US3898430A

US3898430A - Retractable electric range apparatus

Info

Publication number: US3898430A
Application number: US526699A
Authority: US
Inventors: Jr James T Sego; Arless B Noble
Original assignee: INSTANT OFF Inc
Current assignee: INSTANT OFF Inc
Priority date: 1974-11-25
Filing date: 1974-11-25
Publication date: 1975-08-05
Anticipated expiration: 1992-08-05

Abstract

A retractable electric range apparatus with a frame mounted within an opening in the upper surface of an electric stove. At least three vessel supports extend upwardly from the frame and have their upper ends terminating in a common horizontal plane to support a cooking vessel thereon. At least three vertical and circumferentially spaced plungers are slidably received within sleeves which protrude through the frame, each plunger having an upper end which is slotted and a lower end with a cam follower thereon. A substantially horizontal and rotatable disc is resiliently supported beneath the frame, the disc having a peripheral rim extending perpendicularly above the disc. A cam is formed on the rim of the disc by period projections and depressions of the rim upon which the followers of the plungers are engaged. A heating element is supported above and substantially parallel to the frame. A plurality of radial support arms are disposed beneath the heating element for supporting the same, while engaging the upper ends of the plungers. An electrically responsive device is provided to impart rotation to the cam so that when the heating element is activated it is raised into engagement with the bottom of a cooking vessel and lowered from the vessel when the heating element is deactivated.

Description

United States Patent [191 Sego, Jr. et al.

[ RETRACTABLE ELECTRIC RANGE APPARATUS [75] Inventors: James T. Sego, Jr., Tahlequah;

Arless B. Noble, Norman, both of Okla.

[73] Assignee: Instant Off Incorporated,

Tahlequah, Okla.

[22] Filed: Nov. 25, 1974 [21] Appl. No.: 526,699

3,440,406 4/1969 Sego, .lr. 3,578,951 4/1971 lngrao 219/444 3,761,680 9/1973 Ingrao 219/456 Primary Examinervolodymyr Y. Mayewsky Attorney, Agent, or FirmWilliam S. Dorman Aug. 5, 1975 [57] ABSTRACT A retractable electric range apparatus with a frame mounted within an opening in the upper surface of an electric stove. At least three vessel supports extend upwardly from the frame and have their upper ends terminating in a common horizontal plane to support a cooking vessel thereon. At least three vertical and circumferentially spaced plungers are slidably received within sleeves which protrude through the frame, each plunger having an upper end which is slotted and a lower end with a cam follower thereon. A substantially horizontal and rotatable disc is resiliently supported beneath the frame, the disc having a peripheral rim extending perpendicularly above the disc. A cam is formed on the rim of the disc by period projections and depressions of the rim upon which the followers of the plungers are engaged. A heating element is supported above and substantially parallel to the frame. A plurality of radial support arms are disposed beneath the heating element for supporting the same, while engaging the upper ends of the plungers. An electrically responsive device is provided to impart rotation to the cam so that when the heating element is activated it is raised into engagement with the bottom of a cooking vessel and lowered from the vessel when the heating element is deactivated.

8 Claims, 10 Drawing Figures PATENTEU M13 5 SHEET PATENTED AUG 5 I975 SHEET SHEET PATENTED AUG 5l975 RETRACTABLE ELECTRIC RANGE APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improvements in electrical heating elements for cook stoves, and more particularly I to a reciprocal heating element which automatically retracts away from a cooking vessel upon interruption of an electrical current thereto.

2. Description of the Prior Art Methods for removal of electrical heating elements from contact with the bottom of cooking vessels have been shown in prior art. Of particular significance is Fernicola US. Pat. No. 2,810,058 (1957), wherein a single rigid support is used to raise and lower an electric heating element. Such single support is particularly disadvantageous if the heating element is to be in intimate contact with the bottom of a cooking vessel, due to the lack of stability of a single point support. This disadvantage was partially overcome by the Applicants prior patent, Sego US. Pat. No. 3,440,406 (1969), wherein yieldable means for the support of the electrical heating element was provided. However, a further disadvantage as shown in the prior art was the necessity for a substantial clearance beneath the existing stove top to accommodate the retraction mechanisms. The present invention overcomes all of these disadvantages by providing yieldable support means for the electrical heating element thereby insuring intimate contact with a cooking vessel. Additionally, at least three point support is provided for the heating element, thereby increasing the stability of the heating element. Further, space requirements are reduced by use of a circumferential cam about the perpendicular rim of a horizontal disc.

