METHOD AND APPARATUS FOR THE FASTENING OF THE TAIL OF WRAPPINGS OF STRETCHABLE FILM FOR PALLETIZED LOADS

Abstract: In a wrapping machine for wrapping palletized loads (C) with stretchable film having an elastic memory, when the wrapping of the load is about to be completed, distancing means (143) are placed close to the wrapped load, on which distancing means a part of at least the last wrapping turn (S1) rests, so that a pocket (T) of proper size is formed in said turn. The carriage of the wrapping machine is stopped in a predetermined angular position and the film tail aligned and properly placed in respect of a main clamp and a secondary clamp (P1-P2). Subsequently, cutting means (18) cut the film between said two clamps, and the main clamp (P1) holding the leading end of the film coming from the wrapping machine carriage moves backward at rest. The other clamp (P2) holding the tail end of the wrapping film is introduced into said pocket (T) and then said secondary clamp opens and is drawn out from said pocket together with the means (143) that formed the pocket, so that the wrapping tail gets caught and blocked by friction in the last turn of the wrapping which shrinks flat because of its elastic memory.

Description: TITLE: "Method and apparatus for the fastening of the tail of wrappings of stretchable film for palletized loads" DESCRIPTION The invention relates to a method and apparatus for wrapping palletized loads with stretchable film or other elastic and/or plastic material which owing to the elastic memory of the said wrapping film ensures tight wrappings safely securing the load. The invention can be applied to any known wrapping machine, for instance those in which the load is caused to rotate about a vertical axis, or those in which the load is fixed and the wrapping film feeding equipment rotates around the load itself with an alternate vertical motion at the same time, to make sure the load is tightly wrapped all along its height. The latter machines may be either the type wherein the carriage holding the film reel and pre- stretching rollers rotates on a ring with a vertical or horizontal axis that alternatively moves along such axis, or the type wherein the reel and pre- stretching rollers are mounted so as to be able to move vertically onto the upright of an upside-down "L" arm whose upper end can swing around a vertical axis and is supported by a portal structure below which the load to be wrapped is placed. In these types of equipment the wrapping film leading end is generally held by a fixed clamp placed to the side of the load to be wrapped which opens when the first turns of the wrapping film are overlapped and self-blocked. The wrapping film leading end is so blocked by friction onto the load and into the wrapping itself, which is a solution extremely reliable as well as quick and easy to realize. Once the wrapping is completed, the film tail is then heat-sealed to the wrapping itself by an external heated plug or by a welder and a counter-welder which is temporarily drawn near the load so as to be then surmounted by the final turns of the wrapping and is then withdrawn on completion of heat-sealing. The heat-sealing of the tail takes some time also because of the cooling that must follow the heating of the material to be heat-sealed and is often a rather difficult operation to be performed owing to the poor consistency of the stretchable film to be heat-sealed. In addition, the final wrapping turns must be arranged in such a way that their consistency and arrangement are suitable for undergoing heat- sealing, which implies a rather difficult operation. Moreover, heat-sealing produces harmful gases which are let out in the ambient air. The invention provides a new method and the related apparatus to fasten the wrapping film tail consisting of: - placing near one side of the load some means on which the final turn/turns of the wrapping rests/rest transversally so as to form a pocket of the correct size in the wrapping wherein such turns are properly spaced from the load; - holding the film, in the zone of the wrapping tail, with a main clamp and a secondary clamp, the said two clamps being not far from each other, the secondary clamp being closer to the load; - cutting the film between two said clamps so as to identify the wrapping tail held by the secondary clamp and the leading end of the subsequent turn held by the main clamp; - placing the secondary clamp holding the wrapping tail into said pocket and then opening such clamp and removing it from such pocket, such operation being correctly phased with the removal of the means that formed the pocket, so that the pocket, owing to the elastic memory of the wrapping film, will shrink and spread flatly quickly and the length of the film that formed it will incorporate and firmly hold the wrapping tail with no need for heat-sealing. Thus is the wrapping tail becomes friction-blocked by the wrapping itself. More detailed features of the method and the related