Abstract: Lubricants containing a mixture of p,p'-dioctyldiphenylamine and substituted naphthylamines have improved antioxidant properties.

Abstract: Liquid crystalline compositions having the optical properties of the cholesteric mesophase are disclosed. The compositions comprise at least one nematic liquid crystalline material and at least one potentially cholesteric material which has a molecular structure which is similar to that of a nematic liquid crystal. Uses of the novel compositions are also described.

Abstract: Polyquaternary flocculants of average molecular weight, in excess of 10,000 are prepared by reacting a secondary amine with an epihalohydrin or diepoxide for use in flocculation of aqueous systems where ordinary cationic flocculants cannot be used.

Abstract: Polyquaternary flocculants of average molecular weight, in excess of 10,000 are prepared by reacting a secondary amine with an epihalohydrin or diepoxide for use in flocculation of aqueous systems where ordinary cationic flocculants cannot be used.

Abstract: Aqueous slurries or dispersions of starch are reacted with imadazolides of carboxylic or sulfonic acids to yield starch ester derivatives. These starch products can also be prepared in non-aqueous solvents or by a dry reaction process.

Abstract: A soy cheese having superior texture and body characteristics is made without milk solids by coagulating a fermented emulsion containing soy milk and a fat composition with about 0.05 to about 1.0 weight percent of a coagulant selected from the group consisting of aldonic acid lactones, uronic acid lactones, and mixtures thereof. A flavor producing proteolytic enzyme can be added to the soy milk before formation of the emulsion, to the emulsion prior to fermentation, or to the cooked curd without adversely affecting the texture and body of the resultant soy cheese.

Abstract: A closed loop transmission system is described in which a plurality of stations have access to each loop to write messages into and read messages from standard-sized message blocks transmitted around the loop. One station in each loop provides regeneration of all message blocks. The various loops are interconnected by switching stations which respond to address information at the head of each message block to selectively switch the block to the interconnected loop. The next required address is always substituted for the current address to simplify address recognition. Alternate and redundant routing are also provided for.

Abstract: A permanently knotted necktie comprises an elongated necktie body having a front face and a rear face, a permanent necktie knot and an extensible strap for detachably fastening the necktie around a person's neck. The permanent necktie knot and the necktie body may be formed from a single strip of material or the knot and body may be formed from separate strips of material. In the former case, the knot is formed by folding one end of the strip material back onto the front face of the body and then folding the free ends of the folded-back portion around the body and fastening them together at the rear face. In the latter case, the knot is formed by folding one end of the body strip material back onto the rear face of the body and then encircling the knot strip material around the folded-back portion and fastening together the ends of the knot strip material at the rear face.

Abstract: Disclosed herein is a tank valve for tank-type toilets comprised of a closed upper portion adapted to extend across the opening of a valve seat, and a hollow lower portion extending downwardly from adjacent the upper portion and adapted to extend within the opening of the valve seat. The lower portion is provided with a vent hole to permit air to escape therefrom to counteract the normal buoyancy of the tank valve. Such an arrangement allows the tank valve to close and terminate the flush without having to utilize the entire supply of flush water contained in the toilet tank.

Abstract: An elevated safety bathtub for use both by invalids and by persons without physical handicaps. The tube has a floor supported approximately at normal chair height and a side opening serving as an entryway through one of the walls of the tub, the bottom of the entryway being substantially at the same elevation as the floor of the tub. The entryway is provided with a water-tight barrier which may be moved out of the way to permit a person to enter the tub, and replaced once the person is inside the tub. The fact that the bottom of the entryway and floor of the tub are supported at approximately chair height enables the person to enter the tub by simply seating himself on the floor of the tub through the entryway as if he were seating himself in a chair. The person need not stand on the slippery tub floor. Several embodiments of the invention comprise adapter assemblies for converting existing conventional bathtubs to elevated bathtubs having the features of the present invention.

Abstract: The disclosure relates to swimming pools having a sheet metal exterior wall of substantially continuous oval or circular shape having a liner attached thereto for retaining water for the pool. The liner is secured to the pool wall area by means of an S-shaped bead receiver positioned over the top surface of the wall and held in place by means of a top clip which is attached to spaced uprights about the pool wall, the top clip having a substantially U-shaped portion of slightly larger width than the portion of the bead receiver overlapping the top surface of the wall. In this manner, the bead receiver is locked in position when the top clip is secured to an upright. The bead of the liner can now be positioned into the other half of the S-shaped head receiver after completion of assembly of the pool. The liner can also be removed and replaced without disassembling the pool as was required by the prior art.

