US2988608A - Electric time switch with means for automatic opening and delayed reclosure upon power failure - Google Patents

Description

June 13, 1961 ELECTRIC TIME SWITCH WITH MEANS FOR AUTOMATIC OPENING AND DELAY Filed July l0. 1956 J. J. EVERARD ED RECLOSURE UPON POWER FAILURE 2 Sheets-Sheet 1 J0 EPH J .E1/Eene@ AQIM+M AT'TENEYf June 13, 1961 Filed July lO. 1956 J. J. EVERARD ELECTRIC TIME SWITCH AND DELAYED WITH MEANS FOR AUTOMATIC OPENING RECLOSURE UPON POWER FAILURE 2 Sheets-Sheet 2 INVENTOR. Jaaa-PH, J. EVE/enen A frog/v5 V5 United States Patent O ELECTRIC TIME SWITCH WITH MEANS FOR AU- TOMATIC OPENING AND DELAYED RECLO- SURE UPON POWER FAILURE Joseph J. Everard, Manitowoc, Wis., assign'or, by mesne assignments, to American Machine & Foundry Company, New York, N.Y., a corporation of New Jersey Filed July 10, 1956, Ser. No. 597,022 2 Claims. (Cl. 200-35) This invention relates to an electric time switch with means for automatic opening and delayed reclosure upon power failure.

When an electric circuit is complete ata time when line voltage is lost due to any cause, it is sometimes important that the load on the circuit shall not be immediately assumed when the voltage is restored. For instance, if a number of electric motors, each under heavy load, are operating on a circuit when line voltage fails, it is usually desirable that at least some of the motors be taken from the line if voltage is to be restored. This is of special concern if there is no human operator immediately available, as for instance, where time switches are relied upon to control electric apparatus, and the power failure occurs when the time switches have closed a number of the load circuits.

This invention provides means in conjunction with an electrically operated clock mechanism for opening a load circuit 'at a time of power failure or seriously reduced voltage on the line, and also provides means for delayed closing of the load circuit after voltage is reestablished. Furthermore, the invention provides for the above improvements in conjunction with time clock mechanism -for predetermining the delay `and provides for control without necessity for additional switch apparatus in the load circuit.

In the drawings:

FIG. l is a front elevation of a time switch control embodying the invention.

FIG. 2 is a rear elevation of the time switch control of FIG. 1, the parts being shown in position assumed automatically upon failure of line voltage.

FIG. 3 is a section on line 3-3 of FIG. l.

FIG. 4 is a view similar to FIG. 2, but with certain parts removed to show the engagement of time delay mechanism immediately after restoration of voltage on the line and before the elapse of the period of time delay.

FIG. 5 is a view similar to FIG. 4, but showing the parts in the position which they assume upon elapse of the period of time delay; the load control switch being closed but the time delay mechanism being not yet cocked for the next operation.

FIG. 6 is an enlarged detail view of the time delay gears and immediately associated parts in the position which they assume upon declutching and just before restoration to their position of dwell to await the next power failure.

FIG. 7 is a section on line 7-7 of FIG. 6.

The time control unit into which the improvements of the present invention are tted as disclosed in the above identified drawings is the Time Switch described in U.S.

Patent No. 2,596,330 to I. l. Everard dated May 13, 1952.

The mechanism of this time switch includes La front or frame plate 1d, flanged for stiffness at l1- 12,

A large 24-hour dial 13 on a tubular shaft 14 has dial tabs 15 adjustably slidable alternatively to strike or not to strike ya cam follower 16 on a cam arm 17 mounted for operator.

ICC

At the rear of the plate 10, the rock shaft 18 is equipped with a switch operating arm 20. The purpose of this switch operating arm, so mounted to the rock shaft as to move concomitantly with the cam 16, is to press or relieve pressure upon plunger 21 of micro-switch 22. In the particular apparatus shown in the drawings, switch 22 is normally closed. There is a synchronous motor 23 with reduction gearing in a case at 24 to drive a shaft 2S connected by a chain of gears and pinions respectively at 26, 27, 28, 29 and 30 for the drive of a large pinion at 31 meshed with a dial gear 32 for rotation of the 24-hour dial. It will be noted that the large gear 32 is mounted to the tubular shaft of the 24-hour dial by the friction plates 33 and 34 to provide for manual rotative placement of the 24-hour dial without rotating gear 32 or imposing unnecessary strains upon the train of gears 25-30.

