JPH0942248A - Rivet made of fiber-reinforced resin - Google Patents
Rivet made of fiber-reinforced resinInfo
- Publication number
- JPH0942248A JPH0942248A JP19339695A JP19339695A JPH0942248A JP H0942248 A JPH0942248 A JP H0942248A JP 19339695 A JP19339695 A JP 19339695A JP 19339695 A JP19339695 A JP 19339695A JP H0942248 A JPH0942248 A JP H0942248A
- Authority
- JP
- Japan
- Prior art keywords
- fiber
- reinforced resin
- cured
- end side
- rivet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Insertion Pins And Rivets (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、繊維強化樹脂製リ
ベットに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforced resin rivet.
【0002】[0002]
【従来の技術】従来、被締結物を締結にする際に使用さ
れるリベットとしては、金属製リベットが広く市販、使
用されている。しかし、金属製リベットは、材料が硬い
ため作業性が悪く、足場の悪い施工現場での作業は危険
であり、又、一般に高価である。2. Description of the Related Art Heretofore, metal rivets have been widely marketed and used as rivets used for fastening objects to be fastened. However, the metal rivet has a poor workability because the material is hard, and it is dangerous to work at a construction site where the scaffolding is poor, and it is generally expensive.
【0003】この点に鑑み、例えば、特公昭63─11
523号公報に記載の如く、一端に半径方向に大きい金
床部と他端に掴み部とを持つ細長い心棒と、心棒のまわ
りに置かれたスリーブと、このスリーブと心棒の間に置
かれた未硬化の熱硬化製プラスチックの筒状体とからな
り、片方から締結作業ができる盲リベットが提案されて
いる。In view of this point, for example, Japanese Examined Patent Publication No. 63-11
As described in Japanese Patent No. 523,523, an elongated mandrel having a large anvil part at one end and a grip part at the other end, a sleeve placed around the mandrel, and a sleeve placed between the sleeve and the mandrel. A blind rivet has been proposed which is composed of an uncured thermosetting plastic tubular body and can be fastened from one side.
【0004】[0004]
【発明が解決しようとする課題】しかしながら、この盲
リベットは、半径方向に大きい金床部を持ったスリー
ブ、心棒及び筒状体という3部品から構成されており、
その製作が別々の工程を要するので煩雑であるととも
に、大きな締結強度が得られない。又、半径方向に大き
な金床部を持ったスリーブと変形部とが一体となったプ
ラスチック部品としては未硬化熱硬化性樹脂部品が考え
られるが、現実問題として、硬化部と未硬化部とを熱の
コントロールだけで保持するのは難しいという問題点が
ある。However, this blind rivet is composed of three parts, a sleeve having a large anvil part in the radial direction, a mandrel and a tubular body,
Since the production requires separate steps, it is complicated and a large fastening strength cannot be obtained. Further, an uncured thermosetting resin part may be considered as a plastic part in which a sleeve having a large anvil part in the radial direction and a deformed part are integrated, but as a practical problem, the cured part and the uncured part are separated. There is a problem that it is difficult to hold it only by controlling heat.
【0005】本発明は、上記の如き従来の問題点を解消
することを目的としてなされたものであって、締結作業
性が優れた変形しやすい部分を有し、耐蝕性と締結強度
に優れた締結を行うことができる繊維強化樹脂製リベッ
トを提供することを目的としてなされたものである。The present invention has been made for the purpose of solving the above-mentioned conventional problems, and has a portion that is easily deformed and has excellent fastening workability, and is excellent in corrosion resistance and fastening strength. The purpose of the present invention is to provide a fiber-reinforced resin rivet that can be fastened.
