Pneumatic drive device for a probe, particularly an eddy current measuring probe

Claim 1

A pneumatic drive device for a probe more particularly for an eddy current measuring probe, for driving said probe into a tube to be checked, comprising a tight flexible tube, a probe movable in said tube and connected to a cable, means for connecting one of the ends of said flexible tube to a pushing and pulling device for said cable, means for introducing a compressed fluid into said flexible tube between said pushing and pulling device and said probe to aid in driving said probe through said tube, and a cylinder-piston-restoring spring assembly at the other end of said flexible tube for connecting said tube to the tube to be checked comprising a rigid tube forming an extension of said flexible tube in which said probe can be moved, a cylinder around said rigid tube, said cylinder and said rigid tube defining a chamber, a piston movable in said chamber and adapted at one end to engage with the tube to be checked, a pipe connecting said chamber and said rigid tube to allow compressed fluid into said chamber and restoring springs between said piston and said cylinder, said compressed fluid engaging said piston beneath a tube to be checked and said restoring springs disengaging said piston from a tube which has been checked.