DEVICE FOR FOLDING FLAPS OF BOX-LIKE CONTAINERS

Abstract: A device for folding vertical flaps of a box-like container (1) moved along a line (100) for packaging products (3) into these box-like containers (1) includes a cam-like member (11), guided along a cyclical trajectory (T) by support and operating means (20) cooperating with trajectory correcting means (6). The trajectory (T) includes a first part (T1), along which the cam-like member (11) moves close to container (1), upstream of said rear vertical flap (5) with respect to the container (1) movement direction (W), and a second part (T2), along which the rear vertical flap (5) is pushed. The second part (T2) is substantially parallel to the direction (W) and concordant therewith. The supporting and operating means (20) include a pulley (21) and a connecting rod (22), aimed at guiding the cam-like member (11) and a bar (13), connected thereto, along a circumference arc. The trajectory correcting means (6) include a rotating body (31), aimed at receiving slidingly the bar (13) in a seat (32) made therein.

Description: DEVICE FOR FOLDING FLAPS OF BOX-LIKE CONTAINERS TECHNICAL FIELD The present invention relates to automatic packaging machines. In particular, the present invention concerns a device, which is joined to a machine for packaging products in related box-like containers, and which is capable of folding vertical flaps of the containers during the container closure steps. BACKGROUND OF THE INVENTION It is known that machines for packaging products in boxlike containers withdraw cyclically a flat folded tubular blank from a suitable magazine and erect it, so that it becomes a container. Then these machines place the obtained container on a packaging line, which moves stepwise horizontally and in a determined direction, with a predefined rate. On a parallel way, the products to be packaged, usually already pre-packaged in blister packs, vials or others, are carried to a working station, in step relation with the forward motion of the boxing line. Then the products are introduced into related containers by pusher means . In this step, a typical container is opened at both ends, which are situated on opposite sides with respect to the above mentioned forward motion direction. Each of the apertures formed by the open ends features a pair of vertical flaps, later on called fore flap and rear flap with respect to the above mentioned forward motion direction, and a horizontal flap. After having been folded, these flaps define the container opposite head walls. Usually, in order to facilitate the introduction of the products into the container, the latter is situated on the packaging line in such a way that the horizontal flap of the introduction aperture extends from the upper aperture edge . Generally, the container flaps are closed according to a predetermined sequence by suitable devices, which gradually fold the flaps and bring them close to the container body. In particular, the flaps of the aperture opposite to the products introduction one are closed upstream of the products introduction station, while the flaps of the products introduction aperture are closed downstream of the above mentioned forward motion direction. Various known devices have been used so far for closing the vertical flaps. According to the operation steps of some devices, the fore flap of the container, while moving, strikes a stationary stop, which folds the fore flap and keeps it in the folded position, against the flap tendency to return to its original position due to the elastic reaction, until another closing member, of known type, folds also the horizontal flap. The rear flap is closed by a hinged protruding arm, which folds the rear flap before it reaches the stationary stop and keeps it in the folded position until the outer edge of the rear flap is taken under control by the stop. The above described solution is relatively simple, but it is not very convenient when the container size must be changed. Actually, in this case, the hinged arm must be moved towards upstream, or downstream, in a very precise way, according to the flap size change. Also the hinged arm size must be changed according to the flap size change. Moreover, the vertical position of the arm must be set taking into consideration not only the vertical flap width, but also the possible presence of the horizontal flap joumaled to the aperture upper edge. Another known device for closing vertical rear flaps includes a disc, situated beside the packaging line and featuring a suitably shaped cavity. The disc is driven into rotation in step relation with the container movement, so that the flap enters the above mentioned