US2012618A - Electric heating - Google Patents

Description

Aug. 27, 1935. R. H. PARK ELEQTRIC HEATING Filed Dec. 12, 1931 5 Sheets-Sheet 1 I Mari Aug. 27, 1935. I R. H. PARK 2,012,618

ELECTRIC HEATING L Filed Dad. 12; 19s1-- 5 Sheets-Sheet z 2 ,6 446- /7 5 2111;111:111 EiQIIIIIQQl I112i}; (Q2 E 5 gm T x m mix '@lm@fl@ m l@ 5 I 6/ "A" 1 Wu lnvezafiav:

Aug. 27,1935 R. H. PARK 2,012,613

I ELECTRIC HEATING Filed Dem-12, 19:51 5 Sheets-Shee t 4 u 27, 1935'; R. H. PARK 2,012,618

ELECTRIC HEATING Filed Dec. 12, 1931 5 Sheets-Sheet 5 Patented Aug. 27, 1935 UNITED STATES PATENT OFFICE 14 Claims.

This invention relates to electric heating, and the. object is to provide an improved mechanism wherein the object to be heated, forexample, a

" liquidecontaining vessel, is included as a part of a 6 circuit of high amperage and low voltage.

My invention will be well understood by reference to the following description of the specific embodiment thereof shown by way of example in the accompanying drawings, wherein:-

Fig. l is a plan view of a stove such as would be used for domestic cooking purposes;

Fig. 2 is a section through the top of the stove and the vessel thereon taken on the line 2- -2 of Fig. 1 and showingyparts beneath in elevation;

Fig. 3 is a similanview of the parts shown in Fig. 2 asseen from the left of that figure.

Fig. 4 shows certain parts of Fig. 2 dissociated from adjacent'mechanism;

Fig. 5 is a detailed section on an enlarged scale on theline 5-'5 of Fig. 3;

Fig. 6 is a section on the line 66 of Fig. 3;

Fig. 7 is a section on an enlarged scale on the line |l of Fig. 6; and

Fig. 8 is a wiring diagram.

Electric heating appliances for cooking purposes are commonly used wherein the heat is derived from a resistance wire heated to incandescence.

, While such heating elements are satisfactory for baking, broiling and the like, they are slow and uneconomical for such operations as boiling, and in' the construction about to be described (see Fig. 8) a liquid containing vessel 9, such as a saucepan, is included as a part of a circuit ii of high amperage and low voltage which may be the secondary circuit of the transformer ll, of which they primary coils l5 may be energized from a source of relatively high voltage, such, for example, as

the ordinary 110 volt electric lighting mains. A

current of high heating capacity is thus passed directly through the pan, heating the liquid therein rapidly and efilciently. To exclude current from the contents of the pan with possible electrolytic action thereon I prefer to provide the pan with an enamel lining It. The bottom of the saucepan 9 may be provided with downwardly projecting, prong-like contacts '|'I which may be firmly engaged by clamping jaws I8 (see Fig. 2) to connect the pan in the circuit.

Means, preferably power means, are utilized to close the clamps and, after they are closed, to initiate the current supply. When the heating operationis completed, thesupply circuit is preferably opened and then the clamps are released. I will first describe the operation in a general way with reference to the diagram, Fig. 8, and then,

with reference to the other figures, the mechanical construction herein shown-by way of example. Referring, therefore, to Fig. 8, the pan 9 being placed in position with the contacts between the open jaws I! of the clamps to permit the latter to be closed thereon, theheating operation may be started by moving the double pole switch 2| to the left in the figure to engage the contact 23. Current is thus supplied through wire 24 and bridge 25 to an electric motor 21 which by mechanical means (not shown in the diagram) closes the clamps l9. When the clamps are closed, movement of the motor initiates the flow of ourrent to the transformer i3, and herein a cam 29 driven by the motor closes switch 3| energizing the solenoid II. The core of this solenoid rising causes bridge I! to close the circuit to the primary II of the transformer. It also lifts bridge 25, breaking the circuit to motor 21, stopping the same, and lifts bridge 31 in the conductor leading to,a motor magnet 39 so that the latter cannot receive current while the solenoid is energized. The number of turns in the primary and consequentiy the rate of heating may be controlled in the usual manner by a controlling switch 4|.

When the heating is completed, switch 2| is moved over into contact with the pole 43. By this means the circuit of solenoid 33 is broken and bridge 3! falls, interrupting the current to the primary ll. As. bridge 31 closes, current fiows through pole 43 to the motor magnet 39, the operation of which provides by means hereinafter to be described for the release of clamps l9 and also for the reopening of switch 3|.

