US3867850A

US3867850A - Shifting mechanism and watch

Info

Publication number: US3867850A
Application number: US371961A
Authority: US
Inventors: Bernd Bechtold
Original assignee: Bernhard Foerster GmbH
Current assignee: Bernhard Foerster GmbH; BERHARD FORSTER Firma
Priority date: 1973-03-31
Filing date: 1973-06-21
Publication date: 1975-02-25
Anticipated expiration: 1992-02-25
Also published as: DE2316228B2; DE2316228C3; CH584923B5; DE2316228A1; CH772073A4

Abstract

A rotatable shifting finger and a drive means are arranged to engage the pawl of shifting mechanism to impart a pivotal movement thereto. One part of the shifting mechanism being resiliently yieldable so as to move away in response to engagement with another part.

Description

United States Patent 1191 74/142; 58/23 D, 125 B,125 R, 7

Bechtold Feb. 25, 1975 SHIFTING MECHANISM AND WATCH [56] References Cited [75] Inventor: Bernd Bechtold, Bildingen, UNITED STATES PATENTS Germany 1,997,570 4/1935 Baldwin 58/125 R 3,086,402 4/1963 Erard 74/125 [73] Ass'gnee' g zfi gs Fnrster 3,733,917 5/1973 Nikles 74/142 [22] Filed: June 21, 1 Primary Examiner-Wesley S. Ratliff, Jr. [21] App]. No.: 371,961

[57] ABSTRACT [30] Foreign Application Priority Data A rotatable shifting finger and a drive means are ar- Mar. 31, 1973 Germany 2316228 ranged to engage the pawl of shifting mechanism to impart a pivotal movement thereto. One part of the [52 US. Cl. 74 142, 58/125 R Shifting Ineehenisrn being resiliently yieldeble 89 as to 51 1111.01. F1611 27/02 move y in response to engagement with another [58] Field of Search 74/125, 125.5, 128, 129, P

9 Claims, 11 Drawing Figures SHEET 01 0F 11 PATENTEB FEB 2 5 I875 m mggraszsism $857,850

SHEET cam 11 I mgnrmzsm 3, 5

sum nuuF 11 mgmmraazsasra 57,5 59

' sum OBUF 11 PATENHD 3. 867. 850 SHEET O7UF 11 PATEHIEB P53251975 SHEET CBOF 11 PAIEMIEB 52 5 EYE PAIENTED I 3.861850 sum llUF- 11 l SHIFTING MECHANISM AND WATCH This invention relates to a shifting mechanism, particularly for shifting the hour-indicating means in wrist watches with digital indication, in which mechanism a locking pawl is provided with a locking cone and is springbiased to engage the shifting wheel (hour-shifting wheel) with said cone. Such shifting mechanism may be alternatively used, e.g., for shifting the date-indicating means in wrist watches having a date-shifting wheel.

In wrist watches with digital indication it is known to provide hour-shifting means which comprise a locking pawl that is provided with a locking cone and is springbiased to engage the hour-shifting wheel with said cone. When the hour-shifting wheel in these watches has moved to and past the apex of said cone, the wheel completes the change of the indication by a sudden movement away from said apex.

In these known watch movements, the means for setting the hands may be moved so quickly that the accelerating force, i.e., the torque of the hour-indicating disc, exceeds the restraining force of the hour-locking spring so that the hour-shifting wheel can be unintendedly advanced by one or more tooth pitches and the hour-indicating disc is thus shifted by said amount. As a result, the date indication is no longer shifted at midnight but at a preceding or succeeding hour and the watch does no longer give a correct reading but the wheels must be readjusted by a person skilled in the art. Besides, the moment of inertia of the hour-indicating disc may be changed by accelerating external shock or impact forces so that one or more unintended hour shifts result. Moreover, the spring for restraining the hour-indicating disc must not be too strong because in this case the watch movement would require an excessive driving force for a normal hour shift and even with a very strong spring an undesired shifting of the hourshifting wheel as described before cannot be reliably avoided. This is due to the fact that the pawl for restraining the hour-shifting wheel engages the latter with a locking cone which cannot entirely prevent an undesired shift even when a strong pressure is applied to the cone. I

