US2675442A

US2675442A - Van ryan

Info

Publication number: US2675442A
Authority: US
Publication date: 1954-04-13
Anticipated expiration: 1971-04-13

Description

April 13, 1954 A. VAN RYAN 2,675,442

REMOTE CONTROLLED SWITCH Filed March 3,- 1951 2 Sheets-Sheet 1 SYA/Cl/AONO as 5.62 F START/N6 INVENTOR.

April 13, 1954 A. VAN RYAN 2,675,442

REMOTE CONTROLLED SWITCH Filed March 3, 1951 2 Sheets-Sheet 2 '7; zylszvr%.

l1 0 a By 0177 n y I? J liarn e Patented Apr. 13, 1954 UNITED STATES ATENT OFFICE 2,675,442 REMOTE CONTROLLED SWITCH Application March 3, 1951', Serial No. 213,793

2 Claims.

This-"mvention' relates to a remote controlled switch for use in a system whichprovides for the remote control by carrier current of a predetermined frequency superimposed on power lines andcontrolling the energization of any desired type of apparatus operated by electric power. "Objects of this'invention are to provide a receiving apparatus 'whichpermits the remote control of a single or a plurality of such devices when a carrier current of a selected frequency is superimposed on-the power line and is maintained for certainselected time'int'ervals. This invention is an improvement over that disclosed in the copending-"application 'of- William G. Coe, Serial No. 125,589, filed November 4, 1949, for Control System and Receiver *Therefor, assigned to the same assign'ee as the present application.

A further -objectof this invention is to provide a series of receivers which are so constructed and connected in the system that all of the receivers are put into the same position when a predetermined signal is sent' out from the control station.

' A further primary'object' is to provide a, receivenwhich is controlled by carrier current of a predetermined frequency and which has a selfstarting synchronous motor operated through suitable mechanism including a magnetic clutch for driving a cam or similar member through the clutch and with the clutch arranged to normallyremain open and to be closed magnetically when power is supplied the motor and to so associatethis motor and clutch mechanism with the cam follower that the "cam follower will p duce a bias on the cam and return the cam to anyone of aplurality of initial positions depending on the last signal received, such cam follower serving to rotate the cam without rotating the motor.

-A further object is to provide a receiver which is not disturbed by lightning surges or other transient impulses but which responds to the carrier current when the carrier current is maintained for a predetermined selected interval of time.

'In greater detail, further objects are to provide a receiving apparatus for a remote control system; as set forth hereinabove, in which a selfstarting synchronous motor drives a cam and a normally open magnetically closed clutch through suitable reduction mechanism, in which the cam is provided with a series of teeth provided with slanting surfaces of different lengths arranged in an alternate manner so that long and hort"spaces follow eachother in a regular sequence, the surface of the teeth being such that a spring pressed cam follower acting upon the teeth will cause a reverse rotation of the cam in the event that a spurious signal or a signal of shorter duration than that required for the operation of the cam through one tooth length is received, so that the cam will return to its initial or zero position when the spurious signal ceases, to thereby always start the cam from its zero or initial position for each given tooth.

An embodiment of the invention is shown in the accompanying drawings, in which:

Figure 1 is a schematic View of the apparatus showing it connected to a power line.

Figure 2 is a view of the cam and associated parts showing th receiver in the on position.

Figure 3 is a corresponding View showing the receiver in the off position.

Figure 4 shows the position of the parts when a'spurious signal has been received.

Figure 5 shows the position of the parts when the cam moves back to one of its zero positions after cessation of the spurious signal.

Referring to the drawings, particularly to Figure 1, it will be seen that the power lines are indicated by the reference character I and that a filter for the predetermined selected frequency is indicated generally by the reference character 2 and may consist of an inductance 3 and a condenser i. A bridge type rectifier indicated by the reference character 5 is connected on opposite sides of the inductance 3 or the condenser the first arrangement having been shown in Figure 1, and a protective resistor 5 is interposed in this circuit. The rectified current is passed to the energizing coil 7 of a sensitive relay 8 whose armature 9 controls the opening and closing of the circuit of the self-starting synchronous motor 10. This self-starting, synchronous motor is provided with reduction gearing and a normally open magnetic clutch which closes when the motor is energized. The motor drives a'drive shaft H which is rigidly secured to a notched cam 12. The drive shaft II has loosely mounted thereon a toothed wheel 13 which is driven from the toothed cam l2 by means of a pin it carried by the cam l2, so that the cam may have a limited motion with respect to the toothed wheel it, the toothed wheel serving to hold the contact means open under predetermined conditions as will appear hereinafter.

