US2935658A

US2935658A - Self-stepping reversible relay chain

Info

Publication number: US2935658A
Application number: US519776A
Authority: US
Inventors: George D Perkins
Original assignee: Bell and Howell Co
Current assignee: Bell and Howell Co
Priority date: 1955-07-05
Filing date: 1955-07-05
Publication date: 1960-05-03
Anticipated expiration: 1977-05-03

Description

May 3, 1960 G. D. PERKINS SELF-STEPPING REVERSIBLE RELAY CHAIN Filed July 5, 1955 United States Patent C v 2,935,658 sELii-srEPPING REVERSIBLE RELAY CHAIN George D. Perkins, Duarte, Calif., assigner, by mesne assignments, to Bell & Howell Company, Chicago, Ill., a corporation of Illinois Application July `5, 1955,.Serial No. 519,776

7 Claims. (Cl. 317-140) This invention relates to aself-stepping relay chain in which the relays operate insuccessionin response to one condition of operation and in which the relays release in reverse succession in response to another condition of operation.

Sequential operation of a stepping switch or of a relay chain is required in many circuits, such as those employed in data handling or in control apparatus. Stepping switches are ordinarily employed to provide such operation, but they are subject to the disadvantage of relatively slow operation and they wear out more rapidly than relays due to the relatively complex mechanical action which -is required in a stepping switch. In some instances relay chains have been employed to provide a stepping action, but such arrangements are ordinarily of complex design and cumbersome.

In accordance with the present` invention, a simplified self-stepping reversible relay chain is provided by ernploying the contacts of the respective relays to energize the relay windings in sequence and cause relays to operate in succession, by employing resistance in the circuits for holding the respective relays, with the resistance being proportioned to provide a holding current which is slightly greater than the minimum required for the respective relays, and by applying a reverse current through the respective relay windings Vin reverse sequence in order to cause the relays to release in reverse succession.

The invention is explained in detailwith reference to the single figure of the drawing.

The relay chain comprises a plurality of relays 19 to 14., Each of the relays 10 to 14 comprises a step in the relay chain. Each of the relays 10 to 14 has a single winding` for operating the relay. Each relay except the first and the last in the chain has first and second sets of contacts which are open and third and fourth sets of contacts which are closed when the relay is in a released condition, with eachset of contacts having one movable contact and one fixed contact. The second set of contacts is employed in the holding circuits for the respective relays, and it is desirable that the second set of contacts close before the third set of contacts open when the relay changes from aV released to an operated condition. The first relay 10 of the chain has the first, second and third sets of contacts and the last relay 14 of the chain has the second, third and fourth sets of contacts.

A first source of potential 16 and a second source of potential 18 provide current for operating and releasing the relays. Current from the source of potential 16 is applied to the relay chain through a switch 20 and the relays operate in succession from left to right when the switch is closed. The source of potential 18 is applied to the relay chain by a switch 22, and the relays release in reverse order from right to left upon closure of the switch 22. Only one of the

switches

20 and 22 should be closed at one time.

The winding of the Erst relay 10 of the chain is con- ICC 2 nected through its third set of contacts to the switch 20. The windings of the other relays are connected to the switch 20 through the third set of contacts of the respective relays and the rst set of contacts of the next preceding relay in the chain.

Resistors 24 are connected between the movable contact of the second set of contacts of each relay and the negative terminal of the source of potential 16 to provide a holding current for causing the respective relays to remain in an operated condition until they are released by a reverse current from the source of potential 18. The resistors 24 are proportioned to provide a holding current which is slightly greater than theminimum holding current required for the individual relays. This provides reliable holding action, yet the low holding current makes it easy to release the relays by applying a reverse current through their windings. That is, the low holding current permits faster releasing action on the part of the relays'. v

Resistors 26 are coupled between the movable contact of the second set of contacts and one contact of the fourth set of contacts of the successive pairs of relays from left to right and between the movable contact of the second set of contacts of the last relay of the chain and the switch 22. The resistors 25 and the associated relay contacts are connected between. the serially connected source of potential 18 and switch 22 and the windings of the respective relays to provide a reverse current through the relay windings which causes them to release when the switch 22 is closed. The resistors are proportioned to provide the desired reverse current.

Depending upon the direction in which the relay chain is to step, either the switch 2'0 or the switch 22 is closed to initiate the desired stepping action. The switch remains 'closed until the desiredfnumber of steps have been eiected, and then it is opened to cause the relays which are then in an operated condition Vto remain in that condition.

