Mechanism for driving a rotating jumping member in a timepiece |
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| 申请号 | US49842874 | 申请日 | 1974-08-19 | 公开(公告)号 | US3871171A | 公开(公告)日 | 1975-03-18 |
| 申请人 | EBAUCHES SA; | 发明人 | CHARBONNEY ADRIEN MAURICE; PERUCCHI NORBERT; BELOT MICHEL; GIGER URS; | ||||
| 摘要 | A mechanism for driving a rotating jumping member in a timepiece comprising a driving member rotating at a constant speed and coupled to the jumping member by a spring, a pallet pivoting about a fixed axis parallel to the common axis of the driving and jumping members, and a cam integral with the driving member and having a profile formed of lugs distributed at a uniform pitch about the aforesaid common axis, the jumping member having teeth which are successively blocked and then released by the pallet in the course of rotation of the jumping member. | ||||||
| 权利要求 | 1. A mechanism for driving a rotating jumping member in a timepiece, comprising a driving member rotating at a constant speed and coupled to said jumping member by a spring, a pallet pivoting about a fixed axis parallel to the common axis of said members, and a cam integral with said driving member and having a profile formed of lugs distributed at a uniform pitch about said common axis, said jumping member having teeth which are successively blocked and then released by said pallet in the course of the rotation of said jumping member, wherein said pallet comprises two beaks, each provided with a locking-plane and a tip, each locking-plane cooperating with said teeth and each tip cooperating with said profile, and wherein said locking planes are so oriented that the pressure of said teeth upon each of said planes subjects said pallet to a torque which causes it to pivot and to press against said profile. 2. A mechanism in accordance with claim 1, wherein the profiles of said locking-planes and those of said lugs are paired in such a way that the torques exerted by said pallet on said cam partially compensate the variations in resistance due to the tensing of said spring. 3. A mechanism in accordance with claim 1, wherein said two beaks comprise an entry-beak and an exit-beak, and wherein said locking-planes are so oriented that a line drawn perpendicular to the locking-plane of said entry-beak through the tip of said entry-beak passes to the outside of said fixed axis, and a line drawn perpendicular to the locking-plane of said exit-beak through the tip of said exit-beak passes to the inside of said fixed axis. 4. A mechanism in accordance with claim 1, wherein said jumping member is freely engaged on a cylindrical bearing surface integral with said cam and is held axially in place by said cam on one side and by a shoulder integral with said cam on the other side. 5. A mechanism in accordance with claim 4, wherein said spring is situated in a recess in said cam. 6. A mechanism in accordance with claim 4, further comprising a tubular hub onto which said cam is driven. 7. A mechanism in accordance with claim 6, wherein said shoulder is formed by a collar made in one piece with said tubular hub. 8. A mechanism in accordance with claim 6, wherein said shoulder is formed by a washer fixed to said hub by riveting from the outside or the inside. 9. A mechanism in accordance with claim 6, wherein said spring is situated in recess in said driving member. 10. A mechanism in accordance with claim 1, wherein the orientation of said locking-planes is such that said teeth cause said pallet to pivot in the direction of disengagement and press the one of said two beaks which is not then in contact with said jumping member against said profile. 11. A mechanism in accordance with claim 10, wherein the number of said lugs is equal to the number of said teeth, and the maximum angular clearance between said cam and said jumping member is equal to half the pitch of the toothing of said jumping member. 12. A mechanism in accordance with claim 11, wherein each said lug comprises a crest in the shape of an arc of a circle concentric with said cam, a rear flank intended to retain said tips of said two beaks, and a forward flank having contour similar to that of said rear flank. 13. A mechanism in accordance with claim 12, wherein said rear and forward flanks each comprise two end portions more steeply inclined than the intermediate portion joining them. |
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