US375576A - Metallic thermometer - Google Patents

Description

(No Model.)

T. W. SHEPHERD.

METALLIO THERMOMETER.

No. 375,576. Patented Dec. 27, 1887'.

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U ITED STATES PATENT OFFICE.

THOMAS WM. SHEPHERD, OF PEABODY, MASSACHUSETTS.

METALLIC THERMOMETER.

SPECIFICATION forming part of Letters Patent No. 375,576, dated December 27, 1887.

Application filed February 18, 1887. Serial No. 228,058. (No model.)

To aZZ whom it may concern.-

Be it known that I, THOMAS WM. SHEP- HERD, of Peabody, county of Essex, and State of Massachusetts, have invented an Improvement in Thermometers, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

In the manufacture of thermometers of the class known as metallic thermometers much difficulty has been experienced in supporting the thermal strip or coil in such a manner that it shall be entirely free from contact with .the inclosing-case, to thereby more reliably respond to the exact variationsin temperature.

This invention has for its object to provide a metallic thermometer with eff cient means for supporting the thermal strip or coil and its co-operating parts free from contact with the inclosing-case, the means employed being such thatfree circulation of air is permitted throughout the chamber in which the said coil is supported, that the coil may be most susceptible to the changes in temperature and more reliably responsive.

In accordance with this invention the thermal strip or coil is supported upon the under side of the dial, and the pointer which sweeps over the dial is actuated by means of the thermal coil. The dial thus supporting all the operating parts is placed within the inclosing-case and made to rest upon the upper edge of a perforated supporting-strip, the width of which is sufficient to support the dial so that the thermal strip will be free from contact with the inclosing-case.

Figure 1 shows inside elevation a metallic thermometer, partially broken away, to more clearly illustrate the present invention; and

Fig. 2, a top view-of thethermometer, the dotted line representing the perforated supporting-strip.

Theinclosing-case a is of usual size and shape to contain all the co-operating parts within it, thesaid case having a glass face-plate, a. The dial a preferably of sufficient diameter to snugly fit the inclosing-case, is provided upon its under side with suitable supporting-blocks, a a, which support the brackets which serve as bearings for the shaft to which the thermal coil 15 is attached. A pointer, p,

is fixed to an arbor, p, turning in the dial,

the said arbor carrying a pinion, (not shown,) which is engaged by the teeth of a sector, 8, connected with the thermal coil, 'so that as the said coil is moved by changes in the temperature the pointerp will be moved over the dial. The dial a thus supporting all the co-operating parts, is placed within the inclosingcase a and supported by the perforated sup porting-strip c. The strip 0 is preferably made or" sheet-tin of suitable width and length to be bent and fitted into the inclosing-case and The supporting-strip, as herein described,

is very cheap, and, being simply placed within the inclosing-case and not fastened, no labor is involved.

I am aware that the dial-plate of a metallic thermometer has been supported by means secured to and projecting inward from the case, but with such means a fastening is employed, which shows through the walls of the case, which, besides being expensive, is objectionable as'unsightly, and if the interior of the case is provided with a shoulder to support the dial the case must be very thick, and in such instance the thermal coil will not be as sensitive as necessary.

'I claim-- In a thermometer, the pointer, the thermal strip, and connecting means actuated by the thermal strip for moving the pointer, and the dial supporting all the said co-operating parts, an ihclosingcase for the dial and the parts supported by it, combined with a perforated supporting-strip, c, placed loosely within the to this specification in the presence of two subinclosing-case upon which the dial rests, the scribing witnesses. width of such supporting-strip being sufficient to retain all the co-operating parts free from THOMAS SHEPHERD 5 contact with the said inclosing-case, all sub- Witnesses:

stantially as described. GEO. HOLMAN.

In testimony whereof I have signed my name THEODORE HOLMAN.

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