EP3051564A1

EP3051564A1 - Contact point mechanism part and electromagnetic relay equipped with same

Info

Publication number: EP3051564A1
Application number: EP14838853.1A
Authority: EP
Inventors: Yuji Kozai; Hiroyasu Tanaka; Kei Takahashi; Sumihisa Kondo; Kazuya Soda; Kaori HAYASHIDA
Original assignee: Omron Corp; Omron Tateisi Electronics Co
Current assignee: Omron Corp
Priority date: 2013-09-27
Filing date: 2014-08-29
Publication date: 2016-08-03
Also published as: JP2015088463A; JP5720840B2; WO2015045738A1; BR112015004484A2; EP3051564A4; RU2015107537A; MX2015003167A; CN105103257B; CN105103257A

Abstract

Provided is a reliable contact mechanism which requires less driving force and therefore less power consumption for breaking contacts. The contact mechanism engages driving projection 43 on one of ends of sliding card 40 with a distal end of movable contact plate 60, slides the card 40 to rotate movable contact plate 60, and causes movable contact 56 on the movable contact plate 60 to make and break contacts with stationary contact 52. A driving projection 43 on one end of card 40 engages a returning elastic tongue 67c provided on the distal end of the plate 60 to make contacts with driving projection 43, when movable and stationary contacts 56, 52 are in in contact with each other.

Description

TECHNICAL FIELD

The present invention relates to a contact mechanism and, more particularly, to a contact mechanism to be assembled in a switching device such as an electromagnetic relay.

BACKGROUND

Conventionally, there has been disclosed, in Fig. 1 of Patent Document 1, a switching device such as an electromagnetic relay in which an armature 10 rotates back and forth in response to applications of voltage and thereby to an electromagnetic coil 8 to slidingly move an actuator 13 up and down, which in turn moves a contact spring 4 to make and break contacts between a contact button 6 and a second relay contact 3.
Patent Document 1: US Patent No. 6,661,319
According to the contact mechanism, the actuator 13 has a projection 15 in the form of bracket at its lower end to engage the contact spring 4 so that a breaking force is loaded evenly on substantially the entire transverse length of the contact spring. Then, when breaking the contacts, the movable contact plate 4 receives force acting only in a substantially vertical direction thereof, causing an increased load in the separation of the contacts, which needs the armature 10 to generate a greater driving force and, to this end, results in greater power consumption.
Considering those problems, an object of the present invention is to provide a contact mechanism which uses less power and driving force for making and breaking the contacts, and an electromagnetic relay with the contact mechanism.

