tax and regulatory system for the programmed movement of the arbeitsgeraete of self-propelled machines, in particular frontladern

摘要

1,185,568. Electric correspondence control system. INTERNATIONAL HARVESTER CO. Sept. 18, 1968 [Sept. 18, 1967], No. 44335/68. Heading G1N. [Also in Division G3] A materials handling mechanism comprises a tractor loader frame 14 about which a boom 16 is pivoted by hydraulic actuator 20 and carries a bucket 18 pivoted about it by linkages 28, 30 driven by hydraulic actuator 24, each actuator producing a voltage signal of magnitude proportional to actuator extension across respective arms of a Wheatstone bridge 54. The out-of-balance signal controls an hydraulic motor system which moves the bucket to a predetermined position for each of a plurality of boom positions, simultaneously rebalancing the bridge. Manual selection of either of two operational positions of a control lever 22 shifts the spool of a control valve 36 so as to extend or retract a rod 44 forming part of the boom actuator, and simultaneously to apply a direct voltage from a battery 76 to a first diagonal of the bridge. Movement of the rod is coupled by a cable 46 to sliding contacts 48, 49, thus varying proportionally the resistance of a manually selected one of a pair of resistor banks 50, 52 so as to produce a first feedback voltage signal between conductors 56, 62 of the bridge. Similarly a resistance 65, varied by movement of actuator rod 68, provides a second feedback voltage proportional to bucket actuator extension. In either case an equivalent feedback signal may be produced by other means e.g. an hydraulic pressure varying as actuator extension. A given unbalance in voltage amplitude across the second bridge diagonal energizes a relay 84 which operates switch 90 thus energizing, from voltage source 96, one or other of two solenoids 98, 102 to control the retraction or extension of the bucket actuator 24 until the bridge is rebalanced. The values of the resistors in the banks 50, 52 are pre-set for a desired coordination of boom and bucket movement, bank 50 being used for boom raising and 52 for lowering, calibration being effected by use of galvanometer 80 and switch 82. In operation the programme may be varied manually by knob 64 varying bank 50 or 52.