A drive shaft which includes a first tube body having one or more first body channels defined through a wall thickness thereof. The one or more channels are configured to increase bending and/or axial flexibility of the first tube body while only allowing for a less than proportional reduction in torsional stiffness of the first tube body. A second tube body can be concentrically disposed relative to the first tube body and connected to the first tube body at a first end portion and a second end portion. The second tube body can include one or more second body channels defined through a wall thickness thereof. The one or more channels are configured to increase bending and/or axial flexibility of the second tube body while only allowing for a less than proportional reduction in torsional stiffness of the second tube body.

A drive system has a gearbox, comprising a passage therethrough, a coupling shaft disposed at least partially within the passage and a first coupling carried by a first end of the coupling shaft. The first coupling is configured to accommodate misalignment. The drive system also has a second coupling carried by a second end of the coupling shaft. The second coupling is also configured to accommodate misalignment.

A driving force transmission system for an engine is provided with a crank sprocket mounted on a crankshaft, cam sprockets mounted on camshafts, an intermediate shaft disposed between the crankshaft and the camshafts, a dual sprocket mounted on the intermediate shaft, and including a first sprocket and a second sprocket facing each other in a state that the first and second sprockets are rotatable relative to each other, a first endless transmission member wound around the crank sprocket and the first sprocket, and a second endless transmission member wound around the cam sprocket and the second sprocket. The dual sprocket includes a damping portion for connecting the first and second sprockets. The damping portion is configured to exert a resilient force in a rotational direction of the first and second sprockets.

A belt pulley arrangement with a belt pulley that is fastenable to rotate on a shaft, a torsion spring arranged within the belt pulley for enabling a transmission of torque between the belt pulley and shaft. The torsion spring acts with one end against the shaft and with an other end against the belt pulley. A looped flat spiral spring is arranged radially between the belt pulley and the torsion spring and acting as a free-running clutch. The torsion spring is arranged on one of its axial ends in a first sleeve that is connected so that it can rotate with a radial inner lateral surface of the belt pulley. The looped flat spiral spring is arranged radially between the first sleeve and the torsion spring, and contacts, in its extended state, at least in some sections on the inner lateral surfaces of the first sleeve and belt pulley.

Elastomer members for a torsional vibration damper, methods of making the same, and torsional vibration dampers having the elastomer members are disclosed. The elastomer members have a first major surface and an opposing second major surface with opposing side joining the first major surface to the second major surface, have a median sagittal plane extending parallel to the first major surface and the second major surface, and a transverse plane perpendicular to the median sagittal plane. In a cross-sectional geometry in a plane bisecting the median sagittal plane and the transverse plane, a thickness of the elastomer member changes along the median sagittal plane in a direction parallel to the transverse plane with a first thickness at both opposing sides and a second thickness at the transverse plane, where the second thickness is greater than the first thicknesses.

The present invention includes an aircraft drive system comprising a main rotor gearbox comprising a first and a second input; a first drive system comprising a first engine reduction gearbox connecting a first engine to the first input of the main rotor gearbox at a reduced shaft speed; and a second drive system independent from and redundant with the first drive system, the second drive system comprising a second engine reduction gearbox connecting a second engine to the second input of the main rotor gearbox at the reduced shaft speed.

The present invention includes an aircraft drive system comprising a main rotor gearbox comprising a first and a second input; a first drive system comprising a first engine reduction gearbox connecting a first engine to the first input of the main rotor gearbox at a reduced shaft speed; and a second drive system independent from and redundant with the first drive system, the second drive system comprising a second engine reduction gearbox connecting a second engine to the second input of the main rotor gearbox at the reduced shaft speed.

A transport system includes, in a first environment, a driving screw having threads with a thread pitch. In a second environment, a driven member has a magnetic coupling with a driven member pitch substantially corresponding to the thread pitch. The magnetic coupling is coupled to a portion of threads and rotation of the driving screw displaces the magnetic coupling with respect to the driving screw.

A transport system includes, in a first environment, a driving screw having threads with a thread pitch. In a second environment, a driven member has a magnetic coupling with a driven member pitch substantially corresponding to the thread pitch. The magnetic coupling is coupled to a portion of threads and rotation of the driving screw displaces the magnetic coupling with respect to the driving screw.

A composite driveshaft includes a body having a first end, a second end, and an intermediate portion defining a driveshaft axis (DSA). The first end defines a first coupling region and the second end defines a second coupling region. At least one of the first and second coupling regions defines a virtual hinge configured to accommodate both bending moments and axial changes of the body.