SUMMARY OF THE INVENTION

According to one aspect of the invention, the contact mechanism for engaging a driving projection provided on one end of a card with a distal end of a movable contact plate and sliding the card to rotate the movable contact plate, causing a movable contact on the movable contact plate to connect with and disconnect from a stationary contact, comprises a driving projection disposed on one end side of the card, and a returning elastic tongue disposed on a distal end of the movable contact plate so as to make a contact with the driving projection, wherein the driving projection is configured to engage with the returning elastic tongue to cause a torsional moment on the movable contact plate while the movable contact moves away from the stationary contact.
According to this aspect of the invention, when breaking a contact, the driving projection of the card makes a contact with one longitudinal edge of the returning elastic tongue of the movable contact plate, causing a torsional force in the movable contact plate, which needs less force and therefore less energy consumption.
In another aspect of the invention, the contact mechanism may comprise a driving projection provided on a corner at one end of the card, and a returning elastic tongue extending in a longitudinal direction of the movable contact plate from at least one corner part on a distal end of thereof and provided so that it can make a contact with the driving projection, wherein the driving projection engages with the returning elastic tongue to cause a torsional moment on the movable contact plate as the movable contact moves away from the stationary contact.
According to this aspect of the invention, when breaking a contact, the driving projection of the card makes a contact with one longitudinal edge of the returning elastic tongue of the movable contact plate, causing a torsional force in the movable contact plate, which needs less force and therefore less energy consumption.
In another aspect of the invention, the contact mechanism may comprise a substantially L-shaped driving projection formed by projecting one corner of the movable contact plate to define a slit between the contact plate and the driving projection, and a returning elastic tongue projecting from at least one corner of a distal end of the movable contact plate and disposed in the slit so that it can make a contact with the driving projection, wherein the driving projection is configured to engage with the returning elastic tongue to cause a torsional moment on the movable contact plate as the movable contact moves away from the stationary contact.
According to this aspect of the invention, additionally the engagement of the returning elastic tongue in the slit prevents the returning elastic tongue from disengaging from the slit, which provides an enhanced reliability to the contact mechanism.
In another aspect of the invention, a movable contact may be provided on one side edge of the movable contact plate, and the driving projection may contact the returning elastic tongue extending from a distal end of the other side edge positioned on an opposite side to the one side edge.
According to this aspect of the invention, a longer moment arm is obtained, which increases the torsional moment to effectively prevent the contact fusing.
In another aspect of the invention, a pair of movable contacts may be arranged on a distal end of the movable contact plate so that they are spaced away from each other in a widthwise direction of the movable contact plate, and a pair of stationary contacts capable of making and breaking contacts with the movable contacts may be arranged so that they are spaced away from each other.
According to this aspect of the invention, a double contact structure is obtained, which provides an enhanced contact reliability to the contact mechanism.
To attain the object, an electromagnetic relay according to the invention comprises any one of the above contact mechanisms.
According to this aspect of the invention, when breaking a contact, the driving projection of the card makes a contact with one longitudinal edge of the returning elastic tongue of the movable contact plate, causing a torsional force in the movable contact plate, which needs less force and therefore less energy consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1A is a general perspective view showing an electromagnetic relay to which a first embodiment according to the present invention is applied and Fig. 1B is a general perspective view showing the electromagnet relay seen at a different angle.
Fig. 2 is an exploded perspective view showing the first embodiment illustrated in Fig. 1A.
Fig. 3 is an exploded perspective view showing the first embodiment illustrated in Fig. 1B.
Fig. 4 is a perspective view showing a state in which a cover is removed from Fig. 1A.
Fig. 5A is a sectional plan view of Fig. 4 and Fig. 5B is a partial enlarged perspective view of Fig. 4.
Fig. 6 is a perspective view showing a box-shaped base illustrated in Fig. 2.
Figs. 7A and 7B are a plan view and a sectional view showing a card illustrated in Fig. 2, respectively.
Fig. 8 is an exploded perspective view showing a movable contact plate illustrated in Fig. 2.
Figs. 9A and 9B are plan views showing states before and after an operation of the electromagnetic relay illustrated in Fig. 4.
Figs. 10A, 10B and 10C are front, rear and bottom views showing states before an operation of a contact mechanism illustrated in Fig. 2, respectively.
Figs. 11A, 11B and 11C are front, rear and bottom views showing states brought after the operation of the contact mechanism illustrated in Fig. 2, respectively.
Fig. 12 is a perspective view showing a state in which a cover is removed from an electromagnetic relay to which a second embodiment according to the present invention is applied.
Fig. 13 is an exploded perspective view showing the electromagnetic relay according to the second embodiment illustrated in Fig. 12.
Fig. 14 is an exploded perspective view showing the second embodiment illustrated in Fig. 13 as seen at a different angle.
Figs. 15A and 15B are plan views showing states before and after an operation of the electromagnetic relay illustrated in Fig. 12.
Figs. 16A, 16B and 16C are front, rear and bottom views showing states before an operation of a contact mechanism illustrated in Fig. 13, respectively.
Figs. 17A, 17B and 17C are front, rear and bottom views showing states brought after the operation of the contact mechanism illustrated in Fig. 13, respectively.
Fig. 18 is a perspective view showing a state in which a cover is removed from an electromagnetic relay to which a third embodiment according to the present invention is applied.
Fig. 19 is an exploded perspective view showing the electromagnetic relay according to the third embodiment illustrated in Fig. 18.
Fig. 20 is an exploded perspective view showing the third embodiment illustrated in Fig. 18 as seen at a different angle.
Fig. 21 is an exploded perspective view showing a movable contact terminal and a movable contact plate illustrated in Fig. 20.
Figs. 22A and 22B are enlarged perspective views showing a card illustrated in Figs. 19 and 20.
Figs. 23A and 23B are enlarged perspective view showing a rotating block illustrated in Figs. 19 and 20.
Figs. 24A and 24B are a schematic front view and a schematic bottom view showing states before an operation of a contact mechanism illustrated in Fig. 18.
Figs. 25A and 25B are a schematic front view and a schematic bottom view showing states brought after the operation of the contact mechanism illustrated in Fig. 18.

