US2195457A - Time system - Google Patents

Description

April 1940- E. 'B.-JACK$ON 2,195,457

TIME SYSTEM Filed Oct. 24, 1936 1 V5 NTOR Edward B.Jack$on Attorney Patented Apr. 2, 1940 UNITED STATES TIME SYSTEM Edward B. Jackson, Downers Grove, 111., ,assignor, by mesne assignments, to General Time Instruments Corporation, New York, N. Y., a corporation of Delaware Application October 24, 1936, Serial No. 107,389

8 Claims. The present invention relates in general to time systems and more particularly to a cor-' rective time system in which each secondary apparatus is controlled and periodically corrected or synchronized by a primary or master apparatus. The main object of the invention is the provision of a simplified system of this type for use where alternating current is employed as the source of power.

The present invention may be considered a improvement over the system disclosed in my co-pending application Serial No. 7,064, filed February 18, 1935 now Patent No. 2,086,715 granted July 13, 1937. The primary or master apparatus disclosed herein is the same as disclosed in said co-pending application'and the novel features of this master apparatus are claimed in said application. 7

According to a feature of the presentinventi'on the secondary apparatus which is controlled by the half-wave and full-wave rectified alternating current impulses transmitted from the master apparatus has been greatly simplified and requires only a single winding on" the operating magnet.

According to another feature of the invention, a resistance or a one-way valve'is connected in shunt of the secondary magnet winding in series with a contact controlled in accordance with the chronological condition of the secondary apparatus. The presence or absence of this device in the circuit and the kind of impulses being received from the master apparatus determine whether or not the secondary apparatus is to beadvanced by such impulses. According to a further feature of the invention, the operation of an electromagnet by rectified alternating current is greatly improved by bridging an asymmetric cell or so-called oneway electric valve across the terminals of the magnet winding.

Another feature of the inventionlies in the elimination of sparking or arcing at the contacts of an electric circuit which control the flow of current to an inductively wound electrical device. This is accomplished to a much greater degree than heretofore possible by connecting a one-way valve in shunt of the inductive winding.

The above and other objects and features of my invention will best be understood from a perusal of the following specification when read in connection with the accompanying drawing comprising Figures 1 to 3, inclusive, in which: Figure '1 is a schematic circuit diagram of a corrective time system embodying the present invention,

Figure 2 is a schematic circuit diagram showing a modification of the secondary apparatuses, and

Figure 3 is a schematic circuit diagram illustrating the use of a one-way electric valve to eliminate sparking or arcing at the circuit controlling contacts.

Referring to the drawing in general, Fig. 1 discloses a two-wire corrective circuit in which M diagrammatically represents the master clock having a frame indicated at l, the usual minute appear in the detailed description of the operation of the system. Cams 3 and 4 are hour cams mounted on the minute handshaft 2 and cam H is a. minute cam mounted on the second shaft ill of the master clock. The fast contacts M are controlled by the verge 13 of the .clock in well-known manner.

, SI and S2 diagrammatically represent the secondary apparatuses, each comprising an operating magnet (23, 43) adapted to drive the secondary time mechanism by means of the usual ratchet and pawl construction including an armature (26, 45) for the magnet, an armature stop (28, 41), an operating spring (21, 46), 'a pawl (29, 49) mounted on the armature, and a ratchet wheel (30, 48) engaged by thev pawl. The ratchet wheel is 'mounted on the minute shaft (3|, 50) of the secondaryapparatus as is also the cam (32, 5|) which controls the contacts (33, 52), connecting or disconnecting the resistance (34, 44) from in shunt of the magnet winding.

Figure 2 of the drawing discloses a modification of the secondary apparatus circuit in which a one-way electric valve (62, 12) is substituted in, the shunt circuit for the resistance of Figure 1.

Figure 3 discloses a spark reducing or eliminating circuit in which an inductively wound magnet or other device 15 is connected in series with a battery 11 and the circuit 18. A one-way electric valve 16 is connected in shunt of the inductive winding.

