US2593727A

US2593727A - Electric circuit timing switch

Info

Publication number: US2593727A
Application number: US65896A
Authority: US
Inventors: Clarence J Cadwell; Frank M Adamson
Original assignee: CADWELL CORP
Current assignee: CADWELL Corp
Priority date: 1948-12-17
Filing date: 1948-12-17
Publication date: 1952-04-22
Anticipated expiration: 1969-04-22

Description

April 22, 1952 c. J. CADWELL ETAL 2,593,727

ELECTRIC CIRCUIT TIMING SWITCH Filed Dec. 17, 1948 2 SHEETS-SHEET 2 gvwmbo'bs' Clarence dla a u ell Fla/1k Hfidawzsan {PH WW Patented Apr. 22, 1952 ELECTRIC CIRCUIT TIMING SWITCH Clarence J. Cadwell, Carpinteria, and Frank M. Adamson, Los Angeles, Calif., assignors to The Cadwell Corporation, Beverly Hills, Calif., a corporation of California Application December 17, 1948, Serial No. 65,896

2 Claims.

This invention relates generally to the class of circuit makers and breakers and itis directed particularly to a device of this character which is time operated.

A principal object of the present invention is to provide an improved electric circuit timing switch wherein novel means is provided for changing the timing periods or operating frequency of the switch.

Another object of the invention is to provide an electric circuit timing switch in which the timing periods may be easily and quickly changed so that the switch may be employed for a period of time for closing a circuit at intervals of say one second and may then be employed for another period of time for closing the circuit at intervals of a half second or a quarter second or any other time frequency.

A further and more specific object of the invention is to provide a circuit controlling device in which a series of concentric constantly rotating toothed elements is employed in association with a circuit making and breaking unit which is shiftably positioned adjacent to the toothed elements whereby the unit may be brought into any one of a number of selected positions to cause a selected one of the toothed elements to periodically actuate the switch.

A further and more specific object of the invention is to provide an easily and quickly changed timing mechanism designed particularly for use in association with still picture projecting machines for controlling the operation of the electrically operated mechanism by which the pictures are changed, whereby the changing of the pictures may be made to occur at intervals of one minute, half minute, quarter minute or any other selected interval.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming a part of the specification, with the understanding, however, that the invention is not to be limited to the exact details of construction shown and described since obvious modifications will occur to a person skilled in the art.

In the drawings:

Figure 1 is a view in top plan of a projector to one side of which is secured a timer switch constructed in accordance with the present invention.

Figure 2 is a view in front plan of the timer switch structure.

Figure 3 is a view in side elevation of the same.

Figure 4 is a sectional view taken substantially on the line 4-4 of Figure 2,-the parts to the rear of the body plate being omitted.

Figure 5 is a detailed section taken substantially on the line 5-5 of Figure 3.

Figure 6 illustrates the circuit diagram for the mechanism.

Figure 7 is a section on the line 1-1 of Figure 2 through the switch supporting cradle and the lever, the body of the switch being in elevation.

The electric circuit timing switch mechanism of the present invention is herein disclosed as mounted upon or coupled with a picture projecting machine of the type in which a number of picture plates are stacked in a predetermined position and are successively and periodically moved by an electrically operated motor into projecting position. However, it is to be understood that this timing switch mechanism is adaptable to many other uses in connection with the periodic opening and closing of an electric circuit and accordingly in showing and describing it in association with a picture projector there is no intention of limiting its use in this manner.

In the drawings the numeral In generally designates a still picture projecting machine ofa well known type designed for the projection of pictures of 35 mm. size. This machine is provided with a manual lever I l whereby manual changing of the pictures may be accomplished if desired or such changing of the pictures may be electrically effected by means of a push button control, not shown, but which is connected with a current carrying cable 12, whereby an electric motor within the machine, when energized, effects the automatic transfer of a picture from a group stacked in a receiver l3 upon the top of the machine, to a position for projection through the lens barrel l5. Simultaneously with this operation, the picture previously on display, if any, is shifted into a bottom receiver not shown. This mechanism is all of standard well known construction and accordingly it is not believed that it requires illustration or further description for proper understanding by those familiar with still picture projectors of the type under consideration.