Referring again to the disclosure in Patent No. 2,596,- 330, summarized in the short description of the parts thus far described in the paragraphs above, so long as the synchronous motor 23 is operating as fa timer drive motor, the chain of pinions and gears 25-32 rotates the 24-hour dial 13 Iand at such timed intervals as may be dictated by the particular tabs 15 which have been positioned for switch actuation, on and off, the cam follower 16 will rock the rock shaft and its arms 17 and 20 whereby to press plunger 21 or release it for switch control of the electric load to be controlled by the time switch. Since the synchronous motor 23 is energized at the same time that a circuit through the switch 22 is energized, it is obvious that when there is a voltage failure in the supply line to the switch 22 and to the synchronous motor 23, there is nothing in the apparatus thus far disclosed to open the load circuit under control of the switch 22 if it so happens that the failure occurs when the switch 22 is closed. Therefore, the full load of the circuit controlled by switch 22 is on the line when lan attempt is made to restore voltage after such failure. The instant invention provides means for automatic opening of the switch 22 and a delayed closure with predetermined period of delay as will be clear from the following description.

The broad principle upon which this invention operates is the provision of means for delaying the closing of a load circuit after a power failure or `loss of voltage and where a time control switch in control of such load circuit is made to include apparatus lto control the means for delay interjected for a short time so that the same clock operation for general ytime control purposes also times the delay.

Upon the rearward side of the frame plate `1l) is a solenoid assembly 40 including a coil 41 which is energized whenever current is available for energization of the load controlled by switch 22. There are guide means at 42 in the form of a yoke secured .to a magnetically responsive armature 43, and this yoke is connected to a time delay link 44 extending upwardly to a spring suspension element 45. This spring suspension element is connected to a bracket 46 extending outwardly a short distance from and thus positioning the time delay link parallel to the frame plate 10.

vNear the lower end of the time delay link 44, there is a slot 47 through which one end of a switch release lever 48 is extended. This switch release lever is pivot-ally mounted upon a fixed stub 49 and the other end of this lever is positioned to rest against a pin 50 extending laterally from switch operating arm 20. The slot 47 is somewhat longer in a vertical dimension than is the end of the switch release lever which extends therethrough, but there is a tension spring 511 extending between this end of the lever 48 land an outstanding bracket 52 forming part of link 44, thus tending to hold the lever 48 at the lower end of the slot 47.

It is now apparent from this description that when the aeesos solenoid 46 is energized, armature 43 is pulled down into the position shown in FIGS. 4 and 5 and the switch release arm is not impeded in its movement. The arm will assume the position shown -in FIG. 5 and the spring 46 is extended. In this position of the switch release lever, the pin Sil is not pushed downwardly by the right hand end of the lever 48. This permits the switch operating arm to move upwardly in response to the natural bias of the switch plunger 21 1and the switch is closed. However, if insufficient current energizes solenoid coil 4l and spring 46 pulls the link 44 upwardly las shown in FIG. 2, the end of the switch release arm 48 extending through the link 44 is positively moved to the position Shown in FIG. 2 lin which the switch release arm bears firmly against pin 50 and the switch operating arm is forced to bear against plunger 2 whereby to open the switch. It will be understood that the tension spring 46 is suiiicient to overcome the natural bias of the switch 22 to closed position.

Near the upper end of the time delay link 44, there is another slot 55 (see FIG. 6), through which is extended the link operating end of clutch lever 56. This clutch lever is pivotally mounted on a bearing sleeve 57 carried by the same tubular mounting shaft 58 which also car-ries tubular shaft I4.` The bearing sleeve is long enough to serve not only the clutch `lever but also clutch Sub-lever 59 freely oscillatable as described below. Nut 60 threaded upon the tubular shaft 58 (see FIG. 3) bears against the end of sleeve 57 and prevents the levers from moving away from each other and from the plate y10.

