Step-by-step device for a ratchet-wheel

Claim 2

A step-by-step drive device for a ratchet-wheel acting through a pawl, said drive device comprising a movable cylindrical cup-shaped member having a closed end mechanically connected to the pawl, a coil connected to a source of electric pulses wound on said movable cup-shaped member, a cylindrical armature of a fixed ferrite core received in said cup-shaped member, said ferrite core forming an annular magnetic field surrounding said coil, a combined guide member and sealing ring for the cup-shaped member formed as a ring of low-friction lowdensity material fixed to the cup-shaped member and defining a clearance of several microns between the cylindrical armature and the combined guide member and sealing ring, said combined guide member and sealing ring together with said cup-shaped member and said ferrite core defining a pneumatic dampening means for said cup-shaped member, a damping member interposed between the closed end of the cup-shaped member and the circular front surface of the cylindrical armature, and resilient means for returning the cup-shaped member to its rest position.

Claim 3

A step-by-step drive device for a ratchet-wheel acting through a pawl, said drive device comprising a movable cylindrical cup-shaped member having a closed end mechanically connected to the pawl, a coil connected to a source of electric pulses wound on said movable cup-shaped member, a cylindrical armature of a fixed ferrite core received in said cup-shaped member, said ferrite core forming an annular magnetic field surrounding said coil, a combined guide member and sealing ring for the cup-shaped member formed as a ring of low-friction low-density material fixed to the cup-shaped member and defining a clearance of several microns between the cylindrical armature and the combined guide member and sealing ring, said combined guide member and sealing ring together with said cup-shaped member and said ferrite core defining a pneumatic dampening means for said cup-shaped member, a damping member interposed between the closed end of the cup-shaped member and the circular front surface of the cylindrical armature, and resilient means for returning the cup-shaped member to its rest position.

Claim 4

A step-by-step drive device for a ratchet-wheel acting through a pawl, said drive device comprising a movable cylindrical cup-shaped member having a closed end mechanically connected to the pawl, a coil connected to a source of electric pulses wound on said movable cup-shaped member, a cylindrical armature of a fixed ferrite core received in said cup-shaped member, said ferrite core forming an annular magnetic field surrounding said coil, a combined guide member and sealing ring for the cup-shaped member formed as a ring of low-friction low-density material fixed to the cup-shaped member and defining a clearance of several microns between the cylindrical armature and the combined guide member and sealing ring, said combined guide member and sealing ring together with said cup-shaped member and said ferrite core defining a pneumatic dampening means for said cup-shaped member, a damping member interposed between the closed end of the cup-shaped member and the circular front surface of the cylindrical armature, and resilient means for returning the cup-shaped member to its rest position.

Claim 5

A device according to claim 1, wherein the ferrite core is annular and produces the magnetic field surrounding the cup-shaped member, said pawl being fixed directly to the closed end of the cup-shaped member, and further comprising a bearing associated with an abutment, said resilient means being formed as an elastic diaphragm coaxially with and outside the cup-shaped member between the cup-shaped member and the ferrite core.

Claim 6

A device according to claim 1, wherein the pawl is connected to the closed end of the cup-shaped member through a weighted lever, one arm of the weighted lever being connected to the pawl and the other arm of the weighted lever being connected to the closed end of the cup-shaped member, said weighted lever having a counter-balancing weight, the resilient means being arranged to return the weighted lever to its centered position.

Claim 7

A device according to claim 3 wherein said weighted lever has a third arm, and said resilient means being connected to said third arm.

Claim 8

A device according to claim 3 wherein the operative effect of said resilient means on the movable components of said device provides the movable components with a vibration frequency generally corresponding with the frequency of the electric pulses.

Claim 9

A device according to claim 2 wherein the operative effect of said resilient means on the movable components of said device provides the movable components with a vibration frequency generally corresponding with the frequency of the electric pulses.

Claim 10

A device according to claim 2 wherein said resilient means is a spiral spring.

Claim 11

A device according to claim 2 wherein said resilient means is a spiral spring, said spring including inner and outer annular rings, and spiral elements joining together said rings.

Claim 12

A device according to claim 1 wherein said resilient means is a spiral spring, said spring including inner and outer annular rings, and spiral elements joining together said rings.