GB1580436A

GB1580436A - Closure caps

Info

Publication number: GB1580436A
Application number: GB2375576A
Authority: GB
Original assignee: AUTO SECURITY PROD
Current assignee: AUTO SECURITY PROD
Priority date: 1976-06-09
Filing date: 1976-06-09
Publication date: 1980-12-03

Description

(54) IMPROVEMENTS RELATING TO CLOSURE GAPS (71) We, AUTO SECURITY PRODUCTS LIMITED, a British Company, of Dawley Brook Trading Estate, Stallings Lane, Kingswinford, Brierly Hill, West Midlands DY6 7AP, formerly of Church Street, Willenhall, West Midlands WV13 lQW, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a closure cap of the kind, hereinafter called the "kind specified", having a closure portion adapted to engage and to seal to a member defining an opening which is to be closed by the cap (which member is hereinafter called the "filler neck"), and retaining means engageable with a formation or formations on the filler neck to retain the cap thereon.The invention has been developed primarily in relation to a cap for the filler neck of a motor vehicle fuel tank.

One form of filler neck which is commonly found on motor vehicles is of generally cylindrical form, terminating in an inwardly turned annular portion which defines the opening and which is connected to the cylindrical part by a radiused portion. The retaining means usually comprises circumferentially spaced lugs provided on a part of the cap, which when the cap is being fitted are passed through gaps in the annular portion and subsequently, upon angular movement, engaged beneath the annular portion e.g. beneath an inturned lip of the annular portion or ramps formed thereunder.

Current and impending regulations impose very severe requirements on the prevention of leakage of fuel from vehicle tanks, and in general hitherto such leakage has been prevented by the provision of an annular sealing member on the cap which engages with the inwardly turned annular portion of the filler neck. However, such a sealing arrangement is not always satisfactory since the sealing member engages the annular portion of the filler neck over a relatively large area resulting in a low engagement pressure between the sealing member and filler neck. Further, the annular portion of the filler neck is interrupted by the gaps through which the lugs forming the retaining means on the cap are required to pass, which gives rise to potential leakage points.

It is an object of the present invention to provide a closure cap in which these disadvantages are overcome or reduced.

According to the invention, we provide a closure cap of the kind specified wherein the closure portion of the cap includes a ring of resilient material and a backing member having a portion which presents an annular surface engaged with one face of the ring, at least said portion of the backing member being more rigid than the ring, said portion of the backing member being of plate-like form, as hereinafter defined, and at least a part of said surface which extends completely around an axis of the closure portion being inclined to the axis, wherein the retaining means is arranged to lie within and engage the interior of the filler neck when the cap is fitted thereon and wherein the ring extends further from the axis than does the retaining means.

By the description "plate-like form" we mean that the thickness of said portion of the backing member, that is the dimension measured in a direction parallel to the axis of the closure portion, is less than the width, that is the dimension measured in a direction perpendicular to the axis, of the annular surface of the backing member which is engaged by the ring. This portion of the backing member is preferably a radially outwardly projecting flange.

At least that part of the ring which overlies the inclined part of the annular surface may be and preferably the entire ring is of substantially uniform thickness. The portion of the backing member which presents the annular surface is also preferably of substantially uniform thickness.

We further provide according to the invention a motor vehicle comprising a fuel tank having a filler neck and a closure cap according to the invention fitted on the filler neck, the filler neck having a radiused portion between a substantially cylindrical portion and a substantially annular portion and the radiused portion being engaged by a part of the ring which overlies the inclined part of the annular surface of the backing member.

This arrangement provides for a greater contact pressure between the ring and the filler neck than would be established if the seal is pressed against the entire annular surface of the filler neck.

The invention will now be described by way of example with reference to the accompanying drawings, of which: Figure 1 shows, partly in cross section, a filler cap in accordance with the invention fitted on a filler neck.

The filler neck, only a small part of which is shown in the accompanying drawing, includes a cylindrical portion 11, and an inwardly turned annular portion 12 connected to the cylindrical portion 11 by way of a radiused portion 13. The portion 12 is formed with two gaps 14 disposed diametrically opposite one another and through which retaining lugs of the closure cap can be passed when the cap is to be fitted to the filler neck.

