US2357225A - Electrical switch - Google Patents

Description

*Aug 29 1944- s. .1. RoE'scH ErAL 2,357,225

ELECTRICAL SWITCH Filed March 4, 1942 6 Sheets-Sheet 2 if o o o o o Z m 4f' 5 34 C "1 I 4S Aug. 29, 1944.

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S. J. ROESCH ET AL ELECTRICAL SWITCH Filed March 1942 5 Shee'LS--Sheel 3 Aug- 29, 1944' s. J. RoEscH ETAL 2,357,225

ELECTRICAL SWITCH Filed March 4, 1942 6 Sheets-Sheet 4 Patented Aug. 29, 1944 ass'tzzs ELECTRICAL SWITCH V Stephen J. Roesch and Joseph W. Myers, Philadelphia, Pa., assignors to Proctor & Schwartz, Inc., Philadelphia., Pa., a corporation of Pennsylvania Application March 4', 1942, Serial N0. 433,394

(Cl. 20G-4) 18 Claims.

for control purposes in any instance where it is capable of use. However, the invention is,directed particularly to the control of electric ranges and it will be described with reference to this specific application.

The objects or purposes of the invention, as

well as certain illustrative forms thereof, may be more clearly understood by first considering certain recently developed features of the electric range art with which the present invention is particularly concerned. ,To impart to an electric range unit a speed of initial heating comparable to that of a gas unit, it has been found desir. able to provide suitable flashing means for greatly increasing the energization of the electric range unit until the desired temperature level has been reached and then automatically restoring the normal energization of the unit. flashing operation is performed by switching circuit connections of the range unit. An example The ing, and this may be accomplished byl dropping a portion of the load during the flashing of one of the units. Such a system is disclosed and claimed in the Myers Patent No. 2,213,993, granted September 10, 1940. The load-dropping may be effected by opening one of the supply conductors during the flashing of a unit, thus preventing energization of subsequent units connected to the supply conductors. 'Since it is convenient to use a single switch for the ashing of a unit and the dropping of subsequent load, it is necessary that the switch be in its normal position whenever the associated unit is turned oft If the switch were permitted to be in its flash position when the unit is turned o5, it would be impossible to operate the subsequent units owing to the load dropping feature.

With respect to flashing generally, it is also desirable to provide means for preventing acci of a flashing device of this character is disclosed and claimed in the Myers and Roesch Patent No. 2,207,634, granted July 9, 1940. l

It is also desirable in some instances to provide a manually-adjustable thermostatic Control device for an electric range unit, which device is 'responsive to the temperature of a cooking vessel placed on the unit and operates the unit at the desired temperature level. Such device has been aptly termed a pan control device. A device of. this specific character is also disclosed in the above-mentioned patent, as well as in the Myers and Roesch Patent No. 2,140,479, granted December 13, 1938, which is directed particularly to such a device.

It is also desirable to provide multiple heats 'for an electric range unit in order that the unit may be operated at different temperature levels, such as low, "-medium and high," corresponding to the different levels of operation of a gas unit. Further, it may be desirable to prevent flashing of the range unit at certain temperature levels, i. e. when the multiple heat control switch is operated to certain positions corresponding to said levels. This feature is also disclosed in the first-mentioned Myers and Roesch patent.

With regard to an electric' range as alwhole, it is desirable to prevent overloading due to flashdental or deliberate prolonging of the flash connections, which would result in damage or destruction of the particular heating unit.

In some instances, it is also desirable to employ a heating unit comprising two concentric rings and to provide for operation of one or both `of said rings. as shown generally in the Myers and Roesch Patent No. 2,140,479.

By the present invention, there is provided a novel switch structure which is particularly adapted to meet the above-mentioned requirements of modern developments in the electric range art, and which is capable of a variety of unitary switch which will permit the selection of certain circuit connections and will also permit certain other circuit connections to be established at will irrespective of said first connections, and to provide means for terminating the second connections and reestablishing the first connections at a desirable point in a control cycle. l

A further object of the invention is to provide a unitary switch adapted to permit a plurality of normal circuit connections, selectable at will, and also to permit a special circuit connection at will, and to provide means for terminating said special circuit connection under certain conditions, and for preventing the establishment of said special circuit connection under certain conditions.

Still another object of the invention is to provide a .unitary switch which is adapted to perform the various control functions which are desired in an electric range, as set forth above, said switch being adaptable to operation as a unitary flash and normal energization control switch, as a multi-heat control switch, as a control device for a pan control thermostat, and as a control device for a two-ring unit.

Other objects and features of the invention will be apparent hereinafter.

