Back to results
US 4,127,378 AGranted
Apparatus for cold-forming plastic sheet
AssigneePeerless Machine & Tool Corporation
InventorWilliam R. Meadors
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneePeerless Machine & Tool Corporation
InventorWilliam R. Meadors
Estimating the term…
Apparatus for cold-forming a thermoplastic sheet to provide a circular container part such as a lid or dish comprising opposing concentric die members for engaging a sheet of thermoplastic material, the sheet being drawn around the circular edge of one of the die members to provide a concentric central portion and a concentric annular depending skirt having a proximal edge adjacent the central portion, an intermediate portion, and a distal free edge, providing an annular void in the die members adjacent the skirt. Apparatus is provided for moving the free edge toward the proximal edge while holding the proximal edge to buckle the intermediate portion into the void. The void has a tapered surface inclining radially outwardly and axially toward the proximal edge to hold the free edge radially inwardly, thereby to permit the intermediate portion to buckle outwardly into the void.
An apparatus for cold-forming sheet material comprising a plurality of opposing concentric die members including a lower central horn providing an upwardly facing die surface and an outer cylindrical wall, upper punch means for engaging said die surface, said upper punch means having an outer cylindrical wall, a lower annular draw pad disposed telescopically about said horn outer cylindrical wall, an upper annular draw pad disposed telescopically about said upper punch means outer cylindrical wall, said draw pads being telescopically movable upwardly and downwardly about said horn and punch means cylindrical walls, said draw pads cooperating to define an annular void opening toward said horn outer cylindrical wall and into which a depending annular skirt drawn from said material is buckled, said shirt being drawn about said horn outer cylindrical wall to have a proximal edge adjacent said die surface of said horn, an intermediate portion, and a free distal edge, said void having a first taperd surface, means for moving said draw pads upwardly together to move said void and distal free edge relatively toward each other to engage said tapered surface with said distal free edge and prevent radially outward curling deflection of said distal free edge, said tapered surface facing axially upwardly and radially inwardly toward said horn outer cylindrical wall and terminating at its radially inner extent adjacent said horn outer cylindrical wall to hold said distal free edge against said radially outward curling deflection adjacent said horn outer cylindrical wall, said tapered surface further terminating at its radially outer extent in an annular cavity having an upper wall spaced axially upward from said tapered surface.
An apparatus for cold-forming a buckled region intermediate the opposite edges of a skirt, said apparatus comprising means providing an outer wall against which said skirt is disposed, means for providing an inner wall disposed opposite said outer wall and against said skirt, means for holding one of said opposite edges against movement relative to said outer wall, means providing a void in said inner wall, said void opening toward said outer wall, said void having a tapered surface for engaging the other of said opposite edges, and means for moving said inner wall to move said other edge toward said one edge and buckle said intermediate region into said void, said tapered surface facing radially outwardly and axially toward said means holding said one edge to prevent radially inward curling deflection of said other edge, said tapered surface terminating at its radially outer extent adjacent said outer wall and at its radially inner extent remote from said outer wall.
Apparatus for cold-forming plastic sheet material into an item, the apparatus including means for forming an axially extending skirt spaced radially from an axis of a central portion of the item, the skirt having a proximal edge adjacent the central portions and a distal edge remote from the central portion, the proximal and distal edges being joined together by an intermediate portion of the skirt, means for holding the two edges against radially outward curling deflection and for moving the edges axially toward one another, the apparatus defining a void adjacent the intermediate portion of the skirt, the skirt intermediate portion buckling into the void as the two held edges are moved axially relatively toward one another.
Dependencies are inferred from the claim text.