Unidirectional rotary drive coupling device for a watch movement

Claim 2

A unidirectional rotary drive coupling device for a watch movement, comprising: A first and a second toothed wheel rotatively mounted about a common axis and axially spaced apart from each other; an intermediate member positioned in the axial space between said teeth and being rigidly fastened to said first wheel, said intermediate member including a ratchet toothing; a pawl mechanism on said second wheel engageable with said ratchet toothing whereby said first and second wheels are unidirectionally rotatively interconnected through said ratchet toothing and said pawl mechanism, and including a central bore extending throughout the axial extent of said wheels and of said intermediate member; a hub member rigidly fastened to said second wheel and extending through said bore, said intermediate member and said hub member being fastened to said first and second wheels respectively, along mutually coextensive axially lengthwise portions thereof; and cooperating abutment means on said hub member and on said intermediate member restricting axial displacement of said first wheel in a direction away from said second wheel, said abutment means extending axially no further than the axially outermost radial surface of said first wheel, whereby the axial thickness of said device is no greater than the sum of the axial thicknesses of said first and second wheels and of the thickness of said pawl mechanism plus a reasonable clearance to permit movement of the respective parts relative to each other.

Claim 3

The device of claim 1, said intermediate member and said first wheel being secured to each other by means of radial crimp fit of said first wheel about one end of said intermediate member and said second wheel being likewise secured to said hub member.

Claim 4

A unidirectional rotary drive coupling device for a watch movement, comprising: A first and a second toothed wheel rotatively mounted about a common axis and axially spaced apart from each other; an intermediate member positioned in the axial space between said teeth and being rotatively rigid with said first Wheel, said intermediate member including a ratchet toothing; a pawl mechanism on said second wheel engageable with said ratchet toothing whereby said first and second wheels are unidirectionally rotatively interconnected through said ratchet toothing and said pawl mechanism, and including a central bore extending throughout the axial extent of said wheels and of said intermediate member, said pawl mechanism comprising a plurality of pivoted pawls arranged symmetrically circumferentially about said ratchet toothing, each pawl including a first and a second nose circumferentially spaced apart from each other relative to said ratchet toothing, said pawls being arranged whereby only one of said noses on each of said pawls may engage said toothing at any one time, said first nose on each pawl being a locking nose arranged to lockingly engage said ratchet toothing, and said second nose on each pawl being a change nose arranged to be pushed radially away from said ratchet toothing pursuant to rotation of the latter in either rotative sense; a hub member rigidly secured to one of said wheels and extending through said bore and cooperating abutment means on said hub member and on said intermediate member of the other one of said wheels, restricting axial displacement of said one wheel in a direction away from said other wheel.

Claim 5

A unidirectional rotary drive coupling device for a watch movement, comprising: A first and a second toothed wheel rotatively mounted about a common axis and axially spaced apart from each other; an intermediate member positioned in the axial space between said teeth and being rotatively rigid with said first Wheel, said intermediate member including a ratchet toothing; a pawl mechanism on said second wheel engageable with said ratchet toothing whereby said first and second wheels are unidirectionally rotatively interconnected through said ratchet toothing and said pawl mechanism, and including a central bore extending throughout the axial extent of said wheels and of said intermediate member, said pawl mechanism comprising a plurality of pivoted pawls arranged symmetrically circumferentially about said ratchet toothing, each pawl including a first and a second nose circumferentially spaced apart from each other relative to said ratchet toothing, said pawls being arranged whereby only one of said noses on each of said pawls may engage said toothing at any one time, said first nose on each pawl being a locking nose arranged to lockingly engage said ratchet toothing, and said second nose on each pawl being a change nose arranged to be pushed radially away from said ratchet toothing pursuant to rotation of the latter in either rotative sense; a hub member rigidly secured to one of said wheels and extending through said bore and cooperating abutment means on said hub member and on said intermediate member of the other one of said wheels, restricting axial displacement of said one wheel in a direction away from said other wheel.

Claim 6

The device of claim 3, said pawls each comprising a pair of arms extending in generally opposite direction from the pivot axis of the pawl, said noses being located on a respective different one of said arms.

Claim 7

The device of claim 3, said pawls each being pivoted about a fixed pivot axis relative to said second wheel.

Claim 8

The device of claim 3, said ratchet toothing comprising a plurality of ratchet teeth circumferentially spaced apart from each other to an extent so as to permit a degree of free rotation of said intermediate member relative to said pawl mechanism pursuant to the driving engagement of said first nose being transferred from one of said ratchet teeth to a next succeeding ratchet tooth.

Claim 9

The device of claim 3, wherein said pawls are arranged with each said first nose thereof in a different position of engagement with said ratchet toothing whereby only one of said first noses lockingly engages said toothing at any one time and whereby the lost motion in changing over such locking engagement from one to the other of said first noses is equal to a fraction of the circumferential pitch between the ratchet teeth.