In the accompanying drawings:

Fig. 1 is a plan view of one form of the switch provided by the invention; Y

Fig. 2 is a side elevation of the same;

Fig. 3 is a bottom view of the switch;

Fig. 4 is a. rear View of the switch;

Fig. 5 is a sectional view taken along line 5-5 ofFig. 1;

Fig. 6 is a sectional view taken along line 5 6 of Fig. 5;

Fig. '7 is a similar sectional view showing the parts in diierent position;

l Fig. 8 is a Perspective view of the mechanism by which the dashing operation and other functions may be performed;

Figs. 9 to 12 are perspective views of certain parts of the device;

Fig. 13 is a fragmentary perspective view of certain parts;

Fig. 14 is a perspectiveview similar to Fig. 8 showing the illustrated mechanism in a diierent condition;

Fig. 15 is a sectional view taken along line I S-IS of Fig. 5;

Fig. 16 is a sectional view taken along, line IE-IB of Fig. 5; y

Fig. 17 is a perspective view of a certain part of the device;

Fig. 18 is an electrical diagram showing the switch in conjunction with a pan control thermostat and the heating unit being controlled;

Figs. 18A and 18B show the positions of the switch contacts at different times;

Fig. 19 is a sectional view similar to Fig. 5 of a different form of the switch;

Fig.Y 2011s a rear view of the same; Fig. 21 is an electrical diagram showing the application of this form of the switch for multiheat and flash control;

Figs. 21A to 21D show the different positions of the switch contacts;

Fig'. 22 is a. plan view of a further form of the switch;

Fig. 231s a side elevational view of the same;

Fig. 24 is a sectional View taken alongline 24-24 of Fig. 22;

Fig. 25 is a sectional view taken along line 25-25 of Fig. 24:

Fig. 26 is a fragmentaryperspective view of apart; and

Fig. '27 is an electrical diagram showing the switch of Figs. 22 to 26 in conjunction with a two-ring heating unit.

Y boit or casing I, made of suitable insulating material, which is enclosed on all but one side. For manufacturing and assembly purposes, the casingl may be split longitudinally, and may comprise two sections 2 and 3 held together by bolts 4. It will .be noted that the contour of the parts 2 and 3 is such as to permit ready and accurate positioning thereof. f

On the top of casing i there are terminal lugs 5 held xedly thereto by virtue of fitting into slots 6, and secured by rivets 1 which may also serve to connect the said lugs electrically to the contact elements within the casing, to be described presently. Cooperatively associated -with the lugs 5 are screws 9, which are adapted to permit connection of .wires from the external circuits to the lugs 5. l

On the bottom of casing I are located lugs 9 ,(see Fig; 3) flxedly positioned by contoured recesses I0 and rivets II which also serve to connect the lugs 9 to certain of the switch elements. Cooperatively associated with the lugs 9 are screws I2 which are adapted to permit connection of Wires from the external circuits lto the lugs 9.

On the front of casing I there is secured a mounting bracket I3, preferably of metal, having suitable provision for attachment to an electric range, so as to hold the switch in proper position on the range. A drip cover I3a (see Figs. 4 and 5) may be provided to protect the terminal lugs 5 from spillage.

At the top of the front of the casing I is 1ocated a pilot light socket is connected mechanically and electrically to an extension I5 on one of the front lugs on the top of casing I. In this socket is shown pilot light IB. A wire I1 completes the electrical connection of the light socket and extends to another lug, as shown.

' On the open side of the casing I, is attached a plate I8 carrying mechanism important to the flashing operation which will be described in detail later. Within casing I (Fig. 6) are located stationary contacts I 9 and flexible contact blades 2D.- These parts are arranged substantially to the right of the casing, as viewed in Figs. 6 and 7, so as to leave suflicient spaceto accommodate the flashing mechanism presently to be described. The contacts I9 are fase tened to the top of the insulated casing and are electrically connected to lugs 5 by the rivets 1. The blades 20 are fastened to the bottom of the casing at 2I and are electrically connected tolugs 9 by rivets II. The blades are arranged so that they are normally biased by their own resilience to make contact with the right hand contacts I9 (left hand contacts in Figs. 6 and 7). Also located within casing I (Fig. 5) are connecting buses such as 22 and 23, which serve to interconnect various blades, contacts and connection lugs.

