The present invention relates to a packing unit and method for folding a blank on a packing machine.
The present invention may he used to advantage to fold a blank on a so-called ‘boxing’ machine, i.e. a packing machine for packing loose packages in a cardboard box, to which the following description refers purely by way of example.
Known boxing machines comprise an initial grouping unit where a number of lines of successive adjacent individual packages are formed; and a final grouping unit where a number of lines of packages are superimposed to form groups of packages. Downstream from the final grouping unit, a packing unit packs each group of packages into a respective cardboard box.
The packing unit comprises a blank store containing a stack of flat blanks; a packing belt conveyor with a succession of pockets; and a feed device which withdraws the first blank in the stack by suction and inserts it into a pocket on the packing conveyor; as it is inserted into the pocket on. the packing conveyor, the blank is folded onto a ‘U’. Next, a group of packages is inserted longitudinally into a packing conveyor pocket containing a U-folded blank, and the blank is gummed (i.e. glued) and folded further about the group of packages to form a cardboard box.
A unit of the above type described in document JP2004299708 comprises a packing conveyor with two pairs of side by side conveyor belts. So the blank is conveyed along the packing path inside pockets defined by the gaps between spacers on the conveyor belts. More specifically, the pockets are adjustable to adapt the seats to the content being conveyed.
Known packing units of the above type work well, but have the major drawback of not being very flexible. The flexibility of the conveying part does not match up with that of the packing unit as a whole, especially as regards feeding the blanks and unloading the finished containers. That is, chancing the blank format (i.e. size) involves changing several component parts on the packing unit. This is a particularly painstaking, time-consuming job requiring skilled labour, in that, in addition to removing parts and assembling new ones, the packing unit as a whole must be set up to make sure the new parts interact properly with the rest of the unit. This lack of flexibility is an increasingly important issue in view of the general market tendency towards small production lots with frequent changeovers.
It is an object of the present invention to provide a packing unit and method for folding a blank on a packing machine, designed to eliminate the above drawbacks (i.e. which are highly flexible) and which at the same time are cheap and easy to implement.
According to the present invention, there are provided a packing unit and method for folding a blank on a packing machine, as claimed, in the accompanying claims.
A non-limiting embodiment of the present invention will be described by way of example with reference to the attached drawings, in which:
Number 1 in
Packing machine 1 comprises an input conveyor 5 (shown schematically in
As shown in
As shown in
As shown in
Packing conveyor 17 comprises at least a first conveyor belt 23; and at least a second conveyor belt 24 separate from, parallel to, and alongside first conveyor belt 23. First and second conveyor belts 23 and 24 define a bottom wall of pocket 18.
More specifically, as shown in
The distance between retaining member 25 and retaining member 26 in the direction of packing path P defines the length L of pocket 18, as shown by way of example in
Said length L is therefore adjustable according to the format of blank 4. And, by adjusting the length of pocket 18 on the conveyor, blanks 4 of different formats (i.e. different sizes) can be retained inside the same pocket without changing any component parts on packing unit 10.
Pockets 18 on packing conveyor 17 are arranged successively and spaced apart (i.e. a given distance is left between each pocket 18 and the two adjacent pockets 18) by a spacing distance S defined by the distance between retaining member 26 of one pocket 18 and retaining member 25 of the upstream pocket 18 in the direction of packing path P (as shown in
Spacing distance S therefore allows the two suction pickup heads 21, 22 to operate as described in detail below.
To adjust length L, packing conveyor 17 produces a relative movement between conveyor belt 23 and conveyor belt 24, to move retaining members 25, 26 of pocket 18 towards or away from each other according to the format (size) of blank 4.
Each conveyor belt 23 is looped about two end pulleys 27 and 28; each end pulley 27 is mounted idly (i.e. rotates freely about a central axis of rotation) while each end pulley 28 is powered, i.e. is connected mechanically to a common electric motor 29 which rotates both powered end pulleys 28 synchronously. Likewise, each conveyor belt 24 is looped about two end pulleys 30 and 31; each end pulley 30 is mounted idly (i.e. rotates freely about a central axis of rotation); while each end pulley 31 is powered, i.e. is connected mechanically to a common electric motor 32 which rotates both powered end pulleys 31 synchronously, and is separate from and independent of electric motor 29.