It is an object of the invention to provide a shifting mechanism which prevents an undesired shift and which ensures that the hour shift is performed by a sudden movement not only in its end phase but the entire hour shift consists of a single, sudden movement. In a shifting mechanism for wrist watches with digital indication, comprising a locking pawl which is provided with a locking cone and is spring-biased to engage the shifting wheel (hour-shifting wheel) with said locking cone, this object is accomplished according to the invention in that a shifting pawl is provided, which extends between the teeth of the shifting wheel and extends also into the path of a shifting finger, which rotates in synchronism with the cannon and moves the shifting pawl in successive steps and against spring force past respective teeth of the shifting wheel, at least one of the parts consisting of the shifting wheel and the shifting pawl is yieldably mounted so that said shifting pawl can move past said tooth, said finger is arranged to release the shifting pawl at the end of said movement for a sudden return under said spring force to its initial position, whereby the force exerted by the locking cone of the locking pawl is overcome and a sudden movement is imparted to said shifting wheel. In its normal position, the shifting pawl extends between the teeth of the hour-shifting wheel and acts also as a locking pawl to prevent an undesired shift whereas the shifting operation performed by the shifting pawl as it springs back consists of a quick hour shift. Finally, the reading of the digital watch can be turned back.

The shifting wheel carrying the hour-indicating disc is freely rotatable on the cannon and the shifting finger is disposed under the shifting wheel and fixed to the cannon to rotate therewith. The shifting pawl extends between the teeth of the hour-shifting wheel and into the path of the underlying shifting finger.

Specifically, the shifting pawl may be mounted on a pin with an oversize hole and be spring-biased to a normal position in which the shifting pawl extends between the teeth of the shifting wheel; alternatively the shifting wheel may be mounted on the cannon with an oversize hole and be held by the spring-biased locking pawl in such a position that the shifting pawl normally extends between the teeth of the shifting wheel.

According to a further feature of the invention, the shifting pawl may be provided with a leaf spring for engaging and shifting the shifting wheel (hour-shifting wheel) and this leaf spring may be arranged to be deflected by and move past the adjacent tooth of the shifting wheel as the shifting pawl is moved by the shifting finger whereas the leaf spring shifts the shifting wheel when the shifting finger has released the shifting pawl; the leaf spring is stiffened for this purpose by engaging a shoulder 40 of the shifting pawl 36.

Embodiments of the hour-shifting means according to the invention for wrist watches with digital indication are shown diagrammatically and by way of example in the drawings, in which FIG. 1 is a partly sectional view showing a shifting mechanism according to the invention,

FIGS. 24 are elevations showing a first version of the mechanism of FIG. 1 in a normal position and during the shifting operation,

FIGS. 5 and 7 are elevations showing a second version of the mechanism of FIG. 1 in a normal position and during the shifting operation,

FIG. 8 is a partly sectional view showing another shifting mechanism, and

FIGS. 9-1l are elevations showing the shifting mechanism of FIG. 8 in its normal position and during the shifting operation.

In the first and second embodiments shown in FIGS. 1 to 7, the watch movement 1 comprises a cannon 2, on which the hour-shifting wheel 3 carrying the hourindicating disc 4 is freely rotatably mounted. Under the hour-shifting wheel, the shifting finger 5 is fixed to the cannon 2 for rotation therewith. In accordance with the sectional showing in FIG. I the hour-indicating disc 4 has an upwardly offset annular portion 6 provided with the hour numbers so that said annular portion is flush with the minute-indicating disc 7, which is mounted on the cannon 2. The sectional view shows also the second-indicating disc 8 on the second shaft 9 and the hour-indicating wheel 10 on the cannon 2 as well as the means 11 which hold the hour wheel in a predetermined axial position.

According to FIGS. 2 to 7, a locking pawl 12 is pivoted at 14 and biased by a spring 15 and provided with a locking cone 13 for engaging the teeth of the shifting wheel-3. A shifting pawl 16 is pivoted on a pin 17. A spring 18 tends to hold the shifting pawl 16 in a normal position, in which the pawl 16 extends between the teeth of the shifting wheel 3 and, as is apparent from the drawing, can cooperate with the shifting finger'S for a shifting movement. For this purpose, the shifting pawl extends into the plane of the finger 5.

