US3564310A - Motor driven interval timing mechanism - Google Patents

Abstract

An electric motor driven mutilated timing gear is manually set in either direction away from an ''''off'''' position. A signal device is held in ''''nonsignal'''' condition by a face of the gear. The gear is rotated towards the off position by a timing mechanism. When the gear reaches a signal position it releases the signal device and is decoupled from the timing mechanism.

Description

United States Patent Thomas G. Willis Raleigh, N.C.

App], No. 774,940

Filed Nov. 12, 1968 Patented Feb. 16, 1971 Assignee Westinghouse Electric Corporation Pittsburgh, Pa.

a corporation of Pennsylvania Inventor MOTOR DRIVEN INTERVAL TIMING MECHANISM 6 Claims, 6 Drawing Figs.

US. Cl. 310/83; 310/15; 200/38 Int. Cl H02h 7/06 Field of Search 200/38, 38(C),

[56] References Cited UNITED STATES PATENTS 3,327,073 6/1967 Bement et al 200/38 3,434,027 3/1969 Cummings ZOO/38X 3,440,370 4/1969 Willis et al 200/38 Primary Examiner-D. F. Duggan Attorneys-A. T. Stratton and C. L. Freedman ABSTRACT: An electric motor driven mutilated timing gear is manually set in either direction away from an off position. A signal device is held in nonsignal" condition by a face of the gear. The gear is rotated towards the off position by a timing mechanism. When the gear reaches a signal position it releases the signal device and is decoupled from the timing mechanism.

CROSS-REFERENCES TO RELATED APPLICATIONS Certain subject matter herein shown is disclosed and claimed in the copending patent application of myself and E. C. Knecht, Ser. No. 612,705, filed Jan. 30, 1967, now U.S. Pat. No. 3,440,370 and assigned to the same assignee.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to an interval timing mechanism and it has particular relation to an interval timing mechanism which may be manually set in either direction away from an off position.

2. Description of the Prior Art I In a conventional mechanism for measuring a selected time interval, a gear has an off position. The gear is manually moved away from the off position to an extent corresponding to the duration of the interval to be measured. Timing mechanism is coupled to the gear for the purpose of returning the gear towards the off position at a controlled rate. When the gear reaches a signal" or buzz" position, a signal is sounded to indicate the end of the intervaLThe gear then is manually returned to its off position.

One type of prior art mechanism permits movement ofthe gear in only one direction away from the ofi' position. An example is shown in U.S. Pat No. 2,993,099 which issued July 18, 1961.

In another type of prior art mechanism the gear may be moved in either direction away from the off position. An example is found in US. Pat. No. 2,886,106 which issued May 12, 1959. As shown in FIG. 18 of this patent a pin 304 is received in a notch 313 in the off position.

SUMMARY OF THE INVENTION In accordance with the invention an interval timing mechanism includes a mutilated gear which has an off position, a signal or buzz position and any one of a number of positions which may be manually selected to measure a desired interval. A signal device has a control member biased against one face of the gear to hold the signal device in nonsignaling condition. When the gear reaches its signal position a recess in the gear clears the control member to permit production of a signal. The gear is manually movable to an off position established by the configurations of the gear and control member, and may be manually moved from the off position in either direction.

It is therefore an object of the invention to provide an interval timing mechanism which has timing, signal and off positions determined by the relationship between a gear and a control member coacting with the, gear.

It is another object of the invention to provide a mechanism as defined in the preceding paragraph wherein the gear has a cam surface and the control member constitutes a cam follower for the cam surface.