cavity. At this point, the cavity edge folds the flap. The above described device folds correctly flaps of different width. However, in case of size changeover, the device must be positioned at different distances from the stationary stop accordingly. Moreover, the device vertical position must be changed in relation to the different heights of the flaps of containers of different size, as well as in relation to possible presence of the horizontal flap hinged to the container upper wall. Another closing device includes a plurality of discs, situated one over another. However, this device does not solve the problem due to the every-time-different distance from the stationary stop and to the presence of the horizontal flap hinged to the container upper wall. Another drawback of known folding devices results from the way in which they act on the flaps, rather jerky, sharp movements, which can sometimes damage the flaps. SUMMARY OF THE INVENTION The object of the present invention is to propose a device for closing vertical flaps of a container, e.g. a box-like container, moved along a packaging line, a device which does not present the above mentioned drawbacks and can work with containers of different size, equipped with different flaps. Another object of the present invention is to propose a device, which can be used also with containers having horizontal flaps situated in the lower wall, independently from the container size. A further object of the present invention is to propose a device which is able to fold the rear flaps with a gradual movement, preventing the container from stresses and pushes, thus without leaving traces of the folding operation. Still another object of the present invention is to propose a simple and strong device, which is completely reliable and does not provoke or sustain damages even in case of loss of working synchronism. The above mentioned objects are obtained, in a device for folding vertical flaps of box-like containers being moved in a forward direction along a line for packaging products into the containers, with each container including at least one fore vertical flap and at least one rear vertical flap, which are to be folded toward the inside of a corresponding aperture of the container, so as to define respective head walls of the container, including: at least one stationary striker situated beside said packaging line and in a path of said aperture, for intercepting said fore vertical flap while said container is moving and for folding said fore flap toward the inside of said aperture; folding means for folding said rear vertical flap, situated upstream of said stationary striker with respect to said forward direction, said folding means moving cyclically along a trajectory including at least one first part, in which said foldi-ng means move close to said container, and at least one second part, in which said folding means touch said rear flap and fold it toward inside of said aperture, said first part being substantially perpendicular to said forward direction, upstream of said rear flap, and said second part being substantially parallel to said forward direction and concordant therewith; supporting and operating means for supporting and guiding said folding means along a circumference arc concentric with a first axis; trajectory correcting means guided by said folding means for constraining said folding means while rotating about a second axis, said second axis being substantially parallel to said first axis, with a combination of a shift and rotation movements causing said folding means follow said trajectory; transmission means, aimed at moving said operating means in step relation with the packaging line forward movement . BRIEF DESCRIPTION OF THE DRAWINGS The characteristic features of the invention, not evident from what has just been said, will be pointed out in the following description considered along with the enclosed drawings, in which: - Figure 1 shows a box-like container of known type equipped with horizontal flaps extending from the same panel ; Figure 2 shows another known container equipped with horizontal flaps extending from opposite panels; - Figure 3 is a schematic lateral view of a packaging line, showing the steps in which a container is erected, filled and closed; Figure 4 is a schematic top view of the packaging line of Figure 3; - Figures 5a, 5b and 5c show schematically a preferred embodiment of the proposed device, shown in three different working steps respectively; Figures 5d, 5e and 5f show schematically a series of views corresponding to the ones shown in Figures 5a, 5b and 5c; Figures 6a, 6b and 6c show schematically means for transmitting movement to the