US3537254A

US3537254A - Lever type mainspring winding device for clock

Info

Publication number: US3537254A
Application number: US809483A
Authority: US
Inventors: Masanori Kobayashi
Original assignee: Hattori Tokeiten KK
Current assignee: Hattori Tokeiten KK
Priority date: 1968-03-21
Filing date: 1969-03-19
Publication date: 1970-11-03
Anticipated expiration: 1987-11-03
Also published as: GB1214601A; DE1913458A1; DE1913458C3; DE1913458B2

Description

Nov. 3, 1970 MASANORI KOBAYASHI 1 3,537,254

LEVER TYPE MAINSPRING WINDING DEVICE FOR CLOCK I Filed Match 19, 1969 7 2 sheets-sheet 1 Nov. 3, 1970 Q MASANIORIZ KbYASl-li 7, I

LEVER T YPE MAINSPRING WINDING DEVICE FORCLOCK Filed March 19; 1969 2 Sheets-$heet z a FIG. 3

FIG.4

United States Patent Japan Filed Mar. 19, 1969, Ser. No. 809,483 Claims priority, appltiea/ltziim Japan, Mar. 21, 1968,

Int. Cl. G64b 3/00 US. Cl. 58-46 12 Claims ABSTRACT OF THE DISCLOSURE A lever-type mainspring winding device comprising a ratchet wheel rotated by a feed pawl, a detent mounted to a winding lever and having the central angle formed by both meshing positions of said feed pawl and said detent with said ratchet wheel corresponding to the value obtained by subtracting a smaller angle than the central angle subtended by one tooth of said ratchet wheel from an angle an integral number of times as large as the central angle subtended by one tooth of said ratchet wheel, thereby providing the winding lever with a free play angle through which it can move unaffected by the unwinding force of the mainspring.

BACKGROUND OF THE INVENTION 1.Field of the invention This invention relates to a device for winding a mainspring by means of a lever in a spring-operated clock.

2.Description of the prior art In a spring-operated clock in which a lever-type mainspring winding device is incorporated, it is preferred, for the sake of appearance, that the finger engaging part of the lever not be allowed to project outwardly from the cover of the clock too far, while on the other hand, in order to facilitate the winding operation of the stem, the knob of the stem must protrude far enough from the cover of the clock to be easily engaged by the users finger. The prior art lever-type mainspring winding devices are provided with a foldable or nestable lever and have the disadvantage that the lever tends to cause back-lash and to be damaged. Moreover, folding or contraction and extension of the lever is troublesome. This makes the winding operation of the mainspring of a clock encased in a tachograph more troublesome.

SUMMARY OF INVENTION This invention makes it possible to obviate the abovedescribed disadvantages inherent in the conventional devices and provides a novel and improved lever-operated mainspring winding device.

This invention makes it possible to provide a levertype mainspring winding device in a clock of the type wherein a mainspring is fixed at one end to a barrel and at the other end to a first wheel arbor. The device comprises a ratchet wheel fixed to a first wheel arbor, a stem pivotally mounted concentrically with said first wheel arbor, a feed pawl engageable with said ratchet wheel for rotating the ratchet wheel in response to the pivoting of said winding lever, a detent in engagement with said ratchet wheel for the prevention of reverse rotation of the ratchet wheel, and a central angle formed by both meshing positions of said feed pawl and said detent with said ratchet wheel corresponding to the value obtained by subtracting an angle smaller than the central angle subtended by one tooth from an angle an integral number of times larger than the central angle subtended by one ice tooth of said ratchet wheel. Thus, while the detent is preventing the ratchet wheel from being reversely rotated by the unwinding force of the mainspring, the feed pawl is freely swung within the range of a free play angle, which is an angle smaller than the central angle subtended by one tooth of said ratchet wheel, whereby the winding lever is initially allowed to pivot a predetermined distance without being placed under the action of the mainspring. Accordingly, in the initial stage of the mainspring winding operation, the winding lever can be readily moved to a position in which it is easy to catch by the users fingers within the range of said free play angle, thus making it possible to firmly catch the lever prior to the actual winding of the mainspring. Winding of the mainspring is effected by the lever being pivoted within the range of the angle left by subtracting said free play angle from the total pivotal angle of the lever. After the mainspring has been wound, the winding lever may be left in any position within the range of the free play angle of the lever.

An object of the invention is to provide a lever-type mainspring winding device for a clock which is both easy to operate and durable in structure.

Another object of the invention is to provide a levertype mainspring winding device which does not mar the appearance of a clock.

