The prior art

The invention relates to a method of manufacturing a plastics filling material in the form of sheet elements of individual, thin pieces of sheet for use as a filling in pillows, duvets, jackets and the like, said sheet element being manufactured by separation of a web of sheet. Moreover, the invention re- lates to a system for performing the method.

Filling material of this type, comprising small sheet elements of wavy shape, is very suited as a filling in bedclothes, etc., since the material forms a filling mass which is suitably soft and resilient, and which has suitable insulating properties.

Previously known fillings are preferably manufactured by cutting up a layer of sheet material and deforming this material between for instance two rollers.

An example of such a manufacture of plastics sheet elements is known from DK/EP 0 476 012. The drawback of this method is that it is very slow, and that the manufacturing capacity is poor. To this should be added a relatively large consumption of energy, and the poor possibilities of switch- ing the method to the generation of various element sizes and shapes.

An example of the manufacture of aluminium sheet elements is known from JP 60230921. This system comprises a housing in which a drum having loosely hanging hammers is rotated. The aluminium sheet is fed to the crusher via a funnel and is crushed between the hammers and a screen. Via the holes in the screen, the crushed sheet elements are sucked out via a suction line.

This system has a limited capacity, just as the manufactured aluminium filling material has a poor filling capacity.

The object of the invention

It is the object of the invention to remedy these deficiencies and drawbacks, and this is achieved according to the invention by a method, in which a web of plastics sheet is fed to a shredder system in the form of a housing in which a drum having loosely hanging knives is rotated, said web of sheet extending in a space between the outermost path of the knives and an outer screen, said screen being provided with through holes/openings so that the pieces of sheet may be sucked out through the screen.

In this surprisingly simple manner, it is possible to manufacture a considerable amount of pieces of sheet having a heretofore unknown bent shape and thereby resilient property, thereby providing partly a great manufacturing capacity, partly a good "filling capacity" because of the very wavy ele- ments. To this should be added the relatively great mutual distance between the individual elements and thereby the high degree of elasticity and insulating capacity. In practice, this filling has been found to be more comfortable than previously known sheet fillings. Also achieved is an "arbitrary" wave shape of the individual elements, since the knives will attack the sheet from various directions and at various distances and thereby at various impact angles.

When, as stated in claim 2, several layers of sheet are fed at the same time, a multiplication of the manufacturing capacity will be achieved. When, as stated in claim 3, use is made of a drum consisting of circular discs mounted on a shaft which constitutes a roller on which loosely hanging knives are mounted, these will be able serve as beaters and beat against the web of sheet for cutting as well as twisting, i.e. deformation, in many different directions.

When, as stated in claim 4, the web of sheet is fed as layers of sheet put together, the sheet elements may be dimensioned more easily, as the size and the shape of the individual elements may be changed by changing the feeding of the sheet.

When, as stated in claim 5, the screen is arranged on the lower side of the path of the drum, the sheet elements will accumulate there and will easily pass out through the holes in the screen.

Finally, as stated in claim 6, it is expedient to suck the elements out through the screen by means of vacuum, and, hereby, it will also be possible to sort out small particles, if any. The drawing

An example of an embodiment of the invention will be described more fully below with reference to the drawing, in which fig. 1 shows a section through a system for the manufacture of sheet elements seen in the direction l-l in fig. 3, fig. 2 shows an enlarged section of part of a drum, working gap and screen, fig. 3 shows a section through the system seen in the direction Ill-Ill in fig. 1 , and fig. 4 shows an enlarged sheet element according to the invention. Description of an exemplary embodiment

Figs. 1 - 3 show an example of a system for the manufacture of a filling material in the form of sheet elements, a single one of which is shown in fig. 4.

The sheet used is a generally known PE sheet with a thickness of about 12 - 18 μηι. As shown in fig. 1 , basically, rolled-up sheet may be suspended in a number from one roll and upwards. Three suspended rolls 1 - 3 are shown in the figure.

From there, a web of sheet 4 is rolled out, which is then either single-layered or multi-layered, and which is fed by feeding rollers 5 to a shredder system, which is incorporated in a housing 6 in the example shown. A drum 9 is mounted in the housing, said drum being rotated on a shaft 10 by means of a motor (not shown).

The drum 9 is composed of circular discs 18, which are mounted on the shaft 10 with spaces between adjacent discs.

Bearing rods 11 are mounted near the circumference and extend in parallel with the shaft 10, but near the circumference of the discs. Fig. 1 shows three bearing rods 11 , but there may be fewer or more. A knife 12 is suspended in each space, said knife being able to swing out and in between the discs when the drum is rotated. The individual knives 12 will serve as cutting and beating elements corresponding to choppers during the rotation of the drum 9.

The drum 9 has mounted therearound a guide plate or a shield 7 at the top, a plate for guiding the web of sheet 4 after the feeding plate which serves as a guide plate 17, while a screen 8 is mounted on the lower side of the drum, said screen being curved to create a gap 13, as shown in fig. 2.

The screen 8 is a plate in which holes or openings 14 are provided. These holes 14 have such a size that sheet elements 19 will be formed when the knives 12 work the sheet 4 against the screen 8 and the openings 14.

This working takes place in the gap 13 between the discs 18 of the drum and the screen 8, as will appear from fig. 2. It is noted that the knives 12 do not touch the screen 8 during the movement.

Below the screen 8, vacuum is established in the space 15 by means of a pump 16. This vacuum will draw the sheet elements 19 out through the openings 14 and move them further out via channels, etc. in the direction of the arrow 17.

Then, filtering of small particles, dust, etc. from the finished sheet elements 19 may take place in a generally known manner. The method will be described now.

The drum 9 is caused to rotate at a suitable speed, which may be varied according to the dimensions of the sheet elements. Then, the feeding rollers 5, the web of sheet 4 are moved into the space 13 between the screen 8 and the knives 12 in their extended position. The knives 12 will then work the sheet, as they will partly cut the sheet into small pieces, partly pull and twist these pieces to form a "curly" sheet element 19, as indicated in fig. 4. The dimensions of a single element 19 may be about 10 - 20 mm on each side. Following this working, the elements 19 are sucked out through the openings 14 in the screen 8 and further on for possible filtration and packaging. The method provides a considerable degree of adjustability to achieve the specific properties of the filling material.

For one thing, the sheet may be dimensioned, of course, and the number of sheet layers may be varied, but in addition the degree of feed, the speed of rotation of the drum and the size of the vacuum may be adjusted.