JP2006144284A - Rope fastener - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rope fastener easy in fastening to a column. <P>SOLUTION: An inlet part 4 and an outlet part 5 are opened on a side surface on one diameter direction in the vicinity of an upper end part of a column material 3 fitted to a crown part 21 of a column body 2. An inlet side cutout part 41 and an outlet side cutout part 51 opening longitudinally long and formed by cutting out the edge side of an opening recessed part 6 in an inner end side base end part, are arranged in the inlet part 4 and the outlet part 5. A first locking column 71 and a second locking column 72 erected at an interval of a substantially rope diameter in the longitudinal direction of the column material 3, and a rope passage formed around both locking columns 71 and 72 and communicating with the inlet part 4 and the outlet part 5, are arranged in the opening recessed part 6 formed by opening in the sideways direction on a side surface of the column material 3. An inlet side cutout part 41, a locking interval part between the first locking column 71 and the second locking column 72, and an outlet side cutout part 51, are mutually deviated in the longitudinal direction of the column material 3 in a surface including the inlet part 4 and the outlet part 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rope stopper that can be widely used in a wide range of industrial fields such as forestry, fishery, agriculture, construction, etc., and in the leisure field such as establishment of a tent, and is particularly suitable for fixing a rope stretched on a column. Is related to a rope stopper.

  For example, in an afforestation establishment area, a beast damage prevention net is set up to protect seedlings from the damage of ungulates such as deer that eat and destroy young shoots. In other words, by tying the rope that passed through the upper end of the beast harm prevention net to the upper end of the pillars installed at appropriate intervals, the beast harm prevention net was developed to prevent animals from entering the seedling growing area. Yes.

However, the seedling growing area is in a mountainous area and is often inclined, and if the height of the support is low, a sufficient invasion preventing effect cannot be obtained. For this reason, the fixing work of the rope is often performed at an unstable work site, and the work at a high overhead position is forced. Moreover, in order to tie a rope to a support, a skilled technique called “rope work” that handles “wrapping knot” is necessary.
And the above animal damage prevention net is proposed by patent documents 1, for example.

Japanese Utility Model Publication No. 2-120172

  However, in the conventional animal damage prevention net, the work of fixing the rope to the support is troublesome, and a skilled technique is required to stretch the rope while maintaining appropriate tension.

  An object of the present invention is to provide a rope stopper that can be easily fixed to a support column.

The invention according to claim 1 is a rope stopper for tensioning a rope on one end of a support material, and is formed by opening an opening on a side surface of the support material in one diameter direction, An opening recess formed by opening in a direction orthogonal to a surface in the one-diameter direction including the inlet and the outlet, and a first locking column erected in the opening recess with an approximately rope diameter interval; A second locking column, a rope passage formed around the first locking column and the second locking column and communicating with the inlet portion and the outlet portion, are provided at an end of the column member, The rope inserted from the inlet portion is locked to the first locking column and the second locking column along the rope passage in the opening recess, and then pulled out from the outlet portion. .
In the invention according to claim 2, in addition to the configuration of claim 1, the opening recess is opened laterally on the side surface near the end of the support material, and the first locking column and the second locking column are The entrance is formed sideways along the longitudinal direction of the support material, and the inlet portion is formed in the side surface of the support material in a vertically long shape and is formed by cutting out the edge of the opening recess at the base end portion on the inner end side. The outlet portion has a side cutout portion, and has an outlet side cutout portion that is formed by cutting out the edge of the opening concave portion in the base end portion on the outer end side while opening vertically in the side surface of the support material. The entrance-side notch, the locking interval between the first locking column and the second locking column, and the outlet-side notch are long in the plane including the inlet and the outlet. They are offset from each other in the direction.
According to a third aspect of the present invention, in addition to the configuration of the first aspect, the opening recess is opened upward at an upper end portion of the column material, and the first locking column and the second locking column are formed of the column material. The entrance side is erected upward along the diametrical direction, and the entrance portion is formed by opening a laterally long side surface of the upper end portion of the support material and cutting out the edge of the opening recess at the base end portion on one end side. The outlet portion has a laterally open side surface on the upper end portion of the column member, and has an outlet-side notched portion formed by cutting out the edge of the opening recess at the base end portion on the other end side. The inlet-side notch, the locking interval between the first locking column and the second locking column, and the outlet-side notch are strut members on the surface including the inlet and the outlet. Are displaced from each other in the diameter direction.
The invention according to claim 4 includes, in addition to the structure of any one of claims 1 to 3, a fitting hole that can be fitted to one end of the column member, and a plurality of fitting ribs on the inner wall of the fitting hole. Are formed radially.

