Land vehicles – Wheeled – Occupant propelled type
Reexamination Certificate
1999-08-13
2001-10-23
Johnson, Brian L. (Department: 3618)
Land vehicles
Wheeled
Occupant propelled type
C280S276000
Reexamination Certificate
active
06305704
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to the front telescopic forks for bicycles, particularly to the forks provided with parallel outer sliding tubes attached at their bottom to the axle of the wheel and inside which there are telescopically movable inner sliding tubes which are interconnected at the top by the so-called crown which carries on its top and median portion the steering tube. Elastic means and shock absorbers are arranged inside the unit formed by the outer and inner sliding tubes, in order to compensate the stresses to which the fork is subjected. In these forks, the upper ends of the outer sliding tubes are usually interconnected by a cross member having the shape of an inverted “U”, which has the function of maintaining parallel the outer sliding tubes, of avoiding torsion (twisting) movements to the fork and which, when the bicycle is provided with a brake acting onto the wheel rim, provides also to support the extremity of the sheath for the wire acting on the brake.
In order to secure the cross member to the outer sliding tubes, presently there are various solutions. One solution consists for example in the pressure coupling of the upper ends of the outer sliding tubes inside the end bushings of the cross member. This solution presents the disadvantage that in order to ensure a perfect parallelism between the outer sliding tubes, it requires very expensive machining operations at the machine tools, inasmuch as the pieces to be coupled together must present extremely precise dimensions.
Another known solution consists in securing the cross member to the outer sliding tubes by means of welding. This solution, if on one hand requires a working of limited precision and not expensive, on the other hand can cause deformation to the outer sliding tubes which could in the long run prejudice their operation.
It is known also the solution proposed in the U.S. Pat. No. 5,635,007 which provides for the realization of the end bushings of the cross member and of the upper ends of the fork by means of mechanical working of scarce precision and which contemplates to secure the two parts reciprocally by means of a structural adhesive for example by means of an epoxy adhesive. This solution, if on one hand simplifies the phase of working of the pieces to be secured, on the other hand leads to complications in the assembly phase of the pieces themselves, which must be arranged onto a reference template in-order to provide that the bushings of the cross member be perfectly aligned with the outer sliding tubes and the presence of the template is required until the adhesive is hardened. It is evident that these phases of mounting and dismounting of the template necessarily complicate the production cycle of the fork and increase its final cost.
SUMMARY OF THE INVENTION
The invention proposes a bicycle fork of simplified construction and of high technological reliability, which contemplates the realization of the cross member with end bushings and the realization of the outer sliding tubes by means of working (machining) of medium precision, and therefore of limited cost and which provides, integral with the bushings of the cross member and with the upper ends of the outer sliding tubes, appendices which when the two above mentioned parts are coupled together, are reciprocally superposed and are arranged so that they can be safely fastened to each other by means of screws. If the fork is intended for a bicycle provided with a brake acting on the rim of the front wheel, the said screws for fastening the cross member to the outer sliding tubes are directed in such a manner and are provided with a projection which can be used as fulcrum for the levers carrying the brake shoes. In order to annul the possible small machining clearance between the inner diameter of the end bushings of the cross member and the outer diameter of the upper ends of the outer sliding tubes, between the two parts there is inserted a small coating of any material which is initially liquid and that subsequently hardens, for example any varnish or resin suitable for this purpose, which can even not present adhesive functions for the reciprocal fastening of the two pieces, inasmuch as the structural fastening is ensured by said appendices and pertaining fastening screws. The bushings of the cross member are arranged with their lower end abutting against a step of the upper end of the outer sliding tubes, thus ensuring the parallelism between the axes of the two parts, while the reciprocal fastening of the said appendices by means of the screws provides for the reciprocal alignment of the axes of the two parts and provides that the axes of the two outer sliding tubes be arranged at a predetermined reciprocal distance, maintaining the whole in the correct position, without the need of alignment templates as required by the known prior art. This precision will be also maintained during the use of the fork, thanks to the hardened resin which annuls the small clearances due to the machining tolerances between the coupled parts of the outer sliding tubes and of the cross member.
REFERENCES:
patent: 4775163 (1988-10-01), McGowan et al.
patent: 5078417 (1992-01-01), Mouritsen
patent: 5478099 (1995-12-01), Kawahara
patent: 5634652 (1997-06-01), Tsai
patent: 7-117773 (1995-05-01), None
Musiani Sandro
Vignocchi Loris
Johnson Brian L.
Lerner Avraham H.
Marzocchi S.p.A.
Ward & Olivo
LandOfFree
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