Abstract: A plurality of different frequency signals f.sub.1, f.sub.2, f.sub.3, . . . fn are combined for transmission in a common transmission line by a series of hybrid circuits each including a through coupler for feeding through frequency signals through the hybrid circuit to the output thereof, an injection coupler for feeding an injected frequency signal to the hybrid output and one or more tuned circuits between the couplers that are tuned to the frequency of the injected frequency signal and connected to the couplers by a stub transmission line of electrical length in terms of wave lengths of the through frequency, so that substantially all power of the through frequency signal and all power of the injected frequency signal flow from the hybrid circuit output to the next hybrid circuit in the series.

Abstract: A heated mold panel for casting concrete has a rigid base providing a base surface, a substantial part of which is grooved by interconnecting grooves, has a continuous heating element laid in the grooves, and the base surface is covered with a non-porous, non-corrosive material that provides a smooth outside surface covering the base surface, spanning the grooves and enclosing the element in interconnecting passages defined by the grooves and the covering material. Sufficient clearance is provided in said passages around the element for air to flow freely from passage to passage, whereby heat flow from the element to the concrete poured against the outside surface is by radiation from the element and by convection of air flowing in the passages around the element.

Abstract: In a Loran Receiver that receives radio frequency (RF) signals from a master beacon and at least two slave beacons (also called secondary transmitters) and converts the received signals into hyperbolic coordinates that locate the position of the receiver with respect to the beacons and a programmed computer controls modes and sequences of operation of the system, these modes being generally the beacon pulse search mode, front edge/zero crossing location mode and the zero crossing track mode, received beacon pulses are searched and identified by the following technique: all received signals are repeatedly sampled at the beacon group repetition interval (GRI) in a regular sampling pattern in which the sampling rate is greater than the beacon pulse rate, each sample interval being only a small portion of a beacon pulse RF excursion; the samples are hard limited and assigned a value of plus or minus, depending upon whether they exceed a threshold, and these plus-minus patterns are accumulated over many GRIs and s

Abstract: An electronic computer for computing and displaying the scores of the parties engaged in conventional games of Bridge receives inputs before each hand of the winning bid, the party winning the bid, and whether the winning party is doubled or redoubled; and upon completing the hand, the computer receives inputs of the number of tricks taken during the hand by the party winning the bid and honor points awarded to either party; and the computer computes and displays whether either party is vulnerable, the total point score of each party and the partial scores of each party.

Abstract: A four port directional coupler using two substantially identical transformers, each transformer having a turn ratio N with a substantially pure resistive impedance across both of the transformer's secondary windings and a substantially pure resistive impedance connecting the transformer's primary windings, whereby the coupling coefficient, C, of the directional coupler is a function of the said resistive impedances and N and is substantially a continuous function of the values of said resistive impedances for any independently selected value of N.

Abstract: A rotary piston mechanism for internal combustion engines, fluid motors, pumps and the like has an outer body enclosing a chamber that is defined by curvilinear walls that circumscribe the chamber axis, and a generally elongated rotor is confined in the chamber and rotatably supported by a rotor carrier that closes one end of the chamber and is rotatably supported on the chamber axis by the outer body so that the rotor rotates on the rotor axis which is parallel to the chamber axis and around the chamber axis over a closed path, the sense of rotation of the rotor on the rotor axis being opposite to the sense of rotation of the rotor axis around the chamber axis, and the rotor is oriented on the rotor axis by a gear train between the rotor and the rotor carrier.

Abstract: The electrode assembly of a galvanic cell for detecting and measuring small amounts of oxygen absorbed by the assembly is a symmetrical sandwich mounted on an anode plate or blade and including contiguous with the blade on each side thereof a porous anode carrying an anode material such as cadmium covered with a sheet of non-reticulated, porous, non-conductive, electrolyte retentive material wrapped around the blade, a cathode conductor strip wrapped around the sheet of electrolyte retentive material, a sheet of porous cathode material, such as graphite cloth wrapped around that and secured in place and the assembly is immersed in electrolyte, electrically charged and sealed inside an oxygen-free envelope.

Abstract: A remote transmitting or receiving device (T/R device) communicates with a conventional subscriber telephone through available AC power wires which carry signals that may be modulations of RF carrier frequencies and which are coupled to the power wires. For example, an incoming telephone call includes signals that are detected and modulate a master RF carrier frequency which is coupled to the AC power wires at the telephone line location and these signals are coupled from the AC power wires at a remote R device location, and, demodulated and used to control an electrical appliance, motor, pump, etc. The remote T device which may be, for example, a fire detector produces signals which modulate a remote RF carrier frequency which is coupled to the AC power wires at the remote location and this modulated carrier is coupled from the AC power wires and demodulated at the telephone line location to control or initiate signals in suitable form for transmission over the telephone line.

