JP3811916B2

JP3811916B2 - Manhole cover structure

Info

Publication number: JP3811916B2
Application number: JP2002134318A
Authority: JP
Inventors: 俊哉山下; 晃知岸本
Original assignee: 株式会社ヨドキャスチング
Priority date: 2002-05-09
Filing date: 2002-05-09
Publication date: 2006-08-23
Anticipated expiration: 2022-05-09
Also published as: JP2003328379A

Description

【０００１】
【発明の属する技術分野】
本発明は、閉蓋ロック機構が設けてあるマンホール蓋構造に関する。
【０００２】
【従来の技術】
この種のマンホール蓋構造としては、例えば特開平９−２９６４７０号公報にみることができる。そこでは、マンホール蓋の下面側に、三角状の錠止金具を軸まわりに揺動自在に吊り下げ、そのマンホール蓋の下面対向位置にヒンジ金具を配置している。
【０００３】
そして、錠止金具をこれの自重で、マンホール蓋が嵌め込まれる受枠に設けた係合部に係合させることにより、マンホール蓋が上方移動可能に、しかし抜け外れは不能に係合案内されて、集中豪雨の際の異常な揚水圧やマンホール内で発生するガス圧などがマンホール蓋に加わっても、マンホール蓋が上昇変位してマンホール内に充満する流水やガスを放出して、マンホールの内圧を解放するようにしている。
【０００４】
かかるマンホール蓋を開ける場合には、マンホール蓋のキー孔にベルクランク形のキーを挿入して、錠止金具の頭部を押圧し、錠止金具をこれの自重に抗して解除方向に揺動させて、受枠の係合部との係合状態を解除する。この状態で、キーを軸心まわりに９０度回動させて、キーの先端部をキー孔の内部に上方へ抜け止め状に係合し、このままキーを持ち上げて蓋全体が上下反転状になるまで揺動させるか、あるいはキーでマンホール蓋を持ち上げた姿勢のままヒンジ金具を中心に蓋全体を水平方向へ１８０度旋回させることで、マンホール蓋を全開するようになっている。
【０００５】
【発明が解決しようとする課題】
マンホール蓋は、球状黒鉛鋳鉄（ＦＣＤ）などで形成されて重量が大きくなっているため、前述のようにマンホール蓋を上下反転状になるまで揺動させることは容易ではない。また、前記マンホール蓋を水平方向へ旋回させる場合でも、錠止金具がマンホール蓋の下面側に吊り下がっているため、錠止金具が受枠よりも高くなるまでマンホール蓋を持ち上げる必要があり、その分だけ作業者に負担が掛かる。
【０００６】
そこで本発明の目的は、このような実情に着目してなされたものであって、マンホールの内圧を解放できながら、マンホール蓋の持ち上げ量が少なくてもマンホール蓋を全開できるようにして作業者の負担を軽減できるマンホール蓋構造を提供することにある。
【０００７】
【課題を解決するための手段】
本発明のマンホール蓋構造は、図１に示すごとく、環状の受枠２と、その受枠２に対して着脱自在に嵌め込み装着されるマンホール蓋４とを備えており、マンホール蓋４と受枠２との間に、内圧解放機能を有する閉蓋ロック機構が設けてある。閉蓋ロック機構は、マンホール蓋４と受枠２との間に設けられた凹凸係合構造１０と錠止構造１３とで構成されており、凹凸係合構造１０と錠止構造１３とが、マンホール蓋４の径方向に対向する位相位置にそれぞれ配置されている。凹凸係合構造１０は、マンホール蓋４と受枠２との間で横向きに凹凸係合する接合突起８と接合凹部９とを備えており、接合突起８と接合凹部９との間には、内圧解放時のマンホール蓋４の浮上を許すための浮上隙間Ｅが設けられている。錠止構造１３は、マンホール蓋４と受枠２との間で横向きに係合するラッチ１４と受け凹部１５とを備えている。ラッチ１４は、受け凹部１５に向けて開口する凹所１９の内部に収容されて、ラッチ１４の先端部１４ａが受け凹部１５に対し係脱移動自在になっているとともに、その凹所１９の内部に収容されたばね部材２４で受け凹部１５側へ付勢されている。マンホール蓋４の上面の外周寄り部位に、ラッチ１４を係合解除方向に作動させるキー２６を抜き差し可能にするキー孔２５が凹所１９の内部と連通するよう設けられている。ラッチ１４の先端部１４ａと受け凹部１５との間には、内圧解放時のマンホール蓋４の浮上を許すための浮上隙間Ｅが設けられている。
【０００８】
ここでは、接合突起８がマンホール蓋４に設けられて接合凹部９が受枠２に設けられている場合と、接合突起８が受枠２に設けられて接合凹部９がマンホール蓋４に設けられている場合とが含まれる。また、ここでは、凹所１９がマンホール蓋４に設けられて受け凹部１５が受枠２に設けられている場合と、受け凹部１５がマンホール蓋４に設けられて凹所１９が受枠２に設けられている場合とが含まれる。
【０００９】
上記のラッチ１４は、その先端部１４ａの横幅方向の中心Ｃが、接合突起８の横幅方向の中心Ａとマンホール蓋４の中心Ｏとを結ぶ直線Ｂからずれた位置に配置されており、これに応じた位相位置に受け凹部１５と接合凹部９とが配置されているものとすることができる。
【００１０】
【発明の作用効果】
