Abstract: The present invention is directed to a hydro-mechanical or electro-hydro-mechanical control system utilized for positioning a mechanical device. The control system incorporates an improved closed-center control valve for selectively controlling the differential pressure applied to the input ports of a power output transducer and the differential flow therebetween in response to a mechanically applied rotational input. The power output transducer is then utilized to position a mechanical device. The control system is a closed loop circuit adapted to supply hydraulic fluid at a desired supply pressure to the control valve. The improved closed-center control valve is a modified rotary valve wherein parasitic leakage slots are formed for providing a leakage flow pathway through the control valve between the input ports of the power output transducer.

Abstract: A reaction type control valve, primarily intended for controlling a power assisted steering system, comprising a hydraulic interface having variable effective reaction areas, the extent of which is determined by selected functions of values of torque applied thereto. Differential hydraulic fluid pressure is generated by the valve, which differential hydraulic fluid pressure is proportional to the applied torque and inversely proportional to any particular effective reaction area. Hydraulic fluid is induced to flow through a hydraulic interface between first and second valve members wherein primary and secondary sets of input and return orifices are selectively utilized to define the effective reaction areas as a function of the input torque. The primary and secondary sets of input and return orifices are located at selected radii.

Abstract: The present invention is directed to a hydro-mechanical or electro-hydro-mechanical control system utilized for positioning a mechanical device. The control system incorporates a control valve for selectively controlling the flow of hydraulic fluid to input ports of a power output transducer. The power output transducer is then utilized to position a mechanical device. The control system is a closed loop circuit adapted to supply hydraulic fluid at a desired supply pressure to the control valve. The supply pressure is varied in relation to the absolute value of the pressure differential or load pressure exerted across the input ports of the power output transducer. A pressure regulating apparatus is provided for selectively regulating the supply pressure to a value that is nominally equal to the absolute value of the load pressure summed with a preselected supplemental pressure value across the regulating apparatus.

Abstract: An endoscopic suture tool is provided to minimize extra-corporeal exposure of the suture to bacteria and to minimize the possibility of suture entanglement with external trocars and other instruments. The suture tool has a holder with a protrubing hub for accepting a standard suture reel and an orifice through which the suture feeds into and through the lumen of an extension member releasably carried by the holder. Adjacent the distal end of the extension member, a slot is located in the extension member for captively and releasably holding the free end of the suture.

Abstract: A surgical fastener system for fixing a mesh prosthesis to body tissue for the laparoscopic repair of inguinal herniation or for fixing body tissue to body tissue. A unidirectional dart fastener is utilized where the dart fastener is composed of a shaft member and an anchor member extending angularly from the tip of the shaft. The anchor member is resiliently collapsable radially to the shaft and biased in an open position which permits the dart to be captively held unidirectionally in the body fascia. A dart fixation tool carries the dart fastener in a cartridge which has a series of cylindrical chambers spaced radially adjacent to the periphery of the cartridge and the dart is ejected into the body tissue by a setting rod which is responsive to an external force to thrust the rod through the chamber. The setting rod is thereafter retracted from the chamber and the cartridge is rotated by the surgeon to bring another succeeding chamber into alignment with the setting rod.

Abstract: The invention relates to a instrument for laparoscopic surgery which permits the operating surgeon to irrigate or suction the operative area while performing electrocautery or laser hemostasis and dissection of body tissue with the same instrument.The invention also relates to a laparoscopic tool for evacuating free stones or blood clots from the operating area which are to large to be suctioned from the body cavity or to remove gallstones from a gallbladder which has been distended by stones and cannot be retrieved through an umbillical sheath.

Abstract: A tachometer particularly adapted for operation as a rotational velocity feedback transducer is provided. First and second proximity detectors are used to monitor orthogonal positions of an irregular surface portion of a rotating shaft and provide x and y signals that are substantially in quadrature. The x and y signals are differentiated with respect to time to provide differential signals that are representative of dx/dt and dy/dt, respectively. Signals representative of products x dy/dt and y dx/dt are generated from the x signal and the differential signal dy/dt, and the y signal and the differential signal dx/dt, respectively. A signal representative of algebraic sum x dy/dt--y dx/dt is generated from the signals representative of products x dy/dt and y dx/dt. A signal representative of quotient of (x dy/dt-y dx/dt) divided by the displacement r.sup.

