US2301070A

US2301070A - Toaster

Info

Publication number: US2301070A
Application number: US358737A
Authority: US
Inventors: Joseph W Myers
Original assignee: Proctor and Schwartz Inc
Current assignee: Proctor and Schwartz Inc
Priority date: 1940-09-27
Filing date: 1940-09-27
Publication date: 1942-11-03
Anticipated expiration: 1959-11-03

Description

Nov. 3, 1942. w, MYERS 2,301,070

TOASTER' Filed Se pt. 27, 1940 4 Sheets-Sheet 1 J. W. MYERS Nov. 3, 1942.

TOASTER Filed Sept. 27, 1940 4 Sheets-Sheet 2 J. w. MYERS Nov. 3, 1942.

TOASTER Filed Sept. 27, 1940 4 Sheets-Sheet 3 NOV. 3' 1942.

4 sh s-Sheet Mr J gw Patented Nov. 3, 1942 I Joseph W. Myers,

TOASTER I I Philadelphia, Pa.,' assignor to Proctor & Schwartz, Inc., Philadelphia, Pa., a corporation of Pennsylvania Application September 27, 1940, Serial No. 358,737

19 Claims.

This invention relates to automatic electric bread toasters and has for its principal object to provide an improved device of this general character.

A more specific object of the invention is to provide an improved automatic toaster wherein the toasting operation is automatically terminated and the bread is moved to a discharge position when it has been toasted to the desired degree.

Another object of the invention is to provide a novel toaster wherein the termination of the toasting operation is controlled by a rapidly expansible and contractible element in response to heating and cooling of the said element. v

A further object of the said invention is to provide a novel toaster of this character, wherein the heating and cooling of the control element is effected by passing current therethrough and by controlling the current by means of a thermostatic switch preferably controlled directly from a bread slice being toasted.

Another object of the invention is to provide novel means operable at will to render the automatic mechanism inoperative, thereby to enable the making of so-called Melba toast.

Other objects and features of the invention will appear hereinafter.

In the accompanying drawings,

Fig. l is a perspective view of a toaster embodying the invention;

Fig. 2 is a sectional perspective view illustrating the thermostatic control mechanism;

Fig. 3 is an end view of the toaster with the cover removed, and with the parts in inoperative position;

Fig. 4 is a partial side view ofthe device taken from the left-hand side of Fig. 3;

Fig. 5 is an end view of the device similar to Fig. 3, but showing the parts in operative position;

Fig. 6 is a partial side view taken from the right-hand side of Fig. 5;

Fig. 7 is a perspective view illustrating the novel mechanism of the invention; and

.Fig. 8 is a diagrammatic illustration of the electrical circuit.

Referring first to Fig. 1, there is shown a toaster of the two-well type, and designated generally by reference character I, the bread wells being shown at 2 and 3. The controls extend from an end of the device as illustrated. At 4 there is shown a manually rotatable control knob, by means of which the toaster is adjusted to effect different degrees of toasting of the bread. At 5 there is shown a depressible knob, by means of which the bread carriage is moved to its toasting position. At 6 there is shown a depressible knob, by means of which the latch for the bread carriage may be released at will. At 1 there is shown a two-position control knob, by means of which the toaster may be operated in the normal manner, or it may be operated to obtain so-called "Melba toast.

Referring now to Fig.2, the general construction of the toaster and the thermostatic control mechanism thereof, is preferably similar to that disclosed and claimed in the Myers and Stevenson Patent No. 2,179,422, granted November, 7, 1939. For the purposes of the present invention, it will be unnecessary to describe this structure in great detail. Briefly, the heating elements are shown generally at 8. The bread carriage is shown at 9, and comprises elements slidably mounted with reference to the vertical rods Ill. The thermostatic element is shown at H, and is adapted to engage a bread slice, represented at l2, and the thermostatically-controlled switch is shown at Hi. This switch is adjustable by means of the knob 4, which is operable through the slotted cam 14 and arm I5 to adjust the switch l3 relative to the thermostatic ele ment H. This thermostatic control mechanism also includes a compensating thermostatic element IS. A detailed description of this mechanism is set forth in the above mentioned patent.