Y If all of the relays are in a released condition as illustrated in the drawing, the rst ltwo relays maybe operated by closing the switch 20 longenough to permit current to ow through the third vset of contacts of the first relay- 10 to operate the first relay and through the first set of contacts of the operated first relay and the third set of contacts of the second relay 11 to operate the second relay. The relays. 10 and 11 are held in an operated condition by the second set of contacts of each of these two relays and by the resistors 24 which are connected between these sets of contacts -andthe negative terminal of the source of potential 16.

In order to cause the two relays 10 and 11 to step in the reverse direction, the switch 22 is closed. This causes a current from thesource of potential 18 to ow through the fourth set of contacts of the relay 12, and through the resistor 26 and the second set of contacts of the relay 11 to provide a reverse current through the winding of the relay. This causes the relay 11 to release, and then a reverse current is applied through the fourth set of contacts of the relay 11, the resistor 26, and the second set of contacts of the relay 10 to the winding of the relay 10 to cause this relay Vto release.

Ordinarily the sources of potential 16 and 18 are direct current sources. However, they may provide pulse signals. Such pulse signals will cause theapparatus to function in the same manner as described above provided the duration of each of the pulses is equal to or larger than the time required for one of the relays to operate. 1

The relay chain may be employed to perform various functions. As illustrated in the drawing, a fifth set of contacts may be provided on the respective relays, and

th'esecontactsmaybeemployed to connect or disconnect individual -input circuits to a common line or load 2S.

In one embodiment of the invention, the following circuit constants Were employed:

Withv such an arrangement the respective relays required approximately eight milliseconds per relay to operate upon' closure of the switch 20, and the respective relays required approximately three milliseconds per relay to release upon closure of the switch 22.

The speed at which the Yrelays operate and release is determined by.- .the characteristics of the relays, the voltage offthe sources of potential, and the values of the

resistors

24 and 26. I

The

resistors

24 and 26 which are employed in conjunction with the respective relays serve the dual functions of `,decreasing the time required to release the respective relays and decreasing the amount of power required Lto operate the relay chain.

Although the

mechanical switches

20 and 22 have been illustrated in, thedrawings, it will be apparent that any desired switching arrangement may be employed for applying the Sources of potential to the relay chain. By way of example, an electronic switching arrangement may be employed if desired.

The five relay chain shown in the drawings is merely illustrative and any desired number of relays may be employed.

I claim:

1. A self-stepping reversible relay chain comprising a plurality ofzrelays with each relay having a single winding for operating the relay and having a plurality of sets of contacts which are actuated by operation and release of the relay, means including contacts of the relays for energizing the respective relay windings in succession so that the relays operate in successive steps, means including a resistor for each relay providing a circuitffor holding the respective relays in an operated condition, with each resistor being proportioned to provide a holding current which is slightly greater than the minimum required fortheA respective relays, and means including contacts of the relays for applying a reverse current through the respective relay windings in reverse succession to cause the relays to release in reverse succession.

2. A self-stepping reversible relay chain comprising a t plurality of relays with each relay having a single winding for operatingthe relay and having a plurality of sets of contacts which are actuated by operation and release of the relay, means including contacts of the relays for energizing the respective relay windings in succession se that the relays operate in successive steps, means providing a circuit for holding the respective relays in an operated condition, and means including contacts of the rela-ys for applying a reverse current through the respective relay windings in reverse succession to cause the relays to release in reverse succession.

3. A self-stepping reversible relay chain comprising a plurality of relays With eachl relay having a Winding for operating the relay and having a plurality of sets of contacts which are actuated by operation and release of the relay, first and second sources of potential, first switching means coupled between the first source of potential and the relay windings for energizing the respective relay windings insuccession so that the relays operate in successive steps when the 'first switching means is actuated, first resistance means coupled between a set of contacts of each relay and the first source of potential for holding the respective relays in an operated condition after they have been :energized with current from the first source of potential, and second switching means and second Vresistance means coupled between the second source of potential and the relay windings for applying a -reverse current through the respective relay windings in reverse succession when the second switching means is actuated so that the relays release in reverse succession.

