US3823887A

US3823887A - Device for forming lightweight paper into rolls without any core

Info

Publication number: US3823887A
Application number: US00211319A
Authority: US
Inventors: D Gerstein
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-12-23
Filing date: 1971-12-23
Publication date: 1974-07-16
Anticipated expiration: 1991-07-16

Abstract

A device for coreless rolls of very lightweight fiber material, such as tissue, comprises feeding one or move continuous webs of the tissue material into juxtaposition and then for directing it into association with a perforator and a slitter. The paper which has been slit is then fed along a feed path onto winding mandrels. The windup of the tissue on the mandrel is effected by first wetting the edge so that it engages with the mandrel. The tissue is wound into a coil of predetermined thickness and it is broken away from the continuous web along the perforations by the simple expedient of moving a flat boardlike member upwardly through the path of movement of the tissue to sever it along the perforations. The end is guided along the roll by a semi-annular member which engages around the exterior surface of the tissue roll. Thereafter, the mandrel is released at one end and pivoted outwardly from its support and the wound tissue roll is pulled off an end thereof. It is also possible with an embodiment of the invention to feed the tissue which has been slit into guide tubes or folding gauges which fold them into one or more folds as they are wound into a coreless roll.

Description

United States Patent [191 Gerstein 51 July 16, 1974 DEVICE FOR FORMING LIGHTWEIGHT PAPER INTO ROLLS WITHOUT ANY CORE [76] Inventor: David E. Gerstein, 63-33 98th Pl.,

' Forest Hills, NY. 11374 [22] Filed: Dec. 23, 1971 21 Appl. No.: 211,319

[52] US. Cl 242/56.2, 242/56.8, 242/D1G. 3 [51] Int. Cl B65h 15/02, B65h 35/02 [58] Field of Search 242/56.2, 56.6, 56.7, 56.8,

242/D1G. 3; 93/84 R; 270/86, 93, 41

[56] References Cited UNITED STATES PATENTS 2,237,759 4/1941 Kwitek 242/56.'6 2,328,109 8/1943 Thompson 242/56.6 X 2,712,933 7/1955 Davidson 270/86 2,736,508 2/1956 Langbol 242/56 2,956,799 10/1960 Wasson 270/86 3,029,073 4/1962 Wright 270/86 3,096,039 7/1963 Doreb 242/56.2 3,680,806 8/1972 Obermaier 242/68 Primary Examiner-John W. Huckert Assistant Examiner-Edward J. McCarthy [5 7] ABSTRACT A device for coreless rolls of very lightweight fiber material, such as tissue, comprises feeding one or move continuous webs of the tissue material into juxtaposition and then for directing it into association with a perforator and a slitter. The paper which has been slit is then fed along a feed path onto winding mandrels. The windup of the tissue on the mandrel is effected by first wetting the edge so that it engages with the mandrel. The tissue is wound into a coil of predetermined thickness and it is broken away from the continuous web along the perforations by the simple expedient of moving a flat boardlike member upwardly through the. path of movement of the tissue to sever it along the perforations. The end is guided along the roll by a semi-annular member which engages around the exterior surface of the tissue roll. Thereafter, the mandrel is released at one end and pivoted outwardly from its support and the wound tissue roll is pulled off an end thereof. lt is also possible with an embodiment of the invention to feed the tissue which has been slit into guide tubes or folding gauges which fold them into one or more folds as they are' wound into a coreless roll.

13 Claims, 17 Drawing Figures 6 a a" l PATENTEU 1 5 I974 saw 2 0r 7 INVENTOR DAV/0 E. GEPSTE/N ATTORNEY PATENTEUwsmu 3.823.887

SHEET 10 (IF 7 INVENTOR.

04V/0 E. G'EPSTV/V ATTORNEY PATENTED JUL I 6 I974 SHEET 5 ii? 7 R m w m DAV/0 E. GE/PSTEM/ PATENTEDJUH s 1914 FIG. 9

ENTO DAV/D E. 65,7578

FIG. /2

. ATTORNEY DEVICE FOR FORMING LIGHTWEIGHT PAPER INTO ROLLS WITHOUT ANY CORE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to the construction of devices for rolling paper material into small size rolls and, in particular, to a new and useful device for effecting the rolling of a lightweight paper such as a tissue into coreless rolls of predetermined length and thickness.

