US2922086A - Bi-stable relay circuit - Google Patents

Description

, .Im-19, 195o C. W. STIDGER BI-STABLE RELAY CIRCUAIT Filed July 30. 1956 Arramffs" United States Patent C 2,922,086 'BI-STABLE RELAY CIRCUIT Clifford W. Stidger, San Lorenzo, Calif., assignor to Gerber Products Company, Fremont, Mich., a corporation of Michigan Application July 30, 1956, Serial No. 600,914

, 1 Claim. (Cl. 317-151) This invention relates to a means for establishing a pulse controlled bi-stable relay to alternately shift between one of two stable states.

In the past without using electronic control means to convert a pulse input to operate a two stage counter so that each pulse constructed relays with rotating armatures mechanical latch mechanisms andthe like.

A principal object of this invention is to provide a single relay of conventional design with a novel resistance capacitance circuit to enable the relay to pickup and re- Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawing in which similar characters of reference represent corresponding parts in each of the several views.

' In the drawings:

The single figure is a schematic view of the preferred embodiment of the invention.

Referring now to the drawing there is shown a relay A of conventional design having a solenoid 13 which operates two or more sets of spring return transfer points 14. The armature 15 of one set of points 14 is arranged to engage a contact 17 when the solenoid is unenergized andv engage a Contact 16 when energized. It is common in such relays that the solenoids require current of at least a predetermined value to cause their contacts to transfer to picked up condition, but after transferring current of substantially less value will hold the armature in the picked up condition.

In this invention means are provided to regulate the current values to cause the relay armature to pickup, hold and drop out in response to a pulse input. For convenience the current Value necessary to pickup the armature will be hereinafter referred to as pickup current and the current value necessary to hold the armature, but insufficient to pickup the armature, will be referred to as holding current. Current value below holding current is i referred to as drop out current.

A source of direct current B of a predetermined voltage is supplied for relay A from a positive terminal 21 and negative terminal 22. The solenoid is connected through a resistor 23 to terminal 21 and through a resistor 24 to terminal 22. The resistance values of resistors 23 and l 2,922,086 ce Patented Jan. 19, 1960 24 and solenoid 13 are selected to provide bias current through the solenoid at the holding value. Resistor 24 is of substantially lower value than resistor 23 and' is bypassed by a condenser 25, of relatively high value, in the range of 5 mfd. or better, so the circuit will allow a greater voltage swing when subjected to changing current to assist in bringing current through the solenoid to the pickup value when a momentary pulse of pickup current is applied through solenoid 13. Resistor 23 is suiciently high so when the potential is first applied, although current through resistor 24 will momentarily be bypassed through condenser 25, the relay armature 15 will not pickup.

The positive side of solenoid a spring urged open push button circuit breaker 26 to armature 15 and through a high capacity value condenser 27, preferably at least l 13 is connected through control switch and may be manually actuated or remotely controlled by a control relay (not shown).

Contact 17 is connected through a resistance 28 to the positive terminal 21 and contact 16 is connected through g al resistance 29 to negative terminal 22. By this arrangement when therelay armature 15 is dropped out condenser 27 is charged through resistance 28. While relay A is in dropped out condition and when switch 26 is closed the condenser 27 then discharges through solenoid 13 to bring the current up to pickup value which causes relay A to pickup. When armature 15 is picked up condenser 27 is discharged or bled olf through resistor 29. Resistance 29 is of high enough value so while armature mentarily offers low enoug noid and bring the solenoid current down to drop out value.

In operation when the electrical power source B is first connected to terminals 21 and 22 the armature -15 remains in dropped out position because the instantaneous current represented by the voltage supply B across the series network resistor 23 and solenoid 13 remains less than the pickup current. l

While armature 15 is in drop out position condenser 27 is charged to power Source B potential through resistance 28. When circuit breaker 26 is momentarily closed there is an immediate discharge of condenser 27 to send additional current through circuit breaker 26 to solenoid 13 to complement with the holding or bias current current through solenoid 13 to the pickup current value. The sudden change of current is also seen by condenser 25 which permits a greater voltage swing to assure a pulse of suicient current to pickup armature 15.

cient to keep the relay current to below pickup value and the condenser 27 at the solenoid potential while circuit breaker 26 is closed. Then when circuit breaker 26 is opened condenser 27 is charged to supply B potential through resistance 28.

