Abstract: This invention relates to a perspective drawing machine and more particularly, to a machine which will keep track of a chosen vanishing point. This invention describes a mechanical machine in which the corrected voltage is computed on an external calculator or computer, which when found on the output potentiometer will result in the correct line pointing at the invisable vanishing point.

Abstract: Objects constituted by a porous web-like material, such as a paper web, a granular material, such as peat, or a solid material such as wood, are dried by placing the same in contiguity with a fine porous liquid suction surface which itself is in liquid communication with a liquid volume with the latter being in communication with apparatus by which the liquid in the liquid volume is maintained at an underpressure relative to the pressure of the liquid in the object to be dried so that liquid flows from the object into the fine porous suction surface. The liquid flow can be enhanced through the application of an over pressure or through the direction of radiation onto the object to be dried. In one embodiment, the fine porous liquid suction surface comprises the surface of a rotatably mounted cylinder whereby a web-like object, such as a paper web, can be dried as the same is carried on the cylinder surface.

Abstract: A method for removing water from water base can end lining compound after application without the use of a dryer. The method comprises the steps of arranging the lined can ends in a stack, wrapping the stacked can ends in a suitable absorbent material, and allowing the absorbent material to remove the water from the compound by absorption.

Abstract: Apparatus is provided for drying pulverulent material, for example, coal slurry wherein the slurry, after preliminary drying, is introduced into a vibrating chamber carrying internal flights and subjected to vacuum to remove moisture. A pair of such containers may be provided so that slurry may alternately be introduced into one container while the other container is vibrating under vacuum so as to provide a continuous drying method.

Abstract: Disclosed is apparatus designed primarily for enameling the internal and external surfaces of pipes including a drying chamber constructed as three vertical coaxial tubes, viz. an outer tube, an intermediate tube and a center tube, each having an individual hot air feed. The center and intermediate tubes are provided with holes in the upper part thereof and form an annular working space of the drying chamber. Movably mounted in said working space is a circular support for the pipe under treatment. This support is kinematically connected with a counterweight which is movably mounted inside the center tube and is constructed as an upside down cup with radial channels in the wall thereof.

Abstract: An apparatus for controlling the ventilation effect on material dried in a tunnel drying plant, through which goods in the form of architectural ceramic structures, such as of bricks or tiles, to be dried and placed in layers, are moved in counter-current relation to an air current. The tunnel drying plant is designed with doors at the goods inlet and outlet ends. At the goods outlet end there is a pipe connection for blowing air under gage pressure into the plant, while at the goods inlet end and the top part of the tunnel drying plant there is an aspiration opening with an aspiration pipe connection. In the free cross-section of the flow tunnel drying plant, near the roof, there are air guiding bodies, which may be moved backwards and forwards in the length direction of the plant using cars on rails. These air guiding bodies are hollow and have a streamlined form.

Abstract: A sports shoe has a sole assembly with cylindrical recesses which grip longitudinally slit generally cylindrical shells of slightly larger initial diameter. The projecting ends of these shells can serve as attachments for gripping elements such as studs, attached thereto for example in the same manner. Alternatively, these projecting ends can be so shaped as to constitute integral gripping elements.

Abstract: A submarine vehicle for collecting and raising materials resting on the sea bed at great depths, of the type comprising a load-bearing structure, collecting elements for the materials, storage silos for storing the materials collected and/or the ballast material, transfer means between said collecting elements and said silos, and main propellers for advancing the vehicle on the sea bed, said vehicle being characterized in that said load-bearing structure is made of a buoyancy material, said structure being in the form of a ring having a longitudinal plane of symmetry and defining the stem, stern and sides of said vehicle, and defining between them a free central space, the outer surface of said structure forming the hull of said vehicle, said storage silos being arranged in the free central space and fixed to said load-bearing structure, said collecting elements being arranged in front of and below said stem, said main propellers also being fixed to the lower surface of said load-bearing structure.

Abstract: An improvement is provided in apparatus for securing overlapped portions of two members together. In addition to a wedge conventionally inserted in holes generally axially aligned in the overlapped portions, a locking bar is provided for insertion longitudinally in the holes and has a notch with opposed faces for tightly engaging the outer surfaces of one of the members which is subject to less flexing movement than the other. The wedge and bar are secured together after insertion to prevent loosening of the wedge in service.

