Method and apparatus for assembling and joining thermoplastic container sections by friction welding

Abstract

.Iadd.Method and apparatus for spin-welding thermoplastic articles in which two axially mating sections are driven in rotation relative to each other and then axially abutted in mating relationship. One of the two mating sections is chucked to an inertia member which is brought up to speed by a rotary drive. The rotary drive is uncoupled as the sections are moved into axial abuttment and the braking of the inertia member by the axial abuttment of the sections is transformed into frictional heat which welds the sections to each other. Apparatus for spin welding sections on a production line basis is disclosed. .Iaddend.

We claim:  .[.1. A method of joining thermoplastic hollow sections in end-to-end relation comprising: applying a drive to bring one of the sections to a state of relative rotation with the other section; releasing said drive while permitting said one section to spin; and bringing said sections into end-to-end engaging relation while said sections have relative rotation to weld the sections together with the controlled frictional energy created by their engaging relation during relative rotation..]. .[.2. A method of joining thermoplastic hollow sections in end-to-end relation comprising: applying a drive to bring one of the sections to a predetermined speed of rotation relative to the other section; releasing said drive while permitting said one section to spin; and bringing said sections axially into snug overlapping relation to weld 
     
        the lapped sections with a controlled frictional energy..]. 3. A method of forming thin-walled, thermoplastic containers comprising: differential pressure forming container upper sections in a web; differential pressure forming container lower sections in another web of a size such that said upper and lower sections would be received one by the other with an interference fit; .Iadd.advancing said webs to a separation station and .Iaddend.separating .Iadd.at said separation station .Iaddend.said upper and lower sections from said webs and forming openings in the tops of said upper sections .[.joining together open ends of the sections formed by their separation from the webs; applying a drive to bring certain of the sections.]. .Iadd.while said webs are at said separation station; advancing said separated upper and lower sections to a joining station; axially aligning mating pairs of upper and lower sections in axially spaced alignment with each other at said joining station and advancing the aligned sections through said joining station; driving one of each set of an aligned upper and lower section in rotation while said sections are moving through said joining station to bring the rotated section .Iaddend.to a predetermined state of relative rotation with .[.their.]. .Iadd.its .Iaddend.mating .[.sections releasing said drive while permitting said certain sections.]. .Iadd.section; discontinuing driving of the rotating section and permitting the rotating section .Iaddend.to spin .Iadd.freely; .Iaddend.and moving said .[.certain sections.]. .Iadd.freely rotating section .Iaddend.and .Iadd.its .Iaddend.mating .[.sections.]. .Iadd.section .Iaddend.relatively axially while said .[.certain sections are.]. .Iadd.rotating section is .Iaddend.spinning to bring the end edges .[.thereof.]. .Iadd.of said mating sections .Iaddend.into interference fitting, lapped engagement to generate a 
     
     
        frictional heat which weld said sections together in a circular seam. 4. In apparatus for assembling snugly fitting, mating thermoplastic container parts; first conveyor means for .Iadd.supporting opposed pairs of mating parts for coaxial rotation relative to each other and for .Iaddend.moving said .Iadd.opposed pairs of .Iaddend.mating parts through a path of travel in .Iadd.opposed .Iaddend.end-to-end .Iadd.paired .Iaddend.relation; .Iadd.driven rotation inducing .Iaddend.means .Iadd.extending alongside a first portion of said path for .Iaddend.driving one of .Iadd.each of .Iaddend.said .Iadd.opposed pairs of .Iaddend.mating parts .Iadd.in rotation .Iaddend.during .[.a.]. .Iadd.its transit of said first .Iaddend.portion of said path of travel only .[.for bringing.]. .Iadd.to bring .Iaddend.said one of said parts to a state of .[.relative.]. rotation .[.with the other.]. .Iadd.relative to the opposed .Iaddend.part; and means for moving .[.said.]. .Iadd.the last mentioned opposed .Iaddend.parts relatively axially into lapped end engagement .[.during another.]. .Iadd.as said last mentioned parts move along a second .Iaddend.portion of said path of travel, and while said one of said .[.mating.]. .Iadd.last mentioned .Iaddend.parts has relative rotation with the other .[.mating part.]. .Iadd.of said last mentioned parts 
     