In Figure 1 the load is'indicated by the reference character It and is connected between the mains -l and through the contact mechanism indicated generally by the reference character It in Figure 1. This contact mechanism, as may be seen more clearly from Figures 2 through 5, consists of a movable arm I! which is provided with a movable contact it, such contact coacting with the stationary contact iii carried by the terminal member 21. The movable arm I7 is carried by the other terminal member 2 I.

A cam follower indicated by the reference charactor 22 is provided and coacts with the cam I2. The cam follower may consist of a roller carried by a spring arm 23.

The cam I2 is provided with a series of notches indicated by the

reference characters

24 and 25. Each of the notches is provided with a slanting inner face indicated respectively by the

reference characters

26 and 21. The slanting face 26 is shorter than the slanting face 21 and for the construction chosen for illustration, the slanting face 25 may include 30 of the cam and the slanting face 21 may include 42 of the cam, thus giving a total of 72. Five pairs of notches are provided for the cam. Obviously, if a synchronous motor has gearing of the proper proportions, the cam I2 may be rotated once every minute if the motor is continuously energized. 1

and if it is rotated for a period of seven seconds,

the complete travel over the face 2'! is obtained. With an arrangement such as described hereinabove, the carrier current of the selected frequency is maintained for either of two selected periods, namely for a period of six seconds obtaining the closing or the on position of the contact means, and for a period of eight seconds for securing the opening or off position of the contact means. The above construction may be stated in other words, namely that the cam is provided with a series of pairs of teeth, the teeth of each pair being of different lengths so that a short length tooth follows a long length tooth in a regular sequence as the cam rotates.

It is to be noted that the inner end of each of the

notches

25 and 26 is provided with a rounded portion 28 which corresponds to the curvature of the cam follower or roller 22 so that the roller will seat in the corresponding end portion 28 of the selected notch. These end portions correspond to the zero position or initial position for either the on or off signal as will appear hereinafter.

The operation of the apparatus is as follows:

Assuming that a signal of the predetermined frequency is superimposed on the power lines I, it is apparent that the sensitive relay 8 will be energized and the motor started. If the parts are in the position shown in Figure 2 and the signal persists for eight seconds, the motor will rotate the cam I2 slightly past the position shown in Figure 3 and the parts will return to such position with the contact means I6 open. If it is desired to close the switch means, a signal of six seconds duration is transmitted over the power lines and the motor rotates the cam slightly past the position shown in Figure 2 and the parts will return to such position with the contacts closed.

It is to be noted that when the switch or contact means is moved to the open position or off position as shown in Figure 3, that the toothed wheel I3, or second cam, is moved so that one of the teeth 29 will be positioned beneath the movable contact arm I T and will hold the switch in open or oil position. Assume now that a spurious signal or a signal of a duration less than that required to move the parts to the next position or on position is transmitted by some undesirable disturbance. It is apparent that the motor will rotate the cam I2 only part-way towards the next notch, for example as shown in Figure 4. The tooth 29 which is positioned below the movable contact arm- I! is not moved past such arm but is moved to the position shown in Figure 4. When the spurious signal ceases, it will be found that there is a force acting on the cam I2 tending to rotate it in the reverse direction as shown in Figure 4 back to the zero position as shown in Figure 5 with, however, the contacts remaining in open position. Obvious ly, the same thing would occur if the switch had been closed and a spurious signal of a shorter duration than that required to operate the switch had been received. The reason for this is that the

slanting faces

26 and 27 are so arranged that a reverse torque or bias is imparted to the cam I2. From an examination of Figures 2 through 5 it is clear that the

faces

26 and 21 have their minimum radial distance adjacent the zero or initial positions, that is to say, adjacent the seating portions or seats 28 and will have their maximum radial positions adjacent the tips of the teeth.

It is to be noted that the portions 28 of the notches constitute seating portions for the cam follower 22 and that when the cam or notched wheel I2 is in such a position that the cam follower 22 is seated within one of the portions 28. such cam I2 is then in its zero or initial position for either the on or off motion of the cam wheel. This insures correct timing, for the cam wheel I2 always starts from zero or initial position when any signal is received.

It is clear from the above discussion that no matter what spurious signal may be received, it will necessarily be of a shorter duration than that required to operate the switch and that the parts will return to their zero position after the disturbance ceases so that the correct timing for the next received signal will always be obtained. In other words, the cam will always start from its zero position for either on" or oil? operation of the switch.

