JPS604881A - Timing correcting apparatus - Google Patents

Abstract

PURPOSE:To make it possible to toast bread so as to always obtain a constant toasted color by enabling the correction of a current supply time to load, by closing a switch for connecting a power source and load while controlling a time before starting the driving of a motor timer. CONSTITUTION:A switch 12 and load 13 are connected to a power source 11 in series while a delay element 14 starting charging by closing the switch 12 and starting discharge in predetermined time constant by opening said switch 12, a comparator 15 for judging that the charge level of the element 14 reaches a predetermined value, a switching element 16 triggered by the comparison output of said comparator 15 and a motor timer 17 for opening the switch 12 after a predetermined time is elapsed are mounted. After the switch 12 is closed, a time before the driving of the timer 17 is started is controlled by the delay element 14 and the comparator 15 to correct a current supply time to the load 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is for controlling overcurrent in electrical appliances such as toaster ovens.

Conventional structure and its problems Traditionally, for example, when toasting is performed in a toaster oven, especially when toasting is performed continuously, the operating time of the timer that controls the energization of the heating element is not constant. If there is, there will be a difference in the browning color of the toast between the first time without preheating and the second time with preheating. In order to prevent this, the setting time of the timer must be changed each time depending on the preheating state of the vessel, which is extremely troublesome.

As a solution to this problem, as shown in the block diagram of FIG. 1, a heat generating bimetal 3 and a heat generating element 4 are connected to the power source 1 via a timer 2, and the bimetal 3 generates heat and is displaced by a predetermined amount. (Yes, there is a time limit correction device that has a stop-drive mechanism 5 that releases the stop state of the time limit device 2.

However, since this conventional time correction device uses the displacement due to heat generation of the bimetal 3 for time correction, it is easily affected by the ambient temperature, and the heat generation displacement characteristics of the bimetal 30 are It is extremely difficult to match the cold properties well. Furthermore,
The stop-drive mechanism 5 usually has many sliding parts, and the operation of the timer 2 must be controlled in response to a small displacement force of the bimetal 3. Therefore, if the movement of the sliding part deteriorates, it will stop. - The drive mechanism 5 did not operate well, so it was not possible to perform the prescribed time correction, and its reliability was extremely poor.

OBJECTS OF THE INVENTION It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art and to provide a highly reliable timer that can, for example, always roast toast with a constant browning color.

Structure of the Invention In order to achieve the above object, the timer of the present invention connects a switch 12 and a load 13 in series to a power source 11, as shown in the block diagram of FIG. A delay element 14 that starts charging and starts discharging at a predetermined time constant, a comparator 15 that determines that the charge level of this delay element 14 has reached a predetermined value, and this comparison. It consists of a switching element 16 that is triggered by the output of the switch 16, and a motor timer 17 that is driven by this switching element 16 and opens the switch 12 after a predetermined period of time has elapsed.
The delay element 14 determines the time until the motor timer 17 starts driving.
By controlling the comparator 15, the energization time to the load 13 is corrected.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 3, reference numeral 11 denotes a power source, to which a switch 12 and a load 13, which is a heating element such as an electric heater, are connected in series.

Reference numeral 14 denotes a delay element (hereinafter referred to as a capacitor) connected in series to the charging resistor 18, which is charged by the current flowing through the charging resistor 18, and the voltage V of the capacitor 14 is increased.
c rises. 19 is a discharge resistor, one end of which is connected to comparator 1.
5 (hereinafter referred to as PUT), and the other end is connected to the terminal of the capacitor 14.The discharge time constant determined by the discharge resistor 19 and the capacitor 14 is determined by the It is specified to match the cold characteristics.

In addition, a voltage G determined by approximately the division ratio of the series resistor connected in parallel to the constant voltage diode 20 is applied to the gate terminal of the PUT 15 when the PUT 6 is non-conductive, and this gate voltage G is applied to the charging resistor. 18 and capacitor 14
It is set to correspond to the VC which increases with a charging time constant determined by , and to match the heating characteristics of the vessel heating chamber.

16 is a switching element (hereinafter referred to as a strike), 1
Reference numeral 7 denotes a motor timer whose time limit is set by rotating an operating shaft (not shown), and a triac 16 and a motor timer 17 connected in series are connected to a power source 11 via a switch 12. The motor timer 1a is configured to close the switch 12 when a time limit is set, and open the switch 12 after the set time has elapsed.

