US2139454A

US2139454A - Timer mechanism

Info

Publication number: US2139454A
Authority: US
Publication date: 1938-12-06
Anticipated expiration: 1955-12-06

Description

Dec. 6, 1938. E. M CABE TIMER MECHANISM Filed July 26, 1937 4 Sheets-Sheet 1 v INVENTOR. IRA E. M00965 ATTORNEY I. E. M CABE TIMER MECHANISM Filed July 26 Dec. 6, 1938.

, 1937 4 Sheets-Sheet 2 IN! 'ENTQR. IRA E. M 0486 By K 04 1 A T TOR NE Y Dec. 6, 1938. E, MCC BE 2,139,454

TIMER MECHANI SM Filed July 26, 1937 4 Sheets-Sheet 3 INVENTOR. lRA E. M CASE A TTORNEY Dec. 6, 1938. E. M CABE 2,139,454

TIMER MECHANISM Filed July 26, 1937 4 Sheets-Sheet 4 INVENTOR. lRA [.MGABE A TTORNE Y.

Patented Dec. 6, 1938 UNITED STATES PATENT OFFICE,

14 Claim.

This invention relates to improvements in timer mechanisms and more particularly to a timing device for use in connection with other devices for controlling the operation of an electriri cally operated and controlled coal stoking mechanism for domestic and industrial heating plants.

It is an object of this invention to so construct and connect this improved timer mechanism that it will operate the stoker to feed fuel at periodic intervals to prevent the tire from becoming extinguished when otherwise the stoker mechanism would be idle.

Other objects of this. invention include the construction of a mechanism operated by a synchronous electric motor to periodically operate means to closea circuit; to provide means toselect the number of times the circuit closing means may be operated each hour; to provide means to determine the duration of such closed circuit periods; to provide a relay in the timer actuated circuit closing means responsive to other control devices to close the said circuit independent of the timer mechanism; and to include in the timer mechanism means actuated by the said independent operation of the relay to delay the first timer operation of the relay following a completed independent operation thereof.

With these and others objects in view, referonce is made to the accompanying sheets of drawings, which illustrate an embodiment of this invention with the understanding that detaii changes may be made therein without departing from the scope thereof.

In the drawings:

Figure 1 is a view in front elevation of a preferred. form of this invention with the timer mechanism cover shown in sections.

Figure 2 is a view in diagram illustrating the electrical connections and a wiring diagram thereof.

Figure 3 is a fragmentary enlarged detail view in front elevation of the timer mechanism with the intermediate plate and other partsremoved.

Figure 4 is a view in side elevation of Figure 3, looking at the right side thereof, with parts re moved.

Figure 5 is a view similar to Figure 4 looking at the left side of Figure 3.

Figure 6 is a view similar to Figure 3, with parts removed, illustrating the means for determining the length oi on periods and showing the positions assumed by said parts in the on? position.

Figure 'l is a view similar to 56 Figure 6 showing the positions assumed by these parts at the initiation of the "on period.

Figure 8 is a view similar to Figure 6 showing the positions assumed preparatory to moving to the ofi position at the termination of the "on" period.

Figure 9 is a view similar to Figure 3, with parts removed, illustrating the means for selecting the number of on" periods per hour. 7

Figure 10 is a view similar to Figure 3, with parts removed and additional parts included, illustrating the means to prevent initiation or TM actuated by a self-starting synchronous electric motor adapted under certain conditions to operate an arm to close and open the motor switch during the periods when the room thermostat maintains the secondary circuit open. The entire mechanism is mounted upon a panel 6. with the timing mechanism TM mounted within a cylindrical cover 3 upon a base plate 8 spaced apart from the upper portion of the panel 6 by posts i and a relay of the general type as disclosed in this applicant's prior Patent No. 973,925 dated September 18. 1934. mounted upon a plate of insulating material 5 spaced apart by posts 6 from the panel I below and in line with the base plate 8.

The-movable secondary coil SC is mounted in a bracket B to oscillate about a pivot i upon the inner leg 8 of the rectangular core of the relay. The bracket B is provided upon the rear of the supporting plate 5 with an extension 9 which carries the motor switch support ill so that when the secondary coil SC rests upon the stationary primary coil PC the bracket B will be rotated about its pivot E to open the motor switch MS, preferably a mercury tube switch as shown. The bracket B, is also provided with a vertical extension il above the pivot l and a horizontal extension H to the left of the extension I i adapted to cooperate with the operating arm oi the timing mechanism under certain conditions to tilt the bracket about its pivot 1 to close the motor switch MS as shown in-Figures 1 and 10.

