Patent Application
20050288162
The present invention relates to a method and unit for folding coupons on a packing machine.
The present invention may be used to particular advantage on a cigarette packing machine, to which the following description refers purely by way of example.
It is fairly common practice to combine a packet of cigarettes with a coupon, which is normally enclosed inside the packet with the group of cigarettes. The coupon may be either the same size as or larger than the packet of cigarettes; in which latter case, it is folded for insertion inside the packet.
A known packing machine for producing packets of cigarettes with folded coupons comprises a conveyor for feeding a number of seats, each containing a respective group of cigarettes, along a packing path. The packing path extends through a feed station where a wheel, comprising a number of gripping heads, extracts the folded coupons one at a time from the bottom of a stack housed inside a store, and feeds each folded coupon to a respective seat on a packing conveyor, together with the corresponding group of cigarettes.
Various tests show known packing machines of the type described above to function satisfactorily at relatively low speed (up to 4-5 packets of cigarettes a second) but poorly at high speed (over 7-8 packets of cigarettes a second) on account of the fairly long time required to remove a folded coupon correctly from the bottom of a stack of folded coupons.
Packing machines have therefore been proposed, in which, at the coupon feed station, a flat strip of preprinted coupons is unwound off a reel and cut into individual coupons by a cutting device; each coupon is fed to a folding unit by which it is folded; and a transfer device receives each folded coupon from the folding unit, and feeds the folded coupon to a respective seat on a packing conveyor, together with the corresponding group of cigarettes.
One example of a cigarette packing machine with an on-line coupon-folding feature is described in Patent Application WO-2004003726-A1. More specifically, the packing machine comprises a roller folding unit or so-called “buckle folder” in turn comprising a succession of folding stations, each for making one fold in the coupons, and each having two counter-rotating rollers and a locating member. In actual use, a coupon is received from a folding station so as to rest on the two counter-rotating rollers, with one end of the coupon resting against the locating member. At this point, an intermediate portion of the coupon is gradually engaged by the counter-rotating rollers, so that the coupon is fed between the counter-rotating rollers and so folded.
Another example of a “buckle folder” roller folding unit is described in Patent Application EP-0522408-A1.
“Buckle folder” roller folding units have numerous advantages: they are compact, cheap and easy to produce, and can operate at high speed. On the other hand, good-quality folding tends to be restricted to a small range of operating speeds. That is, a “buckle folder” roller folding unit only operates well at substantially constant operating speed; which limitation poses serious problems on a cigarette packing machine, which is subject to numerous changes in speed to adapt to the operating conditions of the automatic (cigarette manufacturing, cellophaning, and cartoning) machines to which it is connected, as well as for cleaning, adjustment, maintenance and format changes.
It is an object of the present invention to provide a method and unit for folding coupons on a packing machine, designed to eliminate the aforementioned drawbacks, and which, in particular, are cheap and easy to implement.
According to the present invention, there are provided a method and unit for folding coupons 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 accompanying drawings, in which:
Number 1 in
As shown in
Each folding station 4 comprises two counter-rotating folding rollers 6; and two locating members 7 located side by side at one end of a feed path of coupons 2 extending over the two folding rollers 6. The folding station 4 at the input of folding unit 1 is fitted with a lead-in roller 8 which cooperates with a respective folding roller 6; and a lead-in member 9 is provided at each pair of locating members 7, has a funnel-shaped inlet, and provides for feeding coupons 2 correctly to locating members 7.
As shown in
In actual use, a flat coupon 2 is fed by a known conveyor (not shown) to the input of folding unit 1, so that it is engaged between lead-in roller 8 and the corresponding folding roller 6; and the drawing action of lead-in roller 8 and corresponding folding roller 6 feeds the flat coupon 2 over the two folding rollers 6 at the first folding station 4 until one end of coupon 2 comes to rest against locating members 7 at the first folding station 4. At this point, an intermediate portion of coupon 2 is gradually engaged by folding rollers 6 at the first folding station 4, so that coupon 2 is fed between the folding rollers 6, is folded about a fold line 3, and is then fed over the two folding rollers at the second folding station 4. The folding process is repeated, as described above, at the second and third folding station 4 to complete the folding of coupon 2.
The position of each fold line 3 along coupon 2 is therefore determined by the position of the corresponding locating members 7 with respect to the corresponding pair of folding rollers 6, i.e. by the position of corresponding locating members 7 along the feed path of coupons 2.
Folding unit 1 also comprises an adjusting device 11 by which to adjust the position of each pair of locating members 7 along the feed path of coupons 2 during normal operation of folding unit 1. As shown in
As shown in
Adjusting device 11 therefore provides for adjusting the position of each pair of locating members 7 independently of the positions of the other pairs of locating members 7. In an alternative embodiment not shown, adjusting device 11 comprises a single linear electric motor 13, and so provides for adjusting the positions of all the pairs of locating members 7 together.
Adjusting device 11 is connected to a sensor device 16 for cyclically determining the operating speed of folding unit 1 (i.e. the operating speed of folding stations 4), and so provides for adjusting the position of each pair of locating members 7 along the feed path of coupons 2 as a function of the operating speed of folding unit 1. In a preferred embodiment, adjusting device 11 comprises a memory 17 storing an adjustment table, which, for each operating speed value of folding unit 1, supplies adjusting device 11 with a corresponding position value of each pair of locating members 7.
In a further embodiment, adjusting device 11 comprises a detecting device 18 located downstream from folding stations 4 and for determining the position of at least one fold line 3 of each coupon 2, so that adjusting device 11 adjusts the position of each pair of locating members 7 along the feed path of coupons 2 as a function of the position of at least one fold line 3. Detecting device 18 is preferably optical, and determines the position of fold lines 3 indirectly by analyzing folded coupon 2. More specifically, detecting device 18 determines the position of fold lines 3 as a function of the size of folded coupon 2 and/or the degree of overlap of the free portions of folded coupon 2.
In various alternative embodiments, adjusting device 11 adjusts the position of each pair of locating members 7 as a function of the operating speed of folding unit 1, or as a function of the position of fold lines 3, or as a function of both the operating speed of folding unit 1 and the position of fold lines 3.
Preferably, upstream from folding unit 1, an unwinding device (not shown) is provided to unwind a flat strip (not shown) off a reel (not shown), and a cutting station (not shown) is provided to cut the flat strip, along a cutting line crosswise to the travelling direction of the strip, into successive coupons 2, which are then fed to folding unit 1. Downstream from folding unit 1, at least one gripping head (not shown) is provided to feed each folded coupon 2 into a seat on a packing conveyor (not shown) and onto packing material (not shown) inside the seat. A first motor (not shown) is provided to unwind the flat strip continuously at substantially constant speed off the reel, and a second motor (not shown) is provided to feed the strip in steps to the cutting station. A compensating device (not shown) is interposed between the first and second motor to form a loop of varying length in the strip upstream from the cutting station, so that the speed of the strip is zeroed cyclically at the cutting station to enable the strip to be fed to the cutting station in steps.
Folding unit 1 as described above has numerous advantages: it is compact, is cheap and easy to produce, can operate at high speed, and provides for good-quality folds within a wide range of operating speeds (practically from zero to nominal speed). In other words, folding unit 1 as described operates well at all possible operating speeds, which can therefore be safely changed continually.
In view of its numerous advantages, folding unit 1 as described may also be used to advantage on other automatic machines for packing products other than cigarettes, or on automatic machines for other than product packing purposes.
| Number | Date | Country | Kind |
|---|---|---|---|
| BO2004A000405 | Jun 2004 | IT | national |