Abstract: An elevated safety bathtub for use both by invalids and by persons without physical handicaps. The tub has a floor supported approximately at normal chair height and a side opening serving as an entryway through one of the walls of the tub, the bottom of the entryway being substantially at the same elevation as the floor of the tub. The entryway is provided with a water-tight barrier which may be moved out of the way to permit a person to enter the tub, and replaced once the person is inside the tub. The fact that the bottom of the entryway and floor of the tub are supported at approximately chair height enables the person to enter the tub by simply seating himself on the floor of the tub through the entryway as if he were seating himself in a chair. The person need not stand on the slippery tub floor. Several embodiments of the invention comprise adapter assemblies for converting existing conventional bathtubs to elevated bathtubs having the features of the present invention.

Abstract: A vibrator device intended to be mounted to the frame of a bed to provide a soothing vibratory action to the bed for slowly and gently nudging an individual sleeping in the bed from slumber to an awake condition, the vibrator having an electrically operated motor connected to an eccentric shaft weighted to produce a shaking vibratory motion with the free end of the shaft being rotatably secured in a pillow block type bearing. A clock mechanism with a dial indicator is provided for mounting on the bed for control of the electric motor.

Abstract: In a piece of furniture, a box spring or like structure comprising a substantially rectangular frame including longitudinally-extending side frame members and transversely-extending end frame members, and a plurality of supporting leg members secured to the box spring or like structure and supporting it substantially horizontally at a predetermined distance from a floor or other supporting surface, each of the supporting leg members comprising an elongated structural member formed into a generally W-shaped configuration wherein (1) the central portion is secured to a longitudinally-extending side frame member, (2) V-shaped portions adjacent each side of the central portion extend inwardly of the longitudinally-extending side frame members and downwardly to support the box spring or like structure substantially horizontally at a predetermined distance from a floor or other supporting surface, and finally (3) end portions extend still farther inwardly of the longitudinally-extending side frame members to be sec

Abstract: A cushioned seat structure comprising a resiliently compressible foam cushion having a pair of channel formations opening through the bottom face of the cushion and extending upward for a distance into the cushion body but terminating short of the cushion top face, the channels extending widthwise of the cushion along lines parallel to and spaced rearward from the cushion front face, one channel being spaced about midway back and the other channel being spaced roughly three quarters rearward. Underlying the cushion is a rigid support platform having a pair of slots therethrough aligned with the cushion channels where they open through the cushion bottom face, the slots being substantially congruent with the channels openings. The cushion lower surface is adhesively secured to the platform upper surface to prevent relative slippage in order to keep the cushion material out of the slots. A depending skirt portion of the cushion surrounds and cushions the side edges of the platform.

Abstract: An upholstered article and method in which a rigid pan to be upholstered is provided with a series of interior cutouts along an exterior edge, the cutouts defining an imitation interior edge to which is clipped, by metal clips, the upholstery material. The material is folded over the exterior edge and then into the cutouts over the interior imitation edge. This provides the pan with an upholstered exterior edge while maintaining a relatively thin profile of the upholstered article. Further, the upholstery material is provided with a series of tabs which are folded into the cutouts, the depth of the tabs defining a datum line to accurately position the material on the pan.

Abstract: Process for the heat fixation of dyestuffs on textile flat articles using a steamer with directional air or vapor stream wherein the circulating air or vapor stream is purified from dyestuff particles by intercalating a filter.

Abstract: Knitted articles, such as footlets, pantyhose and washing bags are provided, each includes a beaded portion forming the top thereof and a body portion connected to the beaded portion. The beaded portion is formed of a plurality of alternate and intermediate courses of Lycra yarn. The intermediate courses comprise a predetermined number of loops and the alternate course comprises a fraction of said predetermined number of loops. The alternate and intermediate courses alternate through the beaded portion starting with an alternate course. The body portion is knitted of a hosiery yarn and includes a plurality of courses, each of which includes the predetermined number of loops.The footlets and pantyhose once knitted in greige are inserted in a greige knitted bag and are dyed therein. The combination of the bag with the footlets or pantyhose therein is thereafter packaged for subsequent sale of the combination.