Abstract: A snow plow side wing assembly is provided which is hydraulically operated and simply constructed such that it can be easily scaled down for mounting on a lightweight pickup truck. The assembly includes a wing blade, a lightweight frame adapted to be mounted to a vehicle, a pair of upstanding posts mounted fore and aft of the frame with each post including track means and a travel carriage mounted for sliding movement in the track means, and a hydraulic piston and cylinder arrangement mounted on the opposite side of the post to the track means with the cylinder mounted to the base of the post and the cylinder extending upwardly from the cylinder parallel to the post and connected to an extension arm extending parallel to the post and connected to the carriage. Two supporting arms extend from the carriage, both supporting arms being pivotally articulated to the carriage and to separate points on the end of the blade.

Abstract: The disclosure herein describes a name plate system consisting of a base plate provided on one face thereof with guide rails on which indicia bearing cover plates are adapted to engagedly slide; a pair of locking bars mounted at each extremity of the base plate serve to hold the cover plate to the base plate; a resilient retainer element mounted to the base plate serves to secure the locking bar in engagement with the base plate; the base plate is cut from a modular base plate so patterned as to allow various sizes of base plates to be cut.

Abstract: An improved display card holder, adapted for use in bulletin boards, as in arrival and departure boards for airlines, characterized by a retaining channel, in a base member, adapted to slideably receive a linear display card element, and a latch lever arm with a head extending through an opening in the base, which head is resiliently mounted and abuts against and arrests lateral motion of the display card element, so as to detachably secure the display card in the retaining track. A feature of the invention is that the operative elements of the latch are concealed and secured from tampering. A further feature of the invention is that its separate elements may be assembled or removed from the holder without the use of hand tools or fasteners.

Abstract: A picture frame for photographic snapshots having a rotatable easel of thin, lightweight construction mounted to the back side of the picture frame. The easel has a substantially trapezoidal shape when folded and has rectangular front and back panels having a common top edge and collapsible, triangular side panels interconnecting the front and back panels. The side panels may be folded, collapsing the easel into a flat structure for easy packaging and shipment. The side panels when unfolded form an easel for holding the picture frame in a stable, secure, upright position on a tabletop. The easel design of the invention produces an unusually stable structure for its weight. It does not collapse upon moving the picture frame in any direction on the table surface. The easel may be rotated to permit display of snapshots in either a horizontal or vertical orientation.

Abstract: A control panel for a microfiche reader includes an alphabetic keyboard having a plurality of buttons arranged in parallel rows and a numeric keyboard carrying numeral index images. Each row of the buttons is provided with an index carrier carrying a plurality of indicia. Each of this indicia corresponds to a row of images extending along one of the coordinate axes. These index carriers are switched to a plurality of positions to thereby align the respective indicia with the associated button which is pushed to locate the row of images in which the individual image to be retrieved is located. The second keyboard is thereafter used to locate the individual image in the row of images found by the first keyboard.

Abstract: An optical filter transforms defined color light images from television sets, projectors, and the like, into an endless variety of color abstracts. A plurality of light-collector channels conduct light from a color image to a translucent display screen, each channel diffusing and averaging light passing therethrough.

Abstract: A modular sign support is particularly adapted for supporting a real estate sign in the front yard area of a structure, as well as for supporting a name plate, electric lamp, mail box or the like in front of a private residence, business office or the like. The modular sign support includes a main vertical post or standard with a pointed bottom spike portion which is formed as a plurality of plastic modules, formed with socket and tenon connection, a top cross arm is similarly connected to the top of the post and includes at least one elongated arm portion with a pair of downwardly extending spaced apart tabs with holes therethrough to receive connector means to a display panel or sign.

Abstract: An improved display sign of the type in which interchangeable indicia can be mounted on both sides, and comprising a plurality of aluminum slats surrounded by an extruded aluminum frame. Each longitudinal edge of each slat is provided with a longitudinally extending hook to interlock with a similar hook on the next slat or, in the case of the top and bottom slats, with a projection integrally formed in a recess in the frame member. The slats are locked into the top and bottom frame members by means of a removable rod extending longitudinally thereof in a complementary shaped channel in the recess in the frame member.

