US3665698A

US3665698A - Electromechanical clockwork with decoupling mechanism

Info

Publication number: US3665698A
Application number: US90572A
Authority: US
Inventors: Peter Dome
Original assignee: Fabrique dHorlogerie CHS Tissot et Fils SA
Current assignee: Tissot SA
Priority date: 1969-11-22
Filing date: 1970-11-18
Publication date: 1972-05-30
Anticipated expiration: 1989-05-30
Also published as: DE2056829A1; JPS494348B1; CH1735369A4; GB1315689A; FR2068594B1; FR2068594A1; CH516185A

Abstract

A continuously operating rocking member coacts with a pair of meshing pinions to step a gear train of a clockwork for a watch, one of the gears of this train being in mesh with the first pinion and being also positively coupled with the seconds hand of the watch incorporating the clockwork. Manual actuation of a release mechanism, preparatorily to the resetting of the watch hands, trips a lever which retracts the other pinion from the sweep of the drive member and also immobilizes the driven gear in mesh with the first pinion, enabling continued reciprocation of the rocking member during readjustment of the timepiece.

Description

nited States Patent Diime 51 May 30, 1972 [54] ELECTROMECHANICAL CLOCKWORK WITH DECOUPLING MECHANISM 211 App]. No.: 90,572

[30] Foreign Application Priority Data Nov. 22, 1969 Switzerland ..l7353/69 [52] US. Cl ..58/23, 58/855 [51] Int. Cl; ..G04c 3/00, G04b 27/06 [58] Field ofSearch ..58/23,23 TF, 28 R, 28 D, 85.5

[56] References Cited 7 UNITED STATES PATENTS 3,470,687 10/1969 Tsuneyoshiono et a1. ..58/85.5

FOREIGN PATENTS OR APPLICATIONS 1,255,852 5/1960 France ..58/28 D Primary ExaminerStephen J Tomsky Assistant Examiner-Edith C. Simmons Attorney-Karl F. Ross [57] ABSTRACT A continuously operating rocking member coacts with a pair of meshing pinions to step a gear train of a clockwork for a watch, one of the gears of this train being in mesh with the first pinion and being also positively' coupled with the seconds hand of the watch incorporating the clockwork. Manual actuation of a release mechanism, preparatorily to the resetting of the watch hands, trips a lever which retracts the other pinion from the sweep of the drive member and also immobilizes the driven gear in mesh with the first pinion, enabling continued reciprocation of the rocking member during readjustment of the timepiece.

10 Claims, 3 Drawing Figures SFCONDS Patented May 30, 1972 foo SE'CgNDS ENERGY 4 /0b somecL= v Pefer Dbme In venfor:

Attorney ELECTROMECHANICAL CLOCKWORK WITH DECOUPLING MECHANISM My present invention relates to an electromechanical clockwork for a timepiece, including a driving mechanism serving to step an input element of a gear train in the rhythm of the oscillation of a balance wheel acting upon a rocking lever or the like, a source of electric energy being provided to compensate for frictional losses and to keep the system going. Such an electromechanical clockwork must be provided with means similar 'to those of ordinary clocks and watches for resetting the hands of the timepiece upon decoupling them from their driving mechanism to which they may be connected by a normally engaged friction clutch.

The gear trains used in such clockworks generally form a stepdown transmission between a relatively fast-moving gear, positively coupled with the seconds hand, and slower-moving gears coupled with the minute and hour hands, respectively. Conventional decoupling mechanisms, designed to permit a resetting of only the latter hands, nevertheless may transmit a residual torque to the gear operatively engaging the seconds hand. This may lead to a temporary jamming which could arrest the drive if the latter is not of the self-starting type. Moreover, the continuing advance of the seconds hand usually prevents precise synchronization with, say, a radio signal.

An important object of the invention is to provide simple and reliable means in an electromechanical clockwork of this general type for enabling resetting of the hands with avoidance of the aforestated drawbacks and without interruption in the operation of the stepping drive, thereby avoiding difficulties which could arise upon the restarting of that drive.

A related object is to provide means for arresting a fastmoving gear, coupled with the seconds hand, in a desired position of that hand (e.g. at seconds) during the resetting of the minute and hour hands.

These objects are realized, in conformity with my present invention, by the provision of a pair of meshing pinions confronting a rocking member, driven by mechanical balancing means sustained by electric energy, which alternately engages the teeth of these pinions in their normal operative position; one of these pinions is in mesh with a driven gear coupled directly or indirectly with the seconds hand of the timepiece, this gear being arrestable by a detent which is entrained by the conventional decoupling and resetting mechanism andwhich also moves the other pinion out of the range of the rocking member so that the latter swings ineffectively until the nonnal position is restored.

