US2427096A - Electrical device and molded stem therefor - Google Patents

Description

9 1947 D. s. GUSTIN ELECTRICAL DEVICE AND MOLDED STEM THEREFOR QE'iginal Filed'Dec. l, 1938 ATTORNEY INVENTOR .0. J- 60677.

Patented Sept. 9, 1947 ELECTRICAL DEVICE AND MOLDED STEM THEREFOR Daniel 5. Gustin, Bloomfield, N. 1., assignor a) Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Original application December 1, 1938, Serial No.

1943, Serial No. 494,142

13 Claims.

molding of the flares, cups or base portions thereof.

The principal object of the invention, generally considered, is the manufacture of electrical devices such as discharge lamps, in which the lead-in conductors are made rigid enough to serve as outer contacts or posts in order to dispense with basing, the flares or cups being formed of glass molded therearound to form stems, either by softening and pressing glass blanks, or by pouring molten glass around the leads while held in place.

Another object of the invention is the manufacture of electric lamps, especially of the discharge type, in which the outer electrode leads are made so rigid that they are adapted to engage the sockets directly without basing, said leads being consolidated directly with glass cups or flares, electrodes mounted on the inner ends thereof, and the molded glass then sealed to the bulb proper.

Other objects and advantages of the invention, relating to the construction and arrangement of the various parts, will become apparent as the description proceeds.

Referring to the drawings:

Figure 1 is a fragmentary elevational view, partly in section, of an electrical discharge device embodying our invention.

Figure 2 is an end elevational view of the device of Figure 1.

Figure 3 is a fragmentary sectional view on the line III-III of Figure 2, in the direction of the arrows.

Figure 4 is an axial sectional view of one of the blanks used for making the glass baseor flare which holds the heavy leads of a discharge or other electrical device, such as shown in Fi ure 1.

Figure 5 is an elevational view of one of the heavy leads used in making a base for a discharge or other electrical device, such as shown in Figure 1.

Figure 6 is a fragmentary vertical sectional view, with parts in elevation, showing one embodiment of a machine for manufacturing glass cupslor bases for devices such as shown in Figure Divided and this application July 10,

2 Figure 7 is an axial sectional view of the right hand end portion of the device illustrated in Figure l, with the end cup finished by placin wax-like material therein.

Referring to the drawings in detail, like parts being designated by like reference characters,

- and first considering Figures 1 to 5, inclusive,

there is shown, as one embodiment of the invention, an electrical device 20 of the discharge type, comprising an envelope or bulb 2| in the form of an elongated hollow cylinder containing some mercury 22, the ends of said envelope being closed by glass discs, cups or bases 23 and 24. The cup 23 has incorporatedv therewith lead-in conductors 25 and 26, while the cup 24 has incorporated therewith lead-in conductors 21 and 28, to form stems, the conductors 25 to28, inclusive, being so rigid that they are 'adapted to serve as outer contact posts and eliminate the necessity for the usual basing.

The inner ends of the leads 25 and 26 carry a filament 29, serving as one electrode, and the inner ends of the conductors 21 and 28 carry 'a similar filament 3!, serving as the other electrode. The filaments may be formed of tungsten or other suitable material, with or without oxide coating to render them more eflicient for the emission of electrons. The ends of the filaments 29 and 3| are connected to their lead-in conductors in any suitable manner, as by means of spot welding.

The conductors 25 to 28, inclusive, are formed of suitable material, tungsten and nickel alloys being mentioned as examples, and the. glass sealed therearound is made of such a composition that it will not crack upon cooling around the lead-in conductors. For example, if soft glass is used for the base, then nickel iron, chrome iron, dumet or other alloys of the proper coeflicient of expansion are desirably employed as the lead-in conductors. If (Corning code) No. 1'72 (or hard aluminum borosilicate) or No. 704 or 705 (both soft borosilicate) glass is employed, the lead-in conductors are formed of beaded molybdenum. Or if No. 704 or 705 glass is employed, such conductors may consist of "Kovar" (which is a patented cobalt-nickel-iron alloy), as for application in sodium and mercury vapor lamps. If No. 775 or 705 (both soft borosilicate) glass, or "Nonex'? or No. 7'72 (or lead borosilicate) glass is used, then beaded tungsten leads are desirably employed to match the expansion of said glass.

