Abstract: A loudspeaker with a pair of speaker units and a manifold chamber between the speaker units for combining the sound from both speaker units. The manifold chamber is formed by walls having an exit opening and a pair of rectangular apertures, the apertures confronting each other on opposite sides of the chamber and the exit opening being disposed normal to a plane centrally between the apertures, and the apertures and exit opening having parallel axes of elongation. One of the speaker units is coupled to each of the apertures to direct sound into the manifold chamber, and the manifold chamber is provided with a wedge confronting the apertures to direct sound parallel to the central plane between the apertures toward the exit opening. In one construction, a horn is coupled to the exit opening to conduct sound from the manifold chamber.

Abstract: A paint spray booth with a filter and means within the spray booth to incinerate paint from the filter. A filter particularly adapted for collecting paint overspray in a paint spray booth. The filter has a plurality of members with a first portion parallel to the path of the air and paint particle flow which is to be filtered, each of the members having a second portion extending normally in a first direction from the downstream side of the first portion. The second portions of the members are spaced from each other and form openings therebetween on a plane normal to the flow of air and paint particles. Each of the members has a third portion extending from the other side of first portion and in the opposite direction from the second portion, and the third portions of the members form slots between members with areas less than the area of the downstream openings.

Abstract: The process of molding thermal insulating blocks and electrical heating units with a mold having a horizontal filter screen in which a slurry containing a mass of inorganic fibers, water, and a binder is mixed to randomly orient the fibers and thereafter poured into the mold to divide the liquid component of the slurry into a first portion and a second portion, the first portion of the liquid component of the slurry being drained through the screen and the second portion remaining with the fibers, thereafter vibrating the screen and mold to drain a portion of the second portion of the liquid component of the slurry through the screen to produce a filter mat, thereafter drying the filter mat to remove the remaining liquid component of the slurry from the mat, and thereafter heating the filter mat to bond the fibers to each other. An electrical heating element may be mounted on the mold before the slurry is introduced into the mold.

Abstract: A device for holding and supporting a tire casing during servicing, and for spreading the casing of a tire so that the inner tube may be removed. The device includes a stackable cylindrical base having diametrically opposite cut-outs to accommodate a tire casing, a platform extending between the cut-outs to support the casing, and two hooks pivotally mounted on the cylindrical base diametrically opposite each other to engage and spread the tire casing. A pivotally mounted lever arm displaces one of the hooks from an engaged position to a non-engaged position.

Abstract: A sail propelled vehicle for land or sea in which a triangular yoke is pivotally attached at two of the corners thereof on two pontoons, skis, or skateboards at the forward ends thereof. The mast for carrying the sail is mounted vertically on the yoke at the third corner thereof. The operator is carried on the two pontoons, skis, or skateboards and by exerting force thereon through his feet and legs, the operator can pivot the yoke to position the sail on either side of the pontoons, skis, or skateboards to achieve improved stability, maneuverability and control.

Abstract: An endless loop tractor drive mechanism has equally spaced pushers meshing with a bucket train where its filled circular buckets are traveling along a substantially straight ascending path to a dumping support wheel. Wire rope cables or other flexible tension elements extend between the buckets. The pushers have drive rollers for pushing the buckets, and additional rollers for guiding the cables. Additional support wheels guide the bucket train along a catenary loading span where the buckets are dragged through bulk material to fill the buckets. At least two pushers engage at least two successive buckets at all times, to distribute and share the lifting load among two or more buckets. Due to the straight ascending path, the cables are not flexed when the lifting load is applied. Thus, the combination of high tensile stresses and high cable flexure is avoided. Wear and tear on the cables are thereby minimized. Fraying and breakage of the cables are no longer problems.

Abstract: An engraved plastic article is prepared by applying a coat of epoxy resin paint to a polyether sulfone resin article, curing the coated article at an elevated temperature, and engraving indicia on a surface of the article. During engraving the paint coating does not loosen, chip or otherwise dislodge.

