US2823638A - Range heat indicator - Google Patents

Description

2,823,638 Patented Feb. 18, .1958

RANGE HEAT INDICATOR Elmo E. Aylor, Galesburg, and Don C. Sevey, Abingdon, Ill., assignors to Midwest Manufacturing Corporation, Galesburg, 111., a corporation of Illinois Application June 13, 1956, Serial No. 591,208

7 Claims. (Cl. 116-124) This invention relates generally to an arrangement for giving a visual indication of the heat setting of a heating unit, and is particularly directed to such an indicator for electrical cooking apparatus, such as an electric range.

Commonly in electrical cooking equipment, such as ranges, fry pans and the like, the heat setting of the cooking element is under the control of a thermostat, which in turn is under the control of a manually operated device, such as a rotatable control knob. While the control knob setting in such equipment usually tells the temperature for which the heating element is set, it is advantageous to provide an auxiliary visual indicator which will more strikingly call to the operators attention the heat setting of the equipment. The present invention is directed to such a visual indicator.

It is an object of the present invention to provide on a heating apparatus a novel arrangement for visually indicating its heat setting.

It is also an object of this invention to provide on electrical cooking apparatus a novel visual indicator arranged to effectively call to the users notice the heat setting of the apparatus.

Another object of this invention is to provide a novel visual heat-setting indicator for electrical cooking apparatus which is of simplified and rugged construction which lends itself to economy of manufacture.

Other and further objects and advantages of the present invention will be apparent from the following description of a preferred embodiment thereof applied to an electric range. This preferred embodiment includes a stationary lamp positioned to direct a light beam toward the control knob for the heating unit and a movable plate between the lamp and the control knob which presents an aperture through which the light passes to the control knob. The spacing of this plate from the lamp is determined by the setting of the control knob and the size of the light spot visible on the control knob is correspondingly varied so as to give a high noticeable visual indication of the heat setting.

In the drawings:

Figure 1 is a perspective view, with parts broken away for clarity, showing the present assembly viewed from the back of the control knob; and

Figure 2 is a longitudinal section through the Figure l assembly.

Referring to the drawings, a physical support forthe heat control and indicator in the present invention is in the form of a sheet metal bracket 10 which has its front wall 11 suitably fastened to the splash-back panel 12 of an electric range. The rearwardly extending bottom wall 13 of the bracket supports the housing 14 of a contop burner on the range. The'adjustable portion of the control is coupled to a rotary stem 15, which projects through the housing 14 and up beyond the bottom wall 13 of the supporting bracket. A bevel gear 16 is suitably aflixed to stem 15, such that turning of this gear causes the control setting to be changed accordingly.

As shown in Fig. 2, the splash-back panel 12 is formed with a forwardly projecting annular flange 12011 which defines a circular opening. The bracket front wall 11 has a forwardly and rearwardly projecting annular flange 11a snugly received in this opening in the splash-back panel and defining a circular opening 11b.

A manually rotatable control knob 17 is positioned at the front of the splash-back panel 12. The control knob is mounted on a tubular outer sleeve 18 by means of internal splines 19 on the control knob received snugly in complementary external grooves on the forward end of sleeve 18. With this arrangement, the sleeve 18 turns as a unit with control knob 17. The sleeve 18 extends back through the splash-back panel 12 and the opening 11b in the front wall 11 of the support bracket. At its rear end the sleeve 18 carries an integral bevel gear 20, which meshes with the bevel gear 16 for the control. Thus, when the control knob 17 is turned to a particular angular position the setting of the control is adjusted accordingly.

Adjacent its front end, which is disposed within the axial opening in control knob 17, the outer sleeve 18 carries a metal retaining ring 21. One end of a compression coil spring 22 abuts against this ring. The other end of this spring abuts against the front end of a hollow inner sleeve 23. Sleeve 23 is keyed to sleeve 18 by means of an integral longitudinal spline 24 on the top of sleeve 23, which is received in a complementary longitudinal internal groove 25 in sleeve 18. The back end of sleeve 23 presents a cam surface 26 which is biased by spring 22 into engagement with the cylindrical periphery of the hub 16a of bevel gear 16.

A lamp bulb 27 is fixedly supported by means of a spring clip 28 mounted on the back end of the upper wall 29 of support bracket 10. This bulb is positioned to direct a beam of light onto the transparent front panel 30 of the control knob 17. A shutter arrangement in the form of an opaque plate 31 with a central aperture 32 is provided to control the size of the light beam impinging on the control knob. Plate 31 is secured against an internal transverse annular shoulder 33 on the sleeve 23 by means of a retaining ring 34. Thus, the plate 31 moves toward or away from the lamp bulb 27 to vary correspondingly the size of the light spot on the control knob as the inner sleeve 23 slides within the outer sleeve 18.

In the overall operation of the above described arrangement, when the control knob is in its extreme clockwise position (viewed from the front), the high point 26a of the cam surface on sleeve 23 engages the hub 16a of the gear 16. This positions sleeve 23 at its extreme forward position (against the bias of spring 22) and the apertured plate 31 is remote from the lamp 27; This is the off position of the control knob, with the control at its zero setting. At this time the lamp 27 is extinguished by means of a suitable limit switch (not shown) operated by the control knob.

If it is desired to go through progressively higher heating temperature settings, the control knob 17 is turned counter-clockwise (viewed from the front), the control stem 15 being turned correspondingly through gears 20 and 16 to set the control to establish the cooking temperature called for by the control knob. At the same time, the progressively declining cam surface 26 on the sleeve 23 rides across the gear hub 16a under the influence of the spring 22, and the apertured plate 31 carried by this'sleeve moves toward the'lamp bulb 27. With the lamp-bulb now illuminated, the'size of the light spot impinging on the front of the control knob increases as the plate aperture 32 is positioned progressively closer to the lamp bulb. Thus, the temperature setting to which the control knob is turned determines the size of the light spot visible on the front of knob.

