JPH048688B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a timer control circuit for a roasting device, which locks a timer for a certain period of time in response to the roasting chamber temperature of the roasting device, and starts the timer operation. This invention relates to a control circuit that controls time.

[Conventional technology]

Generally, when cooking continuously using a roasting device equipped with a timer, even if the same roasting time is set, if the so-called interval time from the first roasting to the next roasting is short, the first roasting Since the residual heat affects the next roasting, the degree of roasting will be different between the first time and the second time onwards.

Therefore, it is necessary to detect the residual heat from the first roasting and shorten the roasting time from the first time to make the roasting uniform.

Then, as described in Japanese Utility Model Publication No. 57-49354, the room temperature inside the roasting chamber is sensed by a temperature sensing element, and the timer is not activated until the room temperature reaches a certain temperature, causing the heater to generate heat. A roasting apparatus is known in which a timer is activated when the indoor temperature reaches a certain temperature, and the roasting time is adjusted according to the amount of residual heat in the roasting chamber.

[Problem that the invention seeks to solve]

However, in roasting equipment with this type of structure, the roasting chamber occupies a considerable amount of space, so the amount of residual heat varies depending on the position where the temperature sensing element is placed, so it is difficult to detect the average amount of residual heat. The problem is that it is difficult to do so.

The present invention was made in view of the above problems, and
The amount of residual heat in the roasting chamber can be accurately detected, and even if the same timer operation time is set, the roasting time is adjusted according to the indoor temperature of the roasting chamber of the roasting device, and the degree of roasting is always uniform. The present invention provides a timer control circuit for a roasting device that can perform the following steps.

[Means for solving problems]

The timer control circuit of the roasting apparatus of the present invention includes a control circuit switch that is closed in conjunction with a timer switch of a timer provided in the roasting apparatus, and a control circuit switch that is provided in the roasting chamber of the roasting apparatus and that closes the timer switch. a heating element that is connected to the timer switch via the control circuit switch and a limiting resistor connected in parallel to the control circuit switch and generates heat when the heater is energized; an output circuit that has a temperature sensing element that is provided near the heating element and is sensitive to temperature changes of the heating element and outputs the temperature change as a voltage change; a switching circuit that opens and closes in accordance with the output of this output circuit; The electromagnet is de-energized by opening and closing of the electromagnet, and controls the start of operation of a timer provided in the roasting apparatus, and also opens the control circuit switch by de-energizing.

[Effect]

In the timer control circuit of the roasting apparatus of the present invention, when the timer switch is closed, the heater is energized and roasting is started. At the same time, the control circuit switch is closed, and when the control circuit switch is closed, the heating element is energized and generates heat, and the output circuit outputs the temperature change of the heating element as a voltage change. is excited, and the timer does not start operating until the temperature in the roasting chamber reaches a constant temperature after the heater starts being energized. and,
When the heater is energized, the temperature inside the roasting chamber rises, and the temperature of the heating element also rises. When the heating element reaches a predetermined temperature, the output circuit outputs the temperature change caused by the temperature sensing element as a voltage change, and the switching The circuit demagnetizes the electromagnet, starts the timer, and opens the control circuit switch. When the control circuit switch is opened, a current sufficient to maintain the temperature of the heating element flows through the limiting resistor. The temperature inside the roasting chamber rises when the heater starts energizing, but since the roasting chamber is not completely sealed from the outside air and the hot air radiates outside, the temperature inside the roasting chamber remains almost constant. Since the temperature will not rise any higher than that, the heating element can be matched to the temperature characteristics of the temperature inside the roasting chamber, allowing accurate control.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, 1 is a roasting device, and this roasting device 1 has a roasting chamber inside and has heaters 2 shown in FIG. In addition to having a freely adjustable door body 3,
It has a timer time setting knob 4, a lift knob 5, and a browning adjustment dial 6, and also includes a timer 7, a timer control device, and an electric circuit inside.

The timer 7 is a mechanical timer that operates with a spring-type clock mechanism, and the timer 7 is provided with a gear 11 and a balance 12 as a clock mechanism.
A timer shaft 13 having a spring (not shown) wound around the center of the timer 7 is rotatably provided, and a rod-shaped timer winding arm 14 is attached at one end to the timer shaft 13. Furthermore, the tip of this timer shaft 13 protrudes from the front of the roasting device 1,
It is connected to the timer time setting knob 4 mentioned above.

