Patent Grant
8690149
This claims the benefit of German Patent Applications DE 10 2011 008 848.2, filed Jan. 18, 2011 and DE 10 2011 084 830.4, filed Oct. 19, 2011, both of which are hereby incorporated by reference herein.
The present invention relates to a receiving, holding and/or handling device for two-dimensional objects with at least two controllable suction grippers. A method for receiving, holding and/or handling two-dimensional objects with at least two controllable suction grippers.
During the processing of products and general cargo, especially during packaging, the products or cargo are often stacked in several layers one above the other. Intermediate layers are often inserted between the several layers of products or cargo. These intermediate layers are usually two-dimensional objects. The term two-dimensional object refers to layers of material, whereby the thickness of the material is negligible in comparison to the length and width of the material. The term two-dimensional object especially refers to intermediate layers made from film, paper or any other material with similar properties, especially to any flexible material with a negligible thickness. Such two-dimensional objects or plates may for example be formed by cardboard intermediate layers, plastic intermediate layers, twin wall sheets, sheets of corrugated cardboard, etc., either made from cardboard or plastic material. It is often problematic to raise such two-dimensional objects or stacked plates individually, because the objects or plates tend to stick to each other. The unwanted sticking effects are especially due to adhesion forces or mechanical fiber entanglement or low pressure attachment. These attachment forces have to be reduced or rendered ineffective during the lifting of the individual sheets or plates from a stack. Faster cycle times of gripping and lifting devices lead to more pronounced effects of these unwanted adhesion phenomena. To avoid or at least reduce the sticking of the plates, suitable brush elements can be used. When the uppermost plate is lifted, the plate under is retained by these brush elements. In practice it has been found that lifting and bending the lateral areas of the uppermost plate can be used as an effective measure to prevent the unwanted effect that the plate below is also dragged along. Another measure to avoid the problems mentioned above may be the use of frame magazines with a pre-separation of the plates.
EP 0 639 519 A1 shows a separation device for sheet or plate material with a plurality of vertically-oriented vacuum grippers. The vacuum grippers contact the uppermost plate for lifting. A peripherally arranged vacuum gripper is swivel-mounted and/or the support of the peripherally arranged vacuum gripper is displaceable in a horizontal direction. The peripherally arranged vacuum gripper can bend the peripheral area of the plate before the whole device is lifted.
A device for separating flexible plate-like objects such as metal plates by means of suction carriers, which are also called suction grippers, is also known from EP 1 215 148 A1. The majority of vacuum grippers are associated with peripherally located so-called separation suckers. The separation suckers are pivotable about an articulated joint by a small amount compared to the suction carriers working in a vertical orientation. The separation suckers can lift the peripheral areas of the uppermost plate from the underlying plate and can bend this peripheral area upwards.
EP 1864922 B1 discloses an apparatus and method for lifting an uppermost plastic plate or sheet from a stack of plates by means of suction grippers. The suction grippers are put onto the uppermost plastic plate. Then vacuum is applied and the uppermost plate is lifted from the stack. To prevent a sticking of the uppermost plate to the plate below, the lifted plastic plate is initially lifted parallel to the stack and then subjected to a two-way bending. The disclosed device for lifting the uppermost plastic plate from the plate stack includes a vertically movable carrier with suction grippers mounted thereon. The suction grippers can be connected to a vacuum source. On the carrier the suction grippers are arranged in pairs of external and internal suction grippers. The inner suction grippers can be temporarily connected to a vacuum source. The outer suction grippers can be temporarily and alternately connected to a vacuum source and a compressed air supply via a switching valve.
It is an object of the present invention to provide a reliable working device and a corresponding method for receiving, holding and/or handling two-dimensional objects by controllable suction grippers. The suction grippers should allow the lifting of individual two-dimensional objects like plates or something similar from stacks without requiring any additional helping means. Helpings means are for example magazines for the intermediate layers comprising brush elements and/or a pre-separation system or comprising other retaining systems for the underlying two-dimensional objects. The device should lift the uppermost plate without the underlying object or sheet being pulled along and/or without shifting the underlying object. For industrial applications it is of particular interest that high cycle times can be realized without any implication on the precision of the handling. Additionally, the device and the appropriate method should be economically feasible.