本発明によれば、マンホール蓋４を、凹凸係合構造１０と錠止構造１３とで閉蓋ロックできるようにし、従来不可欠であったヒンジ金具を省略するので、その分だけ閉蓋ロック機構を簡素化し、コストを削減できる。接合突起８と接合凹部９との間、およびラッチ１４の先端部１４ａと受け凹部１５との間にそれぞれに浮上隙間Ｅを設けるので、マンホール内に流水やガスが充満し内圧が高まると、マンホール蓋４が浮上して流水やガスを逃がし、マンホール蓋４の破壊や脱落に伴う二次災害の発生を防止できる。
【００１１】
マンホール蓋４は、錠止構造１３を解錠操作するだけで受枠２から取り外すことができるので、１人の作業者のみでマンホール蓋４を開閉できるうえ、接合突起８と接合凹部９との係合を解除してしまえば、マンホール蓋４を受枠２から完全に分離できるので、全解放時の蓋移動量を最小限化して、蓋開閉時の作業者の負担を軽減できる。しかも、接合突起８と接合凹部９とが横向きに凹凸係合するとともに、ラッチ１４と受け凹部１５とが横向きに係合するので、それらの厚さが小さくて済み、その分だけマンホール蓋４を開ける際にマンホール蓋４をあまり持ち上げなくても済んで、これによっても作業者の負担を軽減できる。
【００１２】
キー２６をキー孔２５に入れ、ラッチ１４を係合解除方向に作動させてラッチ１４の先端部１４ａを受け凹部１５から外さないと、マンホール蓋４を開放できないので、いたずらによる蓋開放をよく防止できる。
【００１３】
ラッチ１４の先端部１４ａの横幅方向の中心Ｃが、接合突起８の横幅方向の中心Ａとマンホール蓋４の中心Ｏとを結ぶ直線Ｂからずれた位置に配置されて、これに応じた位相位置に受け凹部１５と接合凹部９とが配置されていると、誤ってマンホール蓋４を水平方向へ１８０度反転した状態で受枠２に装着しようとしても、接合突起８が受け凹部１５に嵌合できないとともに、ラッチ１４の先端部１４ａが接合凹部９に嵌合できないことになり、誤装着を確実に防止できることになる。
【００１４】
【発明の実施の形態】
（第１実施例）図１ないし図６は、本発明に係るマンホール蓋構造の第１実施例を示す。図１において、１はマンホール口、２はマンホール口１にアンカーボルト３で据え付けられた状態で路面などに埋設される環状の受枠、４は受枠２内に嵌め込まれる円板形状のマンホール蓋であり、このマンホール蓋４は、下面が下凸状に湾曲する普通鋳鉄（ＦＣ）製の鋳造品からなる。そして、マンホール蓋４が、受枠２に対し着脱自在に嵌め込み装着されている。
【００１５】
受枠２は、環状の筒壁２ａの下端外周縁にフランジ状のベース２ｂを張り出した普通鋳鉄（ＦＣ）製の鋳造品からなる。筒壁２ａの内面には、マンホール蓋４が装着される装填部５が設けてある。装填部５は、下方に向かって漸次小径となる下すぼまりのテーパ面（内周面）５ａと、マンホール蓋４の下面周縁の接合座７を受け止める段壁５ｂとからなる。マンホール蓋４の外周面６は、下方に向かって漸次小径となる下すぼまりのテーパ状に形成されている。
【００１６】
そして、マンホール蓋４が装填部５に嵌め込まれて、マンホール蓋４の接合座７が段壁５ｂで受け止められた状態で（図１の状態）、マンホール蓋４の外周面６と受枠２のテーパ面５ａとが、例えば数mm程度の隙間を介した状態で対向している。この隙間によって、後述するマンホール蓋４の接合突起８を受枠２の接合凹部９へ嵌め込む際の操作が容易になる。
【００１７】
マンホール蓋４は、内圧解放機能を有する閉蓋ロック機構を介して受枠２に連結される。つまり、図１において閉蓋ロック機構は、マンホール蓋４の外周面６と受枠２のテーパ面５ａとの間に設けた凹凸係合構造１０と、この凹凸係合構造１０とマンホール蓋４の径方向にほぼ対向する位相位置においてマンホール蓋４の下面と受枠２との間に設けた錠止構造１３とで構成する。
【００１８】
凹凸係合構造１０は、マンホール蓋４の外周面６の下端寄りに横向きに突設した接合突起８と、受枠２のテーパ面５ａに凹み形成した接合凹部９とからなり、両者８・９の横向きの凹凸係合によって、マンホール蓋４を一定量上昇変位可能に、しかし分離は不能に接合している。
【００１９】
接合突起８と接合凹部９の内面上壁９ａとの間には、マンホール蓋４の上昇変位（浮上）を許すための浮上隙間Ｅを設けてあり、この浮上隙間Ｅの範囲内を接合突起８が上方変位できるようにしている。また、マンホール蓋４が周方向に若干ずれても接合突起８が接合凹部９に嵌合できるように、図２に示すごとく接合凹部９の横幅方向（図２では上下方向）の幅寸法Ｌ１は、接合突起８の横幅方向の幅寸法Ｌ２よりも、例えば５mm程度大きくしている。
【００２０】
錠止構造１３は、図１に示すごとくマンホール蓋４側に装着されたラッチ１４と、受枠２のテーパ面５ａに凹み形成した受け凹部１５とを備えており、ラッチ１４と受け凹部１５とが横向きに係合する。ラッチ１４は、図３に示すごとくほぼ四角形の平板状に形成されており、その先端面と下面の交わる角に円弧またはフラットな斜面１６（図１）を形成しており、一側面にキー受け凹部１７を形成している。キー受け凹部１７の後面１７ａは、後述するキー孔２５へ差し入れられたキー２６がラッチ１４の上面に干渉しないよう傾斜面に形成されている（図１参照）。
【００２１】
マンホール蓋４の外周面６の一部には、ラッチ１４を収容するための凹所１９が受枠２の受け凹部１５と向き合って開口するように設けられている。また、マンホール蓋４が周方向に若干ずれてもラッチ１４の先端部１４ａが受け凹部１５に嵌合できるように、受け凹部１５の横幅方向（図３では上下方向）の幅寸法Ｌ３は、ラッチ１４の先端部１４ａの幅寸法Ｌ４よりも、例えば５mm程度大きくしている。
【００２２】
凹所１９の底側は、図１に示すごとくマンホール蓋４の内面から下方へ膨出状に一体形成される底壁２０で塞がれており、凹所１９の内部とマンホール口１の内部とがその底壁２０で遮断される。底壁２０の外周面２１は、マンホール蓋４の外周面６と面一なテーパ状に形成されている。
