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Патент USA US2412727

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Dw- >1 7,1945-
J. R. GoMERsALL ' ET AL
2,412,727
AUTOMATIC ELECTRIC TOÀSTER COMPENSATOR FOR
VARIABLE VOLTAGE CURRENT SUPPLY
" Filed Feb. 16’, 1942
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INVENToRs.
-MUHRA Y/RELAND
BY »vz/MM
ATTORNEY
'
Dm 17» 194.5
J. R. _GoMERsALL Erm.
AUTCMATIC ELECTRIC TOASTER COMPENSATOR FOR
VARIABLE VOLTAGE CURRENT SUPPLY
Filed Feb. 1s, 1942
2,412,727
:ay sheets-sheetvz
ATTORNEY
Patented Dec. 17, i945
2,412,727
UNITED STATES `P’A'I’EN'I‘ OFFICE
2,412,727
AUTOMATIC ELECTRIC 'JTÍOASTERv COMPEN
SATOR FOR VARIAB
RENT SUPPLY
LE VOLTAGE CUR
John n. Gomersali; Elgin, and Murray Ireland,
near Elgin, Ill., assignors- to McGraw Electric
Company, Elgint Ill-.,»a corporation of Delaware
Application February 16, 1942,'¿Serial No.V 431,088
1
5 Claims.
Our invention relatesl to electric cooking de
vices and particularly to automatic elect'ricï
toasters.
An object ci our invention is'to provide means
applicable to an automatic electric toaster which
will compensate for the e?ïect of a variable voltage
current supply energizing the toast heating ele
(Cl. 219-19)
2
toaster assembly Il which comprises a moulded
skeleton frame i3 and an outside casing l5 which
in general are of the type which have been made
and soldv heretofore. The outside casing l5 has
an open upper end portion in which there islo
cated atop closure member ll which, as shown
ments.
more particularly in Fig~ 3 of the drawings, is
provided` with a bread-slice inserting and toast
Another object of our invention is to provide
removing opening is, in a- manner now well
an automatic electric toaster that may be con
nected to energizing circuits of appreciably dif 10 known in the art. The toaster assembly is pro
vided further with a relatively thin sheet metal
ferent voltages and which will provide substan
bottom plate 2l` suitably secured against the up
tially the same degree oi toasting for different
per surface of the frame i3 and the bottom edge
slices of bread.
portions of the casing I5 may be secured either
Another object of our invention is to provide a
new method for toasting slices of bread compris 15 against the bottom plate 2l or the moulded base
ing the steps of limiting the maximum tempera
i3 as may be found desirable or suitable.
Qur toaster assembly includes further a pair
of spaced'vertically extending planar toast heat
ing elements 23 and 2d which may be held in their
the heat for a preset and iixed length of time. _
Another object of our invention is to provide 20 proper operative positions within the casing by
any suitable or desired means not pertinent to
relatively simple means which will ensure that,
ture of the heat applied to the slice or slices of
bread and subjecting the bread to the action of
for a given setting of the control elements of an
automatic electric toaster, substantially the same
amount of heat from the toast heating elements
will reach or aii‘ect the slice or slices of bread
being toasted, irrespective of the voltage of the
supply circuit to which the toast heating ele
ments are connected.
Other objects of our' invention Will either be
apparent from a description of one form embody
ing our invention or will be pointed out in the
course of such description and set forth in the
appended claims.
In the drawings:
Figure 1 is a longitudinal vertical sectional View
through a toaster embodying our invention,
Fig. 2 is a horizontal sectional View on the line
2-2 oi’ Fig. l,
nor constituting a part of our invention. in order
to properly center a slice of bread while it is
toasting in a vertical position between he toast
heating elements
and 25 We provide guard or
guide wires 2l the lower ends of‘which may ex
tend through the base plate 2l and the upper re
turn-bent end portions may be supported by lon
gitudinally extending topirame plates 29 or inv
any other suitable or desired manner. A strand
of resistance conductor 3l may be wound on rel
atively thin sheets of electric insulating material,
such as mica, which constitute a part of the toast
heating elements 23 and 25.