It will be noted that the cup or base 23 has an exhaust tip 32 while the cup or base 24 is without such a tip, as it is unnecessary to exhaust at more than one end. The tip 32 is protected by making the cup reentrant or concave outwardly, and the concave portion of both cups 23 and 24 may, if desired. be finished by filling with a material 50 like sealing wax as illustrated in Fig. 7.

From a consideration of Figs. 1, 2 and 3, it

will be seen that by virtue Of the bases or cups 23 and 24 being reentrant, an exterior recess 36 is formed in each, defined by the generally flat end or bottom wall portion, the outer peripheral rim or base edge extending at an angle to said bottom wall portion, and the reinforcing bosses 40, over or on less than half the bottom wall area, and through which the lead-in conductors 26 and 26, or 21 and 28, as the case may be, respectively extend, as shown in Fig. 3. n account of this recess the exhaust tube of the cup 23 may, if desired, be tipped off within its base, without danger of fusing or damagin the base, the thickening reinforcement or bosses 40, or in-v luring the lead-in conductors, if care is exercised and a small tipping ofi flame employed. If perchance, the extreme end of the tip 32 pro- Jects slightly, as illustrated in Fig. 1, after tipping-oil and removal of the outer end of the exhaust tube, the projecting end portion may, be-

fore it hardens completely, readily be pushed orv flattened so as to lie entirely within the recess 36, and not project beyond the plane of the peripheral edge portion of the cup 23. The bosses 40, which have flat outersurfaces parallel to the bottom wall portion, are formed by thickening parts of said bottom wall portion toward or to the outer surface or plane of the peripheral rim, flange, or base edge portion,

Referring now to Fig. 6, there are shown portions of one embodiment of a machine for forming such bases as Just described and the manufacture of one, such as designated by the reference character 23, with an exhaust'tube will be disclosed.

The machine, as shown in this figure, comprises a lower mold element 33 having pockets or cavities 34 in its upper face for receiving relatively rigid or thick one-piece lead-in conductors 25 and 26, such as those designated as forming parts of the cup or glass base 23. The lower mold element 33 also has a central aperture 36 and a shoulder 61 on the upper mold element 65, Undesired depression of the supplemental mold member 56 is prevented by means of a stop 62. connected to the upper mold element 35, and received in a corresponding slot in the supplemental member 56. When the upper mold element descends, the supplemental member telescopes with the lower mold member 33 and engages an annular member 66 connected thereto. as by means of a set screw 10.

The upper mold element 55 is provided with pockets or apertures 63 and 64, receiving the upper ends of the leads 26 and 26, and desirably having their upper ends vented to the atmosphere, as by means of small apertures 65 and 66. to relieve compression as the mold closes.

In order to heat the moldable material. such as the glass blank 19 and the upper end of the exhaust tube 31 during the process of forming the disc cup or base for the device of Figure 1, I provide suitable flres 61, 66 and 66, issuing from nozzles 11, 12 and 13, carried by piping 14, supplied with suitable combustible gas from manifold 16, carried by and rotatable with hollow shaft 16, driven by suitable means so that it rotates on the rod 66, and receiving a gaseous mixture through registering ports 60 and 80 from the hollow collar 11, held against rotation with the shaft 16, and receiving gas from pipe 18.

The manner of using the machine of Figure 6 for making glass cups or bases, such as designated by the reference character 23 is desirably as follows:

The first step in the operation, is desirably to place an exhaust tube 31 in the lower mold element, where it rests on the upper end of the air receiving a glass exhaust tube 31, the lower end of which rests on the upper end of a tube 38, desirably formed of metal and adapted to carry compressed air to said exhaust tube. The lower mold element may be held in position in a support 33. Air may be conducted to the lower end of the tube by any desired means, such as 'a rubher tube from a suitable source of supply. The

erated by a rod 56. Operable in the upper mold element 65 is a plunger 51. The upper mold element carries an annular supplemental mold portion 33, vertically slidablethereon and held in normal or lower position, as" by means of coil spring 69, operating between its upper surface tube 36, as shown in Figure 6. The lead-in conductors 26 and 26 are then placed in their pockets 34 and 33, in the lower mold element, as shown in the same flgure. A section 19 of large diameter glass tubing, corresponding in volume with that of the cup to be formed, is then placed on the lower mold element 33 so that it encircles the upper end of the exhaust tube 31 and the leadain conductors 26 and 26, as shown in Figure The flres 61, 63 and 66 are then rotated, by turning thehollow shaft 16 by any suitable means, not shown, until the glass of the section 13 softens and draws around the leads 23 and 26. The action of the softened glass in wetting the leads 26 and 26 and drawing in around the upper end of the exhaust tube 31,- is facilitated by the direction of flow of the flres 61, 63 and i6, and the surface tension of the nearly molten glass.

When the glass becomes sufilciently soft, the upper mold element 65 is brought down as by a downward movement of its supporting rod 66, causing the supplemental mold member 63 to telescope with the lower mold element 33, ensue the annular member 66. and the glass to be pressed into the desired shape between the upper and lower mold elements 56 and 33. The glass, at the same time, is pressed into consolidating engagement with the upper end of the exhaust tube 31, the glass above the exhaust tube opening being thinned by the downward movement of the plunger 61, which also insures a good seal with the exhaust tube.

The next step in the process, is to raise the upper mold element 55, slightly, while leaving the plunger 61 in engagement with the formed cup or base 23, whereby said base is detached from the upper mold element and remains resting on the lower mold element 33. Both upper mold element 55 and plunger 51 are then raised out or the way.- The diaphragm or thin section of glass closing the upper end of the exhaust tube 31, is now broken before the glass has had a chance to harden, by compressed air directed upwardly through the exhaust tube. a

The completed base or cup 23, with the exhaust tube 31 sealed thereto, is then ejected or stripped from the lower mold element 33, by an upward movement of the air tube 38, as by means of the cam acting on a roller secured thereto, whereupon, an operator may remove the formed base or cup completely from the machine, preparatory to making another one,

It will, of course, be understood that in order to make the base or cup forming operation continuous, I desirably have a series of mold elements and associated parts, such as shown in the figure,

and cause the same to move along to first receive the elements 31, 25, 25 and 19, heat and compress them to consolidate and form the base or cup, and then raise them for removal.

The parent Patent No. 2,324,385'may be referred to for further illustrations of the machine of Fig. 6 and other embodiments for making the cups or bases disclosed.

From the foregoing disclosure, it will be seen that I have devised a novel form of glass stem, base, or cup, particularly adapted for discharge devices. Thecups, as formed have incorporated therewith, rigid prongs having the double function of lead-in conductors and outer contact members, thereby enabling me to dispense with a subsequent basing operation.

Although a preferred embodiment of my invention has been disclosed, it will be understood that modifications may be made within the spirit and scope of the appended claims.

I claim:

l. Inan electrical device, a molded glass cup, said cup being concave outwardly forming a cavity within a peripheral rim, bosses disposed in said cavity and merging with said rim, lead-in conductors extending through said bosses, and an exhaust tube disposed between said bosses.

'2. In an electrical device, a glass envelope, a glass base closing an opening of said envelope and attached thereto, said base havin an outwardly opening recess, spaced bosses arranged within said recess and merging with said rim, an exhaust tube carried by the base, extending into said recess, and spaced from said bosses, and lead-in conductors passing through said bosses.

3. In an electrical device, a glass cup, said cup being concave outwardly forming a cavity within a peripheral rim, a boss disposed in said cavity, a lead-in conductor extending through said boss, and an exhaust tube disposed in said cavity adjacent said boss,

4. An electric device comprising an elongated glass envelope having an end closed by a pressed glass disc fused to the said end of said envelope, conductors extending through and fused directly to said glass disc and projecting outwardly therefrom to function as contact pins, a centrally arranged hollow re-entran-t projection on said glass disc extending into said envelope and providing a recess in the outer surface of said disc, an exhaust tube depending from the inner end of said projection and sealed off within said recess, and means secured to said disc and 'covering at least the portion which is recessed.

