JPS6091526A - Time switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a time switch used for setting heating time of a high frequency heating device.

Conventional Structure and Problems The conventional time switch shown in FIG. 1 and the apparatus shown in FIGS. 2 and 3 incorporating this time switch have the following problems.

FIG. 1 is a side view showing the appearance of a conventional time switch. In FIG. 1, a motor 2 is attached to a case 1. The rotation by the motor 2 is transmitted to the shaft 3 via a reducer.
A cam connected to the terminal 4 is rotated, and the contact connected to the terminal 4 is opened and closed by this cam. The coil of the motor 2 is connected to a power source through a lead wire 6 drawn directly from the motor 2.

FIG. 2 is a perspective view showing the appearance of a high-frequency heating device, which is an example of a device incorporating a time switch.

The heating chamber 6 is provided with a door 7 that can be opened and closed.

The heating chamber 6 is irradiated with radio waves from a magnetron (not shown). A time switch knob 9 and a heating start switch button 1° are arranged on the operation panel 8.

FIG. 3 is a circuit diagram of the high frequency heating device.

In FIG. 3, the power source is the heating start switch 11. Time switch contact 12. It is connected to the transformer 16 via a door switch 13, 14 which moves to open and close the door 7. 16
is the time switch motor coil. transformer 15
The secondary coil of the capacitor 17. It is connected to a magnetron 19 via a diode 18.

According to such a conventional time switch, the lead wire 5
Because it is pulled out directly from the motor 2, there is a risk of tensile force being applied to the lead wire during handling, which may cause wire breakage. It is not desirable that many types of time switches are required when the lengths are different.

Furthermore, in a device incorporating such a conventional time switch, if a lightning strike occurs on an outdoor power line, a high voltage pulse will be applied to the device through the power line as so-called induced lightning. For these high voltage pulses, the transformer 16 and motor coil 16 have high impedance,
Discharge occurs between the sunrise wires of the motor coil 16 or between the ground. Since the motor coil 16 is generally made of copper wire, which is much thicker than the windings of the transformer 16, the motor coil 16 may be destroyed by the above discharge. However, if the motor coil 16 is disconnected, the motor 2 will no longer rotate, and the time switch contact 12 will remain "closed" even after the set time has elapsed. As a result, the magnetron 19 continues to oscillate indefinitely, leading to overheating of the object to be heated and even ignition, resulting in an extremely dangerous situation.

Purpose of the Invention The present invention solves the above-mentioned drawbacks of the conventional technology, and makes it possible to connect the power wire to the time switch motor more reliably and easily, and also to prevent damage even when high voltage pulses such as induced lightning are applied. The purpose is to realize a highly reliable time switch that does not cause any damage.

Structure of the Invention In order to achieve the above object, the time switch of the present invention has the following features:
A pair of terminals is provided through the case that constitutes the time switch body, and 3IO is installed between the terminals located inside the case.
The coil lead wires of the motor are connected to these terminals, and the power supply is connected through these terminals.By once relaying the coil lead wires to the terminals, the coil lead-out wires are connected to the terminals. In addition to preventing direct external force from being applied to the parts and preventing the risk of wire breakage, it is also easy to connect and disconnect the power supply wire, and even if the installed equipment is different, the same shape of time switch can be used for all, allowing for standardization. . In addition, by discharging the high voltage pulse through the small gap provided between the terminals, it is possible to prevent the high voltage pulse from being directly applied to the seven-point coil, thereby preventing the coil from breaking or breaking, thereby realizing a highly reliable time switch. It is something.

Page 6 Description of Embodiment Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 4 is a plan view showing the time switch according to the present invention with the cover removed, and FIG. 6 is a side view of the same time switch.

In FIGS. 4 and 6, the motor 2 is located at the bottom of the case 21.
2 is provided, and its rotational output is transmitted from the motor gear 23 to the case 2.
Gear A24 in 2. Gear B26. It is connected to a speed reducer constituted by gear C26.

The gear C26 is connected to a cam 28 which is connected with frictional resistance, and the cam 28 is connected to the shaft 27.

The lever 29 can be moved by the rotation of the cam 28, and the movable contact 30
The opening/closing operation is performed between the fixed contact 31 and the fixed contact 31. Reference numeral 32 forms a time switch body integrally with the case 21, and is integrated with the case 21 by screws 33. The movable contact 30° and the fixed contact 31 are connected to a contact terminal 34 provided on the case 21. Further, the case 21 is provided with a pair of terminals, terminal A36 and terminal B36. These terminals 71 (-) are inserted into the case 2 so that the terminals 71 (-) pass through the case 21.
They are located inside and outside of 1. And terminal A36 inside the case 21. The gap t formed by the terminal B36 is set to 3 mm or less. Terminal A35 on the outside of the case 21. The distance between the terminals B36 is sufficient for insulation and connection of the power line. The lead wire 37 from the coil of the motor 22 is connected to the terminal A36. Each is connected to terminal B36 by welding, brazing, etc.

