US3408810A

US3408810A - Jump seconds hand

Info

Publication number: US3408810A
Application number: US580120A
Authority: US
Inventors: Meitinger Heinz
Original assignee: United States Time Corp
Current assignee: United States Time Corp
Priority date: 1965-09-29
Filing date: 1966-09-16
Publication date: 1968-11-05
Anticipated expiration: 1985-11-05
Also published as: DE1523854A1; GB1099897A; DE1523854B2; CH1232566A4; CH479107A

Description

Nov. 5, 1968 MEITINGER JUMP SECONDS HAND 4Sheets-Sheet 1 Filed Sept. 16, 1966 INVENTOR HEINZ MEITINGER ATTORNEYS Nov. 5, 1968 H. MElTlNGER JUMP SECONDS HAND 4 Sheets-Sheet 2 Filed Sept. 16, 1966 INVENTOR HEINZ MEITINGER ATTORNEYS Nov. 5 1968 H. MEITINGER JUMP SECONDS HAND 4 Sheets-Sheet 3 Filed Sept. 16, 1966 INVENTOR HEINZ MEITINGER ATTORNEYS H. MEITING ER Nov. 5, 1968 v JUMP SECONDS HAND 4 Sheets-Sheet 4.

Filed Sept. 16, 1966 INVENTOR HEINZ MEITINGER ATTORNEY United States Patent 13 Claims. (Cl. 58-125) The present invention relates to horology and more particularly to a mechanism to actuate the seconds hand of a watch so that it moves in rapid starts and stops, i.e., in a jump-like fashion.

There has been for many years a demand for watches whose seconds hands, instead of moving smoothly around the dial, is progressed in jumps. Such jumps are step-bystep motions for each time the seconds hand moves one second, i.e., six degrees on the dial.

The requirements on the mechanism is that it change the steady rotational movement of the index wheel, which is the wheel receiving the watchs driving power, and convert it into a jerky motion of a short uniform length.

As the jump motion is required sixty times a minute and the watch should run for years, it is essential that the mechanism be sturdy and not subject to rapid wear. If a mechanism is simple it is less likely to fail in service than one that is complex. So the jump seconds mechanism should be simple. Such simplicity provides savings in the cost of manufacture and in repair.

Various mechanisms have been proposed and utilized for this purpose, but some of them are relatively fragile or costly. They must be adjusted as they are directly dependent upon the frequency of the balance wheel. In addition, as these mechanisms drive the seconds wheel directly, the movement of the seconds wheel is affected by amplitude variations of the balance wheel.

It is the objective of the present invention to provide a jump seconds hand mechanism for a watch which is relatively sturdy, simple, inexpensive and long wearing; which operates with any balance wheel frequency, and which. is independent of variations in balance wheel amplitude.

In accordance with the present invention, a mechanism is provided which includes a balance wheel or other regulator, such as a vibratory member, which is driven by well-known methods, for exmaple, by an electrical battery or a mainspring. The balance wheel oscillates a forked lever having elongated driving pins. The pins act on the teeth of an index wheel (escape wheel) to rotate the wheel. The index wheel is fixed to a shaft which is movable axially and is rotatable. This shaft is depressed against a spring by a camming arm which acts against the spokes of the index wheel. An indexing gear having a camming surface (a slant plane), preferably in the form of an elongated worm gear, is mounted on the same shaft as the index wheel. The teeth of the worm gear is in mesh with the seconds wheel. At the end of its camming action, the index wheel is suddenly released and its shaft is pushed quickly upward by the spring. This motion causes the worm gear to quickly turn the seconds wheel, in a jerky fashion, the amount required for the seconds hand to move one second. The worm gear does not rotate the seconds wheel during its axial depression.

The motive power to shift the seconds wheel is not produced, as in all other known shifting arrangements, by a direct drive, but exclusively by the intermediate drive mechanism of the present invention. This has the advantage of providing a constant torque transmission from the balance wheel to the index wheel. The one-second step of the seconds wheel, when it is caused by the worm gear, does not reflect amplitude variations of the balance wheel.

"ice

Further objectives and characteristics of the present invention will be explained in the following description of a preferred embodiment of the invention with the help of the schematical drawing accompanying this application, which shows the form of construction of said preferred embodiment.

In the drawings:

FIG. 1 is a diagrammatic perspective view of the parts forming the indexing arrangement of a wrist watch movement according to the present invention;

FIG. 2 is a cross-section taken through the parts shown in FIG. 1, in which the indexing member, a worm gear, is in its initial setting;

FIG. 3 is a cross-sectional representation in the same manner as FIG. 2, in which the indexing member is in its indexing position; and

FIG. 4 is a partial top view of the arrangement according to FIGS. 1 to 3.

