US2677732A - Time switch - Google Patents

Description

May 4, 1954 Filed Sept. 18, 1946 W. R. MILLER TIME SWITCH 2 Sheets-Sheet l 55 p 23 Al/il T HVVENTUR. 71F. a7/9m/JQ, 0717/5? BY ATTORNEY y 4, 1954 w. R. MILLER 2,677,732

TIME SWITCH 2 Sheets-Sheet 2 Filed Sept. 18, 1946 IN VEN TOR.

Maya/Amy BY f a ATTORNEY Patented May 4, 1954 UNITED STATES PATENT OFFICE 16 Claims. 1

This invention relates in general to automatic controls and is more particularly concerned with timing devices.

The primary object of this invention is to provide a time switch or control which performs a plurality of different switching operations in a predetermined sequence and in which the de--' sired times of operation may be easily set by an untrained user.

A further object of the invention is to provide a device of the above character which is extremely simple and rugged in construction and which is easy to understand and use.

Other objects will become apparent from the following description and the appended claims.

For a full disclosure of my invention, reference is made to the following description and the accompanying drawings in which Fig. 1 is a front View of a timer embodying the present invention;

Fig. 2 is a side view partially in section of the device shown in Fig. 1;

Figs. 3, 4 and 5 are a series of fragmentary views showing different operating positions of the actuating cam for the cam shaft;

Figs. 6, '7 and 8 are a series of fragmentary views showing positions of the cam shaft and switch mechanism corresponding to Figs. 3, 4 and 5 respectively;

Fig. 9 is a wiring diagram showing one application of this embodiment of the invention;

Fig. 10 is a front view of a modified form of the invention for a different application or use;

Fig. 11 is a side view of Fig. 10, partially in section;

Fig. 12 is a view of the timer behind the panel showing the switches and operating mechanism therefor, and

Figure 13 is a wiring diagram showing an application for this form of the invention.

For subject matter disclosed but not claimed in this application, reference is made to my copending application Serial No. 697,815, filed September 1S, 1946, now Patent No. 2,633,508, dated March 31, 1953.

Referring to Figure 1, reference character I indicates a panel which is mounted in a suitable enclosure 2, having a hinged cover 3, by means of screws 4 which are threaded into suitable mounting brackets on the enclosure at the rear of the panel. The panel I at its upper end carries a synchronous motor and gear train mechanism 5, this mechanism having a final drive shaft extending through the panel to which a hub 6 is attached. The hub member in the embodiment shown carries a 24-hour dial 1, an on actuator 8, an automatic actuator 9 and an off actuator l0. As shown in Figure 2 the actuators 8, 9 and ill have flat generally circular portions located behind the dial and also have finger like portions extending beyond the dial as appear in Figure l. The dial and actuators are provided with holes through which the hub extends, the holes being slightly larger than the hub so that the dial and actuators are free to turn thereon. A screw ll holds a front friction plate I2 firmly against the front of the hub, this plate serving to provide friction between the hub and the front surface of the dial. A friction spring I3 is located behind the rearmost actuator and bears against a rear friction plate or cupped washer M which abuts a shoulder on the hub member 6. With this arrangement the dial and the three actuators are clamped between the front friction plate and the friction spring, this providing a friction drive between the hub and the dial and actuators. With this friction drive the dial may be set on the hub for the correct time as indicated by the time arrow l5 on the front panel. Also, with this arrangement the actuators may be readily adjusted on the dial for the desired times of switch operation.