We provide further bread carriers 33 extend
ing substantially horizontally between the spaced
toast heating elements and the iront end of such
bread carrier may be rigidly connected with a
Fig. 3 is a vertical sectional View taken on the 40 ?lrstfcarriage- Süß-of substantially L-shape, whichy
carriage-ìs--provided at its upper and at its lower
ends with guide-bushings 3l adapted to move ver
Fig. 4 is a vertical sectional view taken on the
line 3_3 of Fig. l,
line 4-4 of Fig. l,
Fig. 5 is a diagram of the electrical connections
showing the position of the contacts while-still
at lower temperature, and,
Fig. 6 is a diagram of the electrical circuits
showing the parts of Fig. 5 after having been
heated to a given temperature.
We have elected to show our invention and 50
particularly the novel elements thereof as applied
to a single-slice automatic electric toaster but it
is to be understood that our invention may bev
applied to other types of toasters.
We have illustrated an automatic electricl 55
The
tically
lower
reciprocally
end'of thison
standard
a vertical
may standard
be supported
by the base plate 2| while the upper end thereof
may be supported» by a small bracket lil, all in a
manner well known in the art.
We provide further a second reciprocally mov
able carriageßê, which second carriage is pro
vided with upper and lower bearing bushings 45
which are adapted to move on the vertical stand
ard 3d;
We provide a main switch for the toast heating
elements,` which switch comprises a pair of con
tact‘- members 41 insulatedly supported in proper
operative'position on the base plate 2l near its
2,412,727
3
4
operator, such as “medium,” for example will
i
front edge portion. Carriage 35 is adapted to
support a contact bridging member t9 insulated
, cause successive slices of bread of the same kind
to receive substantially the same browning or
degree of toasting as long as the temperature of
the toaster remains at the same value.
ly secured to a resilient member 5l which mem
ber 5i is carried by and moves with the first men
tioned carriage 35. When the carriage 35 is
In case, however, the energizing supply circuit
moved to its lowermost position, contact bridging
voltage is much lower, a similar slice of bread
member li@ will engage the contact members d1
to thereby close an energizing circuit through the
toast heating elements, it being assumed, of
course, that .the toast heating elements are elec
trically connected by means of a twin conductor
would be toasted only to the light degree and,
therefore, the operator would have to change the
setting of the timing mechanism to lengthen
the toasting operation and thereby obtain the
desired medium degree of toasting.
If medium toast was desired and had been ob
cord 53 with a suitable source of supply of elec
tric energy.
tained in a toaster operated on a 115 volt cir
cuit and which was then connected to a 125 volt
The bread carrier is normally yieldingly biased
to an upper non-toasting position by means of a
tension coil spring 55 one end of which is con
circuit, the degree of toasting would probably be
that usually called “dark” .if indeed it might not
nected to carrier 33 or carriage 35 While the other
be black or burnt.
end thereof may be connected to bracket 4 I.
It is to be noted further that the ñrst slice of
The second carriage plate 43 is provided with
bread to be toasted, starting with a cold toaster,
20
a forwardly-extending portion 5'1 which is of
will not be as dark or as well toasted as will, say,
such length as to extend outwardly beyond the
the third, fourth or ñfth slice of toast when the
front portion of the casing i5 is through a slot
toaster is operated with but small time intervals,
59 therein and an actuating knob 3l is secured to
on the order of say five seconds between the suc
the arm 5l so that an operator may press down
wardly on knob 6I to cause downward movement
cessive toasting operations.
A number of different inventions have been
made .and applied to toasters of .the various kinds
of carriage d3, carriage 35, and the bread carrier
when it is desired to move the bread carrier into
now on sale which effect what is usually called
a compensation for not only the variation of the
its lowermost toasting position.
' We provide also a suitable timing mechanism
eifect of the different temperatures under which
63 here shown as including a spring-driven train
a toaster will operate because of quickly succes
sive operations, but also to take care of the fact
that different toasters assembled and tested in
.the factory at a selected standard voltage, may
be operated at much lower or much higher volt
of gears of the general kind shown in Ireland
Patent No. 1,866,808 but it is to be understood
that any other timer which will operate for an
adjustably preset i'lxed length of time may be
used in place of such mechanical timer. An ad
justing knob Se may be provided, by which the
operating period of the timer may be manually
varied. The timer mechanism E3 is held in
proper >operative position by a bracket 65.
