US2203556A - Timer - Google Patents

Description

June 4, 1940. H. E. WARREN TIMER Filed Aug. 4, 1959 Inventor Henry )5. Warren, b

His Attorney Patented June 4, 1940 I UNITED STATES PATENT OFFICE TIMER Application August 4, 1939. Serial No. 288,360

Claims.

My invention relates to timers and particularly a timer for operating a switch or the like at a predetermined adjustable time interval following an operation which sets the timer into timing op- 5 eration. v It is the object of my invention to provide a reliable low cost timer of this type which is adapted for general application.

The features of my invention which are believed to be novel and patentable will be pointed out in the claims appended hereto. For a better understanding ofmy invention reference is made in the following description to the accompanying drawing in which Fig. 1 is a perspective front view of a preferred embodiment of my invention, and Fig. 2 is a partially sectional side of the central part of the apparatus as seen from the right of Fig. 1. 4

Referring to Fig. 1, 2i represents a timer motor.

This motor may be a synchronous electric motor 20 which operates continuously when the device is being used. Motor 2| drives the gear 32 which is part of a friction clutch. The other parts of the clutch consists of a spring 3 secured to a shaft 4 on which gear 32 is rotatable. Shaft 25 4 extends forward through a front plate I1, and has'secured to it, at the rear of the plate, a

. latch member 1 and, to the front of the plate, a, holding finger i co-operating with a stop 6. Motor 2| tends to drive shaft 4 in a counter- 30 clockwise'direction but when the holding finger I rests against stop t shaft 4 is held from rotation and the clutch 32-3 slips. A timing operation is initiated by removing stop 6 from holding position in any suitable way. In the illus- 85 tration, stop 6 extends through a slot 33 in the front plate I1 and is pivoted at 34 to the rear of the plate. Stop 8 is normally held up against the upper end of slot 33 by a spring 24 and when in this position extends into the path of rotation 40 offl'nger i and prevents rotation of shaft 4 and the attached finger I past this point. Finger 5 may be released by simply depressing stop 6 .momentarily either manually or otherwise.

Rotatively mounted on shaft 4 to the rear of 45 latch l is a disk 9. This disk is urged to retate in a clockwise direction by a spring I i which is always under more or less tension. Spring ll may be coiled about shaft 4 between a pin II in disk I and an abutment 2!. Disk 9 has a 50 switch operating member l2 projecting radially from its forward face, which member serves to move a resilient spring blade I: of a switch.

One stationary contact of this switch is represented by screw II which is adiustably threaded as through a suitable terminal block. switch blade i3 is biased to engage with contact It. An abutment 22 serves to limit the opening movement of switch blade I: with respect to contact I6 and the rotation of member l2 and disk 9 in a clockwise direction. The abutment 22 may also 5 serve as another stationary contact of the switch. The minimum tension of spring ii is sufficient to definitely move and hold the resilient switch blade I! away from contact l6 against abutment 22. 10

Pivoted to a post 23 extending from the front 1 face of disk 9 is a latch arm 8 notched on its lower edge to cci-operate with the latch member 'l on shaft 4. The free end of latch arm 8 extends to the left and may be lifted from engagement with latch member 1 by a pin I4 which pin extends from the rear of an adjustable dial plate I5. Dial plate I5 is rotatable about the same axis as shaft 4 and may have gear teeth in its periphery so as to be rotated by a. gear I8 on a shaft 35. Shaft 35 extends forward through the front plate where it is provided with a thumb piece 38 for convenience in adjusting the dial l6 and hence the position of releasing pin l4.

The front plate ll has-an opening at 31 through which a portion of the graduations on dial l5 may be seen and a setting index 20 is provided on the front plate adjacent the opening for the purpose of setting any desired time graduation on disk I! opposite thereto. Friction serves to hold said gear and dial ii to the position to which they have been adjusted.