Abstract: The present invention relates to a boat shade comprising a cover and a frame for it formed of three inverted U-shaped components. Two of these inverted U-shaped components, carrying the cover, are arranged so as to flank the third inverted U-shaped component, to which they are hinged, and which is vertically erected and secured by its ends to the sides of a boat. Each of the hinges disposed at each end of each of the inverted U-shaped components, carrying the cover, is formed by an axle arranged at this end of the component and capable or moving in a horizontal direction outwardly in relation to the vertically erected component and a bushing mounted on it. A spring-actuated stop locks the axle in its extreme positions when the cover is either fully unfolded, or when it is partially folded, that is when one of the inverted U-shaped components, carrying the cover, is placed on the other component.

Abstract: End wall compartment closures for the stern parts of inflatable sponsons or pontoons for rubber boats are disclosed to enhance the gliding motion or planing action of the boat through the water and prevent distortion of the sponsons under variable inflation pressures while increasing the load carrying capacity and stability of such craft. In the several embodiments each of the elongated tubular sponsons that extend along the sides of a rubber boat is provided with a rigid-non-deformable closure wall that is essentially vertical to the longitudinal axis of the sponson or is in the form of an annular or tubular part or insert in the stern of the sponsons. The tubular inserts can be pot-shaped with circumferential grooves or ribs on the sides and have a bottom wall which forms the end compartment wall or closure wall for the sponson.

Abstract: A portable, recreational, buoyancy device comprising an integral rigid, ring-like floating unit having a central opening designed to accommodate the user's body, straps supporting the user in said opening, shoulder straps associated with the unit to suspend the unit from the shoulders of the user when in the opening, and oars mounted on the unit. This versatile device safely buoys and propels the user when floating in the water. When suspended from the user's shoulders, the upper surface of the rigid unit may provide a handy, readily accessible shelf for storage of equipment. The device at the same time provides much greater personal mobility for the user in water areas.

Abstract: The present process is especially suitable for economically producing cup nuts in large quantities by conventionally manufacturing the nuts and by deep drawing the cups separately from sheet metal in a single step to provide the cup with an outwardly facing chamfer along its edge surrounding the open end of the cup. In other words, the chamfer is produced as the result of the deep drawing step. The cup and the nut are connected by applying pressure and welding current whereby the pressure is applied just prior to, during and shortly after the welding to produce an intimate bond between the nut and cup. Due to the chamfer the welding bond forms an inwardly facing butt welding seam preferably running all around the edge of the cup, whereby a machining after the welding is avoided.

Abstract: The coke oven cleaner is capable of scraping particularly the entrance areas of a coke oven automatically to remove tar and the like adhered thereon completely, and comprises an upright stationary holding or support frame mounted on a door lifter, and a first scrapers-holding frame movable up and down the stationary holding frame and carrying first scrapers arranged to engage the door sealing surface of the coke oven entrance. A second scrapers-holding frame is movable with the first scrapers-holding frame and carries second scrapers engageable with the interior surfaces of the door frame and with the brick lining of the coke oven. Heat-blocking plates are movable with the first and second scrapers-holding frames. The second scrapers-holding frame comprises a pair of interdependent substantially parallel upright members interconnected by linkages, similar to toggle linkages, for movement laterally toward and away from each other by a hydraulic actuator or the like acting on one of the linkages.

Abstract: A toilet utensil for applying viscous toiletries comprising a sealed pouch which is made of a flexible and thin film and is filled with air or an elastic material.

Abstract: Tool comprises an elongated handle having a bifurcated extension projecting from one end and at least one elongated blade member affixed to and spanning said bifurcated extension substantially perpendicular to the longitudinal axis thereof. The blade member extends laterally beyond the branches of the bifurcated extension and constitutes working edges of the blade. The two opposed longitudinal outer edges of the blade member project from opposite sides of the bifurcated extension and constitute additional working edges of the blade. The tool is utilized by grasping the handle and passing the working edge of the blade over the surfaces of cut meat slices or pieces to remove bone dust, loose fat particles, etc., therefrom.