Abstract: A clamp for holding an ice skate while grinding the edge of the ice skate blade slides on a surface parallel to the plane of a grinding wheel for grinding the edge of the blade, the clamp holding the skate blade parallel to the plane of the grinding wheel, even with the edge of the wheel, so that the edge of the blade can be brought to bear on the edge of the grinding wheel along the length of the blade by sliding the clamp about on the surface; and so long as the clamp is against the surface, the edge of the blade is aligned with the edge of the grinding wheel.

Abstract: A cushioned liner that fits inside a bath tub has a back cushion provided by a flexible water bag conforming to the back of the tub and left and right side cushions provided by flexible bags conforming to the left and right sides of the tub, the bags being connected together end to end and across the bottom of the tub by a bottom portion that conforms to the tub bottom. The insides of the bags are interconnected and all are filled with water through a common filling hose after installing in the tub and before the tub is filled with water for bathing. When the tub is drained, the bags can be drained through one or more drain plugs and openings in the bottom of the liner are provided to permit draining.

Abstract: A wheelchair with relatively large diameter wheels on each side of the chair frame and two smaller wheels in front carries one or more continuous traction belts beneath the seat and/or the back of the chair in retracted position when the chair is used on a flat surface. The large wheels are each attached to the frame by a lever controlled mechanism manipulated by the operator to raise the large wheels, lowering the seat and tilting the chair backward so that the chair rides on the continuous traction belts. This action is taken at a steep incline or at steps to place the operator in a safe, comfortable position with lowered center of gravity for ascending or descending the steps. Means such as an electric motor is provided for driving the traction belts to carry the operator safely up or down the incline or steps.

Abstract: An electrical system for automatically measuring, computing and indicating the oxygen content in a sample of fluid, using a galvanic cell that absorbs and consumes the oxygen from the sample, produces controlled current pulses of given duration that are conducted by the cell as necessary to maintain the cell voltage constant and these pulses are counted during controlled intervals and the count is displayed as a representation of the oxygen content of the sample.

Abstract: The picture frames recorded on video magnetic tape are identified by serial binary numbers magnetically recorded along an edge of the tape. The sequential ONE and ZERO bits that form each number occur during equal successive intervals when the tape is transported at constant speed and these bits are detected as electrical pulse excursions, one pulse excursion during the interval for a ONE and no excursions during an interval for a ZERO. The pulses are detected even while the tape is not transported at constant speed as when it is accelerating or decelerating and so, the intervals for the successive binary bits may change rapidly and when that occurs, it is difficult to determine whether the successive excursions define a binary ZERO interval or the first half of a binary ONE interval and so, it cannot be determined whether they represent a binary ONE or a binary ZERO.

Abstract: Transparent marker pieces for use on a game board such as the game of Bingo and the like contain magnetically permeable material so that they can be quickly and easily gathered up from the game board with a magnet attached, for example, to a pencil or pen used by the player and then simply wiped off the pencil and deposited in a container for the marker pieces. In the preferred construction, the magnetically permeable material in the marker does not substantially block the view through the marker of the game board beneath and so, the transparent quality of the marker is maintained.

Abstract: A rotary piston mechanism for internal combustion engines, fluid motors, pumps and the like has an outer body enclosing a chamber that is defined by three equal curvilinear walls that circumscribe the chamber axis and define an equilateral triangle in a plane perpendicular to the chamber axis, the walls being convex with respect to the axis, and a generally elongated rotor confined in the chamber of length equal to the span of the chamber along a bisector of any of the angles of the equilateral triangle defined by the chamber walls, the rotor being pivotally supported to rotate about a rotor axis which is parallel to the chamber axis and moves around the chamber axis over a closed path, the sense of rotation of the rotor on the rotor axis being opposite to the sense of rotation of the rotor axis around the chamber axis.

Abstract: A basic electrical switch for switching alternating (frequency) electrical signals between four symmetrical switching terminals generates, in response to command signals, any of a plurality of switch patterns which provide simultaneous transmission paths between terminals of different pairs and isolation between terminals of different pairs. The switch consists of four hybrid couplers and four reflection-type phase shifters, which are arranged so that the input signal to a coupler is divided equally into two parts, each of which undergoes proper phase shifts by the command signals to emerge from the desired output terminal, either in phase for transmission or out of phase for isolation of the signal. Within each switching state, the signal can also be controlled in biphase by the command signals. The terminals are matched to the characteristic impedance of the switch under any switching state and so, a plurality of such basic electrical switches can be connected at their terminals to provide an "M .times.