JPS639334B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a return button, a switching mechanism from manual return to automatic return, and a case provided with at least one manual operation mechanism on an end surface opposite to the mounting surface. The present invention relates to a thermal protection relay having a thermal protection relay.

In one known protection relay of the above-mentioned type (DE 1802835), a button for resetting activated contacts projects on the end face of the protection relay opposite to the mounting surface. The position of the adjustment dial for setting the trip current value is not shown in the above specification. However, it is known that an adjustment dial can be freely provided on the end face of the protective relay.

An object of the present invention is to provide a simple thermal protection relay that can at least set an adjustment dial to a predetermined value and that can prevent subsequent movement of the manual operating mechanism including the adjustment dial.

In order to achieve the above-mentioned object, the present invention includes a return button, a switching mechanism from manual return to automatic return,
In a thermal protection relay having a case having a manual operation mechanism on the end face opposite to the mounting surface, the manual operation mechanism includes an adjustment dial for setting an overcurrent value and a pushbutton for checking the operation of the relay contacts. The adjustment dial and pushbutton are covered by a transparent, snap-on, lead-sealable cover. Covering the adjustment dial prevents it from being moved from the set position, and covering the push button for checking the operation of the relay contact prevents the push button from being pressed accidentally and causing the load to operate. Prevent it from stopping. Moreover, if this push button is covered with the cover together with the adjustment dial, the safety against erroneous operation of the protection relay can be improved without actually requiring additional costs. Similarly, to improve safety, if the cover extends by its extension over the combined return switch button, the cover can be manufactured more cheaply than if each cover is provided with its own cover, and the combined return switch button is To prevent the return method from being changed due to careless operation. This extension is
It may be breakable so that it can be removed if not needed. In order to prevent the manual operating mechanism, which is arranged approximately at the same height as the return switching button, from being operated accidentally, the extension part is provided with an extension button for the return switching button, which is under the action of a return spring. That is advantageous. Furthermore, it is advantageous for a tool receptacle to be provided in the cover part covering the pushbutton, so that the operation of the relay can only be checked by the responsible person.

The structure and operation of one embodiment of the present invention will be explained in detail with reference to the drawings.

The protective relay 1 is provided with an adjustment dial 3 for setting a trip overcurrent value and a push button 4 for checking the operation of the relay contacts on the upper end surface 2. This pushbutton 4 mechanically acts on a counter-contact part, not shown, which is constructed as a leaf spring of a normally closed contact, so that tripping of the relay can be checked by pressing the pushbutton 4. . The reference numeral 5 in FIG. 1 is a compound return switching button used to switch between returning activated contacts and switching between manual return and automatic return. By pressing the button 5 after the relay has tripped, the relay can be put back into use. Further, by pressing and turning the button 5, switching from manual operation return to automatic return is performed, so manual return is unnecessary in this state. The connection screws of the protection relay to the auxiliary switch are marked with the reference numeral 6, and the connection conductors on the inlet and outlet sides of the protection relay are marked with the reference numeral 7 or 8. Now, the upper end surface 2 of the protective relay 1 is covered with a transparent cover 9 by a snap-on method. The cover 9, as shown in FIG.
The cross section is approximately U-shaped, and hook-shaped projections 10 and locking projections 11 are provided at portions corresponding to the legs. The recess provided in the protective relay corresponding to the hook-shaped projection 10 or the locking projection 11 is not shown. The part corresponding to one leg has an opening 1 used for inserting tools and removing the cover.
3 protrusions 12 are provided, and the cover can only be removed using a tool. A series of holes 1 in the cover 9 shown in FIG.
The part to the right of 7 serves to cover the adjustment dial 3 and the operation check push button 4, and the part to the left serves to cover the return switching button 5. button 4
A hole 14 is provided in the area covering the holes 1 and 5 to allow access to the connecting screw 6. A box-shaped protrusion 15 of the cover 9 that covers the push button 4 is provided with a tool insertion port 16.
Relay operation checks can only be performed using a sharp-edged tool. The left-hand part of the cover shown in FIG. 3 is connected to the right-hand part through a series of holes 17, so that separation of the two parts is possible without difficulty. As shown in FIG. 2, in the breakable portion 18 on the left side, an extension button 19 with a large head is attached to a bushing 2 protruding from the cover 9 for the return switching button 5.
1 so as to be movable against the force of a spring 20. The spring 20 is supported on the one hand by the head of the extension button 19 and on the other hand by the bushing 21.
This is done by a bridge 22 formed diagonally within the holder and engaging between the slitted arms of the extension button 19. Since the head of the extension button 19 has a large area and is sufficiently displaced upward from the protrusion 15 or the push button 4, there is no risk that the push button 4 will be operated by mistake when the return switching button 5 is operated.
Furthermore, the breakable portion 18 is an outer curved portion 23.
, where an indicator pin 24 for tripping of the relay is visible.

