Patent ID: 7143888

Claim:
A combined no-back and torque apparatus for limiting back-drive and limiting output torque of an actuator system, comprising: an input section that comprises a first set of rotational input section drive tangs coupled directly to an input drive shaft and a second set of rotational input drive tangs coupled to the input drive shaft through a preloaded torsional spring mechanism; a pilot section coaxially mounted with the input section that comprises a set of rotational pilot section drive tangs that selectively engage the first set of rotational input section drive tangs, a first compression brake pack and a first ball ramp; and an output section coaxially mounted with the input and pilot sections that comprises a set of rotational output section drive tangs coupled to an output collar that selectively engage the second set of input section drive tangs, a second compression brake pack mounted adjacent to the first brake pack and a second ball ramp coupled to the first ball ramp by way of a set of ramp balls; wherein application of torque to the input shaft with an opposing load coupled to the output collar causes the first and second input section tangs to engage the pilot section tangs and output section tangs, respectively, to move the output collar; wherein application of torque to the input shaft with an aiding load coupled to the output collar the first set of input tangs contact the pilot section tangs to rotate the first brake pack and the first ball ramp relative to the second ball ramp to reduce compression between them sufficiently to permit the output collar to move under load; wherein application of a load to the output collar with no torque applied to the input shaft rotates the second ball ramp relative to the first ramp, thereby rolling the ramp balls between them to compress the first and second brake packs against each other sufficiently to stop further rotation of the output collar; and wherein application of torque to the input shaft that exceeds the preload of the spring mechanism causes the first set of input section tangs to rotate less than the second set of input section tangs, thereby causing the first ball ramp to rotate relative to the second ball ramp, thereby rolling the ramp balls between them to compress the first and second brake packs against each other sufficiently to stop further rotation of the output collar.