Abstract: A laminated container structure in which a peelable coupon or the like forms an integral portion of the outer ply of the container wall and is defined by a perforated tear outline. In one embodiment, a release agent is coated on the back of the coupon area to prevent adherence of the coupon to the adhesive joining together the outer and inner plies of the container. In another embodiment, the inner ply is formed of cylinderboard adhesively fastened to the outer ply, the perforate coupon tear outline extending through the outer ply, adhesive and outermost layer of the inner ply so that peeling of the coupon will not remove the inner layers of the inner ply and thus not destroy the integrity of the container.

Abstract: An arrangement for providing a pocket sheet (10) having inserts (42) located in pockets of the pocket sheet with information placed on the inserts exposed. The arrangement involves providing an insert sheet (34) having substantially the same length and width as the pocket sheet, the insert sheet having a plurality of inserts (42) on which the information may be placed, after which the inserts may be separated from each other and placed in the pockets.

Abstract: A day-night picture achieves a realistic reproduction of the twinkling of distant city lights or the like, by backlighting small apertures in the picture with a fine, randomly moving reflection pattern obtained by suspending pieces of crumpled reflective foil from fine threads behind the picture above a light source whose heat creates convection currents which slowly move the foil pieces in a random manner.

Abstract: Spring loaded devices for spacing index strips and other components of a visible index with respect to a frame supporting those components and for removably attaching items to or holding them against the frame.

Abstract: A mechanism to fire a double barrel shotgun, and so arranged to fire each barrel alternately in perfect sequence, starting with either barrel and by a simple adjustment to fire either barrel continuously with a single outside two piece hammer and a single trigger, the said hammer hinged to provide a limited lateral movement to the front face of the hammer with sufficient lateral range to be easily directed to the right barrel or the left barrel as determined by the selector cam.

Abstract: A gun rest for firearms which is characterized by a monopod having a base cylinder and a plurality of nesting, tapered interior tubes or cylinders, each having a successively smaller diameter and arranged in concentric, normally retracted, telescoping configuration inside the base cylinder. A mount plate is provided with a pivot clamp at one end for pivotal cooperation with the base cylinder, and a monopod clamp at the opposite end for removably securing the opposite end of the base cylinder to the plate. The mount plate is further provided with a pair of upwardly extending barrel clamps mounted in spaced relationship on opposite sides of the plate from the pivot clamp and the monopod clamp, respectively, for removable attachment of the monopod and mount plate to the barrel of a gun or rifle. When not in use the monopod is positioned in essentially parallel, retracted relationship to and beneath the mount plate and the barrel of the firearm.

Abstract: An elongated tubular body portion of the fishing lure is provided to define a through passageway for a continuous flow of water when the fishing lure is being trolled behind a boat or being retrieved as by a rod and reel, or in any manner is caused to move lengthwisely through the water. A pair of longitudinally extending fish hooks extend outwardly from a rear end portion of the tubular body and a pair of through holes are provided in the tubular body, the pairs of fish hooks and holes preferably being in a diametrically opposed aligned relation. An elastic member diametrically spans the tubular body and extends outwardly through the holes, engaging the outer surfaces of the tubular body portion in proximity to the through holes.

Abstract: An amusement device of the present invention comprises a bank constructed in the form of a plush doll having a coin insert aperture in the facial area, such as the mouth, leading to an internal coin receptacle. A pawl and ratchet mechanism is disposed within the doll to prevent coins inserted in the doll from completely entering the coin receptacle until the pawl and ratchet mechanism is manually activated by pushing or squeezing a predetermined area of the doll, thereby rotating a ratchet wheel to force the coins into the coin receptacle and simultaneously causing pivotal movement of a face distorting member so that it appears as if the doll is chewing the coin.

Abstract: A glider formed from a multi-sided tube open at its ends is disclosed. The body and lifting surfaces of the glider comprise a multi-sided tube including a top wall of planar configuration; a pair of opposed upper side walls of planar configuration integral with the top wall extending downward and outward a distance; a pair of opposed vertical side walls of planar configuration integral with the upper side walls; a pair of opposed lower side walls of planar configuration integral with the side walls extending downward and inward to a point inward of a vertical extension of the top wall and upper side wall intersections; a bottom wall extending between lower end walls and integral therewith enclosing the structure. The bottom wall includes a pair of upward extending planar sections meeting at a midpoint between lower end walls to form a ridge.