PREFERRED EMBODIMENTS OF THE INVENTION

With reference to Figs. 1A to 17C, an electromagnetic relay according to an embodiment of the invention will be described.
As shown in Figs. 1A to 11B, an electromagnetic relay according to a first embodiment of the invention includes a box-shaped base 10, an electromagnet block 20, a rotating block 30, a card 40, a contact mechanism 50, a support plate 70 and a cover 80.
As shown in Fig. 6, the base 10, which is configured to be a rectangular thin box, has an interior separated by an insulating wall 11 into first and second cavities 12 and 13. The insulating wall 11 has a cutout 11a defined therein. The rectangular base 1 has vertical shallow grooves 14a formed in its external side surfaces. The grooves 14a accept engaging portions 14b formed in and projected from the bottom surfaces thereof.
The first cavity 12 has a bearing 16 provided on a bottom surface thereof for supporting a rotating shaft 34a of the rotating block 30 which will be described below. Positioning concaves 17a and 17b are provided on opposite sides of the bearing 16 for positioning the electromagnet block 20 which will be described below. A concave cutout 18 is provided on an opening edge of the first cavity 12 for positioning a spool 21 of the electromagnet block 20 which will be descried below.
Terminal grooves 15a and 15b are formed on an open edge of the second cavity 13 for receiving stationary and movable contact terminals 51 and 54 of the contact mechanism 50 which will be described below.
As shown in Fig. 2, the electromagnet block 20 has a spool 21 with opposite flanges 22a and 22b, a coil 23 wound around the spool 21, an iron core 24 (Fig. 5A) inserted in a through-hole 22c formed in the spool 21, and yokes 25 and 27 fixed on the opposite ends of the iron core 24 projecting from the opposite flanges. Each of the yokes 25 and 27 is made of a T-shaped, punched magnetic plate with transversely extended wide portions 26 and 28, which is then right angled to have an L-shaped configuration. A pair of coil terminals 29 are press inserted in the terminal holes formed in the flange 22a of the spool 21. The opposite ends of the coil 23 are engaged around the respective coil terminals 29 and then soldered.
Five terminal holes may be formed in parallel in the flange 22a, allowing more coil terminals 29 and/or various arrangements of the coil terminals 29 to be selected as necessary. The coil terminals 29 are not limited to a straight rod-like terminal, and it maybe have another configuration such as T-configuration.
As shown in Fig. 5A, the rotating block 30 has a rotating block body 33. The rotating block body 33 , which has a permanent magnet 30a and a pair of movable iron plates 31 and 32 provided on opposite sides of the permanent magnet 30a, is made by insert molding. As shown in Fig. 2, the rotating block body 33 has a pair of rotating shafts 34a and 34b coaxially projecting from the opposite upper and lower surfaces of the block body 33 and a driving arm 35 integrally mounted on a side surface of the block body 33. The driving arm 35 has an engaging nail 36 formed on a distal end thereof.
As shown in Figs. 7A and 7B, the card 40 has a driving hole 41 provided on one side and an engaging hole 42 provided on the other side. A downwardly extending driving projection 43 is provided in one side corner of the card 40. A fail safe projection 45 is provided adjacent the driving hole 41. The driving projection 43 is configured so that it makes contacts with the longitudinal edge of movable contact plate 60 to cause a torsional moment acting thereon.
As shown in Fig. 2, the contact mechanism 50 has a stationary contact terminal 51 and a movable contact terminal 54.
As shown in Fig. 3, the stationary contact 52 is fixed to one end corner of the stationary contact terminal 51. As shown in Fig. 2, the movable contact terminal 54 supports the movable contact plate 60 fixed to one side thereof and has an operating hole 55 provided on the other side.
As shown in Fig. 8, the movable contact plate 60, which is made of three - first, second and third - conductive thin plate springs 61, 65 and 67 stacked one on top the other, has a movable contact 56 integrally fixed in a distal, one side portion of the plate.
The first conductive thin plate spring 61 has a spring constant adjusting slit 62a extending in a longitudinal direction from the proximal to distal end thereof and a substantially U-shaped fold 63a provided in its mid-portion so as to accommodate its deformation and then ensure a desired operating characteristic thereof. The distal end of the spring 61 is forked into three prongs including a central driving elastic tongue 64a and two reinforcing elastic tongues 64b and 64c provided on opposite sides of the central tongue.
The second conductive thin plate spring 65 has a spring constant adjusting slit 62b extending in a longitudinal direction from the proximal to distal end thereof and a substantially U-shaped fold 63a provided in its mid-portion so as to accommodate its deformation and then ensure a desired operating characteristic thereof. The second conductive thin plate spring 65 has an engaging cutout 66a formed in a distal, central portion thereof and two prongs provided on opposite sides of the cutout 66a. The prongs have opposing inner edges thereof which are right angled in the same direction to form position regulating elastic tongues 66b and 66c.
The third conductive thin plate spring 67 has a substantially U-shaped fold 63c provided in its mid-portion so as to accommodate its deformation and then ensure a desired operating characteristic thereof. The distal end of the spring 67 is forked into three prongs including a central driving elastic tongue 64a and two reinforcing elastic tongues which are right angled to form a position regulating elastic tongue 67a and a pair of returning elastic tongues 67b and 67c.
