# US 4,398,879 A · On-site fabricating of plastic pipe fittings > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,398,879 A - Document ID: US4398879A - Status: Granted - Kind: A - Application number: 06/275,412 - Filed: 1981-06-19 - Granted: 1983-08-16 - Earliest claimed: 1981-06-19 - Inventors: Paul R. DuPont; Craig R. Nelson - Web page: https://patentgrep.com/patent/US4398879A ## CPC - B29C 66/003: {Protecting areas of the parts to be joined from overheating (B29C66/348, B29C66/8744 take precedence)} - B29B 13/025: {Tube ends} - B29C 57/00: Shaping of tube ends, e.g. flanging, belling or closing; Apparatus therefor {, e.g. collapsible mandrels} - B29C 65/562: {using extra joining elements, i.e. which are not integral with the parts to be joined (using plastic snap elements B29C65/58; using plastic rivets B29C65/601)} - B29C 66/1122: {Single lap to lap joints, i.e. overlap joints (B29C66/45, B29C66/472, B29C66/52272 take precedence)} - B29C 66/1222: {comprising at least a lapped joint-segment} - B29C 66/1224: {comprising at least a butt joint-segment} - B29C 66/1312: {Single flange to flange joints, the parts to be joined being rigid (the parts to be joined being flexible B29C66/133)} - B29C 66/5221: {for forming coaxial connections, i.e. the tubular articles to be joined forming a zero angle relative to each other} - B29C 66/5344: {said single elements being substantially annular, i.e. of finite length, e.g. joining flanges to tube ends (B29C66/5346 takes precedence)} - B29C 66/73921: {characterised by the materials of both parts being thermoplastics} - B29L 2023/22: {Tubes or pipes, i.e. rigid (bent tubes not for use as pipe couplings B29L2023/004)} - 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) - B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES ## Abstract A portable apparatus for reforming plastic pipe ends is disclosed. The apparatus includes a heat sink clamp and depth collar for locating said clamp a predetermined distance from the end of the plastic pipe end. This heat sink clamp substantially limits axial heat penetration from an oven into the plastic pipe so as to permit the reshaping of the pipe end into a sanitary flow end, i.e. an end having imperfection-free contours. ## Claims ### Claim 1 A portable plastic pipe-end reforming apparatus comprising a planar table having mounted thereon an oven having a uniformly heated internal cavity for accommodating therein a range of different pipe diameters, segmented heat-sinking clamp means including a thermal barrier portion disposed opposite said oven cavity and a highly thermally conductive section for intimately embracing a predetermined length of said plastic pipe, said heat-sinking clamp means being adapted to sharply limit the axial heat penetration from said oven into said plastic pipe and a forming station having a die for embossing a sanitary flow pipe contour parting surface on said pipe end. ### Claim 2 (depends on 1) A pipe-end reforming apparatus according to claim 1, further including depth collar means for defining a further length of said pipe, said collar being adaptable to embrace said pipe from the end thereof to locate said heat-sinking clamp means and being removable to permit said further length of said pipe-end beyond said predetermined length embraced by said heat-sinking clamp means to protrude into said oven cavity, said clamp means limiting said axial heat penetration substantially solely to said further length. ### Claim 3 (depends on 2) A pipe-end reforming apparatus according to claim 2, wherein said oven includes a plurality of thermostatically controlled heating elements and a motor driven fan for evenly distributing the air heated in said cavity by said heating elements. ### Claim 4 (depends on 2) A pipe-end reforming apparatus according to claim 2, wherein said heat sinking clamp means is dimensioned to have said highly thermally conductive section embrace said predetermined length and said depth collar is positioned to define said further length so that said end of said pipe protruding into said oven is approximately one-fifth of said predetermined length. ### Claim 5 (depends on 2) A pipe-end reforming apparatus according to claim 2, wherein said oven is slidably mounted on said table and wherein said pipe-end is heated in said oven cavity to relieve the original extrusion stresses therein over said length protruding into said cavity when said oven is advanced toward said heat sinking clamp means. ### Claim 6 (depends on 1) A pipe-end reforming apparatus according to claim 1, wherein said heat sinking clamp means comprises a receptacle affixed to said table opposite said oven cavity, detachable block means insertable into said receptacle, said block means having separable segments contoured to match the outer circumference of said pipe, and clamp means for bringing said contoured segments into intimate contact with said outer circumference of said pipe. ### Claim 7 A portable apparatus for reforming the end of an originally extruding plastic pipe to the contours of a sanitary flow pipe section, comprising: a planar table having an oven including a uniformly heatable internal cavity, means including a heat sink clamp and depth collar for locating said clamp a predetermined axial length from the end of said plastic pipe, positioning means for introducing said predetermined axial length of said plastic pipe projecting into said oven cavity for the uniform relieving of extrusion-induced stresses in said pipe, and a forming station for embossing a sanitary flow pipe contour having a sharply defined parting surface (12f, 12g or 134, 13g) into said stress-relieved end portion of said pipe and for defining a sanitary flow external flange contour (22) on the external periphery thereof.