BEST AVAILABLE COP T. A. EDISON. Thermal-Regulator for Electric-Lights.
No. 214.637. Patented April 22,1879.
7 through w ilch the current passes. :top plate, to which the spiral c is connected.
UNITED s'rs'rns PATENT OFFICE.
.rl-IOMAS A. EDISON, OF MENLO PARK, NEW JERSEY IMPROVEMENT IN THERMAL REGULATORS FOR ELECTRIC LIGHTS.
Specification tormln z port of Letters Patent No. 214,637, Tut-ed April .22, 1879; M m m November 18, 1878.
To all 101mm it may concem Be it known that I, Tnoms ALVA EDISON, ,of Menlo Park, in the State of New Jersey, have invented nu Improvement in Electric Lights, of which the following is a specification The object of this invention is to devise a reliable and economical electric lamp, to give light by incandesccnce-due to the passage of the electric current through conductors of electricity, so that a great number of lamps may be used in one electric circuit.
The invention consists in-causipg the heat generated by the incandescent conductor to expand the air or fluid in the containing-chamb'er as its temperature rises, the ressure thus created serving to move outwar ly a yielding material-such as a diaphragm-Which, in its turn, serves to control the passageof the electric current through the incandescent bodyby means-of cont-actpoints or circuit-regulators, and thus the temperature of the incandescent conductor will be regulated automatically.
1 In the drawings, Figure 1 is a sectional elevation. of the electric lamp, and Fig. 2 is a plan of a portion of the same. The other figures are separately referred to.
a is a glass tube or vessel, containing spiral or strip 0 of iridium or equivalent metal, I; is the The glass tube is secured to the metallic standard Q. a is a diaphragm closing the bottom of the lower chamber. There is a par- .tition between the chamber containing the spiral c and the chamber of the diaphragm but aircirculates freely between the chambers through the holes (1 d d d.
When the spiral is heated by the passage of the current, the air in thechambers expands and bulges the diaphragm outwardly. 0n the center of the diaphragm is aplatiuapoint,
" f, iminediatelyopposite another platinapoint,
g, on a spring, 1:. This again is opposite another platina point, we, on the screw 1):. m is a-disk of insulating material, on the top of which is a brass ring in electrical connection with the spring h. A rubbing contactspring,
11, connects this ring to the insulated plate R and the binding-post 3 on the base. The
frame Q is connected to the other binding-post,
1. A'wire, 20, connects the spiral of the light with the plate It and binding-
post
2.
When no current passes inthe circuit containing this instrument, the air in the chamber is of the same pressure as the atmosphere, and the points fend g and n are not in con tact. If, now, the current is allowed to circulate in the line, it passes, say, from bindingpost'2 to R, thence through
wire
20 to the top 1:, down through spiral c to base Q, to the other binding-post, 1.
'VVhen the spiral 0 reaches within a few degrees of its melting-point, the expansion of the air will have bulged out the diaphragm c and brought the points f and 9 together, thus shortcircuiting the current from the spiral, as it now must nearly all pass from binding-
post
2 to R, thence through spring 4: to the ring 3 throu h spring h to g, through f to diaphragm e, to and back to binding-
post
1. When thus short-circuited thetemperature-of both the air and spiral fall by radiation, and when it reaches a certain point the diaphragm and point f leave 9, and the current again passes through c and raises its temperature, and the same action takes place. This regulation is so rapid that the eye does not perceive any diminution in the strength of the light. The object of the contact between g and nis, that in case f and gshould fail to make contact the short circuit would still take place, as n and fare both connected to Q.
It is obvious that this method may be hpplied in many ways. For instance, the diaphragm might give motion to a lover or spring through which the contacts might be made, and this second'chamber may be separated from the one containing the spiral c, as shown in Fig. 3. A. tube, d, leads from the chamber containing the spiral to the second chamber, m, closed by the diaphragm c n is a lever, which is moved by the movement of the diaphragm, and serves to short-circuit the spiral 0 when it comes incontact with the point 1).
Mercury may replace air in the tube (1 and chamber m, the pressu-reo'l the air or gas in a acting through such mercury on the diaphragm e or the mercury may come into contact with the point p to make direct circuit through the mercury.
The incandescent conductorsmuydie made BEST AVAILABLE COP vessel containiiig the ligbt acting automnrb cally in the electric circuit,- substantially as set forth.
Signed by me this 14th day of November.
I do not thei efore herein claim my feature set A. I). 1873.
forthlin said pritpr applicaticn.
I'ciaim as my invention- The method specified of sre-guiating' the temperatnreqf thincamigscentlight-giiing body, by the expansion q." the ail-0r gets; in me mused THOMAS A. EDISON.
Witnesses:
S'rocmon L. GRIFFIN, CHAS. PATQHELOR.