JPH0923907A - Fixing body for sheet material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily attach a fixing body provided with the same form to the planar attachment body of a different distance between fitting groove parts by providing a dimension in a width direction sufficient for fitting and fixing the fitting edge part of a planar base part inside the fitting groove part of the attachment body in the state of being folded into two along a length direction. SOLUTION: This fixing body 1 for a sheet material is provided with the planar base part 3 provided with a length approximately same as the attachment body 2, a width dimension W approximately equal to the distance between the bottom surfaces of both fitting groove parts 2c and a thickness T approximately equal to the opening width dimension of the fitting groove parts 2c. On a surface at a center part excluding both end edge parts 3a in the width direction of the planar base part 3, many hook-like engagement elements 4 are projected and molded integrally with the planar base part 3. Then, the width dimension S of both end edge parts 3a in the width direction of the planar base part 3 is turned to the dimension which is approximately the double of the groove depth D of the fitting groove parts 2c provided with an U-shaped cross section of the attachment body 2. Thus, the fixing body 1 provided with the same form is easily attached to the planar attachment body 2 of the different distance between the fitting groove parts 2c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastening body for fastening various sheet materials to a mounting portion, and more specifically to various curtains such as curtains, projection screens, dark curtains, and hanging curtains for advertisement. The present invention relates to a belt-shaped fastening body having a large number of male engaging elements of a surface fastener made of synthetic resin, which is used for hanging on a hanging portion or for fixing interior materials such as various wallpapers and carpets to various panels.

[0002]

2. Description of the Related Art Conventionally, when attaching a curtain to a curtain rail having a substantially C-shaped cross section, for example, a male engaging element made of a synthetic resin and having a plurality of hooks in the length direction of the curtain rail is used as a base portion. A belt-shaped curtain fastening body which is formed integrally with the flat base portion so as to project from the surface is fitted and fixed, and the female engaging piece of the surface fastener provided along the upper edge of the curtain is engaged with the male engaging member. It has been proposed that the curtain is fixed to the curtain rail by engaging with a curtain fastening body having an element. For example, as disclosed in Japanese Utility Model Laid-Open No. 5-70313, such a fastening body is not limited to use for curtains, and is used to fix interior materials such as various wallpapers and carpets to various panels (walls, floors). used.

In addition to the above-mentioned structure, the fastening body disclosed in this publication has a row of projections which are intermittently projected on one surface along both widthwise edges (ears) of the band-shaped fastening body. The projection row is formed and inserted into, for example, the fitting portion of the curtain rail, and the projection row is pressed by the inner wall surface of the fitting portion of the curtain rail to firmly fix the fastening body to the curtain rail. It is a thing.

[0004]

However, according to the fastening body disclosed in the above publication, the fastening body is pressed by the inner wall of the fitting groove of the flat plate-shaped mounting body due to the presence of the row of protrusions, so that the fastening body is firmly fixed. However, the engaging element projecting surface of the fastening body base is lower than the height of the fitting groove by the height of the projection row, and the engaging element projecting from the base projects to the upper surface of the mounting body. In order to secure the required engagement rate, the height of the rising portion of the engagement element must be set higher by the height of the projection row. This means
With the same thickness, it means that the rising portion of the engaging element is extremely easily bent, and it becomes difficult to obtain ideal engaging strength as the engaging element.

Further, for example, when the height of the rising portion of the engaging element is a normal height and the curved portion thereof sufficiently projects upward from the fitting groove portion of the mounting body, it is disclosed in the above publication. The structure of the fastening body has the following problems.

That is, the mounting body of this kind is generally continuously manufactured by extruding a long material having a predetermined sectional shape from a metal material. In this case, the cross-sectional dimension of the shape member, particularly the distance between the fitting groove portions formed along both end edges in the width direction is not necessarily uniform. On the other hand, the fastening body is made of a thermoplastic synthetic resin material and is continuously molded by injection or the like. However, considering the production efficiency and the like, changing the mold or the like is not always a good idea and the same width is used. And it is desirable to mass-produce the fastening body having the same shape.

