Geraet fuer eigenen pneumatischen Vortrieb

摘要

1,044,201. Pull-through rods. POSTMASTER GENERAL. Oct. 9, 1963 [Oct.10,. 1962], No. 38454/62. Heading F2N. An apparatus for self-propulsion along a duct has an elongated pneumatically-operable telescopic body supported at the leading and trailing ends thereof by inflatable bag grips 2, 21, a pneumatic pressure distributer valve 31, Fig. 3 (not shown), movable between first and second operative positions for distributing pneumatic pressure alternately to extend the body with the bag grip 21 inflated to a predetermined pressure sufficient to firmly grip the duct wall and with the bag grip 2 sufficiently deflated to permit sliding movement thereof along the duct, and to contract the body with the bag grip 2 inflated to a predetermined pressure sufficient to firmly grip the duct wall and with the bag grip 21 sufficiently deflated to permit sliding movement thereof along the duct, and resilient means responsive to the extension and contraction of the body for effecting the said movement of the distributer valve between the first and second operative positions thereof. The body A comprises a cylindrical member 3 having a piston 4 slidable therein and respectively having the bag grips 2, 21 connected thereto. There are control valves 20, 201, respectively operable by and during extension of the body to permit deflation of the bag grip 2 and operable by and during contraction of the body to permit deflation of the bag grip 21. In both bags, spring-loaded air escape valves 25, 251, which function also as safety valves, open at a predetermined pressure if the pressure inside the bag grips should rise too much. The bag grips, of polyvinyl chloride or oil-resistant synthetic rubber, have longitudinal grooves to facilitate escape of air trapped between the bag grips when the bag grips are drawn towards each other. The device is used to negotiate a duct drawing a length of rope or flexible wire along with it and by means of which a cable can subsequently be laid in the duet. Two devices may travel towards each other from opposite ends of a duct the leading end of one device having a male coupling member and the other device being provided with a coupling device comprising spring-loaded jaws.