SYSTEM AND METHOD OF FEEDING A PACKAGING MACHINE

Abstract: A feed system for feeding a packaging machine, wherein a first and a second conveying system (12, 13), parallel to each other and having respective first and second pushers (60a, 60b), receive stacks of objects at an input and feed the stacks to an output (1b) of the feed system connected to a packaging machine. An electronic control unit regulates the movement of the first and second conveying system so that each pusher is brought gently into contact with a respective stack, and so as to ensure a continuous stream of stacks of objects to the output of the feed system.

Description: SYSTEM AND METHOD OF FEEDING A PACKAGING MACHINE TECHNICAL FIELD The present invention relates to a system and method of feeding a packaging machine . BACKGROUND ART Packaging machine feed systems are known wherein a conveying system travels between an input for receiving a number of stacks of objects, and an output for feeding the stacks sequentially to the input of a packaging machine, which forms adjacent groups of stacks and arrange them in a package (e.g. the groups are wrapped in a tubular package of plastic material) . Known conveying systems normally comprise a number of pushers movable with respect to a supporting surface and spaced in a (normally straight) feed direction, and each of which is brought into contact with a respective stack to push it along the supporting surface to the output of the feed system. The stacks of objects may be fed downwards to the input, i.e. released by gravity from an unloading station located over the supporting surface, or may be fed laterally, i.e. pushed onto the supporting surface in a direction crosswise to the feed direction. Whichever the case, in known feed systems, the stacks are fed onto the supporting surface while the pushers are moving, and impact between the pusher and the respective stack is severe enough to produce a series of drawbacks, including: damage to the objects in the stack - especially when the objects are made of crumbly material, such as baked food products (biscuits, cakes, wafers) ; damage to the stack itself, which is pushed out of shape; and destruction of the stack, so that the objects topple onto the supporting surface . All of which drawbacks obviously impair, if not prevent, performance of the follow-up packaging process. DISCLOSURE OF INVENTION It is an object of the present invention to provide a feed system designed to eliminate the drawbacks typically associated with known systems . More specifically, it is an object of the present invention to prevent sharp contact between the pushers and stacks, so as to safeguard the structure of the stack and/or prevent damage to the objects. According to the present invention, there is provided a system for feeding a packaging machine, as claimed in Claim 1. The present invention also relates to a method of feeding a packaging machine, as claimed in Claim 10. BRIEF DESCRIPTION OF THE DRAWINGS A preferred, non-limiting embodiment of the invention will be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a simplified side view of a system for feeding a packaging machine, in accordance with the present invention and in a first operating position; Figure 2 shows the Figure 1 system in a second operating position; Figure 3 shows the Figure 1 system in a third operating position; Figure 4 shows a view in perspective of a portion of the Figure 1 system; Figure 5 shows a cross section (plane A-A in Figure 1) of a central portion of the Figure 1 system; Figure 6 shows a cross section (plane B-B in Figure 1) of a- first end portion of the Figure 1 system; Figure 7 shows a cross section (plane C-C in Figure 1) of a second end portion of the Figure 1 system; Figure 8 shows operations performed by the feed system according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Number 1 in Figure 1 indicates as a whole a system for feeding a packaging machine . More specifically, feed system 1 receives stacks 4 of objects 5 at an input la, and feeds stacks 4 in a straight feed direction D to an output lb of feed system 1 where stacks 4 are fed sequentially to a known packaging machine 7, which forms stacks 4 into groups and packs the groups of stacks in respective packages (not shown) to pack objects 5. Preferably, though not necessarily, objects 5 comprise substantially flat (e.g. disk- or parallelepiped-shaped) food products arranged one on top of the other to form stacks of two-four objects. Examples of flat food products are baked food products • such as - cakes, tarts, biscuits, snacks and wafers, though feed system 1 may obviously be used for feeding objects 5 of any stackable shape . Each object 5 may also be individually wrapped, e.g. in a tubular sheet wrapping (not shown) , so that each stack 4 is defined by individually wrapped objects 5, e.g. a number of (e.g. three) individually wrapped disk- shaped cakes . Objects 5 are made in a production device (e.g. an oven (not shown) for food products) and are fed to a known stacking device 10 for forming a number of stacks 4 of objects 5, each stack comprising the same number of objects 5 (in the example shown, each stack 4 comprises three objects 5) . Each group of stacks 4 supplied by device 10 is also known as a batch. Feed system 1 comprises a first, straight linear conveying system 12 