Therefore, like the fastening body disclosed in the above publication, a row of protrusions is formed along the edge in the width direction, and the row of projections is attached when the fastening body is mounted on the mounting body of the other party. In order to surely fit into the fitting groove portion of the mounting body, it is necessary to prepare various dimensions in order to adapt the width dimension of the fastening body to the distance between the fitting groove portions of the mounting body. Further, in order to easily attach the fastening body to the mounting body, it is necessary to set the height of the projection row to be slightly lower than the opening height of the fitting groove portion. Does not allow firm mounting, or it becomes impossible to mount the row of protrusions into the fitting groove.

The present invention has been made to solve the above problems, and more specifically, facilitates attachment of a fastening body having the same shape to a flat plate-shaped attachment body having different distances between fitting groove portions. It is an object of the present invention to provide a sheet material fastening body which can secure the desired engagement ratio and engagement strength while strengthening its attachment and fixation.

[0009]

SUMMARY OF THE INVENTION The above-mentioned object is to provide an attachment having a fitting groove portion having a substantially U-shaped cross section, in which openings are formed so as to face each other along both widthwise edges of the present invention. A fastening member for a sheet material, which is fitted and fixed in the fitting groove portion of a body, for joining and fixing various sheet materials, wherein the fastening member is inserted in the fitting groove portion at both widthwise edges thereof. A flat base having a fitting edge, and a plurality of male engaging elements made of synthetic resin of a surface fastener integrally projecting from one surface between the fitting edges of the flat base, The fastening of the sheet material, wherein the edge portion has a dimension in the width direction sufficient to be fitted and fixed in the fitting groove portion of the attachment body in a folded state along the lengthwise direction. Achieved by the body.

Preferably, a concave groove or an uneven surface is formed along the fold line of the fitting edge portion, and further, the fitting edge portion is in the same plane as the flat plate-like base portion, and the width dimension thereof is It may be set to be larger than the groove depth of the fitting groove portion, and may have intermittent notches in the length direction of the fitting edge portion. Further, according to another preferable aspect, a half portion of the fitting edge portion corresponding to the outside of the fold line is raised substantially perpendicularly to the projecting side surface of the male engaging element, and at the tip portion thereof. It has an engaging piece extending substantially parallel to the surface of the flat base portion. Furthermore, as a modification thereof, an elastic piece that is raised substantially perpendicularly to the protruding side surface of the engaging element along the length direction from the width center of the substantially half portion of the fitting edge portion corresponding to the outside of the above-mentioned two-fold line. You may have.

Then, the thickness of the flat base portion is substantially equal to the height dimension of the fitting groove portion, and the thickness of the fitting edge portion is made smaller than that of the flat base portion, whereby the flat base portion is formed. At least the curved portion, which is the engaging portion, of the engaging element provided on the surface of the mounting member is surely exposed above the fitting groove portion of the mounting body, and the required engaging strength and engaging rate are secured.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION One of the typical and most preferred embodiments of the present invention is that a flat plate-shaped mounting body is, for example, a curtain rail applied to a curtain device that opens and closes a curtain up and down. L-shaped attachment pieces are integrally extended along both widthwise edges of the flat plate-shaped attachment portion, and the both edge portions face each other and have a substantially U-shaped cross section. Make up. Such a structure is substantially the same as the conventional mounting body.

On the other hand, the fixing member for sheet material has a length substantially equal to the length of the curtain rail, a width dimension substantially equal to the distance between the bottom surfaces of the two fitting groove portions, and a thickness thinner than the opening height of the fitting groove portions. In addition to having a flat plate-shaped base portion having a thickness, a large number of hook-shaped engaging elements integrally formed with the base portion are formed on one surface of the central portion excluding both widthwise end edges of the flat plate-shaped base portion. doing. This hook-shaped engaging element has no difference from the shape of the engaging element in a normal molded surface fastener, but the hook-shaped engaging element has a mushroom-shaped or bilobed curved portion instead of the hook-shaped. Of course, a male engaging element is also possible.

Further, according to the present invention, the thickness of the flat base portion is set to be smaller than the opening height of the fitting groove portion of the mounting body, and the width dimension thereof is the distance between the upper and lower edges of the vertical fitting groove portion of the curtain rail. It is set larger. The width dimension is such that the width of each fitting edge portion (ear portion) extending on the same plane from both edges of the area where the engaging element of the flat plate-shaped base is projecting is equal to the groove depth of the upper and lower fitting groove portions. It is preferable that the number is set twice or more.

