US3628323A

US3628323A - Miniaturized electronic watch

Info

Publication number: US3628323A
Application number: US2819A
Authority: US
Inventors: Werner R Baumgartner; Hans P Kaufman
Original assignee: Bulova Watch Co Inc
Current assignee: Bulova Watch Co Inc
Priority date: 1969-02-06
Filing date: 1970-01-14
Publication date: 1971-12-21
Anticipated expiration: 1988-12-21
Also published as: HK52776A; NL7001402A; FR2030345B1; JPS4840112B1; CH179869A4; FR2030345A1; DE2003045A1; GB1269885A; CH556568A; DE2003045B2

Abstract

A miniaturized electronic watch in which a tuning fork resonator is sustained in vibration by a transistorized drive circuit energized by a single power cell, the vibratory action being converted into rotary motion to operate a dial train which turns the hands of the watch. The watch movement includes a pillar plate below which the power cell is so positioned that its periphery coincides at one point with the border of the plate, the body of the cell extending to or beyond the geometrical axis of the hands, which axis is normal to the plate. The tuning fork is disposed to one side of the cell below the plate, whereas the dial train is mounted above the cell to provide a highly compact layout.

Description

United States Patent [72] Inventors Werner R. Baumgartner [56] References Cited UNITED STATES PATENTS gjl zg fi 2,900,786 8/1959 Hetzel 58/23 [2]] pp No 2,819 3,l 84,910 5/1965 Laviolette 58/28 3,469 389 9/1969 Nakai et al 58/23 [22] Filed Jan. 14, 1970 [45] Patented Dec. 21, 1971 Primary Examiner-Richard B. Wilkinson [73] Assignee Bulova Watch Company Inc. Assistant ExaminerEdith C. Simmons New York, N.Y. Attorney-Michael Ebert [32] Priority Feb. 6, 1969 [3 3] Switzerland [31] 1798/69 ABSTRACT: A miniaturized electronic watch in which a tuning fork resonator is sustained in vibration by a transistorized v drive circuit energized by a single power cell, the vibratory acl5 MINIATURIZEDELECTRONIC WATCH tion being converted into rotary motion to operate a dial train 5 Claims, 3 Drawing Fig which turns the hands of the watch. The watch movement in- 52 U.S.Cl 58/23 BA cludes a Plate which the Power is 5 8 /23 tioned that its periphery coincides at one point with the border [51] GMc 3/00 of the plate, the body of the cell extending to or beyond the [50] 58/23 50 geometrical axis of the hands, which axis is normal to the 6 plate. The tuning fork is disposed to one side ofthe cell below the plate, whereas the dial train is mounted above the cell to provide a highly compact layout.

Z5 5 3 WA 32 a9 Ill-H Z2 MM. l7 1 ll l) 178 ll Ill 4i i p \T Z4- 57 r" i farm/c I Zoe g 36 11150184) l 4o L l as PATENTEB UECZI I97! SHEET 1 BF 2 INVENTO s This invention'relates generally to battery-operated electronic timepieces, and more particularly to a miniaturized electronic watch including a tuning fork resonator whose vibrations are converted into rotary motion for operating dial pointers.

In electronic timepieces of the type disclosed in US. Pat. No. Re.26,322, a battery-energized transistor drive circuit acts to sustain the vibratory motion of a tuning fork. This motion is transferred by a pawl and ratchet mechanism to a rotary movement including a gear train and dial pointers or hands.

In tuning fork electronic watches of the type heretofore known, the structural arrangement has been such as to preclude a reduction in the diameter and other dimensions of the watch movement to a degree making it possible to house the movement within a ladies watch case. Though such watches have been made in relatively large models having masculine appealyit has not hitherto been feasible to miniaturize the dimensions to a point rendering the watch acceptable to ladies.

The main obstacle to a further reduction in the dimensions of an electronic timepiece of the tuning fork type, is the power cell. This single-cell battery, which is round and buttonlike, occupies a relatively large portion of the useful volume of a watch movement. In the conventional layout, the power cell is laterally displaced from the dial train, as a consequence of which a watch movement with a commercially available type of power cell has a diameter of at least 25 millimeters. This diameter is beyond the limits acceptable in ladies-model watches.

SUMMARY or INVENTION In view of the foregoing, it is the main object of this invention to provide a miniaturized electronic watch movement which may be housed in a relatively small case and is, therefore, acceptable in lades models or for other applications in which small size is a desideratum.