Abstract: An improved power steering system in which the ratio of output force to input torque is variable. The power steering system includes an input shaft as well as an inner valve member and an outer valve member which are able to generate hydraulic fluid pressure in response to the input torque. A rack assembly is provided for generating the output force in response to the hydraulic fluid pressure generated in response to the input torque. The improved power steering system further includes a pinion shaft which mechanically communicates with the rack assembly and provides a reference position for the improved power steering system. A torsion bar compliantly couples the inner valve member to the pinion shaft, a twist angle of the torsion bar serving to provide a position error signal to the improved power steering system. Finally, a torsion bar extension compliantly couples the torsion bar to the input shaft.

Abstract: An improved power steering system for motor vehicles of the type used for steering dirigible wheels is disclosed. In particular, the improved system is a rotary valve equipped power steering system in which the steering wheel is coupled to the rotary control valve via a coupling device having a rotational stiffness characteristic that is less than the rotational stiffness characteristic associated with the rotary valve itself.

Abstract: A tachometer particularly adapted for operation as a rotational velocity feedback transducer is provided. First and second proximity detectors are used to monitor orthogonal positions of an irregular surface portion of a rotating shaft and provide x and y signals that are substantially in quadrature. The x and y signals are differentiated with respect to time to provide differential signals that are representative of dx/dt and dy/dt, respectively. Signals representative of products x dy/dt and y dx/dt are generated from the x signal and the differential signal dy/dt, and the y signal and the differential signal dx/dt, respectively. A signal representative of algebraic sum x dy/dt-y dx/dt is generated from the signals representative of products x dy/dt and y dx/dt. A signal representative of quotient of (x dy/dt-y dx/dt) divided by the square of the displacement r.sup.

Abstract: In an X-Y addressable workpiece positioner the workpiece to be positioned, such as a semiconductive wafer to be aligned with a mask image, is coupled to move with a work stage moveable in X and Y direction and having a two-dimensional array of positioning indicia affixed thereto for movement therewith. An enlarged image of a portion of the positioning array is projected onto a relatively stationary sensor stage to derive an output determinative of the X and Y coordinates of the positioning array relative to the position of the sensor. The sensed X and Y coordinates of the positioning array are compared with the X and Y coordinates of a reference positioning address to derive an error output. The work stage is moved in response to the error output for causing the workpiece to be positioned to the reference address.

Abstract: A steering assembly for multiplying steering torque and motion applied from a steering wheel of a vehicle by fixed and selectively varying ratios, respectively. The applied steering torque and motion are coupled via an input shaft to a sun gear of a planetary gear set. Supplementary torque and steering motion are generated by a servo motor which is coupled to a ring gear of the planetary gear set via an irreversible differential planetary gear set. Rotational motion of the input shaft is determined and rotational motion of the servo motor is controlled as a selected function of the rotational motion of the input shaft. Actual rotational motion of the servo motor is measured and additional rotational motion of the servo motor is terminated if the actual rotational motion of the servo motor does not substantially match the selected rotational motion. A set of planetary gears mounted in a planetary carrier receives combined output torque and rotational motion from both the sun and ring gears.

Abstract: A building panel module incorporating spaced inner and outer wall surfaces of metallic sheet construction to provide both longitudinal and transverse load carrying capabilities. The module includes interior baffles that are positioned between the inner and outer wall surfaces and that overlap each other to prevent direct pathways between the inner and outer wall surfaces so that ballistic projectiles that penetrate one wall surface must also pass through the baffles before impacting the other wall surfaces, thereby reducing their energy level to such an extent that they do not penetrate the innermost wall surface. Additionally, the module incorporates one or more integral I-beam elements that provide substantial longitudinal load carrying capacity, as well as providing resistance to transversely applied loads, such as wind loads, blast loads, and the like.