Having briefly described the apparatus shown on the drawing, a detailed explanation of the operation of the several circuits will now be given.

Referring first to Fig. 1, contacts I2 are closed momentarily once each minute by cam l I, thereby transmitting an operating impulse to the secondary apparatuses over the following circuit: from line i! of the A. C. supply source, contacts conductor l8, section 40 of the rectifier R, conductor 2%, through conductors and 54, magnets L3 and 3 and conductors 35 and 53 in multiple, conductor 2!, contacts 3 and 6, to the other side of the supply source over conductor l6.

Referring to the secondary apparatuses Si and S2 it will be seen that the secondary apparatus Si is fast and has reached its 59th minute position, in which position the cam 32 operates contacts 33 to open the shunt circuit through resistance 34. Secondary apparatus S2 is on time or slow since it has not yet reached its 59th minute position.

The magnets 23 and 43 are so wound that they will not operate on receipt of half-wave rectified alternating current impulses with the shunt circuit through the associated resistances open. However, when the resistance is connected in multiple with the magnet winding, the magnet will respond to such impulses. The probable explanation for this operation is that with the shunt circuit open, the magnetism built up in the core of the magnet by one half-wave of current will die away during the following interval of no current before the succeeding half-wave occurs to continue the building up of the magnetic field. Thus during a half-wave rectified A. C. impulse the magnetic field does not build up to the point where the magnet will operate.

With the resistance connected in shunt of the magnet winding, a closed path is provided for the current which is induced in the inductive winding due to the dying down of the magnetic field during the intervals between successive halfwaves of current Ihis induced current fiows in such a direction as to tend to maintain the magnetic field and as a result the field has died down very little before the neXt half-Wave occurs to continue to increase the magnetism. As a result the magnetic field will be built up to a point where the magnet will operate.

The shunt circuits of the secondary magnets are normally closed and the system operates on half-wave rectified alternating current impulses transmitted over the circuit previously traced. Magnet 33 will operate in this circuit and advance the secondary apparatus S2 one step. Apparatus S5, however, is assumed to be fast and cam 32 has already opened contacts 33 as previously explained. Magnet 23 therefore cannot operate and S! remains in its 59th minute position.

The normal operation described above continues until shortly after the master clock has trans mitted the 59th impulse. At about 59 minutes 10 seconds after the hour, cam 4 allows contacts 8 to close thereby connecting the fast contacts 14 in the impulsing circuit. These contacts send out a momentary impulse about every two seconds and all secondary apparatuses, such as S2 which is assumed to be slow, are rapidly advanced until each reaches its 59th minute position, in which position the contacts such as 52 open the shunt circuit through resistance 54 and render the associated magnet 43 unresponsive to the half-wave rectified A. C. impulses.

At about 59 minutes 40 seconds after the hour,

cam 4 again opens contacts 9 thereby removing the fast contacts l4 from the circuit and stopping the transmission of the rapid accelerating impulses. All of the secondary apparatuses have now been operated to position 59 and have been stopped in that position.

Shortly before the master clock reaches position 60 or the hour position, at about 59 minutes 59 seconds after the hour, cam 3 opens contacts 6 and 8 and closes contacts 5 and I. When minute contacts l2 are then closed in position 60 of the master clock, the circuit for the secondary operating magnets extends from one side of the power source over the conductor ll, contacts [2, conductor 18, section 40 of rectifier R, conductor 20, conductor 33 of secondary apparatus SI, winding of magnet 23, conductor 35, conductor 2|, contacts 1, conductor 22, section 42 of rectifier R, conductor l9, contacts 5, and over conductor 16 to the other side of the power source. Alternate half-waves Will of course pass through sections 4! and 43 of rectifier R instead of sections 49 and 42. Parallel circuits extend from lines 20 and 21 through each of the other secondary apparatuses connected to the circuit.

