US3281548A

US3281548A - Interval timer

Info

Publication number: US3281548A
Application number: US366106A
Authority: US
Inventors: Walter J Sears; Polonsky Samuel
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1964-05-08
Filing date: 1964-05-08
Publication date: 1966-10-25
Anticipated expiration: 1983-10-25
Also published as: CH434128A; NL6505809A; DE1272426B; GB1076291A; CH607265A4

Description

i@ 5, fav@ 11 E 8 ,Zu/ 2, n Hf# 3 @d V /,ru Wk/edn f/M? /Ma m M f 5mm /WJ ST8 Mw EMM SEd Oct. 25, 1966 ldrive-out begins.

United States Patent G 3,281,548 ENTERVAL TIMER Walter J. Sears, Cupertino, Calif., .and Samuel Polonsky,

Medway, Mass., assignors to General Electric Company, a corporation of New Yori:

Filed May 8, 1964, Ser. No. 366,106 6 Claims. (Cl. 20G-38) This invention relates to an all-purpose interval timer and, more particularly, to a unique timer mechanism which enables a single knob to control manual on-oif operations in addition to timed-on and timed-off operations.

In addition to the conventional manual -on-oif switch operations, it is often desirable to be able to set a switch to either a timed-off or a timed-on position for a specified time after which the switch is automatically actuated to the opposite position. Timed-off is generally applied to the situation where the switch is set at an open circuit position and remains there for a specified time after which the switch is automatically actuated to a closed circuit position where it remains until manually reset. Timedon applies to the opposite sequence.

Conventional timers provide single-purpose timed-on or timed-off operations but the prior art has not heretofore produced a simple, all-purpose timer in which a single control knob may be used to set the timer for manual on-off operation in addition to automatically timed-on and timed-off operations.

It is therefore an object of this invention to provide an all-purpose interval timer having a plurality of timing operations.

Another object of this invention is to provide an interval timer wherein a single switch is used for manual-on, manual-off, timed-on, and timed-off operations.

A further object is to provide an interval timer which employs a simple but unique mechanism for rapidly actuating a single switch for both timed and manual operations.

Further objects and advantages will become apparent as the following description proceeds and the features of novelty are pointed out in the claims annexed to and forming part of this specification.

In carrying out this invention in one form thereof, a single switch is actuated by a cam and a cam follower or actuating rod. The cam and a driven member having internal and external gear sectors thereon are positioned in co-axial alignment on a set shaft. A control knob is attached to the set shaft for rotating the driven member and the cam for manual on-off operation and for engaging the external and internal gear sectors with a unidirectional driver pinion to effect 'timed on-oiir operation. When the control knob is set at the manual-on or manual-off positions, a spring engages a projection from the rotating mechanism and maintains the gear sectors out of engagement with the unidirectional driver pinion while the cam maintains the switch in a closed or an open circuit position, respectively. When the control knob is set to either the timed-on or the timed-off positions, the unidirectional driver pinion meshes with either the external gear sector or the internal gear sector on the driven member and During drive-out, the switch is maintained in an open or closed circuit position until the switch is actuated by the rotating cam to the opposite position, .at which time the gear sector is disengaged from the unidirectional driver pinion. Since engagement between the unidirectional driver pinion and the gear sector has been discontinued, the switch remains in either an open or closed circuit position until manually reset.

For a better understanding of the invention, reference is made to the accompanying drawing in which:

FIG. 1 is a front view of the timer with the base plate ICC removed showing the mechanism in manual-on position;

FIG. 2 is similar to FIG. 1 but shows the mechanism in timed-off position;

FIG. 3 is similar to FIGS. l and 2 but shows the mechanism in the timed-on position;

FIG. 4 is an end view of the timer showing the continuous driver motor and the conventional gearing used to drive the unidirectional driver pinion gear;

FIG. 5 is a perspective of the set shaft, cam, and the driven member.