     
        .Iaddend.to generate frictional heat welding the parts together. 5. Apparatus for assembling upper and lower, mating thermoplastic container shells comprising: carrier means movable through a path of travel; lower guides thereon receiving certain of said container shells, said lower guides including relatively rotatable parts; upper guides on said carrier means, and vertically aligned with said lower guides, receiving mating conveyor shells and vertically aligning them with said certain shells; drive means engaged by said lower guides during a portion of said path of travel to bring said certain shells to a predetermined speed of rotation relative to their mating shells; and means for moving at least one of said upper and lower guides axially during another portion of said path of travel, and while said certain shells have relative rotation with their mating shells to move the edges of mating shells into engagement and generate frictional heat welding the edges together.  .[.6. A method of joining thermoplastic parts comprising: rotating the parts relatively to impart a predetermined relative rotation energy thereto; releasing one of the parts to permit it to spin freely; and bringing said parts into engagement while said one part is spinning freely; said energy being such that it creates sufficient frictional heat to weld said parts together when they are brought into engagement but is less than that which would rupture the weld which is made..]. .[.7. Apparatus for joining thermoplastic parts comprising: means for holding one of said parts from rotating; means for revolving another part relative thereto at a speed to impart a predetermined relative energy thereto and then releasing the revolving part to spin freely; and means for moving said parts into engagement while said one part is spinning freely so that the relative rotation creates frictional heat which welds the parts together, the energy imparted being such that the relative rotation creates sufficient frictional heat to weld the parts together but is less than that which 
     
     
        would rupture the weld which is made..]. 8. In container forming apparatus; means for receiving a first web with thermoplastic container bottom parts formed therein and severing said parts from said web; first conveyor means leading therefrom; means for removing said parts to said first conveyor means and disposing them in inverted position thereon; means for receiving a second web with thermoplastic container upper parts having a bell-shaped edge formed therein, punching filling openings in the ends of said upper parts, and severing them from said web; second conveyor means leading therefrom; means for removing said upper parts to said second conveyor means and disposing them in inverted position; assembly means receiving said inverted bottom parts above said inverted upper parts and traveling them relatively axially into end-to-end lapped engagement; and means for friction welding said engaged parts together.  .[.9. In apparatus for assembling snugly fitting thermoplastic container top and bottom parts; means for holding a container top part and a container bottom part in axially spaced apart edge-to-edge disposition; drive means for relatively rotating said holding means to bring one of the parts up to a predetermined state of relative rotation with the other; means for disengaging said drive means and said holding means to permit said holding means for said one of said parts to spin freely; and means for substantially immediately moving one of said parts in an axial direction relative to the other to bring said parts into engagement while said parts have relative rotation and generate a controlled frictional heat for 
     
     
        welding the parts together in a circular seam..]. 10. In apparatus for assembling thermoplastic container top and bottom, mating shells in which the top shell edges receive the bottom shell edges but are of less internal diameter than the bottom shell edges; frame means; a rotary carrier mounted thereon and movable through an annular path of travel; means for revolving said carrier; lower vertical guide sleeve assemblies on said carrier mounted for vertical axial movement thereon; a stationary annular cam track on which said assemblies ride; each assembly including an upper sleeve for receiving one of said shells rotatably mounted on a lower sleeve; upper vertical guide sleeve assemblies for receiving mating shells mounted by said carrier for vertical axial travel in vertical alignment with said lower assemblies; a stationary annular cam track on which said upper assemblies ride; pulleys mounted on the upper sleeves of the lower guide assemblies to travel therewith on said carrier; and endless belt means supported by said frame means in the path of travel of said pulleys with said carrier through a portion of said path of travel so that said lower assemblies and the shells carried thereby are brought up to a predetermined speed of rotation as the lower assemblies are revolved and then are released when the pulleys travel beyond said belt means; one of the cam tracks being so configured that the upper and lower guide sleeve assemblies have relative axial movement to bring the edges of the top and bottom shells into interengaging relation after said lower assemblies pass beyond said endless belt means and the friction heat generated by said interengagement during relative rotation welds said 
     
     
        shells together in a circular seam. 11. The combination defined in claim 10 in which the upper sleeves of said lower guide assemblies and the upper 
     
     
        guide assemblies are fluted for receiving fluted container shells. 12. The combination defined in claim 11 in which said cam track for the lower guide sleeve assemblies has a sharp lobe joining said assemblies to seat the shells in the upper sleeves thereof prior to the time the pulleys engage said belt means.  .[.13. The method of joining together first and second thermoplastic parts, that includes loading said first part with rotatable means to augment the mass of the part itself, imparting rotation to said loaded first part to create a rotative inertia energy potential, then substantially freeing the loaded first part for rotation by the energy so created, and maintaining said first freely rotating part engaged with and in a state of relative rotation with said second part to frictionally heat and fuse the parts together to a state of non-relative rotatability..]. .[.14. The method of claim 13 in which the total energy utilized for said heating and fusion is derived substantially entirely from said rotating energy potential of the loaded first part..]. .[.15. The method of claim 13 in which said second part is held against rotation during said heating and fusion..]. .[.16. The method of claim 13 in which said parts are frictionally interengaged only after creation of said first member energy potential..]. .[.17. The method of claim 13 in which said parts are hollow sections, the end of one being received within and in engagement with the end of the other section..]. .[.18. The method of claim 13 in which said first section is loaded by a predetermined mass which is brought to predetermined rotative speed to create predetermined 
     
