Method and Apparatus for Braking and Delivering Printed Sheets or Sheet Packages

Reference to related publication documents:

British Pat. No. 747,444,

German Pat. No. 27 50 792.

The present invention relates to handling of printed sheets or sheet packages, hereinafter referred to, collectively, as "copy elements", and more particularly to a method and apparatus for braking of copy elements received at the high rate of speed from a printing machine and which are to be delivered to a delivery apparatus, such as a belt.

Copy elements received from a folding former or other folding apparatus are furnished at high speed; it is known to receive these copy elements with a rotating gripper cylinder and to deliver the copy elements in imbricated or shingled form on a delivery mechanism, for example a delivery conveyor belt--see for example the referenced British Pat. No. 747,444. It is also known to use rotating paddle wheels or the like in which the copy elements are received. The paddle wheels have paddles or vanes which receive the furnished copy elements for further handling and delivery. These copy elements, also arriving at high speed, are braked and then placed in imbricated, shingled or overlapping position on delivery belts. These known devices all have the disadvantage that, as the copy elements engage in the respective pockets of the paddle wheels, grippers, or other engagements strips of the rotating cylinders--which, necessarily, must operate at the circumferential speed less than the arrival speed of the copy elements--cause the leading edges of the copy elements to be deformed by compression thereof. Further, it occurs from time to time that the copy elements ricochet at the engagement or abutment elements, grippers or paddle wheels, causing at least partial misfeeds. This disadvantage occurs in rotating elements as well as in arrangements in which belts and the like operating at differential speed and using alignment and braking strips, in accordance with German Pat. No. 27 50 792, are employed.

It is an object to provide a method which, preferably, utilizes available well known structures which have only been slightly modified, in which copy elements can be braked after having been supplied at high speed. Additionally, the method and apparatus should be capable of carrying out its function while using only minimum space, and effectively avoiding danger of deformation of the leading edges of the copy elements or bounce-back thereof.

Briefly, the arriving copy elements, which also be referred to as copy substrates, are deflected from their path of arrival in a circular path, by engaging the leading edge of the respective copy element with engagement flaps on a gripper cylinder. These engagement flaps may, merely, be extensions of the grippers of the gripper cylinder. The leading edges of the copy elements, thus, are caught between the gripper cylinder and the engagement flaps without, however, initially engaging the leading edge against the and, or back portions or abutment portions of the gripper elements. The leading edges of the copy elements are thus directed away from their prior path, so that the leading edges are guided about the circumference of the gripper cylinder. The copy elements have a forward momentum which, eventually, will cause the leading edges to abut against the grippers, at which point the grippers will close. Yet, the gripper cylinder, which operates at the slower circumferential speed than the arrival speed of the copy elements, has already rotated over a portion of a revolution, which caused flexing of the copy elements to thereby convert some of the energy which otherwise would be expended on impinging against the grippers into bending of the copy elements. As the gripper cylinder continues to rotate, the copy elements are flipped over due to centrifugal force acting on non-gripped or free portions of the copy elements. This permits the trailing edge of the subtrate of the copy element to overrun the leading edge of the substrate gripped by the grippers of the cylinder due to the kinetic energy still residing in the copy elements. When the gripper cylinder has rotated so that the grippers are adjacent a delivery transport mechanism, typically a delivery belt, the grippers release the now turned-over elements for further distribution. The delivery transport belt, as well as the gripper cylinder, run at a slower speed than the supply speed; the method permits conversion of kinetic energy into bending stresses in the copy elements and prevention of engagement or impinging shock of the leading edge against a gripper abutment which operates at a lower speed.

The basic structure to carry out the method can be conventional, except that the direction of operation of the delivery transport mechanism is reversed with respect to prior art structures, namely counter the direction of rotation of the gripper cylinder; additionally, the grippers are so constructed that they have extending portions which, when open, form deflection elements which guide the incoming leading portion of the copy elements into and toward the grippers without, however, presenting an abutment surface therefor. Additionally, deflection shields or sheets should be provided, for example in the form of sheet-metal deflectors, to guide the incoming copy elements and the trailing portions of the copy elements as they are being flipped over by the gripper cylinder.

