US2235252A - Temperature indicating instrument - Google Patents

Description

March 18, 1941. R. l. BRADLEY TEMPERATURE INDICATING INSTRUMENT Filed Dec. 6, 1938 Patented Mar. 18, 1941 UNITED STATES.

TEMPERATURE INDICATING INSTRUMENT Robert I. Bradley, Belmont, Mass.

Application December 6, 1938, Serial No. 244,202

1 Claim.

This invention relates to temperature-indicating instruments, such as thermometers, and more particularly to thermometers wherein the temperature-determining means is any suitable, preferably linearly-expansive, element or elements, and so mounted that its supporting means or base is particularly adapted to be secured to a window pane, for instance, the window of an automobile, or house, and the expansion element and graduations thereon legible through the window, and if desired, also, through the thermometer base itself.

Of the embodiment of my invention selected for illustration and description, herein:

Fig. 1 is a front elevation, or, when mounted, an inner face View, on an enlarged scale for convenience, as are also all the figures;

Fig. 2, a vertical section on the line 22, Fig. 1, looking in the direction of the arrow;

Fig. 3 shows a modified form of construction, with a cover for the base member;

Fig. 4, a view similar to Fig. 1, embodying a modified construction of temperature-determining means;

Fig. 5, a sectional view on the line 5-5, Fig. 4;

Fig. 6, a side elevation, or edge view, partly broken away, of the composite metal, expansive element.

My novel thermometer, Figs. 1, 2, comprises a base, as a disk I, of any material; as glass, Celluloid or the like, and plain or colored, and of any outline, but preferably circular, and, for convenience, dish-shaped or curvilinear in cross section, and of any convenient size, as three inches in diameter, or more or less if desired.

The inner surface edge 2 of the disk may be ground to ensure that it will cooperate with any suitable cement to provide a tight joint with a transparent pane, as of glass 3, Fig. 5, as in a window, or with a transparent back or cover member 4, as glass, Celluloid or the like, Fig. 3, if it is desired to use the cover member, and with or without a suitable gasket.

The inner surface of the disk, preferably near its circumferential edge, Fig. 1, is provided in any convenient manner with short dashes, or measuring graduations 5, of suitable color, indicating degrees of temperature from 1 F., or any number above or below it, in this case from below F.,

0 to any higher number that is within the contemplated range of use of the instrument, as 110 F., the graduations bein accompanied at intervals by numbers, or other identifying indicia 6, of a suitable color for convenience, painted on or otherwise applied to the disk.

On a stud or other support I, Figs. 1, 2, at the center of the disk, and cemented or otherwise conveniently secured thereto, is secured one end of a curvilinear, expansive thermo coil member 8. In the present instance, Fig. 1 this member 8 5 has one end positioned in a slot 9 in the stud, the walls of the slot being compressed tightly against the end.

This thermo coil member, 8, should be of a material that has a known constant ratio, or coeffil0 cient expansion and contraction, as metal, or preferably, as in the present case, Fig. 6, of two or more metals, which cooperate to produce a dependable constant ratio or coefl'lcient of expansion and contraction, and are therefore reliable exponents of the temperature changes.

The outer end I0 of the expansible coil 8 is bent at, a sharp angle, Fig. l, and twisted approximately at 180 to form an arrow-shaped pointer,

Illa.

In the present case, Fig. 6, the coil member is composed of two metals, as brass and elvinar, and the two thin strips of said metals are compressed, face to face, and fused together.

If the disk is to be mounted upon a transparent as back 4, Fig. 3, the disk is cemented, or otherwise satisfactorily secured around the disk edge thereto by any suitable cement, as cellulose acetate in nature, and the back 4 thereafter suitably mounted upon a glass window, Fig. 3, as by the same or similar cement. Otherwise, the disk I itself is cemented, Fig. 5, directly to the window. A cement commercially known as No. 4713 is satisfactory for this purpose.

For convenience, the inner edge of the disk I may have a strip of said, or otherwise suitable, cement I9 applied thereto, Fig. 2, and permitted to dry. When the disk is to be cemented to the window, the cement is softened by the use of any suitable solvent or thinner, as one commercially 40 identified as No. 3120.

The graduations of the scale 5 are properly calibrated to an accepted standard, so that the pointer Illa, as it travels over the scale, will correctly indicate the temperature outside of the disk, suitable allowance being made for the presence of the disk I, whether the disk is provided with the base 4, or mounted directly upon a window 3.

In Figs. 4, 5, I have shown a modified form of construction, wherein the pointer I 2 is formed as a separate member and inserted through an aperture I3 in the coil outer end. The pointer inner end is pivoted or otherwise fastened to the stud I to rotate thereon. The end of the last turn of ber, a temperature responsive coil secured at one end to the concave face of the base member, a pointer actuated by the opposite end of said coil, temperature graduations on the base member along which the pointer moves, the rim of the 5 base member being adapted to engage against a fiat transparent sheet of material whereby a chamber is formed, the concavity of the base member being of such depth to house the temperature indicating mechanism within the cham- 10 her.

ROBERT I. BRADLEY.

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