Importance

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Abstract

A gas injection valve comprises a valve casing fitted to a gas bottle, a valve pin slidably received in the valve casing, first and second seal rings fitted to the inner peripheral wall of the valve casing, and a fixed-quantity chamber defined between the first and second seal rings for capturing therein a fixed amount of gas before injection. The valve pin has a gas passage bore for intercommunicating a first port formed in the upper face of the tip of the valve pin and a second port formed in the outer peripheral wall of the valve pin. The second port is located to open into the substantially cylindrical hollow of the casing above the second seal ring with the valve pin kept in a lifted-up position and to open into the fixed-quantity chamber below the second seal ring during one-step pushing action and two-step pushing action of the valve pin. A first bypass portion is formed in the valve pin for intercommunicating the interior of the gas bottle and the fixed-quantity chamber through a partial space of the substantially cylindrical hollow near the first seal ring in the lifted-up position of the valve pin. A second bypass portion is formed in the valve pin for intercommunicating the interior of the gas bottle and the fixed-quantity chamber through the partial space of the substantially cylindrical hollow near the first seal ring only during the two-step pushing action.

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First Claim