Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention provides an automatlc steam cooker in which one of the eggs
to be cooked is placed in a holder which is suspended by torsion springs
thus forming a rotational inertia-spring system. The automatic mechanism
continuously applies initial rotational displacement to this system and
then measures and integrates the amplitude of oscillations. The total
amplitude of oscillatlons i5 an indication of the conslstency of the
egg. The firmer the egg, the larger the amplitude of oscillations.
This is due to the char,ge of the damping ratio of the system. When the
total amplitude reaches a pre-set amount, the cooker rings a bell or a
buzzer.
In the present art of automatic egg cookers, the cookers do not sense the
conslstency of the eggs, but either ring a bell or remove the eggs from
bolllng water after a pre-set time. Thls is not satisfactory since the
time an egg cooks depends on many factors, such as the amount of heat
applied, how cold the egg was at the start, how old the egg is and its
slze.
It is the obJect of my invention to provide an egg cooker whlch senses the
conslstency of the egg inslde without breaking it open and whlch rings an
alarm when the egg reaches a preselected conslstency. Another ob~ect of
mv invention i5 to provlde an egg cooker which is self-contained and
provides all the power required for the device from the steam generated
in the cooker. Another obJect of my lnvention is to provide an egg cooker
in which the testlng and sensing of the egg conslstency is done auto-
matically. ~hese and other ob~ect~ of my in~ention will become apparent
in the description and drawings which follow.
In drawings which illustrate embodiments of my lnvention,
Flgure 1 iB a cross-sectional view of the cooker, the egg belng tested
ln the holder and the other eggs;
Flgure 2 shows the mRchanlsm by whlch the egg is tested, the steam turbine
3 and the clockwork which operates the system;
Figure 3 shows the detalls of the steam turblne;
Figure 4 shows varlous key components in pictorial form;
Figure 5 shows the solenoid and magnet arrangement as used in the electro-
nically controlled cooker;
Figure 6 shows the circuit in block diagram form of the electronlcally
controlled cooker;
Flgure 7 shows another arrangement of the system of Fig. 6 in which the
number of oscillatlons is counted.
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In Figure 1, 1 ls the container pot shown in segmented pictorial view.
2 is one of the eggC which is placed in egg holder 3; 4 is an egg holder
support which supports the egg holder at the lower end via torsional spring
wire 5. The upper end of the holder i~ supported on lid 6 via torsional
spring wire 7 and bracket 8 (See also Figure ~ racket 8 is fixed to the
lid. 9 are the other eggs in the cooker which are placed in a tray with
holes in it. A tube 10 is attached to the upper end of egg holder 3 and
surrounds wlre 7. Wire 7 passes through tube 10 and is al90 attached to
the upper part of egg holder 3 at the bottom of tube 10. Tube 10 passes
through the lid vla a hole 11 whlch ls sllghtly larger than the outside
diameter of tube 10 and thus tube 10 does not touch the lid. Member 12
is provlded wlth a hole at one side and is press fitted over tube 10. Flat
~pring members 13 are also attached to member 12 at a point near tube 10.
Springs 13 are both bent to one side and they exert a force on toothed
wheel 14 and thus form a ratchet arrangement so that when the egg holder
oscillates, toothed wheel 14 rotates. Wheel 14 has a sleeve bearlng 15
which i8 flxed to it. A flexible strlng 16 is attached at one end near
the centre of wheel 14 and at the other end to one end of flat sprlng
element 17. ~he other end of sprlng 17 ls flxed to the lid. When wheel 14
rotates, strlng 16 winds on bearing 15. ~earing 15 is rotatably supported
by pln 18 whlch 19 fixed to the lld by pln holder 19. Holder 19 also holds
controlllng lever 20 onto the lld, but allows it to rotate. Sprlng washer
21 provldes frictlon for the ad~usting lever. The rest of the mechanism
consists of a clockwork comprising gears 22, 23, 24 and 25, the steam
turbine C, a reset sub-a~sembly A, a bell hammer sub-assembly ~ and a
bell 29.
Construction of the turblne sub-a~3embly C is shown ln Figure 3. It con-
slsts of an upper hollow rotating member 30 to which two plpes 31 are
attached. Plpes 31 are bent by ~0 degrees at their outer ends to form
3 Jet~ whlch provlde the torque. Sleeve bearlng 32 i8 press fitted into a
hole at the top of member 30 and 1B free to rotate on shaft 33. Shaft
33 is fixed to the lower and stationary part of turblne member 34. Sleeve
bearlng 32 also supports spur Bear 26 at the top of the turblne. ~ember
34 is press fitted onto the lld and has holes underneath for the steam to
go through. Turbine C provid~s power to the system via ~ear train 25,
24, 23 and 22. Gear 22 18 provlded with a peg 35. Peg 35 i8 arranged to
come ln contact wlth member 12 and sub-assemblles B and A.
