Unit for supplying blanks on a packing machine

Abstract: A unit (3) for supplying blanks (4) on a packing machine (2), wherein a wheel (16), rotating about a respective axis (18), continuously feeds a blank pickup head (19) along an endless path (P) through a loading station (S1) where the pickup head (19), oscillating with respect to the wheel (16) about an axis (24) parallel to the axis (18) of the wheel (16), engages a bottom opening (13) of a blank store (9) to withdraw a blank (4), and then through an unloading station (S2) where the pickup head (19), rotating together with the wheel (16), feeds the blank (4) onto a conveyor roller (6).

Description: The present invention relates to a unit for supplying blanks on a packing machine. In the following description, reference is made purely by way of example to packing machines for producing rigid packets of cigarettes. Units for supplying blanks on cigarette packing machines, such as the one described for example in US-A-5,029,834, comprise a suction pickup head moved cyclically by a crank mechanism substantially back and forth between a pickup position, in which the head engages a bottom opening in a blank store to withdraw a blank, and an unloading position, in which the head feeds the blank onto a conveyor roller. Though perfectly satisfactory, supply units of the type described above fail to meet the high operating speeds (over 600 packets a minute) demanded by modern cigarette packing machines, owing to the inertia and vibration produced by the substantially reciprocating movement of the pickup head. FR-A-2,478,576 discloses a packing machine having a unit for supplying blanks and comprising a store for storing blanks, the store having a bottom opening, a pickup head for withdrawing a respective blank and located on a plate connected to a wheel rotating continuously about a first axis to feed the pickup head along an endless path extending through a loading station where the pickup head engages the bottom opening to withdraw a blank. The plate is connected to the wheel to oscillate, with respect to the wheel, about a second axis parallel to the first axis by means of an actuating device. The supplying unit disclosed in the aforementioned FR-A-2,478,576 is capable to operate at a speed higher than that of the supplying unit disclosed in US-A-5,029,834, but is not capable to operate with satisfactory results at the high operating speeds (over 600 packets a minute) demanded by modern cigarette packing machines owing to the fact that, at such speed, the pickup head, by moving in a substantially radial direction in relation to the wheel, is not given a sufficient time to properly engage the blank to be withdrawn. It is an object of the present invention to provide a unit for supplying blanks on a packing machine, which is straightforward and cheap to produce, provides for eliminating the aforementioned drawback, and therefore enables high operating speed. According to the present invention, there is provided a unit for supplying blanks on a packing machine as recited in the attached claims. A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a schematic, partially sectioned front view, with parts removed for clarity, of a preferred embodiment of the unit according to the present invention; . Figures 2, 3 and 4 show respective details of Figure 1; Figure 5 shows a further detail of Figure 1 in a different operating position. Number 1 in Figure 1 indicates as a whole a supply section of a packing machine 2, comprising a unit 3 for supplying blanks 4 to respective suction seats 5 defined on the outer periphery of a conveyor roller 6, which is rotated continuously (anticlockwise in Figure 1) about a fixed central axis 7 perpendicular to the Figure 1 plane by a powered shaft 8. Unit 3 comprises a store 9 having a central axis 10 in the Figure 1 plane, and housing a stack 11 of substantially rectangular blanks 4. Store 9 extends in a substantially vertical plane, and comprises a bottom portion 12 having a substantially rectangular bottom opening 13 with two teeth 14 fitted to store 9 by respective bolts 15 to retain stack 11 of blanks 4 inside store 9 in opposition to the force of gravity. Unit 3 also comprises a wheel 16, which is rotated at constant speed (clockwise in Figure 1) by a powered shaft 17 having a fixed first axis 18 parallel to axis 7 and crosswise to axis 10, and supports a number of suction pickup heads 19 equally spaced about axis 18. The continuous