Located at the front of casing I and formed integrally with the base thereof is a stop 2l. This stop (see Fig. 13) comprises portions 25, 26, and 21 adapted to cooperate with the ange 28 of a cam member 29 (Figs. 10 and 12) car-Q ried by the operating shaft 30. The several portions of stop 24 serve diii'erent purposes, as will be described later. On the front of i cam member 29 are located several radial depressions 32 adapted to act cooperatively with a detent 33 on a. plate 3A (Figs. land v11), so as to snap the switch into various selected positionsand hold it in such positions until other positions are chosen, as will be more apparent later. The plate 34 has its side edges seated in i l shaft 39.

various operations of the shaft. Knob 31 may have suitable indicia (not shown), associated with it to indicate angular positions of the knob in terms of control of an associated heating unit. It will be noted that shaft 39 has a hollow section 39 (Figs. 5 and 10) which is hexagonal in section and thus shaft 30 is adapted to be slidably mounted over a hexagonal cam shaft 39 extending through casing I. At the front end of shaft 30 is a threaded portion 4I! which receive's bolt 4I for securing knob 31 to the shaft. Rotation of the knob on the shaft may be prevented in any known manner, for example by making the engaging portions non-circular or by providing cooperating flat surfaces on said portions.- Within the hollow portion of shaft 35i is placed a compression spring 42 designed to press against the internal shoulder 43 and against lrl'xe head of a bolt 44 extending through A second compression spring 45 presses against the head of bolt 44 and the end of shaft 39.. Thus, springs 42 and-45 tend at all times to urge shaft 30 to its outermost position, as shown in Fig. 5.

Mounted on the rear of casing I and passing through an opening in the rear wall is a bushing 49 having an axial bore 41 to receive an external shaft, as` described further hereinafter, screw 48 serving to fix the shaft in a definite angular relation to the bushing. A portion of bore 41 is threaded to receive the threaded end of bolt 44, and a set screw 49 fixes the position of bushing 46 relative to bolt 44. At its forward end, shaft 39 fits into and is positioned by the hexagonal bore of member 29. .At its rearward end, shaft 39 fits into a circular recess of bushing .45, which serves to .position and center it. The springs 42 and 45 maintain the parts in the positions shown in Fig. 5, and spring 45 maintains the rear end of shaft 39 in frictional engagement with the recessed .end of coupling 45, thus maintaining the relative angular position of shaft 39 and coupling 46 constant, unless ad- Justment is made as described later. In shaft 39 is an opening 59 through which nts a :pin 5I integral with bolt 44. Positioned on shaft 39 are cams 52 adapted to operate blades 29. The rearmost cam 52a is adapted to engaged an extension 53 of the'fiashing mechanism, for a purg pose which will be evident later.

Plate I9 carries the flashing mechanism, which is best shown in Flgs. 8 and 14. Turned ears 54 on plate'II form supports for a shaft 55. n this shaft there are rotatably mounted two L-shaped plates 59 and 51 having turned mounting ears 59 and 59. These plates carry indented insulating pieces' 9|) and 9| shaped to nt blades 29. The insulating piece 9| carried by [plate 51 is adapted to operateonly the first or foremost blade, while the insulating piece 99 operates the other blades in unison. 'A tab 52 on plate 59 is adapted to be engaged by plate 51 in order that the latter may actuate plate 55 in a counter-'clockwise direction, as viewed in Figs. 8 and 14. Attached to plate 51 is a finger 93 which extendsoutwardly from plate 51 substantially parallel to the top .portion thereof and piste se is an up'tumed lug ss to which is pivotally attached a member 69 of an over-center llatching mechanism. The member 55 is pivotally attached to member 51 of the latching mechanism, which in turn is attached rotatably to a lug 68 on plate I9 (see Figs. 6 and 7). Member 81 has a stop rportion 69 adapted to act cooperatively with a stop 10 on plate I8, and a lcam portion 1| adapted vto be engaged by an adjustable latch tripping member 12 in the form of a screw on the end of a bimetallic member 13.

The bimetallic member 13 (see Fig. 2) is attached by rivets 14 to a supporting bracket 15 preferably formed of metal. Bracket 15 is suspported on plate I8 -by means of rivet 19 and porcelain bushings 11. A heating element 18 (see Fig. 1'1) is disposed between insulating sheets 19, preferably of mica, adjacent tothe bimetal member 13. 'I'his heater may be wrapped with asbestos cord 90 (Fig. 2) 'so as to heat and cool substantially similarly to the heating unit being controlled by thel switch, as disclosed in the aforementioned Myers and Roesch Patent No.. 2,207,634. The asbestos cord may also as-l sist in holding the heater and the insulating sheets in place. The heating element is connested to screw terminals 8i which are insulated from plate I8 by the porcelain bushings 11 and the mica sheets 19. Connector strips 92 connect the terminals 8| to the same lugs 5 to which the pilot light I6 is connected.

