초록 ▼

The present invention provides a fuel cap having a high operability while maintaining the air-tightness thereof at a necessary and sufficient level. The closure includes a closure body having a head portion, a trunk portion and an annular trunk surface having stopper projections; a seal ring; a slee

The present invention provides a fuel cap having a high operability while maintaining the air-tightness thereof at a necessary and sufficient level. The closure includes a closure body having a head portion, a trunk portion and an annular trunk surface having stopper projections; a seal ring; a sleeve; a coiled spring; and an engagement member having engagement projections. The fuel cap is formed by assembling the seal ring around the annular surface of the trunk portion of the closure body and the sleeve with the trunk portion in the mentioned order, interposing the coiled spring between the sleeve and engagement member, and connecting the engagement member to the trunk portion of the closure body.

대표청구항 ▼

What is claimed is: 1. A fuel cap comprising a closure to be secured in an oil filler port attached to an inlet of a feed oil pipe, and a handle for turning the closure, the oil filler port being provided on an inner side surface thereof with a plurality of circumferentially extending ribs intermit

What is claimed is: 1. A fuel cap comprising a closure to be secured in an oil filler port attached to an inlet of a feed oil pipe, and a handle for turning the closure, the oil filler port being provided on an inner side surface thereof with a plurality of circumferentially extending ribs intermittently, the closure including: a closure body having a head portion to be turned, a trunk portion extending downward from the head portion, and an annular trunk surface with downwardly extending stopper projections formed on a side surface of the trunk portion, a seal ring which is fitted around the trunk portion so that the seal ring is fitted between a lower surface of the head portion and an upper portion of the annular trunk surface, and which pressure-contacts with an inner side surface of the oil filler port in radius direction from an inner side thereof, a sleeve with annular shape having on an inner side surface thereof an annular sleeve surface provided with stopper recesses into which the stopper projections are fitted, and on an outer side surface thereof downwardly extending anti-rotation projections which are fitted in clearances between the ribs, and adapted to lift up the seal ring, a coiled spring urging the sleeve upward, and an engagement member having engagement projections adapted to be turned through the clearances between the ribs of the oil filler port and thereby engaged with the ribs from a lower side thereof, and formed by integrally assembling these parts in the mentioned order; the holding of the seal ring by the lower surface of the head portion of the closure body and an upper surface of the sleeve becoming: tight when the stopper projections of the closure body are fitted in the stopper recesses to cause the sleeve to be lifted by a force of the coiled spring, and loose when the stopper projections are disengaged from the stopper recesses and run on the annular sleeve surface to cause the sleeve to be pressed down against the force of the coiled spring. 2. The fuel cap according to claim 1, wherein the stopper recesses of the sleeve are provided on the annular sleeve surface in the circumferential positions corresponding to a securing-started stage and a securing-finished stage respectively, and the engagement projections of the engagement member are provided on an outer side surface of the engagement member in the circumferential positions corresponding to the securing-started stage. 3. The fuel cap according to claim 2, wherein the sleeve has the annular sleeve surface inclining downward from the stopper recesses provided thereon in the circumferential positions corresponding to the securing-started stage toward the stopper recesses provided thereon in the circumferential positions corresponding to the securing-finished stage, and thereby carrying out the reliable turning operation of the fuel cap in closing direction by utilizing smooth movement of the stopper projections of the closure body on the annular sleeve surface. 4. The fuel cap according to claim 2, wherein the sleeve has the annular sleeve surface inclining downward from the stopper recesses provided thereon in the circumferential positions corresponding to the securing-finished stage toward the stopper recesses provided thereon in the circumferential positions corresponding to the securing-started stage, and thereby carrying out the reliable turning operation of the fuel cap in opening direction by utilizing smooth movement of the stopper projections of the closure body on the annular sleeve surface. 5. The fuel cap according to claim 2, wherein: the depth of the stopper recesses of the sleeve provided in the circumferential positions corresponding to the securing-started stage is set relatively small, the depth of the stopper recesses of the sleeve provided in the circumferential positions corresponding to the securing-finished stage is set relatively large, and thereby carrying out the easiness of the disengaging of the stopper projections from the stopper recesses in the securing-started stage while maintaining the tight holding force of the seal ring obtained at the securing-finished stage. 6. The fuel cap according to claim 1, wherein the seal ring includes an upper annular edge to be fitted firmly around the trunk portion of the closure body, a lower annular edge diverging from the upper annular edge, and a frustum seal surface connecting the upper annular edge and the lower annular edge together and inclined downward in the outward radius direction, the upper surface of the sleeve and the lower surface of the head portion of the closure body holding therebetween the upper annular edge of the seal ring in the vertical direction. 7. The fuel cap according to claim 6, wherein the sleeve has a frustum surface inclined downward from the upper surface thereof at an angle smaller than the angle of inclination of the frustum seal surface of the seal ring and extending in the outer circumferential direction thereof, and the upper surface of the sleeve and the lower surface of the head portion of the closure body holding therebetween the upper annular edge of the seal ring in the vertical direction. 8. The fuel cap according to claim 6, wherein the upper annular edge of the seal ring is substantially horseshoe-shaped in the cross section thereof, and the upper surface of the sleeve and the lower surface of the head portion of the closure body holding therebetween the upper annular edge of the seal ring in the vertical direction. 