Destacker for small flat packages such as audio/video cassettes and the like

Abstract: A destacker (1) for small flat packages (P) such as audio or video cassettes (P) includes a gripper (20) for gripping a vertically oriented package (P) of a horizontal stack of such packages, and transferring the package (P) to a releasing location (C) while simultaneously repositioning the package (P) into a horizontal orientation. The gripper (20) is mounted to a pair of pivoted links (5,9). An actuator (8) causes the links (5,9) to rotate such that the gripper (20) is transferred while being initially rotated in a first direction (D3) and finally being rotated in an opposite direction.

Description: The present invention relates to the handling of packaged articles that are to be handled with care, and especially the destacking of packages wherein a package of a stack of the packages is to be removed from the stack and transferred to another location. Systems are known which convey a horizontal stack of packages, such as compact disks and audio cassettes, along a substantially horizontal support and lay them, for example, onto a conveyor belt. It is known that packages of products like compact disks and audio cassettes are covered with a material that is readily subject to scratching. Even though scratches on the cover do not jeopardize the package or the product, they are nonetheless felt to be a defect, and the utmost care is consequently applied to avoid them. For example, in the packaging plants such scratches can result from a rubbing together of adjacent packages that causes abrasion of the packages. In that regard, the CDs, after being packaged, are usually introduced, in a vertical (upright) orientation onto an essentially horizontal guide to form a horizontal stack of packages which is advanced, until the packages fall, or are laid, onto a conveyor belt and transferred to a station at which they are packed for shipment. During such a handling, the rubbing of the packages against one another, or against a surface, can occur thereby causing scratches. US-A-4,042,126 discloses a destacking apparatus for removing packages from a horizontal stack of the packages that are resting on an upwardly facing support surface. The apparatus includes a support mounted to a frame by a linkage. The support includes a rod, and a bracket projecting at an angle from the rod. The bracket includes suction devices for releasably mounting the package to the support. The linkage displaces the support from a package-receiving location at the stack, to a package-releasing location. The linkage comprises first and second links each having one end pivotably connected to the frame and another end pivotably connected to the support. The stack of packages is arranged on the supporting surface such that the front surface of the leading package rests against upper and lower stationary retaining rods. Thus, before the leading package can be moved in a direction away from a plane of the front surface of the following package, it is first necessary to reposition the leading package so that it can be moved past the retaining rods. Such re-positioning involves sliding the leading package along the front surface of the following package, which can lead to a scratching of the packages as described earlier. The present invention proposes a destacking apparatus for individually taking a package that is arranged in an upright position, while avoiding any impact or friction against an adjacent package, and laying it onto a conveyor belt such that it lies on its larger surface. The apparatus should operate reliably and be capable of being made in a simple, cost effective way. The invention relates to a destacking apparatus having the feature as defined in claim 1. Brief Description of the Drawing The objects and advantages of the invention will become apparent from the following detailed description of preferred embodiments thereof in connection with the accompanying drawing in which like numerals designate like elements, and in which: Fig. 1 illustrates a destacker according to the invention during a step in which a package is received; Fig. 2 illustrates the destacker of Fig. 1 during a package releasing step; and Fig. 3 illustrates the destacker immediately following the initiation of the package-receiving step. Detailed Description of a Preferred Embodiment of the Invention Referring to the figures, a destacker 1 comprises a gripper or support for gripping packages P such as CDs, the gripper preferably including suction cups 2 movable between a removing position (Fig. 1) and a releasing position (Fig. 2) by means of a kinematic mechanism 3. In particular, the suction cups 2 are fixed to a bracket 20, the bracket being fixed to an end of a rod 4 that reciprocally moves, with a rototranslation motion, between a first essentially horizontal position, which is shown in Fig. 1, and a second essentially vertical position, shown in Fig. 2, for taking a vertically oriented package P from the front position of a stack S of the packages that is advanced along a guide 6, and laying the package onto a conveyor belt C in an essentially horizontal orientation. Rod 4 is displaced by the mechanism 3 which includes a pair of connecting links 5 and 9. A first end of the rod 4, i.e., an end to which the bracket 20 is fastened is hinged by a horizontal pin 4A to the connecting link 5 which, in turn, is hinged by a horizontal pin 5A to a fixed machine frame 7. A second end of rod 4 is hinged by a horizontal pin 12 to the connecting link 9 which is shorter than the connecting link 5. The link 9 is also hinged to frame 7 by a horizontal pin 9A. A piston 8 includes a rod 8A which is hinged intermediate its ends by a horizontal pin 8B to frame 7, and a cylinder 8C which is hinged by a horizontal pin 8D to the connecting link 5. The piston 8 controls the rotation of connecting link 5 around the pin 5A. Upon actuation of the piston actuator 8 whereby the actuator is extended, the connecting rod 5 is rotated about the pin 5A, causing the rod 4 to rotate about pins 4A and 12. Pins 12 and 4A themselves are constrained to move along first and second circular paths A1 and A2, respectively, which circular paths have pins 5A and 9A as their respective centers of rotation. It will be appreciated that the first path A1 has a shorter radius of curvature then the second path A2, and the center of curvature 9A of the second path A2 lies inside of a circle defined by the second path