Thermoforming machine with automatically mechanically operated web stripping element
First Claim
1. In a differential pressure thermoforming machine having a frame;
- mold assemblies mounted thereon for relative movement along an axis between a mold open and a mold closed position;
one of said assemblies having a female mold with a mold cavity;
means for feeding a heated deformable plastic web to be formed between said mold assemblies and adjacent said mold when the latter are in a mold open position;
a stripper element for the female mold for restraining the web from moving with the female mold when the latter is moved toward mold open position;
a stop supported by said frame;
a latch carried by said stripper and movable through a path of travel from a withdrawn position to a stop engaging position in which the latch and stripper are initially prevented by the stop from moving in the withdrawal path of the female mold; and
mechanism carried by the female mold assembly operable to effect movement of the latch to withdrawn position after a predetermined axial withdrawal of the female mold wherein the web is stripped from the mold to permit the stripped element to commence to move with the female mold assembly.
2 Assignments
0 Petitions
Accused Products
Abstract
In differential pressure synthetic plastics thermoforming machinery, mold support assemblies mounted on a frame have relative movement between a mold open and a mold closed position. Power operated mechanism is provided for axially moving at least the female mold support assembly, and the female mold on the assembly which carries a stripper element mounted for relative movement with the mold. Mechanism is provided for automatically latching the stripper element to the frame as the female mold moves toward mold closed position, and abutments are provided on the mold support assembly and latch for automatically unlatching it only after the female mold has withdrawn a predetermined distance in its movement toward mold open position.
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Citations
12 Claims
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1. In a differential pressure thermoforming machine having a frame;
- mold assemblies mounted thereon for relative movement along an axis between a mold open and a mold closed position;
one of said assemblies having a female mold with a mold cavity;
means for feeding a heated deformable plastic web to be formed between said mold assemblies and adjacent said mold when the latter are in a mold open position;
a stripper element for the female mold for restraining the web from moving with the female mold when the latter is moved toward mold open position;
a stop supported by said frame;
a latch carried by said stripper and movable through a path of travel from a withdrawn position to a stop engaging position in which the latch and stripper are initially prevented by the stop from moving in the withdrawal path of the female mold; and
mechanism carried by the female mold assembly operable to effect movement of the latch to withdrawn position after a predetermined axial withdrawal of the female mold wherein the web is stripped from the mold to permit the stripped element to commence to move with the female mold assembly. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- mold assemblies mounted thereon for relative movement along an axis between a mold open and a mold closed position;
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8. In a differential pressure thermoforming machine having a frame;
- mold support assemblies, at least one of which is movable on the frame and carries a female mold having a plastic web confronting face, mounted for relative movement between a mold open and a mold closed position along an axis of movement;
means for supporting a heated deformable synthetic plastic material between said mold support assemblies and adjacent the said mold face when the assemblies are in mold closed position; and
a stripper element for the female mold for restraining the plastic material when the female mold is moved toward mold open position;
the improvement wherein a first abutment is provided on the female mold support assembly and a second abutment is provided, the said abutments being in predetermined axially spaced position when the mold support assemblies are in mold closed position and moving into engagement when the said assemblies move relatively to mold open position, and one of said abutments is movable to normally restrain movement of the stripper element with the female mold and to release the stripper element to travel with the mold when the abutments engage. - View Dependent Claims (9)
- mold support assemblies, at least one of which is movable on the frame and carries a female mold having a plastic web confronting face, mounted for relative movement between a mold open and a mold closed position along an axis of movement;
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10. For use in a differential pressure thermoforming machine having a frame;
- mold support assemblies mounted for relative movement thereon along an axis of movement between an open and a closed position;
means for feeding a web of synthetic plastic material between the platen assemblies; and
means for moving at least one of the said assemblies axially, the combination comprising;a female mold adapted to be mounted on the latter support assembly carrying a stripper element mounted for relative movement therewith; a first abutment; a second abutment adapted to be mounted on the said latter support assembly at a predetermined distance from the first abutment when the support assemblies are in closed position to engage the first abutment when the support assemblies are moved relatively to open position; one of said abutments including a latch connected to restrain movement of the stripper element with the mold when the mold is withdrawn and cooperating with the other abutment to release the stripper element to travel with the mold when the abutments engage. - View Dependent Claims (11)
- mold support assemblies mounted for relative movement thereon along an axis of movement between an open and a closed position;
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12. A method of aiding the stripping process in a differential pressure thermoforming machine having a frame, mold support assemblies mounted for relative movement thereon along an axis of movement between an open and closed position;
- mechanism for feeding a web of synthetic plastic between the mold support assemblies when the latter are in open position, power operated mechanism for moving at least one of the mold support assemblies axially and a female mold on the latter assembly carrying a stripper element mounted for relative movement therewith;
the steps of;moving the female mold toward mold closed position and, as the mold approaches said position, latching the stripper element to the frame; differential pressurizing the plastic web to cause it to conform to the contour of the mold cavity; withdrawing the female mold from closed position while keeping the stripper element locked to the frame and thereby helping to strip the portion of the plastic web deformed into the mold cavity from the mold cavity; and after a predetermined interval engaging abutments on the mold support assembly and latch as the mold moves to open position to effect unlatching of the stripper element from the frame.
- mechanism for feeding a web of synthetic plastic between the mold support assemblies when the latter are in open position, power operated mechanism for moving at least one of the mold support assemblies axially and a female mold on the latter assembly carrying a stripper element mounted for relative movement therewith;
Specification