Abstract:
The invention relates to a tray sealer comprising a gripper device with two gripper arms, a supply device for unsealed trays, a removal device for sealed trays and a sealing device. Each gripper arm can comprise a coupling device that is configured to hold a first tray gripper for supplying trays into the sealing device and a second tray gripper for removing trays from the sealing device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application claims priority to European Patent Application Number 15183808.3 filed Sep. 4, 2015, to Andreas Mader, et al., currently pending, the entire disclosure of which is incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The invention relates to a tray sealer. 
       BACKGROUND OF THE INVENTION 
       [0003]    DE 10 2008 030 510 A1, DE 10 2010 027 211 A1, and DE 10 2012 015 401 A1 disclose tray sealers with tray grippers which are integrally configured and, during their movement in the direction of transport, convey several unsealed trays into a sealer. The tray grippers also convey trays sealed with a top film out of the sealer. Such tray sealers are equipped with sealing tools that, when viewed in the direction of production, become increasingly longer to further enhance the performance of these machines The tray grippers also become correspondingly longer. With an extension of the sealing tool, for example, from 800 mm to 1100 mm, the tray gripper must, for example, be extended from 1600 mm to 2200 mm. Different tray grippers and sealing tools are commonly used for different tray shapes. Tray grippers and sealing tools, when not being used in a tray sealer, are mounted on tool trolleys which are frequently moved to special rooms outside the production area of the tray sealer for maintenance or for cleaning purposes. The length of the tray grippers can pose an obstacle when driving through a door. 
         [0004]    The length of such tray grippers can also lead to problems in adjusting them to match the trays which are provided on a supply belt for being transferred, the trays in the sealing tool, and the trays which are deposited on a removal belt. Adjustment of the tray gripper becomes increasingly complicated with an increase in its length, especially with tray sealers in which the transport level of the supply belt, the removal belt and the depositing level on a sealing tool lower part form no common level. 
       SUMMARY OF THE INVENTION 
       [0005]    One object of the present invention is to provide an improved tray sealer. 
         [0006]    The tray sealer according to one embodiment of the present invention comprises a gripper device with two gripper arms, a supply device for unsealed trays, a removal device for sealed trays and a sealing device. Each gripper arm can comprise a coupling device that is configured to hold a first tray gripper for supplying trays into the sealing device and a second tray gripper for removing trays from the sealing device. Due to a separation of the two gripper arms, which are intended for different functions and are in different spatial workspaces, the length as compared to prior art tray grippers is approximately halved so that tool lengths above 1200 mm, for example, are possible. The tray grippers can therefore be better handled both during exchange and during transportation on a tool exchange carriage. 
         [0007]    At the same time, the present invention may address problems associated with differing levels of the supply belt, removal belt and sealing tool lower part. For example, in one embodiment of the present invention, the first tray gripper needs only to be adjusted with respect to the supply belt and the sealing tool lower part, and the second tray gripper needs only to be adjusted with respect to the sealing tool lower part and the removal belt. 
         [0008]    The first and the second tray gripper may each be attachable to the coupling device of the gripper arm by way of a first and a second holding element. This may permit connection of the tray gripper to the gripper arm without play and in a torsion-resistant manner. Preferably, this attachment is carried out without a wrench. 
         [0009]    In one embodiment of the present invention, at least one holding element is adjustable at the tray gripper in such a manner that the tray gripper can be oriented with respect to a first, a second and/or a third transport level. The tray gripper can therefore be adjusted in its orientation relative to the position of the trays. Two tray grippers arranged and interacting on both sides of a lane of successive trays can be adjusted relative to each other in such a manner that all trays to be picked up out of a group of trays are gripped with approximately the same force. The three transport levels can be oriented parallel to each other, but have different vertical distances. The first tray grippers can be oriented relative to the first and the second transport level, and the second tray gripper can be oriented relative to the second and the third transport level each in an optimized manner. 
         [0010]    In one embodiment, at least one holding element is adjustable at the tray gripper in two mutually perpendicular axes in such a manner in order to be able to adjust the tray gripper in a vertical plane and a horizontal plane. 
         [0011]    The holding elements can be configured such that torques, being generated by forces acting upon the tray gripper, are absorbed by the coupling device so that the first and the second tray grippers, respectively, of a common side, together with the two corresponding tray grippers of a second opposite side, generate a symmetry of forces within the gripper device during the process of gripping and transporting the trays. 
         [0012]    In one embodiment, two holding elements are provided for every tray gripper and interact as a two-point attachment with the coupling device of the gripper arm, preferably without play. 
         [0013]    In another embodiment, a single holding element is provided and configured to be wedge-shaped and/or prism-shaped to allow for a connection without play of the tray gripper to the coupling device. 
         [0014]    The first and the second tray grippers may each be connectable to their associated coupling device in an independently detachable manner. 
         [0015]    Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description. 
     