Referringnow to Fig. 2, the contacts are there shown as passing through suitable openings 45 (see Fig. l) in the stove top 41 beneath which openings the clamping jaws IO are arranged. These jaws may take the form shown in Fig. 5 and may comprise suitable contact blocks 49 mounted between side members 5| pivotally mounted on rock shafts 53 and yieldably connected thereto by means of the strong torsional sprlhgs 55 which yield when the blocks are pressed against the contacts H. The block 9 may be laterally extended as shown in Fig. 3 to provide for connection of the flexible conductor 51 thereto. The side surface of the block 49 makes the electric contact and I preferably provide an insulating covering 59 over the top face of the law to avoid any possible inefficient closing of the circuit by engagement of the bottoms of the contacts II with the tops of the jaws.

Referring to Fig. 2. the rock shafts 53 for the pairs of contacts are preferably intergeared by pinions as shown whereby on turning of one shaft the pairs of clamping jaws will open and links 61 forming a toggle which carries at its central pivot a cam follower 69. Movement of this follower upwardly to the position shown in Fig. 2 will cause the clamps to close. The toggle is herein straightened by the cam 1| on cam shaft 13 driven at suitable speed from motor 21 already referred to in the description of the wiring diagram. It will be seen that if the cam 1| is turned from the position shown in Fig. 2, it will engage the follower 69 and gradually raise it to the point there shown, but when the nose of the cam passed the follower, if no other mechanism is provided the follower would be free to fall and the clamps would be opened and released on each revolution of the cam shaft. I therefore provide a member 15, best shown in Fig. 4, having the portion 11 of substantially the same radius as the highest portion of the cam and yieldably connected to the cam 1| by means of spring 19 which normally tends to hold the member 15 rotated clockwise from the position of Fig. 4 with its stop shoulder 8| in contact with pin 83 projecting from the cam and with the part 11 in alignment with the highest or nose portion of the cam. The member 15 is also-provided with a projecting pin 85 adapted to engage a lug 81 on a pivoted arm 89 normally held by means of spring 9| in the position shown in Fig. 4 with lug 81 in the path of pin 85 but which may be depressed by means of the motor magnet 39, as will hereinafter be described. In the operation of the parts, therefore, when the high part of the. cam, the member 15 moving therewith, brings the toggle to the position shown in Fig. 2, pin 85 makes contact with stop 81 and stops further movement of the member 15, the cam, however, continuing to move and tensioning spring '19. The part 11, therefore, remains stationary under the follower 69 and holds the clamps closed even after the nose of the cam 1| passes beyond the follower to the position shown in Fig. 2.

Camshaft 13 may also be provided with a tappet or cam 93 adapted, when the parts reach the position shown in Fig. 2, to operate a snap switch 3| which may be of the type shown in the patent to De Reamer 1,579,082, March 30, 1926, and. unnecessary to illustrate or describe in detail. This switch is here shown as carried on a pivoted arm connected by rod 91 to crank arm 6|. Thus,

8) solenoid 33, initiating the flow of current to the heating element and by the lifting of bridge 25 breakingthe circuit to the motor so that the cam shaft 13 stops in the position shown. When the heating is completed, if the switch 2| is moved to the off position in contact with pole 43, the circuit of the solenoid 33 is broken as before described. The core of solenoid 33 falls and the bridge 35 breaks the circuit to the primary l5 of the transformer. The circuit of motor magnet 39 is closed at 43 and 31, the magnet attracts its armature, pulling down arm 89, releasing the member 15 to spring 19 so that the surface 11 is drawn out from beneath the cam follower, re-

leasing the rock shaft to the action of spring 63 (Fig. 2) and opening the clamps. In this opening movement arm 95 swings downwardly, removing switch 3| from the nose of cam 93 and permitting the same to snap open. This action, while a rapid one, permitting the cooking vessel to be immediately removed, is nevertheless clelayed until after the heating circuit is broken since motor magnet 39 cannot be energized until bridge 31 is closed and bridge 35 opened on deenergizing of the solenoid 33. The possibility of arcing is thus avoided.

Referring again to Fig. 8, I have there shown means to open the heating circuit in case the resistance abnormally rises, as might happen, for instance, when a boiling operation was in question and the pan boiled dry and became red hot. For this purpose I interpose in the circuit of solenoid 33 a safety switch which may comprise a fixed contact 99 with which cooperates a spring blade |8| connected in the circuit by means of a flexible lead I03 and carried by a rocking beam I05 pivoted at I01 and having the spring I09 attached thereto through a suitable lever arm as shown so as to hold the beam tilted either in the closed position of the switch as shown or in the open position when the beam has rocked somewhat clockwise.- A handle III on the beam provides for returning the switch to the closed position shown after it has been opened in the manner about to be described. Opposite ends of the beam are here shown as connected to the cores of coils H3 and H5 respectively, the conjoint action of which on their respective cores controls the position of the beam. Coil H3 is arranged in series in the circuit of the primary coils l5 of the transformer and is so wound as to attract its core with a force proportional to the current (amperage). Coil H5, however, is of high resistance and may be bridged across a portion of the coil l5, conveniently with the addition of a resistor H1, and .acts on its core with a force proportional to the electro-motiveforce or voltage Consequently when the resistance of pan 9 rises, the current demand of the secondwhen the toggle formed by arm 61 is moved tQ- ary falls, current (amperage) in primary l5 deward the position of Fig. 2 to close the clamp arm 6| consequently is swung clockwise and arm 95 is lifted cam 93. I

