| 摘要 |
932,069. Machine tool details. VECTRON ELECTRO PHYSICS Ltd. Jan. 24, 1962 [Jan. 27, 1961], No. 3309/61. Class 83 (3). [Also in Group XXIII] A system for controlling the distance moved by a tool in a turning, grinding, milling or drilling machine comprises a tool feed mechanism, a counting device coupled with the tool and with the feed mechanism, a sensing device normally positioned in the path of the tool having a face set at a known distance from the work, the sensing device being coupled to the counting device and serving on engagement with the tool to initiate counting, and the feedmechanism being adapted to stop the tool after a predetermined count. A workpiece 1 is held in a lathe and the tool slide 5 is moved by a feed mechanism FM. A metal strip 15 fixed to slide 5 rotates a roller 17 secured to a glass or other transparent disc 21 so that as slide 5 moves, a light 23 shines through apertures in disc 21 to supply pulses of light to a photosensitive device 24. A piezo-electric crystal 7 is mounted in a pivotable holder 8, the face 11 of the crystal being set at a known distance from workpiece 1. In operation, crystal 7 is oscillated by a circuit OSC, preferably at a resonance frequency and is connected to an amplifier circuit AMP1. The output from AMP1 is fed to a gate G coupled to a counting circuit CC, and the gate is also connected to device 24. When tool 4 contacts surface 11 a signal from amplifier AMP1 opens gate G and allows the pulses from device 24 to be fed to the counting circuit CC to initiate a count. A solenoid circuit SOC energizes a solenoid 12 to pivot crystal 7 away from the tool and after tool 4 has moved the required distance a signal is fed to mechanism FM to stop or retract the tool. A further piezo-electric crystal 26 mounted on slide 5 may be provided and is connected to an amplifier AMP2 which is coupled to a bistable multi-vibrator BMV which in turn is coupled to feed mechanism FM. Amplifier AMP2 detects surges in the output from crystal 26 when the tool engages the work and feeds a signal to BMV which in turn feeds a signal to mechanism FM to slow down the feed. |