The cap itself comprises a closure portion 15 which, when the cap is applied to the filler neck, extends over the open end of the filler neck. The closure portion 15 includes a metal body 16 of generally annular form, with an outwardly extending flange 17 of plate-like form. A housing 18 has a spigot 19 which extends through the centre of the body 16 for rotation relative thereto, sealing between the body 16 and housing 18 being effected by an O-ring seal 20. The housing 18 is formed with a ridge 21 which is capable of being grasped by a user for turning the housing.

Axially moveable on the spigot 19, but prevented from rotating relative thereto, is a retaining member 22 of generally annular form which is provided with two diametrically-opposed lugs 23. A retaining plate 24 is arranged on the free end of spigot 19, and secured thereto by a screw 25, and a coiled compression spring 26 is supported between the plate 24 and retaining member 22 so that the latter is biased in a direction towards the housing 18. When the closure cap is positioned on the filler neck, the lugs 23 having been passed through the gaps 14 and the housing 18 having been moved angularly so that the lugs engage beneath the annular portion 12 of the filler neck, the spring 26 is compressed so that the housing 18 and the body 16 and associated components are held against the end of the filler neck by spring pressure.

Within the body 16 there are provided two cavities 27 which open in opposite directions axially of the closure cap and accommodate valve members 28. The valve members 28 are biased against seatings around apertures 29 by compression springs 30 reacting against annular closure members 31 which are secured in the open ends of the cavities, the cavities being capable of communicating with the open atmosphere by way of an annular recess 32 in the housing 18. These valves provide for controlled venting to atmosphere of the fuel tank, the uppermost valve of Figure 1 permitting air to enter the tank if vacuum therein should exceed a predetermined value (e.g. 6 inches of water), and the lowermost valve releases air from the tank to atmosphere should the pressure within the tank exceed a predetermined value (e.g. 1.5 pounds per square inch to 2.0 pounds per square inch).

So that the control of venting of the tank should be exercised by these valves alone, it is required that no leakage from the tank by other routes is permitted, and to this end a sealing ring 33 is provided on the body 16.

This sealing ring is formed of a resilient rubber compound, and the flange 17 provides an annular backing surface for the ring so that sealing can take place against the filler neck 10. The sealing ring 33 is held on or close to the flange 17 by an annular rib 36 on the retaining member 22. The sealing ring 33 and backing member 17 are provided with frusto-conical faces 34, 35 respectively, so that the sealing ring engages the filler neck 10 around a circle on the latter's radiused portion 13. Under the action of spring 26, the sealing ring is compressed between the backing member 17 and the portion 13 of the filler neck, so that sealing is established under a relatively high contact pressure, thereby reducing the possibility of leakage compared to that which would exist if sealing were effective over a relatively larger surface area.