Referring to FIGS. 1 and 2, the illustrated timer includes a switch 1 mounted between two plates 2a and 2b. The switch 1 includes a pair of spaced contacts 3a and 3b mounted on a contact-carrying arm 4. A movable contact 5 is disposed therebetween on a movable contact-carrying arm 6. Engagement between the movable contact 5 and either of the contacts 3a or 3b closes a circuit. The movable contact 5 is actuated by a cam follower 7. The movable contact-carrying arm 6 engages the cam follower 7 and yieldably forces the follower 7 into engagement with a rotatable cam 8. The follower may also be forced into engagement with the cam by a spring or other suitable means. The cam 8 is mounted on a set shaft 9 for rotation with a driven member 11 through a loose tongue and slot engagement 22, as illustrated in FIG. 5. Rotation of the set shaft 9 and the cam 8 actuates the switch between closed circuit and open circuit positions.

In order to achieve a variety of switching operations, it is desirable to be able to automatically and manually rotate the switch actuating mechanism in both directions. The set shaft 9 may be rotated by a knob 23 for manually actuating the switch 1 to an open or closed position. The set shaft 9 is also arranged for timed rotation by a continuous counterclockwise rotating driver pinion 10 for automatically actuating the switch to an open or closed circuit position after a predetermined time interval. Timed rotation of the set shaft 9 and the cam 8 is achieved by lselectively engaging the driver pinion 10 with the driven member 11 which is secured for rotation with the set shaft 9 as indicated in FIG. 5.

The driven member 11 has an external gear sector 12 for selective engagement with the driver pinion 10 on one side thereof to rotate the driven member 11 in a clockwise direction. A radially disposed arm 13 projects from the driven member 11 and extends beyond the radius of the external gear sector 12. A circumferential extension 14 from the radially extending arm 13 has a plurality of gear teeth comprising an internal gear sector 15 on the radially inwardly disposed surface thereof. The internal gear sector 15 `selectively engages the opposite side of the driver pinion 10 and rotates the driven member 11 in a counterclockwise direction. Since the driver pinion 10 is continuously rotated in a counterclockwise direction by a motor 20 and a gear train 21 as'shown in FIG. 4, suitable clutch means (not shown) are employed in the gear train 21 to allow for manual engagement of the gear sectors with the driver pinion during which time the driver pinion is forced to rotate opposite to its normal continuous direction of rotation.

AThe external gear sector 12 and the internal gear sector 15 are angularly displaced on the driven member 11 with a gap 24 therebetween. The driver pinion 10 rotates the driven member 11 by engaging the gear sectors 12 and 1S. The driver pinion 10 tends to drive the gear sectors out of engagement therewith, thereby positioning the gap 24 adjacent the driver pinion 10. By employing a driven member having both external and internal gear sectors selectively engageable with a unidirectional driver pinion, it is possible to achieve bidirectional rotation which, when applied to a cam member, may be used to actuate a switch to a variety of timed opera-tions.

The variety of operations contemplated by this invention include timed-on, timed-off, manual-on, and manualolf. To actuate the switch 1 during the four above-mentioned operations, the cam member 8 is employed. The driven member 11 operates to rotate the cam lt! and to actuate the switch through the cam'follower 7. The cam 8 has a plurality of major earn surfaces, namely, a timedopen circuit position surface 8a, a closed circuit position surface 8b, a timed-closed circuit position surface 8c, and an lopen circuit position surface 8d. The major cam surfaces have transition cam surfaces 25 therebetween. Actuation occurs when the cam follower engages the transition surfaces 25 between the major cam surfaces. If the cam were to move at its normally slow rate while the follower engages the transition surfaces 25, the switch would be actuated slowly and arcing might occur. To Iaccelerate switch actuation and to obviate the necessity of using a snap-action switch, the cam 8 is floatingly mounted on t-he set shaft 9 to enable relative rotation between the cam and set shaft. The loose tongue and slot engagement 22 between the cam 8 and the driven member 11 permits a small degree of relative rotation between the cam and driven member. The loose engagement enables the cam 8 to be rapidly rotated relative to the driven member 11 through a small angle by the cam follower 7 when the follower 7 engages the transition surfaces 25. The follower 7 is yieldably Iforced -against the cam 3 by the movable contact carrying arm 6 to assist the rapid rotation of the cam 8 during switch actuation.

