US1335709A - Electrical time-switch - Google Patents

Description

L. H. I. T. BIZI'IIIISEII.

ELECTRICAL TIME SWITCH.

, APPLICATION FILED Aue.29, 1917.

1,3353%. Patentad Mar. 30,1920.

- Q I I 4 s H 8 79 LAUBI'IZ HARALD JOHAN THEQDOR BJfiRNSEN, OF COPENHAGEN, DENMARK.

ELECTRICAL TIME-SWITCH. I

Specification of Letters Patent. Patented ltlar. 30, 1920.

Application filed August 29, 1917. Serial No. 188,846.

To all whom it may concern:

Be it known that I, LAURITZ HARALD JOHAN Tnnooon BJoRNsnN, subject of the King of Denmark, residing at Copenhagen,

Denmark, have invented certain new and useful Improvements in Electrical Time- Switches, of which the following is a specification.

The present invention consists of an electrical time switch of the kind where the heat produced by an electrical current causes a body to expand, the said expansion and subsequent contraction being utilized to close or interrupt an electrical circuit. I

r The essential feature of the invention is a heat-operated member closing, by means of the heat produced by the operating current, the circuit for another heat-operated member which thereby closes the main circuit. i

On the drawing is shown, in diagram, one manner of. constructing the invention as utilized for a so-called staircase automaton.

1 and 2 are the feeding wires, positive and negative respectively, 3 the lamps, 4 the push-button switches and L, M, P, T the connecting terminals. 5 and 6 are-two metal bars firmly interconnected at both ends, one of'the bars facing anincandescent lamp 7 so that the latter when burning heats the bar 5 which, by the elongation produced thereby, moves a contact 8 toward an adjusting screw 9.

15, 16, 17 18 and 19 are a contact system corresponding to 5, 6, 7, 8, 9. p

The apparatus acts in the following manner:

By the depression of oneof the push-.

buttons 4, a clrcuit is closed from the positive terminal P and through the switch 4, the terminal T and the incandescent lamp 17 to the negative terminal M.- The heat radiating from the lamp will heat the metal bar 15 and thereby, within a short time, it will bring the contact piece 18 into contact with the screw 19. By this contact, a new circuit is closed from the positive terminal P and through the contacts 18,-19 and the "incandescent lamp 7 to the negative termi- 'nal M. The heat radiating from the incandescent lamp 7 will soon bring the contact piece 8 into contact with the contact screw whereby a new circu t-the main circuitis closed from the terminal P throu h the insu lamps 3, the connecting terminal the whereby the circuit between the incandescent lamp 7 is broken, and the bar 5 begins to cool down. When the cooling has progressed so far that the contact 8 is brought out of contact with the contact-screw 9, the main current is interrupted and the lamps 3 are extinguished.

Ex eriments have shown that it is practicab e to reduce to about one second the time during which it is necessary to depress a push-button in order to cause the lamps 3 to burn and, further, that by adjusting the screws 9 and 19 the length of time during which the lamps continue to burn may be varied between 1 and 5 minutes or, if desired, between still wider limits.

Ordinarily, the pressure on the push-but-v ton 4 will be released as soon as the lamps 3 begin to burn. If it besdesired, however, to have the lamps burning somewhat beyond the normal period, it is only necessary to keep the button depressed for a short time for instance one second-after the lamps have been lighted. Besides, it is feasible, at any time durin a burning period, to initiate a new period y depressing a push-button once more.

If oneof the push-buttons happens to be sticking in the circuit-closing position, no other harm is roduced than that all the lamps 3, 7 and 1% continue to burn.

When the metalbars 5 and 6 as well as the bars 15 and 16 are made of one and the same metal, the result is attained that the the apparatus having become heated by having been used several times at short intervals. If necessary, the bars 6 and 16 may beinsulated against heat action, for instance by bein wound by or .inclosed in some heat fitting substance, or by being made narrower than the bars 5 and 15, so that the latter protect them against the radiating heat.

A slower. cooling of the bars 5 and 15, if desired, may be attained b insulating them on the side m? facing the i amps.

Instead of the heat-operated devices 5, 6

' and 15, 16 there may be used heat-operated devices of any suitable construction, where a heating and subsequent cooling causes a circuit to be closed and broken, respectively.

The apparatus described is free of the relatively expensive and unreliable clockworks and also of electro-magnets, and .it fills all the requirements to be made to a time switch, in respect to simplicity of con-v struction cheapness and reliability of performance. p

The main condition for attaining the high efiiciency in such simple apparatus is t e nearly instantaneous heating of the bars 15 and 5 caused by the radiating heat from the incandescent lamps l7 and 7, .in connection with the subsequent very slow cooling.

Having now particularly described and ascertainedthe nature of my said invention and in'what manner the same is "to be performed, I declare that what I claim is In an electrical time switch, a circuit having an electrical heat-emitting member a second circuit having a thermal expansihle circuit-closing element "in operative relation to the aforesaid heat-emitting member of .the first circuit, said second clrcuit having alsoan electrical heat-emitting member a main circuit having a thermal expansible circuit-closing element in operative relation to said heat-emitting member of said second circuit, and means for breaking said first circuit, whereby, after the main circuit is closed, it may be broken, after the lapse of a time'interval, by the successive automatic cooling of the said circuit closing elements and the successive automatic breaking of their respective circuits.

In testimony whereof the foregoing specification is signed in the presence of two witnesses. Y

, mumrz 11.4mm) Jon rranonoa BJGBNSBN.

Witnesses:

Jul-ms LDMANN, .Av Gm'nsme.

Images