The alternate engagement of the rocking member with the two pinions steps the driven gear by one tooth division during every reciprocating of this member, each swing of the latter advancing this driven gear by a half-step. Thus, in order that the drive member may swing freely during the idle phase, the detent arrests a tooth of the driven gear only in a position into which it has been rotated by a stepping of the first pinion.

The second pinion may or may not remain in close mesh with the first pinion on being moved out of the range of the drive member by the resetting control. In the first case, the second pinion may be mounted on a planet carrier fulcrumed on the axis of the first pinion for displacement by the resetting control; in the second instance, this control may act upon an independently fulcrumed lever with an extremity carrying the second pinion. In an advantageous embodiment, this latter lever may have three arms, one of them supporting the second pinion while another carries the detent for the driven wheel and a third one yieldably abuts a fixed stop to hold the system in its operative position in which the teeth of the second pinion lie in the swing path of the drive member. The swing of the control lever into its alternate position should be limited to prevent complete separation of the two pinions, thereby facilitating their return to normal operative engagement.

A suitable backstop, designed to immobilize the two meshing pinions in the limiting positions of the rocking member, may also be restrained by the control lever in the disengagement position against excessive disalignment with the teeth of the second pinion.

The above and other features of my invention will be described in detail hereinafter with reference to the accompanying drawing in which:

FIG. 1 is a somewhat diagrammatic plan view of a clockwork embodying my invention, shown in normal operating position;

FIG. 2 is a view similar to FIG. 1, showing the clockwork in a disengaged position to permit resetting of the hands of an associated timepiece; and

FIG. 3 is a detail view illustrating a modification.

The system shown in FIGS. 1 and 2 comprises an electromechanical stepping drive represented schematically by the outline l of a balance wheel which oscillates in conventional manner with electrical energy supplied by a source 100. This source may include means for electromagnetically picking up and feeding back, with intervening amplification, pulses periodically generated by the balancing wheel in the rhythm of its natural frequency. The wheel 1 has a shaft 2 carrying two

rollers

3 and 4, the former being provided with a pin 3a engaged by a bifurcate end 7 of a rocking lever 5 while the latter has a cutout 4a clearing a point 8 on that lever. A body 9 of ferromagnetic material on lever 5, which is fulcrumed on a fixed pivot 6, serves as an armature for a permanent magnet 10 having pole shoes 10a, 10b flanking the lever. The magnet helps retain the lever 5 in either of its two limiting positions, with the pole shoes 10a and 10b acting as end stops.

A projection 11 on lever 5 serves as a stepping pawl cooperating with two meshing

pinions

12 and 13, pinion 13 having a fixed axis represented by a shaft 19 and being in mesh with a larger gear 14 which is part of a conventional gear train as used in a clockwork to drive the minute and hour hands of a timepiece. The shaft 14 of gear 14 is operatively correlated with an associated seconds hand indicated diagrammatically at 14'.

Pinion 12 has a shaft 18 carried on an arm 20 of a lever L having two

further arms

21 and 22 as well as a fixed fulcrum on a pivot 23. Another lever L, is swingable about a fixed fulcrum 24 which also forms an abutment for the lever arm 21, the latter being elastically yieldable to enable a swing of the lever L in a counterclockwise sense about its fulcrum 23 with development of a restoring force as indicated by an arrow F. Lever L, has a stud 27 which normally is out of contact with lever arm 22 (FIG. I) but bears upon this arm in a position of disengagement (FIG. 2) into which the lever L, may be removed manually through the intermediary of the usual resetting pin on the winding crown of the watch, this resetting mechanism being represented in the drawing by a stem 31 engaging an extremity L, of the lever L,.

A recess 26a in lever L forms a shoulder 26 confronting a lug 15a on a disk 15, rotatable about a fixed pin 17, on which another lug serves as a backstop for the teeth of

pinions

12 and 13 when these pinions are in their meshing positions of FIG. 1.

In the normal operation of the system just described, the parts are in the position shown in FIGS. 1 and 2 with lever 5 rocking back and forth so that pawl 11 alternately strikes respective teeth of

pinions

12 and 13, driving the latter clockwise (arrow F and the former counterclockwise (arrow F with resulting intermittent rotation of gear 14 in the counterclockwise sense. Lug 16 of disk l5'reciprocates slightly in the rhythm of lever 5 and prevents a reverse motion of either pinion.

When the user wishes to reset the timepiece, he depresses the stem 31 of the release mechanism so that lever L, is swung into its alternate position (FIG. 2). Detent 25 of the end of lever arm 22 enters the gap between two teeth of gear 14 and arrests the latter in a position in which the lever 5, having just stepped the pinion l3, rests against the shoe 10a. Lever 5, upon counterclockwise rotation of disk 1 as indicated by arrow F (FIG. 1 may freely swing into its alternate position (arrow F,) but does not step the pinion 12 which has been withdrawn from its path by the counterclockwise rotation of lever L against the restoring force of its arm 21. At the same time, shoulder 26 of lever L has moved into the orbit of lug a of disk 15 whose other lug 16 is thus prevented from moving too far away from pinion 13, thereby avoiding possible jamming upon the subsequent restoration of the position of FIG. 1. The blocking of gear 14 by detent 15 also immobilizes, of course, the pinion 13 in mesh therewith. A fixed stop 30, engageable by lever L, limits the displacement of that lever in the sense of withdrawal of pinion 12 from the sweep of pawl 1 1, thereby arresting the pinion 12 in a position of incomplete separation from pinion 13 so as to prevent any clashing upon the sequent return to the position of FIG. 1.

