This invention relates generally to a method and apparatus for delivering an article to a receiver, for example for loading a series of partially-formed paperboard cartons in open-ended, rectilinear tube configurations, onto respective arms or mandrels of a rotating turret upon which one end of each carton is then sequentially folded, closed, and sealed as the turret indexes the cartons through various circumferentially-spaced stations in a machine for forming cartons from carton blanks.
Carton forming machines having turrets for indexing partially-formed, open-ended cartons through end folding, closing, and sealing stations are well-known in the art. For example, a carton folding, filling, and sealing machine known as the ELOPAK® P-S50 includes such a turret. The ELOPAK® P-S50 also includes a carton blank magazine that holds a plurality of paperboard carton blanks in flattened form and a feeder that includes suction cups to engage the carton blanks in the magazine and pull them open into open-ended rectilinear tube form. The turret has a plurality of radially-extending arms or mandrels. Each mandrel is shaped to axially receive a partially-formed, open-ended, paperboard carton. The turret is rotatably supported and configured to rotate the mandrels through a plurality of circumferentially-spaced work stations where successive operations are performed to close and seal the bottom ends of cartons supported on the mandrels.
A turret loading device of the ELOPAK® P-S50 includes a loader guide that receives cartons in open-ended rectilinear tube form from the feeder and deposits them over the turret mandrels for transport through the bottom-forming work stations. The turret loading device includes an endless conveyor chain supported on chain guides between an upstream sprocket and a downstream sprocket. A loader motor drives the chain continuously in one sense at a constant velocity by turning the downstream sprocket. The turret loading device of the P-S50 also includes plastics loading fingers that are supported at spaced locations along the chain and extend radially outward from along the chain path in positions where they engage trailing edges of the open-ended cartons to propel the cartons along loader guide rails and onto the respective turret mandrels.
The P-S50 machine requires a highly accurate positional relationship to exist between the loading finger and the trailing edge of the carton, because the finger has to slide accurately past that trailing edge; if the finger leaves contact with that edge too late, there is a risk of damage to that edge, but if the finger leaves contact with that edge too early, the carton is not fully loaded onto the mandrel or rebounds. If this relationship is slightly inaccurate, time-consuming mechanical adjustment, or even reworking of parts, sometimes by trial and error, may be necessary.
As each carton reaches a mounted position on one of the mandrels, the finger pushing that carton continues downward in an arc as the chain carries that finger around the downstream sprocket. Since this downward arcing motion of each finger around the downstream sprocket could damage the trailing edges of the cartons as the chain carries the fingers forward and downward, the fingers are carefully shaped to endeavour to preclude such damage.
According to one aspect of the present invention, there is provided apparatus comprising a loading device including a loader for forwarding an article, a receiving device including a receiver for receiving said article delivered thereto by said loader, an advancing device arranged to advance said loader on an endless path a driving device drivingly connected to said receiving device for advancing said receiver along a second path extending into the region of a portion of said endless path at which said loader delivers said article to said receiver, said advancing device being arranged to reverse said loader momentarily out of said region immediately following delivery of said article to said receiver.
According to another aspect of the present invention, there is provided a method comprising advancing a loader along an endless path into a region of which a second path extends and causing said loader to deliver an article to a receiver located on said second path at said region, momentarily reversing said loader out of said region immediately following the delivery of said article to said receiver, and advancing said receiver along said second path.
Owing to the present invention it is possible to avoid interference between the loader and an article on the receiver (or the receiver itself) and thereby to avoid consequential damage.
In particular, a highly accurate positional relationship between the carton and the loader may not be so necessary, whilst by using a brushless servo motor with pulse train command and encoded feedback it is nevertheless possible to attain a highly accurate positional relationship between the carton and the loader.
Thus, according to a third aspect of the present invention, there is provided apparatus comprising a loading device including a loader for forwarding an article, a receiving device including a receiver for receiving said article delivered thereto by said loader, an advancing device arranged to advance said loader on an endless path a driving device drivingly connected to said receiving device for advancing said receiver along a second path extending into the region of a portion of said endless path at which said loader delivers said article to said receiver, and a controller connected to said advancing device and said driving device for controlling said advancing device and said driving device said advancing device being a brushless servo motor with pulse train command by said controller and with encoded feedback to said controller as to the position of said brushless servo motor.
