US2552614A

US2552614A - Time-delay relay mechanism

Info

Publication number: US2552614A
Application number: US605416A
Authority: US
Inventors: John S Baker
Original assignee: Cook Electric Co
Current assignee: Cook Electric Co
Priority date: 1945-07-16
Filing date: 1945-07-16
Publication date: 1951-05-15
Anticipated expiration: 1968-05-15

Description

May 15, 1951 J. 5. BAKER TIME-DELAY RELAY MECHANISM 3 Sheets-Sheet 1,

Filed July 16, 1945 INVENTOR. Jbhm fificz/mr 4% y 1951 J. s. BAKER 2,552,814

TIME-DELAY RELAY MECHANISM Filed July 16, 1945 5 Sheets-Sheet 2 INVENTOR.

Exit/57L 5561/5877 v 14124, 1% .1 M4 s.

Patented May 15, 1951 UNITED STATES PATENT OFFICE TIME-DELAY RELAY MECHANISM John S. Baker, Chicago, Ill., assignor to Cook Electric Company, Chicago, 111., a corporation of Illinois 8 Claims.

This invention relates to electrical time delay apparatus and more particularly to electrical time delay relays for producing relatively prolonged time delay intervals, it being an object of the invention to provide improved time delay apparatus of the character indicated.

t is a further object of the invention to provide improved electrical time delay relays for producing a plurality of time delay intervals.

It is a further object of the invention to provide an improved time delay relay.

Electric time delay relays are small units having coils or windings to actuate an armature which in turn functions to open or close contacts associated therewith. Time delays are produced in the operation of the contacts, whether opening or closing, by well known means which commonly comprise magnetically coupling shortcircuited windings or slugs with the relay exciting windings which delay the increase or decrease of current in the relay windings according to well known laws, such short-circuited windings usually being placed on the same magnetic core as the exciting windings. The relay armature is attracted to actuate the contacts only when the current through the coil reaches a certain value. Thus by varying the time necessary to reach this value the time delay of the relay is varied. Prior expedients to vary the time delay involve increasing the inductance of the relay windings without substantially increasing the resistance, and apparatus constructed according to such well known principles are capable of only producing relatively short time delays. Moreover, apparatus constructed according to these principles becomes bulky when relatively prolonged time delays are desired, and consequently, it is not satisfactory where design reuirements dictate a unit of small size. Accordingly, it is a further object of the invention to provide an improved electrical time delay relay for producing a relatively prolonged time delay interval that is small in size, efiicient in operation and simple to use.

In carrying out the invention in one form, time delay apparatus is provided which comprises a plurality of time delay circuits adapted to be energized in succession and contacts associated with each of said plurality of circuits. The contacts associated with a particular circuit are adapted to be energized by that circuit after a time delay, and each circuit is energized through a pair of contacts operated by a preceding circuit. More particularly, the time delay apparatus comprises a first pair of time delay circuits having an armature operable thereby with limits or" movement, a second pair of time delay circuits having an armature operable thereby also with limits of movement, resilient means resisting operation of the first armature, and resilient means resisting operation of the second armature. Energization of the first one of the first pair of time delay circuits operates the first armature against the first resilient means to a position intermediate its limits of movement. First contacts are adapted to be actuated by the first armature in its intermediate position to energize the first one of the second pair of time delay circuits and energization thereof operates the second armature against the second resilient means to a position intermediate its limits of movement. Second contacts are adapted to be actuated by the second armature in its intermediate position to energize the second one of the first pair of time delay circuits to further operate the first armature against the first resilient means to one limit of its movement. Third contacts are adapted to be operated by the first armature at this limit of movement to energize the second of the second pair of time delay circuits to further operate the second armature against the second resilient means to one limit of its movement. Contacts for controlling an external circuit are arranged to be operated by the second armature at this limit of movement.

For a more complete understanding of the invention, reference should now be had to the accompanying drawings in which:

Figure 1 is a front elevational view of a relay embodying the invention;

Fig. 2 is an end elevational view partially in section of Fig. 1;

Fig. 3 is a somewhat enlarged sectional eleva tional view taken substantially along lines 33 of Fig. 2;

Fig. 4 is a sectional elevational view taken substantially along lines 4-4 of Fig. 2;

Fig. 5 is a sectional elevational view taken substantially along the lines 5--5 of Fig. 3;

Fig. 6 is an enlarged view taken substantially along the lines 66 of Fig. 3 with circuits and connections thereto shown diagrammatically;

Fig. 7 is a schematic wiring diagram showing the manner of operation of the relay;

Fig. 8 is a similar wiring diagram of another embodiment of the invention;

Fig. 9 is a schematic diagram showing a further manner of obtaining a time delay;

Fig. 10 is a schematic diagram showing another manner of obtaining a time delay, and

Fig. 11 is a schematic diagram showing a still further manner of obtaining a time delay.

Referring more particularly to the drawings, the invention is shown embodied in a relay i including a casing or housing Ii, time delay adjusting means I2 and I3 mounted on one side of the housing, a terminal board [4 mounted on the other side of the housing, and time delay means mounted inside of the housing, as will be more particularly described.

