# US 4,394,342 A · Forming plastic articles having strands by stretching > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,394,342 A - Document ID: US4394342A - Status: Granted - Kind: A - Application number: 06/193,729 - Filed: 1980-10-03 - Granted: 1983-07-19 - Earliest claimed: 1979-10-09 - Assignees: P.L.G. Research Limited - Inventors: Frank B. Mercer - Web page: https://patentgrep.com/patent/US4394342A ## CPC - B65D 1/38: Baskets or like containers of skeleton or apertured construction {(crates for bottles or like containers B65D1/243)} - B29C 51/00: Shaping by thermoforming {, i.e. shaping sheets or sheet like preforms after heating}, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor {(blow moulding of tubular preforms B29C49/00, deforming of tubular or hollow preforms B29C67/0014)} - B29D 28/00: Producing nets or the like, {e.g. meshes, lattices}(by knotting D04G) - B29L 2031/713: {Baskets} - B29L 2031/737: {Articles provided with holes, e.g. grids, sieves (nets B29L2028/00)} - Y10S 264/81: Plastic net - Y10S 425/048: Sheet clamping - Y10S 425/053: Stretch - Y10S 428/91: Product with molecular orientation - Y10T 428/24273: including aperture - Y10T 428/24306: Diamond or hexagonal - Y10T 428/24314: Slit or elongated - B65D: CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00) - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract In order to make a non-planar plastics material article, a starting material has at least one ring of holes or depressions and is pressed so that the part which is within the ring is moved generally at right angles to the plane of the ring with respect to the part which is outside the ring, thereby stretching, into orientated strands, zones between adjacent holes or depressions in the ring; in the finished article, the strands interconnect the two parts. ## Claims ### Claim 1 A method of making a plastic material article, comprising providing a piece of plastic starting material having a plurality of generally coaxial rings of holes or depressions therein, each hole or depression being separated from its adjacent hole or depression in the same ring by a zone, the sum of the cross-sectional areas of all the zones in a given ring being approximately equal to the sum of the cross-sectional areas of each other ring, the cross-sectional area of each zone being the multiplication product of (a) the shortest distance between adjacent holes or depressions and (b) the average thickness of the plastic starting material along that distance, said piece being substantially all at substantially the same temperature, and moving a first part of said piece which is within the rings with respect to a second part which is on the other side of the rings, in a direction generally at right angles to notional planes which generally intersect the holes or depressions of the respective rings, thereby stretching said zones of said given and other rings into oriented strands, said zones in the given ring all being stretched to substantially the same stretch ratio and said zones in the other rings all being stretched to substantially the same stretch ratio. ### Claim 2 (depends on 1) The method of claim 1, wherein there is a plurality of said rings of holes or depressions in the starting piece, the rings being coaxial and the center lines of the rings being geometrically similar, wherein there is an annular zone between two said rings of holes or depressions in the starting piece, said moving being terminated when said annular zone is not substantially stretched. ### Claim 3 (depends on 1) The method of claim 1 wherein those parts of the starting piece which are stretched during said moving have parallel faces. ### Claim 4 (depends on 1) The method of claim 1 wherein the starting piece is stretched by parts thereof being moved in two opposite directions with respect to the second part. ### Claim 5 (depends on 1) The method of claim 1 wherein each generally coaxial ring of holes or depressions has a different perimeter length. ### Claim 6 (depends on 1) The method of claim 1 wherein each generally coaxial ring of holes or depressions has approximately the same perimeter length. ### Claim 7 A method of making a plastic material article, comprising providing a piece of plastic starting material having a plurality of generally coaxial rings of holes or depressions therein, the sum of the shortest distances between each respective pair of adjacent holes or depressions in a given ring being substantially equal to that in each other ring, and the plastic starting material zones between adjacent holes or depressions of the given ring and other rings being all substantially of the same thickness, said piece being substantially all at substantially the same temperature, and moving a first part of said piece which is within the rings with respect to a second part which is on the other side of the rings, in a direction generally at right angles to notional planes which generally intersect the holes or depressions of the respective rings, thereby stretching said zones of said given and other rings into oriented strands, said zones in the given ring all being stretched to substantially the same stretch ratio and said zones in the other rings all being stretched to substantially the same stretch ratio. ### Claim 8 (depends on 1, 7) The method of claim 1 or 7, wherein there is a plurality of said rings of holes or depressions in the starting piece, the rings being coaxial and the center lines of the rings being geometrically similar, and wherein there is an annular zone between two said rings of holes or depressions in the starting piece, which annular zone twists around so that its faces are roughly aligned with said oriented strands on either side of said annular zone. ### Claim 9 (depends on 1, 7) The method of claim 1 or 7, wherein there is a plurality of said rings of holes or depressions in the starting piece, the rings being coaxial and the center lines of the rings being geometrically similar, wherein there is an annular zone between two said rings of holes or depressions in the starting piece, said moving being terminated when the orientation of the strands passes into, but not right through said annular zone, said annular zone not being otherwise substantially stretched. ### Claim 10 (depends on 1, 7) The method of claim 1 or 7, wherein the starting piece is in a preformed, non-oriented shape having a bottom and sides, said rings of holes or depressions being formed in the sides, the sides being deepened during said moving to form said oriented strands. ### Claim 11 (depends on 7) The method of claim 7 wherein the shortest distance between adjacent sides of the holes or depressions in one ring is substantially constant and substantially equal to that in another ring. ### Claim 12 (depends on 7) The method of claim 7 wherein each generally coaxial ring of holes or depressions has a different perimeter length. ### Claim 13 (depends on 7) The method of claim 7 wherein each generally coaxial ring of holes or depressions has approximately the same perimeter length.