apparatus, described by way of example in a ring wrapping machine, but that can be adapted to any type of wrapping equipment, will be given in the following description of some preferred embodiments in the figures of the attached sheets of drawings, in which: - Figure 1 shows a perspective view of the apparatus with some components at rest and some other components working; - Figure 2 shows a side view with sectioned parts of the main clamp; - Figure 3 shows the perspective of the end part of the main clamp; - Figure 4 shows a side view with sectioned parts of the film cutting assembly mounted to said main clamp; - Figure 5 shows a schematic side view of the position of the main clamp, the film reel with the pre-stretched and load film rolls at the beginning of a wrapping cycle; - Figures 6, 7, 8, 9, 10, 11 , 12, 13 show perspective views of as many corresponding subsequent phases of a working cycle of the apparatus; - Figure 14 is a side elevation view of another embodiment of the secondary clamp; - Figure 15 is a side elevation view of another embodiment of the means for forming a pocket in the turns of the wrapping; - Figure 16 is a top view of the means of Figure 15; - Figures 17, 18, 19, 20, 21 and 22 show in perspective view as many corresponding steps of a working cycle adopting the means shown in Figures 14, 15 and 16. From Figure 1 it can be seen that the apparatus is mounted to the annular frame (not shown) of a ring-type wrapping machine on which the carriage with the reel and the pre-stretching rollers move, and, for instance, is placed laterally to the path of the load to be wrapped and above the orbit covered by the said carriage. The apparatus is composed of a carrier formed by a horizontal beam 1 parallel to the path of the load to be wrapped and carrying at its ends 101-101' the wheels 2-2' partly grooved and partly smooth that run on parallel guide bars 3-3' longitudinally fixed to beams 4-4' perpendicular to said carrier 1 and fixed to the annular frame on which the carriage with the film reel and pre- stretching rollers runs. Longitudinally fixed to beams 4-4' are racks 5-5' which mesh with pinions 6-6' splined to the ends of a rotating shaft 7 which traverses carrier 1 longitudinally, so that the latter can properly move along said guide bars 3-3' even when operated through one only end, for instance through the linkage between one of its appendixes 201 and the pneumatic cylinder 8 whose body is secured to beam 4. Fixed underneath carrier 1 in an intermediate position is an upside-down "L" support 9 bearing a horizontal pin 10 appropriately converging towards the center line of said carrier 1. Mounted to said pin 10 is the rotating end of a telescopic arm 11 provided with a side appendix 12 projecting from said pin 10 and to which the stem of a pneumatic cylinder 13 is articulated, the body of said cylinder 13 being fulcrum-attached to an arm 14 projecting from carrier 1. Upon operating cylinder 13, arm 11 can move from the vertical position shown in fig. 1 to a horizontal position, approaching beam 4' (see hereinafter). The arm 11 is composed of a body 111 within which an inner member 211 slidably is mounted by means of guide-slide assemblies 15 (fig. 2) whose lower end is provided with an appendage 16 linked to the stem of a pneumatic cylinder 17 fulcrum-attached to body 111. Upon operating cylinder 17, arm 11 can change from the condition wherein inner sliding member 211 is retracted within body 111 to the condition wherein it extends as shown in figs. 1 and 2. The inner sliding member 211 is less wide than body 111 so that a portion of such body, which is opposite the side towards the rotation orbit of the film reel, is free for all its entire height and a small arm 18 perpendicular to fulcrum 10 can move within it. An end of said fulcrum 10 is provided with a preferably saw-toothed blade 18 protruding from a longitudinal slit 19 cut in the lower wall of said body 111 which is turned downward when arm 11 is at rest in a horizontal position. The other end of said fulcrum 10 goes through a similar slit 20 cut in the opposite wall of same body 111 and of a tubular guide bar 21 fixed to said body, and is attached to a carriage 22 linked to the stem of a pneumatic cylinder 23 placed to the side of cylinder 17 and fulcrum-attached to body 111. When the apparatus is at rest, blade 18 rests at the lower end of body 111 , as shown in fig. 4 with a solid line, the same blade being hidden within a domed protection cap shown in figs. 3 and 4. Upon operating cylinder 23, blade 18 lifts and takes the position shown in fig. 4 with a dashed line. Articulated in 25 on the free end of sliding member 211 and parallel to fulcrum 10 is a bell crank 26 which through one of its arm 126 protrudes from the wall of the inner sliding member turned towards blade 18, while through the other arm 226, within the inner sliding member itself, it is articulated to the stem of a pneumatic cylinder 27 fulcrum- attached within the inner