  The present invention does not require skill, and even a general worker can easily fix the rope to the support column. Moreover, once the rope is laid, it is very difficult to loosen. In addition, because it is easy to work, it can work safely even in unstable work sites, and it does not require a lot of labor for work, so it is less likely to get tired even for long hours of work. .

According to the present invention, a plurality of fitting ribs are radially formed on the inner wall of the fitting hole in the vicinity of the upper end portion of the pillar material having a fitting hole that can be fitted to the top of the column main body, and a side surface in the one-diameter direction. Provided with an inlet part and an outlet part formed by opening the
The entrance portion is provided with an entrance-side notch portion that is vertically elongated on the side surface of the support material and is formed by notching the edge of the opening recess at the proximal end portion on the inner end side. While opening vertically in the side of the material, provided an outlet side cutout formed by cutting out the edge of the opening recess in the base end portion on the outer end side,
An opening recess formed by opening a side surface portion in a direction orthogonal to the one-diameter surface including the inlet portion and the outlet portion, and a spacing between the rope diameters along the longitudinal direction of the support material in the opening recess A first locking column and a second locking column that are erected in a horizontal direction with the door open, and are formed around the first locking column and the second locking column, and communicate with the inlet portion and the outlet portion. A rope passage,
The entrance-side notch, the locking interval between the first locking column and the second locking column, and the outlet-side notch are arranged in the plane including the inlet and the outlet in the longitudinal direction of the column material. Deviate from each other in the direction,
The rope inserted from the inlet portion is locked to the first locking column and the second locking column along the rope passage in the opening recess, and then pulled out from the outlet portion, so that the rope is appropriately fitted. A rope stopper that can be stretched on a column while applying appropriate tension.

1 is a front view of an embodiment of a rope stopper according to the present invention, FIG. 2 is a right side view thereof, FIG. 3 is a left side view thereof, FIG. 4 is a bottom view thereof, and FIG. It is line sectional drawing.
The rope stopper 1 according to the present invention is integrally molded from a thermoplastic synthetic resin such as POM (polyacetal), for example, and in the embodiment shown in the drawings, it is used by being fitted to the top 21 of the column main body 2. It is supposed to be. However, the rope stopper 1 according to the present invention can be formed integrally with the column main body 2.

  The rope stopper 1 shown in the figure is formed of a base portion 11 that is formed in a substantially cylindrical shape and is fitted to the top portion 21 of the column main body 2, and a main body portion 12 that extends to the base portion 11.

  The rope stopper 1 includes an inlet portion 4 and an outlet portion 5 that are formed by opening in the diameter direction of the column material 3 in the vicinity of the end portion of the column material 3 that is the main body portion 12, and the inlet portion 4 and the outlet portion. 5 and an opening recess 6 formed by opening a side portion in a direction orthogonal to the surface of one diameter direction including 5, and a distance of a rope diameter is formed in the opening recess 6 along the longitudinal direction of the support material 3. A first locking column 71 and a second locking member 72 which are erected and formed around the first locking column 71 and the second locking member 72, and the inlet portion 4 and the outlet portion 5. A rope passage 8 communicating therewith.

  Specifically, first, the rope entrance 4 is opened on the side surface of the support material 3. The inlet portion 4 is opened vertically in the longitudinal direction on the side surface of the column member 3. That is, in the drawing, it is formed in the longitudinal direction along the length direction of the support material 3, for example, approximately twice as long as the diameter of the rope, in the longitudinal direction, that is, in the rectangular shape, and the lower half portion is described later. An entrance-side cutout 41 is provided by cutting out the edge of the opening recess 6 to be cut. Therefore, when the entrance portion 4 is viewed from the front, the entrance-side cutout portion 41 is a generally L-shaped opening located on the lower end side (inner end side) of the column member 3 (see FIG. 3). In addition, it is good to chamfer the corner | angular part of the said inlet part 4 suitably, and to provide an inclined part in the corner | angular part of the said inlet part 4 and the inlet side notch part 41. FIG.

