US3925742A

US3925742A - Mechanical latch relay

Info

Publication number: US3925742A
Application number: US482868A
Authority: US
Inventors: Rudolph E Muench
Original assignee: Fasco Industries Inc
Current assignee: Fasco Controls Corp
Priority date: 1974-06-25
Filing date: 1974-06-25
Publication date: 1975-12-09
Anticipated expiration: 1992-12-09

Abstract

The relay includes a housing containing an armature which is normally disposed in an inactive position, and which is pivoted by a manually operable button to an active position in which two sets of relay contacts are held closed by the armature. This pivotal movement of the armature also causes a flexible latch thereon to be engaged with the housing to latch the armature in its active position. After release of the button, if the relay coil is energized, the latch will disengage, and when the coil is thereafter deenergized the armature is released to its inactive position.

Description

United States Patent 11 1 Muench [4 1 Dec. 9, 1975 MECHANICAL LATCH RELAY I t I R d l h 1 V. Primary Examiner-Harold Broome 1 men or u o p Muench She N C Attorney, Agent, or FirmShlesinger, Fitzslmmons & [73] Assignee: Fasco Industries, Inc., Rochester, Shlesinger 22 Filed: June 25, 1974 [571 ABSTRACT The relay includes a housing containing an armature which is normally disposed in an inactive position, and

-- which is pivoted by a manually operable button to an 52 US. Cl. 335/186; 335/164; 335/170 I active position in which two sets of relay contacts are [51] Int. Cl. H01H 45/00 held Closed y the ma s piv tal mo ment of [58] Field of Search 335/186, 164, 165, 166, the armature also causes a flexible latch thereon to be 335/167, 168, 169, 170; 340/52 E; 180/82 C engaged with the housing to latch the armature in its active position. After release of the button, if the relay [56] Refere e Cit d coil is energized, the latch will disengage, and when UNITED STATES PATENTS the coil is thereafter deenergized the armature is re- 3,864,650 2/1975 Evans 335/186 leased to Its mact've posmon' 3,864,651 2/1975 Flanagan; 335/186 11 Claims, 6 Drawing Figures 42 4O 44 44 55 36 e2 54 5o 43 33 H 3o 35 32 I I l l US. Patent Dec. 9, 1975 Sheet 2 of3 3,925,742

FIG. 3

FIG. 4

U.S. Patent Dec. 9, 1975 Sheet 3 of 3 MECHANICAL LATCH RELAY This invention relates to relays, and more particularly to latching relays.

Most conventional latching relays include a movable armature, which is shifted from a first, released position to a second, switch operating position upon energization of an associated relay coil. When the armature reaches its second, or switch operating position, it is latched in that position until subsequently released or shifted back to its first position by a subsequent mechanical or electrical operation.

For certain applications, however, it has been found desirable to employ a manual operation for moving the switch arm to latching position. In the case of the present invention, for example, and as disclosed in greater detail hereinafter, a relay so constructed has been found useful in over-riding a faulty safety seat belt interlock system, which could otherwise prevent operation of a vehicle unless bypassed.

A principal object of this invention, therefore, is to provide a combined manually and electrically operable relay of the latching variety.

Still another object of this invention is to provide a mechanical latch relay which can be latched, initially, only by manual operation thereof.

A further object of this invention is to provide a manually-operable latching relay which is automatically released upon energization and subsequent deenergization of its associated operating coil.

It is an object also of this invention to provide a control circuit employing a relay of the character described over-riding the seat belt interlock system of an automotive vehicle, or the like.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings:

In the drawings:

FIG. 1 is a side elevational view of a latch relay made according to one embodiment of this invention, portions of the relay being shown in section and other portions thereof in full;

FIG. 2 is sectional view taken approximately along the line 2-2 in FIG. 1 looking in the direction of the arrows, and with portions of the upper switch contact arm and a lower terminal broken away for purposes of illustration;

FIG. 3 is a view similar to FIG. 1, but showing the operating button and actuator of the relay pushed to armature latching positions;

FIG. 4 is a view similar to FIG. 3, but showing the operating button and actuator in their fully released positions, and the relay armature latched in one of its operating positions;

FIG. 5 is a view similar to FIG. 4, but showing the armature latched in another of its operating positions by the now-energized operating coil of the relay, and showing the latching arm of the relay in released position; and

FIG. 6 is a wiring diagram illustrating one manner in which this relay may be wired to control the seat belt interlock system of an automotive vehicle, or the like.

