Abstract: A proximity sensor includes a bifurcated optic fiber bundle with a face and a projection lens for projecting an image on a target and a feedback control loop for maintaining said face at a preselected distance from the target for tracking. An oscillating device is provided which is disposed in the light path with fixed excursion between the face and the target and which generates an AC component in said sensor signal that is proportional to the deviation of the actual distance from the preselected distance, whereby the error signal is kept near zero.

Abstract: A method of determining the displacement of a fiber optic sensor from a target in which a first lens is spaced from the target at a first distance an a second lens is spaced from said target at a second distance which provides the greatest intensity response at said first distance and thereafter spacing said first lens from said second lens to provide symmetrical slope values of response.

Abstract: In the present system, the thickness of an object with two surfaces is determined by forming two geometric images on the surfaces in a superimposed relationship. The images are viewed by two video cameras and their relative positions with respect to two corresponding references are determined. These relative positions are used to measure the thickness of the object.

Abstract: An optical proximity detector including a set of transmitter fibers for directing light to a target and two sets of receiver fibers. One set of receiver fibers is combined with the transmitter fibers to from a central portion which is flanked by the second set of receiver fibers. Two light sensors and a signal processing circuit are also included to generate one output signal which is linear with respect to the distance to the target and is independent of the target reflectance. The detector is especially suited for monitoring targets having widths less than the diameter of the bundle, such as a turbine blade.

Abstract: A fiber optic proximity detector for use in sensing the relative position of an object or change thereof wherein the light is reflected by the target surface and returned along the transmitting fibers and utilized along with the reflected light returned along the receiving fibers so as to effect automatic surface reflectivity compensation with the detector being coupled to an optical extender to increase the working distance of the probe from the target.

Abstract: A vibration absorber unit or units are mounted on the exterior housing of a hydraulic drive system of the type that is powered from a pressure wave generated, e.g., by a Stirling engine. The hydraulic drive system employs a piston which is hydraulically driven to oscillate in a direction perpendicular to the axis of the hydraulic drive system. The vibration absorbers each include a spring or other resilient member having one side affixed to the housing and another side to which an absorber mass is affixed. In a preferred embodiment, a pair of vibration absorbers is employed, each absorber being formed of a pair of leaf spring assemblies, between which the absorber mass is suspended.

Abstract: A proximity sensor is disclosed having two bifurcate fiber optical bundles arranged in series. Light is directed at a target by the bundles and the reflected light from the target is transmitted to two different sensors. The output of the sensors is used to derive a differential control signal for tracking a target. One of the sensors picks up reflected light from the fibers which also transmit light to the target while the second sensor detects light from receiver fibers disposed around said transmitter fibers.

Abstract: A device for counting objects in a stacked relationship which includes a bifurcated optical cable, a light source for directing light through the bundle at the stack and a sensor for generating a signal proportional to the light reflected by the stack. The signal is digitized and fed to a digital counter. Various displays connected to the counter indicate the count results.

Abstract: A proximity sensor is disclosed having two bifurcate fiber optical bundles arranged in parallel. Light is directed at a target by the bundles and the reflected light from the target is transmitted to two separate sensors. The output difference of the sensors is used to derive a control signal for tracking a target. The control signal has a null point and is used in a servo loop to keep the bundles at a constant distance from the target.

Abstract: A displacement measuring instrument for measuring the displacement of a target including in combination a fiber optic lens assembly including means for maintaining said assembly in space relation with said target, dither means for vibrating said assembly toward and away from said target about the lens null along the axis of said assembly, first electronic means for providing a first output voltage proportional to displacement of said assembly from said target, second electronic means cancelling that portion of said first output voltage resulting from displacement due to said dither means and providing a second voltage resulting from displacement due to means other than said dither means, servo means receiving said second output voltage and moving said assembly with respect to said target to null said second output voltage and measurement means measuring the movement of said servo means.

Abstract: Provides new magnetic fluid bearings and magnetic fluid seals incorporating a pressure responsive system for automatically controlling the supply of magnetic fluid to the magnetic fluid feed area of such bearing or seal. The system for controlling the supply of magnetic fluid includes a reservoir of magnetic fluid and a conduit leading from the reservoir to the magnetic fluid feed area of the magnetic fluid bearing or magnetic fluid seal. A portion of the conduit is subjected to a magnetic field which establishes a pressure responsive magnetic fluid plug in that portion of the conduit to automatically control the flow of magnetic fluid to and from the reservoir as a function of the difference in pressure between the magnetic fluid feed area of the bearing or seal and the reservoir.