Abstract: A firearm, especially of a type accommodating multiple caliber cartridges. In a preferred form, a revolver incorporates an axially revolvable barrel having plural bores of different caliber. The barrel is preferably selectively detachable and reversible top for bottom. A separately mounted means is provided for shell ejection. The revolving cylinder employed is provided with cartridge receiving bores of different caliber and is reversible end for end, being provided at opposite axial extremities mutually displaced sets of teeth accommodating appropriate cylinder rotation, this depending upon the caliber then selected. Means are provided for regulating different cylinder placements for the individual cylinder bores as to each set and as to the respective bores of each set. A safety feature is included for insuring that firing can occur only when proper cylinder and barrel registration exists.

Abstract: A fish bait positioner includes an off-center, weighted base having a flexible reed slideably mounted on the weighted base at one end of the flexible reed and a bait holder secured at the other end of the flexible reed.

Abstract: An apparatus for selectively lifting an animal trap to an above-the-ground disposition as an incident of an animal being caught in the trap. The apparatus includes structure defining a vertical slide, structure for disposing the slide to extend in an upright manner from the ground, a lift element slidably carried on the slide, structure for connecting the trap to the lift element, and structure responsive to an animal being trapped by the trap to rapidly slide the lift element from a preselected lower position on the slide to an upper position wherein the trap is disposed above the ground.

Abstract: The specification describes an aerodynamic structure having lift for use on an aerodyne. The structure comprises first and second essentially identical planar sections hingedly connected at their roots to one another at dihedral angles. The sections are moveable in unison to vary the angle between each section and its transverse axis.

Abstract: An amusement device having a toy wheeled vehicle and a trackway on which the vehicle moves. In the preferred embodiment, the wheeled vehicle has freely mounted wheels for rotation, and an upwardly extending rod which engages a lift mechanism flange. The lift mechanism raises the vehicle to a height at which gravitational force then imparts movement to the vehicle around a continuous trackway. The vehicle remains positioned on the trackway due to a trackway rail positioned between the freely mounted wheels of the vehicle. The trackway includes four different track sections which impart different movements to the vehicle as the vehicle moves along the trackway. In one track section, for example, the trackway imparts a loop-to-loop movement to the vehicle.

Abstract: A hand-held liquid herbicide applicator for wipingly applying the liquid herbicide on undesired vegetation. The applicator includes an elongated tubular handle having a supply container on its upper end with a special differential pressure operated vent valve in the container. A flow control valve is mounted in the handle for controlling the flow of the liquid herbicide through the handle to an applicator head carried on the bottom of the handle. The applicator head includes an especially configured synthetic sponge which is formed with a porous relatively dense peripheral skin so that the liquid herbicide received from the handle will evenly saturate the entire sponge to prevent uncontrollable liquid flow in one or more localized parts of the sponge.

Abstract: A fibrous web for planting seeds consists essentially of a mat of randomly oriented, unmodified, natural straw-like cellulosic fibers, viable seeds, water soluble adhesive and fertilizer. A method of sowing an area of soil with seeds comprising laying the aforementioned web over the area. Apparatus for producing the aforementioned web comprises a conveyor belt, means for driving the conveyor belt, means for depositing onto the conveyor belt while it is driven dry, fluffed randomly oriented, unmodified, natural cellulosic fibers to form a layer thereof on the conveyor belt, means for leveling the fluffed layer to form a mat, means for spraying an aqueous solution of water soluble adhesive onto the mat, means for depositing seed and fertilizer onto the wet adhesive bearing mat and means for drying the wet mat containing adhesive, seed and fertilizer.

Abstract: A rear side door structure for four-door type automobiles including a rear door panel having an upper hem which defines a lower edge of a window opening, a guide member extending upwardly from the upper hem of the door panel to divide the window opening into a front opening portion and rear opening portion, a front glass panel fitted to the front opening portion, a rear glass panel disposed in the rear opening portion for movement along the guide member. The guide member is inclined rearwardly so that the rear glass panel is shifted forwardly when it is moved downwardly. According to this arrangement, the rear glass panel can be retracted into the door panel without any interference with the cut-off portion which is normally provided in the door panel at the rear lower portion for avoiding the rear tire house.

Abstract: A domed support framework or truss comprises, as the roof form elements, wooden members oriented in the direction of doming and interconnected with one another so as to be tension-proof in such direction. The therebetween extending reinforcement ribs are likewise tension-proof wooden or timber elements. At their ends the roof form elements of the tension dome are frictionally connected with a tension element which extends in a polygon or catenary configuration between two supports to the same dome side and is guided over such supports in the compression dome. At that location the tension element is anchored at the extension of the compression dome. This construction compensates the horizontal thrust of the domed support framework, by virtue of the anchoring of the tension elements, without loading the roof form elements in the transverse direction, and thus, renders possible the use of materials which only can be loaded in one direction in tension, such as for instance wood.