The body or housing of the machine has an outwardly and downwardly extending bottom flange or skirt l6 and the machine stands on supporting feet, not shown, so that the bottom edge of this flange is elevated from the underlying surface upon which the machine is supported. The mechanism of the present invention is mounted on an upstanding plate [8 which is disposed at 3 one side of the projection machine as shown in Figure 1, and is secured in position by a clamp l9 which grips the bottom edge of the flange I6 as illustrated in Figure 3.

Secured to one face of the plate l8, which will be defined as the back face, is a synchronous motor which is generally designated and which has a shaft 2| which is extended through the plate It to a substantial distance beyond the front face thereof. This motor i of the type which is suitably back geared to turn theshaft at one revolution per minute.

Secured to the shaft 2| at the front side of the mounting plate I8 is a sleeve 22. This sleeve is maintained on the shaft against rotation by means of a set screw 23 or in any other suitable manner and at the back end of the sleeve is an encircling flange 24. The bore 25 of the sleeve 22 is threaded at its forward end as indicated at 26 and the shaft 2| terminatesin thebore short of this threaded portion as shown in Figure 4.

Mounted upon the sleeve 22 is a series of timing wheels 2i, three being here shown. These wheels are in abutting relation one with the other and the rearmost one bears against the flange 24. The timing wheels are maintained in place by the cap 28 which is centrally apertured to have a screw 29 extended therethrough and threaded into the forward end of the bore 25 so that the cap 28 bears against the outermost timing wheel.

The timing wheels are provided around their peripheries with spaced spurs or teeth 21' and the spacing of the spurs upon each wheel is different from that of the spurs on each of the other wheels. Accordingly one wheel may have two equally paced spurs and the next wheel four and the next six or eight so that the wheels may function as half minute, quarter minute or sixth minute timing wheels for the switch hereinafter described.

By the provision of a number of these wheels having teeth at differently spaced intervals timing of the mechanism can be altered by changing the wheel to set up different groups thereof.

Disposed on one side of the timing wheels 21, here shown as upon the underside thereof, are the two spaced parallel arms 30. These arms are secured to the plate l8 and pass freely through the insulation body 3| of an electric circuit controlling switch which is generally designated 32 and which is of a type having a pivotally mounted tongue or blade 33 having one end curved upwardly as shown. This switch 32 is placed so that the upwardly curved end of the switch blade 33 will be in the path of movement of the teeth 21' of one of the wheels 21.

The switch 32 has the two terminals 34 for the connection of

electric conductors

35 and 36 thereto, which conductors are put into electrical connection when the tongue 33 is depressed.

Mounted upon the plate l8 below the switch 32 is a supporting body 31 upon which is secured the platform 38. One end of this platform exone end of the lever is positioned beneath the switch 32 to which it is pivotally coupled by means of the pivot bolt 43 and the cradle 44. As shown this cradle receives the body of the switch 32 and the bolt 43 is pivotally connected to the bottom part of the cradle and to the adjacent end of the lever 4|.

The opposite or outer end of the lever 4| carries an upstanding post 45 by means of which the oscillation of the lever about the pivot 42 is facilitated. Beneath the lever 4| and directly below the post 45 is a button 45 which is adapted to engagev in one of the depressions 40 when the lever is swung to any one of the three positions necessary for properly locating the switch 32 beneath a selected toothed timing wheel 21.

The cradle 44 is substantially U-shaped as shown in Figure 4, and the body 3| of the switch 32 rests therein and is adapted to have slight sliding movement so that the necessary swinging of the cradle and the inner end of the lever 4| may take place while the switch moves in a straight line or path transversely of the lever.

The synchronous motor 20 includes the usual coil or winding C and the flow of electric current from the source to this motor and through the switch 32 to the picture or slide changing motor of the projector machine, is under the control of the toggle switch 46 which is mounted in a suitable convenient position, preferably upon the top of the plate l8 as here illustrated.

In the circuit diagram forming Figure 6 the slide changer motor which is housed within the machine ID, is diagrammatically illustrated and designated 41 and in this diagram the numeral 48 designates one of two separable couplings by means of which necessary current conductors are joined together, the other one of the couplings being designated 48. The coupling 48 which has wire connections directly with the synchronous motor 20, the switch 32 and the control switch 46 may be mounted directly uponthe side of the plate |8 as shown in Figure 2, while the other coupling section 48' is connected with the cables |2 which are in turn connected with the changer motor 41 and with the wires or conductors by which the current is fed in from a source and returned, such conductors being designated 49.