In a preferred embodiment of the invention, a carton forming machine turret loading apparatus is provided for loading the articles, which are partially-formed open-ended cartons, onto respective receivers, which are mandrels of a rotatable turret that indexes each carton through circumferentially-spaced work stations. The loading device is a conveyor arranged to propel a series of longitudinally-oriented cartons, in open-ended rectilinear tube form, along a load path and to load the cartons onto respective turret mandrels when those mandrels are axially-aligned with the load path. The turret loading apparatus also includes a loader guide arranged to guide cartons in open-ended rectilinear tube form axially along the load path and to maintain the cartons in axial alignment with respective turret mandrels. The advancing device is a loading servo motor drivingly connected to the conveyor and there are loaders, in the form of loading pushers carried by the conveyor, to engage successive cartons and propel them along the loader guide and onto respective mandrels. The apparatus includes a controller arranged to command the loading servo motor to advance the conveyor and transport each carton along the load path and into a fully mounted position on a mandrel and then to reverse the conveyor momentarily before the turret indexes. This momentary reversal is to prevent the loading pusher from interfering with the subsequent indexing of a carton by the turret or damaging a carton. The reversal also allows for a simpler design of loading pusher, because the pusher need not be designed to slip past the edge of the carton without damaging the carton as it would if mounted on a continuous, i.e. non-reversing, conveyor. Also, because the apparatus is capable of fully withdrawing the pusher, the apparatus can use the pusher to position each carton positively and accurately on its intended mandrel pusher.
The method of the preferred embodiment is of loading partially-formed open-ended cartons onto respective mandrels of an indexing turret of a turret loading apparatus provided adjacent a rotatably supported carton forming machine turret, where the turret loading apparatus includes a loader guide and a conveyor. A first carton is provided in open-ended rectilinear tube form on the loader guide. The conveyor is then advanced until a first loading pusher carried by the conveyor has engaged and propelled the first carton along a load path and onto a first turret mandrel. The first loading pusher is then withdrawn by reversing the conveyor. The turret is then indexed until the turret presents a second turret mandrel in alignment with the conveyor.
In order that the invention may be clearly and completely disclosed, reference will now be made, by way of example, to the accompanying drawings, in which:
Referring to the drawings, a carton form-fill-seal machine turret loading apparatus is indicated at 10 in FIGS. 1 to 10 and is shown in
The apparatus 10 includes a loading conveyor, generally indicated at 18, that propels longitudinally-oriented cartons 12 in open-ended rectilinear tube form serially along a load path 20 and loads the cartons 12 onto respective turret mandrels 14 after each of the mandrels 14 has been rotationally indexed into a position axially aligned with the load path 20. The apparatus 10 also includes a loader guide, generally indicated at 22 in FIGS. 1 to 8, that guides the partially formed cartons 12 axially along the load path 20 and maintains the cartons 12 in axial alignment with respective turret mandrels 14. Five loading pushers 24 in the form of plastics chain lugs 24 are carried by the conveyor 18 at spaced positions along the conveyor to engage successive cartons 12 and propel them along the load path 20 and onto respective turret mandrels 14. A loading motor 28, in the present example a Mitsubishi HC-SF52 servo motor, is drivingly connected to the conveyor 18 as is best shown in
Referring to
The use, to advance the conveyor 18, of a brushless servo motor 28 with pulse train command and with encoded position feedback allows the conveyor more accurately to position the cartons 12 on the mandrels 14. This is because such a servo motor can move almost any practically desired number of pulses, in either direction, over almost any practically desired distance, or for almost any practically desired period of time, at almost any practically desired velocity, and with almost any practically desired degree of acceleration that the PLC 30 directs. A Mitsubishi HC-SF52 servo motor, for example, has 131,072 pulses or positions for each 360 degrees of rotation.
The conveyor 18 includes a chain loop 36 which is carried on an upstream sprocket 40 and the downstream sprocket 32 and an upper run of which is supported on chain guides 38 between those sprockets. The motor 28 is drivingly connected to the upstream sprocket 40. The plastics loading pushers 24 are carried at spaced locations along, and extend radially outward from, the conveyor chain 36 in respective positions to engage and propel successive, partially-formed, open-ended cartons 12 along the loader guide 22 and onto respective turret mandrels 14. Each pusher 24 comprises ultra-high molecular weight (UHMW) polyethylene.
As best shown in
The corner guides 42, 44 receive cartons 12 in open-ended rectilinear tube form from a feeding device shown at 52 in
In practice, the turret loading apparatus 10 is installed in the machine 11 adjacent a carton forming machine turret 16. A first carton 12 is provided in open-ended rectilinear tube form on the loader guide 22 of the apparatus 10 as shown in
The PLC 30 includes a virtual motor or virtual time axis—a software clock that runs continuously in time. The virtual time axis is the virtual master timer for synchronizing all operations of the machine 11 including the feeding device 52, the loading device 18-24, and the turret 16. It has a constant cycle speed that is scaled to 360 degrees of rotation.
The loading servo motor 28, the feeding servo motor 53, and seven further servos or servo axes 64-70 of the machine 11 are slaved to the virtual time axis of the PLC 30 via respective electronic cams programmed into the PLC 30. The seven other servos, shown at 64-70 in
The PLC 30 includes an electronic cam for each of the two servo motors 28 and 53 in the turret loading apparatus 10 as well as for each of the seven further servos 64 to 70 in the machine 11. One of the electronic cams for the turret loading apparatus 10 is a feeder cam, which includes an electronic profile, shown at 75 in
The feeding, loading, and turret cams are programmed so that the loading servo motor 28 is in dwell while the feeding device 52 is feeding, and so that the loading pusher 24 starts retracting before the turret 16 starts indexing. More specifically, once the feeding device 52 has finished moving a carton 12 from the magazine 51 to the load path 20 and opening the carton 12 into its open-ended rectilinear tube form, the PLC 30 commands the loading servo motor 28 to drive the loader chain 36 forwards in a “pre-load index” that moves the carton 12 to a pre-load position set by the loading cam.
