US1161840A - Electric-lighting device. - Google Patents

Description

C. E. CAMPBELL.

ELECTRIC LIGHTING DEVICE.

APPLICATION FILED APR.2. I914.

Patented Nov. 30, 1915 M; 2/2 1 H /z2 -21! If 2,1 M

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CHARLES E. CAMPBELL, 0F LYNN, MASSACHUSETTS, ASSIGNOR 0F ONE-HALF TO FREDERICK R. CAMPBELL, OF LYNN, MASSACHUSETTS.

ELECTRIC-LIGHTING DEVICE.

Specification of Letters Patent.

Patented Nov. 30, 1915.

Application filed April 2, 1914. Serial No. 829,001.

To all whom it may concern:

Be it known that I, CHARLEs E.- CAMP- BELL, a citizen of the United States, residing at Lynn, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in Electric-Light ing Devices, of which the following is a specification.

My invention relates to improvements in electric lighting devices and the object of my improvement is to provide means for supplying the lighting current to a filament inclosed in a hermetically sealed glass chamber or bulb without the use of leading in wires or conductors that pass through the glass wall and thereby obtain certain susuch leading in wires or conductors are used.

In the accompanying drawing, Figure 1 is a side elevation of my improved lighting device. Fig. 2 is a plan view of the same. Fig. 3 is a sectional view on the line 01-00 of Fig. 2, the core being shownin side elevation.

My improved electric lighting device comprises a filament 10 of tungsten or other material suitable for incandescent lighting inclosed in a bulb 11 of special construction and with which there is incorporated in a special manner tobe described a transformer 12. The lower part of the bulb 11 is of any form suitable for housing the filament 10. As shown the filament 10 is short and straight and extends laterally across the central part of the said lower portion and the tip 13 is just below the same. The upper portion of the bulb 11 is relatively extended for an appreciable distance, suitably to have the transformer 12 incorporated therewith and comprises a cylindrical peripheral wall 11 and an axially extending recess 15 having a cylindrical wall 16 concentric with the outer wall 14. Between the outer wall 1% and the inner wall 16 there is an annular space 17, within the bulb walls and constituting an extension of the bulb space in which the filament 10 is housed. The secondary winding 18 of the transformer 12 is housed in the annular space 17 and substantially fills the same. The conductors 19 extend. directly from the secondary winding 18 to the filament 10, and they may be provided with a brace or bridge 20, preferably of glass, at some point intermediate the ends whereby they are crossconnected mechanically and positively positioned relatively one to the other. The core 21 and the primary winding '22 are positioned in any suitable manner relatively to the secondary winding 18 to operate inductively therewith. Obiously, in order to do this, one leg of'the core; shown as '23, must be positioned axially with reference to the secondary winding 18, and the primary winding 22 is conveniently positioned concentric with the said leg 23 and with the secondary winding 18.

I find it convenient to mount the primary winding 22 directly on the leg 23. as shown.- The primary winding 22. mounted on the leg 23, as mentioned. substantially fills the recess 15. The return portion of the mag netic circuit'of the core 21 may be formed in plurality of yokes 25. The core as shown is 1 made up of four similar units 26. each of which is built up of U-shaped laminations of ordinary form to provide a square crosssection for the arms 2-1. The four individual arms 2 1 on one side of each of the units 26 are combined to build up the axial leg 23, and which has a square cross-section.

It is understood that the constructive details may be varied in various ways from those shown and described. It will be noted that the current supplied to the filament is delivered directly from the secondary of the transformer, and the current is accordingly delivered thereto by induction through the walls of the bulb, and without leading in wires penetrating the glass walls of the bulb.

Vhile there are advantages in the use of .the construction described with filaments of would be made of platinum, and correspond ingly expensive. Furthermore, with low voltage, as mentioned, there would be excessive drop in voltage and also loSs of energy due to the length of the leading in wires and the means of delivering the current thereto by such methods as are ordinarily used for this purpose. These difliculties are obviated by my invention. As an example, I have successfully used a primary winding for 110 volts 'and a filament for one volt. The air may be exhausted from the bulb 11 so that the filament 10 will be operated in a vacuum or the said bulb may be supplied with a special arrangement of gases. \Vith such a special. arrangement of gases a filament such as shown, that is short and of relatively large diameter, and of correspondingly large current capacity, gives the best efficiency, as if the filament is of small diameter and great length the percentage of loss by the heat being conducted through the gas, which usually amounts to three quarters of an atmosphere, is appreciably greater than if the filament is of only a fraction of the length and correspondingly heavier. In such cases the voltage drop due to leads and contacts under ordinary methods of construction is liable to be excessive and these conditions are avoided by my invention.

I claim as my invention 2- 1. In combination, a hermetically sealed glass bulb, a secondary winding and a filament housed in the said bulb, a primary winding, and a core having a plurality of legs. said bulb having a recess extending inwardly along the axis of the said secondary winding, the said primary winding and one leg of the said core being housed in the said recess, and the other legs of the said core being distributed over the outer side of the said secondary and extendingalong the said bulb in parallel relation to the said first leg.

2. In combination a hermetically sealed glass bulb, a secondary .winding and a filament housed in the said bulb, a primary winding, and a core having an inner and an outer leg, the said bulb having a recess extending inwardly along the axis of the secondary winding, the said primary and the said inner leg being housed in the said recess, and the said outer leg of the said core being positioned on the outer side of the said secondary and extending along the said bulb in parallel relation to the said inner leg.

CHARLES E. TAMPBELL.

Witnesses:

JENNIE SCHwAnTz, MAE HAGAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, D. 0.

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