4. A self-stepping reversible relay chain comprising a plurality of relays with each'V relay having a winding for operating the relay, each relay except the first and the last in thechain having first and second sets of contacts which are open and third and fourth sets of contacts which are 'closed when theV relay is released, the first relay of the chain having the first, second and third sets of contacts, and the last relay of the chain having the second, third' and fourth sets of contacts, firstl and second sources of potential, switching means including the first and third sets of contacts coupled between the first source of potential and the relay windings for energizing the respective relay windings in succession so that the relays operate lin successive steps, and switching means including the'second and fourth sets of contacts coupled between the second source of potential and the relay windings for applying current through the respective 'relay windings in reverse succession, with the current from the second source of potential flowing in the QPPOSite direction to that provided by the first sourceA of potential so that the relays release'in reverse succession.

5. A self-stepping reversible relay chain comprising a plurality of relays with each relay having a winding for operating the relay, each relay except the first and the last in the chain having first and second sets of contacts which are open and third and fourth sets of contacts which are closed when the relay is released, the first relay of the chain having the first, second and third sets of contacts, and the last relay of the chain having the second, third and fourth sets of contacts, a first source of potential, a second source of potential, means connecting the winding of the first' relay of the chain through its third set of contacts to the first source of potential, means connecting the windings ofthe other relays to the first source of potential through the third set of contacts ofY the respective relays and the first set of contacts of the,

next preceding relay in the chain, first resistance means coupled between the second set of contacts of each relay and the first source of potential for holding the respective relays in an operated condition after they have been energized with current from the first source of potential, second resistance means coupled between the second and fourth sets of contacts of the successive pairs of relays and between the second set of contacts of the last relay of the chain and the second source of potential, and means including the fourth sets of contacts of the relays and the second resistance means coupled between the second source of potential and the relay windings for applying a reverse current through the respective relay windings in reverse succession, so that the relays operate 1n succession in response to current from the first source of potential and release in reverse succession in response to current from the second source.

6. A self-stepping reversible relay' chain comprising a plurality of relays with each relay having a winding for operating thel relay, each relay except the first and t'ne last in the chain having first and second sets of contacts which are open and -third and fourth sets of contacts which are closed when the 'relay is released, with the second set of contacts closing before the third set of contacts open when the relay changes Vfrom a released to an operated condition, the first relay .of Ithe chain having the first, second and third sets of contacts, and the last relay of. the chain having the second, third and fourth sets of contacts, a first source of potential having a first switch connected in serieswith it, a second source of potential having a second switch connected in series with it, means connecting the winding of the flrst relay'l of the chain through its third set of contacts to the vserially connected,

first source of potential andfirst switch, means connecting the windings of the other relays to the serially connected rst source of potential and irst switch through the third set of contacts of the respective relays and the rst set of contacts of the next preceding relay in the chain, first resistance means coupled` between the second set of contacts of each relay and the first source of potential for holding the respective relays in an operated condition after they have been energized with current from the rst source of potential, second resistance means coupled betweenthe second and fourth sets of contacts of the successive pairs of relays and between the second set of contacts of the last relay of the chain and the serially connected second source of potential and second switch, and means including the fourth sets of contacts of the relays and the second resistance means coupled between the serially connected second source of potential and second switch and the relay windings for applying a reverse current through the respective relay windings in reverse succession when the second switch is closed, so that the relays operate in succession when the first switch is closed Vand release in reverse succession when the second switchY is closed. v

7. A self-stepping reversible relay chain comprising a plurality of relays with each relay having a winding for operating the relay, each relay except the first and-the last in the chain having first and second sets of contacts which are open and third and fourth sets of contacts which are closed when the relay is released, with each set of coni 6 series with it, means connecting the winding of the irst relay of the chain through its third set of contacts to the Vserially connected first source of potential and tirst switch,

means connecting the windings of the other relays to the serially connected irst source of potential and first switch through the third set of contacts of the respective relays and the tirst set of contacts of the next preceding relay in the chain, rst resistance means coupled between the movable contact of the second set of contacts of each relay and the first source of potential for holding the respective relays in an operated condition after they have been energized with current from the irst source of potential, second resistance means coupled between the movable contact of the second set of contacts and one contact of the fourth set of contacts of the successive pairs of relays and between the movable contact of the second set of contacts of the last relay of the chain and the serially connected second sourceV of potential and second References Cited in the tile of this patent Y UNITED STATES PATENTS 1,838,961

Robinson Dec. 29, 1931 2,008,909 Hershey July 23, 1935 Y2,140,601 Serriere Dec. 20, 1938 ,2,236,276 Stewart Mar. 25, 1941 Y2,593,578 Liberg Apr. 22, 1952