The set .shaft may be lmanually setto maintain the switch in either a manual open or a manual closed circuit posh tion. A spring an-d ldetent mechanism is employed to maintain the set shaft in either manual position. The mechanism includes a projection 17 from the Idriven memA ber 11 having an open circuit detent 18 and a closed circuit detent `19 disposed therein. A spring 16 is arranged between the plates 2a and 2b and projects into the path of rotation of the projection 17. The spring 16 and provjection `17 are arranged so that either detent may be selectively engaged with the spring to releasably secure the set shaft from rotation.

In order to clearly appreciate the physical relationship between the four surfaces of the cam 8, the gear sectors and the gap there-between on the driven member 11, and the driver pinion during the various operations, each operation will be discussed separately.

Timed-open circuit operation F or timed-open circuit operation, the driven member 11 is manually rotated clockwise by the con-trol knob 23 until the internal gear sector is rotated into meshed engagement with the driver pinion 10. After the manual setting force has been released, drive-out begins for the timed-open circuit operation and the driver pinion 10 rotates the driven member 11 in a counterclockwise direction. The time during which the driven member 11 is rotated `depends upon the proportion of the internal gear sector 15 through which the driver pinion 10 must -advance before the gap 24 between the gear sectors is positioned f adjacent the -driver pinion 10 and meshed engagement is terminated. The timed-open circuit position surface 8a of the cam 8 is angularly arranged .relative to the driven member 11 so that the cam follower 7 engages the cam `surface 8a only when the driver pinion 10 is in meshed engagement with the internal gear sector 15 as indicated in FIG. 2. While the cam follower 7 engages the cam surface 8a, the movable contact 5 is maintained out of engagement with the contacts 3a and 3b and the switch is maintained in an open circuit position.

The closed circui-t position surface 8b of the cam 8 is disposed adjacent the cam surface Sa and angularly arranged relative to the driven member 11 so that the cam follower 7 begins to contact the cam surface 8b at the end of the timed-open circuit drive-out, at which time the switch 1 is actuated to a closed circuit position. Actuation occurs when the cam follower 7 engages the transition surface 25 between the cam surfaces 8a and 8b. The force exerted by the follower 7 on the transition surface 25 rapidly rotates the cam 8 through the loose tongue and slot e-ngagement 22. The rapid cam rotation accelerates switch actuation and avoids the necessity of using a snap-action switch. At the end of timed-open circuit drive-out, the driver pinion 10 has rotated the driven member 11 so that the gap 24 between the

gear sectors

12 and 15 is positioned adjacent the driver pinion 10, thus causingr the driven member 11 and the cam 3 to stop rotating. Since rotation of the cam has stopped, the switch is maintained in a closed circuit position until manually reset.

Timed-closed circuit operation IFor timed-closed circuit operation t-he driven member 11 is manually rotated counterclockwise by the control knob 23 until the external gear sector 12 is rotated into meshed engagement with the driver pinion 10. After the manu-al setting force has` been released, drive-out begins for the timed-closed circuit operation and the driver pinion 10` rotates the driven member 11 in a clockwise direction. The time during which the driven member 11 is rotated depends upon the proportion of the external gear sector 12 through which the driver pinion 10 must advance before the gap 24 between the gear sectors is positioned adjacent the driver pinion 10 and the meshed engagement is terminated. The timed-closed circuit position surface 8c of the cam S is angularly arranged relative -to the driven member 11 so that the cam follower 7 engages the cam surface 8c only when the driver pinion 10 is in meshed engagement with the external gear sect/or 12 as illustrated in FIG. 3.

The op-en circuit position surface 8d of the cam 8` is angularly arranged relative to the driven member 11 so -that the cam surface 8d is rotated into engagement with the cam follower '7 at the end of timed-closed circuit drive-out, a-t which time the cam `surface Sd actuates the switch to an open circuit position. Switch actuation from the timed-closed to open cir-cuit position is -accelerated by the rapid cam rotation relative to the driven member by means of the loose tongue and slot engagement 22. At the end of timed-closed circuit `drive-out, the gap 24 between the gear sectors 12 and 1S is positioned adjacent the driver pinion 10 and the driven member 11 stops rotating. Since the driver pinion 10 is no longer meshed with the drive-n member 11, the switch is maintained in an open circuit position until manually reset.