The .timer is provided with a lever detent mem
ber 51 pivotally mounted on the timing mecha
ages by different purchasers of similar toasters
made by the same manufacturer. Thus, if it be
assumed that one toaster may operate on a 100
volt supply circuit at one time and may operate
40 on a 125 volt supply circuit at another time, it
is evident that the amount of energy translated
into heat at .the higher voltage is over fifty pre
nism 33 near the lower end of the lever and an
cent greater than that translated into heat at
end portion E9 is provided on the lever 61 at its
the lower voltage. The parts now ~to be described
lower end which portion 55 is adapted to be en
and constituting more particularly our inven
gaged by a laterally projecting portion ‘il con
tion provide compensating means which may be
stituting a part of or secured to the ñrst carriage
considered to be 100% effective to take care of
35. Thus when carriage 35 is moved downward
variations in the temperature of .the toaster as
lY, as hereinbefore described, it Will engage the
well as taking care of different supply circuit
portion e9 and be held in its lowered position, that
voltages.
50
is, with the carrier in its toasting position for
We provide a bimetal member “i5 which in the
such length of time as may be determined by .the
present embodiment is preferably made of sub
operation of the timing mechanism 63.
stantially U-shape and is connected in electric
The timing mechanism E3, when it is of the
series circuit with the toast heating elements 23
type disclosed in Patent No. 1,866,808, will be
and 25. We prefer to mount the compensating
55
wound up when carriage member 43 is moved
bimetal strip or bar 'i5 out of close thermal com
downwardly and the construction is such that the
munication with the body of the toaster and par
carriage member 43 will be moved upwardly with
ticularly of the toast heating elements and
the returning part of the mechanical timer as
therefore locate it below the base plate 2i which
clearly described in the above mentioned patent
60 is provided with a Ventilating opening îî imme
and when a release portion 'I3 on carriage 43 en
gages a roller l5 mounted on the upper end of
lever (il, latch member ‘H will be released from
detent lever 61 and the spring 55 will cause quick
upward movement of the carrier into its non
toasting position.
The parts of the toaster hereinbefore described
are those which constitute a standard toaster,
large numbers of which have been made and sold
and it is to be understood that the timing mech
anism 63 has mounted thereon means permit
ting of varying its time of operation so that light,
medium or dark toast may be obtained and as
long as the toast heating elements are subjected
to substantially the same energizing supply cir
cuit voltage, say 115 volts, any one setting by an
diately above the bar 15 so that air will be drawn
inwardly through a properly perforated crumb
tray 19, past the bimetal bar 'i5 and through the
opening or openings 11 in the base plate 2l,
65 vertically upwardly past the toast heating ele
ments and out through the opening is.
.
W e provide further a secondary toast heating
element control switch including a spring bar 8l
connected in series electric circuit with the bimetal
bar l5 and the toast heating elements 23 and 25,
this bar 8| having a contact member 83 at its free
end. A second contact member 85 is mounted on
an auxiliary current traversed bimetal bar 3i
for a purpose which will hereinafter appear. The
free end of the bimetal bar 'l5 is provided with an
5
2,412,727
adjustable short machine screw 3Q which is
adapted to engage a small lug di of electric in
sulating material mounted on spring b r Si near
the contact member t3.
The diagrams oi connection shown
Figs. 5
and 6 disclose the connections oi the toast heating
elements, the bimetal bars
d? and the
auxiliary switch just above described. The design
6
heating elements will be substantially the same
as was supplied to the toast heating elements
when connected to a 105 volt circuit.
If now a
light piece of toast is desired, the timer will be
mandati adjusted by the operator to reduce the
length oi a toasting operation, but the same gen
eral comments made hereinbefore as to dark
toast will apply.
and construction of the bimetal bar
is such
One of the results of our new method of toasting
that when heated it will move in a counter-clock 10 _is that instead of what may be called purely “sur
wise direction as seen in Fig. 2 of the drawings,
face toasting” being effected, a slice of bread is
and will cause set screw
to engage lug @i on the
toasted deeper and the inside of the slice of bread
spring Contact bar Si at a given temperature to
is baked out or dried out to some extent.
thereby cause opening of the heating circuit oi the
Our new method of operation as obtained by
toast heating elements.
