Patent ID: 7647963

Claim:
A polish rod device providing an elongated member for interconnecting a petroleum well sucker rod string to a wellhead primary cable at one end while supporting the mass of the string, and petroleum product, and withstanding frictional and inertial forces, and comprising: a cylindrical polish rod having a nominal diameter of greater cross-sectional area than the sucker rods in the string and adapted to couple at its upper end to the primary cable, the lower end of the polish rod terminating in a length of untapered thread and including an adjacent pin neck terminating at its upper end at a transverse plane, a seating length of polish rod adjacent the transverse plane on the upper side thereof and having a diameter that is smaller by a predetermined amount that the nominal diameter of the polish rod, and said seating length terminating in a shoulder abutting the principal body of the polish rod; and an outer sleeve mounted with a shrink fit on the seating length of the polish rod from the transverse plane to the curved shoulder, the sleeve providing a shoulder at the transverse plane.