The spring constants of the first and second conductive thin plate springs 61 and 65 can be adjusted by changing the widths and/or lengths of the spring constant adjusting slits 62a and 62b. This facilitates the adjustment of the spring loads at making and breaking operations of the contacts, enhancing the design flexibility of the relay.
As shown in Fig. 4, the support plate 70 has both ends engaged and supported on the opposing opening edges of the base 10. As shown in Fig. 2, the rotating shaft 34b of the rotating block 30 is fitted in the bearing hole 71 formed at the center of the plate 70. Also, the ends 26b and 28b of the wide portions 26 and 28 of the yoke 25 and 27 are fitted in the positioning rectangular holes 72. This causes that the electromagnet block 20 and the rotating block 30 are positioned precisely.
The cover 80 takes a rectangular configuration capable of covering the opening of the base 10, and has an elastic engaging portions 81 extending from respective outer peripheral edges thereof.
Description will be made to an assembling of the electromagnetic relay.
As shown in Figs. 2 and 5, the electromagnet block 20 is positioned in the first cavity 12 of the base 10 (Fig. 6) with one ends 26a and 28a of the wide portions 26 and 28 of the yokes 25 and 27 fitted in the positioning concaves 17a and 17b on the bottom surface of the first cavity 12 and also with the flange 22a engaged in the cutout 18 of the base 10. According to the embodiment, the electromagnet block 20 is positioned in the base 10 at several portions, which is advantageous that it is precisely assembled in the base. Then, the stationary contact terminal 51 is fitted and positioned in the groove 15a of the second cavity 13.
As shown in Fig. 5, the card 40 is inserted in the operating hole 55 of the movable contact terminal 54 and is thus assembled into the movable contact plate 60 fixed to the movable contact terminal 54. For convenience of description, the movable contact terminal 54 is not shown in Fig. 5B.
Specifically, as shown in Fig. 5B, the driving elastic tongue 64a of the first conductive thin plate spring 61 is inserted in the driving hole 41 of the card 40. The card 40 is positioned or held by engaging the position regulating elastic tongues 66b and 66c of the second conductive thin plate spring 65 on the opposite side surfaces of the card 40. Also, the position regulating elastic tongue 67a of the third conductive thin plate spring 67 is engaged on one end of the card 40, and the returning elastic tongues 67b and 67c are engaged on the driving projections 43 and 44 of the card 40 (Fig. 10C) for the vertical positioning of the card. Further, the engaging nail 36 of the rotating block 30 is engaged in the engaging hole 42 of the card 40 (Fig. 5) and then the card 40 is inserted in the base 10. Thereafter, the card 40 is inserted in the operating cutout 11a of the insulating wall 11 of the base 10, and the movable contact terminal 54 is press fitted and thereby positioned in the terminal groove 15b. Subsequently, the rotating shaft 34a of the rotating block 30 is fitted in the bearing 16 of the base 10 to rotatably support the rotating block 30.
Furthermore, the opposite ends of the support plate 70 are engaged and supported on the opening edges of the base 10, and the rotating shaft 34b of the rotating block 30 is fitted in the bearing hole 71. Also, the other ends 26b and 28b of the wide portions 26 and 28 in the yokes 25 and 27 are fitted and positioned in the positioning rectangular holes 72 and 72g. Therefore, the electromagnet block 20 and the rotating block 30 are precisely positioned in the base 10, which results in a stable operating characteristic.
Finally, the cover 80 is positioned to cover the opening portion of the base 10, and the elastic engaging portion 81 of the cover 80 is engaged with the engaging portion of the base 10, which completes the assembling of the relay.
An operation of this present embodiment will be described below.
As shown in Fig. 9A, in the rotating block 30, the end 32a of the movable iron plate 32 is attracted to the wide portion 26 of the yoke 25 and the other end 31b of the movable iron plate 31 is attracted to the wide portion 28 of the yoke 27 by the magnetic force of the permanent magnet (not shown) . This causes that the movable contact plate 60 is attracted toward the movable contact terminal 54 against a spring force thereof through the card 40, which results in that the movable contact 56 is disconnected from the stationary contact 52. For convenience of description, the support plate 70 is not shown in Figs. 9A and 9B.
A voltage is applied to the coil 23 to generate a magnetic force in a direction which overcomes the magnetic force of the permanent magnet in the rotating block 30. This allows that one end 31a of the movable iron plate 31 of the rotating block 30 is attracted to the wide portion 26 of the yoke 25 and the other end 32b of the movable iron plate 32 of the rotating block 30 is attracted to the wide portion 28 of the yoke 27 so that the rotating block 30 is rotated. This allows the driving arm 35 to force the card 40, causing the spring force of the movable contact plate 60 to act on the card 40 through the driving elastic tongue 64a, which slidingly moves the card 40 toward the stationary contact terminal 51. As a result, the movable contact plate 60 is moved away from the movable contact terminal 54 by its spring force so that the movable contact 56 is brought into contact with the stationary contact 52. Subsequently, the one end 31a of the movable iron plate 31 of the rotating block 30 is attracted to the wide portion 26 of the yoke 25, and the other end 32b of the movable iron plate 32 is attracted to the wide portion 28 of the yoke 27. This allows that, even if the application of the voltage to the coil 23 is halted, the card 40 is immovably fixed by the magnetic force of the permanent magnet so that the connection between the movable contact 56 and the stationary contact 52 is maintained. In this state, the driving projection 43 and the returning elastic tongue 67b are disconnected from each other.
