Abstract: A flail for a rotary vegetation cutter. The flail is attached to a rotor and is centrifugally swung around the axis of rotation of the rotor to strike vegetation such as grass and weeds to cut them down. The flail comprises a plurality of metal filaments braided into an elongated strand and an abradable jacket surrounding and embracing the strand. When rotated the flail strikes and cuts objects in its path, the jacekt near its free end abrading away to expose the filaments adjacent to the free end. The strand unravels where the jacket has been removed to form a group of loose metallic filament ends.

Abstract: The invention is concerned with establishing the datum level of a lance or cartridge relative to the surface of a bath of molten metal in a metallurgical vessel. A voltage is applied to the movable lance or cartridge in such manner that contact of the lance or cartridge with the bath surface causes an earth leakage current to be established. Electrical circuitry is incorporated to open a circuit breaker upon flow of a predetermined earth leakage current and actuate an indication on a distance measuring device coupled to the movable lance or cartridge.

Abstract: A strain gauge pick-up for the measurement of a test piece. This pick-up ludes two tapping points mounted on a pair of rigid elbow members. The elbow members are spaced a predetermined distance apart, and their spacing varies as the tapping points are applied to the test piece. The elbow members are attached to the deflection plate which flexes as the spacing between the elbow members changes. A wire strain gauge is positioned on the deflection plate and senses the flexing motion. Several pick-ups can be integrated so that their tapping points are substantially colinear.

Abstract: An acoustic micrometer for measuring the exact distance between two electrically interconnected metallic objects is disclosed. The micrometer comprises a micrometer head having an electrical contact at one end adapted to engage one of the metallic objects when taking a measurement, a housing secured to the other end of the micrometer head and adapted to physically engage the other metallic object, a battery located in the housing, electrical contact means connected to one terminal of the battery and mounted at the end of the housing so as to engage the other metallic object when taking a measurement, and a sound generator and speaker assembly adapted for connection of the micrometer head to emit an audible signal when the electrical circuit is completed between the metallic objects.

Abstract: A carpentry measuring tool including two arms pivotally connected at adjoining ends thereof. The two arms are angularly adjustable with respect to one another, and are adapted for determining the angle formed between the interior portions of intersecting horizontal and vertical surfaces of a door or window frame. One of the arms is provided with an extendable slide portion on the end thereof and is adapted for measuring the distance between interior portions of opposed surfaces of the frame. The distal end of the slide portion contains a spring biased heel which may be retracted for removal of the one arm from within the door or window jam. The angular relationship of the two arms and the length of the one arm may be fixed so that these measurements may be transferred to a door or window which is to be hung in a measured door or window frame.

Abstract: Lead sight apparatus for shotguns is disclosed which comprises a pair of rings of a predetermined diameter spaced apart a predetermined distance from the barrel of a shotgun and extending outwardly from the shotgun barrel.

Abstract: A writing guide for writing letters and words in a transverse line on a sheet mounted on the flat surface of a baseboard, includes a rectangular frame movable along a detent rod carried by the baseboard. The frame is rotatable around the rod to enable the sheet to be placed on and removed from the baseboard. The frame has two rigid spaced rails joined by rigid end plates. A flexible string has two laterally movable sections disposed between and parallel to the rails to define a space for writing transversely along the sheet. The string may be connected in electric circuit with an electrically operable sounding device, power supply, and metal tip of a writing implement, to sound an alarm when the tip of the writing implement contacts one of the string sections.

Abstract: A sample material to be dehydrated is enclosed in a container transmissive to microwave and air is past through the container under a microwave radiation to preferentially remove the water content of the sample. The dehydrated sample may be incinerated by switching the air supply to an oxygen supply under the microwave radiation.

Abstract: Water is removed from a hydrocarbonaceous solid such as peat by contacting the solid with a liquid solvent relatively free of moisture such as benzene or toluene at elevated temperatures, i.e. 200.degree.-600.degree. F. and preferably at elevated pressures to prevent excessive volatilization, i.e. pressures of about 1 to about 100 atmospheres, to transfer at least a portion of the moisture in the solid to the solvent. The solvent is further characterized by its relative inability to dissolve appreciable amounts of water at low or ambient temperatures and its ability to dissolve substantially greater amounts of water at higher temperatures, i.e. 200.degree.-600.degree. F. After the solids are contacted with the solvent and while the solids and solvent are still at an elevated temperature, at least a portion of the solvent, now containing dissolved water, is removed from the solids to provide a product solids having a diminished water content.