Located below the dial is a cam shaft l8. This shaft extends freely through a hole in the panel I and the rear end is supported by a screw I9 which extends loosely through a rear plate 20. A friction washer 2| is interposed between the rear end of the shaft l8 and the plate 20 for providing a slight amount of resistance to turning of the shaft l8. Located below the shaft l8 are a pair of enclosed snap switches 23 and 24. These switches are of a type Well known in the art, the switch 23 having a spring pressed plunger 25 and the switch 24 having a similar plunger 26. The switches 23 and 24 are held in place on the panel by means of screws 21 and 28 which extend through suitable mounting holes in the switch enclosures and which also extend through suitable holes in the rear plate 20. The screws 21 and 28, therefore, serve to mount both switches and the rear plate 20 rigidly to the front panel I. The shaft I8 is generally round but is provided with two fiat chord-like sections or segments 30 and 3|. The fiat section 30 is located on the right hand side of the shaft as seen in Figure 6 and is adjacent the operating plunger 26 of the snap switch 24. The fiat section 3| is on the left side of the shaft and is located opposite the plunger 25 of the snap switch 23 as will be seen in Figure 6. The flat sections are angularly located on the shaft so as to provide an intermediate or neutral section 32 wherein both plungers and 26 are depressed.

Attached to the front end of the cam shaft is a cam member 35. This cam member as indi cated in Figure 3 is provided with an upper engaging surface 36 and a lower engaging surface 31. The cam member is also formed as a pointer and cooperates with indicia 33 on the front panel for indicating the position of the cam shaft. The cam 35 is operated by the actuators 3, 9 and Ill. To this end the actuators are provided with rearwardly extending ears which are punched from the material of the actuators. Thus the automatic actuator is provided with cars 39 and 40,

the off actuator is provided with an ear 4|, and the on actuator is provided with an car 52.

When the off actuator 10 passes the cam 35, the ear ll on this actuator engages the lower surface 3'] of the cam and causes rotation of the cam to the position indicated as off. At this time the ear ii rides off the end of the surface 3'? and the actuator remains in this position. When the on actuator passes the cam 35, the car 42 on this actuator engages the upper operating surface of the cam 3%, this causing counterclockwise rotation of the cam and its shaft to the position indicated as on. When the cam reaches this position the actuator 42 rides off the end of the surface 36 of the cam and the cam thus remains in the on position. When the automatic actuator Q passes the cam the cars 39 and ill engage the top and bottom surfaces of the cam and thus move it to the center or automatic position. This action occurs irrespective of whether the cam was at off or on at the time it is engaged by the automatic actuator.

One important application for the time switch above described is for day-night control of heating systems for large buildings which are controlled by weather controls rather than by inside thermostats. In this type of installation, the heating system is shut 01f entirely at night and is returned to the control of the weather control in the morning. The weather control, however, does not respond to the temperature of the building and would function merely to supply enough heat to balance the heat loss from the building. With this type of system it is therefore necessary to provide a constant on period in the morning during which the stoker or oil burner operates independently of the weather control for bringing the building temperature back to normal. When the time switch above described is to be used in this type of system, the switch 23 is made normally closed and the switch 24 is made normally open. In other words, when the plunger 25 of the switch 23 is in its outer position the switch is closed and when this plunger is depressed the switch opens. When the plunger of switch 24 is in its outer position the con tacts are open and when the plunger is depressed the contacts close.

Figure 9 indicates a wiring diagram showing the hookup for the above described installation. The stoker or oil burner motor is controlled by a motor starter 5i having control terminals 52 and 53. The terminal 52 is connected to a manual switch 5d which may be mounted on the panel i below the snap switches. The other side of switch 54 is connected to one terminal on both the switch 23 and switch 24. The switch 23 is connected directly to the terminal 53 of the motor starter by wire 55 and the switch 24 is 4 wired in series with the weather control 56 which is also connected with the terminal 53 of the motor starter.

During the day the cam 35 is in its intermediate or automatic position, shown in Figure 3. At this time the cam shaft is in the position shown in Figure 6 is which both snap switch plungers are depressed. As the switch 23 is of the normally closed variety, the depressed plunger of this switch causes it to be in open position. As the switch 24 is of the normally open variety the depressed plunger 25 causes this switch to be closed. Assuming the manual switch 5 3 is closed the burner is then under the control of the temperature or weather control 56 which starts and stops the burner in proportion to the heating load.