In the pre-load position an optical pre-load detection sensor 71 confirms and reports the presence of a carton 12 to the PLC 30. If the sensor 66 detects a carton 12, the PLC 30 commands the loading servo motor 28 to reverse the loader chain 36 about 3 to 5 mm. and to dwell in that position while the PLC 30 commands the feeding servo motor 53 to cause the feeding device 52 to deposit a second partially-formed carton 12 on the load path behind the carton 12 in the pre-load position, while the turret servo motor 64 indexes (together with any immediately preceding carton thereon).
The PLC 30 then commands the loading servo motor 28 to drive the loader chain 36 forwards in a “load index” that moves the first carton 12 from the pre-load position to a loaded position on a turret mandrel 14 while moving the second carton 12 to the pre-load position. At this point the PLC 30, according to the loader cam, commands the loading servo motor 28 to reverse the loader chain 36 about 3 to 5 mm., so that the loading pusher 24 that pushed the first carton 12 into the loaded position is withdrawn from the path of the turret mandrels 14. The PLC 30 then, according to the turret cam, commands the turret servo motor 64 to index the turret 16. This, the normal operating mode of the machine 11, is called the “virtual mode” of operation.
The PLC 30 is also programmed to include, as a safety feature, an electronic clutch for each servo axis. The PLC 30 receives inputs from multiple sensors indicating product in tanks, temperature of heaters, fault status of various machine components, air pressure, vacuum, power, etc. The PLC 30 will allow the clutches to remain “engaged”, allowing the servos to operate, only if all of the sensor indications are positive, indicating that the machine 11 is ready to operate.
In addition, there are certain sensors that serve only to reset or disengage certain electronic clutches. For example, a pre-load detection sensor 71 in the form of a photo eye causes the loader clutch to reset if the pre-load sensor 71 fails to detect a carton 12 in the pre-load position when, according to the loader cam, a carton 12 should be in that position. Similarly, there is a similar post-feeding sensor 67 corresponding to a post-feeding position of a carton 12 on the conveyor 18 and a mounting sensor 69 corresponding to a mounting position of a carton 12 on the mandrel 14.
As an additional safety feature, should any of several safety circuits of the machine 11 be broken owing, for example, to a door being opened or an emergency stop switch pressed, the PLC 30 automatically takes the machine 11 from virtual mode to real mode by removing power from all of the servos, retracting all valves, disabling all of the electronic clutches, and stopping the virtual time axis. Going from virtual mode to real mode removes any possibility of the virtual time axis operating and causing a potentially unsafe situation or damaging equipment.
The PLC 30 in also programmed to include a homing mode that prepares the machine 11 to resume operation after the safety circuits are restored by, e.g., closing any open access doors and/or pressing a reset button. The machine 11 must be homed to align all components properly before returning to the virtual mode.
The machine 11 enters the homing mode either automatically once an operator restores the safety circuits while a key switch is in a run mode, or, if the key switch is in a maintenance mode, an operator must also go to a touch-screen of a human-machine interface (HMI) shown at 73 in
The homing routine includes running the carton loading apparatus 10 in the forward direction and stopping when an optical homing detection sensor 72 sees a loading pusher 24 in a desired homing position. The PLC 30 then zeros out its homing position register and commands an offset from this position for each of the other eight servos of the machine 11. Each offset position is adjustable by manipulating a register in the PLC 30 through the HMI 73. Each offset generally remains the same but may change if, for example, the sensor position changes. The loading servo motor 28 has an encoder 74 that includes a battery back-up 76 to allow it to recall its position even following a power down or in other situations when power from a main power source 78 is unavailable.
Once every servo axis, turret servo motor 64, loading servo motor 28, etc. has completed homing, the PLC 30 returns automatically to virtual mode, ready to “spin.” A start button must then be pressed for three seconds before the virtual clock will start spinning again. The PLC 30 then checks all machine conditions as described above. Once the PLC 30 has provided an indication on the HMI 73 that the machine 11 is homed and ready, an operator must press a feeder start button to engage the electronic clutches in a predetermined sequence. The nine servo axes of the machine 11 then begin to operate in concert, following their respective electronic cam profiles, synchronized to the master virtual axis.
The turret loading apparatus described with reference to the drawings allows for a simpler loading pusher design and can more positively and accurately position cartons on turret mandrels.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/GB05/04822 | 12/14/2005 | WO | 10/5/2007 |
Number | Date | Country | |
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60635910 | Dec 2004 | US |