In actual use, end pulleys 27 and 28 of conveyor belts 23 can be operated out of phase with respect to end pulleys 30 and 31 of conveyor belts 24 to adjust the length of pockets 18 according to the format (i.e. size) of blank 4, by producing a relative movement between belt 23 and belt 24, as described previously. In other words, the timing of end pulleys 27, 28 of conveyor belts 23 and end pulleys 30, 31 of conveyor belts 24 can be adjusted to produce a relative movement between the two conveyor belts 23 and the two conveyor belts 24, and so move retaining members 25 and 26 of each pocket 18 towards or away from each other to adjust the length of pockets 18 according to the format (i.e. size) of blank 4. In actual fact, only the timing of powered end pulleys 28 and 31 (whose angular position is controlled actively by electric motors 29 and 32) is actively adjusted, and the timing of idle end pulleys 27 and 30 adapts passively to that of powered end pulleys 28 and 31. Obviously, the timing of powered end pulleys 28 and 31 is only actively adjusted when packing machine 1 is off and empty, i.e. during a. format changeover to adapt packing machine 1 to cardboard boxes 3 (and therefore blanks 4) a different format (i.e. size). More specifically, when working with wider or narrower panels 12 of blanks 4, the length of each pocket 18 is adjusted to always equal the width of panels 12 of blanks 4 (obviously, allowing for the necessary tolerances).
In the
Feed device 19 comprises a suction pickup head 21 which engages panel 11 of blank 4 inside store 20; and a suction pickup head 22 which engages panel 13 of blank 4 in store 20. Feed device 19 also comprises actuating devices 33, 34 for moving pickup heads 21, 22 from a withdrawal position at store 20, to a release position at packing conveyor 17, to insert blank 4 into pocket 18 on packing conveyor 17, and to release blank 4, folded into a ‘U’, inside pocket 18.
Actuating devices 33, 34 alter the distance between pickup heads 21, 22 and the packing unit at store 20 according to the format (i.e. size) of blank 4. So, in addition to flexible pockets 18, pickup heads 21, 22 are also designed for maximum flexibility, to work with blanks of different sizes.
As the pickup heads move from the withdrawal to the release position, actuating devices 33, 34 produce a relative movement between pickup head 21 and pickup head 22 to fold blank 4 into a ‘U’ before it is inserted into pocket 18 on packing conveyor 17. More specifically, as the pickup heads move from the withdrawal position to the release position, operation of actuating devices 33, 34 is adjustable to adjust the movements of pickup heads 21, 22 according to the format of blank 4.
This also allows for flexiblity in folding the blank into a ‘U’, by allowing the same blank or different blanks to be folded into a ‘U’ at different portions.
As shown in
Actuating device 33 comprises a supporting plate 35 hinged (i.e. fitted in rotary manner) to a fixed frame (not shown) of packing machine 1, and which is rotated with respect to the fixed frame about a horizontal axis of rotation 36 by an electric motor 37 offset with respect to axis of rotation 36. More specifically, the shaft of electric motor 37 is connected mechanically to supporting plate 35 by a mechanism comprising two mutually hinged arms. Supporting plate 35 is fitted with an arm hinged (i.e. fitted in rotary manner) to supporting plate 35, and which is rotated with respect to supporting plate 35 about a horizontal axis of rotation 39 (parallel to axis of rotation 36) by an electric motor 40 (also fitted to supporting plate 35 and offset with respect to axis of rotation 39). Arm 38 is hinged at one end to supporting plate 35, and at the opposite end is connected rigidly to pickup head 21. In other words, pickup head 21 is connected rigidly to one end of arm 38. So actuating device 33 can rotate pickup head 21 about both axes of rotation 36 and 39, which are spaced apart and parallel.
Actuating device 34 comprises an arm 41 hinged (i.e. fitted in rotary manner) to the fixed frame (not shown) of packing machine 1, and which is rotated with respect to the fixed frame about a horizontal axis of rotation 42 by an electric motor 43 coaxial with axis of rotation 42. Arm 41 is fitted with an arm 44 hinged (i.e. fitted in rotary manner) to arm 41, and which is rotated with respect to arm 41 about a horizontal axis of rotation 45 (parallel to axis of rotation 42) by an electric motor 46 (also fitted to arm 41 and offset with respect to axis of rotation 45). More specifically, the shaft of electric motor 46 is connected mechanically to arm 44 by a mechanism comprising two mutually hinged arms. Arm 44 is hinged at one end to arm 41, and at the opposite end is connected rigidly to pickup head 22. In other words, pickup head 22 is connected rigidly to one end of arm 44. So actuating device 34 can rotate pickup head 22 about both axes of rotation 42 and 45, which are spaced apart and parallel.