It has been found that in a structure of this
general 1sind, contact me i ers S3 an
are
the use of a toaster embodying our invention
results
the intermittent application of toasting
heat, and particularly radiant heat to the sur
faces of a slice of bread, the temperature of this
heat being definitely limited because of the fact
caused to engage each other and to be disengaged
from each other at relati ely very short intervals,
giving rise to radio interference, and we therefore 20 that as soon as this temperature and the tempera
prefer to provide some means for causing a greater
ture of bimetal bar 'i5 reaches a given value, the
difference ci temperature to occur as to bimetal
current is interrupted. As noted above, the past
bar 'i5 before operation ci the secondary switch
method has been to use a variable time or length
is effected. We may use the secondary bimetal
of a toasting period and not to limit the tempera
bar 3l which is so designed and constructed that
ture and our invention provides a new method,
it will move in a clockwise direction, as seen in
namely that of a limited maximum temperature
Fig. 2 of the drawings, when subjected to tempera
and an invariable or fixed length of time of toast
ture rise. The eiîect or result ci” the action of
ing operation irrespective of supply circuit volt
the secondary bimetal bar is to cause disengage
age and the temperature of the toaster structure.
ment of contact members E3 and
to be effected
It may be further pointed out that when a
30
only after an appreciable change oi temperature
toaster of the kind embodying our invention is
of bimetal bar '55 and this change
temperature
used on a relatively low voltage energizing circuit,
can be made to have any desired value.
the length of the current-on periods will be sub
We have found by actual tests on compensated
stantially greater than the length of time of the
toasters of this kind that the operation a toaster
current-off periods but, of course, this condition
embodying our invention results in substantially
will change when the toaster is operated on a cir
the same amount oi" heat energy reaching or
cuit of higher voltage.
aiïecting a slice of bread, for a given setting of the
However, the main distinguishing element of
timing mechanism such as medium, irrespective
our toaster' and its method of operation is that
of the temperature of the toaster because of close- ,I
ly successive toasting operations or because of L., we provide means which will ensure that a sub
stantially presetl amount of heat reaches a slice
connection to different supply circuit voltages.
or slices of bread being toasted irrespective of
The bimetal bar
oí course, effective, since
the temperature of the toaster and particularly
it is traversed by a current either the saine as or
of its toasting chamber and irrespective also of
proportional to that traversing the toast heating
the voltage of the supply circuit to which the
elements, to limit the temperature to which the
toast heating elements may be connected.
surfaces of a slice of bread `eing toasted are sub
Various modifications and changes may be
jected. .t is Íurther evident that the adjustment
made in the structure embodying our invention
and setting or” the control parts must be that‘
and al1 such changes clearly coming Within the
which will give the desired degree oi toasting on
scope of the appended claims are to be considered
the lowest supply circuit voltage which
be
as being covered thereby.
used to energize the toast heating elements an
W e claim as our invention:
that, therefore, a slice of bread toasted i a toaster
l. In an automatic electric toaster adapted for
of the kind embodying our invention will be sub
operation on electric circuits of diiîerent voltages
jected to a longer toastinLT operation period than
and comprising toast heating elements, a main
would otherwise be necessary where individual ad
switch for said heating elements, means to start
justments of the timer might be made to adapt
a toasting operation, a constant speed timer star*
the toaster to say greatly differing’ supply circuit
ed running in response to said starting means to
voltages.
time the toasting period and operative to cause
Thus, if a dark piece of toast is desired on a low
opening of said main switch and terminate a
voltage supply circuit (say 105 volts), 'the setting
toasting
operation after a preset ñXed length of
of the timer will be such as to give a relatively
time, a second switch for controlling the ener
long toasting operation period and the tempera
gization of the toast heating elements during
ture controlled switch will be actuated to subject
operation
of and independently of the timer and
the slice of bread to a predetermined amount of 65
a bimetal bar, of substantially U-shape, located
heat during the toasting operation. If now the
same toaster is connected to a supply circuit of
out of close heat-receiving relation with the toast
heating elements and electrically connected in
much higher voltag» say 120 volts, and the same
series circuit with the toast heating elements and
degree of toasting is desired, the adjustment of the
timer will not be changed. The operation of the 70 adapted to actuate said second switch to cause
continuous application of toasting heat to a slice
temperature controlled switch will be .such that
of bread at the start of a toasting operation until
the successive energization periods of the toast
the bimetal bar has reached a predetermined
heatinc1r elements will be shorter
when they
value and intermittent application of toasting
were connected to the 105 volt circuit and the total
heat
thereafter for recurrent periods determined
amount of watt-seconds supplied to the toast 75 by and
variable with the value of the input volt
2,412,727
7
age, and to cause the total amount of such heat
reaching a slice of bread to be constant irrespec
tive of different energizing voltages applied to
the toast heating elements.