The above impulsing circuit now includes the full-wave bridge rectifier and the secondary magnets will all respond to the impulse of the fullwave rectified alternating current to advance the secondary apparatuses into position 60 and into synchronism with the master clock. In position (it, the cam in each secondary, such as cam 32 of SI, again permits the contacts such as 33 to close, thereby again closing the shunt circuit through the associated resistance. All the secondary apparatuses are now again in condition to be operated by half wave rectified alternating current impulses. Several full-wave rectified current impulses may be sent out by the master clock before cam 3 again opens contacts 5 and l and closes contacts 6 and 8 to disconnect the full-wave bridge rectifier and reconnect the halfwave rectifier unit 40 in the circuit. This will insure that all of the secondary apparatuses have been advanced from position 59 and are again in condition to be advanced by half-wave rectified alternating current impulses. Therefore, the switch-over from full-wave to half-wave operation may preferably occur several minutes after the hour.

The secondary apparatuses S3 and S4, shown in Fig. 2 of the drawing, operate with the master clock shown in Fig. l. The principle of operation is the same as in the system of Fig. 1. However,

a one-way electric valve has been provided in each secondary apparatus to take the place of the resistance used in the embodiment shown in Fig. 1.

The one-way valve must of course be properly connected across the secondary magnet winding so that it will block the rectified current pulsations. Thus during normal operation on halfwave rectified alternating current impulses with the valve connected in the circuit as shown for 65 is in such a. direction as to keep up the mag- 7 netlc field. This induced current therefore has a low resistance path through valve 12 and contacts II.

From the foregoing it will be realized that the one-way valve has characteristics which make it much more efiicient for the purpose than the resistance used in Fig. l. The valve offers practically an absolute block'for the current pulsations, thereby forcing all of the current through the magnet winding, and is practically a short circuit of the winding during the intervals between pulsations, thereby presenting very little opposition to the flow of the induced current. With the resistance of Fig. 1 some of the current of each pulsation flows through the resistance in multiple with the magnet winding and is therefore ineffective on the magnetic field of the magnet. Also during the intervals between pulsations, the induced current is lower due to the high resistance of the shunt.

The operation of the system of Fig. 2 being the same as that of Fig. 1, it is not thought necessary to repeat the explanation of a complete cycle of operation. The circuits of secondary apparatuses S3 and S4 correspond in all respects to those of SI and S2 except that the one-way valves 62 and 12 are substituted for resistances 34 and 44. As pointed out above, the function of the valve is the same as that of the resistance but its operation is much more eflicient as its characteristics make it ideal for the purpose.

Figure 3 of the drawing discloses a schematic circuit diagram of the use of a one-way valve to reduce or eliminate arcing at the contacts controlling current through an inductive device. Since it is this arcing at the contacts which rapidly deteriorates the metal, pits the surfaces and causes contact trouble, it is highly important that arcing be reduced to a minimum or eliminated entirely in electric circuits. This is especially true where the contacts are frequent 1y operated as in electric time systems.

The circuit of Fig. 3 includes an inductively wound device such as a magnet 15, a source of current 11, and the circuit making and breaking contacts 18. In order to eliminate the spark which would occur at contacts 18, when opened, due to the induced voltage in the Winding of magnet 15, a one-way valve is bridged across the terminals of the magnet winding. This valve is connected so that it blocks the fiow of current when contacts 18 are closed, forcing all of the current through the magnet winding. When contacts 18 are opened a voltage is induced in the windings of magnet 15 due to the collapse of the magnetic field. As is well known, this voltage produces a current in a direction so as to oppose the change in the magnetic field. The one-way valve is practically a short circuit for current in this direction and the induced current therefore has a low resistance path through the valve and dissipates itself in the magnet winding. There is no tendency for the current to seek the high resistance path through the separating contacts 18 and accordingly the sparking or arcing at these contacts is eliminated.

