Untitled record

Application filed January 21,1890. Serial No. 337,581. (No model.)

To all whom it may concern:

Be it known that I, David G. Cooper, a citizen of the United States, residing atPequabuck, in the county of Litchfield and State 5 of Connecticut, have invented certain new and useful Improvements in Oven-Thermometers, of which the following is a specification.

My invention relates to improvements in r° oven-thermometers; and the principal objects of my improvement are simplicity and economy of construction and general efficiency in use.

In the accompanying drawings, Figure 1 is ¹5 a front elevation of my thermometer, together • with a portion of an oven-door, to which it is applied. Fig. 2 is a plan or edge view of my thermometer with a horizontal section of the portion of the oven-door and the thermom2° eter-hood on the line x x of Fig. 1. Fig. 3 is a front elevation of my thermometer with the bezel-ring and dial removed. Fig. 4 is a horizontal section of my thermometer on line x x of Fig. 1, the screws and index-shaft being P'·' 25 shown in elevation. Fig. 5 is a vertical section of the same on line y y of Fig. 4, the ' index-shaft being shown in elevation. Fig. 6 is a rear elevation of the same with the cap , and movement-plate removed. Fig. 7 is a 3° detached view showing the broad side of the movement-plate. Fig. 8 is a detached view showing the broad side of the main plate. Fig. 9 is an edge view of the movement case or rim. Fig. 10 is a like view of the dial case 35 or rim, and Fig. 11 is a detached view showing the broad side of the rack.

My thermometer is principally designed for use upon the ovens of kitchen stoves and ranges; but it is applicable for use upon any 4° oven or hot-air chamber when it is desirable to indicate the temperature thereof.

In constructing my thermometer I forma principal or main plate A, the middle or body portion of which is substantially in circular 45 form, with.laterally-projecting side lugs 1111 on diametrically-opposite sides, which lugs are perforated, to receive bolts for fastening the complete device in place. Said main plate is also provided with a series of elon50 gated openings 12, arranged in a circle near the outer edge of the plate, which openings are designed to receive the lugs 13, corre sponding in number and position on the movement case or rim B, the same being secured by riveting or heading said lugs. This case 55 or rim B is grooved at its periphery, as shown at 14, and its back is covered by a thin metal cap 15, which fits upon said case or rim snugly, like a box-cover, the flange of the cap being of a width that will reach the groove 14 and 60 its edge is turned into the groove slightly, as shown best in Figs. 2 and 4, to firmly secure said cap upon the case or rim B.

The main plate A is provided with a second series of perforations 16 on a smaller circle 65 to receive correspondingly-arranged lugs. 17 on the edge of the dial case or rim C, which in like manner is secured by riveting or heading said lugs. This dial-case is perforated at two or more points, as at 18, and receives 70 upon its outside a bezel-ring D, which is turned over to form a bead at its front edge, so that when slipped or crowded upon the dial-case and over the dial-glass 19, Figs. 4 and 5, it holds said glass firmly between the 75 bead and the front edge of the dial case or rim. The holes 18 are located at the rear edge of the bezel-ring when the bezel-ring is in place, and portions of the bezel-ring are slightly indented and. pressed into said holes 80 with any suitable punch or set, as shown in Figs. 2 and 5. to firmly hold the sash in place. The main plate A is also provided with a pair of elongated openings 20 to .receive lugs 21 for securing the dial-bridge E in place, to 85 which bridge the dial F is secured by means of suitable rivets or screws 22. The main plate is also provided with a series of round perforations in its middle portion, of which three, as at 23, are to receive the pillars or 90 posts 24 of the movement-frame, and the other two 25 and 26 are to receive bushings 30, respectively, for the index-shaft 27 and the shaft 28 of the segmental rack 29. By the employment of said bushings I am enabled 95 to make the main plate A also serve the function of one of the plates of the movementframe. The other movement-plate _G is secured to the opposite ends of the pillars or posts 24, as shown, and. is provided with holes 100 to constitute bearings for the respective shafts 27 and 28. On the movement-case B, I swage or strike up a little boss or projection 31, which is raised to a point substan2

447,129 tially in the same plane as the rear edge of the movement case or rim B, whereby a central support is formed for the cap 15, which prevents said cap from being pressed against 5 the ends of the shafts of the 'movement. The shaft 27 is provided within the movement case or rim with a pinion 32,and in the dialcase in front of the dial with a pointer or index 33. The shaft 28 is provided with a segio mental rack 29, the teeth of which engage the pinion 32, and is provided at the end opposite the teeth with an adjustable arm 34.

