US1292991A - Thermostat. - Google Patents

Description

W. BARSTOW.

THERMOSTAT. APPLICATION FILED JUNE 19. 1918.

Patented Feb. 4, 1919.

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wn'ncn BAns'row, or SPOKANE, wAsnme'roN, ASSIGNOR r THOMAS rmnx nvm,

I citizen of the United States, residing at Spofollow'in 0F SEATTLE, WASHINGTON,

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To all whom it may concern:

Be it known that I, WELGH BARs'row', a

'kane, in the county of Spokane and State of Washington, have invented .new and useful Improvements in Thermostats, of which the is a s ecification.

One 0 ject o the'present invention is to provide in a thermostat a bi-metallic couple who'se inertia does not cause it to open or close when sub'ected to shock.

- A further 0 ject is to provide a bi-metallic element WhlOh will have a largemovement having regard to its overall dimen- .sions and weight, and which will be of great accuracy.

In the accompanying drawing, Figure 1 is a plan view of my improved thermostat;

Fig. 2 is' a sectional view thereof on the line cated upon the sup apair of metals having the ca 2-2 of Fig. 1 Fig. 3 is a sectional view on the line 3-3 oi Fig. 1.

Referring to the drawing, 1 indicates a suitable base, in which is plvoted a pin 2 having an eccentric head 3-rotatable in a support 4, so that said support is adjustable on said base by turning the eccentric pin 2.

It is-locked in any desired position by a looking screw 6 screwed into said base 1 and passing through a slot 5 in the support 4:.

From said. support extend u wardly a short standard 7 and a lon stan ard 8. 0 said standards are secure by screws 9 1n: ner ends of bi-metallic elements 11, 12, each of a general spiral'form, but extending in opposite directions from their fixed ends. The outer ends of said elements are-secured by ,pins 13, to caps14'having' yoke-shapeen tensions 16 in which are ivoted, by p1ns 17,

terminalportions of a ar 18, p1voted,,as

shown at 15, on a standard 20 centrally loort 4. One end of said bar is provided w1t means, as an aperture 19, for connecting it with a device for indicating the extent to which the elements 11, 12, are expanded or contracted Each bi-metallic element is composed of greatest practidifierence of heat 'coefliclent of expansion, namely, brass and ap roximately 36% nickel steel alloy, the brass aving the greatest commercially available coefiicient and the alloy the least, inasmuch as it is practically zero, and in some cases negative. The brass and alloy are arranged opposltely 1n the two bi-metallic elements, a brass strip 21 belng ar- Speoiflcation of Letters Patent.

Patented Feb. 4, 1919. v Applicaflonflled June 19, 1918. Serial No. 240,774.

ranged on the inside, and a strip 22 of alloy on I the outside of the spiral coil 1n one element and the positions be1ng reversed in the other element, a strip 23 of alloy being on the inside, and a strip 24 of brass being on the outside. Consequently while one element will expand, the other element will contract, with an increase in temperature, and since their outer ends are pivoted near the opposite ends of the bar 18, which is free to oscillate about its center, the thermostat so composed is statically balanced. Its inertia does not cause it to open or close when subjected to shock. 7

Moreover, the two coils linked together, as shown, tend to mutually overcome any slight differences of expansion due to hard spots in the metals, or for other reas0ns,:and have therefore only one-half the error which each would have alone.

Another advantage of the present construction is the eater area exposed for a given crosssectlon of metal, the device thereby responding. quickly to changes in temperature.

I claim 1. A thermostat comprising an oscillatory device and thermostat1c elements, ends of which are secured to portions of said device on opposite sides of its center of oscillation, said elements being arranged, one to 'expand, and the other to contract with an increase in temperature, said' device bein provided with means for assisting to in icate its movements due to said expansion and contraction. a

[2. 'A thermostat comprising an oscillatory device and bi-metallic elements each secured fixedly at one end, the other ends of said elements being secured to ortions of said de- ,vice .on o osite sides 0 its center of oscillation, sa1 bi-metallic elements being arranged, the one to expand andthe other to contract, with an increase in temperature,

said device being provided .with means/for vice on opposite sides of said pivot, said hiassisting to; indlcate its movement due to.

metallic elements being arranged, the one to expand, and the other to contract, with an increase in temperature, said device being provided with means for assisting to indicate its movement due to said expansion and contraction.

4. A thermostat comprising a device/ar ranged to oscillate about an approximately central pivot and bi-metall'ic elements each 10 secured fixedly at one end, the other ends of said elements being pivotally secilred to portions of said device on opposlte sides of said 7 center of oscillation, the metals of the two elements havin diflerent heat coeflicients of expansion and eing arranged oppositely in the respective elements, saiddevice being provided With means for assisting to indicate its movement due to a change-intemperature.

WELCH BARSTOW.

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