US2180233A

US2180233A - Timed cooker

Info

Publication number: US2180233A
Application number: US4899A
Authority: US
Inventors: Maurice H Graham
Original assignee: McGraw Electric Co
Current assignee: McGraw Electric Co
Priority date: 1935-02-04
Filing date: 1935-02-04
Publication date: 1939-11-14
Anticipated expiration: 1956-11-14

Description

NOV. 14, 1939. H, GRAHAM 2,180,233

TIMED COOKER Filed Feb. 4, 1935 ll Sheets-Sheet 1 .F 77 INVENTOR MAURICE H. GRAHAM ATTORNEYS NOV. 14, 1939. H, GRAHAM 2,180,233

TIMED COOKER INVENTOR MAURICE H. GRAHAM By M ATT Rrvcys NOV. 14, 1939. M, GRAHAM 2,180,233

TIMED COOKER Filed Feb. 4, 1935 ll Sheets-Sheet 3 INVENTOR I y-29, MAumcz H. GRAHAM v mp/147W ATT always I Nov. 14, 1939. M. H. GRAHAM TIMED COOKER Filed Feb. 4, 1935 ll Sheets-Sheet 5 m T N E v m v MAURICE HfiRAHAM ATTORNEYS Nov. 14, 1939. M. H. GRAHAM 2 TIMED COOKER Filed Feb. 4', 1955 11 Sheets-Sheet 7 INVENTOR MAURICE H.6RAHAM W M W ATTORNEYS- Nov. 14, 1939. M, 'H GR H M 2,180,233

TIMED COOKER liiled Feb. 4, 1935 ll Sheets-Sheet 8 INVENTOF? MAURICE H.6RAHAM ATTORNEY-5 Nov. 14, 1939.

Filed Feb. 4, 1935 11 Sheets-Sheet 9 /3$ Fzyi'i I MM M/ H 2 /36 26% I Ad? J} v w fj 194 /6 26 M1, 466 La I m my 5&9 '4/9 j Mo F) as INVENTOR MAURICE H.6RAHAM Arromvsys NOV. 14, 1939. GRAHAM 2,180,233

TIMED COOKER Filed Feb. 4, 1935 ll Sheets-Sheet 10 g m m2 452 a M? m 2 5 a? 2; iii E: 2;: ii Hi ii: 4 /73 iii H a ii i =i M ii iii 0 I; H H H1 :l H 1:: H:

2 6 L57 /-6 45c i /jpln Fig-25 INvENToR MAUHICEI'LGRAHAM ATTOFTNEY5 Nov. 14, 1939. M. H. GRAHAM 2,180,233

TIMED COOKER Filed Feb. 4, 1935 ll Sheefis-Sheet ll L My /66 ,46/54' k 1/ 145 F 2 7 INVENTOR MAURICE H.6RAHAM I47 md g yfl mo,

Patented Nov. 14, 1939 UNITED STATES PATENT OFFICE TIRED COOKER Application February 4, 1935, Serial No. 4,899

36 Claims. (Cl. 219-19) My invention relates to time-controlled cookers and more particularly to automatic electric toasters, walile irons and like cooking apparatus, wherein the material to be toasted or cooked is combined with a container or holder therefor associated with primary electrical heating elements. Toasters, waflle irons and like electrical cooking apparatus require timing mechanism that will operate accurately under varying conditions of use and that will maintain accuracy of toasting or cooking control, irrespective of the varying temperatures of the apparatus, cooking oven or space, and which variations in temperature will occur at the initiation of the toasting or cooking actions, depending on the rapidity with which the successive actions are produced. These actions which I have demonstrated by long continued tests involving thousands of continuously repeated operations, I have accomplished in my present invention.

To the above ends, generally stated, the invention consists of the novel devices, combinations of devices and arrangement of parts hereinafter described and defined in the claims.

Considering the matter particularly in respect to electric bread toasters, it is a well known fact that the time required to toast a slice of bread to a predetermined or desired degree, varies with the variations in the temperature condition of the toaster at the commencement of the particular toasting operation. The same statement is true to a greater or less degree in the cooking or baking of various other food articles or the like. In the case of an electrically operated toaster, it will take a relatively greater amount of time to toast a first slice of bread to a predetermined degree upon insertion into a cold toaster, than will be required to toast a subsequent bread slice inserted into the toaster after it has been operated a few times and been heated up.

For some years there has been marketed electrically operated toasters and other cookers provided with timing devices set to operate upon the completion of the cooking operation to automatically terminate the cooking operation. Such cookers, were, however, not capable of producing uniform results because of necessity for variable timing, due to the change in their temperature condition, upon the occurrence of successive operations. In order to remedy this defect, it has been proposed to provide means for varying the operation of the timing device, in accordance with the variations in temperature of the cooker, and thereby to compensate for the increase in cooking temperature occasioned by frequent use. One of such means is a temperature responsive device subject to some heat condition of the cooker, such, for example, as a thermostat in the toaster disclosed in the Forbes Patent No. 1,665,735, of date April 10, 1928, which controls the operation oi the timing mechanism for the toasting of the bread slice. Again, in the case where a thermostatic heating means is employed, for the automatic timing of the toasting or cooking interval, it has been proposed to provide means for preheating the timer means prior to use for controlling the cooking operation after the cooker has been initially operated and heated, as a means for compensating for the increased temperature of the cooker.

The simple type of thermostatic timer such as now generally used in oil burner control circuits commercially known as warp strips or bimetallic strips, which consists of the thermally responsive elements, and the deforming of which is determined by the interval necessary to heat the same to a predetermined temperature, is not commercially applicable for use to control any device such as a toaster, waflle iron or the like, adapted to be operated in rapid succession. The obvious reason is that when the warp'strip has been heated, the device cannot again serve as an efficient timer until the strip has again cooled down. In an effort to overcome this difficulty and enable the use of a thermostatic timing means, in a device such as a toaster or the like, adapted to be operated in rapid succession, it has been proposed to employ a plurality of thermostatic timers in an arrangement in which it is intended that one of the thermostatic elements will be allowed to cool off while the remaining timer is in operation; but this latter structure, so far as I am aware, has not been successfully operated.

My present invention provides a timer which is self-compensating for increases or other variations in cooking temperature occasioned by use, and which is therefore particularly adapted for use in automatic regulation of an electrically operated toaster or cooker, without the necessity of any other means for varying the operation of the same to compensate for changes in the cooking temperature.

