Patent Number: 6,480,773

Title: Automatic boom soft setdown mechanism

Abstract: A shovel including a dipper for gathering material from a bank. The shovel further includes a hoist motor operating control for operating a hoist motor, a speed sensor for monitoring the hoist motor speed, a torque sensor for monitoring the hoist motor torque, and a mechanism communicating with a crowd motor control, the torque sensor and the speed sensor for moving a dipper handle toward a boom when the hoist motor speed is below a low-speed value while under high torque, and for permitting movement of the dipper away from the boom when the hoist motor speed is above the low-speed value or not under high torque. The shovel further includes a linear resolver mounted on the platform, a rod having one end pivotally attached to the boom and another end attached to the linear resolver, movement of the rod causing a change in position of the linear resolver, a position mechanism for determining the position of the linear resolver, and a PLC communicating with the position mechanism and the crowd motor control mechanism for moving the dipper handle toward the boom in response to the position mechanism indicating the linear resolver has changed its position from a set point. The linear resolver includes a magnet slidably mounted on a base attached to the platform.

Inventors: Hilgart; Randall D. (Milwaukee, WI)

Assignee: Harnischfeger Industries, Inc.

International Classification: E02F 9/20 (20060101); E02F 3/43 (20060101); E02F 3/42 (20060101); E02F 003/00 ()

Expiration Date: 11/12/2019