In order to mount and fix the fastening body of the present invention having such a structure to the curtain rail, the flat plate-shaped fastening body is pressed toward the mounting surface of the curtain rail, and the fitting edge portion is elastic. It is deformed to be folded in two in the width direction, and its double folded end is fitted into the opening of the fitting groove. In order to stabilize the folding back, it is desirable to form one or more concave grooves or uneven surfaces linearly along the folding line. Since the folded edge has a wedge-shaped cross section in any case, it can be easily fitted into the opening of the fitting groove. Moreover, the fitting edge portion that is fitted in the two-folded state from the opening presses the inner wall of the fitting groove portion by the elastic force that tries to restore and is firmly fixed.

Further, in this case, if the thickness of the flat plate-shaped base portion of the fastening body is set to be twice as large as the thickness of the fitting edge portion, preferably approximately 3 times or more, the surface of the flat plate-shaped base portion is projected. At least the curved portion forming the engaging portion with the mating female engaging element of the engaging element to be provided is exposed to the outside from the fitting groove portion of the curtain rail, and particularly the form of the rising portion of the engaging element is exceptional. Without changing the above, it strongly and securely engages and fixes with the loop-shaped engaging element of, for example, the female fastener attached to the upper edge of the curtain.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on illustrated embodiments. FIG. 1 is an exploded perspective view of an essential part showing a mounting state of a fastening member for a sheet material, which is a typical embodiment of the present invention, with respect to a flat plate-shaped mounting body, and FIG. 2 is a perspective view of the fastening member for a sheet material. FIG. 3 is a plan view of the part and a cross-sectional view showing a mounting state of the fastening member for the sheet material to the mounting body.

In these drawings, reference numeral 1 is a sheet material fastening body according to the present embodiment, and reference numeral 2 is a flat plate-shaped mounting body to which the sheet material fastening body 1 is fitted. According to the illustrated example, the flat plate-shaped mounting body 2 is, for example, a curtain rail applied to a curtain device that opens and closes a curtain (not shown) up and down, and extends along both widthwise edges of the long flat plate-shaped mounting portion 2a. L-shaped attachment pieces 2b are integrally extended, and both side edges thereof face each other and have a substantially U-shaped cross section, which constitutes a fitting groove portion 2c of the fastening body 1. Such a structure is substantially the same as the conventional mounting body.

On the other hand, the sheet material fastening body 1 has substantially the same length L as that of the flat plate-shaped mounting body 2 and the width dimension W and the fitting groove portion substantially equal to the distance between the bottom surfaces of the two fitting groove portions 2c. 2c
Has a flat plate-shaped base 3 having a wall thickness T substantially equal to the width dimension of the flat plate-shaped base 3, and the central surface of the flat-plate-shaped base 3 except both end edges (hereinafter, referred to as ears) 3a in the width direction. , Has a large number of hook-shaped engaging elements 4 which are integrally formed with the base portion 3 so as to project. The hook-shaped engaging element 4 has a rising portion 4a that rises from the base portion 3 and a bending portion 4b that extends from the rising portion 4a in the longitudinal direction of the base portion 3 and that has its tip curved toward the base portion 3. Further, according to the illustrated example, a reinforcing rib 4c having a desired height is integrally attached to the side surface of the rising portion 4a. Of course, the form of the hook-shaped engaging element 4 is not limited to the illustrated example,
Further, instead of the hook shape, a male engaging element having a mushroom-shaped or bilobed curved portion may be used.

In the present invention, the width dimension S of the ear portion 3a extending in the width direction from both edges of the flat plate-shaped base portion 3 is set.
However, it has an important meaning that it is set larger than the groove depth D of the fitting groove portion 2c. That is, according to the illustrated example, the ears 3a extend from both edges of the plate-shaped base 3 on the same plane, and the width S of the ears 3a is equal to the width of the mounting body 2.
The fitting groove portion 2c having a U-shaped cross section has a dimension approximately twice the groove depth D.