The present invention provides a receiving, holding and/or handling device for two-dimensional, sheet-like objects with at least two controllable suction grippers. The two or more suction grippers are each mounted to free ends of cantilever arms. The cantilever arms are movable and elastic at least in some sections or the cantilever arms are movable by articulated movements. The cantilever arms are mounted on a bridge and/or supported on a bridge. The suction grippers are preferably connected to the cantilever arms in a way that they cannot swivel in any arbitrary direction. Instead the suspension grippers have to perform their linear and pivoting movements in conjunction with the elastic and/or articulated movable cantilever arms. The cantilever arms are typically arranged symmetrically and wing-like. They each comprise at least one lower pull and one upper pull that meet at the free end of the cantilever arm. At the meeting point the upper and the lower pull are either connected in a substantially rigid connection, which is not movable in an articulated movement. For instance the upper and the lower pull are just supported at the meeting point in a so called flying mount. Additionally the respective suction gripper is connected to the cantilever arm at this meeting point. Alternatively this anchorage can also be rigid and not articulated. The anchorage of the suction grippers can also show some slightly elastic properties depending on the elastic properties of the upper pull and the lower pull.
An alternative embodiment may provide that the connection between the upper pull and the lower pull at the free end of the cantilever arm is formed bendable or articulated. In this embodiment, however, it is necessary that the suction gripper is either fixed to the upper pull or to the lower pull in such a way that the suction gripper is not articulately mounted at this point but at best only marginally elastically movable. Otherwise the precise control of the orientation of the suction grippers would be significantly impaired due to kinematic indeterminacy. Thus, the suction gripper is largely fixed rigidly to the lower pull. Typically the suction gripper is fixed to the lower pull in a rectangular orientation. Meanwhile the connection between the upper pull and the lower pull and/or between the upper pull and the encasing of the suction gripper can be constructed articulated or bendable.
In the area of the bridge the upper pull and the lower pull may optionally be mounted at a distance from each other. The lower pull is usually connected to the bridge at a defined position. A suitable actor, especially a tensioning means or pulling means, is associated with the upper pull. The actuator generates a variably controllable traction force or pulling force with at least one horizontal direction component, which is approximately parallel to the longitudinal direction of extension of the respective cantilever arm. Especially this actuator can be formed by a suitable pulling device such as a linear drive or the like. However, other fundamentally different operating principles can also be used, such as rotary drives. Rotary drives have pulling means that generate a pulling force in the desired direction. Pneumatic or hydraulic servo drives or adjustment cylinders are especially suitable linear drives. The pneumatic or hydraulic servo drives or adjustment cylinders can be designed as single acting or double acting. The required pulling force for the deformation of the cantilever arms, which elastically press back into their initial position, can optionally be applied by means of a suitable mechanical mechanism using a pressure cylinder.
Besides the aforementioned connection of separate lower pulls of two symmetrically arranged cantilever arms to the centrally located bridge other variations are possible. One of the other embodiments is provided with a single continuous lower pull extending along the two symmetrically arranged cantilever arms. The single continuous lower pull is either connected to the bridge or is supported on the bridge in a so called flying mount. In a flying mount the upper pull is just supported on the bridge during the upward movement of the suction grippers, whereby a convex curvature of the lower pull is performed. In the embodiment with the so called flying mount it may be sensible to ensure an exactly synchronous deflection of the actuators, servo cylinder etc. which are responsible for the deflection movements of the cantilever arms. This ensures that the pair of cantilever arms is not asymmetrically deformed or makes an evasive maneuver in one of the two longitudinal directions of the cantilever arms. An exact positioning of the suction gripper would thus be difficult. These problems do not occur when the lower pulls or the single continuous lower pull are connected by a central anchorage. The two cantilever arms are basically independently controllable and deformable without any negative impact on the positioning control of the suction grippers.
The device according to the invention allows a motion control of two or more suction grippers. This motion control is also known as “Fin-Ray”-principle. The trajectories of the suction grippers allow the lifting of plates, sheets or other two-dimensional objects from stacks. The objects are initially lifted peripherally, whereby the center area of the two-dimensional object is not yet removed from the underlying surface. However, the removal of the peripheral areas prevents the undesirable sticking-effects. The two-dimensional object can subsequently be lifted completely, without the danger that the underlying object is pulled along, moved sideways or influenced in any other undesirable way. Optionally the suction gripper simultaneously swings back into its original vertical position while the two-dimensional object is lifted. Likewise, it is also possible; to lift the two-dimensional object from the stack immediately after the suction gripper has been lifted, without the suction grippers first swinging back into their original vertical position.