【0006】[0006]
【課題を解決するための手段】本発明は、柱状部の一端
に頭部が設けられた繊維強化樹脂製リベットであって、
繊維強化樹脂製リベットを形成する繊維強化樹脂が樹脂
成分中に繊維含有率20〜70重量%にて長繊維を含有
するものからなり、長手方向に沿って長繊維が多数配列
された柱状部の一端側とその一端に設けられた頭部とが
一体的に完全硬化され、柱状部の他端側の少なくとも一
定長が未硬化乃至半硬化状態とされ、被締結物の締結時
に他端側の未硬化乃至半硬化状態の部分を変形後、完全
硬化可能とされている繊維強化樹脂製リベットである。DISCLOSURE OF THE INVENTION The present invention is a fiber-reinforced resin rivet having a head portion at one end of a columnar portion,
The fiber reinforced resin forming the fiber reinforced resin rivet is composed of a resin component containing long fibers at a fiber content of 20 to 70% by weight, and has a columnar section in which a large number of long fibers are arranged along the longitudinal direction. The one end side and the head provided at the one end thereof are completely hardened integrally, and at least a certain length of the other end side of the columnar portion is in an uncured or semi-hardened state, and the other end side is fastened at the time of fastening an object to be fastened. It is a fiber-reinforced resin rivet that can be completely cured after deformation of an uncured or semi-cured portion.
【0007】本発明において、繊維強化樹脂を形成する
樹脂成分としては、硬化性樹脂が使用され、例えば、不
飽和ポリエステル樹脂、ビニルエステル(エポキシアク
リレート)樹脂、ウレタンアクリレート樹脂等が挙げら
れる。硬化性樹脂は、単独で使用されてもよいし、複数
種混合して使用されてもよい。In the present invention, a curable resin is used as the resin component forming the fiber reinforced resin, and examples thereof include unsaturated polyester resin, vinyl ester (epoxy acrylate) resin and urethane acrylate resin. The curable resin may be used alone or in combination of two or more.
【0008】硬化性樹脂中には、硬化剤と、必要に応じ
て、充填剤、禁止剤、顔料、低収縮剤、離型剤、増粘剤
等の添加剤が添加される。硬化剤としては、熱硬化剤や
光開始剤が使用される。熱硬化剤としては、従来公知の
ものを使用することができ、例えば、メチルエ4ルケト
ンパーオキサイド、t─ブチルパーベンゾエート、ベン
ゾイルパーオキサイド等が挙げられ、ナフテン酸コバル
ト、ナフテン酸マンガン、ジメチルアニリン等の硬化促
進剤が併用されてもよい。In the curable resin, a curing agent and, if necessary, additives such as a filler, an inhibitor, a pigment, a low-shrinking agent, a release agent and a thickener are added. A thermosetting agent or a photoinitiator is used as the curing agent. As the thermosetting agent, conventionally known ones can be used, and examples thereof include methyl ethyl ketone peroxide, t-butyl perbenzoate, benzoyl peroxide, and the like. Cobalt naphthenate, manganese naphthenate, dimethylaniline. A curing accelerator such as the above may be used in combination.
【0009】光開始剤としては、従来公知のものを使用
することができ、例えば、ベンゾインアルキルエーテル
系、アセトフェノン系、ベンゾフェノン系、チオキサン
ソン系等が挙げられる。As the photoinitiator, conventionally known photoinitiators can be used, and examples thereof include benzoin alkyl ether type, acetophenone type, benzophenone type and thioxanthone type.
【0010】本発明において、上記の硬化剤は、単独で
使用されてもよいし、2種類以上併用されてもよい。熱
硬化剤と光開始剤とを併用して、未硬化乃至半硬化状態
の部分の熱硬化及び光硬化のいずれも可能としておけ
ば、繊維強化樹脂製リベットの締結現場の締結作業のし
易さに応じていずれの硬化方法をも採用することができ
るので便利である。In the present invention, the above curing agents may be used alone or in combination of two or more kinds. If both the uncured and semi-cured parts can be heat-cured and light-cured by using a heat-curing agent and a photoinitiator together, the ease of fastening work at the fastening site of fiber-reinforced resin rivets It is convenient because any curing method can be adopted according to the above.