The timer control device includes a lifting table 21 provided on one side of the timer 7 so as to be movable up and down, and a cam 22 for browning adjustment located below the lifting table 21.
and a suction plate 23 whose base end is located below the lifting table 21, whose tip is located below the timer 7, and whose base end is pivoted so as to be movable up and down; A timer lock pin 24 is provided so as to be freely movable in and out of the timer 7, a control circuit switch 25 is provided below the timer 7 in parallel with the timer lock pin 24, and the timer lock pin 24 and the control circuit switch 25 are provided. The electromagnet 26 is also provided with an electromagnet 26 arranged in series.

The lifting table 21 is normally urged to the raised position by a spring (not shown), and the lifting knob 5 is attached to the upper part, and the timer hoisting arm 14 is attached to one side on the timer 7 side. An engaging protrusion 27 that engages from above is protruded.

The cam 22 is rotatably supported by a shaft 28, and the browning adjustment dial 6 is attached to the shaft 28, and when the elevator platform 21 is lowered, it comes into contact with the lower end of the elevator platform 21, and the dial 6 is attached to the shaft 28. It is in a positional relationship that locks the descent, and due to its displacement, the lifting platform 21
This is to regulate the range of decline in

Further, the suction plate 23 has a base end bent downward to form a substantially L-shape, and is in a position such that its lower end comes into contact with the base end when the elevating table 21 is lowered, so that the tip is bent upward. It rotates to.

The timer lock pin 24 has a distal end protruding downward from the timer 7 and a proximal end inserted into the timer 7 so that it can move toward and away from the balance 12 by moving forward and backward.

Further, the electromagnet 26 is wired so that it is energized and excited when the control circuit switch 25 is closed.

When the tip of the suction plate 23 rotates upward, the timer lock pin 24 is pressed and advances into the timer 7 to lock the balance wheel 12 and lock the timer 7. At the same time, the control circuit switch 25 is activated. When closed, the electromagnet 26 is energized, and the electromagnet 26 attracts the attraction plate 23 to maintain the locked state of the timer 7 by the timer lock pin 24.

The electric circuit of the roasting apparatus includes the heaters 2 and 3, which are respectively connected to both ends of an AC power source 31 of 100V via a timer switch 32 of the timer 7.
and a timer control circuit that controls when the timer 7 starts operating.

This timer control circuit is formed by sequentially connecting the control circuit switch 25, a DC constant voltage power supply, an output circuit, a switching circuit, and the electromagnet 26.

A high-resistance limiting resistor 33 is connected in parallel to the control circuit switch 25.

The DC constant voltage power supply includes three parallel bleeder resistors 41 and 4 as heating elements connected between the control circuit switch 25 and one end of the AC power supply 31.
2, 43, two capacitors 44, 45, two Zener diodes 46, 47, and a diode 48. The resistance values of the bleeder resistors 41, 42, and 43 are set so that they each generate heat in proportion to the amount of heat generated by the heater 2.

The output circuit consists of two resistors 50 and 51 connected in sequence between the connection point of the two Zener diodes 46 and 47 of the DC constant voltage power supply and the (-) end of the DC constant voltage power supply, and a negative electrode as a temperature sensing element. It consists of a characteristic thermistor 52 and a resistor 53, and the thermistor 52 is placed near the bleeder resistors 41, 42, and 43.

The switching circuit consists of a Schmitt circuit and an NPN transistor 61 connected in sequence to a connection point between a resistor 51 and a thermistor 52 forming an output circuit.
3 and two ICs 64 and 65 as inverters, and a resistor 66.
2 is connected to the connection point between the resistor 51 and the thermistor 52 of the output circuit, and the resistor 66 is connected to the
It is connected to the base of an NPN transistor 61.

The collector of the NPN transistor 61 is connected to the (+) end of the DC constant voltage power supply through a parallel circuit of the electromagnet 26 and the diode 71, and the emitter is connected to the (-) end.

The operation of this embodiment will be explained below.