SUMMARY OF THE INVENTION This invention relates to the improvement of a re tractable electric range apparatus wherein yieldable support means are provided for the heating element; increased stability of the heating element is accomplished by use of at least three cam followers for the retraction means; and, the reduction of space requirements beneath the surface ofa stove top is achieved by use of a cam circumferential about the upwardly extending perimeter of a horizontal disc.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a plan view illustrating a retractable electric range apparatus incorporating the present invention;

FIG. 2 is a view along line 22 in FIG. 1;

FIG. 3 is a view similar to FIG. 1, with certain elements removed for clarity, showing details of the rotation means of this invention;

FIG. 4 is a view along line 44 of FIG. 3; FIG. 5A is a modification of the pawl shown in FIG.

FIG. 5B shows the reverse side of the pawl shown in FIG. 4;

FIG. 6 is a top view of a horizontal disc and segmented circuit board employed in the apparatus of the present invention;

FIG. 7 is a view along line 77 in FIG. 6;

FIG. 8 is a top view illustrating a second embodiment of this invention utilizing a different rotative means; and

FIG. 9 is a plan view along line 99 of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2 in detail, there is shown an upper surface 10 of an electric stove of the type having a range opening 11 in the upper surface thereof. A retractable electric range apparatus 12 is supported within the opening of the stove by a frame means 14, later to be described in detail. A trim ring 15 is inserted into the opening 11 of the stove top 10 for appearance and to receive a base means 16 therein. The base means 16 provides support for a drip pan 17 thereabove. At least three vessel supports 18 are fixed to the drip pan 17, the vessel supports 18 projecting upwardly therefrom and having their upper ends 19 terminating in a common horizontal plane for supporting a cooking vessel (not shown) thereon.

A plurality of at least three sleeves 34 protrude through the base means 16. The sleeves 34 are substantially vertical and circumferentially spaced about the base means 16. A plunger 36 is slidably received within each of the sleeves 34. The plunger 36 has a slotted upper end 38 and a lower end with a cam follower 40 thereon.

A substantially horizontal frame 26 is positioned beneath the base means 16. An assembly screw 28 is affixed perpendicularly above and to the frame 26. A center nut 30 is threadedly engaged upon the assembly screw 28. As shown in FIG. 2, the upper end of the cen ter nut 30 terminates in the common horizontal plane with the upper ends 19 of the vessel supports 18, thereby providing additional support for a vessel at the center thereof. The base means 16 is received upon the assembly screw 28 and held against the frame 26 by the center nut 30. An elongated tube 42 is connected below and perpendicular to the frame 26. The upper end of the tube 42 receives the assembly screw 28 therein. A bearing 44 is fixedly secured within the lower end of the tube 42. A retainer 46 is vertically reciprocal within the tube 42. A spring 48 is contained within the tube 42 and separates the retainer 46 from the bearing 44. A threaded tension adjuster 50 passes downward through the retainer 46 and spring 48. A threaded bushing 52 projects upwardly through the bearing 44, and receives the lower end of the threaded tension adjuster 50 therein. A substantially horizontal disc 54 is engaged between the bearing 44 and the bushing 52. A peripheral rim 56 extends substantially perpendicular above the disc 54. A cam 58 is formed on the rim 56 of the disc 54 by periodic projections 60 and depressions 62 of the rim 56. The cam followers 40 of the plungers 36 are engaged upon the cam 58.

A heating element 20 is disposed substantially parallel to the frame means 14 and vertically reciprocal thereabove. A plurality of radial support arms 22 beneath the heating element 20 support the same and are preferably connected thereto by welding or the like. The radial support arms 22 engage the slotted upper ends 38 of the plungers 36 thereby transmitting any elevational change experienced by rotation of the cam 58 to the radial support arms 22 which, in turn, vary the elevation of the heating element 20.

Referring now to FIGS. 3 and 4 in detail, a means for imparting rotation to the disc 54 and the cam 58 is shown. The rotational means is comprised of a cylinder 64 rotatably received on the tube 42 of the frame 26.

The cylinder 64 has an upper portion 66 and a lower portion 68 separated from the upper portion by a peripheral flange or ridge 70, having a hole 72 therein. A first spring 74 is wound about the upper portion of the cylinder 64 with one end 76 thereof being affixed to the horizontal frame 26 and the other end 78 thereof being received within the hole 72 in the ridge 70. This first spring imparts a downward thrust upon the ridge 70, thereby keeping the cylinder 64 positioned downward.