Abstract: A toy vehicle and a launcher includes an integral latch mechanism for holding the vehicle in a biased position and an actuating member for selectively releasing the latch. The vehicle includes an elongated tube of substantially dense, rigid material defining a frame to which wheels may be secured. The tube is encased within a soft, resilient, open cell foam material such as polyurethane foam which has been molded in the form of a vehicle body. A resilient, biasing member is mounted within the tube and is held in a compressed state by the latch. The launching member includes connection means to permit the connection of a series of launching members.

Abstract: The invention relates to a method of producing plants mycorrhyzated (i.e. having their roots associated) with symbiotic fungi, so as to apply mycorrhyzation to already adult plants and obtain mycorrhyzated plants which can produce fruit-bearing bodies immediately after being planted.The method consists in cultivating a set of young plants in sterile soil, preferably starting from seed, and in mycorrhyzating the young plants grown in sterile conditions, by placing their roots in contact with roots previously mycorrhyzated with the desired fungus and obtained under natural conditions from other plants. The resulting pilot young plants are planted in a sterile greenhouse or sterile nursery, in which already adult plants are subsequently planted so as to be mycorrhyzated, after secondary roots have first been eliminated and the remaining roots have been sterilized. The pilot young plants mycorrhyzate the adult plants with the desired fungus, so that the plants can immediately produce fruit-bearing bodies.

Abstract: This invention relates to the art of certain new and useful improvements in means and methods for shrub and tree surgery, and more particularly to a use of fiberglass and fiberglass resin and hardener techniques to more effectively treat tree wounds and cavities. Such methods and means have been found more successful than other tree surgery methods now in use, i.e., the use of concrete filler, sheet metal plates, etc. for permanent tree healing and for insect and element protection.Two procedures are used, dictated by the type of injury, (1) a combination of fiberglass resin and hardener can be applied directly to damaged exposed wood tissue (where branches up to 12 inches in diameter have just been removed, or other exposed tissue areas such as trunks, roots, pruned limb ends, etc.

Abstract: Disclosed is an improved method of inducing lightwood formation in a living conifer. The improved method comprises heating the sapwood of a selected section of a conifer to a temperature of from about 40.degree. C. to about 100.degree. C. by means of an energy source such as radiant energy.

Abstract: A bleacher structure for spectators comprising a system of interconnected upright posts, cross beams, and diagonal stiffening members with channel beam seats and channel beam footrests locked into the structure by means of hook members on the channel beams cooperating with slots in the upright posts and the cross beams.

Abstract: A multi-unit dwelling having individual living units therein which have main living areas protected from noise and visual pollution and which are arranged to afford maximum privacy to each living unit. The multi-unit dwelling includes a plurality of contiguous living units arranged to form a courtyard enclosed on at least three sides there between which is protected from noise and visual pollution by the plurality living units. Each of the living units includes a court side exposed to said courtyard and a service side exposed to vehicle access and the associated noise and visual pollution associated with vehicles. Each living unit includes a living area and a bedroom area disposed on the court side of the living unit and a bathroom, a utility room, storage areas, a garage, and a main private entrance way disposed on said service side of said living unit.

Abstract: A building structure for use in row housing developments includes a plurality of individual dwellings, which, when viewed from above, define substantially equilateral triangles, the corners of which are truncated, the base of each triangular dwelling forming the front of the dwelling and opposing the base of each adjacent triangular dwelling.

Abstract: An improved stud wall structure comprising a folded T-shaped windstrip brace member installed in a saw kerf extending diagonally across the structure for substantially eliminate racking. The T-shaped brace member has a double layer top member portion and a pair of spaced apart flanges extending substantially perpendicularly from said top member portion. The flanges are unconnected at their respective outwardly extending edges, and fasteners such as nails driven through the brace member wedge the unconnected flanges against the sides of the saw kerf to hold the brace member in place on the structure.

Abstract: A method for erecting the supporting wall of a domed structure is disclosed in which a peripheral foundation for the wall is formed conforming in plan generally to the periphery of the structure and has hollow box columns positioned thereon at predetermined points. The lower ends of the columns are secured to the foundation at a plurality of points with temporary moment connections for the purpose of resisting load moments during the erection procedure. Wall panels are secured to the columns to close the sides of the structure and a supporting ring formed of a plurality of pre-cast segments is secured to the top of the columns. After the ring is completed and supported the temporary moment connections at the lower ends of the columns are released to leave only pin connections at the column bases whereby the entire wall structure acts as a complete structural unit. The dome, typically an air-supported fabric dome, is erected on the ring with its structural elements, namely cables, secured to the ring.

