Abstract: The assembly comprises first and second tracks of extruded polyvinyl chloride plastic which, when interfaced, become a hinged clamp. When snapped or clamped together, the tracks tighten and securely clamp fabrics of varying weights. By providing relatively elongated tracks, the installation of the fabric is greatly facilitated in that extended marginal edges of the fabric can be clamped in a single clamping motion. There is no need for a special tool requiring successive stuffing of the fabric into a biased slot and the labor and time involved therewith.

Abstract: The control valve is arranged to surround the anal-terminating descending intestine of a patient for realizing continence; that is function as an artificial sphincter. The valve itself comprises a stationary ring and a lower rotatable ring in an axially aligned position. A plurality of rods extends from the lower rotatable ring through aligned openings in the upper stationary ring. When the lower rotatable ring is rotated through an angle, the rods twist and their center portions radially contract inwardly in such a manner as to reduce the cross sectional area of the passage through the rings. By lining the rings and rods with a toroidal member, having an inner flexible part, rotation of the rotatable ring by an appropriate reversible drive motor will gently close off or open up the descending intestine portion of the patient.

Abstract: The paint shield comprises a thin rectangular sheet with a longitudinal crease extending in from one end terminating short of the opposite end. A transverse crease is provided which intercepts the longitudinal crease. The arrangement is such that a portion of the shield can be bent about the transverse crease to protect areas intersecting at an angle from paint, such as corner molding and the like. By flexing the shield about its longitudinal crease, the bent portion automatically snaps back into a coplanar relationship with the remaining portion of the sheet so that its maximum longitudinal length is again available for shielding while painting. Notches can be cut out from opposite ends dimensioned to snugly engage 2.times.4 inch rafters or 2.times.6 inch rafters to protect surrounding wall areas when painting the rafters.

Abstract: The water heater has a totally submerged combustion chamber disposed within the lower third portion of the tank. Top and side openings connect respectively to an upwardly extending flue pipe and an inlet side cylinder to provide an air and gas passage through the tank in heat exchange relationship with water. A gas burner is receivable in the combustion chamber and is operated by a thermostat to assure a continuous supply of hot water. The totally submerged combustion chamber itself is solely supported by the flue pipe and side inlet cylinder.

Abstract: A sub incorporating a check valve is connected into the lower end of a well pipestring. This valve will pass hot steam injected down the pipestring to the formations to loosen up the thick crude oil. The check valve prevents back flow and thus will hold the high pressure steam. To resume production, the production pump can then be lowered through the pipestring. The pump itself is provided with an extended probe member which will unseat the check valve when the pump is in proper position so that production pumping can resume.

Abstract: The conversion is effected by adding equal and opposite reference voltages to the analog signal to provide two first output voltage levels. The voltage difference between these levels is converted into a first given number of pulses. The polarity of the analog signal is then reversed during the second half of the cycle so as to be subtracted from the reference voltages for providing two second output voltage levels. The voltage difference between these levels is converted into a second given number of pulses. A function of the first and second number of pulses provides a numerical count directly proportional to the analog signal and because of the bipolar operation; that is, the switching of the polarity of the analog input signal, all zero drift is eliminated.

Abstract: A cylindrical bushing is positioned over the shank of a screw member prior to forming threads on the shank. After the threads are formed, the outside diameter of the threads is greater than the inside diameter of the bushing so that the bushing is held captive on the shank of the screw. A cylindrical sleeve is then inwardly deformed so as to be permanently secured to the bushing. The opposite end of the sleeve facing away from the head of the screw shank extends beyond the bushing and forms a skirt which can be peened over the peripheral inner edge of a panel opening to secure the sleeve to the panel, thereby holding the screw captive to the panel. The end of the bushing next to the underside of the screw head has an increased internal diameter portion for accommodating a spring serving to bias the head and shank away from the bushing so that when the screw is unfastened, it will pop outwardly and release quickly any member to be secured to the panel.

Abstract: The adapter is arranged to be mounted to the horseshoe travelling carriage for a weld head in a pipe welding system to support the torch or weld head at an acute angle to the plane of rotation of the travelling carriage and thus to a plane normal to a pipe axis. This positioning of the weld head or torch facilitates socket welding; that is, welding about the intersection point of larger and small diameter pipes. The adapter comprises a mounting plate and a movable plate supported at an angle to the mounting plate by appropriate guide rods. Left and right racks adjacent to the guide rods and secured to the movable plate are driven by a single pinion bridging the racks and mounted between fixtures secured to the mounting plate. The movable plate is constrained from movement in a plane parallel to itself by the guide rods. A motor operates the pinion so that the weld head can be moved closer to and further from the socket area to be welded as appears necessary to effect a high quality weld.