Referring now to the drawings by numerals of reference, and first to FIGS. 1 to 5, 10 denotes generally a relay comprising a narrow, metal casing or housing 12, which is generally rectangular in cross-section and is closed at its upper end and open at its lower end. Seal- 2 ingly secured around its upper end in the flanged, lower end of casing 12 is a rigid base 14, which is made, for example, from a plastic, dielectric material. Base 14 has an integral, downwardly-projecting skirt portion, which encloses a deep recess 16 that is rectangular in cross-section.

Secured side by side at their upper ends to base 14 in the recess 16 by

rivets

18 and 19 are two

metal terminals

20 and 21. Two

additional terminals

22 and 23 are secured to base 14 by

rivets

24 and 25, respectively, to project downwardly in recess 16 to the right (FIG. 1) of

terminals

18 and 19.

Fastened centrally on the base 14 within the casing 12 by the upper end of the rivet 24 is a generally U- shaped, metal bracket 26. Secured between the

legs

27 and 28 of this bracket coaxially of the rivet 24 is a metal core 29. Wound in the usual manner on a spool 30, which surrounds the core 29, is a relay coil 31, which is shown schematically in FIGS. 1 and 3 to 5.

Coil 31 is electrically connected at one end to the terminal 20, and at its opposite end to a flexible switch contact or arm 32, the inner erid of which is secured on the upper end flange of the spool beneath a plastic collar 33. The free end of arm 32 is laterally offset to the left of center of bracket 26, as viewed in FIG. 2, and

j projects forwardly through a recess 34 in the upper end of bracket leg 27, and beneath the head 35 of a flexible operating arm 36, which projects radially from the plastic collar 33. The free end of switch arm 32 overlies the upper end of a stationary switch contact 38, which is fastened by the upper end of the rivet 25 to the top of base 14 adjacent one side thereof.

Hingedly mounted along one edge to the upper end of the bracket leg 28 by a flexible, metal strap 40 is a metal armature plate 41. Strap 40 is fastened at one end to armature 41, and at its opposite end by a rivet 42 to a forked lug 43, which projects rearwardly from bracket leg 28 adjacent its upper end. Armature'41 is thereby connected electrically through bracket 26 with the terminal 22.

Staked or otherwise secured as at 44 (FIG. 1) to the armature 41, and projecting diagonally downwardly through an opening 46 formed in the armature adjacent its free end, is a flexible latch 45. This latch is formed at its lower end with a hook portion 46 for engagement in a rectangular opening 48 in the lower end of the bracket leg 27.

Secured at its lower end on the base 14 by the rivet 19 and projecting upwardly into the housing 12 adjacent the rear end wall thereof is a metal post 50. An elongate switch arm 51 is secured by a rivet 52 to the upper end of post 50, and projects at its opposite end over the top of armature 41. Adjacent its free end arm 51 is bent at right angles downwardly as at 53 over the free end of armature 41, and then is bent rearwardly beneath the armature where its free end has secured thereon a metal contact 54. This contact is designed to engage a similar contact 55 that is fastened to the underside of armature 41 at its free end.

A plastic actuator 60 is secured intermediate its ends in an opening 61 (FIG. 1) which is in the switch arm 51. Actuator 60 has on its lower end a cylindrical projection or finger 62, which extends downwardly through the opening 46 in the armature to engage the flexible latch 45. The upper end of actuator 60 registers with a cylindrical stem that is integral with a hollow, domeshaped rubber actuating button 63, which is secured at its'lower end in an opening formed in the top of housing strap 40 holds the armature 41 in its upper, inactive position-against actuator 60, so that armature contact 55 is spaced above contact 54 of switch arm 51. Also at i this time the flexible switch contact 32 is urged by its own resilience to its inactive position spaced from stationary contact 38. Moreover, the flexible latch 45 is at this time in its released position.