2. Description of the Prior Art At the present time, there are known devices for slitting paper along longitudinal cutting lines to form the paper into individual roll lengths and for rolling these rolls onto cores. The core which is employed is usually a fiberboard material which does not interfere with the use of the tissue. For many present day applications, it is desirable that the tissue be wound without any fiberboard core and that the winding device provide means for easily separating the tissue into individual roll lengths and preferably for forming more than one roll length at a time. I

SUMMARY OF THE INVENTION In accordance with the present invention; there is provided a device which is capable of feeding very lightweight tissue into association with means for perforating it and for slitting it into individual lengths and for rolling each length into a coreless roll of predetermined lengths. A feature of the construction is that the individual lengths are fed, after slitting, into association with a mandrel where they are engaged with the mandrel by wetting the end of the tissue to cause it to adhere to the mandreLThe tissue is severed from the remaining length of tissue web after winding by moving a flat board upwardly through the path of movement of the tissue to sever it along a perforation line. It is to be understood that one continuous web of material may be utilized. However, in the following description, several thicknesses of tissue are fed to the perforator and slitter and they are separated after the slitting operation is carried out in order that there be a sufficient body of tissue paper presented for the slitting and perforation operation-when it is done. The rolls of paper, which are wound on mandrels, and are held to the mandrels by the wetting action, are removed from the mandrels after rolling by freeing the end of the mandrels and directing the tissue off the mandrels end after this end has been pivoted away from its support or cradle.

In accordance with another embodiment of the invention, thepaper'is directed after slitting into individual folding gauges which effect the folding of the paper as it is fed into one or more folds prior to it being fed onto the winding mandrel.

Accordingly, it is an object of the invention to provide a device for forming coils of lightweight paper, such as tissue, individual sheets and for perforating the sheet and for thereafter winding the perforated sheet on a mandrel, separating the individual rolls which are wound from the remaining sheets along the perforations, and then removing the sheets from the mandrel.

A further object of the invention is to provide a device for winding very lightweight paper which includes feeding one or more thicknesses of the paper into juxtaposition and then perforating and slitting the sheets together, subsequently folding them by passing them through folding guides and thereafter winding them without a core'directly on a mandrel from which they are remove.

A further object of the invention is to provide a winding mechanism which is simple in design, rugged in construction, and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed-to and forming a part of this disclosure. For a better understanding of the invention, it s operating advantages and specific objects attained by its uses, reference should be had to the accompanying drawing and descriptive matter in which there are illustrated preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWING In the Drawing: I

FIG. 1 is atop plan view of a device for winding lightweight papers into rolls without cores constructed in accordance with the invention;

. FIG. 2 is a schematic elevational view indicating the drive mechanism for the device shown in FIG. 1;

FIG. 3 is a schematic side elevational view showing the manner in which the paper webs are fed in the device shown in FIG. 1; I

FIG. 4 is an enlarged axial sectional view of aslitting mechanism;

FIG. 5 is an enlarged sectional view'of the perforating mechanism;

FIG. 6 is a partial-elevational view of the perforating blade used for the perforation mechanism;

FIG. 7 is a partial perspective view of the winding mandrel and'sheetwetting mechanism;

FIG. 8 is a view similar to FIG. 7 indicating the part in the position at the end of the winding of one complete roll of tissue on the mandrel;

FIG. 9 is a partial sectional view showing the breaking of the tissue along the perforation line;

FIG. 10 is a view similar to FIG. 9 indicating the manner in which the tissue is wrapped around the finished roll;

FIG. 11 is a partial top plan view indicating the manner in which the mandrel may be swung out of an operating position for the removal of the wound tissue therefrom;

FIG. 12 is a perspective view of a complete assembly of wound rolls which have been removed from'the mandrel;.