A second spring 80 is wound about the lower portion 68 of the cylinder 64. The second spring 80 has an upper end 82 and a lower end 84 thereon. The upper end 82 of the second spring 80 extends perpendicularly from the cylinder 64. A rotatable arm 86 is mounted on the lower portion 68 of the cylinder 64 and extends perpendicularly from the cylinder. The arm 86 has a hole 88 therein, into which the lower end 84 of the second spring 80 is received. A finger 90 protrudes upwardly from the arm 86. The finger 90 has a hole 92 in its uppermost end. A dashpot 94 is affixed to and beneath the frame 26. A rod 96 projects outwardly from the dashpot 94, and is received within the hole 92 of the finger 90. A pawl 98 is attached to the outer end of the arm 86. A movable guide shoe 112 is attached to the pawl 98, the guide shoe 112 being slidable against the disc 54. A spring 108 disposed about a fulcrum 99 spring-loads the guide shoe 112 into contact with the disc 54.

A plunger type solenoid 100 is mounted beneath the frame 26. A plunger 102 of the solenoid 100 engages the upper end 82 of the second spring 80 to rotate the cylinder 64 and cam 86 when the solenoid is energized. The dashpot 94 serves to dampen the action of the solenoid 100.

An electrical contact means 104 is provided to activate the solenoid 100, and is comprised of a nonconductive circuit board 114 attached to the disc 54. The circuit board 114 has a plurality of segments 116 attached thereto. The segments 116 are electrically conductive and spaced in relationship corresponding to the projections 60 and depressions 62 of the cam 58. A set of brushes 118 contact the segments 116 of the circuit board 114. The brushes 118 are connected to an activation means (not shown) for the heating element 20.

A plurality of ratchet teeth 106 are provided on the disc 54. The ratchet teeth 106 are circumferentially spaced and numerically related to the number of projections 60 and depressions 62 of the cam 58, and are engagable by the pawl 98.

P16. A illustrates a variation of the pawl 98, wherein a movable tooth 110 is pivotally mounted on a pin 109 connected to the arm 86. FIG. 5B illustrates the spring-loading of the movable tooth 110 by means of a spring 111 which is received on the pin 109. One end of the spring 111 engages a second fixed pin 113 on the arm 86 and the other end of the spring engages a projection 115 on the tooth 110.

The spatial relationship of the segments 116 of the circuit board 114 to the ratchet teeth 106 is shown in FIG. 6. A separate tooth 106 and associated segment 116 are provided for each projection 60 and depression 62 of the cam 58.

FIGS. 8 and 9 illustrate a second embodiment of this invention. The electrical contact means 104 has been heretofore described. The rotational means illustrated is comprised of an electric motor 120 having a shaft 122 upon which a gear 124 is affixed. A ring gear 126 is attached to the disc 54 and engages the gear 124 thereon. Of course, in the second embodiment shown in FIGS. 8 and 9, the solenoid, pawl, ratchet teeth, dashpot, first and second springs and associated structure are eliminated.

The cam follower 40 of the plunger 36 is comprised of a concave wheel 41 located within a slot 39 and affixed to the plunger 36 by an axle 43. The wheel 41 is received upon the rim 56 of the disc 54, and rotates about the axle 43 as the cam 58 is rotated.

Operation Electrical power is supplied to the apparatus through a connector 24 and someactivation means (not shown) such as a switch or switches. The arrangement of the activation means (or switches) would be such that power would be supplied to certain of the brushes 118 so that the solenoid (or motor would be actuated momentarily to move the heating element upwardly in the on position and downwardly in the off position of the switch, as will appear hereinafter. For example, in the off position, the plungers 36 would be substantially at their lowermost position, the cam followers engaging the cam 58 within the depressions 62. Upon activation of the heating element 20 (turning to the on position), the solenoid 100 would also be activated, thereby causing the pawl 98 of the rotatable arm 86 to engage a ratchet tooth 106 thereon. Movement of the plunger 102 of the solenoid 100 would impart a rotational motion to the arm 86 about cylinder 64 through the second spring 80. Possible abrupt movement ofthe arm 86 would be dampened by the dashpot 94. The plungers 36 with their associated cam followers 40 would be raised upwardly as the disc 54 and its peripheral cam 58 rotate. The upward elevational change of the plunger 36 would be transmitted to the radial support arms 22 which are engaged in the slotted upper ends 38 of the plungers 36. The heating element 20 being supported upon the radial support arms 22 would reflect the elevational change associated with the cam 58.