device of the Figures 5a, 5b and 5c; Figures 7a and 7b show schematically a different embodiment of the folding device. BEST MODES OF CARRYING OUT THE INVENTION With reference to Figures from 1 to 4 , the reference numeral 1 indicates a box-like container, which is situated on a conveyor 101 of a packaging line 100 of known type. The conveyor moves in a direction W. The container 1 is to be filled with a product 3. The container 1 is obtained, in accordance with a known technique, from a tubular blank, or sleeve, and features at both ends an aperture 6 , 6 ' . A horizontal flap 2 and vertical flaps, namely a fore flap 4 and a rear flap 5 , extend from the edges of the apertures 6, 6'. The flaps are aimed at being folded to form the container bottom walls. In particular, the horizontal flaps 2 can extend from the same lateral wall of the container 1 (see Figure 1) . The container 1 is situated on the conveyor 101 in such a way that its lateral wall without horizontal flaps lies on the operative run of the conveyor. If the horizontal flaps extend from the opposite lateral walls (see Figure 2), a horizontal flap 2', usually the one situated on the end opposite to the product 3 introduction end, extends from the lateral wall lying on the conveyor 101. The vertical flaps, fore 4' and rear 5', corresponding to this last mentioned horizontal flap 2 ' are situated over the same horizontal flap 2 ' . According to a first embodiment, the device for folding the vertical flaps 4, 5 (see Figures 5a to 5c), particularly appropriate to be used when the flaps extend from the same wall, includes a stationary striker 7, situated beside the packaging line 100 and parallel thereto, in the path along which the aperture 6 moves. The striker 7 is aimed at intercepting the fore vertical flap 4 while the container 1 moves in direction W, so as to fold it toward the inside of the aperture 6. The terminal part 7a of the striker 7 is tapered on the side turned toward the aperture 6, so as to facilitate the fore flap 4 folding. Folding means 10 for folding the rear vertical flap 5 are situated downstream of the stationary striker with respect to the movement direction W. The folding means 10 move cyclically along a trajectory T, which schematically includes a first part Tl, along which they move close to the container 1, and a second part T2 , along which they push the rear flap 5 (Figures 5b, 5c) . The first part Tl is approximately perpendicular to the direction W and is situated upstream of the rear flap 5, 5' . The second part T2 is approximately parallel to the direction W and concordant therewith. The folding means 10 include a cam-like member 11, which is situated at the level of the container 1 being transported and which is not higher than the rear vertical flap 5. The cam-like member 11 has a convex lateral surface 11a, a concave surface lib and a linking straight surface lie, with the latter two converging, so as to form a cusp 12 (Figure 5a) . One end of a bar 13 is fastened to the lower surface of the cam-like member 11 in the region of a common rotation center C. Figures 5d to 5f show the cam-like member 11 and the bar 13 offset with respect to cam-like member shown in Figure 5a, 5b and 5c, for obtaining a better graphic clarity. Actually, the cam-like member 11 and the bar 13 are situated one over the other. Supporting and operating means 20, situated under the folding means 10, are aimed at supporting the folding means 10 and at moving them along a circumference arc, substantially horizontal, concentric with a first axis Al. The support and operating means 20 include a horizontal pulley 21 rotating about the first rotation axis Al , and a connecting rod 22. One end of the connecting rod 22 is fastened to the pulley 21 in the region of the first rotation axis Al . The other end of the connecting rod 22 is hinged to the same end of the bar 13, to which the cam-like member 11 is fastened. Trajectory correcting means 30, also fastened to the bar 13, control the position of the folding means 10 while rotating about a second axis A2. The second axis A2 is substantially parallel to the first axis Al . The trajectory correcting means 30 include a body 31, substantially formed by a semi-cylinder, disposed horizontally and rotating freely about the second rotation axis A2. The semi-cylinder 31 features a longitudinal hole or seat 32, substantially horizontal, which intersects the second rotation axis A2. The seat 32 receives slidably the bar 13, so as to block and maintain it in a position, in which it is oriented toward the second rotation axis A2. Therefore, the hinged end of the bar 13, and consequently also the cam-like member 11 are subject to