Patent Application
20100032882
This application claims the priority of the European Patent Application No.: 08162120.3, filed on Aug. 8, 2008, the subject matter of which is incorporated herein by reference.
The invention relates to an apparatus for separating and removing individual printed products from the underside of a stack of printed products and supplying these printed products to a processing section. The apparatus comprises a conveying rotor having least one separating element in the region of the circumference, provided with a pivoting suction mount that is arranged at a distance and parallel to the shaft of the conveying rotor and is embodied with a suction head, attached thereto, for partially lifting respectively one printed product from the stack and moving it to the circumferential region of the conveying rotor. The apparatus furthermore comprises an activation mechanism, designed to control the movement of the separating element for partially lifting a printed product off the stack end.
An apparatus of this type is disclosed in European patent application EP-A-1 197 449 (corresponding to U.S. Pat. No. 6,698,749, the disclosure of which is incorporated herein by reference in its entirety), wherein
To make possible a reliable withdrawal and separation of the printed products from the stack, the gripping surface of the suction head on the one hand must follow the aforementioned tilting curve and thus must follow a circular arc, an involute curve or a different curve. On the other hand, the suction surface should be kept tangential to the product to be tilted. If an angle error develops, there is a danger that the suction head loses contact with the printed product or that insufficient time is available to properly build up the holding vacuum, especially with more rigid printed products and at high processing speeds. The vacuum required for gripping a printed product can be generated only if the suction head or the suction mount has come to rest correctly against the sheet as a result of the pivoting movement. A proper separation of the printed products is not ensured if too little time is available for generating the holding vacuum. If the suction head is not guided correctly, lateral forces and moments will additionally be generated, which can cause the suction head to lose contact with the printed product. With a separating element as disclosed in the European patent application EP-A-1 197 449, the two above-stated requirements can be met only in part.
It is an object of the present invention to provide an apparatus of the aforementioned type, which avoids the mentioned disadvantages. The apparatus is thus intended to make possible a higher processing speed as well as a reliable withdrawal of even comparatively stiff printed products from a stack.
The above and other objects are achieved according to the invention wherein there is provided, in one embodiment, an apparatus for separating and removing a flexible flat object, such as a printed product, from an underside of a stack of flexible flat objects, and for supplying the objects to a processing section, comprising: a conveying rotor including a central axis, a shaft arranged concentrically with the central axis and at least one separating element located in a circumferential region of the conveying rotor to respectively lift at least partially one of the flexible flat objects from the stack and deposit the object in a region of the circumference of the conveying rotor, the separating element including: a suction mount pivotally arranged on the conveying rotor and positioned at a distance from and parallel to the shaft; a suction head attached to the suction mount to pivot with the suction head and to grip the flexible flat object with a suction force; an activation mechanism to control a pivoting movement of the suction mount when an object is partially lifted from an end of the stack; a joint coupled to the suction mount; and a control device connected to the joint to effect a further pivoting movement of the suction mount.
As a result of the joint and the control device, it is possible to control the path and the angle position of the at least one suction head so that the aforementioned angle error can for the most part be avoided. The joint permits a further, second degree of freedom for the movement of the at least one suction head. With the additional degree of freedom resulting from the joint and the control device, it is possible to correct the pivoting movement of the separating element. Interfering influences such as shearing forces, pulling forces, or tilting moments of the at least one suction head on the gripped printed product can thus be avoided. The individual printed products can thus be picked up faster and more securely. More time is furthermore available during the specified cycle to generate the holding vacuum.
According to one embodiment of the invention, the joint is arranged on the suction mount, which permits a particularly easy but nevertheless reliable movement of the at least one suction head with the aid of the control device. The suction mount can furthermore include one or several suction heads. Several suction heads can be moved simultaneously by pivoting the suction mount around the joint. This movement is superimposed on the movement of the separating element around a shaft for the separating element. The suction mount and the suction head thus carry out a pivoting movement, which can be understood to be a corrective movement.
According to a different embodiment of the invention, the shafts for the activation mechanism and the suction mount extend parallel to each other, which permits a particularly simple and secure control of the aforementioned movements.
Yet another embodiment of the invention provides that the suction mount is positioned via a lever gear on the activation mechanism, thereby also permitting a particularly easy control of the suction mount. Respectively two levers are connected by the joint, wherein one lever is connected to the shaft of the activation mechanism and the other lever is connected to the suction mount and wherein the joint advantageously is a pivoting joint. The joint may comprise two joints, at a distance to each other. A joint of this type can be realized particularly easily, securely and cost-effectively.