When the fastening body 1 having the above structure is mounted on the mounting body 2, the fastening body 1 is mounted on the mounting body 2 as shown in FIG.
When pushed from above into the flat plate-shaped mounting portion 2a between the left and right fitting groove portions 2c, the left and right ear portions 3a of the fastening body 1 are fitted in the fitting groove portion 2a.
While being folded in half with the upper end edge of the c on the side of the opening 2d, the edge portion of the ear portion 3a is upwardly folded, the bent end portion is fitted into the slit-shaped opening 2d of the fitting groove portion 2c. Then, the entire ear portion 3a is fitted into the fitting groove portion 2c in a folded state. At this time, the folded piece 3a '
Is trying to return to its original shape inside the fitting groove 2c,
Since the inner wall surface of c is elastically pressed, the fastening body 1 is firmly attached to the mounting body 2.

FIG. 3 shows a modified example of the above-mentioned embodiment. According to this modified example, when the fastening body 1 is mounted on the mounting body 2, the ear portion 3 is provided.
In order to surely bend a along a desired bending line, a groove 3b is formed on the bending line.
The groove 3b may be continuous, but may be an intermittent groove. Further, in the illustrated modification, a plurality of the concave grooves 3b are formed in parallel to facilitate bending with a certain width, but of course, it may be one.

FIG. 4 shows still another modification of the above embodiment. According to this modification, the wall thickness T1 of the tab 3a of the fastening body 1 is set to the wall thickness T2 of the flat base portion 3. About 1/2
And In this way, when the thickness T1 of the ear 3a is set to be smaller than the thickness T2 of the flat plate-shaped base 3, the upper surface of the flat plate-shaped base 3 is located at a position higher than that in the embodiment shown in FIG. As shown in FIG. 4, the upper surface of the flat plate-shaped base portion 3 is substantially equal to the upper end position of the opening 2d of the fitting groove portion 2c, and the curved portion 4b which is at least the engaging portion of the hook-shaped engaging element 4 protruding from the flat plate-shaped base portion 3 is formed. Since it is exposed upward from the upper surface of the mounting body 2, not only can the female hook-and-loop fastener attached along the upper edge of the curtain be reliably engaged with the loop-shaped engaging element, but also the hook can be provided. Since the height of the rising portion 4a of the linear engagement element 4 can be set to the same height as the conventional one, its rigidity is secured and the required engagement strength is maintained. In the present modification, the thickness T of the flat base 3 is
2 does not need to be twice the thickness T1 of the ear portion 3a, and for example, the same thickness T2 of the flat base 3 and the thickness T3 of the mounting body 2
When the wall thickness is set to include the above, all of the hook-shaped engaging elements 4 are exposed from the upper surface of the mounting body 2, and the engagement ratio and the engaging force with the mating female surface fastener are further increased. To increase.

FIG. 5 shows a further modification of the modification shown in FIG. 4 described above, and according to the modification, the thickness T1 is set to be thinner than the thickness T2 of the flat plate-shaped base portion 3. Notches 3c are formed intermittently along the length direction of 3a. This makes it easier for the entire ear 3a to bend,
The fitting operation into the fitting groove portion 2c of the mounting body 2 becomes easier. The size and shape of the notch 3c can be appropriately determined, and are not limited to the illustrated example, and may be, for example, a simple long hole.

FIG. 6 is a cross-sectional view showing a state in which a fastening body 10 showing a typical second embodiment of the present invention is mounted on a flat plate-shaped mounting body 2, and FIG. 7 is a cross-sectional view after completion of the mounting. is there. This embodiment is similar to the above embodiment in that the ears 13a of the fastening body 10 extend along both widthwise edges of the plate-shaped base 13, but substantially half of the ears 13a are provided. Part 13a
-1 does not extend on the same plane as the flat plate-shaped base portion 13, and a hanging piece 13a-2 of substantially the same width stands substantially at a right angle along the half end edge of the extended ear portion 13a. The engaging piece 13a-3 is raised and extends outward from the upper end of the hanging piece 13a-2 at a substantially right angle.