Abstract: In an apparatus for closing about the mouth of a filled sausage casing a closure clip 8 having two legs, the apparatus including a plate 1 provided with a clip guideway 6,7, means on the plate for gathering the casing 2,3, a closure die 17, a punch 9 for advancing a clip through the guideway about the gathered casing and against the die to cause the clip to be closed about the casing, and means 16 for introducing a loop 15 of flexible material so that the loop is locked to the sausage casing by the closure of the clip, whereby the sausage may be hung by the loop, the improvement wherein said loop introducing means comprises means for forming loops from a length of flexible material, and holder means 14 for successively engaging each loop and operatively associated with the punch so as to advance the loop as the punch and clip advance and to bring the loop into such position intercepting the guideway that one leg of the clip passes through the loop, whereupon the holder means is retracted and the clip proceeds

Abstract: Apparatus is provided for automatically applying and heat-sealing a lid of thermoplastic film to the top of a cup. The film is supplied in a roll and the leading end is fed into a position between the top of the cup and a heat-sealing head. When the apparatus is run through an operating cycle, the cup and the head are brought together to seal a section of film to the rim of the cup and sever the section from the roll. The head is characterized by an annular heated cushion and a slitting device to from a slit in the center of the lid which enhances the seal, particularly if the cup contains a hot liquid. In an alternative arrangement, the slitting mechanism is located along the path of the film and the center of the head is constructed to prevent exposing the center of the lid to high temperature.

Abstract: A continuous system and apparatus for applying a rectangular lid with depending flanges to a rectangular box by continuously passing a series of spaced open top boxes through a lidding station beneath a stack of lids directly above the lidding station, dropping the bottom lid from the stack into position to be picked up by the box as it passes through the lidding station.

Abstract: A process for setting in a desired shape a product at least a portion of which comprises electrostatically spun fibres is disclosed. The process comprises maintaining the product in the desired shape at a temperature below the melding temperature of the electrostatically spun fibres. The desired shape may be the as-spun shape of the product or a shape obtained by deformation of the product, i.e. the product is reshaped. The fibres preferably comprise a polyurethane and reshaping is preferably effected on a former. The reshaped product may be employed as a vascular prosthesis.

Abstract: In accordance with the present invention protective envelopes for suction tubes or drinking straws as well as the tapes joining them are manufactured at the same time and of the same material. The suction tubes are placed with equal intervals transversely between two thermoplastic webs, whereupon these webs are sealed to each other around the suction tubes. At the same time the webs are punched or cut so that individual suction tube envelopes are obtained which are mutually connected by means of straps extending between the envelopes. In this manner all handling of separate wrapped suction tubes is avoided, so that the suction tube band can be manufactured with appreciably greater precision. The invention relates to the method of manufacture as well as to a machine for its realization and the finished suction tube band.

Abstract: A vacuum grass collecting apparatus for a tractor-type lawnmower having a rear discharge opening in its cutting deck and a rear power-take-off. A refuse container and a blower are independently mounted on the rear of a tractor-type lawnmower. The blower consists essentially of a housing having an intake opening and a discharge opening, a rotatable drive shaft having a plurality of impeller blades mounted thereon and a support bearing for the rotatable drive shaft. An articulated duct is positioned under the rear axle of the tractor-type lawnmower and interconnects the rear discharge opening in the cutting deck and the intake opening in the housing of the blower. Another duct interconnects the discharge opening in the housing of the blower and an intake opening in the refuse container. The entire apparatus is positioned between the two imaginary parallel vertical planes which contain the outer extremities of the tractor-type lawnmower.

Abstract: A forage harvester, otherwise of generally typical construction, is modified to include kernel-processing means in the form of a pair of cooperative compressor rolls situated in close proximity to the cutterhead and adapted to receive from the cutterhead fragmented crops and to further reduce the crops and especially to crack the kernels. The compressor rolls are of the type usually employed in a roller mill and have corrugated cylindrical outer surfaces particularly adapted to crack the kernels.

