US1851593A - Stop watch - Google Patents

Description

March 29, 1932. PASTOR 1,851,593

STOP WATCH Filed Feb. 3, 1950 Zlwucm/bo b 177cm; Pasi'or' 3 (BLJKOQWQk THOMAS PASTOR, OF WATER-BURY, CONNECTICUT STOP WATCH Application filed February 3, 1930. Serial No. 425,494.

This invention relates to Stopwatches and more particularly to those embodying the time-piece features.

This invention has for its objects, among others, first, to improve the instruinentality for holding the sweep hand in the inoperative position and second, to provide means whereby when the operative mechanism is thrown into mesh a minimum of vibration is imparted to the sweep hand. Other objects are to facilitate a quick and accurate assembly in manufacture by eliminating one spring and so constructing and positioning another spring that it does the work both of itself and the eliminated spring in the way also lowering the manufacturing cost.

Reference is made to the drawings which are hereby made a part of this specification in which Figure 1 is a plan view of a stopwatch of the class described with the back removed.

Figure 2 is a view similar to Figure 1 but with the detent lever removed,

Figure 3 is a section along the line 3-3 of Figure 1 as viewed from the left, and

Figure is a plan view of the combined tension and friction spring.

Similar numerals of reference indicate like parts throughout the drawings in which letter A designates the back plate which in the model shown is a single fiat disc a part of which is cut away (not shown) for access to the hairspring. A fine-toothed wheel 1 is mounted to turn continuously on the third wheel pinion extended through the back plate. This wheel is adapted to mesh with and actuate a fine-toothed pinion 2 secured to the needle stafi 15. A detent lever 3 is mounted on and is adapted to oscillate on a pillar 2O fatten-ed in the backplate A. The longer arm of the L-shaped detent lever .3 engages the surfaces of a castle cam 4, which has six equidistant caniming surfaces with six recesses therebetween and which is rotatably mounted on the back plate A. Mounted beneath and pinned to the castle cam 4t and rotatable therewith in a clockwise direction only under the control of the click-spring pawl 5 which meshes with the ratchet teeth, is a ratchet 6 having eighteen equidistantly spaced teeth adapted to be engaged in turn by the push lever 7 which has a thumblike extension 7a and aslot 8 therein which in cooperation with the setscrew 9 fastened in the back plate, limits the thrust of said lever. A spring 10 secured to the back plate, engages the thumb 7a tending to hold the push lever 7 in the retracted position. A push pin 11 radially mounted in a bushing in the centerband engages a tab or rightangled extension (not shown) of the push lever 7. The fiyback lever 12, adapted to oscillate on a pillar on the backplate has a thumb 152a adapted to engage and interact with the castle cam t and its recesses, being held in continuous engagement therewith by a coil spring 13. When the thumb 12a is in a recess as shown in Figure 1, the end 126 engages the heart cam 14-, which is fast to the needle staff 15 which in turn has a bearing in the short arm of the detent lever 3. Within the center wheel 17, which rotates between the front plate B and the back plate A. is a small axial cylindrical core against the lower inner wall of which a small collet 18 fast on the needle stall 15, rotates. A movement of the short arm of lever 3 in which staff 15 has a bearing, carries the pinion into and out of mesh with the fine-toothed wheel 1. The spring 16 both carries th pinion into meshing position and when the pinion is out of mesh also holds the staff 15 and with it the sweep hand 19 against turning. This spring embodies an improvement over the construction shown in my Patent No. 1,493,125.

Referring to Figure 4- the sprin 16 is preferably made of small steel wire and at approximately the middle has V -shaped bend the inner edges of which are adapted to press against the staff 15; the end of extension is adapted to lie a ainst the pillar 20 while the opposite end or the spring has a bentback extension 22 by which the spring 16 is adapted to be secured to the back plate A by stud 16a fast in the plate. The spring 16 as mounted, is always tending to press the staff 15 and with it the pinion 2 into meshing or actuating engagement with the fine-toothed periphery of the continuously rotating chronograph wheel 1, in this manner giving to the sweep hand 19 a quick and unretarded start without any lost-motion whatsoever. By means of the snug fit of the bearing of the detent lever 3 on the pillar 20, which is 53 easily accomplished with simple watchmakers tools, I practically eliminate any movement of the shaft varies the frictional engagement of the V-bend therewith. Signed at Waterbury, in the county of New Haven and State of Connecticut, this twentyninth day of January, A. D. 1930.

THOMAS PASTOR.

lost-motion or retarded action and thereby produce. in a simple, and inexpensivmmecha nism a quicker start of the sweep hand than 39 is obtainable in the more expensive stopwatches that possess maore compl-icated aetuated mechanism. The very quickness of the start, although enhancing the actual recording precision of the.instrument,.none-.the less would often cause a vibration of the staff and a'simultaneous vibration of the .sweephand .19- as it starts to register on the dial, which :vi-bration: often creates 'the -er :roneous-idea in themin'd of the user that a 'gamer loss is being accumulated'bythe instrument 1 in starting. This :BIIOIIEOHS idea SQIlOUSly lessens the utilityof the lnstrument andit isimportant tollimit' the sweep hand. 7 vibration instarting. The stafi 15 lies .be- I.

r tweenthe inner edge's of the V-shaped bend 24:

in the-spring 16. W hen the-staff 15. is moved :awayfrom the-wheelE-l bythe movement of detent lever.8 .in'which it has: a' bearing, the

:sta'fi j presses .harder into the lleshaped porution :QAritl'lCl. pushesthe spring :16 back, in

this manner simultaneously increasing its tension and ,-so the Y inner edges of the EV- shaped portion. grip the staft'xl5 more tightly. This friction grip.- overcomes all. other i tric- :tion and prevents :anyi friction thatmay .be :rleveloped by? the sta'fi' or its-collet 18 from turning: the sweep hand19- when the actuat- ..-ing wheel .1. and: pinion.;2: are out: of mesh. 'On the other handwhen the stopwatch is started and thestafl :15 travels toward the -wheel l the :friction grip of the Vepart. :24: -.-is -lessened gradually, the inner ,edges:.still steadying thesta'fi 151 and preventing vi-bra- *tioniasthelpoints of the teeth on the pinion 2 pick up -.the;points1 ofrtheteeth on 1 wheel 1. Obviously in those cases of; engagement when the coincidence of teeth is point to point there r :is then the greatest tendency to vibration -.of the sta1f1-5 andsimultaneouslyto oscilla- 59 tion of thesweep hand 19 inithis position the inner edges of. the- -v"-shaped; part. 124; are still in sufficient tension contact with the staff- 15 :to prevent? vibration until theteethhave-sunk

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