| 摘要 |
<p>A grab excavator comprises a fixed jib mounted on said pontoon, and a grab suspended from the jib for vertical movement, whereby the grab can be lowered below the pontoon for lifting a mixture of sand and water and thereafter elevated above the pontoon for releasing the mixture. A chute mounted on the jib is pivotal between an inclined operative position beneath the grab and an inoperative position out of the path of the grab, and a feed device is located at the lower end of the chute, when the chute is disposed in the inclined operative position, for receiving the sand-water mixture therein as directed thereto by the chute. A hydraulic ram mounted on the pontoon pivots the chute between the operative and inoperative positions. The feed device includes a sieve that normally is located in a downwardly inclined position adjacent the chute and at substantially the same angle of inclination as the chute to form an extension of the chute when the chute is located in the operative position, whereby the sieve receives the sand-water mixture from the chute for processing through the feed device. An opening formed in the feed device in a wall thereof facing the chute receives the mixture of sand and water from the chute as the chute is being raised to the full operative inclined position, thereby preventing loss of fine sand that may escape from the grab before the chute is fully raised to the operative position thereof.</p> |