sliding member 211 itself. Upon operating cylinder 27, bell crank 26 moves from the position shown in figs. 2 and 3 with a solid line to the position shown with a dashed line. The outer arm 126 of bell crank 26 forms the main part of the movable jaw of the main clamp P1 holding the wrapping film, and for this reason its active surface is coated with a strip 28 of an elastomeric material characterized by a high friction factor in respect of the film, while fixed to the opposite side of jaw 126 is a small U-shaped case 29 on which fixed to its sides are suitably shaped metal rods 30 and 31 described hereinafter. As shown in fig. 1 , provided on the intermediate part of carrier 1 are grooved rollers with a vertical axis 32 which slidably support, transversally to the carriage itself, a slide 33 whose end turned towards the load to be wrapped supports the upper end of an L-shaped support 34 linked to the stem of a pneumatic cylinder 35, parallel to said slide, whose body is fixed to a bracket 36 attached to carrier 1. Vertically fixed to the foot of support 34 is the body of a pneumatic cylinder 37 whose stem is downward-oriented and supports the body of a pneumatically- operated and self-centering clamp 38 whose jaws are downward- oriented. Said clamp 38 is partly protected by a special case 39 fixed to the body of the clamp and to which a vertical upward-oriented rod cooperating with a guide bar 41 fixed to said support 34 is attached so as to form a system preventing the said secondary clamp from rotating. Said secondary clamp is suitably oriented as described hereinafter, and when the apparatus is at rest it is opened, lifted and placed backward in respect of carrier 1. Finally, as shown in fig. 1 , one can see that to the side of secondary clamp P2 and farther from main clamp P1 , fixed to carrier 1 is the upper end of an L-shaped support 42 which extends downward and whose base supports the body of a pneumatic cylinder 43 wherein the stem 143 is downward-oriented and the free end is suitably rounded. Laterally articulated in 44 on the base of same support 42, on the side opposite the one turned towards the secondary clamp P2, is a preferably round-sectioned lever 45 with a rounded free end, provided with an intermediate appendage 145 articulated to the stem of a pneumatic fluid- pressured and double-action cylinder 42 fulcrum-attached to the body of carrier 1. Provided on the base of same support 42, on the side opposite the one engaged by said lever 45, is a downward-oriented nozzle 47 connected to a source (not shown) which, once operated, feeds compressed air. When the apparatus is at rest, stem 143 is lifted, as is lever 45, and nozzle 47 is inactive. At the beginning of a wrapping cycle, the film leading end unwound by reel B and fed by the pre-stretched film rolls R (fig. 5) is fixed to main clamp P1 whose arm 11 is positioned backward and lifted, and the entire apparatus is positioned farthest from the load C to be wrapped. The carriage A with reel B and the pre-stretched film rolls R turn around load C to be wrapped, underneath clamp P1 , so that the wrapping film leading end is surmounted by the first turns of the same wrapping, and once said leading end is fastened, clamp P1 opens. Once the load has been wrapped, carrier 1 , rightly phased, approaches load C so as to be at the right distance from the load itself and such condition will be, for instance, recorded by special optoelectronic sensors or electromechanical tracer points, not shown. Subsequently cylinder 43 will be activated to lower stem 143 thereof so as to have at least the final wrapping turn S1 surmount said stem 143, the length of film that touches it being at the right distance from the load and forming a pocket T adequately wider than the plan dimensions of the secondary clamp P2 assembly. As a further step of the process, carriage A of the wrapping machine will stop in a predetermined angular position in respect of the apparatus at issue and such as, after cylinder 46 has been activated to lower counter-lever 45 and said lever has taken a portion of the film tail S2 close to stem 143, the length of film between said parts 143-45 and carriage A is safely positioned on the gripping path of clamps P1 and P2 of the apparatus. Depending on the size of the load to be wrapped and it being understood that carriage A stops in an angular position at the end of the cycle, counter-lever 45 acts to align and position the film tail S2 correctly in respect of clamps P1 and P2. As next step, cylinder 13 will be activated to draw arm 11 of main clamp P1 to a vertical position, while said arm extends and said clamp opens. Following such movement, arm 11 will dispose itself laterally and at short distance from the film tail S2, underneath which the movable and open jaw 126, 28-31 of same clamp P1 will draw. Subsequently, inner sliding member 211 of arm 11 of clamp P1 will be operated and lifted and consequently the movable jaw of said clamp will lift; the secondary clamp