The timing mechanism includes a self-starting synchronous electric motor SM mounted upon a circular face plate I3. The synchronous motor SM operates atrain of gears G mounted between the face plate l3 and a similar intermediate plate 14 spaced apart therefrom by posts l5. The intermediate plate I4, is spaced apart from the base plate 3 by posts l3 as shown in Figure 4. The cover 2 is secured to the base plate by screws H. The train of gears G operate a pinion l3 upon the underside of the intermediate plate i4 meshing with a gear wheel is freely mounted upon one end of a driving shaft 23 having a bearing therefor in the intermediate plate I4, and a bearing 2| therefor in the base plate 3. The gear wheel l9, as shown in Figures 5 and '7, is held upon the shaft by means of a spring washer I9 and also mounts a flat U shaped spring 22 one end of which terminates in the form of a pawl adapted to engage the teeth upon a pinion 23 secured to the driving shaft 23 to impart movement thereto in a counter-clockwise direction as the gear 'is rotated in that direction. Screw threaded into the end of the shaft 23 opposite that mounting the gear wheel 13 is an operating stem terminating in a knurled head 23 to permit a manual rotation of the shaft to operate the mechanism, if desired. When manually operating the shaft in one direction no movement is imparted to the gear wheel I! as it is not fixed to the shaft and the tension of the spring washer i9 is such that the spring 22 will wipe over the pinion 23. If the operating head 23 is rotated in the opposite direction it unscrews itself from its threaded connection to the shaft so that manual operation of the mechanism is possible by rotation of the operating stem in only one direction.

The relay operaing arm of the timing mechanism is an off-set flat arm 24 depending from a U-shaped bracket the sides 25 of which are pivotally mounted upon studs 23 secured upon and intermediate the length of similar

shaped plates

21 and 28, on each side thereof. The arm 24 is oflset to pass through a cut out portion 29 of the base plate 3, Figure 3, and is then extended downwardly to engage behind the off-set ex tremity 30 of the horizontal extension l2 of the movable coil bracket B. The left extremities of the spaced apart

plates

21 and 23, are mounted on a stud 3| pivotally supported between the intermediate plate l4 and base plate 3, as shown in Figures 4 and 5.

Fixed upon the shaft 23, are two similar spaced

cam plates

32 and 33, each having two diametrically

opposite shoulders

34 and 35 with the shoulders of the plate 33 in a fixed relation in advance to the shoulders of the plate 32. The

cam plates

32 and 33 rotate between the sides 25 of the U-shaped bracket supporting the relay operating arm 24. The bracket supporting plate 21 adjacent the intermediate plate 14 mounts a stud 36 having a flattened surface extending in the path of the cam plate 32 and over which the cam plate rides. The stud 33, is resiliently held against the periphery of the cam plate 32 by a coil spring 31 connected to one of the posts i3 and to a post 3| connecting free ends of the

bracket supporting plates

21 and 23. The cam engaging stud 33 is arranged to the right of the bracket pivot stud 23 on the plate 21.

The

cam plates

32 and 33 rotate in a counterclockwise direction and as the shoulder 34 of the plate 32 rides over the stud 33 the spring 31 causes it to engage the ofl-set periphery of the plate therebelow allowing the spring 31 to impart an upward movement to the operating

arm supporting plates

21 and 23 about their pivot 3|. To utilize this action to impart a movement of the arm 24 to the left end of its oscillatory movement to tilt the motor switch MS to closed position by tilting the bracket B, the side 25 of the operating arm bracket adjacent the base plate 3 is extended beyond the other side 25 and mounts upon its inner side, a stud 33, to the right of the stud 33 on the opposite bracket supporting plate 21.