When roasting bread or the like using the roasting device 1, first, the cam 22 for adjusting the roasting color is set on the roasting color adjustment dial 6.
Rotate to set the degree of baking in advance. This determines the descending width of the lifting platform 21.

Then, when the lifting knob 5 is pressed down and the lifting table 21 is lowered against the biasing force of the spring, the lifting table 21 is lowered until its lower end abuts the cam 22, and at the same time, the engaging protrusion 27 is moved against the timer winding arm 14. is engaged with and rotated downward to wind the mainspring of the timer shaft 13. The timer operating time is determined by the amount of hoisting, but since the cam 22 restricts the descending width of the lifting platform 21, the same timer operating time can always be set if the cam 22 is set at a constant position.

Then, as the mainspring is wound up by the timer winding arm 14, the timer switch 32 is closed, the heater 2 is energized, and roasting is started at time a in FIG. 4 of the table 4. However, the timer lock pin 24 advances into the timer 7 when the lifting table 21 descends and its lower end pushes down the base end of the suction plate 23 and rotates the tip of the suction plate 23 upward. Since the lamp 12 is locked, the timer 7 does not start operating at time a. At the same time, the control circuit switch 25 is closed by the suction plate 23, and the electromagnet 26 is excited to attract the suction plate 23, so the timer lock pin 24 remains pressed against the suction plate 23. The timer 7 is held in a locked state.

That is, when the control circuit switch 25 is closed, the timer control circuit is energized, but at this point a, the inside of the roasting chamber is not yet sufficiently heated by the heater 2, and the temperature is proportional to this. Since the bleeder resistors 41, 42, and 43 do not generate enough heat, the resistance value of the thermistor 52 is large, and the voltage across the thermistor reaches the "H" level and applies the Schmitt circuit, so the output of the Schmitt circuit also becomes "H". H level and turns on the NPN transistor 61. Therefore, the electromagnet 26 is energized and as long as the resistance value of the thermistor 52 is high, it attracts the attraction plate 23 and holds the timer 7 in a locked state.

Then, as the temperature inside the roasting chamber gradually increases and the amount of heat generated by the bleeder resistors 41, 42, and 43 increases accordingly, the resistance value of the thermistor 52 decreases, and after (T ₁ ) time, when the resistance value reaches a predetermined value, b At this time, the voltage across the thermistor 52 goes to the "L" level, and the output side of the Schmitt circuit also goes to the "L" level, so the NPN type transistor 61 is turned off and the excitation of the electromagnet 26 is also released. Therefore, the tip of the suction plate 23 separates from the electromagnet 26 and rotates downward under its own weight to open the control circuit switch 25 and release the lock of the timer 7 by the timer lock pin 24, so that the timer 7 is not activated at time b. is started.

Then, when the timer set time _T2 has elapsed, the operation of the timer 7 ends at time c, and the timer switch 32 is opened, and the first roasting ends. The roasting time T ₃ at this time is the above (T ₁ +T ₂ ).

Note that since the control circuit switch 25 is open during the timer operating time _T2 , if this continues, the bleeder resistors 41, 42, and 43 will start to cool down from point b.
Although there is a possibility that the cooling speed is not proportional to the temperature of the heater 2, which starts to cool down from point c when roasting ends, it is possible to connect the limiting resistor 33 in parallel with the control circuit switch 25, and even if the control circuit switch 25 is open while the timer is operating. Since a minute current was made to flow through the bleeder resistors 41, 42, 43, the bleeder resistors 41, 42, 43
43 does not cool down rapidly, but cools in proportion to the inside of the roasting chamber.

Next, when performing the second roasting after a certain interval time _T4 , roasting will start at time d when the lifting platform 21 is lowered by the same operation as above, but the thermistor 52 will not be activated during the first roasting. The residual heat held by the bleeder resistors 41, 42, and 43 due to roasting has warmed them since the start of the first roasting, so their resistance values reach a predetermined resistance value and the voltage across them becomes " The time T ₅ until it reaches L level is 1
This is shorter than the second time _T1 , and the time e at which the timer 7 is unlocked and the timer 7 starts operating is earlier. Therefore, even if the timer setting time T ₆ from time e to the end of timer operation f is the same as the previous timer setting time T ₂ , the overall roasting time T ₇ is shorter than the first roasting time T ₃ . However, since residual heat from the previous roasting acts on the second roasting, even if the roasting time is short, the amount of heat given to the object to be roasted is the same as that of the previous roasting, and therefore the degree of roasting will be uniform compared to the previous roasting.