Abstract: Within a cleaning station for an electrostatic copier, a rotatable scavanging roll has a peripheral scavanging surface. Particulate matter, including toner entrained in an air stream, passes by the scavanger roll; the roll being electrically charged attracts a portion of the entrained particulate material. An air permeable filter is in cleaning contact with one circumferential portion of the scavanger roll for at least partially cleaning particulate matter therefrom, while simultaneously capturing entrained particulate material not attracted to the scavanging roll. In a preferred form, the cleansing filter has a relatively coarse mesh adjacent and contacting the scavanging roll and at an air-receiving portion. The filter has an exit portion of relatively fine mesh for capturing all particulate material.

Abstract: An airtight container, having two separated compartments, including an inlet to the first compartment and a flexible, gravel pick-up tube attached to the inlet. A cyclone separator is mounted on the second compartment with its separated particle outlet discharging into the second compartment. A connecting conduit connects the outlet of the first compartment with the inlet of the cyclone, so that the first compartment is a separator for gravel and dust and the second compartment is a dust container for the cyclone. A separate, high capacity air pump has its inlet connected to the cyclone's clean air outlet causing a flow of air through the unit for picking up gravel and dust through the flexible tube. For convenience the containers may be mounted on a truck, and both containers are unloaded through a common, sealable gate at the lower portion of the containers.

Abstract: A kit for converting an upright vacuum cleaner for use as an above-the-floor cleaner. The kit includes a housing which is removably fitted over the front of the cleaner chassis and includes an air chamber communicating the cleaner nozzle opening with one extremity of a hose. The kit includes a plurality of tabs and bosses on the housing for storing the hose and a plurality of accessory nozzles which are selectively exchangeable on the other extremity of the hose.

Abstract: A dog brush is provided for attachment to a conventional vacuum cleaner. Semi-flexible plastic bristles are curved in the direction in which the brush is drawn across a dog, whereby to cradle loose hairs transversely of the air flow into the vacuum cleaner, and thus most efficiently to pull the loose hairs into the vacuum cleaner. Restrictive orifices are provided to increase velocity of air flow further to facilitate picking up loose hairs. The handle of the brush is oriented for most efficient brushing of a dog.

Abstract: A bathtub closure means comprising horizontally extending panel means arranged to close about two-thirds of the distance between the top of a tub wall and a ceiling of normal height and arranged in open position to provide access and entry to the tub along virtually the entire length of the tub with substantial head room. A bathtub closure and method of assembly comprising jamb means, sill means, panel means, and panel guide means arranged and constructed to facilitate shipping, installing, assemblying and aligning in an opening to provide an effective closure of light weight and smooth operation.

Abstract: A freely rotatable disk formed with projections is held in a given position by a spring. The projections and the notches between the projections are selectively engageable by a handle element to deflect the disk, upon operation of the handle element, from its rest position and hold the handle element in an extended position permitting release of a locking bar effecting disengagement with a cooperating locking disk respectively secured to stringer or rail elements of a ladder, to permit the elements to pivot with respect to each other; the spring returning the disk upon movement of the handle to permit engagement of the locking bar, so that the disk, in one position, securely holds the handle and prevents spurious unlocking of the locking bar, and holds the handle in lock-release position to permit free pivoting of the ladder rail or stringer elements when in another position.

Abstract: A counterbalance hinge mechanism for a cabinet lid includes a stationary cabinet affixed hinge rod serving to rotatably support a pair of axially stationary lid mounting cam members and to slidably support a pair of non-rotatable cam followers. An adjustable spring assembly serves to bias the cam followers into engagement with the cam members, whereby to counterbalance gravity induced torque effects of the lid throughout a substantial portion of lid opening movement.

Abstract: A method and apparatus for filleting fishes is disclosed. The fish are cut on their underside by pairs of belly knives and pairs of rib knives, and by pairs of back knives on their dorsal sides. Between the belly knives and the rib knives are pairs of guide strips which guide the lower tail fin on the lower belly spines. Following the rib knives, a further pair of guides are provided and beneath these guides is a conveyor which acts on the underside of the backbone. Between the belly knives and the back knives, pairs of dorsal guides are provided in overlapping relationship. These individual guides are capable of adjustment to suit the shape of the fish.

Abstract: The turntable on which the silver can is mounted is connected to a piston of a compressed air cylinder and air pressure is used to maintain the piston and table in preset positions. When the silver can is filled to the preset weight, the table and piston move downwardly to activate either a switch in the path of the piston or a pressure responsive switch in the air line to the pressure side of the air cylinder.