It has been found that friction can be meterially reduced by the use of the freely mounted toothed wheel or second cam I3. Normally, the toothed wheel or second cam I3 is driven from the first cam I2 by means of the pin I4 which provides limited motion of the cam I2 with reference to the toothed wheel or holding wheel I3. For instance, when the reverse rotation of the cam I2 with reference to the holding wheel or toothed wheel I3 occurs, as in Figure 4, the pin I4 will move to an intermediate position, for example as shown in Figure 5, leaving the appropriate projection or tooth 29 of the holding wheel I3 positioned beneath the movable contact arm I], thus holding such arm in the off" position.

It is to be understood that the specific times and angles hereinabove given are not to be construed as limiting. However, it has been found that 30 and 42 degrees between successive teeth for a l R. P. M. cam is a convenient construchowever, for six and eight seconds, respectively, and secures a slight over-travel of the cam. This, however, is taken care of by the reverse rotation imparted to the cam by the inwardly biased follower as discussed hereinabove.

It will be seen that a very simple and reliable type of receiver has been provided which is not disturbed by lightning or other surges or by any signal or disturbance of lesser duration than that required for either the opening or closing operation.

If a series of these receivers are employed, they are all energized for the same signal and will necessarily keep in step with each other. However, if through any means whatsoever, one or more of the receivers are out of step with the remaining group, they are all placed in the same position when the signal of the shortest duration, namely six seconds as hereinabove described, is transmitted. This is apparent from the fact that for those units in which the switch is open, it will then be closed after a signal of six-minute duration has been received, and for those receivers which are already closed no change will be made as the cam l2 for the last mentioned receivers will merely move through an angular distance of 36 less than that required to open the switch from its closed position as shown in Figure 2.

In the actual construction of the device it is preferable to make the first cam I2 and the holding or toothed wheel or second cam l3 of fiber, Baelite, or other suitable insulating material.

While the invention has been described as applied to remote controlled devices for use in systems controlled by carrier current of a predetermined frequency, it is to be understood that the remote controlled switch forming the subject matter of this invention can be controlled remotely in other ways, for example, by means of a pilot line leading to such switch or switches.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. In a remote controlled switch adapted to selectively respond to energizations lasting for different periods of time, a self-starting synchronous motor, switch operating means driven thereby, a normally open magnetic clutch between said motor and said switch operating means arranged to close when said motor is energized, switch means operated from said switch operating means, said switch operating means including a cam provided with a series of teeth arranged in pairs of unequal length and with faces slanting inwardly towards the center of said cam and terminating in seating portions defining initial or zero starting positions for each operation of said switch means, an inwardly biased cam follower coacting with said slanting faces and biasing said cam towards rotation in a reverse direction from that imparted to said cam by said motor to seat said cam follower in the corresponding seating portion upon deenergization of.

said motor and release of said clutch, and a second cam operated from said first cam and directly operating said switch means and having raised and depressed portions of different lengths corresponding to the different lengths of the teeth of the first mentioned cam.

2. In a remote controlled switch adapted to selectively respond to energizations lasting for different periods of time. a self-starting synchronous motor, switch operating means driven thereby, a normally open magnetic clutch between said motor and said switch operating means arranged to close when said motor is energized, switch means operated from said switch operating means, said switch operating means including a first cam provided with a series of teeth arranged in pairs of unequal length and with faces slanting inwardly towards the center of said cam and terminating in seating portions defining initial or zero starting positions for each operation of said switch means, said switch operating means also including a second cam driven from said first cam and having limited movement with respect to said first cam and having a series of teeth arranged to engage said switch means to move said switch means in one direction separated by spaces, said teeth and spaces being of unequal lengths corresponding to the unequal lengths of the teeth of said first cam, said switch means being biased towards motion in the other direction, and an inwardly biased cam follower coacting with said slanting faces and biasing said cam towards rotation in a reverse direction from that imparted to said cam by said motor to seat said cam follower in the corresponding seating portion upon deenergization of said motor and release of said clutch.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 708,007 Ball Sept. 2, 1902 990,285 Moyer Apr. 25, 1911 1,020,185 Bullard et a1 Mar. 12, 1912 1,213,799 Perrin Jan. 23, 1917 1,483,433 Hall Feb. 12, 1924 1,575,010 Scheer Mar. 2, 1926 1,941,377 Woodworth Dec. 26, 1933 1,986,032 Townsend Jan. 1, 1935 2,010,705 Stark Aug. 6, 1935 2,030,890 Oberhofiken Feb. 18, 1936 2,142,341 Arnold Jan. 3, 1939 2,183,653 Miller Dec. 19, 1939 2,269,246 Bloomfield Jan. 6, 1942 2,488,110 Aitken Nov. 15, 1949 FOREIGN PATENTS Number Country Date 906,216 France May 7, 1945