The housing H may be of any desirable form having sufficient rigidity to support the operating elements and may, for example, include a base [6, front and rear side walls ii and i3, and a cover I9. The side walls I! and it are connected by a bottom portion 2! which is received between the ends of the base it and bolted thereto as shown, so that the front and rear walls H and I8 extend upwardly, the time delay adjusting means 52 and I3 extending outwardly of the front side 'wall ii, and the terminal board I l being mounted on the rear wall it. To completely enclose the relay housing, the cover i9 is substantially inverted U-shaped, having ends 22 .and 23 connected by a top portion 24, the ends and top portion being U-shaped in cross section thereby to provide extending

flanges

25 and 25 which are received around the side walls ll and It. The cover IQ is attached to the base is by means of screws 2'! and 28.

Mounted inside of the relay casing H to produce the time delays are two time delay units 29 and 3|, each of which is capable of producing two time delay intervals. Through circuits and contacts to be described, these separate time intervals are added to each other to produce a prolonged time delay.

The time delay unit as is a relay having contacts adapted to be operated by a coil which embodies time delay means within it and includes a frame 32, a coil 33 attached to the frame at one end thereof, an armature 34 pivoted to the frame at the other end and arranged to be attracted by the coil when energized, and two series of contacts 3? and 33 mounted on the frame. The armature 34 is provided with a pair of arms. 35 and 38 (Fig. extending along the sides of frame 32 and provided with right angularly extending

tongues

51 and 58 for actuating the contacts. The series of contacts 3'! comprises the contact springs 39, 4i, 42, t3 and ta, which are separated from each other by suitable insulators the assembly of contact springs and insulators being attached to the relay frame by means of bolts 45. Each contact spring is provided with an arcresisting contact whereby external circuits are either completed or broken when armature Si l is attracted by coil 33. The contact springs 39, i2 and M are arranged to be relatively stationary, whereas contact springs ii and 43 are provided with insulating nipples ll and 48 respectively, by means of which these contact springs are operable by the armature 3d. The contact spring 4! is provided with two contacts as shown (Fig. 3)

and cooperates with the contact spring 39 to form an initially closed circuit and further cooperates with contact spring 42 to form an initially open circuit. The series of contacts 38 comprises the

contact springs

49, 5!, and 52 separated from each other by means of suitable insulators 53 and attached to the frame 32 by means of bolts 54. The contact springs 45, Si, and 52 are provided with suitable arc-resistant contacts, the contact spring 51 being provided with two contacts .as shown and having an insulating nipple 5t attached thereto for engagement by the tongue 58 (Fig. 4) whereby the contact spring 5i cooperates with contact spring 52 to form an initially open circuit, and further cooperates with contact spring (it to form an initially closed circuit.

The two series of contacts 3i and 38 are separated from each other by means of an insulating spacer 55. The armature 34 is pivoted to the relay frame 32 by an attaching plate 55 held to the frame 32 by means of

bolts

55 and 54 which also hold the contact springs to the frame. Lying directly on top of the attaching plate 56, and overlying tongues 57 and 53, are the armature movement resisting springs 59 (Fig. 3) and 6% (Fig. 4). The armature resisting springs 59 and Bi bias the armature to its initial or inoperative position and resist any changes therefrom when it is attracted by energizing coil 33. Movement of the armature is also resisted by the

resilient contact springs

4 I, 43 and 5!, as shown.

The coil 33 comprises an iron core 62 and four windings (53, 6d, and 66 (Fig. '7). The winding 63 is connected to terminals ill and 63 (Fig. 3) and the winding 64 is connected to terminals 69 and 'H (Fig. 4) whereby these two windings may be energized from an external source of current. The windings 65 and 5t associated respectively with windings 63 and 84 are short-circuited on themselves, whereby time delays are produced in the building up of the magnetic field through the iron core 62. The number of turns in and the resistance of the coils 63 and 84 may have suitable values to produce the necessary attractive force to operate the relay contacts, and the number of turns in and the resistance of the

coils

65 and 68 may have suitable values to produce the necessary time delays desired, as is well understood by those skilled in this art.

The time delay unit 3| similar to the time delay unit 29 is a relay having contacts adapted to be operated by a coil embodying time delay means within it, and includes a frame ii, a coil '53 attached to one end thereof, an armature l4 pivoted to the other end thereof, and two series of contacts 15 (Fig. 3) and 76 (Fig. 4) insulated from each other by an insulating spacer H34 (Fig. '6). The armature 74 is pivoted to the frame #2 by a shaft Ti so as to be attracted by coil #3 when energized, the shaft being held to the frame 72 by means of a plate 18. A pair of arms tend from armature 14 along each side of frame '12, the arms being provided with lugs '13 and 33 for actuating the contacts. The series of contacts '15 comprises the contact springs 32, 83, 34, and 85 separated from each other by suitable insulators 81 and attached to the frame 72 by means of bolts 88. Each of the contact springs is provided with an arc-resistant contact as shown whereby xternal circuits may be completed or broken by actuating contact springs 83 and 85 through movement of armature l4, insulating nipples 89 and 9| being attached respectively to contact springs 83 and 85 for this pur- 5, pose. The contact springs 82, 84 and 80 are arranged to remain relatively stationary while the contact springs 83 and 85 are movable, the contact spring 83 being provided with two contacts (Fig. 3) whereby it cooperates with the contact spring 82 to form an initially closed circuit, and with the contact spring 84 to form an initially open circuit.

