Patent ID: 8245627
Filing Date: 2012-08-21
Classification: F01B,F02B,F16J,Y10T

Abstract:
1. A scotch yoke engine or pump includes a block, a crankshaft having a main axis and including an offset big end bearing pin, a slider mechanism mounted for rotation on the bearing pin, a piston having a piston axis, a yoke structure including first guide means which is elongate along an axis extending perpendicular relative to the piston axis, the first guide means engaging the slider mechanism and constraining the slider mechanism to reciprocate along the first guide means, the yoke structure including second guide means for constraining the yoke structure to reciprocate along the piston axis, the second guide means engaging third guide means, the engagement of the second guide means with the third guide means being such that the yoke structure is prevented from rotating around an axis parallel to the main axis, the piston and the yoke structure being separate units; the piston having a crown and a base surface opposite the crown; the yoke structure having an end facing the piston base; the end of the yoke structure and the piston base having respective bearing surfaces; the bearing surfaces being members of a flat bearing joint which also includes a flying key, the flying key having an upper key element which engages a cooperating key element of the piston base, the flying key having a lower key element which engages a cooperating key element of the yoke end, the piston and the yoke structure being connected together such that the piston is prevented from rotating relative to the yoke structure but is allowed to move relative to the yoke structure along a path defined by the upper key element, and the flying key is free to move relative to the yoke structure along a path defined by the lower key element, during engine operation.