【0011】本発明において、繊維強化樹脂を形成する
長繊維の材質としては、例えば、ガラス繊維、カーボン
繊維等の無機繊維、アラミド繊維、ビニロン繊維、ポリ
エステル繊維等の有機繊維などが挙げられる。長繊維の
形態としては、例えば、モノフィラメント、ロービング
状、ストランド状、クロス状、マット状、網状、ネット
状等が挙げられ、連続繊維からなるコンティニュアスス
トランドマットであってもよい。In the present invention, examples of the material of the long fibers forming the fiber reinforced resin include inorganic fibers such as glass fibers and carbon fibers, organic fibers such as aramid fibers, vinylon fibers and polyester fibers. Examples of the form of the long fiber include a monofilament, a roving form, a strand form, a cross form, a mat form, a net form, and a net form, and a continuous strand mat made of continuous fibers may be used.
【0012】繊維強化樹脂中の長繊維の繊維含有量とし
ては、20〜70重量%とされる。繊維含有量が少なす
ぎると、長繊維による補強効果が少なく、多すぎると、
樹脂成分が少なくなるので、長繊維のフィラメント間の
接着力が弱く、いずれも得られる繊維強化樹脂製リベッ
トが締結強度が十分でない。The fiber content of the long fibers in the fiber reinforced resin is 20 to 70% by weight. If the fiber content is too low, the reinforcing effect due to the long fibers is small, and if the fiber content is too high,
Since the resin component is reduced, the adhesive force between filaments of long fibers is weak, and the rivets made of fiber reinforced resin obtained in both cases have insufficient fastening strength.
【0013】本発明において、柱状部の他端側の少なく
とも一定長における未硬化状態とは、未だ完全硬化され
ていない状態をいい、未硬化状態と半硬化状態とを含む
概念であり、保管中、運搬中に自重や他の部材との接触
により容易に変形しないような半硬化状態とされている
のが好ましい。In the present invention, the uncured state in at least a fixed length on the other end side of the columnar portion means a state in which the column is not completely cured yet, and is a concept including an uncured state and a semi-cured state, which is being stored. The semi-cured state is preferably such that it is not easily deformed due to its own weight or contact with other members during transportation.
【0014】[0014]
【発明の実施の形態】以下、本発明を図面を参照して説
明する。図1は本発明の繊維強化樹脂製リベットの一例
を示す正面図である。1は繊維強化樹脂製リベットであ
って、長繊維に熱硬化剤及び光開始剤の一方又は両方を
含有する硬化性樹脂が含浸され、繊維含有量が20〜7
0重量%とされた繊維強化樹脂から製せられており、柱
状部11の一端に頭部12が設けられている。柱状部1
1には、硬化性樹脂中に長手方向に沿って配向するよう
に長繊維が連続的に配設されている。DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings. FIG. 1 is a front view showing an example of a fiber-reinforced resin rivet of the present invention. Reference numeral 1 denotes a fiber-reinforced resin rivet, in which long fibers are impregnated with a curable resin containing one or both of a thermosetting agent and a photoinitiator, and a fiber content of 20 to 7
It is made of 0% by weight of fiber reinforced resin, and a head 12 is provided at one end of the columnar part 11. Column 1
In Fig. 1, long fibers are continuously arranged in the curable resin so as to be oriented along the longitudinal direction.
【0015】柱状部11の一端側111とその一端に設
けられた頭部12とが一体的に完全硬化されている。柱
状部11の他端側112は、他端縁を残して未硬化乃至
半硬化状態とされ、他端縁は完全硬化されている。そし
て、被締結物の締結時に他端側の一定長にわたる未硬化
乃至半硬化状態の部分を変形後、硬化可能とされてい
る。柱状部11の未硬化乃至半硬化状態とされている部
分を含む他端側112の周りには、光線を遮断して硬化
剤が分解して硬化反応が開始しないようにアルミホイル
2が巻き付けられている。One end side 111 of the columnar portion 11 and the head portion 12 provided at one end thereof are integrally and completely cured. The other end side 112 of the columnar portion 11 is in an uncured or semi-cured state, leaving the other end edge, and the other end edge is completely hardened. When the object to be fastened is fastened, the part in the uncured or semi-cured state over a certain length on the other end side can be deformed and then cured. The aluminum foil 2 is wound around the other end 112 including the uncured or semi-cured portion of the columnar portion 11 so that the curing agent is not decomposed by blocking light rays and the curing reaction is not started. ing.