In operation of the switch to control a heatunit, the shaft is rotated clockwise from its off position (by knob 31) to effect various degrees of normal energization of a heating unit being controlled. The degree of normal energization may be obtained for example by utilization of coupling to operate, by means of ilexof cam member 29 comes into contact with portion 25 of stop 24. During this movement of shaft 39 the conical member 29 engages lip I4 on finger 93, thereby causing plate 51 to rotate about shaft 55 in a counter-clockwise direction as may be seen in Fig. 16. By virtue of tab 52, plate 55 is also rotated simultaneously and is latched into flashing position by latch members 89 and 91, as shown in Fig. 7. When the two .members 59 and 51 are thus rotated.. the blades 29 are moved into contact with the left hand contacts I9. However, the first blade (shown in has a down turned up u adapted to be engaged by the conical portion of member 29. Also on Fig. i6), when thus actuated simlply engages an insulating strip 93 and prevents energization of the unit until knob 31 is released. Thus, so long as the knob 31 is held in, the unit is automatically deenergized. Consequently, it is impossible to flash the unit excessively and thus damage the unit by manually holding the knob 31 in its innermost position. However, when knob 31 is released, the shaft 30. by virtue of spring 42, is forced back to its normal position. Cone 29 is thus disengaged from finger 93, and plate 51 then rotates back into its normal position under the force exerted by the resilience of first contact blade. Thus, the first blade returns to engage its right-hand contact I9, and the unit is energized. The remainder of the blades 29,

however, are maintained in the left-hand position, and in such position make connections to flash the unit'. As the flashing of the unit progresses, the bimetal member 13 is heated and exes, forcing latch tripping member 'l2 into engagement with cam portion 1l (see Fig. rI) and eventually lpushing pivot 84 into a position where its center is above the line of centers of pivots 85 and 86. In this position, the members 66 and 61 can no longer hold member 56 inplace, and it snaps back into its normal position under the force of the resilient spring members 20. Thus, the resilient spring membersi resume their normal energization positions as previously selected by the rotation of knob 31.

If now, it should be attempted to reiiash the unit, it would be found that this could not be done, as the bimetal member 13 is in a position to prevent latch members 65 and 61 from latching plate 56 in position. Since no flash is obtained when the knob 31 is held in its innermost position, and since the plates 56 and 51 now rotate counter-clockwise (as viewed in Figs.

6 and 7) to their normal positions upon the release of knob 31, no flash can take place.

If the switch is actuated to cause a flash of -the unit, and if for some reason it is desired to turn the unit off before the flash is completed, this can be done. Whenever knob 31 is rotated to the off position, the cam' 52a. engages extension 53 of latch member 68, and moves the member out of latching position. It is thus obviousthat whenever the unit is turned olf, any incompleted fiash will be cleared by this means. This is an advantage shouldthe operator unintentionally initiate a flash on the wrong unit. Furthermore, where the switch drops the subsequent load, as will be described presently, this self-clearing means prevents the operator from accidentally leaving the switch in flash position with the associated unit turned oli.

The adjustment screw 12 is provided to allow the duration of the flashing time to be adjusted.A

Itis obvious that the time of flashing will depend on how far the bimetal element 13 has to move before the head of the screw engages portion 1l of member 61. By'adjustment of the screw, its head can be moved closer to or farther from portion 1I, thus eiecting a change in the ashing time.

Referring to the stop 24 (Fig. 13), portion 21 thereof acts vcooperatively with extension 3| (Figs. 10 and 12) on flange 28 to limit the rotation of knob 31, in its selection of normal energization, to an arc'less than 360. Portion 26 of stop 24 acts cooperatively with extension 3l to prevent sliding movement of shaft 30 when the knob 31 is in the off position. This prevents movement of the switch to flash position when it is olf, thereby preventing accidental dropping of the subsequent load. Portion 25 of stop 24 acts cooperatively with fiange 2,8 to limit the sliding movement of shaft during the flashing operation.

In use with a pan control thermostat, l-t may be found necessary atv times to readjust the relative position of the knob 31 and the coupling 46, in order to make the indications of the knob 31 follow correctly the actual values obtained. However, it is undesirable to change the position of knob 31 relative to shaft 39, as the olf position will be determined by the cams on shaft 39, and the posilion of operation of the detent means is determined by shaft 30, which is rotatably fixed with regard to shaft 39. The desired adjustment set and maintained.