When a voltage is applied to the coil 23 in the opposite direction, the end 32a of the movable iron plate 32 is attracted to the wide portion 26 of the yoke 25, and the other end 31b of the movable iron plate 31 is attracted to the wide portion 28 of the yoke 27, causing the rotating block 30 to rotate in the opposite direction, which results in that the card 40 is pulled by the engaging nail 36 of the rotating block 30 to slidingly move away from the stationary contact terminal 51. This in turn causes that the driving projection 43 makes a contact with the returning elastic tongue 67b of the third conductive thin plate spring 67. Specifically, during the breaking of the contact between the movable and the stationary contacts 56 and 52, the driving projection 43 of the card 40 makes a contact at the one longitudinal edge of the movable contact plate 60, acting not only a separating force but also a torsional force or moment on the third conductive thin plate spring 67 so that the movable contact 56 is positively disconnected from the stationary contact 52. In particular, the driving projection 43 engages at one longitudinal edge away from the stationary contact 52 with a long moment, causing an increased torsional moment, which eases the disconnection between fused, be that as they may, movable and stationary contacts 56 and 52.
As shown in Figs. 12 to 17A-17C, the second embodiment of the invention is substantially the same as the first embodiment except that, as shown in Fig. 13, the movable contacts 56 and 57 are securely mounted on opposite sides of the distal end of the movable contact plate 60 and, correspondingly as shown in Fig. 14, the stationary contacts 52 and 53 are securely mounted on opposite sides of the stationary contact terminal 51 in parallel in the width direction, so that as shown in Figs. 15A-15B to 17A-17C the movable contacts 56 and 57 oppose the stationary contacts 52 and 53 to make connections therebetween.
Because other structures are substantially the same as the corresponding structures of the first embodiment, like parts are designated by like reference numerals and duplicate descriptions are eliminated.
An operation according to the second embodiment is substantially the same as that in the first embodiment. When an electromagnet block 20 is activated to rotate a rotating block 30 and thereby sliding a card 40, the movable contacts 56 and 57 simultaneously contact the stationary contacts 52 and 53 through the first conductive thin plate spring 61. Even if the voltage application to the coil 23 of the electromagnet block 20 is halted, the card 40 is held in its active position due to the magnetic force of the permanent magnet and then the connection between the movable contacts 56 and 57 and the stationary contacts 52 and 53 is maintained.
When the voltage is applied to the coil 23 of the electromagnet block 20 in the opposite direction, the rotating block 30 is rotated in the opposite direction so that the card 40 is slidingly moved in the opposite direction through the engaging nail 36 of the rotating block 30. This results in that the driving projection 43 of the card 40 contacts the returning elastic tongue 67c of the third conductive thin plate spring 67 to generate a torsional moment in the movable contact plate 60. This means that not only the separation force but also the torsional force is applied to the third conductive thin plate spring 67. As a result, the movable contact 57 is disconnected from the stationary contact 53 and then the movable contact 56 is disconnected from the stationary contact 52, which eases the disconnection between fused, be that as they may, movable and stationary contacts 56, 57 and 52, 53.
As shown in Figs. 12 to 25A-25B, the third embodiment of the invention, which is substantially the same as the first embodiment, has the base 10, electromagnet block 20, rotating block 30, card 40, contact mechanism 50, support plate 70 and cover 80. Like parts are designated by like reference numerals. Descriptions will be made only to the major differences below in detail.
As shown in Fig. 19, the base 10 is substantially the same as that in the first embodiment except that a bottom surface of the first cavity 12 has a pair of positioning projections 10a provided on a bottom surface of a first cavity 12 with a positioning hole 10b formed therein. For convenience of description, one of the positioning projections on one side is not indicated in the drawing. Also, the base 10 has attaching holes 19 at diagonally opposing corners thereof.
The electromagnet block 20 has a spool 21 with opposite flanges 22a and 22b. Two wires are wound around the spool and soldered at their ends to three coil terminals 29 press-fitted in the flange 22a. Specifically, one ends of the wires are connected to respective terminals and the other ends of the wires are connected to the common terminal. The block further has an iron core 24 inserted in the spool 21 and substantially L-shaped yokes 25 and 27 fixed to the opposite ends of the iron core 24 projecting from the spool. The yokes 25 and 27 terminate at distal ends thereof which function as magnetic pole portions 25a and 27a.