rotation of wheel 16 about axis 18 feeds each pickup head 19 along an endless path P through a loading station S1, where pickup head 19 engages bottom opening 13 to withdraw a respective blank 4 at opening 13, and through an unloading station S2 where pickup head 19 feeds the withdrawn blank 4 to a respective seat 5 on conveyor roller 6. Each pickup head 19 is connected mechanically to wheel 16 by the interposition of a respective actuating device 20, which, as pickup head 19 travels through loading station S1, moves pickup head 19 tangentially with respect to the periphery of wheel 16 to keep pickup head 19 facing bottom opening 13 for a long enough time interval to complete withdrawal of a respective blank 4 at opening 13. Within the same time interval, actuating device 20 moves pickup head 19 radially with respect to wheel 16 to enable pickup head 19 to withdraw blank 4 from bottom opening 13. As pickup head 19 travels through unloading station S2, actuating device 20 sets pickup head 19 to a fixed position substantially tangential with respect to the periphery of wheel 16 to feed the withdrawn blank 4 to a respective seat 5. Each actuating device 20 comprises a plate 21 having an end 22 located at the front in the traveling direction of pickup head 19 and at which respective pickup head 19 is fitted, and an end 23 opposite end 22 and at which plate 21 is hinged at second axis 24 to one end of an arm 25, the opposite end of which is hinged to wheel 16 by a pin 26 defining a third axis 27 and is oscillated, with respect to wheel 16, about said axis 27 by a cam control device 28 (shown in Figure 3). At an intermediate portion between ends 22 and 23, each plate 21 is hinged at 29 to one end of an arm 30, which is connected mechanically at the opposite end to a cam control device 31 (shown in Figure 2) and is moved by device 31 substantially radially with respect to wheel 16. As shown in Figure 2, each control device 31 comprises a fixed cam 32 extending about axis 18 and cooperating with a follower device 33, which comprises a carriage 34 having two parallel tappet rollers 35 engaging opposite sides of cam 32. Carriage 34 is hinged to wheel 16 by a pin 36 so as to oscillate, with respect to wheel 16, about an axis 37 parallel to axis 18, and defines a first arm of a rocker arm pivoting on wheel 16 at axis 37 and comprising a second arm 38, the end of which, opposite the end integral with carriage 34, is hinged at 39 to a free end of a respective arm 30. As wheel 16 rotates about axis 18, the profile of cam 32 causes each carriage 34 and respective arm 38 to oscillate about axis 37 and so move respective arm 30 substantially radially with respect to wheel 16, which radial movement of arm 30 in turn causes respective plate 21 to oscillate with respect to respective arm 25 about respective second axis 24 and so move respective pickup head 19 substantially radially with respect to wheel 16. As shown in Figure 3, each control device 28 comprises two fixed cams 40 extending about axis 18, offset axially with respect to each other, and cooperating with a follower device 41, which comprises a carriage 42 having two tappet rollers 43, each engaging a respective cam 40. Carriage 42 is hinged to wheel 16 by a pin 44 to oscillate, with respect to wheel 16, about an axis 45 parallel to axis 18, and is connected mechanically to one end of respective arm 25 by means of a crank mechanism 46. Each crank mechanism 46 comprises an arm 47 which, together with respective arm 25, defines a rocker arm pivoting on and oscillating with respect to wheel 16 about axis 27. Crank mechanism 46 also comprises an arm 48 connected at one end to arm 47 by a hinge 49, and at the other end to carriage 42 by a hinge 50. As wheel 16 rotates about axis 18, the profiles of cams 40 cause each carriage 42 to oscillate about respective axis 45; the movement produced by the oscillation of carriage 42 is transmitted by respective arm 48 to arm 47 to oscillate arm 47 and respective arm 25 about respective axis 27; and, given the small distance between axes 27 and 18, as shown clearly in Figure 3, the oscillation of arm 25 about respective axis 27 causes respective plate 21 and hence respective pickup head 19 to move substantially tangentially with respect to the periphery of wheel 16. As shown in Figure 4, unit 3 comprises a suction device 51 connected pneumatically to one end 52 of an inner conduit 53 (Figure 1) of each pickup head 19 to generate suction