Abstract: A wall module for use in constructing reinforced concrete buildings includes a plurality of spaced, thin walled tubes and a channel along the upper edge thereof within which concrete may be received to respectively form vertical and horizontal structural supports. A plurality of spaced, vertical support studs disposed on opposite sides of the tubes provide the module with sufficient compressive strength to carry the load of a floor mounted thereabove prior to filling the module with concrete. After the floor has been mounted on the wall modules, concrete is simultaneously poured into the tubes and channel of the module as well as into the space between the module and the floor to provide a continuous concrete connection between the floor and the wall of the resulting structure.

Abstract: A building structural unit and its method of construction is disclosed. Additionally provided is a method for the building of structural arrays with a plurality of the structural units. The structural unit of the present invention provides an inner structural core portion having provided attached to the outer surface thereof load-distributing surfaces. Suitable attachment means can be provided in order to facilitate connection of a plurality of the individual units together forming a structural array such as a wall, slab, ceiling, column, or the like. The structural units can be fastened together by means of tension members such as for example threaded rods, with each individual unit being provided with bores therethrough through which the tension members or rods can pass. Bolted or like connections at the tension member ends bear upon the provided load distributing surface to complete the desired mating of the individual units.

Abstract: Pipes for a telescopic mast have at least three guide grooves along their entire length, this is with the exception of the inner pipe having the smallest cross-sectional area which may not have guide grooves. All pipes except the pipe intended to be the outermost one in the telescopic mast have guide blocks attached to the lowermost portion of their outside. All pipes (4) except the pipe (4) intended to be the innermost one in the telescopic mast have guide blocks attached to the uppermost portion of their inside.

Abstract: A self-supporting steel tower for power supply lines at a voltage from 230 to 1000 KV is substantially a tri-dimensional truss structure having a trunk-of-pyramid shape with a triangular cross-section, in particular in the form of an isosceles right triangle. The tower side corresponding to the hypotenuse of the triangle is directed vertically and the other two sides corresponding to the cathetuses are slightly sloping, whereby the tower is tapered upward.

Abstract: A container capping apparatus having a generally vertical tubular spindle carrying a cap holding chuck assembly is rotatable about its axis to apply a screw cap to a container with predetermined force. A control rod is vertically movable within the spindle against an actuator spring to release the applied cap from the chuck. An axle carried by the control rod projects through vertically elongated slots in opposite sides of the spindle, and is received in a control collar slidable on the spindle. A cam follower is carried by a yoke vertically slidable on the spindle and an external adjusting nut is carried by the yoke for movement therewith in operative engagement with the collar. The vertical position of the nut relative to the yoke is selectively adjustable, thereby to adjust the position of the control rod relative to the cam follower.

Abstract: This invention relates to method and apparatus for producing a composite container having a body label or tubular sleeve mounted temporarily thereon adapted to be shrunken into final surface covering position. The tubular sleeve is preformed of thin flexible plastic material and flat-folded until ready for use when it is fully opened and arcuately conveyed in axial registry with a container therebeneath. The sleeve preform of heat-shrinkable plastic material is telescopically assembled onto the container while the latter is conveyed through a coincidental arcuate path. The container preferably consists of a one or two-component lightweight hollow plastic container with the tubular preform made slightly larger in diameter to surround a body portion of the container.

Abstract: A rotary lawn mower cutter member in the form of a ring supporting a plurality of grass cutters each in the form of an helical torsion spring having a leg projecting beyond the periphery of the ring. The helical springs are mounted in holders removably attached to the ring such that, upon striking an obstacle, the spring projecting leg is yieldably deflected. The ring is connected to a hub by spokes and the hub is mounted on the end of the power output shaft of a rotary lawn mower.

Abstract: A power actuated picking head is mounted on the upper end of an elongated handle which is hand manipulated from ground level to pick tree borne olives or similar fruits. The picking head has a built-in collection hopper with an open top having ledges around its rim, and, a bottom discharge opening connected to a ground level receptacle by a cloth conduit for gravity guidance of the picked fruit without damage. A power rotated rake-like member, with right angularly hooked tines, rakes the fruit into the hopper, in cooperation with the ledges, while passing leaves and barring branches. A compartment in the head contains a motor, powered by flexible conduit from ground level.

