US3541780A

US3541780A - Date-indicating wristwatch

Info

Publication number: US3541780A
Application number: US765341A
Authority: US
Inventors: Benjamin Bolle
Original assignee: Individual
Current assignee: BERNHARD FORSTER
Priority date: 1968-10-07
Filing date: 1968-10-07
Publication date: 1970-11-24
Anticipated expiration: 1987-11-24

Description

Nov. 24, 1970 B. BOLLE DATE-INDICATING WRISTWATCH 2 Sheets-Sheet 1 Filed Oct. 7. less INVENTOR Bea/Limb? Bol/e Nov. 24-, 1910 B OLLE 3,541,780

DATE-INDICATING WRISTWATCH Filed Oct. 7. 1968 I 2 Sheets-Sheet 2 uvrew rag Benjamin B0//e United States Patent US. C]. 58-58 Claims ABSTRACT OF THE DISCLOSURE A date ring in a date indicating watch carries a circular series of teeth. A drive wheel having a projecting finger rotates once in twenty-four hours. An arcuate pawl is parallel to and coplanar with the date ring and is formed with a guide slot. The pawl has at one end a hammer head and adjacent neck, and the other end has an inclined step. The hammer head engages one tooth at a time upon engagement of the finger with the inclined step. Guide elements carried by the frame engage the neck and slot. A spring opposes movement of the pawl under action of the finger and effects a return of the pawl when the finger engages the inclined step.

This invention relates to a date-advancing device in date-indicating Wristwatches.

Date-advancing devices for Wristwatches having a date ring gear, are known, which by means of a pawl is advanced by one tooth pitch every twenty-four hours. Under the action of an additional spring, the pawl advances the date indication by one day. The pawl is slidably mounted and has a nose for engaging the respective date tooth, and a stop for engagement by a finger mounted on the drive wheel. The pawl is displaced by the finger against spring action in such a manner that the pawl nose passes over the date tooth and the subsequent release of the pawl causes the same to return under spring action so that the nose of the rebounding pawl advances the date ring by one tooth and serves at the same time as a stop which limits the movement of the subsequent date tooth.

The date-advancing device according to the invention is characterized in that the pawl is arcuate and parallel and coplanar relative to the gear ring and formed with a neck and a slot which engage spaced guide pins or guide rollers so that the pawl is slidable relative to said pins or rollers and pivotally movable about one of said guide pins. The pawl has at one end an inclined step for engagement by the finger, and the pawl is formed at the other end with a hammer head, which is adapted to advance the date ring. This coplanar design is mainly desirable for a fiat design of the watch movement and enables the incorporation of the device into watches without a change of the design or size thereof. The additional spring can also be incorporated so as to be easily accessible. An angled end portion of the return spring may engage the rounded advancing head of the pawl whereas the neck of the advancing head of the pawl engages one guide pin, the second guide pin engages a guide slot on the pawl and the pivotal movement of the pawl takes place about said second guide pin.

Further details of the invention are shown in the drawing, which shows by way of example an embodiment of the invention.

FIG. 1 is an elevation showing the date-advancing device before the advancing operation and FIG. 2 is an elevation similar to FIG. 1 showing the device during the advancing operation.

The drawing indicates the main mounting plate 1 of the watch movement and the date ring 2, with which the pawl 3 cooperates. The latter has at one end an advancing head 5, which is similar to a hammer head and engageable with the date teeth, and at the other end an inclined step 6, with which the driver consisting of a finger 7 cooperates during each revolution. The drive wheel 8 is driven in known manner from the center wheel 10 by an idler wheel 9.

The pawl 3 is formed with an elongated indentation 11 defining a neck adjoining head 5, and is further formed with an elongated slot 12. The neck and slot are engaged by

spaced guide pins

13, 14 so that the pawl 3 is movable along neck and slot. The pawl 3 is pivotally movable about the pin 14 engaging the guide slot 12. An angled portion 17 of the return spring 16 engages a curved portion 15 of the advancing head 5. Another portion of the return spring 16 is disposed in an undercut recess 18 of the main mounting plate 1 of the watch movement. The advancing head 5 is formed with a bevel for engaging the teeth of the date ring 2 so that during a date correction the head 5 moving against the advancing direction tilts the pawl 3 out of engagement.

The mode of operation of the pawl 3 is apparent from FIGS. 1 and 2 of the drawing. The finger 7 engaging the inclined step 6 initially tilts the pawl 3 about the pin 14 and then displaces the pawl 3 against the action of the spring 16 to a position in which the pawl 3 is in registry with the next date tooth 4. As the drive wheel 8 continues its rotation, the finger 7 moves beyond the step 6 and the spring action returns the pawl 3 in the direction of the arrow. The subsequent rebound of the pawl 3 causes an advance of the date ring 2 by the advancing head 5. This advance is limited to one tooth pitch because the next date tooth 4 engages the advancing head 5 of the pawl 3 when the same has returned to its position of rest. In this way the instantaneous date correction, which takes place every twenty-four hours, is now completed.

What is claimed is:

1. A date-indicating wristwatch, which comprises a frame, a date ring mounted in said frame and carrying a circular series of teeth, and means for advancing said date ring by one tooth once in every twenty-four hours, said means comprising: a drive wheel mounted in said frame and arranged to perform one revolution in twentyfour hours, a finger on said drive wheel for rotation therewith, an arcuate pawl which is parallel to and coplanar with said date ring and formed with an aperture defining a guide slot, said pawl having at one end a hammer head for engaging one of said teeth at a time and at the other end an inclined step for engagement by said finger once during each revolution of said drive wheel, said pawl having an indentation defining a neck adjacent the head, said hammer being arranged to engage said one tooth upon said engagement of said finger with said inclined step, guide elements carried by said frame and respectively engaging within said neck and in said aperture to enable a displacement of said pawl along said date ring and a pivotal movement of said pawl about one of said guide elements engaged in said aperture, and spring means arranged to oppose said movement of said pawl under the action of said finger and to effect a return of said pawl when said finger has disengaged said inclined step, whereby said pawl rebounds upon said return of the pawl so as to cause said hammer head to reengage said date ring I 4 and advance it by one tooth, said pawl further serving as References Cited a stop for the next succeeding one of said teeth.

2. A wristwatch as set forth in claim 1, in which UNITED STATES PATENTS said hammer head has a rounded portion and 30821594 3/1963 Stamm et 58-48 said spring means has an angled end portion engaging 5 3421310 1/1969 Bennett ct Said rounded portion 3, 51, 1 6/ 969 Nakagawa 58-58 3. A Wristwatch as set forth in claim 1, in which FOREIGN PATENTS said hammer head has a bevelled portion for engaging 454,039 6/1968 Switzerland said teeth so as to effect said pivotal movement of said pawl away from said date teeth during the w STEPHEN J. TOMSKY Primary Examiner movement of said pawl under the action of said Spring means G. H. MILLER, JR.,,Ass1stant Examlner I 4. A wristwatch as set forth in claim 1, in which said 7 guide elements comprise guide pins. 58 4 'R- 5. A wristwatch as set forth in claim 1, in which said 15 guide elements comprise guide rollers.