through head 19 to retain a respective blank 4 on head 19 as head 19 travels from loading station S1 to unloading station S2. Suction device 51 comprises a fixed central distributor 54 housed coaxially in wheel 16 and having a chamber 55, which is formed in the outer periphery of distributor 54 and divided into two contiguous, pneumatically isolated sections 56 and 57 located respectively at stations S1 and S2. Each section 56, 57 is connected to a suction pump 58 by a respective valve 59 controlled by a control device 60. Suction device 51 also comprises a tubular body 61, which is coaxial and rotates with wheel 16, cooperates with distributor 54, and has, for each pickup head 19, a through hole 62 connected pneumatically at one end to distributor 54 and at the other end to respective end 52 by a conduit 63. As wheel 16 rotates about axis 18, each hole 62 communicates with section 56 as respective pickup head 19 travels through loading station S1, and then communicates, substantially seamlessly, with section 57 as respective pickup head 19 travels through unloading station S2. The angular extension of sections 56, 57 is such as to activate suction through each pickup head 19 as pickup head 19 starts to engage bottom opening 13 of store 9, and to cut off suction as pickup head 19 faces a respective seat 5 on conveyor roller 6. Operation of unit 3 will now be described with reference to one pickup head 19 and as of the instant in which pickup head 19 leaves unloading station S2. As wheel 16 rotates continuously, pickup head 19 is fed through loading station S1 where respective actuating device 20 moves pickup head tangentially, i.e. substantially along path P, with respect to wheel 16 to keep head 19 facing bottom opening 13 of store 9 for a long enough time interval to complete withdrawal of a respective blank 4 at opening 13. During the same time interval, actuating device 20 also moves head 19 radially with respect to wheel 16 by means of said oscillation about respective axis 24 to bring head 19 into contact with blank 4, which adheres to head 19 by virtue of the suction produced, as described, by suction device 51. As shown in Figure 5, once blank 4 adheres to head 19, actuating device 20 withdraws head 19 from bottom opening 13 by means of said oscillation about respective axis 24; which oscillation deforms and enables an edge 64 of blank 4 to slip over the front tooth 14 in the traveling direction of head 19 along path P. At the end of the radial movement of head 19, actuating device 20 arrests the tangential movement of head 19, which is once more fed along path P by the continuous rotation of wheel 16 about axis 18; and, as head 19 travels along path P, and edge 65 of blank 4 is withdrawn from beneath the rear tooth 14 in the traveling direction to complete withdrawal of blank 4 from bottom opening 13. As wheel 16 rotates continuously, head 19 is then fed through unloading station S2 where actuating device 20 sets pickup head 19 to a fixed position substantially tangential with respect to wheel 16 to feed the withdrawn blank 4 to a respective seat 5 traveling through unloading station S2 together with and substantially tangent to pickup head 19. Blank 4 is transferred from pickup head 19 to respective seat 5 by simply cutting off suction, as described, through pickup head 19 and simultaneously activating suction through seat 5. To ensure blank 4 adheres completely to seat 5, provision is made downstream from unloading station S2 for a fixed circular section 66 substantially tangent to seat 5. The above steps are repeated cyclically. During normal operation of packing machine 2, a known control unit (not shown) of machine 2 may signal to control device 60 not to supply a blank 4 to conveyor roller 6 on account, for example, of the corresponding product (not shown) having been rejected. In this case, control device 60 first acts on valve 59 of section 56 to temporarily cut off suction at section 56 and so prevent the pickup head 19 at loading station S1 from withdrawing a blank 4, and to maintain suction at section 57 to enable the previous pickup head 19 traveling towards unloading station S2 to retain the respective blank 4. Control device 60 then acts on valve 59 of section 57 to temporarily cut off suction at section 57 and so prevent suction from being activated through an empty pickup head 19, and to maintain suction at section 56 to enable the next pickup head 19 to withdraw a respective blank 4.

