US20070039409A1

US20070039409A1 - Pillar stem for aerobar assembly

Info

Publication number: US20070039409A1
Application number: US11/589,839
Authority: US
Inventors: Horizon Garrison Meng
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-06-08
Filing date: 2006-10-31
Publication date: 2007-02-22
Also published as: US7127966B2; US20050268743A1; TWM263295U

Abstract

An aerobar assembly is arranged to be mounted on a pillar stem, rather than on the handlebars, of a bicycle. The pillar stem in turn supports the handlebars. By mounting the aerobar on the stem, the range of adjustability of the aerobar is greatly increased, and the handlebar is subject to less torsional forces. The aerobar assembly includes a pillar stem having one end secured to the stem and a support structure at a second end for mounting an aerobar bracket, an arm rest support, and handlebar clamps. The aerobar bracket is arranged to permit axial adjustment of aerobar position, while the arm rest support is arranged to enable lateral, horizontal pivoting, vertical swivelling, and fore-aft adjustment of arm rest position independent of aerobar position. The handlebar mount preferably uses C-clamps that can easily be substituted to accommodate different handlebar configurations.

Description

This application is a continuation-in-part of U.S. patent application Ser. No. 10/893,361, filed Jul. 19, 2004.

BACKGROUND OF THE INVENTION

1. Field of the Invention
This invention relates to an aerodynamic handlebar extension for bicycles, also known as an “aero bar” or aerobar, and in particular to an aerobar assembly that mounts on the handlebar stem that is part of the frame of the bicycle, rather than on the existing handlebars, and that thereby provides improved adjustability, comfort, and safety.
2. Description of Related Art
The concept of handlebar extensions that permit the rider of a bicycle to assume an improved aerodynamic position, by positioning the rider's hands forwardly of the handlebar and by providing support for the riders elbows or forearms, is well-known. Conceived in the mid-1980's, the aerobar was quickly adopted by triathletes. Since Greg LeMond used them in winning the 1989 Tour de France, aerobars have also attained widespread use by bicycle racers, particularly during time trials.
In competitive cycling, proper fitting or adjustment of the aerobar to the rider is critical to achieving optimal performance. In general, the closer the torso of the rider is to horizontal, the lower the aerodynamic drag on the rider. However, the resulting extension of the lower back and hamstrings in the optimal aerodynamic position may cause injury or discomfort to the rider, and may prevent the rider from achieving maximum power. In addition, proper positioning is necessary to ensure clearance for the rider's knees. As a result, the optimal position for racing or triathlons depends on the physiology of the rider, and can vary substantially from rider to rider.
Most currently available aerobars are either non-adjustable or have at best a limited adjustability. While the aerobars of an adjustable aerobar assembly can usually be moved in a fore-to-aft direction to ensure proper horizontal positioning of the rider and accommodate different arm lengths, the elbow rests or pads can only be adjusted laterally, and fail to take into account skew or angling of the rider's arm, either in a horizontal or vertical plane. Furthermore, because the conventional aerobars are either integral with the handlebars or clamped thereto, possibilities for adjustment are limited by the position and configuration of the handlebars.
On the other hand, many conventional aerobar brackets offer too great a lateral tolerance for the aerobars, because the left and right aerobar brackets are mounted independently on the handlebars. This makes it difficult to position the aerobars symmetrically, in a balanced manner, on the left and right sides of the stem.
Another problem with conventional aerobars is the problem of compatibility. Most conventional aerobars are suitable only for a single type of handlebars. Different types of handlebars, e.g., drop bars or bullhorn style TT bars, require different aerobar designs to ensure proper positioning and clamping of the aerobar, provide access to shift levers if stem mounted, and to ensure clearance between the aerobar mount and the knees of the rider.
In addition to the problems of limited adjustability and compatibility, another problem with conventional aerobars is that they can present a significant safety hazard. The cinch clamps conventionally used to secure an aerobar to the handlebars of a bicycle exert a substantial amount of force on the handlebar, in order to counter the rotational torque exerted when the rider leans on the aerobars. This anti-torsion clamping force, combined with vibrations and road shocks, can cause metal fatigue and cracking of the handlebars, while vibrations and shocks also can cause the bolts that secure the clamp to the handlebars to loosen and permit the aerobars so suddenly become loose or fall off.
Furthermore, because the conventional aerobar handlebar brackets must be positioned so that the brackets and aerobars clear the stem, they enable the aerobars to be slid to a position where they extend behind the fork, in the path of the rider's knees. This can also present a serious safety hazard.