These and other features, advantages and objects of the present invention will become more apparent from the following description with reference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWING FIG. 1 is a side view, broken in part, of a tachograph incorporating a clock therewith;

FIG. 2 is a rear view of the clock portion;

FIG. 3 is an enlarged rear view of the clock portion, revealed by removal of a part of the back covering;

FIG. 4 is an enlarged section taken along line IVIV of FIG. 3; and

FIG. 5 is a section taken along line V-V of FIG. 4.

DETAILED EXPLANATION OF PREFERRED EMBODIMENT Referring now to the drawings and in particular to FIG. 1, a front lid 2 is pivotally connected by a hinge 3 to a casing 1 of a cylindrical tachograph, and a watch mechanism 4 covered with a cylindrical back cover 5 is provided on the backside of said front lid 2.

A first wheel arbor 6 is supported for rotation on a base plate 7 inside said cover and on a supporting plate 8 which is fixed to free columns 9 in an eccentric position of said cover 5as shown in FIGS. 2, 3 and 4. One end of said arbor 6 protrudes from the backside of said cover 5. A cylindrical barrel 10 is rotatable and concentrically fitted over said first wheel arbor 6. A mainspring 11 encased in the barrel 10 is mounted at one end to the barrel 10 and at the other end to the first wheel arbor 6, respectively.

A winding ratchet wheel 12 is fixed to a square shaft portion of the first wheel arbor rearwardly of said supporting plate 8. Rearwardly of said ratchet wheel 12 a hub 13 is rotatably fitted over the first wheel arbor 6, a segment or oscillation plate 14 is fixed to the front portion of the hub 13, and a manually operable winding lever 15 is fixed to the rear portion of the hub 13 protruding outwardly of the cover 5. A nut 16 is screwed into the rear end of said wheel arbor 6.

A feed pawl of winding click 17 for rotating the ratchet wheel 12 is rotatably supported by a pin 18 protruding from the front of the segment 14 and is normally pressed, by a hair spring 19, mounted on segment 14, into engagement with ratchet wheel 12, while a detent 20 is rotatably supported by a pin 21 which protrudes from the back of supporting plate 8 and is normally pressed into engagement with ratchet wheel 12 by a hair spring 22 mounted to the supporting plate. The pin 18 extends downwardly so as to come into contact with the edge of the supporting plate 8, while the other pin 21 extends upwardly so as to come into contact with the edge of the segment 14. These

pins

18 and 21 determine the angle of oscillation of said segment 14 and consequently the range of movement of winding lever 15 and depending upon their particular placement, the range of movement of winding lever 15 be regulated. The segment 14 is normally biased in a counterclockwise direction as seen in FIG. 3, by a weak return spring 23 fixed at one end to the base plate 7.

The central angle of one ratchet tooth is the angle which that tooth subtends as shown in FIG. 5, and for the ratchet wheel 12 shown, which has 18 teeth, the central angle 5 would 'be 20. The central angle between the two meshing positions of feed pawl 17 and detent 20 with the ratchet wheel 12 is set at an angle corresponding to the value obtained by subtracting an angle smaller than the central angle subtended by one ratchet tooth from an angle an integral number of times larger than said central angle. As shown, the central angle is 167 and is found by subtracting an angle of 13", which is the free play angle and smaller than the central angle of 20, from the central angle of 180, which is nine times 20 since the two meshing positions are set 9 teeth apart. Because of this, when the detent 20 is in mesh with the ratchet Wheel 12 thereby preventing the ratchet wheel from being reversely rotated the feed pawl 17 slides on the tooth surface of the ratchet wheel 12 without being subjected to the unwinding force of the mainspring within the range of the angle of 13 and is therefore freely swingable. Thus, the winding lever 15 is allowed to freely swing in the angular range from the position in which the pin 18 is in contact with the supporting plate 8, namely from an original position 0, as shown in FIG. 2, to the position away by said free play angle (13) from the original position, namely to a starting position S, and winding of the mainspring 11 is effected by pivoting the winding lever 15 from said starting position S to the position in which said pin 21 is in contact with the segment 14, namely to a terminal position T.

As shown in FIGS. 1 and 2, said winding lever 15 is placed in a recess 24 formed on the back of cover and the position of the unwinding lever with respect to the cover 5 is such that, when the winding lever is pivoted to the terminal position T, the longitudinal direction of the lever is in alignment with the radial direction of the cover, and when the winding lever is pivoted back to its original position, the foremost end of the lever is in approximate alignment with the periphery of the cover. Accordingly, during movement of the winding lever to effect winding of the mainspring, the foremost end of the stem gradually protrudes outwardly of the periphery of the cover 5 until it protrudes at the starting position S sufficiently to be caught by the users fingers and protrudes most in the terminal position T.