FIG. 13 is a partial top plan view indicating the folding gauges for folding the tissue prior to winding;

FIG. 14 is a side elevational view of the mechanism shown in FIG. 13;

FIG. 15 is a section taken along the line l5-15 of FIG. 14; and

FIGS. 16 and 17 are views similar to FIG. 15 of other embodiments of the invention. A

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings in particular, the invention as embodied therein and shown in FIGS. 1 through 12,

comprises a device for perforating, slitting and then In accordance with the invention, as shown in FIG. 3, preferably two lightweight paper webs or sheets and 12 are fed over dancer rolls 14 and 16 and combined onto a feed roll 18. One of the tissues is also guided by a guide roll 20. The combined

webs

10 and 12 move between the nip of the roller 18 and a counterroller 22 into association with perfrorating means, generally designated 24.

The perforating means 24 includes a rotatable perforator block 26 and a resilient counter-roller 28 which receives the perforating blade projections 32 of a perforating blade 34. (See FIG. 6). The blade 34 includes projections 32 spaced along the length of the blade and separated by recesses 36 which are located at the areas in which the tissue is not penetrated. The blade 34 is carried in a recess 38 of the rotatable block 26 and it is held in an adjusted position by a set screw 40, as shown in FIG. 6.

After the

webs

10 and 12 in their combined form, as generally designated 42, are passed through the perforator means 24, they are advanced into association with conventional slitter means 44.

After the passage of the combined webs 42 through the slitter means 44, they are moved to feed rolls, generally designated 58, and which include a top roller 57 and a lower roller 59 between which the combined webs are fed and separated into individual webs at 12' and 10'. The individual webs 10' and 12 have each been slit longitudinally and perforated transversely and each is wound upon an associated mandrel 60 and 62,

one pivotal universal switch bearing or joint 100 arranged atone end, after first lifting the opposite end off of a cradle 102, as shown in FIG. 11. All of the wound rolls 72 are removed at once from the mandrel 60 in a direction of the arrow 104, as shown in FIG. 11. Afterwards, the individual roll lengths 72 are separated by breaking them along the slit lines 70.

The drive for the operating mechanism shown in FIGS. land 2 and the main drive is from a drive motor (not shown) driving through a belt 106 to a sprocket 108 affixed to a shaft having a drive pinion 110. The

' drive pinion 110 is in meshing engagement with a large respectively, to form rolls 64 and 66. The rolls 64 and 66 are separated from the remaining portions of the webs 10.and 12 along the perforated lines.

The web winding operation begins, as shown in FIG. 7, in respect to the web 10', which has beenslit along a plurality of longitudinal slit lines 70 in order to define individual roll widths 72 (FIGS. 7 and 8) which will be separated'after they are removed from the associated mandrel 60. Initially, the leading edge of the web 10 is adhered to the mandrel 60 in any conventional way. When a predetermined thickness of tissue'material has been wound upon the mandrel 60, the winding is continued until the perforation line 78 aligns over a breakboard 80 which is part of the web separating means 68. The breaking of the tissue away from the remaining web 10 is effected by an operation in which the surface of the wound roll 72 is engaged by a half cylindrical shell or guide plate 84 and then by moving the breakboard 68 upwardly in a direction of the arrow 86 shown in FIG, 3.

The break of the tissue occurs along the perforation line 78, as shown in FIG. 9, and the broken end of the roll is smoothened over the surface of the roll by the guide plate 84. The break-board 80 is supported below the web feeding to the associated mandrel 60 or 62 on an upright member 90 which is hinged to the board by a hinge 92. The upright member may be oriented to engage the ground or some fixed support 94 when the break-board 80 is lowered back into an operating position, as shown in FIG. 3. The upper end of the breakboard is hinged to a fixed member 96 which carries a connecting hinge which is secured to the board. The hinge 98 permits upward pivotal movement of the break-board 80 as desired.

After the end of the roll has been severed from the remaining web, and deflected around the surface of the wound roll 72, the mandrel 60 is pivoted outwardly on gear 112 carried on a shaft 114 which carries a drive gear 116. The drive gear 116 drives a gear 118 which is affixed to the shaft 54 of the mandrel roller. This shaft 54 carries a sprocket 120 which drives a gear 122 through a chain 124 carrying a'shaft 126 of the lower separating roller 59 which is located below the feed roll 128. The gear 118 also drives a gear 130 to rotate the slitter shaft 52.

The gear 116 also drives a gear chain of

gears

132, 134, 136 and 138. The

gears

136 and 138 are on

shafts

140 and 142 of the counter-roller 28 and the perforator block 26, respectively.

