US1493125A - Stop watch - Google Patents

Description

T. PASTOR STOP WATCH Mayfe", 1924.

Original Filed Nqv. 25. 1919 mm H 0.. W wM m n. A

Patented May .6, 1924.

UNITED STATES 1,493,125 PATENT OFFICE.

THOMAS PASTOR, OF WATERBURY, CONNECTICUT, ASSIGNOR, BY MESH-E ASSIGN- MENTS, TO THE STERLING WATCH COMPANY, INC., A CORFORATION OF NEW JERSEY.

STOP WATCH.

Application filed November 25, 1919, Serial No. 340,639. Renewed October 22, 1923.

T 0 all whom it may concern:

Be it known that I, THOMAS PASTOR, a citizen of the United States, and a resident of ater-bury, in the county of New Haven and State of Connecticut, have invented certain new and useful Improvements in Stop \Vatches, of which the following is a specification.

This invention relates to that class of chronometers generally designated as stop watches and has for its object to provide a simple, durable, and eflicient mechanism that can be cheaply manufactured and readily attached to the popular low-priced watch now on the market, so that a stop watch may be sold at a price within the reach of students, sportsmen, factory foremen and inspectors, and all who may desire to time acts or movements to the fraction of a second.

This invention makes use of some old and well known principles heretofore utilized in this art to procure the same end, effects a change in relationship of parts to produce a simple, compact, and yet effective train of operative mechanism, and improves certain elements in the train to make a more positive, accurate, and durable movement than has heretofore been effected with so simple and cheaply manufactured a structure.

A specific embodiment of this invention is shown in the accompanying drawing in which Figure 1 is a view of the face of alowpriced watch equipped with a stop hand. The stop hand is at 12 in the inoperative position.

Figure 2 is a view of the back of the watch with the back of the watch case removed. The stop movement is in the inoperative position.

Figure 3 is a view of the stop movement similar to that of the preceding figure, but with the actuating cam removed and the L shaped bell-crank lever shown in dotted lines. The stop movement is in operative position.

Figure 4 is an enlarged section through the watch from back to front, with the back of the watch case and the watch crystal re moved, showing the central arbor, which carries the stop hand, in operative position.

Figure 5 is a section similar to that in the preceding figure showing .the arbor in slightly exaggerated inoperative position.

Referring to Figure 1,v it is noted that the dial of the ordinary watch comprises hour and minute hands that rotate about the center of the dial. The circumference of the outer edge of the dial is graduated into sixty equal divisions or minutes. Inasmuch as the second hand is placed off-center on the dial a separate scale is necessary to indicate the seconds, but it is obvious that if the second hand rotated on the axis of the dial the minute graduations on the circumference of the dial would also indicate the seconds. In certain types of stop watches the supplemental second or stop hand, which is to be used to indicate the time interval in seconds, is mounted on an arbor that projects through the center of the dial and rotates over the hour and minute hands between the latter and the watch crystal. Supplemental graduations of the minute divisions into fifths, or any desired fraction, are made to facilitate readings in fractions of seconds. In the inoperative position this stop hand rests at 12.

In Figure 2 the watch has been turned over and the back of the watch case removed, and an analysis of the structure of the present invention is now possible. The back plate of the watch movement is shown diagrammatically and is designated by the reference character A. Parts of the watch movement are ordinarily exposed but in order not to divert the attention from the structure of the stop movement the plate A is shown as a solid disc.

On the edge of the watch case, conveniently removed from the stem, is a push pin 11, having a rounded head adapted for actuation by a finger or thumb to start the movement of the stop hand, to stop the movement of the stop hand, and to return the stop hand to the initial position over the 12, successively, by pushing on the pin 11 and withdrawing the pressure, three times.

Referring to Figure 2, it is noted that there are five main operative parts shown, a fine-tooth wheel 1, an L-shaped bell-crank lever 3, a rotating cam 4, a slide 7, and a stop-resetting lever 12. These parts are neatly and compactly arranged on the back plate approximate to a geometrical diameter traced through the push pin 11 and the center of the watch, with the purpose of expediting the assemblyv of the stop movement in manufacture and easy adjustment and testing of the parts.