WHAT WE CLAIM IS:- 1. A closure cap of the kind specified wherein the closure portion of the cap includes a ring of resilient material and a backing member having a portion which presents an annular surface engaged with one face of the ring, at least said portion of the backing member being more rigid than the ring, said portion of the backing member being of plate-like form, as hereinbefore defined, and at least a part of said surface vrlqich extends comnletelv around an axis of the closure portion being inclined to the axis, wherein the retaining means is arranged to lie within and engage the interior of the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. We further provide according to the invention a motor vehicle comprising a fuel tank having a filler neck and a closure cap according to the invention fitted on the filler neck, the filler neck having a radiused portion between a substantially cylindrical portion and a substantially annular portion and the radiused portion being engaged by a part of the ring which overlies the inclined part of the annular surface of the backing member. This arrangement provides for a greater contact pressure between the ring and the filler neck than would be established if the seal is pressed against the entire annular surface of the filler neck. The invention will now be described by way of example with reference to the accompanying drawings, of which: Figure 1 shows, partly in cross section, a filler cap in accordance with the invention fitted on a filler neck. The filler neck, only a small part of which is shown in the accompanying drawing, includes a cylindrical portion 11, and an inwardly turned annular portion 12 connected to the cylindrical portion 11 by way of a radiused portion 13. The portion 12 is formed with two gaps 14 disposed diametrically opposite one another and through which retaining lugs of the closure cap can be passed when the cap is to be fitted to the filler neck. The cap itself comprises a closure portion 15 which, when the cap is applied to the filler neck, extends over the open end of the filler neck. The closure portion 15 includes a metal body 16 of generally annular form, with an outwardly extending flange 17 of plate-like form. A housing 18 has a spigot 19 which extends through the centre of the body 16 for rotation relative thereto, sealing between the body 16 and housing 18 being effected by an O-ring seal 20. The housing 18 is formed with a ridge 21 which is capable of being grasped by a user for turning the housing. Axially moveable on the spigot 19, but prevented from rotating relative thereto, is a retaining member 22 of generally annular form which is provided with two diametrically-opposed lugs 23. A retaining plate 24 is arranged on the free end of spigot 19, and secured thereto by a screw 25, and a coiled compression spring 26 is supported between the plate 24 and retaining member 22 so that the latter is biased in a direction towards the housing 18. When the closure cap is positioned on the filler neck, the lugs 23 having been passed through the gaps 14 and the housing 18 having been moved angularly so that the lugs engage beneath the annular portion 12 of the filler neck, the spring 26 is compressed so that the housing 18 and the body 16 and associated components are held against the end of the filler neck by spring pressure. Within the body 16 there are provided two cavities 27 which open in opposite directions axially of the closure cap and accommodate valve members 28. The valve members 28 are biased against seatings around apertures 29 by compression springs 30 reacting against annular closure members 31 which are secured in the open ends of the cavities, the cavities being capable of communicating with the open atmosphere by way of an annular recess 32 in the housing 18. These valves provide for controlled venting to atmosphere of the fuel tank, the uppermost valve of Figure 1 permitting air to enter the tank if vacuum therein should exceed a predetermined value (e.g. 6 inches of water), and the lowermost valve releases air from the tank to atmosphere should the pressure within the tank exceed a predetermined value (e.g. 1.5 pounds per square inch to 2.0 pounds per square inch). So that the control of venting of the tank should be exercised by these valves alone, it is required that no leakage from the tank by other routes is permitted, and to this end a sealing ring 33 is provided on the body 16. This sealing ring is formed of a resilient rubber compound, and the flange 17 provides an annular backing surface for the ring so that sealing can take place against the filler neck 10. The sealing ring 33 is held on or close to the flange 17 by an annular rib 36 on the retaining member 22. The sealing ring 33 and backing member 17 are provided with frusto-conical faces 34, 35 respectively, so that the sealing ring engages the filler neck 10 around a circle on the latter's radiused portion 13. Under the action of spring 26, the sealing ring is compressed between the backing member 17 and the portion 13 of the filler neck, so that sealing is established under a relatively high contact pressure, thereby reducing the possibility of leakage compared to that which would exist if sealing were effective over a relatively larger surface area. WHAT WE CLAIM IS:-

1. A closure cap of the kind specified wherein the closure portion of the cap includes a ring of resilient material and a backing member having a portion which presents an annular surface engaged with one face of the ring, at least said portion of the backing member being more rigid than the ring, said portion of the backing member being of plate-like form, as hereinbefore defined, and at least a part of said surface vrlqich extends comnletelv around an axis of the closure portion being inclined to the axis, wherein the retaining means is arranged to lie within and engage the interior of the

filler neck when the cap is fitted thereon and wherein the ring extends further from the axis than does the retaining means.

2. A closure cap according to Claim 1 wherein said portion of the backing member is a radially outwardly projecting flange.

3. A closure cap according to Claim 1 or Claim 2 wherein said part of the annular surface is frustoconical.

4. A closure cap according to any preceding claim wherein at least a part of the ring which overlies said inclined part of the annular surface is of substantially uniform thickness.

5. A closure cap substantially as herein described with reference to and as shown in the accompanying drawings.

6. A motor vehicle comprising a fuel tank having a filler neck and a closure cap according to any preceding claim fitted on the filler neck, the filler neck having a radiused portion between a substantially cylindrical portion and a substantially annular portion and the radiused portion being engaged by a part of the ring which overlies the inclined part of the annular surface of the backing member.