Cutting – Processes – With subsequent handling
Patent
1996-08-07
1998-06-23
Jones, Eugenia
Cutting
Processes
With subsequent handling
83 50, 83 55, 83 91, 83112, 83123, 83569, B26D 718, B26F 140
Patent
active
057689636
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method and an apparatus for punching a stack of sheet-like articles, especially labels.
In the punching of labels by the method known as penetration punching, it is generally known that the stack of precut labels is pressed in one stroke through a punching knife. The punched labels are automatically pushed through the punching knife by the subsequent stack. When the blade of the punching knife penetrates into the precut labels, the problem arises in this punching method that, in particular, the upper sheets of the stack bend, which results in inaccuracies in the form of a type of "cushion formation" with punching offsets within the stack.
In order to eliminate these disadvantages, it is proposed in DE-A-4,013,071 that a pressure ram be pressed against the stack on the opposite side of the table top that serves as a punching ram, in order to guide the stack through the punching knife in a vertical pressure position. In this penetration punching method, the stack is pushed through the punching knife by a lifting apparatus in the table top, designed as a plunger, together with the pressure ram generating the counter-pressure. The table top is then lowered with the lifting apparatus and the pressure ram is raised. The ready-punched stack is then passed to a bundling station by a horizontally displaceable transport clamp.
Although this apparatus permits a precise punching of the labels, the working speed is considerably slowed by the various additional interventions with the pressure ram and the lifting apparatus. In particular, the lifting apparatus initially has to be retracted before the table top can again be brought into its initial position and receive a new stack.
The object of the present invention is to provide a stamping method which guarantees both a high stamping quality and a high working speed of the stamping apparatus.
This object is achieved by a stamping method and the stamping apparatus.
The most important advantage of this invention is that a new stack of sheet-like articles, especially labels, can again be presented to the punching ram while, at the same time, the ready-punched stack of labels is still being removed from the punching knife. Deformations and/or indentations in the punched labels which arise as a result of the penetration of the punched stack by a ram, as in the method using the apparatus according to DE-A-4,013,071, are also avoided in a particularly advantageous manner. Since the counter-pressure plunger both exerts a counter-pressure during punching and is used to push back the punched stack, the machinery cost of the apparatus according to the invention is likewise lower.
Further advantages of the invention are likewise apparent from the subclaims and from the description which follows. In the description, the invention is explained in detail with reference to an example shown diagrammatically in the drawings.
In the drawings:
FIG. 1 shows a lateral view of a label punching apparatus,
FIG. 2 shows an enlarged representation of the label punching apparatus according to FIG. 1,
FIG. 3 shows a top view, in an enlarged representation, of the label punching apparatus according to FIG. 1,
FIGS. 4a-4e snow stages of the punching method with the label punching apparatus in the lateral view, and
FIGS. 5a-5c show stages of the punching method with the label punching apparatus in a top view.
In the figures, the same reference symbols are used for the same elements on each occasion, so that an initial statement relating to a particular element is valid for all figures.
In FIGS. 1, 2 and 3, a label punching apparatus 1 is shown entirely diagrammatically, having in essence a machine frame 2 with a punching ram 3, a punching knife 4 and a counter-pressure plunger 5. The punching ram 3 is reciprocally movable by means of a hydraulically actuated piston (not seen here) in a plunger cylinder 6. The punching material 7, a stack of sheet-like articles such as sheets of paper, thin paperboard or the like, lies against the punching ram 3. The punching knife 4 is fixed
REFERENCES:
patent: 2483735 (1949-10-01), Noell
patent: 3290977 (1966-12-01), Brestel et al.
patent: 3505918 (1970-04-01), Schneider
patent: 3546990 (1970-12-01), Schneider
patent: 3741057 (1973-06-01), Maschinot
patent: 5183247 (1993-02-01), Blumer
Blumer Maschinenbau AG
Jones Eugenia
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