Abstract: Forming a tubular workpiece by applying fluid pressure to the interior of the workpiece and enclosing the pressurized workpiece in a die that has a die cavity. A portion or the whole of the die cavity has its internal periphery smaller than the external periphery of the workpiece. This subjects the workpiece to compressive forming.

Abstract: Apparatus for retracting and securing the grapple head (22) of a grapple skidder (10) for travel over rough terrain in an unloaded condition. A pair of cables (94, 96) of equal length are attached to the grapple head at points laterally spaced from the vertical pivot axis of the grapple head. The cables extend through a guide member (100) on the grapple arch (20) and are wound together onto a winch (24) mounted on the skidder frame (14). The guide member has a relatively large opening (106) flared outwardly and downwardly facing the grapple head, and a relatively smaller opening (108) flared outwardly and downwardly facing the winch. In normal operation of the grapple, the cables are left slack. When the grapple head is to be secured for travel, the cables are winched in. Since the cables are wound together, they retract together regardless of the relative tension in each cable, such that the grapple head automatically becomes centered square to the back of the skidder when the cables are winched in.

Abstract: An improved tree harvesting device of the swing boom type has an energy conserving drive mechanism for driving the swing boom. The energy conserving mechanism uses an energy storing means located between a prime mover and the swing boom; the energy storing means stores the energy dissipated by the swing boom when stopping.