Fuel Sender Locking Ring

The present invention relates to automotive fuel delivery systems and, in particular, to an improved locking ring for locking a fuel sender assembly to a fuel tank.

Conventional automotive fuel sending systems typically include a locking ring for securely mounting and sealing a fuel sender assembly to a fuel tank. Commonly, the locking ring is provided with lug supports along its outer peripheral edge which lockingly engage retaining lugs extending from the fuel tank for sealing the fuel sender assembly therebetween. Such systems are designed to permit a predetermined amount of fuel leakage and venting of fumes immediately upon impact to relieve any excessive pressure build-up within the fuel tank. However, it is critical that the fluid-tight seal between the fuel sender assembly and the fuel tank be maintained following venting of a pressure build-up to prevent excessive fuel and vapor leakage. In particular, a primary reason for premature release of fuel and fumes upon vehicular impact is the failure of the locking ring to withstand the increased tank pressure. The increased tank pressure acting on the fuel sender assembly and locking ring can cause permanent deformation of the retaining lugs. Structural deformation of the retaining lugs results in degradation of the seal between the fuel sender assembly and the fuel tank. Furthermore, with the advent of stricter vehicle safety standards, conventional fuel delivery systems are inadequate to meet minimum crashworthiness requirements.

It is therefore an object of the present invention to provide a relatively simple and inexpensive design for an improved locking ring for use in automotive fuel delivery systems. The improved locking ring can withstand substantially greater fuel tank pressures following vehicular impact so as to inhibit premature leakage of fuel and vapors. The improved locking ring inhibits permanent deformation of the fuel tank retaining lugs to maintain the fuel sender assembly in sealed relationship with the fuel tank.

Other advantages and features will become apparent from the following specification taken in connection with the accompanying drawings.

FIG. 1 is a perspective view of a conventional fuel sender locking ring;

FIG. 2 is a partial top view of a conventional fuel tank assembly illustrating the operational relationship of the several components;

FIG. 3 is a cross-sectional view taken along line A--A of FIG. 2;

FIG. 4 is a perspective view of an improved fuel sender locking ring according to a first preferred embodiment of the present invention;

FIG. 5 is a partial top view of a fuel tank assembly incorporating the fuel sender locking ring of FIG. 4 and illustrating the operational association of the components;

FIG. 6 is a cross-sectional view taken along line B--B of FIG. 5;

FIG. 7 is a partial top view of a fuel tank assembly incorporating a fuel sender locking ring according to a second preferred embodiment; and

FIG. 8 is a cross-sectional view taken along line C--C of FIG. 7.

Referring now to the drawings, FIGS. 1 through 3 illustrate a conventional fuel sender locking ring 10 for use with a fuel tank assembly 12. Locking ring 10 is employed to secure a fuel sender assembly 14 to fuel tank assembly 12. More particularly, fuel tank assembly 12 comprises a fuel tank 16 having a generally circular opening or aperture 18 through which a lower portion of fuel sender assembly 14 extends. In this manner, various components (not shown) of fuel sender assembly 14 are oriented to partially extend into an internal pressurized chamber 20 of fuel tank 16. Fuel tank 16 has a substantially planar external surface 21 which is generally perpendicular to the axis of aperture 18. An annular groove 22 is provided in external surface 21 which is concentric with the central axis of aperture 18 and which is located radially outward thereof.

Fuel tank assembly 12 further includes means for semi-permanently securing locking ring 10 to fuel tank 16. This includes a plurality of evenly spaced retaining lugs 24 located radially outward of, and concentric with groove 22. Preferably, the arcuate-shaped retaining lugs 24 are disposed around the circumference of groove 22 and have a first leg 26 extending transversely to the planar external surface 21 of fuel tank 16. A second leg 28 is provided which extends radially inwardly from first leg 26 and is generally parallel to planar external surface 21, so as to generally define an inverted "L-shaped" configuration for retaining lugs 24. Preferably, retaining lugs 24 are integral extensions of a ring 30 permanently encapsulated into fuel tank 16. Further, it is preferable that fuel tank 16 be fabricated from a thermoplastic material into which encapsulated ring 30 is permanently secured during the molding process. Such processing could include blow-molding or rotational-molding for the tank fabrication. Again, however, it is within the scope of this invention that the tank 16 be fabricated from any suitable material applicable for pressurized vessels. Likewise, it is contemplated that ring 30 can be secured directly to planar surface 21 via conventional bonding or welding methods.

