Patent Publication Number: US-10773909-B2

Title: Apparatus for feeding a plurality of flat elements lying flat on one another, in particular carton blanks, to a packaging apparatus

Description:
The invention relates to an apparatus for feeding a plurality of planar elements, resting against on one another, in particular carton blanks, to a packaging apparatus, comprising a first feed portion having a conveying means, the conveying surface of which, intended for supporting the planar elements, is formed of a material that has a specified coefficient of static friction with respect to the interaction with the planar elements, and comprising a second feed portion that slopes downwards towards the packaging apparatus, the inclination of the first feed portion and the inclination of the second feed portion towards the packaging apparatus being different from one another. 
     It should already be noted at this point that, within the meaning of the present invention, the term “feed portion” denotes a longitudinal portion of the feed apparatus that has a specified inclination, over the entire length thereof, towards the packaging apparatus. Furthermore, for the sake of simplicity, the invention will be explained in the following with reference to the example of carton blanks. However, no limitation of any kind can be derived therefrom. 
     Feed apparatuses (not of the type in question) are known from the prior art which comprise a single feed portion that slopes downwards towards the packaging apparatus. In this case, the conveying surface of the conveying means that extends over the entire length of said feed portion is formed of a material, the coefficient of static friction of which with respect to the carton blanks is selected such that the carton blanks can be conveyed towards the packaging apparatus in a manner substantially free of slip relative to the conveying surface. If it is taken into account that the length of the feed portion is generally dimensioned such that the feed portion can receive sufficient carton blanks for the loading of the packaging apparatus to be ensured for several minutes, it is clearly apparent that the gravity-induced pressure (back pressure) that the entirety of the carton blanks exerts on the adjacent carton blanks on the packaging apparatus, owing to the inclination of the feed portion, can reach a value that makes it more difficult, and sometimes even impossible, to separate the carton blanks using a gripper unit, generally comprising a vacuum gripper, at the start of the packaging apparatus. This results in undesired downtimes of the packaging apparatus. 
     In order to overcome this problem, feed apparatuses (of the type in question) have already been proposed which comprise a substantially horizontal first feed portion comprising a conveying means, and a second feed portion that slopes downwards towards the packaging apparatus and does not comprise a conveying means. This arrangement makes it possible to significantly reduce the back pressure, since the carton blanks arranged in the horizontal first feed portion cannot contribute to said pressure. However, it has been found in practice that said feed apparatuses are prone to canting of the adjacent carton blanks at the end of the second feed portion of the packaging apparatus. In this case, it should be noted that, also according to the invention, the carton blanks are preferably fed to the packaging apparatus in an orientation in which a peripheral edge of said blanks stands upright on the first feed portion and the second feed portion. 
     The object of the present invention is that of remedying this situation. 
     This object is achieved according to the invention by a feed apparatus of the type mentioned at the outset, in which the second feed portion comprises a further conveying means, the conveying surface of which, intended for supporting the planar elements, is formed of a material, the coefficient of static friction of which with respect to the interaction with the planar elements, in particular carton blanks, has a lower value than the material of the conveying means of the first feed portion. 
     Owing to the low coefficient of static friction of the conveying surface of the further conveying means, the peripheral edge of the carton blanks can slide along on said conveying surface, making it possible to achieve the advantages of the generic prior art even in the case of the feed apparatus according to the invention. At the same time, despite the low coefficient of static friction, the carton blanks nonetheless receive a conveying momentum, in each conveying cycle, which, as has been proven strikingly in practice, is sufficient for counteracting canting of the carton blanks. 
