Conveyors: power-driven – Conveyor for changing attitude of item relative to conveyed... – By conveyor and means driven for turning successive conveyed...
Reexamination Certificate
1999-03-30
2001-04-10
Bidwell, James R. (Department: 3651)
Conveyors: power-driven
Conveyor for changing attitude of item relative to conveyed...
By conveyor and means driven for turning successive conveyed...
C198S401000
Reexamination Certificate
active
06213282
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method for positionally accurate feeding in sequence of sheet-like objects to a treatment process and aligning them, adjusting delivery and skew and relates to apparatus for the above-noted positionally accurate feeding of sheet-like objects to a treatment unit.
A method and an apparatus of the type mentioned above are known. To satisfactorily paint or print sheet-like objects, in particular sheet-metal plates, they must be fed to a treatment process, for example a painting or printing process, in a positionally accurate manner. It is known to mechanically align the sheet-metal plates using side markers, feed guide markers, plate stops, or the like. The sheet-metal plates, which are conveyed lying one behind the other, hit the feed guide markers or stops during the conveyance, to urge the sheet-metal plates into the desired or accurate position. A skewed position correction may develop. For example, the front edge of the sheet-metal plate may be aligned so that it is essentially at right angles to the conveying direction. Furthermore, the sheet-metal plate is aligned laterally, so that it can be fed to the treatment process in a central position. Finally, optimum longitudinal alignment of the sheet-metal plate with respect to the conveying path is required, in order for the plate to be fed to the treatment process or the treatment unit at the correct time.
Since the desire to save materials means that the sheet-metal plates become gradually thinner and because ever higher production rates are required, the known methods and apparatus may often cause damage to the edges of the plates, since the sheet-metal plates strike the stops or feed guide markers at a high velocity. This particularly damages sheet-metal plates of a small plate thickness.
SUMMARY OF THE INVENTION
Therefore, the object of the invention is to provide a method and an apparatus for positionally accurate feeding of sheet-like objects to a treatment process or a treatment unit, which achieve high production rates even for thin plates.
The object is achieved by the following method. The sheet-like objects are conveyed in succession in a lying position and are aligned during the conveyance, so that the objects are fed to a treatment process in a positionally accurate manner. The invention provides for rotational movement of the object to correct a skew position of the front edge of the object. For lateral alignment, a lateral movement of the object is carried out transversely, in particular at right angles, to the conveying direction. Longitudinal alignment of the object is achieved by accelerated or decelerated longitudinal movement in the conveying direction. If the position of an object is corrected, the object does not strike a stop, or the like. Instead, a drive force and/or a drive moment is applied to the sheet-like object, in particular a sheet-metal plate, which force/moment causes the applicable rotational movement, the lateral alignment, acceleration or deceleration of the object. This makes it possible to increase the production rate of the treatment process, i.e. to treat a higher number of objects per unit time. Furthermore, it also makes it possible to process particularly thin sheet-metal plates without damaging them.
In a preferred embodiment, the object undergoes preliminary alignment. This means that the object or the sheet-metal plates are roughly aligned before the accurate position for feeding the object to the treatment process is reached. The preliminary alignment may be provided particularly when the objects are supplied from a feeder, which is also known as a separating device, because the feeder supplies the objects in a relatively inaccurate position for conveyance to the treatment process. To enable the positionally accurate alignment of the sheet-metal plates to take place immediately before they are fed to the treatment process, there is provision particularly for the skew position correction, the lateral alignment and the longitudinal alignment to be carried out within a relatively narrow tolerance range, so that the objects do not have to cover unnecessarily long distances immediately before the treatment process. This permits the positionally accurate alignment to take place relatively quickly.
In a further development, when the object is transferred to the treatment process, its feed velocity is equal to or approximately equal to the velocity of an object in the treatment process. This produces particularly good treatment results in the subsequent printing or painting unit.
In preferred exemplary embodiment, the object is at least temporarily held fixed to its conveying support during the conveyance. This enables the object to rest on the conveying support. As an alternative, the object may be conveyed in a suspended manner and thus to be held on its large area top side. In particular, the object may be held in place by a magnetic and/or vacuum or suction effect.
In an exemplary embodiment, the rotational, lateral and/or longitudinal movements of the object take place simultaneously, or at least two of these movements take place simultaneously.
In a further preferred embodiment, the rotational, lateral and/or longitudinal movements take place in succession. There is provision in particular for at least the rotational movement, and then, if appropriate, the lateral and/or longitudinal movement, to take place.
A further development of the invention provides for the actual position of the object to be detected or determined in order to correct its skew position, and/or lateral position and/or longitudinal position.
A still further development of the invention holds the object in place by being sucked on by means of a vacuum or by a magnetic field during the first conveying path. In this case, a skew position of the object is detected in the area of the first conveying path. Afterward, rotational movement is performed for correcting the skew position. Then, the object is transferred to a second conveying path. At the same time, the vacuum or the magnetic field in the area of the first conveying path is gradually removed, while a vacuum or a magnetic field is built up in the area of the second conveying path in order to hold the object. After this, the lateral position and the longitudinal position of the object are determined. If a correction is required, the lateral movement and/or the longitudinal movement is/are carried out in the area of the second conveying path. Finally, the object is fed to the treatment process at a conveying velocity which corresponds to or is equal to the object velocity in the treatment process.
The invention also concerns apparatus for positionally accurate feeding of sheet-like objects to a treatment unit. In particular, sheet-metal plates are fed in a positionally accurate manner to a printing or painting unit of a sheet-metal coating machine, which forms the treatment unit. The objects to be fed are positioned in succession in a lying position. The objects are conveyed by a conveyor device. The objects are aligned during conveyance by an alignment apparatus. In order to correct a skew position of the front edge of an object, the conveyor apparatus is mounted to be rotatable about a shaft or it has two conveyor means which lie at a distance from one another and are able to adopt different conveying velocities. The different conveying velocities of the conveyor means allow the object to be rotated to corrects its skew position. For laterally aligning the object, the conveyor apparatus is displaceable transversely to the conveying direction. For longitudinal alignment of the object, the conveyor apparatus may be displaceable in the conveying direction. As an alternative, the conveyor means of the conveyor device may be capable of being accelerated and/or decelerated. Because the conveyor apparatus can be displaced and/or the conveying velocities of the conveyor means can be varied, for positionally accurate alignment of the object, this makes it possible to dispense with mechanical stops which may dam
Gericke Stephan
Mokler Bernhard
Vollmann Andreas
Bidwell James R.
LTG Holding GmbH
Ostrolenk Faber Gerb & Soffen, LLP
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