Abstract: A capacitance to digital conversion system wherein condition sensing capacitors and reference capacitors are arranged with circuitry including a virtual ground and means for providing an error signal related to the sensed condition. The capacitors, virtual ground and error signal means are disposed within a sealed housing so that the system is isolated from environmental influences and is hence more stable than like systems known in the art.

Abstract: A special drive link permits drilling of holes of different diameters with the same drill drive. The drill shaft has a helical pattern of scroll-like projections for removal of cuttings. The drill drive mechanism includes sprockets carrying two chains of drive links which mate with the helical scroll projections to move the drill shaft axially, and projections on the drive links mate together at the center to hold the drive links tightly around the drill shaft. The drill shaft is formed with an elongated axial groove separating the helical projections and defining notch surfaces which mate with projections or tangs extending inwardly from the hollow portion of the drive links where they surround the drill shaft. Rotation of the mechanism results in transferring the rotating force through the sides of the inwardly extending projection of the drive links to the corresponding notch surfaces of the scroll projections.

Abstract: A rigging arrangement and yarder are disclosed for yarding in which a single cable is used. This cable is anchored at a main storage drum on a yarder and preferably at an anchor in the vicinity of the tail block. The single line serves as a running skyline for supporting a carriage and includes several loops around a tram drum and an idler drum (but only one layer on said drums) which operate to hold cable or to reel equal amounts of cable in or out to both the yarder side and the anchor side of the carriage to move the carriage without introducing slack into either side. Since only a single layer of cable is wound on the tram and idler drums, no energy is lost dealing with varying speeds and torques caused by changing effective diameters, thus saving energy and weight of equipment.

Abstract: A cable wiper assembly for airborne sonar includes a housing suspended from a hoist used to rapidly raise and lower a sonar transducer at the end of a cable. The wiper assembly is interposed ahead of the cable-directing sheaves forming part of the hoist to strip away the sea water which adheres to the cable as it is pulled from the ocean. The housing includes a plurality of wiper stages, each of which consists of a washer-like rubber wiper whose internal diameter is just slightly smaller than the cable diameter and a spacer having substantial thickness interposed between wipers with a centrally located well on one side and a flat surface on the other. Radial passageways at the bottom of the wells direct water stripped away by the wipers to the outside of the spacers. The housing includes means clamping the wipers and spacers together and also radial ports for discharging the water flowing away from the spacers.

Abstract: A readily separable fastening structure for holding a pair of cylindrical sections together in axial alignment includes annular rim members attached to the inside surfaces near the ends of the cylindrical members, one of which has an outwardly extending flange spaced from the end of its corresponding cylindrical member to form an annular groove and the other of which is adapted to telescope within the first such rim member, the other such rim member also including an inwardly extending flange. A plurality of spaced members having spring fingers are attached to the outside of the second cylindrical member and extending beyond the end thereof, the spring fingers each having an inwardly extending ridge and a groove on the outside of the ridge. A small diameter cable is positioned in said grooves, and tensioning members are included for pulling said cable tightly around said fingers to pull the inwardly extending ridges into said annular groove to lock said cylindrical members together.

Abstract: An underwater viewing system described herein substantially reduces the number of hydrophones in the receiving array and associated circuitry by providing a plurality of transmitting transducers spaced apart by a known distance, each emitting a coded output which is normally a separate frequency. The receiving array, which is preferably square or rectangular, includes a substantial number of receiving hydrophones.A synthetic aperture technique is applied in which the reflected signal arriving at each individual hydrophone is amplified, modulated with a lower frequency reference signal, filtered, digitized and stored in a memory, preferably as part of a computer. The computer also compares each digitized hydrophone signal against sine and cosine reference signals at each frequency and performs a Fourier analysis of each row and column to reconstruct a primary image.

Abstract: A microwave diplexer circuit consists of a stripline conductor carried between two dielectric substrate members, each having a conductive layer serving as a ground plane on its side nonadjacent to the stripline. The substrate members are enclosed in a housing of conductive material including a bottom which contains the substrate members and the stripline conductor, and a top which is fastened to the bottom to make an enclosed unit wherein the housing makes electrical contact with the ground planes. The stripline is formed with a pair of extensions in the form of grounding tabs which extend into small chambers not occupied by the substrate members. In the particular circuit shown, the circuit adjacent the grounding tabs is a high frequency microwave filter including a plurality of stubs. A shorting bar in each of the chambers overlies the tabs and is clamped to the wall of the chamber such that it defines a short at the desired length of each of said plurality of tuning stubs forming the filter.