More specifically, it is an object of the invention to provide a layout for an electronic watch of the tuning fork type, in which the single power cell is disposed below the pillar plate with its periphery coincident to the border of the plate at at least one point, the fork being also disposed below the plate in side-by-side relation to the cell, whereas the dial train for turning the hands is mounted above the cell, to afford a highly compact structure.

A significant feature of the invention is that the layout of the dial train, power cell, tuning fork, and the associated electronic assembly, is such as to make possible a movement whose diameter is less than 20 millimeters, such dimensions being suitable for ladiesmodels.

Briefly stated, these objects are accomplished in a tuning fork electronic watch movement in which the single buttonlike power cell for energizing the electronic drive circuit is placed below the pillar plate with at least one point on its periphery coincident with the border of the plate, the body of the cell extending beyond the geometrical center of the hands. The tuning fork is disposed in side-by-side relationship to the cell below the plate and is operatively coupled to the dial train for turning the hands, which dial train is mounted above the cell.

OUTLI E or DRAWING For a better understanding of the invention, as well asother objects and further features thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawing, wherein:

FIG. 1 is a schematic view of an electronic watch in accordance with the invention as viewed from the dial side, with the dial, pillar plate, and case omitted to facilitate an understanding of the invention;

FIG. .2 is a transverse section taken in the plane indicated by line 2-2 in FIG. 1; and

FIG. 3 is a schematic diagram of the electronic circuit of the watch.

DETAILED DESCRIPTION OF INVENTION Referring now to the drawing, a miniaturized watch movement in accordance with the invention includes a circular pillar plate 10, above which is mounted a watch dial 11. The movement fits within a case (not shown). The purpose of the invention is to provide a movement of small diameter adapted to fit within a ladies model case of 20 millimeters or less.

Disposed below pillar plate 10 is a buttonlike, round power cell 12 whose flat top and bottom surfaces are parallel to the plane of pillar plate 10. Cell 12 is tangentially disposed with respect to the border of pillar plate 11, so that point 13 on the circumference of the cell is substantially in line with the border. Depending on the shape of the power cell relative to the pillar plate, more than one coincidence point is possible.

The seconds, minute and hour hands indicated diagrammatically by lines S, M and H, are mounted respectively on arbor 14, cannon 15, and tube 16, respectively, which are coaxially arranged. The axis of arbor 14, which is the geometrical axis X of the hands, coincides with the center of pillar plate 10. The diameter of cell 12 is somewhat greater than the radius of the pillar plate; hence the body of the cell extends well beyond the geometrical axis X of the hands. Therefore, in the embodiment illustrated, the axis X passes through the power cell. In other instances, thecell may come quite close to the axis, or go only slightly beyond it.

The electronic watch includes a tuning fork, generally designated by numeral 17, having two

tines

17A and 17B, and a reentrant mounting stem 18 which is attached to the underside of the pillar plate by screws 19. The fork is positioned in side-by-side relationship to cell 12, the tines lying in a common plane which is parallel to the top and bottom surfaces of the cell.

At the free ends of

tines

17A and 17B are attached permanent magnets 20A and 208 which cooperate with a stationary pancake-shaped coil 21 having sensing and drive windings 21A and 218 (FIG. 3), the magnetic flux in the airgap of the magnets being perpendicular to the plane of the coil. Coil 21 is supported from a projection 22 formed on a plastic module 23 which houses the electronic assembly, generally designated by numeral 24.

This assembly, as best seen in FIG. 3, is constituted by a transistor T and a resistance capacitance network RC which is associated with the sensing and drive windings 21A and 218. The manner in which the circuit acts to sustain the tuning fork in vibration is explained in US. Pat. No. 2,971,323, and will, therefore, not be repeated herein.

It will be seen that the outer side of module 23 is convex to conform to the corresponding curvature of the border of the pillar plate on which it is mounted, whereas the inner side is concave to conform to the curvature of cell 12, while the profile of the upper side follows that of the tuning fork. Thus the shape of module 23 permits optimum use of the space between the fork, the cell, and the periphery of the movement.