【0016】次に、図1の繊維強化樹脂製リベットの使
用態様を、図2及び図3を参照して説明する。図2に示
す如く、3,4は本発明の繊維強化樹脂製リベットによ
り締結される2つの被締結物であって、それぞれに設け
られた貫通孔31,41が通じるように重ね合わされて
いる。Next, the manner of use of the fiber reinforced resin rivet of FIG. 1 will be described with reference to FIGS. As shown in FIG. 2, 3 and 4 are two objects to be fastened by the fiber-reinforced resin rivet of the present invention, and they are superposed so that the through holes 31 and 41 provided in them respectively communicate with each other.
【0017】まず、繊維強化樹脂製リベット1の柱状部
11の他端部の周りに巻き付けられたアルミホイル2を
剥がし、その繊維強化樹脂製リベット1を他端側112
より、被締結物3,4の貫通孔31,41に挿通し、反
対側の他端に設けられた頭部12を被締結部3の貫通孔
31の周りの壁部の端面に当接させる。First, the aluminum foil 2 wrapped around the other end of the columnar portion 11 of the fiber reinforced resin rivet 1 is peeled off, and the fiber reinforced resin rivet 1 is attached to the other end side 112.
Thus, the head 12 provided at the other end on the opposite side is inserted into the through holes 31 and 41 of the objects to be fastened 3 and 4, and is brought into contact with the end surface of the wall portion around the through hole 31 of the fastened portion 3. .
【0018】次に、図3に示す如く、繊維強化樹脂製リ
ベット1の頭部12を被締結物3の壁面に押圧した状態
にて、その他端側112の他端縁から圧縮して、他端側
112の未硬化乃至半硬化状態の部分を膨出させる。そ
の状態のままに保持しつつ、その未硬化乃至半硬化状態
の部分を熱硬化乃至光硬化させることにより完全硬化さ
せて、被締結物の締結を終了する。Next, as shown in FIG. 3, while the head 12 of the fiber reinforced resin rivet 1 is pressed against the wall surface of the object to be fastened 3, it is compressed from the other end edge of the other end side 112 and The uncured or semi-cured portion of the end side 112 is swollen. While maintaining that state, the uncured or semi-cured portion is completely cured by thermosetting or photocuring, and the fastening of the object to be fastened is completed.
【0019】[0019]
【作用】本発明の繊維強化樹脂製リベットは、繊維強化
樹脂製リベットを形成する繊維強化樹脂が樹脂中に繊維
含有率20〜70重量%にて長繊維を含有するものから
なり、長手方向に沿って長繊維が多数配列された柱状部
の一端側とその一端に設けられた頭部とが一体的に完全
硬化され、柱状部の他端側の少なくとも一定長が未硬化
乃至半硬化状態とされ、被締結物の締結時に他端側の未
硬化乃至半硬化状態の部分を変形後、完全硬化可能とさ
れていることにより、被締結物の締結時に、他端側の未
硬化乃至半硬化状態の部分を変形後、完全硬化させるよ
うにして簡単の締結できるので、締結作業性が優れてお
り、又、耐蝕性と強度が十分な繊維強化樹脂材料からな
るので、耐久性及び締結強度に優れた締結を行うことが
できる。The fiber-reinforced resin rivet of the present invention comprises the fiber-reinforced resin forming the fiber-reinforced resin rivet containing long fibers at a fiber content of 20 to 70% by weight in the resin. One end side of the columnar section along which a number of long fibers are arranged along with the head provided at the one end are completely cured integrally, and at least a certain length on the other end side of the columnar section is in an uncured or semi-cured state. The uncured or semi-cured part on the other end side is deformed at the time of fastening the object to be fastened and then completely hardened. It can be easily fastened by completely hardening it after deformation of the part in the state, so it has excellent fastening workability.Because it is made of a fiber reinforced resin material with sufficient corrosion resistance and strength, it has excellent durability and fastening strength. Excellent fastening can be performed.