Sub-assembly B conslsts of a plvoted cyllndrical member 36. Rigid wire 37
protrudes from the slde of member 36. Semi-rlgid wire 38 is also attached
4 to member 36 and at its end a welght 39 is attached to form the ha~mer
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for ringing bell 29. Two flat sprlng members are alæo attached to member 36,
one spring 40 is a stiff spring and the other spring 41 i9 a weaker spring.
Spring 41 rests on peg 42 which is fixed to the lid. Spring 41 tends
to rotate the whole sub-assembly B counterclockwise. This causes wire 38
to press against peg 43. In this posltion hammer 39 is near bell 29 but
does not touch it.
Sub-assembly A consists of pi~oted cylindrical member 44 on which
rigid wires 45 and 46 are attached at opposite sides. Wire 46 is bent
upwards at its free end. The purpose of this assembly is to llft sprlng~ 13
off wheel 14 and reset the measuring mechanism when peg 35 on wheel 22
pushes against wire 45.
Operatlon of the egg cooker is as follows: One of the eggs to be cooked
is placed on the egg holder~ the pot is filled with a small quantity
of water and the lid 18 placed on the pot. The lld fits tightly on the
pot so that a small amount of steam pressure develops when the water boils.
The steam passes through the holes of member 34 of the turblne and through
turbine tubes 31, thus settlng the turblne ln rotation which, ln turn,
rotates the rest of the gears. This starts a cycle of vibratlng the egg
holder and egg~ measurlng the total amplitude of all oscillatlons~ rlnging
the bell when the sum of all amplltudes reaches a predetermined polnt
and resettlng the mechanlsm.
This is done as follows: Peg 35 on gear 22 pushes member 12 to one side~
causing it to rotate partly in the clockwise directlon (See Flg. 2).
After peg 35 rotated beyond the reach of me~ber 12, member 12 is released
and the egg holder 3 and egg 2 i8 set ln osclllatory rotatlonal motion
due to the moment of lnertia of the egg and the torslon provlded by
9prlng wires 5 and 7. While the egg holder, egg and member 12 are
oscillating, flat springs 13 push alternately on toothed wheel 14 which,
due to the ratchet effect, rotate~ in a clockwise directlon. The total
amount of rotation of wheel 14 18 proportional to the sum of all the
peak amplitudes of all the osc111atlons. If the egg is raw and in liquid
form~ the osclllatory system ls heavily d~mped, the osclllation~ die down
fast snd the rotstlon of wheel 14 18 smsll. If, however, the conslstency
of the egg i9 firm~ the system ls less damped, the oscillations last
longer and wheel 14 will turn farther. Next, peg 35 pushes on wire 37
; and causes sub-assembly B to rotate sllghtly clockwise. When peg 35
rotates beyond the reach of wire 37, sub-assembly B 18 released and,
due to spring action of sprlng 41 pressing against peg 42, sub-assembly B
; will return to its origlnal positlon and wire 3B will rest on peg 43;
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but, because spring 41 is a weak spring, hammer ~9 will not ring the bell.
If, however, wheel 14, due to larger oscillations of the egg, rotated to
the point where protrusion 48 on wheel 14 came to rest under spring 40,
then, when sub-assembly B is released, it will return to its orlginal
position with greater velocity. In this case, because of flexure of
wire 38, the hammer will hit the bell. Next, peg 35 pushes against wire
45 and causes sub-assembly A to rotate slightly clockwise. This causes
wire 46 to push springs 13 away from wheel 14. When this happens, wheel
14 will turn counterclockwise due to the action of spring 17 and string 16.
While wheel 14 was turning clockwise~ string 16 was winding on sleeve 15
ABainst the force provided by spring 17. Wheel 14 will keep turning
counterclockwise until protruding member 47 comes to rest on the vertical
part of controlling lever 20. The amount of rotation of wheel 14 required
to cause the bell to ring depends on the position of controlling lever 20.
If lever 20 i8 set in a more counterclockwise position, wheel 14 will
have to rotate farther before the bell rings. For this to happenJ the
consistency of the eg~ must be firmer. The opposite will happen if
lever 20 is set ln a more clockwise position. Thus the position of
lever 20 determines how firm the egg has to be before the bell will
ring.
