The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 13, 1983
Filed:
Nov. 27, 1981
Richard J Robbins, Seattle, WA (US);
David T Cass, Seattle, WA (US);
The Robbins Company, Kent, WA (US);
Abstract
Front and rear shields are telescopically joined together. The front shield carries a power driven rotary cutterhead means. Thrust rams are provided between the two shields for pushing the forward shield forwardly relative to the rear shield while the cutterhead means is being operated to mine the tunnel face, and also to pull the rear shield forwardly relative to the front shield. The rear shield includes a gripper assembly for reacting thrust and torque and a plurality of auxiliary thrust rams which extend rearwardly from the rear shield to react against forward end portions of a tunnel lining which is erected under cover of a tail section of the rear shield. A pair of side placed torque cylinders are interconnected between frame portions of the two shields and serve to transmit counter-rotational torque from the cutterhead support of the front shield back to the rear shield. The torque cylinders are adapted to accommodate relative axial movement between the two shields and are operable to roll the shields back into proper position after they have been rolled out of position by the counter-rotational torque generated by rotation of the cutterhead means.