Spring motor operated tilting toy dump truck

Claim 1

A DUAL PISTON AND CYLINDER STRUCTURE COMPRISING TWO CYLINDERS IN RIGID COAXIAL AND COEXTENSIVE RELATIONSHIP, A PARTITION WALL SEPARATING ADJOINING INNER ENDS OF SAID CYLINDERS, END WALLS CLOSING THE OUTER ENDS OF SAID CYLINDERS, ONE OF SAID END WALLS HAVING AN OPENING PROVIDED THEREIN, A PISTON ROD EXTENDING THROUGH AND RECIPROCABLE IN SAID OPENING AND CONNECTED WITH A PISTON RECIPROCABLE IN ONE OF SAID CYLINDERS, A PISTON RECIPROCABLE IN THE OTHER OF SAID CYLINDERS, A COILED COMPRESSION SPRING IN THE LATTER CYLINDER COMPRESSIBLE BETWEEN SAID PISTON AND THE OUTER END WALL OF SAID CYLINDER, THE INNER ENDS OF SAID CYLINDERS BEING IN COMMUNICATION THROUGH OPENINGS PROVIDED IN SAID PARTITION WALL, AND CHECK VALVE MEANS COOPERATING WITH SAID OPENINGS AND HOUSED IN SAID PARTITION WALL TO CONTROL FLUID FLOW BETWEEN SAID CYLINDERS TO PROVIDE A CERTAIN FLOW RATE IN ONE DIRECTION BETWEEN SAID CYLINDERS WITH SAID CHECK VALVE MEANS SEATED AND A DIFFERENT FLOW RATE IN THE OPPOSITE DIRECTION WITH SAID CHECK VALVE MEANS UNSEATED.