EP0423834A2

EP0423834A2 - Electromagnetic relay

Info

Publication number: EP0423834A2
Application number: EP90120252A
Authority: EP
Inventors: Yoichi Omron Corporation Nakanishi; Ryuichi Omron Corporation Sato; Hiroyuki Omron Corporation Sagawa; Kazumi Omron Corporation Sako; Masayuki Omron Corporation Noda
Original assignee: Omron Corp; Omron Tateisi Electronics Co
Current assignee: Omron Corp
Priority date: 1989-10-20
Filing date: 1990-10-22
Publication date: 1991-04-24
Also published as: EP0423834A3

Abstract

The electromagnetic relay of the present invention ensures smooth operating characteristic as a relay for an elongated lifetime, because the movable iron piece turns on the same plane as the movable contact piece. Moreover, the operating characteristic can be adjusted from the lateral side even after assembling work and even with the inner components kept mounted. This is because a front end of the fixed contact terminal is projected sideways from the lateral face of the base, and the receiver part of the common terminal is bent outwards. In the electromagnetic relay of the present invention, the movable contact piece block is united with the movable iron piece through a secondary insertion-molding, and the base is fixed to the electromagnet block by using a solvent, thereby requiring no positioning accuracy of components.

Description

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention generally relates to an electromagnetic relay and, more particularly to the supporting structure of a movable contact piece of the electromagnetic relay.

Description of the Prior Art

A conventional electromagnetic relay has been formed in such structure as illustrated, for example, in Figs. 23-25, wherein an iron core 1 provided with a permanent magnet 2 at the central part thereof to be generally in an E-shaped cross section is wound with a coil 3, thereby constituting an electromagnet block 4. The electromagnet block 4 is fixedly placed above a base (not shown), so that a protrusion 5a of a movable iron piece 5 is rotatably attracted to the lower surface of the permanent magnet 2. A movable contact piece 7 is integrally united with the central part at the lower surface of the movable iron piece 5 via an insulation bed 6. However, a predetermined gap is maintained between the iron piece 5 and movable contact piece 7. The movable contact piece 7 has movable contact points 7a, 7a at the lower surface of the opposite ends thereof. The movable contact points 7a, 7a confront to fixed contact points 8, 8 in a manner to be easily brought in or out of touch with the latter. Moreover, a hinge spring (not shown) extended sideways from the lateral side of the movable contact piece 7 is connected to a common terminal protruding from the upper surface of the base. Accordingly, the movable contact piece 7 is elastically supported, so that the movable contact piece 7 is rotatable around a point P2.
When the coil 3 is excited or demagnetized, the opposite ends of the movable iron piece 5 are alternately brought into or out of contact with confronting end parts of the iron core 1, thereby attracting or detaching the movable contact points 7a, 7a to or from the fixed contact points 8, 8 alternately.
In the above-described structure of the conventional electromagnetic relay, a contact point P1 between the lower surface of the permanent magnet 2 and the movable iron piece 5 is spaced a gap from the rotary point P2 of the movable contact piece 7, as mentioned earlier and indicated in Fig. 23. This gap not only interrupts smooth operation of the relay, but applies an excessive shearing stress to the hinge spring, resulting in easy fatigue and short lifetime of the relay.
If it is tried to turn the movable contact piece 7 around the contact point P1, it is displaced a distance λ in an extending direction thereof, thus causing an inconvenience to mount a pigtail or the like to the movable contact piece 7 for solving the displacement, and accordingly the relay results in complicated structure as a whole.
In the meantime, when the movable contact piece 7 is turned around the rotary point P2, the protrusion 5a of the movable iron piece 5 scrubs the lower surface of the permanent magnet 2, with generating abrasion dusts. In consequence, poor connection is easy to take place, and the operating characteristic of the relay is variously changed.
Such problems as mentioned hereinabove are noted also in the electromagnetic relay disclosed in Japanese Patent Laid-Open No. 59-44765 (44765/1984) wherein the movable iron piece 5 is rotatably supported by the electromagnet block 4 placed on a base 9 as shown in Fig. 26.

