Patent ID: 6370970
Filing Date: 2002-04-16
Classification: B66C,G01L

Abstract:
A cargo handling machine utilizing a force control method, the machine comprising:an elevation mechanism to raise and lower a cargo; a drive source for driving the elevation mechanism to raise and lower a cargo; an operating section coupled to the elevation mechanism and having a force sensor arranged to transmit a signal indicative of a vertical force applied to the operating section by a user; a detector coupled to the elevation mechanism to transmit a signal indicative of the vertical direction of movement of the elevation mechanism; and a control section having an electropneumatic proportional valve for controlling the drive source, the control section configured to operate the cargo handling machine in a first mode wherein the control section causes the drive source to generate a hoisting force that is amplified in accordance with the signal from the force sensor, and a second mode wherein the hoisting force is reduced at an attenuated time rate of change in response to a decrease in the signal from the force sensor and a signal from the detector indicating vertically downward movement of the elevation mechanism.