【００２３】
ラッチ１４の下面には、図３に示すごとくマンホール蓋４の径方向（図３では左右方向）に細長い溝２２を設けてある。この溝２２に、底壁２０から突設したストッパーピン２３の先端を嵌合することで、ラッチ１４の先端部１４ａが凹所１９から突出して受枠２の受け凹部１５に嵌合する位置（図３の位置）と凹所１９内へ退入する位置（図４の位置）とにわたって直線往復移動自在になるように、ラッチ１４が凹所１９内に組み込まれる。そして、ラッチ１４の後端（図３では右端）と凹所１９の内奥壁との間にばね部材２４を介在させており、このばね作用でラッチ１４を常に突出方向に押圧付勢している。
【００２４】
マンホール蓋４の上昇変位（浮上）を許すために、図１に示すごとくラッチ１４の先端部１４ａの上方に、前記凹凸係合構造１０と同様に浮上隙間Ｅを確保しており、この浮上隙間Ｅの範囲内をラッチ１４の先端部１４ａが上方変位できるようにしている。
【００２５】
図５に示すごとく、錠止構造１３のラッチ１４の先端部１４ａの横幅方向（図５では上下方向）の中心Ｃが、凹凸係合構造１０の接合突起８の横幅方向の中心Ａとマンホール蓋４の中心Ｏとを結ぶ直線Ｂからずれた位置に配置されており、これに応じた位相位置に受け凹部１５と接合凹部９とが配置されている。さらに、接合突起８の横幅方向の幅寸法Ｌ２が受け凹部１５の横幅方向の幅寸法Ｌ３よりも大きくなっている。
【００２６】
これにより、誤ってマンホール蓋４を水平方向へ１８０度反転した状態で受枠２に装着しようとしても、接合突起８が受け凹部１５に嵌合できないとともに、ラッチ１４の先端部１４ａが接合凹部９に嵌合できないことになり、誤装着が確実に阻止される。
【００２７】
マンホール蓋４の上面の外周寄り部位には、図３に示すごとくほぼＩ字状に形成されたキー孔２５がラッチ１４のキー受け凹部１７の上方に対応するように開口されており、このキー孔２５の上側からキー２６を差し入れ可能になっている。つまり図６に示すごとく、キー２６の棒２７の下端には、その棒２７を挟んで直線状に配置された一対のキー片２８・２８が直角に備えられていて、キー片２８・２８を棒２７と共にキー孔２５に差し入れ可能になっている。
【００２８】
以上のように構成したマンホール蓋構造によれば、マンホール内に充満する流水の圧力などがマンホール蓋４に作用するとき、先の浮上隙間Ｅの分だけ接合突起８が上方移動して、受枠２の接合凹部９の内面上壁９ａ（図１）で受け止められる。また、ラッチ１４の先端が前記浮上隙間Ｅの分だけ上方移動して、受枠２の受け凹部１５の内面上壁１５ａ（図１）で受け止められる。
【００２９】
この浮上動作によってマンホール蓋４の外周面６と受枠２のテーパ面５ａとの間に大きな隙間が生じて、マンホール内の流水などが隙間を介して流出される。従って、マンホール内の圧力が異常に高くなってマンホール蓋４が吹き飛ばされたり、受枠２から脱落したりするのを阻止できる。なお、前記内圧が減じると、マンホール蓋４は自重で閉蓋位置へ復帰下降する。
【００３０】
マンホール蓋４を開放するときには、キー２６のキー片２８・２８をキー孔２５から凹所１９内に差し入れて、図４に示すごとく棒２７の軸心まわりに９０度回動させる。このキー２６の回動操作により、キー片２８・２８の一方が、ラッチ１４のキー受け凹部１７に係入された状態でラッチ１４をばね部材２４の力に抗して退入させることができ、この退入に伴いラッチ１４の先端部１４ａと受け凹部１５との係合が解除される（図４の状態）。
【００３１】
また、前記棒２７の軸心まわりに９０度回動させた状態では、キー片２８・２８が凹所１９の上面に突き当たることで上方へは抜け止め状になっており、このままキー２６を持ち上げることでマンホール蓋４が持ち上がる。そして、キー２６を引っ張るなどしてマンホール蓋４の裏側の縁を装填部４の開口周縁壁上に斜めに引きずり上げることで、接合突起８が接合凹部９から抜き出される。なお、この傾斜状態において接合突起８が接合凹部９の底壁に接当干渉するのを防ぐために、接合突起８の下面は僅かに傾斜している（図１参照）。
【００３２】
以後は、キー２６を引っ張るなどして、例えば、マンホール蓋４の全体を水平方向へ１８０度旋回させて、マンホール蓋４を受枠２の外へ移動させる。これによりマンホール口１が完全に開放される。
【００３３】
マンホール蓋４を受枠２内に嵌め込み装着するときには、マンホール蓋４の裏側の縁を装填部５の開口周縁壁上に載せてマンホール蓋４をずれ動かし、マンホール蓋４を傾斜させた姿勢で接合突起８を接合凹部９に嵌合させる。
【００３４】
この接合突起８と接合凹部９との嵌合に伴ってマンホール蓋４が受枠２内に入り込み、ラッチ１４の先端部１４ａの斜面１６が受枠２の内周上端に当たる。すると、嵌め込み力の分力でラッチ１４がばね部材２４の力に抗して凹所１９内に引っ込む。そして、マンホール蓋４の接合座７が受枠２の段壁５ｂで受け止められるよう完全に閉じると、受枠２の受け凹部１５と凹所１９とが合致し、ラッチ１４は、ばね部材２４の復元力で突出移動して受け凹部１５内に係合する施錠状態が得られる。
【００３５】
なお、キー孔２５は、常態時にはゴムなどの弾性を有するキャップを着脱自在に嵌合することで塞いで、キー孔２５から凹所１９内への雨水や砂などの侵入を防止するようにしてもよい。この場合、キャップは、キー２６を使用してマンホール蓋４を開けるときにのみキー孔２５から抜き出されることになる。
【００３６】
