OPERATION INDICATING DEVICE FOR ELECTROMAGNETIC RELAY

Abstract: An operation indicating device and apparatus for a hinged type electromagnetic relay (1), comprising: a working member (10) supported so as to be able to interlock with a movable contact portion, said working member being disposed in a space distant from a contact portion; and an indicating member (11) coupled to said working member and rotatably supported by a shaft (12), said indicating member having a recognizable indicating portion (11c), said indicating member being rotated by said working member interlocking with said movable contact portion during the operation of said movable contact portion, the indicating portion of said indicating member thus rotated arriving at a position corresponding to an indication window (8a) formed in a case cover (8) of the electromagnetic relay.

Description: BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to an operation indicating device for an electromagnetic relay and in particular to an operation indicating device for an electromagnetic relay wherein the display configuration is simplified to substantially widen the space within the case cover and make it effectively usable. DESCRIPTION OF THE RELATED ART Some conventional electromagnetic relays have an operation indicating device for indicating the open/close states of the relays. One example of their configurations is shown in Figs. 8A and 8B. Fig. 8A is the side view of a longitudinal section of a conventional electromagnetic relay and Fig. 8B is the front view of a longitudinal section of the electromagnetic relay. In this configuration example, a slender operation indicating member 9 made of an elastic material is erectly installed on a base 2 of the electromagnetic relay 1. A piece 9a formed by cutting and raising one portion of a middle part in the operation indicating member 9 is linked to an insulation plate 5a attached to an armature 5. When the contact of the electromagnetic relay 1 is closed, i.e., when the armature 5 is attracted to a core 3a of an electromagnetic coil 3, the operation indicating member 9 is drawn to the electromagnetic coil 3 so that an indicating portion 9b formed by bending the upper end of the operation indicating member 9 in a reversed L form may be confronted by an indication window 8a formed in a case cover 8. As a result, the operative state of the electromagnetic relay 1 is indicated through the window 8a. Reference numerals 4, 6 and 7 denote a yoke, a movable contact plate and a return spring, respectively. In the above described operation indicating device of the electromagnetic relay 1, the operation indicating member 9 is so disposed as to be opposed to the armature 5. The space near the contact is thus reduced. As a result, it is difficult to obtain a sufficient insulation distance, and insulation is deteriorated by the deposition of carbon caused by arc when the contact is opened or closed. The problem of limitation in the number of contact poles is also incurred. DE-A-2 818 604 discloses an electromagnetic relay being quite similar to that one as described above. Accordingly, this known electromagnetic relay is tainted with the same disadvantages as mentioned above. Moreover, the working member in this known electromagnetic relay is affected in an attracting operation and the operational stroke of the display portion is not adapted to be moved over a large range. EP-A-0 098 480 discloses an electromagnetic relay in which an indication member is constructed so as to rotate around a pivot shaft in response to the operation of a working member. In this known electromagnetic relay the return voltage is affected and the operational stroke of the display portion cannot be moved along a large range since the rotation angle is restricted. SUMMARY OF THE INVENTION It is the object of the present invention to provide an electromagnetic relay in which the space near the contact is broadened to use the space effectively, in which a sufficient insulation distance is assured to prevent the insulation deterioration by simplifying the configuration thereof and in which the working member is not affected in an attracting operation and the operational stroke of the display portion is adapted to be moved over a large range. This object is solved by an electromagnetic relay as claimed in claim 1. When the armature is activated in such structure, the working member connected to the armature is activated. Accordingly, the indicating member coupled to the working member is rotated around a supporting shaft serving as the fulcrum. The indicating portion disposed on the indicating member thus moves to a position located immediately below an indication window formed in the case cover. Accordingly, it becomes possible to confirm the operation of the electromagnetic relay by observing the indicating portion of the indicating member through the indication window. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic perspective view for illustrating the internal structure of an electromagnetic relay and the external case of the relay as well as the relation between them; Fig. 2 is a schematic plan view for illustrating the configuration of an operation indicating device; Figs. 3 to 7 are schematic, partial perspective views for illustrating alternate embodiments of the operation indicating device of the electromagnetic relay; Fig. 8A is a side longitudinal section of a conventional operation indicating device for the electromagnetic relay; and Fig. 8B is a front longitudinal section of the conventional operation indicating device for the electromagnetic relay. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will now be described by referring to appended drawings. In the following figures, the same components as those shown in Figs. 8A and 8B are denoted by corresponding identical reference characters, respectively. In Fig. 1, a base end portion 10a of a working member 10 made of a resin material taking the shape of a slender plate is affixed to a projection 5b for retaining a return spring 7 formed on the upper end of an armature 5 of an electromagnetic relay 1 by a binding agent or the like. A free end portion 10b which is the other end of the working member 10 is projected into the space above a yoke 4 substantially in parallel to the upper face 4a of the yoke. The free end portion 10b of the working member 10 is rotatably coupled to the middle part of an indicating member 11 made of a resin material taking the shape of a slender plate by a shaft pin 13. A base end portion 11a of the indicating member 11 has an axis rotatably supported by a supporting shaft 12 which is erected on a position of the upper face 4a of the yoke. The other end of the indicating member 11, i.e., a free end portion 11b is colored red, for example, to form an indicating portion 11c. Alternatively, the indicating member 11 may be entirely colored. When the armature 5 is attracted to the core (not illustrated) of an electromagnetic coil 3, therefore, the working member 10 moves in a direction opposite to the operation direction of a movable contact plate 6 to draw the indicating member 11. Accordingly, the indicating member 11 is rotated around the supporting shaft 12 to move the indicating portion 11c toward the armature 5. An indication window 8a is formed beforehand at a position of the case cover 8 corresponding to the position whereto the indicating portion 11c moves. Thus the indicating portion 11c can be observed through the indication window 8a. It is possible to confirm the operation indication of the electromagnetic relay 1. The indication window 8a can be formed by sticking an opaque seal 14 having a rectangular opening onto the upper face of a transparent case cover 8. Or the indication window 8a may also be formed by providing the case cover 8 itself with an opaque part and a transparent part. In the operation indicating device thus constructed, the operation stroke of the indicating portion 11c can be changed by changing a position on the indicating portion 11 whereto the working member 10 is coupled (or by changing the ratio x : y) as shown in Fig. 2. Therefore, the operation indicating device can be used in conformity with the types of various electromagnetic relays. Further, it is also possible to couple the working member 10 to the indicating member 11 so that a fulcrum which supports the indicating member 11 rotatably may be located at the middle position of the indicating member 11. Figs. 3 to 7 show other embodiments of the operation indicating device. In Fig. 3, the indicating member 11 is made with the supporting shaft 11d as a single body to take the shape of letter L. And the supporting shaft 11d is rotatably inserted into a shaft hole opened on an upper face 4a of the yoke. In Fig. 4, a supporting shaft 15a is erected on a fixed plate 15 having a section resembling the shape of caught in an edge of the upper face 4a of the yoke. The indicating member 11 has an axis rotatably supported on the supporting shaft 15a. In Fig. 5, molded resin forming the flange of a bobbin 3b of an electromagnetic coil 3 is so extended as to be used as a supporting shaft 3c. In Fig. 6, a portion of the upper face 4a of the yoke is cut and fold back upwardly to form a supporting shaft 4b for supporting the indicating member 11 at the rotation axis thereof. In Fig. 7, a supporting shaft 8b is suspended inside the upper face of the case cover 8, and the indicating member 11 is rotatably attached to the supporting shaft 8b. In each of the above described embodiments, it is also possible to dispose the indicating portion 11c located on a end of the indicating member 11 nearer the indication window 8a of the case cover 8 by forming a stairlike bended portion in the indicating member 11. On the other hand, various methods for attaching the working member 10 can be considered. For example, resin of the insulation plate 5a attached to the armature 5 may be extended to fix the working member 10 thereto. Or the upper end of the movable contact plate 6 fixed to the insulation plate 5a may be extended upward to fix the working member 10 thereto. Alternatively, an insulation sheet which is not illustrated in the figures and which is disposed between the armature 5 and the insulation plate 5a may be extended to fix the working member 10 thereto. In this way, further various structures for fixing the working member 10 and the indicating member 11 can be considered by combining the above described structures. In accordance with the present invention described above, the mechanism for indicating the operation is entirely disposed above the electromagnetic coil portion. Therefore, it is a matter of course that the position adjustment can be simply carried out. In addition, the surroundings of the contact portion can be made similar to a conventional electromagnetic relay which is not provided with the operation indicating device. Therefore, the reduction in insulation distance caused by the presence of the operation indicating member is obviated. The insulation deterioration is also prevented. In addition, the number of contact poles need not be limited. Effects in the operation can also be attained. That is to say, the attraction operation of the armature and the change in return voltage are hardly affected owing to the structure using the link mechanism. Further, the number of components for the structure is not large. Accordingly, the simple mechanism results in improved reliability, reduced fabrication steps and a lower cost.

