SAS uses heavy-duty linear slides instead of typical aluminum profile frames to make their bag gripper more robust and accurate.
With years of experience in the declining automotive marketplace, SAS Automation in Xenia, Ohio, recently ventured into the consumer-products palletizing market. More specifically, SAS surveyed palletizing system integrators and discovered a need for durable bag grippers. “No bag grippers on the market delivered the durability required for palletizing, and downtime for repair or replacement can be costly when one must get goods onto pallets and out the door,” reports SAS Automation's general manager, Robert Dalton.
To address the need, SAS set out to create an end-of-arm tool for handling the largest bag size typically found in Europe — 50 kg. The result (launched in October 2009) is the ABG-50, a 78-kg bag gripper for palletizing plastic, woven cloth, or paper bags. The gripper eliminates the need for custom tooling with a width adjustment system: In less than 30 seconds, an operator can change the tool's bag width from between 191 and 533 mm using a handwheel-driven leadscrew and two shaft-lock mechanisms. Otherwise, an optional servodrive can adjust the width on the fly to accommodate mixed loads. Slip-sheet and pallet hook options further increase functionality.
Central to the gripper's durability is its rails: SAS technical sales specialist John Prater says, “Other so-called adjustable grippers use aluminum profile frames that wear quickly and do not adjust easily. We have years of experience using linear slides in products such as our shuttle tables and punch press degaters — so we approached our longtime supplier Rollon Corp., Sparta, N.J., to help us develop an alternative.” Rollon's application engineers recommended the Compact Rail for the bag gripper because its slides are accurate and durable, and include wipers and grease ports that facilitate maintenance — an important factor in dusty and dirty packaging environments, particularly where grains, chemicals, minerals, or concrete cement are packaged.
More specifically, the ABG-50 utilizes the Compact Rail Series 43, which provides a 43-mm mating mounting surface dimension across the backside of a cold-drawn steel rail. This linear guide is available in lengths up to four meters long, and the rails are completely joinable for even longer guidance. SAS Automation general manager Robert Dalton adds, “The linear slides also enabled us to divide the bag gripper, so each side operates independently in actuation. This in turn eliminates the mechanical linkage that would require adjustment each time the bag size was changed.”