Fluid pressure operated apparatus for mounting a differential pressure mold on a platen

• US 4,969,812 A
• Filed: 05/30/1989
• Issued: 11/13/1990
• Est. Priority Date: 05/30/1989
• Status: Expired due to Fees

• Current Assignee: Brown Machine, LLC (Brown Machine Group Holdings LLC)
• Original Assignee: John W. Ryan
• Inventors: Brown, Gaylord W.
• Primary Examiner(s): Woo, Jay H.
• Assistant Examiner(s): Mackey, James P.
• Application Number:
  US07/358,438
• Time in Patent Office: 532 Days
• Field of Search: 425/450.1, 425/451.2, 425/451.9, 425/589, 425/590, 425/595, 425/395, 425/408, 425/389, 425/390, 425/394, 425/406, 425/412, 425/398, 425/DIG. 48, 425/416, 100/219, 100/269 R, 100/270, 264/297.5, 264/325
• US Class Current: 425/398
• CPC Class Codes: B29C 33/202 Clamping means operating on closed or nearly closed mould parts, the clamping means being independently movable of the opening or closing means clamping devices for injection moulding machines B29C45/64
• CPC Class Codes: B29C 33/305 Mounting of moulds or mould support plates handling of moulds B29C31/006; mounting of moulds for injection moulding B29C45/1742
• CPC Class Codes: B29C 51/38 Opening, closing or clamping means

Abstract

A differential pressure machine for differentially pressure forming an article in a sheet of thermoplastic material including a frame, upper and lower platens movable on the frame between spread and less spread positions. Mechanism is provided for moving the platens between the spread and less spread positions for releasably locking the platens in the less spread positions. Upper and lower, opposed differential pressure molds mounted on the upper and lower platens, respectively, for movement therewith between open positions and closed positions for engaging opposite sides of a thermoplastic sheet of material and differentially pressure forming an article therein. Fluid pressure operated mechanism mounts one of the upper and lower molds on one of the upper and lower platens for movement therewith and for movement relative thereto when the platens are locked in the less spread positions to incrementally move one of the molds relative to one of the platens toward the other of the molds to tightly sandwich the sheet between the upper and lower molds including a variable volume, fluid pressure chamber between confronting portions of one of the platens and one of the molds. The invention is characterized in this that a separator plate is disposed in the chamber between the confronting portions of one platen and one mold and opposed annular seals are disposed between, and in sealing engagement with, the separator plate and the one platen and the one mold.

Claims

1. Apparatus for differential pressure forming thermoplastic objects from at least one thermoplastic sheet comprising:

a frame;

means for supporting a thermoplastic sheet on said frame at a forming station;

a pair of opposed, cooperating mold means for engaging opposite sides of said sheet to differentially pressure form an object in said sheet;

means for relatively moving said mold means between spaced apart, open positions removed from said sheet and closed positions engaging opposite sides of said sheet;

one of said mold means including

a platen;

a mold member;

means mounting said mold member in spaced relation with said platen for movement therewith and for movement relative thereto between a non-sealing position and a sheet sealing position comprising;

a gap defined by opposing portions of said mold member and said platen;

at least one separator plate disposed in said gap between said opposing portions of said mold member and said platen;

a first endless yieldable seal means sandwiched between said opposing portions of said mold member and one side of said separator plate, to define an air pressure cavity on one side of said separator plate;

a second endless yieldable seal means sandwiched between said opposing portion of said platen and the opposite side of said separator plate to define a second air pressure cavity on said opposite side of said separator plate; and

fluid actuated means for incrementally moving said mold member relative to said platen from said non-sealing position toward said sheet to said sealing position to tightly sandwich said sheet between said pair of mold means and insure sealing engagement between said pair of mold means and opposite sides of said sheet comprising;

means for admitting fluid under pressure to each of said cavities to move said mold member relative to said platen from said non-sealing position to said sealing position.