According to a another embodiment of the invention, the at least one suction head extends essentially at a right angle to the longitudinal extension of the suction mount. The production of the suction mount is thus simple and, in particular, it is comparatively easy to produce the through openings for connecting the at least one suction head to a vacuum source. A further embodiment of the invention provides that the control device comprise a cam curve. Yet another embodiment provides that the control device has at least one cam roller which operates jointly with the aforementioned cam curve. This cam curve may be arranged on a cam disc that rotates along, wherein other control devices are conceivable as well. For example, the suction mount could be pivoted with a separate drive such as a motor. The aforementioned cam roller for another embodiment of the invention is arranged on the suction mount. However, it is advantageous to have two cam rollers arranged on the suction mount, thus making possible an especially easy and secure movement of the suction mount and the at least one suction head.
According to yet another embodiment of the invention, the movement of the at least one suction head around the joint is coordinated with the movement controlled by the activation mechanism. In particular, the further pivoting movement of the at least one suction head is coordinated with a pivoting movement caused by the shaft of the activation mechanism. The movement of the at least one suction head may be controlled or coordinated so that the suction head only carries out the necessary corrections, which makes possible a precise orientation of the suction surface toward the printed product to be separated.
The movement of the at least one suction head may be coordinated with the movement of the activation mechanism so that during one cycle interval, a suction surface of the at least one suction head is oriented toward the printed product to be tilted and separated. A particular advantage is that the contact between the suction head and the printed product is not lost when comparatively rigid printed products are separated.
The apparatus according to the invention may, in particular, be a feeder, for example a gathering chain, a gathering channel or an inserting machine, for supplying a transport section or a processing station.
These and other features and advantages of the invention will be further understood from the following detailed description of embodiments of the invention with reference to the accompanying drawing.
a is schematic that shows the individual phases of the separating element movement during the separating of a printed product from a stack according to the prior art.
b is a schematic similar to
Referring to
At least one separating element T is positioned on the conveying rotor 2 and is provided for separating and withdrawing the printed products 25. With the embodiment shown herein, two diagonally opposite-arranged separating elements T are provided, but only one of the two separating elements T is shown herein for ease of illustration. The separating element T comprises a control shaft 16, which is positioned pivoting with the aid of respectively one rotating bearing 19 on two opposite-arranged cam discs 6. The two cam discs 6 are connected to the rotor shaft 3, such that they rotate along. At least one end of the control shaft 16 is provided with a pinion 18 that is intended for pivoting the control shaft 16 and thus also the separating element T during a rotating movement of the conveying rotor 2. The control shaft 16 and the pinion 18 thus function as an activation mechanism for the separating element T. For this, the pinion 18 can engage in another control not shown herein, such as a toothed gearing, wherein suitable control apparatus is known per se to one skilled in the art. In principle, the control shaft 16 could also be pivoted directly with a motor that is not shown herein. The separating element T is furthermore provided with a suction mount 9 that is connected pivoting via a lever gear to the separating element T. Two joints 21, arranged at a distance to each other, respectively connect a lever arm 14 to a lever arm 22 of the lever gear. As can be seen, the lever arm 14 has an angled design. The lever arm 22 is fixedly connected to the suction mount 9, which extends parallel to the control shaft 16 and also parallel to the rotor shaft 3, as shown with the dash-dot line 32 (
The lever arm 22 is comparatively short and, in particular, is shorter than the arm 14, as shown in
Attached to the suction mount 9 are spaced apart suction heads 11, which are provided according to
During the rotation of the conveying rotor 2, the suction heads 11 are moved so that they respectively approach the bottom printed product 25 from below with the suction surface 12, as shown in
When lifting a printed product 25 from the stack end and transferring it to the conveying rotor 2, the separating element T basically executes a pivoting movement around the control shaft 16, as indicated in
a and 5b illustrate a comparison between the movement of the separating element according to the prior art and the movement of an apparatus 1 according to the present invention. Four different phases of these movements are shown by the lines A, respectively A′. According to the prior art shown in
The invention has been described in detail with respect to various embodiments, and it will now be apparent from the foregoing to those skilled in the art, that changes and modifications may be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the appended claims, is intended to cover all such changes and modifications that fall within the true spirit of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 08162120.3 | Aug 2008 | EP | regional |