In accordance with a feature of the invention, the grippers on the gripper cylinder bend the copy elements before braking the copy elements, that is, before the copy elements impinge with their leading edge against the gripper abutment surfaces themselves. The grippers can be readily controlled to open and close in cadence with rotation of the gripper cylinder, and bending the incoming copy elements by engagement with the open-end portions of the grippers utilizes centrifugal forces being exerted on the copy elements to effectively brake the copy elements while turning them over. The system also permits maintenance of the direction of movement of the copy elements as received and as delivered, although they are delivered, turned over. Selectively, the copy elements may additionally be bent by stationary auxiliary structures, such as deflection shrouds or the like. The leading edges of the copy elements engage the gripper extensions on the gripper cylinders and are deflected downwardly out of their prior supply plane.

The method and apparatus has the advantage with respect to all known braking and aligning and delivery systems that the kinetic energy in the copy elements, as they are being delivered at high speed, is not absorbed by impact engagement resulting in deformation, at the gripper surfaces of the necessarily slower running gripper cylinder; rather, the kinetic energy is converted into bending work and, finally, changes the orientation of the copy element, by turning it over. The arrangement has the additional advantage that, as the copy elements are slowly fitted into the grippers, an air cushion will occur which also will occur behind the copy elements as they are being flipped over, which air cushion or air pillow will also assist in braking and, by compression of the air, absorption of energy, so that the copy elements can be delivered at a speed which is slower than the arrival speed.

FIG. 1 is a general side view of a braking apparatus carrying out the process in accordance with the invention;

FIG. 2 is a sectional view along the broken section line I-II of FIG. 1;

FIG. 3 is a section through the gripper cylinder along the line III--III of FIG. 2;

FIG. 4 is an enlarged fragmentary view to illustrate the sequence of acceptance of a copy element by the grippers of a gripper cylinder; and

FIG. 5 is an enlarged fragmentary view of the gripper cylinder to illustrate the force relationships arising at the instant of braking of the copy element.

A single sheet or package of sheets, collectively referred to as "copy element" 1, is illustrated in the respective FIGS. 1, 4, 5 in various positions. The various positions of the copy element 1 are illustrated in these respective drawings by the reference numerals 1a-1i. Referring now to FIGS. 1 and 4: A sheet 1a is being supplied to the braking apparatus by a belt transport apparatus, in accordance with well known construction. A supply guide sheet 3a guides the copy element 1a in an essentially horizontal plane to a rotating gripper cylinder 4. The gripper cylinder 4 has at least one gripper system 5 which extends axially across the gripper cylinder 4 in accordance with well known construction. The gripper system 5--see also FIG. 3--is slightly modified, however, in that the grippers themselves are formed with extension portions 5'. Usually, more than one gripper may be located on the gripper cylinder, and FIG. 3 illustrates, for example, two such gripper systems 5, the lower one in FIG. 3 not being further described since it can be identical to the upper one. Preferably, grippers are formed with relatively long extension or tongs 5' which are used to bend the leading edge of an arriving copy element 1--see FIG. 4, at 1c. The gripper positions associated with the respective copy element positions 1a-1i are identified at 5a-5i. Of course, the gripper cylinder 4 operates at a lower circumferential linear speed than the arrival speed of the copy elements supplied by the incoming belt system 2.