Abstract: A chamber is isolated from ambient atmosphere by supplying a flow of inert gas to the entrance and/or exit of the chamber such as an oven for curing solvent borne resin coatings on a material passed therethrough. The inert gas is supplied at a substantially constant mass flow rate through an orifice which may be adjusted in opening or direction so as to enable the momentum of discharged inert gas to be controlled. A flow of gas is exhausted exteriorly of but in the vicinity of the chamber exit or entrance and the oxygen content of such flow is sensed. The sensed oxygen value is compared with a predetermined value and the difference is utilized to adjust the orifice to either increase or decrease the momentum of inert gas discharged therefrom. In this manner atmospheric oxygen is precluded from entering the chamber while only the amount (flow) of inert gas necessary to block such oxygen is utilized thereby minimizing the loss of inert gas from the chamber to ambient.

Abstract: A method of kiln drying timber in a kiln chamber by directing a restricted jet of hot air or gas over timbers in the stack and cyclically varying the direction of the jet in order to play the heated air or gas over the whole of the stack. A kiln for performing the method comprises a generally cylindrical kiln chamber having an elongate nozzle along one wall parallel to the axis of the cylinder and pivotable about an axis parallel to the axis of the cylinder; a group of fans arranged in a row parallel to the axis of the chamber draws gas or air from within the chamber and directs it along conduits one surface of which is a heat exchange surface to the nozzle where it is directed back into the kiln chamber. The heat exchange surface of the conduits may be heated in any known way, by means of heaters or by forming it as one surface of a water jacket.

Abstract: A process and apparatus for drying wet solid material are provided. The process comprises introducing material into a dryer, bringing it into contact with one side of a plurality of heated surfaces located therein and vaporizing liquid in the material. The liquid is withdrawn from the dryer, compressed to a pressure greater than in the dryer and returned to the other side of the heated surfaces where, upon condensation, latent heat energy is released therefrom and used to vaporize liquid in material on the opposite side of the heated surfaces, withdrawing the condensate from the heated surfaces and substantially dried solids from the dryer.The apparatus comprises a housing having entrance and exit openings and means for delivering material into and dried material therefrom located in the openings and isolating the dryer interior from the outside atmosphere. A plurality of hollow heat exchange means connected to an external heat source and to atmosphere are disposed in the interior of the dryer.

Abstract: A training aid of the simulator type for use in teaching the techniques of adjusting the cylinders of a multi-color rotary web printing press to achieve acceptable registration between the successive impressions forming a printed color page. Four superimposed positive colored film transparencies mounted on a light box provide facsimiles of the red, yellow, blue and black images successively printed on a web; and all but the black transparency are carried separately on adjustable frames which are movable to effectively simulate the endwise (button-to-gear), the circumferential and the cocking adjustments of the plate cylinders of a rotary press. Endwise and circumferential simulating movements are by electric motors each of which is controlled for forward and reverse drive by a manual switch that is identical with the switch on a press cylinder adjustment control panel, and the manual cocking control precisely simulates that for a press cylinder.

Abstract: A marksmanship training system is disclosed as comprising a viewing screen pon which a scenic picture having a predetermined target included therein is projected by a combination motion picture projector and film. A plurality of simulated rifles shoot laser light shots of different colors, respectively, at the target located within the image of said projected motion picture scene. A like plurality of receiver channels respond to the colors of said laser shots respectively, and as a result of being properly synchronized with said projector and film, determine and indicate the number of target "hits" for any given number of shots. A color television camera and video tape recorder monitor training exercises, and a video tape player permits the playback thereof for additional training purposes.

Abstract: A novel shoe incorporating a new sole and wedge-shaped arch support. The sole includes a plurality of sealed alveoli or air-chambers of different shapes which provide sufficient flexibility and resiliency to the shoe to reduce many of the common problems encountered by athletes. The alveoli are sealed in the sole by a mid-sole and an air-chamber member being sealed together in a simple and efficient manner.