It is a special object of my invention to provide a timer adapted to be set in operation upon the completion of the cooking interval of an electrically operated toaster or cooker and arranged to automatically terminate said intervals, and which timer inherently and in its normal operation, varies the cooking interval in accordance with or proportionate to the changes in the heat condition of the cooker, resulting from frequent repeated use, whereby the necessity of providing any additional or secondary means for changing the normal operation of. the timer to compensate for cooking temperature changes, is entirely obviated.

Stated in another way, a broad purpose of the invention is the provision of a. single thermostatic timer in which a heat-responsive controlling element in itself can be operated over and over again in rapid succession and which, when thus used, will automatically compensate for the variations in the cooking or heat-applying temperature due to various intervals or conditions between the repeated uses.

Again, it is a general object of the invention to provide a single thermostatic timer in an automatic electrically operated cooker or other device that can be operated in rapid succession and which is of such nature that in its normal operation, it inherently compensates for temperature changes of the cooker or device.

More particularly, the invention contemplates the utilization of the time consumed in allowing the thermally responsive device to cool, as well as the time required to heat it, in order to establish a cooking interval, and it is a further object of the invention to provide a thermostatic timer in which a cooking or heat applying interval is determined from the time required to heat a thermally responsive device to a predetermined temperature, and to permit it to cool to a second predetermined temperature.

As will hereinafter appear, in the operation of my improved timer as applied, for example, to an electrically operated commercial toaster or cooking device, each cooking interval involves two sub-intervals, to wit: (a) a variable subinterval required to heat the device from an uncertain or variable cool or low temperature condition to a predetermined higher temperature; and (b) the invariable or constant sub-interval required to permit the timer to cool from the predetermined high temperature down to a predetermined cooled or relatively low temperature. By a suitable and simple adjusting device, the entire cooking interval made up of the above noted sub-intervals (a) and (b), can be varied, to thereby increase or decrease the degree or extent of the complete toasting or cooking interval; but with the timer set, the said intervals (a) and (b) will be as above stated, to wit: the sub-interval (a) variable, and thesub-interval (b) constant.

The above and numerous other objects of the invention will become more apparent upon consideration of the devices illustrated in the accompanying drawings.

Figs. 1 to 14, inclusive, illustrate my invention as embodied in a commercial bread toaster;

Figs. 15 to 20, inclusive, illustrate my invention as incorporated in a bread toaster of somewhat modified form;

Figs. 21 and 22 illustrate a still further modified form of the invention embodied in a toaster;

Figs. 23 to 28, inclusive, illustrate the invention as incorporated in a wafiie iron; and

Fig. 29 is a diagrammatic view illustrating a still further modified form of the invention.

Referring to the above drawings, wherein like characters indicate like parts throughout the several views;

Fig. 1 is a vertical front to rear section taken on the line ll of Fig. 3;

Fig. 2 is a vertical front to rear section taken on the lines 2-2 of Figs. 3 and Fig. 3 is a bottom plan view of the toaster shown in Fig. 1;

Fig. 4 is a vertical section taken on the line 4-4 of Fig. 6;

Fig. 5 is a transverse vertical section taken on the line 5--5 of Fig. 1;

Fig. 6 is a front elevation of the toaster shown in Fig. 1, some parts bein sectioned on the same line as in Fig. 5 but illustrating difierent positions of the parts;

Fig. 7 is a transverse vertical section taken on the line of Fig. 2;

Fig. 8 is a fragmentary section taken on the line 8--8 o Fig. 5;

Fig. 9 is a side elevation showing in detail the thermostatic element herein designated as a timer;

Fig. 10 is an edge or side elevation of the timer shown in Fig. 9;

Fig. 11 is a section taken on the line H--II of Fig. 9; and

Figs. 12, 13 and 14 are diagrammatic views illustrating the wiring of the electrically actuated or influenced elements of the toaster, and illustrating different positions of the removable parts under different conditions.

Figs. 15 and 16 illustrate a toaster very much like that described in connection with Figs. 1 to 14, inclusive, but involving a somewhat modified arrangement of the immediate circuit-actuating connections.

Fig. 15 is a view corresponding to Fig. 5 but illustrating the modified circuit-actuating connections; and

Fig. 16 is a diagrammatic view illustrating the circuits of the modified arrangement of the toaster illustrated in Fig. 15.

Fig. 17 shows a somewhat modified form of the toaster being a vertical front to rear section taken on the line I'I-I'I of Fig. 19;

Fig. 18 is a section with some parts broken away taken on the line I8l8 of Fig.

Fig. 19 is a transverse vertical section taken on the line Iii-l9 of Fig. 17;

Fig. 20 is a view corresponding to Fig. 19 but with some parts shown in full and with certain of the parts moved to a different position;

Fig. 21 is a fragmentary section taken on the line 2l2l of Fig. 19, some parts being removed; and

Fig. 22 is a diagrammatic view with some parts in perspective, illustrating the wiring of the electrically influenced parts of the toaster shown in Figs. 17-22, inclusive.

Figs. 23 to 28, inclusive, illustrate the invention as involved in the construction of a waffle iron;

Fig. 23 is a vertical section taken from front to rear centrally through the waflle iron;

Fig. 24 is a horizontal section taken on the line 2424 of Fig. 23;

Fig. 25 is a section taken on the line 2525 of Fig. 24, some parts being broken away;

Fig. 26 is a bottom plan view of the lower waiiie grid looking upward from the line marked 26-26 on Fig. 23;

Fig. 27 is a fragmentary section taken on the irregular line 21-21 of Fig. 24, some parts being broken away;

Fig. 28 is a diagrammatic view illustrating the circuits and circuit-actuating connections of the walileironshowninFlg.23;and

Diagram views, 12, 1s and 14 Before describing in full the various drawings which illustrate several diilerent embodiments of the invention, attention will first be directed to Figs. 12, 13 and 14. These-views diagrammatically illustrate an embodiment of my invention which has been primarily daigned for incorporation in an automatic electrically operated bread toaster, but which either in the identical form or slight modification, will serve as an automatic timer for numerous other devices. It. is thought that by first considering the action of the system Or scheme involved in these views, the later described application thereof in a toaster or the like will be more readily understood. The scheme illustrated in these views includes, (in addition to the circuit connections) heating coils or other heat radiators, a master switch, a master switch actuator, a shunting switch, an electro-magnetic tripping device for tripping the master switch actuator, and a thermally responsive timer, which latter includes an expansible and contractable thermally responsive element and a timer switch.

