Apparatus for adjusting starting positions of high speed injection

Claim 1

Apparatus for adjusting a starting position of high speed injection in a die cast machine, comprising: a position detector for detecting a stroke position of an injection plunger; a computer including means for calculating a first position of said injection plunger at which an instruction signal for starting a high speed injection is generated, and a second position of said injection plunger at which said injection plunger actually reaches a desired speed; data input means for presetting into said computer a predicted time interval (t D ) between an instant at which said instruction signal for starting a high speed injection is generated and an instant at which the plunger speed actually changes to said high speed, a predicted low injection speed (V L ) and a desired position (l START ) of the plunger at which the plunger speed actually changes to said high speed, said calculating means, based upon said preset data, determining said first position (l OUT ) corresponding to an initial state of the injection plunger stroke operation in accordance with the following first equation: l.sub.OUT =l.sub.START -(V.sub.L ·t.sub.D) and, then determining said first position (l' OUT ) corresponding to at least one successive stroke operation of the injection plunger in accordance with the following second equation: l'.sub.OUT =l.sub.START -(l.sub.H -l.sub.OUT) where l H represents said second position calculated at at least one successive stroke operation of the injection plunger; and an output circuit means responsive to an output of said computer for issuing said instruction signal for starting high speed injection of said injection plunger when said detected position of the injection plunger coincides with said first position during at least one stroke operation of the injection plunger.