  On the other hand, an outlet portion 5 for pulling out the rope is opened on the side surface opposite to the inlet portion 4. The outlet portion 5 is formed in a vertically long rectangle having a length approximately twice the diameter of the rope as in the case of the inlet portion 4, but the outlet side cutout portion 51 communicating with the opening recessed portion 6 is opened. The edge of the recess 6 is cut out, and the outlet side cutout 51 is located on the upper end side (outer end side) of the column member 3. Therefore, when the exit portion 5 is viewed from the front, it is an inverted L-shaped opening (see FIG. 2). In addition, it is good to chamfer the corner | angular part of the said outlet part 5 suitably, and to provide an inclined part in the corner | angular part of the said outlet part 5 and the outlet side notch part 51. FIG.

  An opening recess 6 is formed by opening a side surface in a direction perpendicular to a diametrical surface (hereinafter referred to as a substrate surface) including the inlet portion 4 and the outlet portion 5. And in this opening recessed part 6, the space | interval of a substantially rope diameter is opened along the longitudinal direction of the support | pillar material 3, and the 1st locking pillar 71 and the 2nd locking material 72 of a rectangular prism shape are the said, Stand sideways so as to stand upright with respect to the substrate surface.

  Further, a rope passage 8 having a width of a rope diameter is formed around the first locking pillar 71 and the second locking member 72. In other words, a square-shaped rope passage 8 having a substantially V shape is formed in the opening recess 6, and the rope passage 8 communicates with the inlet portion 4 and the outlet portion 5 described above. And the said entrance part 4, the latching | interval part 81 between the 1st latching pillar 71 and the 2nd latching material 72, ie, the cross | intersection part of the 8-shaped rope path 8, and the said exit part 5 are the following. The support columns 3 are arranged in a straight line in the diameter direction. Furthermore, the entrance-side notch portion 41, the locking interval portion 81, and the exit-side notch portion 51 are displaced in the longitudinal direction of the column member 3, that is, in the vertical direction, on the surface including the entrance portion 4 and the exit portion 5. is doing.

  That is, in other words, the inlet 4 and the inlet-side notch 41, the first locking column 71 and the second locking member 72, the outlet 5 and the outlet-side notch 51 are the first locking column 71. And the second locking member 72 is in a point-symmetrical relationship with the middle point as the center, and the 8-shaped rope passage 8 is also in a point-symmetrical position with the same point as the center.

  On the other hand, in the illustrated embodiment, the base portion 11 for fitting to the top portion 21 of the column main body 2 has a cylindrical shape having an opening at the lower end side and having a fitting hole 13. The column main body 2 is inserted (see FIG. 6). Accordingly, in the embodiment shown in the drawings, fitting ribs 14 that radially expand are provided on the inner wall of the fitting hole 13 (see FIG. 4). For this reason, when the rope stopper 1 is press-fitted into the top 21 of the column main body 2, the fitting rib 14 is deformed so that the fitting with the column main body 2 becomes easy and reliable. The detent is made. A plurality of bosses may be used in place of the fitting rib 14.

Next, how to use the rope stopper 1 according to the present invention will be described.
For example, as shown in FIG. 7, the rope stopper 1 is used in a beast harm prevention net 9 that is installed in order to prevent an animal such as a deer from eating a young sprout in a nursery growing area. This animal damage prevention net 9 is usually attached to a support column 91 installed at an appropriate interval by tying a rope 93 (R) passed through the upper edge of the net 92 and grounding the lower end of the net 92 to the ground. The network 92 is prevented from entering the breeding area.

  Then, although rope 93 (R) is fixed to the support | pillar 91, if the rope stopper 1 which concerns on this invention is used, the fixing operation | work of rope 93 (R) can be performed very easily.

  That is, first, the rope R is inserted into the inlet portion 4 from the inlet-side cutout portion 41 that opens to the opening recess 6. Next, it is bent upward along the rope passage 8, passed through the left side of the first locking column 71 (the same applies hereinafter in FIG. 6), and guided to the upper side of the first locking column 71. Then, it is bent downward and passed through the right side of the first locking column 71, and further folded back to the left side and returned to the inlet 4 side through the locking interval portion 81 between the first locking column 71 and the second locking material 72. .

