Metal which bends during the cut can bind the blade causing the operator to lose control of his saw, and heavy items can drop on the operator's feet when they fall free.
Still wearing her fluorescent jacket, she knelt down at least 15 meters in front of the bulldozer, and began waving her arms and shouting, just as activists had successfully done dozens of times that day.... Her head and upper torso were above the bulldozer's blade, and the bulldozer operator and co-operator could clearly see her.
Operators can move the robot between the blades while operating the camera using software they developed as part of the project.
During the whole of this operation, the operator must carefully control the position of the blade, compensating the tendency on the part of the nose of the tractor to go up (depositing) or to go down (excavating) by a slight correction in the opposite direction from the position of the blade.
It began early on July 16, when Pat Prouty, 73, stepped in front of a bulldozer's big metal blade and told the operator, "You're either going to go through me or over me, because I'm not moving". By that afternoon, work on a new underground pipeline that would carry millions of gallons of gasoline and aviation fuel past her South Whittier home had been halted.
In earthworks the preliminary operations are carried out thus: the tractor is started in first gear; the operator lowers the blade a few centimeters; under the action of the weight of the tractor the blade enters the ground and keeps pushing the material which piles up in front until it is full.
On the next movement forward the operator lowers the blade, puts it under the roots and pushes the stump, lifting the blade a little to take away the whole thing and to complete the uprooting.
The operator lets the blade rest on the ground and makes the machine advance while swinging round on one track.
At the end of each trip the operator raises the blade to make a shoulder across the width of the line of discharge.
By lowering the blade to the maximum, the operator digs and pushes the earth down the slope, thus making a platform which is partly cutting and partly embankment.