The drawings show a part of the gear train of a wrist watch movement. The movement parts are located between an upper frame plate 10 and a lower frame plate 12 on which the necessary bridges are arranged. The seconds wheel 14 (fourth wheel) is carried on a staff 20 on which the seconds hand is fixed. The axle 20 is pivotable and is carried by

bridges

16 and 18, see FIG. 1. This axle 20 carries the second hand 22, as it is shown by dash lines in FIG. 1. The seconds Wheel 14 is driven by the indexing arrangement, designated as a unit by 24. The drive to the seconds wheel 14 is in such a manner that the seconds hand 22 will be jerkly indexed every second for one indexing step. This type of movement is sometimes called a jump seconds movement.

The indexing arrangement includes an indexing member, preferably in the form of a Worm gear 26. .Worm gear 26 engages with its teeth 28 in the tooth spaces of the teeth 30 of the seconds wheel 14. The worm gear 26 is fixed on a carrying axle 32. Axle 32 is journ-alled with its

pivots

34 and 36 between the

bridges

38 and 40 of the upper and lower frame plate. The worm gear 26 is solidly fixed on its carrying axle 32. The carrying axle 32 is axially slidable in the bearings of the

bridge

38 and 40.

A spring blade 42 acts as a control device. The spring blade 42 is fixed on the lower frame plate 12 and tries, by pushing on the bearing pivot 36 of the carrying axle 32, to raise the worm gear 26 into its final indexing position, shown in FIG. 3.

In the present form of construction, the drive of the carrying axle 32 occurs directly by a lever driving arrangement 44. The indexing arrangement 44 includes a lever staff 46 which carries an oscillatory lever 48 having two arms 50 and 56-. The lever arm 50, having a fork portion at its end, cooperates with

banking pins

52 and 54 to restrict the amplitude of the lever. The other lever arm 56 carries the

index pins

62 and 64, which are elongated compared to normal index pins. The

pins

62 and 64 cooperate with the teeth 58 of the index wheel 60 (escape wheel). The drive of the two-armed lever 48 occurs by means of an indexing pin 68 fixed on a roller 66. The roller 66 is fixed, in a known manner, on a balance staff 70 which is oscillated by the balance wheel (not shown). The drive of the index wheel can also occur in another .manner, e.g., by a supplementary wheel. A resonator (vibrator) may be used to drive the roller 66 or to drive a wheel meshing with a wheel on the staff 70. The balance wheel is oscillated by an electrical or mechanical drive system (not shown).

The jumping of the seconds wheel 14 (and of the hand 22) occurs because the worm gear 26 is jerkily converted from its lower initial setting shown in FIG. 2 into its indexing position shown in FIG. 3. This indexing motion is due to the release of the spring blade 42, which acts on the carrying axle 32. The upward motion of axle 32 causes the worm gear 26, having the flanks of its teeth engaged with 'te'eth'of the seconds wheel 14,"to"hit on the wear control arrangement 72 which times the release of spring 42. The index wheel 60 is provided with a hub 74 fixed on the carrying axle 32. This hub 72 is connected with the wheel rim 76 by spokes 78. i

A curved part 80 causes the axial shifting of the carrying axle 32. This curved part 80 is a lancing from the section 82 of the upper frame plate 10. The lower surface of the curved part 80 forms an end curved face 83 (see FIGS. 2 and 3). This curved face 86 penetrates the arched slots 84 located between the spokes 78, when the index wheel is in its indexing (jump) position. The spokes 78 are held and cammed against face 86 by the action of the spring blade 82 during the time the index wheel is being rotated step by step by the lever 48. The spokes 78 have their edges located in the sense of rotation and they act as a trip edge 87, together with the curved face 86 of the curved part 80.

The mode of operation of the control arrangement 72 is as follows: In order to obtain the one-second steps of the seconds wheel 14, the worm gear 26 must perform one indexing step every second from its initial setting to its indexing position. This requirement provides the dimensions of the spokes 78. The index Wheel must make one revolution in an integer number of seconds, for example, 1, 2, 3 or 4. The length of the slots 84 formed by the spokes 78 has to correspond with this integer number of seconds. In the illustrated form of construction, the driving arrangement is laid out in such a manner that the index wheel 60 performs a complete revolution in four seconds. Therefore the spokes 78 have an angular distance from each other so that, during the four seconds needed for a complete revolution of the index wheel, the Worm gear shifts four times. Therefore, the spokes 78 are ar ranged into two pairs, each spoke being displaced 90 relative to each other.

In FIGS. 1 and 2 the worm gear 26 is located in its highest position, in its initial setting with the spring 42 under tension. The worm gear 26 is forced downward into this position by the action of the curved part 80 on the spokes 78. The part 80 penetrates through the arched slots 84 and, with its curved face 86, cooperates with one of the spokes 78. The axial sliding of the carrying axle 82 and its worm gear 26 occurs automatically downwards to the position shown in FIGS. 1 and 2 as the index wheel is rotated. The shifting axial path is preferably from one to one-and -a-half times as long as the sixtieth part of the circumference of the seconds wheel. The length of axial motion is determined by the curvature of the surface 86 of the curved part 80.