and a second straight linear conveying system 13 (Figures 4 and 5) extending parallel to each other between input la and output lb. More specifically, feed system 1 comprises a bed (not shown) supporting an elongated supporting structure 15 (Figure 5) defined by an elongated, parallelepiped- shaped central member 16, from opposite faces 16a, 16b of which extend pairs of flat walls 17a, 17b, 18a, 18b perpendicular to respective faces 16a, 16b. Walls 17a and 18a are parallel to a first vertical plane PI, and walls 17b and 18b are parallel to a second vertical plane P2 parallel to plane PI . Walls 17a and 18a define respective first straight elongated seats 21a, 21b extending parallel to each other in direction D, and walls 17b and 18b define respective second straight elongated seats 22a, 22b also extending parallel to each other in direction D. First conveying system 12 comprises a first powered chain 30 extending between toothed end pulleys 31, 32 (Figure 1) and comprising a straight top portion 30a housed and guided inside seat 21a, and a straight bottom portion 30b housed and guided inside seat 21b. Similarly, second conveying system 13 comprises a second powered chain 34 extending between toothed end pulleys 36, 37 (Figures 6 and 7) and comprising a straight top portion 34a housed and guided inside seat 22a, and a straight bottom portion 34b housed and guided inside seat 22b. Figure 6 shows pulleys 31 and 36 located at the end of elongated supporting structure 15 away from packaging machine 7 and close to stacking device 10. More specifically, pulleys 31 and 36 are idle- and supported on respective bearings 39, 40 fitted to supporting structure 15. Figure 7 shows pulleys 32 and 37 located at the end of elongated supporting structure 15 close to packaging machine 7. More specifically, pulley 37 is connected to a first end of a tubular sleeve 42, a second end of which is fitted with a toothed pulley 43 rotated, via a toothed belt 44, by an electric motor 45 fitted to the bed. Tubular sleeve 42 is also fitted, via the interposition of two ball bearings 46, to a metal tube 47 projecting from a wall 48 of the bed, so that power is transmitted from motor 45 to pulley 37 to drive chain 34. Pulley 32, on the other hand, is located at a first end of a shaft 49 housed coaxially inside tubular sleeve 42 and connected to tubular sleeve 42 via the interposition of two bearings 50. A second end of shaft 49 projects from tubular sleeve 42 and is fitted to a toothed pulley 51 connected by a toothed belt 52 to the output shaft of an electric motor 53 fitted to the bed, so that power is transmitted from motor 53 to pulley 32 to drive chain 30. First chain 30 has a first number of first pushers 60a (Figures 4 and 5) equally spaced along chain 30 and movable in direction D. More specifically, each pusher 60a comprises a substantially L-shaped central body 61 connected to a link of chain 30 by a respective pin 62 extending from a central portion of the L-shaped body and perpendicular to plane PI and to the traveling direction D of chain 30. Each pusher 60a also comprises a rectangular supporting wall 64 carried by one leg of the L-shaped body and perpendicular to direction D and to planes PI, P2. Each central body 61 is housed between chains 30 and 34, and is movable along a plane P3 (Figure 5) located between, parallel to, and equidistant from planes PI, P2, so that supporting walls 64 are also movable in direction D while remaining perpendicular to planes PI and P2. Second chain 34 has a second number of second pushers 60b equally spaced along chain 34 and movable in direction D. More specifically, each pusher 60b has the same structure as pushers 60a and comprises a substantially L-shaped central body 61b connected to a respective link of chain 34 by a respective pin 62b extending from a central portion of the L-shaped body and perpendicular to plane P2 and to the traveling direction D of chain 34. Each pusher 60b also comprises a rectangular supporting wall 64b perpendicular to direction D and to planes PI, P2. Each central body 61b is housed between chains 30 and 34, and is movable along plane P3, so that supporting walls 64b are also movable in direction D while remaining perpendicular to planes PI and P2. Pushers 60a and 60b are therefore movable along the same plane P3, but are prevented from coming into contact with one another by only extending along portions of respective chains 30 and 34, and by chains 30 and 34 being so controlled that the portions of chains 30, 34 supporting pushers 60a and 60b are never positioned alongside each other. System 1 also comprises a rectangular supporting surface 70 (Figure 5) , which is fitted to supporting structure 15, in particular is fixed firmly to walls 17a, 17b, and has a straight central slot 72 extending in direction D. Plane P3 extends through the longitudinal axis of slot 72, which is wide enough to let through the leg of central body 61, 61b supporting wall 64, 64b, so that first and second pushers 60a, 60b are movable with respect to supporting surface 70. More specifically, when the legs engage slot 72, supporting walls 64, 64b are located on the opposite side of supporting surface 70 to chains 30, 34 and are perpendicular to supporting surface 70. Stacking device 10 comprises an unloading station 80 (Figures 1, 2 and 3) for simultaneously