US3129554A

US3129554A - Electric timekeeper

Info

Publication number: US3129554A
Application number: US176069A
Authority: US
Inventors: Yasukawa Hideaki
Original assignee: Suwa Seikosha KK
Current assignee: Suwa Seikosha KK
Priority date: 1961-03-06
Filing date: 1962-02-27
Publication date: 1964-04-21
Anticipated expiration: 1981-04-21

Description

April 21, 1964 HIDEAKI YASUKAWA 3,129,554

ELECTRIC TIMEKEEPER Filed Aug. 27, 1962 2 Sheets-Sheet 1 Prior Ari April 21, 1964' HIDEAKI YASUKAWA 3,129,554

ELECTRIC TIMEKEEPER Filed Aug. 27, 1 962 2 Sheets-Sheet 2 11 fie United States Patent Ofitice 3,129,554 Patented Apr. 21, 1964 3,129,554 ELECTRIC TIMEKEEPER Hideaki Yasukawa, Suwa-shi, Nagano-ken, Japan, as-

signor to Kabushiki Kaisha Suwa Seikosha, Suwa-shr,

Nagano-ken, Japan, a joint-stock company of Japan Filed Feb. 27, 1962, Ser. No. 176,069 Claims priority, application Japan Mar. 6, 1961 4 Claims. ((11. 58-23) This invention relates to electric timekeepers, and more particularly it relates to an improvement in electric timekeepers whereby inconveniences, defective operation, and breakage at the time of setting of the timekeeper indicating hands are effectively prevented.

More specifically, this invention relates to battery-powered timekeepers (particularly battery-powered watches and clocks) of the type wherein a driving pawl is fixed by way of a spring material to an oscillating member which is driven (excited) electrically, and the driving pawl, which oscillates together with the oscillating member and undergoes reciprocating motion, imparts rotation in one direction to a ratchet wheel, whereby the indication mechanism (or mechanism operating the time indicating hands) is driven.

Electric timekeepers of this type are capable of driving, with high efficiency, the indication mechanism by means of the oscillating member which oscillates at a constant frequency to become the time standard of the tirnekeeper. Accordingly, this type of electric timekeeper has been utilized widely for known kinds of hanging clocks and also for recent watches.

However, if, at the time of setting the timekeeper hands, the friction stop of the center wheel shaft and the cannon pinion (minute hand shaft) is excessively effective, the second hand will rotate at an extremely high speed when the timekeeper is set to the correct time by moving the hour and minute hands. Consequently, it will be difiicult to set the timekeeper to the correct second. Furthermore, since the ratchet wheel rotates at an even higher speed than the second hand, there has been the danger of causing wear and damage to the teeth of the ratchet wheel.

In order to overcome the above difficulty, it has been the conventional practice to resort to such measures as adjusting the friction stop of the center wheel shaft and the cannon pinion to operate in a loose manner, or cautioning the user against reverse rotation during time setting. In the case of the former measure, however, since the friction stop is loose, defective rotation of the minute hand often results. That is, in spite of the correct operation of the mechanism, the indication of the minute hand is unstable or the minute hand does not move. As a result, the value of the timekeeper as a product is greatly lowered. Furthermore, the suitable adjustment of this friction stop is difficult and requires a high degree of skill because of the narrowness of the range of suitability.

It is a general object of the present invention to eliminate the above-described difiiculties and inconveniences inherent in conventional electric timekeepers of this type.

Said object and the other objects of this invention have been attained by an improvement comprising means to disengage, at the time of time setting of the timepiece, the said driving pawl and a click for preventing reverse rotation from the said ratchet wheel and means to lock one part of the said wheel train at the same time.

According to the said improvement, it becomes possible to increase the tolerance of the strength of the friction stop between the cannon pinion and center wheel shaft. The reason for locking one part of the wheel train as well as disengaging the driving pawl and a click for preventing reverse rotation from the ratchet wheel is as follows:

Because of the fact that the rotation ratio between the ratchet wheel and one part of the wheel train to be locked at the time setting is very large, when minute hand and time hand are to be reversely rotated there occurs an apprehension such that the driving pawl and click for preventing reverse rotation are impaired by the ratchet owing to slight relaxation of the bearing of the wheel train and mechanical deformation of the means for locking one part of the wheel train.

The nature and details of the invention will be more apparent by reference to the following description taken in conjunction with the accompanying drawings in which like parts are designated by like reference numerals and characters, and in which:

FIG. 1 is a schematic diagram showing the constructional arrangement of a conventional electric timekeeper mechanism with which the embodiment of the present invention will be compared;

FIG. 2 is a schematic diagram showing the constructional arrangement of one embodiment of the present invention;

FIGS. 3, 4, and 5 are schematic views showing the details of the important parts of the embodiment shown in FIG. 2;

FIG. 6 is a schematic diagram showing the embodiment of FIG. 2 in a different operational state; and

FIGS. 7, 8, and 9 are schematic views for a description of the functions of the important parts shown in FIG. 6.

