Abstract: A variable force push button is used as an input device for a control system. Specifically, a bi-directional storage device produces a command that is applied to an element to be controlled. A signal is generated having a characteristic representative of the force applied to the push button. A representation of the characteristic is integrated by the storage device. In addition to changing the characteristic by varying the force applied to the push button, the user can change the direction of the integration, thereby increasing and decreasing the value of the command. The push button comprises a pressure sensitive element sandwiched between electrically conductive contacts one of which is actuated by the user. The pressure sensitive element is constructed of conductive particles in an elastomeric matrix. Preferably, electrically conductive micro-agglomerates of unbound finely divided electro-conductive carbon particles having a maximum dimension of between about 0.

Abstract: A hydraulic clutch device which uses a gear pump design as its main element which, in effect, has nowhere to pump.Its center gear is driven by the input shaft while its housing unit can also rotate and comprises the output shaft.The center gear meshes with two outer gears and also slides axially so that the amount of its teeth that mesh with the outside gears can be varied. The axial movement of the center gear being achieved with hydraulic pressures and vacuums supplied from within the clutch itself and controlled by a central control slide valve which runs through the center of the input shaft and is controlled by a manually operated lever attached to the supporting framework and coupled to the slide valve with a throwout bearing device.By moving the center gear over so that it fully meshes with the outer gears the clutch is engaged, and by moving the center gear over the other way so that only a small portion of it meshes with the outside gears the clutch is disengaged.

Abstract: The present invention relates to a hand truck apparatus which is designed for transporting large cylindrical objects such as compressed gas storage tanks, for example. The hand truck apparatus includes a main frame assembly supported by a pair of spaced apart ground engaging wheels. A load supporting mechanism is movably mounted on the main frame assembly and includes a securing strap adapted to surround the object and urge the object into secure engagement with the load supporting mechanism. A hydraulic jack unit is provided for moving the load supporting mechanism and the object between a lower position and a selected upper position.