US 3864651 A
A manually set magnetic relay is utilized to override an electrical interlock in a one-time operation. Once the relay has been utilized, it automatically disables itself and must be manually set again for another operation. The relay includes an electromagnetic coil which closes a load switch connected in parallel with the electrical interlock. A secondary circuit for energizing the coil includes a second switch formed by a pair of flexible conductors at least one being flexible. A flexible latch engages one of the conductors of the second switch as the coil is energized and closes the load switch. The latch continues to hold the second switch in the latched and open condition when the coil is de-energized. To close the second switch and make energization of the coil possible, a manually actuated plunger engages the flexible latch and displaces it away from the one of the flexible conductors which then moves from the latched position to a position in contact with the other conductor of the second switch. The plunger also holds the load switch open during the unlatching operation to provide trip-free operation of the relay.
Claims available in
Description (OCR text may contain errors)
[ Feb. 4, 1975 United States Patent [1 1 Flanagan MANUALLY SET MAGNETIC RELAY ABSTRACT  Inventor: Charles D. Flanagan, Attleboro,
 Assignee: Texas Instruments Incorporated,
y disables her oper- Dallas, Tex.
ation. The relay includes an electromagnetic coil which closes a load switch connected in parallel with the electrical interlock. A secondary circuit for energizing the coil includes a second switch formed by a 335/136, 123/179, 130/32 1 pair of flexible conductors at least one being flexible. 335/164, 340/52 E f the conductors of the Int. Cl. Second Switch as the coil is energized and closes the load switch. The latch continues to hold the second switch in the latched and open condition when the coil A flexible latch engages one o  Field of Search 335/l86, 166
ose the second switch and make i1 possible, a manually actuated flexible latch and displaces it the flexible conductors which then moves from the latched position to a position in contact with the other conductor of the second switch. The plunger also holds the load switch open during f dm m OBIM m o i e fl W h Z g i. n W pum 8 0 nmr nema er. y m w BEN-a B E 7 I2 2 7 I15 v l. E t 3H T m. 5A MW wfl S WM 3 3 M 2 m H E m U1... T L m m 008 P m 035 C l 1 S 6 8 59 CT y 6 ,0 A uh C TMM an a m PF 0 E49 58 46 31 I99 3 NHH 06 44 6] um 3 23 the unlatching operation to provide trip-free operation of the relay.
Primary Examiner-Harold Broome Attorney, Agent, or Firm-John A. Haug; James P. McAndrews 6 Claims, 5 Drawing Figures PATENTEU 4W5 SHEET 18? 2 LOGIC MODULE STARTER SOLENOID sum 2 or 2 PATENTEU FEB 9 5 5 mm F I MANUALLY SET MAGNETIC RELAY CROSS-REFERENCE TO RELATED APPLICA- TIONS This application relates to subject matter disclosed and claimed in copending application Ser. No. 421.889 entitled, Manually Set Switching Devices filed Dec. 5, I973, and copending application Ser. No. 421,902, entitled "Manually Set Magnetic Relay", filed Dec. 5, 1973. and copending application Ser. No. 421,904, entitled Push Button, filed Dec. 5, W73. the copending applications having the same assignee as the present application.
BACKGROUND OF THE INVENTION This invention relates to the field of electrical relays and, more particularly, is related to a single-cycle magnetic relay which must be manually set in an enabled condition prior to each operation.
It is well known to provide electrical interlocks in systems to prevent operation unless specific conditions have been met. For example, as a safety measure in automobiles, the ignition system may be disabled until the driver and all of his passengers have fastened their seat belts. To implement such a system, an electrical interlock operated by sensors or switches sequentially set by the driver and passengers entering the car and fastening the belts may be provided in the ignition system of the automobile. Unless the belts are fastened after entry, the interlock disables the ignition system and the engine cannot be started.
It will be recognized that a failure of the electrical interlock system may completely disable the ignition system and prevent operation of the automobile. Such a situation may not only be frustrating to the driver and his passengers but also could prove to be a serious hazard particularly in an emergency situation in which the automobile must be moved.
To remedy the situation and eliminate the possible hazards posed by the electrical interlock, it has been suggested that an override relay be provided to bypass the electrical interlock. The relay must be manually set before each override operation and disabled after operation. Naturally, to prevent repeated use of the relay, it is located in a position not readily accessible to the driver except in an emergency situation, and one likely location for the relay is the engine compartment.
It is, accordingly, a general object of the present invention to disclose a manually set magnetic relay which automatically disables itself when de-energized to limit its use to single-cycle or one-time operations.