Abstract: A shoe sole assembly of a resilient material body portion provided with absorbers energy formed as part of the body portion. The energy absorbers are defined by vertically disposed, spaced apart cell members extending from an upper surface to beyond a lower surface of the body portion to provide a bounded space. Each cell member is formed of an hollow compartment extending in part for the thickness of the body portion with its length depending upon the sole profile, the first end of the respective compartments at the upper surface of the sole body portion is initially open ended; whereas a hollow protuberance structure is at the lower surface of the body portion to enclose each cylindrical compartment at a second end. The protuberances extend beyond the lower surface to form contact areas with the ground surface when the sole assembly is used as part of a shoe.

Abstract: Heel supporting and cushioning member for footwear controlling the movement of foot/leg muscles in the form of removable, preferably disposable heel and foot shock absorber comprising a pliable coil filled with an elastomeric material resiliently flexing with the movement of the heel.

Abstract: A shoe insole comprising (A) a coarse mesh-like woven cloth backing made of monofilaments of a vinylidene chloride-type polymer, (B) a honeycomb-woven cloth intermediate layer made of monofilaments of the vinylidene chloride-type polymer, (S) a sheet prepared by coating a latex containing activated carbon powder, copper powder and magnetic powder on a non-woven cloth made of staple fibers of the vinylidene chloride-type polymer and/or a vinyl chloride-type polymer and heat-treating the coated cloth, and (D) a fine-woven cloth surface layer made of monofilaments of the vinylidene chloride-type polymer, the cloths (A), (B), (S) and (D) being laminated in order and the peripheral edge of the laminate being welded, and a process for producing the same.

Abstract: An athletic shoe particularly adapted for use in racing and training, having a tilted cleat configuration on the sole for contacting the running surface in a manner to provide good traction while effectively cushioning the foot and leg of the wearer when the foot strikes the ground.

Abstract: In a self-loading scraper, an elevator is provided with a linkage assembly for upward movement of the elevator about an axis offset from the center of the elevator. Spaced fixed stops are carried by the scraper bowl with a member on a bracket carried by the frame of the elevator engaging one of the fixed stops to limit downward movement of the elevator and a second member is movable with said bracket for engagement with the second fixed stop to limit upward movement of the elevator.

Abstract: A mounting for a slopeboard used to grade soil on an incline is provided near the edge on the backside of a bulldozer blade on an earth moving vehicle. The mounting includes a reinforcing gusset which receives both a connection from a transverse mounting beam secured to the front of a vehicle frame and also a rearwardly and outwardly extending slopeboard support. The slopeboard is mounted about an axis extending from another gusset at the edge of the bulldozer blade rearwardly to an extremity of the slopeboard support. An actuating hinge is connected atop the slopeboard support to accommodate a pressurized fluid actuating cylinder. The slopeboard can be rotated from a vertical orientation to an outwardly extended position below grade, always behind th edge of the bulldozer blade.

Abstract: Excavating apparatus including a boom having an idler pulley on its outer end and adapted to carry a digging chain in sliding arrangement with the boom is provided with skid shoe means and a nose piece which are disposed between the idler pulley and the outer end of the boom for slidably engaging and supporting the digging chain between the idler pulley and the lower surface of the boom. The skid shoe means defines a support surface that is substantially coplanar with the lower surface of the boom to support the links of the chain, and the nose piece has a lower surface generally parallel to the lower surface of the boom and is adapted to engage the digging chain rollers when the links of the chain are engaging the skid shoe means. Both the skid shoe means and the nose piece thus prevent the chain from causing excessive wear on the end of the boom.

Abstract: A recording tape carrier is attachable to a card or photograph and carries a magnetic recording tape that is usable in the recording slot of a magnetic recorder. A support card has a linear reference edge, and an abutment card is secured to a face surface of the support card to have an abutment edge extending along a mid-region of the support card and parallel with the reference edge. Adhesive covered by a release sheet is coated on the face surface of the support card in a region not occupied by the abutment card, and a strip of magnetic recording tape is secured to the support card or the abutment card to extend parallel with the reference edge. The release sheet is removable for securing the assembly to a card or photograph by means of the adhesive with the abutment edge engaging an edge of the card or photograph, and the magnetic tape is prerecordable and can be played back or recorded while secured to a card or photograph.

Abstract: A display element is mounted on a base to rotate less than 180.degree. between two limiting positions and to create mutually contrasting effects in the two positions. A magnetizable element mounted on the base extends parallel to the axis of rotation and exerts rotational torque at each of its free ends on one of two permanent magnets mounted on the display element to rotate outside of the free ends.