The series of contacts I6 includes the contact springs 92, 93, 94, 95 and 96 separated from each other by means of insulators 91 and attached to the frame I2 by means of bolts 98. Each of these contact springs is provided with an arc-resistant contact whereby through actuation by the armature I4 external circuits may be completed or broken as desired, the contact springs 92, 94 and 96 being adapted to remain relatively stationary while contact springs 93 and 95 respectively are provided with insulating nipples 99 and Isl, which are engaged by the armature tongue "I9 to move these contact springs for circuit making or breaking purposes. The contact spring 93 is provided with two contacts as shown (Fig. 4) whereby it cooperates with contact spring 92 to form an initially closed circuit and further cooperates with contact spring 94 to form an initially open circuit.

Lying directly on the attaching plate 88, and overlying tongues I9 and BI of armature I4, are the armature movement resisting springs H02 (Fig. 3) and I03 (Fig. 4) respectively. The springs I02 and I03 are held to the frame I2 by the

bolts

88 and 98 holding the series of contacts I5 and I6 to the frame I2, and resiliently resist movement of armature I4 when coil 13 is energized. The contact springs 93 and 95 bearing against the tongue I9 and the contact springs 03 and 85 bearing against the tongue SI also resist movement of the armature.

The coil "I3 similar to the coil 33, includes an iron core I05 and four windings I06, I01, I and I09 (Fig. '7), the winding I06 being connected to the terminals I I I and I I2 (Fig. 3), and the winding I01 being connected to the terminals I I3 and I I4 (Fig. 4), whereby these windings may be connected to an external source of current. The windings I08 and I09 are short-circuited on themselves to produce time delays in the building up of a magnetic field through the core I05 and consequently in the operation of the armature TM after coils I06 and I0! are energized. The number of turns in and the resistance of windings I08 and I0! are such as to produce a magnetic force of the magnitude desired to attract armature I4, and the resistance and the number of turns in the windings I08 and I09 are such as to produce the desired time delay in connection with the windings I06 and I01 as is well understood by those skilled in this art.

The time delay units 29 and 3| comprise externally excited coils wound on iron cores and short-cijrcuited windings magnetically coupled therewith. It is well known that when a circuit having both resistance and inductance is supplied with a direct current voltage, the current in that circuit increases from zero to a steady state or maximum value according to the law [win-JE varying the values of resistance and inductance, the time necessary for the current in the circuit to build up to any value may be varied. If the ratio R/L is small, the current i increases slowly and if the ratio is large, the current 2 increases at a more rapid rate. While the law for direct current excitation has been given, it will be understood that alternating current may of course be used.

Referring to Fig. 7 where the time delay units 29 and 3| are shown schematically with their windings to be externally energized and their associated short-circuited windings, if the winding I09 is energized, current begins to flow therein dependent on its own resistance and inductance, and also on the resistance and inductance reflected into the circuit by the coupled shortcircuited windings. I08 and I09, according to the law previously set forth. While the current in winding I06 is increasing, there is current flowing in windings I08 and I09 by virtue of the magnetic coupling, but when the current in winding I05 reaches its steady state value the current in windings I08 and I09 is reduced to zero. The time delay between the energization of the winding I06 and the building up of the current therein to substantially its maximum value is the time delay produced by winding I06, and contacts associated with the winding are operated at the end of that time interval.

The winding I01 of time delay unit SI and the windings 03 and 64 of time delay unit 29 are not energized at the time the winding tilt is energized. However, when the winding I0! is energized, a time interval clapses between the energization thereof and the building up of the current therein to its maximum value according to the law set forth. The resistance or the coil the in ductance thereof, as well as the resistance and inductance reflected into the circuit by the shortcircuited windings I08 and I09 enter into producing the time delay as alread pointed out for winding I00. Similar to the time dela unit 3!, there is a time delay between energizing each of the coils 03 and 6 lof the time delay unit .29, and the increase of current therein to its maximum or steady state value, the coupled short-circuiied windings 65 and 6E being provided as part of the time delay means. Through appropriate circuits and contacts operated by the time delay units 29 and 3!, the various coils are energized in succession. The winding I06 is energized first and after the current therein has increased to a certain value, contacts 95 and are closed to energize the winding 63. After the current in winding 93 has increased to a certain value, contacts and M are closed to energize the winding I07. After the current in winding I0? has increased to a certain value, contacts 535 and 80 are closed to energize the winding 94 which, after a time interval, has suflicient current flowing through it to close associated service or like contacts on contact. springs GI and 42. Thus by energizing the various. coils of the time delay units in succession, each succeeding coil being energized by contacts controlled by the preceding coil, a total. delay equal to the sum of the individual time delays is obtained.

As already pointed out, varying the resistance in the circuits of the windings varies the elapsed time. between the energization thereof and the increase of the current therein to its maximum value. Therefore the variable resistors H5 and H5 are associated respectively with the time delay mechanisms EI and 29. The resistor II5 is part of a resistance unit which may be of ant well-known type including a fixed terminal II1 attached to one end of resistor H5, and a movable arm II8 connected to a stationar terminal H9, whereby moving arm II8 varies the amount of resistance II5 included in the circuit, the arm II8 being turned by the adjusting knob I3. The resistor H6 is also part of a well-known resistance unit including a fixed terminal I2I connected to one end thereof and a rotatable arm I22 adapted to move along the resistor I I6 to vary its value. The movable arm I22 is connected to the stationary terminal I23 and is rotatable through the adjusting knob I2.