（第２実施例）図７は本発明の第２実施例を示す。この第２実施例では、錠止構造１３のラッチ１４は受枠２側に設けてあり、マンホール蓋４側に設けた凹所１９にラッチ１４を係合させるようにしている。つまり、マンホール蓋４の外周一部に、上記第１実施例の凹所１９と同様な底壁２０およびキー孔２５を有する凹所１９を凹み形成する。そして、受枠２のテーパ面５ａの一部にラッチ収容凹部３０を凹み形成し、このラッチ収容凹部３０にラッチ１４をこれの先端の斜面１６が上向きになるよう組み込む。
【００３７】
ラッチ１４の上面には、上記第１実施例と同様な受枠２の径方向に細長い溝２２を設けてあり、この溝２２に受枠２の上端から差し込まれたストッパーピン２３の下側先端を嵌合することで、ラッチ１４の先端部１４ａがラッチ収容凹部３０から突出して凹所１９に嵌合する位置（図７の位置）とラッチ収容凹部３０内へ退入する位置とにわたって、ラッチ１４がラッチ収容凹部３０内に直線往復移動するようにしてある。
【００３８】
そして、ラッチ１４の後端（図７では左端）とラッチ収容凹部３０の内奥壁との間に、ばね部材２４を介在させて、このばね作用でラッチ１４を常に突出方向に押圧付勢している。ラッチ１４の先端部１４ａと凹所１９の内面下壁との間には、マンホール蓋４の上昇変位（浮上）を許すために、上記第１実施例と同様に浮上隙間Ｅが設けられている。他は第１実施例と実質的に同様である。
【００３９】
マンホール蓋４を受枠２内に装着するときには、ラッチ１４の先端の斜面１６にマンホール蓋４の底壁２０の外周面２１が当たって、嵌め込み力の分力でラッチ１４がばね部材２４の力に抗してラッチ収容凹部３０内に引っ込む。更にマンホール蓋４の接合座７が受枠２の段壁５ｂで受け止められるよう完全に閉じると、ラッチ１４が、ばね部材２４の復元力で突出移動してマンホール蓋４の凹所１９内に係合する施錠状態が得られる。解錠に際しては、キー２６をキー孔２５から凹所１９内に入れてラッチ１４をラッチ収容凹部３０内に押し込めばよい。
【００４０】
前記各実施例において、受枠２のテーパ面５ａの上端寄りに接合突起８を配置するとともに、マンホール蓋４の外周面６に接合凹部９を凹み形成して、接合突起８と接合凹部９の内面下壁との間に浮上隙間Ｅを設けるようにしてもよい。この場合、接合凹部９は蓋上面において開口してもよい。
【図面の簡単な説明】
【図１】本発明に係るマンホール蓋構造の第１実施例を示す全体の縦断面図である。
【図２】凹凸係合構造の要部を示す平面図である。
【図３】錠止構造の要部を示す平面図である。
【図４】錠止構造の横断面図である。
【図５】マンホール蓋と受枠との平面図である。
【図６】キーの斜視図である。
【図７】第２実施例の錠止構造の要部を示す縦断面図である。
【符号の説明】
２受枠
４マンホール蓋
８接合突起
９接合凹部
１０凹凸係合構造
１３錠止構造
１４ラッチ
１４ａラッチの先端部
１５受け凹部
１９凹所
２４ばね部材
２５キー孔
２６キー
Ａ接合突起の横幅方向の中心
Ｂ接合突起の横幅方向の中心とマンホール蓋の中心とを結ぶ直線
Ｃラッチの先端部の横幅方向の中心
Ｅ浮上隙間
Ｏマンホール蓋の中心[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manhole cover structure provided with a cover lock mechanism.
[0002]
[Prior art]
An example of this type of manhole cover structure can be found in Japanese Patent Application Laid-Open No. 9-296470. There, a triangular locking metal fitting is suspended from the lower surface side of the manhole cover so as to be swingable around the axis, and a hinge metal fitting is disposed at a position facing the lower surface of the manhole cover.
[0003]
And, by engaging the locking metal fitting with the engaging portion provided in the receiving frame into which the manhole cover is fitted by its own weight, the manhole cover can be moved upward, but the disengagement is impossible to guide, Even if abnormal pumping pressure in the case of torrential rain or gas pressure generated in the manhole is applied to the manhole cover, the manhole cover is lifted and displaced to discharge the flowing water or gas that fills the manhole, thereby reducing the manhole internal pressure. I try to release.
