Electromagnetic relay with pivotable armature

• US 4,825,179 A
• Filed: 03/11/1988
• Issued: 04/25/1989
• Est. Priority Date: 03/20/1987
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Works Ltd (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Works Ltd (Panasonic Holdings Corporation)
• Inventors: Shiomi, Masayuki, Nagamoto, Mitsuki
• Primary Examiner(s): Goldberg, E. A.
• Assistant Examiner(s): Donovan, Lincoln
• Application Number:
  US07/167,281
• Time in Patent Office: 410 Days
• Field of Search: 335/78-85, 335/128, 335/129, 335/130, 335/131
• US Class Current: 335/80
• CPC Class Codes: H01H 50/026 Details concerning isolation between driving and switching circuit
• CPC Class Codes: H01H 50/26 Parts movable about a knife edge
• CPC Class Codes: H01H 50/641 intermediate part performing a rectilinear movement H01H50/645, H01H50/66 - H01H50/74 take precedence

Abstract

A relay has a contact assembly and an electromagnet with a L-shaped pivotable armature rockable with its inside angle supported against a complementary yoke edge. A base mounting the electromagnet and the contact assembly is formed with a retainer rib which is opposed to the yoke edge so as to loosely engage the angled portion of the armature therebetween but to prevent the inside angle of the armature from departing beyond an allowable distance from the yoke edge. A movable spring included in the contact assembly is operatively connected to a first leg of the L-shaped armature so as to be driven thereby to close the contacts in response to the energization of the electromagnet. The armature in the reset position has its free end rest on a fulcrum projection on the base and receives a return bias from the movable spring at a point inwardly of the fulcrum projection such that the return bias of the movable spring acts as a torque which causes the armature within the allowable distance from the yoke edge to pivot about the fulcrum in a direction of urging the inside angle of the armature toward the yoke edge to such an extent that, upon energization of the electromagnet, the inside angle of the armature can be firstly attracted to the yoke edge into exact coincidence therewith, ensuring an accurate pivotal movement about the yoke edge without requiring a conventional retainer spring which constantly urges the inside angle to the yoke edge.

Claims

1. In an electromagnetic relay comprising:

a base mounting an electromagnet and a contact assembly;

said contact assembly comprising a fixed contact on said base and an elongated movable spring carrying at its one end a movable contact engageable with said fixed contact and supported at the other end to said base;

said electromagnet including a core having first and second ends, a coil wound about said core, a yoke connected at its one end to the first end of the core and extending parallel to said core, and a generally L-shaped armature having a first leg extending along the yoke and a second leg extending over the second end of said core to define therebetween an air gap;

said armature rockable with its inside angle pivotally supported against an edge at the other end of said yoke for pivotal movement in response to the energization and deenergization of said coil between an attracted position in which the second armature leg is attracted to said second end of the core and a reset position in which the second armature leg is spaced away from the first end of said core;

said first armature leg being operatively connected to said movable spring through an electrically insulative actuator so as to drive the movable spring in a direction of engaging the movable contact with said fixed contact against a return bias applied to the armature as said armature moves to its attracted position in response to the energization of said coil, said return bias causing the armature to move back into said inoperative position for disengaging the movable contact from said fixed contact upon deenergization of the coil;

said relay characterized in that a stationary retainer means is provided on the base adjacent the angled portion of the armature to loosely engage that angled portion between the edge of the yoke and the retainer means for preventing said inside angle of the armature from departing beyond a predetermined allowable distance from the edge of the yoke;

that said movable spring is self-biased away from said fixed contact to thereby produce said return bias which is transmitted to said armature through said insulating actuator and said first armature leg while holding said insulative actuator between said movable spring and said first armature leg, and

that a fulcrum projection is provided on the base to receive the free end of the first armature leg when the armature is moved to its reset position, said actuator abutting against the first armature leg at a point inwardly of said fulcrum projection along the length of the first armature leg for transmitting to the armature said return bias as a torque which causes said armature within said allowable distance from the edge of the yoke to pivot about the fulcrum projection in a direction of urging said inside angle of the armature toward the edge of said yoke close enough so that upon the energization of the coil the inside angle of the armature can be firstly attracted to the edge of the yoke before the second armature leg is attracted to the core to substantially drive the movable spring by the first armature leg into contact with the fixed contact, whereby the armature can have its inside angle in exact coincidence with the edge of the yoke prior to being pivoted to the attracted position.

2. An electromagnetic relay as set forth in claim 1, wherein said actuator abuts at its end on the first armature leg at such an inclined angle that said return bias applies a force which acts in a direction of urging the inside angle toward the edge of the yoke along the length of the yoke while applying said torque to pivot the armature about said fulcrum projection.

3. An electromagnetic relay as set forth in claim 2, further including a cover of electrically insulative material fitted over said base to define therebetween a mounting space for said electromagnet and contact assembly, said base being integrally formed with a dividing wall which divides said mounting space into a magnet compartment for said electromagnet and a contact compartment for said contact assembly, said dividing wall formed integrally with said retainer means at its one end and with said fulcrum projection at the other end, said retainer means being in the form of an arcuate rib having its inner curved surface centered on the edge of said yoke, said fulcrum projection resting on said yoke, said dividing wall having therein a slit through which said insulative actuator extends between said movable spring and said first armature leg.

4. An electromagnetic relay as set forth in claim 1, wherein said actuator is formed at its ends with hooks each extending from the top end of the actuator and engaging in a corresponding notch formed in each of the upper edges of said movable spring and the first armature leg.