Device for splitting foam bodies

Abstract

A thin layer is cut from a foam material body using a band-knife. A take-off device that lifts and removes the layer from the cutting site, includes a belt conveyor with an electrostatically chargeable conveyor element. The layer is lifted and removed from the cutting site by electrostatic attraction to the conveyor element.

Claims

1. A method for splitting a foam material body with a circulating band-knife, comprising: moving the foam material body with respect to the band-knife so as to split off a layer, and wherein the split-off layer is continuously removed away from the band knife at an angular range larger than 90 degrees immediately after having been split off from the foam material body, wherein a direction of separation is in a forward direction less than 90 degrees from an uncut portion of the foam material body and greater than 90 degrees from a cut portion of the foam material body, wherein the layer is subsequently lifted and removed from the material body by electrostatic attraction to a conveyor element oriented obliquely to a surface of the foam material body, wherein a portion of the conveyor element is positioned almost tangentially to the surface of the foam material body, wherein the foam material is grounded through contact with the knife or a knife guide guiding the knife and electrostatically neutral; and wherein the conveyor element has a lower distal end positioned substantially above a cutting tip of the circulating band knife, the lower distal end of the conveyor element positioned so that at least a portion of the lower distal end is disposed past the cutting tip of the circulating band knife in a tip direction.

2. The method of claim 1, wherein the lifting and removal of the layer is affected by the conveyor element in a continuous manner and with a constant pulling force.

3. A device for splitting foam material bodies, comprising an endless band-knife which has a cutting edge for splitting off a layer from the foam material body, and further comprising a take-off device for removing the layer from the foam material body, wherein the take-off device comprises an electrostatically chargeable conveyor element oriented obliquely to a surface of the foam material body that removes the split-off layer from the foam material body in an upward direction at the cutting position where the cutting edge engages, wherein the layer is subsequently lifted and removed from the material body in a forward direction away from the endless band knife at an angular range larger than 90 degrees, said forward direction being less than 90 degrees from an uncut portion of the foam material body and greater than 90 degrees from a cut portion of the foam material body, wherein a portion of the chargeable conveyor element is positioned almost tangentially to the surface of the foam material body, and wherein the foam material is grounded through contact with the knife or a knife guide guiding the knife and electrostatically neutral; and wherein the electrostatically chargeable conveyor element has a lower distal end positioned substantially above a cutting tip of the endless band knife, the lower distal end of the electrostatically chargeable conveyor element positioned so that at least a portion of the lower distal end is disposed past the cutting tip of the endless band knife in a tip direction.

4. The device of claim 3, wherein the conveyor element is a flexible endless band circulating around guide rolls, a first guide roll being arranged at the cutting position where the cutting edge of the band-knife engages the foam material body.

5. The device of claim 3, wherein the take-off device is a belt conveyor with an upper strand for transporting away the split-off layer.

6. The device of claim 3, wherein the take-off device is a belt conveyor with a lower strand for transporting away the split-off layer.

7. The device of one of claim 3, wherein the conveyor element is a band made from an electrically non-conductive material, and that an electrostatic charging device is arranged stationary along the path of the band.

8. The device of claim 7, wherein the charging device comprises an electric ionization device.

9. The device of one of claim 3, wherein the movement of the conveyor element is synchronized with the speed of the foam material body, such that an adjustable difference in speed is not greater than 20 percent.

10. A device for splitting foam material bodies, comprising an endless band-knife which has a cutting edge for splitting off a layer from the foam material body, and further comprising a take-off device for removing the layer from the foam material body, wherein the take-off device comprises an electrostatically chargeable conveyor element oriented obliquely to a surface of the foam material body that removes the split-off layer from the foam material body in an upward direction at the cutting position where the cutting edge engages, wherein the layer is subsequently lifted and removed from the material body in a forward direction away from the endless band knife at an angular range smaller than 90 degrees, wherein a portion of the chargeable conveyor element is positioned almost tangentially to the surface of the foam material body, wherein the chargeable conveyor element is a belt conveyor comprising a lower strand, the lower strand transports away the layer, and wherein the foam material is grounded through contact with the knife or a knife guide guiding the knife and electrostatically neutral; and wherein the electrostatically chargeable conveyor element has a lower distal end positioned substantially above a cutting tip of the endless band knife, the lower distal end of the electrostatically chargeable conveyor element positioned so that at least a portion of the lower distal end is disposed past the cutting tip of the endless band knife in a tip direction.