To latch the relay, the button 63 is depressed manually to the position shown in FIG. 3, wherein post 64 engages and urges the actuator 60, and hence the switch arm 51, downwardly to urge armature 41 downwardly into contact with the upper end of the core 29, and wherein, nevertheless the contact 55 on the armature is still spaced from contact 54 on switch arm 51. Terminal 21 and switch arm 51 thus remain electrically disconnected from armature 41 and its terminal 22. The free end of the now-lowered armature 41, however, has engaged and urged the head 35 on flexible arm 36 downwardly against the ann 32 to engage arm 32 with the upper end of stationary contact 38, whereby the terminals and 23 are now connected electrically through the relay coil 31 and the

nowclosed switch contacts

32, 38. Also at this time, the tip 62 of actuator 60 has been swung downwardly. and

slightly inwardly about the fixed end of switch arm 51,

so that it urges the flexible latch 45 snugly against bracket leg 27 in such manner that the hook 46 on the latch engages in opening 48 in bracket leg 27 to latch.

the armature 41 in lowered position.

As will be seen from FIG. 4, as soon as the button 63 is released, switch arm51 returns to its uppermost position, thereby lifting the tip 62 of the actuator away from latch 45. During this movement, the armature 41 is allowed to swing slightly upwardly so that the hook 46 on the latch 45 engages the bracket leg 27 along the upper edge of the opening 48. Therefore, as the switch arm 51 and actuator 60 continue their upward move- I ments, the now-engaged hook 46 prevents latch 45 from springing outwardly to its released position, and the latch instead remains engaged with leg 27 and prevents further upward movement of armature 41. The armature is therefore latched in a partially lowered position as shown in FIG. 4. In this position the contact 55 on thearmature is engaged by the contact 54 on the forward end of the switch arm 51. Moreover, at this after the switch contacts have been latched into the po-;

sitions shown in FIG. 4. The energized coil 31 then draws the armature 41 downwardly into its lowermost position against the upper end of the core 29, thereby moving hook 46 downwardly from engagement with leg 27. Although this armature movement causes the switch arm 51 to dip slightly downwardly at its forward end, the actuator 60 and its tip 62 nevertheless remain disengaged from the armature 41 and the latch 45, respectively. Therefore, the resilience of latch 45 causes its hooked end 46 to swing outwardly to disengage book 46 from the opening 48 in leg 27. Although this operatively releases the latch 45, armature 41 remains in its lowered position (FIG. 5) as long as the relay coil 31 remains energized.

During this interval, the

switch contacts

32, 38 and 54, 55 remain closed. However, as soon as the circuit to the relay coil 31 is interrupted, the magnetic field surrounding core 29 collapses and the armature 41 is pivoted upwardly to its inactive position (FIG. 1) by its flexible hinge 40. This returns the moving parts to their inactive positions as shown in FIG. 1.

One application for which the relay 10 is particularly suited is shown diagrammatically in FIG. 6, wherein like numerals are employed to denote elements similar to those described in connection with FIGS. 1 to 5. In this embodiment the relay 10 is used in combination with a conventional automotive seat belt interlock system, of the type which is designed to prevent operation of an automobile engine when one or more of the vehicles occupants has failed to fasten his or her seat'belt properly. Such a system is represented in block form in FIG. 6, by a circuit denoted at 70.