According to a first embodiment of the invention the relatively rigid connection between upper pull, lower pull and suction gripper allows a desired and preferred trajectory of the suction gripper. When seen in a side view the trajectory of the suction grippers resembles a dynamic upward and downward movement of wings. To achieve these trajectories, whereby the cantilever arms are deformed over their entire length, it might be necessary that the connective joints between upper pull and lower pull as well as the connective joints between cantilever arm and suction gripper are not constructed articulated or bendable. Instead it can be useful to use rigid connections or connective joints that are elastic only within certain limits. With appropriate dimensioning of the elasticities of the individual elements of the cantilever arms, the suction grippers can describe an arcuate trajectory when the actuating means are operated, which are associated with the upper pulls of the cantilever arms. In this embodiment the suction grippers are nearly vertically aligned in a first position. Simultaneously the suction grippers are adjusted angularly. Thereby the central area of each lifted two-dimensional object is drawn up against the bottom side of the bridge. Meanwhile the peripheral areas are lifted from the stack by the suction grippers, whereby the lower bases of the suction grippers rotate outwards.
According to an alternative embodiment, at least one of the two connections between the suction gripper and the upper pull or the lower pull are formed flexible or articulated. Thereby a modified deformation behavior of the cantilever arms, and thus a modified trajectory of the suction grippers can be realized. In a side view the trajectory of the suction grippers may also resemble the dynamic upward and downward movements of wings, if necessary showing a greater curvature in the direction of the suction grippers. According to this embodiment the suction grippers are nearly vertically aligned in a first position. With appropriate dimensioning of the elasticities of the individual elements of the cantilever arms, the suction grippers can describe an arcuate trajectory when the actuating means are operated. The actuating means are associated with the upper pulls of the cantilever arms. Simultaneously the suction grippers are adjusted angularly. Thereby the central area of each lifted two dimensional object is drawn up against the bottom side of the bridge. Meanwhile the peripheral areas are lifted from the stack by the suction grippers, the lower bases of the suction grippers rotate outwards. With the upper pull that is connected to the suction gripper or the housing of the suction gripper by an articulated joint, the curvature of the cantilever arms can increase more at their free ends than in their other sections.
According to another possible embodiment of the inventive device the upper pull and the lower pull of each cantilever arm are interconnected between the bridge and the free end by at least one connecting bar. The connective joint between the at least one connecting bar and the lower pull can be formed largely bending resistant, bendable or articulated. Also the connective joint between the connecting bar and the upper pull can be formed largely bending resistant, bendable or articulated. Optionally two, three or more connecting bars can be arranged between the upper pull and the lower pull of each cantilever arm. Optionally a respective spring element can be assigned to the articulated connective joints to provide an automatic return to the starting position.
The connecting bars are constructed either extensive, columnar, scaffold-like or cross-piece like. They ensure that the pulling forces acting on the upper pull are transferred largely uniformly to the lower pull. The pulling forces are required for the lifting and simultaneous swiveling of the free ends of the cantilever arms and the attached suction grippers. The connecting bars transfer the tensile forces largely uniformly to the lower pull. In this case the lower pull exerts a supportive and reinforcing effect and prevents that the free ends of the cantilever arm bent outwardly too much without being simultaneously lifted to the desired extent. The distribution of forces over the upper pull onto the lower pull ultimately causes the desired deformation of the cantilever arm along its entire length. The local deformation behavior as well as the overall deformation behavior of the cantilever arms can be influenced and modified through the above-mentioned optional articulated joints that can be formed relatively flexible instead of a rigid linkage. It may possibly be useful to increasingly deform the cantilever arms in the direction of their free ends, while the sections close to the suspension are formed stiffer.
The mentioned connecting bars are not mandatory but optional. The elastic properties of the cantilever arms can be influenced in a suitable way by these connecting bars. Different embodiments are possible, for instance embodiments without any connecting bars between the upper pull and the lower pull or embodiments with just one connecting bar between the upper pull and the lower pull or embodiments with virtually any number of connecting bars positioned variably between the upper pull and the lower pull or embodiments with cross connected connecting bars between the upper pull and the lower pull.
It should be emphasized at this point that the upper pull and the lower pull must not be formed as flat components with struts arranged intermediately. Thus, an alternative embodiment can also provide that at least sections of the cantilever arms are formed as an integrated voluminous component, especially a composite component with defined elastic properties. If the term voluminous component is used in the present context, it can be used to describe a foamed component with or without apertures or openings, a honeycomb structure component or the like. The person skilled in the art knows other alternative variations that can be used to achieve the desired material properties and elastic properties and to ultimately achieve the desired deformation behavior of the cantilever arms, which is similar to the aforementioned “Fin-Ray” principle. Usually the term “Fin-Ray” effect is used to describe a phenomenon observed in fish. When the tail fins of certain fish are subjected to lateral pressure, they do not yield in the direction of the applied pressure. Instead they bulge out in the opposite direction; especially they bulge out in the direction from where the pressure is coming. In this context, the “Fin Ray” principle is modified in the following way: The fin-like motion of the suction grippers attached to the cantilever arms is not achieved by a pressure applied onto the top of the upper pull of the cantilever arms. Instead, the fin-like motion is achieved by the puling force that acts on the upper pull in a horizontal direction. For the function and the implementation of the desired movement and deformation behavior it is fundamentally irrelevant whether a component is used that consist of the clearly recognizable elements upper pull, lower pull and cross struts or whether a component is used whereby the single elements are combined in an integrated design.