At night the oif actuator passes the cam 35 and actuates it to the off position as shown in Figure 4. This causes the cam shaft is to assume the position shown in Figure 7, in which the plunger 26 of snap switch 2:3 is in its outer position causing this switch to be open. The plunger 25 of the switch 23 has remained at its inner position and this switch is therefor also open. Due to both switches 23 and 24 being open, the temperature control 56 cannot start the burner and the heat is thus off for the night.

The on actuator would be set on the dial to approximately 6:00 a. m. and would thus pass the cam 35 at this time. This will move the cam 35 from the off position as shown in Figure 4 to the on position as shown in Figure 5. At this time the cam shaft It will assume the positicn shown in Figure 8 in which the plunger 26 of snap switch 24 is depressed and the plunger 2%; of switch 23 is in its outer position. These positions of the plungers cause both switches 23 and 24 to be closed. The switch 21% shunts out the temperature control 56 and thus provides for constant operation of the burner irrespective of the temperature control 56.

The automatic actuator would be set on the dial for approximately 7:30 a. m. At this time the automatic actuator passes cam 35 causing it to assume the position as shown in Figure 3 this causing the cam shaft to assume the position shown in Figure 6. As previously pointed out this position of the cam shaft causes the switch 23 to be open and the switch 24 to be closed thus providing for automatic control of the burner by the temperature control 56.

From the foregoing description it will be apparent that the present invention provides a simple and easily adjusted control for operating the switches 23 and 2-1 in the proper sequence for obtaining the desired results. It should be noted that due to the actuator construction in which the ears on one actuator prevent the passing of another actuator the actuators once assembled properly will always be in the proper sequence, and it is impossible for the user to get the fingers adjusted in the wrong sequence.

Referring to Figures 10, ll, 12 and 23 these figures show the application of the invention to a special timer for use in poultry houses. In this application, the invention serves to turn the lights from off to dim in the morning. After a timed period the lights turn from dim to bright. The lights then remain on bright until it is desired for them to go off. The lights go from bright to off directly without going through a dimming period. At night when lights are desired, the lights turn from off to bright directly and remain on bright until it is desired for them to go oif. At this time the lights change from bright to dim, remaining dim for a timed period, and then go off.

Referring to the particular construction, a panel 68 serves to support a motor and gear train mechanism generally indicated as 6!. V The gear train has a final drive shaft [i2 which extends through the panel 60 and which is attached to a hub member ti. This hub member carries a dial 83, an on-a. m. actuator 64, an off-a. m. actuator 65, an on-p. in. actuator G2 and an oil-p. m. actuator 61. The dial and actuators are freely mounted on the reduced portion of the hub and are clamped between a front friction plate 68 and a friction spring 69 which abuts a rear friction plate 10 which in turn abuts a shoulder on the hub memher. The dial and actuators are thus yieldably held on the hub and may be adjusted on the hub independently of each other. The actuators 64, 65, 36 and 6'? are each provided with inwardly extending ears for operating a cam member '13 which is mounted on a cam shaft l4 extending through the panel 69. The rear end of this shaft is supported by a screw which loosely fits through a hole in the gear train plate H3. As shown in Figure 11, cam shaft 14 has a rear portion '5? which is hexagon shaped and a front portion i8 which is circular and which extends through the panel 60. The rear or hexagon portion of the cam shaft supports a switch operating cam 89 which serves to actuate over center type snap switches 82 and 82.