SUMMARY OF THE INVENTION

An essential object of the present invention is to provide an electromagnetic relay having smooth and difficult-to-change operating characteristic, long service life in a simple structure, without generating abrasion dusts.
A further object of the present invention is to provide an electromagnetic relay with high yield which enables the operating characteristic to be adjusted while the components are left as incorporated in the relay.
A still object of the present invention is to provide an electromagnetic relay with high yield which requires no particular assembling accuracy of components, but allows easy adjustment after assembling.
A yet further object of the present invention is to provide an electromagnetic relay without variations in the contacting strength of a hinge spring and operating characteristic, having high productivity.
A still further object of the present invention is to provide an electromagnetic relay which realizes high productivity, high assembling accuracy and high yield.
A yet object of the present invention is to provide an electromagnetic relay which allows a base to be easily fixed to an electromagnet block, thereby achieving a thin and compact-size structure.
In accomplishing the above-described objects, according to an electromagnetic relay of the present invention, a movable iron piece is rotatably supported at the central part on one surface thereof by an electromagnet block on a base, while the central part on the other surface of the iron piece is, with a predetermined gap maintained, integrally united with the central part of a movable contact piece via an insulation bed. At the same time, a part of a hinge spring extended from the central part of the lateral side of the movable contact piece is welded to a receiver part of a common terminal protruding from the upper surface of the base, so that the hinge spring is elastically supported. Accordingly, the movable contact piece is rotated by the movable iron piece which is driven as the electromagnet block is excited and demagnetized, thereby closing or opening contact points. The electromagnetic relay of the present invention in the above-described structure is characterized in that the rotary center of the movable iron piece is rendered generally on the same plane as that of the movable contact piece, removing a gap in an up-and-down direction observed in the conventional example. Accordingly, not only the smooth operating characteristic can be gained, but the hinge spring is prevented from being loaded with an excessive shearing stress although it is elastically supported. Thus, the lifetime of the hinge spring can be elongated. Moreover, since the movable contact piece is not displaced in an elongated direction, a pigtail or the like is not necessitated, so that the relay can be formed in a simple structure. Likewise, also the movable iron piece is not shifted in an elongated direction, and accordingly the movable iron piece never comes to scrub the permanent magnet, hardly generating abrasion dust. As a result of this, poor connection becomes hard to take place, and the operating characteristic of the relay is not easy to change.
According to one aspect of the present invention, a fixed contact point of a terminal provided in the base is opposed in a connectable manner to a movable contact point of the movable contact piece rotatably supported above the base. The movable contact piece is rotated consequent to the rotation of the movable iron piece as the electromagnet block is excited or demagnetized, thereby closing/opening contact points. More specifically, an end of the terminal where the fixed contact point is formed is projected sideways in an adjustable manner from the lateral face of the base. Accordingly, even if the inner components are kept installed on the upper surface of the base, the end part can be adjusted by an adjusting tool which can be easily insert ed. Therefore, it becomes possible to automatically adjust the operating characteristic of the relay, with the yield and adjusting efficiency remarkably improved. Furthermore, since the end part is projected, burrs and flashes generated when the base is molded are hardly adhered to the periphery of the fixed contact point, thereby making it easy to circulate a cleaning liquid. The fixed contact point can be cleaned with improved efficiency. In addition, the fixed contact point can be post-mounted to the end part, and therefore prevented from being broken when the terminal is insertion-molded in the base.
In a further aspect of the present invention, when the electromagnet block wherein a permanent magnet is arranged at the center of a generally U-shaped iron core is excited, the movable iron piece is turned like a seesaw, and simultaneously the movable contact piece integrally formed with the movable iron piece is driven, thereby to close/open the contact points. The hinge spring extended sideways from the central part of the movable contact piece is projected from the upper surface of the base and bent outwards, to be rigidly welded to the receiver part of the common terminal. Since the receiver part can be adjusted from the lateral side, the hinge spring can be bent by, e.g., twisting the receiver part after assembling, so that the load on the movable contact piece can be adjusted.
In a still aspect of the present invention, the welding part at the end of the hinge spring is welded to the terminal projecting from the upper surface of the base, whereby the movable contact piece is rotatably supported. A positioning arm extending from the welding part of the movable contact piece is fitted into a recessed part formed on the upper surface of the base. Accordingly, only by fitting the arm of the movable contact piece into the recessed part, the movable contact piece can be positioned at a position different from the welding part. Therefore, no troublesome work is necessary for positioning the movable contact piece, and moreover the arm is not melted even when the welding part of the hinge spring is integrally welded to the receiver part of the terminal, so that the welding part is never displaced, without varying the contacting strength or operating characteristic of the relay.
In a still further aspect of the present invention, the insulation bed having the movable contact piece insertion-molded and the movable iron piece are formed into one unit in an up-and-down direction. The block is driven by the movable iron piece which is rotated in accordance with the excitation and demagnetization of the electromagnet block, so that the movable contact point in the movable contact piece is brought into or out of contact with the fixed contact point. According to the present invention, the insulation bed of the block is integrally formed with the movable iron piece through a secondary insertion molding with the help of a synthetic resin, accordingly without requiring caulking operation or injecting/hardening opera tion of an adhesive. In consequence, the number of operating procedures is reduced, thereby improving the productivity. Moreover, since the movable contact piece block and movable iron piece are correctly positioned by means of a mold during the secondary insertion molding, the movable iron piece is not deviated in position. Thus, the assembling accuracy is improved and the relay is rid of variations of the operating characteristic. Further, the movable contact piece block is not necessary to be heated to harden the adhesive, and therefore the contact point is avoided from being exposed to high temperatures for a long time. Accordingly, dust, oil etc. is not baked or adhered to the contact point, whereby an inferior connection is not given rise to. The contacting reliability as well as the yield is improved.
In a yet further aspect of the electromagnetic relay of the present invention, the electromagnet block is integrally overlapped on the base. In this case, a solvent is injected into a gap between the resinous parts where the base and electromagnet block are engaged or in contact with each other, so that the electromagnet block is securely fixed to the base. For the solvent, such one that can dissolve the resinous parts of the base and electromagnet block is used. While the solvent tightly fixes the resinous parts of the base and electromagnet block, the solvent itself scatters in the air as a gas.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will become apparent from the following description taken in conjunction with preferred embodiments thereof with reference to the accompanying drawings, in which:

Fig. 1 is an exploded perspective view of an electromagnetic relay according to one preferred embodiment of the present invention;
Fig. 2 is a horizontal cross sectional view of Fig. 1;
Fig. 3 is a vertical cross sectional view of Fig. 1;
Fig. 4 is a right sectional view of Fig. 1;
Figs. 5 and 6 are plan views explanatory of the molding process of a base;
Fig. 7 is a plan view of a movable contact piece block in the electromagnetic relay;
Fig. 8 is a front elevational view of Fig. 7;
Fig. 9 is a bottom view of Fig. 7;
Fig. 10 is a right side elevational view of Fig. 7;
Fig. 11 is a plan view of a movable iron piece of the electromagnetic relay;
Fig. 12 is a front elevational view of Fig. 11;
Fig. 13 is a plan view of the movable contact piece block integrally formed with the movable iron piece;
Fig. 14 is a front elevational view, partially in cross section, of Fig. 13;
Fig. 15 is a bottom view of Fig. 13;
Fig. 16 is a right sectional view of Fig. 13;
Fig. 17 is a perspective view of the electromagnetic relay in the middle of the assembling process;
Fig. 18 is a graph indicating a load curve of the operating characteristic;
Figs. 19-21 are views explanatory of the operation of the electromagnetic relay;
Fig. 22 is an enlarged front elevational view of a welding part;
Fig. 23 is a schematic side elevational view of a conventional electromagnetic relay;
Figs. 24 and 25 are enlarged views of an essential part of Fig. 23; and
Fig. 26 is an enlarged sectional view of another conventional electromagnetic relay.

