US1989791A - Incandescent lamp stem - Google Patents

Description

Feb. 5, 1935.

J. A. DONOHOE 1,989,791

INCANDESCENT LAMP STEM Original Filed May 18, 1929 INVENTOR I Q. flO/VQf/OE Patented Feb. 5, 1935 INCANDESCENT LAMP STEM James A. Donohoe, Bloomfield, N. J., asaignor to Westinghouse Lamp Company, a corporation of Pennsylvania Original application May 18, 1929, Serial No. 364,116. Divided and this application June 22, 1932, Serial No. 618,709

3 Claims. (Cl. 176-36) This invention relates to the manufacture of will be drawn out of the arbor as well as the bulb. stems for incandescent electric lamps or similar It has been found that lamp stems made in acdevlces and is a division of application Serial cordance with the above practice present certain Number 364,116 filed May 18, 1929 for Incandesdisadvantages. Difilculty has been experienced in 5 cent lamp stems Patent No. 1,908,736. providing the aperture in the button since in 5 The manufacture of incandescent electric lamps forming this aperture it is necessary to employ a includes an envelope or bulb into which is sealed pointed tool which has a tendency to adhere to what is termed a lamp mount. The mount usualthe glass throwing the button out of proper posily consists of a flare tube, an exhaust tube, an tion with respect to the arbor and since any defarbor, as well as a pair of leading-in conductors ormation with repect to the position of the but- 10 all of which are consolidated in what is termed ton results in difllculties in connection with the a press to constitute a unitary structure. This insertion of the support wires, stems made in the structure is termed a stem and is ready to have above manner presented disadvantages from a support wires inserted into the arbor and a fllamanufacturing standpoint.

ment mounted on the support wires. After the The support wire inserting mechanism operates 15 support wires and the filament are in place and to insert the support wires by movement through the filament is connected with the leading-in definite paths and when the button is not propconductors the structure is termed a mount. erly positioned the ppor wires will be inserted The present invention is concerned with the an insuiiicient depth or not inser ed a wi h manufacture of stems to be completed as mounts the result that the automatic mechanism which 20 as constitute the internal structure of electrical must operate at relatively high speed is attenddevices, such as incandescent electric lamps. ed by an appreciable amount of loss through de- It has been proposed to construct a lamp stem fective stems. by supporting a length of glass tubing disposed It is an object of the present invention to proin axial alignment with the longitudinal axis d a p S in a l w a bor and.v a 25 of a glass flare tube. A pair or leading-in wires uniformly formed and accurately positioned butare also positioned within the flare tube and heat ton nis applied adjacent to the unflared end of the n th r o ject of the invention is o Provide a flare tube at which time the said end is comlamp tem h v n a nifo y p i n d button pressed, forming what is termed a press so as to and n ap r r for ha n the ar r. 3o fuse and consolidate the flare tube and the in- Another object of the invention is to provide a temally supported tube together, as well as to method of producing a lamp em having 8 h lseal-in the leading-in wires at the press portion. low ar r n a button f r ivin upport wires Means are provided for directing a jet of air and for closing an end of said arbor.

under pressure into one end of the centrally sup- Other objects and advantages of the invention 35 ported tube, while the portion termed the press i will be more fully understood with reference to still plastic so that the wall of the flare tube is the following descript together with the acpunctured and an aperture is provided for como mp y n drawing. in which munication between the internally supported tube Fi 1 ShOWS a p Stem a g a ho low arand the interior of a lamp bulb for exhaust purbor ready to b P d h an perture. 40 poses after the stem has been sealed to the bulb. 2 is a Side View 01 the Stem Shown in Fig.