As illustrated in FIG. 6, one end of the coil 31 of a relay 10 is connected by its terminal 20 to the vehicles power supply, such as-the positive terminal of its battery B, through the vehicles ignition switch 71. The other terminal 23 for the relay coil is connectable through switch arm 32 and contact 31 to ground, so that whenever switch 71 and

contacts

32 and 38 are closed, the relay coil 31 will be energized. Also in this system the terminal 22 for the armature 41 is connectable to the positive terminal of the vehicles battery B through the vehicles start switch 72. Moreover, the terminal 21 forswitch arm 51 is connectable through the starter solenoid 74 of the vehicle to ground. Solenoid 74 controls the normally-open starter switch 75, which selectively connects the starter motor M of the vehicle in the usual manner tothe positive terminal of battery B. Finally, the seat belt interlock circuit is connected at one end between the start switch 72 and the armature terminal 22 and at its opposite end between the switch terminal 21 and the starter solenoid 74.

In use, when each occupant of the vehicle is using his or her associated seat belt properly, the circuit 70 will be closed, or completed, so that whenever the start switch 72 is closed a circuitwill be completed from the battery B throughswitch 72, circuit 70 and the starter solenoid 74 to ground. Switch 75 is thereby closed by solenoid 74 long enough to start'the motor M. Undermanually to engage the latch 45 in the latching opening 48. This latches the armature 41 in its partially closed position, as illustrated in FIG. 4, wherein the

switch contacts

32, 38 and 54, 55 are maintained closed. Then, when the vehicle s ignition switch 71 is turned on, or is closed, the relay coil 31 is energized through the now-closed

contacts

32 and 38, thereby drawing armature 41 downwardly to its fully lowered position- (FIG. 5). Also at this time, assuming that the ignition switch is turned to starting position, the switch 72 will close, completing the energizing circuit for the starter solenoid 74 from the battery B through switch 72, the now-closed

contacts

54, 55, and the solenoid coil 74 to ground. Switch 75 is thereby closed to start the motor M, after which, under normal circumstances, the switch 72 will reopen in known manner. During the operation of the engine or vehicle motor M the ignition switch remains on its on or closed position, so that switch 71 remains closed to maintain coil 31 energized, and to hold the latch 45 in its released position. Consequently, whenever the ignition is thereafter turned off, thus opening switch 71, the relay armature 41 will be free to return to its uppermost or inactive position, thereby returning the operating parts of the relay to their initial or inactive positions as shown in FIGS. 1 and 2.

From the foregoing it will be apparent that the instant invention provides a relatively simple and extremely reliable mechanical latching relay which enables, for example, selective bypassing of a seat beltinterlock system in an automotive vehicle, or the like. The relay 10 can be activated only by physically depressing the button 63. Once this button has been fully depressed and fully released the relay is mechanically latched in an operative position in which the associated

electrical contact

32, 38 and 54, 55 are held closed. When used in conjunction with a belt interlock system therefore, it is not necessary manually to hold the button 63 in a depressed position in order to start the engine, nor is it necessary to manually release the relay contacts after they have been used to bypass the interlock system. This leaves the hands of the operator free to operate the vehicle, once the button 63 has been operated.

While the invention is useful in connection with safety automotive seat belt systems it is by no means confined to such a usage. The prime advantage of the relay 10 is that as soon as the relay coil 31 is energized the latch 45 will be released, so that when thereafter power is removed from the realy coil, the relay will automatically return to its inactive or normal position, in which all of its contacts are open. Thus, the coil 31 operates both to hold the relay contacts closed, when energized, and operates, when deenergized, to effect automatic opening of the associated relay contacts.

Again, the only manual operation required of an operator is to push the button 63 to effect operation of the relay. Thereafter the relay can be released only by operation of the coil 31.

Although the invention has been illustrated and described herein in connection with certain embodiments thereof, it will be understood, then, that it is capable of further modification and uses, and that this application is intended to cover any modification that comes within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

l. a latching relay, comprising a housing,

a plurality of spaced electrical terminals, secured to said housing a pair of switches in said housing,

actuating means on said housing operable manually to close one of said switches to complete a first circuit between a first pair of said terminals.