An index finger 25 is attached to tine 17A, the finger 25 having a jewelled tip which engages the teeth of an index wheel 26. A pawl (not shown) cooperates with the wheel to prevent retrograde motion thereof. The pinion 27 of index wheel 26 meshes with the teeth of a wheel 28 whose pinion 29 drives a wheel 30. The pinion 31 of wheel 30 drives an intermediate wheel 32, which in turn drives a pinion 33 mounted on the lower end of the arbor 14 for turning the seconds hand S.

On the arbor 35 of intermediate wheel 32, is attached a pinion 34 which drives wheel 36.- A friction clutch (not shown) is interposed between wheel 36 and cannon 15. Cannon 15 is provided with a pinion 37 which meshes with minute wheel 38, which, by means of pinion 39, drives hour wheel 40 mounted on tube 16.

It will be seen that all dial train elements supporting hands S, M and H, are disposed above power cell 12. As seen from the backside of the movement, all of these parts, including minute wheel 38, are hidden by cell 12. Thus ,the cell, instead of being laterally displaced from the dial train elements, as in the conventional electronic watch arrangement, are disposed thereover, making possible a substantial reduction in the diameter of the movement.

While there has been shown a preferred embodiment of a miniaturized electronic watch in accordance with the invention, it will be appreciated that changes and modifications may be made within the scope of the invention For example, other parts of the wheel train may be placed on top of the cell in addition to those shown. This depends on the shape of the resonator, which is not limited to the tuning fork shown, and on the arrangement of the other electronic and mechanical components.

What we claim is:

l. A miniaturized electronic timepiece comprising:

A. a pillar plate having a dial thereover;

B. timing hands turnable on said dial with respect to a geometrical axis passing through the center of said plate,

C. a button-shaped, single power cell disposed below said plate at a position in which one point on the periphery of said cell substantially coincides with the border of said plate, the body of the cell extending at least to said axis, the flat top surface of said cell being parallel to said plate, D. a mechanical resonator serving as a frequency standard, said resonator being constituted by a tuning fork sustained in vibration by an electronic drive circuit energized by said cell, the fork being disposed below said plate to one side of said cell and having a pair of tines which lie in a plane parallel to the top and bottom surfaces of said cell, and

E. means to convert the vibrations of said resonator to rotary motion for turning said hands, said means including a dial train operatively coupled to said hands and disposed above the plane defined by the top surface of said cell.

2. A timepiece as set forth in claim 1, wherein said timing hands are constituted by seconds, minute and hour hands, the seconds hand being supported on an arbor lying along said geometrical axis, the minute hand being supported on a cannon coaxially disposed with respect to said arbor, said hour hand being supported on a tube concentric with said cannon, said arbor being operated by a pinion attached to the end thereof, which pinion is hidden by the cell when looking at the movement from the side opposing the dial.

3. A timepiece as set forth in claim 2, wherein said cannon and tube are also hidden by the cell.

4. A timepiece as set forth in claim 3, wherein said cannon is engaged by a minute wheel which is disposed above the plane defined by the top surface of said cell and is hidden by said cell when the movement is viewed from the side opposing the dial.

5. A timepiece as set forth in claim 3, wherein the com ponents forming said electronic drive circuit are contained in a plastic module disposed between the border of said plate, the periphery of the cell, and one tine of the fork, the outer side of the module being curved to conform to the curvature of said border, the inner side of the module being curved to conform to the curvature of said cell.

Claims

1. A miniaturized electronic timepiece comprising: A. a pillar plate having a dial thereover; B. timing hands turnable on said dial with respect to a geometrical axis passing through the center of said plate, C. a button-shaped, single power cell disposed below said plate at a position in which one point on the periphery of said cell substantially coincides with the border of said plate, the body of the cell extending at least to said axis, the flat top surface of said cell being parallel to said plate, D. a mechanical resonator serving as a frequency standard, said resonator being constituted by a tuning fork sustained in vibration by an electronic drive circuit energized by said cell, the fork being disposed below said plate to one side of said cell and having a pair of tines which lie in a plane parallel to the top and bottom surfaces of said cell, and E. means to convert the vibrations of said resonator to rotary motion for turning said hands, said means including a dial train operatively coupled to said hands and disposed above the plane defined by the top surface of said cell.

5. A timepiece as set forth in claim 3, wherein the components forming said electronic drive circuit are contained in a plastic module disposed between the border of said plate, the periphery of the cell, and one tine of the fork, the outer side of the module being curved to conform to the curvature of said border, the inner side of the module being curved to conform to the curvature of said cell.