  Next, the rope R that has returned to the inlet 4 side is bent downward, guided downward through the left side of the second locking member 72, and bent rightward to pass under the second locking member 72. It is bent upward and guided to the outlet portion 5 through the right side of the second locking member 72. And in the exit part 5, it is made to fit in the exit part 5 from the exit side notch part 51, and the rope R is pulled out.

  That is, in the rope stopper 1 according to the present invention, the rope R introduced from the inlet portion 4 is generally “Z” around the first locking pillar 71 and the second locking material 72 along the rope passage 8. It only needs to be drawn out from the outlet 5 through the letter shape.

  And the inlet part 4 and the outlet part 5, the inlet side notch part 41 and the outlet side notch part 51, the first locking pillar 71 and the second locking member 72 are all formed in a rectangular shape, and the rope passage 8 is also angular. Therefore, each corner portion acts on the inserted rope R in a wedge shape to prevent the rope R from loosening.

  In this way, since it is not necessary to draw and tie the long rope R, the animal damage prevention net 9 can be stretched very easily. Therefore, no skill is required, and even regular workers can work reliably. In addition, it is not necessary to route or tie the long rope R (93), and it is not necessary to apply a large force, so that it is possible to work safely even on slopes with poor scaffolding.

  Also, since the height of the column 91 is required to be at least about 1.8 m, an operator having an average height is working near the head, but only two ropes R (93) are used. Therefore, it is possible to work safely and reliably without getting tired.

  Furthermore, if the rope R is introduced from the inlet portion 4 and is locked to the first locking column 71, the tension of the rope R is applied to the first locking column 71, and the subsequent work is against the tension of the rope R. It can be done without any trouble, and the work is easy. On the other hand, if the rope R is pulled in a state where the rope R is locked to the first locking pillar 71, a sufficient tension can be applied to the rope R that is stretched. That is, it is possible to develop the beast damage prevention net 9 without slack.

  FIG. 8 is a perspective view of another embodiment of the rope stopper 1 according to the present invention, FIG. 9 is a left side view thereof, and FIG. 10 is a plan view showing a state in use. This embodiment is different from the above-described embodiment in that the opening recess 6 is opened upward at the upper end portion of the column material 3 and the first support column 71 and the second support column 72 are erected upward. is there. Note that parts having the same functions as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The rope stopper 1 in this embodiment is also integrally formed of, for example, a thermoplastic synthetic resin such as POM (polyacetal). In the embodiment shown in the drawings, the diameter of the upper end portion of the column member 3 is increased to expand the head. Although the portion 15 is provided, it may be formed with the same diameter as the base portion 11, or may be formed integrally with the column main body 2.

  The rope stopper 1 according to the second embodiment has a diameter-enlarged head 15 formed by enlarging the upper end portion of the column member 3 that is the main body portion 12, and a side surface in the one-diameter direction of the diameter-enlarged head 15. An inlet portion 4 and an outlet portion 5 formed by being opened to each other, an opening concave portion 6 formed by opening an upper surface portion in a direction orthogonal to a surface in the diameter direction including the inlet portion 4 and the outlet portion 5, and the opening In the recess 6, a first locking column 71 and a second locking member 72 erected upward along the diametrical direction with a spacing of about a rope diameter, the periphery of the first locking column 71 and the first And a rope passage 8 formed around the two locking members 72 and communicating with the inlet portion 4 and the outlet portion 5.

  That is, the rope entrance 4 is opened on the side surface of the enlarged diameter head 15. This inlet portion 4 is opened horizontally on the side surface of the enlarged diameter head 15. For example, in FIG. 9, it is formed in a horizontally long rectangle in the lateral direction along the side surface of the enlarged diameter head 15, for example, approximately twice as long as the diameter of the rope. Moreover, the half part is notched the edge of the opening recessed part 6, and the entrance side notch part 41 is provided. Therefore, when the entrance 4 is viewed from the front (see the left side in the drawing, see FIG. 9), the entrance-side notch 41 is located at the center of the side surface of the enlarged diameter head 15 and the opening is cut off at the upper edge. It has become.