Abstract: A dual mode high-frequency printed circuit radar antenna for aircraft use having good aerodynamics is provided in the form of a printed circuit antenna molded into a smooth, blade-like protective shield. The antenna, printed on an epoxy glass substrate carried on a mounting plate including, integrated in series, a stub monopole element and a larger area capacitive loading member for I-band reception, an inductive member whose impedance is very high at I band and a monopole element which adds sufficient length that the entire conductor track acts as a quarter wave length monopole at C and D bands. At I band the stub monopole element and capacitive loading is isolated from the added monopole element by the high impedance inductive member, making for good I-band performance.

Abstract: A varactor multiplier circuit is driven by a pulsed source of radio frequency and self-biased such that it operates in its snap condition to generate harmonic frequencies. The output pulse has essentially the same configuration and length as the input pulse. These pulse envelopes may have a relatively slow voltage build-up with time. A separate bias drive circuit is directly connected to the varactor and provides a negative-going pulse of sufficient voltage to bias the varactor to its off condition. This gating bias pulse is variable as to pulse width and is very steeply rising and serves to either turn on or cut off the varactor sharply to thus provide a shaped envelope of the output wave form. An isolating capacitor and a band stop filter operate to prevent loading of the multiplier circuit by the bias drive circuit and to prevent radio frequency leakage into the drive circuit.

Abstract: Multiple path means for a fluid flow control device is shown in connection with a typical spool type servo valve wherein the spool member moves within a stationary sleeve to control fluid flow to a piston in a cylinder. The multiple path means includes a series of stacks of washer-like elements or disks which are positioned in radial bores in the valve sleeve and which disks cooperate when the spool number moves a small distance from null to define a restricted path across the stack in which flow is forced through a series of alternating chambers and orifices with measured pressure drops across the orifices. Further movement of the spool member away from null opens a large parallel flow path. Since many servo valves have comparatively short travel and since both control and wear problems of such valves tend to be most serious near null, the restricted flow path is utilized to minimize abrupt step flow gains with the usual accompanying wear around null.

Abstract: Multiple path means for a fluid flow control device is shown in connection with a typical spool type servo valve. The multiple path means consists of a stack of washer-like elements or disks which cooperate to define a number of finely divided flow paths across the stack in which flow is forced through a series of alternating chambers and orifices with measured pressure drops across the orifices. Since many servo valves have comparatively short travel and since both control and wear problems tend to be most serious near null, it is desirable to minimize abrupt step flow gains around null.In the present disclosure individual disks, at least at the ends of the stack, are made comparatively thin such that the thickness of two or more disks may be required to provide a normal opening width into the stack.

Abstract: A fish counter primarily for counting migrating salmon in streams includes a narrow beamwidth side-scanning sonar transducer which is directed to insonify a volume of water in the stream directly above a mechanical structure serving as an artificial bottom. This structure consists of a lightweight, ladder-like frame with transverse support members of arcuate form over which is stretched a thin skin of sheet metal such as aluminum, thereby providing a structure of great stiffness to avoid sagging. The transducer is supplied with transmitting pulses of short duration at regular intervals. After a delay, a receiver is enabled to permit reception of echo signals returning from any fish crossing the artificial bottom. During the period the receiver is enabled, a ring counter separates the return echoes on the basis of the return time from respective sectors of the bottom structure, and these returns are separately counted for each sector to permit each sector to be read out separately or printed out separately.

Abstract: An anchor-deploying structure and method particularly adapted for anchoring an offshore drilling platform employs the use of an anchor, anchor chain and wire rope combination. Separate reeling and storage means are supplied for the wire rope and anchor chain, the wire rope being carried on and deployed from a winch-driven drum and the chain being carried in a chain locker and deployed from and returned to the chain locker by a chain hoist. At the end of the wire rope is a connector which carries a short length of leader chain which may include a swivel. A work station is so located that workmen thereon have access to both the leader chain and a length of lead chain from the chain locker, either of which may be connected to the anchor chain through the use of a special three-way chain link and a pair of removable links.

