Thermoforming Machine Having Toggle Differential Load Mechanism and Method

• US 20190329479A1
• Filed: 12/10/2018
• Published: 10/31/2019
• Est. Priority Date: 04/25/2018
• Status: Active Application

• Current Assignee: Irwin Research and Development, Inc.
• Original Assignee: Irwin Research and Development, Inc.
• Inventors: Vantrease, Dale L., Irwin, Jere F.
• Granted Patent: US 11,865,764 B2
• Time in Patent Office: Days
• CPC Class Codes: B29C 51/082 by shaping between complementary mould parts
• CPC Class Codes: B29C 51/20 having movable moulds or mould parts
• CPC Class Codes: B29C 51/38 Opening, closing or clamping means
• CPC Class Codes: B29C 51/46 Measuring, controlling or regulating

Abstract

A thermoforming apparatus is provided having a frame, a pair of platens, and a platen drive assembly. The platens are carried by the frame on opposite sides of a sheet line each configured to carry a respective die. One platen has a proximal die surface adjacent the sheet line and a rear surface distal the sheet line. The platen drive assembly is interposed between the frame and the one platen and has at least one reciprocating kinematic linkage and a drive motor configured to reciprocate the one platen to and fro relative to another platen. The kinematic linkage has a plurality of links interconnected pivotally together with respective rotation joints and interposed between the frame and the one platen. An outboard-most rotation joint is provided proximate one end of the frame and an inboard-most rotation joint intermediate the rear surface and the proximal die surface. A method is also provided.

Claims

1. A thermoforming apparatus, comprising:

a frame encompassing a sheet line;

a pair of platens carried by the frame on opposite sides of the sheet line each configured to carry a respective die, one platen having a proximal die surface adjacent the sheet line and a rear surface distal the sheet line; and

a platen drive assembly interposed between the frame and the one platen having at least one reciprocating kinematic linkage and a drive motor configured to reciprocate the one platen to and fro relative to another platen, the kinematic linkage having a plurality of links interconnected pivotally together with respective rotation joints and interposed between the frame and the one platen, an outboard-most rotation joint proximate one end of the frame and an inboard-most rotation joint intermediate the rear surface and the proximal die surface.

2. The thermoforming apparatus of claim 1, wherein the platen drive assembly includes a pair of toggle shafts each with a pair of spaced-apart toggle arms each coupled in rotation at one end with a drive arm and at a distal end with a drive connection adjacent a distal portion of the platen.

3. The thermoforming apparatus of claim 2, wherein the platen drive assembly further comprises a pair of toggle bearings provided on opposed ends of each toggle shaft, each bearing assembly supported proximate a distal end of the frame.

4. The thermoforming apparatus of claim 3, wherein the distal end comprises one of a top end and a bottom end of the frame.

5. The thermoforming apparatus of claim 1, wherein the another platen has a proximal die surface adjacent the sheet line and a rear surface distal the sheet line.

6. The thermoforming apparatus of claim 5, wherein the platen drive assembly is interposed between the frame and the another platen having another at least one reciprocating kinematic linkage, the drive motor configured to reciprocate the another platen to and fro relative to the one platen.

7. The thermoforming apparatus of claim 6, wherein the another at least one kinematic linkage is configured to have a plurality of links interconnected pivotally together with respective rotation joints and interposed between the frame and the one platen, an outboard-most rotation joint proximate one end of the frame and an inboard-most rotation joint intermediate the rear surface and the proximal die surface.

8. The thermoforming apparatus of claim 1, wherein the one at least one kinematic linkage and the another at least one kinematic linkage each comprises a pair of each having a pair of toggle shafts, drive linkages, a connecting linkage for coupling together the pair of drive linkages, and the drive kinematic linkage coupled to drive the pair of kinematic linkages and platens via the connecting link for reciprocation to and fro.

9. A thermoforming apparatus, comprising:

a frame having opposed ends disposed on opposite sides of a sheet line;

a pair of opposed platens carried by the frame each configured to carry a die, one die configured to engage an opposed face of another die across a heated sheet of thermoformable material provided on the sheet line, one platen having a front die surface proximate the sheet line and a rear surface proximate the terminal end; and

a platen drive assembly interposed between the frame and the one platen to reciprocate the one platen toward and away from another platen and having at least one reciprocating kinematic linkage and a drive motor, the kinematic linkage having a plurality of links interconnected pivotally together with respective rotation joints and interposed between the frame and the one platen, an outboard-most rotation joint proximate one end of the frame and an inboard-most rotation joint inboard of the rear surface and proximate the front die surface.

10. The thermoforming apparatus of claim 9, wherein the kinematic linkage comprises a toggle shaft and a drive link pivotally coupled to a drive arm of the toggle shaft.

11. The thermoforming apparatus of claim 10, wherein the kinematic linkage further comprises a drive kinematic linkage interposed between the drive motor and the toggle shaft.

12. The thermoforming apparatus of claim 11, further comprising a pair of toggle shafts each having a pair of drive arms spaced apart across the one platen, each toggle shafted spaced perpendicularly across the one platen relative to one another, and each having a pair of drive links coupled along a side of the one platen intermediate a front surface and a rear surface of the one platen.

13. The thermoforming apparatus of claim 12, wherein the one platen and the another platen are each supported for reciprocation by the frame together and apart by respective kinematic linkages, each having a pair of toggle shafts, drive linkages, a connecting linkage for coupling together the pair of drive linkages, and the drive kinematic linkage coupled to drive the pair of kinematic linkages and platens via the connecting link for reciprocation to and fro.

14. The thermoforming apparatus of claim 9, wherein the one platen has at least one side face extending between the front die surface and the rear surface, the outboard-most rotation joint affixed to one side face.

15. The thermoforming apparatus of claim 14, wherein the at least one side face is a rectangular array of four side faces.

16. The thermoforming apparatus of claim 9, wherein the drive kinematic linkage comprises a toggle shaft and a pair of spaced-apart toggles.

17. The thermoforming apparatus of claim 16, wherein the drive kinematic linkage further comprises a pair of toggle links each affixed pivotally to a respective one of the toggles at a first end and to a side pivot mount on opposed sides of the first platen.

18. A method of maximizing die clearance between platens for a given height thermoforming frame, comprising:

providing a frame, a drive assembly, a kinematic linkage, and a pair of opposed platens, at least one of the platens supported for reciprocation by the frame toward and away from another of the platens;

supporting an outboard-most end of the kinematic linkage proximate one end of the frame via an outboard-most rotation joint; and

driving the at least one platen with the kinematic linkage pivotally affixed to the one platen at an inboard-most rotation joint inboard of a rear surface and proximate a front die surface of the one platen from a closed position to a maximally open position.

19. The method of claim 18, wherein the frame has a maximum dimension perpendicular to a sheet line through the frame and a die-open dimension when the one platen is driven to the maximally open position from a die shut height position.

20. The method of claim 18, wherein the outboard-most rotation joint of the kinematic linkage corresponds with a maximal position of reciprocation apart between the pair of opposed platens extending perpendicular to a sheet line path between the pair of opposed platens.