Manual closed-circuit operation At the end of the timed-open circuit operation, the cam surface 8b is in engagement with the cam follower 7 and rotation of the actuating mechanism has stopped. The switch is in a closed circuit position and the gap 24 between the

gear sectors

12 and 15 is positioned adjacent the driver pinion 10. The closed-circuit position surface 8b of the cam 8 is wide enough to allow for additional manual rotation of the actuating mechanism without changing the switch position. Also, the gap 24 is angularly arranged relative to the driver pinion 10 and the adjacent cam surfaces 8b and 8d to allow for manual rotation of the cam surface 8b or cam surface 8d into contact with the cam follower 7 without engaging the gear sectors and the driver pinion.

Manual-closed circuit operation, as illustrated in FIG. 1, is achieved manually by rotating the set shaft counterclockwise through a small angle after the end of the timed-open circuit drive-out sequence. The additional angular rotation causes the closed circuit detent 18 in the projection 17 to engage the spring 16 supported between the base plates 2a and 2b.

The cam follower 7 is maintained in engagement with the closed circuit position surface 8b during the additional angular rotation necessary for engaging the spring in setting the timer at the manual-closed circuit position.

The force of the spring 16 in the closed circuit detent 19 'releasably secures the actuating mechanism from further Manual open-circuit operation At the end of the timed-closed circuit operation, the

cam surface 8d is in engagement with the cam follower 7. The switch is in an open-circuit position and the gap 24 between the gear ysectors 12 and 15 is positioned adjacent -the driver pinion 10. Additional angular rotation in a clockwise direction causes the projection 17 on the driven member 11 to engage the spring 16 within the open circuit detent 1S. The cam follower 7 is maintained in engagement with the open circuit position surface 8d during the additional angular -rotation necessary for engaging the spring in setting the timer at the manual open circuit position. The force of the spring 16 in the open circuit detent 18 releasably secures the set shaft from further rotation except by subsequent manual rotation.

From the aforegoing discussion it will be apparent that the timer mechanism of this invention provides for simple, single knob operation of a variety of timed and manual switch operations.

While a specific embodiment of this invention has been shown and described, it is not intended that the invention be limited to the particular structure shown and described and it is intended by the appended claims to cover all modifications within the spirit and scope of this invention.

What is claimed is:

1. An interval -timer mechanism comprising:

(a) a unidirectional driver pinion;

(b) means driving said driver pinion;

(c) a bidirectional driven member having first and second gear sectors;

(d) said rst gear sector engaging said driver pinion on one side thereof to effect rotation of said driven member by said driver pinion in one direction;

(e) said second gear sector engaging said driver pinion on the opposite side thereof to effect rotation of said driven member by said driver pinion in the opposite direction, and

(f) a switch, means in operative engagement with and actuated by said driven member after a predetermined movement in one direction for closing said switch and after a predetermined movement in the `opposite direction for opening said switch.

2. An interval timer as recited in claim 1 wherein said driven member comprises said external gear sector having external gear teeth thereon, a radially disposed arm angularly displaced from said external gear sector and extending to a greater radius than said external gear teeth, said arm having a circumferential extension therefrom with a plurality of gear teeth on the internal face thereof comprising said internal gear sector, and said external gear sector being angularly spaced from said internal gear sector.

3. An interval timer as recited in claim 1 wherein said means -for opening and closing said switch comprises a cam actuated by said driven member, said cam comprising:

(a) a rst cam surface maintaining said switch open when said driver pinion engages said internal gear sector;

(b) a second cam surface maintaining said switch closed when said internal gear sector is driven out of engagement with said driver pinion;

(c) a third cam surface maintaining said switch closed when said driver pinion engages said external gear sector, and v (d) a fourth cam surface maintaining said switch open when said external gear sector is driven out of engagement with said driver pinion.

4. An interval timer as recited in claim 3 including:

(a) a set shaft, said driven member being secured to said set shaft for rotation with said set shaft and said cam being floatingly mounted on said set shaft adjacent said driven member,

(b) a loose tongue and slot engagement between said cam and said driven member for enabling said driven member to rotate said cam,

(c) a cam follower engaging said cam for actuating said switch, said cam follower being biased against said cam to rapidly rotate said cam through said loose tongue and slot engagement when said follower engages said cam between said first and second cam surfaces and said third and fourth cam surfaces, whereby said switch is rapidly actuated from an open circuit position to a closed circuit position `and from a closed circuit position to an open circuit position.