Abstract: A rotary lawn mower is provided with a grass collection bag arrangement comprising a bag holder having a flexible skirt for supporting a disposable collection bag. The bag holder is mountable on a mounting plate facing rearwardly on the mower housing and close coupled to a grass discharge chute formed on the housing. The bag holder is retained on the mounting plate by a pivotally mounted lever engagable with the bag holder frame and operable in the release position to actuate an ignition grounding switch to ground the ignition system of the mower engine. The mower engine power takeoff shaft is coupled to a rotary blade which is mounted on a hub having a cylindrical brake drum fixed thereto. A spring coil brake band is disposed around the brake drum and pivotally mounted at one end to the mower housing and connected at the opposite end to a flexible cable which is connected to the bag holder retaining lever.

Abstract: A reel blade mower that provides for proper reel blade contact pressure on the bed knife at all times without any system adjustment. The mower includes a free floating reel blade suspended on a pair of pivotal support arms that is not mechanically fixed to a rigid position, but that is free to move vertically relative to the bed knife. The overall force of the reel blade in contact with the bed knife (contact pressure) is determined by combining the downward vector from the weight of the blade system and the force vector generated by the rotary movement of the reel blades. The mower is not damaged by debris engaging the reel blade or bed knife which easily passes through.

Abstract: In a mowing implement comprising a housing and a number of cutting members rotatably journalled on said housing the danger of damage of the implement due to stones jammed between a cutting member and said housing is avoided in that each cutter is fastened to the top side of a holder skimming the top side of the housing.

Abstract: A machine (10) for forming material into cylindrical bales of density increasing from the center to the periphery, comprising a mobile structure (11) including first (14) and second (15) body portions pivotably secured together on a generally horizontal transverse axis, a baling chamber (20), in the structure, defined by portions of the peripheries of a plurality of closely spaced conveyors in the form right circular cylinders (21-39) mounted with their axes parallel and passing through points lying on a smooth closed curve in a vertical plane perpendicular to the axis, the lower half of the curve being generally a circular arc and the upper half departing outwardly from circularity by an amount which varies smoothly to and from a maximum in the vertical direction: a pickup mechanism (80-83) is provided for gathering material to be baled from the ground and introducing it as a ribbon peripherally into the chamber at its bottom, and a drive arrangement (17, 60-67, 70-73, 84, 85) is provided for causing operati

Abstract: A hay-gathering machine for pulling windrows of hay, turning the hay over, and scattering it, having a rake-wheel comprising a plurality of tine-carriers radially directed outwards from an almost vertically-pointed swivel pin, wherein the tine-carriers at their outer ends are provided with rake-tines. At the end of each tine-carrier, which is directed toward the swivel pin of the rake-wheel, there is attached at least one control lever, which, for the pulling of windrows, is connected with a first open control channel in a tensional or a form-locking, or in a purely form-locking manner. The tensional or form-locking connection of the control lever with the first open control channel is made by means of a spring or the like, while the purely form-locking engagement of the control lever into the first control channel is made by means of cooperation of the roller on the control lever with a guide way which is parallel to the first control channel.

Abstract: An improved yarn reserve disc having an annular rim of a radial length of at least 7 mm extending radially outwardly from a lower portion of an outer, circumferential, yarn storage surface thereon in a spindle assembly of a two-for-one twister textile yarn processing machine. The annular rim prevents coils of yarn wrapped around such yarn reserve disc, upon breakage of the yarn during processing by the spindle assembly, from slipping down off of the yarn storage disc to interfere with subsequent driving of the spindle assembly.

Abstract: An effect yarn and process for manufacture thereof is disclosed when the effect comprises a slub that is formed after the yarn leaves the yarn package during later knitting or weaving operations. The effect yarn is particularly useful since it processes through such operations similar to conventional air-plied yarns.

Abstract: A bulky textured multifilament yarn comprises sections of interlaced individual filaments and sections of non-interlaced individual filaments, wherein the interlaced and non-interlaced sections are formed alternately along the lengthwise direction of the yarn, the filaments in any predetermined length of the yarn are substantially identical in length, and some portions of the individual filaments protrude out from the axis of the yarn. The yarn is made by slackening a multifilament yarn treated by a false twisting operation, and then by interlacing the slackened multifilament yarn by means of a fluid jet stream while taking up the multifilament yarn.

Abstract: A device for burning fuel with air is provided with means for causing partly recirculation of the combustion gases prior to their exit via a preheater. The degree of recirculation may be governed by a parallel path having controllable flow resistance and in which no recirculation occurs.