Referring now to Figs. 3 to 7, and particularly Fig. 7, the framework of the toaster includes an end plate I! and a base plate l8, with which the mechanism now to be described is associated. The bread carriage includes, as a part thereof, a plate is which is slidable along a vertical support and guide post 20. The knob 5, previously mentioned, is carried by an extension 2| turned out from the body of plate is. A spring 22 has its lower end secured to extension 23 on plate 19, while the upper end of the spring is anchored to the top plate 24 of the framework. This spring urges the bread carriage upward to its discharge position. By means of the knob 5, the carriage may be moved downward against the action of spring 22 to its toasting position. The carriage is held in its toasting position by means of a pivoted latch 25, the hooked end 25 of which is adapted to engage a cooperating latch member 21 extending from the plate l9. Immediately adjacent the pivoted latch member 25 is a pivoted latch-tripping member 28, which carries the knob 6 on its forwardly extending end, The tripping member 28 is thus arranged to engage an extending lug 28 on the latch member 25. A leaf spring 38 is secured to the base plate l8 and has projecting'ilngers 3| and 32 arranged to resiliently engage the members 28 and respectlvely. Thus the said members are urged toward latching position. Whenever it is desired to trip the latch manually, the knob 6 is depressed, thereby rocking the latch member 25 to release the bread carriage, permitting the spring 22 to remove the carriage to its discharge position.

In accordance with the invention, the latch tripping member 28 is automatically controlled by the operation of a ratchet and pawl device. The tripping member 28 is formed to provide an inclined toothed edge 33 thereon, the teeth of which project downwardly. Associated with this ratchet is a pawl member 34 carried at the lower end 38 of a vertical bar 35. The bar 35 is slotted at 33 to accommodate an extension 31 of the tripping member 28 above the teeth 33. The extension 31 is adapted to abut against a stop 38, formed integrally with the end plate l1. Thus the stop 38 limits the clockwise movement of the tripping member 28, as viewed in Fig. 6.

The bar 35 is provided with an aperture near I its upper end and is suspended on a hook 40 on the end of a transverse lever 4|. A spring 42 has its upper end secured to the upper turned end 43 0! bar 35, while the lower end of this spring is anchored to a turned out lug 44 on plate I1. Thus the spring 42 tends to urge the bar 35 downward, and by virtue of its arrangement, the spring also tends to rock the bar 35 slightly out ward about its pivotal mounting point at 40. This action of the spring tends to bring the pawl 34 into engagement with the ratchet teeth 33. When the bread carriage is in its raised inoperative position, the extension 21 bears against the upper portion of bar 35 and maintains the pawl 34 out of engagement with the teeth. However, when the bread carriage is moved downward to its toasting position, the bar 35 is released by virtue of the lower portion thereof being offset and free of engagement with the extension 21.

The action of bar 35 is controlled by the lever 4|, which is mounted for slight pivotal movement on an extending ear 45 on the plate [1. To this end, the lever 4| is seated in a slot in the car 45. Adjacent its mounting point, and at its end, the lever 4| has a lateral extension 46, upon which there is mounted an insulating saddle 41. A wire-like element 48 is looped about the saddle 41 and seats in a groove therein, and the ends of this element are secured to

stationary terminals

48 and 58 mounted on an insulating block 5| on the plate I1. The terminal 48 also has secured thereto a resilient contact member 52 whose forwardly extending end 53 constitutes one element of a switch. To this end the portion 53 carries a contact which is adapted to engage an associated stationary contact 54 mounted on the base plate I8. A finger 55 is turned out from the contact member 52, and is engageable by an insulating disc 56 carried by the carriage plate l8. Normally, the disc 56 is out of engagement with the switch, and the resilience of the contact member 52 maintains the switch contacts in open position. When the carriage is lowered, however, the disc 56 engages the finger 55 and presses it downward, and this action brings the upper switch contact into engagement with the lower switch contact with a wiping action. This insures good electrical contact between the switch elements.

The wire element 48 is current-conductive and is of such character that it heats and expands rapidly when current is passed through it, and it cools and contracts very rapidly when the current is' interrupted. Preferably this element is formed of resistance wire known commercially as grade #0 wire, which is composed oi 60% nickel, 16% chrome and 24% iron. 01! course, any other suitable material may be used,

As may be seen in Fig; 8, the thermostatic switch I 3, the switch 53-54 and the element 48 are serially connected in the toaster circuit along with the heating elements 8. In operation, the switch 53-54 is maintained closed as long as the bread carriage is latched in its toasting position. From Fig. 7, it may be seen that expansion of the element 48 will tend to permit the spring 42 to move the bar 35 downward, while contraction oi the element 48 will tend to rock lever 4| counterclockwise and thus tend to raise the bar 35 against the action oi! spring 42.

