HERMETICALLY SEALED ARTIFICIAL LEG

摘要

This invention relates to a technique for hermetically sealing an artificial leg including a cylinder device. A shell structure surrounds the outside of the cylinder device. The cylinder device is not entirely received within the shell structure, but a rod member extends to the outside of the shell structure from the cylinder body within the shell structure and a part of the rod member is located outside the shell structure. In this invention, the rod member, which extends from the inside to the outside of the shell structure, is hermetically sealed at the periphery thereof by a bellows packing member. The bellows packing member comprises an inner bead, an outer bead which concentrically surrounds the outside of the inner bead, and a bellows packing body part which connects the inner and outer beads. The bellows packing body part includes corrugations, and each corrugation is less curved than an imaginary circle formed between the outer bead and the inner bead and is configured in such a manner that both ends of the corrugation reach the outer bead or are located at positions closer to the outer bead than the inner bead.

主权项

1. An hermetically sealed artificial leg comprising
an upper member for supporting a socket at an upper end thereof, a lower member for supporting a foot part at a lower end thereof, a knee coupling for bendably coupling said upper and lower members, a cylinder device for assisting and/or limiting movement of said knee coupling, a shell structure for surrounding an outside of said cylinder device, said cylinder device including a cylinder body having an axis, and a rod member extending in a direction of said axis from said cylinder body, said rod member extending from inside of said shell structure to outside thereof, and, a bellows packing member for hermetically sealing a periphery of said rod member, wherein said bellows packing member includes: an inner bead defining a hole for receiving said rod member therein and serving as a sealing portion for an inner periphery of said bellows packing member; an outer bead serving as an attachment part to a side of said shell structure and also serving as a sealing portion for the side of said shell structure; and, a bellows packing body part which is a body portion located between said inner and outer beads and which has a plurality of corrugations aligned with each other and which is capable of varying a distance between said inner and outer beads, and wherein each of said corrugations is less curved than an imaginary circle between said inner and outer beads and both ends of said corrugation reach the outer bead or are located at positions closer to the outer bead than the inner bead.