The clamping pads of the gripper door and board carrier go over the edge of a sheet and you lift the handle, which causes the pads to clamp onto the sheet so it can be pulled or lifted. The pads are joined to the handle with bolts, allowing them to pivot towards each other.
The more pressure applied to the handle, the tighter the grip will be, so heavy sheets will be held securely. They can be used to lift a sheet vertically or pull one horizontally.
You need to keep the pressure constant to carry a sheet or door with the gripper carrier. When the pressure is loosened on the handle, even if just briefly, the clamps will release the sheet.