From the foregoing it will be seen that the use of a one-way valve in shunt of the inductive winding provides the ideal conditions for the elimination of contact arcing. With the contacts closed it ofiers practically an open circuit to the fiow of any current through the shunt. As soon as the contacts are opened and the magnetic field begins to die down, thevalve oflers practically a zero resistance path for the current induced in the magnet winding.

Having described the claimed as new and is desired to have protected by Letters Patent is:

1. In a time-controlled system, master apparatus and secondary apparatus connected by a control circuit, means in said master apparatus for transmitting half-wave and full-wave rectified alternating current impulses over said circuit, an operating magnet in said secondary apparatus having a winding connected to said circuit, and means for determining the efiectiveness of said half-wave rectified current impulses to operate said magnet, said means including a non-inductive resistance and contacts. for connecting said resistance in multiple with said winding con trolled in accordance with secondary apparatus time.

2. In a time-controlled system, master apparatus and secondary apparatus connected by a control circuit, means in said master apparatus for transmitting half-wave and full-wave rectified alternating current impulses over said circuit, an operating magnet for said secondary apparatus having a single winding permanently connected. to said control circuit, a normally closed shunt circuit for said magnet including a resistance device, and means controlled in accordance with the chronological condition of said secondary apparatus for opening said shunt circuit to render said magnet unresponsive. to half-wave rectified current impulses received over said circuit.

3. In a time-controlled system, master apparatus and secondary apparatus connected by a control circuit, means in said master apparatus for transmitting half-wave and full-wave rectified current impulses over said circuit in, accordance with a predetermined schedule, an impulse magnet for said secondary apparatus: connected to said circuit, a shunt circuit for said magnet including a non-inductive resistance, and means for determining the effectiveness of said impulses to operate said magnet including contacts for selectively opening and closing said shunt circuit in accordance with secondary apparatus time.

4. In. a corrective time-controlled system, master apparatus and secondary apparatus connected by a control circuit, means in said master apparatus for transmitting normal operating and rapid accelerating impulses of half-wave rectified current over said circuit, an operating magnet for said secondary apparatus connected to said circuit, a normally closed. shunt circuit for said magnet including a non-inductive resistance, means effective in a predetermined position of said secondary apparatus for opening said shunt circuit to render said magnet unresponsive to said half-wave rectified current impulses, and means in said master apparatus for transmitting at least one impulse of full-wave rectified current to again render said magnet responsive to half-wave rectified current impulses.

5. In a corrective time-controlledsystem, master apparatus and secondary apparatus connected by a control circuit, means in said master apparatus for transmitting half-Wave rectified current operating and accelerating impulses over said circuit, an operating magnet for said secondary apparatus connected to said circuit, a non-inductive resistance normally connected in multiple with said magnet, means for disconnecting said resistance when said secondary apinvention, what is paratus reaches a predetermined position to render said magnet unresponsive to further halfwave rectified current impulses, and means in said master apparatus for transmitting an impulse of full-wave rectified current to again operate said magnet.

6. In a secondary apparatus for use in a corrective time system, an incoming control circuit over which operating impulses are received, an operating magnet connected to said circuit, a one-way electric valve, and contacts controlled in accordance with secondary apparatus time for connecting said valve in multiple with said magnet.

7. In a time controlled system, master apparatus and secondary apparatus connected by a control circuit, means in said master apparatus for transmitting half-wave and full-Wave rectified alternating current impulses over said circuit, an operating magnet for said secondary apparatus connected to said control circuit, a normally transmitting half-wave and full-wave rectified current impulses over said circuit in accordance with a pre-determined schedule, an impulse magnet for said secondary apparatus connected to said circuit, a shunt circuit for said magnet including polarity trap means, and means for determining the effectiveness of said impulses to operate said magnet including contacts for selectively opening and closing said shunt circuit in accordance with secondary apparatus time.

EDWARD B. JACKSON.

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