Machine element or mechanism – Control lever and linkage systems – Elements
Reexamination Certificate
2001-01-11
2002-10-22
Luong, Vinh T. (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Elements
C074S551800
Reexamination Certificate
active
06467372
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a steering device for use on a bicycle. Conventional steering devices are comprised of a bar stem attachable to a head tube and fitted with the basic handlebar.
DESCRIPTION OF THE PRIOR ART
The French document 1 554 438 discloses a configuration which is comprised of a stem bar having a tube-like sleeve for the insertion of the handlebar. The handlebar's ends are fitted with two bar ends providing the rider with a choice of hand positions. Since the stem tube holding the handlebar is rather short, under severe riding conditions, especially when pulling forces are applied to one side of the handlebar, the resulting bending stresses may cause the handlebar to fail from fatigue.
The U.S. Pat. No. 1,595,557 discloses a configuration which is comprised of a handlebar transversely mounted to the stem, the handlebar's ends being fitted with two inserts to which bar ends are pivotally attached. This configuration is not secure against early fatigue failure either.
The German patent application DE-OS 2 659 402 discloses a handlebar having two pivoting grip elements. This configuration also fails to be secure against fatigue failure.
The documents U.S. Pat. No. 5,145,210, U.S. Pat. No. 5,197,350, U.S. Pat. No. 4,750,754, U.S. Pat. No. 5,154,095, WO 91/16231, GB 13 053, and CH 278 827 show clamps for use in a steering device, which can receive two tubes in directions perpendicular to each other. The devices disclosed in these documents fail to be secure against fatigue failure.
The U.S. Pat. No. 289,630 discloses a dual tube clamp for use in a steering device, by which two parallel tubes are receivable. The tubes can be fixed by means of two screws arranged on an axis that is perpendicular to the longitudinal axis of the tubes. One tube is arranged between these screws. This device fails to be secure against fatigue failure.
Document FR 638 790 also shows a dual tube clamp for fixing parallely arranged tubes. The clamp consists of two single parts which are mirror-imaged. A screw being arranged between the two tubes fixes the tubes between these parts. The screw extends in direction perpendicular to the mirror axis and to the tubes' axis with its longitudinal axis. This device also fails to be secure against fatigue failure.
Document CH 101 297 shows a steering device with a clamp for receiving two parallel tubes. Each of the tubes is fixed by means of one screw, the screws being different from each other. This device also fails to be secure against fatigue failure.
The U.S. Pat. No. 5,570,614 discloses a steering device comprising two half handlebar tubes. Each of these half handlebar tubes is received by a bore of a double tube clamp. One screw fixes the half handlebar tubes within the double tube clamp. The bores of the handlebar tubes are arranged parallely to each other. This device also fails to be secure against fatigue failure.
U.S. Pat. No. 4,903,542 shows a steering device with scale marks on the circumference of a handlebar tube. However, this device also fails to be secure against fatigue failure. Moreover, it is state of the art as shown in
FIG. 1
to provide a handlebar transversely installed in a stem with socket at both ends which themselves serve to hold handlebar tubes. This configuration likewise consists of a handlebar being clamped in the stem, and as a result is likely to fail from fatigue. By using extremely wide clamps, the inherent problem can be diminished, but not solved.
Besides, especially wide bar stem clamps are clumsy and an offense to the eye. Another problem arises from the fact that the rider wants to match different types of bar stems and handlebars of a certain size in order to meet his specific needs. With poorly matched components there is always the risk of reduced fatigue resistance. When combining a sharp-edge steel stem with a thin-walled handlebar, the danger of early fatigue failure is increased, even more so if it is an aluminum handlebar.
Therefore, it is the intent of the present invention to provide a bicycle steering device the use of which will help to noticeably reduce the danger of early handlebar fatigue failure as compared to conventional handlebar configurations.
SUMMARY OF THE INVENTION
In accordance with the present invention, the bicycle steering device is comprised of a one-piece T-shaped bar stem attachable to a head tube, having two opposite ends, each end being designed to be fitted with a clamp, the two clamps being used to firmly hold a handlebar tube.
The steering device in accordance with the present invention is considerably more secure against fatigue failure, since the handlebar tube is directly coupled to the bar stem by means of clamps. Adapters subject to wear and fracture are eliminated. In addition, steering precision is improved over conventional configurations. Furthermore, the common mistake of using a poorly matched handlebar/stem combination is prevented, as the conventional handlebar center section clamped in the bar stem is deleted. The embodiment in accordance with the present invention has increased flexural rigidity and can be adjusted to meet ergonomic requirements.
In a favorable embodiment the T-shaped bar stem comprises a third end to which a further clamp is mounted with its first end. The second end of the clamp is fixed at a head tube comprised by a bicycle.
In a favorable embodiment of the present invention the two ends of the bar stem are essentially parallel, and the handlebar tube is straight. Thus, the two ends of the one-piece T-shaped bar stem are assumed to lie on a straight line, the same is assumed for the handlebar tube.
The handlebar tube is fastened essentially parallel to the stem's end sections. This results in improved rigidity and steering precision.
The wall thickness of the handlebar tube according to the invention changes along the longitudinal axis of the handlebar tube, wherein the wall thickness is defined by the difference between an outer radius and an inner radius of the handlebar tube. The inner radius is equal to the distance between the longitudinal axis of the handlebar tube and the inner surface of the handlebar tube and the outer radius is equal to the distance between the longitudinal axis of the handlebar tube and the outer surface of the handlebar.
The handlebar tube of the invention exhibits at least one reinforcement area. This reinforcement area is designed such that the wall thickness of the handlebar tube, which changes along its longitudinal axis, reaches its maximum. The reinforcement areas serve to hold the handlebar tube or the attachment clamps, respectively. Thus, each of the attachment clamps id fixed within a reinforcement area.
A favorable embodiment of the attachment clamp in accordance with the present invention is a socket clamp designed to receive two tubes. It is comprised of two clamp sections, their longitudinal axes being parallel. This type of dual tube clamp costs less to manufacture and saves material.
In a favorable embodiment each of the clamps has two front sides with an outer area. This adds to strength and rigidity.
In a favorable embodiment all clamp sections incorporate one slot each which enables adequate and simultaneous clamping of the two tubes. The attachment clamp comprises one slot and can be clamped by a clamping means so that the width of the slot will be decreased independently from each other when the clamp is fastened. This has the advantage that the fastening of both tubes is possible, if there are minor variances in the diameters of different handlebars or bar stems which can result in industrial production. There are at least one open and one closed position of the clamps wherein in the open position the width of the slot is greater than in the closed position.
In another preferred embodiment the attachment clamp comprise two openings which coincide with the slots of the clamp sections. Also in this embodiment the clamp sections can be fastened by the use of just one clamping means under the advantages mentioned above.
In a favorable embodi
Luong Vinh T.
Ohlandt, Greeley, Ruggeriero & Perle, LLP
Rauchfuss, Jr. George W.
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