Patent ID: 7980274

Claim:
A rotary dobby for a loom, comprising for each heddle frame lifting unit: a swinging part coupled to a heddle frame and associated with an actuator element mounted loosely on a main shaft of the dobby, a drive element mounted to rotate with the main shaft, two controlled latches for coupling the drive element and the actuator element in rotation, each latch being mounted on the actuator element, a first latch, of the two controlled latches, being provided with a first bearing surface for selectively bearing against at least one corresponding first surface of the drive element, these first surfaces forming an interface for transmitting a driving force from the drive element to the actuator element, a second latch, of the two controlled latches, being provided with a second bearing surface for selectively bearing against at least one corresponding second surface of the drive element, these second surfaces forming an interface for transmitting a return force from the actuator element to the drive element, first resilient bias means for resiliently biasing each of the first and second latches towards a configuration in which their respective bearing surfaces are engaged with the corresponding surfaces of the drive element, control means for moving the at least the first latch against a force exerted thereon by the first resilient bias means, and wherein the first resilient bias means only acts directly on the first latch and indirectly on the second latch to urge the first and second bearing surfaces of the first and second latches into engagement with the corresponding first and second surfaces of the drive element and wherein the control means moves the first latch against the force of the first resilient bias means to disengage the first bearing surface from the corresponding first surface of the drive element, while the second latch remains in a position in which its second bearing surface is engaged with the second corresponding surface of the drive element.