Patent ID: 6698844
Filing Date: 2004-03-02
Classification: E21D

Abstract:
An earth discharging device for an upward-facing shield machine comprising: an earth discharging pipe which is disposed vertically in order to discharge downward earth and sand which are excavated by an upward-facing shield machine that advances upward; an elastic film-type valve which is provided in said earth discharging pipe, and which opens and closes the interior of the earth discharging pipe by expanding and contracting diametrically by means of fluid pressure; and a gate mechanism made from a rigid body, which is provided further toward the outlet side of the earth discharging pipe than said elastic film-type valve, and which adjusts the sectional area of the space in the earth discharging pipe through which earth and sand pass, said gate mechanism narrowing the sectional area of the earth discharging pipe adjacent said elastic film-type valve by expanding said elastic film-type valve in response to said gate mechanism closing a predetermined amount and thereby causing pressure within said earth discharge pipe between said elastic film-type valve and said gate mechanism to rise so as to cause uniform pressure to act upon either side of said elastic film-type valve, wherein said elastic film-type valve expands substantially uniformly.