Control valve means

US5370037A · kind A · utility

Inventors

• Joachim Bauer · Hamburg, DE
• Klaus Albrecht · Mainz, DE
• Rolf Krahmer · Ahrensburg, DE

Key dates

• Filing date: Nov 16, 1993
• Grant date: Dec 6, 1994
• Expiry date: Nov 16, 2013

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B25C1/042
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

The present invention relates to a valve control apparatus for operating a working piston, comprising a main valve spool including a smaller piston face subjected to compressed air from a reservoir and a larger piston face facing a main control space, further comprising an auxiliary valve spool having a first effective area which can be connected by a trigger valve to atmosphere or to a compressed air reservoir to displace the main control spool into an open position, and having a second effective area which is connected to a piston stroke chamber for displacing the main valve spool into a closed position, wherein the auxiliary valve spool is returned when the pressure acting on its second effective area falls below a predetermined value, wherein this effective area is connected to a shift valve which communicates with atmosphere when the trigger is not actuated and which is closed when being actuated and wherein the trigger is provided to move a first length of travel and a second length of travel to actuate the shift valve, while the trigger valve is maintained to be activated, wherein the shift valve has a tappet which closes an outlet opening connecting the second effective are…