As shown in Fig. 23, the rotating block 30 has a block body 33 in which a permanent magnet 30a (not shown) and a pair of movable iron plates 31 and 32 are integrally mounted. The block body 33 has coaxially positioned rotating shafts 34a and 34b projecting from the upper and lower surfaces thereof. Also, a driving arm 35 is formed integrally on a side surface of the rotating block body 33. The driving arm 35 has an engaging nail 36 formed on a distal end portion thereof.
As shown in Figs. 22A and 22B, the card 40 has an engaging hole 42 formed on one side thereof, and a substantially L-shaped driving projection 43 formed on the lower end of the other side to form a slit 46. The driving projection 43 is configured so that it makes a contact at the longitudinal edge of the movable contact plate 60 to cause a torsional force or moment as described below. The driving projection 43 has a pair of upper and lower position regulating projections 47 formed on one side surface thereof.
As shown in Figs. 19 and 20, the contact mechanism 50 has a stationary contact terminal 51 and a movable contact terminal 54.
As shown in Fig. 19, the stationary contact terminal 51 has a stationary contact 52 fixed at one end side thereof. The movable contact terminal 54 has a movable contact plate 60 fixed at one end thereof and an operating slit 55a formed on a lower end thereof.
As shown in Fig. 21, the movable contact plate 60 has a structure in which four -first, second, third and fourth-conductive thin plate springs 61, 65, 67 and 68 are stacked one on top the other, and has a movable contact 56 integrally fixed to distal, one side end thereof.
The first conductive thin plate spring 61 has a slit extending from its distal end toward its proximal end to form two divided pieces 61a and 61b extending in parallel in its longitudinal direction. The divided pieces 61a and 61b have substantially U-shaped fold 63a formed in its mid-portion so as to accommodate its deformation and then ensure a desired operating characteristic thereof. The divided pieces 61a and 61b have semicircular slits in the distal end portions thereof to form thereinside elastically deformable bent portions 61c and 61d. The movable contact 56 is fixed to the bent portion 61c. This allows the contact force of the contact to be adjusted.
The second conductive thin plate spring 65 has a slit extending from its distal end toward its proximal end to form two divided pieces 61a and 61b extending in parallel in its longitudinal direction. The divided pieces 65a and 65b have substantially U-shaped fold 63b formed in its mid-portion so as to accommodate its deformation and then ensure a desired operating characteristic thereof. The movable contact 56 is fixed to the divided piece 65a.
The third conductive thin plate spring 67 has a slit extending from its distal end toward its proximal end to form two divided pieces 67d and 67e extending in parallel in its longitudinal direction. The divided pieces 67d and 67e have substantially U-shaped fold 63c formed in its mid-portion so as to accommodate its deformation and then ensure a desired operating characteristic thereof. The movable contact 56 is fixed to the divided piece 67d.
The fourth conductive thin plate spring 68 has substantially U-shaped fold 63d formed in its mid-portion so as to accommodate its deformation and then ensure a desired operating characteristic thereof. The distal end of the fourth conductive thin plate spring 68 is bent in the same direction to form upper returning elastic tongue 68a and lower position regulating elastic tongue 68b capable of engaging with the driving projection 43. Also, the returning elastic tongue 68a has upper and lower position regulating ribs 68c formed by bending distal ends thereof. The movable contact 56 is fixed to the distal end of the fourth conductive thin plate spring 68.
Each of the first, second and third conductive thin plate springs 61, 65 and 67 has two divided prongs so that it can be used in another electromagnetic relay devices, however, it is not needed to be divided into pieces. Also, the bent portions 61c and 61d of the first conductive thin plate spring 61 may be eliminated.
As shown in Figs. 19 and 20, the support plate 70 has a bearing hole 71 formed on a central portion thereof and downwardly projecting positioning projections 73 and 74 formed on the bottom surface thereof. The projections 73 and 74 have different diameters to prevent erroneous insertions thereof. The support plate 70 is supported on the base and positioned in a precise manner by engaging the rotating shaft 34b of the rotating block 30 in the central bearing hole 71 and press-fitting the positioning projections 73 and 74 in the positioning holes 10b of the positioning projections 10a of the base 10.
The cover 80, which has a rectangular configuration capable of covering an opening portion of the base 10, includes elastic engaging portions 81 downwardly extending from outer peripheral edges thereof, and an attaching cylindrical portions 82 projecting from the diagonal corners of the lower surface thereof. The cylindrical portions 82 have respective through holes 82a formed therein.
Description will be made to the assembling of the electromagnetic relay.
First, as shown in Fig. 19, the magnetic pole portions 25a and 27a of the yokes 25 and 27 are engaged and positioned in the corresponding positioning projections 10a on the bottom surface of the base 10 (the positioning projection 10a on this side is not shown). In the embodiment, the electromagnet block 20 of the base 10 is positioned precisely because it is positioned at several portions thereof. The stationary contact terminal 51 is press fitted and positioned in the terminal groove 15a adjacent the second cavity 13.