Abstract: A fiber retrieving apparatus is incorporated into the upper wall of an enclosure mounted beneath the lickerin. A suction outlet in the lower wall of the housing is connected to a source of suction for continuously removing trash, motes, fly, short fibers and the like collected therein. An air inlet is provided in either the front wall or rear wall or both to replace the air removed from the housing so that good fibers are not drawn from the lickerin roll.

Abstract: An elongated separable fastener includes two similar sections formed of a resilient resin, each section including a longitudinally extending socket with a restricted throat and an elongated plug with an enlarged head which releasably engages the socket of the other section. Mating transverse recesses and projections are provided in the fastener sections to restrict their relative longitudinal displacement. In one form, each section includes a base web and a pair of transversely spaced longitudinal vertical plugs and longitudinally spaced projections projecting medially from the web, the space between one of the plugs and the projections defining a socket, and in another form, each section is U-shaped with enlarged heads on the side legs, longitudinally spaced transverse ribs being positioned at the base of the socket between the legs and the legs having longitudinally spaced transverse grooves.

Abstract: A separable fastener is disclosed which has the form of a tape having a plurality of laterally adjacent uniformly corrugated strips. Adjoining strips are staggered relative to one another so that the ridges of one strip are laterally aligned with the depressions or spaces between the ridges of adjoining strips, with the adjoining strips being joined together at their cross-over points. A second tape of identical construction can be joined to the first tape by merely pressing the two tapes together in a face-to-face relationship. There is also disclosed apparatus and a method for manufacturing the separable fastener which includes means for passing a strip of thermoplastic material through mutually engaging rolling dies which create the corrugations.

Abstract: A slide fastener element construction having a ladder-like structure of the type which is longitudinally folded on itself to form a finished row of coupling elements. The ladder-like structure basically includes longitudinally parallel spaced-apart base portions, a plurality of pairs of element-forming members projecting in opposed relation inwardly from the base portions, enlarged coupling head portions integral with the element-forming members and located innermost of the structure and bridge portions extending transversely of the structure for connecting the pairs of element-forming members.

Abstract: A slide fastener slider having on its upper wing a hook-shaped lug to which a pull tab is pivotally connected by snap fitting operation. There is also provided on the upper wing a projection spaced apart from the lug and adapted to fit in an opening formed in the pull tab when the latter is moved down into contact with the slider upper wing, thereby preventing the pull tab from becoming displaced relative to the horizontal axis of the slider body.

Abstract: A clamping device especially adapted for use with an automotive body or frame straightening device is disclosed wherein at least two clamping members each having a clamping jaw section at one end thereof and a clamping guide section at the other end thereof are held together by a retaining ring in such a manner that they may pivot about a ball disposed inwardly thereof, and within the space defined by the clamping guide sections is disposed a tapered member which has an outwardly tapered outer peripheral surface. When the tapered member is drawn or pulled outwardly, its tapered outer surface forces the clamping guide sections to move away from each other while forcing the clamping jaw sections to move toward each other, whereby the strong clamping force is produced.

Abstract: A saddle for a U-bolt clamp is constituted of a pair of tubular housings arranged to receive and slide axially upon the legs of a U-bolt having a semicircular bight, with the housings connected by a web portion consisting of a pair of parallel planar sections of sheet steel welded together in full face contact and extending transversely between the housings integral therewith. The upper (bight facing) edge of each planar section is curved as a semicircular recess curved on the radius of the U-bolt bight. The lower portion of each planar web section is, for the major portion of its length between the tubular housings, doubled back upon itself in flat face contact with the outer face of its associated planar web section, thus providing a double thickness for each web section throughout the area covered by the double back portion and materially reinforcing the entire web portion of the saddle both horizontally and vertically with four thicknesses of the sheet steel from which the saddle is made.

Abstract: A spreading and stretching apparatus for textile calender machines especially adapted for use with knitted and other tubular fabrics to prevent the pinching and tearing of the fabric as it is drawn into the calender rolls of the machine. Magnetic repulsion means are included to constantly bias and space a spreading and stretching frame away from the calender rolls as the fabric is drawn into the rolls over and around the frame. Variable speed feeding rollers enable controlled feeding of the tubular fabric into the calender rolls.