BRIEF DESCRIPTION OF THE DRAWING Other objects of the invention will be apparent from the following description taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a view in cross section with parts broken away of an interval'timing mechanism embodying the invention;

FIG. 2 is a view in perspective with parts broken away of the mechanism of FIG. I;

FIG. 3 is a view in front elevation of a mutilated gear, with a follower associated therewith;

FIG. 4 is a view taken on the line IV-IV of FIG. 3; and

FIGS. 5 and 6 are views similar to FIG. 4 but representing time displaced positions of the illustrated parts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a timing mechanism including an hour hand H and a minute hand M which are mounted for rotation about a common axis A and which are associated with a dial (not shown) in a conventional manner to indicate the time of the day. An interval pointer I is also mounted for rotation about the same axis for selecting an interval of time which is to be measured. The interval pointer may coact with a dial (not shown) which is calibrated to indicate the angular position of the pointer about its axis in terms of the time intervals represented by various pointer positions up to the maximum permitted by the drive. Although the drive may be arranged for different maximum intervals, a maximum interval of 60 minutes is frequently employed. v

Spaced supporting plates 1 and 3 are provided for the mechanism associated with the hands H and M and the pointer I. The hand H has a hub which is a press fit on a tubular sleeve H1. The sleeve H1 is mounted for rotation about the axis A in a bushing B which is secured to the plate 1.

The minute hand M has a hub which is a press fit on a sleeve M1 which is mounted within the sleeve H1 for rotation about the axis A relative to the sleeve H1. The sleeve Ml carries a pinion M2 which is coupled through gearing G to a gear H2 secured to the sleeve H1 for the purposeof revolving the hour hand H once for each l2revolutions of the minute hand M.

The pinion M2 has mounted thereon for independent rotation about the same axis a gear 5 which is biased against the pinion by a spring 8 to form a slip clutch which transmits sufficient torque to permit operation of the hands H and M by the motor 7. However, when the hands are to be manually set to a different time indication, the slip clutch slips to permit such setting.

The gear 5 is driven by a pinion 11 which is rotated from the synchronous motor 7 through a gear 13 and other gearing (not shown).

As shown in FIG. 1, a mutilated gear 9 and its hub 9A are die cast as an integral structure which is slidably splined to a shaft 15 for rotation with the interval pointer l. The shaft 15 extends through the sleeve M1 and has a square section 15A which is slidably received in a square opening in the hub 9A. A clapper '17 of soft-magnetic resilient sheet material has one end secured to the plate 3 by means of a rivet l9 and has a second end shaped as a finger 17A riding on the upper face of the gear 9 as viewed in FIG. 1. The resilience of the clapper material biases the finger 17A lightly against the face of the gear. The clapper also has a portion 178 extending adjacent but spaced from the core of a synchronous motor 7. Thus, if the clapper is free, it will vibrate under the influence of the alternating field developed by the motor 7 to produce a buzzing sound. However, when the finger 17A is in engagement with the face of the gear 9 as shown in FIG. 4, the clapper is prevented from vibrating. FIG. 4 isassumed to show the parts in the positions they occupy one-half minute before a buzz position.

In order to release the clapper at the proper time, the gear 9 is provided with an aperture or recess 21 which is so located that at the end of the interval being measured by the rotation of the gear 9 in the direction of the arrow 23 the recess 21 moves beneath the finger 17A to a buzz position shown in FIG. 5 and clears the finger for the purpose of releasing the clapper 17. In this position the mutilated gear is decoupled from its driving source represented by a pinion 25. The resulting buzzing sound produced by the clapper signifies the end of the interval being measured.

The pinion 25 is mounted for independent rotation on the same shaft as the gear 13 and has a slip coupling to the gear through a spring S1. The slip coupling transmits sufi'icient torque to assure timed rotation of the gear 9 by the synchronous motor 7. However, when the knob K is operated to set the interval pointer l, the slip coupling slips to permit such setting.

As shownin FIG. 4 a number of t'eeth are omitted from the mutilated, gear 9. In the buzz position the pinion 25 is adjacent the area of the gear 9 from which the teeth are omitted and consequently is decoupled. I When the buzzer is to be turned off the shaft is rotated manually by the knob K to move the gear 9 to an off position. During such movement the finger 17A.rides over a rib 21A formed on the gear 9 to the off position shown in FIG. 6. In this position the gear prevents vibration of the finger and is still decoupled from its driving source. When a new interval is to be measured the knob K is rotated manually in either direction to move the gear to the desired time position. The mutilated gear now is coupled to its driving source for timed movement by the motor 7 in the dire'ctionof the arrow 23.