Claims: Electromagnetic relay (1) comprising: a working member (10) connected to a movable contact portion (5, 5a, 6) and an indicating member (11) coupled to said working member (10), said indicating member (11) having a recognizable indicating portion (11c), said indicating member (11) being rotated by said working member (10) interlocking with said movable contact portion (5, 5a, 6) during the operation of said movable contact portion (5, 5a, 6), the indicating portion (11c) of said indicating member (11) thus rotated arriving at a position corresponding to an indication window (8a) formed in a case cover (8) of the electromagnetic relay (1), characterized in that said working member (10) and said indicating member (11) are disposed over an electromagnetic coil (3) portion so as to operate in a plane which is above and parallel to the upper face (4a) of a yoke (4), said indicating member (11) is rotatably supported by a shaft (12) and a shaft pin (13) is used for coupling said working member (10) and said indicating member (11). Electromagnetic relay according to claim 1, wherein said movable contact portion comprises an armature (5). Electromagnetic relay according to claim 1, wherein said movable contact portion comprises an extension of resin of an insulation plate (5a). Electromagnetic relay according to claim 1, wherein said movable contact portion comprises an extension of the upper end of a movable plate (6). Electromagnetic relay according to claim 1, wherein the coupling point between said working member (10) and said indicating member (11) can be arbitrarily changed. Electromagnetic relay according to claim 1, wherein said indicating member (11) is formed in the shape of letter L, and a part of said indicating member (11) is used as a supporting shaft (11a) and rotatably inserted into a shaft hole formed in the upper face (4a) of the yoke (4). Electromagnetic relay according to claim 1, wherein said indicating member (11) has an axis rotatably supported by a supporting shaft (15a) erected on a fixed plate (15) having a section like the shape of the letter U, and said fixed plate (15) is caught in an edge portion of the upper face (4a) of said yoke (4). Electromagnetic relay according to claim 1, wherein said indicating member (11) has a rotation axis supported by an extension of molded resin forming a flange of a bobbin (3b) of the electromagnetic coil (3). Electromagnetic relay according to claim 1, wherein said indicating member (11) has an axis supported by a supporting shaft (4b) which is erected by cutting and folding back upwardly a portion of the upper face (4a) of said yoke (4). Electromagnetic relay according to claim 1, wherein said indicating member (11) is rotatably attached to a supporting shaft (8b) suspended inside the upper face of said case cover. Electromagnetic relay according to claim 1, wherein said indicating member (11) is entirely or partially coloured to form said indicating portion (11c).

Inventors: KASAMA, TOSHIYUKI, SASAKI, NARUHITO, TSUJIMURA, SHIGERU, WATANABE, TOSHIO
Applicants: IDEC IZUMI CORPORATION
Application year: 1987
Main classification: H01H50
IPC codes: H01H50