Referring more in detail to these diagram views, 3| indicates heat-radiating elements or coils such, for example, as would be used in a toaster. 32 indicates a normally open master switch. 33 indicates a master switch actuator. 34 indicates a shunting switch that is under strain to open. 35 indicates a tripper coil or solenoid, which, when energized, lifts a core or plunger 35 that is under normal strain to drop when relieved from the action of said solenoid or coil 35. This plunger 35 carries 9. lug or projection 31 which, when the plunger is dropped, closes the shunting switch 34. The master switch actuator 33 is shown as provided with a latch lug or projection 33 which is arranged to be engaged by a latch dog 33 that is intermediately pivoted at 40. Plunger 38 carries also a pivoted dog-releasing lug or element 4|.

The timer includes as its main element, an expansible and contractable timer bar 42, preferably made of metal such as aluminum (which has a high co-efiicient of expansion), and which is in close heat exchange association with a heating coil 43. One end of this timer bar 42 is pivotally anchored at 44 and the free end ther of is pivotally connected to the intermediate portion of a timer switch lever 45 that is pivoted at 46 and at its free end works between

switch contacts

41 and 48. Lever 45 is made oi metal and is an electrical conductor. Contact 41 is shown as threaded through a fixed bearing 43, and is a fixed contact except for adjustments required to vary the entire toasting or heat-applying interval designated above as made up of sub-intervals (a) and (1)). Contact 48 is a yielding contact and, as shown, is in the form of a metal stem that works through a fixed bearing and is springpressed toward the contact 41, the extreme movement in that direction being limited by a head on the rear end of said stem. In the particular application illustrated, contact 43 works freely through a threaded bearing sleeve 53 which, in turn, is adjustable in a fixed bearing For the purpose of the present illustration, contact 41 will be treated as a fixed contact, and contact 43 as a yielding contact.

The main leads or supply wires are indicated by the

numerals

52 and 53. Lead 52 is connected to one side of master switch 32, the other side of which switch is shown as connected to one of the heating coils 3| by a wire 54. The first noted heating coil 3| is connected to the second heating coil by a wire 55, and the latter is connected by a wire 55 to one side of the shunting switch 34. The other lead 53 is shown as directly connected to that side of the shunting switch that is opposite to the connection just noted made by wire 56 to the other side of said switch, and this same side of switch 34 is connected to one end of solenoid coil 35 and to one end of the timer heating coil 43 by a wire 57. The other end of said coil 43 is connected by a wire 58 to the wire 56. The other end of solenoid coil 35 is electrically connected to the switch lever 45 by a wire 59 and to a bearing 5| and hence to the yielding contact 48 by a wire 50. In the wire or conductor 60 is interposed a high resistance coil 8| which, in this particular instance, may be assumed to have a resistance of 1400 ohms. The said bearing 5| and hence the movable contact 48 is electrically connected by a wire 62 to the same side of the master switch 32 to which wire 54 is connected. Wire 38 connects bearing 49 and hence contact 41 to that side of the switch 34 to which the

wires

53 and 51 are connected.

At this time and until further detail description may be given, the reader is asked to assume that the master switch actuator 33 is under strain to move upward, that it has a connection, which when it moves upward, will open the master switch 32; and that when said actuator 33 is forced downward to the position indicated by full lines in the said views, Figs. 12, 13 and 14, it will close said master switch.

Operation With these facts in mind, the operation of the scheme shown in the said Figs. 12, 13 and 14 will be as follows: Normally switch actuator 33 will be in the raised position indicated by broken lines in Fig. 12, and the tripping plunger or member 36 will be in its lowered position indicated by broken lines in said Fig. 12. When the said

elements

33 and 35 are in their broken line positions Fig. 12, master switch 32 will be in open position and there will be no flow of current through any of the conductors or elements of the device. When it is desired to render the system operative, the operator will depress the switch actuator 33, thereby permitting or causing said master switch 32 to be closed, so that current will then fiow not only through the heating coils 3|, but also through the tripping solenoid 35 energizing the same and causing opening of shunting switch 34, permitting current to iiow through timer heating coil 43, thereby causing both coils 3| and 43 to generate heat.

In the drawings, the flow of current under the several conditions is intended to be indicated by the heavy wire-indicating lines. Thus, as indicated in Fig. 12, the flow will be from lead 52 through closed master switch 32, wire 62, contact 48, lever 45, wire 59, coil 35, and wire 51 to lead 53, and at the same time there will be a flow of current through

wires

54 and 55, heating coils 3|, wire 58, timer coil 43 and wire 51 to lead 53. This is the condition illustrated in Fig. 12, at which time lever 45 is engaged with yielding contact 43 and at which time, because of the path of least resistance, the current will flow through tripping coil 35, through said lever and wire 59, rather than through the high resistance coil 6|.

When the master switch actuator was manually depressed as above described, its lug 36 passed below the engaging end of latch dog 33 in position to be latched down by said dog, but at the same instant and while said actuator was held depressed, master switch 32 was closed (as described), causing energization of tripping coil 35 and the latter being energized instantly raised the plunger 36 to its uppermost position shown by full lines in Fig. 12'. As the said plunger was raised, its pivoted lug 4| engaged the adjacent end of latch dog 33, moving the same into position to release said actuator 33, but the action was so quick that said dog resumed its latching position before there was any upward movement of said actuator 33. when plunger 36 is moved upward as just described, shunting switch 34 was opened, but the importance of this action will be discussed later on.

When the condition of the system is that shown in Fig. 12, current will flow through the coils 3| and 43 and 35, as just stated, until under the action of heat from coil 43, timer bar or element 42 has been expanded so as to disengage lever 46 from contact 48, as shown in Fig. 13. The only immediate effect of this action is to break the circuit leading to the tripping coil 35 through the low resistance circuit (including the lever 45) and to cause the current to then flow through high resistance coil SI and from thence through said tripping coil. The current then flowing through solenoid coil 35 will be suiiicient to hold plunger 36 raised, but not sufficient to cause it to be raised from its lower to its uppermost position. Under the conditions illustrated in Fig. 13, current will still flow through the heating elements 3| and through the timer coil 43, so that the bar 42 win continue to expand until the free end of lever 45 has been engaged with fixed contact 41, as shown in Fig. 14.