6 to 8 show other embodiments of the terminal of the time switch according to the present invention, in which the tip of the terminal forming the gap is made at an acute angle.

In FIG. 7, the tip portion of the terminal forming the gap t is formed by opposing bent portions.

In FIG. 8, an insulator 38 is interposed at the tip portion of the terminal constituting the gap t within a range that does not increase the creeping insulation distance.

FIG. 9 is a sectional view showing the main parts of the time switch according to the present invention. FIG. 9 shows a state in which the tip of the terminal 36' forming the gap is located in a closed case constituted by the case 21' and the cover 32'.

The operation of the above configuration will be explained below.

When the shaft 27 is rotated and a time limit is set, the cam 28 rotates, and the lever 29 rides on the recess of the cam 28 and moves the movable contact 3o.
moves and closes the circuit with the fixed contact 31. At this time, the gear C26 does not rotate because it is frictionally connected to the cam 28. Thereafter, the motor 22 starts at the same time as the device starts operating, and the motor gear 23, gear A24. Gear B26. Gear C
A cam 28 rotates via 26 and opens the contact after a set time has elapsed. Power to the motor 22 is supplied via a plug connector to terminal A36. Connect to terminal B36.

High-voltage pulses such as induced lightning pass through the power line to terminal A36,
When applied to terminal B36, a discharge is generated in some parts of the air gap in the case, and by appropriately selecting the interval of the air gap t and making the discharge voltage lower than the breakdown voltage of the motor coil, it is possible to prevent this from destructive force. Obtainable.

Page 9 Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

1. Since the motor's Hiji wire is once relayed to the terminal, no external force is applied to the Hiji wire, and intermittent failures do not occur.

By making the terminal shape tab-shaped for a connector, a power line can be directly connected to the terminal. This allows the same type of time switch to be used even if the installed equipment is different, allowing for standardization and economical mass production.0 2 The terminals penetrate the case, and the width between the terminals inside and outside the case Since the terminals are different, it also serves as a stop when the terminal is removed, and the terminal can be easily fixed by simply inserting it between the case and the cover, making assembly simple and inexpensive. In addition, since it can be securely fixed, the insulation is also reliable and safe. 0 3 Even if high-voltage pulses such as those caused by induced lightning are applied to the power line and applied to the time switch, discharge will occur in the minute gap of 10 pages between the terminals. Destruction can be prevented by making this discharge voltage lower than the breakdown voltage of the motor coil.

In a device using this time switch, there will be no accidents such as the time switch stopping and continuous operation resulting in overheating and the risk of ignition, making it possible to realize an extremely safe device.

4. By configuring either of the terminals constituting the gap to have an angle on the facing surfaces, discharge can easily start due to the action of needle end discharge, and a sufficient high-voltage pulse absorption effect can be achieved. Furthermore, the gap between the gaps can be widened to the extent that discharge is more likely to start, and sufficient insulation from the commercial power source can be achieved.

5. By interposing an insulator in the gap between the terminals, the dimensions of the gap can be maintained more accurately, the discharge voltage becomes constant, and a more reliable protective effect is exhibited. If the width of the insulator is made narrower than the width of the terminals, the creepage insulation distance between the terminals will not increase by 11', and the discharge voltage will not increase.

6. By locating the smallest gap of the terminal inside the sealed case, there is no infiltration of dirt or the like into the gap, and there is no risk of insufficient insulation against the commercial power supply voltage during normal use.

Furthermore, since the discharge arc caused by the high-voltage pulse is sealed, it does not affect other equipment, resulting in a highly safe device.

[Brief explanation of the drawing]

Fig. 1 is a side view showing the external appearance of a conventional time switch, Fig. 2 is a perspective view showing the external appearance of a high-frequency heating device, which is an example of a device with a built-in time switch, and Fig. 3 is a circuit diagram of the above-mentioned high-frequency heating device. , FIG. 4 is a plan view showing the time switch according to the present invention with the cover removed, FIG. 6 is a side view of the time switch, and FIGS. 6, 7, and 8 are terminal views of the time switch. A perspective view showing another embodiment, and FIG. 9 is a partial sectional view of the same time switch. 21... Case, 22... Motor, 3
2...Cover, 36...Terminal A136
...Terminal B137...Leader wire, 38
······Insulator.

Claims (1)

[Scope of Claims] (1) A cam and a contact are provided built into a motor and a case, the cam is driven by the motor, and the contact is opened and closed by rotation of the cam, and a pair of contacts are provided through the case. A time switch ( 2] The time switch according to claim 1, wherein at least one of the pair of terminals constituting the gap has an angle on opposing surfaces. (3) The time switch is configured by a pair of terminals. The time switch according to claim 1, which has a structure in which an insulator is interposed in the minimum gap. (4) The time switch according to claim 1, which has a structure in which the minimum gap formed by a pair of terminals is located inside a sealed case. Time switch described in range 1. 2 pages