GB2061890A - Fuel tank cap, especially for motor bicycles - Google Patents

Abstract

A fuel tank cap, especially for motor bicycles, comprises a main body 10 having a plurality of peripherally spaced resilient members such as member 29, which can be expanded to engage the inner surface of a filler neck by inserting therebetween a frustoconical portion of a member 32 mounted for axial movement in the main body 10 against the action of a spring 45. A latch member 52 is mounted for transverse movement in the member 32 and under the action of a spring 64 engages below an abutment 60 on the main body 10 to retain the movable member 32 in the position for expanding the resilient members. The latch member 52 can be retracted by actuation of a key-operated barrel lock 46 to release the movable member 32. <IMAGE>

Description

SPECIFICATION Fuel tank cap, especially for motor bicycles This invention relates to a fuel tank cap of the type to be applied by pressure, especially for motor bicycles, for closing filler necks formed of a smooth tube without threads or bayonet coupling lugs.

Although most motor vehicles such as motorcars and motorcycles have filler necks provided with retaining means such as threads or external or internal lugs for engagement with the filler cap there are still some filler necks which are completely smooth, i.e. without any retaining means, particularly those for motor bicycles but also for other purposes.

For closing such smooth filler necks conventionally filler plugs are used which are provided with frictional attachment means such as annular rubber expansion plugs which expand and thereby exert pressure against the inner wall of the filler neck under the action of a knob or key arranged on the outer cover of the plug. This type of plug therefore requires the provision of a fixed crown-shaped member to be held in one hand after inserting the plug in the filler neck and a movable member to be actuated with the other hand by means of a knob or key to cause the expansion of the rubber pad or plug.

Therefore, these prior filler plugs have the disadvantage that they necessitate the use of both hands for inserting the plug.

Another disadvantage of these prior filler plugs is that the adhesion of the annular rubber expansion pad to the filler neck in the closed position of the plug is not sufficient to prevent removal of the plug when a sufficiently vigorous pulling force is exerted thereon which would abrade or tear the rubber pad.

A further disadvantage of these prior filler plugs is that after expansion of the rubber pad and thus leaving the plug the latter tends to settle down in a position in which it is not completely inserted in the filler neck whereby the adhesion between the sealing gasket and the edge of the filler neck is reduced.

Finally, these conventional filler plugs, especially those having a key, usually are not very adaptable to various diameters of the filler neck. In fact, when the filler plug is provided with a key, the width of the angle of rotation of the key in the plug cannot easily be varied to vary the degree of expansion of the resilient pad.

It is therefore an object of the present invention to overcome the above-mentioned disadvantages and to provide a substantially universally applicable fuel tank cap for closing smooth filler necks, which cannot be easily removed from the filler neck by unauthorized persons and can be inserted and brought into the closed position on the filler neck with only one hand without need of adjustments and, as it were, completely automatically.

It is another object of the present invention to provide such a fuel tank cap which can be adapted to a wide range of internal diameters of filler necks without substantially changing its construction.

To achieve these and other objects and advantages, which will become apparent from the following description, the invention provides a fuel tank cap of the type to be applied by pressure, especially for motor bicycles, which is characterized by a main body having an annular flange provided with a sealing gasket for engaging the edge of a filler neck and having a central projecting portion provided with a plurality of annularly peripherally spaced resilient horns each having a rearwardly bent root portion extending substantially parallel to the axis of the cap and an outwardly bent distal portion, a movable member mounted for axial movement in the main body and comprising means, for example a frustoconical end portion, for expanding the root portions of said resilient horns as said movable member is moved toward the inner end of the cap against the action of resilient means acting between said main body and said movable member, and a latch member mounted for transverse movement within said movable member and provided with resilient means for pushing it under and in engagement with an abutment on said main body, said latch member being retractable by rotation of a rotatable member.

A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a side view of a fuel tank cap according to the invention; Figure 2 is an axial section taken on the line ll-ll of Fig. 1, and Figure 3 is a transverse section taken on the line Ill-Ill of Fig. 1.

Referring now to the drawings and more particularly to Fig. 2, a fuel tank cap according to the preferred embodiment of the invention comprises a main body 10 provided with an annular flange 1 2 to which a sealing gasket 1 6 is secured by cramping lugs 14 for sealingly attaching the cap to the edge of a filler neck (not shown). The main body 10 has an inwardly hollow, forwardly projecting portion 1 8 provided with three peripheral slots 20, 22 and 23 spaced at 120 from one another.

Provided in the forward end 1 8 of the main body 10 is a tapped axial hole threadably receiving a screw 24 for retaining a resilient metal member 26 having three horns 25, 27, 29 corresponding to the three slots 20, 22 and 23. Each of these horns has a root portion 28, which is bent back toward the flange 1 2 and in the inoperative position of the cap extends substantially parallel to the axis of the main body 10, an outwardly bent distal portion 30 and an intermediate portion of arbitrary configuration. In Fig. 2 the inoperative position of the horn 29 with its root portion 28 and distal portion 30 is shown in solid lines wheres the operative position thereof, which will be described in greater detail hereinafter, is shown in dash-and-dot lines.