Abstract: A fisherman's accessory, for retrieving a fishing hook snagged among weeds or other objects during fishing; the device including a generally inverted, U-shaped wire, having inwardly bent, hook-shaped ends, and a pair of semi-circular guides across its center, for grasping around the fishing line as it is lowered to the hook; the device, in one design, including spring means to snap outwardly.

Abstract: A fishing apparatus is disclosed which employs a hollow fishing rod into and through which is pumped air by means of a battery operated pump connected to the butt end of the hollow rod by means of a hose. The air is discharged from the rod through a perforated tube attached to the end of the rod. When the air passes through the perforated tube, bubbles will be created to aerate the water and attract the fish. The pump may be activated by means of a switch located on the fishing pole grip. The fisherman may place the pole under the water and activate the switch to force air through the perforated tube at the end of the pole to create a diversion to attract the fish. A fishing lure is attached to a single action reel by means of a fishing line.

Abstract: A vibrating fishing lure which includes a hollow body carrying at least one set of hooks and a coil and breaker point vibrator combination mounted in the hollow interior of the body, which vibrator is activated by an attitude sensitive switch and is powered by a battery. The battery is removably positioned in a cylindrically shaped carrier and sleeve located inside the hollow body with access to the battery provided by a water tight threaded cap.

Abstract: An apparatus and method for controlling pests, particularly termites. The method involves the application of broad band, high-voltage electrical energy to termite shelter tubes, galleries and nests and to the bodies of the termites themselves. Killing of termites is accomplished directly by electroshock and indirectly by interference with the digestive processes of the termites. The apparatus is a probe gun incorporating circuitry for generating an electric signal having a voltage in the 100,000 volt range and a frequency range of 0-500 kHz.

Abstract: A fishing lure having a body member, a treble hook fastened to the body member, and a flap member pivotally connected to the nose portion of the body member. The nose portion of the body member is comprised of upper and lower substantially flat surfaces which intersect along a substantially horizontal straight line at the front most edge of the nose. The flap member is comprised of a forwardly extending flat bill portion and a pair of flat arm portions extending rearwardly from the side edges of the bill portion. The flat arm portions are pivotally connected to the nose of the body member.

Abstract: A savings toy box in which a coin may be placed in a predetermined position to be grasped by a hidden mechanism and pulled into the box.

Abstract: An amusement device for infants, babies and small children, especially intended to be mounted to a side wall of a crib. The device includes a transparent enclosure which in practice is filled with a liquid, and which contains at least one movable object such as a sphere or a simulation of a fish. The density of the object or objects is greater than the density of the liquid. A flexible resilient bellows extends from the lower end of the enclosure and a liquid transmission pipe or nozzle extends between the enclosure and the bellows. The bellows may be manually expanded by the infant or child, so that a body of the liquid is drawn from the enclosure into the bellows. A spring extends from the bellows to a lower fixed mounting, so that when the bellows is manually expanded, the spring is compressed against the lower fixed mounting and urges the bellows to an idle contracted shape, so that liquid is expelled from the bellows into the enclosure when the child releases the bellows expansion element.

Abstract: A toy projectile launching device having a main tubular member in fluid communication with an air pump, an air storage tank and a projectile launching housing rotatably coupled to the main tubular member. A valve member manually operable within the main tubular member, and with the valve member in a first position air from the air pump passes into the air storage tank; in a second position of the valve member, the pressurized air within the tank is released to propel a projectile within the housing. A third position of the valve member permits air from the air tank to be released in minute quantities to actuate an air-operated sounding device.

Abstract: A soft flying game disc comprising a limp, generally circular fabric locally annularly stiffened inwardly of the fabric peripheral edge margin in central air foil and peripheral spoiler skirt structure defining relation.

Abstract: An inflatable nursery toy typically consisting of a large generally barrel-shaped inflatable outer bag composed of soft, limp, flexible and non-resilient sheet material such as plastic, with donut-shaped cuffs at either end thereof. A smaller, separately inflatable cylindrical tube, usually composed of the same plastic material as the outer tube, is located within the barrel and is inclined lengthwise of the barrel relative to the axis of symmetry thereof. A plurality of balls are located within the cylindrical tube, and these balls travel lengthwise due to gravity, as a child rolls the barrel along the floor.