Concentric with tubular shaft 58 is a clutch release shaft 6l at the rear end of which is clutch release hub 62 and on the front end of which is time delay pointer 63. Both the hub 62 and the hub of pointer 63 are secured to shaft 6l by set screws `as shown clearly in FIG. 3. A time delay dial at 65 is mounted to a hub 66 iixed upon tubular shaft 5S by a set screw, and upon this hub mounted for frictional rotation respecting the hub and between a collar 67 and nut 68, `is an adjustable pointer 69 which determines the degrees of oscillation of shaft 61 which may be freely made by the pointer between a fixed pin '70 secured to the time delay dial and the time delay pointer under the urge of a torsion spring 71. This spring is wrapped around hub 62 and is secured as to one end of the torsion spring on a bracket 72 forming part of the frame and the other end is secured to clutch release pin 73. It will be noted that clutch release pin 73 is secured to the side of clutch release gear 74 forming part of hub 62. This gear 74 is actuated by pinion 75 carried by stub shaft 'F6 fixed to clutch sub-lever 59. Pinion 75 is secured to gear 77 mounted upon the same stub shaft 76 so as to turn with the pinion.

While clutch lever 56 is moveable in limited oscillation under control of link A44, the clutch sub-lever 59, shown in shaded surface in FIG. 6, can oscillate between post Si) at its lowermost limit and an upper position in which gear 77 is in full mesh with pinion S1 secured to and rotatable with gear 26. Thus if the clutch sub-lever is in its upper position, due to the pull of armature 43, gear 77 will be rotated by gear 81.

A portion of clutch lever 56 extends downwardly at 82 and is shaped to provide a release stop rearwardly disposed at 83. This provides an abutment for clutch release lever 85 mounted for oscillation on stub shaft 76. The clutch release lever is shaped to provide a stop step 86, a spring bias arm 87 and a release nose S8. A tension spring S9 between the bias arm and post 80 urges the stop step against release stop S3, thus keeping the nose as far as possible to the left as seen in FIGS. 4, 5, and 6, but the riser 90 of the step limits the oscillation in that direction.

It is nonI apparent that when armature 43 pulls link 44 downward at a time when stop step 86 is supported by release stop 83, the clutch lever 56 and the clutch sublever 59 operate as a unit to bring the gear 77 into mesh with gear Si, but ifl clutch release lever 85 is pivotcd counterclockwise, as for instance, by pressure against nose 88, the step 86 will be moved away from stop 83 and the sub-lever will be pulled down against post 80, thereby disengaging gear 77 from gear 81.

Mounted on a stub shaft which extends rearwardly from the plate 10, there is a switch lock lever 96 shaped to include a nose pad 97 at its upper end and shaped at its lower end to include a lock step 98. The nose pad is swingable in an arc to bring it against nose 63 and extends upwardly beside clutch release gear 74 so as to be in the path of movement of clutch release pin 73. There is a torsion spring 99 wrapped around stub shaft 95 and so connected to switch lock lever 96 and to release stop 83 that the switch lock lever is biased for counterclockwise oscillation. This movement is restrained, however, by a switch lock pad lili() forming a part of switch release arm 48 so disposed that if the switch release arm is oscillated in a clockwise direction to the position shown in FIG. 4, the step 98 of the switch lock lever will move over the pad 166 and lock the switch in open position where it must remain until something occurs to provide a clockwise movement ofthe switch lock lever 96.

Operation Assuming that the dial 13 is in the position shown in FIG. l so that some of the tabs l5 are set to permit the lever 17 to assume its upward position and assuming that time delay pointer 63 is set against adjusting pointer 69 for a 60-second delay as shown in FIG. l, a power failure then occurring would tnd the switch in the position shown in FIG. 5 and with the clutch release lever 85 in the position shown in FIG. 6. Clutch release pin '73 would, by reason of the position of time delay pointer 63 be `positioned as shown in FIG. 2 so that the operation of time clock 23 when clutched to drive gear 74 will require 60 seconds of clock operation to bring clutch release pin 73 to the position shown in FIG. 6. Immediately upon power failure, armature 43 released by solenoid 4i) is pulled to its uppermost position by tension spring 45. Switch release lever 48, which has theretofore been in a position shown in FIG. 5, is forced immediately to the position shown in FIG. 2 so that switch lock lever 96 can respond to the bias of spring 99 and pass the lock step 9S over pad 100. This locks switch release lever 48 in position to hold the switch open against the normal bias of the switch 22 to closed position.

