US3898711A

US3898711A - Continuous soft mat perforator

Info

Publication number: US3898711A
Application number: US404068A
Authority: US
Inventors: Vliet Raymond August Van
Original assignee: Weyerhaeuser Co
Current assignee: Weyerhaeuser Co
Priority date: 1973-10-05
Filing date: 1973-10-05
Publication date: 1975-08-12
Anticipated expiration: 1992-08-12

Abstract

An endless perforated band is supported on two opposed end rolls such that it can be continually driven while carrying a suitable soft mat along its top surface. At a preforating station, a rotating brush is positioned beneath the perforated band such that its bristles will extend through the perforations in the band. A top pressure roll is positioned above the endless band at the perforating station and lightly presses the soft mat toward the rotating brush and against the continuously moving perforated band. The rotating brush acts to remove material from the soft mat in order to form perforations or depressions therein.

Description

United States Patent 1 Van Vliet CONTINUOUS SOFT MAT PERFORATOR [75] Inventor: Raymond August Van Vliet, Castle 21 Appl. No.: 404,068

[52] US. Cl. 19/161 P [51] Int. Cl. D0411 11/00 [58] Field of Search 19/161 P; 161/109, 169;

[56] References Cited UNITED STATES PATENTS 3,113,349 12/1963 Nottebohm et a1. 19/161 P OTHER PUBLlCATlONS (Saruhashi) No.

Japanese Patent Publication Aug. 12, 1975 1831 l/l962 Published Nov. 27, 1962.

Primary Examiner-Dorsey Newton [5 7 ABSTRACT An endless perforated band is supported on two opposed end rolls such that it can be continually driven while carrying a suitable soft mat along its top surface. At a preforating station, a rotating brush is positioned beneath the perforated band such that its bristles will extend through the perforations in the band. A top pressure roll is positioned above the endless band at the perforating station and lightly presses the soft mat toward the rotating brush and against the continuously moving perforated band. The rotating brush acts to remove material from the soft mat in order to form perforations or depressions therein.

7 Claims, 6 Drawing Figures tlONTINUOUS SOFT MAT PERFORATOR BACKGROUND OF THE INVENTION This invention relates generally to an apparatus for processing soft mat material and more particularly to an apparatus for forming depressions or perforations in a continuously moving soft mat.

Soft mats comprised, for example, of loosely compacted cellulosic fluff pulp have many uses. Among the more common uses are for disposable diapers, sanitary napkins, incontinent pads, and the like. The basic composition of the soft mat material is loosely compacted cellulosic fibers which have been formed into a mat by any suitable known means, such as through an air laying process. A suitable binder may be added. When the mat material comes from the forming process, it is highly susceptible to tearing if not handled properly.

One end product that utilizes the soft mat material b requires that it have a plurality of perforations or indentations in the material. Of course, in view of the inherent weakness in a soft mat of this type, the problem was one to conceive a suitable process for establishing the desired perforations or indentations.

Thus, from the foregoing, one object of the present invention is to provide an apparatus that establishes perforations or indentations in the surface of a soft mat material.

Another object is to establish such perforations or indentations in a manner that does not cause disintegration or tearing of the mat material and forms a clean perforation or depression.

Yet another object is to provide such an apparatus to accomplish these foregoing objects that operates in a continuous and efficient manner.

These and other objects ofthe invention will become apparent upon reading the following specification in conjunction with the attached drawing.

SUMMARY OF THE INVENTION A continuously moving perforated band operates to carry a soft mat material through a perforating station where a rotating brush acts to form the perforations or depressions in the surface of the mat material. The rotating brush is positioned beneath the moving band and cooperates with a top pressure roll or platen such that the brush will remove material from the mat through the perforations in the band. A suitable conveying system placed beneath the rotating brush can operate to carry the removed mat material away from the apparatus in order to recycle it.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a perspective view showing, in simplified form, the apparatus of the present invention.

FIG. 2 is a side elevation view also showing in simple form the apparatus of the present invention.

FIG. 3 is a section view taken along line 33 of FIG. 2.

FIG. 4 is a view similar to FIG. 3, but taken along section line 44 of FIG. 2 and showing the rotating brush as it sweeps material from the soft mat.

FIG. 5 is a cross-section view taken along line 55 of FIG. 2 and shows the moving soft mat after it has depressions formed in its bottom surface.

FIG. 6 is a section view taken along line 6-6 of FIG. 4 and shows in detail the rotating brush removing material from the soft mat.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. I, the overall perforating or depression forming apparatus is generally indicated at 2. An endless band 4, comprised of suitable material such as stainless steel, is supported by a pair of spaced end rolls 6 and 8, respectively. Each roll 6, 8 is mounted on a

rotatable shaft

10 and 12, respectively, such that the endless band 4 will be constrained to travel longitudinally over the two spaced end rolls 6, 8.

The endless band 4 has a plurality of apertures 14 positioned over its surface. The apertures 14 are generally formed and spaced in a predetermined pattern, depending on the type of pattern to be formed on the workpiece, which is depicted at 16. As will be seen by referring to FIG. I, the directional arrows placed on the end rolls 6, 8 indicate the direction of rotation which will motivate the endless band 4 in the longitudinal direction; this direction being indicated by the large directional arrows at either end of workpiece 16. The width of the endless band 4 will generally be equal to the width of the workpiece 16.