depositing a number of stacks 4 on surface 70. More specifically, unloading station 80 comprises a number of unloading units 82 equally spaced in direction D and for each depositing a respective stack 4 onto surface 70. In the embodiment shown, each unloading unit 82 is located over surface 70 and comprises two oscillating arms 84 having first ends 84a hinged to an edge 8Op of unloading station 80, and second ends 84b with C-shaped gripping portions. Arms 84 are movable between a gripping position (Figure 2) in which they are parallel and grip a stack 4, and an unloading position (Figures 1 and 3) in which arms 84 are parted to release stack 4 onto surface 70. Feed system 1 is controlled by an electronic control unit 90, which powers motors 53 and 45 to control the movement of first chain 30 and second chain 34 independently. Motors 45 and 53 are also connected to respective encoders 45e and 53e, which supply control unit 90 with feedback signals El, E2 to indicate instantaneously and continuously the position of chains 30, 34 and pushers 60a, 60b in direction D. Control unit 90 also communicates with sensors 92, 93 (e.g. inductive sensors - shown schematically) for detecting the passage of pushers 60a, 60b respectively through a reference position. Electronic control unit 90 also cooperates with unloading station 80. Operation of feed system 1 under the control of electronic unit 90 is shown in Figure 8, which shows a logic diagram of the operations performed to control the first and second conveying system. To begin with, a first block 100 operates first linear conveying system 12 (i.e. powers motor 53 and operates chain 30) to position first pushers 60a beneath unloading station 80. First conveying system 12 is then arrested (block 110 downstream from block 110) with each supporting wall 64 located between two adjacent unloading units 82. Block 110 is followed by a block 120 which commands unloading station 80 to unload stacks 4 simultaneously : arms 84 are controlled synchronously to move into the unloading position and release stacks 4 onto supporting surface 70. More specifically, each stack 4 comes to rest on surface 70 close to a respective supporting wall 64, with which it does not interfere as it drops down. While the operations in blocks 100, 110 and 120 are being performed, second linear conveying system 13 is so positioned as to prevent second pushers 60b from interfering with first pushers 60a. More specifically, during the above operations, second linear conveying system 13 feeds stacks 4 to the input of packaging machine 7. Block 120 is followed by a block 130, which restarts and linearly increases the speed of first conveying system 12 in controlled manner, so that each wall 64 moves with respect to and is brought gently into contact with the adjacent stack 4 to prevent any damage to stack 4 or objects 5 in stack 4. Stacks 4 are thus pushed by pushers 60a and fed (at preferably constant speed) by first conveying system 12 in straight direction D to output lb and- packaging machine 7 (Figure 1) . More specifically, packaging machine 7 is fed with a stream of stacks 4 of objects 5 traveling at constant speed. After feeding stacks 4 to packaging machine 7, pushers 60a rotate about pulley 32 back to input la. Block 130 is followed by a block 140, which operates second conveying system 13 to position second pushers 60b beneath unloading station 80. More specifically, when the last of the first pushers 60au (i.e. the trailing pusher 60a furthest away from output lb in- direction D) moves away from the last unloading unit 82u at unloading station 80 (i.e. the unloading unit 82 closest to output lb) , the first of the second pushers 60bp (i.e. the leading pusher 60b in the traveling direction • of conveying system 13) can be positioned beneath the last unloading unit 82u (Figures 2 and 3 ) . Block 140 is followed by a block 150, which, at this point, arrests second conveying system 13 with each supporting wall 64b located between two adjacent unloading units 82. Block 150 is followed by a block 160 which commands unloading station 80 to unload stacks 4 simultaneously : arms 84 are controlled synchronously to move into the unloading position and release stacks 4 onto supporting surface 70. While the operations in blocks 140, 150 and 160 are being performed, first linear conveying system 12 is so positioned as to prevent first pushers 60a from interfering with second pushers 60b. More specifically, during the above operations, first conveying system 12 feeds stacks 4 to output lb and packaging machine 7. Second conveying system 13 is then re-started (block 170 downstream from block 160) and increased linearly in speed (as in block 130) , so that walls 64b are brought gently into contact with stacks 4, which are thus fed in direction D. More specifically, the speed of second conveying system 13 is adjusted (in particular, is increased, reduced and then maintained constant - block 180 downstream from block 170) so that the leading pusher 60bp (i.e. the pusher 60b closest to output lb) is positioned adjacent to the trailing pusher 60au (i.e. in this case, the pusher 60a furthest from output lb) with a constant spacing between pushers 60a, 60b, so as to ensure a continuous stream of stacks 4 to output lb and therefore to the input of packaging machine 7. More specifically, the distance, in