Abstract: A marionette which, when manipulated, has differential movement of at least one limb relative to the body of the marionette. This is accomplished by providing separate supports, i.e. strings, for the body and the limb which are characterized by being flexible and elastic manipulation strings, with the differential movement being accomplished by providing a first string for the body which has a different and preferably greater degree of elasticity, e.g. is heavier and thicker in cross-sectional area, than the second string attached to the limb. The strings extend to a common member, e.g. a ring, for placing the strings simultaneously under tension and in an extended rectilinear form. When under tension and extended, the first string assumes a rectilinear form aligned proximately with the center of gravity of the body.

Abstract: A toy vehicle having collectors thereon which are adapted to contact conductive strip's along a track is adapted to move at a substantially constant speed and provided with first and second guide means projecting laterally with respect to the vehicle body at spaced locations thereon. Each guide means terminates in a free end projecting downwardly for entry into a groove. Said guide means and groove cooperate to guide the vehicle around turns in the track. The guide means free ends and the grooves have a width differential which is less the width differential between each collector and its conductive strip. The guide means are mounted so that they may be mounted to project to one or to the other side of the vehicle.

Abstract: A sprayer which includes a plastic bag having in its upper end a perforated pipe and adapted to receive the end of a syringe and a draw string at the bottom for securing the bag around a flower pot to retain therein insecticidal sprays or powder.

Abstract: The agricultural chemical applicator of the present invention comprises a roller frame assembly having folding wing sections at opposite ends thereof. Rollers are mounted on each of the frames and include a liquid absorbing material which receives an agricultural chemical from a dispensing conduit located above the roller. A wiper engages the roller to prevent excess liquid from dripping off of the roller. The rollers are connected for driving engagement by interlocking lugs at the ends of the rollers adjacent the hinged joints of the roller wings.

Abstract: To apply herbicide to weeds extending above a crop, a nylon carpet on the cylinder of a roller applicator has herbicide applied to it as a tractor or other vehicle carries it through a field. The roller is held just above the crop where it contacts weeds and is rotated in the opposite direction as the tractor. A moisture sensor is spaced from the applicator on the roller and controls a valve that applies the herbicide to the roller to maintain a preset moisture level in the roller carpet. The amount of moisture is set by experimentation to permit an adequate amount of herbicide to be applied to various weeds without causing dripping from the point of contact on the roller by the weeds.

Abstract: A liner for plant pots covers substantially the entire interior surface of the pot and has upwardly extending finger grips which project through the top of the soil, permitting the liner to be gripped and drawn upwardly, raising the root and soil mass of a plant free of the surrounding pot, the flexible sheet member which comprises the liner being made in two or more distinct segments joined at the bottom such that they can easily be parted from the soil mass permitting the repotting of the mass, ordinarily into a larger pot or container.

Abstract: A storm window type closure which is adapted to be installed adjacent the interior side of an existing primary window unit. The present invention incorporates a main frame and associated runner assembly of such a low profile that the designed movement of the primary window unit may be accomplished without undue obstruction thereby allowing convenient access to the same. Additionally the present invention provides a substantial dead air space between the primary window and the storm window thereby increasing both the acoustic and thermal insulation qualities of the same.The present invention relates to windows and more particularly to storm windows which are adapted to be installed adjacent a preexisting primary window unit.

Abstract: A refrigerator door structure comprising a door hingedly mounted on a mullion is disclosed, one or more of which may be mounted in a suitable opening through the wall of a refrigerator compartment without a frame and with or without a starter mullion to close such opening while providing access therethrough. The door and mullion are designed to be inverted to provide for either right-hand or left-hand opening of the door. The packaging of the door structure with appropriate shelving elements is described.

Abstract: A combination hinge and opening bias mechanism for a closure of a vehicle such as a trunk deck lid including a hinge arm attached at one end to the closure with the other end guided by a horizontal track extending beneath an adjacent backlite of the vehicle body. Movement of the end of the hinge arm in the track is controlled by the pivoting of a torsion bar which extends laterally across the closure and with the end of a crankarm portion attached in pivotal relation to the body. During opening movement, the hinged edge of the closure pivots upward and slightly rearward as the elongated portion of the torsion bar rotates about the crankarm end. This upward movement is accompanied by rearward movement of the hinge arm in the track. The simultaneous dual pivoting of the closure moves the hinged edge portion of the closure rapidly upwardly in a substantially vertical direction so as not to contact the adjacent backlite of the vehicle which is only slightly spaced forward thereof.