SUMMARY OF THE INVENTION

It is accordingly a first objective of the invention to overcome the drawbacks of the prior art by providing an aerobar having enhanced performance, comfort, safety, and reliability.
It is a second objective of the invention to provide an aerobar that is fully adjustable to enable a rider to assume a position that provides optimal performance during speed racing, and that also provides an optimal balance of speed and comfort during triathlons and other endurance contests.
It is a third objective of the invention to provide an aerobar that is simple in construction and easily mounted on a bicycle.
It is a fourth objective of the invention to provide an aerobar that provides increased safety by eliminating the problems caused by the conventional use of cinch clamps to secure conventional aerobars to handlebars, including cracking of the handlebars and loosening bolts.
It is a fifth objective of the invention to provide an aerobar that can be adapted to any handlebar style, including those in which the handlebars have a non-circular cross-section.
It is a sixth objective of the invention to provide several improvements to and modifications of the aerobar assembly disclosed in the parent application Ser. No. 10/893,361.
These objectives are achieved, in accordance with the principles of a preferred embodiment of the invention, by providing an aerobar system that is arranged to be mounted on the handlebar stem of the bicycle fork, rather than on the handlebars, and that in turn supports the handlebars.
According to an especially preferred embodiment of the invention, the handlebars, aerobars, and arm rests are separately mounted to a pillar stem clamped to the handlebar stem by cap screws that thread directly into the pillar stem without the use of bolts. The bracket/support structures for the aerobars and arms rests permit a variety of independent adjustments of aerobar and arm rest position, including fore-to-aft adjustment of aerobar position, lateral and fore-to-aft adjustment of arm rest position, and adjustment of arm rest angle or skew in both horizontal and vertical planes. The handlebar mount preferably uses C-clamps that can easily be substituted to accommodate different handle bar configurations.
By mounting the aerobar on the stem, the range and ease of adjustability of the aerobars or arm rests may be greatly increased, while still ensuring that the aerobars will be laterally centered and positioned away from the riders knees. In addition, mounting of the aerobars on the handlebar stem of the bicycle fork rather than the handlebars provide a mechanical advantage that prevents torsional forces from cracking the handlebars, while the use of socket or cap screws threaded into a pillar stem to support the arm rests, aerobars, and handlebars eliminate the problem of bolt loosening.
By providing an independent modular support for the aerobars, it is possible to achieve an optimal stem length for positioning the handlebars, without or without the addition of aerobars and arm rests. The pillar stem can initially BE provided solely as a handlebar support, with the aerobars and arm rests offered as an option which can easily be installed, removed, replaced, and/or adjusted at a later time simply by loosening and tightening one or two screws, without such inconveniences as having to remove or re-apply handlebar tape.
Finally, a few further additions and/or modifications of the above-described aerobar may be made, including:

a. The addition of knee bumpers to the rear cinch clamp so as to lessen injuries when a cyclist's knee impacts the clamp.
b. The addition of arc-variable eccentric collars to provide angular adjustment of the stem when attached to a bicycle fork or steering column.
c. The use of titanium bolts or fasteners treated with physical vapor deposition (PVD).
d. The addition of a moisture outlet for the stem's upper utility ports.
e. The addition of a plug gasket for the stem's lower utility ports.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an isometric view of an aerobar assembly constructed in accordance with the principles of a preferred embodiment of the invention.
FIG. 1B is a side view of the aerobar assembly of FIG. 1.
FIG. 2 is an exploded isometric view of a pillar stem for use in the aerobar assembly of FIG. 1.
FIG. 3A is an exploded isometric view of an aerobar bracket sub-assembly for use in the aerobar assembly of FIG. 1.
FIG. 3B is a front view of the aerobar bracket sub-assembly of FIG. 3A.
FIG. 3C is a top view of the aerobar bracket sub-assembly of FIG. 3A, with a modified aerobar configuration.
FIG. 4 is an isometric view of an arm rest sub-assembly for use in the aerobar assembly of FIG. 1.
FIG. 5A is an exploded isometric view of the arm rest sub-assembly of FIG. 4.
FIG. 5B is a front view of the arm rest sub-assembly of FIG. 4 after installation of the handlebars.
FIG. 6 is a cross-sectional front view of the arm rest sub-assembly of FIG. 4, showing lateral adjustment of the arm rests.
FIG. 7 is a side view of the arm rest sub-assembly of FIG. 4, showing pivotal adjustment of an arm rest about the axis of the arm rest support.
FIG. 8 is an isometric view of a handlebar that may be used with the aerobar assembly of FIG. 1.
FIG. 9A is an exploded isometric view of a modified aerobar assembly that incorporates several improvements/modifications including knee bumpers, PVD treated titanium bolts, a moisture outlet for the stem's upper utility ports, and a plug gasket for the stem's lower utility ports.
FIG. 9B is a cross-sectional top view of the cinch clamp portion of the stem of FIG. 9B, showing a knee bumper.
FIG. 10A is an isometric view showing two different stem mounting angles made possible by the use of eccentric collars.
FIG. 10B is an isometric view of a stem and one set of collars.
FIG. 10C is a side view showing the collar of FIG. 10B rotated to different angles.
FIGS. 10D and 10E are side views showing the effects of the various collar angles on the orientation of the stem.
FIG. 10F shows various stem-angle-adjustment collar configurations.
FIG. 10G is an isometric view of an alternative collar configuration.
FIG. 10H is an isometric view of yet another alternative collar configuration.
FIG. 11A is an isometric view of the assembled stem of FIG. 9A.
FIG. 11B is an isometric view of the assembled step of FIG. 9A including bicycle fork and handlebars.
FIG. 12 is an isometric view of the stem of FIG. 9A showing operation of a moisture outlet for the stem's upper utility ports.
FIG. 13 is a cross-sectional side view showing details of a gasket fitted into the stem's lower utility ports.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1A is an isometric view of an aerobar assembly according to a preferred embodiment of the invention, and FIG. 1B is a side view. Various sub-assemblies of the aerobar assembly illustrated in FIGS. 1A and 1B are shown in FIGS. 2-8. FIG. 2 illustrates a pillar stem mount 20 and associated hardware for mounting the aerobar assembly on the handlebar stem of a bicycle, and for securing a handlebar 12 to the aerobar assembly, while FIGS. 3A-3C show a pair of aerobars 32 and a bracket 30 for adjustably mounting the aerobars on the pillar stem mount, FIGS. 4, 5A, 5B, 6, and 7 illustrate the structure and operation of an arm rest sub-assembly 40, and FIG. 8 shows one of many handlebar configurations that may be mounted to the aerobar assembly of FIG. 1.
As illustrated in FIGS. 1A, 1B, and 2, the pillar stem mount 20 is arranged to be mounted on the handlebar stem of a bicycle fork (indicated by dashed lines) by means of a cinch clamp 21. Because the handlebar stem of the bicycle fork typically has a larger diameter than the handlebars, it is better able to withstand clamping, and therefore provides a more secure mount for the aerobar assembly. Furthermore, the pillar stem is subjected by the handlebars to a linear, downwardly directed force that is absorbed by the fork rather than to a torsional force borne by the handlebars, eliminating the problem of metal fatigue and cracking of the handlebars.
It will be appreciated that cinch clamp 21 may be replaced by other types of structures for securing the pillar stem mount to the fork of a bicycle, or the pillar stem may even be made integral with the handlebar, without departing from the scope of the invention. Although not shown, the cinch clamp is typically tightened by screws or bolts extending through openings in the clamp in conventional fashion, and the clamp may rest on the fork into which the pillar stem is inserted.
The main body of the pillar stem is cylindrical and may be hollow or solid, although a hollow configuration is preferred in order to reduce the weight of the assembly. At the opposite end of pillar stem 20 from the cinch clamp 21 is an integral, generally c-shaped supporting structure 22 which has three functions: (i) to support the handlebars; (ii) to support the aerobar bracket; and (iii) to support the arm rest. The pillar stem including the supporting structure 22 at one end are preferably cast or machined as a single piece or member. Each of the handlebars, the aerobar bracket, and the arm rest assembly is independently mounted on the c-shaped supporting structure 22, and therefore independently adjustable.
The supporting structure is illustrated as including a lower pair of threaded openings 225 for mounting the aerobar bracket, an upper pair of threaded openings 224 for mounting the arm rest sub-assembly, and two pairs of frontwardly facing threaded openings 223 for mounting handlebar C-clamps or brackets 23.
Preferably, each sub-assembly is mounted using cap screws or machine screws. The illustrated screws are hex type socket head cap screws, although other types of screws or fasteners may be utilized so long as the screws or other fasteners mount the respective subassemblies to the supporting structure 22 in a secure manner and, where appropriate, in such a way that the mountings can be loosened and the positions of the subassemblies adjusted.
As illustrated in FIGS. 3A-3C, the aerobar bracket 31 preferably includes a pair of openings 311 for receiving aerobars 33 and a central connecting portion in which are located upper and lower pairs of through-holes 312, either or both pairs of which may be threaded or smooth.