DESCRIPTION OF A PREFERRED EMBODIMENT

Before the description of the present invention proceeds, it is to be noted here that like parts are designated by like reference numerals throughout the accompanying drawings.
An electromagnetic relay according to one preferred embodiment of the present invention will be described in detail hereinbelow with reference to Figs. 1-22.
The electromagnetic relay of the present invention is substantially comprised of a base 10, a movable contact piece block 20, a movable iron piece 30, an electromagnet block 40, base reinforcing members 50,60, and a casing 70.
The base 10 is generally rectangular in a plan view. However, the central part at each short side of the base 10 is notched. Fixed contact terminals 11,12 and a common terminal 13 are mounted in the base 10 through insertion molding. There are four supporting members 14 projecting at four corners of the upper surface of the base 10 which have insertion holes 15,15,16,16 at respective base portions. Each supporting member 14 has an abutment portion 14a which abuts against the lower surface at the corner of a jaw 43b or 43c of the electromagnet block 40, an engagement portion 14b which extends in a perpendicular direction from the abutment portion 14a to be engaged with the side face at the corner of the jaw 43b or 43c, and a chamfered portion 14c formed in the engagement portion 14b.
A platform 17 with a positioning longitudinal groove 17a is projected at a position adjacent to the insertion hole 16 for a coil terminal of the base 10. Moreover, a receiver 13a for the common terminal 13 is protrudingly welded in the vicinity of the platform 17. An upper end of the receiver 13a is bent outwards, so that the receiver 13a can be adjusted from the lateral side. A fitting recess 18 formed at the center on the upper surface of the base 10 has a vent hole 18a at the center on the bottom surface thereof, and bench portions 18b,18b of a generally semi-circular cross section projecting in the vicinity of the opposite side edges thereof (although the bench portion at the front side is not shown in Fig. 1).
In molding the base 10, for example, terminals 11,12 for the fixed contact points and common terminal 13 which are integrally coupled in one unit by a hatched lead frame 80 and II-shaped coupling members 81,81 as shown in Figs. 5 and 6 are first formed through insertion molding. Then, the terminals 11,12,13 are separated from the lead frame and bent downwards, with the coupling members 81,81 cut off (with reference to Fig. 6), whereby adjusting tongue pieces 11b,12b are formed at front ends of the fixed terminals 11,12 equipped with fixed contact points 11a,12a, respectively. These tongue pieces 11b,12b are so projected as to be adjustable from the lateral side of the base 10, with having a small width, so that it is becomes easy to insert an adjusting tool.
The base 10 is cut and separated from the lead frame 80 after all the inner components are incorporated in the base and the operating characteristic is checked and adjusted.
It is needless to say here that the front ends of the fixed terminals 11,12 may be protruded from the lateral face of the base.
As is indicated in Figs. 7-10, the movable contact piece block 20 represents a line symmetry wherein the central parts of a pair of movable contact pieces 22,23 arranged in parallel are insertion-molded with an insulation bed 21. The insulation bed 21 is made of synthetic resin and is provided with through- holes 24,24 intended for a secondary molding at the central part thereof. Moreover, the insulation bed 21 is provided with supporting parts 25,25 projecting upwards at the confronting opposite side edges thereof.
Meanwhile, the movable contact pieces 22,23 are formed of a conductive thin plate through punching. Both ends of each movable contact piece 22 or 23 are divided into two, with movable contact points 22a,23a securely welded to the lower surface at the one end and movable contact points 22b,23b securely welded to the lower surface at the other end. Furthermore, the central part of a long side of each of the movable contact pieces 22,23 is extended sideways, bent upwards, to constitute a standing part 22c or 23c. A hinge spring 26 extending from an upper end of the standing part 22c or 23c is projected generally in parallel to an extending direction of the movable contact piece 22 or 23 from the supporting part 25 of the insulation bed 21. Moreover, a welding part 26a at the front end of the hinge spring 26 is bent' in a direction reverse to the above-referred projecting direction. A positioning arm 27 is found on an extension line of the welding part 26a.
Referring now to Figs. 11 and 12, the movable iron piece 30 is made of a generally rectangular plate in a plan view. The central part of the iron piece 30 is processed to have a swelling part 31. The movable iron piece 30 is turned around a fulcrum, namely, a ridge 31a. Through- holes 32,32 are formed for insertion molding, confronting to each other with the swelling part 31 interposed therebetween. At the same time, a magnet-shield plate 33 is attached to one end of the upper surface of the iron piece 30.