[0004]
When opening the manhole cover, insert a bell crank key into the keyhole of the manhole cover, press the head of the lock fitting, and swing the lock fitting in the release direction against its own weight. The engagement state of the receiving frame with the engaging portion is released. In this state, the key is rotated 90 degrees around the axis, and the tip of the key is engaged with the key hole upward to prevent it from coming off, and the key is lifted as it is and the entire lid is turned upside down. The manhole cover is fully opened by pivoting the entire cover 180 degrees horizontally around the hinge fitting while the manhole cover is lifted up with a key or in a posture in which the manhole cover is lifted with a key.
[0005]
[Problems to be solved by the invention]
Since the manhole cover is made of spheroidal graphite cast iron (FCD) or the like and has a large weight, it is not easy to swing the manhole cover upside down as described above. Even when the manhole cover is swung in the horizontal direction, the lock metal fitting is suspended on the lower surface side of the manhole cover, so it is necessary to lift the manhole cover until the lock metal fitting is higher than the receiving frame. Only the operator is burdened.
[0006]
Accordingly, an object of the present invention has been made by paying attention to such a situation, and it is possible to fully open the manhole cover even if the lift amount of the manhole cover is small while releasing the internal pressure of the manhole. The object is to provide a manhole cover structure that can reduce the burden.
[0007]
[Means for Solving the Problems]
As shown in FIG. 1, the manhole cover structure of the present invention includes an annular receiving frame 2 and a manhole cover 4 that is detachably fitted to the receiving frame 2. In the meantime, a lid lock mechanism having an internal pressure releasing function is provided. The lid-locking mechanism is composed of an uneven engagement structure 10 and a locking structure 13 provided between the manhole cover 4 and the receiving frame 2, and the uneven engagement structure 10 and the locking structure 13 are arranged in the manhole. The lid 4 is disposed at a phase position facing the radial direction of the lid 4. The concavo-convex engagement structure 10 includes a joint protrusion 8 and a joint recess 9 that engage with each other in the lateral direction between the manhole cover 4 and the receiving frame 2, and an internal pressure is provided between the joint protrusion 8 and the joint recess 9. A floating gap E for allowing the manhole cover 4 to float when released is provided. The locking structure 13 includes a latch 14 and a receiving recess 15 that are laterally engaged between the manhole cover 4 and the receiving frame 2. The latch 14 is accommodated in a recess 19 that opens toward the receiving recess 15, and the distal end portion 14 a of the latch 14 can be freely engaged and disengaged with respect to the receiving recess 15. Is biased toward the receiving recess 15 by a spring member 24 accommodated in the housing. A key hole 25 that allows the key 26 that operates the latch 14 in the disengagement direction to be inserted and removed is provided in the vicinity of the outer periphery of the upper surface of the manhole cover 4 so as to communicate with the inside of the recess 19. A floating gap E is provided between the tip 14a of the latch 14 and the receiving recess 15 to allow the manhole cover 4 to float when the internal pressure is released.
[0008]
Here, the joint protrusion 8 is provided on the manhole cover 4 and the joint recess 9 is provided on the receiving frame 2, and the joint protrusion 8 is provided on the receiver frame 2 and the joint recess 9 is provided on the manhole cover 4. Includes cases. Further, here, the recess 19 is provided in the manhole cover 4 and the receiving recess 15 is provided in the receiving frame 2, and the receiving recess 15 is provided in the manhole cover 4 and the recess 19 is provided in the receiving frame 2. Is included.
[0009]
The latch 14 is disposed at a position where the center C in the width direction of the tip end portion 14a is shifted from the straight line B connecting the center A in the width direction of the joint protrusion 8 and the center O of the manhole cover 4, The receiving concave portion 15 and the joint concave portion 9 can be arranged at a phase position corresponding to the above.
[0010]
[Effects of the invention]
According to the present invention, the manhole cover 4 can be closed and locked by the concave-convex engagement structure 10 and the locking structure 13, and the hinge fitting which has been indispensable in the past is omitted. Simplify and reduce costs. Since the floating gap E is provided between the joint projection 8 and the joint recess 9 and between the tip 14a of the latch 14 and the receiving recess 15, the manhole is filled with running water or gas and the internal pressure increases. The lid 4 rises and the running water and gas escape, and the occurrence of a secondary disaster due to the destruction or dropping off of the manhole cover 4 can be prevented.
[0011]
Since the manhole cover 4 can be removed from the receiving frame 2 simply by unlocking the locking structure 13, the manhole cover 4 can be opened and closed by only one operator, and the connection between the joint protrusion 8 and the joint recess 9 can be performed. If the joint is released, the manhole cover 4 can be completely separated from the receiving frame 2, so that the amount of movement of the cover when fully released can be minimized, and the burden on the operator when opening and closing the cover can be reduced. In addition, since the joint protrusion 8 and the joint recess 9 engage with the concave and convex portions in the horizontal direction, and the latch 14 and the receiving concave portion 15 engage with each other in the lateral direction, their thicknesses can be reduced, and the manhole cover 4 can be reduced accordingly. When opening, it is not necessary to lift the manhole cover 4 so much, thereby reducing the burden on the operator.
[0012]
Since the manhole cover 4 cannot be opened unless the key 26 is inserted into the key hole 25 and the latch 14 is operated in the disengagement direction to remove the leading end 14a of the latch 14 from the recess 15, the cover opening due to mischief is well prevented. it can.
