US2266024A - Thermal timer for toasters - Google Patents

Description

Dec. 16, 1941. J. R. GoMERsALL l2,266,024

THERMAL TIMER FOR TOASTER'S Filed April 10, 1940 3 Sheets-Sheet l v (ige) /43 /49 78 5 lNvEN'roR ATTORNEY Dec. 16, 1941. J R GQMERSALL I 2,266,024

THERMAL TIMER FOR TOASTERS Filed April 10, 1940 3 Sheets-Sheet 2 z+1- I -Lfu /i'fy-J A l agi gA E i j fis i i: E?" l INVENTOR f i@ c/o/VRGOM-RSALL fm /ff GH laws /HZS' BY 7V/27% ATToRN Y L Dec. 16, 1941. J, R GOMERSALL 2,266,024`

THERMAL TIMER FOR TOASTERS Filed April 1o, 1940 s sheets-sheet s INVENTOR c/oA/RG'QMERSALL ATToRNE Patented Dec. 16, 1941 THERMAL TIMER FOR. TOASTERS .lohn R. Gomersall, Elgin, lll., assignor to McGraw Electric lompany, Elgin, Ill., a corporation of Delaware application April 1o, 1940, serial No. 3284.829

(ci. isi-.16)

. application is to cover more particularly the ther- 8 Claims.

My invention relates to automatic electric toasters and more particularly to thermal timers for such toasters.

An object of my invention is to provide a novel form of thermal timer operating on the heat-up cool-oil` cycle for'controlling the duration of a toasting operation and for terminating the toasting operation.

Another object of my invention is to provide a relatively simple structure for such a thermal timer which comprises a relatively few parts and which can be easily and quickly manufactured and assembled in mass production.

Other objects of my invention will either be apparent from a description of one form of timer embodying my invention or will be pointed out in the course of such description and will be set forth in the appended claims.

In the drawings:

Figure 1 is ay vertical lateral sectional view taken on the line I-i of Fig. 3, the parts being shown in non-toasting position,

Fig. 2 is a fragmentary vertical sectional view taken on the line 2-2 of Fig. 1,

Fig. 3 is a. sectional side elevational view taken onl the line 3-3 of Fig. l the parts being shown in non-toasting position, A i

Fig. 4 is a fragmentary bottom view of the parts shown in Fig. 3 with the bottom cover removed and showing the normal position of certain parts of the timer structure,

Fig. 5 is a fragmentary front view ofthe toaster showing more particularly the manually adjustable knob for regulating the toasting time,

Fig. 6 is what may be called an exploded view of certain parts of the timer and latchstructure. parts being shown as positioned in the same plane although actually they are` positioned in planes extending at right angles to each other,

Fig. 7 is a View similar to Fig. 6, but showing parts of the timer structure in different positions, and.

Fig. 8 is a fragmentary view similar to Fig. 6, showing parts of the timer structure in other positions.

Reference may here be made to my copending application Ser. No. 328,828 led as of even date herewith and assigned tothe same assignee as is the present application in which parts of the toaster structure itself are disclosed. described and claimed, and in the following description of the toaster structure reference will be made to only the maior portions thereof and reference may be had to my above identified copending application for details of thestructure itself. This 55 ward movement of the bread carriers. I provide mal timer means operating on a heat-up cool-oil cycle for each toasting operation.

An automatic electric toaster designated generally by the numeral 2i includes a bottom skeleton frame 23 which may be made oi a suitable moulded composition and which may have asso.

-ciated therewith adjacent its upper edge, a bottom plate 25 which, as shown, may be of inverted open-box shape which may be secured against the upper iace of the skeleton frame 23 in any suitable manner. The toaster includes also a casing 21 which includes two side walls, a front and a rear wall, and a cover, which cover is provided with a. plurality oi longitudinally-extending slots in a manner well known in the art to permit of insertion of slices of bread to be toasted in the toaster and of removing the toasted slices of bread therefrom when they have been properly toasted.

