Automatic egg cooker

This invention features an automatic egg cooker in which one of the eggs to be cooked is continuously tested for consistency by being placed in an oscillatory system. The magnitude and duration of oscillations due to an initial displacement of the system are measured. An alarm is set to ring when the desired consistency of the egg is reached.

This invention provides an automatic 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 oscillations is an indication of the consistency of the egg. 
The firmer the egg, the larger the amplitude of oscillations. This is due 
to the change 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 
consistency of the eggs, but either ring a bell or remove the eggs from 
boiling water after a pre-set time. This 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 
size. 
It is the object of my invention to provide an egg cooker which senses the 
consistency of the egg inside without breaking it open and which rings an 
alarm when the egg reaches a preselected consistency. Another object of my 
invention is to provide 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 invention is to provide an egg cooker in 
which the testing and sensing of the egg consistency is done 
automatically. These and other objects of my invention will become 
apparent in the description and drawings which follow.

In FIG. 1, 1 is the container pot shown in segmented pictorial view. 2 is 
one of the eggs 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 is supported on lid 6 via 
torsional spring wire 7 and bracket 8 (See also FIG. 4). Bracket 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 wire 7. Wire 7 passes through tube 10 and is also 
attached to the upper part of egg holder 3 at the bottom of tube 10. Tube 
10 passes through the lid via a hole 11 which is slightly larger than the 
outside diameter of tube 10 and thus tube 10 does not touch the lid. 
Member 12 is provided with a hole at one side and is press fitted over 
tube 10. Flat spring 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 
bearing 15 which is fixed to it. A flexible string 16 is attached at one 
end near the centre of wheel 14 and at the other end to one end of flat 
spring element 17. The other end of spring 17 is fixed to the lid. When 
wheel 14 rotates, string 16 winds on bearing 15. Bearing 15 is rotatably 
supported by pin 18 which is fixed to the lid by pin holder 19. Holder 19 
also holds controlling lever 20 onto the lid, but allows it to rotate. 
Spring washer 21 provides friction for the adjusting lever. The rest of 
the mechanism consists of a clockwork comprising gears 22, 23, 24 and 25, 
the steam turbine C, a reset sub-assembly A, a bell hammer sub-assembly B 
and a bell 29. 
Construction of the turbine sub-assembly C is shown in FIG. 3. It consists 
of an upper hollow rotating member 30 to which two pipes 31 are attached. 
Pipes 31 are bent by 90 degrees at their outer ends to form jets which 
provide the torque. Sleeve bearing 32 is press fitted into a hole at the 
top of member 30 and is free to rotate on shaft 33. Shaft 33 is fixed to 
the lower and stationary part of turbine member 34. Sleeve bearing 32 also 
supports spur gear 26 at the top of the turbine. Member 34 is press fitted 
onto the lid and has holes underneath for the steam to go through. Turbine 
C provides power to the system via gear train 25, 24, 23 and 22. Gear 22 
is provided with a peg 35. Peg 35 is arranged to come in contact with 
member 12 and sub-assemblies B and A. 
Sub-assembly B consists of a pivoted cylindrical member 36. Rigid wire 37 
protrudes from the side of member 36. Semi-rigid wire 38 is also attached 
to member 36 and at its end a weight 39 is attached to form the hammer for 
ringing bell 29. Two flat spring members are also attached to member 36, 
one spring 40 is a stiff spring and the other spring 41 is 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 position hammer 39 is near bell 
29 but does not touch it. 
Sub-assembly A consists of pivoted 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 lift springs 13 off wheel 
14 and reset the measuring mechanism when peg 35 on wheel 22 pushes 
against wire 45. 
Operation 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 is placed on the pot. The lid 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 turbine and through turbine 
tubes 31, thus setting the turbine in rotation which, in turn, rotates the 
rest of the gears. This starts a cycle of vibrating the egg holder and 
egg, measuring the total amplitude of all oscillations, ringing the bell 
when the sum of all amplitudes reaches a predetermined point and resetting 
the mechanism. 
This is done as follows: Peg 35 on gear 22 pushes member 12 to one side, 
causing it to rotate partly in the clockwise direction (See FIG. 2). After 
peg 35 rotated beyond the reach of member 12, member 12 is released and 
the egg holder 3 and egg 2 is set in oscillatory rotational motion due to 