Alternatively, starting from the off position the heat control can be turned rapidly to the full on setting simply by turning the control knob 17 clockwise, so that the steep declining portion 26b of cam surface 26 rides across the hub 16a.

Conversely, when it is desired to turn the heating unit off, the control knob may be turned in either direction.

from the foregoing it will be apparent that the present invention provides an extremely effective, notice-catching arrangement for indicating visually the temperature setting of the heating unit.

While in the foregoing @scription the present invention has' been described with reference to an electric range, it is to be understood that it may be used equally well in other types of cooking equipment, such as electric fry pans, electric roasters, gas ranges, and the like.

Also, while there has been described in detail and illustrated'in the accompanying drawings a particular preferred embodiment of the present invention, it is to be understood that various modifications, omissions and refinements which depart from the disclosed embodiment may be adopted without departing from the spirit and scope. of the present invention.

We claim:

l. In heating apparatus, the combination of adjustable means controlling the heat setting of the apparatus, light source means for producing a light spot visible at the exterior of the apparatus, an apertured member positioned in front of said light source means to control the size of said light spot, and means for adjustably positioning said apertured member toward or away from said light source means in response to the setting of said adjustable means to thereby control the size of said light spot in accordance with the heat setting of the apparatus.

2. In electrical cooking apparatus, the combination of a rheostat for controlling a heating element in said cooking apparatus, a rotatable control knob coupled to said rheostat to determine the setting of the rheostat, a light source positioned behind said control knob to direct a light spot toward the control knob, a plate between the light source and the control knob and having a circular aperture through which the light shines from the light source onto the control knob, and means for adjusting the positionof said plate toward and away from the light source in response to the adjustment of the control knob to thereby control the size of the circular light spot on the control knob in accordance with the rheostat setting.

3. In cooking apparatus, the combination of a manually rotatable control knob for controlling the temperature setting of the apparatus, said control knob having a lighttransmitting portion, a light source positioned to direct a beam of light toward said light-transmitting portion of the control knob, an apertured member positioned between the light source and said light-transmitting portion of the control knob to control the size of the light spot on said light-transmitting portion of the control knob, and means for positioning said apertured member toward or away from said light source in accordance with the angular position of the control knob to thereby control the size of .said light spot in accordance with the temperature setting of the apparatus.

4. In cooking apparatus, the combination of a first bevel gear coupledto the heat control means for the apparatus and presenting a cylindrical hub, a manually rotatable control knobhaving a light-transmitting portion, an outer sleeve coupled to the control knob to turn therewith and carrying a second bevel gear which meshes with said first bevel gear, an inner sleeve coupled to said outer sleeve to turn therewith and slidable axially within said outer sleeve, said inner sleeve carrying a cam surface remote from the control knob, spring means biasing the inner sleeve to position said cam surface in engagement with the periphery of said hub on the first bevel gear, a lamp bulb fixedly positioned within said inner sleeve to direct a beam of light toward said light-transmitting portion of the control knob, and an opaque plate carried by the inner sleeve and positioned to intercept said beam of light, said plate presenting an aperture which passes light from said bulb to said light-transmitting portion of the control knob to produce a visible light spot on the control knob whose size is determined by the spacing of said opaque plate from the bulb.

5. In cooking apparatus having an adjustable heat control means having a portion with a peripheral surface thereon, the combination of a manually rotatable control knob having a light-transmitting portion and coupled to the heat control means to determine the latters setting, a sleeve coupled to the control knob to turn therewith and slidable axially toward and away from said light-transmitting portion of the control knob, said sleeve carrying a follower surface remote from said light-transmitting portion of the control knob, spring means biasing the sleeve axially to position said follower surface in engagement with said peripheral surface on the heat control means, one of said surfaces being a cam surface so that rotation of the control knob causes the inner sleeve to be displaced axially toward or away from said light-tran mitting portion of the control knob, a lamp fixedly positioned to direct a beam of light toward said light-transmitting portion of the control knob, and an opaque member carried by the inner sleeve to move axially therewith, said opaque member being positioned between said lamp and said light-transmitting portion of the control knob to intercept said beam of light, said opaque member having an aperture which passes light from said lamp to said light-transmitting portion of the control knob to produce a visible light spot on the control knob whose size is determined by the spacing of said opaque memberfrom the lamp.

6. The apparatus of claim 5, wherein said peripheral surface on the heat'control means is a cylindrical surface which extends around an axis perpendicular to the axis of said sleeve, and said follower surface on the sleeve is a cam surface which-faces away from said light-transmitting portion of the control knob and has tangential engagement with said cylindrical peripheral surface on the heat control-means.

7. In cooking apparatus having an adjustable heat control means having a portion with a peripheral surface thereon,.,the combination-of a manually adjustable control member coupled to the heat control means-to determine the latters setting, a light source positioned to produce a beam of light visible at the exterior of the apparatus, an apertured member positioned in front of said light source to control the size of the light spot visible at the exterior of the apparatus, and a follower member carrying said apertured member and slidable toward and away from said light source, said follower member carrying a follower surface which engages said peripheral surface on the heat control means, one of said surfaces being a cam surface so that the adjustment of said control member to adjust the setting of the heat control means also adjusts the apertured memberslidably toward or away from said lightisource to control the size of the lightspot visible at the exterior of the apparatus.

References Cited in the file of this patent UNITED STATES PATENTS 2,424,575 Aves July 29, 1947 2,693,165 Appleman Nov. 2, 1954 2,701,541 Miller Feb. 8 1955

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