Abstract: The sling-shot apparatus includes a handle with lateral arms to which an elastic cord is attached to form a sling. A projectile holding member is connected to this sling and also, a guide structure provided for guiding the movement of the projectile holding member along a rectilinear path when the elastic cord is stretched and released. Sighting members can be provided on the guide structure so that much greater accuracy is possible with the sling-shot.

Abstract: A normally closed drain valve is substituted for the normal drain plug in a conventional automobile crank case. Rather than remove the normally provided drain plug each time the oil is to be drained, it is only necessary to open the drain valve. Opening of this valve is accomplished by a specially designed coupler connected to a plastic bag. The arrangement is such that when the coupler is urged over the drain valve and twisted, the valve automatically opens to fill the bag with oil. The coupler can then be twisted back to its original position to close the drain valve and removed with the bag containing the oil. The entire operation can be accomplished only using one hand and with substantially no risk of oil spilling or soiling the operator.

Abstract: A pipe clamping structure is arranged to clamp an in-place pipe to be welded. A welding mechanism in turn is coupled to the pipe clamping structure for rigid guided movement in directions parallel to itself towards and away from the clamping structure in an axial direction along the pipe. The welding mechanism in turn supports a horseshoe-shaped weld head support rotor which receives the pipe in the horseshoe opening and is arranged to rotate about the pipe axis. A torch head is carried on the horseshoe rotor so that a 360.degree. weld can be achieved and simultaneously, the welding mechanism can be oscillated back and forth by the rigid guidance and alignment coupling with the clamp structure. In addition, the torch head is held on a link plate to the rotor, the link plate being swingable to vary the arc gap and thus provide appropriate voltage control.

Abstract: The cross-piece portion of a tubular T-joint has a cross-section of constant inside diameter from one end of the cross-piece to the other and increasing outside diameter from one end towards it center, then decreasing from its center towards it opposite end to define a double tapered tube wall for the cross-piece of maximum thickness at its center. A stem portion for the T-joint is in the form of a hollow tube extending normally away from the center portion of the cross-piece to terminate in a free end. The cross-section of the stem has a constant inside diameter from its free end to its point of interception with the cross-piece and an outside diameter increasing from its free end to its point-of-interception with the cross-piece so that the maximum thickness of the T-joint is at the interception between the cross-piece and the stem and yet the inside diameters are all uniform so that other tubes can be readily telescoped through the cross-piece.

Abstract: A pipe section with an exteriorally secured valve body is arranged to be inserted in a lower portion of a well pipe string containing sucker rods and a lower pump, the pipe section and valve body being disposed slightly above the pump itself. A lateral pin passes through a connecting bore between the pipe section and valve body and is arranged to be urged in a lateral direction to operate the valve when the sucker rods are moved beyond their normal stroke within the pipe string. Opening of the valve serves to place the column of fluid in the well pipe string into communication with the well annulus and thereby permit emptying the pipe string of the fluid column and thus permitting the pipe to be pulled for repairing the pump or for other operations without the disadvantage of the heavy hydrostatic pressure resulting from the fluid column.

Abstract: A casing with common padded first and second cavities holds two self-contained, battery-operated, commercial, digital-electronic pocket-calculators in a removable fashion. The "equal/repeat" keys of both calculators are brought out to calculator-embedded contacts by the manufacturer. The casing further includes a rocking rod, two micro switches, a battery and a control circuit. The control circuit develops "shorts" spaced by one second time intervals. The calculators are used as time-pre-programmed, decrementing, by seconds, time, scorekeepers as the shorting pulses are applied to the one calculator whose owner's move it is in a game of speed chess. The calculators and other parts are consumer-replaceable.

Abstract: Two operational amplifiers are hooked in a different mode by unique circuitry so that the common mode gain is unity and the open loop gain is the same as the open loop gain of the individual amplifiers. Essentially, a negative feedback network feeds the common mode output signal back to the negative input terminals which cancels the common mode output signal. Practical applications are achieved by adding appropriate integrating capacitors between the output and negative inputs of the amplifiers with appropriate series resistances in the input leads.