A lever 39 arranged upon the rear of the base plate 3 is provided with an enlarged end mounted for rotation upon the bearing 2| of the shaft 23 and at the other end with a bent-back portion 43 embracing an arcuate edge of the base plate 3 concentric with the shaft 23 terminating in a pointer 4| adapted to travel over a calibrated scale 42 as shown in Figures 1 and 3. The lever 33 mounts a stud 43 passing through an aperture 44 in the base plate 3 which pivotally mounts on its free end an actuating plate 45 adjacent the cam plate 33. The plate 45 mounts a stud 43 extending in the path of travel of said cam plate 33 having a flat surface to be wiped over by the periphery of said cam plate and is provided with an arcuate extension 41 curved about the under side of the shaft 23 and a horizontal extension 43 projecting over the operating shaft 23 terminating in a hook portion 43 adapted to engage the shaft 23 to limit the movement of the actuating plate 45 away from said shaft. When the stud 46 engages the outermost periphcry of the cam plate 33 it is held against movement toward the shaft 23. The fixed relationship of the cams are such that with the stud 43 placed in any position, as determined by the position of the lever 39, said stud will be in engagement with the outermost periphery of cam 33 before the stud 33 rides over the shoulder 34 of cam 32. The arcuate depending portion 41 of plate 45 extends beyond and to the left of the stud 33 upon the elongated side 25 of the operating arm bracket, as shown in Figures 6, '1 and 8.

The spring 31 causes the stud 33 to ride over the shoulder 34 of cam 32, as the cam is rotated to that point, and imparts an upward movement to the

support plates

21 and 23 but as the operating arm stud 33 is engaging the arcuate portion 41 of plate 45, which is held against movement inwardly at this time, the operating arm is caused to rotate around the stud 33 thus swinging the offset arm extension 24 to the left, as shown in Figure 7, which action tilts the bracket B. Figure 6 illustrates the position of the parts as the cam shoulder 34 approaches the stud 33 to impart the operation which causes the parts to assume the positions shown in Figure 7 and normally results in closing the motor switch MS. The motor switch remains closed until the shoulder 35 passes over the stud 43 whereupon the plate 45 is freed and the weight of the secondary coil swings the bracket B about its pivot to open the motor switch and at the same time swings the operating arm 24 to the right as the stud 33 is no longer held by the cated by the position of the pointer upon the Y scale 42.

If the train of gears operated by the synchronous motor are so arranged to impart one complete rotation of the operating shaft each hour, then the motor switch is closed, independently of the room thermostat T, each half hour as long as the room thermostat remains open, since the cam plate 32 is provided with diametrically opposed shoulders which allows the spring 31 to rotate the

bracket supporting plates

21 and 28 each time they wipe over the stud 36.

To limit the closing of the motor switch to one period for each complete cam revolution, if desired, a lock-out latch 50 is mounted upon a post pivotally supported between the base plate 3 and intermediate plate M to the right of the vertical center line and above

cam plates

32 and 33, as shown in Figures 5 and 9. This latch is curved about the left of the shaft 20 between

cam plates

32 and 33 and terminates in a notched end 52 so arranged that the weight of the latch normally causes the notched end 52 to engage an extended portion 3! of the stud 26 in the bracket supporting plate 21. As the shoulder34 of cam plate 32 passes over the stud 36 the latch 50 will hold it against the tension of the spring 31, as shown in Figure 9. The latch 50 is provided with an angularly inclined extension 53 upon its side adjacent the shaft 20 adapted to be engaged by a roller 54 mounted between the

cam plates

32 and 33 to move the end 52 out of engagement with the stud extension 31* as the roller 54 rides thereunder during each revolution of the cam plates so that the operating arm 23 is free to be actuated but once during each complete revolution of the shaft 20 or once an hour. In order to allow the operating arm to be actuated twice during each revolution of the shaft 20, or every half hour, the latch 50 is provided with an out-standing projection 55 adapted to be engaged by a stud 56 passing through an elongated slot 51 in the base plate 3 as shown in Figure 3, and carried on a lever 58 mounted at one end to rotate about the bearing 2| and having its free end 59 bent back upon itself to embrace the left edge of the plate 3, as shown in Figure 9, whereby upon an upward movement of the lever 59 the stud 56 will withdraw the latch to allow of two operations of the motor switch MS by the two cam shoulders 34 during each complete revolution of the shaft 20.

When it is desired to employ this invention for the control of coal stokers for the purpose of periodically causing the operation of the stoker, during periods when the stoker is not otherwise operated, for the purpose of maintaining the fire, it is desirable to prevent the operation of the stoker immediately following the termination of a stoker operation caused by other controls, such as a room thermostat. It is a purpose of this invention to prevent a timer operation of the stoker occurring for a minimum period, after a thermostat operation preferably fifteen minutes. This period may be longer, however, depending upon the position of the timer mechanism. When lever 58 is set for half hour operations the maximum delay period after the thermostat shuts off or opens the secondary circuit, may be forty-five minutes. When set for one hour operations, the maximum delay may be one hour and fifteen minutes. For this purpose, it is preferable to provide the timer mechanism with an additional lock-out latch 60 mounted upon a post 6| pivotally supported between the base plate 3 and intermediate plate M on the side of the vertical center line opposite the post 5|, as shown in Figure 10. The lock latch 83 is curved about the right of the shaft 20 and terminates in a notched extremity 52 adapted at times to engage and hold the stud extension 3'! in the same manner as the latch 50.