Winding of the mainspring is operated in the following manner. The lid 2 of a tachograph is opened to expose the backside of the clock 4. The distal end of winding lever 15, which is now in its original position 0, is pressed outwardly by the users finger to be placed in the starting position S. In this position, the winding lever is again fingered at its distal end and pivoted or swung reciprocatingly between the starting position S and the terminal position T.-It should be noted that in the terminal position T, winding lever coincides with the radial direction of back side cover 5. During the forward motion of said reciprocating swing, a segment 14 is rotated in a clockwise direction in FIG. 3 and rotates a ratchet wheel 12 clockwise thereby winding a mainspring 11. During the reverse 'motion of said reciprocating swing, a detent keeps the ratchet wheel 12 againstmovement in a counter clockwise direction and the feed pawl 17 returns to its original positionfAft'er winding ofthe'mainsprin'g has been completed, release of the fingers from the winding lever allows the return spring 23 to draw said lever 15 to its original position. As the spring 23 is weak, it sometimes happens that the winding lever does not return to its original position and in such a case, the lever may be returned to its original position by the users finger.

The restoration of the wound-up mainspring 11 is transmitted to other ordinary mechanisms (not shown) through a first wheel 25 provided on the periphery of the barrel 10.

What is claimed is:

1. A device for winding a spring comprising; ratchet means mounted for rotation, drive means releasably engaging said ratchet means for rotating said ratchet means, hold means releasably engaging said ratchet means for preventing rotation of said ratchet means, said drive means and said hold means being positioned with respect to each other in their rest position such that the central angle formed by both engaging positions corresponds to the value obtained by subtracting an angle smaller than a central angle subtended by one ratchet tooth from an angle an integral number of times larger than said ratchet tooth central angle.

2. A device as defined in claim 1, wherein said drive means comprises a feed pawl pivotally mounted on a first pin, lever means pivotally connected to said first pin for actuating said feed pawl, and said hold means comprises a detent pivotally mounted on a second pin.

3. A device as defined in claim 2, including a mounting plate, means mounting said lever means for relative movement with respect to said mounting plate.

4. A device as defined in claim 3, wherein said mounting plate is cylindrically shaped.

5. A device as defined in claim 3, wherein said lever mounting means is eccentrically positioned with respect to the geometrical center of said mounting plate.

6. A device as defined in claim 4, wherein said lever means is positioned relative to said mounting plate such that when the lever means is in its terminal position, it coincides with the radial direction of said mounting plate.

7. A device as defined in claim 4, wherein said lever means is positioned relative to said mounting plate such that when lever means is in its original position, its distal end is in alignment with the periphery of said mounting plate.

8. A device as defined in claim 2, including means for variably setting the range of movement of said lever means.

9. A device as defined in claim 3, wherein said mounting plate comprises a cover housing.

10. A lever-type mainspring winding device comprising a wheel arbor mounted for rotation, a ratchet wheel fixed to said wheel arbor, a hub rotatably supported on said wheel arbor, a winding lever connected to said hub, feed pawl means positioned to releasably mesh with said ratchet wheel, means connecting said feed pawl means to said hub whereby movement of said winding lever imparts rotation to said ratchet wheel through said feed" pawl means, a detent positioned to releasably mesh with said ratchet wheel, said feed pawl means and said detent being positioned with respect to each other in their rest position such that the central angle formed by both meshing positions corresponds to the value obtained by subtracting an angle smaller than the central angle subtended by one ratchet tooth from an angle an integral number of times larger than said ratchet tooth central angle.

11. A device as defined in claim 10, including spring means for nonnally biasing said winding lever to its original position.

12. A lever-type mainspring winding device for use in a timepiece comprisingra wheel arbor mounted for rotation, a ratchet wheel fixed to said wheel arbor, a hub rotatably supported on said wheel arbor, a winding lever connected to said hub, feed pawl means positioned to releasably mesh with said ratchet wheel, means connecting said feed pawl means to said hub whereby movement of said winding lever imparts rotation to said ratchet wheel through said feed pawl means, a detent positioned to releasably mesh with said ratchet wheel, said feed pawl means and said detent being positioned with respect to each other in their rest position such that the central angle formed by both meshing positions corresponds to the value obtained by subtracting an angle smaller than the central angle subtended by one ratchet tooth from an angle an integral number of times larger than said ratchet tooth central angle, whereby said winding lever is pro- 15 185-39; ss s1 vided with a free play angle through which it can move unaffected by the unwinding force of the mainspring.

References Cited UNITED STATES PATENTS RICHARD B. WILKINSON, Primary Examiner L. R. FRANKLIN, Assistant Examiner U.S. Cl X.R.