Under the conditions existing in Fig. 14, tripper coil 35 will be shunted out by the circuit through lever 45, and through wires 59, 5'1 and 88, thereby permitting plunger 36 to drop to its lower position, in which position its lug or projection 31 closes the shunting switch 34. Under dropping movement of the plunger, pivoted latch dog releasing lug 4| freely passes the adjacent end of latch dog 39 without any action thereon, since the downward movement of the adjacent end of said dog is limited by a suitable stop 39'.

When shunting switch 34 is closed, as shown in Fig. 14, by dropping of the plunger 36, the circuit will be closed between the opposite sides of said switch, thereby shunting out the circuit -through the timer heating coil 43, but leaving the circuit through the heating coils 3| still closed for the full flow of current therethrough. When the circuit through the timer heating coil 43 is thus shunted out, the timer bar or element 42 will immediately commence to cool off and to contract, starting the movement of the free end of the lever 45 from engagement with fixed contact 41 toward engagement with a movable contact 48. While lever 45 is thus being moved toward engagement with contact 48, current will continue to flow through the heating elements 3|, but not, of course, through the timer heating coil 43; plunger 36 will remain in its lowered position holding shunting switch 34 closed, and master switch 32 will be held closed by the actuator 33, 'which is still latched down by dog 33. When,

however, lever 45, by continued contraction of bar 42, is again engaged with contact 46, the circuit through tripper coil 35 will be then again closed through lever 45, as shown in Fig. 12, thus causing said coil 35 to be energized with sufficient force to pull plunger 36 from its lowered position shown in Fig. 14, back to its raised position shown in Fig. 12.

The upward movement of said plunger 36 thus produced, accomplishes two results, to wit: it opens or permits the shunting switch 34 to open, and by engagement of pivoted lug 4| (which has a limited outward swinging movement) with the adjacent and of latch dog 39, releases the master switch actuator 33, thereby permitting the latter to move upward and in its upward movement open the master switch, thereby cutting oiI all supply of current to the system or device. When this happens, tripper plunger 36 drops back to position shown by broken lines in Fig. 12, ready to repeat its above described function in the next cycle of operation.

From the foregoing, it is evident that the time of the complete toasting or cooking action is the time required for the lever 45 to move out of engagement with contact 43 and into engagement with contact 41 (which is the variable sub-interval (a) above referred to), plus the time required for the said lever to move from engagement with contact 41 back into engagement with contact 48 (which is the constant or unvarying sub-interval above referred to as sub-interval (b). The

extent to which movable contact 48 will be depressed or moved against its spring tension under the action of lever 45, will vary with the extent to which the thermally responsive bar or element 42 is permitted to cool.

With the so-cailed fixed contact 41 set in a deflnite position, the heating elements will be operated so as to produce always substantially the same cooking or heating actions, regardless of the temperature of the apparatus or its parts (including, of course, the element 42), at the instant that the apparatus is set in action to toast bread or produce other cooking or heating action.

As illustrated in the drawings, the stem of contact 41 has threaded engagement with its bearing 43 and hence is capable of being set in different adjustments, and of course, the setting thereof into different adjustments will vary the total time interval and the intensity of the repeated toasting, cooking or heating actions, which actions, however, will be constant in respect to the result, for any particular setting of the relatively fixed contact.

In Figs. 1 to 11, inclusive, I have illustrated a commercial toaster in which the scheme and structure diagrammatically illustrated in Figs. 12, 13 and 14 is applied.

Referring now particularly to these views, it may be stated that in this embodiment of the invention, the toaster has very much the appearance of that of the well-known "Toastmaster toaster, but differs therefrom very materially in its vital structural features and the operation thereof. As here illustrated, the base portion of the toaster is made up of a raised base plate 63 and a bottom base plate 64 supported by foot I blocks 65. Rigidly secured on and risingfrom the base plate 63 is a frame made up of upright front and rear plates 66 and 61, that support laterally spaced insulating sheets 66, preferably mica, on which latter the heating coils 3| are applied. Detachably mounted on the base plate 63 and surrounding and enclosing the mica sheets 66 and various other parts, is a casing 63, preferably of light sheet metal and on the top of which a crown sheet or top plate III is applied. This crown sheet II is provided with a centrally located bread discharge passage ll through which, as will presently appear, the bread slices may be passed into and out of the oven or toas l;- ing chamber formed between the coils 3|.

Detachably mounted on top of the end plate 66 is a rectangular marginal rim 12, the opening in which is larger than the bread passage H so that it does not interfere with the passage of the bread through the latter into and out of the toasting chamber. Guide rods 13 are secured to and depend from the rim l2 and will serve to hold the bread out of contact with the heating coils 3|. In Fig. 4, a slice of bread is indicated by the character 1 By reference particularly to Figs. 2, 4, 5 and 6, it will now be noted that the vertically movable element 33, heretofore described as a master switch actuator, is provided with grooved rollers 14 that run on a vertical guide post 15 rigidly secured at its lower end to the base plate 63 and at its upper end to a projection 12' of the rim 12. This plate or member 33 affords a vertically movable carriage and to facilitate the manipulation thereof, it is shown as provided with a projecting handle 13 that works through a vertical clearance slot in the front of the casing 59. This master switch actuator 33 is provided with a projecting arm 11 to which is rigidly secured a skeletonized breadsupporting table or support 13 that is movable vertically between the heating coils or elements 3|. Table 13 has lateral projections through which the lower ends of the guide rods 13 are freely passed. Arm 11 works through a vertical slot in the frame plate 55 and holds carriage plate 33 against rotation on post 15.

The carriage made up of the plate 33 associated parts is put under tension to move to its uppermost position shown by dotted lines in Fig. 4, by a coiled spring 13, one end of which is adjustably anchored to a notched flange 30, formed in the base plate 63 and the other end of which is connected to the lower end of a vertically disposed arm 8! that is rigidly secured to a long lever 82. This lever 82 is pivoted at 33 to a lug on the rear frame plate 61 and at its free end it is provided with a laterally projecting stud 84, the inner end of which in the structure illustrated, is embraced by a pronged end of a bracket 35, see Figs. 2, 5 and 6, which, in turn, is rigidly secured to the carriage-forming actuator plate 33. The upwardly projected end of the arm 8| is pivoted to a switch-actuating link 85, the front end of which is connected to the upper end of the movable element of the master switch 32 by a yielding connection made up of a short coiled tension spring 81 that connects studs on the switch member and on said link.