The snap switch 81 includes a base portion 83 which is mounted on a mounting plate 84 by screws at. The plate 54 as shown in Figure 11 is supported from the lower end of the plate [6 which supports the synchronous motor and a portion of the gear train. Embedded in the base portion 83 of the snap switch is a stifi switch blade 88 carrying a stationary contact at its upper end. This blade 38 is attached to a wiring lug 8d protruding from the bottom of the base 83. Also supported in the base 23 is a flexible blade 96 which carries a contact for cooperating with the contact first mentioned. The lower end of the flexible blade is attached to a wiring lug 9!; which is in turn attached to a lead 92 which passes through a hole in the base 84. The snap switch also includes a spring operating member the lower end of which is mounted in the base 83 and which extends upwardly adjacent the cam The upper end of the operating member as is bent over and is provided with a tongue engaging a G-spring 9d. The other end of the d spring Gd is engaged by a protruding tongue in the flexible switch blade 90. The switch 8i also includes a stop blade 96 which extends upwardly and is provided with a button adapted to be engaged by the contact on the flexible blade 99. When the blade 93 is in the position shown, the C-spring 94 provides a component of force which holds the flexible blade til against the stop blade 96 this causing 'the switch contacts to be open. When the spring operating member 93 is pressed to the right against its bias, the point of support for the upper end of the C-spring 94 is shifted to the right which eventuall causes a component of force urging the spring contact blade 96 to the left for engaging the contacts. Thus movement of the operating member 93 to the right causes the contacts to engage with snap action and movement of this operating member to the left causes the contacts to disengage with snap action.

The snap switch 82 is similar to the switch 8| but is of the double throw type. In other words, this switch is provided with 2 sets of contacts 98 and 99. When the spring operating member Hill is moved to the left the contacts 99 disengage and contacts 98 engage. When the spring operating member moves to the right the reverse action takes place. It will be understood that the engagement and disengagement takes place with snap action in both directions.

Figure 13 shows one form of installation of the poultry house timer. It will be seen that the on-off switch 5i is connected to the hot line I02 and the other side of the switch is connected to the common blade of the switch 82. The contact 9:) of switch $2 is connected to a resistance bank His and the contact 98 of switch 82 is connected directly to the main lamp bank I04, the other side of which is connected to the ground line I95.

With the parts in the position shown the cam I3 is in the position marked p. m.--ofi which causes the switch operating cam to be in the position shown in Figure 12. In this position the operating member 93 of the switch BI is at its extreme left position which causes the switch 8! to be open. The operating member I00 of the switch 82 is in its right hand position which has caused the common blade of switch 82 to engage contact 99. Due to the switch 8| being opened the lights are out. As the ona. m. actuator 64 rotates past the cam 13, the car on this actuator will engage the lower operating surfaces IQ? of the cam 13 thereby rotating the cam shaft clockwise. The first action that takes place is for the protrusion i538 of cam 88 to urge the switch operating member 93 to the right for causing the switch 8| to snap to its closed position. This establishes a circuit through switch 8! contacts as of switch 32, resistance bank I03, and lamp bank ltd to the ground line m5. The resistance bank IE3 is thus in series with the main lamp bank with the result that the main lamp bank burns dimly. On continued rotation of the dial assembly (approximately 15 minutes) the on-a. in. actuator will continue to rotate the cam shaft 74 clockwise until the cam '13 reaches a position between the words dim and bright on the panel 69. At this time the protrusion 209 on the cam 80 has engaged the operating member I00 of switch 32 and has shifted this operating member far enough to the left to cause this switch to snap, thus disengaging contact 9% and engaging contact 88. This shunts out the resistance bank I93 and thus causes the main lamp bank to burn at full brilliance. When the cam 13 reaches a position opposite the word bright the ear on the actuator t l disengages the lower operating surface It": of the cam and the cam shaft remains stationary in this position. At this time the protrusions 38 and its on the cam are on a line passing horizontally through the axis of the cam shaft. Thus the inward spring effects of the operating members 98 and Hill are balanced out and the cam shaft remains stationary in this position. When the a. m.- oif actuator 65 passes the cam the ear on this actuator engages the cam by reason of the fact that this ear is located closer to the axis of rotation of the dial assembly of the corresponding ear on the actuator 84. Engagement of the actuator 65 with the cam 13 causes thecam shaft to continue rotating in a clockwise direction until it reaches the position a. m.-oif. At

7 this time the protrusion its on the cam at has moved downwardly to a point at which it permits movement of the operating member 93 to the left as the cam rotates clockwise. The switch 8| thus snaps to open position. The lights, therefore, at this time go directly from bright to off.

