Patent ID: 7651314

Claim:
A material stacker, comprising: a frame; a first plurality of stacking arms arranged along the frame; a second plurality of stacking arms arranged along the frame; one or more first electrically-controlled horizontal positioners configured to position the first plurality of stacking arms in a horizontal relationship with respect to the frame; one or more second electrically-controlled horizontal positioners configured to position the second plurality of stacking arms in a horizontal relationship with respect to the frame; one or more third electrically-controlled vertical positioners configured to position one or more of the first or second plurality of stacking arms in a desired vertical relationship with respect to the frame, wherein the electronic control system is configured to operate the one or more third electrically-controlled vertical positioners to control the vertical movement and positioning of the plurality of stacking arms based on the position of the stacking arms; and an electronic control system configured to control the operation of the one or more first electrically-controlled horizontal positioners independently of the one or more second electrically-controlled horizontal positioners based on a position of the corresponding stacking arms.