21 and 22 output a signal to the gate of the triac 16 according to the state of vG at the gate of PUTl 5;
These are first and second transistors that control conduction of the triac 16.

The operation of the above configuration will be explained with reference to FIGS. 3 and 4.

Rotate the operating shaft of the 11th toast roasting motor timer 17 to set a predetermined time limit (
At time 12), switch 12 closes and load 13
When energization starts, a charging current flows into the capacitor 14 through the charging resistor 18, and the voltage VC gradually increases with a time constant determined by the resistance value of the charging resistor 18 and the capacitance value of the capacitor 14. PUTl5 is in a non-conducting state until the voltage exceeds vG, and during this time, the first transistor 21 is in the ON state and the second transistor 22 is in the OFF state, so no current flows through the gate of the track AC 16. The triac 16 is in a non-conductive state, and the motor timer 17 is not driven and stopped. After the predetermined time t1 has elapsed, ■c exceeds vG and PUTl
When 5 becomes conductive, the potential of vG becomes almost O,
The first transistor 21 is OFF, the second transistor 22
turns on, current flows to the gate of the triac 16, the triac 16 becomes conductive, and the motor timer 1
7 is driven.

While the motor timer 17 is driving, PUTlts maintains a conductive state, and c changes to stabilize at a voltage determined by the division ratio of the resistance values of the charging resistor 18 and the discharging resistor 19.

When the time limit setting time t2 of the motor timer 17 has elapsed, the switch 12 is opened and the power supply to the load 13 is stopped.

(Time for energizing the load T1 = 11 + t2) 2 Rest period This rest period (time Ts) starts from the end of the first roasting.
This is the so-called interval time before the start of the first roasting, during which the charge stored in the capacitor 14 at the end of the first roasting is discharged through the discharge resistor 19 and the PUT 16, and the discharge characteristics are as described above. Compatible with the cooling characteristics of the heating chamber.

When the operating shaft of the motor timer 17 is rotated again for the 22nd toast roasting and the time limit is set to the same time t2 as the first time, the switch 12 is closed and the load 13 is started to be energized again. When the switch 12 is closed, the gate terminal of the PUT 15 has a constant voltage VG.
is applied, and the potential of this vG begins to drop to a potential corresponding to the rest time Ts due to the discharge of the capacitor 14 during the rest period. Since it becomes higher than c, the PUT 15 becomes non-conductive9, and the capacitor 14 becomes Switching from the discharging state to the charging state, the potential ■c rises again, and after a predetermined time t1' has elapsed, it exceeds vG and PUTles becomes conductive. Thereafter, the same operation as the first toast roasting is performed.

Here, the energization time T2 to the load 13 is T2=t11+t2
As mentioned above, since the charging start potential of the capacitor νZ4 starts from the potential corresponding to the pause time Ts,
Since the time t1' until the motor timer 17 is driven becomes shorter than the same time t1 during the first toast roasting, the energization time to the load 13 is corrected and shortened, resulting in the same toast color as the first toast. Toast roasting is possible.

Effects of the Invention As is clear from the above embodiments, the time correction device of the present invention adjusts the charging resistance and the discharging resistance to match each of the heating and cooling characteristics of the heating chamber of a toaster oven or the like. Since it is possible to determine independently,
Since the time correction can be performed with high accuracy, the browning color can be kept constant even when toast etc. are continuously roasted.Also, since the drive of the timer is controlled by the charging and discharging characteristics of the delay element, compared to conventional methods. It has great industrial value, such as improved reliability.

Although a toaster oven is described in the embodiments, the present invention can be applied to power supply control of other electrical devices.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional time correction device. FIG. 2 is a block diagram showing a time correction device of the present invention. FIG. 3 is an electric circuit diagram showing an embodiment of the present invention. Voltage-time characteristic diagram of capacitor in circuit diagram 7'Chisa. 11...Power supply, 12...Switch, 1
3...Load, 14...Delay element, 16
......Comparator, 16...Switching element, 17...Motor timer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4, Elapsed time -

Claims (1)

[Claims] A load and a switch connected in series with a power supply, a delay element that starts charging when the switch is closed, and starts discharging with a predetermined time constant when the switch is opened, and a delay element and a charge level that are set to a predetermined value. A timer comprising: a comparator that determines whether the current state has reached 0, a switching element that is triggered by the output signal of the comparator, and a motor timer that is driven by the switching element and opens the switch after a predetermined period of time has elapsed. correction device.