Referring to Figs. 6 and 7, in order to energize coil I06 a circuit is completed extending from a source of supply, through conductors I24 and I25 to the terminal III and through conductors I26 and I21 to the terminal II2. After current of suflicient value flows through Winding I06, the armature 14 is attracted to close the contacts on contact springs 95 and 96, energizing winding 63 through a circuit extending from the source of supply through conductor I24, conductor I28, terminal 69, through winding 63, terminal 1I, conductor I29, contact springs 96 and 95, conductor I3I, conductor I32, and conductor I26 to the source of supply. When the current in winding 63 rises to th necessary value, the armature 34 is attracted to close the contacts on contact springs 43 and 44, thereby energizing winding I01 through a circuit extending from the source of supply, through conductor I24, con ductor I33, resistor II5, conductor I34, contact springs 43 and 44, conductor I35, terminal II3, through winding I01, terminal II4, conductor I36, conductor I32, and conductor I26 to the source of supply. After a time interval, suificient current flows in the winding I01 to further attract armature 14 to close the contacts on the contact springs 85 and 86 which energizes the winding 64 through a circuit extending from the source of supply, through conductor I24, conductor I28, conductor I30, resistance I I6, conductor I31, contact springs 85 and 86, conductor I38, terminal 68 through coil 64, terminal 61, conductor I39 and conductor I26 to the source of supply. After the current in winding 64 reaches substantially its maximum value the armature 34 is further attracted to close contacts of springs ll and 42 associated with external circuits which experienc the additive time delays produced by each windmg.

To supply power to the time delay units 29 and 3I, as well as to provide connections to external circuits whereby the different time delays available from the time delay units may be made use of, the terminal board I4 is provided with a plurality of terminals I4I, I42, I43, I44, I45, I46, I41, I48, I49, I50, I5I, I52, I53, and I54, each of the terminals being supported by means of a suitable grommet I55. Circuits from the terminals I4I-I52, inclusive, to the contact springs are completed as follows: from terminal I4I, through conductor I55 to contact spring M; from terminal I42, through conductor I51 to contact spring 39; from terminal I43, through conductor I53 to contact spring 42; from terminal I44, through conductor I59 to contact spring 49; from terminal I45, through conductor I6I to contact spring 5I; from terminal I46, through conductor I62 to contact spring 52; from terminal I41, through conductor I63 to contact spring 93; from terminal I48, through conductor I64 to the contact spring 94; from terminal I49,

through conductor I65 to contact spring 92; from terminal I50, through conductor I66 to contact spring 84; from terminal I5I, through conductor I61 to contact spring 83; from terminal I52, through conductor I68 to contact spring 82; from terminals I53 and I54, the conductors I24 and I26 extend respectively for supplying power to the time delay units.

With the foregoing structure in mind, it is believed that the functioning of the invention may best be understood by considering an example of operation. It is assumed that the source of power, which may be a battery I69 (Fig. 7), is connected to terminals I53 and I54 (Fig. 6) through a switch HI, and that external circuits are connected to the various terminals as may be desired. While the source of power I69 has been shown as a direct current source. it will be understood that alternating current may be used without departing from the spirit and scope of the invention. Then, if the switch I1I is closed at any instant, power is supplied to the Winding I06 through its terminals III and H2 and the conductors I25 and I21 already described. At this instant none of the remainder of the windings have any external energization applied to them since the circuits leading to them are open. The current increases through the winding I06 at a rate dependent on the circuit constants as previously indicated and consequently builds up a magnetic field through the core I03, which tends to attract the armature 14. The movement of the armature, however, is resisted by the springs I02 and I03 as well as by contact springs 83, 85, 93 and 95 which bear against the armature through the attached insulating nipples. However, when the current through winding I06 approaches its maximum or steady state value, the armature 14 is attracted sufficiently to move against the force of springs E62 and I03 and the contact springs a small amount sufiicient to close the contacts of contact springs 95 and 96 without closing the contacts of contact springs 85 and 86. This movement of the armature also opens the contacts of the contact springs 92 and 93 and closes the contacts of contact springs 93 and 94, but contact springs 82, 83 and 84 are so positioned that the contacts associated therewith do not have their relative positions changed. The resisting force of the springs I02 and I03, along with that of the various contact springs, is balanced against the attractive force produced by the winding I06. The point of balance, 1. e., where the armature becomes stationary, may be so adjusted that operation of the contacts occurs a fraction of a second after the switch I1I is closed, for example, after a time interval of the order of one-tenth to three-tenths seconds, but since the armature is not completely attracted, all of the contact springs associated therewith are not actuated. However, external circuits connected to the terminals I41 and I48 are closed and external circuits connected to the terminals I41 and I49 are opened after the time delay effected by the winding I06 (the first time delay of unit 3I), since movement of the contact spring 93 effects movement of its contact away from the contact of contact spring 92 and into contact with the contact of contact spring 94.