The engaging nail 36 of the rotating block 30 is engaged in the engaging hole 42 of the card 40. The card 40 is then inserted and positioned in the base 10, together with block 30. Also, the card 40 is engaged in the cutout 11a of the insulating wall 11 of the base 10. Further, the movable contact terminal 54 is press fitted and positioned in the terminal groove 15b with the movable contact plate 60 elastically deformed and inserted in the slit 46 of the positioned card 40. For this purpose, the position regulating ribs 68c and 68c are elastically engaged between the position regulating projections 47 of the driving projection 43 of the card 40. The returning elastic tongue 68a and the position regulating elastic tongue 68b hold the driving projection 43 therebetween. This causes that the distal end of the first conductive thin plate spring 61 makes a pressure contact with the inside surface of the slit 46 of the card 40 to force the card 40 toward the movable contact terminal 54. According to this embodiment, the movable contact plate 60 is assembled into the card 40 through the slit 46 of the card 40 by a single operation, increasing the productivity of the relay.
Further, the positioning projections 73 and 74 of the support plate 70 are press fitted in and supported at the positioning holes 10b of the positioning projections 10a of the base 10, and the rotating shaft 34b of the rotating block 30 is fitted in the bearing hole 71. This causes that the electromagnet block 20 and the rotating block 30 are positioned precisely into the base 10, which results in a stable operating characteristic.
Finally, the cover 80 is positioned to cover the opening of the base 10 with the attaching cylindrical portions 82 and 82 fitted in the attaching holes 19 and 19 of the base 10, respectively, and then the elastic engaging portion 81 of the cover 80 is engaged with the engaging portion of the base 10, which completes the assembling of the relay.
According to the present embodiment, all of the components are sequentially assembled from above into the base 10, which facilitates the assembling of relay with a high productivity.
An operation of the electromagnetic relay will be described below.
As shown in Fig. 24, the end 32a of the movable iron plate 32 of the rotating block 30 is attracted to the magnetic pole portion 25a of the yoke 25, and the other end 31b of the movable iron plate 31 is attracted to the magnetic pole portion 27a of the yoke 27, by a magnetic force of a permanent magnet (not shown), forcing the movable contact plate 60 toward the movable contact terminal 54 against the spring force thereof through the card 40, which results in that the movable contact 56 is disconnected away from the stationary contact 52. For convenience of description, the support plate 70 is not shown in Figs. 24 and 25.
A voltage is applied to the coil 23 to generate a magnetic force overcome the magnetic force of the permanent magnet of the rotating block 30, causing that one end 31a of the movable iron plate 31 of the rotating block 30 is attracted to the magnetic pole portion 25a of the yoke 25 and the other end 32b of the movable iron plate 32 in the rotating block 30 is attracted to the magnetic pole portion 27a of the yoke 27 to rotate the rotating block 30. This causes that the driving arm 35 presses the card 40 to slidingly move the card 40 toward the stationary contact terminal 51 and that the card 40 acts on the first conductive thin plate spring 61 of the movable contact plate 60. As a result, the movable contact plate 60 is rotated to move away from the movable contact terminal 54 so that the movable contact 56 is brought into contact with the stationary contact 52. Subsequently, one end 31a of the movable iron plate 31 of the rotating block 30 is attracted to the magnetic pole portion 25a of the yoke 25 and, furthermore, the other end 32b of the movable iron plate 32 is attracted to the magnetic pole portion 27a of the yoke 27 (Fig. 25). This ensures that, even if the application of the voltage to the coil 23 is halted, the position of the card 40 is held in position by the magnetic force of the permanent magnet, holding the connection between the movable contact 56 and the stationary contact 52. It should be noted, however, that the driving projection 43 is out of pressure contact with the distal end of the fourth conductive thin plate spring 68.
When a voltage is applied to the coil 23 in the opposite direction, one end 32a of the movable iron plate 32 is attracted to the magnetic pole portion 25a of the yoke 25 and the other end 31b of the movable iron plate 31 is attracted to the magnetic pole portion 27a of the yoke 27, rotating the rotating block 30 in the opposite direction so that the card 40 is slidingly moved by the engaging nail 36 of the rotating block 30 to disengage from the stationary contact terminal 51. During this motion, the driving projection 43 contacts the proximal portion of the returning elastic tongue 68a of the fourth conductive thin plate spring 68. This results in that the driving projection 43 of the card 40 engages the longitudinal one edge of the movable contact plate 60 at the disconnection between the movable and stationary contacts 56 and 52. This results in that not only a separating force but also a torsional force or moment acts on the fourth conductive thin plate spring 68 so that the movable contact 56 is positively disconnected from the stationary contact 52. In particular, the driving projection 43 engages at one longitudinal edge away from the stationary contact 52 with a long moment arm, causing an increased torsional moment, which eases the disconnection between fused, be that as they may, movable and stationary contacts 56 and 52.
The electromagnetic relay according to the invention is not limited to that described above, and the invention can be applied to various electromagnetic relays and electronic devices.

