin when'the former is forced into engagement with the collar, whereby even though the collar is constricted axially during the staking operation, thereby pulling in on the shank to slightly decrease its diameter, such operation will not be great enough to destroy the tightness of the lit between said pin and cup member.

One embodiment of my preferred form of pin is shown enlarged in Figs. to 10, inclusive, as compared with the full size views of Figs. 2 and 4, and the reduced diagrammatic view of Fig. 3. Referring first to Fig. 5, it will be seen that one preferred embodiment of my pin involves an overall length of about .855" and a normal diameter of ,4,", a tolerance of .002" being allowed. The thickness of the metal forming the hollow pin I9 illustrated is desirably about or .015". The lower or longer portion 23 of the pin is desirably .59" from the hollow collar 22, which is desirably .07" long or axialy. The portion 23 is desirably cylindrical and .125" in diameter to near its free or lower end 25, where the metal is bent inward or contracted to leave an aperture 26, reduced in diameter as compared with the interior of the pin.

The upper or shorter section 21 of the pin beyond the collar 22 is desirably .005" larger in diameter than that of the cylindrical portion 23, say .130" near the collar, tapering for about half the distance to its upper end, or to the point 28. where it becomes the same size as that of the part 23. that is, .125" in diameter, and from there it remains cylindrical to near its upper or free end. where the metal is turned in to leave an aperture 29, of reduced diameter as compared with the interior.

The cup or shell l3 of the base I! has pinreceiving apertures 3| and 32 which are desirably truly cylindrical and of a, diameter allowing just the right clearace. For a pin of the size described, the diameter should be .128" or between .127" and .129". This I3 is fitted over the the pin, reaching loose fit semi-tapered end 2'! of as shown in Fig. 6, it binds before the collar 22 while making a slightlywith regard to the cylindrical portion.

means that when the cup In Fig. '7 is shown the cup l8 after having been forced down over the pin by the spring plunger in compression of the material of the cup at the point 33 and a movement thereof sure as heretofore. and

along the frusto-conical portion 21 to almost engage the collar 22.

As shown in Fig. 8, the prestaking operation of the pin in the bottom wall of the base involves the forcing of a tool 34 into the reduced aperture 29 of the pin, cutting the metal apart and spreading it, preferably as four

sections

35, 36, 31, and 40, at the same time causing a slight axial compression of the collar 22, which allows the cup l8 to further approach it. This action also causes a corresponding slight radial contraction of the frusto-conical portion 21 near the said c01- lar, but one not enough to destroy this tight fit of the cup with respect thereto, at the same time slightly expanding the upper end of the pin so that the fit is tight along substantially the full length of the engagement between the portion 21 of the pin and bottom wall of the base cup l8.

In Fig. 9 the final staking operation is illustrated in which the

sections

35, 36, 31 and 40, into which the upper portion of the pin has been cut and separated, are flattened by the tool 45 approximately to the inner surface of the lower wall of the cup l8, while at the same time said lower wall is forced into engagement with the collar 22, the latter being simultaneously further flattened or decreased in axial dimension as illustrated.

Considering the foregoing operations in connection with a practical device for performing them, as illustrated in Figs. 2 and 3, there is shown a machine 38 comprising a rotatable base member 39 holding a plurality of dies 4|, in this instance eight, said dies each having a pair of apertures 42 and" 43for receiving a corresponding number of pins, which are fed thereto at the position designated automatic pin feed in Fig. 3. Ejecting plungers 24 in the member 39, allned with the apertures" and 43, may be provided for automatically discharging the bases after completion.

The next position, designated base feed, is where a base is fitted over a pair of pins or a die after the base member 39 has moved through 45 or to of a revolution. After moving a quarter of a revolution further, the base is engaged by a spring plunger" 44 and resiliently pressed over the pins, as viewed in Fig. 2.

Upon moving 45' more the pins are encountered by a pre-staking tool 34 and cut or slit longitudinally and spread, as viewed in Fig. 2

and discussed in connection with Fig. 8. As a "final staking operation, the base, after advancing another 45 further, is encountered by. the final staking tool 45 which flattens the spread portions 35, 36, 3'! and 40', over the bottom portion of the base, as viewed in Fig. 2 and as previously described in connection with Fig. 9.

