US2031705A - Timepiece and the like - Google Patents

Description

Feb. 25, 1936. R, Q GRASEBY 7 2,031,705

TIMEIPIECE AND THE LIKE Filed May 12, 1934 Patented Feb. 25, 1936 f UNITED STATES PATENT OFFICE TIMEPIECE AND THE LIKE Robert Constantine Graseby, New Malden, England Application May 12, 1934, Serial No. 725,378 In Great Britain August 3, 1933 3 Claims. (01. 58-26) The present invention concerns improvements In the construction to be described the correcin or relating to time-pieces and the like which tion lever and its cam arm are the only oscillatory are controlled by synchronization with a source parts. of alternating electric current that has its fre- One feature of the invention is a time-piece quency controlled so as to be constant as is the or the like of the kind specified in which the case with many electric supply systems at the correcting movement is in the nature of an inpresent day, and which is of the kind (hereinstantaneous stab and withdrawal such that there after referred to as the kind specified) in which is no liability for it to produce alock on the drive, the time mechanism is always horologically in which the winding arbor is connected to its driven but is electrically synchronized irrespecwinding motor through rotary in contradistinctive of Whether it is operating fast or slow, in tion to reciprocatory connections, and in which which the winding arbor of the time mechanism the correcting mechanism has set intervals of is continuously rotated by a synchronous motor, correction which are very long compared with the and in which the synchronizing correction is perlimit of accuracy to which the clock can be read mitted by a frictional connection in the drive. 50 t at it ne pe a y comparatively In this way the time mechanism is corrected at fr q y and consequently Wear on the mechaset intervals irrespective of the rating of the esnism is comparat y ght. capement. Such an instrument has the advan- T inv w become more fully ppa tage that if the electric supply fails, the instrufr m the f l wi p i n, n un ion ment continues to function by reason of its horowith the accompa y diagrammatic drawing, of

logical drive. one illustrative construction according to the in- A previously proposed clock of the kind speci- VehtiOnfled had its horological drive wound from the In the drawin same electric motor that efiected the synchroni- Th figure i n exploded i mm i p rzation. This clock, however, had a very short spective view of so much of the illustrative concorrecting interval, so short indeed that prac- 5151116111011 35 is necessary the understanding tlcally half its duration was approximately less f the i ve t n. than the limit of accuracy to which the clock A time-switch comprises usual mechanism y could be read, this giving normally an adjusting which a sprin iv n drum ll drives a time period of 10 seconds or less, It. is t b n t d indicator indicated generally at l2 equivalent to that in order to overcome the frictional connecclock hands under control of a usual escap tion the correcting movement should be in the The d H Contains a Winding ShaIt l5 nature of a, hammer b1ow, so that ith u h a to which is attached a main spring I! (in this frequent adjustment there was naturally concase a 60- u p W ch is not attached to siderable wear on the parts. This clock also had e u H but which drives it by fr c on many reciprocatory or oscillatory parts. contact with its interior in known manner as The main object of the present invention is to i di d a 9; thus v rwi f h p in provide correcting mechanism having set inter- IT does not damage the c a i m since the vals of correction which are very long compared Sp n n Slip On the interior of the drum II. with the limit of accuracy to which the clock The mechanism by which the drum II drives can be read so that it need operate only comparathe m indicator (Clock hands) Comprises a tively infrequently and consequently the wear on toothed ring 2| fixed to the drum H, and gear the mechanism is comparatively slight; indeed Wheels 22, 23, 23a, 24, 24a, 25 and Spindle 26; the wear on the correcting mechanism may be the escapement l3 controls this drive throug comparable with the wear on the time mechagearing indicated generally at 27 Which eshes nism. Such a correcting mechanism gives long with gear Wheel bllfe with reasonable accuracy, since with a rea- In order to provide for synchronous correcsonably adjusted clock the inaccuracy during an tion, the following mechanism is provided.

interval of one hour is so small as to be negligi- Instead of being fixed to the spindle 31 as is ble for practical purposes. gear wheel 23a the gear wheels 23 and 23b are A further object is to provide correcting mechdriven from the spindle 3! through a friction anism which shall have a minimum of reciproslip-device comprising a spring contained within catory or oscillatory parts in contradistinction a casing indicated at 230'; thus relative moveto rotary parts whereby wear is reduced owing ment is possible between the wheel 23b and its to the elimination of the necessity for reversing. spindle 3|. In this construction the spindle 3| is the minute spindle of the mechanism, which makes one revolution in one hour. If the device were intended to act as a clock instead of as a time-switch, a minute hand would bev fixed to the spindle 3|. Also fixed to this spindle 3| is a toothed correction disc 33 provided with V-shaped gaps as 35, 31, 39 between adjacent teeth. In this particular construction there are 24 teeth, so that the distance between two adjacent teeth should rotate past a given point in 2 /2 minutes. Adjacent to the correction disc 33 there is pivoted to the frame on a pivot-pin 4| a correction lever 42 having at one end a V- shaped nose 43 which is adapted to enter and locate in any one of the gaps as 35; the other end of the lever 42 is formed for safety reasons with a portion 44 pivoted on a pin 45 which is normally held in position by a strong spring 46. Upon the portion 44 is pivoted a roller 41. The correction lever 42 is rocked suddenly at predetermined intervals as will now be explained. Mounted on the winding shaft I5 is cam-disc 5| upon which is pivoted at 52 a double cam-arm 53, 54', which is normally held in radial position against a stop 55 on the cam-disc by a spring 56. The cam-disc 5| is by any convenient means rotated (once in 62 minutes) from a synchronous motor. Upon the frame there is mounted a stop 6| which is located in the path of movement of the cam-arm part 53.