The wheel 1 is mounted to rotate continuously on the axis of the third wheel of the watch movement, which wheel is designated by watchmakers as the seconds wheel or third pinion. The periphery of this wheel is provided with fine teeth, which in manufacture may be impressed by rolling. These teeth are adapted to mesh with the teeth of a small pinion 2 fast on the arbor 15, which carries the stop hand 19, when the stop movement is in operative position. The relative number of teeth on the wheel 1 and the pinion 2 are determined by anyone skilled in the art by consulting proper tables prepared for the purpose.

The L-shaped bell-crank lever 3 is mounted to oscillate on a screw stud secured to the back plate A at a point above the wheel 1 and to the left of a geometrical line through the push pin 11 and the center of the watch. In the short arm of the L-shaped bell-crank lever 3 is a cylindrical aperture to provide a bearing for the upper end of the stop-hand arbor 15, and the end of the long arm of the L-shaped bell-crank lever is in contact with the cam 4. It isapparent that the movement of the arbor 15 through the small space sufficient to disengage the teeth of the pinion 2 from the teeth of the pinion 1 is practically in a straight line perpendicular to the tangent at the point of contact between the wheel 1 and the pinion 2, and that this line coincides with the geometrical diameter through the push pin 11. It will be noted further that the L-shaped bell-crank lever 3 is the element of the stop movement most elevated above the back plate A and substantially entirely disposed in a central zone on the back plateA. The advantage of this arrangement becomes apparent when it is considered that the back of a watch case is usually convex on the outside, and similarly concave on the inside with the maximum of convexity or concavity at the center of the back of the case, with the result that no special back for the case of the watch is required when this stop movement is attached to one of the several low-priced watches now on the market.

The cam 4 is mounted to rotate on a stud screwed into the back plate A at a point to the left of the geometrical diameter through the push pin 11. The cam 4 is in the form of a circular disc, the circumference of which is intercepted by three concavities the centers of which are 120 degrees from each other, so that the cam 4'consists of three cam surfaces each of which is effective through eighty degrees or two-ninths of the circumference, or in one complete rotation of the cam 4 the surfaces are effective three times, each through two-ninths of one rota tion, and. the concavities are effective as stops three times, each every third of a rota,

tion of a complete circumference. In thickness the cam disk 4 is equal to the sum of the bell-crank lever 3 and the stop-resetting lever 12.

The stop-resetting lever 12 is mounted on a stud to the right of the line through the center of the back plate and the push pin 11. The stud is screwed into the back plate A and is provided with a suitable screw cap at the proper elevation from the back plate. The stud acts as a pivot for a coil spring 13, one end of which is secure in the back plate and the other end fastened to a pin on the lower side of the lever 12. This spring 13 tends to swing the lever 12 in a clockwise direction toward the arbor 15 and the cam 4. The stop-resetting lever is provided with a thumb 12 adapted for continuous contact with the surfaces of the earn 4, and a finger 12 adapted for intermittent contact with the heart cam 14 which is of usual construction, well known to those skilled in the art. It is apparent that when the thumb 12 is in contact with any of the three surfaces of the cam 4, the finger 12 is held out of operative position and that when one of the three concavities in the cam 4 is presented to the thumb 12, the spring 13 acts to force the finger 12 into operative contact with the heart cam 14.

The heart cam 14 is fixed to the arbor .15, which carries the stop hand 19. The stop hand is so positioned on the end of the arbor that when the finger 12 of the stop lever is in contact with the concavity of the heart cam, that is, the point of contact at which there exists stability of the heart cam on its pivot, the stop hand registers 12 or the zero point on the minute scale of the watch dial.

The slide 7 is provided with a slot 8. A stud passed through the slot secures the slide to the back plate on which it is adapted to slide and oscillate slightly to the left and right about the stud. An exten sion from the slide (not shown) passes through an aperture in the plate somewhat larger than the extension and is engaged by the push pin 11. The slide 7 is-provided with a thumb 7 the inner surface of which is engaged by a spring 10 suitably secured to the back plate and adapted to exert pressure radially outwardly.

