Small sized electromagnetic relay

Abstract: In an electromagnetic relay a movable contact spring and a stationary contact spring (10) are inserted by molding a portion (91) of the movable contact spring and a portion (101) of the stationary contact spring (10) within the base block (8). The portions (91, 101) of the contact springs within the base block (8) are made larger than the respective portions thereof outside of the base block.

Description: The present invention relates to an electromagnetic relay according to the preamble of claim 1, wherein a movable contact spring and a stationary contact spring are inserted by moulding into a base block. When fixing contact springs to a base block, a pressure method or an inserting-by-moulding method is used. According to the latter method, the moulding thickness can be made smaller than that of the former method, and this helps to reduce the size of the relay. US-A-4,656,733 discloses an electromagnet relay having an electromagnet assembly and a base block assembly for fixing said electromagnet assembly thereto, the base block assembly comprising a base block, a moveable contact spring, and a stationary contact spring, the movable contact spring (9) and the stationary contact spring being inserted by moulding into said base block, the movable contact spring having a slit extending longitudinally from the end thereof carrying the movable contact. The relay in accordance with the invention is characterised in that the movable contact is on only one side of the slit at the said end of the movable contact spring and in that the other side of the slit at the said end of the movable contact spring is inserted at its free end into the base block, the arrangement serving to produce an increase in the effective length of the movable contact spring; and in that the width of a portion of the movable contact spring and of the stationary contact spring within the base block is larger respectively than that of a portion of the movable contact spring and of the stationary contact spring outside the base block. The present invention will be more clearly understood from the description as set forth below, with reference to the accompanying drawings, wherein: Fig. 1 is an exploded, perspective view illustrating an embodiment of the electromagnetic relay according to the present invention; Fig. 2 is a longitudinal cross-sectional view of the assembled relay of Fig. 1; Fig. 3 is an enlarged perspective view of the contact springs of Fig. 1; Figs. 4A and 4B are enlarged plan and side views of the contact springs and the card of Fig. 1; and Fig. 5 is an enlarged perspective view of the card of Fig. 1. DESCRIPTION OF THE PREFERRED EMBODIMENTS In Fig. 1 and 2, which illustrates an embodiment of the present invention, reference X designates an electromagnet assembly, and Y designates a base block assembly. Reference numeral 1 designates a bobbin on which a winding 2 is wound. The bobbin 1 has two collars la and 1b, and block-shaped portions 1c and ld protruded from the collar 1b. Winding terminals 3a and 3b are inserted by pressure into the block-shaped portions lc and 1d, respectively, and the ends of the winding are fixed to the winding terminals 3a and 3b. Reference 4 designates a core which penetrates the center of the bobbin 1 and is fixed by a yoke 5. Note, a magnetic pole portion of the core 4 is indicated by 4a. Reference 6 designates an armature which is fixed to an end of a L-shaped hinge spring 7, the other end of which is fixed to the yoke 5 by inserting the protrusions (not shown) thereof into holes 7a and 7b of the hinge spring 7, whereby the electromagnet assembly X is completed. Next, the base block assembly Y is explained below. A base block 8 includes an approximately cylindrical insulating barrier 8a having an opening through which the electromagnet assembly X is inserted. Also, a movable contact spring 9 having a contact 9a and a terminal 9b and a stationary spring 10 having a contact 10a are inserted by molding into the base block 8. Note that the body of the movable contact spring 9 and a terminal 9b thereof can be formed separately or integrally. Also, a slit 9c extends longitudinally from one end of the movable contact spring 9, to thereby effectively increase the length of the movable contact spring 9, i.e., reduce the stiffness thereof. The movable contact 9a is on one side of the slit 9c at the said end thereof on the opposite side of the slit 9c to the terminal 9b. Further, the stationary contact spring 10 is approximately L-shaped, to thus effectively increase the length of the stationary contact spring 10, i.e, reduce the stiffness thereof. As a result, after the winding 2 is excited, whereby the contact 9a of the movable contact spring 9 is in contact with the contact 10a of the stationary contact spring 10, the stationary contact spring 10 can be moved to easily obtain a desired contact follow through. Reference 12 designates a two-parallel-arm type and card for transmitting a motion of the armature 6 to the movable contact spring 9. For this purpose, curled portions 12a and 12b of the card 12 are inserted into holes 6b and 6c of the armature 6. Also, reference 13 designates a box for accommodating the body of relay. When the body of the relay is accommodated in the box 13, the box 13 is adhered by adhesives to the base block 8. In this case, the adhesives are inserted in through holes 8b and 8c of the base block 8, but the adhesive may be spilt to form a hinge portion 5a of the yoke 5. To avoid this, two parallel rails (protrusions) 8d and 8e are provided at the base block 8 on the opening side