Abstract: The disclosed pushbutton operated automotive air control unit incorporates a unique snap-action electrical switch in which the movable contactor has a combination of sliding and rocking movement. The contactor is rockably supported on a fulcrum member which is movably mounted on the slidable carriage. The fulcrum member includes a locating projection, loosely received in a slot formed in the contactor. A coil spring is interposed between the carriage and the fulcrum member for biasing the contactor toward a first fixed contact. There is also a second fixed contact having contactor rocking lugs for slidably engaging the contactor, as the carriage is moved between first and second positions. In the first position, the lugs engage a portion of the contactor which is on the remote side of the fulcrum member from the first fixed contact, whereby the contactor is rocked into electrical engagement with the first fixed contact.

Abstract: The position indicating device is employed to assist in parking and otherwise positioning a vehicle on a supporting surface. A photoelectric control unit is mounted on an overhead structure spaced above the supporting surface and has a beam emitting device for directing a light beam downwardly for interception by the vehicle, while minimizing the likelihood of interception by pedestrians, pet animals and other moving things. The light beam is initially reflected back to a photoelectric transducer on the control unit by a reflective device or mirror. The light beam is pulsed so that the transducer supplies electrical pulses to an amplifier which is correspondingly gated. When the light beam is interrupted by the vehicle, the amplifier produces a beam interruption output signal which causes a one-shot timer to energize an alarm device, through an output relay. The operator then stops the vehicle in the desired position. The one-shot timer de-energizes the alarm device after a brief interval.

Abstract: The disclosed pushbutton operated automotive air control unit incorporates a non-latching pushbutton switch for causing momentary switching of a control circuit, such switch being pre-assembled as a cartridge for easy insertion into the housing of the control unit. The switch comprises a pushbutton member which is telescopically engaged with a body member for sliding movement of the pushbutton member between extended and depressed positions. A return spring is interposed between the pushbutton member and the body member. The pushbutton member has a rearwardly projecting finger affording a switch carriage, slidably received in a guide channel in the body member. An electrically conductive contactor is mounted on the carriage and is selectively engageable with first and second fixed contacts mounted on the body member along such channel.

Abstract: A lounge chair with a beach mat resting upon the lounge chair in which the beach mat has a flap at one end which extends for a distance of 1/5 to 1/6 of the length of the beach mat and which accommodates the end of the back of the lounge chair to secure the beach mat on the lounge chair. The mat may be removed from the lounge chair and folded on the side of the flap four or five times to provide a flat roll, and folded one additional time to place the mat in the flap. The flap may thereafter be folded along the longitudinal axis of the mat and fasteners are provided to secure the mat in folded position, thus exposing the open end of the flap to receive articles.

Abstract: Novel compositions are disclosed for the manufacture of gunning mixes and strong castable products for use as monolithic refractory and construction materials which may contain no lime bearing cements. Bonding is based on the setting reaction of fumed silica with an alkali metal silicate preferably a particulate sodium or potassium silicate that slowly dissolves in water such as an anhydrous sodium silicate of SiO.sub.2 :Na.sub.2 O molar ratio of 1:1 to 4:1; or an anhydrated potassium silicate having an SiO.sub.2 :K.sub.2 O molar ratio of 3:1, or a hydrated sodium silicate having an SiO.sub.2 :Na.sub.2 O molar ratio of 3:1. Setting and mechanical characteristics allow this class of castable and gun mixes to be placed more rapidly into service since the time required for curing is much less. Although initial set strengths are not as high as those of conventional castables, very high strengths can be made to occur shortly after setting by heating.

Abstract: A method and apparatus for detecting the end of charge of a battery includes the steps of periodically changing, for a predetermined time period, the magnitude of charging current to a battery or bank of batteries, during each such predeterimined period, measuring the voltage drop across the battery or batteries until a predetermined level is reached, and producing an "end of charge signal" in response to the predetermined level of voltage drop being attained.