     
        rotative energy..]. 19. For joining together a succession of .[.parts.]. .Iadd.pairs .Iaddend.of .Iadd.axially extending .Iaddend.first and second thermoplastic parts.Iadd., .Iaddend.one of which has an annular surface receivable within a surrounding annular surface of the other part for engagement and fusion therewith but at varying degrees of tolerances between the surfaces of different pairs, the method that includes loading each first part with rotatable mass to augment the mass of the part itself, .[.imparting.].  .Iadd.feeding pairs of the first and second parts to pairs of holders positioning them in axially spaced apart relation and moving the holders and pairs consecutively bodily in a path of movement; as said parts are moving in said path of movement, consecutively engaging the holders for the first parts of each pair peripherally with a driven member having a drive surface disposed along a portion of the path of movement and traveling at a predetermined speed in view of said loading to impart .Iaddend.rotation to .[.the.]. .Iadd.each .Iaddend.loaded first part to create a rotative inertia energy potential, the .Iadd.continuing to move the pairs of holders and pairs of parts in the path of movement to a location beyond said drive surface and .Iaddend.substantially freeing the loaded first part for rotation by the energy so created, maintaining the freely rotating part with its said surface engaged with and in a state of relative rotation with the said surface of the second part to frictionally heat and fuse the parts together, and limiting relative rotation of the parts variably as between different pairs in accordance with their initial surface tolerances in relation to a uniform application of said energy potential.  .[.20. The method of claim 19 in which said parts are hollow container sections..]. .[.21. The method of claim 20 in which said second part is held against rotation during said heating and fusion and in which said surfaces are frictionally engaged only after creation of said first member energy potential..]. .[.22. The method of claim 21 in which said first sections are loaded by the same predetermined mass which is brought to the same predetermined speed to create the same predetermined potential rotative energy applicable to the successive container section pairs..]. .[.23. Apparatus for joining thermoplastic sections in end-to-end relation comprising: means for applying a drive to bring one of the sections to a state of relative rotation with the other section; means for releasing said drive to permit said one section to spin freely; the means for bringing said sections into end-to-end engaging relation after said drive is released and while said sections have relative rotation to weld the sections together with the frictional energy created by their engaging relation during relative rotation..]..Iadd. 24. In apparatus for assembling thermoplastic container top and bottom, mating shells in which the top shell edges receive the bottom shell edges but are of less internal diameter than the bottom shell edges; frame means; a rotary carrier mounted thereon and movable through an annular path of travel; means for revolving said carrier; lower vertical guide sleeve assemblies on said carrier mounted for vertical axial movement thereon; a stationary annular cam track on which said assemblies ride; each assembly including an upper sleeve for receiving one of said shells rotatably mounted on a lower sleeve; upper vertical guide sleeve assemblies for receiving mating shells mounted by said carrier for vertical axial travel in vertical alignment with said lower assemblies; a stationary annular cam track on which said upper assemblies ride; pulleys mounted on the upper sleeves of the lower guide assemblies to travel therewith on said carrier; and endless belt means supported by said frame means in the path of travel of said pulleys with said carrier through a portion of said path of travel so that said lower assemblies and the shells carried thereby are brought up to a predetermined speed of rotation dependent upon the mass of said sleeves on the lower guide sleeve assemblies and the pulleys thereon as the lower assemblies are revolved and then are released when the pulleys travel beyond said belt means; means for driving said endless belt means at a speed to bring said lower assemblies and the shells carried thereby to said predetermined speed of rotation; one of the cam tracks being so configured that the upper and lower guide sleeve assemblies have relative axial movement to bring the edges of the top and bottom shells into interengaging relation after said lower assemblies pass beyond said endless belt means and the friction heat generated by said interengagement duration relative rotation welds said shells together in a circular seam. .Iaddend. .Iadd. 25. Apparatus for assembling pairs of mating thermoplastic container shells comprising: carrier means; sets of first guides thereon receiving certain of said container shells; sets of second guides on said carrier means, and axially aligned with said first guides to provide a plurality of guide assemblies movable in a path of travel, receiving mating conveyor shells and axially aligning them with said certain shells to form pairs of shells to be mated; means for driving the carrier means and moving the first and second guides in paths of travel; driven means having a drive surface disposed along a portion of the path of travel of a guide in each guide assembly and traveling at a predetermined speed to bring one of the shells of each pair to a predetermined speed of relative rotation with its mating shell; and means for moving at least one of said first and second guides of each assembly axially during another subsequent portion of the path of travel of each guide assembly beyond said driven surface and while said certain shells have relative rotation with their mating