The operation of the mechanism may now be clearly understood by considering the complete cycle of operation of the toaster. Assuming that the thermostatic switch l3 has been adjusted by knob 4 to give the desired degree of bread toasting, and assuming that the bread carriage has been lowered by means of knob 5, the toasting operation proceeds with the carriage in latched position and with the switch 53-54 closed. During the toasting operation, the element 48 is heated by the current flowing therethrough and expands, causing downward movement 01 the bar 35. At the same time the pawl 34 is brought into engagement with the teeth 33. as described above. When the thermostatic element II has deflected sufiiciently to open the switch 3, the current is interrupted and the element 48 cools and contracts very rapidly, causing a slight upward movement of bar 35. This rocks the trip member 28, thereby disengaging the latch 25 from extension 21 and permitting spring 22 to lift the carriage 9 to its discharge position. At the same time switch 53-54 opens and prevents reclosure of the circuit until the next operation.

A further feature of the invention resides in the provision of the manual control 1, by means of which the above described mechanism may be rendered inoperative. A member 51, in the form of a heavy piece of wire, is loosely wound about the post 20 and carries the knob 1 at one end. The opposite end portion 58 of this member is disposed in cooperative relation with the lower portion of bar 35. Thus the member 51 is pivotally mounted on post 28 and the end 58 may be swung outward or inward with respect to bar 35. The cover of the toaster is formed to provide two recesses 59 and 80, in each of which the control end of member 51 may be disposed. These recesses are designated respectively, Pop up and Melba. When the member 51 is latched in position 59, it permits the above described automatic operation of the device. However, when the said member is latched in position 50, the end 58 engages the bar 35 and holds it out of engagement with the ratchet teeth, thereby rendering the mechanism inoperative. During such operation the toasting will continue under the control of thermostat il until it is manually interrupted. As indicated above, the purpose of this is to enable the making of socalled "Melba toast.

From the above description and the accompanying illustrations, it will be seen that the invention provides a novel toaster construction embodying a novel control mechanism for automatically controlling the toasting operation. Further, it will be seen that various other novel features are embodied in the device.

It will be apparent that the invention is not limited to the specific structure illustrated. but is capable of various modifications within the scope of the appended claims.

I claim:

1. In an automatic toaster, means movable between two positions to initiate or interrupt the toasting operation, means urging said movable means toward its inoperative position, latch means for holding said movable means in its op erative position, a latch-tripping mechanism, a, current-responsive wire element whose length varies under the influence of current-generated heat, said element being characterized in that it cools and contracts very rapidly upon interruption of the current supplied thereto, means for energizing said element during the toasting operation and for deenergizing said element when the desired degree of toasting has been reached, and means controlled by said element for conditioning said latch-tripping mechanism during the energization of said element, and for actuating said mechanism in response to the rapid contraction of said element immediately following the deenergization thereof.

2. In an automatic electric toaster, a bread carriage movable between a toasting position and a bread discharge position, meansurging said carriage toward its discharge position, latching means for holding said carriage in its toasting position against the action of said last-named means, a thermal-responsive current-operated expansible element included in the toaster circuit, said element being characterized in that it cools and contracts very rapidly upon interruption of the current supplied thereto, a thermostatic switch serially connected with said element in the toaster circuit, said switch including a thermal element responsive to the degree of toasting, whereby the opening of said switch deenergizes said element when the desired degree of toasting has been reached, and means operable by the rapid contraction of said element to release said latching means immediately following the deenergization of said element.

3. In an automatic electric toaster, a bread carriage movable between a toasting position and a bread discharge position, means urging said carriage toward its discharge position, latching means for holding said carriage in its toasting position against the action of said lastnamed means, a thermal-responsive current-operated expansible element included in the toaster circuit, said element being characterized in that it .cools and contracts very rapidly upon interruption of the current supplied thereto, a thermostatic switch serially connected with said element in the toaster circuit and including a thermomotive member arranged to be afiected by the surface temperature of a bread slice being toasted, thereby to respond to the degree of toasting, whereby the opening of said switch deenergizes said element when the desired degree of toasting has been reached, and means operable by the rapid contraction of said element to release said latching means immediately following the deenergization of said element.

