WRAPPING APPARATUS

Abstract: Wrapping apparatus for winding stretch film (16) or the like round goods on a pallet. Distinguishing for the invention is a horizontal, rotatable plate (2) on which the goods is intended to be placed, a vertical pillar (4) arranged at one side of the plate, two carriages (7, 8) each provided with a retaining rod for its respective storage reel (15) of the stretch band, said carriages being arranged movable along the pillar. A sheave (5) is provided in the top portion of the pillar and a line (6) with one end fixed to one carriage and the other end to the other carriage passes over the sheave such as to suspend the two carriages with their storage reels in a substantially balanced state.

Description: WRAPPING APPARATUS 1 Introduction The present invention relates to a wrapping apparatus for winding a band, e.g. of paper, netting, stretch plastic-film, etc. as wrapping round goods. Background Art Wrapping apparatus is already known for applying a hose of shrink film over goods resting on a pallet. The hose is supplied flat and wound on a reel. These known wrapping apparatus must have means for opening the hose before it is drawn over the goods. Such apparatus has a complicated con¬ struction and is therefore expensive. This results in that such apparatus is not used in small and medium-sized manufac¬ turing companies producing goods which are loaded onto pallets before transporting away from the factory. Disclosure of Invention An object of the present invention is to provide a wrapping apparatus of the kind indicated above, which has few components and is therefore both simple and cheap to manufacture. The characterizing features of the invention are disclosed in the accompanying claims. The invention has the advantage that after attaching the band, serving as wrapping at the lower portion of the goods rotation of a horizontal plate on which the pallet with the goods rests will result in that the goods is rotated, thus pulling off the band from one of the band storage reels. Movement upwards of a carriage, on which this supply reel is provided along a pillar simultaneously with said rotation of the goods, results in wrapping the goods. When this carriage moves upwards, a second carriage provided with a second band storage reel moves downwards along the pillar and serves as a counterweight for the carriage which moves upwards. The second carriage will finally arrive at the starting position in which the band of the second band storage reel now is attached at the lower portion of new goods positioned for wrapping, on said horizontal plate, after removal of the now wrapped first goods from the horizontal, rotatable plate. Since the two carriages are substantially mutually counter¬ balanced, very small force is required for manually moving vertically upwards along the pillar the carriage carrying the reel from which the band is pulled off. The operator handling the wrapping apparatus can therefore manage it with small effort. Other advantages of the invention will be understood from the following imaginary example: Assume that one carriage with its supply reel is removed and exchanged for a counterweight the weight of which corresponds to the weight of the remaining carriage and its band supply reel. By degrees, as the band is pulled off from the reel in the course of wrapping goods, the weight of the carriage and its reel will decrease, in turn signifying that the counter-weight, the weight of which is constant, tends to move the carriage and reel upwards along the pillar. This is, of course, to advantage for winding the band round the goods, but after goods have been wrapped the. operator must push the carriage down along the pillar, while overcoming the difference in weight between counterweight and carriage with its reel, and down to the starting position. This will require more and more effort the less amount of band remains on the reel. A storage reel normally weights about 15 kg to start with, which will thus be the weight which must be finally overcome when the carriage is to be pushed down to the starting position. If the counterweight in the above imaginary example, now is exchanged for a carriage provided with a band supply reel, the following occurs. After goods have been wrapped with band from one band storage reel, the band is cut and the wrapped goods removed from the rotating plate. This first reel is now lighter than the second reel, resulting in that the second carriage on which the second reel is mounted will slide down the pillar due to the difference in weight. The carriage slides right down to the starting position during the time new goods is placed on the horizontal, rotatable plate. The band from the second reel is attached to the goods which is then wrapped. After wrapping, the second band is cut, at the top portion of the goods, and the difference in weight between the two carriages with their reels will be at a minimum the whole time, since the band is removed alternatingly from the two reels. An additional advantage with using two carriages, and thus two reels, is that band reel replacement only needs to take place half as often as compared with the case where only one reel and a counterweight are used. The invention will be described in detail below in connection with the accompanying drawings, wherein Figure 1 is a perspective view of the wrapping apparatus, Figure 2 is a top view of the wrapping apparatus, and Figure 3 is a cross sectional view of a stretching device included in the wrapping apparatus in accordance with the invention. The wrapping apparatus in accordance with