Abstract: A radio communications system operational within the medium frequency range for underground mine communications, coupling MF carrier signals into existing conductive channels extending to within the mine and devices within the mine and coupled to the conductive channel for receiving the MF carrier signals and communicating with portable and mobile transceivers operational within the MF frequency range and in the common seam mode.

Abstract: A power selector assembly for a loudspeaker includes in one embodiment an audio transformer upon which a printed circuit board (PCB) is mounted via connector strips having pins for both securing the PCB to the transformer, and for individually electrically connecting foil contacts of the PCB to the multi-tapped primary and the secondary windings of the transformer. The transformer is mounted within a housing. An electrical wiper contact is resiliently mounted between the PCB and a knob retained in an access hole through the housing, for permitting the knob to be rotated for positioning the wiper contact to selectively electrically connect a foil terminal receiving an input signal to one of a plurality of contact foils of the PCB, for connecting the input signal to one of the taps of the primary winding associated with a desired power level. Other electrical connections on the printed circuit board provide for connecting a loudspeaker to the secondary winding.

Abstract: A differential pressure actuator includes two fluid containing bags mounted on opposite sides of a support bar, and one of the bags is coupled to a load by means of a plate at the side of the bag opposite the bar. The other bag is also coupled to the load by means of a second plate mounted at the opposite end of the other bag, and the second plate is mechanically connected to the first plate by rods. Both of the bags contained a pressurized fluid in excess of atmospheric pressure, and the difference in the forces generated by the two bags is impressed upon the load. The load is a movable roller in a ringer for coating steel, and the movable roller is provided with separate actuators at opposite ends of the roller.

Abstract: The sealed toggle action switch comprises an operating lever having a front operating arm projecting out of the front component of the casing. The lever has a rear arm, projecting into the casing and carrying a contactor plate for relative sliding and swinging movement. A coil spring is received around the rear arm and is compressed between the contactor plate and the front sealing flange of a soft resilient sealing boot, such sealing flange being compressed against the operating lever. The boot has a rear, outwardly projecting sealing flange which is retained between the front and rear casing components. The contactor plate has a pair of J-shaped flanges which are slidably engageable with first and second fixed contacts having forwardly projecting protuberances, affording a detent action with the J-shaped flanges. In one position of the operating lever, the J-shaped flanges of the contactor plate engage both of the first and second contacts.

Abstract: A filtering media for use with edible liquids consisting of 80 percent synthetic amorphous silica, 10 percent synthetic amorphous magnesium silicate, 9 percent diatomaceous earth, and 1 percent synthetic amorphous silica-alumina. The process of rejuvenating spent cooking oil by admixing the filtering media in the spent cooking oil, maintaining the mixture at a temperature of 275.degree. F. for a period of about five minutes, and filtering the mixture to remove particulate matter including the filtering media.

Abstract: The mechanism comprises a blower speed control lever for operating at least one electrical switch, supported by a mounting bracket which has a place for a second switch. The speed control lever has rearwardly facing rocker shaft elements which are pressed against forwardly facing semicircular bearing recesses on the switch mounting bracket. The pressure is developed by flexible flanges which project rearwardly from a mounting panel and are engageable with forwardly facing tapered shaft elements on the speed control switch. The flanges are flexed to produce a spring action. Additional guard flanges project rearwardly from the panel, into adjacent relation with additional shaft elements on the speed control lever.

Abstract: A capacitor is charged to a high voltage, and then is discharged through a circuit comprising an analytical spark gap and first and second inductive elements, whereby the discharge current is oscillatory. The waveform of the discharge current is modified by a diode rectifier shunted across the series combination of the analytical spark gap and the second inductive element. To provide for adjustment of the waveform over a wide range, the second inductive element is adjustable in inductance. The first inductive element is also preferably adjustable in inductance. Provision may also be made for changing the capacitance of the capacitor. A reversing switch makes it possible to reverse the polarity of the diode rectifier. One or more control spark gaps may be connected in series with the analytical spark gap. An electronic switching device may be connected across one of the control spark gaps to initiate the discharge of the capacitor.