Abstract: A maintenance free, easy to install portable dock system has a molded shell constructed of a UV resistant, linear low density polyethylene. The dock shell includes a plurality of internal columnar supports strategically located to provide structural integrity as well as a desired adhesive surface area for the polyethylene. An "L" or "T" pier type or floating type dock can be formulated simply by coupling a desired number of dock shells together in a desired configuration via a full width self-aligning latching structure which does not require the hand and eye coordination generally required for known dock structures. The dock shell has support beams which run longitudinally over the entire length of the dock shell. Metal stringers are inserted into the outer most support beams to further enhance the structural integrity and increase the rigidity of the dock shell. Buoyancy for the dock shell is ensured with a polyurethane foam which is injected into the dock shell.

Abstract: A maintenance free, easy to install portable dock system has a rotational molded shell constructed of a UV resistant, linear low density polyethylene. The dock shell includes a plurality of internal columnar truss supports strategically located to provide structural integrity. An "L" or "T" pier type or floating type dock can be formulated simply by coupling a desired number of dock shells together in a desired configuration via a full width self-aligning latching structure which does not require the hand and eye coordination generally required for known dock structures. The dock shell has support beams which run longitudinally over the entire length of the dock shell. Metal stringers are inserted into the outer most support beams to further enhance the structural integrity and increase the rigidity of the dock shell. Buoyancy for the dock shell is ensured with a polyurethane foam which is injected into the dock shell.

Abstract: The invention is directed to apparatus for controlling the lateral tracking movement of a wide abrasive belt back and forth over back supporting rollers. The apparatus is employed in the grinding head of an abrasive grinding machine in which the endless abrasive belt is movably carried by at least two spaced rollers. The upper roller is rotatably mounted in a cradle that pivots within the grinding head about an axis perpendicular to the roller axis and passing through the roller midpoint. Pivotal swinging of the cradle about this axis, as effected by opposed pneumatic actuators, causes the abrasive belt to track back and forth over the rollers. The tracking movement is cyclically controlled by a photodetector that cooperates with a solenoid valve to alternately actuate the pneumatic actuators.

Abstract: The disclosure is directed to a self-centering feed apparatus for a dual head abrasive grinding machine. The grinding heads are mounted in opposed vertical relation, and workpieces are fed therebetween along a horizontal center line or plane. The self-centering feed apparatus comprises at least two sets of control arm mechanisms mounted above and below the center line. The control arm mechanisms of each set are mounted in side-by-side relation on a common pivot shaft, and are independently movable toward and away from the center line as the workpieces move through. Each mechanism includes a drive wheel for engaging the workpiece and driving it through the machine. Each control arm mechanism is urged toward the center line by a spring loaded pneumatic actuator that provides a constant gripping force, and which also generates a resistive force that increases as a function of deflection of a control arm mechanism from the center line.