Method for lifting and conveying bale rubber and device for the same with grip safety mechanism

A method for lifting and conveying bale rubber, comprising:

• supporting a plurality of claws inside a claw housing case of a gripping device including a claws-entering-and-exiting surface on an undersurface side that comes into contact with an upper surface of bale rubber that is an object of the lifting, opening portions through which a plurality of the claws appear and disappear being formed on the claws-entering-and-exiting surface, a distal end of each of the plurality of claws being made acute by gradually reducing the diameter from a base end side to a distal end side and a central axis line of each of the plurality of claws being bent so as to form an arc shape about an axis line of a rotational drive, the plurality of claws being supported so as to be capable of being rotationally driven in a direction extending along the central axis line having the arc shape about the axis line of the rotational drive disposed horizontally;
• providing a claw drive mechanism on a frame of the gripping device for piercing the plurality of claws into the upper surface of the bale rubber in a gripping manner through the opening portions of the claws-entering-and-exiting surface while drawing a trajectory with the arcuate shape;
• gripping the bale rubber by protruding each of the plurality of claws through a corresponding one of openings provided in the claws-entering-and-exiting surface and by piercing the plurality of claws into the bale rubber from an upper surface of the bale rubber so as to draw a trajectory having the arc shape, while the claws-entering-and-exiting surface is abutted against the bale rubber that is the object of the lifting;
• and
• transferring the bale rubber that has been gripped with the claws to a target position with a conveying mechanism that moves laterally, after lifting the bale rubber together with the claw housing case with a lift mechanism including a hydraulically driven lift cylinder;
• wherein
• an operation of gripping the bale rubber with the claws is performed by providing a detection tip of a contact sensor disposed on the claws-entering-and-exiting surface of the claw housing case and detecting contact made with the bale rubber on the claws-entering-and-exiting surface of the claw housing case, disabling a grip safety mechanism in the operation circuit of the drive mechanism gripping the bale rubber with a contact signal generated by the contact sensor upon contact with the bale rubber, the grip safety mechanism making the claws non-operative by opening the operation circuit when the contact sensor in not on contact with the bale rubber, and enabling driving of the claws performed with the drive mechanism upon operation of a gripping operation element;
• and wherein
• the grip safety mechanism cancels the non-operative state by a contact signal generated by the contact sensor when in contact with the bale rubber and enables an operation of gripping the bale rubber with the claws by closing the operation circuit of the claw drive mechanism upon operation of the gripping operation element.