Even when using such composite components two alternative embodiments of single piece components are possible. The first variation features a continuous lower pull and thereby a continuous shaping. The second variation shows a two-piece design with separate cantilever arms that are arranged symmetrically but require a central bearing at the bridge. The central bearing is usually located close to the lower pull or at the bottom side of the cantilever arms. The single-piece variation with a continuous lower pull is designed as an integrated component that comprises both cantilever arms arranged as a symmetric pair. The lower pull can either be connected centrally to the already described bridge or it can be supported on the bridge in a flying mount if required. In the single-piece variation at least the single-piece lower pull can act as a laminated spring, whereby the lower pull or the laminated spring seeks to return to its original extended position as soon as it is no longer attacked by deformation forces or pulling forces. It may also be advantageous in this variation if the upper pull, acting as a laminated spring, is additionally reinforced. The construction of the reinforced upper pull can resemble a multilayer laminated spring. Such an additional reinforcement can effectively prevent a failure of the component after extended operations, for example it can prevent a stress fracture.
The pulling means provide a horizontal or slanted upward pulling movement on the upper pull. The pulling means can be formed by nearly horizontal or inclined flat acting linear drives, which are preferably supported on the bridge. Such linear drives can be constructed for example as pneumatic cylinders or hydraulic cylinders, as electric motors or pulling drives. Preferably known components are used as suction grippers. The suction grippers are connected to a central vacuum supply via hose pipes. The suction properties of the suction grippers can be controlled individually or jointly. The bending movement of the lower pull can be adjusted by adjustable stopping elements, distance elements, spacers or the like, especially by spacers formed by compressed air cylinders. It must not be emphasized separately at this point that a synchronous deflection and control of the actuators is possible when using two single actuators to jointly control a pair of cantilever arms, provided a uniform deformation of both cantilever arms is desired. However asymmetric lifting movements and asymmetric deformation movements are equally possible. These asymmetric movements can be triggered by a controlled offset of the lifting movement of the actuators. In this case, any almost non-uniform deformation and thus any almost non-uniform lifting movement of the device according to the invention can be achieved by a selective activation of several actuators.
The device according to the invention typically shows a hanging arrangement and can for instance be moved by a horizontally and/or vertically adjustable extension arm. The complete suction gripper head with all its control components and movement components can be fixed to a central column, which is suspended from the end of the extension arm. If necessary the column can additionally be formed rotatable. Depending on the purpose this might not be required. The extension arm mentioned above can itself be suspended from a machine frame, a rotary column or the like, that may have a floor anchorage.
The invention furthermore relates to a method for receiving, holding and/or handling two-dimensional objects with at least two controllable suction grippers. The suction grippers are each mounted to free ends of cantilever arms. The cantilever arms are elastic at least in some sections or they are movable by swiveling movements. The cantilever arms are supported on a bridge and/or mounted on the bridge. The cantilever arms each comprise at least one lower pull and one upper pull, which meet at the free end of the cantilever arm. At the meeting point the upper pull and the lower pull are connected in a substantially rigid connection and arranged in the area of the bridge at a distance from each other. The lower pull is connected to the bridge at a defined position. The upper pull can be moved approximately parallel to the longitudinal extension direction of the cantilever arm by a actuating means or pulling means with at least one horizontal direction component. Through the pulling forced exerted on the upper pulls of the cantilever arms the suction grippers, which are virtually vertically aligned in a first position, describe an arcuate trajectory. Simultaneously the suction grippers are inclined at an angle. According to the invention the cantilever arms are each deformed by the pulling movement exerted on the upper pulls. Thereby the lower leg bends upward, meanwhile the upper leg shortens or moves towards the bridge. Thereby the free ends of the cantilever arms together with the attached suction grippers are bending upwards. Under the action of these actuating or pulling forces the entire cantilever arms together with the upper pulls and the lower pulls are elastically deformed. This is also known as “Fin-Ray”-principle.
