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:
Jul. 06, 1976
Filed:
Aug. 05, 1974
Carlo Grandori, Rome, IT;
The Robbins Company, Seattle, WA (US);
Abstract
Front and rear shields are telescopically joined together. The front shield carries a power driven rotary cutterhead means. Main 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 groups of auxiliary thrust rams which extend rearwardly from the rear shield to contact forward end portions of a tunnel lining which is erected under cover of a tail section of the rear shield. The auxiliary thrust rams are extendable a distance that is at least slightly larger than the axial length of one ring of tunnel lining segments. The main thrust rams are extendable a distance that is slightly larger than 1x of the stroke of the auxiliary thrust rams, where x is the number of groups of auxiliary thrust rams. Each group of auxiliary thrust rams is offset from an adjacent group an amount equal to the stroke of the main thrust rams.