Patent ID: 8371210
Filing Date: 2013-02-12
Classification: F01B,F02B,F16H,Y10T

Abstract:
1. A scotch yoke fluid device selected from an engine and a pump including: a crankshaft having a main axis and having a big end bearing pin which has a big end bearing pin axis, the crankshaft adapted for rotation about the main axis and the big end bearing pin being adapted to orbit the main axis during crankshaft rotation, the big end bearing pin adapted to sweep a first volume as it orbits the main axis; connecting means rotatably mounted on the big end bearing pin and adapted to orbit the main axis during crankshaft rotation; a cylinder having a cylinder axis, the cylinder axis being perpendicular to the main axis; a piston having a piston axis and including: (a) a piston crown having a cross sectional area perpendicular to the piston axis; (b) first guide means elongate along an axis extending perpendicular to the piston axis; (c) second guide means elongate along an axis extending parallel to the piston axis and having a first end and a second end; the piston mounted for reciprocation along the piston axis; a second volume defined by a projection of the piston crown cross sectional area along the piston axis in the direction of the crankshaft the first guide means being located only to that side of the big end bearing pin axis lying between the big end bearing pin axis and the piston crown; the first guide means engaging the connecting means whereby the connecting means is constrained to reciprocate along the first guide means during crankshaft rotation; a component selected from a crank case and a block including third guide means adapted to engage the second guide means, the second guide means and the third guide means cooperating to substantially prevent rotation of the piston around an axis parallel to the main axis; wherein: (i) the second guide means and the third guide means are located such that they are in engagement only within the second volume; (ii) the second guide means is positioned to a side of the first guide means, the first end of the second guide means is located closer to the piston crown than is the first guide means, and when the piston is at TDC the second end of the second guide means is located closer to the big end bearing pin axis than is the first guide means; and (iii) the second guide means is adapted to be moved in and out of the first volume during crankshaft rotation such that the second guide means is outside the first volume when the piston is at TDC.