The present invention overcomes some of the drawbacks that have been identified with the previously known lifting devices. One of the requirements is to produce production plants more cost-effectively. The device according to the invention and the appropriate method do not require stores for intermediate layers. They furthermore do not require a pre-separation of the stacked plates or other suitable retaining systems. Thereby the costs for such production plants can be reduced. The feeding of the production plant with stacked two-dimensional objects can be automated without any extra effort or increases in costs. The stacked two-dimensional objects are used as intermediate layers between layers of packs or as intermediate layers on pallets with several layers of beverage containers. In addition, the required placement accuracy of the stack is not very high, because the receiving and handling device is relatively tolerant regarding the exact positioning of the objects to be lifted.
In contrast to the aforementioned horizontal or diagonal pulling forces acting on the upper cantilever arm, the cantilever arms can optionally also be deformed by thrusting forces. Alternatively, the deformation of a pair of cantilever arms can also be caused by several pulling components, acting in a vertically upward direction. The upper pulls may be connected by an articulated joint and can be pulled upwards via a suitable pulling means. Thereby the above-mentioned “Fin-Ray” deformation can be achieved in a similar manner.
The cantilever arms can be made from various materials, optionally a combination of different materials can be used. The different materials can be connected by gluing, screwing, welding, plug-in connection systems etc. The connecting bars mentioned above may be arranged vertically or diagonally, whereby the rigid or articulated connective joints can be made separable or inseparable. The connecting bars can be formed as flat parts or as thin, preferably unfoldable struts made from any suitable material, for example made from injection-molded plastic. In an articulated joint or a similar connection a supporting spring can also be installed or integrated. The spring provides a sufficient restoring force which is required to return the cantilever arm from a deflected position back into the relaxed resting position.
Furthermore, the inventive handling device can be used in combination with other gripping tasks, for example with mechanical acting pallet grippings, with top frame grippers or the like. The additional grippers are preferentially arranged on the same frame, thereby creating an integrated design.
Another embodiment of the movable functional components of the inventive device for receiving, holding and/or handling two-dimensional objects can provide that the controllable suction grippers are individually or pair wise attached to the free ends of pivotally movable and deformable cantilever arms. The cantilever arms are for example mounted and connected to a bridge in a symmetrical arrangement or the cantilever arms are only supported on the bridge and/or the cantilever arms are supported on the bridge in a flying mount. The two-dimensional objects handled by the device according to the invention can be cardboard sheets, plastic sheets or metal sheets or twin-wall sheets made from plastics or cardboard, which are for instance used as intermediate layers between several stacked layers of beverage containers arranged on pallets etc. In such an embodiment the cantilever arms do not need to be formed elastically deformable. Instead the cantilever arms can be made from several stiff segments that are interconnected by articulated joints. The interaction of the interconnected plates allows a similar movement of the cantilever arms as in the embodiments described previously. In this further embodiment of the invention the cantilever arms can exert defined and superimposed lifting movements and pivoting movements by articulated movements of the plate segments.
The symmetrically and wing-like arranged cantilever arms each comprise a horizontally disposed, two-dimensional or plate-like lower pull. The cantilever arms furthermore comprise an upper pull that is inclined in an acute angle to the horizontal. The upper pull is also formed two-dimensional or plate-like. The lower pull and the upper pull meet at the free end of the cantilever arm and are preferably connected at this meeting point by an articulated joint. All existing articulated joints between the pivotally interconnected panel segments only allow swivel movements around axes which are parallel to each other. Usually the axes are oriented horizontally and transverse to the longitudinal extension direction of the lower pull. The entire lower pull extends over the two articulated connected, moveable, symmetrically arranged cantilever arms and is formed by a plurality of interconnected plate segments. Each of the two upper pulls is also formed by several panel segments interconnected by articulated joints. If required a central plate segment of the lower pull can be slightly shorter or longer than the two plate segments neighboring this central plate segment on both sides. Moreover, this central panel segment can be anchored to the bridge of the device, screwed to the bridge or just supported on the bridge in a so called flying mount. The two plate segments immediately adjoining the central plate segment of the lower pull on both sides are each articulated connected to the inner plate segments of the upper pulls by first coupling rods. The subsequently adjoining plate segments of the lower pull are articulated connected to other plate segments of the upper pulls by second coupling rods. Meanwhile the respective outermost plate segments of the upper pulls and respective outermost plate segments of the lower pull can be connected at their respective free ends by articulated connections. Alternatively only a rigid connection is possible between these outermost plate segments at the ends of the upper pulls and the lower pull. The two inner first coupling rods are each longer than the two outer second coupling rods. Thereby the overall wing-like shape of the arrangement according to one of the previously described embodiments is achieved. The location and functionality of the coupling rods largely corresponds to the location and functionality of the connecting bars of the previously described embodiments. The main difference is that the coupling rods are not connected rigidly but mounted on pivot pins. Thereby the coupling rods are each articulated connected to the corresponding plate segments of the upper pull or lower pull.