By reference to Figs. 9, l and 11, it will be noted that the timer bar 42, as preferably designed, is made up of a sheet of expansible metal, to wit: preferably aluminum, bent into fiat U-shaped cross-sectional formation to enclose take up slack, but does not, however, control the movements of said lever, the latter being under the complete control of timer bar 42, as already described.

The pivot 40 of the latch dog 39 described in connection with the diagram views, Figs. 12, 13 and I4, in the present instance, is shown as a rod supported by lugs 89 of a pair of upright parallel bars 30 that are rigidly secured to one of the front corner portions of the base plate 33 (see Fig. 5). The stop pin 33' is also applied to these lugs 33, see Figs. 5, 6 and 8. Also, in this application of the invention, the tripping plunger 33 is provided with a flat depending portion 33' which works through a slot in the base plate 63 and through a slot in a stop bar 9| that is rigidly secured to the upright bars 90. Thus plunger 36 which carries the tripping and switchclosing elements is held against rotation on its axis. Lock dog 33 can be gravity held in its looking position shown in Figs. 5, 6, 12 and 14, but for this purpose, it is shown as additionally held by a light torsion spring 32, best shown in Figs. 5, 6, and 8. As best shown in Fig '7, louvered plates 93 are applied between the coil-supporting plates and the outer sides of the casing 69.

The tripping coil 35 is shown as supported on a shelf 34 secured to the bars 30, see Figs. 5 and 6, by reference to which bars it will also be noted that the normally separated contacts or members of the tripping switch 34 are secured and insulated from each other by an insulating block 95 secured to the lower portions of the bars 30. A manner of applying the invention broadly illustrated in the diagram views, Figs. 12, 13 14, to the :1 toaster illustrated in Figs. 1 to 11, inclusive, as now been described, and the gene al operation has already been made ciear by the discription of the said diagram views. A short summary of the action of the commercial toaster with the invention thus applied, is as follows:

Summary of operation of inve tion applied as in Figs. 1 to 14, inclusive Normally, or when the device has been out of use, the parts will be in positions shown by full lines in Figs. 1, 2 and 5, and by broken lines in Fig. 4, and the current will be entirely out off the toaster because master switch 32 will then be open. The bread slice is then inserted through the passage H and. placed on the table 18. Then by taking hold of the handle 16, the carriage is depressed, thereby lowering the table 18, bringing the bread into toasting position between the heating elements or coils 3|; and this same movement of the plate or carriage 33, operating through the lever 82 and arm 8|, against tension of spring 19, closes the master switch, thereby turning the current onto the heating coils or elements 3| and timer coil 43. The toasting action will then be initiated and will'continue as described in connection with diagram views, Figs. 12, 13 and 14, until the complete toasting action has been accomplished; whereupon, the tripper coil 35 will be energized, raising the plunger 36, causing latch dog 39 to release the carriage 33. When carriage 33 is thus released, spring 13 will quickly move carriage 33 upward, causing the table 18 to project the bread partially from the toaster and the master switch to be opened, restoring the toaster to normal or inoperative condition. The exact cycle of operation of the toaster and the important results thereof have been fully described in connection with the diagram views and need not be here repeated.

From the foregoing it will be observed that in the particular arrangement described, the auto matic means for tripping the master switch actuator, causing opening of the master switch and movement of the bread from the toasting zone or oven, in addition to the several important functions performed, serves as a means for indicatlng the completion of the timed toasting, cooking or heating interval. From this it further follows that the so-called means for indicating the completion of the timed interval can- Figs. 15 and 16 The structure illustrated in Figs. 15 and 16, except for some of the circuit connections and the construction of the shunting switch, is like that fully described in connection with Figs. 1

to 14, inclusive, and hence those parts that are identical with the structure of the said Figs. 1 to 14, are here indicated by the same characters with exponent 11 added thereto. The shunting switch of this structure which is employed instead of the heretofore described switch 34, involves three

contact members

34, 34" and 34", which members are anchored to 'an insulating block 980 mounted on a fixed part of the framework of the toaster, such as the bars 000:. Contact 04" is under tension normally to maintain electrical engagement with contact 34' but out of engagement with contact 30", and its upper end is bent so that it will be forced out of engagement with contact 34' and into engagement with contact 04" by lug 31a when plunger 36a is raised.

By reference to Fig. 16, it will be noted that in this arrangement, bearing 49a and hence fixed contact "a is electrically connected to contact 34 by a wire 01; that the timer healing coil 43a is connected to said contact 34" by a wire 98; that one terminal of tripper coil 35a is connected to contact 34 by a wire 89; and that one terminal of one of the heating element coils 3Ia is connected to contact 34' by a wire I00; that the main lead 52a is connected to one side of master switch 32a by a wire I M; and that the main lead 53a is connected to contact 34" by a wire I02.

Diagram view, Fig. 16, indicates the normal condition ofthe toaster illustrated in Figs. 15 and 16, and the operation thereof will be exactly that described in connection with Figs. 1 to 14, inclusive, except that at the time when lever 45a engages fixed contact 41a at the completion of the above described sub-interval (a), the circuit leading to timer coil 43a will be absolutely opened, whereas, in the previously described arrangement, said circuit leading to said timer coil is simply shunted out of action. More specifically described, the said action will be as follows:

when master switch 02a is closed by depression of actuator 33a, the current will first flow through trip coil 35a, causing plunger 36a to be raised and its lug 31a to move contact 34" out of engagement with contact 34' and 50 engagement with contact 04'", thereby closing the circuit through the heating coils 0Ia and timer heating coil 43a. Then when, under expansion of member 42a, lever 45a is engaged with contact "a, current willtake the path of least resistance from master switch through wire 02a, wire 60a, resistance "a, wire "a, lever a, contact "a and wires 01 and I02, thereby shunting out the tripping coil 05a and permitting plunger 38a to drop back to its position shown in Fig. 16. When this takes place, shunting switch contact 34" will again engage with contact 34, thereby absolutely opening the circuit through timer heating coil 43, permitting the element a to commence to cool; but at this time, the current will still flow through the heating coils 3Ia. by way of wire I00, contacts 34' and 34", and wire I02.