Referring to the drawings, the embodiments shown apply to wrist watches and are depicted in a simplified schematic manner for convenience in description, but it is to be understood that they have different configurations and arrangements in practical application.

In the conventional system shown in FIG. 1, when the winding button 1 is placed in the setting state and the time is to be set, one revolution of the minute hand M is accompanied by 60 revolutions of the second hand S and, for example, as high as 1,000 revolutions of the ratchet wheel 15. In ordinary time setting, since the minuted hand is turned one revolution in a few seconds, the second hand is caused to rotate at about 600 revolutions per minute (r.p.m.), and the ratchet wheel to rotate at a speed as high as 10,000 r.p.m. Consequently, the driving pawl 17a. and the click 18a for preventing reverse rotation of the ratchet wheel 15 are caused to undergo a vibration of 1,000,000 or more cycles per minute.

The parts designated in FIG. 1 by the reference numerals 2-44, 17b, 18b and 31 Will be described in conjunction with FIG. 2.

One embodiment of this invention in its normal time indication state, or go state, is indicated in FIG. 2, in which a winding stem 2 is fixed to and rotates integrally with the winding button 1 and is provided with an annular groove 2a with which ends of a setting lever 3 and a lever 19 are engaged. The winding stem 2 is provided also with a sliding pinion 2b which is engaged with the winding stem 2 in such a manner as to be freely slidable thereon in the axial direction thereof but to rotate together with the wind stem 2. This sliding pinion 2b has an annular groove 20, in which one end of a clutch lever 4 is engaged. The position of this clutch lever is controlled by the setting lever 3. This setting lever 3 is pivoted by a shaft 3a which is fixed to a base plate. The sliding pinion 211 further has a gear 5 fixed thereto to rotate integrally therewith. During normal time indication or go operation, the gear 5 is separated from the minute wheel 6 of the gear train, as indicated in FIG. 2.

Time regulation and driving power is provided through an oscillating member 21 the oscillation of which is maintained electrically. This oscillating member 21 is a tuning fork, a tuning bar, or a tuning rod, and drives a spring 17b, provided thereon at a suitable position, in reciprocating motion substantially in the longitudinal direction of the spring 17b. A pawl 17a fixed to the extreme end of the spring 17b is thereby caused to undergo reciprocating motion and drive a ratchet wheel 15 in one rotational direction.

The ratchet wheel 15 is prevented from rotating in the reverse direction by a click 18a fixed to the end of a spring 1817. The regulated driving power thus imparted by the pawl 17a to the ratchet wheel 15 is transmitted to the minute hand M, hour hand T, and second hand S by way of the wheel train in the order of: a ratchet wheel pinion 16; an idler wheel 13 and its pinion 14; a second wheel 11 and its pinion 12; a third Wheel 9 and its pinion 10; a center wheel 7 and its pinion 8; a minute wheel 6 and its pinion (not shown); an hour wheel (not shown); and an hour hand shaft. The cannon pinion of the minute hand shaft is held by friction to the center wheel shaft, but this feature is not shown.

The lever 19 which is engaged with the groove 2a of the winding stem 2 is rotatable about a pivot 19c and is provided with lugs 19a and 19b, which are so positioned thereon as to be in the engageable vicinity of springs 17]) and 18b, respectively, for engagement as will be described hereinafter. A spring rod 20 is fixed to the lever 19 near its pivot 19c and rotates together with the lever 19. This spring rod 20 is provided at its free end With a tooth 20a which, in the state indicated in FIG. 2, is near but not in contact with the second wheel 11.

When the timekeeper is in its normal time indication or go state as shown in FIG. 2, the relative positions of the springs 17b and 18b and the lugs 19a and 1912 are as indicated in FIG. 3, and the relative positions of the second wheel 11 and the spring rod 20 and its tooth 20a are as indicated in FIG. 4, which shows a view taken perpendicularly to the axis of the second wheel, and FIG. 5, which is an enlarged, partial view showing teeth 11a, 11d, of the second wheel 11.

Next, the operation of setting the indicating hands will now be described with reference to FIGS. 6, 7, 8, and 9, wherein the time-setting state is indicated. When the winding button 1 is pulled outwardly, the various parts designated by 1, 2, 2b, 3, 4, 5, 19, and 20 shift or rotate in the directions indicated by their respective arrows in FIG. 6. Accordingly, the gear 5 meshes with the minute wheel 6, and the lugs 19a and 19b engage with the springs 17b and 18b, respectively, and disengage the pawl 17a and the click 18a at the ends of these springs from the ratchet wheel 15. Holding pawl 18a is lifted from engagement with ratchet wheel by lug 1% on lever 19 to allow slight reverse motion of ratchet wheel 15 which may occur when tooth 20a on spring rod 20 enters into one of the spaces between teeth 11a- 11d of second wheel 11. Simultaneously, the second wheel 11 is locked by the spring rod 20 and its tooth 20a, whereby the wheel train of the timekeeper stops. Then, since the second hand S can be set (stopped) at any position, second setting becomes possible.