2. The apparatus set forth in claim 1 wherein said separator plate is perforated.

3. The apparatus set forth in claim 1 wherein each of said seal means comprises an O-ring.

4. The apparatus set forth in claim 3 wherein said opposing portions of said mold member and said platen each include an annular slot receiving one of said O-rings.

5. The apparatus set forth in claim 4 wherein the diameter of each O-ring is less than the combined thickness of said air pressure cavities on opposite sides of said separator plate.

6. Apparatus for differential pressure forming a thermoplastic object from a thermoplastic sheet comprising:

a frame;

means for supporting a thermoplastic sheet on said frame at a forming station;

a pair of opposed cooperating mold means for engaging opposite sides of said sheet at said forming station to differentially pressure form an object in said sheet;

means for relatively moving one of said mold means toward and away from the other of said mold means between spaced apart, open positions and closed positions engaging opposite sides of said sheet including

a pair of opposed platen means for mounting said pair of opposed mold means;

means for moving said platen means on said frame, toward and away from each other, to move said mold means between said spaced apart, open positions and said closed positions;

means mounting at least one of said mold means on one of said platen means for movement therewith, but in spaced relation for movement relative thereto, when said mold means are in said closed positions, between a sealing, spread position spread from said one platen means and a non-sealing less spread position;

means between said one mold means and said one platen means defining a variable volume fluid chamber comprising

a separator plate between said one mold means and said one platen means;

a pair of annularly extending resilient means sandwiched between opposite sides of said separator plate and said one mold means and said one platen means; and

means for admitting fluid under pressure to said chamber to move said one mold means away from said one platen means from said non-sealing position to said sealing position to tightly sandwich said sheet between said pair of mold means.

7. Apparatus for differential pressure forming a thermoplastic object from a thermoplastic sheet comprising:

a frame;

means for supporting a sheet of thermoplastic material at a forming station;

a pair of opposing, differential pressure mold means for engaging opposite sides of said sheet at said forming station to differentially pressure form said object;

means for relatively moving said mold means between spaced apart positions and closed sheet engaging positions comprising

upper and lower mold mounting platens movable on said frame toward and away from each other

means mounting one of said mold means on one of said platens for movement therewith but in spaced relation relative thereto to allow said one mold means to move relative to said one platen when said mold means are in said sheet engaging positions between sealing spread positions in which said one mold means is spread from said one platen means and in sealing engagement with said sheet and less spread non-sealing positions;

means for moving said one mold member from said less spread position to said spread position when said mold means are in said sheet engaging positions including a separator plate disposed between said one mold means and said one platen, a pair of yieldable means disposed between opposite sides of said plate and each of said one platen and said one mold means respectively to define an expansible and contractible fluid pressure chamber between said one mold means and said one platen; and

means for admitting fluid under pressure to said chamber to expand said chamber when said pair of mold means are in said closed sheet engaging positions to move said one mold means away from said one platen to said sealing position to tightly sandwich said sheet between said pair of mold means and insure said mold means are sealed to opposite sides of said sheet.

8. A differential pressure machine for differentially pressure forming an article in a sheet of thermoplastic material including

a frame;

upper and lower platens movable on said frame between spread and less spread positions;

means for moving said platens between said spread and less spread positions and for releasably locking said platens in said less spread positions;

upper and lower, opposed, differential pressure mold means mounted on said upper and lower platens, respectively, for movement therewith between open positions and closed positions for engaging opposite sides of a thermoplastic sheet of material and differentially pressure forming an article therein;

fluid pressure operated means mounting one of said upper and lower mold means on one of said upper and lower platens, respectively, for movement relative thereto when said platens are locked in said less spread positions to incrementally move said one mold means relative to said one platen toward the other of said upper and lower mold means to tightly sandwich said sheet between said upper and lower mold means;

said fluid pressure operated means comprising a variable volume fluid pressure chamber between confronting portions of said one platen and said one mold means

wherein

a separator plate is disposed in said chamber between said confronting portions of said one platen and said one mold means, and first and second circumferentially extending seal means are disposed between, and in sealing engagement with said separator plate and each of said one platen and said one mold means respectively.