SUMMARY OF THE INVENTION The present invention resides in a manually set magnetic relay for single-cycle or one-time operations. The relay has particular utility as an overriding device for an electrical interlock since the relay must be manually set prior to each overriding operation and automatically disables itself after a single operation so that the interlock may again perform its intended function.
The magnetic relay is comprised of first switch means which are operatively connectible in the load circuit controlled by the electrical interlock. The first switch means includes a cantilevered, flexible clapper arm.
Electromotive force generating means including an electromagnetic coil is operatively connected with the clapper arm of the first switch means for closing the first switch means upon energization of the coil. Such energization in the automobile interlock system takes place at the beginning of engine starting procedures.
Second switch means serially coupled with the coil of the electromotive force generating means permit energization of the coil and include first and the second flexible conductors having portions positioned in overlying relationship for flexing in and out of contact and thereby closing and opening the second switch. The second conductor extends in transverse relationship to the clapper arm of the first switch means and is engaged by the clapper arm for flexing in and out of contact with the first conductor of the second switch means. When the clapper arm of the first switch means closes as the relay is pulled in, the second conductor moves the first conductor into a position above a latch means which is operatively engageable with the first conductor to hold it in a latched position out of contact with the first conductor after de-energization of the electromagnetic coil. With the first conductor latched, the coil cannot be re-energized.
Unlatching of the first conductor of the second switch means to enable the relay is performed by a manually operable actuator means engaged with the latching means for releasing the conductor from the latched position. The actuator means includes a plunger having a camming surface which contacts a flexible member of the latching means and moves the member away from the first conductor to allow the first conductor to snap into contact with the second conductor and close the second switch means.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an electrical diagram illustrating one environment in which the manually set magnetic relay of the present invention may be employed.
FIG. 2 is a perspective view of the magnetic relay in its disabled condition.
FIG. 3 is an enlarged end view of the magnetic relay in FIG. 2 partially in section and illustrating the compo nents in the disabled condition of the relay.
FIG. 4 is an end view of the relay similar to that in FIG. 3 and illustrates the components during manual actuation for setting the relay in an enabled condition.
FIG. 5 is an end view similar to FIGS. 3 and 4 and illustrates the components when the relay is pulled in.
DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is an electrical diagram showing schematically the manually set magnetic relay of the present invention in the starting circuitry of an automobile having an electrical ignition interlock. The interlock normally prevents energization of the electrical starter motor unless the seat belts have been properly fastened in each of the occupied seats of the automobile. It should be understood. however, that the magnetic relay of the present invention can be employed in other environments to override an interlock or perform other functions to which its operation is suited.
The manually set magnetic relay of the present invention, generally designated I0, is connected serially in the electrical starting circuit between the ignition switch l2 and the starter solenoid I4 on the starter motor (not illustrated). The ignition switch I2 is, of course, connected to one of the battery terminals, the B+ terminal being illustrated, and the starter solenoid 14 would be connected to the other terminal. illustrated as the ground terminal. through the frame of the automobile. A starting switch 16 is also serially connected with the magnetic relay between the ignition switch 12 and the solenoid 14. The ignition switch l2 and the starting switch 16 are generally incorporated in a single switching device manually operated by means of the ignition key and are closed sequentially, the switch 12 being closed first and the switch 16 being closed second by rotating the ignition key through several index positions, the last of which closes the switch 16 to energize the starter solenoid l4 and turn the starter motor. Usually, the last index position is springbiased so that the starting switch 16 opens upon release of the key. The ignition switch [2 also energizes other portions of the electrical system such as the spark coil, fuel pumps and instrumentation needed during operation of the engine.
The seat belt interlock system includes a logic moduie l8 and an interlock relay 20. The logic module 18 receives signals from sensing switches indicating which seats of the automobile are occupied and which seat belts have been fastened. If the seats are first occupied and then the respective seat belts are fastened in that order. a "go" signal normally issues from the module 18 to actuate the coil of the interlock relay 20 and close the relay contacts. The relay contacts in the closed position complete the starting circuit through the switches 12 and 16 to the starter solenoid l4 and permit the starter motor to be engaged. If the logic module detects an unfastened seat belt in one of the occupied seats, or if the sensing switches are not actuated in the proper order. indicating. for example. a permanently buckled seat belt, the interlock relay 20 is not energized and the starting circuit remains open. Also, however, if the logic module l8 is faulty and inoperative, the interlock contacts may not close and starting the automobile cannot take place in its intended fashion.