Optionally the coupling rods may be formed to simultaneously act as movement stops. This can be achieved by an appropriate shaping or profiling. The movement stops ensure that mutually facing surfaces of the plate segments of the upper pulls and the lower pulls meet with a defined maximum displacement. A deflection movement beyond the defined maximum displacement movement is not possible. A central plate segment of the lower pull of such a multi-piece gripping module formed by pivotally interconnected plate segments can be provided with an additional bridge segment. This bridge segment provides an articulated connection or support to a rigid bridge according to one of the previously described embodiments.
Some or each of the articulated joints between the plate segments may optionally include a spring element, for example a spring band partially enclosing the plate segments or something alike. Such spring bands couple neighboring plate segments. Therefore these neighboring plate segments are not fully and freely movable about the respective connecting axis. Instead the neighboring plate segments return into their initial or original position after each deflection. In this initial position the lower pull is stretched nearly straight and without any curvature. By using spring bands of different strength the spring forces and the restoring forces can be varied. Alternatively, the spring forces acting between plate segments interconnected by articulated joints can also be achieved by the use of different spring elements. For instance laminated spring elements can be integrated into the articulated joints, elastic pins can be positioned between the plate segments or other suitable means can be used.
Basically, even more embodiments are conceivable, which are not further explained here. Thereby the upper pulls can be formed by ropes, straps, link chains or something similar that are interconnected to the lower pull or lower pulls by suitable coupling elements either by articulated, elastical or at least partially rigid connections. If in the context of the present invention the definition elastic or articulated upper pulls is used, it comprises all variations with flexibly movable upper pulls that are for instance formed by girths, ropes etc.
The device according to the invention can optionally comprise a plurality of gripping modules, which can be controlled and moved independently. Thus, the device can comprise two gripping modules that are suspended from a common carrier, whereby the distance between the two gripping modules is adjustable and/or whereby the two gripping modules are controllable and movable independently of each other. Optionally the two gripping modules can also be controlled together. This is particularly useful for lifting and handling large plate-like components. The two gripping modules can also be moved independently of each other. This can be useful for example for the separate handling of correspondingly smaller plate-like components. Especially smaller plate-like components can be handled just by one gripping module, whereby a gripping module comprises up to four or more movable suction grippers. When handling smaller components, for instance so called intermediate layers for half-pallets; it is also possible to activate just one of the gripping modules. The other gripping module remains inactive as long as it is not needed.
Moreover, in such an embodiment according to the invention the distance between the two gripping modules may be adjusted. This can be achieved by the suspension of the gripping modules on slide guides, which are positioned on a common frame. For each gripping module the slide guides include a pair of horizontal axes. The mounting sections or the upper suspensions means of the gripping modules including their drive components and control components are mounted on the pair of horizontal axes. The entire arrangement is especially mounted slidably and can be moved along the axes in a horizontal direction. Each gripping module together with its whole suspension means and driving means can especially be moved in a horizontal direction about a certain distance along the frame and fixed in this new position. In this way the two gripping modules can be controlled independently. Furthermore the gripping modules can be adjusted to different sizes of intermediate layers for half-pallets or to different sizes of two-dimensional objects or the like. The above-mentioned adjustment or distance variation of the gripping modules can either be done manually or mechanically, for instance with an electric drive, a pneumatic drive or any other fluid drive.
Another option may provide that the inventive device is equipped with a pallet gripping system. The pallet gripping system is arranged on the common frame together with the at least one controllable gripping module. The pallet gripping system can be controlled independently of the gripping module and/or the pallet gripping system can be swivel mounted. This pallet gripping system can for example include suitable gripping arms attached to the frame of the device. The gripping arms enable the pallet gripping system to act as an intermediate layer gripper and/or pallet gripper. The at least two oppositely movable and/or pivotable gripping arms are preferably controllable and movable independently of the gripping modules for the intermediate layers or two-dimensional objects. An advantageous variation of such a pallet gripping system can for instance be combined with the distance adjustment of the pair wise arranged gripping modules, whereby the distance between the two gripping modules of a pair can be adjusted. The combination of the pallet gripping system and the pair of gripping modules can be achieved by an elongation of the already existing slide-guide-adjustment system that comprises appropriate holding means at each end. These holding means can for example be formed by metal clips, etc.
The holding means can comprise hooks, differently shaped retaining lugs or the like. The hooks etc. each point inwardly, especially facing each other and are arranged at the bottom side of the holding means. The holding means serve for engaging, receiving and handling the pallet.