direction D, between the trailing pusher 60au and the leading pusher 60bp is made equal to the distance between two adjacent pushers 60a, 60b. Packaging machine 7 receives stacks 4 supplied, with no interruptions and with the same spacing Ds between one stack and the next, by first conveying system 12 and second conveying system 13. When the first conveying system completes supply of stacks 4 (block 190 downstream from block 180), supply is continued by system 13, and block 190 goes back to block 100 to supervise the loading of further stacks 4 onto conveying system 12. The operations in blocks 100-190 are then repeated to ensure a continuous supply of stacks to output lb by conveying systems 12 and 13. The advantages of the present invention will be clear from the foregoing description: stacks 4 of objects 5 are fed onto surface 70 with pushers 60a, 60b stationary with respect to supporting surface 70, thus preventing any impact between pushers 60a, 60b and the stacks, and any damage to the stack or objects; employing two independently controlled conveying systems, as described above and shown in Figure 8, provides, despite arresting the first and second conveying system (blocks 110 and 150) , for ensuring a continuous stream of stacks and, hence, continuous constant supply to the input of packaging machine 7. Clearly, changes may be made to the packaging machine feed system as described herein without, however, departing from the scope of the present invention.

Claims: CLAIMS 1) A feed system for feeding a packaging machine, and which receives a number of stacks (4) at an input (la) and feeds said stacks in a traveling direction (D) to an output (lb) communicating with said packaging machine (7) ; each said stack being defined by at least two superimposed flat objects (5) ; and the feed system being characterized by comprising: - a first conveying system (12) having first pushers (60a) for moving said stacks from said input (la) to said output (lb) ; a second conveying system (13) having second pushers (60b) for moving said stacks from said input (la) to said output (lb) ; said first and said second conveying system (12, 13) being powered by respective first and second drive means (53, 45) controlled by an electronic control unit (90) to set said first pushers or said second pushers to a stop position (110, 150) during supply of said stacks to said input; said electronic control unit regulating the movement of said first conveying system and said second conveying system to ensure a continuous stream of stacks of objects to the output of said feed system. 2) A feed system as claimed in Claim 1, characterized in that said input (la) cooperates with an unloading station (80) for feeding said stacks to the first and second conveying system; said electronic control unit comprising: first control means (100) for controlling the movement of the first conveying system (12) to set said first pushers (60a) to an unloading position at said unloading station (80) ; - first stop means (110) for arresting the first conveying system (12) with said first pushers in the unloading position; - first unloading means (120) for emitting a command to unload the stacks (4) ; each stack being positioned close to a respective first pusher (60a) with which it does not interfere during the unloading operations; - first re-starting means (130) for re-starting the first conveying system (12) , the speed of which increases in controlled manner; each first pusher moving with respect to the adjacent stack (4) and being brought gently into contact with said stack (4) ; said first re-starting means (130) ensuring said stacks (4) are fed in said traveling direction (D) to said output (lb) ; - second control means (140) for controlling the movement of the second conveying system (13) to set said second pushers (60b) to said unloading position; - second stop means (150) for arresting the second conveying system (13) with said second pushers in the unloading position; second unloading means (160) for emitting a command to unload the stacks (4) ; each stack being positioned close to a respective second pusher ' (60b) with which it does not interfere during the unloading operations; - second re-starting means (170) for re-starting the second conveying system (13) , the speed of which increases in controlled manner; each second pusher moving with respect to the adjacent stack (4) and being brought gently into contact with said stack (4) ; said second re-starting means (170) ensuring said stacks (4) are fed in said traveling direction (D) at a speed so regulated that a leading pusher (60bp) forming part of the second pushers is positioned adjacent to a trailing pusher (60au) forming part of the first pushers, so as to ensure a continuous stream of stacks (4) to the output (lb) of the feed system. 3) A feed system as claimed in Claim 2, characterized in that said first re-starting means (130) re-start the first conveying system (12) and increase said speed linearly; and said second re-starting means (170) re-start the second conveying system (13) and increase said speed linearly. 4) A feed system as claimed in Claim 2 or 3, characterized in that said second re-starting means (170) adjust the distance (Ds) , in said traveling direction (D) , between said trailing pusher (60au) and said leading pusher (60bp) so that it equals the distance between two adjacent pushers (60a, 60b) . 