From the description just given of Figs. 15 and 16, it will be understood that the timer coil can be cut on of action either by shunting it out or by opening or breaking its circuit. The term timer cut out is, therefore, herein used in a sense broad enough to cover either or both of the said actions or manners of rendering inoperative the coil or device which supplies heat to the thermally responsive timer.

Attention should have been called to the fact that contact 34" makes contact with 30" before it breaks contact with contact 34'.

Figs. 17 to 22, inclusive The structure illustrated in these views in many respects is like that illustrated in Figs. 1 to 14, inclusive, but differs therefrom in the circuit connection and in some of the details of mechanism. Those parts of the structure illustrated in these last noted views, that are identical with those illustrated-in Figs. 1 to 14, inclusive, are indicated by the same numerals with the exponent b added thereto.

In this modified structure, the master switch 32b is connected to the vertically movable carriage "b by the same connections, and is subject to the same spring that is fully described in connection with Figs. 1 to14. In this arrangement, however, the so-called. shunting switch and the tripping switch are of modified form. The shunting switch shown comprises a circuitclosing lever I00 and co-operating contacts I 04. Lever I03 is pivoted to front plate 66b at I05 and contacts I04 are also supported from said plate 66b but insulated therefrom and from each other. The carriage 33b carries an extension I06 which has a finger I01 that underlies the intermediate portion of said lever and holds the same raised, as shown in Fig. 22, when the carriage is in its normal raised position. Lever I03 has a laterally yielding spring extension"! that normally rests on the extremeupper end of a long lever I 09, and which is pivoted near its lower end at IIO to a bracket III that is rigidly secured on the base plate 00b. Lever I00 is shown as made up of two sections that are rigidly connected but insulated the one from the other at III.

At its extreme upper end, lever I00 is formed with a notch III into which the end of lever extension I00 will drop under certain conditions.

A light coiled spring Ill attached to the end of lever extension I08 and to the intermediate portion of lever I09 yieldingly pulls I03I00 downward and holds the latter normally on the fiat upper end of said lever I00. In a rearward direction, movement of the free end of the flexible arm extension I00 is limited by a relatively fixed stop I II which, as shown, is carried at the upper end 01' a stop lever I I8 that is intermediately pivoted to a suitable bearing on a fixed part, such as the front plate 68b. The lower end of this lever is shown as swivelled to an adjusting screw II! that works through a nut block II8 on the base 33b and is provided at its front end with an operating knob I I8. The free end of the thermally influenced timer bar 42b is shown as connected by a short thrust link I to the extreme lower end of the lever I03.

The tripping switch is shown as made up of two metallic spring strips I2I, the upper ends of which are rigidly connected but insulated from each other by a block I22. One of the members I2I is anchored to a block or element I23 rigidly secured to the front plate 66b. One side of the master switch 32b is connected to main lead 52b and the other side of said switch is connected by a wire I24 to one terminal of the timer coil 42b, the other terminal of said coil being connected by a wire I25 to one of the switch contacts I04, this same contact being connected by a wire I26 to one of the heating coils 3Ib. One of the said coils 3Ib is connected by a wire I21 to the relatively fixed member of the tripper switch contacts I2I. The other or movable switch contact I2I is connected by a wire I28 to one terminal of a tripper magnet coil I23, the other terminal of which is connected by a wire I30 to the switch contact I04 to which the wire I25 is not connected.

Tripper magnet I23 has a movable armature I3 I, the free end of which is under yielding strain to engage a latch detent or lug I32 that is carried by a lower front portion of the carriage 33b. Lever I03 at its intermediate portion, see particularly Fig. 22, is provided with a lateral pin or projection I33 that is engageable with the depending end of the movable contact I2I.

Operation of structure of Figs. 17 to 22, inclusive The normal position of the various parts is illustrated in Figs. 17, 19 and 22, under which conditions the carriage 33b and bread carrier 181) are raised and master switch 32b is open. When a slice of bread has been inserted on the bread carrier 18?), the carriage 33b may be depressed by engaging and depressing the handle 1617. This downward movement of the carriage (which as before noted, serves also as a master switch actuator) closes the master switch and causes the carriage to be latched in its lower switch-closing position with the bread in position for toasting, by engagement of the armature I3I with the latch lug I32. When this takes place. the current will flow from lead 52b through master switch 32b, wire I24, timer coil 43b, wire I25, and heating coils 3Ib to lead 53b. When timer bar 42b is subject to the heat from timer heating coil 431), it will commence to expand and will move the upper end of lever I03 rearward or toward the right in respect to Fig. 22, and will carry the pin I33 away from the free end of the movable contact I2I, thereby causing the tripper switch to open. However, even before this tripper switch is opened, no current can flow through the tripper magnet I23.

Under expansion of timer bar 4217, the yielding lever extension I08 will be forced against the relatively fixed stop II5, but when said timer bar is expanded to a certain predetermined extent,-

its extreme upper end will be carried beyond the end of lever extension I08, and thereupon, spring II4 will cause switch lever I03 with its extension III to drop, thereby closing the circuit between the shunt switch contacts I04.

At this time, it will be understood that the carrier extension I03 and its lifting finger or lug I01 will be in the lowered position due to the lowering of the canine 331). When the circuit is thus closed between contacts I04, the flow of the current will be from lead 52!) through switch 321), arm I03, contacts I04, and heating coils 3Ilto lead 53b; but the circuit through timer coil 43 will then be shunted out so that timer bar 421) will be permitted to cool and will contract. When said bar 42b is contracted far enough to permit the points of tripper switch contacts I2I to engage, the circuit will then be closed through tripping coil I23 by way of wires I30, I28, switch contacts I2I and wire I26.

When tripper coil I23 is energized, its armature III will be attracted, thereby disengaging the latch lug I32 and permitting the carriage 33b to be immediately raised under the action of its spring 19b. When the carriage is thus moved back to its raised or normal position, master switch 3211 will be opened, cutting ofi the entire supply of current and lever I03 will be again raised out of engagement with contacts I04 and the spring arm I08 will, under its own spring tension, snap back to the position shown in Fig. 22 over the upper end of lever I03.