Claims: A unit (3) for supplying blanks on a packing machine, the unit (3) comprising a store (9) for storing blanks (4) and having a bottom opening (13); a plate (21) having a first end and a second end (22, 23) opposite each other; a pickup head (19) for withdrawing a respective blank (4) and located on the plate (21), close to the first end (22); a wheel (16) rotating continuously about a first axis (18) to feed the pickup head (19) along an endless path (P) extending through a loading station (S1) where the pickup head (19) engages the bottom opening (13) to withdraw a said blank (4); and an actuating device (20) having a first actuator (30, 38, 31) to oscillate the plate (21), with respect to the wheel (16), about a second axis (24) extending through the second end (23) and parallel to the first axis (18); the unit characterized in that the actuating device (20) has a second actuator (25, 46, 28) to move the plate (21) substantially tangentially with respect to the wheel periphery (16) and comprising an arm (25) connected to the plate (21) and oscillating with respect to the wheel (16) about a third axis (27) parallel and close to the first axis (18). A unit as claimed in Claim 1, wherein the first end and the second end (22, 23) are aligned along the path (P); the first end (22) being a front end in a traveling direction of the pickup head (19) along the path (P). A unit as claimed in Claim 1 or 2, wherein the actuating device (20) is connected to the plate (21) at an intermediate point between the first end and the second end (22, 23). A unit as claimed in Claim 3, wherein the actuating device (20) comprises a first transmission (30, 38) connected to the plate (21); and first cam control means (31) connected to the first transmission (30, 38) to control the angular position of the plate (21) about the second axis (24). A unit as claimed in Claim 4, wherein the first cam control means (31) comprise a fixed first cam (32) extending about the first axis (18); and a first follower device (33) cooperating with the first cam (32) and having a first carriage (34) hinged to the wheel (16) to oscillate, with respect to the wheel (16), about a fourth axis (37) parallel to the first axis (18); the first transmission (30, 38) comprising a first arm (30), which is hinged at one end to the plate (21) at the intermediate point, and is hinged at the opposite end to the first carriage (34) via a second arm (38) angularly integral with the first carriage (34). A unit as claimed in any one of Claims 1 to 5, wherein the actuating device (20) comprises a second transmission (25, 46) connected to the plate (21); and second cam control means (28) connected to the second transmission (25, 46) to control the angular position of the plate (21) about the third axis (27). A unit as claimed in Claim 6, wherein the second cam control means (28) comprise two fixed cams (40) extending about the first axis (18); and a second follower device (41) cooperating with the two fixed cams (40) and having a second carriage (42) hinged to the wheel (16) to oscillate about a fifth axis (45) parallel to the first axis (18); the second transmission (25, 46) comprising a third arm (25), which is hinged at one end to the plate (21) to oscillate, with respect to the plate (21), about the second axis (24), and is hinged at the opposite end to the wheel (16) to oscillate, with respect to the wheel (16), about the third axis (27). A unit as claimed in Claim 7, wherein the second transmission (25, 46) comprises a fourth arm (47) angularly integral with the third arm (25) ; and a fifth arm (48) hinged at one end to the second carriage (42) and at the opposite end to the fourth arm (47). A unit as claimed in any one of Claims 1 to 8, further comprising a conveyor roller (6) rotating continuously about a sixth axis (7) and substantially tangent to the wheel (16) at an unloading station (S2) where the blank (4) is unloading off the wheel (16); and a suction device (51) connected pneumatically to the pickup head (19) to generate suction through the pickup head (19) as the pickup head (19) travels from the loading station (S1) to the unloading station (S2). A unit as claimed in Claim 9, wherein the suction device (51) comprises a suction pump (58); a central fixed distributor (54) housed coaxially in the wheel (16) and having a chamber (55) formed in the outer periphery of the fixed distributor (54) and divided into two contiguous, pneumatically isolated sections (56, 57); a tubular body (61) integral and coaxial with the wheel (16), cooperating with the fixed distributor (54), and having a hole (62) connected pneumatically to the pickup head (19) to pneumatically connect, in use, the pickup head (19) to the fixed chamber (55); and two valves (59) for respectively connecting the pump (58) to the two sections (56, 57); a first (56) of the two sections being located at the loading station (S1), and a second (57) of the two sections being located at the unloading station (S2).

Inventors: BRINTAZZOLI ROBERTA, MINARELLI ALESSANDRO, OSTI ROBERTO, BRINTAZZOLI, ROBERTA, MINARELLI, ALESSANDRO, OSTI, ROBERTO
Applicants: GD SPA, G.D SOCIETA' PER AZIONI
Application year: 1999
Main classification: B65B19
IPC codes: B65B43, B65B19