Generally, on the top section of the endless band 4 and midway between the pair of end rolls 6, 8 is the perforating or depression forming station generally depicted at 18. The station 18 is comprised of a vertically spaced pair of cooperating rotating members, one of which is the rotatable brush or sweeping member 20. Brush member 20 is positioned slightly below the lower surface of the endless band 4 such that the outer ends of bristles 22 will penetrate the apertures 14 when the brush member 20 is rotating and the endless band 4 is moving longitudinally above the brush. During operation, the direction of travel for the rotatable brush is as shown in the figures being the direction opposite to that of endless band 4. Positioned directly above the rotating brush member 20, but on the top of the endless band 4, is the rotatable pressure roll 24, which is powered through any suitable means so as to rotate in the same direction as the endless band 4 travels longitudinally. It will be apparent to those skilled in the art that a platen or idling roll could be substituted for pressure roll 24 and stiff offer the same backing function.

As depicted in FIG. I, the workpiece 16 or the soft mat material is carried into station 18 atop the endless band 4. Suitable means (not shown) are upstream of apparatus 2 and cause the workpiece I6 to travel into the apparatus 2. At station 18, the workpiece 16 will be gently pressed against the top surface of endless band 4 by pressure roll 24. Suitable means (not shown) can be provided for varying the pressure applied by the pressure roll 24, depending on the actual composition of the workpiece or the amount and depth of material to be removed from the workpiece.

Also depicted in the figures is a conveying system 26 that extends in a direction generally transversely to the direction of travel of the endless band 4. Conveyor system 26 can take several forms but in the figures is comprised of an endless belt member 27 which is supported at either end by rotatable rollers 28. The belt member 27 is positioned directly beneath the brush member 20 in order to collect on its top surface the soft mat material that is being removed at station 18. By referring to FIG. 2, a collected mass of fiber material 30 is depicted on the surface of belt 27. It will be obvious to those skilled in the art that since the belt 27 will be moving transversely to that of the endless band 4, it will carry the collected fiber to a suitable downstream collection area for recycling or the like. An alternate form for conveying system 26 would be a pneumatic conveyor that has as its components a chamber surrounding the brush member with a slight vacuum applied thereto. A conduit would lead from the chamber to carry the removed fiber away. The slight vacuum would also help to hold mat 16 against band 4.

Operation of the Invention As previously noted, a continuous supply of soft mat material is directed into station 18. The top pressure roll 24 will act to compress lightly and hold the workpiece 16 as it travels through the perforating or depression forming station. The bristles 22 on the rotating brush member 20 will be extending upwardly and passing through the apertures 14 and mechanically removing a portion of the fiber material that is directly above each of the passing apertures. The removing action is schematically depicted in FIG. 6 with the bristles 22 mechanically extending through the apertures and up into the soft mat material, sweeping a portion of the material back through and from the particular aperture. Thusly, there are formed the plurality of perforations or depressions 32 within workpiece 16.

The depth of the depression can be varied and, in fact, a perforation completely through the workpiece may be formed, depending on the amount of pressure applied to the top of workpiece 16 by roll 24. One ex ample of a suitable operating condition would be where the endless band 4 and the top pressure roll 24 are traveling at approximately 250 feet per minute. The rotating brush member 20 is powered so as to rotate at approximately 3600 rpm. The bristles 22 would be comprised of nylon approximately 0.040 inches thick. The endless band 4 would be comprised of stainless steel approximately 0.025 inches thick, while the top pressure roll 24 and end rolls 6, 8 would be comprised of flat steel rolls. The above operating conditions and suggested materials are given by way of example only and are not intended to limit the operating parameters or structure of the present invention. Other operating conditions and materials can be employed, depending upon the type of workpiece passing through station 18.

While a detailed example of the principal embodiment has been described, it is understood that many changes and modifications may be made in the above described perforating apparatus without departing from the spirit of the invention. All such modifications are intended to be included within the scope of the appended claims.

I claim:

1. An apparatus for forming apertures in soft mat material at a forming station comprising:

a perforated band adapted to carry the soft mat material on one surface thereof through the forming station, and

a sweeping member positioned at the forming station in engagement with the opposite surface of the per forated band and having means adapted to extend through the perforations and to move faster relative to the perforated band in order to sweep a portion of the soft mat material back through and from the perforations as the mat material is carried through the forming station.

2. The apparatus as in claim 1 further comprising pressure exerting means bearing against the soft mat material at the forming station.

3. The apparatus as in claim 2 in which the pressure exerting means is a rotatable roll adapted to rotate in the direction of travel of the soft mat material.

4. The apparatus as in claim 1 in which the sweeping member is a rotatable brush.

5. The apparatus as in claim 4 in which the brush is adapted to rotate in the direction opposite to that of the soft mat material.

6. The apparatus as in claim 1 in which the perforations in the band are positioned according to a predetermined pattern.

7. The apparatus as in claim 1 further including means to collect and transport the removed soft mat material away from the forming station.

Claims

1. An apparatus for forming apertures in soft mat material at a forming station comprising: a perforated band adapted to carry the soft mat material on one surface thereof through the forming station, and a sweeping member positioned at the forming station in engagement with the opposite surface of the perforated band and having means adapted to extend through the perforations and to move faster relative to the perforated band in order to sweep a portion of the soft mat material back through and from the perforations as the mat material is carried through the forming station.