[0013]
The center C in the width direction of the front end portion 14a of the latch 14 is disposed at a position shifted from the straight line B connecting the center A in the width direction of the joint protrusion 8 and the center O of the manhole cover 4, and a phase position corresponding to this. If the receiving recessed portion 15 and the joining recessed portion 9 are arranged, the joining projection 8 cannot be fitted into the receiving recessed portion 15 even if the manhole cover 4 is mistakenly attached to the receiving frame 2 while being inverted 180 degrees in the horizontal direction. At the same time, the distal end portion 14a of the latch 14 cannot be fitted into the joint recess 9, and erroneous mounting can be reliably prevented.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment FIGS. 1 to 6 show a first embodiment of a manhole cover structure according to the present invention. In FIG. 1, 1 is a manhole port, 2 is an annular receiving frame embedded in a road surface or the like while being installed in the manhole port 1 with an anchor bolt 3, and 4 is a disk-shaped manhole cover fitted in the receiving frame 2. The manhole cover 4 is made of a cast product made of ordinary cast iron (FC) whose bottom surface is curved downwardly. A manhole cover 4 is detachably fitted to the receiving frame 2.
[0015]
The receiving frame 2 is made of a cast product made of ordinary cast iron (FC) in which a flange-like base 2b projects from the outer peripheral edge of the lower end of the annular cylindrical wall 2a. On the inner surface of the cylindrical wall 2a, a loading portion 5 to which the manhole cover 4 is attached is provided. The loading portion 5 includes a tapered surface (inner peripheral surface) 5a having a gradually narrowing diameter toward the lower side and a step wall 5b for receiving the joint seat 7 on the lower peripheral edge of the manhole cover 4. The outer peripheral surface 6 of the manhole cover 4 is formed in a tapered shape having a downward concavity that gradually becomes smaller in diameter downward.
[0016]
Then, with the manhole cover 4 fitted into the loading portion 5 and the joint seat 7 of the manhole cover 4 being received by the step wall 5b (the state of FIG. 1), the outer peripheral surface 6 of the manhole cover 4 and the taper of the receiving frame 2 The surface 5a is opposed to the surface 5a with a gap of about several mm, for example. This gap facilitates an operation when fitting a joint projection 8 of the manhole cover 4 to be described later into the joint recess 9 of the receiving frame 2.
[0017]
The manhole cover 4 is connected to the receiving frame 2 through a closing lock mechanism having an internal pressure releasing function. In other words, in FIG. 1, the lid lock mechanism includes an uneven engagement structure 10 provided between the outer peripheral surface 6 of the manhole cover 4 and the tapered surface 5 a of the receiving frame 2, and the diameters of the uneven engagement structure 10 and the manhole cover 4. The locking structure 13 is provided between the lower surface of the manhole cover 4 and the receiving frame 2 at a phase position substantially opposite to the direction.
[0018]
The concavo-convex engagement structure 10 includes a joint protrusion 8 projecting laterally toward the lower end of the outer peripheral surface 6 of the manhole cover 4 and a joint recess 9 formed in a recess on the tapered surface 5a of the receiving frame 2. The manhole cover 4 is joined so that the manhole cover 4 can be displaced up by a certain amount, but cannot be separated, by the lateral concave and convex engagement.
[0019]
A floating gap E is provided between the joint protrusion 8 and the inner surface upper wall 9a of the joint recess 9 to allow the manhole cover 4 to be displaced upward (floating). Can be displaced upward. Further, as shown in FIG. 2, the width dimension L1 in the lateral width direction (vertical direction in FIG. 2) of the joint recess 9 is such that the joint projection 8 can be fitted into the joint recess 9 even if the manhole cover 4 is slightly displaced in the circumferential direction. The width dimension L2 of the joining protrusion 8 in the lateral width direction is, for example, about 5 mm larger.
[0020]
As shown in FIG. 1, the locking structure 13 includes a latch 14 mounted on the manhole cover 4 side, and a receiving recess 15 that is recessed in the tapered surface 5 a of the receiving frame 2. Engage sideways. As shown in FIG. 3, the latch 14 is formed in a substantially rectangular flat plate shape, and an arc or a flat slope 16 (FIG. 1) is formed at a corner where the front end surface and the lower surface intersect, and a key receiver is formed on one side surface. A recess 17 is formed. The rear surface 17a of the key receiving recess 17 is formed as an inclined surface so that the key 26 inserted into the key hole 25 described later does not interfere with the upper surface of the latch 14 (see FIG. 1).
[0021]
A recess 19 for receiving the latch 14 is provided in a part of the outer peripheral surface 6 of the manhole cover 4 so as to face the receiving recess 15 of the receiving frame 2 and open. Further, the width dimension L3 in the horizontal width direction (vertical direction in FIG. 3) of the receiving recess 15 is set so that the leading end 14a of the latch 14 can be fitted into the receiving recess 15 even if the manhole cover 4 is slightly displaced in the circumferential direction. For example, it is made larger by about 5 mm than the width dimension L4 of the tip portion 14a.
[0022]
As shown in FIG. 1, the bottom side of the recess 19 is closed by a bottom wall 20 integrally formed so as to bulge downward from the inner surface of the manhole cover 4, and the inside of the recess 19 and the inside of the manhole port 1 are covered. Are blocked by the bottom wall 20. The outer peripheral surface 21 of the bottom wall 20 is formed in a tapered shape that is flush with the outer peripheral surface 6 of the manhole cover 4.
[0023]
On the lower surface of the latch 14, as shown in FIG. 3, an elongated groove 22 is provided in the radial direction of the manhole cover 4 (left and right direction in FIG. 3). By fitting the tip of a stopper pin 23 projecting from the bottom wall 20 into this groove 22, the tip 14 a of the latch 14 protrudes from the recess 19 and fits into the receiving recess 15 of the receiving frame 2 (see FIG. The latch 14 is incorporated in the recess 19 so as to be freely reciprocated linearly between the position 3 and the position retracting into the recess 19 (position in FIG. 4). A spring member 24 is interposed between the rear end of the latch 14 (the right end in FIG. 3) and the inner wall of the recess 19, and this spring action always presses and urges the latch 14 in the protruding direction. Yes.