When the knob K is pressed downwardly as viewed in FIG". 1 for the purpose of settingthe associated clock, the square section 15A slides downwardly in the hub 9A but the coupling is such that the shaft andthe gear 9 continue to rotate as a unit.

pled positions. When the clutch is incoupled condition rot'a- I tion of the knob K rotates the sleeve M1 and sets the clock in a manner understood in the art. The construction materially simplifies the association of the gear. 9 with the remainder of the assembly and the structure required to control the clapper 17.

, Preferably the gear 9 is die-cast from a suitable diecas ting alloy, such as an aluminum base diecasting alloy. The diecasting operation simultaneously formsthe; hub 9A, the teeth, the recess 21, and the rib 21A. ln addition a shoulder 216 is formed for the purpose of retaining the finger 17A in the off position. However the shoulder 21C and the rib 21A have slopes selected to permit manual mov ementof the gear away from or to the ofi position in eitherdirection by application of a reasonable torque to the knob K such as 9 to 16 inch-ounces. For example the edge 21D of the shoulder which is-adjacent the finger 17A in the off position may be inclined 17 or l8' away from the vertical as shown in FIG. 6.

In effect the finger 17A acts as a cam follower for a cam formed by the face of the gear 9. When the interval'timing mechanism is not in use, the finger 17A occupies the off position shown in FIG. 6. In this position the finger is held displaced against its bias to an extent such'that hand the clapper 17 cannot vibrate.

The off position of FIG. 6 locates the finger 17A in a trough bordered by the rib 21A and the shoulder'ZlC. When a time interval is to be measured, the gear 9 isrotated manually to an angular position corresponding to the interval to be measured. This movement may be either clockwise or'counterclockwise. The configuration of the finger 17A and thetrough are'such that a noticeable torquesuch as 9 to 16 inch-ounces must be applied to move the shoulder 21C to the left as'viewed in FIG. 6. This provides a noticeable stop or dwell feel which informs the operator that he has reached the off position, but permits the operator to move the gear 9in either direction from the off position without requiring-a burdensome physical effort by the operator.

Preferably the parameters'are such that the effort required to move the gear 9 clockwise from the off position is slightly larger than that required to move the gear counterclockwise from the off position: Thisis illustrated in FIG. 6 by the height of the shoulder 21C which is higher than the rib 21A. Moreover the rounded cross section of the rib 21A and the bevel of the finger 17A make it noticeably easier to move rib past the finger 17A than to movethe shoulder 21C past the finger. Such construction further assists the operator in sensing the arrival of the gear 9 at the off position.

Assuming that the gear 9'has been moved to the position corresponding to the'desired interval, the motor 7 now moves the gear 9 at a uniform rate in the direction of the arrow 23 in FIGS. 3 and 4 until'the gear reaches the position represented in FIG. 4 which corresponds to say one-half minute before the expiration of the desired interval. The torque applied b the motor to the gear 9 to produce the timing movement 0 the gear preferably should be relatively small, and preferably shouldbe appreciably less than the torque'required to move the gear away from the off position. During this movement the face of the gear maintains the finger 17Aelevatedagainst its bias sufficiently to prevent vibration of the clapper l7.

Continued motion of the gear 9 finally moves the recess 21 below the finger, and the clapper is now free to buzz, signaling the end of the interval; Also the mutilated gear 9 now presents its tooth-free peripheral portion to its driving gear, and the resultant decoupling assures continuance of the buzz or signal until the gear 9 is reset manually. It should be notedthat'the invention minimizes the number of parts utilized for. providing the-desired operation. The gear 9 is required'for timing purposes. The clapper 17 is required as a source of sound. No other individual part is required. T'h' finger 17A is formed as an extension of the clapper. The cam surface for thefinger 17A to follow is formed on the gear 9.