I provide also a plurality of pairs of verticallyextending planar heating elements each including one or more thin sheets 29 ot electricinsulating material such as mica, having wound thereon a heating resistor conductor 3l, all in a manner well known in the art. I provide further a rear intermediate wall 33 and a front intermediate wall 36 which may cooperate with the pairs of spaced vertical electric heating elements to provide one or more toasting chambers within the outer casing 21. I have elected to show my invention as applied to a two-slice toaster but do not desire to be limited thereto as my new and improved thermal timer may be associated with a toaster structure designed and constructed for simultaneously toasting one or any desired number of slices of bread. l

Iprovide a number of bread carriers 31 equal in'number to the numberof toasting chambers, which bread carriers are movable vertically relatively to the above described toast heating elements, the bread carriers being movable from an upper non-toasting position, all in a manner well known in the art.

I provide a single vertical standard 39 having its lower end properly secured as by intertting with vthe bottom plate 25 and by having its upper end held by a bracket Il secured tothe front intermediate wall 35. A carriage plate I3 is vertically movable onthe standard 39 and has lateral rearwardly-extending ilanges I5 at each side thereof to which the front end portions of the bread carriers 31 are connected so that downward movement of the carriage 43 will result in downf ment of the carriage 43 and of the bread carriers connected therewith against the tension of a biasing spring 55 which has its lower end connected to a suitable part of the carriage 43 and which may have. its upper end connected to bracket 4| thereby normally yieldingly biasing the bread carriers into their upper non-toasting asado of connected with the rigid bar 9| and its other end interiitting with a wall of a small casing or box 89 within which the parts of the thermal larly in Figs. l, 6, 'I and 8 of the drawings.

position. In order to maintain the carriage and the bread carriers in their proper operative position relatively to the toasting chamber, I may provide a pair of rollers 51 connected to each of the respective flanges 45, these rollers engaging the front surface of the front intermediate wall' 35 thereby holding the bread carriers as well as the carriage plate in their proper operative positions. 'Ihe front end portions of the bread carriers 31 move in slots 59 in the front intermediate wall 35.

Since the'biasing spring 55 causes quick upward movement of the carriers at the end of a toasting operation, I may provide an air cylinder 6| having its upperend secured to and held The bar 9| has mounted thereon a detentholding and releasing plate III which is longitudinally Ymovable on and relatively to the bar 9|, being secured thereagainst by a plurality of pins |93 fixed in bar 9| and movable in elongated slots |35 in member IUI. A short coil spring |II1 biases member III toward the pivotal support 93 of member 9|. It may be here pointed out that detent i9 is provided with a projection |39 which Member III is further provided at its other end by the bracket 4| and a piston movable therein and mounted on a piston rod 63which has a lost motion connection with thel carriage plate 43 so that when the spring becomes effective to quickly move the bread carriers and the carriage upwardly, the air cylinder 5I will act as a shock absorber in a well known manner.

I provide a latch arm 55 which is pivotally mounted intermediate its endson the carriage plate I3 and which has a lower catch portion 61 adapted to engage with a detent 69 of substantially Lshape pivotally mounted on a bracket 1l! secured to the under side of plate 25. The detent 69 has pivotally mounted thereonfa latch-holding projection 1|, the design and construction of members 69 and 1| being shown substantially in Fig. 1 of the drawings and it will be noted that the member 1| is positioned slightly angularly relatively to a horizontal line or plane and that portion 61 of member l5 also extends slightly angularly relatively to a horizontal plane so that easy and quick separation of the two parts may be eiected when the timer -to be hereinafter described is effective to cause such release and thereby the termination of a toasting operation.

'I'he carriage I3 may have mounted thereon and secured thereto, a resilient support 13 having mounted thereon a contact bridging member 15 which is suitably insulated from the spring member 13 and which is adapted to engage with a is adapted to engage against an end portion of member Ill, the upper surface of portion UI extending angularly as is shown in the drawings forA a purpose which will hereinafter appear.

with a lateral downwardly extending projection ||3 which also has an angularly extending lower surface aswill be notedby reference to Figs. l, 6, 7 and 8 of the drawings.