To allow proximity to the operating elements of the relay,
The left side portion 18 of the cover 9 can be removed without breaking the lead seal even after the cover body is placed over the cover body and the lead seal is sealed. The cover can be placed on the front of the relay in a snap-on manner without tools. However, it is practically impossible to remove the cover without using a tool. Because the cover is made of transparent material, reading of the set current value can be carried out through the cover. Since the hole 14 is provided, the connection of the conductive wire to the terminal screw 6 is not hindered even when the cover is covered, as described above.

According to the present invention described above, the adjustment dial for setting the overcurrent value and the push button for checking the operation of the relay contact are covered with a transparent cover that can be snapped on and sealed with lead. This means can prevent the set current value from being changed by operating the adjustment dial after setting the overcurrent value, and can also prevent load operation from being caused by accidentally pressing the push button for checking the operation of the relay contact. You can prevent it from stopping,
It is possible to improve the safety against erroneous operation of the thermal protection relay. Furthermore, since the cover is transparent, there is an advantage that the set current value can be checked even after the cover is attached.

[Brief explanation of the drawing]

1 is a plan view of a protective relay covered with a cover according to the present invention, FIG. 2 is a side view of the protective relay of FIG. 1, FIG. 3 is a plan view of the cover, and FIG. 4 is a cover of FIG. 3. The side views of FIGS. 5 and 6 are cross-sectional views of the cover taken along the lines of FIG. 1...Protective relay, 2...Front, 3...Adjustment dial, 4...Push button for operation check, 5...
Return switching button, 6... Connection screw for auxiliary switch, 7, 8... Connection conductor, 9... Transparent cover, 1
0... hook-shaped projection, 11... locking projection, 12... protrusion, 13... opening, 14... hole, 15... box-shaped protrusion, 16... tool insertion port, 17... hole, 1
8... Breakable part, 19... Extension button, 2
0... Spring, 21... Bush, 22... Bridge, 23... Outer curved portion, 24... Display pin.

Claims (1)

[Scope of Claims] 1. A thermal protection relay having a return button, a switching mechanism from manual return to automatic return, and a case in which a manual operation mechanism is provided on the end face opposite to the mounting surface, The manual operating mechanism is an adjustment dial for setting the overcurrent value and a pushbutton for checking the operation of the relay contacts, and that the adjustment dial and pushbutton are covered by a transparent, snap-on, lead-sealable cover. Features thermal protection relay. 2. The thermal protection relay according to claim 1, characterized in that the cover extends over the composite return switching button by an extension thereof. 3. The thermal protection relay according to claim 2, wherein the extended portion of the cover is breakable. 4. The thermal protection relay according to claim 1, characterized in that the cover portion that covers the push button has a tool insertion port. 5. The thermal protection relay according to claim 2 or 3, characterized in that the extended portion of the cover has an extension button for use as a return switching button, which is under the action of a return spring.