Instrument for the extraction of kidney stones

Claim 1

IN AN INSTRUMENT FOR THE EXTRACTION OF KIDNEY STONES HAVING A BASE, A FLEXIBLE TUBE ATTACHED TO THE BASE, A SINGLE FLEXIBLE WIRE EXTENDING THROUGH THE TUBE, AND MEANS AT THE BASE OF MOVING THE WIRE ENDWISE IN BOTH DIRECTIONS, THE IMPROVEMENT IN A TIP ASSEMBLY IN COMBINATION THEREWITH COMPRISING A HEAD MOUNTED ON AN END OF THE TUBE REMOTE FROM THE BASE, A TIP MOUNTED ON THE OUTER END OF SAID HEAD AND DEFINING THEREIN A FIRST CHAMBER ADJACENT SAID HEAD AND A SECOND CHAMBER AT THE ENDMOST PORTION OF THE TIP, SAID TIP BEING FORMED FROM AN INTEGRAL PIECE OF RESILIENT METAL SUCH AS BERYLLIUM COPPER AND SUBDIVIDED INTO A PLURALITY OF JAWS BY CUTS EXTENDING INWARDLY FROM THE ENDMOST PORTION OF THE TIP INTO THE FIRST CHAMBER SO THAT JAWS CAN BE SPRUNG APART AND WILL RESILIENTLY RETURN TO THEIR CLOSED POSITION, INTERNAL PROJECTIONS ON SAID JAWS EXTENDING INWARDLY BETWEEN THE FIRST AND SECOND CHAMBERS WHICH ARE PROVIDED WITH A CAM SURFACE PARTLY DEFINING THE FIRST CHAMBER, AND MEANS ON THE END OF SAID WIRE POSITIONED IN THE FIRST CHAMBER FOR CONTACTING THE CAM SURFACE ON MOVING THE WIRE TOWARD THE TIP AND SPRING THE JAWS APART BY CAM ACTION.