JPS6324603Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to the improvement of a so-called electromagnetic switch that combines an electromagnetic switch with a push button and a thermal relay, and aims to reduce the size and cost.

Various structures are known for this kind of device, but the most common one is that the push button (on button, off button) is installed inside the case as one unit, and electromagnetic contact is used. The necessary wiring has been installed for the device, thermal relay, and push button unit. With such a structure, since the overall size is determined by the size of each unit, there is a limit to miniaturization, and there are also problems in terms of cost.

This idea solves these problems. An embodiment of this invention will be explained with reference to the drawings.
First, in FIGS. 1 and 2, 1 is a case, and 2 is a cover that covers the front part of the case 1. As shown in FIGS. These case 1 and cover 2 are molded from synthetic resin. As shown in Figure 1, the cover 2
An on button 3 and an off button 4 are attached to the button 3 so as to be able to be pressed and returned to normal by a structure that will be described later.
As shown in FIGS. 1 and 4, the case 1 and the cover 2 are fitted at their upper parts and fixed with a set screw 5 at the lower part.

As shown in FIGS. 3 and 4, an electromagnetic contactor 6 and a thermal relay 7 are installed inside the case 1. 8 in FIG. 3 is a mounting hole. In this electromagnetic switch, the on button 3 has a structure that shorts the terminal screw of the self-holding circuit of the electromagnetic contactor 6 built into the case 1, and the off button 4 has a structure that is integrally molded into the case 1. The structure is such that a movable contact piece and a contact spring are incorporated into a slit provided in the same direction, and this point will be described in detail below.

As shown in FIG. 4, the cover 2 is integrally formed with recesses 2a and 2b having a substantially U-shaped cross section. The recesses 2a and 2b support the on button 3 and the off button 4 so as to be pressable, respectively. Return springs 9 are provided between the recesses 2a and 2b and the on button 3 and off button 4, respectively.
10 is interposed to provide restoring force to the on button 3 and the off button 4.

As shown in FIGS. 5 and 6, a movable ON contact 11, which is a U-shaped shorting plate with both ends open outward, is attached to the tip of the ON button 3 by a screw 12. . As shown in FIG. 6, an on contact spring 13 is interposed between the on button 3 and the movable on contact 11, and a force in the direction away from the on button 3 is applied to the movable on contact 11. is giving. The movable on-contact 11 faces the terminal screws 14 and 15 of the electromagnetic contactor 6, and comes into contact with the on-button 3 when it is pressed. The terminal screws 14 and 15 form a self-holding circuit of the electromagnetic contactor 6 as described later.

A push rod 16 is attached to the tip of the off button 4 with a screw 17. The tip of the push rod 16 is
It faces a movable off contact 18 supported by the structure described below. As shown in FIG. 4, a part of the case 1 protrudes toward the cover 2, and this protrusion 1
slit 19 (seventh
(see figure), the above-mentioned movable off contact 18, which is a movable contact piece, is supported by being pushed toward the push rod 16 by a contact spring 20. The contact spring 20 is supported by a circular portion 19a formed in the center of the slit 19. Fixed off contacts 21 and 22 are connected to screws 23 and 2 at the upper and lower parts of the protrusion 1a.
4 and receives the movable off contact 18 pushed by the contact spring 20.

Next, the operation of this electromagnetic switch configured as described above will be explained. This electromagnetic switch is connected and used as shown in FIG. That is, 25 and 26 are the lines of the operating power source, and these lines 25 and 26 are
In between, an off switch 27 consisting of fixed off contacts 21, 22 and a movable off contact 18, and a terminal screw 1
4, 15 and a movable on-contact 11, a coil 29 of an electromagnetic contactor 6, and a thermal relay 7 are connected in series. Note that a self-holding contact 30 is provided between the terminal screws 14 and 15 so as to be openable and closable.

If the on button 3 is now pushed in the direction P in FIG. 15,
Since a current flows through the coil 29 and the thermal relay 7, the electromagnetic contactor 6 is activated and a circuit (not shown) is connected. At the same time, the self-holding contact 30 short-circuits the terminal screws 14 and 15, so that the on button 3 can be released. To turn off the electromagnetic contactor 6, just press the off button 4.

It is best to make the dimensions of each part of the on button as follows. That is, the dimensions of each part in FIG. 6 are S, T, U,
In V, W, S>W, U>T, U-T=ε, ε
<V. Here, ε is the wipe amount (the overtravel amount of the pushing amount), and by providing this, the contact pressure of the ON contact spring 13 can be obtained. The push-in stopper position of the on button 3 is at the front surface 6a of the electromagnetic contactor 6 (see FIG. 6).

Since this invention is constructed as described above, it has the following effects.

(1) The electromagnetic switch is housed in a case, and the on button and off button are attached to the cover that covers the front of the case so that they can be pressed back to normal. It can be made more compact than a unit installed inside the case.

(2) According to (1) above, the assembly is completed by assembling the case in which the electromagnetic switch is housed, the cover to which the on button to which the shorting plate is connected and the off button to which the push rod is connected are attached. Assembly is easy and costs can be reduced.

[Brief explanation of drawings]

Figure 1 is a front view of the electromagnetic switch according to this invention.
Figure 2 is a side view of the thing in Figure 1, Figure 3 is a front view showing the inside of the thing in Figure 1, Figure 4 is a sectional view of the thing in Figure 1, and Figure 5 is the main part of the electromagnetic contactor. 6 is a sectional view showing the main part of FIG. 4,
Figure 7 is a front view showing a part of the thing in Figure 4;
The figure is a circuit diagram showing a connection circuit. 1: Case, 1a: Protrusion, 2: Cover, 2
a, 2b: recess, 3: on button, 4: off button, 5: set screw, 6: electromagnetic contactor, 7: thermal relay, 9, 10: return spring, 11: movable on contact, 18: movable off contact , 19: Slits.

Claims (1)

[Scope of utility model registration request] An electromagnetic contactor and a thermal relay are housed in a case and a cover, and when an on button is operated, the electromagnetic contactor and the thermal relay are energized to form a self-holding circuit, and when an off button is operated, the self-holding circuit is released. In an electromagnetic switch with a push button, an on button and an off button are attached to the cover so as to be press-returnable, and a terminal screw of a self-holding fixed contact of the electromagnetic contactor is exposed on the surface of the electromagnetic contactor. At the same time, the case is provided with an opening/closing contact portion having a normally closed contact configuration connected in series to the self-holding circuit, and a shorting plate is coupled to the on button to short-circuit between the terminal screws of the self-holding fixed contact. An electromagnetic switch with a push button, characterized in that a push rod for operating a movable contact of the normally closed contact portion is coupled to the off button.