Abstract: An apparatus for continuously varying the position of an article carrying platform in response to an inflowing stream of articles placed on the platform. The platform positioning apparatus finds use as part of a vertical stacking machine which stacks an inflowing stream of signatures on the platform. It has a position sensor for detecting the position of the platform and providing a platform position signal to a controller. A controller issues a translation signal to a translation motor responsive to the platform position signal. The translation motor causes the bidirectional translation of the platform responsive to the translation signal from the controller.

Abstract: A process control system for monitoring and controlling elements of a process. A control unit is electrically connected to a multi-conductor cable upon which are removably connected in series configuration a plurality of serially addressable control modules. The control modules are removably connected to elements of the controlled process to permit monitoring and control of the elements. The modules may be readily connected to or removed from the process elements and multi-conductor cable, to permit expansion or modification of the control system as needed for proper use in controlling process systems. The control modules operate independently from outside signals in monitoring the process elements, and respond to selected element status conditions by accessing communication with the central controller on a priority basis over other control modules in the system. The control unit includes a touch sensitive video screen for providing information to an receiving instructions from a user.