Abstract: A valve for controlling a double-acting utilization device includes inner and outer valve members where the outer valve member has pressure slots with first and second lateral edges, respectively, and the inner valve member includes first and second lands with third and fourth lateral edges, respectively. The first and third lateral edges form input orifices and second and fourth lateral edges form return orifices. The effective radial positions of the input and return orifices are chosen to generate reaction torque within the valve itself. Drive torque and position are applied to the outer valve member and feedback torque and position are communicated to the inner valve member via a torsion bar which is coupled to an output member of the double-acting utilization device.

Abstract: An improved solid state commutated linear motor with an ironless multiphase armature is disclosed which has a magnetic field array having periodic alternating polarity, an ironless multiphase armature, and a solid state commutating system for driving a moving element and positioning it with respect to a reference element. In one embodiment, the magnetic field array is elongated and fixedly located with respect to the reference element, and the ironless multiphase armature is fixedly located with respect to the moving element. In a second embodiment, the ironless multiphase armature is elongated and fixedly located with respect to the reference element, and the magnetic field array is fixedly located with respect to the moving element. The magnetic field array is generated by an array of spaced alternate north and south poled magnets having an inter-pole distance L.

Abstract: An improved step and repeat alignment and exposure system for printing an image of a recticle onto a semiconductive wafer. A unit magnification catadioptric lens projects the recticle image onto the semiconductive wafer, and includes prisms to separate the image plane of the lens from the object plane. The semiconductive wafer is supported on stage means, which stage means provide motion in the X,Y directrions. Viewing port means supplement the unit magnification catadioptric lens to provide a direct view of a portion of the semiconductive wafer which portion has been illuminated by the projected recticle image. A beam splitter is formed on a face of one of the prisms of the unit magnification catadioptric lens and is supplemented by an additional prism which provides optical path compatibility.

Abstract: An improved gas bearing X-Y-.theta. stage assembly is disclosed which has a base, a stage element with three retroreflectors fixedly mounted thereto, and a control system for controlling the movement of the stage element. The control system is made up of three interferometer measuring systems for measuring parameters associated with changes in position of the three retroreflectors as the stage element moves. Also, the control system includes a transport system for moving the three interferometers to maintain optical coupling between the interferometers and retroreflectors. In addition, the control system includes control circuitry for causing the stage element to move to a preselected X-Y-.theta. position in response to signals from the interferometer measuring systems.

Abstract: A building panel element formed from sheet steel and having a rectangular wall member and inwardly directed panels that extend along longitudinal edges of the rectangular member. A plurality of panel elements are positioned for end-to-end assembly with a plurality of corresponding panel elements positioned opposite thereto and spaced therefrom in staggered relationship to define a building module having spaced parallel faces and having one or more inner compartments defined by the inwardly directed panels. The inner compartments can be filled with insulating materials, concrete, rock, armor plate, and the like, as desired, to provide required module properties. Modules formed from such building panel elements can be prefabricated in a factory and carried to a building site for assembly either as individual elements, as prefabricated wall modules, or as prefabricated room modules.

Abstract: Statically pressurized gas bearings employ improved bearing pockets, each including one or more slots arranged in a double cross, star or other configuration, and supplemental gas exhaust slots, as well as stepped annular land flow restrictors, to optimize bearing stability and operational bandwidth.

Abstract: A dark field alignment system is provided wherein a bifurcated light source, including a secondary channel having spot sources of light located in a plane conjugate to the object plane of a reduction lens and directed through a peripheral ring of a plane conjugate to the apertgure plane of the reduction lens, illuminates the object plane of the reduction lens. Reflected and defracted light from an alignment mark of a semiconductive wafer in the image plane of the reduction lens is captured by a mirror located near the aperture plane of the reduction lens. This light is refocused to another plane conjugate to the object plane of the reduction lens and imaged onto detector arrays to provide alignment information.