The movable iron piece 30 is, as shown in Figs. 13-16, positioned between the supporting parts 25,25 of the movable contact piece block 20, and the through- holes 32,32 of the movable iron piece 30 are overlapped to be aligned with the through- holes 24,24 of the insulation bed 21, thereby to communicate the through- holes 32,32 with 24,24. After this, a secondary insertion-molding is conducted to form a coupling body 34 in an U-shaped cross section. Thus, the movable contact piece block 20 is united with the movable iron piece 30.
What is noted in the present embodiment is that a synthetic resin is injected and solidified in a recessed portion 21a (referring to Fig. 14) formed at the lower surface of the insulation bed 21, whereby the movable contact piece block 20 can be restricted small in height and is difficult to rattle. If the coupling body 34 is formed in continuation to the insulation bed 21, it can avoid a waste of time, thereby improving the productivity. Particularly, if the movable contact pieces 22,23 are insertion-molded when they remain hoops, the productivity is further more improved.
The through-holes for the secondary insertion molding may be single.
After the movable contact piece block 20 is united with the movable iron piece 30, the insulation bed 21 of the block 20 is fitted in the fitting recess 18 of the base 10. At the same time, the positioning arm 27 of the hinge spring 26 is slided and fitted into the positioning longitudinal groove 17a of the base 10. Subsequent to the positioning, the welding part 26a of the hinge spring 26 is welded to the receiver 13a of the common terminal 13, so that the welding part 26a is arranged generally even with the ridge 31a of the movable iron piece 30.
In the meantime, the iron core 41 generally in an U-shaped cross section is changed to be E-shape since it is provided with a permanent magnet 42 at the central part thereof, as is clear from Figs. 19-21. The electromagnet block 40 is obtained by insertion-molding this iron core 41 with a spool 43. A magnetic electrode portion 42a of the permanent magnet 42 is exposed from the lower surface of the central jaw 43a of the spool 43, while a left magnetic electrode portion 41a of the iron core 41 is exposed from the lower surface of the jaw 43b of the spool 43. At the same time, the right magnetic electrode portion 41b of the iron core 41 is exposed from the lower surface of the jaw 43c of the spool 43. As shown in Fig. 17, coil terminals 44,44,45,45 are insertion-molded into the jaws 43b,43c. Moreover, a leading wire of a coil 46 wound around the spool 43 is tied to a tie-up portion 44a of the coil terminal 44.
The coil terminals 44,44,45,45 are inserted into respective coil terminal insertion holes 15,15,16,16, so that, as is understood from Figs. 17 and 22, the side face at the corner of each jaw 43b or 43c is engaged with the engagement portion 14b of the base 10, and the lower face at the corner thereof is brought to butt against the abutment portion 14a of the base 10. Thereafter, a solvent S is injected between the jaws 43b,43c and chamfered portion 14c from a direction shown by an arrow in Fig. 22. As the solvent S percolates into a gap between the jaws 43b,43c and engagement portion 14b and further between the jaws and abutment portion 14a because of the capillary phenomenon, those portions are melted and welded together, whereby the base 10 is tightly welded to the electromagnet block 40. On the other hand, the solvent itself is diffused in the air as a gas.
When the electromagnet block 40 is integrally formed with the base 10 in the manner as described hereinabove, the swelling part 31 of the movable iron piece 30 is attracted to the magnetic electrode portion 42a of the block 40, and the movable iron piece 30 is eventually kept in a turnable state. The turning center of the movable iron piece 30 is on the same plane as the turning center of the movable contact pieces 22,23.
The operating characteristic of the electromagnetic relay is checked at this stage. In case a predetermined operating characteristic is not obtained, the tongue pieces 11b,12b of the fixed terminals 11,12 protruding from the side face of the base 10 are twisted by an adjusting tool (not shown) so that straight parts at the opposite sides of the load curve S (referring to Fig. 18) are observed within a predetermined attraction force curve. In addition, the receiver 13a of the common terminal 13 projecting from the upper edge of the base 10 should be adjusted in the similar manner. More specifically, if the receiver 13a of the common terminal 13 is twisted in a direction (a) of Fig. 17(?), the load is changed in an (a) direction as indicated by a one-dot chain line in Fig. 18, with increasing the operating voltage. In contrast, if the receiver 13a is twisted in a direction (b), the load is changed in a (b) direction as indicated by a two-dot chain line in Fig. 18, lowering the operating voltage. Thus, the operating characteristic can be easily adjusted in the manner as above.
After the adjusting work is completed, the semimanufactured electromagnetic relay is separated from the lead frame 80 (referring to Fig. 17).
Each of the base reinforcing members 50,60 is in such a shape as is able to be fitted into the edge of the lower surface of the base 10. The base reinforcing members 50,60 have coil terminal holes 51,51 and 61,61 inserted into corresponding coil terminals 44,44 and 45,45 of the electromagnet block 40 which terminals are projected from the lower surface of the base 10. Further, recessed parts 52,52 and 62,62 of the reinforcing members 50,60 are fitted into positioning protrusions 10a,10a formed at the lower surface of the base 10 (although the positioning protrusions at the rear side are not shown in Fig. 1), respectively.