Although in the above described device the oscillation, measurement
and reset cyclic proceæs was achieved by the clockwork mechanlsm driven
by a steam turbine, the s~me process can be achleved by havlng the clock
work driven by a malnsprlng, electrlc motor or an~ other source of
mechanlcal power.
In another version of the device, the egg osclllation, measurement and
reset cycle is done electronically (See Figs. 5 and 6). In this case,
member 12 ha8 a magnet 50 attached to it which is curved and fits lnto
a curved solenold 51 whlch ls flxed to the lld. The radius of curvature
of magnet 50 and solenold 51 ls equal to the distance from the point
of attachment o~ magnet 50 to the centre of rotatlon of member 12.
Member 12 and magnet 50 are free to osclllate because m~gnet 50 does
not touch the lnslde surface of solenold 51.
In Flgure 6, block 52 repre~ents tlming circuits which apply pulse
voltages of various duration flrst to transistor 53, then to *ield
effect translstor 54 and then to field ef~ect transistor 55. Thi6
process repeats cycllcally. When a short flrst pulse i8 applied to
the base of translstor 53 momentarlly, capacitor 56, which is
orlginally charged vla resl6tor 57, discharge~ through solenoid 51,
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thus providin~ an impulse torque to the egg, holder and torsion wire
system as before. The system oscillates and magnet 50 induces an AC
voltage in solenoid 51. I~mediately after the first pulse elapsed, a
second pulse of much longer duration is applied to the gate of transistor
54 via resistor 64. This pulse turns transistor 54 on and connects solenoid
51 to amplifier 58. Amplifier 58 amplifies the alternating voltage pro~uced
by solenoid 51. The output voltage from amplifier 58 is full-wave rectified
by bridge rectifier 59 and is applied to integrating smplifier 60. The
output of integrator 60 is a voltage of which the magnitude is proportionsl
to the area under the curve of the waveform produced by rectifier 59.
Therefore, this voltage is proportional to the total sum of all the
oscillations produced by the egg, holder and ~pring system. Control poten-
tiometer 61 divides down the output voltage from integrator 60 and applies
it to the base of transistor 62, thus providing base current. Transistor 62
drlves alarm unlt 63 which sounds an alarm when the base current in tran-
sistor 62 reaches a certain level.
In operatlon, control 61 is set for the desired consistency of the eggs
belng cooked. If control 61 ls set with the wiper near the ground connection,
a higher voltage will be required out of integrating amplifier 60 to provide
sufficlent base current to transistor 62 to operate the alarm. This con-
ditlon will occur when the egg is quite firm in consistency. If the wiper
of control 61 is set to the other end of the potentiometer, a softer egg
will cause the alarm to ring. This last version of the egg cooker 18
particularly suited for incorporatlon into an electrlc cooker whlch i8
electrlcally heated by sn element at the bottom of the pot.
Another method of testing the egg for conslstency is to place it in an
oscillatory system and set it oscillatlng, as before, and count the number
o~ oscillatlon~ exceeding a pre-set amplltude. Thls can be achieved by
slight modificatlon to the sy~tem shown ln Fig. 6. Flg. 7 shows the
3 modifled clrcult. The output of rectlfler 59 ls applled to amplifier 70. Ihe ampllfied full-wave rectlfled signal is applled to potentiometer 71
which sets a threshold. The divlded down slgnal from potentlometer 71 is
fed to Schmitt trlgger 72 whlch converts the signal ~nto pulses. These
pulses are fed to counter 73 where they are counted. The number registered
in counter 73 is dRcoded by decoder 74 which is set to provide a voltage
to transistor 62 when a certain number in counter 73 is decoded, and ~his
rings alarm 63~ Counter 73 1~ reset by the timing clrcuits of block 52 at
the end of each cycle of operatlon. In thls system, the alarm is set to
rlng at the deslred consistency either by ad~usting threshold potentiometer
4 71 or by setting decoder 74 to activate the alarm clrcuits when a
certain number is registered in the counter. Setting the wiper of poten-
i74
tiometer 71 near the ground connection will require the oscillationsof the egg to keep greater amplitude~ for longer time in order for the
alarm to sound. This means that the egg has to be firmer. The same can
be achieved by setting decoder 74 to produce an output to transistor 62
when a greater number of counts is regictered in counter 7~.
It is possible to cook poached eggs in the egg cooker by providing small
trays in which the contents of the eggs can be placed. The trays can be
put in the egg cooker in place of the whole eggs. One tray is placed in
the egg holder. By providing these trays, the egg cooker becomes more
versatile.
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