Patent Application
20070074634
The invention relates to an improved hydraulic clamp for releasably connecting a cylindrical printing head to a printing shaft in a beverage container decorating machine.
A known beverage container decorator machine is disclosed, for example, in U.S. Pat. No. 5,819,648.
As best seen in
A conventional hydraulic clamp suitable for retaining the printing head on the printing shaft of the decorator is disclosed in PCT international application WO98/46896. The disclosures of the foregoing publications are incorporated by reference.
Advantages of the use of this type of hydraulic clamp in the locking mechanism include easy removal and assembly of the plate cylinder for labeling changes. The clamp provides zero clearance after locking the hydraulic hub, which results in improved printing quality. Earlier devices required clearance in order to be assembled onto the shaft.
For pressurizing the hydraulic chamber to clamp the device in WO '896 onto a shaft, the device requires either a plurality of axial pressure screws mounted in a complicated collar arrangement, or a single pressure screw oriented circumferentially of the device. In the first case, the removal operation is slow and inconvenient. In the second case, the pressure screw will not be easily and safely accessible in the environment of the typical container decorator machine.
Responding to these drawbacks of the prior art, the present invention, provides an improved hydraulic clamp, particularly for releasably retaining a printing head on a printing shaft in a beverage container decorating machine.
The improvements may include a hydraulic clamp with a single, large, axially arranged pressure cylinder; a correspondingly enlarged axially arranged screw for actuating the hydraulic cylinder; a flange on the screw for stopping the screw in one direction; and a stop plate for stopping the screw in the other direction. With these features, the hydraulic clamp can be easily released from the shaft by a single operation of the pressure screw, which can be carried out from a location safely spaced away from the end of the shaft in the axial direction. Thus, the invention provides a clamp with quicker release and greater safety than with the known clamps.
The advantages of the invention include the use of a single screw, which provides quicker release than the axial clamp of WO '896, which has multiple, smaller screws; the flange; and the stop plate.
The activating screw can be mathematically engineered to perform at least three functions:
According to an aspect of the invention, a hydraulic clamp for being mounted on a shaft may comprise a clamp body; an aperture in said clamp body for receiving said shaft, said aperture extending in an axial direction of said clamp body from a first end to a second end thereof; a recess formed in said clamp body and substantially surrounding said aperture, for receiving a pressure medium; said clamp body having at said first end thereof a pressure generator communicating with said recess for pressurizing said pressure medium and thereby deforming said recess sufficiently to secure said clamp to said shaft; wherein said pressure medium is pressurized by an axial movement of said pressure generator toward said second end; and wherein said hydraulic clamp comprises a first structure which limits said axial movement of said pressure generator toward said second end.
According to another aspect of the invention, the hydraulic clamp may comprise a clamp body; an aperture in said clamp body for receiving said shaft, said aperture extending in an axial direction of said clamp body from a first end to a second end thereof; a recess formed in said clamp body and substantially surrounding said aperture, for receiving a pressure medium; said clamp body having at said first end thereof a single pressure cylinder communicating with said recess for pressurizing said pressure medium and thereby deforming said recess sufficiently to secure said clamp to said shaft; said single pressure cylinder having a corresponding single piston arranged for axial movement toward said second end for pressurizing said pressure medium.
In other aspects, the invention is not limited to a single piston and cylinder.
The piston and cylinder may be threaded such that rotation of said piston drives said piston into said cylinder toward said second end to pressurize said pressure medium.
The piston may comprise a flange, which is disposed on said piston for engaging said clamp body and thereby limiting axial movement of said piston toward said second end.
The clamp body may comprise a stop, which is disposed for engaging said piston and thereby limiting axial movement of said piston away from said second end. The stop may have an aperture arranged axially of said piston, said aperture permitting a tool to access said piston by being inserted generally in said axial direction.
Other features and advantages of the present invention will become apparent from the following description of embodiments of the invention which refers to the accompanying drawings.
Referring now to
The hydraulic hub 15 has a circumferential annular recess 36 defined by at least one expandable outer wall 37 and an expandable inner wall 38. When the recess 36 is pressurized, the inner wall 38 clamps onto the shaft 10 and the outer wall 37 clamps against the inside diameter of the printing cylinder at the same time. The hydraulic hub 15 further has a single, large-diameter pressure screw 30 which moves a piston 32 for compressing hydraulic fluid in a hydraulic chamber or recess 33. The hydraulic chamber or recess 33 communicates via a passage 34 with the circumferential chamber or recess 36.
In contrast to the device in WO '896, which requires either a plurality of axial screws mounted in a complicated collar arrangement, or a single screw mounted circumferentially, the present invention requires only a single, axially arranged screw 30 for pressurizing the hydraulic chamber or recess 36. Therefore, the hydraulic clamp 12 can be more easily released from the shaft 10 by a single unscrewing operation, which can be carried out with the operator at a location safely spaced away from the end of the shaft in the axial direction.
In addition, the pressure screw 30 has an enlarged flange 40 on its outside end. The combination of the screw 30 and the flange 40 limits the travel of the screw and piston 32 into the chamber 33 and thus prevents potential overpressure or binding or jamming in the chamber 33.
Further, mounted on the outer hub 25 is a stop plate 45. The stop plate 45 has a hole 47 for permitting insertion of a tool for actuating the pressure screw 30. The stop plate 45 also prevents the pressure screw 30 from being unscrewed too far from the chamber 32 and potentially lost.
In combination, the flange 40 and the stop plate 45 limit the travel of the screw 30 both into and out of the chamber 33. With these limits being automatically provided, the operator is able to move the screw 30 either into or out of the chamber 33 with a minimum of thought and judgment being required, and therefore rapidly and conveniently.
Referring now to
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. Therefore, the present invention is not limited by the specific disclosure herein.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US03/32608 | 10/15/2003 | WO | 12/8/2006 |
| Number | Date | Country | |
|---|---|---|---|
| 60420673 | Oct 2002 | US |
