Abstract
A device for banding products includes a supply mechanism for supplying band material from a supply roll, a strap chute for forming a loop in an end portion of the band material around a space for accommodating products, and a cutter for cutting off the end portion and means for closing the loop. The supply mechanism includes conveyors for gripping the band material over part of its length and conveying the same in a guided manner, as well as a motor for driving the conveying means.
Claims
1. A device for banding products, comprising: a supply mechanism for supplying band material from a supply roll, means for forming a loop in an end portion of the band material around a space for accommodating products, and a cutter for cutting off the end portion and a sealer for closing the loop, wherein the supply mechanism comprises conveying means for gripping the band material over part of its length and conveying the same in a guided manner, as well as driving means for driving the conveying means; wherein the conveying means comprise at least two assemblies, which each of said at least two assemblies comprise pulleys and at least one endless conveyor belt to be passed thereover; wherein the at least two assemblies comprise a first assembly and a second assembly, and a length portion of a side of the conveyor belt of the first assembly that faces away from the pulleys is in contact with a length portion of a side of the conveyor belt of the second assembly that faces away from the pulleys via band material to be guided therebetween; wherein the length portions are in contact with each other at a location of one of said pulleys, such that a curvature of the pulley defines a curved contact surface between the length portions of the conveyor belts; and wherein one of the pulleys is driven.
2. The device according to claim 1, wherein the conveyor belts move forward at a same angular speed at the location of the contact therebetween.
3. The device according to claim 1, wherein at least part of a surface of the conveyor belt that faces away from the pulley is rough.
4. The device according to claim 1, wherein at least part of an outer surface of at least one pulley of at least one assembly of the conveying means is rough; and wherein at least part of a surface that faces the pulleys, of the conveyor belt of said at least one assembly of the conveying means, is rough.
5. The device according to claim 1, wherein the pulleys are externally toothed, and wherein the conveyor belts comprise toothed endless belts for engaging the pulleys.
6. The device according to claim 1, wherein the conveyor belts are made of an elastic material.
7. The device according to claim 1, wherein at least one of said pulleys of each said assembly is driven.
8. The device according to claim 1, wherein axes of rotation of said pulleys extend parallel to each other.
9. The device according to claim 1, wherein circular centre planes of said pulleys lie in a same flat plane.
10. The device according to claim 1, wherein at least part of an outer surface of at least one pulley of at least one assembly of the conveying means is rough; or wherein a surface that faces the pulleys, of the conveyor belt of said at least one assembly of the conveying means, is rough.
11. The device according to claim 5, wherein the toothed endless belts are toothed on one side.
12. The device according to claim 6, wherein the elastic material is rubber.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention will now be explained in more detail with reference to figures illustrated in a drawing, in which:
(2) FIG. 1 is a perspective view of a banding machine in a preferred embodiment of the invention;
(3) FIG. 2 is a cross-sectional view of a part of the banding machine of FIG. 1;
(4) FIG. 3 is a perspective view of a first supply mechanism in the banding machine of FIG. 1; and
(5) FIG. 4 is a perspective view of a second supply mechanism in the banding machine of FIG. 1.
DETAILED DESCRIPTION
(6) FIG. 1 shows a perspective view of a banding machine 100. Such a banding machine carries band material 101 from a supply roll 102 through the machine to wrapping means 103. In its path to the wrapping means 103, the band material 101 is successively carried through a first supply mechanism 104, passed over a set of conveyor ropes 105 and carried to the wrapping means 103 via a second supply mechanism 106. The wrapping means 103 subsequently form a loop of band material 101 about a product 107 to be banded. Finally, the loop of band material 101 is closed under the product 107, for example using an adhesive bond, and the closed loop is cut loose from the upstream band material 101 by cutting means. It is noted that in the illustrated embodiment the second supply mechanism 106 is capable of conveying the band material 101 in two opposite directions, so that the band material 101 can be retracted for tightening the loop of band material 101 around the product 107 to be banded before closing of the loop takes place.