6 means for releasably latching said one switch in its closed position each time it is moved thereto, means for closing the other said switches to complete a second circuit between a second pair of said terminals after said one switch has been latched closed, and means including a relay coil in said housing operative, when energized, to release said latching means,

said coil being connected in series with said one switch, whereby said coil may'be energized only when said one switch has been closed by said actuating means.

2. A latching relay as defined in claim 1, including holding means operative upon the energization of said coil and the release of said latching means to hold said switches closed until said coil is subsequently deenergized.

3. A latching relay as defined in claim 2, wherein said actuating means comprises a button mounted on said housing for movement manually from the exterior of said housing from an inoperative to an operative position thereby to effect closure of said one switch, and

means normally holding said other switch open and operative to close said other switch after said one switch is latched closed and said button has returned to its inoperative position.

4. A latching relay as defined in claim 1, wherein a magnetizable armature is mounted in said housing adjacent said coil for movement responsive to the magnetic field developed by said coil, when the latter is energized,

resilient means normally urges said armature to an inactive position in which said field is not strong enough to effect movement of said armature,

said latching means comprises a latching element on said armature, and said actuating means is operative, upon closing said one switch, simultaneously to move said armature from its inactive position to a first active position, and to move said latching element from a released position to a latched position in which said latching element releasably holds said armature in said first active position. 5. A latching relay as defined in claim 4, including means mounting said armature for movement by said field from said first active position to a second active position, when said coil is engergized, and

means resiliently mounting said latching element on said armature and operative to shift said element to its released position, each time said armature is moved to said second position,

said field developed by said coil being operative to hold said armature in said second active position until said coil is deenergized.

6. A latching relay as defined in claim 5, wherein said one switch comprises a stationary contact connected to one of said first pair of terminals, and

a movable contact connected to said coil and movable by said armature into engagement with said stationary contact to close said one switch when said armature is in either of its active positions.

7. A latching relay as defined in claim 5, wherein said actuating means comprises a reciprocable actuator movable manually from a first to a second position to shift said armature to an active position,

, v 7 said means for closing said other switch comprises a flexible switch arm movable with said actuator,

said other switch comprises a first contact on said armature and a second contact on said switch arm normally disposed in spaced relation to saidfirst contact, and

said switch arm is operative, when said armature is in I either of its active positions, to move said second contact into engagement with said first contact to close said bther switch upon return of said actuator from its second to its first position.

'8. A latching relay as defined in claim 5, including means for holding each of said pair of switches closed when said armature is in eitherof its active positions.

' 9. A latching relay, comprising a housing,

a plurality of electrical terminals secured to said housing,

a-relay coil mounted in said housing,

an armature mounted atone end of said coil to pivot between two active positions in which the armature is responsive to a magnetic field developed by said coil, when energized, and an inactive position in which the armature is not responsive to said field,

a pair of normally-open switches in said housing,

means connecting one of said switches in series circuit with said coil between two of said terminals,

means connecting the other of said switches in series with a second circuit extending between two others ofsaid terminals, 7

manually operable means on said housing including a button movable manually from a first to a second position to shift said armature from its inactive position to one of its active positions,

a flexible latch mounted on said armature and movable by the last-named means into engagement with cooperating latching means in said housing releasably to latch said armature in said one active position, when said coil is deenergized, and

means for closing said switches when said armature is in either of its active positions and said button is in its first position,

said field being operative, when said coil is energized,

' to shift said armature from said one to the other of its active positions, and to retain said armature in said other active position until said coil is subsequently deenergized,

said flexible latch being releasable automatically from said cooperating latching means upon movement of said armature to said other active position, whereby said armature is free to'return to its inactive position when said coil thereafter is deenergized.