2. In an automatic electric toaster adapted t0
8
prising toast heating elements, means to start a
toasting operation, a main switch for said heat
ing elements, a constant speed timer started run
ning in response to said starting means to time
the toasting period and operative to cause open
ing of said main switch at the end of a toasting
operation after a ñxed length of time, the im
provement comprising means controlling ener
operate on electric circuits or" different voltages
and at different toaster temperatures and com~
prising toast heating elements, means to start a
gization of the heating elements during operation
toasting operation, a main switch for said heating
elements, a constant speed timer started running 10 of and independently of the timer for ensuring
that substantially the same amount of heat from
in response to said starting means to time the
said toast heating elements shall reach a slice
toasting period and operative to cause opening
of bread during said fixed length of time of a
of said main switch and terminate a toasting op
toasting operation irrespective of variations in
eration after a preset nxed length of time and t
a second control `switch for said toast heating ele 15 the temperature of the toaster and in the ener
gizing voltage applied to the toast heating ele
ments during operation of and independently of
ments, said means including a bimetal bar, of
vthe timer, a thermal element out of close thermal
substantially U-shape traversed by the same cur
relation with said toast heating elements, heated
rent carried by the toast heating elements posi
in accordance with the current carried by the
toast heating elements and adapted to actuate 20 tioned out oí close heat receiving relation with
the toast heating elements and a vsecond control
said second control switch-to energizewand de
switch for said toast heating elements actuable by
energize said toast heating elements consecu
said bimetal bar for causing consecutive ener
tively to cause substantially the same amount of
gizaticn and deenergization of the toast heating
heat from the toast heating elements to reach
a slice or” bread being toasted during said preset 25 elements during a toasting operation and to in
crease the total time of energization of the toast
ñxed length of time irrespective of the energizing
heating elements during said ñxed length of time
voltage applied to the toast heating elements.
of a toasting operation with decrease in the volt
3. In an automatic electric toaster adapted to
age applied to the toast heating elements.
operate at different toaster temperatures and on
5. In an automatic electric toaster adapted to
electric circuits of different voltages and compris 30
operate on electric circuits of different voltages
ing toast heating elements. means to start a toast
and comprising toast heating elements, a main
ing operation, a main switch for lsaid heating ele
switch for said heating elements, means to start
ments, a constant speed timer started running
a toasting operation, a constant speed timer
in response to said starting means to time the
toasting period and operative to cause opening of 35 started running in response to said starting means ì
to time the toasting period and operative to cause
said main switch and terminate a toasting oper
opening of said main switch at the end of a toast
ation after a preset ñxed length of time, the im
ing operation after a ñxed length of time and a
provement comprising means for ensuring that
second control switch for controlling the ener
'substantially the same amount of heat from said
toast heating elements shall reach a slice of bread 40 gization of the toast heating elements during
operation of and independently of the timer7 a
during said preset fixed length of time of a toast
bimetal bar, of substantially U-shape, out ci close
ing operation irrespective of variations in the
thermal relation with said toast heating elements
temperature of the toaster and in the energizing
adapted to carry the current ño‘wing through the
voltage applied to the toast heating elements,
said means including a thermaliy-actuable switch te. Le1 toast heating elements and to actuate said second
switch to cause intermittent energization of the
controlling energization of said heating elements
toast heating elements and intermittent applica
during operation of and independently of the
tion of relatively high temperature radiant heat
timer and positioned out of close heat receiving
to a slice of bread being toasted, said thermally
relation with the toast heating elements and
- heated in accordance with the currentl carried by u aotuable control switch being eiîective to limit
the temperature reached by the surface of a slice
the toast heating elements for controlling the en
of bread being toasted and to cause substantially
ergization of the toast heating elements to reduce
the same amount of radiant heat to reach a slice
the total time of energization of the toast heat
of bread being toasted during said fixed length of
ing elements during said preset ñXed length of
time of a toasting operation with increase in the l. time of a toasting operation irrespective of varia
tions in the energizing voltage applied to the toast
voltage applied to the toast heating elements.
4. In an automatic electric toaster adapted to
operate at different toaster temperatures and on
electric circuits Vof different voltages and com
heating elements.
JOHN R. GOMERSALL.
MURRAY IRELAND.
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