Description

(1) The following is a detailed description of embodiments with reference to the accompanying drawing.

(2) In the Figures:

(3) FIG. 1 is a schematic side elevational view of a first embodiment of a device for splitting foam material bodies,

(4) FIG. 2 is an enlarged illustration of the detail II in FIG. 1,

(5) FIG. 3 is a side elevational view of a second embodiment of the device, and

(6) FIG. 4 is an enlarged illustration of the detail IV in FIG. 3,

(7) FIGS. 1 and 2 illustrate a device comprising a sliding table 10 which can be displaced horizontally in order to move a foam material body 11 horizontally against a knife 12. The knife 12 is part of a splitting device 13. It is also possible to provide a stationary table 10 and to move the splitting device 13. The sliding table 10 includes means for retaining the foam material body 11 thereon, for example a suction device.

(8) The knife 12 is an endless band-knife circulating around knife discs (not illustrated) on a closed trajectory. The band-knife 12 has a front cutting edge 12a. It is arranged under an acute angle with respect to the surface of the foam material body 11 and is guided in a knife guide 15 formed by two guide plates 15a, 15b. The knife guide 15 leaves the cutting edge 12a of the knife 12 exposed so that the same can penetrate into the foam material body 11 in order to split off a layer 16 from the foam material body.

(9) The layer 16 is removed by the take-off device 20. The take-off device comprises a belt conveyor 21 with an endless conveyor element 22 circulating around guide rolls 23, 24. The belt conveyor 21 is oriented obliquely, with the lower guide roll 23 being positioned almost tangentially to the surface of the foam material body 11 before the layer 16 is split. The other guide roll 24 is placed higher so that the belt conveyor 21 carries the layer 16 away in a forward and upward direction, the transport being effected on the upper strand 22a. At a site along the belt conveyor 21, at which the layer 16 has already been taken from the conveyor element 22, an electrostatic charging device 25 is provided along which the conveyor element 22 moves. In the present instance, the charging device 25 is an ionization means for electrically charging the conveyor element made of non-conductive material. In this embodiment, the charging device 25 acts on the lower strand 22b of the conveyor element.

(10) The centre of the guide roll 23 is arranged at a distance from the surface of the foam material body that corresponds to the radius of the guide roll plus the thickness of the layer 16. The cutting edge 12a is located at that site of the layer 16 that is just lifted from the foam material body 11 by the guide roll 23. The cutting edge 12a thus enters the gap in the foam material formed by the guide roll 23. This means, the layer 16 is lifted from the foam material body 11 immediately at the cutting site and is removed by means of the take-off device 20. This allows for a controlled and interference-free continuous lifting and removal of the layer 16.

(11) In the embodiment illustrated in FIGS. 1 and 2, the layer 16 runs around the guide roll 23 in an angular range that is larger than 90 degrees, before it reaches the upper strand 22a. The layer 16 thus virtually folded back.

(12) The embodiment illustrated in FIGS. 3 and 4 is largely similar to the first embodiment with the difference that the material transport of the layer 16 is directed rearward, i.e. towards the knife guide 15. Again, the guide roll 23 is arranged tangentially to the surface of the non-split foam material body 11; however, the belt conveyor 21 in this embodiment is arranged such that it covers the knife guide 15. The layer 16 comes to lie on the bottom face of the lower strand 22b of the belt conveyor 21 and is transported away overhead as it were. The charging device 25 arranged opposite the upper strand 22a. In any event, the charging device is positioned such that it can charge the conveyor element 22 before it enters the cutting region so as to guarantee a homogeneous charging.

(13) The invention combines the cutting operation and the removal operation. It is important that not only the transport of the layer 16, but also the taking-off and the lifting are effected by electrostatic attraction immediately after the cutting operation. Thereby, the split-off material is transported uniformly and with a constant pull out from the cutting region.