A movable member 32 preferably made of metal is slidably received in an axial recess of the main body 10 and an outer cover 36, which may have any desired shape, is secured, preferably by means of rivets 34, to the outer end of this movable member 32 which has a substantially cylindrical shape with three radially upwardly expanding por tions 38, 40, 42 corresponding to the three slots 20, 22 and 23 in the main body and received therein. The end of the movable member 32 opposed to the cover 36 has a frustoconical shape. A tapered spiral spring 45 is inserted under pressure between the flange 1 2 of the main body 10 and the cover 36 secured to the movable member 32 to resiliently hold the latter away from the main body.

The movable member 32 is hollow inside to receive a lock barrel 46 which can be actuated by a key to shift a pin 48 projecting from the end of the barrel and placed eccentrically relative to the axis of the cap. The movable member 32 further has a transverse guideway 50 for slidably receiving a latch member 52 subjected to the action of a helical spring 54.

The latch member 52 has a substantially rectangular recess 56 for receiving the pin 48 on the lock barrel 46.

The latch member 52 normally engages below an abutment 58 on the main body 10, but when the movable member 32 is pressed against the main body 10 against the pressure exerted by the tapered spiral spring 45, the movable member 32 can move by a distance of about 4 mm to engage the latch member 52 below an abutment 60 on the main body 10. The movable member 32 will then be in the position shown by dash-and-dot lines in Fig. 2 and indicated by 62 in which the radiaily expanding portions 38, 40, 42 have moved the resilient horns 25, 27, 29 outwardly to the position indicated by 64 in which the end of the distal portions 30 engages the inner wall of the filler neck (not shown).This sudden movement of the latch member below the abutment 60 can only take place in a certain position of the pin 48 corresponding to a given orientation of the key in the lock. The retraction of the latch member 52 from the abutment 60 and its return movement to the abutment 58 can only take place after an appropriate rotation of the key in the lock to rotate the pin 48 and move the latch member 52 back against the action of the spring 54. Only in this manner the movable member 32 can be moved back to its inoperative position in which the resilient horns 25, 27, 29 are retracted.

It will thus be evident that the described filler cap can be secured in the closed position on the filler neck by actuating the lock to move the pin 48 into a predetermined position in which the latch member 52 can move freely to the left in Fig. 2. Then the cap is applied to the edge of the filler neck with the sealing gasket 1 6 thereagainst and the cover 36 is pressed down to move the movable member 32 relative to the main body 10 until the latch member 52 will snap into position below the abutment 60. In this position the free ends of the resilient horns 25, 27, 29 will engage the inner wall of the filler neck and keep the cap firmly anchored thereto.Any attempt of unauthorized removal of the filler cap is bound to fail because any movement, however slight, of the cap in the direction of its withdrawal from the filler neck can but increase the decree of expansion of the resilient horns and their grip on the inner wall of the filler neck. The ends of the resilient horns are preferably left coarse and unfinished to increase the grip.

When the key is then again inserted into the lock 46 and rotated to move the latch member 52 to the right in Fig. 2, the resilient horns will return in their operative position to release the filler cap.

The screw 24 by which the resilient member 26 is secured in position permits the inoperative position of the resilient horns to be adjusted to vary the degree of final expansion of the horns so as to adapt the cap to various inside diameters of filler necks. A wider range of adjustment can be obtained by replacing only the resilient member 26 by another one of different size or configuration without changing the remaining components of the cap.

An additional advantage of the filler cap described above consists in that it can easily be assembled as the latch member 52 also serves as a connecting member for keeping the cap in the assembled condition. In fact, the cap can be assembled by inserting the movable member 32 into the recess in the main body 10 until the bevelled surface 68 (Fig. 2) of the latch member 52 engages the outwardly obliquely widening portion 66 of the main body 10. By further pressing down the movable member 32, the outwardly obliquely widening portion 66 of the main body 10 will urge the latch member 52 inwardly, permitting the movable member 32 to penetrate further into the main body 10 until thelatch member 52 will again snap below the abutment 58 of the main body 10 whereupon the cap will be completely assembled.

Obviously, in the filler cap described above, the lock may also be replaced by a control knob.

Claims (6)

1. A fuel tank cap of the type to be applied by pressure, especially for motor bicycles, characterized by a main body having an annular flange provided with a sealing gasket for engaging the edge of a filler neck and having a central projecting portion provided with a plurality of annularly peripherally spaced resilient horns each having a rearwardly bent root portion extending substantially parallel to the axis of the cap and an outwardly bent distal portion, a movable member mounted for axial movement in the main body and comprising means for expanding the root portions of said resilient horns as said movable member is moved toward the inner end of the cap against the action of resilient means acting between said main body and said movable member, and a latch member mounted for transverse movement within said movable member and provided with resilient means for pushing it under and in engagement with an abutment on said main body, said latch member being retractable by rotation of a rotatable member.

2. A fuel tank cap as claimed in claim 1, characterized in that said resilient horns are three horns equidistantly spaced peripherally around the axis of the cap.

3. A fuel tank cap as claimed in claim 1 or 2, characterized in that said resilient horns are formed integrally and retained in position by a screw screwed axially into the forward inner end of said main body.

4. A fuel tank cap as claimed in any of the preceding claims, characterized in that said rotatable member for retraction of said latch member is a pin mounted eccentrically on a lock barrel located in an axial recess in said movable member and said pin engages in a recess in said latch member.

5. A fuel tank cap as claimed in any of the preceding claims, characterized in that the means for expanding the root portions of said resilient horns comprises a frustoconical end portion of said movable member.

6. A fuel tank cap constructed and arranged substantially as herein described with reference to, and as illustrated in, the accompanying drawings.