of the barrier 8a. The parallel rails 8d and 8e are positioned inside of the block-shaped portions 1c and 1d when the electromagnet assembly X is inserted into the cylindrical insulating barrier 8a of the base block 8, and thus the parallel rails 8d and 8e also serve as guides for the electromagnet assembly. The movable contact spring 9 (in this case, the terminal 9b) and the stationary contact spring 10 of Figs. 1 and 2 are explained in more detail with reference to Fig. 3. A portion 91 of the terminal 9b within the base block 8 is made wider than a portion 92 of the terminal 9b outside of the base block 8, to ensure a secure adhesion of the terminal 9b of the movable contact spring 9 to the base block 8. Also, a portion 93 of the terminal 9b towards the external terminal 94 thereof is made slimmer. As a result, even when a large force is applied to the external terminal 94, such a large force is absorbed by the slim portion 93, to thus avoid a transformation of the movable contact spring 9. Similarly, a portion 101 of the stationary contact spring 10 within the base block 8 is made wider than a portion 102 of the stationary contact spring 10 outside of the base block 8, to thus ensure a secure adhesion of the stationary contact spring 10 to the base block 8. Also, a portion 103 of the stationary contact spring 10 towards the external terminal 104 thereof is made slimmer. As a result, even when a large force is applied to the external terminal 104, such a large force is absorbed by the slim portion 103, to thus avoid a transformation of the stationary contact spring 10. Also, although the movable contact spring 9 and the stationary contact spring 10 are arranged at different faces spaced along the longitudinal direction of the relay, since the slim portion 93 of the terminal 9b is bent, both of the external terminals 94 and 104 are arranged at the same face with respect to the longitudinal direction of the relay. The terminal 9b of the movable contact spring 9 is further securely adhered to the base block 8. The card 12 of Figs. 1 and 2 is explained in more detail with reference to Figs. 4A, 4B, and 5. That is, a portion 12c of the card 12 is fitted on an upper portion of the movable contact spring 9, and simultaneously, a protrusion 12d of the card 12 penetrates through a hole 9d of the movable contact spring 9, thus avoiding a separation of the card 12 from the movable contact spring 9. Since the movable contact spring 9 and the stationary contact spring 10 are located on an opposite sides of the electromagnetic assembly X with respect to the base block 8, it is possible to obtain a sufficient distance between the electromagnet and the contacts, thus improving the anti-surging characteristic and anti-noise characteristic of the relay. The assembly operation of the relay of Figs. 1 and 2 is explained. The winding terminals 3a and 3b are fixed by a pressure insertion thereof in the holes of the block-shaped portions 1c and 1d of the bobbin 1. Next, the core 4 is inserted in the bobbin 1 having the winding 2 thereon, and an end of the core 4 opposite to the magnetic pole face 4a thereof is caulked at the yoke 5, to thus complete a core assembly X1. Further, the armature 6 is caulked at a portion 6a of the hinge spring 7, to thus complete an armature assembly X2. Thereafter, holes 7a and 7b of the armature assembly X2 are fitted into the respective protrusions (not shown) of the under face of the yoke 5 of the core assembly X1, to thus complete the electromagnet assembly X. Then, the electromagnet assembly X is inserted into the cylindrical insulating barrier 8a of the base block 8, and the armature 6 is linked by the card 12 to the movable contact spring 9, and thereafter, the entire relay is covered by the box 13, to thus complete the overall assembly thereof. In this assembled relay, since the protrusion 12d of the card 12 is inserted into the hole 9d of the movable contact spring 9, the card 12 cannot be separated from the movable contact spring 9. Also, noise generated from the contacts of the movable contact spring 9 and the stationary contact spring 10 is not transmitted to the winding 2, due to the long distance therebetween, and therefore, a special noise shield is not required, which reduces the number of components. The operation of the relay of Figs. 1 and 2 is explained below. In a standby state in which no current is supplied to the winding 2, a force of the hinge spring 7 and a force of the movable contact spring 9 via the card 12 are applied to the armature 6, so that the armature 6 is separated from the magnetic pole face 4a of the core 4, and thus the contact 9a the movable contact spring 9 is opened with respect to the contact 10a of the stationary contact spring 10. Next, when a current is supplied to the winding 2, to excite same, the armature 6 is attracted to the magnetic pole face 4a of the core 4, whereby the armature 6 is rotated in the clockwise direction at the portion 5a. As a result, the movable contact spring 9 is moved toward the stationary contact spring 10 by a motion of the card 12 associated with the armature 6, and thus the contact 9a of the movable contact spring 9 abuts against the contact 10a of the stationary contact spring 10. When the current supplied to the winding 2 is shut off, the relay is restored to the original state thereof by a restoring force of the movable contact spring 9 and the stationary contact spring 10. As explained above, the electromagnetic relay according to the present invention can be made in a small size, which improves the anti-surging characteristic and the anti-noise characteristic.