【0020】[0020]
【実施例】以下、本発明を実施例により説明する。実施例1 硬化性樹脂として、不飽和ポリエステル樹脂(日本ユピ
カ社製、商品名「4516」)100重量部と、熱硬化
剤(チバガイギー社製、商品名「イルガキュア65
1」)1.5重量部からなるものを用い、これにガラス
ロービングを含浸させて、繊維含有量45重量%の繊維
強化樹脂材料を作製した。The present invention will be described below with reference to examples. Example 1 As a curable resin, 100 parts by weight of an unsaturated polyester resin (manufactured by Japan Yupica, trade name "4516") and a thermosetting agent (manufactured by Ciba Geigy, trade name "Irgacure 65"
1 ") 1.5 parts by weight was used and impregnated with glass roving to prepare a fiber reinforced resin material having a fiber content of 45% by weight.
【0021】この繊維強化樹脂材料を用いて、プレス成
形により、図1に示すような、柱状部11の一端側11
1とその一端に設けられた頭部12とが一体的に完全硬
化され、柱状部11の他端側112は他端縁を残して未
硬化状態とされ、他端は完全硬化されている繊維強化樹
脂製リベット1を製造した。By using this fiber-reinforced resin material, press molding is carried out, and one end side 11 of the columnar part 11 as shown in FIG.
1 and a head 12 provided at one end thereof are completely hardened integrally, the other end side 112 of the columnar portion 11 is in an uncured state leaving the other end edge, and the other end is completely hardened. A reinforced resin rivet 1 was manufactured.
【0022】この繊維強化樹脂製リベット1を用いて、
図2及び図3を参照して説明したように、他端側11よ
り、角材とプレートの組合わせからなる被締結物3,4
の貫通孔31,41に挿通し、その一端に設けられた頭
部12を被締結部3の貫通孔31の周りの壁面に当接さ
せ、押圧状態してその他端縁から圧縮して、他端側の未
硬化状態の部分を膨出させ、その状態のままに保持しつ
つ、その未硬化状態の部分を熱硬化させることにより完
全硬化させて、被締結物を締結することができた。Using this fiber-reinforced resin rivet 1,
As described with reference to FIGS. 2 and 3, from the other end side 11, the objects to be fastened 3, 4 made of a combination of a square bar and a plate.
Through the through-holes 31 and 41, and the head 12 provided at one end thereof is brought into contact with the wall surface around the through-hole 31 of the fastened portion 3, pressed and compressed from the other edge, and the like. It was possible to swell the uncured portion on the end side and hold the uncured portion in that state, while the uncured portion was heat-cured to be completely cured and to fasten the object to be fastened.
【0023】[0023]
【発明の効果】本発明の繊維強化樹脂製リベットは、上
記の如き構成とされているので、締結作業性が優れてお
り、又、耐久性及び締結強度に優れた締結を行うことが
できる。The fiber-reinforced resin rivet according to the present invention, which has the above-mentioned structure, has excellent fastening workability and can be fastened with excellent durability and fastening strength.
【図1】本発明の繊維強化樹脂製リベットの一例を示す
一部切欠き正面図である。FIG. 1 is a partially cutaway front view showing an example of a fiber-reinforced resin rivet of the present invention.
【図2】図1に示す繊維強化樹脂製リベットの使用態様
の前半の工程を示す断面図である。FIG. 2 is a cross-sectional view showing the first half of the process of using the fiber-reinforced resin rivet shown in FIG.
【図3】図1に示す繊維強化樹脂製リベットの使用態様
の後半の工程を示す断面図である。FIG. 3 is a cross-sectional view showing a latter half step of the usage mode of the fiber-reinforced resin rivet shown in FIG.