With the stop I I5 set in a definite position, the toasting actions will be uniform, that is, will be toasted to a certain degree. The degree to which the bread will be toasted may be increased or decreased, however, by adjustments of the lever H6 and its stop II5.

Wame iron, Figs. 23 to 28, inclusive These figures illustrate the invention incorporated in a waflle iron, which comprises a suitable base I34 which supports an upstanding casing I35. The numeral I36 and I3! indicate, respectively, the fixed and movable grids of the waiiie iron, the former of which is supported on the upper edge or rim of the casing I and the latter of which is contained in a cap-like cover plate I38 which, in turn, is hinged to 2. lug I39 on the casing I35. The heating coils are applied to the respective grids in proper heat exchange relation in respect thereto. Preferably, and as best i1- lustrated in diagram view, Fig. 28, each grid is provided with two heating coils 3Ic and 3Id that are connected in multiple by a. circuit presently to be described.

The thermally influenced timer bar 420 which is similar to the earlier described timer bar 42, is provided with a heating coil 430. This bar 42c is shown as located just above the base I34 and is anchored thereto at 44c. The main or master switch of this arrangement is shown as in the form of a metallic lever I40 and a fixed contact I H Lever I40 is shown as pivoted to the base I34 at I42 and is subject to a spring I43. Lever I 40 has a yielding contact I44 that is directly engageable with contact I and with a spaced contact I45. Contacts HI and I45 may take various forms, but as shown, they are in the form of screws that are adjustable through lugs on the base plate I34.

The shunting switch of this structure, as shown, comprises a lever I46 and a fixed contact I41. Lever I46 is intermediately pivoted at I48 to a carrier plate I49 that is slidably mounted on the base plate I34 under the action of an adjusting screw I50 that is swivelled to a lug on said plate I49 and works with threaded engagement through ,connected to a shunt switch-actuating lever 450 which, in turn, is pivoted to the base plate I34 at I52. At its free end, the arm 46 is provided with diverging prongs between which the adjacent end of the switch lever I46 is arranged to work in a manner hereinafter described.

The master switch lever I40 at its free end, is shown as provided with a latch lug I56 which, when the said lever is moved to the broken line position, Figs. 24 and 28, will be engaged and held by a free end of a latch dog He. Latch dog 69c is pivoted at I to a bracket I54 secured on the base I34 and is subject to a light spring I56 that normally holds the same against a fixed stop I51 on said bracket. At its intermediate portion, said dog is shown as provided with an offset tripping lug I50.

A tripping magnet or solenoid 350 is mounted on a bracket I54 and acts upon a vertically movable core or tripping plunger 360. At its lower end, plunger 36c is provided with a dog-releasing lug or element He that is pivoted thereto for slight inward swinging movements, but limited in its outward swinging movement. Main lead 530 is connected to the master switch lever I44 by a wire I59 and contact I45 is connected to one terminal of timer coil 43c and to one terminal of one of the coils 3Ic by a wire I60. Terminal of wire I60 is connected by a wire I6I to the other heating coil 3Ic; and the terminals of the two upper coils 3Ic and 3Id are connected to the corresponding terminals of the other set of coils 3Ic3 Id by a wire I62, and fromthe latter point, a wire I63 leads to the main lead 520. A wire I64 connects one terminal of the upper coil 36d to the corresponding terminal of the lower coil 3Id and thence through a switch I65 to a wire I60. This switch I65, as shown, includes a bimetallic strip or warp bar which normally closes the circuit through wire I64 but will open when the temperature of the waille iron reaches a certain predetermined high point suitable for cock-- ing. A signal light bulb I66 is shunted around the switch ,I65, as best shown in Fig. 28, by means of a shunt wire I61.

In Fig. 24, the numeral I68 indicates a gong or bell that is arranged to be struck by the end of a clapper-acting lever I69. Bell I68 is shown as mounted on the base I34 and lever I69 is shown as pivoted on the latter and is subject to a light retracting spring I10. The extended end of lever I69 is in position to be struck by the lug I53 on the end of switch lever I40 when the latter is released and is given quick return from its broken line to its full line position of Figs. 24 and 28.

' Operation of the warfle iron, Figs. 23 to 28 In Fig. 28, full lines indicate the condition of the apparatus or device in what may be treated as normal, that is, when the leads 52c and 530 are connected to a source of current supply by suitable means, such as a socket, but in which the master switch lever I40 is in its normal or released position. At this time, current will flow from lead 53c through lever I40, wires I60 and I6I, to heating coils of the waflle iron and the wire I63 to lead 520. If the waille iron is then idle, that is, not periorming a waflle baking action, the warp switch I65 will be of such temperature that it will break the circuit through the inner heating coils Md, but will leave the circuit closed through the coils 310. This condition of the circult will maintain the plates '01 the'waflle iron in baking condition. In this arrangement, the counpletion of the proper baking or cooking period is indicated by the ringing of the bell or gong.

when the wailie iron is to be thrown into baking action, the master switch lever I 46 will be moved into its dotted line position, Fig. 28, where it will be latched and held by latch dog 300. Current will then flow from lead 53c, through lever I40 through coils 35c and 460, through the heating elements of the waille plates and through wire I63 to lead 620. This will start the waflle baking action and the heating of the timer element 420. Under expansion of element 420, lever 45c will be moved first until its oblique prong engages the adjacent end of lever I46, and then until lever I46 is engaged with contact I 41 and when this occurs, tripping coil 35c and the timer coil or element 43c will be shunted out of action because the current will then take the path of least resistance and flow through lever I46 through the coils of the waiiie plates and through wire I 63 to lead 52c. When timer element 43c is thus shunted out of action, thermally responsive member 420 will commence to cool and contract; but lever I46 will maintain engagement with contact I41 until it has been again engaged by the straight or' upper prong of lever 45c, whereupon the circuit will be broken at contact I41. When contact is broken at I41, the current will then be forced through tripping coil or solenoid 35c and the latter being energized, will raise or attract the plunger 36c, causing lug He by engagement with lug I56, to move latch dog 30c and release lever I40, which latter, being released, will again resume the full line position, Fig. 28, cutting out of action all of the parts of the apparatus, restoring the device or apparatus to the condition first noted.

