US1343798A - Pin-anchor escapement for timepieces - Google Patents

Description

T. TODA.

PIN ANCHOR ESOAPEIIENT FOR TIIIEHECES.

APPLICATION FILED u0v 14. me.

1,343,798. PatentedJune 15, 1920.

UNITED STATES PATENT OFFICE.

TOMOKICHI TODA, OF KAIJO, CHOSEN, ASSIGNOR 0F ONE-HALF T0 TOMOKICHI TAKATA, 0F NAGOYA CITY, JAPAN, AND

OFIWATE, JAPAN.

ONE-HALF T0 HANSUKE GUNJI,

PIN-ANCHOR ESCAPEMENT FOR 'IIMEPIECES.

Specification of Letters Patent. Patented J e 15, 1920,

Application filed November 14, 1918. Serial No. 262,627.

To all whom it may concern Be it known that I, TOMOKIGHI ToDA, a subject of the Emperor of Japan, and resident of 116 Kitahommachi, Kaijo, Keiki Do, Chosen, Empire of Japan, have invented certain new and useful Improvements in Pin-Anchor Escapements for Timepieces, of which the following is a specification.

My invention relates to an improvement in the so-called pin-anchor escapement hitherto in use, wherein a lever known as an anchor is arranged adjacent to an escapement-wheel tending to rotate in a definite direction through the force of a winding spring and the catching and releasing of the escapement-wheel are performed alternately in accordance with the oscillation of the said lever by means of pins fitted to the arm of the lever, and consists in providing two gear-wheels, instead of one as has been the case hitherto, and in making special arrangements accordingly toattain the objects in View, each of the said gear-wheels being provided with teeth so constructed that the side of each tooth facing the direction of rotation is curved into an arc-shape to conform with the path of oscillation of a particular engaging pin, and a pin being fitted to each of the two arms of the anchor to engage with a corresponding gear wheel.

The prime object of my invention is to provide an improved pin-anchor escapement capable of absolutely eliminating recoils'of the gearwvheel, incident to pin-anchor escapements hitherto in existence, making the escaping action smooth, maintaining constant moving conditions irrespective of the strength of the winding spring, and increasing durability of running of the mechanism.

Other objects and advantages to be derived from the use of my invention willappear in the following detailed description and the claims, taken with an inspection of the accompanying drawings, in which:

Figure 1 is a side elevational view of the pin-anchor escapement embodying my invention; Fig. 2 is a front elevational view of the principal parts thereof; and, Figs. 3 and 4 are, respectively, magnified views of part of the same, showing the manner of escape action.

Throughout the several views, similar characters for reference designate like and corresponding parts.

An axle 2 is mounted on a framework 1l, front and rear gear-wheels 3 and 1 are attached to the axle 2, an axle '5 is arranged above the same, a lever or the so-called anchor 6 is rigidly fixed in a position intermediate the said two gear-wheels, pins 7 and 8 are provided at the two opposite ends of the lever so as to act on the gear-Wheels 3 and 4, respectively, an arm 9 with its farther end forked is attached to the axle 5 to face on a disk 12 fitted to the axle 11 of a balance 10, and a hair-spring 13 is arranged on the head of the axle 11, all these parts being so arranged and constructed that the forked end of the arm 9 presses a pin 14 provided on the disk 1% and turns the balance 10 when the said arm oscillates, and energy or force stored in the hair-spring 13 reverses the same, which makes it possible to maintain periodically reciprocating rotations of the balance. The arm 9 is limited in its movement by pins 15 and 15 firmly set on the framework, and a pin 16 attached to the farther end is made to come into contact with the periphery of the disk 12 to prevent its unnecessary motion and to allow the arm to oscillate only when it has engaged with a groove or notch 17 provided at part of the disk.

The axle 2 of the gear-wheels 3 and 4 is connected with the winding spring of the timepiece mechanism by means of any suitable toothed gearing and possesses escaping force tending to rotate clockwise at all times, and alternately catches and releases the teeth of the gear-wheels 3 and 1 through the pins 7 and 8 and advances or rotates them intermittently by one tooth at a time. And whenv the gear-wheels 3 and at rotate, the slant side provided at the end of each tooth presses the pins 7 and 8 and imparts oscillation to the lever 6 and moves the balance or the pendulum as is usually the case with an ordinary timepiece mechanism. In

my invention, each of the teeth of the gearwheel 3 has its side facing the direction of rotation. that is, its right side, curved into an arc-shape to conform with the path of oscillation of the engaging pin with, and each of the teeth of the gear-wheel e has its right side curved likewise with relation to the engaging pin, differing only in the positions or directions of the curved sides, they being dianietrical, and this constitutes the main feature of my present invention. To describe this feature more fully:

In Fig. 3, each of the teeth 3, of the rear gear-wheel 3 corresponding to the left-hand pin 7 has its right side a-a arc-shaped, tending to increase in width toward the root or base, conforming with a circular are described with the axle 5 as center and with the length of the arm extending from the said axle to the outer periphery of the pin 7 as radius. And as shown in Fig. at, each of the teeth a of the front gear-wheel 4: corresponding to the right-hand pin 8 has its right side 5-?) arc-shaped, tending to decrease in width toward its root or base, conforming with a circular are described with the axle 5 as center and with the length of the arm extending from the said axle to the pin 8 as radius. Fig. 3 shows the manner in which one of the teeth 3, is received by the left-hand pin 7, and in this case the pin 7 will slide along the right side a-a of the tooth 8, as the lever 6 oscillates clockwise, but then the side ([/CL is so shaped as to conform with an are described with the axle 5 as center and the arm 5-7 as radius, so that the gear-wheel will. remain in rest in spite of the oscillation of the pin; and, at the moment when the pin finally gets out of engagement with the side (e-a the other pin 8 intervenes between the two teeth a, and 4%, thus releasing the gear-wheel for an instant and advancing or rotating it by one tooth through the action of the winding spring, and the upper side a-c of the tooth 3, presses the pin 7 and imparts rotation to the lever G. And as soon as the pin 7 has got out of engagement with the extremity of the upper side 0 of the tooth 3 owing ,to change in declination of the lever G, as

shown in Fig. 4t, the other pin 8 is received by the right side 7)Z) of the tooth 4 of the gear-wheel 1-, and since this side, too, is so shaped as to conform with an are described with the axle 5 as center and the arm 5-8 as radius, the gear-wheel a can remain in absolute rest in spite of any oscillation of the lever while the said side is in contact with the pin, and at the moment when the pin 8 has left the right side of the tooth 4t and shifted to the upper'slant side Z)-cl while the lever 6 is oscillating counter-clock wise, the gear-wheel is released and advanced or rotated, and then the left-hand pin 7 receives the succeeding tooth 3,, and so .011, thus making it possible to advance or rotate the gear-wheels periodically and intermittently without the slightest recoil during the rest.

In pin-anchor escapements known hitherto, a single escapement-wheel has been used and so constructed as to cause two anchorpins, front and rear, to act on the same, and so the front side of each tooth has generally been shaped rectilinearly according to the direction of the radius, with the consequence that the shape of the said side of the tooth cannot closely conform with the path of oscillation of a lever, and produces tendency to push the wheel more or less in an opposite direction in defiance to the action of the winding spring; in other words, the so-called recoil cannot be avoided with such forms of pin-anchor eseapements. And, if such recoil is produced at each movement of the escapement, it will not only consume the energy or force of the spring and impairs durability of running of the timepiece, but also will tend to make the timepiece incorrect in its function of indicating time by causing great difference in escaping actions according to the strength of the winding spring. On the contrary, in my invention two escapement-wheels are used instead of one to eliminate these defects, and the front side of each of the gear-wheels has been so shaped, as to conform with the path of oscillation of the engaging pin with, and so there is no possibility of producing any recoil during the period of rest, thus making it possible to run the same smoothly, keep time very correctly, and increase durability of the mechanism.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A pin anchor escapement for time pieces including escapement wheels provided with teeth,.a pallet mounted adjacent each of the wheels for periodically stopping and releasing the wheels, and arcuate edges on the teeth of the escapement wheels described from a point coincident with the axis of rotation of the pallet to prevent recoil of the escapement.

2. A pin anchor escapement for time pieces including escapement wheels provided with teeth, a pallet mounted adjacent each of the wheels for periodically stopping and releasing the wheels, and oppositely curved arcuate edges on the teeth of each of the escapement wheels described from a point coincident with the axis of rotation of the pallet to prevent recoil of the es- :a-pement.

3. A pin anchor escapement for time pieces including escapement wheels provided with teeth, a pallet mounted adjacent each of the wheels, arcuate edges on the teeth of one of the escapementwheels deaxis of rotation of the pallet and of a curva- 1,34s,79s. a

scribed from a point coincident with the "and means on the pallet for alternately enaxis of rotation of the pallet, arcuate edges gaging the teeth on each of the escapement on the teeth of the other of the wheels dewheels whereby to periodically stop and re- 10 scribed from a point coincident with the lease the Wheels Without recoil.

In testimony whereof I afiix my signature ture opposed to the curvature of the arcuate hereto.

edges of the teeth of the first named wheel, TOMOKIGHI TODA.

Images