10. A latching relay, comprising a housing, p

a plurality of electrical terminals secured to said housing, a

a realy coil mounted in said housing inseries circuit with one of said terminals and having a magnetizable core mounted coaxially therein in series circuit with said one terminal,

an armature movably mounted in said housing for cooperation with said core and carrying a first electric contact,

a first flexible switch arm movably mounted in said housing in series circuit with a second of said terminals and carrying a second electric contact engageable with said first electric contact,

a flexible latching member secured to said armature to move therewith and normally urging said armature in one direction, 4

a detent for holding said latching member and said armature in a latched position in said housing,

a manually movable actuator. mounted in said housing in position to move said armature and said switch arm in one direction and to dispose said latching member in position to engage said detent,

a third electric contact fixedly mounted in said housing in series circuit with a third of said terminals,

a second flexible switch arm mounted in series circuit with said coil and operable upon movement in one direction to engage said third contact,

an actuating member positioned to be engaged by said armature when said armature is moved by said actuator insaid one direction of movement of said armature to engage said second switch arm with said third electric contact,

said first switch arm being operative upon release of said actuator tomove said second electric contact into engagement with said first electric contact, and r said core being operative upon energization of said coil to move said armature and said first flexible switch arm again in a direction to engage said first and second contacts, I v

said latching member flexing thereupon to disengage said detent.

11. A latching relay, comprising a housing,

a relay coil mounted in said housing and having a magnetizable core,

a movable armature mounted in said housingand disposed in operative relation to said core,

a resilient latching member connected to said armature and normally urging said armature normally to a position spaced from said core,

a detent mounted in said housing for engaging said latching member,

manually-operable means movable from a normal, inoperative position to operative position to move said armature from a first inoperative position to a second position in engaagement with a first said core, and

means operative upon movement by said manually- I and through said core.

Claims

1. A LATCHING RELAY, COMPRISING A HOUSING, A PLURALITY OF SPACED ELECTRICAL TERMINALS, SECURED TO SAID HOUSING A PAIR OF SWITCHES IN SAID HOUSING, ACTUATING MEANS ON SAID HOUSING OPERABLE MANUALLY TO CLOSE ONE OF SAID SWITCHES TO COMPLETE A FIRST CIRCUIT BETWEEN A FIRST PAIR OF SAID TERMINALS. MEANS FOR RELEASABLY LATCHING SAID ONE SWITCH IN ITS CLOSED POSITION EACH TIME IT IS MOVED THERETO, MEANS FOR CLOSING THE OTHER SAID SWITCHES TO COMPLETE A SECOND CIRCUIT BETWEEN A SECOND PAIR OF SAID TERMINALS AFTER SAID ONE SWITCH HAS BEEN LATCHED CLOSED, AND MEANS INCLUDING A RELAY COIL IN SAID HOUSING OPERATIVE, WHEN ENERGIZED, TO RELEASE SAID LATCHING MEANS, SAID COIL BEING CONNECTED IN SERIES WITH SAID ONE SWITCH, WHEREBY SAID COIL MAY BE ENERGIZED ONLY WHEN SAID ONE SWITCH HAS BEEN CLOSED BY SAID ACTUATING MEANS.

3. A latching relay as defined in claim 2, wherein said actuating means comprises a button mounted on said housing for movement manually from the exterior of said housing from an inoperative to an operative position thereby to effect closure of said one switch, and means normally holding said other switch open and operative to close said other switch after said one switch is latched closed and said button has returned to its inoperative position.

4. A latching relay as defined in claim 1, wherein a magnetizable armature is mounted in said housing adjacent said coil for movement responsive to the magnetic field developed by said coil, when the latter is energized, resilient means normally urges said armature to an inactive position in which said field is not strong enough to effect movement of said armature, said latching means comprises a latching element on said armature, and said actuating means is operative, upon closing said one switch, simultaneously to move said armature from its inactive position to a first active position, and to move said latching element from a released position to a latched position in which said latching element releasably holds said armature in said first active position.

5. A latching relay as defined in claim 4, including means mounting said armature for movement by said field from said first active position to a second active position, when said coil is engergized, and means resiliently mounting said latching element on said armature and operative to shift said element to its released position, each time said armature is moved to said second position, said field developed by said coil being operative to hold said armature in said second active position until said coil is deenergized.