In the evening the onp. m. actuator passes the cam 13 and an car on this actuator engages the upper surface III of the cam I3 and causes the cam to travel from the position a. m.-off to bright. During this movement the protrusion I88 on the cam 85 has travelled upwardly and outwardly thereby urging the switch operating member 93 to the right for causing switch 8| to close. At this time the switch 82 has already been positioned to engage contact 98. Therefore, when switch 8| closes, the circuit is completed directly to the main lamp bank for causing it to burn at full brilliance. The ear on the on-p. m. actuator 66 disengages the cam 13 in the bright position and the lights thus stay on bright until the cam is engaged by the offp .m. actuator 31. The ear on this off-p. actuator engages the upper surface of cam is and causes the cam to travel counterclockwise from bright to p. m.-off. As the cam travels between the words bright and dim on the panel, the protrusion 09 on the 80 moves away from the switch operating member liit thus permitting this switch to return to the position shown in Figure 3 in which the contacts are engaged. The lamps at this time, therefore, burn at dim. As the dial assembly continues to rotate (approximately 15 minutes) it rotates the cam 13 to the p. m.--off position shown in Figure 12 at which time the switch iii opens and turns out the lights.

It will be noted that the cam Bil is formed with an extension H2. This extension provides surfaces adapted to engage the upper portions of the operating members 93 and Hill. This provides a stop for the cam shaft Hi and limits its rotation so that it cannot be moved to a position in which it cannot be picked up by the ears on the actuators.

From the foregoing description it will be apparent that the present invention provides a simple mechanism for operating a plurality of switches or control devices in predetermined or specified manner and which is readily adjusted and understood by the user. It will also be apparent that the invention provides a flexible mechanism which may be readily adapted to perform a number of specialized functions. While I have shown and described only two embodiments of the invention it will be understood that many variations may be made without departing from the spirit and scope of the invention. It is therefore desired to be limited only by the scope of the appended claims.

What is claimed is:

l. a time control, the combination of, a timing motor, a plurality of control devices, means including cam means having segments arranged to actuate said control devices separately in a predetermined sequence, and means including a series of actuators moved by said timing motor for operating said cam means in a predetermined sequence, one of said actuators being constructed and arranged to move said cam means in one direction and another actuator be ing constructed and arranged to move said cam means in the opposite direction.

2. In a time control, the combination of, a timing motor, a plurality of individually operable control devices, means including a common operating member for operating said control devices separately in a predetermined sequence upon movement of said operating member, and means including a series of actuators movable by said timing motor for moving said operating memher to predetermined positions at predetermined times, one of said actuators being constructed and arranged to move the operating member in one direction and another actuator being constructed aand arranged to move the operating member in the opposite direction.

3. In a time control, the combination of, a timing motor, a plurality of individually operable control devices, means including a cam shaft having segments arranged to actuate said control devices in a predetermined sequence upon rotation of said cam shaft, and means including a series of actuators rotated by said timing motor for rotating said cam shaft to predetermined angular positions at predetermined times, one of actuators being constructed and arranged to rotate the cam shaft in one direction and another of said actuators being constructed and arranged to rotate the cam shaft in the opposite direction.

i. In a time control, the combination of, a timing motor, a cam shaft, a plurality of individually operable control devices, said control devices each having an operating member biased against said cam shaft, and means including a plurality of actuators moved by said timing motor for moving said cam shaft to predetermined positions at predetermined times, one of said actuators being constructed and arranged to move said cam shaft in one direction and another of said actuators being constructed and arranged to move the cam shaft in the opposite direction.