'As soon as the end piece of the curved part 80 is released by one of the spokes 78 held against this curved part by the spring blade 42, the carrying axle and its worm gear moves within a fraction of a second upwards into the indexing position, ending in the position shown in FIG. 3. The curved part 80 will penetrate in the next arched slot 84 of the index wheel and the following spoke 78 will ride the curved face 86 of the curved part. The worm gear will be rotated during the 90 rotation of the index wheel into its depressed setting so that the same movement can be repeated.

The sloping face of the indexing member (worm gear) cooperates with the wheel carrying a hand. In the present case, the slope of the teeth of the worm gear must have such a dimension so that at the setback of the worm gear into its initial setting (during which it rotates and its teeth are engaged with the seconds wheel) the worm gear does not move the teeth of the index wheel beyond the regular backlash.

Modifications may be made in the present invention "ineafis'to move the staff carrying the worm gear may be on the worm gear in the form of raised portions, instead of on the index wheel. The raised portions would cam against a fixed arm.

I claim: 1. In a horological instrument having a seconds hand, a motive means, and a frame plate, a drive train to said seconds hand including an index wheel driven by said motive-means; an elongated gear connected to said index wheel and fixedly mounted on a .staff, said gear having teeth which slant relative to its axis and having axial positions of an initial setting and an indexing motion, means to journal said staff on the plate so that it is rotatable and movable axially, a seconds wheel adapted to be driven by said elongated gear and connected to said seconds hand, means to journal said seconds wheel on said frame plate, means to move said elongated gear staff axially from an initial setting into rapid indexing motion of said elongated gear, and means to control said axial motion so that it is operative once every second. 2. A horological instrument in accordance with claim 1, in which the elongated gear is formed as a worm gear.

3. A horological instrument in accordance with claim 2, in which the worm gear and the index wheel are arranged on a common carrying staff.

4. A horological instrument in accordance with claim 1, in which said control means is on the gear carryin staff.

5. A horological instrument in accordance with claim 1, in which the control means includes a fixed camming arm attached to the frame plate.

6. A horological instrument in accordance with claim 5, in which the index wheel has camming members which act against said fixed arm.

7. A horological instrument in accordance with claim 1, in which said control means is on the index wheel.

8. A horological instrument in accordance with claim 1, in which a stationary curved part fixed to the frame cooperates for the axial shifting of the carrying staff with camming members provided on the index wheel.

9. A horological instrument in accordance with claim 8, in which the camming members are arranged in pairs on a circular path on the index wheel.

10. A horological instrument in accordance with claim 9, in which the camming members are formed by spokes which connect the hub and the rim of the index wheel with each other.

11. A horological instrument in accordance with claim 10, in which, as seen in the sense of the rotation of the index wheel, the front edge of the spokes serve as a trip edge of the curved part.

12. A horological instrument in accordance with claim 1, in which the means to move the staff axially is a spring.

13. A horological instrument in accordance with claim 12, in which the spring is a spring blade which contacts a bearing pivot of the carrying staff.

References Cited ROBERT S. WARD, JR., Primary Examiner.

S. A. WAL, Assistant Examiner.

Claims

1. IN A HOROLOGICAL INSTRUMENT HAVING A SECONDS HAND, A MOTIVE MEANS, AND A FRAME PLATE, A DRIVE TRAIN TO SAID SECONDS HAND INCLUDING AN INDEX WHEEL DRIVEN BY SAID MOTIVE MEANS, AN ELONGATED GEAR CONNECTED TO SAID INDEX WHEEL AND FIXEDLY MOUNTED ON A STAFF, SAID GEAR HAVING TEETH WHICH SLANT RELATIVE TO ITS AXIS AND HAVING AXIAL POSITIONS OF AN INITIAL SETTING AND AN INDEXING MOTION, MEANS TO JOURNAL SAID STAFF ON THE PLATE SO THAT IT IS ROTATABLE AND MOVABLE AXIALLY, A SECONDS WHEEL ADAPTED TO BE DRIVEN BY SAID ELONGATED GEAR AND CONNECTED TO SAID SECOND HAND, MEANS TO JOURNAL SAID SECONDS WHEEL ON SAID FRAME PLATE, MEANS TO MOVE SAID ELONGATED GEAR STAFF AXIALLY FROM AN INITIAL SETTING INTO RAPID INDEXING MOTION OF SAID ELONGATED GEAR, AND MEANS TO CONTROL SAID AXIAL MOTION SO THAT IT IS OPERATIVE ONCE EACH SECONE.