The position of the leading edge of the copy element is shown and identified by the reference numerals 1b-1f. In these positions, the leading edge of the copy element gradually approaches the gripper which, further, forms an abutment surface, which can best be seen in FIG. 4 when considering the associated gripper positions 5b-5f. In accordance with a feature of the invention, the leading edge of the copy element is deflected, in the embodiment shown, deflected downwardly or, in other words, the leading edge is bent or bowed with respect to the remainder of the copy element and, further, bent directly, starting with the position 1c. At the position 1f, the gripper, at the associated gripper position 5f, will actually grip the copy element. The kinetic energy inherent in the copy element, due to its high delivery speed, at first results in an approximately straight-forward directed force which, as seen at 1g, further bends the copy element. The force center or force effective point is shown at 16 in FIG. 4. The sheet 1f, gripped at the gripper position 5f, is guided by the deflection sheets 3b, 3c and, upon continued transport in the direction of the arrow 11 of the copy element, and while being held with the leading edge in the gripper cylinder 4, the copy element is flipped over or turned by 180.degree.. Thus, the previously trailing end of the copy element becomes the leading end thereof; the original leading end becomes the trailing end, as soon as the copy element is deposited on the delivery belt system 6 at which time the gripper cylinder 4 controls the respective gripper to release the copy element. Since the copy elements arrive at a faster speed, sequentially, and are delivered at a slower speed, the copy elements must overlap, that is, they will be furnished in imbricated or shingled condition. This braking and turning process is particularly advantageous due to the resulting air resistance. As can be seen in FIG. 1, the copy is released, so that it can align itself on stationary engagement tongs or stops 20. Arrow 19, engaged at the center of gravity or center of force engagement, illustrates the direction in which the copy element 1i will flip or turn. As schematically indicated by the arrow 19, the resulting kinetic energy will cause the copy element to stretch out, engaging the leading end against the delivery belt 6. Delivery belt 6 operates in the direction of the arrow 7 which is counter the direction of movement of the surface of gripper cylinder 4, i.e., adjacent a delivery position.

The gripper cylinder 4 is retained between side walls 9, 10--see FIG. 2. The gripper cylinder 4 is driven in the direction of the arrow 11 (FIG. 1) and, in turn, is coupled over gear belts 12 to a belt roller 8 which controls and causes movement of the delivery belt 6 in the direction of the arrow 7 (FIG. 1). Considering FIGS. 2 and 3 together: Grippers 5 are positioned on gripper spindle 13 which, in turn, are coupled via a cam follower 14 with a cam track 15 to cause, respectively, rotation and opening and closing movement of the grippers 5.

The copy element 1a, supplied by the supply belt 2, is braked by the gripper cylinder 4, operating at a slower linear speed; the copy element, additionally, is turned over, and then supplied to the delivery belt 6 which, likewise, operates at slower speed. The delivery is preferably in imbricated or shingled form when the sheets 1 are supplied to the gripper cylinder closely spaced from each other.

As best seen in FIG. 5, engagement of the leading edge of the already bent and deflected copy element 1f causes the center of gravity or center of force application 16 to first move in approximately unchanged speed in the direction of the arrow 17. The major portion of the mass of the copy element 1f thus does not participate in the impingement force of the leading edge against the gripper 5 when its leading edge engages the gripper--see the sheet 1f, FIG. 5. This substantially reduces the danger of damage at the leading edge of the copy element and effectively avoids danger of bounce-back or ricochet of the copy element. Further, the copy element is additionally braked by the air cushion or air pillow, in the direction of its weight, so that its kinetic energy, by compression of the resulting air pillow and the resulting deformation of the copy element itself, will be reduced. As best seen in FIGS. 1 and 4, the copy element is guided by the deflection and guide sheets 3b, 3c. These guide sheets are, preferably, adjustable in height and deflection angle to match the shape of the bending or bowing copy element to its characteristic--that is, whether the copy element is a single sheet, a plurality of packages of sheets, and the respective strength and bending characteristics of the material of which the sheet or sheets are made. Preferably, at least the level of position of the deflection sheets 3b, 3c should be adjustable, and the inclination of the sheet 3c should be additionally adjustable.

The grippers 5 may begin the opening movement already in advance of the position 5h, so that before they reach the position 5i in alignment with the abutment elements 20, the copy elements will be released from the grippers. The forces of the copy elements tend to move the copy elements in the direction of the arrow 19 (FIG. 1), which decreases the impact of the copy elements 1i on the abutment stops 20. These abutment stops 20 are stationary. Simultaneously, the movement of the sheets, in direction of the arrow 7 of delivery belt 6, is assisted by the force represented by the arrow 19. In some instances, it can be desirable to be able to shift the gripper cylinder forwardly and backwardly to match the transfer steps of the copy elements from the gripper cylinder, such shifting being carried out during rotation of the gripper cylinder, as well known, and not further described herein, since it does not form part of the present invention.

To insure transport of the respective copy elements 1 to the position 1f, the roller 18 of the supply belt system 2 is, preferably, shifted forwardly to the position shown in chain-dotted line at 18a, that is, if desired in advance of the customary position shown in full line at 18.

Various changes and modifications may be made within the scope of the inventive concept.