Hydraulic control means for pipe thrust-jacking apparatus

US4558629A · kind A · utility

Assignee

• Gewerkschaft Eisenhutte Westfalia GmbH · DE

Inventors

• Eberhart Unger · Grafenau, DE
• Herbert Heitkamp · Werne, DE

Key dates

• Filing date: Dec 9, 1983
• Grant date: Dec 17, 1985
• Expiry date: Dec 9, 2003

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F15B2211/782
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

Pipe thrust-jacking apparatus includes a pressure ring 5 which is advanceable by a plurality of hydraulic rams 3. The rams are controlled by hydraulic control means having a plurality of hydraulic control valves 19. Each control valve is associated with a respective hydraulic ram, and is connected to a first input line and to a second input line. Each of the first input lines is connected to a respective hydraulic fluid feed line 9, and each of the second input lines 17 is connected to a common hydraulic fluid supply line 11 and to an auxiliary pump P2. The common supply line is connected to all of the feed lines. Means 12,15 are provided for selectively connecting each of the hydraulic control valves to its first input line and/or its second input line.