After the contacts of contact springs 95 and 96 are closed, the winding 63 of the time delay unit 29 is energized through the circuit already described. The current increases through the winding 63 at a rate determined by the associated circuit contacts, and accordingly a magnetic field is built up through the iron core 62 which tends to attract armature 34. Movement of armature 3A is resisted by

springs

59 and 6| as well as of the contact springs ii, Q3 and through attached insulating nipples bearing against the armature. As the current in coil 53 approaches its maximum or steady state value, the armature is attracted with sufficient force to overcome the force of the resisting springs to effectuate closing of the contacts of contact springs 43 and 44. At the same time, the armature 34 opens the contacts of contact springs 39 and M and closes the contacts of contact springs 4i and 42. Other contact springs associated with the time delay unit 29 are positioned so as not to be effected by this initial movement of the armature. The at tractive force produced by the winding 63 is balanced against the resisting force of the springs and the armature becomes stationary when these forces are equal, which condition exists after a movement of the armature sufiicient to operate contacts of contact springs 30, 4| and 42 as well as of contact springs 43 and M. The effect of the resisting force is to delay actuation of these contacts for a period of the order of one-tenth to three-tenths seconds, for example, which time delay is added to the time delay produced by the winding I65. Therefore the external circuits connected to the terminals MI and I42 (contact springs 39 and ll), and terminals ME and Mt (contact springs 45 and 42), are opened and closed, respectively, after a time delay of the order of four-tenths to six-tenths of a second, for example.

Closing the contacts of contact springs c3 and 44 energizes winding lill' through a circuit already described including the resistor i It. With the completion of this circuit, current begins to flow through the winding Hill as well as through the windings I68 and Hi9 which are inductively coupled to the winding Isl by being wound on the same iron core. The current through winding in! increases as determined by the associated circuit constants, and as it increases the ma netic field created thereby through the iron core I95 also increases, and when this current reaches substantially its maximum or steady state value, the armature it is attracted to its final position thereby closing the contact springs 85 and 86. r

Movement of armature 34'- is also resisted in this instance, as in the instance of energizing winding 1%, by the armature resisting springs M32 and 583 as well as by the contact springs as, 85, Q3 and 95, and the time delay between the energization of winding It]? and the closing of the contacts of contact springs 85 and 3% is the result of the attractive force produced by the magnetic field through core 35, and the resisting force produced by the springs Hi2 and its as well as of the contact springs associated with the armature i i. The winding 186 is still energized and thus the final movement of armature M is the result of the combined efforts of windings i936 and till. This final movement of the armature is in addition to closing the contacts of contact springs 85 and 8E, closes the contacts of contact springs 83 and as well as opening the contacts of contact springs 82 and 53. The time delay produced through the energization of winding H3? is added to the time delays produced by windings i515 and 63, and, therefore, external circuits connected to the terminals l5! and E52 (contact springs and 533) and i521 and iii! (contact springs 8 3 and 83) will be actuated after a time delay of seventenths to nine-tenths of a second (the time delay occasioned by winding It'll being of the same order of magnitude as that produced by winding Hi6). Through the use of the variable resistor H5, variations in the time delay produced by winding Hi? of the order of one-tenth to threetenths seconds, for example, may be realized.

Closing the contact springs ad is completes the energizing circuit for winding 6 1 through a circuit already described including the variable resistor 1 iii, and with the completion thereof current begins to flow therein and increases at a rate which is dependent on the associated circuit constants according to the law set forth. As current through winding 64 increases, the magnetic field created by it through core 62 also increases and attracts the armature 3A to its final position, movement thereof being resisted by the armature resisting springs 59 and SI as well as by the contact springs 4| and t3 similar to the case of energizing the winding 83. The winding 63 is still energized and thus the final movement of armature 34 is the result or" the combined efforts of windings G3 and c4. When the current through winding approaches its maximum or steady state value, also with a time delay of onetenth to three-tenths of a second, for example, the attractive force produced by the magnetic field in core 62 overcomes the spring resisting force and the armature is moved to its final position to close the contacts of contact springs 5i and 52 and to open the contacts of contact springs ts and 5!. The time delay, in actuating the contact spring 5! to open and close the circuits associated therewith, is added to the time delays produced by windings t3, Hi5 and Hill and hence external circuits connected to the terminals i i and 145, and M5 and I46 are opened and closed respectively after a time delay of the order of nine-tenths to one and two-tenths seconds, for example. Through variations in the variable resistor I :6, the time delay produced by the winding 53 may be varied from one-tenth to three-tenths of a second, for example.

The two time delay units 29 and 3| are provided with four armature actuating coils, two of which are associated with each time delay unit. After the first circuit is energized, contacts are closed by it after the time delay within the coil necessary to build up its current to substantially a maximum or steady state value has been realized. Thereafter each winding, after the time delay which it produces, closes contacts energizing a succeeding coil also producing a time delay. Thus the windings are energized successively and the time delays of each winding are added to those of the remaining windings to produce a total time delay which is the sum of the individual time delays.

Referring to Fig. 8, there is shown a circuit diagram of another embodiment of the invention having substantially the same basic features as the embodiment already described, but in which a difierent arrangement is empoyed for varying the time delays produced by the individual windings. The second embodiment also includes two time delay units, each of which embodies two coils adapted to be externally energized along with short-circuited windings magnetically coupled therewith to assist in producing the desired time delays, and contact springs adapted to be operated by the various windings so as to energize the windings in succession and thereby add the time delays to each other.

