Triple sheet thermoforming apparatus

• US 6,749,418 B2
• Filed: 07/05/2001
• Issued: 06/15/2004
• Est. Priority Date: 08/20/1998
• Status: Expired due to Fees

• Current Assignee: Nextreme LLC
• Original Assignee: Nextreme LLC
• Inventors: Muirhead, Scott A. W.
• Primary Examiner(s): Mackey, James P.
• Assistant Examiner(s): HECKENBERG JR, DONALD H
• Application Number:
  US09/898,457
• Publication Number:
  US 20020058082A1
• Time in Patent Office: 1,076 Days
• Field of Search: 425/503, 425/504, 425/515, 425/183, 425/195, 425/388, 425/405.1, 268/248, 268/545, 156/285
• US Class Current: 425/515
• CPC Class Codes: B29C 2035/0822 using IR radiation
• CPC Class Codes: B29C 2791/001 Shaping in several steps
• CPC Class Codes: B29C 2791/006 Using vacuum
• CPC Class Codes: B29C 51/10 Forming by pressure difference, e.g. vacuum
• CPC Class Codes: B29C 51/12 of articles having inserts or reinforcements
• CPC Class Codes: B29C 51/165 combined with the feeding or the shaping of the lining or the labels by injection moulding B29C45/14008, B29C45/1418
• CPC Class Codes: B29C 51/267 Two sheets being thermoformed in separate mould parts and joined together while still in the mould B29C49/0691 takes precedence
• CPC Class Codes: B29C 65/028 making use of inherent heat, i.e. the heat for the joining comes from the moulding process of one of the parts to be joined
• CPC Class Codes: B29C 65/1412 Infrared [IR] radiation
• CPC Class Codes: B29C 65/7861 In-line machines, i.e. feeding, joining and discharging are in one production line B29C65/7879, B29C65/7888 take precedence
• CPC Class Codes: B29C 65/7879 said parts to be joined moving in a closed path, e.g. a rectangular path B29C65/7888 takes precedence
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/54 Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
• CPC Class Codes: B29C 66/543 joining more than two hollow-preforms to form said hollow articles
• CPC Class Codes: B29C 66/545 one hollow-preform being placed inside the other
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/73521 of different thickness, i.e. the thickness of one of the parts to be joined being different from the thickness of the other part
• CPC Class Codes: B29C 66/8242 Pneumatic or hydraulic drives using fluid pressure directly acting on the parts to be joined B29C66/8266
• CPC Class Codes: B29C 66/82421 using an inflatable element positioned between the joining tool and a backing-up part
• CPC Class Codes: B29C 66/83221 cooperating reciprocating tools, each tool reciprocating along one axis
• CPC Class Codes: B29K 2023/065 : HDPE, i.e. high density polyethylene
• CPC Class Codes: B29L 2031/7172 : Fuel tanks, jerry cans
• CPC Class Codes: B29L 2031/7178 : Pallets
• CPC Class Codes: B65D 19/0002 : Platforms, i.e. load supporting devices without provision for handling by a forklift
• CPC Class Codes: B65D 19/0012 : forming a continuous plane contact surface
• CPC Class Codes: B65D 19/0018 : and each contact surface having a discrete foot-like shape
• CPC Class Codes: B65D 2519/00034 : Plastic
• CPC Class Codes: B65D 2519/00069 : Plastic
• CPC Class Codes: B65D 2519/00104 : Plastic
• CPC Class Codes: B65D 2519/00139 : Plastic
• CPC Class Codes: B65D 2519/00288 : made of one piece
• CPC Class Codes: B65D 2519/00293 : made of more than one piece
• CPC Class Codes: B65D 2519/00303 : Cell type, e.g. honeycomb
• CPC Class Codes: B65D 2519/00318 : made of one piece
• CPC Class Codes: B65D 2519/00323 : made of more than one piece
• CPC Class Codes: B65D 2519/00333 : contact surface having a stringer-like shape
• CPC Class Codes: B65D 2519/00338 : contact surface having a discrete foot-like shape
• CPC Class Codes: B65D 2519/00358 : Cell type, e.g. honeycomb
• CPC Class Codes: B65D 2519/00407 : on the load supporting surface
• CPC Class Codes: B65D 2519/00412 : on the base surface
• CPC Class Codes: B65D 2519/00447 : on the non-integral separating spacer
• CPC Class Codes: B65D 2519/00557 : without separate auxiliary elements
• CPC Class Codes: B65D 2519/00562 : chemical connection, e.g. glued, welded, sealed
• CPC Class Codes: B65D 2519/0094 : nestable

Abstract

A thermoforming machine for manufacturing triple sheet thermoplastic articles is disclosed. The thermoforming machine comprises three controllable ovens for heating three sheets to a heat deformable temperature, three shape giving molds for separately thermoforming each sheet in succession, and forging-like means to compress the three thermoformed sheets into a unitary article. The three sheets are thermoformed and compressed together in a form station comprising upper and lower platens. Acting with the upper platen is a mold shuttle system for moving two of three molds into position relative the thermoforming and forging-like operations of the apparatus.

Claims

1. Apparatus for differential pressure forming a single article from three heat deformable thermoplastic sheets comprising:

four work stations designated one, two, three and four positioned in spaced relation in a circular arrangement,

a frame supporting said work stations,

said work stations one, two and three including an oven for heating the thermoplastic sheets to a thermoformable temperature,

said work station four including opposed platens movable vertically between open and closed positions,

an indexing wheel rotatably supported surrounding said work stations,

said indexing wheel including four clamp frames movable with said indexing wheel into spaced relations with said four work stations respectively, and

drive means connected to said indexing wheel for rotating said indexing wheel to advance the three thermoplastic sheets secured to said clamp frames to said work stations one, two, and three for heating and to said work station four for molding each of the three heated thermoplastic sheets into a preselected configuration and fusing the molded sheets together in overlying relation to form a unitary thermoplastic article.