    
     
       DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0016]    In the following, an advantageous embodiment of the invention is further illustrated using a drawing, where: 
           [0017]      FIG. 1  is a perspective view of a tray sealer according to one embodiment of the present invention; 
           [0018]      FIG. 2  is a perspective view of a gripper device according to one embodiment of the present invention; and 
           [0019]      FIG. 3  is a perspective view of a coupling and a holding element according to one embodiment of the present invention. 
       
    
    
       [0020]    Same components are designated with the same reference numerals throughout the figures. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purposes of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures. 
         [0022]    The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled. 
         [0023]      FIG. 1  shows a tray sealer  1  according to one embodiment of the present invention with a supply device in the form of a supply belt  2 , a sealing device  3  and a removal device in the form of a removal belt  4 , which are arranged consecutively in this order in a direction of production P. Furthermore, tray sealer  1  can comprise a machine frame  5 , a film feeder  6  and a film trim winder  7 . A gripper device  8  with two gripper arms  9  and respectively a first  10  and a second tray gripper  11  may be provided on both sides in the direction of production P for transporting trays  12 . In one embodiment, an operator can influence all processes of tray sealer  1  via an operating device  13 . 
         [0024]    During operation, trays  12  may be transported on the supply belt  2  and on the removal belt  4  into and out of the sealing device  3 , respectively. In the sealing device, trays  12  are, for example, filled with a product, evacuated, flushed with gas, sealed with a top film  14  and cut. The trimmed film residue, also referred to as residual film lattice, may be wound onto film trim winder  7 . 
         [0025]    As best illustrated in  FIG. 1 ,the upper portion of supply belt  2  forms a first transport level E 1 , a sealing tool lower part  3   a  of sealing device  3  for depositing trays  12  forms a second transport level E 2 , and the upper portion of removal belt  4  forms a third transport level E 3 . 
         [0026]    Transfer of trays  12  between the supply belt  2 , sealing device  3  and removal belt  4  can be performed by gripper device  8 , which is illustrated in  FIG. 2  in more detail. 
         [0027]      FIG. 2  shows the gripper device  8  according to one embodiment of the present invention with two gripper arms  9  movable in and opposite to the direction of production P and arranged laterally relative to trays  12  to be transported. The gripper arms  9  can each comprise a coupling device  15  in their lower region. The first tray gripper  10  and the second tray gripper  11  may be respectively provided at each coupling device  15  consecutively in the direction of production P. 
         [0028]    The two first tray grippers  10  may be configured such that they pick up between them a group of five trays  12  from supply belt  2  and transport the group to sealing device  3 . The second tray grippers  11  may be at the same time be configured such that they supply the group of five trays  12 , that were previously sealed with a top film  14  to a become a finished package, from the sealing device  3  to the removal belt  4 . 
         [0029]    A pivoting motion of gripper arms  9  toward each other or away from each other about pivot axes  9   a,  respectively, allows for the gripping of trays  12  from the supply belt  2  or in the sealing device  3  or for depositing trays  12  in the sealing device  3  or onto the removal belt  4 . 
         [0030]    Both first tray gripper  10 , as well as second tray gripper  11 , can each comprise a first  16  and a second holding element  17  by use of which tray grippers  10 ,  11  are attachable to and detachable from coupling device  15  without a wrench. 
         [0031]      FIG. 3  shows a detail of coupling device  15  in an enlarged view with a holding element  16  of first tray gripper  10  in a detached state. Holding element  16  can comprise two holding bolts  20   a  and  20   b  which are mounted at a fixed distance relative to each other on an adjustment plate  21 . Adjustment plate  21  may be adjustably attached to tray gripper  16  by way of a bolt connection  22 . Coupling device  15  can comprise a support  23  which has two U-shaped openings  24  for receiving holding bolts  20   a,    20   b.  For this purpose, holding bolts  20   a,    20   b  may have a reduced diameter D at their central portion which is provided for U-shaped opening  24  in a precise fit. After inserting holding bolt  20   a,    20   b  into support  23 , a spring plate  25  can ensure a reliable connection of tray gripper  16  to coupling device  15  in that spring plate  25  may enclose a holding bolt  20   a  in part and at the front end. For detaching, spring plate  25  merely has to be manually pushed away from holding bolt  20   a  so that tray gripper  16  can be removed. 
         [0032]    From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting. 
         [0033]    The constructions and methods described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.