the present invention is illustrated in Figure 1. A horizontal plate 2 is mounted for rotation on a bearing, not shown, provided on a stand 1. An electric motor 3 rotates the plate 2 by belt drive system, not shown, arranged inside the stand 1. The plate 1 rotates at a comparatively low speed, and is intended to carry goods which are placed on a pallet and which are to be wrapped with stretch film, which is wound around the goods on the pallet in a stretched state and subsequently is cut off. The stretch film then tends to shrink to its original length and will conse- quently stabilise the goods on the pallet. A vertical pillar 4 is attached to the stand and has upwardly a sheave 5 over which a line 6 is taken. One end of the line is fastened to a first carriage 7 and the other end to a second carriage 8. The carriages are movable along the pillar. It will be under¬ stood that when one carriage moves upwards the other moves downwards and vice versa. Each carriage includes four wheels, of which, two wheels 9, 10 of the first carriage 7 are il¬ lustrated in Figure 1. The two carriages 7, 8 are made the same and therefore only one carriage is described, in this case the second carriage 8. It will be seen from Figures 2 and 3 that the carriage 8 is provided with a vertical carrying plate 36, which at its lower end portion is provided with a horizontal projecting bottom plate 37. The lower end portion of a vertical rod 38 is fixed to the bottom plate 37. A storage reel 15 is thrust over the rod 38 from above to assume the position illustrated in Figure 1. The carriage also includes a film tensioning or stretching device 17 including two rolls 18, 19, rotatably mounted between two mounting plates 20, 21 (see Figure 1). The stretch film passes between the rolls 18, 19 such that it is in contact with a part of the peripheral surface on each roll. The stretching device 17 is pivotably mounted on the carriage with the aid of a smooth rod 22 extending between two support plates 23, 24 fixed respectively upwardly and downwardly to the carrying plate 36. The two carriages with their stretching devices and storage reels are identically implemented and thus weight equally as much. Both carriages are suspended in the line and the whole system is balanced out in the starting position. An operating cabinet 25, illustrated in Figure 1, is attached to the stand 1 and contains start and stop buttons for the motor 13 as well as conventional electronic equipment for phase control of the motor speed using a potentiometer, not shown, which is also placed at the operating cabinet. It will be seen from Figure 2 that the pillar 4 is formed from two large I-beams 30, 31 welded to each other as shown in the Figure. Four longitudinal flanges 32, 33, 34, 35 are thus formed and serve as rails for the respective carriage 7, 8. The stretching device for the first carriage will not be described further since it is identical with the stretching device 17 for the second carriage 8, which will now be des¬ cribed below in connection with Figure 3. At the bottom end of the roll 18 there is provided a first gear wheel 40 and at the bottom end of the roll 19 there is provided a second gear wheel 42. A third gear wheel is non-rotatably mounted on the lower part of the smooth rod 22 and this third gear wheel is in mesh with the first gear wheel 41. A fourth gear wheel 43, which is rotatably mounted on a journalling pin 44 passing through the lower plate 21, is in mesh with the third gear wheel as well as with the second gear wheel 42. The stretch film 16 from the supply reel 15 passes between the rolls 18, 19 in the way illustrated in the Figure and in the direction denoted by the arrow 45. The four gear wheels form together a gearing having a gear ratio which is so arranged that the roll 19 rotates at a greater speed than the roll 18, and in the preferred embodiment with a speed which is 40% higher than that for the roll 18. Beginning with the starting position in Figure 1, stretch film is pulled towards the lower portion of the goods, not shown, on the plate 2, and is attached to the goods. The start button is then depressed so that the plate 2 begins to rotate and pull the film from the supply reel 15. It will be under¬ stood that the film is stretched as it is pulled from the reel by the goods rotated by the plate. In addition, the film is stretched due to the stretching device. More specifical¬ ly, the part of the film between the rolls 18, 19 is subjected to such stretching. The film thus stretched in two ways is taken two turns, for example, round the bottommost part of the goods, after which the operator moves the second carriage 8 upwards with the aid of a handle 26 illustrated in Figures 2 and 3. The operator moves the second carriage upwards at a speed such that each turn of the stretch film is overlapping a preceeding turn with about half the width of the film. At the uppermost part of the goods the operator stops the upward movement of the carriage and the plate is allowed to rotate a further two revolutions so that the stretch film is taken two turns round the goods here as well. The plate is then stopped and the film is cut. Wrapping the first lot of goods is now finished. During this wrapping procedure, when the operator moves the second carriage upwards the first carriage moves downwards so that it is finally in its bottommost position. Since no film is reeled from the first storage reel on the first carriage during this downward movement, the first reel and carriage will only weight slightly more than the second reel and carriage. The whole system is