In the fastening body 10 according to the present embodiment having the above-mentioned structure, when the fastening body 10 is pressed against the mounting surface of the flat plate-shaped mounting body 2 in the state shown in FIG. Ear 13
a is elastically deformed by the inner upper edge of the fitting groove portion 2c of the mounting body 2 and crosses the same edge edge, and substantially half portion 13a-of the ear portion 13a-
1 and the hanging piece 13a-2 are deformed into a substantially V shape and fitted into the inside through the opening 2d of the fitting groove portion 2c. When this fitting is completed, as shown in FIG. 7, the engaging piece 13a-3 extending from the upper end of the hanging piece 13a-2 at a substantially right angle is elastically engaged with the upper end edge of the fitting groove opening 2d. To wear. In this manner, in the fastening body 10 mounted on the mounting body 2, the half portion 13a-1 of the ear portion 13a and the hanging piece 13a-2 are fixed by elastically pressing the inner wall surface of the fitting groove portion 2c. Since the engaging piece 13a-3 does not easily come off and is elastically engaged with the upper edge of the fitting groove opening 2d of the mounting body 2, the upper edge is protected from an external impact. To prevent damage to the same edge.

FIG. 8 shows a modification of the second embodiment. Instead of the hanging piece 13a-2 and the engaging piece 13a-3, the half portion 13a-1 of the ear portion 13a extends in the longitudinal direction. The elastic pieces 13a-4 are erected on the protruding side of the hook-shaped engaging element 4 continuously or intermittently along the direction. With this configuration, when the fastening body 10 is attached to the mounting body 2, the elastic piece 13a-4 of the ear portion 13a elastically presses and supports the inner wall of the fitting groove portion 2c of the mounting body 2 as shown in FIG. Therefore, the fastening body 10 is firmly attached to the mounting body 2 as in the second embodiment.

Although not shown in the drawings, in the above-described second embodiment and its modification, as in the modification of the first embodiment (see FIG. 4), the thickness of the flat base portion of the fastening body 10 is the same. The thickness can be set larger than the wall thickness of the ear portion 13a. When the wall thickness of the flat plate-shaped base portion 13 is set larger than the wall thickness of the ear portion in this way, the upper surface of the flat plate-shaped base portion 13 is attached to the mounting body 2 The bending portion 4b which is almost equal to the upper end position of the opening 2d of the fitting groove portion 2c and which projects from the flat plate-shaped base portion 13 and which is at least the engaging portion of the hook-like engaging element 4 is completely upward from the upper surface of the mounting body 2. Since it is exposed, not only the engagement of the surface fastener attached along the edge of the sheet material (not shown) with the female engaging element is ensured, but also the rising of the hook-like engaging element occurs. Since the height of the section can be set to the same height as before, Rigidity is ensured to maintain the required engagement strength.

In each of the above-mentioned embodiments and modifications of the present invention, as the constituent material of the fastening bodies 1 and 10, thermoplastic synthetic resin such as polyamide resin, polyester resin, polypropylene resin can be used, and injection molding can be performed. It is continuously molded by extrusion molding. On the other hand, the flat plate-shaped mounting body 2 is made of a metal material such as aluminum alloy or stainless steel, or various hard synthetic resin materials, and these materials are molded into a shape member having a desired cross-sectional shape by ordinary extrusion.

Now, when the fastening bodies 1, 10 according to the first and second inventions of the present invention are mounted and fixed to the flat plate-shaped mounting body 2 as described above, a large number of hook-shaped engagements of the fastening bodies 1, 10 are achieved. From a large number of loop-shaped engaging elements, which are attached to the male engaging surface of the element 4 by a suitable fixing means such as stitching or adhering to the back end of a sheet material such as carpet, wallpaper or curtain (not shown) A hook-and-loop fastener piece having a female engaging surface is pressed, and the hook-shaped engaging element 4 and the loop-shaped engaging element are engaged and fixed by joining. Here, the engaging element that constitutes the female engaging surface does not necessarily need to be a loop fiber, for example, various hook pieces, a raised fiber of a raised woven or knitted fabric, a nonwoven fabric, and the like,
Various female engaging elements having a structure that can be engaged and disengaged with the male engaging element 4 can be adopted.

[0031]

As is apparent from the above description, according to the fastening body of the present invention, the width of the edge portion of the flat base portion is approximately equal to the depth of the fitting groove portion of the mounting body. And the same ear portion is fitted into the fitting groove portion in a folded state, the folded ear portion is elastically pressed against the inner wall surface of the fitting groove portion to return to the original shape. It becomes possible to firmly mount and fix, and furthermore, mounting of the fastening body to the mounting body can be performed by an extremely simple operation. Further, the fastening body of the present invention having the above-mentioned ear structure has a degree of freedom even when the width of the mounting body is slightly changed, so that the fastening body can be mounted and fixed at all times.

