US3665697A - Driving mechanism for electronically controlled timepiece - Google Patents

Driving mechanism for electronically controlled timepiece Download PDF

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Publication number
US3665697A
US3665697A US90573A US3665697DA US3665697A US 3665697 A US3665697 A US 3665697A US 90573 A US90573 A US 90573A US 3665697D A US3665697D A US 3665697DA US 3665697 A US3665697 A US 3665697A
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United States
Prior art keywords
tooth
pawl member
ratchet wheel
pawl
teeth
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Expired - Lifetime
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US90573A
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English (en)
Inventor
Peter Dome
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SOC SUISSE POUR L'INDUSTRIE HORLOGERE SA
SUISSE POUR L IND HORLOGERE SA
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SUISSE POUR L IND HORLOGERE SA
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    • G—PHYSICS
    • G04—HOROLOGY
    • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C13/00—Driving mechanisms for clocks by primary clocks
    • G04C13/08—Secondary clocks actuated intermittently
    • G04C13/10—Secondary clocks actuated intermittently by electromechanical step advancing mechanisms
    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B11/00—Click devices; Stop clicks; Clutches
    • G04B11/02—Devices allowing the motion of a rotatable part in only one direction
    • G04B11/04—Pawl constructions therefor, e.g. pawl secured to an oscillating member actuating a ratchet
    • G—PHYSICS
    • G04—HOROLOGY
    • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C5/00—Electric or magnetic means for converting oscillatory to rotary motion in time-pieces, i.e. electric or magnetic escapements