5) A feed system as claimed in any one of the foregoing Claims, characterized in that said first conveying system (12) is linear and conveys said stacks (4) in a straight traveling direction (D) ; said second conveying system (13) being linear and conveying said stacks (4) in said straight traveling direction (D) . 6) A feed system as claimed in any one of the foregoing Claims, characterized in that said first pushers (60a) and said second pushers (60b) are movable along the same plane (P3) ; said electronic control unit (90) controlling the first conveying system (12) and the second conveying system (13) so that said first pushers and said second pushers are not positioned alongside, and do not come into contact with, one another. 7) A feed system as claimed in any one of the foregoing Claims, characterized in that said first conveying system (12) comprises a powered first chain (30) ; said first pushers being spaced along a portion of said first chain (30) and being carried by links of said first chain (30) ; said second conveying system (13) comprising a powered second chain (34) ; and said second pushers being spaced along a portion of said second chain (34) and being carried by links of said second chain (34) . 8) A feed system as claimed in Claim 7, characterized in that each first pusher (60a) comprises a central body (61) connected to a link of the first chain (30) by a respective pin (62) extending from the central body (61) and crosswise to the traveling direction (D) of the first chain (30) ; each second pusher (60b) comprising a central body (61b) connected to a link of the second chain (34) by a respective pin (62b) extending from the central body (61b) and crosswise to the traveling direction (D) of the second chain (34) . 9) A feed system as claimed in Claim 8, characterized in that each first pusher (60a) comprises a supporting wall (64) carried by a leg extending from said central body (61) ; said supporting wall being perpendicular to the traveling direction (D) ; each second pusher (60b) comprising a supporting wall (64b) carried by a leg extending from said central body (61b) ; and said supporting wall being perpendicular to the traveling direction (D) . 10) A method of feeding stacks of objects to a packaging machine; said stacks moving in a traveling direction (D) extending between a supply input (la) and an output (lb) communicating with said packaging machine; and the method being characterized by comprising the steps of : - feeding said stacks to a first conveying system (12) having first pushers (60a) for moving said stacks from said input ' (la) to said output (lb) ; - feeding said stacks to a second conveying system (13) having second pushers (60b) for moving said stacks from said input (la) to said output (lb) ; - controlling (90, 110, 150) said first and said second conveying system (12, 13) to set said first pushers or said second pushers to a stop position during supply of said stacks to said input; - adjusting (90, 100-190) the movement of said first conveying system and said second conveying system to ensure a continuous stream of stacks to the output of said feed system. 11) A method as claimed in Claim 10, characterized in that said adjusting step comprises the steps of: - commanding (100) movement of the first conveying system (12) to set said first pushers (60a) to an unloading position at an unloading station (80) for feeding said stacks of objects to said input; - arresting (110) the first conveying system (12) with said first pushers in the unloading position; - imparting (120) a command to unload the stacks; each stack being positioned close to a respective first pusher (60a) , with which it does not interfere during the unloading operations; - re-starting (130) the first conveying system (12) and controlling the speed of the first conveying system so that each first pusher moves with respect to the adjacent stack. (4) and is brought gently into contact with said stack (4) ; - feeding said stacks (4) in the traveling direction (D) to said output (lb) ; - commanding (140) movement of the second conveying system (13) to set said second pushers (60b) to said unloading position; - arresting (150) the second conveying system (13) with said second pushers in the unloading position; - imparting (160) a command to unload the stacks (4) ; each stack being positioned close to a respective second pusher (60b) , with which it does not interfere during the unloading operations; - re-starting (170) the second conveying system (13) and controlling the speed of the second conveying system so that each second pusher moves with respect to the adjacent stack (4) and is brought gently into contact with said stack (4) ; - feeding said stacks (4) in the traveling direction, (D) at a speed so regulated that a leading pusher (60bp) forming part of the second pushers and closest to the output (lb) is positioned adjacent to a trailing pusher (60au) forming part of the first pushers and furthest from the output (lb) , so as to ensure a continuous stream of stacks (4) to the output (lb) of the feed system.

Inventors: ALOTTO VALERIO, ALOTTO, VALERIO
Applicants: ALOTTO VALERIO, SYNCHROSYS S R L, ALOTTO, VALERIO, SYNCHROSYS S.R.L.
Application year: 2001
Main classification: B65B35
IPC codes: B65B35, B65G17, B65G47