Flexible coupling means and a mechanical transmission

A coupling for accommodating axial and radial alignment variations between two rotary parts, the coupling comprising:

• a first coupling member provided with a first diaphragm and connected to a first rotary part;
• a second coupling member provided with a second diaphragm and connected to a second rotary part, wherein the first and second diaphragms are secured together to provide a connection allowing axial and/or angular and/or lateral offset between the first and second rotary parts;
• and
• a back-up torque-transmission emergency device for connecting the first rotary part to the second rotary in the event of a failure of the connection provided by the first and second diaphragms, wherein the emergency device includes:
• a protuberance extending from the first coupling member;
• and
• an angled groove disposed on the second coupling member for co-operating with the protuberance, wherein the angled groove is sized to provide axial and angular clearance when the protuberance is inserted in the angled groove,
• wherein the protuberance is inserted in the angled groove by a thrust movement and a rotation movement so that the protuberance is contained within the groove and is prevented from being removed from the groove in an axial direction,
• wherein the back-up torque-transmission emergency device secures the first and second rotary parts together in the axial direction while allowing both axial clearance in compression together with axial clearance in traction and also angular clearance between each of the first and second rotary parts.

A coupling member for accommodating axial and radial alignment variations between two rotary parts, the coupling member comprising:

• a first rotary part provided having a first diaphragm;
• a second rotary part provided having a second diaphragm, wherein the first and second diaphragms are secured together and provide a connection allowing axial and/or angular and/or lateral offset between the first and second rotary parts;
• and
• a back-up torque-transmission emergency device for connecting the first rotary part to the second rotary, wherein the emergency device includes:
• a protuberance extending from one of the first and second rotary parts;
• and
• a L-shaped angled groove disposed on the other of the first and second rotary parts for co-operating with the protuberance, wherein the L-shaped angled groove is defined by a longitudinal slot connected to a circumferential slot,
• wherein the protuberance is inserted in the L-shaped angled groove first by a thrust movement in a longitudinal direction that inserts the protuberance into the longitudinal slot, and second by a rotational movement that moves the protuberance into the circumferential slot so that the protuberance is contained within the circumferential slot and is prevented from being removed from the groove in an axial direction, thereby providing a back-up connection in the event of a failure of the connection provided by the first and second diaphragms,
• wherein during normal operation of the first and second diaphragms, the L-shaped angled groove is sized to provide axial and angular clearance with the protuberance so that the diaphragms maintain the axial and/or angular and/or lateral offset between the first and second rotary parts.