Material or article handling – Apparatus for moving intersupporting articles into – within,... – Stack forming apparatus
Reexamination Certificate
1999-02-09
2001-06-05
Fischetti, Joseph A. (Department: 3652)
Material or article handling
Apparatus for moving intersupporting articles into, within,...
Stack forming apparatus
C414S794900, C414S795200, C414S027000, C425S289000
Reexamination Certificate
active
06241457
ABSTRACT:
SPECIFICATION
1. Field of the Invention
Our present invention relates to a stacking apparatus for a thermoforming machine which comprises a fixed upper-forming die, a movable lower-forming die between which a foil can be disposed, an intermittent foil transport arrangement and a heating arrangement whereby articles such as cups and covers can be deep-drawn from the foil in the forming dies and, in particular, wherein the lower-forming die can operationally be raised and lowered and/or swung out of a position in which it is juxtaposed with the upper die to enable the article formed from the thermoplastic synthetic resin to be removed and stacked. More particularly, the invention relates to a stacking apparatus for the purposes described which can be selectively used for the stacking of cup-like and cover-like articles produced in a thermoforming machine.
2. Background of the Invention
A thermoforming machine of the type described has been illustrated in German patent document DE-C 233 46 628. Such machines can have forming dies which can be relatively moved toward one another and apart to produce plastic articles such as margarine containers, beverage cups, container covers, trays and the like from a thermoplastic synthetic resin foil and from composite foils.
In the machine, in a closed position of the upper and lower-forming dies, the articles are shaped and then punched from the foil and transported in the open position of the forming dies into a stacking unit. The upper-forming die of such a thermoforming machine is mounted on a rigid traverse member while the lower-forming die is fixed on a forming table which can be vertically disposed and is also swingable relative to the upper-forming die. The swingability of the forming table is ensured by providing the forming table with trunnions whose bearings are guided in respective vertical guides. The forming table drive utilizes a cam follower which is coupled to the forming table by a lever linkage and which rides on a cam disk rotatable with a main shaft of the apparatus.
In the stacking operation, to ensure that the articles will not interfere with the foil transport or vice versa, comparatively large pivoting angles between about 45° and 90° and typically of around 80°, must be used. The ejected articles must be collected on a stacking plate which is moved toward the lower-forming die to avoid the danger that the article will have excessive free fall gravitationally and fail to meet the opening provided in the stacking plate or become damaged. An alternative arrangement which involves providing a lower stacking plate, has also not been successful since the article may change in position along the way to the stacking plate. Finally an alternative in which the article is picked up by suction at the ejector has the drawback that it complicates the construction of the ejector and requires a relatively expensive vacuum system which might otherwise not be required.
OBJECTS OF THE INVENTION
It is, therefore, the principal object of the present invention to provide an improved stacking apparatus for a thermoforming machine, especially of the type described, which is free from the drawbacks mentioned and can operate with a minimum danger of alteration in the orientation of the articles produced and which does not require a vacuum unit.
Another object of this invention is to provide an improved stacking system for a thermoforming machine which affords better cooperation with the thermoforming machine than earlier systems.
It is also an essential object of the invention to provide a stacking apparatus for a thermoforming machine which can be varied to accommodate thermoformed articles of a variety of geometries, like cups, trays, covers, shells or the like and which also is of simple construction, high reliability and operable at high production rates.
SUMMARY OF THE INVENTION
These objects and others which will become apparent hereinafter are attained, in accordance with the invention in a stacking apparatus for a thermoforming machine having an intermittent foil transport, a preferably fixed upper-forming die, and a lower-forming die which is preferably swingable out of alignment with the upper-forming die and from the forming position in which the dies are aligned with one another for producing selectively a series of deep-drawn, cup-like articles, hereinafter referred to as cups, and cover-like articles, hereinafter referred to broadly as covers. According to the invention, the stacking apparatus comprises:
a stacking-apparatus support;
a lower stacking plate on the support for receiving deep-drawn articles produced by the thermoforming machine;
an upper stacking plate adapted to be juxtaposed with the lower stacking plate and complementary thereto for receiving deep-drawn articles from the lower stacking plate and for retaining a column of the articles;
a pivot arm carrying the upper stacking plate, the upper stacking plate being raisable and lowerable on the pivot arm;
a carriage to which the pivot arm is articulated for swingable movement about an arm pivot, the carriage having guide rollers;
a guide bar swingably mounted at a horizontal pivot axis on the support and engaged by the rollers for guiding the carriage therealong whereby a column of the articles on the upper stacking plate is swingable from a position wherein the articles are collected from the lower stacking plate into a position in which the articles are deposited on a surface; and
means for securing the guide bar selectively in a first angular position about the horizontal pivot axis in which the upper stacking plate is constrained to deposit columns of the covers forming the articles in a vertical orientation on the surface and columns of the cups forming the articles in a horizontal orientation on the surface.
More specifically, the articles ejected from the thermoforming machine are picked up by a lower stacking plate which has an upper stacking plate complementary thereto and raisable and lowerable in a displaceable pivot arm. The pivot arm is swingable in a slider provided with guide rollers which ride a lever-like guide bar itself adjustable between two positions or respective orientations with respect to a horizontal axis, in one position of which collected cups can be deposited in a horizontal position whereas in a second position of that bar, covers are deposited so that the stacks thereof are vertical.
The stacking apparatus of the invention can be retrofitted on existing thermoforming machines, preferably on thermoforming machines of the type described in German patent document 197 16 655 which provides an inclined thermoforming machine in which the ejected articles are picked up in an inclined orientation. The stacking apparatus can be used for collecting containers and cups in a universal manner from thermoforming machines for making such containers or cups.
With the system of the invention, depending upon the geometric configuration of the articles produced (containers or trays on the one hand or covers and shells on the other), the articles can be deposited in a horizontal orientation or a vertical orientation and the orientation on deposition can be matched to the requirements of further processing, e.g. the finishing program. The switchover can be effected by only a simple manual resetting of the position of the guide bar so that the latter is either in its upper or lower positions and can be arrested in either. The arresting element may be a detent or catch arrangement provided directly on the bar. When the stacking apparatus is used with a vertical thermoforming machine, the finished articles can be transported from the thermoforming machine in a foil grid and picked up by the stacking apparatus
During the operation of the pivot arm, the latter is constrained to swing either into a horizontal orientation or into a vertical orientation after the articles have been picked up from their inclined positions, to deposit respective collections of articles on the receiving plate in horizontal collections or stacks or vertical collections or stacks dep
Hüttig Jörg
Wolk Frank-Michael
Dubno Herbert
Fischetti Joseph A.
Gabler Maschinenbau GmbH
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