Abstract: A corpse positioner and restrainer comprising a substantially rigid member having weakened diagonal portions terminating in a cradling portion is disclosed. The corpse positioner and restrainer further includes cutout portions disposed on opposite sides of said cradling portion, and transverse portions extending from respective cutout portions substantially perpendicularly to opposite edges of the rigid member. The rigid member is adapted to be folded along said weakened diagonal portions until said transverse portions are vertically disposed beneath said cradling portion, whereby said cradling portion is collapsibly supported by said transverse portions.

Abstract: Textile strands are crimped by feeding them into and forwarding them within a laterally confining region that terminates in a laterally surrounding fine screen with a flared outlet end. The resulting strand-crimping apparatus or stuffer-crimper type utilizes flow of injected fluid to forward or assist in forwarding the crimped strand therethrough.

Abstract: Methods of and apparatus for treating yarn with a fluid material include a chamber through which the yarn is advanced and an injection nozzle for impinging fluid on the yarn as it advances through the chamber. The injection nozzle is registered with a fluid circulation system in which a dyeing substance or other fluid treating substance or material is circulated. Upon interrupting the circulation of the fluid treating material, a portion of the material is diverted into the chamber through which the yarn is advancing. By interrupting the circulation of the fluid treating material according to a selected pattern, the fluid treating material will impinge on the advancing yarn with a corresponding pattern. If it is desired to impinge treating materials having different characteristics, such as dyes of different colors, then a plurality of circuits may be utilized to direct the fluid materials into the chamber through which the yarn advances.

Abstract: Textile stock, natural or synthetic, is taken from a carding machine or garnett and delivered to a sloping web infeed pan. Jets of air from air nozzles direct and boost the textile web into a trumpet immediately in advance of pressurized web compressing and feed rolls. Such rolls deliver the web directly into the mouth of a steam injected one piece crimping or stuffing box having a pressurized hinged cover plate to regulate the crimp in the material. The crimped web, after discharging from the stuffing box, is elevated by a slatted conveyor for delivery to a slowly turning crimped stock receptacle into which the stock is coiled without stretching it.

Abstract: The efficient production of pervious low density carbon fiber reinforced composite articles is made possible through the use of the present invention. A fibrous open weave tape (as described) which is capable of undergoing conversion to a carbonaceous fibrous material is continuously passed in the direction of its length through a series of heating zones to form a fibrous carbon tape (preferably of graphitic carbon) wherein an open weave construction is maintained. At least one layer of the resulting fibrous open weave carbon tape may be impregnated with a thermosetting resinous material, and subsequently cured to form a pervious composite article.The composite articles exhibit a high specific modulus and strength, and are extremely lightweight. The lightweight composite articles may be utilized as structural elements, and are particularly suited for use as a facing sheet of an acoustic sandwich liner which serves as a noise suppression function in jet engines.

Abstract: A turret head for a rotary turning machine having a base rotatably mounted on a cross-slide for movement about a first axis. The turret head is mounted to the base for rotatable movement relative thereto about a second axis that is inclined to the first axis by an angle .alpha.. The turret head includes two rings or annular arrays of tool holders. Each ring has its tools disposed so that their axes lie on the surface of an imaginary cone having a vertex angle of 2.beta., such that .alpha. + .beta. = 90.degree.. The two imaginary cones have their axes coincide with the second axis and preferably the vertices of the cones coincide, so that the cones are mirror images of each other.

Abstract: A multiple-purpose machine tool wherein two spaced-apart upright frame members support three horizontal guide members which are disposed one above the other. The uppermost and lowermost guide members support two disks which are adjustable lengthwise thereof and flank an indexible drum for a group of equally spaced work clamping devices. The disks support the drum for indexing movement about a horizontal axis but prevent the drum from moving axially. Each guide member supports, at each side of the drum, several carriages each having a main slide which is movable lengthwise and a cross slide which is movable transversely of the respective guide member. At least some cross slides carry discrete motors which can rotate the respective tools and at least some clamping devices can be rotated by a drive which derives motion from the main prime mover of the machine tool.

Abstract: A reversible cutting insert, for a rotary cutting tool, is characterized by the provision thereon of two side-by-side bevel faces at each corner of the insert, which faces intersect edges at more than 90.degree. and intersect opposite polygonal surfaces at edges of less than 90.degree..