A2. The operation is as follows: --- When piston 8 is caused to retract, the support 20 assumes a vertical position in parallel with the surface of the CDs that are advanced along the guide 6, while the suction cups 2 are brought into contact with the first package to be taken. --- The suction cups are then energized in a known manner, for example by sucking air from the inside part thereof, in order to cause them to adhere to the first package P, whereafter the piston 8 is extended to rotate the links 5 and 9 counterclockwise in directions D1, D2 (see Fig. 3). During the initial rotation of links 5 and 9, the pins 4A and 12 travel downwardly along the paths A2, A1, respectively. Since the radius of curvature of path A1 is greater than that of path A2, the pin 12 travels downwardly at a faster speed than the pin 4A, causing the rod 4 to pivot clockwise in the direction indicated by arrows D3 as shown in Fig. 3. Therefore, even though both ends of the rod 4 are moving downwardly, the suction cups 2 are swinging upwardly relative to the pin 4A, since the support 20 is pivoting clockwise about that pin 4A. As a result, the package P tends to rotate clockwise about an axis located in the region of its lower front edge 24, causing it to be separated from the next package in the stack. Due to the relatively short distance between the pins 4A and 12, the angular speed, i.e., the speed of rotation of the support 20, is appreciably greater than that of the connecting link 5, so the separation occurs relatively quickly. During continued rotation of the links 5 and 9, and before the links 5 and 9 reach a vertical orientation, the support 20 is displaced up and away from the guide 6 while being rotated clockwise. When the links 5, 9 pass their vertical dead center orientations, the pins 12, 4A begin to move upwardly. Again, due to the shorter length of link 9 relative to link 5, the pin 12 will ascend more rapidly than the pin 4A, causing the support 20 to reverse its rotation, i.e., to rotate counterclockwise. That occurs until the links reach the release position of Fig. 2, whereupon the package P has assumed a horizontal orientation and can be placed onto the conveyor C to which it is now oriented parallel. The suction cups are then deenergized to allow the package P to fall onto the conveyor. The stack of packages P is advanced to position the next package in place to be gripped by the suction cups. It will be appreciated that the piston 8 could be connected to the link 9 rather than to the link 5. Also, the rod 4, and the links 5 and 9 could be provided in the form of parallel, spaced apart pairs, i.e., two rods 4, two links 9, and two links 5. Also, an actuator other than a linear actuator 8 could be used, such as a rotary actuator. Moreover, the apparatus could be operated in reverse to transfer a package from a horizontal orientation to a vertical orientation. The present invention enables packages such as CDs, audio cassettes and the like to be transferred from one place to another without causing the packages to be scraped, and thereby avoiding the application of scratches as to the package. Although the present invention has been described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims: A destacking apparatus for sequentially moving packages (P) from a horizontal stack of the packages, wherein lower edges of the packages rest on an upwardly facing support surface, and wherein a leading package in the stack includes a rear surface engaging a front surface of a following package located adjacent to the leading package; the destacking apparatus comprising a frame (7) a support (4, 20, 2) including a rod (4), a bracket (20) rigidly connected to and projecting at an angle from the rod (4), and a gripping device (2) disposed on the bracket and releasably mounted to the leading package of the stack; a linkage (5, 9) for displacing the support from a package-receiving location to a package-releasing location; the linkage comprising a first connecting link (5) having one end hinged to the frame by a first pin (5A) and a second end hinged to the support by a second pin (4A), and a second connecting link (9) having one end hinged to the frame by a third pin (9A) extending parallel to the first pin, and a second end hinged to the support by a fourth pin (12) extending parallel to the second pin (4A); the first (5) and second (9) links being oriented relative to one another to cause the second and fourth pins (4A, 12) to move along different respective paths of travel (A1, A2) during rotation of the links relative to the frame; and an actuator (8) for producing rotation of the first and second links relative to the frame; characterized in that the upper portion of the leading package is movable unobstructedly in a direction away from a plane of the front surface of the following package; and the respective paths of travel of the second (9) and fourth pin (12) being circumferences (A2, A1) of different radii having centers located in the first pin (5A) and third pin (9A) respectively so to cause the gripping device (2) to move in a way that the upper portion of the leading package (P) initially move away from the plane of the front surface of the following package more quickly than the lower portion of the leading package, whereby the leading package is initially swung away from the plane of the front surface of the trailing package to prevent the rear surface of the leading package from scraping against the front surface of the following package. The destacking apparatus as claimed in claim 1 wherein the gripping device (2) comprises a plurality of vertically spaced suction cups. The destacking apparatus as claimed in claim 1 wherein the first (5) and second (9) links project downwardly from the frame. The destacking apparatus as claimed in claim 3 wherein the first and second links converge toward one another in the downward direction, whereby a distance between the second and fourth pins (4A, 12) is shorter than a spacing between the first and third pins (5A, 9A). The destacking apparatus as claimed in claim 4 wherein the second link (9) is shorter than the first (5) link, and the third pin (9A) lies inside of a curve formed by the path of travel (A2) the second pin (4A).

Inventors: CANZIANI FRANCESCO, TACCHI RENATO, CANZIANI, FRANCESCO, TACCHI, RENATO
Applicants: CML HANDLING TECHNOLOGY S P A, CML HANDLING TECHNOLOGY S.P.A.
Application year: 1996
Main classification: B65G47
IPC codes: B65G47, B65G59