Abstract: The ring mount is of a two-piece construction and includes a hard plastic mounting support fixed in an annular opening in the ring rail. An annular recess is provided in the upper inner portion of the mounting support. A soft plastic insert is adapted to closely fit within the annular recess of the mounting support and is provided with an annular groove in the inner surface which is adapted to receive and support the lower flange of the ring. The two-piece ring mount is positioned between the metallic ring rail and the metallic ring and provides noise and vibration dampening means for resiliently supporting the metallic ring on the ring rail.

Abstract: A deflector for twisting double twisting spindles with pneumatic threading of the filament and with prepositioning of the rotating part of the spindle during the threading phase. Substantially between the circumference described by the wall containing the outlet port of the filament of the rotating part and the peripheral rim of the rotating plate is arranged at least temporarily an angular deflector in cooperation with the neighborhood of the radial plane in which is disposed the outlet of the filament in the rotating part cooperating through its extension with the neighborhood of the tangent to the curved rim of the rotating plate.

Abstract: For automatic feeding of slivers through drawing rollers there is provided a sliver-processing frame having drawing rollers, tubes for conveying slivers to be drawn and a plurality of suction elements connected to a common source of low pressure wherein the drawing rollers are enclosed in a casing of which the interior is connected to the source of low pressure the casing having inlet orifices for admitting cleaning air to the surfaces of the drawing rollers, one end of each tube leading into the casing.

Abstract: The present invention relates to a rotary-reactive internal combustion engine in which the reactive powers of the exhaust gas add to the driving torque of the present engine. The classification of this engine: The kind of the fuel is a liquid fuel. One cycle consists of the three working periods. The ignition of the fuel realizes inside the four combustion chambers by the high-tension ignition. One cycle is corresponding to a 360.degree. turning angle of the shaft of the rotor. The method of the formation of the mixture is the external mixing or is the pump fuel-air mixture with a very high pressure feed. The constructional distinctness is the rotary engine. The method of the formation of the power is the reactive power. The process of the scavenging is through forced scavenging. The present engine will be able to create the power and will work with a high speed rotation. This engine system allows it to use both synthetic fuel and common gasoline.

Abstract: A multi-burn restartable solid rocket fuel having plural layers, each independently ignitable, including a central core, and at least one outer cylindrical layer separated from the central core by a non-ignitable layer, and the method of utilization therefor including first igniting the central core in an end burned configuration, and subsequently or concurrently igniting the next adjacent layer or layers in an end burned configuration, as desired.

Abstract: A mixed flow, high bypass, gas turbofan engine that is small and compact, and that develops a thrust in the range of approximately 200-300 pounds. The engine has an axial length of approximately 18 inches, an air inlet of approximately 10 inches in diameter, and an exhaust nozzle of approximately 6 inches in diameter. To reduce engine length high pressure compressor diameter, a high pressure compressor is positioned in a location that is displaced from and is preferably parallel to the engine axis (i.e., centerline), a burner (i.e., combustion chamber) is similarly positioned on the other side of the engine axis, only one turbine is used, and a unique flow path also is used. In addition, a heat exchanger of the regenerative type which includes a plurality of pipe diffusers is used, and it is positioned in the hot exhaust flow of the single turbine to pre-heat the compressor air prior to entry into the burner. Further, a gear shift may be used with the compressor to give better part-power performance.

Abstract: A hydrocentrifugal machine is disclosed in which the rotor is a vortex-expeller rotor defining two generally spiral-shaped vortex-expeller passages and a hydraulic induction coil comprising a helical, inwardly-opening channel is affixed to the inner face of the outer, cylindrical wall of the centrifugation chamber.

Abstract: Discussed herein is a rapid actuating device for a hydraulic actuator utilizing two or more relief valves to control the hydraulic flow of the actuator for various loading or no loading conditions in order to speed up the required operation time.

Abstract: A hot-gas reciprocating machine comprises two intercommunicating spaces of variable volume and two pistons (1 and 11) for varying the volumes of these spaces. The two pistons are coupled to two parallel crank shafts (16 and 17) and are movable with an adjustable phase difference. For balancing the engine a system of counterweights is provided comprising a counterweight (30, 31) on each crank shaft and a counterweight (32, 33) on each of two auxiliary shafts (26, 28) which are coupled one to each crank shaft for rotation therewith at the same speed as and in the opposite direction, each auxiliary shaft extending parallel with the associated crank shaft on the side thereof remote from the other crank shaft.