The latch 60 is provided with an outstanding hooked member 65 adapted normally to hold the latch 50 in its withdrawn position by engaging over a locking arm 66 extending from a plate 61. mounting intermediate its ends a post 68 pivotally supported between the base plate 3 and intermediate plate I4 and mounting at its other end a pin 89 passing through a slot provided therefor in the base plate 3, as shown in Figures 3 and 10. To prevent the closing of the motor switch by the timer mechanism immediately after the termination of a closed period of the motor switch actuated by the room thermostat T or other control, the free end of the vertical extension II of the bracket 13 carrying the movable secondary coil SC terminates in an angular surface H which when the relay is energized by the room thermostat T, or other control, upon the tilting of the bracket by the repulsion of the coil SC wipes under the pin 63 and lifts it to rotate the locking arm 33 from the position shown in Figure 3 to free the latch 60, as shown in Figure 10, to engage the stud extension 31*.

The side of the lever 60 towards the shaft 20 is also provided with an angular inclined extension 63 adapted to extend into the path of two diametrically arranged studs 53 upon the cam plate 33 adapted to ride over the extension 63 to withdraw the notched end 62 from engagement with the roller 31* twice during each complete revolution of the shaft 23. When the cams are operated one complete revolution each hour it is preferable to arrange the pins 64 to actuate the latch 60 fifteen minutes prior to the time when the cam shoulder 33 passes under the stud 36 which normally results in the closing of the motor switch MS. The purpose of the pins, it may be stated, is to check the position of the motor switch each fifteen minutes prior to each timer operation. If the motor switch is open when the pins 64 operate the latch 60 the mechanism is placed in condition to be operated to close the motor switch at the next timer operation unless the thermostat should cause a stoker operation in the meantime. If a thermostat operation has been completed before the engagement of pin 64 with the latch extension 53 the locking arm 66, freed when the relay opens the motor switch, assumes the full line position shown in Figure 10. When the arm 66 is in this position and the motor switch is open, the engagement of pin 64 with the extension 33 will raise the latch 60 permitting the locking arm to fall in under the latch hook member 65 whereby the notched extremity of the latch is removed from possible interference with the timer operations, as shown in Figure 3. However, if a thermostat operation is in effect when the pin 64 passes the extension 63 or is begun thereafter the arm 65 will free the latch 60 and the notched extremity will engage the stud extension 31 to prevent the next timer operation of the relay operating arm 23.

Figure 2 is a diagrammatical view of a practical application of this improved timing mechanism to the motor M of a coal stoker mechanism.,

The wire L is connected to the commercial line and carries the commercial current through the usual boiler or furnace safety control S to,the binding post 12 upon the panel I. The current then follows through the wire connected to the timing mechanism to energize the synchronous motor SM and from there to the binding post 13 and back through line L to the commercial line. The current also passes from binding post 12 through the winding of the primary coil PC and through binding post 15 to binding post 13 and thence by line L to the commercial source. The motor switch MS being in the open position the motor is not energized. The windings of the secondary coil SC are connected to the binding posts 16 and IT and to the room thermostat T. When the circuit is closed through the room thermostat to energize the secondary winding SC it is repelled from the stationary primary coil PC and tilts the motor switch MS to closed position. This establishes a circuit from binding post 12 through motor switch MS binding post I4 through the stoker motor M to binding post 15 and from there through binding post 18 to the return line L. It is seen from the above that whenever the house switch HS is closed to the commercial source, the primary winding PC is always in circuit and the synchronous motor of the timing mechanism TM is always in circuit and the motor circuit is closed whenever the room thermostat closes the secondary circuit or whenever the timing mechanism operates to tilt the bracket B.

What I claim is:

1. An electrically operated timer mechanism for opening and closing an electric switch periodically, including an electric motor, a pivoted switch operating arm, spring operated reciprocable means for mounting the pivot of the switch operating arm, cam means operated by the motor cooperating therewith to reciprocate periodically said reciprocable means against the tension of the spring and a predetermined time thereafter to free said means to the action of the spring to close the switch, said switch arm having a prolongation at one side of its pivot coacting with cam actuated means when engaged thereby to cause the arm to be rotated about its pivot to close the switch as the spring is freed to reciprocate its pivot.