another combined rotation about the second rotation axis A2 during their movement along the circumference arc concentric with the first rotation axis Al . The combination of the above mentioned movement and rotation determines for the cusp 12 a path which advantageously pushes gently the flaps, while the cam- like member follows the trajectory T (Figure 5c) . The proposed folding device includes also transmission means 80 (Figures 6a, 6b, 6c) aimed at driving the pulley 21 and the connecting rod 22, cyclically and alternately, along the circumference arc, in step relation with the operation of the packaging line 100. The transmission means 80 include a disc 81, driven into continuous rotation by known and not shown motor means, in a rotation direction Wl . One end 82a of a chain 82 engaging with the pulley 21 is fastened to a joining point 81a made in the edge of the disc 81. The other end of the chain 82 is fastened to an end of a spring 83. The other end of the spring 83 is fastened to a stationary support 84, situated near the disc 81. Therefore, the chain 82 and the spring 83 assume substantially a "U" shape wound around the pulley 21. The above described layout allows to transform the continuous rotating movement of the disc 81 into a reciprocation movement of predetermined amplitude of the chain 82 and into a partial and alternate rotation of the pulley 21. The length of the chain 82 is such that, when the joining point 81a is situated at the minimum distance from the pulley 21, the spring 83 is unloaded, and when the joining point 81a is in the opposite position, the spring is fully tensioned. Operation of the proposed device according to the first embodiment is described beginning from the configurations shown in Figures 5a and 6b, which show substantially synchronous steps . In these Figures, a container 1 moves on the packaging line 100 and the fore vertical flap 4 of the container is engaged by the stationary striker 7, while the rear vertical flap 5 is still open. The conveyor 101 usually moves stepwise and in these configurations is dwelling. The joining point 81a of the disc 81 is situated at the maximum distance from the pulley 21, and consequently, the spring 83 is under tension. The connecting rod 22 is in a first dead center PI and the cam-like member 11 is at a point Ta of the trajectory T, which is at a maximum distance from the container 1. The cam-like member 11 orientation is defined by the constraint made by the body 31 on the rod 13. The cusp 12 is turned outward of the packaging line 100. The progressive rotation of the disc 81 in the direction Wl allows the spring 83 to act elastically on the chain 82, thus making the pulley 21 rotate in a direction Xa (Figure 6c) . This makes the cam-like member 11 move along the circumference arc centered on the first rotation axis Al and rotate counterclockwise due to the bar 13 sliding in the seat 32 of the body 31 (Figure 5b) . Therefore, the cam-like member 11 covers only the part Tl of the trajectory T (Figure 5b) , which brings it close to the container 1, upstream of the rear vertical flap 5, until the cusp 12 touches the latter. Further rotation of the disc 81, until the joining point 81a reaches the position in which it is at a minimum distance from the pulley 21, allows the spring 83 to become completely released (Figure 6a) and allows the pulley 21 to reach a second dead center P2 (Figure 5c) . Meanwhile, the cam-like member 11 covers the part T2 of the trajectory T, which provokes a further counterclockwise rotation of the cam-like member 11 about the second rotation axis A2. Thus, the cusp 12 engages progressively the rear vertical flap 5 with the straight surface lie and folds it toward the inside of the aperture 6. At this point, the conveyor 101 is operated so as to allow the so folded rear flap 5 to be moved forward, until it is engaged by the stationary striker 7. The disc 81 continues to rotate and the joining point 81a moves far from the pulley 21 (Figure 6a, indicated with broken line) , thus making the pulley rotate in a direction Xb, opposite to the direction Xa, until the joining point 81a reaches its maximum distance from the pulley shown in Figure 6b. Meanwhile, the cam-like member 11 covers the trajectory T backwards and returns to its initial position, so as to perform another folding cycle. It is to be pointed out that the above described layout allows to perform the folding active step due to the elastic action of the spring 83 and therefore, it is not bound to rigid mechanical transmissions. This increases considerably the device safety and reliability, since inconveniences which can occur during folding operations do not damage the