| 摘要 |
A tubular device for advancing a medical treatment or examination instrument in a tubular passageway and having a head portion with outwardly biassed, rearwardly extending, flexible legs and a tail portion with outwardly biassed, rearwardly extending, flexible legs. The head and tail portions are interconnected by a fluid extensible bellows, and alternate expansion and contraction of the bellows causes advance of the head and following motion by the tail, the legs engaging the passageway wall and permitting forward motion but preventing backward motion through the passageway. In one embodiment of the device the head and tail parts are generally cylindrical and relatively rigid. In another embodiment, the head and tail portions each has extensible bellows arranged within a deformable cage constituted by jointed, flexible legs arranged to project outwardly to engage the passageway wall when the bellows they surround is contracted. The actuating fluid can be air supplied and withdrawn through a flexible tube or tubes communicating with the bellows and advancing with the device.
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