To the inner walls of the movement case or rim B, I secure a semicircular bimetal strip 35, 15 the free end of which is connected by means of the link 3G to the arm 34 of the segmental rack. A bimetal strip, rack, and pinion in a thermometer of themselves are not new and are hereby disclaimed. In addition to these 20 I provide the adjustable arm 34 on the segmental rack, which I first form, substantially as shown in Fig. 11, of a metal capable of being bent for the purpose of adjusting the thermometer by bending said arm. While I 25 prefer to employ said adjustable arm as a matter of convenience, it is evident thatother parts of my invention may be employed in connection with a rack having a non-adjustable point for the attachment of the link 36.

Besides the adjustable arm, I add to this thermometer-movementthere-enforcingpiece 37, placing the same between the sides of the case and the end of the strip that is secured thereto, said re-enforcing piece extending 35 along on the outer side of the bimetal strip for a short distance after it begins to separate from the side of the case, thereby strengthening the strip at its junction with the case, and yet leaving it with some elasticity at that point.

During transportation or from any sudden jar the strip is more liable to be in j ured by bending at its junction with the case than at any other point, and by the employment of this re-enforcing piece extending a little beyond 45 the point of attachment this liability to inj ury is prevented. I secure this strip to the rim of the case by means of two rivets 38, and. I place a second re-enforcing piece 39 on the inner side of the strip and pass said rivets through the whole. This second re-enforcing piece, or “ Washer,” as it may be termed, has the end that faces the body of the strip curved outwardly a little, as shown in Fig. 6, so as to allow free movement of the strip, and 55 thereby do away with any angular bearingpoint of the strip. I arrange the shaft 28 of the rack 29 centrally between two of the pillar-posts 23, thereby making said pillar-posts serve as stops to limit the movement of the 6c rack and prevent it from ever being turned in either direction far enough to disengage its teeth from the pin^;on 32.

The dial may have any desired figuring or lettering upon it; but I have found in prac65 tice that some arbitrary figures—as, for instance, 1 to 12, as in a clock-dial—is more readily understood than figures indicating the heat by degrees according to any standard scale, and therefore I use a dial with twelve figures and a circle divided into sixty 70 degrees without any figure or figures to indicate the degrees Fahrenheit, as in the ordinary thermometer. I also prefer to place the words “ Warm,” “Low heat,” “Baking heat,” and “Very hot”atthe properpoints upon thedial, 75 and to so adjust the thermometer that the pointer stands at twelve o’clock when there is no heat in the oven.

I have now described the thermo meter proper, and will proceed to describe its at- 80 tachment to the oven and some special provisions therefor. For its best working it should be insulated from the oven, and in order to provide such insulation and insure that it shall be properly placed I arrange upon each 85 of the lugs 11 11 a washer 40, of asbestus or other insulating or non-conducting material, and I secure the same thereto by means of clips 44, which are preferably T-shaped, and are secured with the T-head upon one side, 90 and the shank or middle portion extending through the hole in the washer and lug and then clenched upon the opposite side, as shown in Figs. 3, 4, and 6, so that the washers will surely be in the proper place when the ther- 95 mometer is attached to the oven or stove door II. A hole is made in said door large enough to let the dial-case pass through it and project a greater or less distance upon the front of the door, and the thermometer secured by 100 means of bolts 41, passing through the door, and the lugs 11, either with or without the addition of other washers, although it is preferred to place other washers thereon to bring the movement-case well into the oven, which 105 additional washers, as at 42, may be of any suitable material, either non-conducting or otherwise.

Washers may be used in suitable thickness and number to make the front of the dial-ease 110 project only a short distance through the door; but if the room in the oven is wanted, or if for any reason it is desired not to have the thermometer project so far into the oven, a surrounding hood K maybe placed on the 115 front of the door, so as to surround and inclose the dial-case, as shown in Figs. 1 and 2, thereby protecting said case from the external air and at the same time giving an ornamental effect. This hood may be fastened on 120 by the same bolts which secure the thermometer.