device or other elements of the system. Another embodiment of the proposed folding device is shown in Figures 7a, 7b. This embodiment is preferred when the horizontal flap 2', situated on the side opposite to the product 3 introduction side, extends from the lateral wall lying on the conveyor 101. In this case, the device includes folding means 50 which comprise an arm 51, situated beside the feeding line 100 and crosswise thereto, at the height of the vertical flaps 4' , 5' . The arm 51 is aimed at acting on the flap 5', so as to fold it. One end of the arm 51 is pivoted to a driving connecting rod 62 of the supporting and operating means 60, and the other end features a prong 52. The prong 52 extends toward the rear flap 5 ' . The arm 51 includes a stationary part 51a and a changeable part 51b. One end of the changeable part 51b is removably fastened to the stationary part 51a and carries a prong 52 (Figure 7b) at a free end. The supporting and operating means 60 include also a pulley 61, situated horizontal and rotating about a first rotation axis Al ' . The driving connecting rod 62 is fastened to the pulley 61 in the region of the first rotation axis Al ' . The proposed device according to the second embodiment includes also trajectory correcting means 70, comprising a correcting connecting rod 71, rotating freely about a second rotating axis A2 ' , parallel to the first rotation axis Al ' . The correcting connecting rod 71 is hinged to a bracket 53 which extends laterally from the arm 51. The action of the transmission means 80 on the supporting and operating means 60 of the device according to the second embodiment is analogous to the already described operation thereof in the device made according to the first embodiment. The operation of the device made according to the second embodiment is described beginning from the configuration indicated by broken line with longer sections of Figure 7a. The arm 51 is in a rest position Pr, corresponding to a position of a first dead center PI of the pulley 61. The fore vertical flap 4' has already been intercepted and folded by the stationary striker 7 ' and the conveyor 101 is in a dwelling. The pulley 61 is rotated in direction Xc, and the hinged end of the arm 51 follows a circumference arc concentric with the first rotation axis Al ' , which moves the prong 52 close to the container 1. The movement of the bracket 53 depends on a rotation about the second axis A2 ' , imposed by the correction connecting rod 71, which moves the prong 52 towards upstream (position Pa' indicated with broken line in Figure 7a) . Subsequently, the arm 51 continues to move close to the container 1 and is pulled towards downstream by the correcting connecting rod 71 (position Pa'' of Figure 7a) . During this movement, the prong 52 gets in contact with the rear flap 5', from upstream to downstream, and folds it toward the inside of the corresponding aperture 6'. Finally, the pulley 61 reaches the second dead center P2, thus bringing the prong 52 to a position Pa' ' ' (Figure 7b), parallel to the conveyor 101, in which the prong 52 maintains the rear flap 5' in folded position. Then, the conveyor 101 is moved until the flap 5' just mentioned is engaged by the stationary striker 7'. The device made according to the present invention is much more efficient and versatile with respect to the prior art. The main advantage of the present invention derives from the possibility to work with a wide range of the container 1 having different sizes. In fact, the cam-like member 11 or the arm 51 trajectory includes a part along which the cam-like member 11 or the arm 51 follows the rear vertical flap from upstream to downstream, which allows to intercept also the flaps arranged in a different way, without a necessity of repositioning of the cam-like member or the arm, which also avoids the packaging machine adjustments. Another advantage of the present invention results from the rear flaps progressive folding and following action, which allows to avoid the damages to the flaps. A further advantage of the present invention, obtained by the second embodiment, lies in the fact that the proposed folding device can be used also when the horizontal flaps are situated in the lower wall of the container, independently from the container size. Yet further advantage of the present invention derives from the fact that the proposed device is safe and is operated in a simple and efficient way. It is understood that what above has been described as a pure, not limiting example, therefore possible modifications or variants of the invention remain within the protective scope of the present technical solution as claimed hereinafter.