  On the other hand, an outlet portion 5 for pulling out the rope is opened on the side surface opposite to the inlet portion 4. Like the inlet portion 4, the outlet portion 5 is formed in a rectangular shape that is approximately twice as long as the diameter of the rope. That is, the outlet-side notch 51 that communicates with the opening recess 6 is formed by notching the upper edge of the opening recess 6, and the outlet-side notch 51 is positioned at the center of the side surface of the enlarged diameter head 15. ing.

  In the enlarged diameter head portion 15, an opening concave portion 6 formed by opening an upper surface, which is a diametrical surface including the inlet portion 4 and the outlet portion 5, has an approximately rope diameter interval along the diametrical direction. Thus, the first locking column 71 and the second locking member 72 each having a substantially rectangular column shape are erected upward so as to stand upright.

  Further, a rope passage 8 having a width of a rope diameter is formed around the first locking pillar 71 and the second locking member 72. In other words, a square-shaped rope passage 8 having a substantially V shape is formed in the opening recess 6, and the rope passage 8 communicates with the inlet portion 4 and the outlet portion 5 described above. And the said entrance part 4, the latching | interval part 81 between the 1st latching pillar 71 and the 2nd latching material 72, ie, the cross | intersection part of the 8-shaped rope path 8, and the said exit part 5 are the following. The enlarged heads 15 are arranged in a straight line in the diameter direction. Furthermore, the entrance-side notch 41, the locking interval 81, and the exit-side notch 51 are arranged on the surface including the entrance 4 and the exit 5 in the diameter direction of the column member 3, for example, up and down in FIG. It is deviated in the diametric direction.

  That is, in other words, the inlet 4 and the inlet-side notch 41, the first locking column 71 and the second locking member 72, the outlet 5 and the outlet-side notch 51 are the first locking column 71. And the second locking member 72 is in a point-symmetrical relationship with the middle point as the center, and the 8-shaped rope passage 8 is also in a point-symmetrical position with the same point as the center.

  In the description of the second embodiment described above, the opening recessed portion 6 is formed in the enlarged diameter head 15 formed by expanding the upper end portion of the column member 3 that is the main body portion 12, and the inside of the opening recessed portion 6. The first locking column 71 and the second locking member 72 are erected, but may be formed directly on the support column 3 without forming the enlarged diameter head 15. What is necessary is just to set this suitably from the relationship between the diameter of the rope to be used, and the diameter of the support | pillar material 3, etc.

  The usage of the rope stopper 1 according to the second embodiment as described above is the same as that of the first embodiment. That is, as shown in FIG. 10, the rope R is inserted into the inlet portion 4 from the inlet-side cutout portion 41 that opens to the opening recess 6. Next, it is bent upward along the rope passage 8, passed through the left side of the first locking column 71, and guided to the upper side of the first locking column 71. Then, it is bent downward and passed through the right side of the first locking column 71, and further folded back to the left side and returned to the inlet 4 side through the locking interval portion 81 between the first locking column 71 and the second locking material 72. .

  Next, the rope R that has returned to the inlet 4 side is bent downward, guided downward through the left side of the second locking member 72, and bent rightward to pass under the second locking member 72. It is bent upward and guided to the outlet portion 5 through the right side of the second locking member 72. And in the exit part 5, the rope R should just be pulled out by making it fit in the exit part 5 from the exit side notch part 51. FIG.

  The rope stopper 1 according to the second embodiment also includes an inlet portion 4 and an outlet portion 5, an inlet side cutout portion 41 and an outlet side cutout portion 51, a first locking post 71, and a second locking member 72. Since the rope passage 8 is formed in a rectangular shape and has an angular shape, each of the corner portions acts like a wedge on the inserted rope R to prevent the rope R from loosening.

  And since the rope stopper 1 by the 2nd Example does not need to draw and tie the long rope R, even the general worker who does not have a skill can work reliably. In addition, the rope stopper 1 according to the second embodiment is preferably used at a site where a rope is stretched at a relatively low position where the work can be performed while visually observing from above.

  Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to the above-described embodiment, and can be appropriately implemented without changing the configuration described in the claims. For example, in the above-described embodiment, the rope stopper 1 fitted to the top 21 of the column main body 2 is shown. However, the rope stopper 1 may be formed integrally with the column main body 2. In addition, the method of locking the rope R with respect to the locking pillars 71 and 72 is not limited to “Z” -shaped, but can be “S” -shaped, “8” -shaped, etc. It may be locked to.

