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Valve and cylinder-actuated lock controlled thereby

  • US 4,169,616 A
  • Filed: 09/26/1977
  • Issued: 10/02/1979
  • Est. Priority Date: 09/26/1977
  • Status: Expired due to Term
First Claim
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1. A valve comprising:

  • a valve body having a spool bore, an inlet passage that opens into the spool bore, first and second outlets, first and second valve chambers connected with the first and second outlets, respectively, first and second transfer passages extended from the spool bore to the first and second valve chambers, respectively, first and second return passages extended from the first and second valve chambers, respectively, to the spool bore and opening into the spool bore beyond the transfer passages;

    a spool in the spool bore generally between the ends of the two return passages and being capable of shifting therein between first and second positions, the spool being configured to direct pressurized fluid from the inlet passage to the first transfer passage when in the first position and to direct pressurized fluid from the inlet passage to the second transfer passage when in the second position, the spool further being configured such that its ends are continually exposed to the ends of the return passages such that a pressurized fluid in either return passage will exert an axially directed force on the spool, with pressurized fluid supplied through the first return passage urging the spool to its second position and pressurized fluid applied through the second return passage urging the spool to its first position; and

    a blocking element in each valve chamber for blocking the return passage that opens into that valve chamber when pressurized fluid flows through the transfer passage and into the valve chamber and for alternatively blocking the transfer passage that opens into the valve chamber after a back pressure develops in fluid at the outlet passage for the valve chamber and pressurized fluid is no longer supplied to the inlet passage, whereby fluid under back pressure is diverted to the return passage for the valve chamber and exerts an axial force on the spool, with the force being directed such that it causes the spool to change position, so that successive applications of pressurized fluid to the inlet passage are alternatively directed to the first and second outlet passages.

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