I claim: v x I 1. An interval timing mechanism comprising a stator structure, a rotor disc mounted for rotation aboutan axis relative to' the structure, motive-means'including an electric motor forrotating saiddisc, said motor when energized producing an alternating magnetic field, a clapper unit resiliently mounted on said stator structure and-having a portion disposed in the magnetic fieldfor application of'a magnetic forceby said field to' produce sound, said clapper unit having a finger, bearing against one surface of said disc to prevent-vibration of the clapper unit over'a substantial range'of rotation of said disc, said disc surface having a-recess for receiving the finger in a first angular position of said disc to fre'e'the clapper unit for vibration by said field to produce sound,- said disc surface having a configurationat'a'second angular position of said disc comprises a mutilated gear, said motive means comprising:-

gearing coupling-the mutilated gear to the motor, said m'utilated gear having no teeth engagingsaid gearing when the disc occupies said first and second angular positions, said mutilated gear including said disc surface being constnicted integrally of homogeneous material.

3. Mechanism as claimedin claim 2 wherein said rriu'tilated gear including said disc surface and said recess is molded from a molding material.

4. Mechanism as claimed in claim 2 wherein said disc surface comprises one face of said mutilated gear, said recess extending axially from said one'face, said configuration comprising a trough in said one facefor receiving said finger, the walls of said trough permitting rotation of said disc in eachdirectiom to force the finger out of the trough.

5. Mechanism as claimed in claim 4 wherein said trough and finger are configured to require a larger'torque to produce rotation of therotor disc in one direction than the torquerequired to produce rotation'of the rotor disc in the other direction awayfrom the second angular position.

6. Mechanism as claimed in claim 5 'wherein said mutilated gear including the disc surface are molded fr'oma die'castin'gj metal alloy.

Claims (6)

1. An interval timing mechanism comprising a stator structure, a rotor disc mounted for rotation about an axis relative to the structure, motive means including an electric motor for rotating said disc, said motor when energized producing an alternating magnetic field, a clapper unit resiliently mounted on said stator structure and having a portion disposed in the magnetic field for application of a magnetic force by said field to produce sound, said clapper unit having a finger bearing against one surface of said disc to prevent vibration of the clapper unit over a substantial range of rotation of said disc, said disc surface having a recess for receiving the finger in a first angular position of said disc to free the clapper unit for vibration by said field to produce sound, said disc surface having a configuration at a second angular position of said disc within said range coacting with said finger for inhibiting movement of the disc away from said second angular position, said configuration permitting movement of the disc away from the second angular position in each direction in response to an application of torque thereto only if such torque is larger than the torque required to rotate the disc over a substantial part of said range.

2. Mechanism as claimed in claim 1 wherein said rotor disc comprises a mutilated gear, said motive means comprising gearing coupling the mutilated gear to the motor, said mutilated gear having no teeth engaging said gearing when the disc occupies said first and second angular positions, said mutilated gear including said disc surface being constructed integrally of homogeneous material.

3. Mechanism as claimed in claim 2 wherein said mutilated gear including said disc surface and said recess is molded from a molding material.

4. Mechanism as claimed in claim 2 wherein said disc surface comprises one face of said mutilated gear, said recess extending axially from said one face, said configuration comprising a trough in said one face for receiving said finger, the walls of said trough permitting rotation of said disc in each direction to force the finger out of the trough.

5. Mechanism as claimed in claim 4 wherein said trough and finger are configured to require a larger torque to produce rotation of the rotor disc in one direction than the torque required to produce rotation of the rotor disc in the other direction away from the second angular position.

6. Mechanism as claimed in claim 5 wherein said mutilated gear including the disc surface are molded from a diecasting metal alloy.

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