The bimetal bar 19 has mounted thereon an auxiliary electric heating element |I5 which is suitably insulated from the bimetal bar and which is connected in series circuit relation relatively to the main toast-heating elements hereinbefore described. I further provide a pair of fixed contact members I I1 which contact members are connected to the ends of the auxiliary 'resistor III and which' may be engaged by a contact bridging member I I9 under certain operating conditions to be hereinafter' described. The contact bridging member ||9 is insulatedly mounted on and carried by a flange portion |29 on the pivotally mounted bar 9|. 'A rod 2| extends vertically through the top portion of bottom plate 25 and has mounted thereon xedly relatively thereto. a collar |23. 'I'he lower end of rod |2| is fixed in a laterally extending flange |24 on the movable end of bar 9|. A'biasing Spring |25 has one end thereof engaging a washer |21 surrounding rod I 2| and resting upon the top surface of member 25 while its'upperend engages another washer |29 also loosely mounted on and surrounding the rod I2I, the washer |29 being caused normally to engage fixed collar |23 whereby contact bridging member Il! is biased norpair of contact members 11 insulatedly mounted on and supported against the upper surface of member 25.

The thermal timer more particularly comprising my invention consists of a bimetal bar 19 and a rigid bar 3|, the latter having at one end thereof a laterally off-set portion 33 which is secured to an end portion of the thermal flexible bar 19. The bimetal bar and the rigid bar there- -fore extend normally lsubstantially parallel with mally upwardly and out of engagement with the contact members I I1. The upper end of rod |2| has mounted thereon lloosely a collar |3| which is adapted to be engaged by a projection |33 constituting a part of carriage I3 and extending laterally therefrom. The portion |33 may have an opening therein through which the rod |2I exeach other and are spaced apart a relatively small distance. 'I'he connected ends of the bars 19 and 8| are pivotally mounted as on a :Iixed pivot pin and a short coil spring 31 has one end theretends.` A second lateral projection |35 constiprojection |33 and vof collar I3I to cause a downward bias of the contact bridging member ||8.

At the start oi' a toasting operation the bimetal bar will be in the position shown more particularly in Fig. 1 of the drawings, from which it will be noted that biasing spring 81 causes engagement oi' one face of the bimetal bar 18 with,

projection 85 of bar 8|. Since the auxiliary heater II5 is energized simultaneously with the energization of the toast heating elements, heat will be generated therein and the design and sconstruction of bimetal bar 18 is such that heat received by it from the auxiliary heater II5 will cause it to bow to a position shown for instance in Figs. 6 and '1 of the drawings. Since the free end of bimetal bar 18 is held against projection 85 by biasing spring 81, it is obvious that the bimetal bar on heating will not move bodily but that it will only bow at its intermediate portion substantially as shown in Figs. 6 and "I of the drawings. This results in a turning movement of rigid bar 8| in a counter-clockwise direction as seen in Figs. 6, 'I and 8 of the drawings, and the normal position of projection I|3 is such that rigid bar 8| is positioned therebelow or in other words. projection I|3 on member II1I is out of the path of movement of rigid bar 8| during heating up of the bimetal bar 18. This is because the bimetal bar 18 is supported on a xed pivot pin 85 extending, in the toaster shown in the drawings, in a vertical'direction so that its outer end will support the bar 8| in its initial substantially horizontal position. the upper edge of bimetal bar 18 engaging the lower edge of bar 8| closely adjacent to projection 85.

I provide a manually adjustable stop means for the moving end oi' rigid bar 8|. comprising a shaft I4I having thereon a cam member |43, the shaft |4I extending outwardly through a bearing portion of the skeleton frame 23 and having'mounted thereon an adjusting arm |41 to permit of an operator turning the shaft and the cam |43 thereon in selected direction. Cam |43 is positioned between flange portions |49 secured to or constituting a part of a bar I5I which bar may have elongated slots |53 therein into which iixed pins |55 extend, these pins being securedto one ofthe portions of casing 38. It is therefore obvious that turning movement of arm l|41 will result in turning movement of the cam |43 and movement of the har I5I which is provided with a stop portion |51 at that end thereof adjacent to rigid bar 8|.