In the following passages, the attached figures further illustrate exemplary embodiments of the invention and their advantages. The size ratios of the individual elements in the figures do not necessarily reflect the real size ratios. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention.
The same or equivalent elements of the invention are designated by identical reference numbers in
The schematic perspective view of
The extension arms 18 are formed elastically in such a way, that they cannot be moved in any arbitrary articulated way. Instead defined and superimposed lifting movements and arbitrary pivoting movements can be achieved by elastic deformations of the cantilever arms 18. The symmetrically arranged and wing-like cantilever arms 18 each comprise a horizontally arranged planar or sheet-like lower pull 22, a “pull” being a support movable by a force. The cantilever arms 18 furthermore comprise an upper pull 24 that is inclined from the horizontal plane at an acute angle. The upper pull 24 is also formed planar or sheet-like. The lower pull 22 and the upper pull 24 meet and are interconnected at the free end 16 of the cantilever arm 18. According to the embodiment shown in
Furthermore pairs of respective suction grippers 14 are arranged side by side at the free ends 16. The anchorage of the suction grippers 14 is not articulated but rigid or only slightly elastic to the extent of the elastic properties of the upper pull 24 and the lower pull 22. According to
Furthermore, the lower pull 22 and the upper pull 24 of each cantilever arm 18 are connected via a plurality of vertical, plane or sheet-like connecting bars 25. Like the lower pull 22 and the upper pull 24 the connecting bars 25 are preferably elastic to a certain extent, but at the same time resistant to folding and relatively rigid. According to a first embodiment the connective joints between the connecting bars 25 and the lower pull 22 or the upper pull 24 are not articulated but slightly elastic depending on the material properties of the firmly joined sections. Elastic, bendable or articulated connections are also possible between the upper pull 24 and the connecting bars 25 and/or between the lower pull 22 and the connecting bars 25. These mentioned connective joints and crossing points can be combined in any way, thereby it is possible to define the elastic properties and the exact deformation behavior of the cantilever arms 18 within broad limits.
According to the embodiment shown in
In the present context the term gripping module 17 is used for a module comprising a pair of symmetrically arranged cantilever arms 18, whereby each cantilever arm 18 consists of a lower pull 22, an upper pull 24 and at least one connecting bar 25. The schematic views of
A puller or pulling means 26 or an actuator or actuating means 28 is assigned to each of the upper pulls of the respective cantilever arms 18. The pulling means 26 or actuating means 28 are used for generating a horizontally directed pulling force, which is approximately parallel to the longitudinal extension direction of the respective cantilever arm 18. Usually the two actuating means 28 synchronously work against one another. In the illustrated embodiment, the actuating means 28 each comprise a linear drive 30, for example a hydraulic cylinder or a pneumatic cylinder or the like. The two linear drives 30 are horizontally anchored to the frame 12. The two linear drives 30 together with rod drive 32 each induce horizontally directed actuating movements onto the cross struts 34. One, two or more parallel anchorages of upper pulls 24 of one or more cantilever arms 18 can be attached to the cross struts 34. The view according to
The schematic diagrams of
The rigid connection between upper pull 24, lower pull 22 and suction gripper 14 at the free end 16 allows the desired and preferred trajectory of the suction gripper 14 according to
The suction grippers 14 are approximately vertically aligned in a first position. With appropriate dimensioning of the elasticities of the individual elements of the cantilever arms 18 and of the frictional forces of the individual articulated joints of the suction grippers 14 (see
The second embodiment shown in
As illustrated by the embodiments shown in
The detailed representation of
According to
The schematic view of
The schematic perspective view in
In particular, the
In the embodiments of the device according to the invention as shown in
The above-mentioned adjustment or distance variation of the gripping modules 17 can either be done manually or mechanically, for example, via an electric drive, a pneumatic drive or any other fluid drive.
The tactile elements 52 arranged on both sides of the suction grippers 14 also serve as hold-down elements. The duplicate tactile elements 52 are arranged in pairs. Because of their association with the gripping modules 17, the position of the tactile elements 52 can be adjusted together with the position of the gripping modules 17. The tactile elements 52 or hold-down elements serve to facilitate the separation of the two-dimensional objects 38 before lifting, for example the separation of intermediate layers of plastic or cardboard or they facilitate the separation of intermediate layers for half pallets before lifting.