P2 will be operated and lowered so that the film tail S2 placed between these clamps can be bundled by the jaws of same clamps, as shown in fig. 7, and transversally gripped by same clamps. At this point, the jaws of clamps P1-P2 will be operated and closed, as shown in fig. 8. Properly phased, then, counter-lever 45 goes back to the upper position, at rest. From the details of fig. 3, showing main clamp P1 , one can see that when inner sliding member 211 has been lifted, movable jaw 126 disposes itself at an end recess 100 of body 111 and when same jaw closes, the film will be gripped by it on the wall of body 111 from which blade 18 is protruding. Thanks to the "L" shape of rod 30 fitted on movable jaw 126, the film gripped by clamp P1 is taken above the guards 24 of blade 18 and the film, properly stretched, disposes itself in front of slit 19 so that, when subsequently cylinder 23 is operated and activated, the length of the film between the jaw of clamp P1 and the jaw of clamp P2 is cut by blade 18 which lifts and then lowers at rest. Rods 30 and 31 , owing to their round sections, also act to prevent the film, interfering with clamp P1 , from tearing. In this way the tail S2 of the completed wrapping will be held by clamp P2 and the film leading end coming from the wrapping machine carriage will be held by the jaw of clamp P1 whose arm 11 subsequently lifts to a horizontal position, as shown in fig. 9, while secondary clamp P2 too lifts and translates by means of cylinder 35 to approach the load and secure truing of pocket T formed in the final turn S1 by stem 143 as shown in fig. 10. Properly phased is then activated nozzle 47 which blows a descending air jet at the right pressure into pocket T, while secondary clamp P2 is lowered and inserted into said pocket T, as shown in fig. 11. After that, said clamp P2 opens and while the wrapping film tail S2 remains within pocket T because of the action exerted by the air jet, clamp P2 and stem 143, properly phased, are both lifted to the position at rest, so that, owing to the elasticity of the pre-stretched film wrapping load C, the film that formed said pocket T shrinks flat and grips the tail S2 of the wrapping itself, friction-blocking it within turn S1 , as shown in figs. 12 and 13. The guard 39 prevents secondary clamp P2 from interfering with the film while it is being inserted into and then drawn out the pocket T of the wrapping. Subsequently, clamp P2 is retracted and is taken near carrier 1 which automatically moves away from the wrapped load and returns to the position at rest useful to repeating a new wrapping cycle, as seen in the first phase of fig. 5. According to another embodiment of the invention, as shown in Figure 14, the rod 40 which avoids the rotation of the secondary clamp P2, is arranged on the side of the said clamp which is opposite to the one directed towards the load C to be wrapped and the said rod is dimensioned in its length so as to project suitably under the jaws of the said secondary clamp, the lower end of said rod being integral with the protection member 39 of the clamp P2, and being provided with rotatable and projecting rollers 48, the axis of which is substantially parallel to the carrier 1. According to a further embodiment of the invention, as illustrated in Figures 15 and 16, the stem 143 of the vertical cylinder 43 is employed for moving other means from those described with reference to Figures 1 , 11 and 12 for the formation of the pocket T in the wrapping, by eliminating the requirement of the nozzle 47. The said nozzle 47 is eliminated and to the lower end of the stem 143 there is secured in an overhanging manner a small plate 49 which is parallel to the carrier 1 and integral to the lower and rounded end of a rod 50 parallel to the said stem 143 and cooperating with a guide 53 fixed onto the base of the support 42 which carries cylinder 43. The rounded portion 150, obtained for example by bending the rod 50, is directed towards the load to be wrapped and carries, secured on the side opposite to the one directed towards the secondary clamp P2, a metallic blade 51 substantially shaped as a rectangular trapezoid, with rounded edges and corners and with the greater base directed downwards, of such a length so as to project by an ample portion beyond the rounded portion 150, in the direction of the load C, and also inclined in transverse direction and provided on its downwardly directed side with a rubber insert 52, for the reasons which will be explained hereafter. The parts described with reference to Figures 14, 15 and 16 operate in the following manner. The working cycle of the apparatus is the same as previously described in connection with Figures 8, 9 and 10, with the tail S2 of the wrapping which is held by the secondary clamp P2, with the only difference that pocket T of the said wrapping is now created by the assembly 143, 50, 150, 51 lowered in its active condition by cylinder 43, as illustrated in Figure 17. From Figures 