1 繊維強化樹脂製リベット 11 柱状部 12 頭部 111 一端側 112 他端側 1 Fiber Reinforced Resin Rivet 11 Columnar Part 12 Head 111 One End Side 112 The Other End Side
Claims (1)
化樹脂製リベットであって、繊維強化樹脂製リベットを
形成する繊維強化樹脂が樹脂成分中に繊維含有率20〜
70重量%にて長繊維を含有するものからなり、長手方
向に沿って長繊維が多数配列された柱状部の一端側とそ
の一端に設けられた頭部とが一体的に完全硬化され、柱
状部の他端側の少なくとも一定長が未硬化乃至半硬化状
態とされ、被締結物の締結時に他端側の未硬化乃至半硬
化状態の部分を変形後、完全硬化可能とされていること
を特徴とする繊維強化樹脂製リベット。1. A fiber reinforced resin rivet in which a head is provided at one end of a columnar portion, wherein the fiber reinforced resin forming the fiber reinforced resin rivet has a fiber content of 20 to 20 in the resin component.
70% by weight of long fibers are contained, and one end side of a columnar portion in which a large number of long fibers are arranged along the longitudinal direction and a head provided at the one end are integrally completely cured to form a columnar shape. At least a certain length on the other end side of the portion is in an uncured or semi-cured state, and at the time of fastening an object to be fastened, the portion in the uncured or semi-cured state on the other end side is deformed and then completely cured. Characteristic fiber reinforced resin rivet.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP19339695A JPH0942248A (en) | 1995-07-28 | 1995-07-28 | Rivet made of fiber-reinforced resin |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP19339695A JPH0942248A (en) | 1995-07-28 | 1995-07-28 | Rivet made of fiber-reinforced resin |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0942248A true JPH0942248A (en) | 1997-02-10 |
Family
ID=16307257
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP19339695A Pending JPH0942248A (en) | 1995-07-28 | 1995-07-28 | Rivet made of fiber-reinforced resin |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0942248A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005042538A (en) * | 2004-07-20 | 2005-02-17 | Toshio Kamata | U-shaped ditch |
JP2016050660A (en) * | 2014-09-02 | 2016-04-11 | 三菱電機株式会社 | Fixing method of body of revolution and winch for elevator |
-
1995
- 1995-07-28 JP JP19339695A patent/JPH0942248A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005042538A (en) * | 2004-07-20 | 2005-02-17 | Toshio Kamata | U-shaped ditch |
JP2016050660A (en) * | 2014-09-02 | 2016-04-11 | 三菱電機株式会社 | Fixing method of body of revolution and winch for elevator |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6316074B1 (en) | Reinforced composite product and apparatus and method for producing same | |
JP4969717B2 (en) | Manufacturing method of composite parts subjected to strong stress | |
US6352662B1 (en) | Integral molded grip and shaft | |
EP0690936A1 (en) | Aligned fiber reinforcement panel for wood members | |
JPH03500665A (en) | Fiber/resin composite material and its manufacturing method | |
EP0673752A1 (en) | Pipe or hollow profile having particular strength characteristics with a low weight, and method for making it | |
JP2010149350A (en) | Composite member and method of manufacturing thereof | |
JPH0942248A (en) | Rivet made of fiber-reinforced resin | |
JP3045659B2 (en) | Golf club shaft and method of manufacturing the same | |
JPH0561091B2 (en) | ||
JP2826742B2 (en) | Reinforcement method of building using fiber reinforced plastic plate | |
US5804012A (en) | Process for manufacturing a filament wound, localized strength tool handle | |
JP3327984B2 (en) | Method for producing fiber-reinforced resin shaped rods | |
JP3142394B2 (en) | Reinforced plastic pipe and method of manufacturing the same | |
EP0292703A2 (en) | Process and device for laying plastic pipes | |
JP2004131985A (en) | Reinforcing prepreg sheet and the reinforcing method of concrete construction | |
JP2005097854A (en) | Reinforcing construction method of steel structure | |
JPH06193281A (en) | Concrete repairing method with unidirectionally arranged fiber-reinforced sheet | |
JPH05138743A (en) | Lightweight structural body and structure of connection part thereof | |
JPH05302400A (en) | Fiber reinforced structural member | |
JPH06166110A (en) | Stick-like article made of fiber reinforced resin | |
JPH08209692A (en) | Reinforcement material for earth anchor construction method and its manufacture and usage | |
JP2024061005A (en) | Fiber reinforced resin filament | |
JPH1076034A (en) | Method for forming display portion of golf club shaft | |
JPH08158664A (en) | Structure reinforcing method |