Abstract: A hydrophone configuration provides compensation for longitudinal accelerations by placing two essentially identical solid ceramic piezoelectric elements back-to-back against a centrally located bulkhead in a strong cylindrical metal housing. The opposite ends of the elements are bonded to end caps which are mechanically sealed to the inside walls of the housing. The inside walls are spaced from the elements to allow any radial expansion or contraction of the elements to take place into an air chamber which is effectively isolated from the input to the hydrophone which is axial against the outside surfaces of the end caps. In a second embodiment two pairs of parallel-connected piezoelectric elements are included for a higher capacitance.

Abstract: An airborne sonar system includes a transducer with both projecting elements and receiving elements designed for echo ranging at a moderately high frequency. Carried on the transducer housing is an additional hydrophone which is sensitive to sonar input signals at low frequency and, hence, which has a capability of responding to signals from much longer range than can the receiving elements of the echo ranging transducer. This low frequency hydrophone is sensitive to the frequency of much of the noise and vibration imparted to the transducer housing by the supporting aircraft and so, in operation, the hydrophone is suspended on a very compliant mounting consisting of a plurality of strips of light rubber tubing.

Abstract: Multiple path means for a fluid flow control device is shown in connection with a typical spool type servo valve and a relief valve. The multiple path means consists of a stack of washer-like elements or disks which cooperate to define a number of finely divided flow paths across a stack of disks. To provide a configuration which is very economical of space, the disks are arranged such that the flow path turns back and forth through different planes. Groups of flow paths are defined by a number of groups of perforated disks confined between the imperforate disks. Two perforated disks having patterns of openings are positioned on opposite sides of a similar disk having a pattern of small orifices.

Abstract: A stabilizing structure for a buoyant elongated cylindrical housing assembly is tethered to an anchor on the bottom of a body of water and includes a pair of positively buoyant arms hinged to the top of the housing at an angle to each other with leaf spring members and cables attached to the ends of the leaf spring members to limit the upward travel. The outwardly extending arms have an airfoil-like cross section and assume a trailing position relative to any current in the water with the current bisecting the angle between the arms. This arrangement causes the arms to exert a lifting force tending to both rotate the housing toward the vertical around its point of attachment with the tethering line attached to its lower end in opposition to the tilting force exerted by the current and also to positively lift the housing to a higher position more nearly over the anchor. A pair of tip fins may be used to counter forces tending to move the assembly in yaw.

Abstract: A hydrodynamic instrumentation or transducer structure is adopted for deployment into the ocean or similar large body of water in such manner that it is caused to descend essentially vertically from a buoy at the end of a line of substantial length, such as 1000 feet or more. The essentially cylindrical structure includes a cylindrical extension of essentially the same diameter as the primary structure whose purpose is to house at least the line and possibly also the buoy structure, as well as carrying a plurality of brackets at its outboard end which secure the outboard ends of a corresponding number of resilient fin members attached to the primary structure such that the entire assembly may be carried in a cylindrical space little larger in diameter than the primary structure.

Abstract: Quieting means for a fluid flow control device is shown in connection with a typical spool type throttling valve. The quieting means consists of a stack of washer-like members or disks which cooperate to define a large number of finely divided flow paths across the stack of disks. To provide a configuration which is very economical of space, the disks are arranged such that the flow path turns back and forth through different planes. Groups of flow paths are defined by a number of groups of three perforated disks confined between two imperforate disks. Two perforated disks having patterns of slots are positioned on opposite sides of a similar disk having a pattern of small orifices.

Abstract: A connector for a small diameter towed sonar array is used to couple similar sections together. Each section includes a sheath or tubing of flexible plastic material such as polyvinylchloride clamped at each end tightly around a cylindrical metal coupling member having threads extending external of said tubing. Held adjacent the internal surfaces of the coupling members at the outside ends thereof are a pair of connector members which include a plurality of concentric conductor tracks. When adjacent sections are joined, these conductor tracks are pressed tightly together, partly as a result of the force exerted by flexible plastic spacers which abut against internal shoulders of the coupling members and the connector, urging the connector members outwardly against each other.