9. The fuel cap according to claim 1, wherein the sleeve includes a lower sleeve and an upper sleeve, the lower sleeve having connecting recesses opening upwardly arranged to the inner side surface thereof, anti-rotation projections extending downwardly arranged to the outer side surface thereof so as to fit into clearances between the ribs, and engagement flanges extending radially outward engaged with the ribs, the upper sleeve having the annular sleeve surface arranged to the inner side surface thereof with the stopper recesses opening upwardly to receive the stopper projections, and connecting projections extending toward the lower sleeve arranged to the outer side surface thereof so as to fit into the connecting recesses, the closure is assembled integrally by the closure body, the seal ring, the upper sleeve, the coiled spring, the lower sleeve and the engagement member in the mentioned order; the holding of the seal ring by the lower surface of the head portion of the closure body and the upper surface of the upper sleeve becoming: tight when the stopper projections of the closure body are fitted in the stopper recesses of the upper sleeve to cause the upper sleeve to be lifted by a force of the coiled spring, and loose when the stopper projections are disengaged from the stopper recesses and run on the annular sleeve surface to cause the upper sleeve to be pressed down against the force of the coiled spring. 10. The fuel cap according to claim 1, wherein: the head portion of the closure body has a multi-step structure, the seal ring fitted around the trunk portion so that the seal ring is fitted between a lower surface of a lower step of the head portion and the annular trunk surface, and a retainer ring interposed between the frustum seal surface of the seal ring and the lower surface of the upper step of the head portion. 11. The fuel cap according to claim 10, wherein the stopper recesses of the sleeve are provided on the annular sleeve surface in the circumferential positions corresponding to the securing-started stage and the securing-finished stage respectively, and the engagement projections of the engagement member are provided on the outer side surface of the engagement member in the circumferential positions corresponding to the securing-started stage. 12. The fuel cap according to claim 11, wherein the sleeve has the annular sleeve surface inclining downward from the stopper recesses provided thereon in the circumferential positions corresponding to the securing-started stage toward the stopper recesses provided thereon in the circumferential positions corresponding to the securing-finished stage, and thereby carrying out the reliable turning operation of the fuel cap in closing direction by utilizing smooth movement of the stopper projections of the closure body on the annular sleeve surface. 13. The fuel cap according to claim 11, wherein the sleeve has the annular sleeve surface inclining downward from the stopper recesses provided thereon in the circumferential positions corresponding to the securing-finished stage toward the stopper recesses provided thereon in the circumferential positions corresponding to the securing-started stage, and thereby carrying out the reliable turning operation of the fuel cap in opening direction by utilizing smooth movement of the stopper projections of the closure body on the annular sleeve surface. 14. The fuel cap according to claim 11, wherein: the depth of the stopper recesses of the sleeve provided in the circumferential positions corresponding to the securing-started stage is set relatively small, the depth of the stopper recesses of the sleeve provided in the circumferential positions corresponding to the securing-finished stage is set relatively large, and thereby carrying out the easiness of the disengaging of the stopper projections from the stopper recesses in the securing-started stage while maintaining the tight holding force of the seal ring obtained at the securing-finished stage. 15. The fuel cap according to claim 10, wherein the seal ring includes the upper annular edge to be fitted firmly around the trunk portion of the closure body, the lower annular edge diverging from the upper annular edge, and the frustum seal surface connecting the upper annular edge and the lower annular edge together and inclined downward in the outward radius direction, the upper annular edge being held by the upper surface of the sleeve and the lower surface of the lower step of the head portion of the closure body, the lower annular edge pressure-contacting the outer circumferential surface thereof with the inner side surface of the oil filler port in radius direction from the center thereof, and the retainer ring including: an inner circumferential retainer portion fitted firmly around the side surface of the lower step of the head portion, an outer circumferential retainer portion contacted to the lower surface of the upper step of the head portion with an upper edge thereof and to the frustum seal surface with a lower edge thereof respectively, and thereby pressing the frustum seal surface of the seal ring from the upper side thereof by the outer circumferential retainer portion. 16. The fuel cap according to claim 15, wherein the sleeve has a frustum surface inclined downward from the upper surface thereof at an angle smaller than the angle of inclination of the frustum seal surface of the seal ring and extending in the outer circumferential direction thereof, and the upper surface of the sleeve and the lower surface of the lower step of the head portion of the closure body holding therebetween the upper annular edge of the seal ring in the vertical direction. 17. The fuel cap according to claim 15, wherein: the upper annular edge of the seal ring is substantially horseshoe-shaped in the cross section thereof, and the upper surface of the sleeve and the lower surface of the lower step of the head portion of the closure body holding therebetween the upper annular edge of the seal ring in the vertical direction. 18. The fuel cap according to claim 10, wherein the sleeve includes the lower sleeve and the upper sleeve, the lower sleeve having connecting recesses opening upwardly arranged to the inner side surface thereof, anti-rotation projections extending downwardly arranged to the outer side surface thereof so as to fit into clearances between the ribs, and engagement flanges extending radially outward engaged with the ribs, the upper sleeve having the annular sleeve surface arranged to the inner side surface thereof with the stopper recesses opening upwardly to receive the stopper projections, and connecting projections extending toward the lower sleeve arranged to the outer side surface thereof so as to be fit into the connecting recesses, the closure is assembled integrally by the closure body, the retainer ring, the seal ring, the upper sleeve, the coiled spring, the lower sleeve and the engagement member in the mentioned order; the holding of the seal ring by the lower surface of the lower step of the head portion of the closure body and the upper surface of the upper sleeve becoming: tight when the stopper projections of the closure body are fitted in the stopper recesses of the upper sleeve to cause the upper sleeve to be lifted by a force of the coiled spring, and loose when the stopper projections are disengaged from the stopper recesses and run on the annular sleeve surface to cause the upper sleeve to be pressed down against the force of the coiled spring.