Abstract: A tandem exerciser is described with two facing seats and two pedal cranks that cause tandem riders to face each other and pedal forwards. A mutually operable handlebar crank with opposing handles mechanically couples to pedals on both sides of the distal pedal crank. A single sprocket wheel concentrically attached to the proximal pedal crank is coupled by a twisted, figure-eight looped chain to one of two sprocket wheels coupled to the distal pedal crank. These opposing sprocket wheels are mounted to their respective pedal cranks so as to have opposite offset angles relative to vertical plane of frame. These offset angles prevent damaging physical contact between sides of chain. The remaining sprocket wheel of distal pedal crank is conventionally chain coupled to freewheel coupled to hub of flywheel. Optionally, a power generator is belt-coupled to outer rim of flywheel, to produce electrical, fluidic or motive power.

Abstract: A tandem exerciser is described with two facing seats and two pedal cranks that cause tandem riders to face each other and pedal forwards. A mutually operable handlebar crank with opposing handles mechanically couples to pedals on both sides of the distal pedal crank. A single sprocket wheel concentrically attached to the proximal pedal crank is coupled by a twisted, figure-eight looped chain to one of two sprocket wheels coupled to the distal pedal crank. These opposing sprocket wheels are mounted to their respective pedal cranks so as to have opposite offset angles relative to vertical plane of frame. These offset angles prevent damaging physical contact between sides of chain. The remaining sprocket wheel of distal pedal crank is conventionally chain coupled to freewheel coupled to hub of flywheel. Optionally, a power generator is belt-coupled to outer rim of flywheel, to produce electrical, fluidic or motive power.

Abstract: A fuel filter is provided for internal combustion engines and particularly for diesel engines utilizing a dual filter zone arrangement fed by two separate fuel supply lines, each of these lines being valved to operate in an open mode in which fuel is pumped freely from the fuel tank into the filter zone, and a dump mode, wherein reverse-flow fuel delivered from the other filter zone backwashes the dumping filter zone to purge the filter elements of accumulated particulates.