Abstract: A solid propellant rocket motor of gas generator of the type having retractable filaments embedded in the propellant for the purpose of controlling the overall thrust or mass flow output is combined with a channeled separator located between the propellant and its casing with the channels open to the combustion chamber. This results in distribution of combustion chamber pressure and temperatures over the exterior of the propellant grain so that distortion of the grain will not occur sufficiently to cause binding or sticking of the filament in their holes in the propellant nor will the holes be enlarged to cause uncontrolled burning between the filament and the hole.

Abstract: A vehicle emissions control system includes an air pump (12), a catalytic converter (22) communicated to the air pump, and a bleed control valve (28) which controls the quantity of air communicated from the air pump to the catalytic converter. The bleed valve includes a support arm (50) which suspends a valve element (40) adjacent a tapered valve surface (36). The support arm relaxes in response to repeated flexing due to the pulsating output of the air pump. Accordingly, when the vehicle is new, the valve element is held away from the valve seat to permit substantially uninhibited communication through the bleed valve so that almost all of the air which would otherwise be communicated to the catalytic converter is bled off.

Abstract: A soot treatment device for a Diesel engine comprises a soot collector arranged in an exhaust gas system including a cyclone, wire nets and an atomizer for spraying engine oil into exhaust gases passing through the soot collector, an oil supply circuit for supplying the engine oil to the soot collector, an oil feed circuit for feeding the engine oil containing soot collected in the soot collector to a fuel system of the engine and control means for actuating these circuits at determined timing, thereby again burning the collected soot together with fuel in the engine.

Abstract: Disclosed is a vehicle exhaust system containing a three-way catalytic converter. An insulated flexible duct connects the outlet of the engine exhaust manifold with the inlet of the three-way catalytic converter to retain the exhaust engine gases at a temperature greater than the ignition temperature of the three-way catalyst in the catalytic converter. The insulated flexible duct is preferably made of an inner flexible metal conduit surrounded by fibrous insulation which in turn is surrounded on the outside by a second flexible metal conduit. The system is economical, contains no active elements which would require maintenance or could get out of order, is adaptable to motor vehicles of all types (especially automobiles, light trucks and vans) including those powered by either gasoline and diesel engines and entirely eliminates the need for expensive and complicated light-off catalysts in the system.

Abstract: Heat-resistant filters 6, 7 are disposed at the upstream side of a catalyst bed 9. These heat-resistant filters 6, 7 perform filtration to completely catch and remove the smoke particles suspended by the exhaust gas, so that the undesirable attaching of the smoke particles to the catalyst bed 9 is fairly avoided. Also, means are provided to regenerate the heat-resistant filters simply by burning the smoke particles attaching to these filters. In another embodiment, a heat-resistant filter 24 and a catalyst bed 26 are shaped to have hollow cylindrical forms and are superposed to each other. For regenerating the heat-resistant filter 24, hot air is introduced into the filter 24 by the action of a high pressure burner 28 or a vacuum generating section 33. The heat-resistant filter 24 and the catalyst bed 26 are accomodated by a single case 21.

Abstract: An exhaust gas purifying system for an automobile engine including at least first and second engine cylinder has a shutter valve for interrupting the supply of a combustible air-fuel mixture to the first engine cylinder during a particular engine operating condition, a three-way electromagnetically operated valve for controlling the operation of the shutter valve, and a secondary air supply unit including a switching valve for selectively supplying a secondary air to a portion of an exhaust passage upstream of at least one catalyst unit disposed in the exhaust passage.

Abstract: Trapped air method of generating turbine or rotary power within a deepsea environment. Rotary turbine power is generated by admitting water through a submerged turbine and into a trapped air sphere, so as to compress the trapped air. As the sphere fills with water, the compressed air assists in bleeding of the admitted water from the sphere via a flexible conduit extending to a point above the sea surface.

Abstract: A device for converting the energy of sea and ocean waves, including a turbogenerator connected by means of pipelines to input and output elements on which there are mounted ballast systems and stabilizers. The input and output elements are designed as a high pressure vessel and a low pressure vessel, respectively, each having a gas cushion. A high pressure compressor unit and a low pressure compressor unit are, respectively, mounted on these vessels and are connected to high pressure and low pressure gas tanks, respectively, and to the respective gas cushions. The converter is connected at at least two different points to the sea bottom by means of at least two flexible cords the length of at least one of which may be altered.

