Crown/pusher for timepieces

This application claims priority to European Patent Application No. 19212451.9 filed on Nov. 29, 2019, the entire disclosure of which is hereby incorporated herein by reference.

The present invention relates to the field of horology and more specifically to an arrangement of a spring inside a crown/pusher.

Crown/pushers fitted to timepieces are provided with a return spring which is positioned around the stem of the crown. The spring generally rests at one end under the crown head and at the other end on a shoulder of the crown tube or on a washer arranged on this same shoulder. In use, the relative movement between the spring and the rotating components of the crown/pusher causes a phenomenon of scraping and thereby premature wear of the spring.

To overcome this drawback, U.S. Pat. No. 8,371,745 proposes inserting a washer to facilitate sliding at each end of the spring. Although sliding is facilitated, the relative movement between the washer integral with the crown head and the spring still generates friction which does not allow a continuous drive of the crown.

It is an object of the present invention to overcome the aforecited drawbacks by proposing a timepiece comprising a spring arranged inside the crown/pusher so as to eliminate friction between the spring and the rotating components.

To this end, the present invention proposes a crown/pusher provided with a spring placed inside a cage integral in rotation with the movement of the head, said spring being arranged inside the cage so as to be driven in rotation with the cage.

This arrangement of the spring inside a cage makes it possible to avoid any scraping between the spring and the recessed bottom of the crown and thereby increases the life of the spring. As the cage rotates with the spring, when an action is performed on the crown/pusher, the spring is not subjected to a relative movement with respect to a component. Further, as the cage has faces of similar shape to those of the faces on which it bears, normal friction is present in the bearing area, which ensures continuous driving of the crown.

The features and advantages of the present invention will appear upon reading the following detailed description, with reference to the following Figures.

FIG. 1 represents a plan view of a timepiece provided with a crown/pusher according to the invention.

FIG. 2 represents a longitudinal sectional view of the crown/pusher according to the invention.

FIG. 3 represents a three-dimensional view of the spring cage according to the invention.

FIG. 4 a represents a plan view of the spring cage according to the invention. FIGS. 4 b and 4 c are respectively sectional views along axes A-A and B-B of FIG. 4 a.

FIG. 5 a is a longitudinal half-section of the crown/pusher according to the invention in the final position mounted in the timepiece. FIG. 5 b represents the same view of the crown/pusher in the pressed-in position.

The present invention relates to a timepiece of the wristwatch type. It may be an electronic watch or a mechanical watch.

Referring to FIGS. 1 and 2 , the timepiece comprises, in a conventional manner, a case 1 provided with a middle part 2 and a crown/pusher 3 comprising a recessed/hollowed head 4 integral with a stem 7 moving inside a tube 6 attached to the case middle. Tube 6 is traversed by stem 7 connected to recessed head 4 . Recessed head 4 is mounted to move in translation and in rotation respectively along and around axis 7 a of stem 7 . According to the variant represented in FIG. 2 for an electronic watch, stem 7 is integral at its base with a retaining element 8 . A magnet 9 , for example a multipolar magnet, is attached to the distal end of stem 7 in order to cooperate with one or more sensors (not represented). For a mechanical watch, the stem can activate a function such as a chronograph function.

Crown/pusher 3 also includes a spring 10 arranged around stem 7 . According to the invention, return spring 10 is compressed inside a cage 11 shown in more detail in FIG. 3 . Cage 11 is disposed between tube 6 and stem 7 . It bears at one axial end on an inner face of recessed head 4 and at its other axial end on a base 6 a of tube 6 or, preferably, on a washer 14 which facilitates sliding, washer 14 being disposed on this same base 6 a . Cage 11 is made in two distinct parts: upper part 12 and lower part 13 , with upper part 12 integral with recessed head 4 . To this end, upper part 12 is attached to a core 5 extending partially around stem 7 from the inner face of recessed head 4 . The two upper and lower parts 12 and 13 cooperate, or in other words, interlock with each other. Upper part 12 of the cage rotates integrally with recessed head 4 , while lower part 13 of the cage is axially free with respect to the recessed head but driven in rotation by the upper part of the cage during the rotation of the recessed head. Further, upper part 12 is mounted on lower part 13 in order to move in translation along axis 7 a of stem 7 when the crown/pusher is pushed in. Different configurations can be envisaged to ensure the cooperation in rotation of the two parts and the movement in translation of the upper part with respect to the lower part. According to the variant of FIGS. 3 and 4 a - 4 c described in more detail below, upper part 12 has at least one portion 12 f interlocked in an opening 13 b of lower part 13 . By way of example, according to another variant that is not represented, the upper part can have at least one portion sliding inside a slide way arranged on an inner wall of the lower part.

Referring to the variant of FIGS. 3 and 4 a - 4 c, each part 12 , 13 has a cylindrical shape with a side wall 12 a , 13 a provided with at least one opening 12 b , 13 b and preferably two openings, or even three, four, etc. openings. Side wall 12 a , 13 a is delimited at one end by a base 12 c , 13 c pierced with a central hole and at the other end by a completely open base 12 d , 13 d . Openings 12 b , 13 b cut into side wall 12 a , 13 a define the contours of a ‘U’. In the illustrated example, the openings, which are two in number, are diametrically opposite. Openings 12 b , 13 b are delimited by portions 12 f , 13 f of side wall 12 a , 13 a . Side wall 12 a , 13 a is thus formed of portions 12 f , 13 f flanked by openings 12 b , 13 b . According to the invention, the two parts 12 , 13 are mounted in opposite directions with respect to each other, coaxially along stem 7 and with an angular shift of 90° with respect to one another. Thus, the open bases 12 d , 13 d face each other and portions 12 f of side wall 12 a of upper part 12 are interlocked in openings 13 b of side wall 13 a of lower part 13 in order, on the one hand, to allow the movement in translation of the upper part with respect to the lower part and, on the other hand, to allow the rotating upper part to drive the lower part in its movement. In the extended position of crown/pusher 3 , as represented in FIGS. 2, 3 and 5 a , portions 12 f of side wall 12 a of upper part 12 are slightly engaged in the respective openings 13 b of lower part 13 . In the pushed-in position of crown/pusher 3 as represented in FIG. 5 b , portions 12 f of side wall 12 a are engaged more deeply in openings 13 b . The maximum travel d represented in FIG. 5 a is limited by the lower face of recessed head 4 abutting against edges 6 b of tube 6 .

Spring 10 is housed in cage 11 between the two bases pierced with central hole 12 c , 13 c in the space delimited by side walls 12 a , 13 a and the rim 12 e, 13 e of the central holes. During use, this arrangement allows the spring to be rotated with the case, which prevents premature wear caused by a relative movement between the spring and a rotating component.

( 1 ) Case

( 2 ) Case middle

( 3 ) Crown/pusher

( 4 ) Recessed head

( 5 ) Core

( 6 ) Tube

a. Base b. Edge

( 7 ) Stem

a. Axis

( 8 ) Retaining element

( 9 ) Multipolar magnet

( 10 ) Return spring

( 11 ) Cage

( 12 ) Upper part of the cage

a. Side wall b. Opening c. Base with a central hole d. Open base e. Rim of the central hole f. Portion of the side wall

( 13 ) Lower part of the cage

a. Side wall b. Opening c. Base with a central hole d. Open base e. Rim of the central hole f. Portion of the side wall

( 14 ) Washer

( 15 ) Gasket

( 16 ) Cap