When constructing a lamp stem as above de- 1 with a flame in position for heating a portion scribed the portion of the central tubular memof the wall oi. the arbor. ber extending from within the flare tube is uti- 3 is a vi w of a stem shown n i 2 with lized as the exhaust bulb and the end of the tubuan arbor having a hole therein and with a nozzle 45 lar member projecting outwardly from the press in posi n r directing under P sure into is utilized as an arbor to receive support wires. the a bo For the purpose or obtaining material to receive Fi 4 is a View Similar to 2 h win n the ends or support wires, which carry the fllaanne ng fir r d u an aperture in the ment, an end of the arbor is rendered plastic and arbor. 50 compressed into what is termed a button at which Fig. 5 is a view of a stem with means for formtime means are provided for leaving the top of ing a button at the end of an arbor, and the button open so as to afiord communication Fig. 6shows an arbor constructedin accordance to the interior of the hollow arbor. This is necwith the present invention and complete to supessary so that when the bulb is exhausted all gases port a lamp filament.

In practicing the present invention stems may be provided comprising an exhaust tube a flare tube 11 and an arbor 12. The arbor and flare tube which are initially of a continuous tubular member are united to the flare tube at 13 in what is termed a press which results from pressure being applied to heated portions of the positioned glass parts. Lead wires or conductors 14 and 15 extend through the press and are sealed therein.

A stem constructed as above described may then 10 be supported and heat provided by a flame 16 which may be directed against a wall 1'? of the arbor 12. When the wall is heated to the proper plasticity a nozzle 18 directed air under pressure into the arbor so as to puncture the wall thereof at the plastic portion, and an aperture 19 is provided. The perimeter of the aperture 19 may then be annealed by directing a flame 20' thereagainst.

.The stem may then be properiy supported and the exposed end 21 of the arbor may be heated by a flame 22 until plastic, at which time a pressure member 23 may be moved to engage the plastic end and form a button 24, at the same time closing the end of the arbor and producing a solid symmetrically positioned mass for the insertion of support wires 25 which may be applied by mechanism 26, comprising the usual inserting ram of a support wire inserting machine. After the support wires are inserted they may be bent upwardly as shown in Fig. 6 and a filament 2'7 may be mounted therein and the ends of the filament suitably secured to the lead wires 14 and 15.

A lamp stem constructed in accordance with the present method is provided with a hollow arbor having an end closure in the form of a button which is so positioned as to lie in a plane transverse to the longitudinal axis of the arbor. It is therefore possible to provide a glass mass into which the support wires may be securely and deeply embedded, and furthermore by reason of the provision of an aperture in the side wall of the arbor a larger opening is possible than has heretofore been obtainable and a more complete exhaustion of the interior of the arbor is attained.

It wili be understood that in the manufacture of an articie such as anincandenscent electric lamp it is extremely important that the various lamp parts be made with the proper degree of uniformity so as to meet the requirements of subsequent operations on other machines, and where a lamp part is made of such character that its physical accuracy cannot be depended upon, considerable loss is incurred causing shrinkage and obviously increasing the cost of production.

By reason of the present invention a lamp stem is" produced by a simple and convenient method and at the same time the required uniformity to meet practical manufacturing demands is attained.

Although a preferred embodiment of the invention is shown and described herein it is to be understood that modifications may be made therein without departing from the spirit and scope of the inventiori as set forth in the appended claims.

What is claimed is:

1. A glass lamp stem having a hollow arbor closed at one end by a compressed glass mass an enlarged glass mass closing the other end of said arbor, said arbor having an aperture in the cylindrical wall thereof intermediate its ends.

2. A lamp stem having a hollow arbor closed at one end by a press; a button formed from the material of said arbor closing the other end thereof, said arbor having an aperture in the o3 lindrieal wall thereof adjacent to said last mentioned' end.

3. A lamp stem comprising a flare tube, a hollow arbor, a press for consolidating said flare tube and closing one end of said arbor, an exhaust tube extending from said press, an aperture in said press communicating with said exhaust tube, the free end of said arbor being closed by an enlarged mass, said arbor having an aperture in the cylindricai wall thereof.

JAMES A. DONOHOE.

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