     It is advantageously possible for the coefficient of static friction of the conveying surface of the further conveying means to be selected such that the static friction between the conveying surface and the carton blanks is overcome during a conveying cycle of the further conveying means, such that slip results between the conveying surface and the carton blanks. 
     For example, the conveying surface of the conveying means of the first feed portion may be formed of polyurethane, and/or the conveying surface of the further conveying means of the second feed portion may be formed of Teflon. Alternatively, the conveying surface of the conveying means of the first feed portion could be formed of elastomer, natural rubber, a polyamide woven fabric or silicone, and the conveying surface of the further conveying means of the second feed portion could be formed of PVC or a steel coating. 
     In order to achieve mutually coordinated operation of the two conveying means, it may further be possible for the conveying means of the first feed portion and the further conveying means of the second feed portion to be associated with a common drive unit. In this case, in order to allow for the drive force of the common drive unit to be transferred between the two conveying means, it may be possible for the two conveying means to be drivingly interconnected at the transition from the first feed portion to the second feed portion. This can be achieved for example in that a deflection unit is arranged at the transition from the first feed portion to the second feed portion, which deflection unit deflects both the conveying surface of the conveying means of the first feed portion and the conveying surface of the further conveying means of the second feed portion. 
     According to a development of the invention, one conveying means and/or the further conveying means comprises at least one conveyor belt which is formed by a toothed belt for example. In this case, the surface of the at least one conveyor belt that faces the carton blanks forms the conveying surface or a portion of the conveying surface of one conveying means or of the further conveying means. 
     In this connection, it is furthermore possible for the deflection unit to comprise a rotatable shaft on which at least one deflection wheel associated with the conveyor belt of the first feed portion, as well as a deflection wheel associated with the further conveying means of the second feed portion, are arranged. Alternatively, the two deflection wheels may also be formed integrally with one another and be rotatably mounted by means of a common pivot bearing. In the case of toothed belts being used, the deflection wheels can advantageously be formed as gear wheels. In this case, the toothed belt/gear wheel drive combination allows for particularly precise driving of one conveying means and/or of the further conveying means. 
     According to a development of the invention, the feed apparatus comprises at least two feed units, each of which comprises at least one conveyor belt associated with the first feed portion, and a conveyor belt associated with the second feed portion, said conveyor belts being arranged on a common carrier. Advantageously, the conveyor belts of each feed unit are of the same width. 
     In order to be able to ensure disruption-free transition of the carton blanks from the first feed portion to the second feed portion, it is advantageous for the conveyor belts to be arranged adjacently to one another at the transition from the first feed portion to the second feed portion. In this case, it is preferable for the spacing between the two conveyor belts to be smaller than the width of said belts or smaller than the width of the narrower of the two conveyor belts. 
     The feed apparatus may furthermore comprise a frame, on which the at least two feed units are arranged so as to be displaceable relative to one another transversely to the conveying direction. This makes it possible to use the feed apparatus for planar elements, in particular carton blanks, of different widths. 
     Finally, it should be noted that, as is known per se from the prior art, the first feed portion can advantageously extend so as to be substantially horizontal. This makes it possible for said feed portion to be of any desired length without a back pressure being generated thereby that could act on the adjacent carton blanks at the end of the second feed portion of the packaging apparatus. 
     Furthermore, the second feed portion may have an angle of inclination of between approximately 5° and approximately 40° relative to the horizontal, positive angle values indicating a progression of the second feed portion that slopes downwards in the conveying direction, towards the packaging apparatus. 
    