Referring now to Fig. s of the drawings, the4 parts of the timer and detent-releasing structure comprising particularly the bimetal bar 18 and the rigid bar 8| are shown in the positions they will occupy when the bimetal bar has been heated and therefore bowed to an extent suiiicient to cause engagement of the rigid bar 8| with the I|8 into engagement with the contact members |I1` whereby deenergization of the auxiliary heating element II5 is eiected. Another result of this turning movement of bar 8|A on its pivot 83 isthat projection |'I3 is now in the'p'ath of the return movement of rigid bar 8| which return movement is caused by the cooling bimetal bar 18 reducing its bowing, with resultant clockwise movement oi' the rigid bar 8|.

It is therefore evident that-coincident with y' cooling ofthe bimetal bar 18, one end of which is pivotally mounted on the pivot pin 85, and the other end of which is pivotally held by interiltting in the recess 88 oi' the bar 8|. the rigid bar 8| will move in a clockwise direction and, Vas shown particularly in Fig. 8 o! the drawings, the movable end of bar 8| will engage projection III when bimetal .bar 18 has cooled to a predetermined temperature. Slight further cooling oi' the bimetal bar 18 causes additional turning movement oi' rigid bar 8| with resultant movement of member IDI until it and particularly its end portion III has been moved out of holding engagement-with portion II|8 of the detent 88. The upward pull on carriage 43 and particularly on arm 85, caused by the biasing spring 55, will therefore result in a turning movement of detent 69 in a clockwise direction with resultant release of portion 81 -therefrom and spring 55 will therefore cause upward movement oi' the carriage 43 and oi* the bread carriers connected therewith.

` It will'be further evident that since compression of the spring |31 will be removed by upward movement of projetcion |33. the downward bias caused thereby will be removed and the bias eifected by spring |25 will again be eil'ective tn cause upward movement of washer 128 against member |23 secured to rod I2| which will result in upward movement of rod I2 oi' contact bridging member I|8 and also of the free end of'bar 8| whereby all of the parts of the timer and detent-releasing structure will be returned to their normal initial or inoperative positions substantially as shown in Fig. 1 of the drawings so that 5 the toaster is ready for the next'succeeding toaststop portion |51. It is to be understood. as already pointed out. that actually the structure to move slightly in a clockwise direction out of y engagement with the edge lportion oi' the bar 8| adjacent to projection 85 thereon and the free end of the bimetal bar 18 can and will then enter the recess 88 whereby downward movement oi' the free end oi' bar 8| will result with attendant downward movement of contact bridging member ing operation.

The structure including more particularly the bimetal bar 18 and the rigid bar 8| may be described as of relatively narrow U-shape and it may beV further pointed out that both ends o! the bimetal bar are substantially viixedly pivotally supported` at one end by the pivot pin 85, and at the other end by engagement with. an edge portion of bar 8| and side engagement with projection 85 oi bar 8|.

As is already well known in the art, in the use of` a single thermally actuable element to constitute the motive power for a timer and for ei'- fecting release of a latch. an auxiliary switch must be operated when the thermal element reaches a maximum desired and predetermined temperature to stop heating oi' the thermal element andto then cause it to cool. One of the simplest forms oi' thermally actuable element has been found by me to be a bimetal bar. When the bimetal bar has then been cooled to a predetermined lower temperature, it must cause.

through` suitable meana'the release or tripping of course. including movement of the toast-heating control switch parts to positions eii'ecting deenergization of the toast-heating elements during the time intervals between toasting operations.

The hereinbefore described thermal timer and detent release means is eiiective to deenergize the auxiliary heating element associated with the bimetal bar at variable temperatures depending upon the position of the stop projection Il'l engaged by the rigid bar Il while the temperature at which termination of a toasting operation is effected is constant as to the cooling bimetal bar 19. f

The 'structure comprising the bimetal bar and the rigid bar provides a relatively light-weight yet easily movable andI relatively strong structure which is pivotally supported at the connected ends of the two bars so that there is relatively littleor no wear of this -pivotal support even after relatively long operation of a toaster, of this kind. Since the auxiliary electric heater Il! does not move through any appreciable distance, it is a relatively simple problem to provide it with ilexible leads connected either directly to the contact members II'I or to bars III and I 8| suitablyinsulatedly Supported in auriliary casing 89 as by a plate lil of electric insulating material.

