Patent ID: 7168169

Claim:
A reciprocating drive apparatus comprising; a housing; a drive shaft rotatably mounted in said housing; an elongated spindle mounted in said housing for reciprocating motion, said spindle having a receiver at a first end thereof configured to engage a wobble plate interface structure; a wobble plate assembly mounted on said shaft and having an elongated arm with a wobble plate interface structure for engaging said spindle receiver; said interface structure comprising first and second ball-type interfaces concentrically aligned with each other, said first interface causing reciprocating motion of said spindle and said second interface preventing rotation of said spindle; wherein said first ball-type interface has a larger circumference than said second ball-type interface and said second interface is located at the outer end of said wobble plate assembly; said spindle receiver further comprising a first generally cylindrical opening oriented transversely of the length of the spindle configured to receive said first ball-type interface, said first interface contacting the inside surface of said opening of said receiver in a point contact relationship during reciprocation of said spindle; said spindle receiver defining an elongated slot with side walls extending outwardly from said cylindrical opening, said slot having its length oriented in the direction of reciprocating of said spindle, said second ball-type interface reciprocating in said slot during reciprocation of said spindle, the diameter of said second ball-type interface being slightly smaller than said slot width so that said second interface contacts said slot side walls in a point contact relationship during reciprocation of said spindle.