Definitions

  • FIG. 2 FREQUENCY PULSE OJCILLAIUE DIV/DEE SHAPEB
  • Such a system which positively locks the ratchet wheel at the end of each swing of the balance lever, is highly useful since it minimizes the possibility of an untimely advance of the wheel in response to external shocks. Nevertheless, during part of each swing the dogs of the lever are separated sufficiently from the ratchet teeth to enable at least a limited rotation of the wheel by impact or vibration from outside the system so that oscillation of the lever may be temporarily blocked by the resulting disalignment with consequent skipping of one or more stepping cycles.
  • the primary object of my present invention is to provide latch means in a clockwork of this general type for positively immobilizing the ratchet wheel during those phases of operation when its teeth are disengaged from the associated stepping mechanism.
  • a more specific object is to provide intermittently effective latch means for the purpose set forth whose tooth-engaging element is automatically withdrawable from the orbit of the ratchet teeth without the assistance of an additional source of energy-(other than the pulse generator driving the balance lever), such withdrawal being sufficiently rapid and sustained to minimize the time of contact between the latching element and the moving ratchet teeth and to reduce the wear upon these teeth inherent in such contact.
  • an elongate pawl member which is engageable with the pointed ratchet teeth at a location offset from the stepping mechanism and which has an end face positioned to contact the trailing flank of an aligned ratchet tooth, i.e., the rear flank of that tooth as viewed in the direction of rotation, this pawl member being swingable about a fulcrum lying on a line perpendicular to that rear flank when the pawl member is in a contact position in which its end face obliquely intersects the orbit of the teeth.
  • the mass of the pawl member and the biasing force acting thereon should be so related that, in response to an incremental rotary motion imparted to the ratchet wheel by the stepping mechanism, the pawl member is deflected to an extent and for a time sufficient to clear the tip of the oncoming tooth during the remainder of the stepping movement, i.e., while the latter tooth takes the place of its predecessor.
  • the line running through the fulcrum of the pawl member at right angles to the rear flank of the aligned tooth in the quiescent position of the system terminates substantially at the tip of that tooth, with the end face of the pawl member narrow enough so as not to intercept the tip of the next tooth upon its return swing.
  • the pawl member may be biased by a spring force, electromagnetically, or in any other suitable manner and may coact with a stop blocking its swing past the contact position under the urging of its biasing force.
  • this member may conveniently be an at least partly ferromagnetic bar in the field of an associated magnet.
  • a resilient biasing force may be inherent in the pawl member itself, as where the latter is designed as a reed clamped at an end remote from the ratchet wheel, or may be supplied by a separate loading spring.
  • FIG. 1 is a somewhat diagrammatic plan view of an electromechanical clockwork incorporating a driving mechanism according to my invention
  • FIG. 2 is a cross-sectional detail view taken on the line Il II of FIG. 1;
  • FIG. 3 is an explanatory diagram showing parts of the mechanism of FIG. 1 on a larger scale.
  • FIG. 4 is a diagrammatic view similar to FIG. 3, illustrating a modification.
  • FIG. 1 shows major parts of a clockwork of the type disclosed in my above-identified application, Ser. No. 838,422, now US. Pat. No. 3,604,201, including an oscillator OS working into a frequency divider D whose output is delivered to a pulse shaper ER generating a train of stepping pulses of properly calibrated frequency.
  • These stepping pulses appear on an output lead of unit ER integral with two parallel spiral springs 7 (only one shown) which bracket a balance lever l and tend to swing it counterclockwise, i.e., in a sense opposite that of arrow F, about the axis of a shaft 2 transversing the center of that lever.
  • lever I carry respective dogs 1a, lb with beveled edges facing in the same direction, these dogs being alternately swingable toward the axis of a ratchet wheel S which may be directly or otherwise positively connected with the seconds hand 21 of the timepiece controlled by the illustrated system.
  • the hour and minute hands 22, 23 are also driven from ratchet wheel S, in the conventional manner, by a gear train diagrammatically illustrated at 20. If the output frequency of stage ER is 1 Hz, wheel S should have 60 teeth so that hand 21 may perform one revolution per minute if its coupling with wheel S has a transmission ratio of 1:1.
  • An arm 9 rigid with lever 1 is swingable between two fixed stops l3 and 14, being urged against stop 14 by the coil springs 7.
  • the two springs are mutually insulated in a manner not further illustrated and are included in the energizing circuit of a coil 10 movably mounted between two permanent horseshoe magnets 11a, 11b so that its turns intersect the lines of force emanating from each of these magnets.
  • the inner end of the spring 7 visible in the drawing, aside from being anchored to the lever 1, is also mechanically and galvanically connected to a terminal of coil 10 whose other terminal is similarly secured to the companion spring, the clamped outer end of the latter spring being grounded or otherwise returned to the second output terminal of pulse generator ER.
  • ratchet wheel S The teeth of ratchet wheel S are pointed and have beveled rear flanks s (FIGS. 3 and 4) coacting with the complementarily beveled ends of dogs la, lb whereby each reciprocation of balance lever 1 steps the ratchet wheel S in a counterclockwise sense (arrow F,,) by one tooth division. After each advance by a full step upon a reciprocating swing of the lever, its dog lb positively engages in the gap between two adjoining teeth as illustrated in FIG. 1.
  • stage ER may include a differentiation circuit to generate paired pulses of opposite polarity, the second (e.g., negative) pulse of each pair initiating an early return swing of lever I to withdraw its dog In from the ratchet wheel S before the next tooth hits that dog so that the momentum imparted to the wheel is not wastefully dissipated.
  • the angle included by the coacting beveled faces of dog In and the engaged tooth with the radius of wheel .a' through the point of engagement advantageously is about 45 for optimum energy transfer, as likewise pointed out in the earlier application.
  • a latching device or detent Spaced from the aforedescribed stepping mechanism along the periphery of ratchet wheel S is a latching device or detent comprising a fiat bar 100 of magnetizable material which is pivoted on a fixed pin 101 and whose end'100A intermittently engages the teeth of wheel S, two of which have been designated d and d,.
  • the opposite end 1008 of bar 100 moves between two pole pieces 103, 103A lying on opposite sides of a permanent magnet 102 as best seen in FIG. 2.
  • a fixed support 105 for magnet 102 and its pole pieces 103, 103A carries an adjustable abutment 104 held in position thereon by a screw 106 and normally bearing upon a side face of bar 100, thereby limiting the counterclockwise swing of the bar about pin 101 in response to the magnetic biasing force.
  • the arrested position of the bar can be very precisely adjusted upon loosening of screw 106 and a displacement of abutment 104.
  • the magnetic force restores the bar to its operative position illustrated in FIG. 1; it is now aligned with tooth d,, the ratchet wheel S having come to rest in its new angular position.
  • FIG. 4 I have shown a modified detent with a pawl member in the form of a reed 108 clamped in a fixed support 109 which establishes a virtual fulcrum for the reed, this reed being swingable within a range xx and carrying at its free end a block 107 having a side facel07a and an end face 107b, the latter coacting with the rear flanks of the ratchet teeth aligned therewith essentially as heretofore described with reference to FIGS. 1-3.
  • r represent the radius of point P as measured from the fulcrum 0 of the pawl
  • k be a fractional coefficient, ranging between 0 and I, which may be referred to as the bounce factor and which is given by the ratio of the velocities of a given object (here the pawl after and before rebounding from a fixed obstacle (here the tooth d, considered stationary at the moment of impact), its magnitude depending upon the materials of the object and the obstacle, I
  • w be the angular velocity of pawl 100 after impact
  • A be the velocity ratio iri /m which in the present case is close to unity since 0 6
  • B 7 the angle between the same tangent and the radius r
  • t is the duration of the clockwise swing of pawl 100 (against the action of its magnetic biasing force) under the impact of tooth d, and if t is the time required for tooth d to move into the position of tooth d the first condition to be satisfied in order to prevent interference of pawl- 100 with the motion of wheel S is t zt which leads to the relationship I i z E 8 M mi;
  • Equation l the natural frequency of the weighted re
  • a driving mechanism for a timepiece comprising:
  • a unidirectionally rotatable ratchet wheel forming part of a gear train for driving the hands of said timepiece, said ratchet wheel being provided with pointed teeth forming sloping rear flanks as viewed in the direction of rotation thereof;
  • electromagnetically operable stepping means engageable with said teeth for periodically advancing said ratchet wheel by increments equal to one tooth division;
  • pawl member engageable with said teeth at a location offset from said stepping means, said pawl member having an end face positioned to contact the rear flank of an aligned tooth between advances of said ratchet wheel and being swingable about a fulcrum lying on a line perpendicular to said rear flank in a contact position in which said end face obliquely intersects the orbit of said teeth;
  • said pawl member consists at least partly of ferromagnetic material, said biasing means including a magnet tending to draw said pawl member against said stop means.
  • said pawl member comprises an elastic reed clamped at an end remote from said ratchet wheel and provided at its opposite end with an enlarged head forming said end and side faces.
  • said stepping means comprises a two-armed balance lever having a dog at each end alternately engageable with the teeth of said ratchet wheel.
  • said stepping means further comprises a spiral spring anchored to said lever and a mobile electromagnetic coil mechanically connected with said spiral spring.
  • said stepping means includes a source of periodic current pulses, said spiral spring being electrically conductive and being connected in series with said coil across said source.
  • a mechanism as defined in claim 7 45said rear flank includes an angle of substantially 45 with the radius of said ratchet wheel passing through the tip of the corresponding tooth, at least one of said dogs having a beveled face engageable with said rear flank for advancing said ratchet wheel.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electromechanical Clocks (AREA)
  • Transmission Devices (AREA)
US90573A 1969-11-20 1970-11-18 Driving mechanism for electronically controlled timepiece Expired - Lifetime US3665697A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1728169A CH604223B5 (is") 1969-11-20 1969-11-20

