Mandrel Used For Digital Printing On Can Members

• US 20080282913A1
• Filed: 11/03/2006
• Published: 11/20/2008
• Est. Priority Date: 11/03/2005
• Status: Active Grant

• Current Assignee: Ball Beverage Packaging Europe Limited (Ball Corporation)
• Original Assignee: Ball Packaging Europe GmbH & Company KG
• Inventors: Noll, Werner, Thate, Helmut
• Granted Patent: US 8,708,271 B2
• Time in Patent Office: Days
• US Class Current: 101/39
• CPC Class Codes: B41F 17/002 Supports of workpieces in machines for printing on hollow articles

Abstract

There is proposed a clamping mandrel for a rotationally symmetrical hollow body in the form of a beverage can integrally comprising a body portion and a bottom. Accurate coupling and precise control of the movement of the mandrel is to be transmitted to the hollow body. For that purpose there are provided a plurality of clamping segments forming an outwardly facing cylindrical clamping surface for engaging an inside surface of the hollow body. The clamping segments are radially movably guided. A force-transmission device arranged in the interior of the clamping mandrel is provided for synchronous control of the radial movement of the clamping segments. That provides for controlled precision movement of a hollow body clamped by the clamping device.

Claims

1. A clamping mandrel for a rotationally symmetrical hollow body, in particular a beverage can integrally comprising a body portion and a bottom, comprising:

a plurality of clamping segments which combined form an outwardly facing cylindrical clamping surface for engaging an inside surface of the hollow body;

wherein the clamping elements are guided synchronously radially movably;

comprising a force-transmission device arranged in the interior of the clamping mandrel for controlling a radial movement of the clamping segments;

to facilitate a controlled precision movement of the clamped hollow body.

2. The clamping mandrel according to claim 1, wherein the force-transmission device is actuable for the clamping action by a reduced pressure and for the release action by an increased pressure.

3. The clamping mandrel according to claim 2, wherein the two different pressure forces serving for control are at the same time respectively operative for mounting the hollow body on the clamping mandrel and for expelling the hollow body from the clamping mandrel.

4. The clamping mandrel according to claim 1, wherein there is provided a main body, having a shaft drivable in rotation with an axial bore opening in the free end face of the shaft and two end wall elements fixedly arranged at an axial spacing on the shaft, and wherein one of the end wall elements which in operation of the mandrel faces towards the bottom of the hollow body has an axial outside surface which terminates substantially flush with the end face of the shaft.

5. The clamping mandrel according to claim 1, wherein the force-transmission device has a control portion which is axially displaceably guided on a drivable shaft.

6. The clamping mandrel according to claim 5, wherein the control portion is fixedly connected with one of its ends to a disc-shaped wall which is axially displaceably guided in the force-transmission device as the main body, wherein the disc-shaped wall can be acted upon by at least one of compressed air or a pressure in the axial bore.

7. The clamping mandrel according to claim 6, wherein the disc-shaped wall forms a movable boundary wall of a chamber which accommodates increased pressure or reduced pressure and which is defined on the other hand by an end wall element which is enlarged in a chamber-like configuration.

8. The clamping mandrel according to claim 2, wherein the shaft is supported outside the clamping mandrel together with a multiplicity of identical mandrels in a carrier head rotatable in indexing steps and at the end of each shaft is provided with a dedicated, controllable drive which operates stepwise, and each of the axial bores can be operably connected to a source for higher or lower pressure.

9. The clamping mandrel according to claim 5, wherein the control portion is axially displaceably guided on the shaft by way of sliding portions.

10. The clamping mandrel according to claim 5, wherein each clamping segment on its interior has an inside surface which is conical in the axial direction or is fixedly connected to a clamping portion having such an inside surface, wherein the conical inside surface extends parallel to the conical outside surface of the control portion but spaced therefrom.

17. The clamping mandrel according to claim 1, wherein the force-transmission device has a control device which is actuated by pneumatic control.

18. The clamping mandrel according to claim 4, wherein at least the end face of the shaft is inwardly curved, and adapted to a shape of the bottom of the hollow body.

19. The clamping mandrel according to claim 7, wherein the chamber is connected to the axial bore in the shaft by way of at least one substantially radial bore in the shaft.

23. The clamping mandrel according to claim 1, wherein a control portion of the force-transmission device is axially displaceably guided on the drivable shaft and an outer peripheral surface of the control portion extends conically in the axial direction in order to produce a corresponding radial synchronous displacement movement of all clamping segments in dependence on a relative axial movement of the control portion on the shaft, whereby the axial movement is converted into a radial displacement.