Abstract: A hydraulic system comprising a pair of actuators operable to move a single load, each of which has a fluid inlet, a variable displacement pump including means responsive to a pressure for varying the displacement of the pump, a pilot operated meter-in valve associated with each actuator for supplying fluid from the pump to its respective actuator, and means for sensing the pressures between each meter-in valve and its associated actuator and applying an average of said pressures to said responsive means of said pump.

Abstract: Conditional exchanging of working fluid between plural fluid circuits (13A, 13B) having separate supply pumps (18A, 18B) is provided for without continuously bleeding fluid from the pump control pressure lines (21A, 21B). Each circuit (13A, 13B) has a pump control (19A, 19B) responsive to a control pressure, a plurality of fluid motors (14A, 15A, 16A, 14B, 15B, 16B), and a group of resolver valves (38A, 38B) which compare motor pressures and intercommunicate the pump control (19A, 19B) with the most highly pressurized motor (14A, 15A, 16A, 14B, 15B, 16B). At times when fluid from one circuit (13A, 13B) is being delivered to a motor (16A, 16B) of another circuit (13A, 13B), the pressure comparing function of the resolver group (38A, 38B) of the one circuit (13A, 13 B) is extended to include the motor (16A, 16B) of the other circuit (13A, 13B). Among other uses, the system (11) may be used on excavator vehicles having plural fluid motors performing a variety of different functions.

Abstract: A free-piston Stirling engine usable as a heat pump has a closed vessel filled with helium working gas which is heated at the bottom end and cooled at the top end. The vessel contains a displacer supported for axial reciprocal oscillation on a gas spring post mounted on the vessel. The displacer shuttles the working gas from end to end in the vessel, alternately heating and cooling the gas. The vessel is sealed with a flexible diaphragm which flexes in response to the pressure wave generated in the vessel as the working gas is alternately heated and cooled. When the diaphragm flexes, it displaces hydraulic fluid in a hydraulic chamber and drives a power piston for driving a linear alternator and a gas compressor. A gas spring operating on a second hydraulic cylinder on the other side of the power piston stores part of the energy of the piston stroke and returns it for the return stroke.

Abstract: In a power plant, a deaerator is a feedwater conditioning device which provides direct contact feedwater heating as well as providing for oxygen removal to inhibit corrosion. Under some conditions, called transients, rapid depressurization could occur in the deaerator which might result in damage to internal deaerator parts. By limiting the condensate flow into the deaerator, the rate of depressurization can be reduced. A control system is described which will react to a reduction in turbine load by reducing the flow of condensate to the deaerator.

Abstract: The invention resides in a method of producing artificial snow directly from ice, for ski slopes. Ice is formed on a surface exposed to an ambient temperature at or below the freezing temperature of water by flowing water onto the surface. The rate of water deposition is controlled such that all of the water deposited on the surface freezer before additional water is deposited thereon. The ice is then comminuted into snow-like particles and distributed onto the slope.

Abstract: A refrigeration system employing an adiabatic expansion and an impulse generating means for the oscillatory compression and pumping of the working fluid. The impulse generating means is a venturi having a liquid inlet downstream of the throat with means for applying heat by a heat source, typically the waste heat of an automobile engine to the working fluid. The working fluid may be used to cool air through an evaporation in an automobile passenger compartment.

Abstract: The invention relates to defroster control apparatus for the evaporator of a refrigerator. A frost sensor for measuring temperature is mounted a predetermined distance from a surface of the evaporator which corresponds to the permissible thickness of frost layer. Control apparatus including a comparator circuit initiates defrosting when the frost sensor temperature falls below a reference temperature. In this construction the frost layer grows in the direction of the frost sensor which is swept by the surrounding air. During each operating cycle the frost sensor initially measures a temperature approximating to the surrounding temperature. As the frost progressively increases, this temperature falls because the air circulation in the vicinity of the frost sensor is progressively more influenced as the thickness of the frost layer increases. In the extreme case, the frost sensor can come into contact with the frost layer.

Abstract: A control system for controlling the operation of a reciprocating resonant free-piston variable stroke compressor of the type driven by electrodynamic linear motors wherein the spring-mass system of the compressor which is forced into vibration by the linear motor, is arranged to have a selectively variable mechanical resonant frequency generally centered on the power line frequency of the alternating current power source used to drive the linear motor. The control system provided by this invention variably controls the opening and closing of a gas spring control valve that in turn regulates the pressure of gas filled volumes selectively connected to a manifold vented by the valve. The volumes comprise the resilient gas springs for the resonant piston compressor.