Abstract: The subject invention is directed to a control system for a turboshaft engine utilized in a helicopter which includes means for providing minimum fuel flow to the engine when an overspeed condition is detected at a relatively low altitude (e.g., below 10,000 feet), and means for shutting off fuel flow to the engine, and thus shutting down the engine, when an overspeed, loss of load condition is detected at a relatively high altitude (e.g. above 10,000 feet). The overspeed, loss of load condition is detected along two different engine speed signal paths, including a derivative path and a non-derivative path.

Abstract: A control system is disclosed for optimizing the transient response of a gas turbine engine by controlling the variable positioning of compressor inlet guide vanes. The system employs a normal mode schedule which schedules relatively closed inlet guide vane settings at low compressor speeds and relatively open inlet guide vane settings at high compressor speeds. The system further employs an alternate mode schedule that schedules inlet guide vane settings that are more closed at low compressor speeds than those scheduled by the normal mode schedule. Control logic is provided for rapidly moving the inlet guide vanes from the more closed settings of the alternate mode schedule to settings which are more open than those which are schedule by the normal mode schedule, during an acceleration from low engine power levels. The control logic is further configured to command the inlet guide vanes back to the normal mode schedule as the acceleration nears completion.

Abstract: A control system is disclosed for optimizing the transient response of a gas turbine engine by controlling the variable positioning of compressor inlet guide vanes. The system employs a normal mode schedule which schedules relatively closed inlet guide vane settings at low compressor speeds and relatively open inlet guide vane settings at high compressor speeds. The system further employs an alternate mode schedule that schedules inlet guide vane settings that are more closed at low compressor speeds than those scheduled by the normal mode schedule. Control logic is provided for rapidly moving the inlet guide vanes from the more closed settings of the alternate mode schedule to settings which are more open than those which are schedule by the normal mode schedule, during an acceleration from low engine power levels. The control logic is further configured to command the inlet guide vanes back to the normal mode schedule as the acceleration nears completion.

Abstract: A control system is disclosed for optimizing the transient response of a gas turbine engine by controlling the variable positioning of compressor inlet guide vanes. The system employs a normal mode schedule which schedules relatively closed inlet guide vane settings at low compressor speeds and relatively open inlet guide vane settings at high compressor speeds. The system further employs an alternate mode schedule that schedules inlet guide vane settings that are more closed at low compressor speeds than those scheduled by the normal mode schedule. Control logic is provided for rapidly moving the inlet guide vanes from the more closed settings of the alternate mode schedule to settings which are more open than those which are schedule by the normal mode schedule, during an acceleration from low engine power levels. The control logic is further configured to command the inlet guide vanes back to the normal mode schedule as the acceleration nears completion.

Abstract: A control system is disclosed for optimizing the transient response of a gas turbine engine by controlling the variable positioning of compressor inlet guide vanes. The system employs a normal mode schedule which schedules relatively closed inlet guide vane settings at low compressor speeds and relatively open inlet guide vane settings at high compressor speeds. The system further employs an alternate mode schedule that schedules inlet guide vane settings that are more closed at low compressor speeds than those scheduled by the normal mode schedule. Control logic is provided for rapidly moving the inlet guide vanes from the more closed settings of the alternate mode schedule to settings which are more open than those which are schedule by the normal mode schedule, during an acceleration from low engine power levels. The control logic is further configured to command the inlet guide vanes back to the normal mode schedule as the acceleration nears completion.

Abstract: A retractor for performing surgery, for instance cardiac surgery on the coronary organs of a patient, which has a driving member to which the surgeon input is applied in the form of a mechanical force or torque, a thoracic structure engaging member which interfaces and retracts the patient's thoracic structure when surgeon input is applied to the movable driving member, and a surgeon input load-reducing and load-normalizing mechanism provided in at least one mechanical interface between retractor components where relative motion therebetween occurs. The load-reducing and load-normalizing mechanisms are preferably non-lubricated, thereby tending to ensure an inert and sterile environment during surgery. The retractor is comprised of a locking arrangement allowing a retractor spreader arm to be secured at any longitudinal position along the rack bar, independently of the pinion's position.

Abstract: A retractor for performing surgery, for instance cardiac surgery on the coronary organs of a patient, which has a driving member to which the surgeon input is applied in the form of a mechanical force or torque, a thoracic structure engaging member which interfaces and retracts the patient's thoracic structure when surgeon input is applied to the movable driving member, and a surgeon input load-reducing and load-normalizing mechanism provided in at least one mechanical interface between retractor components where relative motion therebetween occurs. The load-reducing and load-normalizing mechanisms are preferably non-lubricated, thereby tending to ensure an inert and sterile environment during surgery. The retractor is comprised of a locking arrangement allowing a retractor spreader arm to be secured at any longitudinal position along the rack bar, independently of the pinion's position.

Abstract: A surgical apparatus is described for performing cardiac surgery on the coronary organs of a patient. It has a contacting means capable of providing a mechanical load on at least a portion of said coronary organ, a positioning means which allows the setting of either or both the contacting means and coronary organ in a large number of positions or orientations within a surgical workspace. The apparatus also has a manipulation means serving as a single point control to position and orient the contacting means onto the coronary organ tissue. An adjustment means serves to bias the range of at least one motion degree of freedom of the surgical apparatus within a the limits of a restricted range that is less than the full range of motion of that degree of freedom of motion that would be otherwise achievable when the bias is not present or overridden.