Referring to Figure 3, in which the L shaped bell-crank lever 3, together with the cam 4, have been removed to show the parts underlying, it is seen that a ratchet wheel 6, which is provided with nine ratchet teeth, is engaged on the right side by the finger of the slide 7 which is adapted to actuate it in a clockwise direction, one-ninth of a complete rotation upon each full inward move-' ment of the slide 7 or the push pin 11 which actuates the slide, and is engaged on the left side by the end of a spring that engages the ratchet and holds it positively against counterclockwise movement and resiliently and frictionally against clockwise movement. This ratchet wheel 6 is secured to the cam 4 and therefore moves with and controls the movement of the cam. This cam 4 might be called a clover-leaf cam and the ratchet wheel 6 associated therewith having in the present case nine teeth is so constructed as to have a definite ratio, that is, three to one between the number of its teeth and the number of leaves to the cam.

In Figure 3 the stop-resetting lever 12 is shown in retracted position as if the thumb 12 were bearing on one of the three cam surfaces of the cam 4. The L-shaped bellcrank lever is shown in dotted lines as if the end of the longer arm were in engagement with one of the three concavities in the cam 4. In this position of the lever 3 the pinion 2 is in operative engagement with the wheel 1 and the stop hand or auxiliary second hand 19 rotates about the dial of the watch case once in each sixty seconds.

The movement of the arbor 15 toward the wheel 1, and therefore of the pinion 2 toward the wheel to intermesh therewith, is effected by means of a main spring 16. This spring is formed from a flat strip bent at suitably removed points to form loops. The loop at one end has a small extension. This loop is adapted to surround the arbor and provides a stop, for the pinion 2 is fast on the arbor 15, against downward movement of the arbor, as clearly shown in Figures 4 and 5. The loop on the right side has a longer extension so that not only is a pivotal bearing on the back plate afforded for the spring but the extension affords a ready means of adjustment of the tension of the spring as a whole, the extension being adapted to bear near its end against a stop in the plate. The loop of spring 16 about the arbor 15 has an important function in that it prevents vibration of the stop head 19 upon starting or stopping in the inoperative position of gears 1 and 2 or immediately before or after they are interacting in the operative position of the stop attachment. The width of the flat strip is such that the spring lies entirely beneath the plane of movement of the stop-resetting lever 12, which is in turn beneath the plane of movement of the bell-crank lever 3.

Referring more particularly to Figures 4 and 5, the center wheel 17 is shown mounted in the plates A and B of the watch move ment. The center wheel 17 is provided with an axial cylindrical bore extending through the wheel. The arbor 15 is a cylindrical pin of steel having near its lower end a disk 18. This disc 18 and the approximate wall of the bore form a bearing for one end of the arbor 15.

Above the back plate A arise successively the extension of the spring 16 turned back to form a loop about the arbor and a stop against the downward movement of the arbor, the pinion wheel 2 fixed to the arbor, the heart cam 14, as shown its projection to the left and its concavity on the right, and the short arm of the L-shaped bell-crank lever 3. As'shown in Figure 4 the arbor 15 is in operative position with the pinion 2 as if in mesh with the wheel 1, and in Figure 5, somewhat exaggerated to show the principle of operation, the upper-end of the arbor 15 is bent to inoperative position in which the pinion 2 is out of engagement with the wheel 1, and the stop hand on the dial is in position for reading the duration of time elapsed in seconds and fractions thereof.

From the foregoing particular and distinct description of the parts and their relationship, the movement is clearly evident.

The first push on the push pin 11 throws the thumb 12 from the concavity of cam 4 so that the finger 12 is released from the heart cam 14. Simultaneously the end of the long arm of the bell-crank lever 3 sinks in a concavity in the cam 4, permitting movement of the lever on its pivot brought about by pressure of the main spring 16 on the arbor 15 which has a bearing in the short arm of the bell-crank lever 3, in this manner bringing the pinion 2 into mesh with the Wheel 1. Upon the first push therefore, the stop hand 19 commences to rotate from zero position over 12, and traverses the circumference of the dial once in each sixty seconds.