As will be readily seen upon reference to the circuit diagram, when the conductors are coupled together by the coupling units 48 and 48', electric current from the source will be carried to the terminal a where it will be divided to flow through the conductors a, b, the conductor a leading to one side of the synchronous motor coil C and from the other side of this coil through conductor 11 to a terminal a: of the switch 46. The conductor 1) leads to a terminal y of the toggle switch 48. A second terminal b is electrically connected by conductor 35, with one side of the normally open switch 32 and the other side of this switch is connected by the conductor 36 with a terminal y of the toggle switch 46. The fourth terminal :0 of this toggle switch is connected by the return conductor d with the third terminal 0 of the connector 48. When the

parts

48 and 48 are connected together the terminal I) will be electrically connected with the terminal b which is electrically connected with one side of the slide changer motor 41, the other side of the motor being connected to the return lead as illustrated. a

The switch 46 is of a type designed for the control of parallel circuits and particularly of the slow-make, slow-break type such as that illustrated in the patent to Krieger No. 2,133,545. This switch has a control or toggle arm 45' which actuates a pair of contactors e, e which are electrically insulated from one another. The contactor 2 electrically connects the terminals x, at and the contactor e" electrically connects the terminals y, y" when the arm 48 is oscillated in one direction so as to simultaneously close the circuit through the synchronous motor coil C and to prepare the circuit in which the switch 32 is connected so that when the switch 32 is closed the slide changer motor will be energized.

As will be readily understood from the foregoing when the switch 46 is closed the synchronous motor 20 Will be set into operation and the timing wheels will be rotated at a speed of one revolution per minute. By actuating the pivoted lever 4| the switch 32 may be shifted in or out so as to bring it into desired position to be periodically closed by the spurs of the selected one of the wheels 21. Thus with the arrangement here illustrated if the lever 4| is shifted in a direction to move the switch 32 inwardly toward the plate IS the innermost wheel 21 having the two equidistantly spaced spurs 2'! will close the switch 32 at half minute intervals. If the switch 32 is set in the center position where the switch blade will be periodically depressed by the spurs of the center wheel, which spurs are four in number and equidistantly spaced then the switch 32 will be closed at quarter minute or fifteen second intervals and the picture motor will be correspondingly operated to change the pictures of the projector at such intervals.

We claim:

1. In an electric circuit timing switch, a substantially rectangular body of an insulating material having a channel in its upper side, a pair of opposed contact elements fixedly mounted in the side walls of said channel toward an end thereof, a tongue of spring metal within said channel and having one end secured toward the opposite end of the channel and its other end upwardly curved and overlying said contact elements, a shaft extending transversely of and above said body, rotary elements mounted on said shaft and having their peripheries each provided with a series of spurs, and means for shifting said body relatively to said rotary elements to selectively position said tongue in the paths of movement of the spurs, whereby the curved end of the tongue will be depressed into bridging relation with respect to said contact elements, the spurs on each of said rotary elements being differently spaced to vary the timing operation of the spring tongue.

2. In a still picture projector, including its casing and an electric motor operated slide changer, a bracket adapted to be detachably mounted on said casing, a plate supported vertically on said bracket, a horizontal platform mounted on the outer side of said plate toward its lower end, a laterally shiftable member mounted on the upper side of said platform, a body of an insulating material supported on said shiftable member and having a channel in its top side extending parallel to said plate, a pair of opposed contact elements mounted in the side walls of said channel toward an end thereof, a tongue of spring metal within said channel and having one end secured toward the opposite end of the channel and its other end upwardly curved and overlying said contact elements, an electric motor mounted on the inner side of said plate and having its shaft extending through the plate above said body, rotary elements mounted on the extended end of said shaft and having their peripheries each provided with a series of spurs, and a hand lever for moving said shiftable member and said body relatively to said rotary elements to selectively position said tongue in the paths of movement of the spurs, whereby the curved end of said tongue will be depressed into bridging relation with respect to said contact elements, the spurs on each of said rotary elements being differently spaced to vary the timing operation of said spring tongue.

CLARENCE J. CADWELL. FRANK M. ADAMSON.

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

UNITED STATES PATENTS Number Name Date 1,984,302 De Vries Dec. 11, 1934 2,360,179 Urbas et a1. Oct. 10, 1944 2,371,378 Clark Mar. 13, 1945