U.S. patent application number 09/874812 was filed with the patent office on 2002-01-10 for electric toaster.
Invention is credited to Chan, Stephen Wai-Kin, Li, Wing Chung.
Application Number | 20020002910 09/874812 |
Document ID | / |
Family ID | 9893018 |
Filed Date | 2002-01-10 |
United States Patent
Application |
20020002910 |
Kind Code |
A1 |
Chan, Stephen Wai-Kin ; et
al. |
January 10, 2002 |
Electric toaster
Abstract
In an otherwise well-known electric pop-up toaster, an auxiliary
power switch is provided and is arranged to be opened by a timer
after each toasting cycle. This ensures, in contrast to the
well-known toaster arrangements, that power is interrupted to
heating elements even if a carriage supporting slices of toast
fails to move up at the end of a toasting cycle.
Inventors: |
Chan, Stephen Wai-Kin; (Hong
Kong, HK) ; Li, Wing Chung; (Hong Kong, HK) |
Correspondence
Address: |
JACKSON WALKER L.L.P.
Suite 2100
112 E. Pecan Street
San Antonio
TX
78205
US
|
Family ID: |
9893018 |
Appl. No.: |
09/874812 |
Filed: |
June 5, 2001 |
Current U.S.
Class: |
99/327 ; 99/329P;
99/329RT |
Current CPC
Class: |
A47J 37/0842 20130101;
A47J 37/0814 20130101 |
Class at
Publication: |
99/327 ;
99/329.00P; 99/329.0RT |
International
Class: |
A23L 001/00; A47J
027/62 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 5, 2000 |
GB |
0013672.1 |
Claims
1. An electric pop-up toaster having a timer for timing each
toasting cycle, a spring biassed carriage and a hold-down catch for
retaining the carriage in a lower position for toasting, a power
switch for heater elements of the toaster that is closed by the
carriage whenever the carriage is in its lower position and opens
when the carriage moves away, and an auxiliary power switch that is
opened by the timer after the end of toasting cycles.
2. An electric pop-up toaster according to claim 1, in which the
timer is arranged to open the auxiliary power switch and release
the hold down catch simultaneously.
Description
[0001] The invention relates to electric toasters.
[0002] Electric toasters or so-called "pop-up toasters" are
well-known and typically include timers or other devices to
automatically turn off electrical power to heating elements at the
end of each toasting cycle, At the same time, a spring biassed
bread carriage is released inside the toaster to lift up the toast
and cause the toast to "pop-up" and be removed for use. Commonly
the opening of a switch and the mechanical release of a carriage
hold-down catch are inter-related and so if the carriage jams, the
power may be prevented from being turned OFF. This leads to the
possibility of burning the toast and also creating a
fire-hazard.
[0003] It is an object of the invention to overcome this
problem.
[0004] According to the invention there is provided an electric
pop-up toaster having a timer for timing each toasting cycle, a
spring biassed carriage and a hold-down catch for retaining the
carriage in a lower position for toasting, a power switch for
heater elements of the toaster that is closed by the carriage
whenever the carriage is in its lower position and opens when the
carriage moves away, and an auxiliary power switch that is opened
by the timer after the end of toasting cycles.
[0005] The timer may be arranged to open the auxiliary power switch
and release the hold down catch simultaneously.
[0006] An electric pop-up toaster according to the invention will
now be described by way of example with reference to the
accompanying drawings in which:
[0007] FIG. 1 is an elevation of the toaster;
[0008] FIG. 2 is a schematic circuit diagram for the toaster;
and
[0009] FIG. 3 is a circuit diagram for the toaster.
[0010] Referring to the drawings, in FIG. 1 a housing 10 surrounds
a carriage 11 that is slidably mounted in the housing and biassed
to an upper position, as shown in the Figure, by a spring 12.
Heating elements 13 are provided and supplied with electrical power
for toasting bread as required. A manually grippable handle 14 is
coupled to the carriage 11 for moving the carriage down to a lower
position A printed circuit board 15 is mounted in the housing and a
timer 16 is mounted to the board 15. A carriage hold-down catch
consists of a pair of conductors 17 and a latching plate 18 that
closes across the conductors when the carriage is in its lower
position The latching plate 18 is held against the plate as long as
current is supplied to a coil 19 surrounding a ferro-magnetic core
20 A main power switch 21 for both the heating elements 13 and
powering the printed circuit board 15 is closed by moving the
carriage 11 to its lower position.
[0011] The toaster so far described is in wide commercial use
already. In use of the known toasters, bread slices are placed in
the toaster on top of the carriage 11 and the handle 14 is pressed
down to move the carriage and the bread slices down the lower
position. The power switch 21 is turned ON and the timer begins a
pre-set (manually adjustable) timing period to toast the bread
slices. Closure of the power switch 21 causes current to flow in
the coil 19 so that the latch 18 is held against the conductors 17.
This holds the carriage in its lower position against the bias of
the spring 12. At the end of a toasting cycle, the timer turns off
the current in the coil so that the latch 18 (the so-called
"hold-down catch") is released and the carriage moves up to allow
the power switch 21 to OPEN when the toast "pops-up". Current to
the heating elements is therefore cut-off.
[0012] A problem and the possibility of a fire hazard arise if,
when the latch 18 is released, the carriage fails to move up under
the bias of the spring 12. (This may arise due to the carriage
jamming or being held down by toasted bread on the carriage.) If
this happens, the power switch 21 does not OPEN and the heating
element continues to be supplied with power.
[0013] To overcome this problem, embodiments of the invention are
provided with an auxiliary power switch 22 shown in FIG. 2. The
auxiliary switch 22 is closed by a driving circuit 23 while the
power switch 21 is turned on. The timer 16 is arranged at the end
of each toasting cycle to release the auxiliary switch 22 by
disenabling the driving circuit 23. As in conventional toasters,
the discontinuity of current to the coil 19 opens the main power
switch 21. That means not only is the latch 16 released but also
power to the heating elements 11 is interrupted by opening of the
auxiliary switch 22. Thus, although the power switch 21 may remain
CLOSED, because the carriage has not moved upwards, no further
heating of the toast will occur.
[0014] The circuit can be reset by turning off power of the toaster
or forcing the handle 14 upwards to allow the power switch 21 to
open. In a normal operation of the toaster, that is when the
carriage moves up normally at the end of a toasting cycle and the
main power switch 21 has opened, the auxiliary switch 22 opens at
the same time.
[0015] FIG. 3 shows the circuit components of the toaster.
* * * * *