Switching assembly for a hydraulic pump jack

A switching assembly for a hydraulic pump jack, said switching assembly comprising:

• (a) a non-magnetic cylinder having:
• a.1 an exterior surface and an interior surface, said interior surface defining an interior bore;
• a.2 a lower end;
• and
• a.3 an upper end that is higher than the lower end;
• (b) a piston reciprocally movable within the interior bore of the cylinder, the piston having circumferential sealing means to engage the interior surface of the cylinder;
• (c) a magnetic element carried by the piston;
• (d) a fluid source supplying a hydraulic working fluid to the cylinder, such that injection of working fluid into the cylinder will cause the piston to move toward the upper end of the cylinder;
• (e) an array of magnetically-triggered sensors mounted to the exterior surface of the cylinder at selected axially-spaced intervals, each said magnetically-triggered sensor having a unique sensor value, wherein the unique sensor value of each magnetically-triggered varies incrementally from the lower end of the cylinder to the upper end of the cylinder;
• and
• (f) a controller adapted to receive signals from the magnetically-triggered sensors;
• wherein:
• (g) the controller will receive signals from the magnetically-triggered sensors as the magnetic element carried by the piston comes in proximity with and influences the magnetically-triggered sensors as the piston moves axially within the cylinder;
• and
• (h) the controller is adapted to determine precise piston positioning within the cylinder based upon the unique sensor values of the signals received and controlling piston movement by selectively controlling the flow of working fluid from the fluid source to the cylinder.