Abstract: An electromagnetic clutch has a driving member and a driven member with rollers positioned between opposing non-parallel surfaces on the members. An armature operated by an electromagnet has fingers for moving the rollers into frictional engagement with the surfaces when the electromagnet is energized to engage the clutch and for moving the rollers out of engagement with at least one opposing surface when the electromagnet is deenergized to disengage the clutch.

Abstract: A power transfer mechanism incorporated in a multiple path drive system comprises a transfer case disposed between a source of input torque and a pair of drive axles. Torque is transferred directly to one drive axle and is transferred automatically to the other drive axle through a double-acting roller clutch when required. The transfer case is constructed such that it may be assembled in two configurations; one in which the output shafts are coaxial and offset from the input shaft, and the other in which the input shaft and one output shaft are coaxial, the other output shaft being offset therefrom.

Abstract: A clutch mechanism includes forward and reverse driving gears rotatably mounted on the input shaft which has first and second oppositely threaded driving spiral threads thereon. First and second clutch elements threadedly engage the spiral threads on the input shaft. In the neutral position, the clutch elements rotate with the input shaft but when rotation is impeded, the spiral threads drive the clutch elements axially into engagement with the driving gears. An improved shift mechanism includes a yoke having two legs which extend over flanges on the clutch elements. A pin member moves the clutch elements upon axial movement of the shift linkage. Drag is provided for the yoke so that the flange of the clutch element is pinched between the pin member and the yoke to impede rotation of the clutch element. The shift mechanism engages and disengages the clutch smoothly and with the engine torque providing most of the force required for engagement and disengagement.