. The above-described form lof the switch is adapted for use in conjunction with apan control ldevice and its operation may be more clearly understood with the aid of the electrical diagram of Fg.`18. In that figure there is illustrated diagrammatically at 81 a pan control device of the type disclosed in the above-mentioned Myers application Serial No.1380,3,41, and the heating unit being controlled comprises two main sections 88 and 89 and a low-wattage heating element 90, which are controlled by the pan control device in the manner set forth in the said application. The details of construction of the particular pan control device and its specific mode of operation in conjunction with the particular heating unit are not of importance here and need not be illustrated or described. It suices to state that the particular pan control device diagrammatically illustrated in Fig. 18 is merely illustrative of any device of that general type in which a thermostatic switch controls the heating unit. If desired, a simple form of such device, such as that disclosed in the above-mentioned Patent No. 2,207,634, could be used. From the foregoing description, it will be understood that the pan control device will be adjustable for operation of the heating unit at various temperature levels by means of a flexible shaft connected to the coupling member 46 of the present switch, so that rotation of knob 31 will effect the desired adjustments of the pan control device.

The main sections 88 and 89 of the heating unit are connected .in parallel across the outer conductors of the supply line 9i for r'iash operation and are connected in series across said conductors for normal operation. Fig. 18 shows the po- -been actuated by the flashing mechanism. The

series and parallel connections of the main heating unit sections for normal and :dash operations may readily be seen from Figs. 18A and 18B with reference to Fig. 18. It will be noted that in this instance in which the normal energization of the .heating unit is controlled by means of a pan control device, the contact blades merely serve to turn the heating unit on or off and to effect the ash connections.

In the operation of the switch as thus adapted,

whenever the knob 31 is rotated from the oi position, the contact blades are immediately actuated to turn the heating unit on, the blades then being in the position of I8A. Further rotation of the knob 31 does not change the positions of the blades but adjusts the pan control thermostat through the flexible shaftconnection as above described. I

Whenever itis desired to flash the heating unit, the knob 31 is depressed which causes the contact blades to move to the positions of Fig. 18B. The iiashing operation may be performed irrespective of the position of knob 31 throughout its range of normal energizationcontrol. When the knob is depressed to initiate the dashing operation, the first contact blade is held open, as indicated yby the broken line illustration, by plate 51 until the knob is released, as above described, thereby preventing excessive flash of the heating unit. During the hashing operation, the lowermost supply conductor is opened bythe fourth iontact blade, thereby dropping the subsequent cad.

connected in parallel with the heating element 18 for the flash release thermostat, and' these elements are in series with the heating unit 88--89 during normal operation and in series with one section or leg of the unit during iiash operation. Consequently, during normal operation, the pilot light I8 will glow dimly to show that the unit is in operation, while during ash operation the light will glow brightly as the voltage across the heating element 18 will be twice as much during flash as during normal energization. Of course,

It should be noted that the pilot light ls is care should be exercised'to employ a' pilot light 30 which will withstand the higher voltage during dash operation.

In Figs. 19 and 20, the switch is slightly modied to eil'ect Various degrees of normal energize.- tion by means of the switch cams, as illustrated in Figs. 21 to 21D. In this embodiment, the switch structure is essentially the same as before, but the cams 52 are designed and arranged to eilect the desired function. 'I'nere is also provided a more positive means for retaining the switch in the different control positions.

' At the rear end of shaft 39, there is provided a sleeve 82 corresponding, generally to the coupling sleeve 4l .of `thepreviously-described device, and adapted to rotate with shaft 39. A square cam 83 is afllxed to sleeve 82 by means of a pin 94. An arm 9| is hinged to the rear of casing I at 98 and is urged into engagement with the cam 93 .by a spring 91 which is anchored to the casing at 98.

In the on position ot the switch. one of the nat sides of cam il yis engaged by arm 9.5 so as to establish the oi! position, as illustrated in Fig. 20. When the control knob is rotated to. turn the heating unit on, the cam Il moves the arm I5 against the action of yspring I1 until the next adjacent nat side of ,the cam is engaged by the arm. thereby establishing the low" normal energization position. Further rotation of the knob yestablishes the medium and "high positions of the switch. Since-in this instance the switch must operate through 360, the stop member 2l should be modified accordingly. This merely requires omissionf'ofrportion 21 thereof. The flashing operation is performed in the same manner as previously described.

In the previously described embodiment, flash operation of the switch. in its of! position is preventedl by the coaction o! parts 2l and 3| as hereinbefore described. In the device of Figs. 19 'and 20, ilashODertion of the switch may also be prevented in certain other positions of the switch merely by proper design of the same parts. For example, it may be desired to prevent flash operation at the low position, in which case be designed accordingly. 'I'his would merely require extension of part 2B to prevent longitudinal movement of shaft 30 in the low position as well as in the of! position.

Aside from the above-mentioned differences, the structure illustrated in Figs. 19 and 20 is similar to the first-described embodiment and requires no further description.