The manually set magnetic relay 10 is employed in parallel with the interlock relay 20 to override the interlock when it is inoperative for any reason and therefore permits the automobile to be started. The magnetic relay I is comprised of electrical components including an electromagnetic relay coil 22, a load switch 24 operated by the coil and a latching switch 26 in a secondary circuit with the coil. The contacts of the load switch 24 are connected in parallel with the contacts of the interlock relay 20 so that they may duplicate or override the relay 20 when the interlock system fails. In order to close the load switch 24, however, the latching switch 26 must be closed and the magnetic coil 22 must be energized through the ignition switch 12. The latching switch 26, as described in greater detail below, must be manually set to the closed position and is automatically opened to disable the relay when the coil 22 is de-energized after the ignition switch 12 is opened to shut off the automobile engine. Hence, the magnetic relay 10 provides a single-cycle override or bypass operation of the seat belt interlock system for each operation of the automobile engine. It will be understood that the manually set magnetic relay 10 would be located in a position not readily accessible to the driver of the automobile. for example, in the engine compartment, so that the seat belt interlock sys tem is not routinely overridden,
FIG. 2 illustrates a construction and the principal components of the manually set magnetic relay N]. The
principal components of the relay including the coil 22, the load switch 24 and the latching switch 26 are all supported on a base plate 30 formed preferably from an insulating material such as a plastic or fiberboard. The electromagnetic coil 22 includes a U-shaped ferromagnetic support bracket 32 around which the coil 22 is wound. The bracket 32 is fixedly riveted to a platform 34 on the base plate 30 by means of a terminal post 36. A connecting pin 38 is attached to the lower end of the post 36 for plugging the relay into an electrical connector. One lead 40 from the coil 22 is connected to a terminal post 42 extending through the base plate 30 to a connecting pin 44. The other lead 46 from the coil 22 is connected to a terminal post 48 on the base plate.
The U-shaped bracket 32 is mounted on the platform 34 in cantilever fashion so that the free end of the bracket is located over a resilient and conductive clapper arm 50. The clapper arm 50, like the bracket 32, is mounted in cantilever fashion between the platform 34 and the bracket and is held by the terminal post 36. In the unflexed condition, the clapper arm 50 extends generally parallel to the upper surface ofthe base plate 30 and a small gap exists between the clapper arm and the free end of the bracket 32. lt will be readily understood that energization of the coil 22 generates magnetic flux through the ferromagnetic bracket 32 and the conductive and ferromagnetic clapper arm 50 and pulls the clapper arm upwardly against the free end of the bracket 32 to close the gap. Clapper arm 50 may also be a composite of an electrically conductive but non-ferromagnetic arm and a ferromagnetic section in operable engagement therewith between the fixed and the free end of the bracket 32.
The resilient and conductive clapper arm 50 includes at its free end an electrical contact 52 and thus forms a part of the load switch 24. The other electrical contact 64 of the load switch 24 is supported directly above the contact 52 on a bracket 56 attached to the base plate 30 by a terminal post (not shown) so that the contacts 52 and 54 meet when the clapper arm 50 is pulled upwardly by the electromagnetic coil 22. A connecting pin (not shown) similar to pins 38 and 44 is also connected to the terminal post holding the bracket 56.
The latching switch 26 in the secondary circuit controlling the coil 22 is formed by two generally flat conductors 60 and 62, as described both are resilient although it should be noted that one of the two may be rigid. The conductor 60 is riveted to the base plate 30 by means of a terminal post 64 and extends in cantilever fashion from the post over the plate 30. A connecting pin 66 similar to pins 38 and 40 is secured to the bottom end of the post below the plate 30. At the free end of the cantilevered conductor 60 is an electrical contact 88 which overlies and mates with a contact 70 on the end of the flexible conductor 62. The conductor 62 is riveted to the base plate 30 by the terminal post 48 and is in electrical contact with the lead 46 at the terminal post. The conductor 62 extends in cantilever fashion from the terminal post 68 in a direction generally parallel to the clapper 50 and then extends transversely across the clapper to the free end bearing the contact 70. An insulating pad 72 is positioned on the clapper 50 directly below the conductor 62 so that the clapper arm 50 when raised by the coil 22 lifts the conductor 62 without establishing electrical contact with the conductor. The conductor 62 in the unflexed condition may be positioned as illustrated at an elevation above the base plate 30 providing space between the conductor and the insulating pad 72 when the clapper arm 50 is not pulled upwardly by the coil 22.