It can thus beseenthat repetitive opening and closure of circuit breaker 26 will cause armature 15 to oscillate between the pickup and dropout position.

It has been found in one: particular relay having 1600 Y ohms DSC. solenoid resistance 20 ma. pickup current was required and 6 ma. holding current. With this relay, for example, it was ,found that a power source Bof 125' volts, resistors 23, 28 and 29' of 10,000 ohms each, resistor Zflcf 2,000 ohms, condenser 27' y1 nfd. and condenser 2S,- 20 mfd. was a satisfactoryl combination of relative values for the component parts.y With this combination of values with switch 26 open there is approximately 10 ma. bias current across solenoid `13. when switch Z6 is closed while the relay is inV dropped out conditionL there is substantially more Vthan 20l'rna'. across solenoid 1.3"fr'om discharge of condenser 27 which causes' the relay to pickup. Then after the discharge of condenser 27 the current-drops to ma. When switch 26 is then open the currentfalls to 10ma. andiwhen again'close'dthere'is a momentary shunt 'across the solenoid 13 through condenser 27 which drops the current below 6 ma.Y so the relay drops out'. Then after the relay drops out the current rises to about 8 or 9 ma. until the switch 27 is again open wherein the current raises to 10 ma.

Many transfer points 14 may be employed in mechanically latched relationship withv relay A. Eachv relay transferpoint 1.*4'may be used to directly operate motors, generators, electronic equipment and the like. An example of vone application of theV invention is'in an installation where it is desired to have a push button switch arranged to operate ay motor so that when the switchvis'pushed the motor lwill start and when pushed again will stop and so on repetitively. Another application Where the device is useful is in combination with electronic control devices having a pulse output whichcan close switch 26by solenoid control. f

While therehas'been described a preferred embodiment of the invention, it is understood that certainemodiiications and changes may be practiced as limited only by the scope of the appended claim.

It isV claimed:

In combination a relay of the type having transfer pointsY including a solenoid actuated larmatureV alternatively engageable with first and second contact points; said armai ture spring urged in a rst position in contact with the first contact point andmovable to a second position `in contact with the second contact point when the solenoid of the relay is energized by current above a flirst value and operable to maintain the second position until the current through the solenoid drops below a second value which is less than the first current value; biasing meansV to energize said relay with current above said second value and below said stval'uefsaid biasingm'eansincluding a first resistance element -serially connected between one input terminal of'the solenoid of the relay and-a iirstv terminal of a power source for 'the relay; a second resistance' element serially connectedto a second terminal of the solenoid of'the relay arid to a second terminal of the power source for the relay;v and relay controll means to raise the current through the solenoid of the relay above said iirst value and to lower the current through thev solenoid of the relay belowY said second value;rsaidtrelay control means including said transfer points, a condenser, a vthird resist- Y ance means, 'a' fourth resistance means and a circuit breaker; said circuit breaker connecting said condenser serially with the second terminal of the power source and the Vfirst 'terminalfof the solenoid of the relay when the circuit breaker is in the closed condition of operation; said' third resistance means connected to the first terminal of said power source and the iirst contact point of said transfertpoints; said fourth resistance means connected to the second terminal of said power source andthe second contact point of said relay transfer point; said' armature of said relay transfer lpoints connected to saidcircuit breaker and said condenser to connect said third resistance means'to said condenser when said armatur'eis in the iirst position of operation to charge said condenser through said third resistance means and to connect r`saidjfourth resistance means across said condenser to` 'discharge said condenserwhen said armature is in'the second'posit'ion of operation.

References Cited in the file of this patent UNITED STATES PATENTS- Lorenz Sept. 25, 1956 2,788,473 Breckman Apr. 9, 1957

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