The operation of this device will be apparent from the following. The parts are shown in the idle position with finger 5 against stop 6 holding shaft 4 and catch 1 stationary. This may be referred to as the zero position of shaft 4. Spring II is under sufiicient tension to hold disk 9 with its switch operating finger i2 in the initial position shown holding resilient switch contact'li 40 against abutment 22. In such positions of shaft 4 and disk 0, the notch on the lower edge of latch arm I is in engagement with the stepped surface of catch 1 secured on shaft 4 such that as soon as shaft 4 starts to turn in a counterclockwise direction, disk 9 will also be rotated counter-clockwise through the driving connection of the latch parts I and I and immediately allow switch contact I! to close on contact i6. If the device were adjusted for a zero timing interval, pin N on dial I! would be against the lower edge of catch arm 4 and partially raising it so that it would release catch 1 by a slightcounter-clockwise rotation of shaft 4. In such a case the switch contacts It-ii would remain open upon rotation of shaft 4. For such zero time interval adjustment the zero graduation of dial l5 should be opposite reference mark Ml.

units may be minutes, seconds, fractions of asecond, etc., depending upon how fast the motor M is arranged to drive shaft 4. For purposes of illustration, let it be assumed that the time units marked on dial l5 represent seconds. Hence the device is now adjusted for a timing interval of 2 seconds. Motor 2!! is assumed to be in operation and hence the friction clutch at 3 slips because shaft 6 is held from rotation by stop 6. A timing interval operation is now started by simply momentarily depressing stop 6, thereby releasing arm 5 and shaft 4 which immediately start to rotate in a counter-clockwise direction at a constant speed. Latch-member I which is secured to shaft 4 also rotates and carries with it latch arm 8 and disk 9. Switch operating finger I2 moves away from contact it and it closes against contact 66. A very slight rotation of shaft 4 is of course required before the switch will close but this is a constant amount for all settings and is taken into consideration in the graduation of the zero of dial id. The torque on shaft 4 necessary to drive shaft 4 against the tension of spring i ii is not sufficient to slip clutch 3, 32. Hence the switch is closed and disk 9 rotates counter-clockwise with shaft d. In two seconds, in the example given, catch lever 23 is rotated against pin iii and is raised to release it from catch member 1. Counter-clockwise rotation of disk 9 also further tensions spring ii. Spring it then returns disk 9 and with it pin 62 to the initial position shown to open the switch l3l6. Shaft t and the parts 5 and i carried thereby continue to rotate until they have completed one revolution when stopped by stop 6, and the device is now ready for another timing operation. If a different switching period is desired, the dial it is readjusted to a new position by turning thumb piece 36 until the desired time period appears opposite indicator Zil.

As shown in Fig. 2 the-latch arm 3 at end of pin 84 move in a plane, parallel to d which is to the front of the switch structur hence these parts are not interfered with by the switch structure and can rotate past the same. Switch operating finger i?! can rotate nearly 360 degrees until it comes against the rear of abutment 22. Thus nearly the entire 360 degree periphery of dial it is available for time setting purposes. The holding surfaces of catch 71 and latch arm 8 are cut at such an angle that there is no binding or lmking action which would prevent their release When arm 8 is being released by its movement against releasing pin i i and; the pressure against pin Mis not sufficient to rotate dial I5 nor is the added torque required suflicient to slip the clutch at 3. I

Preferably the pin'lll to which the spring it is attached or another pin extends to the front of disk 9 outside of' catch arm 8 to preventarm 8 from swinging too far out and getting out of place when the time adjustments'are such that this arm' is released when arm Bis beneath shaft 4.

" rear contact 13 and abutment 22 used as a contact I may be included in another circuit to provide a predetermined adjustable time opening of the circuit. Or, the switch may be used as a time controlled single pole, double throw switch. In

case a continuous on and off time cycle is desired, the stop 6 may be withdrawn continuously by simply unhooking spring 24.

When the switch operating pin l2 returns to the switch operating position at the end of a timing operation it does so with some force due to the tension of spring H. In order to prevent bouncing of pin l2 and chattering action of the contacts at this time I prefer to provide a fly wheel or inertia element 38 on disk 9 as best shown in Fig. 2. The inertia element 38 may be simply a disk in frictional engagement with disk 9, the two being urged together by a spring 39. When the disk 9 is returned to azero position at the end of a timing operation and is suddenly stopped by pin i2 coming against its stop, inertia part 38 continues to rotate by a slight amount and the friction force between it and disk 9 .is in a direction to oppose any reverse bouncing rotation of disk 9 at this time. This frictional force is made sufficient to'prevent any bouncing action when the disk Q returns to a zero position.

