Abstract: A hand-held pointer control and input device has a case configured to be gripped by a right or left hand, with a curved back surface which fits against a palm of a hand gripping the device, a saddle-shaped surface configured to support and position a thumb of the gripping hand for operation of a cursor control device which protrudes from the top surface, and a curved button mounting surface positioned generally opposite the curved back surface and with at least one control button incorporated therein. The device enables control of a display cursor and input of control commands which correspond to a position of a cursor with a single hand and without contacting the device with a reference surface. A modular pointing stick and circuit board assembly is also provided.

Abstract: A system and method are provided for the automatic regulation of a balancing pressure to be applied to a rotor of a rotary screw compressor. The system includes a microprocessor which computes a balancing pressure to be applied to the rotor in response to an input of various compressor operating parameters such as suction pressure, discharge pressure, and percent capcity.