    
     
       The invention will be explained in greater detail in the following, on the basis of an embodiment and with reference to the accompanying drawings. In the drawings: 
         FIG. 1  is a perspective view of a feed apparatus according to the invention; 
         FIG. 2  is a plan view of the feed apparatus according to the invention; 
         FIG. 3  is a side view of the feed apparatus according to the invention; and 
         FIG. 4  is a schematic view of the structure of the conveyor belts of the feed apparatus according to the invention. 
     
    
    
     In  FIGS. 1 to 3 , a feed apparatus according to the invention is denoted very generally by  10 . 
     Said apparatus is used for feeding a plurality of planar elements  12  (see  FIG. 3 ), resting flat against one another, in particular carton blanks, to a packaging apparatus, the position of which is indicated merely in a highly schematic manner in  FIG. 3  by the reference sign V. 
     The feed apparatus  10  comprises two feed units  14  and  16  which are arranged so as to be mirror-symmetrical with respect to a longitudinal central plane E (see  FIG. 2 ) of the feed apparatus  10 , but are otherwise designed identically. The design of the feed units  14  and  16  will therefore be described in the following merely with reference to the example of the feed unit  14 . 
     The feed unit  14 , and thus also the feed apparatus  10 , comprises two feed portions  18  and  20 , each of which comprises a conveyor belt  22  and  24 , respectively, which are both preferably formed by a toothed belt. In this case, the conveyor belt  22  is driven by a drive means  26  which can be seen most clearly in  FIG. 3  and acts on a drive wheel  28 . 
     In the embodiment shown, the drive means  26  is formed by a piston-cylinder unit  27  which, in  FIG. 3 , rotates the drive wheel  28  in an anti-clockwise direction, by a specified angle, by means of a lever  32  connected to the piston rod  30 , upon each actuation, and thus moves the upper run  22   a  of the conveyor belt  22  by a specified distance in the conveying direction F, i.e. towards the packaging apparatus V. Upon a return stroke of the piston-cylinder unit  27 , a free wheel (not shown) ensures that the drive wheel  28  pauses in the position thereof. 
     A deflection wheel  34  for the conveyor belt  22  is arranged at the transition from the first feed portion  18  to the second feed portion  20 . Said deflection wheel  34  is arranged on the same shaft as a deflection wheel  36  of the second conveyor belt  24 . In this case, the two deflection wheels  34  and  36  are interconnected for conjoint rotation, such that the drive movement of the conveyor belt  22  can be transmitted to the conveyor belt  24 . As a result, it is not necessary to provide a separate drive means for the conveyor belt  24 . However, for the sake of completeness the deflection wheel  38  of the second conveyor belt  24  should also be mentioned, which wheel is arranged on the end of the feed apparatus  10  that faces the packaging apparatus V. 
     It should also be noted at this point that the surface  22   a   1  of the upper run  22   a  of the conveyor belt  22 , and the surface  24   a   1  of the upper run  24   a  of the conveyor belt  24  each form a conveying surface on which the carton blanks  12 , specifically, as can be seen from  FIG. 3 , the peripheral edges thereof, stand upright during operation of the feed apparatus  10 , i.e. on the route to the packaging apparatus V. 
     Both conveyor belts  22  and  24  may be formed as toothed belts, in which case the deflection wheels  28 ,  34 ,  36  and  38  are formed as gear wheels. As shown schematically in  FIG. 4 , both conveyor belts  22  and  24  comprise a first layer  40  which provides contact with the deflection wheels  28 ,  34 ,  36  and  38  and, when the conveyor belts are formed as toothed belts, also carries the toothing  42  thereof. Furthermore, both conveyor belts  22  and  24  comprise a second layer  44  which comes into contact with the carton blanks  12 . According to the invention, the second layer  44  of the conveyor belt  22  is formed of a material that has a higher coefficient of static friction than the material of the second layer  44  of the conveyor belt  24 . For example, the second layer  44  of the conveyor belt  22  may be formed of polyurethane, while the second layer  44  of the conveyor belt  24  may be formed of Teflon. 
     As can be seen in particular in  FIG. 3 , the first feed portion  18  extends so as to be substantially horizontal, while the second feed portion  20  slopes downwards in the conveying direction F. In this case, the angle of inclination a is preferably between approximately 5° and approximately 40°. 
     It should be noted at this point that the conveyor belts  22  of the first feed portions  18  of the two conveying units  14  and  16 , and the further elements required for driving said conveyor belts  22 , together form a first conveying means  46  of the feed apparatus  10 , while the conveyor belts  24  of the second feed portions  20  and the further elements required for driving said conveyor belts together form a second conveying means  48  of the feed apparatus  10  (see  FIG. 2 ). 
     As can be seen in particular in  FIG. 2 , the two conveyor belts  22  and  24  are arranged so as to be directly adjacent to one another, in the region of the transition from the first feed portion  18  to the second feed portion  20 . In this case, however, said belts preferably do not rest on one another, since this would lead to wear, but instead are at a spacing from one another that is smaller than the width b of the two conveyor belts  22  and  24  (see  FIG. 2 ). 
     It should furthermore be noted that the two feed units  14  and  16  are formed as self-contained modules which are arranged on a frame  50  of the feed apparatus  10  so as to be adjustable relative to one another in the transverse direction Q, i.e. in the direction orthogonal to the conveying direction F. For this purpose, all the components of the feed units  14  and  16 , i.e. the conveyor belts  22  and  24  and all the elements required for driving said belts, are arranged on a common carrier  52 .