The gear 138 also drives a chain of gears 144,146 and 148. The

gears

146 and 148 are on shafts 150 and 152 which carry

rollers

22 and 18, respectively. Shafts 154 and 156 carry the dancer rollers 14 and 16, respectively, as shown in FlG.'2. I

The rewind drive is taken from the large gear. 112

driving gear 158 which is on a shaft which carries a' sprocket 160 which drives a chain 162 to drive gears 164 and 166 which are located on the rewind shafts 168 and 170 for the mandrels 60 and 62, respectively. A tensioning sprocket 172 is engaged with the chain 162.

In FIGS. 13 to 15, there is shown another embodiment of the invention in which a web, generally desig- I nated 10", is separated into individual widths by slitter rollers 174 and the widths are directed into association with folding means, generally designated 176, which comprises a folding gauge or tubular member 178 through which the end of the sheet is initially guided by hand and out of which the sheet arrives as a folded individual sheet 180which' is directed over a mandrel 182. The tubular fold members 178 have an initial crosssection as indicated in FIG. 15 which gradually reduces from one end to the other to gradually carry out the complete folding operation so that there is a double folded layer which arrives at the mandrel 182.

FIGS. 16 and 17 show alternate embodiments of

guide tube

178 and 178" to effect a simple V-type fold as shown in FIG. 16 and a double fold asshown in FIG. 17.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principlesof the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is: r

1. A method of forming individual rolls of tissue paper'free of any core from a continuous web, comprising passing at least one continuous sheet of the tissue through a feed path while perforating the tissue at longitudinally spaced locations across the width thereof and slitting the tissue along at least one longitudinally extending slitting line to divide the tissue up into individual roll lengths, winding the perforated and slit tissue directly onto a mandrel, and, after a predetermined thickness is wound on the mandrel, separating the rolled tissue from said web and removing the rolled tissue from said mandrel, whereby said rolled tissue is free of core and mandrel.

2. A method according to claim 1, including feeding the tissue to the mandrel over a movable surface, and moving the movable surface through the path of movement of the slit and perforated tissue to move the end of said movable surface through the tissue, at the location ofone of the perforations, to sever the roll of tissue from the remaining portion thereof.

3. A method of forming individual rolls of tissue paper free of any core from a continuous web comprising passing at least two webs into juxtaposition to form a combined sheet and thereafter passing the combined sheet through a feed path while perforating said combined sheet at longitudinally spaced locations across the width thereof and slitting the combined sheet along at least one longitudinally extending slitting line to divide said combined sheet'into individual rolled lengths, winding said perforated and slit combined sheets of tissue onto a mandrel and after a predetermined thickness is wound upon said mandrel, removing it from said mandrel.

4. A method of forming individual rolls of tissue paper free of any core from a continuous web comprisving passing at least one continuous sheet of tissue through a feed path while perforating the tissue at longitudinally spaced locations across the width thereof and slitting the tissue along at least one longitudinally extending slitting line to divide the tissue up into individual roll lengths, passing the slit end perforated tissue into a.folding gage to fold it into one or more layers, winding the perforated slit and folded tissue onto a mandrel, and, after a'predetermined thickness is wound on the mandrel, removing the rolled tissue from the mandrel.

5. A device for forming individual rolls of fibrous material such as tissue paper free of any core and from a continuous web, comprising means for feeding a continuous web of fibrous material through a feed path, slitting means arranged along said feed path for slitting the fibrous material along its length as it is fed in order to divide it up into a plurality of lengths of fibrous material, perforating means along the feed path engageable with the'fibrous material to perforate the fibrous material acoss the width thereof at spaced locations 7 along its length as it is fed, a rotatable mandrel upon which the web is wound rotatably mounted at the end of said feed path, means mounting said mandres for rotation about an axis which extends substantially transversely to the feed path, and means adjacent said mandrel for tearing the wound fibrous material on the mandrel away from the remaining web, and means for detachably connecting said mandrel relative to said mounting means to facilitate the removal of the rolled web wound thereon.

6. A device according to claim 5, wherein said tearing means comprises a flat surface over which the web is moved to the mandrel, said surface being displaceable to cause the edge thereof to move through the web adjacent the perforations in order to sever the web across its width.