Figs. 2l. to 21D illustrate the operation of the modified switch to provide a plurality of heats by variously connecting the heating unit 88-89 to the supply conductors. In Fig. 21, the contact blades are shown in the oil position. In Fig. 21A, the contact blades are shown in the position for low operation, and both sections of the heating unit are connected in series between the uppermost and central conductors, between which there may be a voltage of 115 Vvolts compared to 230 volts across the two outer conductors. In Fig. 21B, the contact blades are shown in the position for medium operation in which section 88 only of the heating unit is connected between the uppermost and central conductors. Fig. 21C shows the position of the contact bladesfor high oper-ation during which both sections of the heating unit are connected in series across the two outer conductors.

Fig. 21D shows the position of the contact blades for iiash operation4 during which both sections ofthe heatng unit are connected in parallel across the two outer conductors and the subsequent load is dropped.

In the utilization of the switch as described immediately above,l three principal cams are required, as shown at 52 in Fig. 19, and of course the cams must be designed to position the contact blades in the manner illustrated in Figs. 2l to 21D for various positions of the control knob 31.

In Figs. 22 to 26, there is illustrated a further modication of the switch structure for the control of a heating unit comprising two concentricl rings, as previously mentioned. In this adaptation of the switch, the flashing operation of the unit is dispensed with and the mechanism previously employed for that purpose is utilized to switch from one ring operation to two ring operation, as will be described in detail presently.

Referring to the mechanical structure of the vplate 51 is modified as shown in Fig. 26 and this plate serves merely to actuate plate Il since. as stated above, the flashing operation is dispensed with.

As before, plate ds latched in its actuated position by the latching means "-61 which is released by cam 52a when the control knob is turned to the oir position. Thus, in this instance, the latching means for plate 5l is rethe parts 2B and 3| of elements 24 and 29 may The operation of this form of the device may best Abe understood with the aid of Fig. 2'? in which there is shown a multi-section heating unit which is intended to be a diagrammatic illustration oi a two ring unit such as above mentioned. The inner ring may comprise sections 99 and illu while the outer ring may comprise sections lill and l02. The pan control device 8l is again employed to vary the normal energization level. In this instance also the heating unit includes auxiliary low wattage sections 03 and iM associated respectively with the inner and outer rings. Here again the speciiic form of the pan control device is not important, and this device could be of the simple form previously mentioned.

When the switch is in oi position, as shownin Fig. 27, the blades are in the position shown. When the control knob is rotated from the oil position, the cams 52 of Fig. 24 cause the rst and last blades to engage their associated contacts,l thereby connecting sections4 99 and illu in series between the two outer conductors of the supply line. The rotation of the control knob also adjusts the pan control device in the manner previously described.

When it is desiredto use the entire heating unit, the control knob is pushed inward and plate 51 moves the other blades into engagement with their associated contacts, thereby connecting sections lili and M32 in parallel with sections 99 and l, respectively. As mentioned above, plate 5l is latched in its actuated position until ythe switch is returned to oi position. Rotation of the control knob, with the entire heating unit energized, adjusts the pan control device to establish any desired operating level of the unit. Referring to the invention generally, it will be seen that the switch is adapted to perform different functions in response to dierent modes of operation. Thus in the iirst two forms described, rotation o the control lsnob conditions the circuit connections of the associated heating unit gior normal energization and also establishes different temperature levels either by adjusting a pan control device or by effecting diierent connections, while depression of the control knob conditions the circuit connections for ash operation. In the last described form of the switch, depression of the control knob conditions the circuit connections for operation of the entire heating unit, while rotation of the knob controls the energization of the unit and also the temperature level.

From the foregoing description, it will be seen that the switch is capable of various uses and is adapted to perform various control functions Moreover, the circuit diagrams illustrated and described are merely illustrative oi some of the uses and adaptations o! the switch and are in no way intended to disclose all oi its possible applications.

' The' illustrated embodiments of the switch are, of course, only illustrative and are not intended to limit the scope of the invention.

We claim: A

l. In an electrical switch, a plurality oi relatively movable ccntacts, means for 'supporting said contacts in mutually cooperative relation.- a manual operating member arranged for rotational and translational movement, means operable by translational movement of said member for effecting relative movement oi said contacts to effect a circuit conditioning function, means conditioning function, means'a operable by transfor vautomatically retaining the relative positions 'I5 of said contacts established by said last means,

and means for releasing said retaining means in response to rotation o! said member to a predetermined position.