Claims: An electromagnetic relay having an electromagnet assembly (X) and a base block assembly (Y) for fixing said electromagnet assembly (X) thereto, the base block assembly (Y) comprising a base block (8), a movable contact spring (9), and a stationary contact spring (10), the movable contact spring (9) and the stationary contact spring (10) being inserted by molding into said base block (8), the movable contact spring (9) having a slit (9c) extending longitudinally from the end thereof carrying the movable contact (9a); characterised in that the movable contact (9a) is on only one side of the slit (9c) at the said end of the movable contact spring and in that the other side of the slit at the said end of the movable contact spring is inserted at its free end into the base block (8), the arrangement serving to produce an increase in the effective length of the movable contact spring (9); and in that the width of a portion of the movable contact spring (9) and of the stationary contact spring (10) within the base block (8) is larger respectively than that of a portion of the movable contact spring (9) and of the stationary contact spring (10) outside the base block (8). An electromagnetic relay as set forth in claim 1, wherein the stationary contact spring (10) has an approximately L-shape, thereby to increase the effective length thereof in accordance with the shape of said movable contact spring (9) having said slit (9c). An electromagnetic relay as set forth in claims 1 or 2, wherein the movable contact spring (9) has an external terminal (94) at an extension thereof, and the stationary contact spring (10) has an external terminal (104) at an extension thereof, a portion of said movable contact spring (9) and of said stationary contact spring (10) within said base block (8) near said external terminals (94, 104) being made partially slimmer. An electromagnetic relay as set forth in any of the preceding claims, wherein a portion of the movable contact spring (9) or of the stationary contact spring (10) within said base block (8) is bent. An electromagnetic relay as set forth in any of the preceding claims, wherein the electromagnet assembly (X) comprises: a core (4); a bobbin (1) for insertion of the core (4) therein; a winding (2) wound on the bobbin (1); an armature (6) provided at the opposite end of the core (4) to the movable contact spring (9) and the stationary contact spring (10); and a card (12) for connecting the armature (6) to the movable contact spring (9), the card (12) having a portion (12c) for engaging an upper portion of the movable contact spring (9), and a portion (12d) to be inserted into a hole (9d) provided in the movable contact spring (9). An electromagnetic relay as set forth in claim 5, wherein said card (12) further has two parallel arms (12a, 12b). An electromagnetic relay as set forth in claim 6, wherein said electromagnet assembly (X) further comprises an approximately cylindrical insulating barrier (8a) for covering the winding (2), the two parallel arms (12a, 12b) of said card (12) being positioned on opposite sides of the upper part of the insulating barrier (8a). An electromagnetic relay as set forth in claim 7, wherein said insulating barrier (8a) has an opening through which the electromagnet assembly (X) is inserted.

Inventors: KOBAYASHI ATSUTO, TOMONO NOBORU, KOBAYASHI, ATSUTO, TOMONO, NOBORU
Applicants: TAKAMISAWA ELECTRIC CO, TAKAMISAWA ELECTRIC CO., LTD.
Application year: 1991
Main classification: H01H50
IPC codes: H01H50