APPARATUS FOR BANDING PRODUCTS

Abstract

A device for banding products includes a supply mechanism for supplying band material from a supply roll at an unwinding speed, wrapping means for forming a loop in an end portion of the band material around a space for accommodating products at a banding speed, means for cutting off the end portion and means for closing the loop. A buffer mechanism is disposed between the supply mechanism and the wrapping means, and includes at least a first and a second assembly of conveying means for conveying the band material from the supply mechanism to the wrapping means at a conveying speed and driving means for driving the conveying means. The first and the second assembly of conveying means are driven independently of each other.

Claims

1. A device for banding products, comprising: a supply mechanism for supplying band material from a supply roll at an unwinding speed, wrapping means for forming a loop in an end portion of the band material around a space for accommodating products at a banding speed, means for cutting off the end portion and means for closing the loop, and a buffer mechanism between the supply mechanism and the wrapping means, comprising at least a first and a second assembly of conveying means for conveying the band material from the supply mechanism to the wrapping means at a conveying speed and driving means for driving the conveying means, wherein the first and the second assembly of conveying means are driven independently of each other.

2. A device according to claim 1, wherein the conveying speed of the first assembly of conveying means substantially corresponds to the unwinding speed, and wherein the conveying speed of the second assembly of conveying means substantially corresponds to the banding speed.

3. A device according to claim 1, wherein at least one assembly of conveying means is movable in two opposite conveying directions.

4. A device according to claim 1, wherein each of said first and the second assembly of conveying means comprises pulleys and at least one conveyor belt to be passed thereover.

5. A device according to claim 4, wherein a free loop of band material is formed in the buffer mechanism, and wherein a same contact side of the band material is in contact with the conveyor belt of the first assembly of conveying means and the conveyor belt of the second assembly of conveying means.

6. A device according to claim 4, wherein the conveyor belt of the first assembly of conveying means extends substantially parallel to the conveyor belt of the second assembly of conveying means,

7. A device according to claim 4, wherein at least part of a surface of the conveyor belt that faces away from the pulleys is rough.

8. A device according to claim 4, wherein at least part of an outer surface of at least one pulley of at least one assembly of 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 conveying means, is rough.

9. A device according to claim 4, wherein the pulleys are externally toothed, and wherein the conveyor belts comprise toothed endless belts for engaging the pulleys.

10. A device according to claim 4, wherein the conveyor belts are at least partially permeable to gas, and wherein the device further comprises at least one of blowing and suction means for generating a difference in gas pressure between a side of the band material that faces the conveyor belt and a side thereof that faces away from the conveyor belt.

11. A device according to claim 10, wherein the at least one of said blowing and suction means are configured to generate a partial vacuum in use.

12. A device according to claim 10, wherein the device comprises an at least partially gas-permeable cover plate on at least one side of said at least one blowing means and said suction means.

13. A device according to claim 12, wherein the cover plate is configured so that said at least one blowing means and said suction means realise high and low pressure zones in a vicinity of the buffer mechanism, such that a gas pressure difference is substantially homogeneously distributed along a length of the band material and is sufficiently high to connect the band material to the conveyor belts during a building up of a buffer of said band material and is sufficiently low to disconnect the band material from the conveyor belts during a reducing of the buffer of said band material.

14. A device according to claim 4, wherein at least one pulley of each said assembly of conveying means is driven.

15. A device according to claim 4, wherein axes of rotation of said pulleys extend substantially parallel to each other.

16. A device according to claim 4, wherein circular centre planes of said pulleys lie substantially in a same flat plane.

17. A device according to claim 4, wherein at least part of an outer surface of at least one pulley of at least one assembly of conveying means is rough; or wherein at least part of a surface that faces the pulley, of the conveyor belt of said at least one assembly of conveying means, is rough.

18. A device according to claim 9, wherein the toothed endless belts are toothed on one side.

19. A device according to claim 12, wherein the at least partially gas-permeable cover plate is disposed on a side of said at least one blowing means and said suction means that is opposite said at least one blowing means and said suction means.