Further, in the present invention, when the flat base is set thicker than the thickness of the ear, the height of the rising portion of the engaging element protruding from the flat base surface is intentionally set to be high. Since the curved portion of the engaging element can be surely projected to the outside from the fitting groove portion of the mounting body without requiring, the surface fastener having the mating female engaging element affixed to the sheet material is surely provided. And it can be joined strongly.

[Brief description of drawings]

FIG. 1 is an exploded perspective view partially showing a structure of a main part of a fastening body and a mounting body thereof as a representative embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a mounting operation and a mounting state of the fastening body.

FIG. 3 is a side view showing a modified example of the fastening body.

FIG. 4 is a sectional view of an essential part showing a mounted state of another modified example of the fastening body.

FIG. 5 is a partial plan view showing still another modified example of the fastening body.

FIG. 6 is a cross-sectional view showing an operating state at the time of mounting the fastening body which is the second embodiment of the present invention.

FIG. 7 is an overall cross-sectional view when the attachment of the fastening body is completed.

FIG. 8 is an overall sectional view of a modified example of the second embodiment when the attachment body is completely attached.

[Explanation of symbols]

 1, 10 Fastening body 2 Mounting body 2a Flat plate-shaped mounting portion 2b Mounting piece 2c Fitting groove portion 2d Opening 3 Flat plate base portion 3a Fitting edge portion (ear portion) 3b Recessed groove 3c Notch 4 (Hook-like) male engagement Element 4a Rising part 4b Curved part 4c Reinforcing rib 13 Flat plate base 13a Ear 13a-1 Half 13a-2 Hanging piece 13a-3 Engagement piece 13a-4 Elastic piece

Claims (7)

[Claims] 1. A mounting body having a fitting groove portion (2c) having a substantially U-shaped cross section in which openings are formed so as to face each other along both edges in the width direction.
A fastening member (1) for a sheet material, which is fitted and fixed in the fitting groove portion (2c) of (2) to join and fix various sheet materials, wherein the fastening member (1) is The fitting groove portions on both edges
(2c) a flat plate-shaped base portion (3) having a fitting edge portion (3a) to be inserted
And a large number of synthetic resin male engaging elements (4) of a surface fastener integrally protruding from one surface between the fitting edge portions (3a) of the flat plate-shaped base portion (3), The edge portion (3a) has a dimension in the width direction sufficient to be fitted and fixed in the fitting groove portion (2c) of the attachment body (2) in a folded state along the length direction in a folded state. A fastening body for a sheet material, which is characterized in that 2. The fastening body according to claim 1, wherein a recessed groove or an uneven surface (3b) is formed along a fold line of the fitting edge portion (3a). 3. The flat plate-shaped base portion (3) in which the fitting edge portion (3a) is formed.
The fastening body according to claim 1, which is in the same plane as, and whose width dimension is larger than the groove depth of the fitting groove portion. 4. The fastening body according to claim 3, wherein the fitting edge portion (3a) has intermittent notches (3c) in the lengthwise direction. 5. A fitting edge portion (1) corresponding to the outside of the fold line.
An approximately half part of 3a) is raised substantially perpendicularly to the projecting side surface of the male engaging element (4), and a tip end of the engaging piece extends outward substantially in parallel with the surface of the flat base. The fastening body according to claim 1, which comprises (13a-3). 6. A substantially vertical portion of the engaging edge portion (13a), which corresponds to the outside of the fold line, extends substantially vertically from the center of the width of a half portion of the fitting edge portion (13a) to the projecting side surface of the engaging element (4). Elastic piece that can be launched (1
The fastening body according to claim 1, which comprises 3a-4). 7. The plate-shaped base portion (3, 13) has a thickness substantially equal to the height dimension of the fitting groove portion (2c), and the fitting edge portion (3a, 3a, 13c).
The fastening body according to any one of claims 2 to 6, wherein the wall thickness of 13a) is smaller than the wall thickness of the flat base portion (3, 13).