Claims: CLAIMS 1. A Device for folding vertical flaps of box-like containers, the containers (1) being moved in a forward direction (W) along a line (100) for packaging products (3) into the containers (1), each container (1) including at least one fore vertical flap (4,4') and at least one rear vertical flap (5,5'), which are to be folded toward the inside of a corresponding aperture (6,6') of the container, so as to define respective head walls of the container (1) , said device being characterized in that it includes : at least one stationary striker (7,7') situated beside said packaging line (100) and in a path of said aperture (6,6'), for intercepting said fore vertical flap (4,4') while said container is moving and for folding said fore flap (4,4') toward the inside of said aperture (6,6'); folding means (10,50) for folding said rear vertical flap (5,5'), situated upstream of said stationary striker (7,7') with respect to said forward direction (W) , said folding means (10,50) moving cyclically along a trajectory (T) including at least one first part (Tl) , in which said folding means move close to said container (1) , and at least one second part (T2) , in which said folding means (10,50) touch said rear flap (5,5') and fold it toward inside of said aperture (6,6'), said first part (Tl) being substantially perpendicular to said forward direction (W) , upstream of said rear flap (5,5'), and said second part (T2) being substantially parallel to said forward direction (W) and concordant therewith; supporting and operating means (20,60) for supporting and guiding said folding means (10,50) along a circumference arc concentric with a first axis (Al,Al'); trajectory correcting means (30,70) guided by said folding means (10,50) for constraining said folding means (10,50) while rotating about a second axis (A2,A2'), said second axis (A2,A2') being substantially parallel to said first axis (A1,A1'), with a combination of a shift and rotation movements causing said folding means (10,50) follow said trajectory (T) ; transmission means (80), aimed at moving said operating means (20,60) in step relation with the packaging line (100) forward movement. 2. A device, according to claim 1, wherein said folding means (10) include: a cam-like member (11) in height shorter than, or at least equal to, said rear vertical flap (5) , for intercepting said rear vertical flap (5) while following said second part of said trajectory (T) ; and a substantially horizontal bar (13) with one fastened to a lower surface of said cam-like member (11) in the region of a common rotation center (C) , and hinged to said support and operating means (20), said bar (13) being also fastened to said trajectory correcting means (30) . 3. A device, according to claim 2, wherein the edge of said cam-like member (11) is defined by a convex surface (11a) , a concave surface (lib) , and a linking straight surface (lie) , with said concave surface (lib) and straight surface (lie) converging, so as to form a cusp (12) . 4. A device, according to claim 1 wherein said supporting and operating means (20) include a pulley (21) , rotating about said first rotation axis (Al) , and a connecting rod (22) with one end fastened to said pulley (21) in the region of said first rotation axis (Al) and with another end carrying said bar (13) hinged thereto. 5. A device, according to claim 1, wherein said trajectory correcting means (30) include a body (31), rotating about said second rotation axis (A2) and featuring a longitudinal substantially horizontal seat (32) intersecting said rotation axis (A2), said seat (32) being aimed at receiving slidably said bar (13) . 6. A device, according to claim 1, wherein said folding means (50) include: an arm (51) , situated beside said packaging line (100) and oriented crosswise thereto, at a height level of said vertical flaps (4', 5'), with one end of said arm (51) pivoted to said supporting and operating means (60) , and another end of said arm (51) equipped with a prong (52) extending toward said rear flap (5') for pushing said rear flap (5') toward the aperture (6'). 7. A device, according to claim 6, wherein said supporting and operating means (60) include: a pulley (61) rotating about said first rotation axis (Al' ) ; and a driving connecting rod (62) having one end fastened to said pulley 861) in the region of said first rotation axis (Al ' ) and another end pivoted to said arm (51) . 8. A device, according to claim 6, wherein said trajectory correcting means (70) include a correction connecting rod (71) , rotating freely about said second rotation axis (A2 ' ) , pivoted also to a bracket (53), which extends laterally from said arm (51) . 9. A device, according to claim 6, wherein said arm (51) include a stationary part (51a) and a changeable part (51b) , whose one end is removably fastened to said stationary part (51a) whose other end carries said prong (52) . 10. A device, according to claim 1, wherein said transmission means (80) include: a disc (81), driven into continuous rotation in a direction (Wl) ; a chain (82) , whose one end (82a) is linked to the edge of said disc (81) and is aimed at engaging a corresponding pulley (21,61) of said supporting and working means (20,60); a spring (83), fastened to the other end (82b) of said chain (82) and to a stationary support (84); said disc (81) being aimed at guiding said chain (82) in reciprocating motion of predetermined amplitude, against the elastic action of said spring (83) .

Inventors: GAUDENZI RODOLFO, GAUDENZI, RODOLFO
Applicants: GAUDENZI RODOLFO, IMA SPA, GAUDENZI, RODOLFO, I.M.A. INDUSTRIA MACCHINE AUTOMATICHE S.P.A.
Application year: 2000
Main classification: B65B7
IPC codes: B65B7, B65B49