The spring 48 would be initially adjusted by the tension adjuster 50 when no cooking vessel was on the apparatus, and when the heating element 20 was at its maximum upward elevation so that the top surface of the heating element would be in a horizontal plane slightly above the common horizontal'plane in which the upper ends 19 of the vessel supports 18 and the center nut 30'reside. Upon placement of a cooking vessel (not shown) upon the top surface of the heating element 20, the heating element would be displaced slightly downward, with a corresponding downward displacement of the plungers 36 being transmitted to the spring 48. The spring 48 being slightly in compression thereby would exert an opposite force tending to cause the heating element 20 to return to its no load position. This would cause the heating element 20 to intimately contact the bottom of a cooking vessel.

The solenoid 100 would be only momentarily activated as power was applied through one set of brushes 118 and theconductive segments 116 corresponding to the depressions 62, or the lowered position of the heating element; rotation of the disc 54.would move the segments 116 beyond the actuated brushes and the solenoid would be deenergized.

Lowering of the heating element would be accomplished opposite to the manner described above. That is, turning the switch or activation means (not shown) to the of position would supply power to the other set of brushes which are now in contact with the segments 116 corresponding to the projections 60 (or raised position of the heating element). The solenoid 100 would again be activated momentarily to rotate the disc 54 until the other set of brushes are beyond the high segments 116 at which time the solenoid 100 would be deenergized.

Rotation using the second embodiment herein would be achieved by the momentary activation of the contact means 104 and the electric motor 120, power being interrupted as the brushes 118 pass beyond the low segments 116 as described above. Lowering would be accomplished also as described above.

What is claimed is:

l. A retractable electric range apparatus for an electric stove of the type having a range opening in the upper surface thereof, comprising a frame means mounted within said opening in fixed position relative to said stove, at least three vessel support means extending upwardly from said frame means and terminating at their upper ends in a common horizontal plane for supporting a vessel thereon, at least three substantially vertical and circumferentially spaced sleeves protruding through said frame means, a plunger slidably received within each of said sleeves, each plunger having an upper end extending above said frame means and having a lower end with a cam follower thereon, a substantially horizontal and rotatable disc resiliently supported from beneath said frame means, said disc having a peripheral rim extending substantially perpendicular above said disc, a cam formed on said rim of said disc by periodic projections and depressions of said rim, said followers by said plungers engaging said cam, an electric heating element substantially parallel to said frame means and located thereabove, a plurality of radial support arms beneath said heating element and supporting the same, said radial support arms engaging the upper ends of said plungers, and rotational means responsive to the activation of said heating element for causing rotation of said cam to raise said heating element into engagement with said vessel when said heating element is activated and for causing rotation of said cam to lower said heating element away from said vessel when said heating element is deactivated.

2. A retractable electric range apparatus as set forth in claim 1 wherein said frame means comprises a substantially horizontal frame, an assembly screw perpendicularly affixed above said frame, a center nut threadedly engaged upon said assembly screw, a base means received upon said assembly screw and affixed thereto by said center nut, said base means engaging said stove in the region of said opening, wherein said spaced sleeves protrude through said base means, wherein each plunger is slotted at its upper end, wherein said disc is resiliently supported from said frame means by an elongated tube connected below and perpendicular to said frame, the upper end of said tube receiving said assembly screw therein, a bearing within the lowermost end of said tube, a retainer above said bearing, said retainer being vertically reciprocal within said tube, a spring within said tube between said retainer and said bearing, a threaded tension adjuster passing downward through said bearing and being threadedly engaged 6 upon said tension adjuster, said disc being engaged between said bearing and said bushing, and wherein said radial support arms engage said slotted upper ends of said plungers.

3. A retractable electric range apparatus as set forth in claim 2 wherein the upper end of said center nut terminates in said common horizontal plane and constitutes one of the vessel support means.