A resiliently flexible, one-piece latch 80 is fixed to the base plate 30 at a position laterally adjacent the free end of the flexible conductor 60. The one-piece latch 80 includes a projecting, inclined tang 82 on which the conductor 60 is shown resting in FIG. 2. The height of the tang 82 above the base plate 30 is selected in conjunction with the bracket 32, the clapper arm 50 and conductor 62 to locate the contacts 68 and 70 of switch 26 open or out of contact when the coil 22 is de' energized and the conductor 60 is resting on the tang. Furthermore. when the clapper arm 50 is elevated by the coil 22, the arm 50 lifts the conductor 60 to a position just above the latch 80 by means of the intervening conductor 62 extending transversely across the clapper arm 50 and the insulating pad 72.
A manually actuated plunger 90 is supported for reciprocation in slots of two upright guide posts 92 and 94 at opposite sides of the base plate 30. The posts 92 and 94 may be formed integrally with the base plate or separately attached to the plate. A return spring 96 extends between the tops of the posts 92 and 94 and has a central slot which captures a knob 98 at the top of the plunger 90. The plunger 90 may, therefore, be reciprocated along an axis extending parallel to the slots in the posts 92 and 94 and perpendicular to the base plate. In operation of the relay, the knob 98 and remaining portion of the plunger 90 are manually depressed toward the base plate 30 and when released. the plunger is returned to the position illustrated by the spring 96.
OPERATION The operation of the manually set magnetic relay l0 and the remaining structural details of the relay are described below in connection with FIGS. 3-5 which show the relay in three different and sequential stages of operation.
FIG. 3 illustrates the positions of the relay components when the relay is in a de-energized and disabled condition. The flexible conductor 60 is held in the latched position on top of the tang 82 and the flexible conductor 62 is in an unflexed condition locating the contact 70 directly below and spaced from the contact 68. The switch 26 formed by the conductors 60 and 62 is, therefore, open and the secondary circuit through the relay coil 22 is interrupted.
Since the circuit through the coil 22 is interrupted, it is tie-energized and the resilient clapper arm 50 is located in its unflexed position spaced slightly above the base plate 30 but well below the bracket 56 so that the contacts 52 and 54 are in spaced relationship, one above the other. The load switch 24 is, accordingly, open and the electrical interlock relay (FIG. 1) is free to perform its intended function of preventing engine start-up unless the logic module 18 is satisfied that the seat belts in occupied seats have been appropriately fastened.
FIG. 4 illustrates the positions of the relay components when the manually actuated plunger 90 is fully depressed to initiate an override operation. It will be observed in FIGS. 2 and 4 that the latch 80 has an extension bearing a camming surface I00 engaged by a corresponding camming surface 102 on the actuated plunger as the plunger is depressed in the slots of the guide posts 92 and 94. The camming surfaces are disposed at a slight angle to the axis of reciprocation of the plunger. Movement ofthe plunger vertically toward the base plate 30 causes the camming surfaces I02 and I04 to slide relative to one another and displaces the latch together with the tang 82 from the phantom position in the lateral direction generally perpendicular to the motion of the plunger along the axis of reciprocation. As the latch moves to the position illustrated in FIG. 4 from the phantom position. the tang 82 is removed from its supporting position under the resilient conductor 60 and the conductor snaps downwardly onto the conductor 62. The electrical contacts 68 and 70 meet and thus close the switch 26. The secondary circuit in the relay through the coil 22 is complete and the coil 22 in FIG. I is energized as soon as the ignition switch I2 is closed.
To prevent the electrical interlock from being permanently defeated by jamming the manually actuated plunger in the depressed position illustrated in FIG, 4. the lower edge 104 of the plunger 90 contacts the clapper arm 50 and presses the clapper arm against the base plate 30 when the tang 82 is disengaged from the flexible conductor 60. The load contacts 52 and 54 of the switch 24 are, therefore, positively spaced from one another and the interlock relay 20 of FIG. I is not by passed. It will be understood that if the plunger 90 in the depressed position did not hold the load switch 24 open, the switch 26 in the secondary circuit would always remain closed and the coil 22 could be energized every time the ignition switch was turned on to pull the load switch 24 closed. The extended lower edge I04 of the plunger 90, therefore, provided trip-free operation which means that the load contacts do not close until manual actuation to set the relay is fully completed.
FIG. 5 illustrates the relay I0 after manual actuation is fully completed. The plunger 90 has been returned to an elevated position by the return spring 96 in FIG. 2 so that the lower edge I04 is well above the clapper arm 50. With the plunger 90 elevated. the camming surfaces 100 and I02 are no longer engaged and the flexible latch 80 is returned to its unflexed position. When the ignition switch is turned on to energize the coil 22, the clapper arm 50 is pulled upwardly and brings the contacts 52 and 54 of the load switch 24 together. At this point, the interlock relay 20 in FIG. I has been by-passed and starting of the automobile engine is possible.