2. Apparatus for thermoform molding three thermoplastic sheets to form a triple sheet molded article comprising:

a work station,

three thermoforming molds designated one, two, and three supported on said work station for molding three thermoplastic sheets respectively, each of said three thermoforming molds having an oven for heating said three thermoplastic sheets to a thermoformable temperature,

a slide assembly mounted on said work station for independently moving two molds in overlying relation into and out of a fixed position on said work station for molding the thermoplastic sheets,

a first platen and a second platen positioned in overlying spaced relation on said work station for independent movement between open and closed positions,

said first platen receiving mold one for movement into compressed relation with sheet one,

said second platen slidably receiving molds two and three in succession for movement into compressed relation with sheets two and three in succession respectively,

said first platen with said mold one positioned thereon movable to a closed position into contact with sheet one to mold sheet one into a preselected configuration,

said second platen with said mold two positioned thereon movable to a closed position into contact with sheet two to mold sheet two into a preselected configuration,

said first and second platen with molded sheets one and two thereon movable into compressed force together molded sheets one and two to form a twin sheet molded sub-assembly,

said first retaining the twin sheet molded sub-assembly with said second platen slidably exchanging mold two with mold three,

said second platen with said mold three positioned thereon movable to a closed position into contact with sheet three to mold sheet three into a preselected configuration, and

said first platen carrying the twin sheet molded sub-assembly into compressed relation with said second platen carrying the molded sheet three to fuse molded sheet three to the twin sheet molded article to form a triple sheet molded article.

3. A thermoforming machine comprising:

a machine frame;

three ovens spaced upon the machine frame;

at least three clamp frames operable to convey three sheets in succession through the three ovens and a form station;

the form station has a lower platen and an upper platen;

the lower platen supports a first mold;

the upper platen is connected to a mold shuttle system, the mold shuttle system holds a second mold and a third mold and is operable to alternately deliver the second mold and the third mold into a supporting position upon the second platen;

the lower platen is operable to carry the first mold from an open position to a first closed position to thermoform a first sheet, repeatedly carry the thermoformed first sheet to the open position, compress the first mold against the second mold at a second closed position, and compress the first mold against the third mold at a third closed position; and

the upper platen is operable from an open position to interface with the mold shuttle system, to receive and carry the second mold to a first closed position to thermoform a second sheet, to receive and carry the third mold to a second closed position to thermoform a third sheet, and remain in the first and second closed positions when the lower platen compresses the first mold against the second mold in the first closed position and the third mold in the second closed position.

4. The thermoforming machine of claim 3 further comprising:

a bolster plate beneath the first mold;

between the bolster plate and the lower platen a plurality of vertically acting actuators; and

a controller means causing the actuators to incrementally move the bolster plate vertically compressing the first mold against the second mold in the first closed position and the mold in the second closed position.

5. A thermoforming apparatus comprising:

a frame;

at least three spaced apart ovens for heating thermoplastic sheets to a thermoformable temperature;

a lower platen supported for vertical movement upon the frame;

a first mold mounted on the lower platen;

an upper platen supported for vertical movement upon the frame above the lower platen;

a mold shuttle system supported upon the frame acting with the upper platen;

a second and third mold mounted for horizontal movement on the mold shuttle system; and

an controllable actuation means selectively moving the second or third mold horizontally on the mold shuttle system into an engaged position upon the upper platen for vertical movement thereon,

wherein the first mold, second mold, and third mold are operable to fuse said thermoplastic sheets received from said at least three spaced apart ovens.

6. The triple sheet form station of claim 5 further comprising:

a plurality of upper gear posts supported upon the frame extending vertically adjacent the upper platen;

engaging the upper gear posts upper platen gears precisely driven by at least one first motor for selective vertical movement of the upper platen;

a plurality of gear posts supported upon the frame extending vertically adjacent the lower platen below the upper gear posts;

engaging the lower gear posts lower platen gears precisely driven by at least one second motor for selective vertical movement of the lower platen below the upper platen; and

a controller means for selectively controlling the first and second motors for independent and simultaneous precise movement of the upper and lower platens upon the frame.

7. A thermoform tooling apparatus comprising:

a first oven operable to heat a first thermoplastic sheet;

a second oven being spaced apart from said first oven, said second oven operable to heat a second thermoplastic sheet;

a third oven being spaced apart from said first and second ovens, said third oven operable to heat a third thermoplastic sheet;

a work station being spaced apart from said first, second, and third ovens, said work station having a first platen and a second platen movable relative to each other between a first position and a second position;

a drive assembly supporting each of said first, second, and third thermoplastic sheets, said drive assembly operable to position said first, second, and third thermoplastic sheets within said first, second, and third ovens, respectively, and further operable to deliver said first, second, and third thermoplastic sheets to said work station for fusing said first, second, and third thermoplastic sheets together.

8. The thermoform tooling apparatus according to claim 7 wherein said drive assembly comprises:

an indexing wheel having a plurality of frames for supporting said first, second, and third thermoplastic sheets; and

a drive device operably coupled with said indexing wheel for driving said indexing wheel.

9. The thermoform tooling apparatus according to claim 7, further comprising:

a first mold mounted on the first platen;

a mold shuttle system operably coupled with the second platen;

a second and third mold mounted for horizontal movement on the mold shuttle system; and

an controllable actuation means selectively moving the second or third mold horizontally on the mold shuttle system into an engaged position upon the second platen for vertical movement thereon.