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:
Sep. 04, 1990
Filed:
Feb. 02, 1989
Franz-Josef Puttmann, Lennestadt, DE;
Alfons Hesse, Lennestadt, DE;
Paul Schmidt, Lennestadt, DE;
Abstract
A ram boring machine having a pull-and-turn reversing gear which comprises a striking piston axially displaceable in a tubular housing and a rotatably mounted control pipe with control openings such that forward and backward movement of the machine is controlled by moving the control openings over corresponding radial control openings in the striking piston, the control pipe having at least two parts with the rear part (viewed in the ramming direction) being connected to a supply hose, being relieved of the working pressure, and being connected to the bearing pipe by way of a force-loaded locking device which can be unlocked axially by traction on the supply hose against the loading force. This arrangement on the one hand prevents undesired reversal and on the other hand enables reversal to be effected under pressure.