shells to move the edges of mating shells into engagement and generate frictional heat welding their edges together. .Iaddend..Iadd. 26. The apparatus set forth in claim 25 in which said latter means is operated responsive to a predesignated travel of said guide assemblies through a continuous path of travel. .Iaddend. .Iadd. 27. Apparatus for assembling pairs of mating thermoplastic container shells comprising: carrier means; sets of first shell guides thereon receiving certain of said container shells; sets of second shell guides on said carrier means, and axially aligned with said first guides to provide a plurality of guide assemblies movable in a path of travel, receiving mating conveyor shells and axially aligning them with said certain shells to form pairs of shells to be mated; means for driving the carrier means and moving the first and second guides in paths of travel; drive means operable during movement of a guide assembly through a predetermined portion of said path of travel to drive one of the guides of each guide assembly and bring one of the shells of each pair to a predetermined speed of relative rotation with its mating shell; and means for releasing said drive means and moving at least one of said first and second guides of each assembly axially during another subsequent portion of the path of travel of each guide assembly to move the edges of mating shells into engagement while certain shells have inertial relative rotation with their mating shells to generate frictional heat welding their edges together. .Iaddend..Iadd. 28. Apparatus as set forth in claim 27 wherein said drive means is operable responsive to movement of each guide assembly through a predetermined portion of said path of travel, and said means for moving said guides to engage said shells is also operable responsive to a predetermined movement of each guide assembly in said path of travel. .Iaddend. .Iadd. 29. A method for assembling pairs of mating thermoplastic container shells comprising: loading certain shells to sets of first shell guides; loading mating shells to sets of second shell guides; axially aligning pairs of loaded first and second guides to provide a plurality of guide assemblies; moving the guide assemblies consecutively in a path of travel; applying a drive to one of the shells of each pair to bring it to a predetermined speed of relative rotation with its mating shell during a predetermined movement of each guide assembly in said path of travel; and releasing said drive and moving at least one of said first and second guides of each assembly axially during a subsequent portion of the path of travel of each guide assembly while certain shells have relative rotation with their mating shells to move the edges of mating shells into engagement and generate frictional heat welding their edges together. .Iaddend..Iadd. 30. The method of claim 29 wherein said drive is applied by moving one of said guides of each guide assembly into peripheral engagement with a driven means having a drive surface disposed along a portion of the path of travel of a guide in each guide assembly and whose drive speed is correlated with the speed of movement of said guide assemblies. .Iaddend. .Iadd. 31. A method of assembling pairs of mating thermoplastic hollow container sections comprising: loading certain container sections to sets of first guides; loading mating container sections which are to be individually assembled with each of said certain sections to sets of second guides; moving the loaded first guides consecutively in a first path of travel; moving the loaded second guides consecutively in a second path of travel, so related to the first path of travel that said first and second guides are axially aligned during at least a portion of said first and second paths of travel; applying a drive to bring one of the sections of each pair to be assembled to a predetermined speed of relative rotation with its mating section during a predetermined movement of the guide to which it has been loaded in its path of travel; and releasing said drive and thereafter moving appropriate pairs of said first and second guides axially together during a subsequent portion of the path of travel of each said guide, at a time when said first and second guides are axially aligned and while certain sections are permitted to have relative rotation with their mating sections to move the edges of mating sections into engagement and generate frictional heat welding their edges together. .Iaddend..Iadd. 32. Apparatus for securing pairs of mating thermoplastic container sections in axially assembled position comprising: a frame; sets of first container section guides, for receiving certain of said container sections, supported by the frame for movement in a first path of travel; sets of second container section guides, for receiving mating container sections, supported by the frame for movement in a section path of travel so related to said first path of travel that said first guides and second guides are axially aligned during at least a portion of said first and second paths of travel; means for moving the first and second guides in said paths of travel; drive means, operable during movement of each guide in one of said sets through a predetermined portion of its path of travel to drive each such guide and bring one of the sections of each pair to be assembled to a predetermined speed of relative rotation with its mating section; and means for releasing said drive means and moving appropriate first and second guides holding mating container sections relatively axially during another subsequent portion of the path of travel of each said guide, while said first and second guides are axially aligned, to move the edges of mating sections into engagement while certain sections have inertial relative rotation with their mating sections to generate frictional heat welding their edges together. .Iaddend.