The hereinbefore described device embodyingl my invention and providing a thermal timing and detent-releasing means requires a minimum number of parts which can be supported in a relatively simple means for the desired movements incident to operation thereof and I have found that adevice of this kind can be easily and quickly assembled in a toaster and it is p08- sible to easily and quickly vary the duration of a toasting operation to thereby provide different degrees of toasting of slices of bread, as may 'be desired by an operator.

While I have illustrated and described a single embodiment of my invention, it is obvious that further changes and modifications may be made therein and I therefore desire that all such modifications as clearly come within the scope of the appended claims shall be considered to be covered thereby.

I claim as my invention: 1. A thermal timer and detent-releasing structure for an automatic electric toaster comprising a toast heating element, a bread carrier movable into toasting and non-toasting positions relatively to the toast heating element and normally yieldingly biased into non-toasting position, means for moving the carrier into toasting position and a detent for holding the carrier in toasting position, said timer and detent-releasing structure including a bimetal bar, a rigid baradjacent one side thereof, means securing one .end of the rigid bar to one end oi the bimetal bar and means pivotally supporting said secured ends, a spring biasing said bars in a given direction about said pivotal support, means including a stop lug engageable by the other end of the bimetal bar to prevent bodily turning movement of the bimetal bar'in saidV given direction on its 2,960,024 A I in the opposite direction. latch means engage-` ablebysaidotherendofsaidbimetalbarto prevent return thereof in said given direction,

pivotal support, an auxiliary electric heater for causing heating of the bimetal bar and bowing thereof to allow said spring to cause turning movement of the rigid bar in said given direction, stop means engageable by said rigid bar when the bimetal bar has been heated to a predetermined temperature eiiective to cause limited bodily turning movement of the bimetal bar means associated with said latchmeans to cause deenergization of the auxiliary heater uponl en- Easement of said bimetal bar with said latch means, cooling of the bimetal bar and decrease of its bowing causing return turning movement of the rigid bar in said oppodte direction. and detent-releaseA means actuable by the returning rigid bar when the bimetalfbar has cooled to a predetermined lower temperature.

2. A device as set forth in claim 1 and including manually operable means to vary the position of the stop means and thereby vary the bimetal temperature -at which the rigid bar en-v gages the stop means. f

3. A thermal timer and detent-releasing structure for an automatic toaster comprising a toast heating element, a bread carrier movable into toasting and non-toasting positions relatively to the toast heating element and normally yieldingly biased into' non-toasting position, means for moving the carrier into toasting position and .a detent for holding the carrier in toasting position. said timer and detent-releasing structure including a bimetal bar, a. fixed pivotal support for one end of said bimetal bar, a stop lug for the other end of said bimetal bar, a rigid bar adjacent one side offthe bimetal bar having one of its ends secured to the pivoied end of said bil metal bar, a spring yieldingly biasing said bars in a given direction on said pivotal support to hold the other end of said bimetal bar against said stop lug, means for exing and unilexing said bimetal bar and for causing turning movement of the rigid bar rst in said given direction and then in the opposite direction bylieating and cooling the bimetal bar and a detent holding means adapted to be actuated by the rigid bar when the same is turning in said opposite direction.

4. A thermal-timer and detent-releasing structure for an automatic electric toaster comprising a toast heating element, a -bread carrier movable into toasting and non-toasting positions relatively to the toast heatingvelement and normally yieldingly biased into non-toasting position, means for moving the carrier into toasting p0- sition and a-detent for holding the carrier in toasting position, said timer and detent-releasing structure including a bimetal bar, a rigid bar normally extending substantially parallel to the bimetal bar, one end of said rigid bar being secured to one end of said bimetal bar, a iixed pivotal support for said secured ends, spring means biasing said bars in a given direction, means holding the other end of the bimetal bar in` substantially fixed position against said bias, said bimetal bar being adapted to be heated and then cooled to cause flexing and imfiexing of the bimetal bar and turning movement of the rigid bar ilrst in said given direction and then in the reverse direction and detent holding means initially out of thepath of movement of the rigid bar when said rigid bar is turning in said given direction and moved into said path of movement when the bimetal bar has reached a predetermined high temperature and engaged by said rigid bar in its movement in the reverse direction when the bimetal bar has cooled to a predetermined lower temperature to cause release f of the detent.