It will be observed in FIG. 5 that the lifting of the clapper arm 50 concomitantly lifts the flexible conductors 60 and 62 so that the conductor 60 slides over the inclined tang 82 to a position immediately above the tang. Lifting of the conductors comes about due to the engagement of the insulating pad 72 on the clapper arm 50 with the conductor 62 and the engagement of the contact 70 on-the conductor 62 with the contact 68 on the conductor 60. The tang 82 does not interfere with the lifting of the conductor 60 since the latch 80 merely flexes laterally away from the conductor as the conductor engages the inclined lower surface of the tang during the upward movement.
When the ignition switch [2 in FIG. 1 is subsequently opened to shut the automobile engine off. the coil 22 of the relay is de-energized and the clapper arm 50 drops to its rest position illustrated in FIG. 3. The contacts 52 and 54 of the load switch 24 thus open and enable the interlock relay 20 in FIG. I to again perform its intended function. In addition, the flexible conductor 62 assumes a rest position illustrated in FIG. 3 between the clapper arm 50 and the conductor 60. The conductor 60 having been located above the tang 82 in FIG. and without the support provided by the clapper arm 50 and conductor 62, drops downwardly onto the tang as shown in FIG. 3. At the same time. contacts 68 and 70 of the switch 26 open and break the secondary circuit through the coil 22. The components of the relay have, therefore, all returned to their initial positions in which the relay is disabled and the electrical interlock relay is again enabled. Subsequent override operations may be repeated as described above; however. each operation must be prefaced by manually actuating the plunger 90 since the relay automatically resets itself in a disabled condition whenever the ignition switch 12 is turned off.
While the present invention has been described in a preferred embodiment, it should be understood that modifications and substitutions in the detailed structure can be had without departing from the spirit of the invention. For example. the manually actuated plunger 90 and the latch 80 may take forms different from those illustrated provided that the camming surfaces of the latch and plunger engage one another while the plunger is depressed to deflect the latch and release the conductor 60 from its latched position on top of the tang 82. The flexible conductor 62 may rest on the insulating pad 72 at all times as suggested above. The coil 22 may be supported in an upright position relative to the clapper arm 50 as shown. for example, in copending application entitled Manually Set Magnetic Relay referenced above. Accordingly, the present invention has been described in a preferred embodiment by way of illustration rather than limitation.
I. A manually set magnetic relay for one time operations comprising:
first switch means operatively connectible in a load circuit and including a cantilevered, flexible clapper arm;
electromotive force generating means including a coil operatively connected with the clapper arm of the first switch means for closing the first switch means upon energization of the coil;
second switch means serially coupled with the coil to permit energization of the coil, the second switching means including first and second conductors having portions positioned in overlying relationship for flexing in and out of contact to thereby close and open the second switch means, the second conductor extending in transverse relationship to the clapper arm of the first switch means and being engaged by the clapper arm for flexing in and out of Contact with the first conductor of the second switch means; latch means operatively engageable with the first conductor of the second switch means for holding 5 the first conductor in a latched position out of contact with the second conductor of the second switch means; the electromotive force generating means being operatively coupled to the first conductor of the second switch means for moving the first conductor into the latched position; and manually operable actuator means engageable with the latching means for releasing the first conductor of the second switch means from the latched position. 2. A manually set magnetic relay as defined in claim 1 wherein:
the latch means includes a flexible latch mounted adjacent the first conductor of the second switch means for engagement with the first conductor and flexibly movable out of engagement with the first conductor. 3. A manually set magnetic relay as defined in claim 2 wherein:
the manually operable actuator means comprises a plunger mounted adjacent the latch for movement toward and away from the latch and disposed to flex the latch out of contact with the first conductor. 4. A manually set magnetic relay as defined in claim 3 wherein:
the plunger is a reciprocating plunger having a given axis of reciprocation; and the latch includes of camming surface engaged by the plunger and disposed at an angle to the axis of reciprocation. 5. A manually set magnetic relay as in claim 1 wherein:
the first and second conductors of the second switch means are resiliently flexible conductors mounted in cantilever fashion with the free end portions of the conductors overlying one another for flexing in and out of contact; and the latch means includes a resiliently flexible, onepiece latch having a tang engageable with the first conductor. 6. A manually set relay as defined in claim 5 wherein: the electromagnetic force generating means is operatively coupled to the first conductor of the second switch means by means of the clapper arm and the second conductor of the second switch means is engaged by the clapper arm.