More specifically, the present invention relates to a method of feeding reels to a machine defined by a cigarette packaging machine, to which the following description refers purely by way of example.

BACKGROUND ART Cigarette packaging machines now operate at such high output rates as to require large amounts of packaging material, which is partly supplied in the form of strips wound into reels. Each reel comprises a strip of packaging material wound about a spool having a central hole, and is fitted onto an unwinding pin on the packaging machine. The strip of packaging material is unwound off the reel, and sheets of packaging material are cut off the strip and folded about groups of cigarettes.

The increase in the amount of packaging material required calls for automatic reel handling to speed up

reel feed to the machine, which in turn calls for determining the position of the reel to enable a reel manipulator to grip the reel by means of a gripping member and align the reel with an unwinding pin on the packaging machine.

Patent EP-A-551,854 relates to a manipulator featuring a reel gripping member and for picking reels off a pallet on which the reels are arranged with their respective axes positioned vertically. The gripping member has a TV camera for picking up an image of a reel; and an arithmetic unit for processing the image data by means of an algorithm based on translation and inversion of the image to determine the coordinates of a characteristic point on the reel. Once the coordinates of the characteristic point on the reel are determined, the manipulator sets the gripping member to a given position to grip the reel correctly.

Though reliable and capable of transferring a large number of reels per unit of time, the arithmetic unit of the above manipulator for processing the points in the image is relatively expensive.

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a straightforward, low-cost method of feeding reels to a machine.

According to the present invention, there is provided a method of feeding reels to a machine from a store of reels close to said machine; each reel having an

axis, a central hole which is engaged by an unwinding pin on said machine, and two flat faces perpendicular to said axis; and the method being characterized by determining whether at least one reference point of a gripping member of a manipulator lies inside the hole of a reel in the store; picking up said reel by means of the gripping member when the reference point lies inside the hole of said reel; and transferring said reel from said gripping member to said unwinding pin.

The present invention also relates to a device for feeding reels to a machine.

According to the present invention, there is provided a device for feeding reels to a machine from a store of reels close to said machine; each reel having an axis, a central hole which is engaged by an unwinding pin on said machine, and two flat faces perpendicular to the axis; and the device being characterized by comprising a manipulator having a gripping member for picking up a reel from said store when at least one reference point of the gripping member lies inside the hole of said reel.

BRIEF DESCRIPTION OF THE DRAWINGS A number of non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a view in perspective, with parts removed for clarity, of a packaging machine featuring a reel feed device in accordance with the present invention;

Figure 2 shows a larger-scale underside view of a gripping member of the Figure 1 device; Figures 3 and 4 show schematic side views of a variation of the gripping member in two operating positions with respect to a reel; Figures 5,6 and 7 are schematic plan views showing the position of a gripping member of the Figure 1 device with respect to a reel.

BEST MODE FOR CARRYING OUT THE INVENTION Number 1 in Figure 1 indicates as a whole a cigarette packaging machine for producing packets of cigarettes not shown.

Machine 1 comprises a feed device 2 for supplying reels 3; and two unwinding pins 4a and 4b for unwinding reels 3. Pin 4a is shown in a position supporting a reel 3 being unwound; and pin 4b in a position to receive a reel 3 from feed device 2.

Each reel 3 has an axis 5, and comprises a spool 6 having a hole 7; and a strip 8 of packaging material wound about spool 6 to form two parallel, substantially flat lateral faces 9 perpendicular to axis 5, and a substantially cylindrical face 10 parallel to axis 5.

Machine 1 comprises a frame 11 supporting unwinding pins 4a and 4b, each of which has an axis 12 and a drive member 13 for switching pin 4a, 4b between the unwinding position in which axis 12 is horizontal, and the receiving position in which axis 12 is vertical.