In the first embodiment shown in FIGS. Z to 4 the shifting pawl 16 is mounted on the pin 17 with an oversize hole 19 for a slight radial displacement. In the second embodiment shown in FIGS. to 7 the shifting wheel.3 is mounted on the cannon 2 with an oversize hole 20 for a slight radial displacement. In these arrangements, the shifting finger 5 rotating with the cannon 2 in the direction A imparts to the shifting pawl 16 of FIG. 3 a pivotal movement, during which the pawl 16 is radially displacedby and moved past the adjacent tooth of the shifting wheel 3. In the arrangement shown in FIG. 6 the shifting finger 5 imparts a pivotal movement to the shifting pawl 16, which radially displaces the shifting wheel 3 so that the shifting pawl 16 is moved past the adjacent tooth. When the shifting finger 5 releases the shifting pawl 16, the latter springs back under spring force in both embodiments, as in shown in FIGS. 4 and 7, and imparts to the shifting wheel 3 a sudden movement corresponding to one tooth pitch whereas the force exerted by the locking cone 13 is overcome. It is apparent that in its normal position the shifting pawl 16 prevents an undesired hour shift under external influences, such as shock or impact. In the second embodiment, the shifting wheel 3 which carries the hour-indicating disc 4 may be arranged to be displaced in such a direction that the hournumber which is exposed in the window isdisplaced outwardly in the direction of the window before the shifting operation so that this displacement will not be disturbing.

In the third embodiment shown in FIGS. 8 to 11, the movement 21 comprises a cannon 22 on which the hour-shifting wheel 23 carrying the hour-indicating disc 24 is freely rotatably-mounted whereas the shifting finger 25 is disposed under the hour-indicating disc 24 and is secured to the cannon 22 for rotation therewith.

' It is apparent from thesectional view in FIG. 8 that the hour-indicting disc 24 has an upwardly offset annular portion 26, which is provided with the hour numbers and flush with the minuteindicating disc 27, which is mounted on the cannon 22. The sectional view shows also the second disc 28, which is mounted on the second shaft 29, as well as the hour wheel on the cannon 22 and the means 31 for holding the hour wheel in its axial position.

According to FIGS. 9 to 11, a locking pawl 32 is pivoted at 34 and biased by a spring 35 and provided with a locking cone 33, which engages the teeth of the shifting wheel 23. The shifting pawl 36 is pivoted on the pin 37 and biased by a spring 38 tending to hold the shifting pawl 36 in its normal position, in which the pawl extends between the teeth of the shifting wheel 23. As is apparent from the drawing, the shifting pawl can cooperate with the shifting finger 25 and for this purpose extends into the plane of said finger. In this embodiment, the shifting pawl 36 is-provided with a leaf spring 39. When the shifting pawl 36 is' moved by the shifting finger 25 past the tooth of the hour-shifting wheel 23 in the manner shown for the first or second embodiment, the leaf spring 39 is resiliently deflected by and moves past the tooth of the hour-shifting wheel 23, as is shown in FIG. 10. When the shifting finger 25 has released the shifting pawl 36 so that the latter springs back, the leaf 1. In a shifting mechanism comprising a locking pawl provided with a locking cone and hour shifting wheel with teeth with said lockingpawl being spring biased to engage said teeth, the improvement comprising the inclusion of:

a pivoted shifting pawl adapted to engage said teeth,

a second spring means biasing said shifting pawl toward an initial angular position,

a rotatably mounted shifting finger, and driving means for rotating said shifting finger, said shifting finger being arranged to temporarily engage said shifting pawl and impart a pivotal movement thereto from said initial angular position during a rotational movement of said shifting finger through a predetermined angular range, i

said shifting pawl being arranged to engage one of said teeth during said pivotal movement,

at least one of the parts consisting of said wheel and shifting pawl being resiliently yieldable so as to move away from the other of said parts in response to the engagement of said shifting pawl with said one tooth during said pivotal movement so that said shifting pawl can move past said one tooth during said pivotal movement,

the arrangement being such that said shifting finger releases said shifting pawl when the same has been pivotally moved past said one tooth and that in response to the release of said shifting pawl by said shifting finger said yieldable part springs back toward the other of said two parts and said shifting pawl springs back to said initial angular position under the action of said second spring means so as to engage said'one tooth and to overcome said restraining force and impart to said wheel a predetermined sudden angular movement.

2. A shifting mechanism as set forth in claim 1, in which said yieldably mounted part -'is said shifting wheel.

3. A shifting mechanism as set forth in claim 1, in which said yieldably mounted part is said shifting pawl.

4. A shifting mechanism as set forth in claim 1, in which said shifting pawl has an oversize hole and said hole is pivotally and radially displaceably mounted on a pivot pin.