Abstract: An electronic control apparatus for internal grinders wherein, with the workpiece fitted on slippers, a hole diameter gauger is provided. The gauger consists of two symmetric, linear transducers, by which the positions of both ends of a diameter are separately sensed. A measuring instrument is provided along the axis of wheelhead unit feeds, referred to the diamond truing position. The above defined electronic, control apparatus includes means by which the displacements of rotation axis from one, to another workpiece, caused by the changes in the diameter of same piece, are obtained from the signals of the two linear transducers. An analogic inverter, by which the sign of signal of one of the transducers is reversed, and an analogic adder, in which said reversed sign signal and the signal of other transducer are added with one another are provided.

Abstract: A tool for lapping internal surfaces of holes. Lapping tools conventionally have an expandable working portion for variable diameter operation. Known tools tend to expand in a barrel shape leading to inaccurate lapping. The invention seeks to avoid this by providing a working portion of a tubular tool with slots in a plurality of rows each having several slots. Slots in each row are staggered relative to those in adjacent rows.

Abstract: A system of automatically transferring vacuum uplift on the top of a roof to the underneath side of the roof membrane to shift the uplift pressure forces into the roof insulation and decking rather than on the roof membrane to prevent upward movement of the membrane and roof layer. A roof structure provided with one or more oneway or duckbill valves placed 3 feet in from the perimeter and on every outside corner at 50 foot intervals, which at their bases open into the area between a loosely laid membrane and the roof insulation in order to equalize the positive air pressure between the loosely laid membrane and the insulation with the minus air pressure which occurs on the top of the roof when wind blows across the roof.

Abstract: A roof construction utilizing thermoplastic panels and a method of making the same. The thermoplastic panels are arranged in edge contacting relation to span a roof underpanel supported by a roof frame. The thermoplastic panels carry anchor members projecting through openings in the underpanel and secured to the frame. The thermoplastic panels are bonded together at their margins. The thermoplastic panels at the roof margins have downturned flanges. Gutters have flanges which underlie and are anchored to the marginal panels at building eaves.The method involves formation of spaced openings in the roof underpanel adjacent to roof frame members to receive thermoplastic anchor strips whose upper ends contact the thermoplastic panels to be bonded thereto by the application of heat to the panel part contacted by the anchors. The lower ends of the anchors are secured to the frame members.

Abstract: A ceiling hanger adapted to be removably installed on a horizontal supporting strip of a tile ceiling structure wherein tile panels are provided with edge portions resting on opposed edge portions of the supporting strip. The hanger includes a plate having a U-shaped end portion embracing one edge of the supporting strip, a midportion underlying the supporting strip, and a retaining clip embracing the opposite edge of the supporting strip and retaining the plate midportion juxtaposed to the underside of the supporting strip. The plate further includes a distal hanger portion which is bent downwardly about a connecting portion of the plate to provide a support such as for hanging an advertisement or the like from the ceiling supporting strip.

Abstract: An insulation stop for use in buildings, such as a dwelling, having truss type roof, and which is capable of confining any type of insulating material to the area directly above the ceiling, while providing maximum space between the roof rafters and the underside of the roof for full flow of ventilation, to thereby materially reduce the energy required for air conditioning the building, as well as the cost involved. The invention consists of a single sheet, preferably of fibrous material, or which could be composed of light weight metal or plastic capable of being bent and folded. A plurality of such items are utilized to form the insulation stop for a complete building with one such item associated with and disposed in part between adjacent roof rafters.

Abstract: Spacing means for wall panels for preventing the buckling of said panels due to changes in climatic temperature, the panels having slotted portions along a top edge and one side thereof for receiving a flange mounted along the bottom edge and the other side of an adjacent panel, the improvement consisting of breakable spacing members extending at approximately right angle to the panel and mounted in proximity of the slotted portions whereby upon mounting one panel upon another, the spacing members of the upper panel engages and rests on the top edge of the flange of the lower panel in predetermined spaced relation to the upper edge portion of the slotted portion, said space permitting the expansion due to temperature changes of the panels without buckling same.