Cutting – Tool or tool with support – Joint or connection
Patent
1993-09-30
1995-11-14
Rada, Rinaldi I.
Cutting
Tool or tool with support
Joint or connection
83674, 83677, B26D 162
Patent
active
054656419
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to a knife cylinder for cross-cutting or cross-perforating a continuous web such as paper, plastic, metal, foil, fabric or the like. The knife cylinder is formed with at least one open slot for receiving a knife substantially parallel to the axis of rotation of the cylinder and includes pressure points distributed over the length of the knife for attaching the knife within the cylinder.
U.S. Pat. No. 2,341,503 discloses a sheet cutting mechanism in which a web of material travels through a gap formed between a pressure cylinder and a knife cylinder rotatable in a machine frame for cutting the web. The web loops at least in part around one of the two cylinders. Cutting knives are mounted on the knife cylinder, each knife being mounted for adjustably pre-loading the knife in a radial direction at least by relatively small amounts with respect to the knife cylinder. An adjustable wedge is utilized for this purpose together with resilient means such as a block of rubber. The use of rubber as the elastic medium and a wedge mounted on the cylinder has, however, the drawback that rubber can become hard during the service life thus altering its elasticity. And, the wedge can be only crudely adjusted so that the elasticity of the rubber is not totally utilized and the rubber block which presses the knife against the web or the backup cylinder is significantly higher than necessary so that the cutting edge of the knife is unnecessarily strained and quickly wears out. In addition, the wedge can be adjusted only when the cylinder is not rotating, a feature that renders accurate and fine adjustment of the knife more difficult.
In the knife cylinder disclosed in British Patent No. 878556, the knife blade is radially adjustable with the use of a wedge shifted with the aid of a screw. However, the shifting of the wedge to thus adjust the knife blade is possible only if the knife cylinder is idle and not rotating.
Similarly, radial adjustment of the knife blade of a knife cylinder in German Patent No. 1,264,237 is effected with the use of a turnscrew. However, such adjustment is only possible when the knife cylinder is not rotating.
U.S. Pat. No. 4,594,928, commonly owned herewith, discloses a knife cylinder which includes radially disposed pressure medium cylinders which transmit a force for bracing the knives securely within the knife cylinder.
SUMMARY OF THE INVENTION
If is therefore an object of the present invention to improve upon the prior art knife cylinders in such a manner that the radial adjustment of the knives relative to the counterpressure rotatable cylinder is simplified.
In accordance with the invention, the knife blades of the knife cylinder are located in open slots formed in the cylindrical surface portion of the cylinder, and motor means is disposed within each open slot for rotation together with the cylinder for adjusting the knife in a radial direction during rotation of the cylinder. Means is provided on the cylinder for actuating the motor means to control the radial adjustment of the knife, and stationary means is located outside the cylinder for operating the actuating means.
The knives can be radially adjusted together while the knife cylinder is rotating during a web processing operation, without having to interrupt the rotation of the knife cylinder. Thus, the web processing machine in which the knife cylinder is mounted, such as a form printing machine, need not be interrupted. Consequently, such production stoppage which would result from stopping the knife cylinder or the entire machine is avoided. In addition, the elastic springiness of the knife, to which it is subjected upon radial adjustment in particular during the short period of time when the knife becomes effective, i.e., when confronting the traveling web or the counterpressure cylinder, can also be adjusted. At the same time these influences, which start from the web to be processed on the adjustment of the respective knife, can be readily taken into consideration. Furthermor
REFERENCES:
patent: 2341503 (1944-02-01), La Bombard
patent: 3251256 (1966-05-01), McGrath
patent: 4594928 (1986-06-01), Thomas et al.
patent: 5282409 (1994-02-01), Rojas
patent: 5367936 (1994-11-01), Held et al.
Maschinenfabrik Goebel GmbH
Rada Rinaldi I.
Woods Raymond D.
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