Calculus crushing apparatus

Claim 1

A crushing apparatus for crushing a calculus produced in a body cavity, comprising: a flexible sheath having a proximal end and a distal end and including a rigid portion at the distal end and adapted to be inserted into the body cavity; an operating wire longer than the sheath and slidably inserted into the sheath and having a proximal end portion and a distal end portion; a collapsible basket for seizing the calculus, said basket including a plurality of elastic wires coupled to the distal end portion of the operating wire and extending from the distal end of the sheath; a body removably connected to the proximal end of the sheath; a rack slidably arranged in the body and coupled to the proximal end portion of the operating wire, to be slidable together with the operating wire; and first and second operating means for selectively sliding said rack and thereby sliding said operating wire relative to said sheath so as to expand or contract said basket; said first operating means including a handle grip portion connected to said rack and extending outwardly from the body for sliding said rack directly by hand; said second operating means including an operating handle mounted on said body so as to be freely rotatable with respect to and unobstructed by said body, and also including a speed reduction and force amplifying mechanism including a plurality of meshing gears of different sizes interposed between said operating handle and said rack such that a rotary speed and a rotary force applied to said operating handle are transmitted to said rack and thereby to said operating wire as a reduced speed and an amplified force, respectively.