Locking ring 10 is provided with a central aperture 32 through which an upper portion of fuel sender assembly 14 passes. This allows connection of external fuel delivery and exhaust lines 33 and electrical connectors 35. An axially extending rim 34 provided on locking ring 10 surrounds the upper portion of sender assembly 14. At its outermost peripheral edge surface, locking ring 10 is provided with a plurality of radially outwardly extending lug supports 36. The number and angular spacing of lug supports 36 preferably corresponds directly to the number and angular spacing of retaining lugs 24. As illustrated in FIGS. 2 and 3, each lug support 36 is configured to be received into an "L-shaped" retaining lug 24 upon rotation of locking ring 10 into a locked position. Lug supports 36 have an upstanding tab stop 38 at one end. Tab stops 38 have a greater height than first leg 26 of retaining lug 24 so as to positively locate each lug support 36 relative to a retaining lug 24 during clockwise rotation of locking ring 10 into a locked position. Further, lug supports 36 are provided with a centralized upwardly extending locking nub 40 configured to be lockingly received in a similarly shaped cavity 42 provided in second leg 28 of retaining lugs 24.

In practice, the engagement of locking nubs 40 in cavities 42 combined with the abutting contact of tab stops 38 with a circumferential edge of second leg 28 act to sealingly lock sender assembly 14 to fuel tank 16. Further, a seal member 44 placed in groove 22 is compressed by the locking relationship of the above described components to generate a fluid-tight seal therebetween so as to prevent unintended leakage of fuel liquids and fumes.

However, during vehicular accidents in which the fuel tank is dented or otherwise deformed, or in roll-over situations, excessive pressure within fuel tank 16 is generated which urges sender plate 45 of fuel sender assembly 12 and locking ring 10 to deform in a concave fashion. Such deformation plastically deforms retaining lugs 24 in a radially outward direction such that seal member 44 becomes improperly seated within groove 22. As such, premature and excessive leakage of fuel from the tank occurs. As is well recognized, leakage of fuel is extremely dangerous since it creates a significant fire and explosive hazard. Conventional systems, similar to that herebefore described, experience seal loss at relatively low tank pressures which are unacceptable in light of current government automotive crashworthiness standards.

Referring now to FIGS. 4 through 6, a first preferred embodiment of the present invention is disclosed. For the sake of uniformity, like numbers are used for common components previously described. FIG. 4 illustrates a fuel sender locking ring 100 having a central aperture 32 and rim 34. Preferably, locking ring 100 is fabricated as a relatively thin gauge sheet metal stamping. At its outermost peripheral edge, locking ring 100 is provided with a plurality of radially outwardly extending lug supports 102. Lug supports 102 include a slot-like arcuate opening 104 extending from one end thereof. The opening 104 defines an inner flange section 106 and an outer flange section 108. Inner flange section 106 includes a centralized portion upon which an upwardly cold-deformed protrusion is provided to define an integral locking surface 110. Locking surface 110 is configured to be lockingly captured in cavity 42 of second leg 28 provided on "L-shaped" retaining lug 24. Outer flange section 108 surrounds an outer surface 27 of first leg 26 of retaining lug 24. Preferably, the width of slot-like opening 104 is dimensioned such that outer surface 27 of first leg 26 and outer flange section 108 are in abutting line contacting along generally the entire length of slot-like opening 104. In this manner, outer flange section 108 inhibits the radially outward "bulging" of retaining lugs 24 upon increased pressure within fuel tank 16. However, it is contemplated that slot-like opening 104 can have a width which does not produce contact between outer surface 27 and outer flange section 108 until a limited predetermined amount of bulging has occurred. In either case, seal element 44 will be maintained in a properly seated position within groove 22. Substantially greater internal fluid pressures are therefore possible following vehicular impact without the danger of excessive leakage of fuel and fumes.

Referring now to FIGS. 7 and 8, a second preferred embodiment of the present invention is disclosed. Locking ring 200 is identical to that of locking ring 100 previously described except for the addition of down-turned support members 202 provided as a flange along the peripheral edge of locking ring 200. Support members 202 have an end portion 204 which, preferably, rests on external surface 21 of fuel tank 16. Support members 202 supplement outer flange 108 in resisting deformation ("bulging") of retaining lugs 24. Therefore, sender plate 45 and locking ring 200 are not permitted to prematurely distort and/or yield due to pressures acting thereon so as to prevent the release of fuel tank fumes and liquids.

It is contemplated that the improved locking ring structures disclosed above can be used in any application requiring means for creating a pressurized fluid-tight seal between a cap-like member and a pressurizable vessel which is capable of withstanding substantially greater fluid pressure build-ups.

An improved locking ring for lockingly securing and sealing a fuel sender assembly to a fuel tank is described above. Those skilled in the art will appreciate that other advantages can be obtained from the use of this invention and that modifications can be made without departing from the true spirit of the invention. Furthermore, the foregoing description of the preferred embodiments according to the present invention are provided for the purpose of illustration only and not for purposes of limitation--the invention being defined by the claims.