5. An interval timer comprising:

(a) a unidirectional driver pinion;

(b) means for driving said driver pinion;

(c) a bidirectional driven member having an internal gear sector and an external gear sector, said internal gear sector being angularly spaced from said external gear sector;

( d) said internal gear sector engaging said driver pinion on one side thereof to effect rotation of said driven member by said driver pinion in one direction, and said external gear sector engaging said driver pinion the opposite side thereof to effect rotation of said driven member by said driver pinion in the opposite direction;

(e) a switch, switch actuation means in operative engagement with and actuated by said driven member after a predetermined movement in one direction for closing said switch and after a predetermined movement in the opposite direction for opening said switch;

(f) a radially projecting arm on said driven member having a first and a second detent;

(g) spring means mounted between a pair of plates on said timer for engaging said first and second detents;

(h) manual means for rotating said driven member and said arm for positioning said first and said second detents into and out of engagement with said spring means;

(i) said switch actuation means comprising cam means, said cam means being angularly arranged with said arm and said detents to maintain said switch open when said spring means engages said rst detent and to maintain said switch closed when said spring means engages said second detent;

(j) said driven member being angularly arranged with said arm and said cam means to maintain said gear sectors out of engagement with said driver pinion when said spring means engages said first and said second detents.

6. An interval 4timer comprising:

(a) a driver pinion;

(b) :unidirectional means for driving said driver pinion;

(c) a bidirectional driven member having external and internal gear sectors for engagement with said driver pinion, said external gear sector engaging said driver pinion on one side thereof for rotating said driven member in one direction and said internal gear sector engaging said driver pinion on the opposite side thereof for rotating said driven member in the opposite direction;

(d) `a switch, a cam mounted for rotation with said driven member for opening and closing said switch;

(e) said cam maintaining said switch closed when said external gear sector engages said driver pinion and said cam maintaining said switch open when said internal gear sector engages said driver pinion;

(f) said cam actuating said switch from a closed to an open position when said external gear sector is driven out of engagement with said driver pinion;

(g) said cam actuating said switch from an open t0 a closed position when said internal gear sector is driven out of engagement with said driver pinion;

(h) manual means for 'rotating said cam for selectively opening and closing said switch When said driver pinion is not in engagement with said gear sectors, and for selectively rotating said gear sectors into engagement with said driver pinion.

. References Cited by theEXaminer UNITED STATES PATENTS Morrison 200-38 X Morrison 200-38 Swayze 200--38 Holstein 200-35 Everard 200-38 Harris 200--38 X l0 BERNARD A. GILHEANY, Primary Examiner.

H. M. FLECK, Assistant Examiner.

Claims

1. AN INTERVAL TIMER MECHANISM COMPRISING: (A) A UNIDIRECTIONAL DRIVER PINION; (B) MEANS DRIVING SAID DRIVER PINION; (C) A BIDIRECTIONAL DRIVEN MEMBER HAVING FIRST AND SECOND GEAR SECTORS; (D) SAID FIRST GEAR SECTOR ENGAGING SAID DRIVER PINION ON ONE SIDE THEREOF TO EFFECT ROTATION OF SAID DRIVEN MEMBER BY SAID DRIVEN PINION IN ONE DIRECTION; (E) SAID SECOND GEAR SECTOR ENGAGING SAID DRIVEN PINION ON THE OPPOSITE SIDE THEREOF TO EFFECT ROTATION OF SAID DRIVE MEMBER BY SAID DRIVER PINION IN THE OPPOSITE DIRECTION, AND (F) A SWITCH, MEANS IN OPERATIVE ENGAGEMENT WITH AND ACTUATED BY SAID DRIVEN MEMBER AFTER A PREDETERMINED MOVEMENT IN ONE DIRECTION FOR CLOSING SAID SWITCH AND AFTER A PREDETERMINED MOVEMENT IN THE OPPOSITE DIRECTION FOR OPENING SAID SWITCH.