17 and 18 it appears that the clamp P2 together with the tail S2 of the wrapping, is lifted as in the previous solution, thereafter moved over the pocket T and then lowered in the said pocket. Subsequently, as illustrated in Figure 19, the cylinder 43 lifts the assembly 50, 150, 51 , whereby the film forming the pocket bears against the rod 40 and lower roller 48 of the clamp P2 and the portion of the tail S2 which bears on the turn S1 forming the pocket T comes to be arranged below the section of the blade 51 projecting out of the curved and lower portion 150 of the assembly which previously had formed the pocket itself. Thereafter, cylinder 43 again lowers the assembly 50, 150 and 51 for such a length that the blade 51 pushes onto the portion S2' of the tail S2 which bears on the upper edge of the turn S1 so as to frictionally lock the two parts between each other, also thanks to the presence of the rubber insert 52. Subsequently, as illustrated in Figure 21 , the clamp P2 is opened and lifted out of the pocket T so as to abandon inside same the wrapping tail S2 which remains in the position in which it was abandoned, because it is held in the said position by the blade 51 and also because held almost immediately and progressively by the film forming the pocket T, which due to its elastic memory shrinks to a flat position against the load as soon as the clamp P2 has cleared out of the pocket. When the clamp P2 has been extracted, as shown in Figure 22, the cylinder 43 lifts to its rest position the assembly 143, 50, 150, 51 and the pocket T of the wrapping definitively is closed also in its upper section. The apparatus is then ready for starting a new cycle. It is understood that the double-action pneumatic cylinders employed in the apparatus described may be replaced with actuators of other types.

Claims: CLAIMS 1 ) Method for the fastening of the tail (S2) of a wrapping of plastic film for palletized loads (C) comprising the following steps: - formation of a pocket (T) in at least one of the final turns (S1 ) of the wrapping, said pocket (T) being formed by longitudinally stretching a portion of said turn and causing said stretched portion to be arranged suitably distant from the wrapped load (C); - holding the film, in the zone at which the tail (S2) of the wrapping will be formed, by means of a main clamp (P1 ) and a secondary clamp (P2); - cutting the film between the said two clamps (P1 , P2) in such a manner that the main clamp (P1 ) holds the film leading end for the wrapping cycle of a subsequent load, while the secondary clamp (P2) holds the wrapping tail of the wrapped load; - inserting the secondary clamp (P2) holding the wrapping film tail (S2) into said pocket (T); - releasing of the film tail by said secondary clamp (P2), inside the said pocket (T), and drawing said secondary clamp out of the pocket (T); - allowing the pocket (T) containing the film tail (S2) to shrink flat against the wrapped load (C), thus gripping and firmly holding the said wrapping film tail. 2) Method according to claim 1 ), in which the wrapping film in the zone between the said main clamp and the said secondary clamp is transversally restricted to form a bundle. 3) Method according to claim 1 ), in which the pocket (T) within the final wrapping film turns (S1 ) is formed by moving near to the load being wrapped suitable distancing means on which a length of the film making up the same final turns is stretched. 4) Method according to claim 1 ), in which when the wrapping film tail is inserted into the pocket (T), at least a pressure air jet is blown into such pocket, said jet acting to hold the tail in the pocket when said tail is released by the secondary clamp. 5) Method according to claim 1 ), in which after the insertion of the secondary clamp (P2) holding the film tail (S2) into the pocket (T), there is provided for the temporary holding of a portion of said film tail against the introduction edge of the pocket (T) itself, so as to avoid that the said film tail slips off the pocket after its release from the secondary clamp. 6) Apparatus for the fastening of the tail (S2) of a wrapping of plastic film for palletized loads (C), of the type comprising a main carriage (A) carrying the film, said main carriage and said load being relatively rotated between each other, characterized by the fact of comprising: - means (43, 143) which, before the final wrapping turns (S1 ) of a load are formed, are moved near the load itself so that said final turns dispose themselves transversally on them to form an open pocket (T); - means (45-46) to draw said film tail (S2) near said means (143) forming said pocket (T); - a main clamp (P1 ) and an adjacent secondary clamp (P2) to grip said tail portion (S2); - means (18) to cut the portion of film between said main clamp and said secondary clamp so that the former holds the film leading end for the wrapping cycle of a subsequent load, while the latter holds the film tail (S2) of the wrapped load; - means (32-36) to insert the secondary clamp (P2) holding the wrapping film tail (S2) within said pocket (T); - means (37-38) to open and draw the secondary clamp (P2) out of the pocket (T) and further means (43) for drawing out of the same pocket the means (143) which formed it, so that the pocket shrinks owing to the elastic features of the film and the wrapping tail is friction blocked in the final turns of the wrapping itself. 