The second push on the push pin 11 throws the long arm of the bell-crank lever out of the concavity in the cam 4 and carries the short arm, and together with itthe arbor 15 and pinion 2 directly away from wheel 1. The lever 12 is still held by the cam surface in retracted position, its finger 12 removed from the heart cam 14. Upon the second push therefore the stop hand ceases to move and a reading on the dial may be made.

The third push on the push pin 11 permits the spring 13 to throw the lever 12 in a clockwise direction and to bring the thumb 12 into the next concavity in the cam 4,

simultaneously bringing the finger 12 into 1 engagement with the heart cam 14. Upon the third push therefore the stop hand is re set at the initial or zero position over 12 on the dial.

It is apparent from the foregoing that a simple, durable and effective mechanism has been produced, in which have been secured a compact arrangement of parts, a maximum of mechanical perfection with a minimum of parts, simplicity and durability of structure, readiness of removal for cleaning, adjustment and repair, facile adjustment of the tension of the main spring of the stop movement, and the positive locking of every part against jarring.

It is further apparent that in adapting my invention to the low-priced watches now in use the only modification of the watch move ment necessary is the provision of an axial bore in the center wheel.

It is apparent that modifications may be made within the scope of my invention and I do not'limit myself except as in the appended claims:

I claim:

1. In a stop movement for low-priced watches, in combination a center wheel having a cylindrical bore extending therethrough, an arbor adapted to extend through said bore and carry a stop hand on its outer end, means forming a bearing for moving the inner end of the arbor into inoperative position, a spring bearing .on said arbor and tending to move said arbor into operative position, and a circular disc fast on said arbor near its lower end and disposed within said cylindrical bore.

2. In a stop movement for low-priced watches, in combination a center wheel having a cylindrical bore extending therethrough, an arbor adapted to extend through said bore and carry a stop hand on'its outer end, means forming a bearing for moving the inner end of the arbor into inoperative position, a spring bearing on said arbor and tending to move said arbor into operative position, and means for adjusting the tension of said spring, and a. circular disc fast on said arbor near its lower end and disposed within said cylindrical bore.

3. In a stop movement for low-priced watches, in combination a center wheel having a cylindrical bore extending there: through, an arbor adapted to extend through said bore and carry a stop hand on its outer end, means forming a bearing for moving the inner end of the arbor into inoperative position, a spring bearing on said arbor and tending toimove said arbor into operative position, said spring having an extension whereby the tension of the spring on the arbor may be adjusted and a circular disc fast on said arbor near its lower end and disposed within said cylindrical bore.

4. In a stop movement for low-priced watches, in combination a center wheel having a cylindrical bore extending therethrough, an arbor adapted to extend through said bore and carry a stop hand on its outer end, means forming a bearing for moving the inner end of said arbor, into inoperative position, a spring having a loo-p about and bearing on said arbor and tending to move said arbor into operative position, and a circular disk fast on said arbor near its lower end and disposed within said bore.

5. In a stop-watch having a split-seconds hand adapted to turn over the dial of the watch, in combination a center wheel provided with a cylindrical bore, an arbor having a part adapted to form a bearing on the inner wall of said bore, and a spring mounted on the back-plate and looped about the arbor so as to provide suiiicient friction to prevent the turning of the arbor in the bearing while the center wheel is turning.

6. A stop movement for low-priced watches, comprising in combination a center wheel having a cylindrical bore extending there through, and an arbor extending through said bore and having on one end a removably mounted stop hand, said arbor comprising a cylindrical pin of steel which has a disc fixed thereto that is adapted to form with the bore a bearing for the arbor.

7 In a stop movement for low-priced watches, in combination a center wheel having a cylindrical bore extending therethro-ugh, an arbor extending through said bore, said arbor having a disc secured thereto, the disk forming with said bore a bearing for the arbor near one end, a fine-tooth pinion fast on said arbor and adapted to mesh with a fine-tooth wheel mounted to turn with the third wheel of a watch movement, and an L-shaped bellcrank lever adapted to throw said pinion into and out of mesh with said wheel, the short arm of said bell-crank lever having a bore to provide a bearing for the other end of said arbor.