In the above embodiment, the heating element uses the bleeder resistors 41, 42, 43 forming a DC constant voltage power supply, so there is no need to increase the number of parts and costs can be reduced.

Note that the negative characteristic thermistor 52 is not provided, and the positive characteristic thermistor is replaced by two Zener diodes 4.
It may be connected between the connection point of resistors 6 and 47 and the connection point of resistors 62 and 53. In this case, since the resistance value of the positive temperature coefficient thermistor is low at low temperature, the voltage across the resistor 53 becomes high; At high temperatures, the resistance value of the PTC thermistor decreases, so the voltage across the resistor 53 decreases. Therefore, the Schmitt circuit and the NPN type transistor circuit 69 operate in the same manner as in the above embodiment to excite or demagnetize the electromagnet 26 and set the timer 7.
Locked or unlocked.

Furthermore, the above Schmitt circuit is formed of ICs 64 and 65 that form an inverter, but the gate
It may also be formed by IC.

Further, in the above embodiment, the timer control circuit is formed to control the timer operation of a mechanical timer, but the timer control circuit of the present invention can be applied to a timer circuit of an electronic timer using a time constant circuit consisting of a resistor and a capacitor. may be connected. In this case, a switch that is opened and closed by the excitation and demagnetization of the electromagnet 26 is connected to the time constant circuit of the electronic timer,
When the temperature in the roasting room reaches a predetermined temperature, this switch is closed to start charging the capacitor of the electronic timer, and when charging is finished, the timer switch of the electronic timer is closed to finish roasting. .

〔Effect of the invention〕

According to the present invention, by controlling the timer operation start time and adjusting the roasting time in accordance with the roasting room temperature, it is possible to always make the degree of roasting uniform when roasting continuously. In the baking equipment,
A heating element that generates heat when the heater is energized by closing the timer switch is connected to a control circuit switch and a limiting resistor that are connected in parallel, and the timer starts operating through an output circuit having the heating element via a switching circuit. Since we installed an electromagnet that controls the time and opens the control circuit switch, current flows to the heating element via the control circuit switch from the time the heater starts energizing until the temperature in the roasting chamber reaches a certain temperature. When the temperature in the roasting chamber reaches a certain temperature, the timer starts operating, and a current flows through the heating element through the limiting resistor to maintain the temperature, and the temperature in the roasting chamber remains constant due to heat dissipation. Since the above temperature does not rise, the heating element can be adapted to the temperature characteristics inside the roasting chamber, and when roasting continuously, the accurate residual heat inside the roasting chamber can be sensed to make the degree of roasting more uniform. be able to.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a roasting device equipped with a timer control circuit according to an embodiment of the present invention, FIG. 2 is a schematic diagram of the timer control device, FIG. 3 is an electric circuit diagram of the roasting device, and FIG. The figure shows the operating characteristics of the device according to the invention. 7...Timer, 25...Control circuit switch, 2
6... Electromagnet, 32... Timer switch, 33...
...Limiting resistance, 41, 42, 43...Bleeder resistance as a heating element, 52...Thermistor as a temperature sensing element.

Claims (1)

[Scope of Claims] 1. A control circuit switch that is closed in conjunction with a timer switch of a timer provided in the roasting device; and a control circuit switch that is provided in the roasting chamber of the roasting device and is energized when the timer switch is closed. a heater; a heating element connected to the timer switch via the control circuit switch and a limiting resistor connected in parallel to the control circuit switch and generating heat when the heater is energized; and a heating element provided near the heating element. an output circuit that has a temperature sensing element that is sensitive to temperature changes in the heating element and outputs the temperature changes as voltage changes; a switching circuit that opens and closes according to the output of this output circuit; and de-excitation by opening and closing of this switching circuit. A timer control circuit for a roasting device, comprising: an electromagnet that controls when a timer provided in the roasting device starts operating, and opens the control circuit switch by degaussing.