(7) FIG. 2 shows a cross-sectional view of a part of the banding machine 100, in which the path of the band material 101 through the first supply mechanism 104 and over the set of conveyor ropes 105 toward the second supply mechanism is shown. FIG. 2 further shows parts of the first supply mechanism 104, consisting of an electric motor 108, gears 109, 110 and 111, tension pulleys 112, 113, 114 and 115 and conveyor belts 116, 117 and 118. The manner in which these parts cooperate will be explained in more detail with reference to FIG. 3. FIG. 2 also shows that the set of conveyor ropes 105 consists of two main sets of conveyor ropes 1051 and 1052, which are each driven by separate electric motors via driven pulleys 119 and 120. The main set 1051 comprises 4 sets of conveyor ropes 1051a, 1051b, 1051c and 1051d. The main set 1052 in turn comprises 7 sets of conveyor ropes 1052a, 1052b, 1052c, 1052d, 1052e, 1052f and 1052g. In this way the two main sets 1051 and 1052 form a buffer mechanism 201, which conveys each of the legs 101a and 101b of a free loop of the band material 101 at an individual speed. As a result, the speed at which band material 101 is unwound from the supply roll 102 is unlinked from the speed at which band material 101 is arranged around a product 107 by the wrapping means 103. At the same time, the conveyor ropes 1052 of the second set are movable in two opposite directions, so that the band material 101 can be retracted in cooperation with the second supply mechanism 106 for being stretched around the product 107.
(8) FIG. 3 shows a perspective view of a front side 104a of the first supply mechanism 104. During use of the banding machine 100, the band material 101 coming from the supply roll 102 is conveyed in conveying directions 121a and 121b as indicated by arrows from an entry side 104c, through the first supply mechanism 104, to an exit side 104d. Referring to FIGS. 1 a 2, the supply roll 102 is therefore located at the entry side 104c, and the set of conveyor ropes 105 is located at the exit side 104d. The transport takes place as follows: an electric motor 108 drives an externally toothed gear 109, causing the gear 109 to rotate about its axis of rotation. The gear 109 is connected to a (likewise externally toothed) gear 110 via a toothed (on one side) endless conveyor belt 116. The gear 110 subsequently causes the gear 111 to rotate about its axis of rotation via a second toothed (on one side) endless conveyor belt 117 that passes over the gears 110 and 111, being tensioned by tension pulleys 112 and 113. Viewed in relation to the axis of rotation of the gear 111, tension pulleys 114 and 115 are present on either side of the toothed edge of the gear 111. A conveyor belt 118 passes over said tension pulleys 114 and 115, wherein the central axis of the conveyor belt 118, which points in the direction of movement of the conveyor belt 118, extends substantially parallel to that of the conveyor belt 117, being located at substantially the same height z as that of the conveyor belt 117. Because the tension pulleys 114 and 115 are located on either side of the edge of the gear 111, and the conveyor belts 117 and 118 are oriented in this manner relative to each other, the conveyor belts 117 and 118 are in contact with each other over part of their lengths via the band material 101 to be conveyed therebetween, defining a curved contact surface 122 between their length portions at the location of the gear 111. As a result, the band material 101 is gripped over the area of the curved contact surface 122. This has the advantage that the conveying directions 121a and 121b of the band material 101 upstream of the gripping area and the band material 101 downstream of the gripping area are in line with each other. This makes it possible not only to convey the band material quickly without any undesirable running off effects, but also to control the amount of band material that is to be conveyed with a high degree of precision. In the illustrated embodiment, the gear 111, like the gears 109 and 110, is circular in shape, so that the curvature of the curved contact surface 122 will follow the circumference of a part of the circle. By realising sufficient friction between the band material 101 and the conveyor belts 117 and 118, the conveyor belts 117 and 118 will move forward at the same angular speed at the location of the curved contact surface 122, so that effects such as running off, sloughing and the like that frequently occur in current banding machines, are prevented. It is noted that the tension pulleys 112, 113, 114 and 115 all perform their tensioning function on the conveyor belts 117 and 118 by means of spring mechanisms provided at the rear side 104b of the first supply mechanism 104.