6. A latching relay as defined in claim 5, wherein said one switch comprises a stationary contact connected to one of said first pair of terminals, and a movable contact connected to said coil and movable by said armature into engagement with said stationary contact to close said one switch when said armature is in either of its active positions.

7. A latching relay as defined in claim 5, wherein said actuating means comprises a reciprocable actuator movable manually from a first to a second position to shift said armature to an active position, said means for closing said other switch comprises a flexible switch arm movable with said actuator, said other switch comprises a first contact on said armature and a second contact on said switch arm normally disposed in spaced relation to said first contact, and said switch arm is operative, when said armature is in either of its active positions, to move said second contact into engagement with said first contact to close said other switch upon return of said actuator from its second to its first position.

8. A latching relay as defined in claim 5, including means for holding each of said pair of switches closed when said armature is in either of its active positions.

9. A latching relay, comprising a housing, a plurality of electrical terminals secured to said housing, a relay coil mounted in said housing, an armature mounted at one end of said coil to pivot between two active positions in which the armature is responsive to a magnetic field developed by said coil, when energized, and an inactive position in which the armature is not responsive to said field, a pair of normally-open switches in said housing, means connecting one of said switches in series circuit with said coil between two of said terminals, means connecting the other of said switches in series with a second circuit extending between two others of said terminals, manually operable means on said housing including a button movable manually from a first to a second position to shift said armature from its inactive position to one of its active positions, a flexible latch mounted on said armature and movable by the last-named means into engagement with cooperating latching means in said housing releasably to latch said armature in said one active position, when said coil is deenergized, and means for closing said switches when said armature is in either of its active positions and said button is in its first position, said field being operative, when said coil is energized, to shift said armature from said one to the other of its active positions, and to retain said armature in said other active position until said coil is subsequently deenergized, said flexible latch being releasable automatically from said cooperating latching means upon movement of said armature To said other active position, whereby said armature is free to return to its inactive position when said coil thereafter is deenergized.

10. A latching relay, comprising a housing, a plurality of electrical terminals secured to said housing, a realy coil mounted in said housing in series circuit with one of said terminals and having a magnetizable core mounted coaxially therein in series circuit with said one terminal, an armature movably mounted in said housing for cooperation with said core and carrying a first electric contact, a first flexible switch arm movably mounted in said housing in series circuit with a second of said terminals and carrying a second electric contact engageable with said first electric contact, a flexible latching member secured to said armature to move therewith and normally urging said armature in one direction, a detent for holding said latching member and said armature in a latched position in said housing, a manually movable actuator mounted in said housing in position to move said armature and said switch arm in one direction and to dispose said latching member in position to engage said detent, a third electric contact fixedly mounted in said housing in series circuit with a third of said terminals, a second flexible switch arm mounted in series circuit with said coil and operable upon movement in one direction to engage said third contact, an actuating member positioned to be engaged by said armature when said armature is moved by said actuator in said one direction of movement of said armature to engage said second switch arm with said third electric contact, said first switch arm being operative upon release of said actuator to move said second electric contact into engagement with said first electric contact, and said core being operative upon energization of said coil to move said armature and said first flexible switch arm again in a direction to engage said first and second contacts, said latching member flexing thereupon to disengage said detent.

11. A latching relay, comprising a housing, a relay coil mounted in said housing and having a magnetizable core, a movable armature mounted in said housing and disposed in operative relation to said core, a resilient latching member connected to said armature and normally urging said armature normally to a position spaced from said core, a detent mounted in said housing for engaging said latching member, manually-operable means movable from a normal, inoperative position to operative position to move said armature from a first inoperative position to a second position in engaagement with a first said core, and means operative upon movement by said manually-operable means of said armature manually to said second position to establish an electric circuit to said core and to move said armature to said second position, and means operative, upon release of said manually-operable means, to return said manually-operable means to its normal position and to disengage said armature from said core and to establish simultaneously an electric circuit to said coil and to disengage said latching means from said detent while maintaining the electric circuits through said coil and through said core.