The first of these time delay units comprises an iron core I12 having the windings I13 and I14 arranged on it for external energization and the short-circuited windings I15 and I18. Associated with windings I13 and I14 are contact springs I11, I18, I19, and I89 which are provided with arc-resistant contacts to close circuits energizing certain of the time delay windings. The secnd time delay unit is substantially identical with the first and includes an iron core I82, with windings I83 and. I84 arranged on it to be externally excited, and the short-circuited windings I85 and I86. Associated with this time delay unit are contact springs I81 and I88 which are provided with arc-resistant contacts for energizing one of the time delay circuits. In order to vary the time delay effected by the windings I13 and I83 and the coupled short-circuited windings, a resistor I89 is connected so as to be in series with each of windings I18 and I83, and to vary the time delay produced by the windings I14 and I84 along with the coupled short-circuited windings, a resistor I9! is connected so as to be in series with windings I14 and I84. The switch I92 and a source of current supply, which may be a battery I93, are arranged to energize the windings of the time delay units.

The coil I13 is energized through a circuit extending from the source of current supply I93, through switch I92, conductor I94, variable resistor I89, conductor I95, winding H3, conductor I96, conductor I91, and conductor I98 to curr nt source I93. The remaining externally excited time delay windings are energized through contacts controlled by preceding windings and hence remain unenergized in the first instance. The current through winding I 13 increases dependent on its own resistance and inductance, the resistance and inductance reflected into the circuit by the coupled short-circuited windings I15 and I16, and the resistance of the resistor I89, according to the law as set forth for the first embodiment. When this current reaches substantially its steady state or maximum value, only the contacts of contact springs I 11 and I18 are closed to energize succeeding winding I83. Varying the value of resistor I89 of course varies the time delay which elapses before the contact springs I11 and I18 are actuated by winding I13.

Closing the contacts of contact springs I 11 and I18 energizes winding I83 through a circuit extending from the source of supply I98, switch I92, through conductor I94, resistor I89, conductor I99, winding I83, conductor 28I, contact springs I 11 and I18, conductor 282, conductor I91, and conductor I 98 to source of supply I93. With the completion of this circuit, the current through winding I83 increases dependent on its own resistance and inductance, the resistance and inductance reflected into the circuit by the coupled'shortcircuited coils I85 and I36, and the resistance of resistor I89. When this current reaches substantially its steady state or maximum value, the contact springs I81 and I88 are actuated to energize winding I14. The resistor I89 being variable, the time delay produced by winding I83 may be varied. However, since the resistor I89 also varies the time delay in winding I13, when this resistor once has its value selected, it introduces virtually the same variation in time delay into both the windings i 13 and I83.

Closing the contacts of contact springs I81 and I88 energizes winding I14 through a circuit ex tending from source of supply I 93, through switch I 92, conductor I94, resistor I9I, conductor 283, winding I14, conductor 284, contact springs I81 and I88, conductor 295, conductor 286, and conductor I98 to source of supply I93. After winding I14 is energized, the current begins to build up therein and creates a magnetic field through the iron core I12 in addition to that created by winding I13. The increase in the current is dependent upon the resistance and inductance of winding I14 and the resistance and inductance reflected into the circuit by the coupled shortcircuited windings I15 and I16, and the variable resistance I9I. When this current reaches its steady state or maximum value, the contacts of contact springs I19 and I89 are closed. The time delay, in actuating contact springs I18 and I88, may be varied by varying the value of resistor Closing contacts of contact springs I 19 and I energizes winding I84 through a circuit ex tending from the source of supply I93, through switch I92, conductor I94, resistor I9I, conductor 281, winding I84, conductor 288, contact springs I19 and I88, conductor 2'89, conductor 296, and conductor I98 to the current source I93. After the current flowing through winding I84 has increased to substantially its maximum or steady state value, the contact springs 2| I and 2 I2 are actuated, which may control an external circuit. The time delay in winding I84 is the result of its own resistance and the inductance as well as of the resistance and inductance refiected into the circuit by the coupled shortcircuited windings I and I85, and the resistor I9I. The winding I83 is still energized and thus the contact springs 2H and 2I2 are closed through the combined eiforts of windings I83 and I 84. By varying the resistance of resistor I 9|, the time delay produced by winding I84 may be varied, but since resistor was set to vary the time delay of the winding I14, it produces substantially the same time delay in winding I84. In the second embodiment, as well as in the first one, the various windings of the time delay units are successively energized and the time delay of each winding is added to that of the succeeding windings to produce a total time delay equal to the sum of the individual time delays, contacts being arranged to be actuated by each winding after its time delay.

Figs. 9, 10 and 11 indicate schematically different arrangements for producing time delays within the windings of the time delay units. In Fig. 9 there is shown an iron core 2 I3 having two coils 2I4 and 2I5 wound thereon and arranged to be excited from an external source, and a short-circuited winding 2I6 also wound on core 2 I3 and therefore magnetically coupled to windings 2M and 2I5, the windings 2I4, 2I5 and 2I6 being separately wound. Assuming that winding 2 I4 is energized first, current will build up therethrough dependent on its own resistance and inductance as well as the resistance and inductance reflected into the circuit from the shortcircuited winding 2I6. After the current in winding 2I4 reaches its maximum or steady value, there will be no change in the current flowing, and hence, there will be no current flowing in winding 2I6. Thereafter, when winding 2| 5 is energized, the current therein will increase dependent on its own inductance and resistance, as well as that reflected into the circuit from the winding 2I6. Current flows in winding 2I6 as a result of its also being coupled with winding 2I5, and hence, it produces the same time delay in connection with winding 2I5 as it did in connection with winding 2I4. In this manner a acumen single winding may be. used to produce time delays. in more than. one winding: coupled with it.