2. In an electrical switch, a plurality of relatively movable contacts, means for supporting said contacts in mutually cooperative relation, a manualoperating member arranged ior rotational and translational movement, means operable by translational movement of said member for effecting relative movement of said contacts to eiect a circuit conditioning function, means for automatically retaining the relative positions of said contacts established by said last means, and thermal-responsive means for automatically releasing said retaining means after a timeinterval.

3. In an electrical switch, a plurality oi relatively movable contacts, means for supporting said contacts in mutually cooperative relation, a manual operating member arranged for rotational and translational movement, means operable by translational movement of said member for eiecting relative movement of said .contacts to eiect a circuit conditioning function, means for automatically retaining the relative positions of said contacts established by said last means, thermal responsive means for autically releasingsaid retaining means after a time interval, and means for releasing said retaining means at will in response to rotation oi said member to a predetermined position.

4. In an electrical switch, a plurality of relatively movable contacts, means for supporting said contacts in mutually cooperative relation, a manual operating member, means operable by said member for eiecting relative movement oi said contacts to eiect a circuit conditioning function, and means for preventing the completion of said circuit conditioning function until said member is released.

5. In an electrical switch, a plurality of rel-4 atively movable contacts, means for supporting said contacts in mutually cooperativerelation, a manual operating member arranged for rotational and translational movement, means oper.

able by rotational movement of said member ier actuating said contacts so as to eect a circuit lational movement of said member for actuating said contacts so as to eect a dierent circuit conditioning function, and means iorpreventing the completion of said last-mentioned circuit conditioningiunction until said member is released.

6. In an electrical switch. a plurality of rela.-

tively movable contacts, means for'l supporting said contacts in mutually ccoiierative` relation, a

manual operating member varranged for vrotational and translational vement. means operable by rotational movement oi said member for actuating said contacts so, as to eiect a circuit conditioning function, f: 1f; operable by translational movement o! said said contacts so as' to` eiect a different circuit conditioning function. `and means for preventing translational movement oi said member when it is in a certain position of rotation.

'1. In an electrical switch, a plurality of stati contacts, means for supporting said contacts, a plurality ci movable contacts, means for supporting said movable contacts in cooperative relation with said stationary contacts, a manual operatingV member arranged for rotational and translational movement, means operable by rotational movement of said member for actuating at ember vfor actuating least some of said movable contacts to effect a circuit conditioning function, means operable by translational movement of said member for actuating at least some of said movable contacts to effect a different circuit conditioning function, means for latching the movable contacts in the position to which they are actuated by said last means, and means for releasing said latch means when said member is in a certain position, thereby to terminate the last-mentioned function.

8. In an electrical switch, a plurality of stationary contacts, means for supporting said contacts, a plurality of movable contacts, means for supporting said movable contacts in cooperative relation with said stationary contacts, a manual operating member arranged for rotational and translational movement, means operable by rotational movement of said member for actuating at least some of said movablev contacts to effect a circuit conditioning function, means operable by translational movement of said member for actuating at least some of said movable contacts to effect a different circuit conditioning function, means for latching the movable contacts in the position to which they are actuated by said last means, means for automatically releasing said latch means ,after a time int'erval to terminate the last-mentioned function,'and means for releasing said latch means at will in response to rotation of said member to a predetermined position.

9. In an electrical switch, a plurality of stationary contact elements, means for supporting said elements, a plurality of resilient contact blades, means for supporting said blades in cooperative relation with said elements, a rotatable shaft arranged cooperatively with said blades, means on saidl shaft for actuating predetermined ones of said contact blades to effect at least one circuit conditioningl function, a manual control member for rotating said shaft and movable axially of the shaft, and means operable by the axial movement of said member for'actuating predetermined ones of said contact blades to effect another circuit conditioning function.

l0. In an electrical switch, a plurality of stationary contacts, means for supporting said contacts, a plurality of movable contacts, means for supporting said movable contacts in cooperative relation with said stationary contacts, a rotatable shaft arranged cooperatively with said movable contacts, means operable by said shaft to actuate at least some of said movable contacts and thereby effect a circuit conditioning function, a member movable axially of said shaft, means operable by said member to actuate at least some of said movable contacts to eect a different circuit conditioningfunction, means for latching the movable contacts in the position to which they are actuated by said last means, and means for releasing said latch means when said shaft is in a certain position, thereby to .terminate the lastmentioned function.

, 11. In an electrical switch, a plurality of sta-- tionary contact elements, meansfor supporting said elements, a plurality of resilient contact blades, means for supporting said blades in cooperative relation with said elements, a rotatable shaft -arranged cooperatively with said blades, means on said shaft for actuating predetermined ones of said contact blades to effect at least one circuit conditioning function, a manual control member for rotating said shaft and movable axially of the shaft, means operable by the axial termined ones of said contact blades to effect another circuit conditioning function, means for latching the contact blades in the position to which they are actuated by said last means, and means for automatically releasing said latch means after a time interval to vterminate the last-mentioned function.