PARTS LIST

10: box-shaped base
10a: positioning projection
10b: positioning hole
11: insulating wall
11a: cutout
12: first cavity
13: second cavity
15a, 15b: terminal groove
16: bearing
17a, 17b: positioning concave
18: cutout
19: attaching hole
20: electromagnet block
21: spool
22a, 22b: flange
23: coil
24: iron core
25, 27: yoke
26, 28: wide portion
29: coil terminal
30: rotating block
31, 32: movable iron plate
33: block body
34a, 34b: rotating shaft
35: driving arm
36: engaging nail
40: card
41: driving hole
42: engaging hole
43: driving projection
45: fail safe projection
46: slit
50: contact mechanism
51: stationary contact terminal
52, 53: stationary contact
54: movable contact terminal
55: operating hole
56, 57: movable contact
60: movable contact plate
61: first conductive thin plate spring
62a, 62b: spring constant adjusting slit
63a, 63b, 63c: fold
64a: driving elastic tongue
64b, 64c: reinforcing elastic tongue
65: second conductive thin plate spring
66b, 66c: position regulating elastic tongue
67: third conductive thin plate spring
67a: position regulating elastic tongue
67b, 67c: returning elastic tongue
67d, 67e: divided piece
68: fourth conducting thin plate spring
68a: returning elastic tongue
68b: position regulating elastic tongue
68c: position regulating rib
70: support plate
71: bearing hole
72: positioning rectangular hole
73, 74: positioning projection
80: cover
81: elastic engaging portion
82: attaching cylindrical portion

Claims

A contact mechanism for engaging a driving projection provided on one end of a slidable card with a distal end of a movable contact plate and sliding the card to rotate the movable contact plate, causing a movable contact on the movable contact plate to connect with and disconnect from a stationary contact, the contact mechanism comprising:
a driving projection disposed on one end side of the card; and

a returning elastic tongue disposed on a distal end of the movable contact plate so as to make a contact with the driving projection,

wherein the driving projection is configured to engage with the returning elastic tongue to cause a torsional moment on the movable contact plate as the movable contact moves away from the stationary contact.
The contact mechanism according to claim 1, further comprising:
a driving projection provided on a corner at one end of the card; and

a returning elastic tongue extending in a longitudinal direction of the movable contact plate from at least one corner part on a distal end of thereof and provided so that it can make a contact with the driving projection;

wherein the driving projection is configured to engage with the returning elastic tongue to cause a torsional moment on the movable contact plate while the movable contact moves away from the stationary contact.
The contact mechanism according to claim 1, further comprising:
a substantially L-shaped driving projection formed by projecting one corner of the movable contact plate to define a slit between the contact plate and the driving projection; and

a returning elastic tongue projecting from at least one corner of a distal end of the movable contact plate and disposed in the slit so that it can make a contact with the driving projection,

wherein the driving projection is configured to engage with the returning elastic tongue to cause a torsional moment on the movable contact plate as the movable contact moves away from the stationary contact.
The contact mechanism according to any of claims 1 to 3, wherein a movable contact is provided on one side edge of the movable contact plate, and the driving projection contacts the returning elastic tongue extending from a distal end of the other side edge positioned on an opposite side to the one side edge.
The contact mechanism according to any of claims 1 to 4, wherein a pair of movable contacts is arranged on a distal end of the movable contact plate so that they are spaced away from each other in a widthwise direction of the movable contact plate, and a pair of stationary contacts capable of making and breaking contacts with the movable contacts are arranged so that they are spaced away from each other.
An electromagnetic relay comprising the contact mechanism according to any of claims 1 to 5.