7) Apparatus according to claim 6), further comprising: - means to stop a main carriage (A) of the wrapping machine carrying the reel (B) and the pre-stretching rollers (R) at a predetermined angular position so that the length of film tail (S2) running between the said main carriage and the wrapped load is substantially tangent to said pocket; - means (45-46) to draw said film tail (S2) near said means (143) forming said pocket (T); - means (13) to move the main clamp (P1 ) to a position where it does not interfere with the movement of the main carriage; - means to blow an air jet into the pocket, oriented in the same direction of the wrapping tail insertion; - means (32-36, 1-8) to move the secondary clamp (P2) and the whole apparatus back to a rest position. 8) Apparatus according to claim 6), applied to a so called ring wrapping machine, characterized by being mounted on a carrier (1 ) oriented parallel to the handling line of the loads to be wrapped and driven on means (3-5, 3'-5') constrained to the ring structure on which the carriage (A) with the reel and the pre-stretching rollers of the wrapping machine run, said carrier (1 ) being equipped with a synchronization shaft (7) which through end pinions (6-6') co-operates with racks (5-5') fixed to the guide bars (3-3', 4-4') of the carriage one end of which is linked to alternate handling means (8). 9) Apparatus according to claim 6), wherein the means forming the pocket within the final stretchable wrapping film turns comprise a vertically placed pneumatic cylinder (43) whose body is fixed to a support (42) attached to the carrier (1 ) of the apparatus, the stem (143) of such cylinder being positioned downward, its free end being suitably rounded and having such length that, when it is extended and when the apparatus is working and near the load (C), said stem disposes itself transversally to the film run to hold a length of the final turn or turns of the wrapping so that it forms the pocket (T) into which the wrapping film tail itself (S2) will be inserted. 10) Apparatus according to claim 8), characterized by the fact that on the same support (42) bearing the cylinder (43) whose stem forms the pocket (T) there is articulated, perpendicularly to such cylinder, the end (44) of a preferably round section counter-lever (45), with a rounded free end, whose intermediate portion is linked to a pneumatic cylinder (46) whose body is fulcrum-attached to the carrier (1 ) of the apparatus and normally its stem is backward to keep said lever lifted and preferably slightly oriented upward, while when the stem of said cylinder extends, the lever (45) turns down and disposes itself parallel to the stem (143) forming the pocket (T) within the wrapping film. 11 ) Apparatus according to claim 9), characterized by the fact that to the same support (42) holding the vertical cylinder (43) whose stem forms the pocket (T) is film mounted a downward-oriented nozzle (47). 12) Apparatus according to claim 9), characterized by the fact that laterally to the cylinder (43) whose stem (143) is provided for forming the pocket (T), on the side opposite the one engaged by said counter-lever (45), there is arranged the secondary clamp (P2) comprising a guide- slide assembly (32,33) mounted on the carrier (1 ), the slide being horizontal and perpendicular to the carrier, alternately activated by a pneumatic cylinder (35) which acts to move the clamp from a position aligned to the film to a position closer to the load in order to insert the film tail into the pocket created within the wrapping, said slide bearing a support (34) for the vertical body of a pneumatic cylinder (37) whose stem is downward-oriented and which supports the operation means of a self-centering clamp 38 whose jaws are downward-oriented and which is partly surrounded by a guard (39) having the function of preventing the same clamp from interfering with the wrapping film, said guard being attached to the lower end of a vertical and ascending rod (40) which cooperates with a guide (41 ) fixed to said support (34) to prevent the guard and the clamp from rotating. 