The box-like casing 70 is able to be fitted into the base 10. After the casing 70 is fitted into the base 10, a sealant 90 is injected and solidified into a recessed part 71 (Fig. 3) formed at the rear face of the base 10. The inner gas is extracted through the vent hole 18a. Thereafter, the vent hole 18a is thermally melted and closed. Accordingly, the electromagnetic relay is completely assembled.
Now, the operation of the electromagnetic relay in the above-described structure will be discussed hereinbelow.
In case without excitation, a right side end 30b of the movable iron piece 30 is attracted to the right magnetic electrode portion 41b of the iron core 41 by a magnetic flux generated by the permanent magnet 42 (shown by a dot line in Fig. 19), whereby the magnetic circuit is closed. Accordingly, the movable contact points 22a,23a of the movable contact pieces 22,23 are in touch with the fixed contact points 11a,11a, whereas the movable contact points 22b,23b are detached from the fixed contact points 12a,12a.
On the other hand, when the coil 46 is magnetized through application of a voltage thereto, and a magnetic flux (shown by a one-dot chain line in Fig. 20) which erases the above-mentioned magnetic flux by the permanent magnet 42 is generated, a left side end 30a of the movable iron piece 30 is attracted to the left magnetic electrode portion 41a of the iron core 41. Consequently, the movable iron piece 30 is turned around the ridge part 31a in spite of the magnetic force of the permanent magnet 42. As a result, the right side end 30b of the movable iron piece 30 is turned away from the right magnetic electrode portion 41b, and then, the left side end 30a of the movable iron piece 30 is brought in touch with the left magnetic electrode portion 41a of the iron core 41 (with reference to Fig. 21). The movable contact points 22a,23a of the movable contact pieces 22,23 are separated from the fixed contact points 11a,11a, and the movable contact points 22b,23b are turned into contact with the fixed contact points 12a,12a.
When the coil 46 is released from the above magnetized state, the movable iron piece 30 is returned to its original position by the restoring force, i.e., the spring force of the movable contact pieces 22,23 and hinge springs 26,26 as well as the imbalance of the magnetic force, etc. Accordingly, the movable contact points 22a,23a and 22b,23b are switched, so that the electromagnetic relay is returned to the original state.
Although the foregoing embodiment is related to the electromagnetic relay of a self-restoration type, the present invention is not restricted to the above type, but, an electromagnetic relay of a self-retention type is possible if the shape of the iron core 41 is changed and the spring force of the movable contact pieces 22,23 is adjusted.
Moreover, the structure of the electromagnetic relay is not limited to such as in the present embodiment. It is needless to say that any structure will be applicable so long as the electromagnet block is overlaid with the base or mounted on the base.
Instead of positioning the contact piece block 20 with the movable iron piece 30 between the base and electromagnet block 40, the integrated body of the contact piece block 20 and movable iron piece 30 may be positioned above the electromagnet block 40.
According to the present invention, the operating characteristic of the electromagnetic relay can be easily adjusted, for example, by twisting the receiver even after assembling the relay.
In addition, since the above receiver is bent outwards, the operating characteristic of the relay can be automatically adjusted from the lateral side.
What's better, the assembling accuracy and the accuracy of components as well are not strictly required since the post-adjustment is possible as mentioned above. Therefore, the electromagnetic relay of the present invention can be manufactured at low cost with good yield.
The base of the electromagnetic relay is rigidly secured to the electromagnet block in a simple manner using a solvent, with a few number of abutment portions and engagement portions, whereby the base and electromagnet block can be formed thin and compact in size. The cross sectional area of the coil can be increased without changing the outer size, so that the attracting force is enlarged.
Since it is not necessary to press in the terminals, no high accuracy is required for the terminals or terminal insertion holes. Therefore, the electromagnetic relay of the present invention can be assembled with much ease in a short time as compared with the case where each block or component is fixedly mounted by an adhesive.
An outgas is not generated after fixing the base with the electromagnet block, thus causing no erroneous operation of the electromagnetic relay resulting from an inferior connection or the like.
Although the present invention has been fully described by way of example with reference to the accompanying drawings, various changes and modifications would be apparent to those skilled in the art. Such changes and modifications should be construed as defined by the appended claims unless they depart from the scope of the present invention.