Device 2 for feeding reels 3 comprises a manipulator

14 for manipulating reels 3, and a platform 15 for supporting a pallet 16 on which reels 3 are arranged in orderly manner with respective axes 5 positioned vertically. Manipulator 14 comprises an articulated arm 17 fixed at one end to frame 11 to rotate about a vertical axis 18, and supporting at the opposite end a gripping member 19 for gripping one reel 3 at a time.

Platform 15 is set to a given position with respect to machine 1, and comprises a lifting device 20, and locating elements 21 for locating pallet 16 with respect to platform 15.

Gripping member 19 is bell-shaped with an axis A, and, as shown more clearly in Figure 2, comprises an annular plate 22 in which are formed suction holes 23 selectively connectable to a vacuum source not shown, and a cavity 24 housing three distance sensors 25. Gripping member 19 has a contact sensor 26 located along annular plate 22 and for arresting manipulator 14 when gripping member 19 contacts a reel 3.

With reference to Figure 3, each sensor 25 comprises an emitter 27 for emitting a beam of electromagnetic waves; and a receiver 28 for receiving a beam of electromagnetic waves. Emitter 27 is located at a distance D1 from receiver 28 and emits a beam so oriented that a surface (face 9 of reel 3) facing, parallel to and located a given distance D2 from annular plate 22 reflects the beam in a position in which receiver 28 is able to pick up the reflected beam. Distance D2 is

measured parallel to axis A and axis 5, and distance D1 is measured perpendicular to axis A. Receiver 28 is defined by a number of adjacent cells 29 sensitive to electromagnetic waves, so that receiver 28 is able to receive the reflected beam when the reflecting surface lies within a given range I (parallel to axes 5 and A) about distance D2. With reference to Figure 2, gripping member 19 is equipped with three sensors 25, the emitters 27 and receivers 28 of which are equally spaced about axis A of cavity 24 of gripping member 19.

With reference to Figure 1, each pin 4a, 4b comprises an expansion spindle 30 having a tapered free end 31, and three sectors 32 movable between a closed position contacting one another, and an open position in which they are forced against spool 6 of a reel 3 to hold reel 3 in a given position about axis 12. As sectors 32 are opened, axis 5 of reel 3 is positioned to coincide with axis 12 of the unwinding pin. In other words, spindle 30 is self-centering.

Feed device 2 is controlled by a control unit 33, which processes the signals from sensors 25 and 26 and controls the movements of manipulator 14, lifting device 20 and pins 4a and 4b.

In actual use, and with reference to Figure 1, a pallet 16 of reels 3 is placed on platform 15. Pallets 16 and reels 3 are of standard size, so that the arrangement of reels 3 on pallet 16 varies within relatively small limits. Consequently, reels 3 on pallet 16 on platform 15

are arranged with a certain tolerance about respective given positions memorized in control unit 33; and, to pick up a reel 3 for supply to machine 1, manipulator 14 positions gripping member 19 over one of reels 3 whose position and height in a vertical direction D are roughly known. Manipulator 14 positions gripping member 19 at or roughly at distance D2 from the top lateral face 9 of reel 3, as shown in Figures 3 and 4.

Given the approximate positions of reels 3, gripping member 19 can be set to the Figure 3 or 4 position, i. e. with axis A of gripping member 19 close to or at hole 7 in reel 3. For the sake of simplicity and to generalize the concept underlying the present invention, gripping member 19 in Figures 3 and 4 is equipped with one distance sensor 25. When gripping member 19 is positioned over reel 3, annular plate 22 is maintained horizontal so as to be parallel to lateral face 9 of reel 3. With reference to the Figure 3 case, emitter 27 emits a beam of electromagnetic waves, which is reflected by lateral face 9 at a given point Kl. Face 9 lying within range I of distance D2 enabling receiver 28 to receive the reflected beam, the reflected beam strikes one of cells 29 of receiver 28, which transmits a signal to control unit 33, which in turn determines the location of reflection point Kl on lateral face 9 of reel 3. When reflection point Kl is located on face 9, gripping member 19 and reel 3 are not sufficiently aligned to ensure reel 3 is positioned correctly on unwinding in 4a, 4b, so