The dial of the watch, with its minute and hour hands, has been illustrated diagrammatically at 40 in FIG. 1; the gear train driving these hands has been symbolized by a line 41 including a clutch 42 for decoupling the input element 14.

As illustrated in FIG. 3, the lever L may be replaced by a lever L pivoted on the shaft 19 of pinion 13 which permanently meshes with the gear 14 (not shown in this Figure). An extremity of lever L carries the shaft 18 of pinion 12 which is in constant close mesh with pinion 13 and which is normally maintained in the path of pawl 1 1, against a stop 35, by the force of a spring 32 coiled about shaft 19, disengagement being again achieved by a displacement of stem 31. The same stem, or an extension thereof, may carry a detent similar to projection 25 (FIGS. 1 and 2) for arresting the gear 14. A conventional pawl 33, biased toward the teeth of pinion 13 by spring 34, takes the place of backstop 16 of the preceding embodiment.

The system of FIG. 3 operates in essentially the same manner as that of FIGS. 1 and 2, except that the axial spacing of the two

pinions

12, 13 is constant.

I claim:

1. A clockwork for a timepiece having a gear train with an input element for the displacement of its minute and hour hands release means for decoupling said input element from said hands preparatorily to a resetting thereof, and a seconds hand positively coupled with said input element, comprising:

oscillatory drive means for stepping said gear train including a swingable pawl member;

a pair of counterrotating pinions meshing with each other at least in an operative position, said pinions having teeth confronting said drive means for alternate stepping by said pawl member;

a driven gear pennanently meshing with one of said pinions,

for unidirectional stepping thereby, said driven gear constituting said input element;

and control means coupled with said release means for moving the other of said pinions into an inoperative position, out of the sweep of said pawl member upon decoupling said driven gear from said minute and hour hands.

2. A clockwork as defined in claim 1, further including de tent means coupled with said control means for positively arresting said driven gear in said inoperative position of said other of said pinions.

3. A clockwork as defined in claim 2 wherein said control means comprises a lever with a first arm supporting said other of said pinions and with a second arm bearing said detent means, said lever having a fulcrum remote from the axis of said one of said pinions whereby said pinions move apart in said inoperative position.

4. A clockwork as defined in claim 3 wherein said lever is provided with yieldable stop means tending to maintain same in said operative position of said other of said pinions.

5. A clockwork as defined in claim 4 wherein said yieldable stop means comprises an elastic third arm on said lever bearing upon a fixed stop.

6. A clockwork as defined in claim 3, further comprising reciprocable backstop means engageable with the teeth of said pinions for preventing reverse rotation thereof, said lever having a formation for limiting the stroke of said backstop means upon said pinions moving apart.

7. A clockwork as defined in claim 3 wherein the mobility of said lever is limited to prevent complete separation of said pinions upon their moving a art.

8. A clockwork as defined in claim 2 wherein the axial spacing of said pinions is constant, said control means comprising a lever pivoted on the axis of said one of said pinions and carrying said other of said pinions.

9. A clockwork as defined in claim 8 wherein said pinions are provided with backstop means for preventing reverse rotation.

10. A clockwork as defined in claim 2 wherein said detent means is shaped and arranged to arrest said driven gear in a position into which it has been displaced by a stepping of said one of said pinions by said pawl member.

Claims

1. A clockwork for a timepiece having a gear train with an input element for the displacement of its minute and hour hands release means for decoupling said input element from said hands preparatorily to a resetting thereof, and a seconds hand positively coupled with said input element, comprising: oscillatory drive means for stepping said gear train including a swingable pawl member; a pair of counterrotating pinions meshing with each other At least in an operative position, said pinions having teeth confronting said drive means for alternate stepping by said pawl member; a driven gear permanently meshing with one of said pinions, for unidirectional stepping thereby, said driven gear constituting said input element; and control means coupled with said release means for moving the other of said pinions into an inoperative position out of the sweep of said pawl member upon decoupling said driven gear from said minute and hour hands.

2. A clockwork as defined in claim 1, further including detent means coupled with said control means for positively arresting said driven gear in said inoperative position of said other of said pinions.

7. A clockwork as defined in claim 3 wherein the mobility of said lever is limited to prevent complete separation of said pinions upon their moving apart.