7. A device for forming individual rolls of fibrous material such as tissue paper, free of any core and from a continuous web, comprising means for feeding a continuous web of fibrous material through a feed path, slitting means arranged along said feed path for slitting the fibrous material along its length as it is fed in order to divide it up into a plurality of lengths of fibrous ma terial, perforating means along the feed path engageable with the fibrous material to perforate the fibrous material across the width thereof at spaced locations along its length as it is fed, a rotatable mandrel upon which the web is wound rotatably mounted at the end of said feed path, means mounting said mandrel for rotation about an axis which extends substantially transversely to the feed path, and means adjacent said mandrel for tearing the wound fibrous material on the mandrelaway from the remaining web, wherein said feeding means comprises means for feeding two separate webs of fibrous material into juxtaposition and foil-sub;

sequently feeding it through a feed path.

8. A device for forming individual rolls of fibrous 1155-,

terial such as tissue paper, free of any core and from a continuous web, comprising means for feeding a continuous web of fibrous material through a feed path, slitting means arranged along said feed path for slitting the fibrous material along its length as it is fed in order to divide it up into a plurality of lengths of fibrous material, perforating means along the feed path engageable with the fibrous material to perforate the fibrous material across the width thereof at spaced locations along its length as it is fed, a rotatable mandrel upon which the web is wound rotatably mounted at the end of said feed path, means mounting said mandrel for rotationabout an axis which extends substantially transversely to the feed path, and means adjacent said mandrel for tearing the wound fibrous material on the mandrel away from the remaining web, wherein said tearing means comprises a pivotal support plate over which the web is fed to said mandrel, a pivot leg connected to said plateadjacent the free end thereof and supporting said plate on the ground at an elevation over which the web may be fed to said mandrel, said plate being'movable about its pivot through the path of feed of the web material to tear it away from the material which has been wound on the mandrel.

9. A device according to claim 8, including a holding plate associated with said mandrel and engageable over the material wound thereon, said plate having an interior curvature comparable to the curvature of the material wound on the mandrel and being movable over the material to smooth it over the mandrel and to hold it in position while the material is cut away from the continuous web.

10. A device for forming individual rolls of fibrous material such as tissue paper, free of any core and from a continuous web, comprising means for feeding a continuous web of fibrous material through a feed path, slitting means arranged along said feed path for slitting the fibrous material along its length as it is fed in order to divide it up into a plurality of lengths of fibrous material,'perforating means along the feed path engageable with the fibrous material to perforate the fibrous material across the width thereof at spaced locations along its length as it is fed, a rotatable mandrel upon which the web is wound rotatably mounted at the end of said feed path, means mounting said mandrel for rosage means includes two passage portions extending obliquely at an angle from each other which gradually diminishes to fonn two folds of material.

13. A device according to claim 10, wherein said passage means includes a plurality of passage portions extending in a zig-zag formation which gradually diminishes in order that the paper is formed into three separate folds, one back upon the other.

Claims

1. A method of forming individual rolls of tissue paper free of any core from a continuous web, comprising passing at least one continuous sheet of the tissue through a feed path while perforating the tissue at longitudinally spaced locations across the width thereof and slitting the tissue along at least one longitudinally extending slitting line to divide the tissue up into individual roll lengths, winding the perforated and slit tissue directly onto a mandrel, and, after a predetermined thickness is wound on the mandrel, separating the rolled tissue from said web and removing the rolled tissue from said mandrel, whereby said rolled tissue is free of core and mandrel.

2. A method according to claim 1, including feeding the tissue to the mandrel over a movable surface, and moving the movable surface through the path of movement of the slit and perforated tissue to move the end of said movable surface through the tissue, at the location of one of the perforations, to sever the roll of tissue from the remaining portion thereof.

3. A method of forming individual rolls of tissue paper free of any core from a continuous web comprising passing at least two webs into juxtaposition to form a combined sheet and thereafter passing the combined sheet through a feed path while perforating said combined sheet at longitudinally spaced locations across the width thereof and slitting the combined sheet along at least one longitudinally extending Slitting line to divide said combined sheet into individual rolled lengths, winding said perforated and slit combined sheets of tissue onto a mandrel and after a predetermined thickness is wound upon said mandrel, removing it from said mandrel.