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US3665697A true US3665697A (en) 1972-05-30

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US90573A Expired - Lifetime US3665697A (en) 1969-11-20 1970-11-18 Driving mechanism for electronically controlled timepiece

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CH (2) CH604223B5 (is")
DE (1) DE2057715A1 (is")
FR (1) FR2077529B2 (is")

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3783600A (en) * 1971-07-29 1974-01-08 Junghans Gmbh Geb Electromechanic driving mechanism for the hands of a timepiece
US3807388A (en) * 1970-09-29 1974-04-30 T Orr Heartbeat rate monitors
US3810355A (en) * 1971-03-20 1974-05-14 Seiko Instr & Electronics Electronic circuit for quartz crystal watch
US4032827A (en) * 1976-03-15 1977-06-28 Timex Corporation Driver circuit arrangement for a stepping motor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH626495B (fr) * 1977-05-02 Universo Sa Dispositif moteur pour garde-temps a affichage analogique.

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1585079A (en) * 1925-09-02 1926-05-18 Butticaz Eugene Electrical clockwork
CH343912A (de) * 1958-03-28 1959-12-31 Durowe Ag Sekundenzeigerantrieb in elektrisch angetriebenen Uhren
GB897082A (en) * 1958-06-16 1962-05-23 Reinhold Obergfell Improvements in or relating to electronic motion control systems for chronometric apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1585079A (en) * 1925-09-02 1926-05-18 Butticaz Eugene Electrical clockwork
CH343912A (de) * 1958-03-28 1959-12-31 Durowe Ag Sekundenzeigerantrieb in elektrisch angetriebenen Uhren
GB897082A (en) * 1958-06-16 1962-05-23 Reinhold Obergfell Improvements in or relating to electronic motion control systems for chronometric apparatus

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3807388A (en) * 1970-09-29 1974-04-30 T Orr Heartbeat rate monitors
US3810355A (en) * 1971-03-20 1974-05-14 Seiko Instr & Electronics Electronic circuit for quartz crystal watch
US3783600A (en) * 1971-07-29 1974-01-08 Junghans Gmbh Geb Electromechanic driving mechanism for the hands of a timepiece
US4032827A (en) * 1976-03-15 1977-06-28 Timex Corporation Driver circuit arrangement for a stepping motor

Also Published As

Publication number Publication date
FR2077529A2 (is") 1971-10-29
FR2077529B2 (is") 1974-12-06
CH1728169A4 (is") 1977-08-15
CH604223B5 (is") 1978-08-31
DE2057715A1 (de) 1971-05-27

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