During continued power failure, the parts remain in this position. The clock 24 is stopped.

When current is restored, the clock 24 resumes operation for its function as a time switch and solenoid 40 is re-energized so as to pull the armature 43 to a position shown in FIG. 4. Even though the armature has been pulled downwardly and the link 44 is no longer forcing the switch release lever to the position shown in FIG. 4, it is impossible for the switch release lever to immediately escape lock step 98; therefore, the switch 22 is held in open position. i

When the link 44 was pulled downwardly upon restora tion of voltage in coil 4l, the left end of lever 56 was pulled downwardly and the right end thereof including release stop 83 was thmst upwardly. Clutch release lever 85, therefore, forced the clutch sub-lever upwardly sufliciently to mesh gear 77 with gear 81. These gears are, therefore, in rotation as driven by the clock motor 24 whereby to drive gear 74 and pin 73 in the direction indicated by the arrow (see FIG. 4). The gear ratio in the gears and pinions is such that in 60 seconds pin 73 will have moved into contact with pad 97 and will have pushed the pad suiiiciently to release stop step 98 from pad 100. Almost immediately thereafter, the pin 73 will have moved nose pad 97 against nose 88 of clutch release lever S5 and step 86 of clutch release lever 85 will be moved off of release stop 83 thus permitting the sul lever 59Y to drop by gravity. and with the assistance of tersion spring S9 for disengagement of gear 77 from gear Sl.

The parts then assume the position shown in FIG. 6 and since the disengagement of the gear releases the parts for response to the tension spring 71, the gears supported by levers 56 and S9 return to the position shown in FIG. 4.

Clutch release lever 85 remains in the position shown in FIG. 6 until another power failure or loss of voltage in the coil 41 returns the lever 56 to the position shown in FIG. 2 at which time the stop 83 is re-engaged with step 86 to recock the clutch release lever in readiness for a gear meshing operation upon restoration of power as above described.

It will be noted, of course, that a spring at 105 provides for strain release in the event that restoration of power and a downward pull upon link 44 brings the gears together at; 79-81 when the teeth of the gears are in a position to clash.

During the period in which the devices controlled by switch 22 are in normal operation, switch lock lever 96 is in a position shown in FIG. 5 with the lever bearing against the pad 100 under the bias of spring 99.

I claim:

1. In an automatic delayed switch control apparatus for a device having a circuit and an electrically responsive link adapted to move to an extreme position when the circuit is energized, an electric gear equipped motor connected for energization when said circuit is energized, a clutch lever having a gear and gear operated release pin, said clutch lever being rockably mounted and connected to the link whereby to be biased to a position for mesh of said gears when the link is in said extreme position and biased to separate the gears when the link is away from said extreme position, a clutch release latch positioned to releasably hold the clutch lever in gear cngaged position, a controlled switch having normally closed contacts and an actuator for the opening thereof, said actuator being positioned for application thereagainst of a biasing member, a biasing member to operate the actuator when the link moves away from said extreme position, a switch latch to hold the switch actuator in switch open position, and a switch lock lever biased to hold the switch latch in switch open position, said switch lock lever and said clutch lever latch being positioned for movement by the release pin whereby the clutch lever will move to unmesh said gears and the controlled switch will move to closed position upon predetermined rotation of said gears.

2. The apparatus of claim l wherein the clutch lever gear is mounted to the clutch lever for biased return to a released position when out of mesh with the motor gear.

References Cited in the tile of this patent UNITED STATES PATENTS 2,163,419 Warren June 20, 1939 2,596,330 Everard May 13, 1952 2,713,622 Smith July 19, 1955 2,744,573 Judson et al. May 8, 1956 2,747,142 Kradel et al. May 22, 1956

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