As the cam-disc 5| continues to rotate counterclockwise after the part 53 has contacted with the stop 6|, the cam-arm will be rocked from its radial position to permit the p.art'53 to pass the stop 6|. When it passes the stop 6| the spring 56 will snap it back into radial position and in this movement the part 54 will strike the roller 47; the correction lever 42 will he suddenly rocked and its nose 43 will be suddenly forced into the adjacent V-shaped gap as 35 and then as suddenly released. If the gap 35 is exactly opposite the nose 43 when this occurs the correction disc 33 is not affected; if

however the time mechanism is running incorrectly, either fast or slow, the correction disc will be rotated slightly relatively to the escapement control wheel 23b and will rotate the spindle 3| correspondingly and will so rotate the time indicator into synchronism with the synchronous motor. It is to be noted that because the lever 42 is both suddenly struck and suddenly and immediately released by a single snap movement of the part 53, the nose 43 does not in any way tend to lock the correction disc 33. The disc 33 is struck, moved and released instantaneously.

In this particular construction not only the cam-disc 5| but also the winding shaft i5 is driven from a synchronous motor; in fact, both are driven from the same synchronous motor. To eifect this the winding shaft I5 is driven through gearing H from the shaft 13 of a synchronous motor, the arrangement being such that the main spring I1 is constantly overwound by a considerable amount, in this case in a ratio of 5 to 1; thus, if the motor stops for 5 hours and the main spring l1 unwinds for that time, then the motor on re-starting will in 1 hour have rewound the spring fully. Thus the timepiece is always spring (horologically) driven, but the winding shaft I5 is wound electrically. The cam-disc 5| in order that it shall be driven by the motor-shaft I3 is fixed to the winding shaft I5.

The operation is as followsz-Assume that the time mechanism is very badly adjusted and is going slow by half a minute every hour. The correction disc 33 will therefore be lagging. At the expiry of 62 minutes the synchronous motor will have rotated the cam-disc 5| one rotation. Consequently the cam-arm 54 will strike the roller 41 and rock the correction lever 42; the nose 43 will enter the adjacent V-shaped gap 35 which will not be exactly opposite the nose and will force the correction disc 33 forwardly and so through the gears 23a, 24, 24a, and 25 will move the spindle 26 into correct synchronous position; gears 23 and 231) are not moved as they are only friction tight on the spindle 3|, so there is no interference with the escapement. Thus the time mechanism is corrected every 62 minutes. It will be understood that if the clock is reasonably adjusted (for example, so that it goes fast or slow only by a minute or so a day) the amount of adjustment at each correction stroke is very small. Indeed if the synchronous motor stops for several hours it will in these circumstances be able to make a proper correction when it re-starts, seeing that even in that time the variation from true time will be less than 1% minutes, i. e. than half the width of the V-shape'd-gap' 35.

By rotating the correction disc 33 once in 60 minutes while the cam-disc 5| rotates once in 62% minutes, it is provided that normally the nose 43 enters, every time it operates, a gap next to the gap it last entered; thus the nose enters any individual gap only once in 24 rotations of the correction disc, that is, once in 24 hours; consequently, wear on' the teeth of the correction disc is small.

What I claim is:

1. Time-piece to be operated from a synchronous motor, comprising an indicating device, a driving spring, a driving connection therebetween including a slowly rotating element, a shaft to be driven by the synchronous motor, a tooth-gapped synchronizing member operatively connected with said element, a co-acting synchronizing toothed member, snap actuating means for periodically engaging said toothed memberin said gapped member with a sharp stabbing action, loading means acting. upon said toothed member for instantaneously retracting it from said gappedmember, and a driving connection between said shaft and actuating means whereby the latter is driven with a period differentiated from the time of rotation of said element by the quotient of that time divided by the number of tooth-gaps of the tooth-gapped member so that the toothed member engages succes-- sively in the said tooth-gaps. Y

2. Time-piece to be operated from a syn chronous motor, comprising an indicating device, a driving spring operatively connected with said device, a shaft to be driven by the s-ynchronous motor, a rotary tooth-gapped synchronizing member operatively connected with said device, a toothed co -acting synchronizing member, a lever carrying said member atan end, a support operatively connected with said shaft for rotation thereby, a hammer device pivoted on said support and rotatable'therewith, a loading spring acting between said support and hammer device, the other end of said lever extending into the path of said hammer device, and a stop located in the said path just in front of said lever-end, and adapted for arresting said hammer device until the continued rotation of said support permits said hammer device to slip past said stop under the influence of its loading spring and to strike said lever-end with a momentary hammer-blow producing a stab-like engagement of the toothed member in the tooth-gapped member.

3. Time-piece according to claim 2, wherein the lever consists of two parts one of which carries the toothed synchronizing member and the other terms the end struck by the hammer device, a pivotal connection between the two parts,

stop means preventing the said other lever-part from turning on the pivotal connection towards the hammer device, and a spring, stronger than the loading spring, arranged to act between the two parts in such a direction as to tend to turn the said other lever-part towards the hammer device.

ROBERT CONSTANTINE GRASEBY.

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