4. A retractable electric range apparatus as set forth in claim 2 wherein said rotational means is comprised of a cylinder concentric about said tube of said frame, said cylinder having an upper and a lower portion thereof, a ridge about said cylinder separating said upper and said lower portions, said ridge having a hole therein, a first spring wound about said upper portion of said cylinder, one end of said first spring being affixed to said horizontal frame and said other end of said first spring being located within said hole in said ridge on said cylinder, a second spring wound about said lower portion of said cylinder, said second spring having an upper and lower end thereof, said upper end of said second spring extending perpendicularly from said cylinder, a rotatable arm mounted on said lower portion of said cylinder, said arm extending perpendicularly from said cylinder, said arm also having a hole therein receiving said lower end of said second spring therein, a finger upwardly protruding from said arm, said finger a hole ahole in its uppermost end, a dashpot affixed beneath said frame, said dashpot having a rod outwardly projecting therefrom, said rod being received within said hole of said finger, a pawl attached to an outer end of said arm, a plunger type solenoid mounted beneath said frame, a plunger of said solenoid engaging said upper end of said spring, electrical contact means to activate said solenoid, a plurality of ratchet teeth on said horizontal disc, said ratchet teeth being circumferentially spaced and being numerically related to the number of the projections and depressions of said cam, said ratchet teeth being engagable by said pawls.

5. A retractable electric range apparatus as set forth in claim 4 wherein each pawl has a spring-loaded tooth thereon, said pawl also having a movable guide shoe attached thereto and slidable against said disc, said ratchet teeth being engagable by said teeth of said pawls.

6. A retractable electric range apparatus as set forth in claim 4 wherein said electrical contact means is comprised of a non-conductive circuit board attached to said disc with a plurality of segments attached to said board, said segments of said circuit board being electrically conductive and being spaced in relationship to said projections and depressions of said cam, brushes contacting said segments of said circuit board, said brushes being connected to said activation means for said heating element.

7. A retractable electric range apparatus as set forth in claim 2 wherein said rotational means is comprised of an electric motor mounted beneath said frame, said motor having a shaft therethrough, a gear affixed upon said shaft of said motor, a ring gear affixed upon said disc, said gear on said electric motor engaging said ring gear, electrical contact means to activate said electric motor.

8. A retractable electric range apparatus as set forth in claim 7 wherein said electrical contact means is comprised of a non-conductive circuit board attached to 7 8 said disc and having a plurality of segments attached contacting said segments of said circuit board, said thereto, said segments of said circuit board being elecbrushes being connected to said activation means for trically conductive and being spaced in relationship to said heating element. said projections and depressions of said cam, brushes

Claims

1. A retractable electric range apparatus for an electric stove of the type having a range opening in the upper surface thereof, comprising a frame means mounted within said opening in fixed position relative to said stove, at least three vessel support means extending upwardly from said frame means and terminating at their upper ends in a common horizontal plane for supporting a vessel thereon, at least three substantially vertical and circumferentially spaced sleeves protruding through said frame means, a plunger slidably received within each of said sleeves, each plunger having an upper end extending above said frame means and having a lower end with a cam follower thereon, a substantially horizontal and rotatable disc resiliently supported from beneath said frame means, said disc having a peripheral rim extending substantially perpendicular above said disc, a cam formed on said rim of said disc by periodic projections and depressions of said rim, said followers by said plungers engaging said cam, an electric heating element substantially parallel to said frame means and located thereabove, a plurality of radial support arms beneath said heating element and supporting the same, said radial support arms engaging the upper ends of said plungers, and rotational means responsive to the activation of said heating element for causing rotation of said cam to raise said heating element into engagement with said vessel when said heating element is activated and for causing rotation of said cam to lower said heating element away from said vessel when said heating element is deactivated.

2. A retractable electric range apparatus as set forth in claim 1 wherein said frame means comprises a substantially horizontal frame, an assembly screw perpendicularly affixed above said frame, a center nut threadedly engaged upon said assembly screw, a base means received upon said assembly screw and affixed thereto by said center nut, said base means engaging said stove in the region of said opening, wherein said spaced sleeves protrude through said base means, wherein each plunger is slotted at its upper end, wherein said disc is resiliently supported from said frame means by an elongated tube connected below and perpendicular to said frame, the upper end of said tube receiving said assembly screw therein, a bearing within the lowermost end of said tube, a retainer above said bearing, said retainer being vertically reciprocal within said tube, a spring within said tube between said retainer and said bearing, a threaded tension adjuster passing downward through said bearing and being threadedly engaged upon said tension adjuster, said disc being engaged between said bearing and said bushing, and wherein said radial support arms engage said slotted upper ends of said plungers.

8. A retractable electric range apparatus as set forth in claim 7 wherein said electrical contact means is comprised of a non-conductive circuit board attached to said disc and having a plurality of segments attached thereto, said segments of said circuit board being electrically conductive and being spaced in relationship to said projections and depressions of said cam, brushes contacting said segments of said circuit board, said brushes being connected to said activation means for said heating element.