Patent ID: 6561142
Filing Date: 2003-05-13
Classification: F01B,F02B

Abstract:
A crank mechanism of a reciprocating internal combustion engine having a piston, comprising:a crankshaft including paired crank webs with first end portions connected through a crank pin, and paired counterweights integral with second end portions of the paired crank webs, said paired counterweights having projected inner surfaces which protrude toward each other defining a given space therebetween; a link mechanism including a plurality of links between the piston and the crankshaft which are arranged to convert a reciprocating motion of said piston to a rotational motion of the crankshaft, a given one of said links being pivotally connected to other links through link connecting portions and swingably disposed on said crank pin so that upon rotation of said crankshaft, a peripheral portion of said given link passes through said given space, wherein at least one of said link connecting portions is placed within an imaginary circle which would be described as being centered about an axis of said crank pin and having a radius substantially equal to the distance between the radially innermost part of said projected inner surfaces of the paired counterweights and the center of said crank pin.