Normally, when making a format, change, i.e. changing over to blanks 4 of different sizes, the movements of the two pickup heads 21 and 22 (i.e. the laws of motion of electric motors 37, 40, 43 and 46) need simply be software adjusted (i.e. with no physical work involved). Obviously, the movements of the two pickup heads 21 and 22 are only adjusted when packing machine 1 is off and empty, i.e. during a format changeover to adapt packing machine 1 to cardboard boxes 3 (and therefore blanks 4) of a different format (i.e. size). In one possible embodiment, actuating device 33 and/or actuating device 34 may be fitted to the frame of packing machine 1 to move vertically to adjust the vertical position of pickup head 21 and/or pickup head 22 according to the format (i.e. size) of blank 4. In one possible embodiment, actuating devices 33 and 34 are translated vertically by hand (by pushing manually on the supports of actuating devices 33 and 34, or by rotating a handwheel); in a preferred embodiment, vertical translation of actuating devices 33 and 34 is controlled by electric actuators feedback-controlled by position sensors.
As shown in
Operation of packing unit 10 to feed a blank 4 into a pocket 18 on packing conveyor 17 will now be described with reference to
To begin with, as shown in
Next, as shown in
Finally, as shown in
As shown in
In a preferred embodiment, pickup heads 21 and 22 rotate panels 11 and 13 of blank 4 over 90° with respect to panel 12 before inserting the U-folded blank 4 inside pocket 18 on packing conveyor 17; next, pickup heads 21 and 22 rotate panels 11 and 13 of blank 4 the opposite way with respect to panel 12, so that panels 11 and 13 are perpendicular to panel 12 when the U-folded blank 4 is inside pocket 18 on packing conveyor 17. In other words, before inserting the U-folded blank 4 into pocket 18 on packing conveyor 17, pickup heads 21 and 22 ‘close’ the formed by panels 11 and 13, by rotating them over 90° (e.g. 100-110°), so the U-folded blank 4 is easier to insert inside pocket 18; and, once the U-folded blank 4 is inserted inside pocket 18, pickup heads 21 and 22 ‘open’ the ‘U’ formed by panels 11 and 13, so panels 11 and 13 are perfectly perpendicular (i.e. exactly 90°) to panel 12.
In a preferred embodiment, as the U-folded blank 4 is inserted inside pocket 18 on packing conveyor 17, the two movable folding devices 47 are set to the release position (shown, for example, in
Movable folding devices 47 and fixed folding devices 50 serve to fold down, and keep folded down, wings 16 of panel 12 of blank 4, so that, at feed station S2, wings 16 of panel 12 in no way impede insertion of group 9 of packages 2 into blank 4 inside pocket 18 on packing conveyor 17.
Packing unit 10 described has numerous advantages.
Firstly, packing unit 10 described is highly flexible, i.e. provides for rapidly changing the format (i.e. size) of blanks 4.
The format (i.e. size) of blanks 4 can be changed by simply appropriately altering the movements of pickup heads 21 and 22, which can be done by software adjusting (i.e. with no physical work involved) the laws of motion of electric motors 37, 40, 43, 46, without changing any actual component parts of packing unit 10. Moreover, the format (i.e. size) of blanks 4 can be changed by simply adjusting the length of pockets 18 on packing conveyor 17, by software adjusting (i.e. with no physical work involved) the law of motion of at least one of electric motors 29 and 32, without changing any actual component parts of packing unit 10. In other words, all the operations involved in changing the format (i.e. size) of blanks 4 are performed without changing any actual component parts of packing unit 10, and with no manual labour on the part of the operator.
Secondly, packing unit 10 described is also cheap and easy to produce.
Finally, packing unit 10 described enables extremely high output rates to be achieved, by treating blanks 4 ‘gently’, i.e. not subjecting them to severe mechanical stress (i.e. sharp acceleration/deceleration).
Number | Date | Country | Kind |
---|---|---|---|
BO2013A000387 | Jul 2013 | IT | national |