Hydraulic Packless Pump Jack for Oil Wells (Patent No: 586428)

Inventor: Cunningham, Stanley S.

Location: Calgary

Comments: N/A

Description: Issued November 3, 1959.

Stanley S. Cunningham, Calgary, Alberta, Canada. Application January 11, 1954, Serial No. 659,545.
3 Claims.

1. A fluid motor adapted to be actuated by a source of power, comprising in combination a piston rod supporting casting, a pair of hollow-piston rods secured by one end thereof to and extending from said casting, a piston on the other end of each of said piston rods, the interior bores of said piston rod's communicating with the upper surfaces of said pistons, a twin cylinder assembly mounted for reciprocation upon said pistons and said pistons rods, and means selectively controlling connection between said source of fluid power and said first-mentioned end of said hollow piston rods, said means including a fluid valve actuated by reciprocation of said twin cylinder assembly, and piston rod tube surrounding said piston rods and being secured by one end thereof to said casting and by the other end thereof to said piston.

2. The device according to claim 1 which includes means to control the length of stroke of said twin cylinder assembly, between limits.

3. The device according to claim 2 in which said means to control the length of stroke of said cylinders within limits includes an hydraulic valve secured adjacent to said piston rod supporting casting, a trip rod and piston extending upwardly from said valve and adapted to actuate the latter, a cylinder surrounding said trip rod and piston, said cylinder being secured to said twin cylinder assembly, and an adjustable screw cap within the upper end of said trip rod cylinder for varying the effective length of the stroke of said trip rod.