Fig. illustrates an arrangement; having an iron core 251,. two externally excitable windings 21 8 and 219, and a. short-circuited'. winding 22!, all three windings being wound together on core 211. In this modification, short-circuited'. wind-- ing 22| acts in. conjunction with, each. of, windings 218 and 249 to: produce time delays, but the interwinding of the windings brings them. closer together and. creates a state of more effective coupling.

In Fig. 111 there is shown. an arrangement for producing time delays in coils having aniron core 222,. two windings 223 and 2 24 interwound with each other, and a conducting slug 225 which may be of; copper or some other good conductingmaterial. The copper slug 225 is continuous and may, for example, be a cylindrical slug surrounding core 222, and accordingly forms a shortcircuited path for currents flowing therein, the slug accordingly producing a time. delay in the build-up of the currents through windings. 223 andv 22-4.

Without further elaboration, the foregoing will sofully explain the gist of. my invention that others may, by applying current. knowledge, readily adapt the same for use under varying conditions of service, without eliminating certain features, which may properly be said to constitute the essential items of novelty involved, which items are intended to. be defined and secured to me by the following claims.

I claim:

1. Time delay apparatus comprising, a pair of coils arranged on a core, said coils being separately and successively energizable and. being so wound as to produce, when energized, cumulative excitation of. said core, means for conducting energizationto. one of said pair of coils, time delaycircuit meansarranged on said core and being magnetically coupled with said coils, an, armature actuatable by said pair of coils, said armature having one position effected by energization of one of said pair of: coils and having another position effected byenergization of both of said pair of coils, resilient means resisting actuation of said armature, said resilient means having suificient stiiiness to permit actuation of said armature only to said one position after energization of said one coil, contacts actuatableby said armature inmoving to said one position, circuit means made effective by the actuation. of said. contacts for conducting energization to the other of said pair of coils, said resilient means further having such stiffness to permit actuation of said armature to said other. position after. energ-ization of said other coil.

2. Time delay apparatus comprising, a pair of coils arranged on a core, said coils being separately and successively energizable and being so wound as to produce, when energized, cumulative excitation of said core, means for conducting energization to one of, said pair of coils, time delay circuit means arranged on said core and being magnetically coupled with said. coils, a first armature actiatable by said pair: of coils, said first armature having one. position efiectcd by energization of one of said pair of; coils and having another position effected by energization of both of said pair of coils, resilient means having sufficient stifiness to permit actuation of said first armature only to. said one position; after energization of said one coil, firstv contacts actuatable by said armaturezin moving to saidone position, a

third coil arranged on a further core, timedelay circuit. means. mounted on said further core and being magnetically coupled with said third coiI, a second armature actuatable by said third coil when energized, circuit means connecting said first contacts to: said third coil for conducting energization thereto upon actuation of said first contacts, second contacts actuated by said second armature when said third coil is energized, and circuit means connecting said second contacts to thev other of said pair of coils for conducting energization thereto upon actuation of said second contacts, said resilient means further having such stifiness to permit actuation of said first armature to said other position after energization of said other'coil.

3. Time delay apparatus comprising, a first pair of coils arranged on a first core, each of said first pair of coils being separately and successively energizable and being so wound as to produce, when energized, cumulative excitation of said first core, means for conducting energizetion to one of said first pair of coils, time delay circuit means arranged on said first core and being magnetically coupled with said first pair of coils, a first armature actuatable by said pair of coils, said first armature having one position effected by energization of one of said first pair of coils and having another position efiected by energizationof both of said pair of coils, first resilient means having sufiicient stifiness to permit actuation of said first armature only to said one position after energi'zation of said one coil of said first pair, first contacts actuatable by said first armature in moving to said one position, a second pair of coils arranged on a second core, each of said second. pair of coils being separately and successively energizable and being sowound as to produce, when energized, cumulative excitation of said second core, time delay circuit means arranged on said second core and being magnetically coupled with said second pair of coils, a second armature actuatable by said second pair of coils, said second armature having one position effected by energization of one of said second pair of coils and having another position effected by energization of both said second pair of coils, second resilient means having sufiicient stiffness to permit actuation of said second armature to said: one. position after energi'zation of said one coil of said second pair, circuit means connecting saidfirst contacts to said: one coil of said second pair for conducting energization thereto upon actuation of saidv first contacts, second contacts actuated by said second armature when said one coilv of said second pair is energized, circuit means connecting said. second contacts to the other of said first pair of; coils. for conducting energization thereto. upon; actuation of said second contacts, said first resilient means further having such stiffness: to permit actuation of said first armatureto: its other position. after energizatiorrof said other coil of: said first pair, third contacts actuatable by said. first armature in moving to. its other" position, circuit means connecting said third contacts to the other coil of said second pair for conducting energization thereto upon. actuation of saidv third contacts, said second resilient means further having. such stiffness to permit actuation of said second armature to. said other position. after: energization. of said other coil of saidse condpai'r;

41.. Time delay" apparatus. comprising, a, pair of coils arranged: on. a; core, said. coils being separately and. successively energizable and. being: so

Wound as to produce, when energized, cumulative excitation of said core, means for conducting energization to one of said pair of coils, time delay circuit means including a short circuited winding arranged on said core and being magnetically coupled with said coils, an armature actuatable by said pair of coils, said armature having one position effected by energization of one of said pair of coils and having another position effected by energization of both of said pair of coils, resilient means resisting actuation of said armature, said resilient means having sufficient stiffness to permit actuation of said armature only to said one position after energization of aid one coil, contacts actuatable by said armature in moving to said one position, circuit means made effective by the actuation of said contacts for conducting energization to the other of said pair of coils, said resilient means further having such stiffness to permit actuation of said armature to said other position after energization of said other coil.