5. A shifting mechanism as set forth in claim 1, in which said shifting wheel has an oversize hole and said hole is pivotally and radially displaceably mounted on a pivot member.

6. A shifting mechanism as set forth in claim 1, in which said shifting wheel and said shifting finger are mounted on a common axis and extend in respective axially spaced planes and said shifting pawl extends in both said planes.

7. A shifting mechanism as set forth in claim 1, in which said locking pawl is pivotally mounted, and

said first spring means engage said locking pawl on the side opposite to said wheel and tend to move said locking pawl into a position in which said locking cone extends between two adjacent ones of said teeth.

8. A shifting mechanism as set forth in claim 1, in which said first spring means are arranged to urge said locking pawl into a position in which said locking cone holds said wheel in such an angular position that said shifting pawl when in said initial angular position extends between two adjacent ones of said teeth.

9. In a shifting mechanism comprising a locking pawl provided with a locking cone and hour shifting wheel with teeth with said locking pawl being spring biased to engage said teeth, the improvement comprising the in clusion of:

a pivoted shifting pawl adapted to engage said teeth,

a rotatably mounted shifting finger, and driving means for rotating said shifting finger, said shifting finger being arranged to temporarily engage said shifting pawl and impart a pivotal movement thereto from said initial angular position during a rotational movement of said shifting finger through a predetermined angular range,

said shifting pawl being arranged to engage one of said teeth during said pivotal movement, with said shifting pawl having a free end portion adjacent said wheel with a leaf spring moveably attached thereupon and leaving a tip extending from said free end with said spring engaging one said tooth during said pivoted movement said spring adapted to be latterally deflected from said free end in response to said engagement so as to move past said tooth and to return to said free end portion when said shifting finger has released said shifting pawl.

Claims

1. In a shifting mechanism comprising a locking pawl provided with a locking cone and hour shifting wheel with teeth with said locking pawl being spring biased to engage said teeth, the improvement comprising the inclusion of: a pivoted shifting pawl adapted to engage said teeth, a second spring means biasing said shifting pawl toward an initial angular position, a rotatably mounted shifting finger, and driving means for rotating said shifting finger, said shifting finger being arranged to temporarily engage said shifting pawl and imPart a pivotal movement thereto from said initial angular position during a rotational movement of said shifting finger through a predetermined angular range, said shifting pawl being arranged to engage one of said teeth during said pivotal movement, at least one of the parts consisting of said wheel and shifting pawl being resiliently yieldable so as to move away from the other of said parts in response to the engagement of said shifting pawl with said one tooth during said pivotal movement so that said shifting pawl can move past said one tooth during said pivotal movement, the arrangement being such that said shifting finger releases said shifting pawl when the same has been pivotally moved past said one tooth and that in response to the release of said shifting pawl by said shifting finger said yieldable part springs back toward the other of said two parts and said shifting pawl springs back to said initial angular position under the action of said second spring means so as to engage said one tooth and to overcome said restraining force and impart to said wheel a predetermined sudden angular movement.

2. A shifting mechanism as set forth in claim 1, in which said yieldably mounted part is said shifting wheel.

7. A shifting mechanism as set forth in claim 1, in which said locking pawl is pivotally mounted, and said first spring means engage said locking pawl on the side opposite to said wheel and tend to move said locking pawl into a position in which said locking cone extends between two adjacent ones of said teeth.

9. In a shifting mechanism comprising a locking pawl provided with a locking cone and hour shifting wheel with teeth with said locking pawl being spring biased to engage said teeth, the improvement comprising the inclusion of: a pivoted shifting pawl adapted to engage said teeth, a second spring means biasing said shifting pawl toward an initial angular position, a rotatably mounted shifting finger, and driving means for rotating said shifting finger, said shifting finger being arranged to temporarily engage said shifting pawl and impart a pivotal movement thereto from said initial angular position during a rotational movement of said shifting finger through a predetermined angular range, said shifting pawl being arranged to engage one of said teeth during said pivotal movement, with said shifting pawl having a free end portion adjacent said wheel with a leaf spring moveably attached thereupon and leaving a tip extending from said free end with said spring engaging one said tooth during said pivoted movement said spring adapted to be latterally deflected from said free end in response to said engagement so as to move past said tooth and to return to said free end portion when said shifting finger has released said shifting pawl.