Crank assembly for reciprocating piston machines

In a machine having a plurality of pistons mounted to travel along radially arranged axes, the improvement comprising:

• (a) a main crank rotatable about a main crank axis and having a crank pin with a crank pin axis;
• (b) a plurality of connecting rods each having an outer end and an inner end, the outer ends being connected to pistons;
• (c) an articulation member interconnecting the main crank and the inner ends of the connecting rods and being journaled by the crank pin for movement about the crank pin axis;
• (d) means constraining the articulation member to motion in which lines therein remain parallel to each other during such motion;
• (e) the constraining means consisting of two auxiliary cranks each having the same crank radius as the main crank, each being arranged parallel thereto, and each having:
• (i) a portion rotatable about a separate fixed axis, the fixed axis extending in parallel non-coplanar relationship with the main crank axis;
• and,
• (ii) a radially displaced portion carrying a crank pin pivotally connected to the articulation member.

In a machine of the type having a body, a crankshaft journaled by the body for rotation about a crankshaft axis, a crank pin carried on the crankshaft and having a center axis and a plurality of connecting rods, the improvement of a crank assembly for drivingly coupling the connecting rods to the crank pin, comprising:

• (a) an articulation member journaled on the crank pin for movement about the axis of the crank pin;
• (b) connecting means for pivotally connecting the connecting rods to the articulation member;
• (c) constraining means interconnecting the articulation member and the body of the machine for confining freedom of movement of the articulation member and for preventing it from rotating as it travels with the crank pin in a circular path about the crankshaft axis;
• (d) the constraining means consisting of two auxiliary cranks each having one shaft portion journaled by the body for rotation about separate auxiliary crank axes, and a crank portion carrying an auxiliary crank pin having an auxiliary crank pin axis, the auxiliary crank pins being journaled by the articulation member;
• (e) the distances between the auxiliary crank axis and the auxiliary crank pin axis of each auxiliary crank being equal to the distance between the crankshaft axis and the center axis;
• and,
• (f) the auxiliary crank pin axes being arranged such that a line connecting the center axis and one of the auxiliary crank pin axes makes an angle with a line connecting the center axis with the other of the auxiliary crank pin axes, and said angle is sufficiently greater than zero and sufficiently less than 180 degrees to prevent a dead center condition of the auxiliary cranks with respect to the main crank.

In a machine having a plurality of pistons mounted to travel along radially arranged axes, the improvement, comprising:

• (a) a main crank having a crank pin with a crank pin axis;
• (b) a plurality of connecting rods each having an outer end and an inner end, the outer ends being connected to pistons;
• (c) an articulation member interconnecting the main crank and the inner ends of the connecting rods and being journaled by the crank pin;
• (d) means constraining the articulation member to motion in which lines therein remain parallel to each other during such motion;
• (e) the constraining means consisting of two auxiliary cranks each having the same crank radius as the main crank, each being arranged parallel thereto, and each having:
• (i) a portion rotatable about a separate fixed axis;
• and,
• (ii) a radially displaced portion carrying an auxiliary crank pin pivotally connected to the articulation member, the auxiliary crank pin interconnecting the radially displaced portion and the articulation member for relative movement about a separate auxiliary axis;
• and,
• (f) the auxiliary axes and the crank pin axis extending in parallel, non-coplanar relationship.