8. In a stop movement for low-priced watches, in combination a center wheel having a cylindrical bore extending therethrough, an arbor extending through said bore, said arbor having a disc secured thereto, the disk forming with said bore a bearing for the arbor near one end, a fine-tooth pinion fast on said arbor and adapted to mesh with a fine-tooth wheel mounted to turn with the third wheel of a watch movement, a spring adapted to hold said arbor in operative position, said spring having a loop about said arbor which acts as a stop against downward movement of said arbor, and an Lshaped bell-crank lever adapted to throw said pinion into and out of mesh with said wheel, the short arm of said bell-crank lever having a bore for the end of said arbor adjacent the pinion.

9. Ina stop movement for low-priced watches, in combination a center wheel whose arbor has a cylindrical bore extending therethrough, an arbor extending there through on one end of which is mounted a stop hand, said arbor having-a disk secured thereto near its lower end,said disk forming with said bore a bearing for the arbor near one end, and an L-shaped bell-crank lever having a cylindrical bore in its shorter arm forming a bearing for the upper end of said arbor, and a flat spring tending to bent to form a loop about the arbor and to form a second loop about a pivot on the back plate, the end of the second loop being extended and positioned against a stop on the back plate so that adjustment of the tension of the spring may be readily efi'ected by bending this extension.

10. In a stop-Watch having three movements of actuation to start, stop and reset a. split-seconds hand, in combination a spring-retracted push-pin, a combined ratchet wheel and circular cam pivotally mounted on the back-plate of the watch and adapted to be rotated by said push-pin, a finger pivotally mounted at one side of the cam and having a resilient contact with the said side of the cam, an L-shaped bellcrank lever pivotally mounted on another side of the cam and having its long arm positioned to be actuated by the cam, and the short arm adapted to form a bearing for an arbor on the other end of which the split-seconds hand is mounted, and a spring bearing on the arbor and tending to bring said long arm of the bell-crank lever in contact with said cam.

11. A stop movement for low-priced Watches, comprising in combination a push pin mounted in the edge of the watch case and engaging an extension on a spring retracted slide mounted for radial and slight lateral movement on a stud secured to the back plate of a watch movement, a ninetooth ratchet wheel mounted to rotate on another stud and held in position by a spring after movement by the slide through one ninth of a circumference, a cam secured to the ratchet wheel, said cam having three surfaces in the same circumference separated each from the other by a curved depression, each of said cam surfaces being effective through two-ninths of a circumference, an arbor adapted to swing out of the axial line of its bottom bearing an Lshaped bellcrank lever mounted on a stud centrally disposed on the back plate, the end of the long arm of said lever being adapted to engage said cam surfaces, and the short arm of said lever providing a bearing for the top of said arbor which carries a stop hand on the other end thereof.

12. A stop movement for low-priced watches, comprising a fine-tooth wheel mounted on the back plate of a watch movement to turn with the third wheel of the movement, a push pin mounted diametrically opposite said wheel, a slide mounted to move on said diameter, a ratchet Wheel in the path of said slide adapted to be actuated thereby, a cam above said ratchet and se cured thereto, a stop-resetting lever on' one side of said diameter having a thumb adapted to engage said cam, a coil spring fixed to said lever and said back plate serving to press said lever toward said diameter, an L- shape bell-crank lever mounted on the opposite side of said diameter, said bellcrank lever being adapted to oscillate in a plane above said stop-resetting lever, a spring mounted on said back plate beneath said lever and adapted to engage said ratchet, an arbor carrying a stop hand and having a bearing in the short arm of said bell-crank lever, said arbor being adapted to swing in a line approximately coincident with the diameter, aheart cam mounted on said arbor below said bearing, a finger on said stop-resetting lever adapted to engage said heart cam, a fine-tooth pinion mounted on said arbor beneath said heart cam, and a fiat spring mounted on the back plate forming a loop about the arbor beneath the pinion and having a second loop about a pivot to provide an extension for ready adjustment of the tension of said spring by bending said extension.