13) Apparatus according to claim 12), characterized by the fact that laterally the secondary clamp (P2), on the side opposite the means (43, 143) forming the pocket (T) within the wrapping film, there is provided the main clamp (P1 ) comprising a telescopic arm (11 ), having an end fulcrum-attached to a vertical axis (10) held by a support (9) fixed to the carrier (1 ) of the apparatus itself, said arm extending beyond said fulcrum axis through a side appendix (12) articulated to the stem of a pneumatic cylinder (13) whose body is in turn attached to a support (14) fixed to said carrier (1 ) as a projecting part, so that said clamp arm (11 ), after said cylinder has been activated, moves from a vertical, downward position to a horizontal position, said arm being equipped with an inner sliding member (211 ) whose lower end carries an appendix (16) linked to the stem of a pneumatic cylinder (17) whose body is attached to the body (111 ) of the arm, there being further provided that transversally articulated to the same lower end of said inner sliding member is the intermediate portion of a bell crank (26) which by one of its arms is placed within such inner sliding member and is linked to a pneumatic cylinder (27) attached to the same inner sliding member, while the other arm (126) of said lever protrudes from the inner sliding member itself on the side turned toward the portion of the film coming from the wrapping machine carriage (A), said lever arm forming the movable jaw of the clamp and being normally perpendicular to the same inner sliding member, there being provided that when the main clamp is at rest, the telescopic arm is in a backward position and lifted, and said jaw (126) is open, while when the clamp is operating, said telescopic arm swings downward and at the same time extends so as to arrange itself laterally to the length of the film coming form the wrapping machine carriage (A) and place the movable jaw (126) underneath such length of the film, programming means being provided for subsequently operating the lifting of the inner sliding member (211 ) of said arm (11 ) which through said jaw transversally bundles said film, it being provided that at the end of such run said jaw partly engages a recess (100) of the lower end of the body (1 1 1 ) of the arm (1 1 ), means being provided for lifting and closing the said jaw. 14) Apparatus according to claim 12), wherein the movable jaw (126) of the main clamp (P1 ) has the face in contact with the film lined with a suitable elastomeric film-frictional material (28), while fixed to the opposite face of the same clamp is a U-section case (29), carrying on its sides suitably shaped round rods (30, 31 ). 15) Apparatus according to claim 14) characterized by the fact that the inner sliding member (21 1 ) of the telescopic arm (1 1 ) of the main clamp (P1 ) is less wide than the body of said arm, it is slidably mounted within it by means of guide-slide assemblies (15) and is such as to let an inner portion of said body (1 1 1 ) turned toward the secondary clamp (P2) free for the entire height, and that on the wall of said portion of the body which is turned toward the movable jaw (126) of the main clamp there is provided a longitudinal slit (19) from which is a saw-toothed blade (18) projects, said blade being attached to an arm (1 18) which through an end carriage (22) runs along a guide (21 ) longitudinally fixed to said body (111 ) and is actuated by a pneumatic cylinder (23), provision being made that, when the apparatus is at rest, said blade (18) is surrounded by rounded guards (24) attached to the lower end of the telescopic arm body at issue, there being further provided that the rod (30) fixed to the side of the movable jaw (126) of the clamp next to said blade is L-bent at the end close to the same blade so that, when said movable jaw is closed, the film bundled by the same jaw rests on said L-end of the rod which brings it above said guards (24) of the blade which, when in operation, cuts the length of film between said rod (30) and the same movable jaw (126). 16) Apparatus according to claim 6), further comprising: - blocking means (51 , 52) for temporarily holding a portion of said film tail blocked against the introduction edge of the pocket (T). 17) Apparatus according to claim 16), in which the said blocking means comprise a vertically movable blade element (51 ), said blade element being lined with high-friction material (52) at least on its surface intended to contact the film tail. 18) Apparatus according to claim 17) in which the blocking means (51 , 52) are carried by a vertically movable rod (50) forming part of the pocket forming means (43, 143). 19) Apparatus according to claim 18), in which the secondary clamp (P2) is provided, on a side opposed to its side facing the load (C) with a rod (40) bearing against the inner side of the pocket (T) when the said secondary clamp (P2) is inserted in the said pocket, the lower end of said rod (40) projecting beyond the length greater than the length of the secondary clamp, and carrying at its free end at least one freely rotatable roller (48) intended to contact the inner side surface of the said pocket (T).

Inventors: BUSCHERINI ROBERTO, FANTINI DAVIDE, BUSCHERINI, ROBERTO, FANTINI, DAVIDE
Applicants: BUSCHERINI ROBERTO, FANTINI DAVIDE, PIERI SRL, BUSCHERINI, ROBERTO, FANTINI, DAVIDE, PIERI S.R.L.
Application year: 1998
Main classification: B65B11
IPC codes: B65B11