a toast heating element, a control switch therefor yieldingly biased to open position, means for closing said switch and a detent for holding said switch in closed position, said timer and detentreleasing structure including a bimetal bar, a rigid bar normally extending substantially parallel to the bimetal bar, one end of said rigid bar being secured to one end of said bimetal bar, a

fixed pivotal support for said secured ends, a

spring means biasing said bars in a given direc-f metal bar then cooling, said bimetal bar flexing in a given direction when heated to cause turning movement of said rigid bar in said given' direction and flexing in an opposte direction when cooling to cause turning movement of said rigid bar in an opposite direction and detent-holding means initially out of the path of turning movement of said rigid bar and moved into said path of movement when the bimetal bar has been heatedto said given temperature and engaged by said rigid bar when the bimetal bar has been cooled to a predetermined lower temperature to cause release of the detent. i

6. A thermal timer and detent-releasing structure for an automatic electrictoaster comprising a toast heating element, a bread carrier movable into toasting and non-toasting positions relatively to the toast heating element and normally yieldingly biased into non-toasting position,

`means for moving said carrier into toasting p0- sition. and a detent for holding the carrier in toasting position, said ltimer and detent-releasing structure including a bimetal bar, a xed pivotal support for one end of said bimetal bar, a

stop lug for the other end of said bimetal bar,

spring means for yieldingly biasing said bimetal bar against said stop lug, said bimetal bar being adapted to be heated and then cooled to cause iiexing and unlexing thereof, means fixedly secured toV the pivotally secured end of said bimetal bar and turnedby the bimetal bar when heating in one direction and then turned by the bimetal bar when-cooling in the opposite direction and detent releasing means engageable by the means xedly secured to the pivotally mounted end of the bimetal bar when the bimetal bar has cooled to a given temperature.

7. A thermal timer and detent-releasing structure for an automatic electric toaster comprising a toast heating element, a control switch for said toast heating element normally yieldingly biasedto open position, means to cause closing of said switch to initiate a toasting operation and a detent for holding said switch closed, said timer and detent-releasing structure including a bimetal bar, a rigid bar normally extending substantially parallel to the bimetal bar,'one end of said rigid bar being secured to one end of said bimetal bar, a fixed pivotal support for said secured ends, spring means biasing said bars in a given direction, means holding the other end of the bimetal bar in substantially iixed position against said bias, means to heat said bimetal bar, means to stop heating thereof when it has reached a given high temperature, the bimetal bar flexing while being heated and causing said rigid bar to turn in said given direction and then cooling when heating thereof has stopped and causing said rigid bar to turn in the opposite direction and detent holding means initially out of the path of movement of the rigid bar when it is turning in said given direction and moved into said path of movement when the bimetal bar has reached said given high temperature and engaged by said rigid bar in its movement in the reverse direction whenthe bimetal bar has cooled to a given lower temperature to cause release of the detent.

8. A thermal timer and toasting-operationterminating structure for an automatic electric toaster comprising toast heating elements and means for initiating a toasting operation, said thermal timer and toasting operation terminat-l ing structure including a bimetal bar, a pivotal support for one end of said bimetal bar, a rigid b r normally extending substantially parallel th said bimetalbar. one end of said rigid bar being secured to the pivotally supported end of the bimetal bar, spring means biasing said bars in a given direction, means holding the other end of said bimetal-bar in substantially xed position against said bias, means to heat said bimetal bar, means actuable by the bimetal bar to stop heating thereof when it has reached a given temperature, the bimetal bar exing while being heated to cause turning movement of the rigid bar in said given direction and then cooling when heating thereof has stopped and causing said rigid bar to turn in the opposite direction and terminate a toasting operation when the bimetal bar has reached a given lower temperature.

JOHN R. GOMERSALL.

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