Description

[0018] The invention will now be explained in more detail with reference to figures illustrated in a drawing, in which:

[0019] FIG. 1 is a perspective view of a banding machine according to a preferred embodiment of the invention;

[0020] FIG. 2 is a cross-sectional view of a part of the banding machine of FIG. 1;

[0021] FIG. 3 is a cross-sectional view of the buffer mechanism in the banding machine of FIG. 1; and

[0022] FIG. 4 is a perspective, cross-sectional view of the buffer mechanism in the banding machine of FIG. 1.

[0023] 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.

[0024] 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 106 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. Finally, FIG. 2 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. The cooperation between the parts of the buffer mechanism 201 will be explained in more detail with reference to FIG. 3.

[0025] FIG. 3 shows a cross-sectional view of the buffer mechanism 201. The buffer mechanism 201 consists of two pulleys 119 and 120 driven by separate electric motors (not shown), which pulleys are capable of rotating the pulleys 119a, 119b, 119c, 119d and the pulleys 120a, 120b, 120c, 120d, 120e, 120f, 120g via sets of conveyor ropes 1051a-d and 1052a-g, respectively. The main set of conveyor ropes 1051 is thus driven separately from the set of conveyor ropes 1052. By causing the driven pulley 119 to rotate clockwise, a buffer of band material 101 from the supply roll 102, shown as a free loop of band material with legs 101a and 101b in FIG. 3, can be built up by the buffer mechanism 201. By causing the driven pulley 120 to rotate clockwise, the buffer of band material 101, shown as a free loop of band material with legs 101a and 101b in FIG. 3, can be reduced by a buffer mechanism 201. The unwinding of the band material 101 from the supply roll 102 is thus unlinked from the wrapping of the band material 101 around the product 107. Because the two sets of conveyor ropes 1051 and 1052 are driven separately from each other, the speed at which band material 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. Uneven loading of the band material during the wrapping process can therefore be prevented and the banding speed can be increased, resulting in a higher banding capacity. Finally it should be noted that the driven pulley 120 is driven by an electric motor which also drives the second supply mechanism 6. The second main set of conveyor ropes 1052 is therefore 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.

[0026] FIG. 4 shows a perspective cross-sectional view of the buffer mechanism. The figure shows driven pulleys 119 and 120 and a toothed belt 120a, which connects the pulley 120 to an electric motor (not shown) of the second supply mechanism 106. FIG. 4 also shows pulleys 119d and 120d, 120e and 120f and cross-sectional views of the sets of conveyor ropes 1051a, 1051d, 1052a, 1052e, 1052f and 1052g, consisting of 4 or 5 substantially parallel conveyor ropes which are each passed over two pulleys. In the illustrated embodiment, the pulleys are provided on the outer side of the walls of a housing 121. In the illustrated embodiment, the space between the individual conveyor ropes of each set allows air or another gas to flow between the conveyor ropes. In combination with blowing and/or suction means 122 and holes 123, 124, 125, 126 and 127 in the side walls of the housing 121, which allow air to pass therethrough, a difference in air pressure can be generated between the side 128 of the band material 101 that faces the conveyor ropes and the side 129 thereof that faces away from the conveyor ropes. As a result, the band material 101 is connected to sets of conveyor ropes, which increases the precision of guiding during transport, resulting in an increased banding capacity.

[0027] The device may also comprise an at least partially air-permeable cover plate (not shown) on at least one side, preferably on a side opposite the blowing and/or suction means. Such a cover plate will in that case preferably be configured so that the blowing and/or suction means realise substantially homogeneously distributed high and low pressure zones in the vicinity of the buffer mechanism. This makes it possible to realise the difference in air pressure between the two sides of the band material to be conveyed such that the difference in air pressure will be distributed substantially homogeneously along the length of the band material and that said difference in air pressure will be sufficiently high for connecting the band material to the conveyor belts during the building up of a buffer and sufficiently low for disconnecting the band material during the reducing of the buffer, i.e. during the wrapping process.

[0028] 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.