It will .thus be seen that when switch 2| is moved onto the contact 23 and the motor 21 energiz'ed, cam 1| starts to turn. When it has reached a position about 35 short of that shown in Fig. 2, the highest point of the cam has acted on follower 69-and closed the clamps which are held in thatposition'by the action of the surface 11 as described. Meanwhile switch 3| has been brought into the path of the cam 93, and when the cam shaft reaches the positionshown in Fig. 2, that switch is thrown, energizing (see Fig.

to bring the switch into the path of creases, the electro-motive force increases, and the force of coil H5 overcomes the forceof coil H3, rocking beam I95 clockwise andopening the switch.

It will be seen that the safety switch 99-|0|. the operation of which has just been described,

' is disposed in the lead from pole 23 of switch 2| before conductor 24 branches therefrom and stove its positioning with the contacts l1 presented to openings 45 is'facilitated. The flange H9 is preferably made discontinuous, as shown in Fig. 6, preferably being broken at diametrically opposite points and-the groove is likewise broken (see Figs. 6 and '7) by means of projec- ,t ions I23 adapted to be received in the discontinuities of the flange. The notch in the flange and the sides of this rib 'may similarly be bevelled to facilitate positioning. It will be understood that these notches and ribs facilitate the angular positioning of the pan so that the contacts l1 may easily be passed'through the openings it. These guiding parts are situated at the exterior easily visible and do away with any need of fumbling in placin the pan in position.

In the case of a domestic heating stove, such as shown in Fig. 1, besides the usual baking oven and broiler at I28 I may provide. stations, herein the two shown at the bottom of the figure, constructed asdescrlbed for boiling or like operations involving the heating of relatively large quantities of material, and also stations such as those shown at the rear of the flgure with resistance heating elements I21 of customary type adapted to be heated by the ordinary current. I prefer to arrange these heating elements in such manner that openings 45a and grooves .lIla

similar to theopenings l5 and grooves III are provided in the stove top. This permits utensils primarily adapted for use for boiling purposes on the stations in front to be placed on or used in connection with the other heating elements. It will be understood that the openings a are or may be dummies with no mechanism such as that shown in Fig. 2 beneath them.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive; reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

1. An electric heating device comprising a line having clamps for engaging contacts on a device to be heated to include the same in an electric circuit, means to supply current of high amperage and low voltage to said line, a manually operable controlling switch, a motor and a relay having circuits passing through one pole of the switch, a second switch in the relay circuit, mechanical means operated by the motor for closmg the clamps, means operated by the motor for closing the second switch, a second motor having aoircuit passing through another pole of the controlling switch, means operated by said second motor for releasing the clamps, switches operated by said relay for the current supply to the heater and for the circuits of said motors, the latter being open when the flrst is closed and vice versa. 1

2. In an electric heating device of the kind described, intergeared rock shafts carrying clamping jaws to engage contacts on a vessel, an arm on one of the shafts and a cam to act on the arm to close the jaws.

3. In an electric heating device of the kind described, inter-geared rock shafts carrying clamping jaws to engage contacts on a vessel, an arm on 'one of the shafts, a switch for controlling the supply of current to said clamp, a cam shafthavingbothacamtoactonsaidarm and a cam controlling said switch.

4. In an electric heating device of the class described, intergeared rock shafts carrying clamp jaws, means for normally rotating the same to release the clamps, an arm for rotating the same to close the clamps, a cam for swinging said arm, a support for said arm spring-connected to said cam, and a releasable stop for said support.

5. In a device of the class described, intergeared rock shafts carrying clamp jaws, means for normally rotating the same to release the clamps, an arm for rotating the same to close the clamps, a cam shaft having a cam for swinging the arm, a support for said arm free on the shaft but spring-connected to said cam, a switchoperating cam on the shaft, a switch, a movable support for the. switch connected to the jaws and moving into the path of said latter cam when the jaws close, and a releasable stop for said support.

6. In a device of the kind described, in combination with contact-engaging clamps, means normally tending to open the same, an arm for closing the same, a cam for swinging said arm, a support for said arm spring-connected to said cam, and a releasable stop for said support.