4. In an automatic electric toaster, a bread carriage movable between a toasting position and a bread discharge position, means urging said carriage toward its discharge position, latching means for holding said carria e in its toasting position against the action of said last-named means, tripping meansxior releasing said latching means, comprising ratchet teeth and an associated reciprocable pawl, means continuously urging said pawl into engagement withsaid ratchet teeth, a thermal-responsive element adapted to expand and contract rapidly when heated and cooled, said pawl being actuable through a stroke and return stroke by said element upon heating and cooling of the latter, so that the pawl releases said latching means on its return stroke, and means for effecting successive heating and cooling of said element.

5. In an automatic electric toaster, a bread carriage movable between a toasting position and a bread discharge position, means urging said carriage toward its discharge position, latching means for holding said carriage in its asting position against the action of said la. named means, a ratchet and pawl tripping m ehanism for said latching means, means continuously urging the pawl into engagement with the ratchet, a thermal-responsive element adapted to expand and contract rapidly when heated and cooled, said pawl being actuable through a stroke and return stroke by said element upon heating and cooling of the latter, so that the pawl releases said latching means on its return stroke, means for effecting successive heating and cooling of said element, and means on said carriage for disengaging said pawl from said ratchet teeth when the carriage moves to its discharge position.

6. In an automatic toaster, electrical heating means for toasting bread slices, a heat-responsive expansible element characterized in that it cools and contracts very rapidly upon interruption of heating of the same, means for heating said element coincident with the operation of said first-mentioned heating means, thermostatic -means responsive to the degree of bread toasting for interrupting the heating of said element when the bread has been toasted to a desired degree, and means operable by the rapid contraction of said element for stopping the toasting operation immediately following the interruption of heating of said element.

7. In an automatic toaster, electrical heating means for toasting bread slices, a heat-responsive current-operated expansible element characterized in that it cools and contracts very rapidly upon interruption of heating of the same, a thermostatic switch serially connected in circuit with said element, said switch including a thermal element responsive to the degree of toasting of the bread slices, whereby the opening of saii switch deenergizes said element when the bread has been toasted to a desired degree, and means operable by the rapid contraction of said element for stopping the toasting operation immediately following the deenergization of said element.

8. In an automatic toaster, electrical heating means for toasting bread slices, a heat-responsive current-operated expansible element characterized in that it cools and contracts very rapidly upon interruption of heating of the same, a thermostatic switch serially connected in circuit with said element and including a thermomotive member arranged to be affected by the surface temperature of a bread slice being toasted, thereby to respond to the degree of toasting of the bread slices, whereby the opening of said switch deenergizes said element when the bread has been toasted to a desired degree, and means operable by the rapid contraction of said olemeat 'for stopping the toasting operation immediately following the deenergization 01' said element.

9. In an automatic toaster, electrical heating means for toasting bread slices, 0. heat-responslve expansible element characterized in that it cools and contracts very rapidly upon interruption of heating of the same, means for heating said element coincident with the operation of said first-mentioned heating means, means including a second heat responsive element for in terrupting the heating or said first element when the bread has been toasted to a desired degree. means operable by the rapid contraction of said first element for stopping the toasting operation immediately following the interruption of heating of said first element, and means operative at will to render said stopping means inoperative and thereby cause the toasting operation to continue.

10. In an automatic toaster, electrical heating means for toasting bread slices, 9. heat-responsive current-operated expansible element connected in circuit with said heating means, said element being characterized in that it cools and contracts very rapidly upon interruption of the current supplied thereto, a thermostatic switch connected in circuit with said heating means and said element, said switch being arranged to respond to the degree of toasting so as to deenergize said heating means and said element when the surface of the toast has reached a predeter mined temperature and to reenergize said elements when the surface of the toast falls below said temperature, means operable bythe rapid contraction of said element for stopping the toasting immediately following the deenergizatlon of said element, and means operative at will to render said stopping means inoperative and thereby cause the toasting operation-to continue at a reduced rate under control of said thermostatic switch.

11. In an automatic electric toaster, a bread carriage movable between a toasting position and a bread discharge position, means urging said carriage toward its discharge position, latching means for holding said carriage in its toasting positlon' against the action of said last-named means, tripping means for releasing said latching means, comprising ratchet teeth and an associated reciprocable pawl, means continuously urging said pawl into engagement with said ratchet teeth, a thermal-responsive expansible element normally holding said pawl in ineflective position but adapted when expanded to permit said pawl to engage the ratchet teeth, said element being operable by its contraction to move the pawl in a direction to release the latching means, and means for heating said element during the toasting operation and for interrupting the heating of said element when the toasting has progressed to the desired degree, whereby said latching means is released by the contraction of said element to terminate the toasting operation.