In the operation of the wailie device just described, the heretofore described variable subinterval is the time required for lever 450, under expansion of element 420, to move lever I46 from any one of several different possible positions into engagement with contact I41; and. the constant sub-interval is the time required under contraction of member 420 to move its oblique lower prong out of engagement and its straight or upper prong into engagement with the adjacent end of lever I46, thereby disengaging said lever I46 from contact I41. Inasmuch as the prongs of lever 450 are divergent, this last noted time can be varied by adjustments of lever I46 toward and from the pivot I52 of lever 45c; and the means for accomplishing this has already been described.

From the foregoing, it is evident that the expressions such as cut-out and cut-off, referring to the supply of electric current or heating medium, is used in a broad and liberal sense and intended to cover such actions whether the heating medium or current be completely out off or so materially cut oi as to modifyor greatly reduce the cookingbr baking action.

It is further evident that in the operation of all of the devices above described, at the termination of the described second or constant subinterval, various actions are produced which indicate the termination of the timed or heat-supplying interval. For instance, the sound produced by the tripping of the mechanism would give such indication, or the ejecting movement of the bread in a toaster, or the observed movement of the parts would give indication of the termination of the timed interval. 4

Obviously, the invention herein disclosed is capable of a wide range of modification within the scope of the invention and within the scope of the claims hereof.

Fig. 29 illustrates a structure or arrangement capable of incorporation in a toaster such as that illustrated in Figs. 1 to 14, inclusive, and wherein certain of the parts that correspond to those of the earlier structure are indicated by the same numerals with the added exponent d. In this structure, the thermally responsive expansible and contractable element 421! is not provided with an individual heating element but is placed between the main heating elements 3ld directly in the line of radiant heat therefrom and in the line of the upwardly moving currents of air induced by convection. This structure will be made clear from the following brief description of the operation, to wit: When the toaster is in normal or cooled condition, and out of operation, master switch 32d will be open, plunger 3611 will be down as shown by broken lines in Fig. 29, switch actuator 33d will be up as indicated by broken lines, and lever d will be engaged with switch contact 48d and will have pressed the same toward the left away from stop Ill a greater or less distance depending on the low temperature of the bar or member 42d. When the toaster is to be thrown into action, actuator 33d is pressed down to the full line position and will there be latched by the dog 39d. Downward movement of the actuator 3911 operating through the mechanism earlier described, will close the master switch 32d. When master switch is thus closed, while lever 45d is engaged with contact 48d, trip magnet 35d will be shunted out and full current will then flow through the heating elements 31d and will continue to thus flow until the element 4211, under the action of the radiant heat from elements 39d, is expanded to such an extent as to first permit spring contact 48d to move against stop Ill and then to move lever 4501 out of engagement with contact 48d, and when this occurs, the current will be caused to flow through trip magnet 35d, thereby raising plunger 36d, releasing the actuator 33d and permitting the same to be moved upward under the action of its spring, earlier described, thereby opening master switch 32d and terminating the toasting action. When master switch is opened, plunger 36 will have dropped back to its lower or dotted line position.

For the next toasting action, it will be assumed that the next toasting action is started by depressing actuator 33d while lever 45d is out of engagement with contact 48d. When this happens, trip magnet 35d will be energized, raising the plunger 36d while actuator is still depressed, thereby permitting dog 39d to again engage and latch the actuator down with the master switch 3241 closed. When this second or repeat action is started, the flow of current through the heating elements 31d will be suflicient to hold plunger 36d raised, but will not be sufficient to produce any material heating of the elements 3Id. Hence the heating elements 3ld will not be again brought into action until element 42d has cooled to a sufficient extent to again engage lever 45d with contact 48d, whereupon, the full current will flow through the heating elements 3Id (through lever 45d and contact 48d) and trip magnet 35d will be shunted out, permitting plunger 36d to drop to broken line position. When, however, under the radiant heat from the elements 39d element 42d is again expanded so as to disengage lever 49d from contact 48d, trip magnet 3511 will be again energized, raising plunger 36d, tripping switch actuator 33d, and causing the master switch 32d to be again opened, thereby terminating this last noted heating or cooking action.

What I claim is:

1. The combination with cooking means including a primary heater and an associated holder for the article to be cooked, of a timer for establishing intervals of time action of said primary heater, said timer including a thermally responsive member, heating means operative on said timer member only until the latter has reached a predetermined high temperature, thereby permitting said member to cool while said first noted heater is still in action, and means for interrupting the action of said first noted heater when and only when said timer member has cooled to a predetermined extent.

2. The combination with electrical cooking means including a'primary electrical heater and an associated holder for the article to be cooked, of a thermostatic timer for establishing intervals of the time action of said primary heater, said timer including a thermally responsive member and an associated secondary electrical heater, a shunting switch actuated by said thermally responsive member, circuit connections and associated means operatively arranged to out said secondary heater out of action when said expansible timer member is heated to a predetermined high temperature, and means for interrupting the action of said primary heater when and only when said timer member has cooled to a predetermined relatively low temperature.

3. The combination with electrical heating means, of a timer for establishing intervals of time action of said heating means, said timer including a thermally responsive member and an electrical heat-radiating element associated therewith, a shunting switch actuated by said thermally responsive timer member, circuit connections including said electric heating means and the electrical element of said timer, a normally open master switch in said circuit connections, a master switch actuator normally opening said master switch, a latch for holding said master switch actuator in a position to cause closing 01' said master switch, and an electromagnetic trip for releasing said latch, said trip including a coil in said circuit connections, the heating element of said timer being in a shunt across the main circuit and said shunt switch being arranged to shunt said heating element out of action when the thermally responsive member of said timer is heated to a predetermined high temperature, and to cause the said tripping magnet to actuate said trip and release said master switch actuator, thereby opening the main switch and cutting off the supply of current to said heating means when the thermally responsive member of said timer cools to a predetermined low temperature.

4. The combination with electrical cooking means, including a primary electrical heater and associated holder for the article to be cooked, of a timer for establishing intervals of time action of said primary heater, said timer including a thermally responsive member and a secondary heat-radiating element associated therewith, circuit connections for supplying current to said primary electrical heater and to the electrical heat-radiating element of said timer, and a timer switch actuated by the thermally responsive member of said timer and arranged to control said circuit connections so as to cut the heating element of said timer out of action, when