| 摘要 |
PROBLEM TO BE SOLVED: To widen a hole peripheral wall by uniform force of hydraulic pressure, and to gradually expand and widen a small hole by wrench-opening the small hole. SOLUTION: Slotted grooves and horizontal holes are provided in several places in a tip part of a base body 4 for fixing a hydraulic cylinder 5, a rod having two or more conical wedge pieces is connected to the poston rod tip, several pushing-away materials are formed as a female shape part having the inside adapted to the wedge pieces, and an external part is contracted in the center by a coil spring 9 arranged in the several grooves. End parts of the pushing-away materials have a crevice 16 having an elongate hole, and are inserted into a slotted part, and can freely rotate and sideslip with the base body by a pin 7. The tip of a wrench-opening pushing-away material is formed in a multistage shape of a taper and a stairs shape. Widening force can be strongly exhibited on average in the direction of three or more surfaces of a peripheral wall of the hole. This widening tool having a tapered part has an effect as a rescue tool for a person shut in a certain space. Since the number of part items is reduced, failure is reduced.
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