12. In an automatic electric toaster, a bread carriage movable between a toasting position and a bread discharge position, means urging said carriage toward its discharge position, latching means for holding said carriage in its toasting position against the action of said last-named means, tripping means for releasing said latching means, comprising ratchet teeth and an associated reciprocable pawl, means continuously urging said pawl into engagement with said ratchet teeth, a lever having one end attached to said connected to the opposite end of said lever for actuating the same, said element normally holding said pawl in ineflective position but adapted by its expansion to permit the engagement of said pawl with said ratchet teeth, said elem being operable by its contraction to move lever in a direction to eiiect tripping motion of said pawl, and means for heating said element during the toasting operation and for interrupting the heating 01 said element when the toasting has progressed to the desired degree, whereby said latching means is released by the contraction of said element to terminate the toasting operation.

13. In an automatic toaster, means movable between two positions to initiate or terminate the toasting operation, means urging said movable means toward its inoperative position, means ior latching said movable means in its operative position, a current-conductive thermal-responsive element, means for supplying current to said element during the toasting operation, means for interrupting the current flow in said element when the desired degree of toasting has been reached, and means operable by said element immediately following the cessation of current flow therethrough for releasing said latching means, thereby to terminate the toasting operation.

14. In an automatic toaster, means movable between two positions to initiate or terminate the toasting operation, means urging said movable means toward its inoperative position, means for latching said movable means in its operative position, a current-conductive thermal-responsive element, means for supplying current to said element during the toasting operation, a thermostatic switch including a thermal member responsive to the degree of bread toasting for interrupting the current flow in said element when the desired degree of toasting has been reached, and means operable by said element immediately following the cessation of current flow therethrough for releasing said latching means, thereby to terminate the toasting operation.

15. In an automatic toaster, means movable between two positions to initiate or terminate the toasting operation, means urging said movable means toward its inoperative position, means for latching said movable means in its operative pawl, a thermal-responsive expansible element position, a current-conductive wire element whose length increases rapidly when current flows therein and decreases rapidly when the current fiow is interrupted, means for supplying current to said element during the toasting operation, means for interrupting the current flow in said element when the desired degree of toasting has been reached, and means operable by said element immediately following the cessation of current flow therethrough for releasing said latching means, thereby to terminate the toasting operation.

16. In an automatic toaster, means movable between two positions to initiate or terminate the toasting operation, means urging said movable means toward its inoperative position, means for latching said movable means in its operative position, a current-conductive wire element whose length increases rapidly when current flows therein and decreases rapidly when the current flow is interrupted, means for supplying current to said element during the toasting operation, a thermostatic switch operable by the temperature of a bread slice being toasted for interrupting the current flow in said element when the desired degree of toasting has been reached, and means operable by said element immediately following the cessation of current flow therethrough for releasing said latching means, thereby to terminate the toasting operation.

17. In an automatic toaster, a bread carriage movable between a toasting position and a bread discharge position, means urging said carriage toward its discharge position, latching means for holding said carriage in its toasting position against the action of said last-named means, a normally inoperative latch-tripping mechanism, a heat-responsive expansible element characterized in that it cools and contracts very rapidly upon interruption of heating of the same, electrical means for heating said element during the toasting operation, thermostatic means responsive to the degree of bread toasting for interrupting the heating 0! said element when the desired degree of toasting has been reached, and means controlled by expansion and contraction or said element for rendering said latch-tripping mechanism operative and for actuating said mechanism during the successive expansion and contraction movable means toward its inoperative position. latching means for holding said movable means in its operative position, said latching means including a movable member having ratchet teeth thereon, a pawl cooperatively associated with said ratchet teeth, means including a thermal ele-.

ment for causing said pawl to engage said ratchet teeth and release said latching means to terminate the toasting operation, and means responsive to the degree of toasting for controlling the thermal energization of said element.

19. In an automatic bread toaster, means movable between two positions to initiate or terminate the toasting operation, means urging said movable means toward its inoperative position, a movable latching member for holding said movable means in its operative position, a movable trip member arranged cooperatively with said latch member and having ratchet teeth thereon, a pawl cooperatively associated with said ratchet teeth, means including a thermal element for causing said pawl to engage said ratchet teeth and actuate said trip member to terminate the toasting operation, and means responsive to the degree 0! toasting ior controlling the thermal energization of said element.

JOSEPH W. MYERS.