Thermoshaping machine

Abstract

A press has a frame including guides extending in a predetermined direction and a pair of tool-halves mounted on the frame and are movable on the guides in the direction toward and away from each other. Two knee-lever linkages symmetrically spacedly flanking each tool half with respect to a center plane substantially parallel to the direction, each coupled to the respective tool half and to the frame, and operable to shift the tool halves in the direction. Respective reversible, rotary drives each carry an eccentric output connected to respective drive links extending to the linkages. A controller connected to the drives rotates the eccentrics oppositely in respective first senses to press the one half in the direction against the other half and thereafter to pull the one half in the direction away from the other half with the two linkages never extending into a central region of the machine.

Description

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a partly diagrammatic side view of a thermoshaping machine according to the invention;

FIG. 2 is a perspective view of the lower part of the emachine;

FIG. 3 is a graph illustrating operation of the machine according to the invention; and

FIGS. 4 a-4c, and 4d-4f are side views illustrating the machine according to the invention in succeeding cycles.

Claims

1. A press comprising: a frame including guides extending in a predetermined direction;a pair of tool halves mounted on the frame, one of the halves being movable on the guides in the direction toward and away from the other of the halves;two knee-lever linkages symmetrically spacedly flanking the one tool half with respect to a center plane substantially parallel to the direction, coupled to the one half and to the frame, and operable to shift the one tool half in the direction;respective reversible rotary drives each carrying an eccentric output;respective drive links extending between the eccentric outputs and the linkages;control means connected to the drives for rotating the eccentrics oppositely in respective first senses to press the one half in the direction against the other half and thereafter to pull the one half in the direction away from the other half with the two linkages never extending into a central region of the machine at the plane.

2. The press defined in claim 1 wherein the knee linkages each include two levers having inner ends pivoted together and outer ends, the outer end of one of the levers of each linkage being pivoted on the frame and the outer end of the other of the levers of each linkage being pivoted on the one tool half.

3. The press defined in claim 2 wherein the linkages move between inner positions with the respective levers extending generally parallel to the plane and the one half pressed against the other half and outer positions with the respective levers extending at an angle of substantially less than 180° to each other.

4. The press defined in claim 3 wherein the drive links are pivoted at the inner ends of the levers of the respective linkages.

5. The press defined in claim 1 wherein each drive includes a motor and a transmission.

6. The press defined in claim 1, further comprising means for stepping a sheet workpiece perpendicular to the direction between the tool halves.

7. The press defined in claim 1, further comprising two second knee-lever linkages symmetrically spacedly flanking the other tool half with respect to the center plane, coupled to the other half and to the frame, and operable to shift the other tool half in the direction;respective second reversible rotary drives each carrying an eccentric output;a respective second drive links extending between the eccentric outputs and the second linkages, the control means being connected to the second drives to operate same synchronously with the first-mentioned drives.

8. The press defined in claim 7 wherein the first and second drives are mechanically coupled to each other.

9. The press defined in claim 7 wherein the first and second drives are electronically coupled to each other.

10. The press defined in claim 7 wherein each of the drives is provided with a respective housing mounted on the frame.

11. The press defined in claim 1 wherein the drive includes a reversible servomotor.

12. The press defined in claim 1 wherein the drives and links also symmetrically flank the plane.

13. A method of operating a thermoshaping press having: a frame including guides extending in a predetermined direction;a pair of tool halves mounted on the frame, one of the halves being movable on the guides in the direction toward and away from the other of the halves;two knee-lever linkages symmetrically spacedly flanking the one tool half with respect to a center plane substantially parallel to the direction, coupled to the one half and to the frame, and operable to shift the one tool half in the direction;respective reversible rotary drives each carrying an eccentric output; andrespective drive links extending between the eccentric outputs and the linkages

14. The method defined in claim 13 wherein the eccentrics are rotated at such speeds that, despite the different angular travels between the open and closed positions, the travel time is the same for the opening and closing movements.