Abstract: Compensation for shaft excursion in a seal housing is achieved with a fluid film bearing in which bearing fluid is supplied to the bearing region at a pressure and flow rate which depend upon shaft rotational speed. In a disclosed embodiment, the bearing fluid is provided from a centrifugal fluid seal which delivers part of its fluid to the bearing region as a function of centrifugal pressure. A magnetic fluid seal is employed for zero and low speed operation. The shaft includes an annular collar which rotates in an annular cavity formed in a seal cartridge which is rotationally stationary but capable of small axial displacements to compensate for axial shaft displacement. A spring biases the cartridge in opposition to the axial forces of the magnetic fluid seal so as to axially balance the system at zero and low shaft speed operation.

Abstract: A two-tank working gas supply and pump-down system is coupled to a hot gas engine, such as a Stirling engine. The system has a power control valve for admitting the working gas to the engine when increased power is needed, and for releasing the working gas from the engine when engine power is to be decreased. A compressor pumps the working gas that is released from the engine. Two storage vessels or tanks are provided, one for storing the working gas at a modest pressure (i.e., half maximum pressure), and another for storing the working gas at a higher pressure (i.e., about full engine pressure). Solenoid valves are associated with the gas line to each of the storage vessels, and are selectively actuated to couple the vessels one at a time to the compressor during pumpdown to fill the high-pressure vessel with working gas at high pressure and then to fill the low-pressure vessel with the gas at low pressure.

Abstract: A seal arrangement is provided for preventing gas leakage along a reciprocating piston rod or other reciprocating member passing through a wall which separates a high pressure gas chmber and a low pressure gas chamber. Liquid lubricant is applied to the lower pressure side of a sealing gland surrounding the piston rod to prevent the escape of gas between the rod and the gland. The sealing gland is radially forced against the piston rod by action of a plurality of axially stacked O-rings influenced by an axially acting spring as well as pressure from the gas.

Abstract: A method of making a laminated stator assembly for a dynamoelectric machine which comprises machining an inner stator member as a single detail having a plurality of winding retaining grooves and plurality of radial slots all of which terminate at or near a central core portion of the stator member. The material between the radial slots form spaced apart radially tapered sections which terminate in the central core portion and the stator member can serve as its own winding mandrel for winding coils in place in the grooves. After such winding an outer shell of magnetic material is fitted over the inner stator member. The coils, spaces between the radially tapered sections, and surfaces of the groove are provided with suitable, electrically insulating bonding material which after curing bonds such elements into a single unit. The central core portion is then machined away so that there is longer a direct connection between the interior ends of the tapered sections and the stator member.

Abstract: A two piston Stirling engine which includes a heat exchanger arrangement placing the cooler and regenerator directly adjacent the compression space for minimal cold duct volume; a sealing arrangement which eliminates the need for piston seals, crossheads and piston rods; and a simplified power control system.

Abstract: A power control system for a hot gas engine of the type in which the power output is controlled by varying the mean pressure of the working gas charge in the engine has according to the present invention been provided with two working gas reservoirs at substantially different pressure levels. At working gas pressures below the lower of said levels the high pressure gas reservoir is cut out from the control system, and at higher pressures the low pressure gas reservoir is cut out from the system, thereby enabling a single one-stage compressor to handle gas within a wide pressure range at a low compression ratio.

Abstract: A mean pressure power control system for a hot gas (Stirling) engine utilizing a plurality of supply tanks for storing a working gas at different pressures. During pump down operations gas is bled from the engine by a compressor having a plurality of independent pumping volumes. In one embodiment of the invention, a bypass control valve system allows one or more of the compressor volumes to be connected to the storage tanks. By selectively sequencing the bypass valves, a capacity range can be developed over the compressor that allows for lower engine idle pressures and more rapid pump down rates.

Abstract: A multiple volume compressor for use in a hot gas (Stirling) engine having a plurality of different volume chambers arranged to pump down the engine when decreased power is called for and return the working gas to a storage tank or reservoir. A valve actuated bypass loop is placed over each chamber which can be opened to return gas discharged from the chamber back to the inlet thereto. By selectively actuating the bypass valves, a number of different compressor capacities can be attained without changing compressor speed whereby the capacity of the compressor can be matched to the power available from the engine which is used to drive the compressor.

Abstract: In a reciprocating machine, there is provided a hollow piston including a dome portion on one end and a base portion on the opposite end. The base portion includes a central bore into which a rod is hermetically fixed in radial and angular alignment. The extending end of the rod has a reduced diameter portion adapted to fit into the central bore of a second member such as a cross-head assembly, and to be secured thereto in radial and axial alignment with the piston.