Counterbalance means

Claim 1

A PUMP JACK MECHANISM INCLUDING: A SUPPORT; A ROTATABLE DRIVE SHAFT CARRIED BY SAID SUPPORT; A POWER TRANSMISSION UNIT MOUNTED ON SAID DRIVE SHAFT AND SWINGABLE IN AN ARC ABOUT SAID DRIVE SHAFT; SAID TRANSMISSION UNIT HAVING A DRIVEN SHAFT SPACED FROM THE DRIVE SHAFT AND DRIVEN THROUGH SAID POWER TRANSMISSION UNIT BY SAID DRIVE SHAFT; A HOUSING FOR SAID TRANSMISSION UNIT SUPPORTING SAID DRIVEN SHAFT IN SPACED RELATIONSHIP WITH RESPECT TO SAID DRIVE SHAFT; A CRANK ARM SECURED TO SAID DRIVEN SHAFT AND SWINGABLE ABOUT THE AXIS OF SAID DRIVEN SHAFT THROUGH A CIRCULAR PATH AND THROUGH AN ARCUATE PATH WITH THE HOUSING ABOUT THE AXIS OF THE DRIVE SHAFT; AN ELONGATE WALKING BEAM SUPPORTED INTERMEDIATE ITS ENDS AT A FIXED POINT ON SAID SUPPORT FOR PIVOTAL RECIPROCATING MOVEMENT ABOUT SAID FIXED POINT ON SAID SUPPORT IN A SUBSTANTIALLY VERTICAL PLANE, ONE END OF SAID WALKING BEAM BEING ADAPTED TO BE CONNECTED TO A RECIPROCABLY MOVABLE VERTICAL LOAD; A MECHANICAL LINKAGE CONNECTING SAID CRANK ARM WITH ONE LEVER ARM PORTION OF SAID WALKING BEAM FOR EFFECTING RECIPROCATING MOVEMENT OF SAID WALKING BEAM UPON ROTATION OF SAID DRIVE SHAFT; SAID LINKAGE COMPRISING AN AUXILIARY BEAM MEMBER PIVOTALLY MOUNTED AT ONE END ON SAID SUPPORT AT A POINT SPACED SUBSTANTIALLY VERTICALLY BELOW SAID FIXED POINT FOR SWINGABLE OSCILLATION IN A SUBSTANTIALLY VERTICAL PLANE ABOUT SUCH PIVOTAL CONNECTION WITH SAID SUPPORT; A CONNECTING LINK MEMBER PIVOTALLY CONNECTED AT ONE END TO THE END OF THE WALKING BEAM OPPOSITE SAID RECIPROCABLY MOVABLE LOAD AND AT ITS OTHER END TO SAID AUXILIARY BEAM ADJACENT ITS OUTER SWINGABLE END, SAID LINK MEMBER CONNECTING SAID ELONGATE WALKING BEAM AND SAID AUXILIARY BEAM PARALLEL TO EACH OTHER, WHEREBY SAID ELONGATE WALKING BEAM IS SWINGABLE ABOUT ITS PIVOTAL MOUNTING INTERMEDIATE ITS ENDS BY SAID AUXILIARY BEAM; CONNECTING MEANS OPERATIVELY INTERCONNECTING THE SWINGABLE END OF SAID CRANK ARM AND SAID AUXILIARY BEAM, WHEREBY THE SWINGABLE END OF SAID CRANK ARM IS CONNECTED WITH SAID ELONGATE SWINGABLE WALKING BEAM OPPOSITE THE END OF SAID WALKING BEAM TO WHICH SAID LOAD IS ADAPTED TO BE CONNECTED FOR CAUSING RECIPROCATING OSCILLATING MOVEMENT OF SAID WALKING BEAM UPON ROTARY MOVEMENT OF SAID CRANK ARM BY SAID DRIVE SHAFT; AND COUNTERBALANCE WEIGHT MEANS ON SAID CRANK ARM OUTWARDLY OF SAID CRANK ARM FROM SAID DRIVE SHAFT BEYOND THE CONNECTION OF SAID CRANK ARM WITH SAID AUXILIARY BEAM AND SWINGABLE THEREWITH FOR IMPOSING A TORQUE UPON SAID LINKAGE AND SAID WALKING BEAM.