Patent ID: 6016056
Filing Date: 2000-01-18
Classification: B29C,G01D,G01P

Abstract:
A device for an injection molding machine, the device detecting a displacement and a speed of a movable injection-molding part moved by an actuator (31) of the injection molding machine; the device comprising:(a) an encoder (3), coupled to the injection-molding part and generating, upon a motion of the injection-molding part, two pulse waves (A,B) each having a common pulse frequency, the two pulse waves being out of phase by approximately a quarter cycle;(b) a pulse treatment section (14,15), coupled to the encoder, producing subdivided trigger pulses (Gf, Gr) having a trigger pulse frequency being a multiple of the common pulse frequency;(c) a basic clock generator producing basic clock pulses;(d) a first counter (19,20), coupled to the pulse treatment section, counting the trigger pulses from the pulse treatment section;(e) a latch (17,18), coupled to the pulse treatment section, latching the trigger pulses from the pulse treatment section;(f) a second counter (21, 22), coupled to the latch and the basic clock generator, counting the basic clock pulses during a latched interval between the trigger pulses;(g) a controller coupled to the actuator and the encoder, the controller includinga speed calculator dividing a clock count from the second counter by the latched interval and comprising means to obtain a speed of the injection-molding part from a quotient thereof; anda displacement calculator comprising means to obtain a displacement of the injection-molding part from a trigger count of trigger pulses input to the displacement calculator from the first counter.