substantially balanced out and ready for wrapping a new lot of goods, this time using the film pulled from the storage reel on the first carriage. When the second lot of goods has been wrapped completely, by once again starting the motor and moving the first carriage upwards, cutting off the film and removing the second lot of goods, the operator is once again in the position illustrated in Figure 1. In this way, film will be pulled in turn from the second reel, the first reel, the second reel and so on. The system will thus be substantially balanced out the whole time until all film has been pulled off from both reels. When it is time for changing reels, the carriages are taken to the same height and an unillustrated pin is thrust into an unil- lustrated through hole in the pillar 6 so that the bottom plates 37 of the carriages rest against this pin. The old reels are then removed and new storage reels placed on each carriage in this position. The phase control of the motor and thereby the rotational speed of the plate 2 is so controlled by the potentiometer, not shown, that the plate starts slowly and successively increases speed until a predetermined speed is reached. When the film is subjected to the stretching in the respective stretching device, there is a risk that the width of the film contracts, which should be prevented as far as possible. For this reason the rolls 18 and 19 are provided with helically wound tapes 51, 52, 53, 54 on their cylindrical surfaces. These tapes are made from friction material and are glued to the surfaces of the rolls. As will be seen from Figure 1 the tape 51 is spirally wound along half the length of the roll 18 with a spiral in one direction while the tape 52 is wound round the other half of the same roll but with the opposite spiral direction. The same thing applies to the other roll 19. In this way, when the rolls 18 and 19 are rotated by the film, the tapes tend to stretch the film from its centre and outwards to the film edges. The described embodiment can be modified in many different ways and varied within the scope of the accompanying claims.

Claims: CLAIMS 1. Apparatus for winding a band e.g. of plastic film, paper, netting etc as wrapping round goods characterized by: a stand (1) with a horizontal, rotatably mounted plate (2) on which the goods are intended to be placed, a vertical pillar (4) arranged on the stand to one side of the plate, two carriages (7, 8) each provided with a rod (38) serving as a retainer for a storage reel (15) of the band, eacsh being movably arranged along the pillar directly opposite the other, a sheave (5) arranged at the upper portion of the pillar, -.and a line (6) one end of which is attached to one carriage and the other end to the other carriage, said line passing over the sheave to suspend the two carriages in a substantially balanced-out state. 2. Apparatus as claimed in claim 1, characterized in that each carriage (7, 8) has a handle (26) for manually moving the carriage upwards along the pillar. 3. Apparatus as claimed in claim 2, characterized by an electric motor (3) and a belt and pulley drive system for rotating the plate (2). 4. Apparatus as claimed in one ore more of the preceding claims, -the band being a plastic film (16) characterized in that a tensioning device (17) is disposed on each carriage for stretching the film supplementary to the stretching taking place as a result of the rotating goods pulling off the film from said one storage reel (15). 5. Apparatus as claimed in one or more of the preceding claims characterized in that a tensioning device (17) includes two rolls (18 r 19) mounted mutually parallel between two bearing plates (20, 21), the film being taken between the rolls so that it is in contact with a part of the cylindrical surface of each roll (18, 19) and spur gearing (40-43) synch¬ ronising the rotation of the rolls to each other with a gear ratio selected such that when one roll (18) rotates at a first speed the second roll (19) rotates at a second speed which is greater than the first one, whereby the part of the film between the rolls is stretched. 6. Apparatus as claimed in claim 5, characterized in that the roll (18) which, seen in the pulling-off direction of the film, first meets the film and is thus put into rotation, rotates at the first speed while the second roll (19) which is downstream of the first roll rotates with the second, higher speed. 7. Apparatus as claimed in claim 6, characterized in that the gearing has at least three gear wheels (40, 41, 42, 43) one being rigidly attached to one roll, the second being rigidly attached to the second roll and the remaining between the first and second gear wheels and in mesh with these and with each other. 8. Apparatus as claimed in claim 7, characterized by a first tape (51) which with a first spiral direction is wound round the circumference of each roll (18, 19) along half the length of the roll, and a second tape (52) which is spirally wound in the opposite direction to the first tape round the circumference of the remainder of the length of the roll to prevent reduction in width of the stretch film when the film is stretched between the rolls. 9. Apparatus as claimed in claim 7, characterized by a smooth rod (22) extending between the bearing plates (20, 21) to thrust out a distance from each of these to serve as journall- ing pins for mounting the tensioning device in support plates (23, 24) on the carriage.

Inventors: BILLBERG ANDERS, BILLBERG, ANDERS
Applicants: BILLBERG A AB, A. BILLBERG AB
Application year: 1990
Main classification: B65B11
IPC codes: B65B11