Claims

1. In an electromagnetic relay wherein a fixed contact point of a fixed contact point terminal provided in a base is opposed to a movable contact point of a movable contact piece supported in a rotatable manner above said base, so that said fixed contact point and said movable contact point is brought in and out of touch with each other by turning said movable contact piece by a movable iron piece driven in accordance with the excitation/demagnetization of an electromagnet block in said base, the improvement thereof characterized in that a front end of said fixed contact point terminal with said fixed contact point is projected sideways from the lateral side face of said base in an adjustable manner.

2. In an electromagnetic relay wherein the central part on one surface of a movable iron piece is supported in a rotatable manner by an electromagnet block in a base, while generally the central part of a movable contact piece is united via an insulation bed with the central part of the other surface of said movable iron piece with a predetermined gap, the improvement thereof characterized in that a welding part of a hinge spring extending from the central part of the lateral side of said movable contact piece is welded to a receiver part of a common terminal protruding from the upper surface of said base so that said hinge spring is elastically supported, whereby said movable contact piece is rotated by said movable iron piece which is rotated in accordance with the excitation/demagnetization of said electromagnet block thereby to open/close said contact points, further characterized in that the rotary center of said movable iron piece is arranged generally on the same plane with the rotary center of said movable contact piece.

3. In an electromagnetic relay wherein when an electromagnet block provided with a generally U-shaped iron core with a permanent magnet is magnetized, a movable iron piece is rotated like a seesaw around the part in the vicinity of said permanent magnet, and accordingly a movable contact piece integrated with said movable iron piece is driven, thereby to open/close contact points, the improvement thereof characterized in that a hinge spring extending sideways from the turning center of said movable contact piece is projected from the upper surface of a base, bent outwards, and rigidly welded to a receiver part of a common terminal which is so provided as to be adjustable from the lateral side.

4. In an electromagnetic relay wherein a welding part at the front end of a hinge spring extending from the central part of the lateral side of a movable contact piece is welded to a terminal projecting from the upper surface of a base, so that said movable contact piece is supported in a rotatable fashion, the improvement thereof characterized in that a positioning arm extending from said welding part of the movable contact piece can be positioned by being fitted into a positioning recess formed on the upper surface of said base.

5. In an electromagnetic relay wherein an insulation bed of a contact piece block having a movable contact piece insertion-molded is integrally formed with a movable iron piece in an up-and-down direction, and said movable contact piece block is driven by said movable iron piece rotated in accordance with the excitation/demagnetization of an electromagnet block thereby to bring a movable contact point formed in said movable contact piece into or out of contact with a fixed contact point, the improvement thereof characterized in that said insulation bed of the contact piece block is integrally formed with said movable iron piece through a secondary insertion molding.

6. An electromagnetic relay comprising an electromagnet block integrally overlapped with a base, and a solvent injected into a gap between resinous parts said base and electromagnet block being engaged or abut with each other.