the moment of inertia of the egg and the torsion provided by spring 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, rotates in a clockwise direction. The total amount of rotation of 
wheel 14 is proportional to the sum of all the peak amplitudes of all the 
oscillations. If the egg is raw and in liquid form, the oscillatory system 
is heavily damped, the oscillations die down fast and the rotation of 
wheel 14 is small. If, however, the consistency of the egg is firm, the 
system is 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 slightly clockwise. When peg 35 rotates beyond the reach of wire 
37, sub-assembly B is released and, due to spring action of spring 41 
pressing against peg 42, sub-assembly B will return to its original 
position and wire 38 will rest on peg 43; but, because spring 41 is a weak 
spring, hammer 39 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 original 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 against 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 is set in a more 
counterclockwise position, wheel 14 will have to rotate farther before the 
bell rings. For this to happen, the consistency of the egg must be firmer. 
The opposite will happen if lever 20 is set in 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 process was achieved by the clockwork mechanism driven by a 
steam turbine, the same process can be achieved by having the clockwork 
driven by a mainspring, electric motor or any other source of mechanical 
power. 
In another version of the device, the egg oscillation, measurement and 
reset cycle is done electronically (See FIGS. 5 and 6). In this case, 
member 12 has a magnet 50 attached to it which is curved and fits into a 
curved solenoid 51 which is fixed to the lid. The radius of curvature of 
magnet 50 and solenoid 51 is equal to the distance from the point of 
attachment of magnet 50 to the centre of rotation of member 12. Member 12 
and magnet 50 are free to oscillate because magnet 50 does not touch the 
inside surface of solenoid 51. 
In FIG. 6, block 52 represents timing circuits which apply pulse voltages 
of various duration first to transistor 53, then to field effect 
transistor 54 and then to field effect transistor 55. This process repeats 
cyclically. When a short first pulse is applied to the base of transistor 
53 momentarily, capacitor 56, which is originally charged via resistor 57, 
discharges through solenoid 51, thus providing an impulse torque to the 
egg, holder and torsion wire system as before. The system oscillates and 
magnet 50 induces an AC voltage is solenoid 51. Immediately 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 produced by solenoid 51. The output voltage from 
amplifier 58 is full-wave rectified by bridge rectifier 59 and is applied 
to integrating amplifier 60. The output of integrator 60 is a voltage of 
which the magnitude is proportional 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 
spring system. Control potentiometer 61 divides down the output voltage 
from integrator 60 and applies it to the base of transistor 62, thus 
providing base current. Transistor 62 drives alarm unit 63 which sounds an 
alarm when the base current in transistor 62 reaches a certain level. 
In operation, control 61 is set for the desired consistency of the eggs 
being cooked. If control 61 is set with the wiper near the ground 
connection, a higher voltage will be required out of integrating amplifier 
60 to provide sufficient base current to transistor 62 to operate the 
alarm. This condition 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 is particularly suited for incorporation into an 
electric cooker which is electrically heated by an element at the bottom 
of the pot. 
Another method of testing the egg for consistency is to place it in an 
oscillatory system and set it oscillating, as before, and count the number 
of oscillations exceeding a pre-set amplitude. This can be achieved by 
slight modification to the system shown in FIG. 6. FIG. 7 shows the 
modified circuit. The output of rectifier 59 is applied to amplifier 70. 
The amplified full-wave rectified signal is applied to potentiometer 71 
which sets a threshold. The divided down signal from potentiometer 71 is 
fed to Schmitt trigger 72 which converts the signal into pulses. These 
pulses are fed to counter 73 where they are counted. The number registered 
in counter 73 is decoded by decoder 74 which is set to provide a voltage 
to transistor 62 when a certain number in counter 73 is decoded, and this 
rings alarm 63. Counter 73 is reset by the timing circuits of block 52 at 
the end of each cycle of operation. In this system, the alarm is set to 
ring at the desired consistency either by adjusting threshold 
potentiometer 71 or by setting decoder 74 to activate the alarm circuits 
when a certain number is registered in the counter. Setting the wiper of 
potentiometer 71 near the ground connection will require the oscillations 
of the egg to keep greater amplitudes 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 registered in counter 73. 
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.