US618260A - white - Google Patents

Description

No. 6l8,260. Patented Ian. 24, I899. C. P. WHITE.

OVEN THERMOMETEB.

(Application filed Aug. 18, 1898.)

3 Sheets$heet I.

(No Model.)

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OVEN THERIOIIETER.

(Application mod Aug. 18, 1898.)

(No Model.) 3 Sheets-Sheet 2.

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OVEN THERMOMETER.

(Application filed Aug. 18, 1898.) (No Model.) 3 Sheets-Sheet 3.

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time 7 STATES PATENT Trice.

CHARLES P. WHITE, OF TAUNTON, MASSACHUSETTS, ASSIGNOR TO THE IVHITE WVARNER COMPANY, OF SAME PLACE.

OVEN-THERMOMETER.

SPECIFICATION forming part of Letters Patent No. 618,260, dated January 24, 1899.

Application filed August 18,1898. Serial No. 688,855. (No model.)

chusetts, have invented certain new and useful Improvements in Oven-Thermometers, of which the following is a specification.

My invention relates to a thermometer for use in combination with an oven or other closed chamber which is to be heated to a high degree to indicate to an observer 0n the outside the temperature within the oven or chamber.

The several features of my invention will now be fully described and will be particularly pointed out in the claims at the end of the specification.

In the drawings, Figure 1 is a front elevation, partly in section, of my oven-thermometer detached from the oven-door. Fig. 2 is a plan of the under side of Fig. 1, partly in section. Fig. 3 is a section on line 3 3 of Fig. 2. Fig. 4 is a cross-section on line at at of Fig. 1, showing also a section of the oven-door.

Inclosed in a metal tube 1, preferably of brass or other metal which is highly expansive when heated, are two springs 2, which lie lengthwise of the tube, being spread apart at the middle and converging toward each otherat the ends. At one end the said springs are secured to the washer 3, which is fixed in the end of the tube. At their other end the said springs are entered between the converging sides A of the sliding box 6, the ends of the springs abutting against the head of said box. In the end of the tube is a washer '7, through which passes a screw 8, which bears against the head of the sliding box 6. By setting up the screw 8 the sliding box 6 is pushed forward in the tube, and the springs 2 are thereby adjusted to the proper tension for use. By turning back the screw the tension is reduced.

The tube 1 is clamped between the arms 12, which project rearwardly from the dial-box 11 and the yoke 9, which is secured by screws 10 to the back of said dial-box. The tube 1 is prevented from turning by a lug 13, which projects from the inside of the yoke 9 into a hole in the side of said tube. Projecting from the side of one of the springs 2 is a bracket 14, which forms a bearing for the arbor 15. Said arbor passes through the dial-box and carries on its outer end an index-hand 16. On the arbor 15 is a pinion 17, which engages with a rack 18, projecting from the spring 2 other than the one to which the bracket 14 is attached. The dial-box 11 is secured to the oven-door 19, through which is an opening to expose the dial 20, which closes said opening. On the inside of the oven-door is a flange 21, which helps to support the dial-box and is cut away at the upper part, so that the index-hand 10, which is longer than the radius of the opening for the dial, may have freedom to move between the door and the dial-box. The portion of the dial which the hand traverses is graduated to degrees of heat. When the oven is heated, the tube 1 is correspondingly heated and expands in length, so that the sliding box can accordingly yield somewhat to the pressure of the springs, thus reducing the tension. As the tension is reduced the springs tend to assume a more straight form and draw nearer together at the middle portions. In so doing the rack 18 is moved also, thereby turning the pinion l7, and the index-hand will indicate on the dial the de gree of temperature in the oven.

The form of support for the tube and its mode of attachment to the oven-door may be varied without departing from my invention, the main features of which are the expansion-tube, the springs, and the mechanism actuated thereby to turn the arbor on which the index-hand is mounted.

What I claim as my invention is- 1. In an oven-thermometer an expansive metal tube, two springs in said tube lengthwise thereof spread apart at their middle portions and converging toward the ends, the ends of the springs at one end of the tube being secured against spreading, a sliding box at the other end of the tube which receives the ends of said springs, a rack projecting from the inner wall of one of said springs, a bracket projecting from the inner wall of the second of said springs, an arbor having its bearings in said bracket, an index-hand carried by said arbor, and a pinion on said arbor which engages with said rack whereby when the tube is expanded by heat the springs will be drawn toward each other at the middle thereby turning the arbor and index-hand, substantially as described.

2. An oven-thermometer having a tubular casing which is expansible by heat, two springs in said tube lengthwise thereof spread apart at their middle portions and converging toward the ends, the ends of the springs at one end of the tube being secured against spreading, a sliding box at the other end of the tube which receives the ends of said springs and prevents spreading thereof,a rack projecting from the inner wall of one of said springs, a bracket projecting from the inner wall of the second of said springs, an arbor having its bearing in said bracket and a pinion on said arbor which engages with said rack whereby when the tube is expanded by heat the springs will be drawn toward each other thereby turning the arbor, an indexhand on the end of said arbor, a dial therefor, and a frame to which said tubular casing is secured, in combination with an oven-door to which said frame is secured, the oven-door having a reading-opening for the dial, and having on the inside of the door around the said openinga flange which partially supports the thermometer-frame and leaves a space between the door and the dial-box for the movement of the index-hand, substantially as described.

3. In an oven-thermometer, an expansive tubular casing, two springs lengthwise of said casing spread apart at their middle portions and converging toward their ends, means for preventing the springs from spreading apart at the ends so that when the tube is expanded the springs will be drawn toward each other at their middle portions, an arbor carrying an index hand and mechanism which is actuated by the movement of the springs to turn the said arbor and index-hand, substantially as described.

I. In an oven-thermometer, an expansive tubular casin g, two springs lengthwise of said casing spread apart at their middle portions and converging toward their ends, means for preventing the springs from spreading apart at the ends so that when the tube is expanded the springs will be drawn toward each other at their middle portions, an arbor carrying an index-hand, mechanism which is actuated by the movement of the springs to turn the arbor and index-hand, a sliding box in said tubular casing at one end thereof which receives the ends of the springs, and a regulating-screw in the tube acting on a sliding box whereby the proper tension may be given to the springs, substantially as described.

In testimony whereof I have affixed my signature in presence of two witnesses.

CHARLES P. W HITE.

Witnesses:

\VILLIAM A. COPELAND, OSCAR F. HILL.

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