Abstract: A rotary external combustion heat engine for furnishing mechanical energy from a source of heat. The engine includes a ring-like stator having an oval rotor chamber enclosing a cylindrical rotor eccentrically placed within the chamber to define a high displacement high temperature fluid chamber and a lower displacement low temperature fluid chamber. A plurality of extensible vanes extend outwardly from the rotor in sliding contact with the inner surface of the rotor chamber. A source of heat supplies thermal energy to fluid supplied to the high temperature chamber, while a heat sink cools fluid supplied to the low temperature chamber. An economizer heat exchanger is also provided for preheating the working fluid. The relative position of the rotor within the rotor chamber is adjustable for varying the relative displacement of the fluid chambers to control engine working parameters.

Abstract: A process for removing carbon dioxide in geothermal power generating processes employing a geothermal fluid such as geothermal brine containing carbon dioxide, to improve the efficiency of geothermal power generation, comprises introducing an aqueous alkaline solution, preferably an aqueous calcium hydroxide solution, into a vapor stream obtained from the brine during power generation, to remove carbon dioxide from the stream. In the case, for example, of power generation by direct contact heat exchange between geothermal brine and a working fluid such as isobutane, where the working fluid is expanded to generate power, aqueous calcium hydroxide can be introduced into a direct contact condenser into contact with the working fluid therein to remove CO.sub.2 present in the working fluid, thereby aiding in reducing loss of working fluid from the system and aiding in reducing pump power. The aqueous alkaline, e.g.

Abstract: Process for recovery of energy from geothermal fluids such as geothermal brine in a geothermal formation by injecting a water immiscible working fluid, preferably organic, typically a hydrocarbon, e.g. isobutane, into the geothermal formation containing a geothermal fluid such as hot brine, wherein the hydrocarbon working fluid is heated by direct heat exchange contact with the hot geothermal fluid in the formation, and employing the hot working fluid to drive a heat engine or turbine to produce work or electrical energy or to provide heat energy to a chemical process (e.g., alcohol manufacture). The cooled working fluid discharged from the turbine is reinjected into the geothermal formation. The working fluid preferably has a density which changes substantially with temperature to provide a substantial pressure difference for causing flow of heated working fluid up the production well. The density difference can be due to phase transfer from liquid to gas.

Abstract: A control system for a steam turbine operated with a steam bypass system. In the control system, bypass valve control is according to setpoints generated as a function of a combined flow reference (CFR) signal. The CFR signal is representative of boiler outlet flow under all turbine operating phases and is generated by multiplying the sum of the steam admission control valve flow demand and the high pressure bypass flow demand by boiler pressure. An actual load demand (ALD) signal indicative of the turbine demand for steam is produced from the product of the steam admission control valve flow demand and boiler pressure, and is used for intercept valve control. Excessive steam flow in the lower pressure bypass subsystem is prevented by providing an override for the normal control to prevent high heat impact to the condenser and latter stages of the turbine high pressure section.

Abstract: There is disclosed a thermoelectric device powered by a direct current power supply in which the circuitry comprises an integrated timer circuit and a two-stage, feed-back amplifier which, when switched in, produces a digital direct current pulse for delivery to the thermoelectric device. An LED circuit is included to show when the integrated timer circuit is operating to deliver the desired current to the thermoelectric device.

Abstract: A flash subcooler is provided to meter a portion of the refrigerant flowing from the condenser to the evaporator to an intermediate heat exchanger to subcool refrigerant flowing from the condenser to the evaporator. This diverted refrigerant is flashed to provide subcooling and is then redirected to the compressor as is the flow of refrigerant from the evaporator. Both the refrigeration system and subassemblies for accomplishing the above are disclosed as well as methods of operation thereof.

Abstract: This invention is directed to a variable air volume cooling system for a building which utilized changes in the diameter of the belt going around a two piece driver pulley and a follower two piece driven pulley to effect changes in fan speed and, accordingly, the air volume supplied. A control means to operate a servo-motor connected to the driver pulley provides for separating the two piece driven pulley to slow the fan, driving the two pieces of the driven pulley together to speed up the fan, and for maintaining the same speed should a desired temperature range be obtained. The control compares the temperature of the area to be cooled with the speed of the fan to produce its outputs. Deadband operation is provided to eliminate toggling and other excesses of output reversals.