  Moreover, although the above-mentioned Example demonstrated the beast harm prevention net | network 9 in forestry, the rope stopper 1 of this invention can be utilized for many fields. For example, it can be applied to installation of a laver shelf for cultivating seaweed in the fishery industry, or a rope can be stretched on the seabed to grow algae and use it for the formation of a fish reef. Even in these cases, it is possible to reliably and safely work on board or underwater work where it is difficult to apply power. It can also be used as a branch line for vines in agriculture, or for setting up a greenhouse.

It is a front view by the 1st Example of the rope stopper which concerns on this invention. It is a right view by the 1st Example of the rope stopper which concerns on this invention. It is a left view by the 1st Example of the rope stopper which concerns on this invention. It is a bottom view by the 1st Example of the rope stopper which concerns on this invention. It is the sectional view on the AA line in FIG. It is front explanatory drawing of the state which has fitted and used the rope stopper which concerns on this invention to the top part of the support | pillar main body. It is a perspective view which shows the state which uses the rope stopper which concerns on this invention for a beast harm prevention net. It is a perspective view by the 2nd Example of the rope stopper which concerns on this invention. It is a left side surface by the 2nd Example of the rope stopper which concerns on this invention. It is a top view by the 2nd Example of the rope stopper which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rope stopper 2 Support | pillar main body 3 Support | pillar material 4 Inlet part 5 Outlet part 6 Opening recessed part 8 Rope passage 9 Beast damage prevention net 11 Base part 12 Main body part 13 Insertion hole 14 Insertion rib 15 Expanded head 21 Head top 41 Inlet-side notch 51 Exit-side notch 71 First locking column 72 Second locking material 81 Locking interval 91 Strut 92 Beast damage prevention net 93 Rope R rope

Claims (4)

A rope stopper for tensioning a rope on one end of a support material,
An inlet portion and an outlet portion formed by opening on one side in the diameter direction of the strut material;
An opening recess formed by opening in a direction perpendicular to the one-diameter surface including the inlet portion and the outlet portion;
A first locking column and a second locking column which are erected in the opening recess with an approximately rope diameter interval;
A rope passage formed around the first locking column and the second locking column and communicating with the inlet and the outlet;
At the end of the strut material,
The rope inserted from the inlet portion is locked to the first locking column and the second locking column along the rope path in the opening recess, and then pulled out from the outlet portion. Rope stopper to do. The opening recess is opened sideways on the side surface near the end of the support material,
The first locking column and the second locking column are erected sideways along the longitudinal direction of the column material,
The entrance portion has an entrance-side cutout portion that is formed by cutting out the edge of the opening recess in the base end portion on the inner end side while opening vertically in the side surface of the support material.
The outlet portion has an outlet-side cutout portion that is formed by cutting out the edge of the opening concave portion at the base end portion on the outer end side while opening vertically in the side surface of the support material.
The entrance-side notch, the locking interval between the first locking column and the second locking column, and the outlet-side notch are long in the plane including the inlet and the outlet. The rope stop according to claim 1, wherein the rope stops are offset from each other in the direction. The opening recess is opened upward at the upper end of the support material,
The first locking column and the second locking column are erected upward along the diameter direction of the column material,
The inlet portion has an inlet-side cutout portion formed by opening the side surface of the upper end portion of the support material in a horizontally long shape and cutting out the edge of the opening recess in the base end portion on one end side.
The outlet portion has an outlet side cutout portion that is formed by cutting out the edge of the opening recess in the base end portion on the other end side while opening horizontally on the side surface of the upper end portion of the support material,
The diameter of the strut material on the surface including the inlet portion and the outlet portion, wherein the inlet side notch portion, the locking interval portion between the first locking column and the second locking column, and the outlet side notch portion are included. The rope stop according to claim 1, wherein the rope stops are offset from each other in the direction. The rope stopper according to any one of claims 1 to 3, further comprising: a fitting hole that can be fitted to one end portion of the support material; and a plurality of fitting ribs formed radially on the inner wall of the fitting hole.

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