13. In a stop Watch, in combination, an arbor bearing a sweep-second hand, a center wheel provided with an axial core, said arbor having a bearing within said core, the opposite end of said arbor having a bearing in a laterally movable lever, a pinion mounted on the arbor for turning the arbor, a gear mounted on the seconds wheel, and means for preventing vibration and downward movement of the arbor as said gears intermesh or unmesh.

14. In a stop Watch, in combination, an arbor bearing a sweep second hand, a center wheel provided with an axial core, said arbor having a bearing within said core, the opposite end of said arbor having a bearing in a laterally movable lover, a gear mounted on the arbor for turning the arbor, a gear mounted on the seconds wheel, and a spring looped about the arbor for preventing vibration of the arbor as said gears intermesh or unmesh.

15. In a stop watch, in combination, an arbor bearing a sweep second hand, a center wheel provided with an axial core, said arbor having a bearing within said core, the opposite end of said arborhaving a bearing in a laterally movable lever, a gear mounted on the arbor for turning the arbor, a gear mounted on the seconds wheel, and a spring looped about the arbor and bearing upon the arbor from opposite sides for preventing vibration of the arbor as said gears intermesh or unmesh.

16. A stop movement for low priced watches, comprising in combination a push pin mounted in the edge of the watch case and engaging an extension on a spring retracted slide mounted for radial and slight lateral movement over a stud secured to the back plate of a watch movement, a ratchet wheel mounted to rotate on another stud, a clover-leaf cam secured to the ratchet wheel, said ratchet wheel having teeth proportionate in number to depressions on the periphery of said cam, said ratchet wheel being held in position by a spring after movement by said slide through a definite angular travel, and an L-shaped bell-crank lever mounted on a stud centrally disposed on the back plate, the end of the long arm of said lever being adapted to engage said cam surfaces, and the short arm of said lever providing a bearing for the top of an arbor which carries a stop hand on the other end thereof, a looped spring enveloping said arbor, and frictionally holding the same against vibration said L-shaped lever being pivoted at the union of the long and short second bearing laterally, a driving pinion,

arms. 1 r y 17. In a stop movement for-low priced watches, in combination center wheel having a cylindrical core extending therethrough, an arbor adapted to extend through said core, and to carry a stop hand'at its outer end, a bearing on said. arbor near its lower end, said bearing comprising a relatively narrow disk co-acting with said cylindrical core a second bearingnear the inner end of said arbor, means-for moving said second bearing laterally and a driven pinionon said arbor adapted to be moved to or out of operative position with a driving wheel as said arbor is moved laterally.

18. In a stop movement for low-priced watches, in combination, a center wheel having a cylindrical core extending therethrough, an arbor adapted to extend through said core and carry a stop hand at its outer end, means forming a bearing on said arbor near its lower end and disposed within said cylindrical core, means forming a second second bearing being adapted to move said arbor laterally into inoperative position, a spring adapted to prevent downward movement bearing on said arbor tending to move said arbor laterally into operative position, and apinion on said arbor adapted to be moved to or out of operative position with a driving wheel due to lateral movement of said arbor.

19. In a stop watch, in combination, a split second arbor carrying a hand at one end, a bearing. mountedon said arbor near said hand, a second bearing near the other end of said arbor, means for moving said and a driven pinion on said arbor adapted to be carried into and out of mesh with the driving pinion as said bearing is moved laterally.

20. In a stop movement for watches, in

combination, a center wheel having a bore therein, an arbor extending through said bore and journaled therein, a fine-toothed pinion fast on said arbor and adapted to -1nesl1 with a fine-toothed wheel mounted to turn with the third wheel of a watch movement, a spring adapted to hold said arbor in operative position and against downward movement, and an L-shaped bell-crank lever adapted to throw said pinion into and out of mesh with said wheel, one arm of said bell-crank lever having a bore for the end of saidarbor adjacent the pinion. V

Signed at Waterbury, in the county; of New Haven and State of Connecticut, this day of November 18, A. D- 1919.

THOMAS PASTOR.

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