(9) FIG. 4 shows a perspective view of the second supply mechanism 106. This second supply mechanism 106 mainly consists of an electric motor 124 and two externally toothed gears provided directly on the electric motor 124, one gear 125a of which is located at the front side 106a of the second supply mechanism 106 and the other gear (not shown) of which is provided on the electric motor 124 at the rear side 106b of the second supply mechanism 106. The gears 125a (and another not shown) drive two assemblies of gears, tension pulleys and conveyor belts via conveyor belts 126a (and another not shown), respectively, the first assembly consisting of a gear 127, five tension pulleys 128, 129, 130, 131 and 132 and a conveyor belt 133, and the second assembly consisting of a gear 134, three tension pulleys 135, 136 and 137 and a conveyor belt 138. During use of the banding machine 100, the band material 101 coming from the set of conveyor ropes 105 is conveyed in conveying directions 123a and 123b as indicated by arrows from an entry side 106c, through the second supply mechanism 106, to an exit side 106d. Referring to FIGS. 1 a 2, the set of conveyor ropes 105 is located at the entry side 106c, and the wrapping means 103 are located at the exit side 106d. The transport of band material 101 takes place as follows: the electric motor 108 drives an externally toothed gear 125a, causing the gear 125a to rotate about its axis of rotation during operation. The gear 125a is connected to a (likewise externally toothed) gear 127 via a toothed (on one side) endless conveyor belt 126a, as a result of which the gear 127 rotates about its axis of rotation during operation. The gear 127 subsequently causes the conveyor belt 133 to move forward over the tension pulleys 128, 129, 130, 131 and 132. The gear (not shown) at the rear side 106b of the second supply mechanism 106 is connected with a (likewise externally toothed) gear 134 by means of the toothed (on one side) endless conveyor belt (not shown), so that the gear 134 will rotate about its axis of rotation during operation. The gear 134 subsequently causes the conveyor belt 138 to move forward over tension pulleys 135, 136 and 137. The central axis of the conveyor belt 133, which points in the direction of movement of the conveyor belt 33, extends substantially parallel to that of the conveyor belt 138, being located at substantially the same height z as that of the conveyor belt 138. Because the tension pulleys 135 and 136 are located on either side of the edge of the gear 127, and the conveyor belts 133 and 138 are oriented in this manner relative to each other, the conveyor belts 133 and 138 are in contact with each other over part of their lengths via the band material 101 to be conveyed therebetween, defining a curved contact surface 139 between their length portions at the location of the gear 127. As a result, the band material 101 is gripped over the area of the curved contact surface 139. This has the advantage that the conveying directions 123a and 123b of the band material 101 upstream of the gripping area and the band material 101 downstream of the gripping area are in line with each other. This makes it possible not only to convey the band material quickly without any undesirable running off effects, but also to control the amount of band material that is to be conveyed with a high degree of precision. This enhances on the one hand the banding capacity and on the other hand the precision with which a certain amount of band material can be retracted, resulting in a high precision over a large force area with which the band material can be stretched around the product. In the illustrated embodiment, the gear 127 is circular in shape, so that the curvature of the curved contact surface 139 will follow the circumference of a part of the circle. By realising sufficient friction between the band material 101 and the conveyor belts 133 and 138, the conveyor belts 133 and 138 will move forward at the same angular speed at the location of the curved contact surface 139, so that effects such as running off, sloughing and the like that frequently occur in current banding machines, are prevented. FIG. 4 further shows that the tension pulleys 130 and 136 performed their tensioning function on the conveyor belts 133 and 138 by means of spring mechanisms provided either at the front side 106a or at the rear side 106b of the second supply mechanism 106.
(10) The invention is not limited to the embodiment shown herein, but it also extends to other preferred variants that fall within the scope of the appended claims.