4. A method of forming individual rolls of tissue paper free of any core from a continuous web comprising passing at least one continuous sheet of tissue through a feed path while perforating the tissue at longitudinally spaced locations across the width thereof and slitting the tissue along at least one longitudinally extending slitting line to divide the tissue up into individual roll lengths, passing the slit end perforated tissue into a folding gage to fold it into one or more layers, winding the perforated slit and folded tissue onto a mandrel, and, after a predetermined thickness is wound on the mandrel, removing the rolled tissue from the mandrel.

5. A device for forming individual rolls of fibrous material such as tissue paper free of any core and from a continuous web, comprising means for feeding a continuous web of fibrous material through a feed path, slitting means arranged along said feed path for slitting the fibrous material along its length as it is fed in order to divide it up into a plurality of lengths of fibrous material, perforating means along the feed path engageable with the fibrous material to perforate the fibrous material acoss the width thereof at spaced locations along its length as it is fed, a rotatable mandrel upon which the web is wound rotatably mounted at the end of said feed path, means mounting said mandres for rotation about an axis which extends substantially transversely to the feed path, and means adjacent said mandrel for tearing the wound fibrous material on the mandrel away from the remaining web, and means for detachably connecting said mandrel relative to said mounting means to facilitate the removal of the rolled web wound thereon.

7. A device for forming individual rolls of fibrous material such as tissue paper, free of any core and from a continuous web, comprising means for feeding a continuous web of fibrous material through a feed path, slitting means arranged along said feed path for slitting the fibrous material along its length as it is fed in order to divide it up into a plurality of lengths of fibrous material, perforating means along the feed path engageable with the fibrous material to perforate the fibrous material across the width thereof at spaced locations along its length as it is fed, a rotatable mandrel upon which the web is wound rotatably mounted at the end of said feed path, means mounting said mandrel for rotation about an axis which extends substantially transversely to the feed path, and means adjacent said mandrel for tearing the wound fibrous material on the mandrel away from the remaining web, wherein said feeding means comprises means for feeding two separate webs of fibrous material into juxtaposition and for subsequently feeding it through a feed path.

8. A device for forming individual rolls of fibrous material such as tissue paper, free of any core and from a continuous web, comprising means for feeding a continuous web of fibrous material through a feed path, slitting means arranged along said feed path for slitting the fibrous material along its length as it is fed in order to divide it up into a plurality of lengths of fibrous material, perforating means along the feed path engageable with the fibrous material to perforate the fibrous material across the width thereof at spaced locations along its length as it is fed, a rotatable mandrel upon which the web is wound rotatably mounted at the end of said feed path, means mounting said mandrel for rotation about an axis wHich extends substantially transversely to the feed path, and means adjacent said mandrel for tearing the wound fibrous material on the mandrel away from the remaining web, wherein said tearing means comprises a pivotal support plate over which the web is fed to said mandrel, a pivot leg connected to said plate adjacent the free end thereof and supporting said plate on the ground at an elevation over which the web may be fed to said mandrel, said plate being movable about its pivot through the path of feed of the web material to tear it away from the material which has been wound on the mandrel.

10. A device for forming individual rolls of fibrous material such as tissue paper, free of any core and from a continuous web, comprising means for feeding a continuous web of fibrous material through a feed path, slitting means arranged along said feed path for slitting the fibrous material along its length as it is fed in order to divide it up into a plurality of lengths of fibrous material, perforating means along the feed path engageable with the fibrous material to perforate the fibrous material across the width thereof at spaced locations along its length as it is fed, a rotatable mandrel upon which the web is wound rotatably mounted at the end of said feed path, means mounting said mandrel for rotation about an axis which extends substantially transversely to the feed path, and means adjacent said mandrel for tearing the wound fibrous material on the mandrel away from the remaining web, and including tubular guide means adjacent said mandrel through which the slit and perforated material is directed, said tubular guide means including a passage means defined therein causing the folding of the web material as it is moved therethrough.

11. A device according to claim 10, wherein said passage means is arranged in a U-shape which gradually diminishes to form two folds.

12. A device according to claim 10, wherein said passage means includes two passage portions extending obliquely at an angle from each other which gradually diminishes to form two folds of material.