12. In an electrical switch, a plurality of sta- -tionary contact elements, means for supporting said elements, a plurality ofY resilient contact blades, means for supporting said blades in cooperative relation with said elements, a rotatable shaft arranged cooperatively with said blades, a plurality of cams on said shaft for actuating predetermined ones of said contact blades to effect at least one circuit conditioning function, a manual control member for rotatingI said shaft and movable axially of the shaft, means operable by the axial movement of said member for actuating predetermined ones of said contact blades to effect another circuit conditioning function, means for latching the contact blades in thel p0- sition to which they are actuated by said last means, and thermal responsive means for automatically releasing said latch means after a time interval to terminate the last-mentioned function.

13. In an electrical switch, a plurality of stationary contact elements, means for supporting said elements, a plurality of resilient contactblades, means for supporting said blades in cooperative relation With said elements, a rotatable shaft arranged cooperatively with said blades, a plurality of cams on said shaftfor actuating predetermined ones of said contact'blades to effect at least one circuit conditioning function, a manual control member for rotating said shaft and movable axially of the shaft, means operable by the axial movement of said member for actuating predetermined ones of said contact blades to effect another circuit conditioning function, means for latchng the contact blades in the position to which theyare actuated by said last means, and means for releasing said latch means when said shaft is in a certain position, thereby to terminate the last-mentioned function.

14. In an electrical switch, a plurality of stationary contact elements, means for supporting said elements, a plurality of resilient contact blades, means for supporting said blades in cooperative relation with said elements, a rotatable shaft arranged cooperatively with said blades, a plurality of cams on said shaft for actuating predetermined ones of said contact blades to effect at least one circuit conditioning function, a manual control member for rotating said shaft and movable axially of the shaft, means operable by the axial movement of said member 1 which they are actuated by said last means, and` movement of said member for actuating predefor actuating predetermined ones of said contact blades to effect another circuit conditioning function, an over-center latching mechanism for latching the contact'blades in the position to cam means on said shaft for releasing said latching mechanism when said shaftis in a certain position, thereby to terminate thelast-mentioned function.

15. In an electrical switch, a plurality of stationary contact elements, means for supporting said elements, a plurality of resilient contact blades, means for supporting said blades in cooperative relation with said elements, a rotatable shaft arranged cooperatively with said blades, a plurality of cams on said shaft for actuating predetermined ones of said contact blades to effect at least one circuit conditioning function, a manual control member for rotating said shaft and movable axially of the shaft, means operable by the axial movement of said member for actuating predetermined ones of said contact blades to eiect another circuit conditioning function, means for latching the contact blades in the position to which they are actuated by said last means, and means for preventing axial movement of said member when said shaft is in a certain position of rotation.

16. In an electrical switch, a plurality of stationary contact elements, means for supporting said elements, a plurality of 1 esilient contact blades, means for supporting said blades in cooperative relation with said elements, a rotatable shaft arranged cooperatively withl said blades, a plurality of cams on said shaft for actuating predetermined ones of said contact blades to effect at least one circuit conditioning function, a manual control member for rotating said shaft and .movable axially of the shaft, means' operable by the axial movement of said member for actuating predetermined ones of said contact blades` to effect another circuit conditioning function, and

' means for preventing the completion of said lastydetermined ones of said contact blades to effect at least one circuit conditioning function, a manual control member for rotating said shaft and movable axially of the shaft, a pivoted member arranged cooperatively with predetermined ones of said contact blades and adapted to actuate the said blades to effect another circuit conditioning function, and means including a cam on said control member for actuating said pivoted'member in response to axial movement of the control member.

18. In an electrical switch, a plurality of stationary contact elements, means for supporting said elements, a plurality of resilient contact blades, means for supporting said blades in cooperative relation with said elements, a rotatable shaft arranged cooperatively with said blades, a plurality of cams on said shaft for actuating predetermined ones of said contact blades to eiect at least one circuit conditioning function, a manual control member for rotating said shaft and movable axially of the shaft, a pivoted member arranged cooperatively with predetermined ones of said contact blades 4and adapted to actuate the said blades to eect another circuit conditioning function, means including a second pivoted member operable by axial movement of said cogitrol member to actuate said first pivoted member, and means operable by said second pivoted member to prevent completion of said last-mentioned circuit conditioning function until said control member is restored to its normal axial position.

STEPHEN J. ROESCH.

JOSEPH W. MYERS.

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