From the foregoing, it will be seen that I have devised a, novel form of contact pin particularly adapted for fluorescent lamp bases, and so designed with respect to its base cup that it may be staked tighter in a base without as much pres after staking therein it is secure and tight, not only axially but also radially, that is, not depending solely on the pressure between the bead or collar and the turnedover part on the inside of the base, thereby avoiding previous trouble encountered in connection wiht: such devices due to looseness of the contact p Although a preferred embodiment of my invention has been disclosed, it will be understood that modifications may be made within the scope and spirit of the appended claims.

ma ses 1 5 I claim: Y 1. A hollow metal pin the outer surface of which is divided by a hollow peripheral collar, that portion of said pin on one side of said collar being relatively long and generally cylindrical,

and that portion of said pin on the other side of said collar being preformed to taper therefrom slightly for about half the distance to the end of the pin to a smaller diameter and then continue generally cylindrical in order to provide a tight radial fit when inserted in a cylindrical aperture, of diameter slightly smaller than the maximum diameter of said tapering portion, but

slightly larger than said cylindrical portion, in a base for an electrical device to form a contact therefor.

2. A hollow metal pin to function as a contact for an electrical device and formed with a hollow aperture, and that part of said pin on the other side of said collar being about .195" long, and preformed, for force fit in a cylindrical aperture in said base about .128" in diameter, to start out about .005 larger in diameter than the longer cylindrical portion, taper for about half the distance toward the other end, to a diameterequal to that of said cylindical portion, and then continue to near said end as cylindrical, with the metal at the extreme end portion turned in to reduce the size of the aperture, in order to provide for a tight radial fit in said aperture.

5. A hollow metal pin to function as a contact for an electrical device and formed with a hollow peripheral collar dividing it unequally into two parts, the. larger part of its length being generally cylindrical from near one end to said collar and the part of said pin on the other side peripheral collar dividing it unequally into two parts, the larger part of its length being generally cylindrical from near one end to said collar and the part of said pin on the other side of said collar being preformed to be frusto-conical for about half the distance from the collar to the end to a slightly reduced diameter and generally cylindrical therefromto adjacent its end in order to provide a tight radial fit when inserted in a cylindrical aperture, of diameter slightly smaller than the maximum diameter of said tapering portion, but slightly larger than said cylindrical portion, in a base for an electrical device to form a contact therefor, both ends of said pin being rounded to form openings of diameters smaller than that of the pin interior.

3. A hollow metal pinto function as a contact for an electrical device and formed with an intertion and then continue to near the end as crime drical. with the metal of the extreme end portion turned in to reduce the size of the aperture, in order to provide a tight radial "fit when inserted in a cylindrical apertureabout .128" in diameter.

4. A hollow pin to function as a contact for.

a base of thermoaetting resin of the condensing type for an electrical device and formed of metal about .015" thick, with an intermediate portion bulged outwardly to provide a hollow collar dividing it unequally into two parts,- said pin having an over-all length of about .855", the collar having an axial length of about .07", the longer pin part to. one side of said collar being generally cylindrical, about .59" long and about in outside diameter, except at its free end where themetalisturnedintoreducethesileofthe 274,874

of said collar being preformed to be frustoconical for about half the distance from the collar to the end to a slightly reduced diameter and generally cylindrical therefrom to adjacent its end in order to provide a tight radial fit when inserted in a cylindrical aperture, of diameter slightly smaller than the maximum diameter of said tapering portion, but slightly larger than said cylindrical portion, in a base for an electrical device to form a contact therefor.

6. A hollow metal pin to functionas a contact for an electrical device and formed with an intermediate portion bulgedoutwardly to provide a hollow collar dividing it unequally into two the largerpart being generally cylindrical from near one end to said collar and about 3/ in outside diameter, and that part of said pin on the other side of saidcollar being preformed to start out about five thousandths of an inch larger in diameter than the cylindrical portion and taper, for nearly half the distance to the other end, to the same diameter as that of said cylindrical portion and then continue to near the end as cylindrical, in order to provide a tight radial ht when inserted in a cylindrical aperture about .128 in diameter.

. WILLIAM MAKENNY.

sameness cm The following references are of record in the file of this patent:

UNITED m mm'rs matron Pam-rs 1 ountry 1 nm em Britain m Number Number