[0024]
In order to allow the manhole cover 4 to move upward (floating), a floating gap E is secured above the tip 14a of the latch 14 as shown in FIG. Within the range of E, the front end portion 14a of the latch 14 can be displaced upward.
[0025]
As shown in FIG. 5, the center C in the lateral width direction (vertical direction in FIG. 5) of the distal end portion 14 a of the latch 14 of the locking structure 13 is the center A in the lateral direction of the joint protrusion 8 of the concave-convex engagement structure 10 and the manhole cover. The receiving recess 15 and the joining recess 9 are arranged at a phase position corresponding to the position B. Further, the width dimension L2 of the bonding protrusion 8 in the lateral width direction is larger than the width dimension L3 of the receiving recess 15 in the lateral width direction.
[0026]
Accordingly, even if the manhole cover 4 is mistakenly attached to the receiving frame 2 in a state where the manhole cover 4 is inverted 180 degrees in the horizontal direction, the joining projection 8 cannot be fitted into the receiving recess 15, and the leading end 14 a of the latch 14 is brought into the joining recess 9. It will be impossible to fit, and erroneous mounting will be reliably prevented.
[0027]
A key hole 25 formed in an approximately I shape as shown in FIG. 3 is opened at a position near the outer periphery of the upper surface of the manhole cover 4 so as to correspond to the upper side of the key receiving recess 17 of the latch 14. A key 26 can be inserted from above the hole 25. That is, as shown in FIG. 6, a pair of key pieces 28, 28 arranged in a straight line across the rod 27 are provided at the lower end of the rod 27 of the key 26. It can be inserted into the key hole 25 together with the rod 27.
[0028]
According to the manhole cover structure configured as described above, when the pressure of the flowing water filling the manhole acts on the manhole cover 4, the joint protrusion 8 moves upward by the amount of the previous floating gap E, and the receiving frame 2 Are received by the inner surface upper wall 9a (FIG. 1). Further, the tip of the latch 14 moves upward by the amount of the floating gap E and is received by the inner surface upper wall 15 a (FIG. 1) of the receiving recess 15 of the receiving frame 2.
[0029]
This floating operation creates a large gap between the outer peripheral surface 6 of the manhole cover 4 and the tapered surface 5a of the receiving frame 2, and the running water in the manhole flows out through the gap. Accordingly, it is possible to prevent the pressure in the manhole from becoming abnormally high and the manhole cover 4 from being blown off or dropped from the receiving frame 2. When the internal pressure decreases, the manhole cover 4 returns to the closed position by its own weight.
[0030]
When the manhole cover 4 is opened, the key pieces 28 and 28 of the key 26 are inserted into the recess 19 from the key hole 25 and rotated 90 degrees around the axis of the rod 27 as shown in FIG. By rotating the key 26, the latch 14 can be retracted against the force of the spring member 24 in a state where one of the key pieces 28 and 28 is engaged in the key receiving recess 17 of the latch 14. With this retraction, the engagement between the tip 14a of the latch 14 and the receiving recess 15 is released (state shown in FIG. 4).
[0031]
When the key 27 is rotated 90 degrees around the axis of the rod 27, the key pieces 28 and 28 come into contact with the upper surface of the recess 19 so that the key 26 is lifted as it is. As a result, the manhole cover 4 is lifted. Then, the joining projection 8 is extracted from the joining recess 9 by pulling the key 26 obliquely and pulling the edge of the back side of the manhole cover 4 obliquely onto the opening peripheral wall of the loading portion 4. In this inclined state, the lower surface of the bonding protrusion 8 is slightly inclined to prevent the bonding protrusion 8 from coming into contact with the bottom wall of the bonding recess 9 (see FIG. 1).
[0032]
Thereafter, by pulling the key 26, for example, the entire manhole cover 4 is turned 180 degrees horizontally to move the manhole cover 4 out of the receiving frame 2. Thereby, the manhole port 1 is completely opened.
[0033]
When the manhole cover 4 is fitted into the receiving frame 2 and mounted, the edge of the back side of the manhole cover 4 is placed on the peripheral wall of the opening of the loading portion 5 so that the manhole cover 4 is displaced and the manhole cover 4 is tilted so as to be inclined. 8 is fitted into the joint recess 9.
[0034]
As the joint protrusion 8 and the joint recess 9 are fitted, the manhole cover 4 enters the receiving frame 2, and the inclined surface 16 of the tip 14 a of the latch 14 hits the inner peripheral upper end of the receiving frame 2. Then, the latch 14 is retracted into the recess 19 against the force of the spring member 24 by the component force of the fitting force. When the joint seat 7 of the manhole cover 4 is completely closed so as to be received by the step wall 5 b of the receiving frame 2, the receiving recess 15 and the recess 19 of the receiving frame 2 are matched, and the latch 14 has a restoring force of the spring member 24. Thus, a locked state is obtained in which the protrusion moves and engages in the receiving recess 15.
[0035]
In addition, the key hole 25 is closed by detachably fitting a cap having elasticity such as rubber in a normal state so as to prevent intrusion of rainwater or sand from the key hole 25 into the recess 19. Also good. In this case, the cap is extracted from the key hole 25 only when the manhole cover 4 is opened using the key 26.