5. In a time switch mechanism, the combination of, a timing motor, a drive shaft rotated by the timing motor, a earn shaft spaced from the drive shaft and substantially parallel with the drive shaft, a plurality of switches arranged to be operated by said cam shaft in a predetermined sequence upon rotation of said cam shaft, a plurality of individually adjustable actuators mounted on said drive shaft and extending therefrom, and engaged by said actuators for rotating said cam shaft to predetermined angular positions, one of said actuators being constructed and arranged to rotate the cam shaft in one direction and another of said actuators being constructed and arranged to rotate the cam shaft in the opposite direction.

6. In a time switch mechanism, the combination of, a timing motor, a drive shaft rotated by the timing motor, a cam shaft spaced from the drive shaft and substantially parallel with the drive shaft, a plurality of individually operable switches, said cam shat having cam surfaces arranged to operate said switches separately and in a predetermined sequence upon rotation of the cam shaft, actuating cam means on the cam shaft and having a first engageable portion on one side of the shaft and a second engageable portion on the other side of the shaft, and a plurality of individually adjustable actuators mounted on the drive shaft for rotating the cam shaft to predetermined positions at predetermined times, one of said actuators engaging one of said engageable portions of the cam means for rotating the cam shaft in one direction and another of said actuators engaging the other of said engageable portion of the cam means for rotating the cam shaft in the opposite direction.

'7. A device as set forth in claim 6 in which the cam means is formed to provide an indicator for the shaft position, and indicia cooperating with said indicator for indicating the effective positions of said switches.

8. In a time switch mechanism the combination of a timing motor, switching mechanism having at least three different combinations of contact positions, an operating member for said switching mechanism, said operating member having a first position providing a first combination of contact positions, a second position providing a second combination of contact positions, and an intermediate position providing a third combination of contact positions, and a plurality of actuators driven by said timing motor, one of said actuators being constructed and arranged to-move said operating member in one direction to one of said positions and another of said actuators being constructed and arranged to move said operating member in the opposite direction to another of said positions. 9. In. a time switch mechanism the combination of a timing motor, switching mechanism having at least three different combinations of contact positions, and operating member for said switching mechanism, said operating memher having a first position providing a first combination of contact positions, a second position providing a second combination of contact positions, and an intermediate position providing a third combination of contact positions, and at least three separate actuators driven by said timing motor, one of said actuators moving said operating member in one direction to said first position, another actuator moving the operating member in the opposite direction to said second position, and the third actuator moving said operating member only to said intermediate position.

10. In a time switch mechanism especially adapted for controlling heating systems having an automatic cycling control for controlling heat output in accordance with weather load, the combination, of switching mechanism providing an off position, an on position, and an automatic position, a timing motor, and three separate individually adjustable actuators driven by the timing motor, the first of said actuators being arranged to move the switching mechanism to the off position, the second of the actuators being arranged to move the switching mechanism to the on position, and the third of said actuators being arranged to move the switching mechanism to the automatic position, in the sequence specified.

11. In a time switch mechanism, the combination of a timing motor, a switching mechanism, a rotatable shaft for operating said switching mechanism upon rotation thereof, said shaft having two terminal positions and an intermediate position, cam means for rotating said shaft, a first actuator driven by the motor and adapted to engage the cam means for rotating the shaft to one of its terminal positions, a second actuator driven by the motor and adapted to engage the cam means for rotating the shaft to its other terminal position, and a third actuator driven by the motor and adapted to engage the cam means, said third actuator being constructed and arranged to actuate the cam means to move said shaft to said intermediate position.