gripping member 19 is moved about its initial position in directions perpendicular to direction D. At each movement, sensor 25 determines whether reflection point Kl lies on lateral face 9 or in hole 7. When the beam enters hole 7, reflection point Kl may be located on a support underneath reel 3 or along an inner face of spool 6. Whichever the case, when the beam enters hole 7, the reflected beam does not strike receiver 28, on account of the reflecting surface not being within range I of distance D2, so that the absence of a receiving signal by receiver 28 combined with an emission signal by emitter 27 indicates gripping member 19 is correctly aligned with reel 3, or at least is aligned sufficiently to ensure correct transfer of reel 3 from gripping member 19 to unwinding pin 4a, 4b.

Manipulator 14 lowers gripping member 19 towards reel 3 in direction D until sensor 26 detects plate 22 contacting lateral face 9; suction holes 23 are then connected to the vacuum source, and reel 3 is raised for transfer to pin 4b; gripping member 19 and reel 3 are positioned over pin 4b so that axis A of member 19 is aligned with axis 12 of pin 4b; gripping member 19 is lowered onto pin 4b in direction D so that pin 4b engages hole 7, even if axis 5 of reel 3 is not perfectly aligned with pin 4b, by virtue of the tapered free end 31 of spindle 30; reel 3 is released by gripping member 19; and spindle 30 is expanded so that axis 5 of reel 3 coincides with axis 12 of unwinding pin 4b.

In other words, before a reel 3 is picked up, a check is made to determine whether reference point Kl of gripping member 19 lies inside hole 7 of reel 3.

Obviously, the more reference points there are, the more accurately and faster hole 7 of reel 3 is determined.

Figures 5,6 and 7 show, schematically, the case in which gripping member 19 comprises three distance sensors 25, as in Figure 2. In Figure 5, three separate reflection points Kl, K2, K3 are located on lateral face 9 of reel 3, which is tantamount to the Figure 3 situation, so that a number of movements about the initial position are required to determine the location of hole 7. This may result in the situation shown in Figure 6, in which two points Kl and K2 are located on lateral face 9, and point K3 lies in hole 7 and is therefore not picked up by receiver 28. Control unit 33, however, knows the hypothetical position of point K3 and commands a movement in the direction of arrow F1, i. e. towards point K3, to also bring points K1 and K2 inside hole 7.

Alternatively, as shown in Figure 7, one point Kl may be located on lateral face 9 of reel 3, and points K2 and K3 inside hole 7. In which case, manipulator 14 moves gripping member 19 in a direction perpendicular to the line joining hypothetical points K2 and K3 and in the direction of arrow F2 until point K1 also lies inside hole 7.

In one variation, control unit 33 does not know the

height of reels 3 in direction D, but only the approximate arrangement of reels 3 in the plane perpendicular to direction D, so that, when positioned over a reel 3, gripping member 19 is lowered into contact with reel 3; and, upon sensor 26 indicating contact between gripping member 19 and reel 3, gripping member 19 is set to or within the range about distance D2 so as to effectively determine the position of gripping member 19 with respect to reel 3, as in the previous case.

The method and device according to the present invention are particularly advantageous by only requiring the processing of a relatively small number of data items.

When the position of gripping member 19 with respect to reel 3 is determined using only one reference point Kl, reel 3 is centered on unwinding pin 4a or 4b by expansion spindle 30. when the position of gripping member 19 with respect to reel 3 is determined using three reference points Kl, K2, K3, axis A of gripping member 19 can be aligned with axis 5 of reel 3 by simply selecting three reference points Kl, K2, K3 located, at distance D2 from a reflecting surface, along a hypothetical circumference slightly smaller in diameter than hole 7, so that reel 3 is transferred to pin 4a or 4b with no need for centering by a self-centering spindle 30. In a further variation not shown, the same result as with three reference points can also be achieved with only two separated, at distance D2 from a reflecting surface, by a distance slightly less than the diameter of the reel hole.