The parts of the lugs 19a and 19b which engage with the springs 17b and 18b are made amply smooth so that, in the above-described state wherein the lug 19a is contacting the spring 1711 and keeping the pawl 17a away from the ratchet wheel 15, the oscillating member 21 can oscillate in a stable manner.

By tightening the friction stop of the shaft of the center wheel 7 and the cannon pinion to the extent preventing slippage, setting the hands at any time becomes possible. By pressing the winding button 1 inwardly after the hands have been set, the timekeeper system is placed in the state indicated in FIG. 2, and the time indication or go operation is again started. In this case, if the oscillation of the oscillating member were to be stopped during the setting operation, the timekeeping operation would not start until the oscillation of the oscillating member has reached its normal operating amplitude after the winding button has been pressed inwardly. Consequently, it would not be possible to set the timekeeper to any desired time. In the timekeeper according to this invention, however, since the oscillating member is caused to continue its oscillation during the setting operation, the timekeeping operation starts promptly when the winding button is pressed inwardly.

The state of engagement of the lugs 19a and 19b with springs 17b and 1812, respectively, when the timekeeper is in the setting state of FIG. 6 is indicated diagrammatically in FIG. 7. The engagement of the tooth 20a of the spring rod 20 with the fourth wheel 11 is indicated in FIGS. 8 and 9.

By the constructional arrangement as described above, the timekeeper embodying the present invention is freed of the afore-described disadvantages inherent in conventional timekeepers of this type, wherefore its merchandise value is greatly increased. Moreover, since fine adjustment of the friction stop mechanism is not necessary, the present timekeeper is advantageous from the manufacturing viewpoint.

Although this invention has been described with respect to a particular embodiment thereof, it is not to be so limited as changes and modifications may be made therein which are within the full intended scope of the invention, as defined by the appended claims.

What is claimed is:

1. In an electric timekeeper of the type having an oscillating member which is electrically oscillated and provided with a driving pawl which drives a ratchet Wheel which, in turn, drives a wheel train for time indication operation; an improvement comprising a winding stem reciprocably mounted on the timekeeper, means to normally prevent retrograde movement of the ratchet Wheel, lever means pivotally mounted on the timekeeper and having one end thereof in engagement with said winding stem, lock means on the other end of said lever means, said winding stem adapted to be drawn out- 'wardly relative to the timekeeper to pivot said lever means and cause engagement of said lock means with a part of the wheel train to lock the same, and means on said lever intermediate the ends thereof to effect disengagement of the driving pawl from the ratchet wheel and disengagement from the ratchet wheel of the means which normally prevents retrograde movement of the same.

2. In an electric timekeeper as defined in claim 1, wherein said lock means on said lever comprises a spring fixed at one end to said lever, and a tooth mounted on the free end of said spring which effects the lock of the part of the wheel train into which the tooth is brought into engagement.

3. In an electric timekeeper as defined in claim 1, wherein said means to normally prevent retrograde movemember adapted to freely oscillate when the driving pawl is disengaged from the ratchet wheel.

References Cited in the file of this patent UNITED STATES PATENTS 2,713,764 St. Vaulry July 26, 1955 2,858,664 I-leimann Nov. 4, 1958 2,865,163 Ensign Dec. 23, 1958 3,057,147 Hetzel Oct. 9, 1962

Claims

1. IN AN ELECTRIC TIMEKEEPER OF THE TYPE HAVING AN OSCILLATING MEMBER WHICH IS ELECTRICALLY OSCILLATED AND PROVIDED WITH A DRIVING PAWL WHICH DRIVES A RATCHET WHEEL WHICH, IN TURN, DRIVES A WHEEL TRAIN FOR TIME INDICATION OPERATION; AN IMPROVEMENT COMPRISING A WINDING STEM RECIPROCABLY MOUNTED ON THE TIMEKEEPER, MEANS TO NORMALLY PREVENT RETROGRADE MOVEMENT OF THE RATCHET WHEEL, LEVER MEANS PIVOTALLY MOUNTED ON THE TIMEKEEPER AND HAVING ONE END THEREOF IN ENGAGEMENT WITH SAID WINDING STEM, LOCK MEANS ON THE OTHER END OF SAID LEVER MEANS, SAID WINDING STEM ADAPTED TO BE DRAWN OUTWARDLY RELATIVE TO THE TIMEKEEPER TO PIVOT SAID LEVER MEANS AND CAUSE ENGAGEMENT OF SAID LOCK MEANS WITH A PART OF THE WHEEL TRAIN TO LOCK THE SAME, AND MEANS ON SAID LEVER INTERMEDIATE THE ENDS THEREOF TO EFFECT DISENGAGEMENT OF THE DRIVING PAWL FROM THE RATCHET WHEEL AND DISENGAGEMENT FROM THE RATCHET WHEEL OF THE MEANS WHICH NORMALLY PREVENTS RETROGRADE MOVEMENT OF THE SAME.