12. In a time switch mechanism, the combination of a timing motor, a switching mechanism, a rotatable shaft for operating said switching mechanism upon rotation thereof, said shaft having two terminal positions and an intermediate position, cam means for rotating said shaft, a first actuator driven by the motor and adapted to engagethe cam means for rotating the shaft to one of its terminal positions, a second actuator driven by the motor and adapted to engage the cam means for rotating the shaft to its other terminal position, and a third actuator driven by the motor, said third actuator having a first abutment adapted to engage the cam means for moving the shaft from one of its terminal positions to an intermediate position and having a second abutment means adapted to engage the cam means for moving the shaft from the other of its terminal positions to an intermediate position.

13. In a time switch especially adapted for poultry houses the combination of, switching mechanism including a movable operating element therefore movable between two terminal positions, said element and switching mechanism being constructed and arranged to provide an on to off switching operation as the operating element is moved to either of its terminal positions, and being further constructed and arranged to provide a bright-dim switching operation intermediate said terminal positions, a timing motor, means including a first actuator driven by the timing motor for shifting the element from one of its terminal positions past said intermediate position to an intermediate stopping position, a second motor driven actuator for shifting said element from said stopping position to the other terminal position, a third motor driven actuator for shifting the element from the latter terminal position back to said intermediate stopping position, and a fourth motor driven actuator for shifting the element back to the initial terminal position.

14. In a time switch mechanism, a timing motor, a pair of switches, a cam shaft for operating said switches, and cam shaft being rotatable between two terminal positions and having cam surfaces arranged to close one of said switches upon rotation from either terminal position and to open said one switch at either terminal position, said cam shaft also having cam surfaces arranged to operate the other of said switches intermediate its travel between said terminal positions and means operated by the timer motor for rotating said cam shaft from one of said terminal positions to the other.

15. In a time switch mechanism, a timing motor, a pair of switches, a cam shaft for operating said switches, said cam shaft being rotatable between two terminal positions and having surfaces arranged to close one of said switches upon rotation from either terminal position and to open said one switch at either terminal position, said cam shaft also having surfaces arranged to operate the other of said switches intermediate its travel between said terminal positions, and means operated by the timer motor for operating said cam shaft in steps from one of its terminal positions to the other and back again at predetermined times.

16. In a time switch mechanism, the combination of, a timing motor, a drive shaft rotated by the timing motor, a cam shaft spaced from the drive shaft and substantially parallel with the drive shaft, said cam shaft being rotatable in opposite directions between two terminal positions, contact mechanism for controlling a pair of circuits and constructed to close either one circuit or the other or to break both of said circuits, means including cam surfaces and cam follower means cooperating with the cam surfaces for positioning said contact mechanism in accordance with the angle of rotation of said cam shaft, said cam surfaces and cam follower means being constructed and arranged to actuate the contact mechanism in a predetermined sequence for closing one or the other of said circuits and to open both of said circuits as the cam shaft is rotated from one of said terminal positions to the other, actuating cam means on the cam shaft and having a first engageable portion on one side of the shaft and a second engageable portion on the other side of the shaft, and a plurality of individually adjustable actuators mounted on the drive shaft for rotating the cam shaft to predetermined positions at predetermined times, one of said actuators engaging one of said engageable portions of the cam means for rotating the cam shaft in one direction and an other of said actuators engagin the other of said engageable portions of the cam'means for rotating the cam shaft in the opposite direction.

References Cited in the file of this patent Number UNITED STATES PATENTS Name Date Parker Apr. 25, 1916 Hart Apr. 9, 1929 Warren Apr. 14, 1931 Paschen et a1 Mar. 29, 1932 Porter Dec. 27, 1932 Greenwood et a1. Dec, 13, 1938 Brown Jan, 6, 1942 Geertz Mar. 3, 1942 Malone July 7, 1942 Potter Sept. 1, 1942 Gallagher July 25,1944 Urbas et a1 Oct. 10, 1944 Schroeder May 28, 1946 Flegal Nov. 4, 1947 Oakley Nov. 30, 1948 FOREIGN PATENTS Country Date Great Britain Jan. 16, 1932 France Apr. 14, 1931

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