[0036]
Second Embodiment FIG. 7 shows a second embodiment of the present invention. In the second embodiment, the latch 14 of the locking structure 13 is provided on the receiving frame 2 side, and the latch 14 is engaged with a recess 19 provided on the manhole cover 4 side. That is, a recess 19 having a bottom wall 20 and a key hole 25 similar to the recess 19 of the first embodiment is formed in a part of the outer periphery of the manhole cover 4. Then, a latch receiving recess 30 is formed in a part of the tapered surface 5a of the receiving frame 2, and the latch 14 is assembled in the latch receiving recess 30 so that the inclined surface 16 of the tip thereof faces upward.
[0037]
The upper surface of the latch 14 is provided with a groove 22 elongated in the radial direction of the receiving frame 2 similar to the first embodiment, and the lower end of the stopper pin 23 inserted from the upper end of the receiving frame 2 is fitted into the groove 22. As a result, the latch 14 extends over the position where the tip 14a of the latch 14 protrudes from the latch receiving recess 30 and fits into the recess 19 (the position shown in FIG. 7) and the position where the latch 14 retracts into the latch receiving recess 30. A linear reciprocating movement is made in the latch receiving recess 30.
[0038]
A spring member 24 is interposed between the rear end of the latch 14 (the left end in FIG. 7) and the inner back wall of the latch receiving recess 30, and this spring action always presses and urges the latch 14 in the protruding direction. ing. A floating gap E is provided between the front end portion 14a of the latch 14 and the lower inner wall of the recess 19 in order to allow the manhole cover 4 to be displaced upward (floating) as in the first embodiment. . Others are substantially the same as the first embodiment.
[0039]
When the manhole cover 4 is mounted in the receiving frame 2, the outer peripheral surface 21 of the bottom wall 20 of the manhole cover 4 hits the inclined surface 16 of the tip of the latch 14, and the latch 14 is applied to the force of the spring member 24 by the component force of the fitting force. The latch is retracted into the latch receiving recess 30. Further, when the joint seat 7 of the manhole cover 4 is completely closed so as to be received by the step wall 5b of the receiving frame 2, the latch 14 protrudes by the restoring force of the spring member 24 and engages in the recess 19 of the manhole cover 4. A locked state is obtained. When unlocking, the key 26 may be inserted into the recess 19 through the key hole 25 and the latch 14 may be pushed into the latch receiving recess 30.
[0040]
In each of the above embodiments, the joint protrusion 8 is disposed near the upper end of the tapered surface 5 a of the receiving frame 2, and the joint recess 9 is formed in the outer peripheral surface 6 of the manhole cover 4. A floating gap E may be provided between the lower wall and the lower wall. In this case, the joint recess 9 may be opened on the upper surface of the lid.
[Brief description of the drawings]
FIG. 1 is an overall longitudinal sectional view showing a first embodiment of a manhole cover structure according to the present invention.
FIG. 2 is a plan view showing a main part of the uneven engagement structure.
FIG. 3 is a plan view showing a main part of the locking structure.
FIG. 4 is a cross-sectional view of the locking structure.
FIG. 5 is a plan view of a manhole cover and a receiving frame.
FIG. 6 is a perspective view of a key.
FIG. 7 is a longitudinal sectional view showing the main part of the locking structure of the second embodiment.
[Explanation of symbols]
2 Receiving frame 4 Manhole cover 8 Joining protrusion 9 Joining recess 10 Uneven engagement structure 13 Locking structure 14 Latch 14a Latch tip 15 Receiving recess 19 Recess 24 Spring member 25 Key hole 26 Key A Center width B of joining protrusion A straight line C connecting the center of the joint protrusion in the width direction and the center of the manhole cover The center in the width direction of the leading end of the latch E Floating gap O Center of the manhole cover

Claims

An annular receiving frame (2), and a manhole cover (4) that is detachably fitted to the receiving frame (2).
A manhole cover structure in which a closing lock mechanism having an internal pressure releasing function is provided between the manhole cover (4) and the receiving frame (2),
The closing lock mechanism is composed of a concave and convex engagement structure (10) and a locking structure (13) provided between the manhole cover (4) and the receiving frame (2).
The concavo-convex engagement structure (10) and the locking structure (13) are respectively arranged at phase positions facing the radial direction of the manhole cover (4),
The concavo-convex engagement structure (10) includes a joint protrusion (8) and a joint recess (9) that are concavo-convexly engaged between the manhole cover (4) and the receiving frame (2).
Between the joint protrusion (8) and the joint recess (9), a floating gap (E) for allowing the manhole cover (4) to float when the internal pressure is released is provided,
The locking structure (13) includes a latch (14) and a receiving recess (15) that are laterally engaged between the manhole cover (4) and the receiving frame (2).
The latch (14) has a key receiving recess (17) formed on one side thereof, and a rear surface (17a) of the key receiving recess (17) formed on an inclined surface,
The latch (14) is housed in a recess (19) that opens toward the receiving recess (15), and the distal end (14a) of the latch (14) is freely disengageable with respect to the receiving recess (15). And is biased toward the receiving recess (15) by the spring member (24) housed in the recess (19),
A key (26) for operating the latch (14) in the disengagement direction at a position near the outer periphery of the upper surface of the manhole cover (4) and above the key receiving recess (17) of the latch (14). A substantially I-shaped key hole (25) that allows insertion / removal of the latch (14) is formed at right angles to the engaging / disengaging direction of the latch (14), and is provided to communicate with the interior of the recess (19). And
A floating gap (E) for allowing the manhole cover (4) to float when the internal pressure is released is provided between the tip (14a) of the latch (14) and the receiving recess (15). Manhole cover structure.

The center (C) in the lateral direction of the tip (14a) of the latch (14) is a straight line (B 2. The manhole cover structure according to claim 1, wherein the receiving concave portion (15) and the joint concave portion (9) are arranged at a phase position corresponding to this position.