24. The clamping mandrel according to claim 23, wherein the control portion is rotationally symmetrical.

25. The clamping mandrel according to claim 5, wherein the control portion is operably interconnected with one of its ends to a disc-shaped wall which is axially displaceably guided in the force-transmission device as the main body, wherein the disc-shaped wall can be acted upon with reduced pressure, controlled by a bottom of the hollow body terminating flush at an end face of the shaft.

26. The clamping mandrel according to claim 1, wherein a control portion is operably interconnected with one of its ends to a disc-shaped wall which is axially displaceably guided in the force-transmission device as the main body.

27. The clamping mandrel according to claim 5, wherein each clamping segment is coupled in the region of a conical inside surface to slidingly movable sliding portions, wherein the sliding portions are slidingly movable either with respect to the conical outside surface or with respect to the conical inside surface and are fixedly connected to the respective other surface.

11. A method of location-accurate positioning and controlled precision movement of rotationally symmetrical hollow bodies, in particular integral cans comprising a body portion and a bottom, wherein a respective hollow body is engaged at its rotationally symmetrical inside surface substantially over its entire surface area in particular by synchronously applied associated clamping surfaces with radially acting clamping forces and/or is released disengaged synchronously therefrom.

28. The method according to claim 11, wherein the radially acting clamping forces are released or/and applied by an increased pressure caused by air flow or/and a reduced pressure.

12. A method of location-accurate positioning and controlled precision movement of rotationally symmetrical hollow bodies formed integrally from a body portion and a bottom, by means of a respective rotatable clamping mandrel for each of the hollow bodies, comprising:

fitting the respective hollow body on to the clamping mandrel by way of reduced pressure and positioned axially thereon;

providing the hollow body is braced by a pressure force caused by the same reduced pressure and acting radially from the inside outwardly to afford a motion unit with the clamping mandrel, which pressure force is applied by clamping segments moved outwardly synchronously by the same reduced pressure.

13. The method according to claim 12, wherein the motion unit of the clamping mandrel and the hollow body is released by means of compressed air.

14. The method of claim 12, wherein a control portion of the force-transmission device is loaded with a return device which applies an axial force axially rearwardly away from a front end of the clamping mandrel.

15. The method or clamping mandrel according to claim 14, wherein the return device is a spring which is preferably biased in the retracted rest position of the control portion.

16. The method or clamping mandrel according to claim 14, wherein the control portion is returned by the axial force loading after a respective removal of a hollow body from the clamping mandrel into a neutral rest position which is so positioned that even hollow bodies which fluctuate in diameter can be axially received by the clamping mandrel in the rest position of the control portion.

29. The method according to claim 13, wherein the hollow body is axially removed from the clamping mandrel with the same compressed air.

20. A clamping device for a rotationally symmetrical hollow body which is closed at an end, comprising:

a plurality of radially movably guided clamping segments forming an outwardly facing cylindrical clamping surface for engaging an inside surface of the hollow body;

a force-transmission device which is arranged in the clamping device and which has a control portion axially displaceably guided on a drivable shaft of the clamping device and having an outer peripheral surface which is conical in the axial direction for converting an axial movement of the control portion on the shaft into corresponding synchronous radial displacement movements of the clamping segments which are provided with corresponding conical inside surfaces, wherein all clamping segments are moved synchronously; and

wherein the control portion is operably interconnected with one of its end faces to a disc-shaped wall, guided displaceably axially on the shaft, of a pressure chamber arranged in the clamping mandrel, which pressure chamber can be controlledly connected to a compressed air source or a reduced pressure source.

21. A method or clamping mandrel according to claim 21, wherein it is suitable for clamping integral cans comprising a body portion and a bottom.

22. A method of location-accurate positioning and controlled precision movement of rotationally symmetrical hollow bodies formed from a body portion and an integrally adjoining bottom, by means of a controlledly moved clamping mandrel for each of the hollow bodies, comprising:

fitting the respective hollow body on to the clamping mandrel by way of reduced pressure and positioned axially thereon; and

providing the hollow body is braced by the same reduced pressure synchronously under a pressure force acting radially from the inside outwardly to afford a motion unit with the clamping mandrel.

30. The method of claim 22, wherein the controlled precision movement is preferably stepwise.