a stacking machine includes a pair of gripping jaws that are openable and closable to grip a leading edge of an article and move it to a stacking position . the jaws are moved between a gripping position and a release position by a fluid cylinder assembly and are automatically moved to an intermediate position when the jaws are moved to receive an article . air flow is used to straighten the trailing part of the article on the stack . the gripping jaws are moved between an article receiving position and an article discharge position by a pneumatic cylinder assembly that will accommodate variations in stack height .