Clamp mechanism for differential pressure thermoformer
First Claim
1. In a differential pressure forming machine for forming articles in a web of thermoplastic material, said machine having a frame, a male mold and a female mold mounted on said frame for relative movement toward and away from each other, drive means including a rock shaft mounted on said frame for cyclically moving said molds toward and away from each other between a mold closed position wherein said molds are in opposed adjacent face-to-face relationship with each other and a mold open position wherein said molds are in spaced relationship to each other, said female mold having mold cavity defining means therein located within a given area on the face of said female mold facing said male mold, and said male mold having plug assist means adapted to project into said cavity means when said molds are in said mold closed position, means synchronized with said drive means for positioning an unformed section of a web of thermoplastic material between said molds when said molds are in said mold open position, and clamping means for clamping said section of said web against saidface of said female mold around the perimeter of said given area upon movement of said molds from said mold open position;
- the improvement wherein said clamping means comprises clamping ring means mounted on said frame for movement independently of said molds to and from a clamping position wherein said ring means is operable to clamp said web against said face of said female mold around the perimeter of said given area, and cam means mounted on said rock shaft engageable with cam follower means coupled to said clamping ring means for driving said clamping ring means to and from said clamping position in movement synchronized with the opening and closing of said molds.
1 Assignment
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Accused Products
Abstract
A mechanism for clamping a web of thermoplastic material against the face of a female mold prior to closure of the mold includes a clamping ring assembly mounted on the machine frame for movement relative to the frame independently of the molds. The clamping assembly is driven to and from its web clamping position by a cam mounted on the rock shaft which drives the molds between their open and closed positions and a constant radius section on the cam holds the clamp in its clamping position throughout a substantial portion of the operating cycle.
29 Citations
8 Claims
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1. In a differential pressure forming machine for forming articles in a web of thermoplastic material, said machine having a frame, a male mold and a female mold mounted on said frame for relative movement toward and away from each other, drive means including a rock shaft mounted on said frame for cyclically moving said molds toward and away from each other between a mold closed position wherein said molds are in opposed adjacent face-to-face relationship with each other and a mold open position wherein said molds are in spaced relationship to each other, said female mold having mold cavity defining means therein located within a given area on the face of said female mold facing said male mold, and said male mold having plug assist means adapted to project into said cavity means when said molds are in said mold closed position, means synchronized with said drive means for positioning an unformed section of a web of thermoplastic material between said molds when said molds are in said mold open position, and clamping means for clamping said section of said web against saidface of said female mold around the perimeter of said given area upon movement of said molds from said mold open position;
- the improvement wherein said clamping means comprises clamping ring means mounted on said frame for movement independently of said molds to and from a clamping position wherein said ring means is operable to clamp said web against said face of said female mold around the perimeter of said given area, and cam means mounted on said rock shaft engageable with cam follower means coupled to said clamping ring means for driving said clamping ring means to and from said clamping position in movement synchronized with the opening and closing of said molds.
- View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. In a differential pressure forming machine for forming articles in a web of thermoplastic material, said machine having a frame, a matching mold and a female mold mounted on said frame for relative opening and closing movement, drive means mounted on said frame for cyclically relatively moving said molds between a mold closed position wherein said molds are in opposed adjacent face-to-face relationship with each other and a mold open position wherein said molds are in spaced relationship to each other, said female mold having mold cavity defining means therein located within a given area on the face of said female mold facing said matching mold, means for positioning an unformed section of a web of thermoplastic material between said molds when said molds are in said mold open position, and clamping means for clamping said section of said web against said face of said female mold around the perimeter of said given area upon relative movement of said molds from said mold open position;
- the improvement wherein said clamping means comprises a sub frame, carrying clamping ring means, mounted on said frame for movement independently of said molds to and from a clamping position wherein said ring means is operable to clamp said web against said face of said female mold around the perimeter of said given area, and clamp means operating means, driven by said drive means, linked to said sub frame for driving said clamping ring means to and from clamping position in movement synchronized to and with the opening and closing of said molds; and
spring means interposed between said sub frame and clamping ring means which is slightly compressed when said clamping ring means is driven to clamped position.
- the improvement wherein said clamping means comprises a sub frame, carrying clamping ring means, mounted on said frame for movement independently of said molds to and from a clamping position wherein said ring means is operable to clamp said web against said face of said female mold around the perimeter of said given area, and clamp means operating means, driven by said drive means, linked to said sub frame for driving said clamping ring means to and from clamping position in movement synchronized to and with the opening and closing of said molds; and
Specification