2. The structure of claim 1 wherein means is included in the cam means to allow two normal operations of the switch arm during each complete rotation of the cam and wherein means is provided to prevent every other normal operation thereof.

3. The structure of claim 1 wherein means is provided to adjust the relation of the cam actuated means and the prolongation of the operating arm to determine the duration of the period the switch remains closed.

4. The structure of claim 1 in combination with means adapted to close and open the switch independent of the timer mechanism, and wherein the timer mechanism is provided with means operable after the switch has been closed and opened by said independent means to delay the next normal operation of the timer mechanism to close the switch.

5. An electrically operated timer mechanism for opening and closing an electric switch periodically, including an electric motor, cam actuating means operated by the motor, an oscillating switch operating arm, a bracket at one end thereof mounting a pivot and a stud spaced apart from the pivot, a support pivoted at one end mounting the bracket pivot intermediate its ends and engaging a spring at its other end to cause the bracket pivot to wipe over a cam of the actuating means, and a pivoted switch arm actuator coacting with a cam of the actuating means adapted to engage the stud on the arm bracket as the cam frees the support to the action of the spring to cause the lifting of the bracket pivot to oscillate the operating arm.

6. The structure of claim wherein said last mentioned cam at a predetermined interval thereafter releases the switch arm actuator.

7. The structure of claim 5 wherein said last mentioned cam at a predetermined interval thereafter releases the switch arm actuator and wherein the switch arm actuator mounts a stud to be wiped over by the coacting cam and wherein the pivot of the switch arm actuator is mounted for manual adjustment to alter the relation of the arm actuator stud to the cam release to predetermine the duration of the period the switch remains closed.

8. The structure of claim 5 wherein means is included in the cam means to allow two normal operations of the switch arm during each complete rotation of the cam and wherein means is provided to prevent every other normal operation thereof, including a pivoted latch provided with its free end normally engaging the bracket pivot to hold the'bracket support against the tension of the spring, said latch provided with a member coacting with a stud on the cam actuating means to move the end of the latch to free the pivot stud at each rotation of the cam to allow the lifting of the bracket support.'

9. The structure of claim 5 wherein the cam actuating means is formed to free the bracket support to respond to the action of the spring at each half revolution of the cam thereof, and a pivoted latch provided with its free end normally engaging the bracket pivot to hold the bracket support against the tension of the spring, said latch provided with a member coacting with a stud on the cam actuating means to move the end of the latch to free the pivot stud at each rotation 01 the cam, and wherein the latch is provided with manual means to withdraw the free end from engagement with the bracket pivot and hold it in the withdrawn position.

10. The structure of claim 5 in combination with means to close and open the switch'independent of the timer mechanism, a pivoted latch normally engaging the bracket pivot to hold the bracket support against the tension of the spring, a pivoted locking am having one end engaged normally with a lock member on the latch to hold the latch inoperative and operable by the independent closing of the switch to disengage the latch, and a member on the latch adapted to be engaged by means on a cam actuator intermediate the normal closing of the switch by said actuator to reengage the latch locking member with the locking arm after it has been freed by the opening of the switch.

11. A switching device for an electric circuit, a switch interposed in said circuit, operating means for opening and closing said switch, electrically controlled means for actuating the operating means, motor operated means for normally operating mechanical means for actuating the switch operating means to close the switch for periodic intervals, and means actuated by the electrically controlled means upon closing the switch within a predetermined time before the next normal switch closing operation of the mechanical means to render said mechanical means inoperative for the duration of that period,

12. The structure of claim 11, including locking means normally adapted to render the mechanical means inoperative, and means controlled by said motor operated means at selected intervals prior to normal switch closing periods to render the locking means ineflective.

13. The structure of claim 11, including locking means normally adapted to render the mechanical means inoperative, and means controlled by said motor operated means at selected intervals prior to normal switch closing periods to render the locking means inefiective, and manually operated means independent and exterior of said motor controlled means for permanently rendering the locking means ineffective until manually restored to operative position.

14. The structure of claim 11, wherein the mechanical means includes holding means actuated by the motor operated means to determine the duration the switch is closed by said mechanical means, and means to adjust said holding means exterior of the motor operated means.

IRA E. McCABE.