'7. In a device of the kind described, in combination with the contact-engaging clamps, means normally tending to open the same, an

arm for closing the same, a cam shaft having a cam for swinging the arm, a support for said arm free on the shaft but spring-connected to said cam, a switch-operating cam on the shaft, a switch, a movable support for the switch connected to the jaws and moving into the path of said latter cam when the jaws close and a releasable stop for said support.

8. An electric heating device comprising a line having clamps for engaging contacts on a device to be heated to include the same in an electric circuit-means to supply current of high amperage and low voltage to said line, said clamps being normally open when the line is dead whereby said contacts may be freely positioned between the same without impediment, power means for closing the clamps, energy-storing means operated by said power means, and means to release the clamps to the action of said energystoring means for rapidly separating the same.

9. Equipment for electric cooking comprising a self-contained portable vessel adapted to receive material to be heated and having studs projecting exteriorly therefrom, electric heating means incorporated in the vessel for which heating means said studs constitute terminals, a support for the vessel, pairs of relatively movable clamp jaws positioned adjacent the support and connected respectively to opposite sides of a source of electric energy whereby when the pairs are closed on the studs respectively the said heating means forms a part of a circuit extending from one pair to another, said jaws having an open position wherein by a mere movement of superposition ofthe vessel on the supp rt they freely receive the studs between them with clearance between'the parts, and means for closing and opening the jaws and for energizing and deenergizing the circuit interrelated to exclude' prior to opening of the jaws, the closing of the jaws and the deenergization of the circuit being initiated by separate manual operations.

10. Equipment for electric cooking comprising a self-contained portable vessel adapted to receive material to be heated and having studs projecting exteriorly therefrom, electric heating means incorporated in the vessel for which heating means said studs constitute terminals, a support for the vessel, pairs of relatively movable clamp jaws positioned adjacent the support and connected respectively to opposite sides 01' a source of electric energy whereby when the pairs are closed on the studs respectively the said heating means forms a part of a circuit extending from one pair to another, said jaws having an open position wherein by a mere movement of superposition of the vessel on the support they freely receive the studs between them with clearance between the parts, and means responsive to a manually efiected operation for closing the jaws and eiiective only after such closure to permit energization of said circuit and means responsive to an independent manual operation for deenergi'zing the circuit and eifective only after such deenergization to permit opening oi the jaws.

11. Equipment for electric cooking comprising a self-contained portable vessel adapted to receive material to be heated and having studs projecting exteriorly therefrom, electric heating means incorporated in the vessel for which heating means said studs constitute terminals, 9. support for the vessel, pairs of relatively movable clamp jaws positioned adjacent the support and connected respectively to opposite sides of a source of electric energy whereby when the pairs are closed on the studs respectively the said heating means forms a part of a circuit extending from one pair to another, said jaws having an open position wherein by a mere movement 01' superposition of the vessel on the support they freely receive the studs between them with clearance between the parts, and means responsive to independent manual operations respectively ior sequentially closing the jaws and energizing the circuit, and for sequentially deenergizing the circuit and opening the jaws.

12. Equipment for electric cooking comprising a self-contained portable vessel adaptedto receive material to be heated and having studs projecting downwardly therefrom, electric heating means incorporated in the vessel for which heating means said studs constitute terminals, a support for the vessel having openings or relatively large size freely to pass the studs, pairs of relatively movable clamp jaws beneath the openings and connected respectively to opposite sides of a source of electric energy whereby when the pairs are closed on the studs respectively the said heating means forms a part of a circuit extending from one pair to another, said jaws having an open position wherein by a mere movement of superposition of the vessel on the support they ireely receive the studs between them with clearance between the parts, and means responsive to independent manual operations respectively for sequentially closing the jaws and energizing the circuit, and for sequentially deenergizing the circuit and opening the jaws.

13. Equipment for electric heating comprising a self-contained portable vessel adapted to receive material to be heated and having studs projecting downwardly from its bottom, electric heating means incorporated in the vessel for which heating means said studs constitute terminals, a support for the vessel, pairs of relatively movable clamp jaws positioned adjacent the support and connected respectively to opposite sides of a source of electric energy whereby when the pairs are closed on the studs respectively the said heating means forms a part of a circuit extending from one pair to another, said jaws having an open position wherein by a mere movement of superposition of the vessel on the support they freely receive the studs between them with clearance between the parts, cooperating means on the support and vessel respectively for centering and orienting the vessel on said support to facilitate insertion of the studs between the open jaws and manually operable means for closing the jaws and energizing the circuit and also for deenergizing the circuit and opening the jaws. 14. An electric heating device comprising a line having clamps for engaging contacts on a device to be heated to include the same in an electric circuit, means tosupply current of high amperage and low voltage to said line, and means mutually exclusive in their operation foropening and closing the clamps.

. ROBERT H. PARK.

Images