The gears shown between motor 29 and the gear are merely representative. Any desired gear ratio may be used and such gears may readily changed to obtain a different timing rate of shaft i. ing of a timing operation, the stop 6 may be withdrawn by a solenoid lii (see Fig. 2). The presence of such solenoid does not interfere with manual operation of stop What I ciaim as new and desire to secure by Letters Patent of the United States is:

1?. A. timer comprising a timer motor, a shaft, in friction. clutch through which said ay be driven. in one direction by said motor, a "ch-operating member rotatively mounted on in a direction opposite to the direction of rotation of said shaft, a stop for limiting such rotation of the switch-operating member, latch means having co-operating parts secured to said shaft and switch-operating member which, when engaged and the shaft is rotating, causes rotation of said switch-operating member with said shaft, means for releasing said catch parts after said switch-operating member has been rotated a predetermined adjustable part of a rotation from its stop, and a switch operated by said switch-operating member when it returns toits stop.

2. A timer comprising a timer'mot'or, a'shaft;

a slip friction clutch through which said'shaft maybe driven in one direction by said motor; a

For remote or automatic startt, a spring urging said operating member is rotated away from and switch-operating member rotatively mounted on saidshaf't, a spring for urging said switch-oper ating member to rotate ina direction opposite 7i.

tension of said spring, removable stop means for' to the direction of rotation of said shaft, a stop for limiting such rotation of the switch-operating member, latch means having co-operating parts on said shaft and switch-operating member which, when engaged in driving relation and the shaft is rotating,causes rotation of the switchoperating member away from its stop against the stopping the rotation of said shaft in a position where the latch part thereon will engage in driving relation with the latch part on the switchoperating member when the latter is in its. stop limiting rotary position, means for releasing said latch parts, said means being adjustable so as to release said latch parts at different desired rotary positions of the switch-operating member, and a switch operated by said switch-operating member when it moves away from and returns to its stop.

3. A timer comprising a constant speed electric motor, a shaft, a slip friction clutch through which said shaft may be driven by said motor in one direction, a switch-operating member mounted for rotation about said shaft, a spring for urging said operating member to rotate in a direction opposite to that in which the shaft is driven by said motor, a stop for limiting such rotation of the operating member, a removable stop for stopping rotation of said shaft in one rotary position, means having cooperating parts on said shaft and operating member for establishing a driving connection between said shaft and operating member when both are in their stopping positions, time graduated adjustable means for interrupting said driving connection after the operating member has been driven a predetermined adjustable part of a revolution away from its stop by said shaft, a switch operated by the switch operating member as it moves away from and returns against its stop, and an inertia fly wheel frictionally coupled with said rotary switch-operating member for preventing rebound of the latter when it is returned against its stop by said spring.

4. A timer comprising a rotary switch actuating member, a stop therefor, a spring biasing said actuating member to an initial rotary position against said stop, a switch biased to one position but held in another position by said actuating member when the latter is in its initial position,

' a shaft on the axis of rotation of the switch actuating member, means for driving said shaft at constant speed, means establishing a driving connection between said shaft and the switch actuating member when said parts are in one rotary position with respect to each other, such that the switch actuating member isdriven away from its Y stop, said spring is tensioned and said switch is allowed tomove to the position to which it is biased, means for interrupting said driving connection to permit the return of said switch actuating member to its initial position, said interrupting means being adjustable to vary the distance less than a complete revolution traveled by the actuating member from its initial. position when such interruption occurs, and means for starting and stopping said shaft when it is at such rotary position as'to establish driving connection with said actuating member when the latter is in its initial rotary position.

5. A timer comprising a drive shaft, a switch actuating member and a time graduated setting dial mounted for independent rotation on the same axis, a timer motor, a slip friction clutch through which said shaft is driven by said motor in a given direction, stop means for stopping the rotation of said shaft when it arrives at a zero rotary position, said stop means being removable from stopping position at will, a spring tensioned to rotate said switch actuating member in the opposite direction, a switch having a resilient movable contact member biasing the switch to closed position but held in an open position by said switch actuating member when in an initial position to which it will normally be rotated by said spring, a latch having co-operating parts on said shaft and switch actuating member through which the latter may be driven by said shaft against the tension of said spring to allow said switch to close, means on said time graduated dial for releasing said latch to allow the switch actuating member to return to its initial position, said dial being adjustable to cause such release at different rotary positions of said switch actuating member with respect to its initial position, said dial indicating the time the switch is closed during a timing operation, said latch parts being positioned to engage when said shaft is in its zero position and said switch actuating member is in its initial position.

Images