5. An electric device, comprising a glass envelope, a glass base closing the opening of the envelope and attached thereto, said base having an exterior recess extending substantially to the marginal edge of the base, spaced reenforcing bosses arranged within the exterior recess and formed integral with the base, an exhaust tube carried by the base and extending into .the recess and spaced fromthe reenforcing bosses, and terminal contact units embedded in the reenforcing bosses,

the arrangement being such that access may be spaced from the reenforcing bosses, the arrange- I ment being such that access may be had to the exhaust tube through the exterior recess to fuse and tip of! the same within the recess without liability of fusing the base or the reenforcing bosses, and a reenforcing filling for the exterior recess serving to reenforce the base and having the reenforcing bosses and parts of the terminal contact units embedded within such reenforcing filling.

7. In an electrical device, a base formed as a glass cup, said cup being concave outwardly forming a cavity within a peripheral rim, a part of said cup being thickened to' form a boss within said cavity, and a lead-in conductor sealed through said boss.

8. In an electrical device, a base formed as a molded glass cup opening outwardly, the bottom portion of said base being thickened forming a boss, and a rigid lead passing through said thickened portion in order that its outer portion may function as a contact post.

9. In an electrical device, an envelope open at opposite ends, and a glass base at each end of said envelope, each base having a bottom wall portion, lying in a plane-generally perpendicular to the axis of said envelope, and a peripheral rim portion comprising a flange offset from, and parallel to, the plane of said bottom wall and fused to the adjacent edge of said envelope, part of each bottom wall being thickened toward the plane of said flange and forming at least one flat-topped boss small in area compared to the bottom wall area, and a rigid lead-in conductor sealed through each boss to function as a contact terminal.

10. An electrical device comprising a molded base member having a bottom wall portion, a reinforcing boss thereon and small in area compared with said wall portion, a one-piece conductor secured in said boss and rigid to serve as an outer terminal or contact post, and a peripheral rim portion on said base extending at an angle to said bottom wall portion, said boss having a flat outer surface parallel to and offset from said bottom wall portion toward the plane of the edge of said rim portion.

11. In an electrical device, a molded base having a bottom wall portion, a part of said portion being thickened over only a relatively small portion of its area, a one-piece rigid conductor secured to and extending through said thickened part to serve as an outer terminal or contact post, and a peripheral rim portion on said base extending at an angle to said bottom wall portion, said thickened part having a flat outer surface parallel to 7 and ofl set from said bottom wall portion toward the plane oithe edge of said rim portion.

12. In combination, a molded cup for an electrical device comprising a bottom wall portion, a part of which is thickened for reinforcing purnmanncns man The following references are of record in the 5 file of this patent:

poses over only a relatively small portion or its area, a peripheral rim encircling said thickened part, and one-piece rigid conductor means secured in said thickened part torserve as outer contact terminal means, said thickened part having a flat outer surface parallel to said bottom wall portion and ofiset therefrom toward the plane of the edge of said rim.

13. An electrical device comprising a molded base with an end wall, reinforcing boss means on less than one half of said end wall area, a peripheral rim encircling said boss means, and one-piece conductor means secured in said boss means to serve as outer contact terminal means, said boss means having a flat outer surface parallel to and offset from said end wall toward the plane of the edge of said rim.

DANIEL S. GUBTIN.

UNITED STATES PATENTS Number Name Date 2,219,574 Franeckel Oct. 29, 1940 2,032,232 Strickland Feb. 25,1936 2,006,818 Zimber July 2,1935 2,056,621 Roberts Oct, 6, 1936 2,079,801 Grant May 11, 1937 2,098,080 Wright Nov. 2, 1937 2,137,174 Marshaus Nov. 12, 1938 2,147,584 Thomas Feb. 14, 1939 2,216,247 Ledig et al. Oct. 1, 1940 2,235,135 Ernst-Gunther Andresen Mar. 18, 1941 FOREIGN PATENTS Number Country Date 4,746 Great Britain Mar. 4, 1893

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