The components of the device 10 not shown in
In this embodiment the cantilever arms 18 of the gripping module 17 are not elastically deformable. Instead the cantilever arms 18 are made of several rigid plate segments 60 interconnected by articulated joints. The interacting plate segments 60 allow a similar movement of the cantilever arms 18 as shown in the previously described embodiments. The defined and superimposed lifting movements and pivoting movements according to
The entire lower pull 22 extends over two articulated movable, symmetrical cantilever arms. According to the shown embodiment the entire lower pull 22 is formed by seven interconnected plate segments 60. Each upper pull 24 is formed by three plate segments 60, which are interconnected by articulated joints. Of course other arrangements are conceivable, whereby the lower pull 22 is formed by more than seven or less than seven plate segments 60 and whereby the upper pull 24 is formed by more than three or less than three plate segments 60. The central plate segment 62 of the lower pull 62 can be shorter or longer than the neighboring plate segments 60, if required. The central segment 62 can optionally be anchored to the bridge 20 of the device 10 (see
The two plate segments neighboring the central plate segment 62 of the lower pull 22 are each connected via an articulated joint to the inner plate segments 60 of the upper pulls 24 by first coupling rods 64. The subsequently neighboring plate segments 60 of the lower pull 22 are each connected via an articulated joint to the middle plate segments 60 of the upper pulls 24 by second coupling rods 66. The outermost plate segments 60 of the upper pulls 24 and the outermost plate segments 60 of the lower pull 22 are each interconnected via articulated joints at the free ends 16 of the cantilever arm. The two inner first coupling rods 64 are each longer than the two outer second coupling rods 66. Thereby a wing-like arrangement is formed as shown in
Some or each of the joints in between the plate segments 60 and 62 can comprise spring elements. This in indicated in
In the lower pull 22 the base section of each spring band 68 lies on the upper side of each neighboring outer plate segment 60. If a plate segment 60 gets pulled upwards, a downward acting restoring force is created. The hook-shaped ends of the spring band 68 legs are hooked to the opposite sides of the subsequently arranged inner plate segments 60 or the central plate segment 62. The appropriate orientation of the spring bands 68 in the upper pulls 24 depends on the desired direction of the restoring forces. Optionally, the hook-shaped ends of the parallel legs can be anchored to the sides of the plate segments 60 in such a manner that they can not twist in the receiving openings 70. Thereby the desired restoring action of the spring elements is achieved
Other spring elements can be used to achieve the spring forces between the plate segments, which are connected by articulated joints. For instance laminated spring elements integrated into the articulated joints or elastic pins integrated between the plate segments 60 or other suitable means can be used.
The respective suction grippers 14 are arranged pair wise beside each other at the free ends 16 of the cantilever arms 18. The connection between the suction grippers 14 and the free ends 16 is not articulated but rigid. The grippers 14 are connected to the free ends 16 by a mounting plate 15 that is attached to the outermost plate segment 60 of the lower pull 22.
As in the embodiments described above but not shown in
The side view of
The entire lower pull 22 extends over the two articulated movable, symmetrical cantilever arms 18. According to the shown embodiment the entire lower pull 22 is formed by five interconnected plate segments 60. Each of the two upper pulls 24 is formed by two plate segments 60, which are interconnected by articulated joints. The central plate segment 62 of the lower pull 22 can be shorter or longer than the neighboring two plate segments 60 if required. The central segment 62 can optionally be anchored to the bridge 20 of the device 10 (see
The two plate segments 60, adjoining the central plate segment 62 of the lower pull 22 on both sides, are interconnected to the plate segments 60 of the upper pulls 24 by fourth coupling rods 76. The fourth coupling rods 76 are articulated connected to the outer articulated joints, which are located between the plate segments 60 adjoining the central plate segment 62 of the lower pull 22 and the outermost plate segments 60 of the lower pull 22 as can be seen in
Each of the two upper pulls 24 of the respective cantilever arm 18 comprises a pulling means or an actuating means for generating a horizontally directed pulling force approximately parallel to the longitudinal extension of the cantilever arm 18. This has been shown for the embodiments described previously, but is not shown in
Other embodiments not shown here are also possible, whereby the upper pulls 24 are made from ropes, belts, link chains or the like. The upper pulls 24 can either be connected to the lower pull 22 elastically or by articulated joints or at least partially rigid.
The schematic perspective view of
An embodiment depicted in
If the gripping arms 82 are not in use, they can either be at least partially intertwined as shown in
The schematic perspective view of
Basically other variations of gripping systems are conceivable, which are covered by the inventive concept. Especially other variations apart from the pivotable pallet gripping systems 84 (
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 008 848 | Jan 2011 | DE | national |
| 10 2011 084 830 | Oct 2011 | DE | national |
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| Number | Date | Country | |
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| 20120181740 A1 | Jul 2012 | US |