5. Time delay apparatus comprising, a pair of coils arranged on a core, said coils being separately and successively energizable and being so wound as to produce, when energized, cumulative excitation of said core, means for conducting energization to one of said pair of coils, time delay circuit means arranged on said core and being magnetically coupled with said coils, an armature actuatable by said pair of coils, said armature having one position effected by energization of one of said pair of coils and having another position efiected by energization of both of said pair of coils, resilient means resisting actuation of said armature, said resilient means having suiiicient stiffness to permit actuation of said armature only to said one position after energization of said one coil, contacts actuatable by said armature in moving to said one position, circuit means made effective by the actuation of said contacts for conducting energization to the other of said pair of coils, said resilient means further having such stiffness to permit actuation of said armature to said other position after energization of said other coil, and resistance means connected in circuit with at least one of said pair of coils for varying the time delay of the apparatus.

6. Time delay apparatus comprising, a first pair of coils arranged on a first core, each of said first pair of coils being separately and successively energizable and being so wound as to produce, when energized, cumulative excitation of said first core, means for conducting energization to one of said first pair of coils, time delay circuit means arranged on said first core and being magnetically coupled with said first pair of coils, a first armature actuatable by said pair of coils, said first armature having one position eiiected by energization of one of said first pair of coils and having another position effected by energization of both of said pairs of coils, first resilient means having sufiicient stiffness to permit actuation of said first armature only to said one position after energization of said one coil of said first pair, first contacts actuatable by said first armature in moving to said one position, a second pair of coils arranged on a second core, each of said second pair of coils bein separately and successively energizable and being so wound as to produce, when energized, cumulative excitation of said second core, time delay circuit means arranged on said second core and being magnetically coupled with said second pair of coils, a second armature actuatable by said second pair of coils, said second armature having one position effected by energization of one of said second pair of coils and having another position effected by energization of both said second pair of coils, second resilient means having sufiicient stiffness to permit actuation of said second armature to said one position after energization of said one coil of said second pair, circuit means connecting said first contacts to said one coil of said second pair for conducting energization thereto upon actuation of said first contacts, second contacts actuated by said second armature when said one coil of said second pair is energized, circuit means connecting said second contacts to the other of said first pair of coils for conducting energization thereto upon actuation of said second contacts, said first resilient means further having such stifiness to permit actuation of said first armature to its other position after energization of said other coil of said first pair, third contacts actuatable by said first armature in moving to its other position, circuit means connecting said third contacts to the other coil of said second pair for conducting energization thereto upon actuation of said third contacts, said second resilient means further having such stiffness to permit actuation of said second armature to said other position after energization of said other coil of said second pair, resistance means connected in circuit with one coil of each of said first and second pairs of coils, and further resistance means in circuit with the other coil of each of said first and. second pairs of coils.

7. Time delay apparatus comprising, a pair of coils interwound on a core, said coils being separately and successively energizable and being so wound as to produce, when energized, cumulative excitation of said core, means for conducting energization to one of said pair of coils, time delay circuit means including a short circuited winding interwound with said pair of coils on said core and bein magnetically coupled with said coils, an armature actuatable by said pair of coils, said armature having one position effected by energization of one of said pair of coils and having another position eiiected by energization of both of said pair of coils, resilient means resisting actuation of said armature, said resilient means having sufiicient stiffness to permit actuation of said armature only to said one position after energization of said one coil, contacts actuatable by said armature in moving to said one position, circuit means made effective by the actuation of said contacts for conducting energization to the other of said pair of coils, said resilient means further having such stiffness to permit actuation of said armature to said other position after energization of said other coil.

8. Time delay apparatus comprising, a pair of coils interwound on a core, said coils being separately and successively energizable and being so wound as to produce, when energized, cumulative excitation of said core, means for conducting energization to one of said pair of coils, time delay circuit means including a conducting mass mounted on said core and being magnetically coupled with said coils, an armature actuatable by said pair of coils, said armature having one position effected by energization of one of said pair of coils and having another position effected by energization of both of said pair of coils, resilient means resisting actuation of said armature, said resilient means having sufficient stifl- 17 ness to permit actuation of said armature only to said one position after energization of said one coil, contacts actuatable by said armature in moving to said one position, circuit means made efiective by the actuation of said contacts for conducting energization to the other of said pair of coils, said resilient means further havin such stiffness to permit actuation of said armature to said other position after energization of said other coil.

JOHN S. BAKE-R.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Ihlder Oct. 20, 1903 Basch Sept. 21, 1915 Reed et a1 Apr. 9, 1918 Hovey Aug. 15, 1933 Schaelchlin Mar. 19, 1935 Clough May 9, 1939 Boeker Nov. 26, 1940 Swenson Feb. 24, 1942 Gauvreau July 13, 1948