Upon insertion of the aerobars to a desired position in the openings 311, the screws 313, which have been extended through openings 312 and threaded into openings 225 in the supporting structure of pillar stem 20 just far enough to avoid stressing the bracket 31, are tightened to cause the bracket to securely clamp and center the aerobars in the openings 311 by causing the lower connecting portion between the openings to be pulled toward the upper opening. To adjust the forward extent of the aerobars 32, screws 313 are simply loosed to a point at which the lower connecting portions is sufficiently far from the upper connecting portion to enable release of the aerobars for movement within the openings 32, after which the screws are tightened to the support 22 of pillar stem 21 to again clamp the aerobars.
Preferably, the bracket positions the aerobars in front of the fork, so that the fork prevents a user from extending the aerobars rearwardly to a position where the rider's knees could come into contact with the aerobars. However, those skilled in the art will appreciate that the invention is not limited to a particular aerobar configuration. For example, alternative aerobar styles are illustrated in FIGS. 3A, 3B, and 3C, the latter having a dual-curved configuration. The invention is intended to be used with any aerobar shape, length, and position.
The arm rest sub-assembly is illustrated in FIGS. 4, 5A, 5B, 6, and 7. Each of the arm plates 42 is adjustably mounted on an elongated, generally tubular or cylindrical arm plate support 41, which is mounted on the top of the pillar stem support structure 22 by two screws 413 arranged to extend through openings 412 in the support 41 and threaded openings 224 at the top of support structure 22.
Preferably, support 41 includes some sort of alignment structure arranged to fit into a complementary alignment structure in the support structure 22. For example, arm rest support 41 is illustrated as including notches or depressions 411 arranged to fit over complementary ridges or projections in the top of the support structure 22 at the end of the pillar stem 21, thereby facilitating lateral alignment of the support 41 and the support structure 22.
Arm rest support 41 includes two hollow sections in which are fitted two cylindrical, transversely-threaded dual-head nuts 415 arranged to slide axially within the support. Each of the threaded openings in each of nuts 415 is arranged to receive a cap screw 41 via slots 414 in support 41 and beveled washers 418. In addition, the cap screws received by nuts 415 respectively extend through openings 422 and 423 in the arm rest plates 42, with one of the pairs of cap screws for each nut extending through opening 422 and the other through opening 423. Openings 422 are circular while openings 423 are curved slots for reasons that will be discussed below in connection with FIG. 7.
The nuts 415 are secured within the support 41 by threaded end caps 416, which may of course take a variety of forms, including press fit rather than threaded caps.
Those skilled in the art will appreciate that nuts 415 are not limited to a dual-head shape, but may be in the form of a single cylinder with two threaded holes, or other shapes to accommodate different arm rest support configurations, including flanges or grooves to facilitate alignment of the threaded openings with the slot 414.
In addition, washers 418, which have a curved lower surface corresponding in shape to the curved surface of support 41 and a counter sink at the top to receive the heads of screws 421, may have a variety of shapes to accommodate different arm rest support and screw head shapes.
When the cap screws are extended through the respective openings in arm rest plates 42, washers 418, and slots 414, they may be threaded into openings 417 to fixedly secure the arm rest plates 42 to the support 414. However, as illustrated in FIG. 6, because slots 414 are longer than the distance between openings 417 in each cylindrical nut 415, as illustrated in FIG. 6, when the cap screws are loosed to permit relative movement between the nut and the support 411, but not sufficiently to separate the cap screws from the openings, the arm rest plates 42 may be slid in a direction parallel to slots 414, and thereby laterally adjusted relative to the support.
In addition, as illustrated in FIG. 7, because the slots 411 are wide enough to permit movement of the cap screws across the width of the slots, i.e., in a tangential direction relative to support 411, and because of the curved lower surface of washers 418, when the cap screws are loosened in the manner described above, the arm rest assemblies can be swivelled or pivoted around the axis of the support so that they tilt upwardly or downwardly, or are horizontal, in accordance with the preference of the rider.
Finally, the skew or angle of the arm rest plate 42 in the horizontal plane, i.e., relative to a substantially vertical pivot, may also be adjusted, upon loosening of the cap screws by an amount sufficient to permit movement between the arm rest plates and support 411 without separating the screws from the threaded openings 417 in nuts 415, by pivoting the arm rest plates around the respective cap screws extending through openings 422, which by their circular nature providing a pivot point. Slots 423 have a curvature that forms a constant radius with the center of openings 422, and thus the slots are capable of sliding relative to the cap screws extending therethrough, allowing the entire arm plate to pivot.
As illustrated, arm rest plates include two circular openings 422 in each arm rest 42, and two slotted openings 423. This permits the fore-to-aft position of the arm rests relative to the support 411 to be adjusted by selectively using either the forwardmost or rearward most one of the slots 422 and 423 as the slots through which cap screws 421 and 422 are extended. This is an optional feature, and it is within the scope of the invention to use a single opening 422 and a single opening 423 in each arm rest plate, or more than two of each type of opening to achieve finer adjustment.
Additional optional features of the arm rest include slots 424 which reduce the weight of the plates and/or provide ventilation. The arm rest plates may be padded (not shown) for further comfort, coated with rubber, plastic, or the like, or even made of a synthetic rather than metal material. Other parts of the aerobar assembly may also be made of metal or other materials, the materials of the various parts forming no part of the present invention.
The final sub-assembly of the aerobar assembly illustrated in FIG. 1 is the handlebar sub-assembly, which consists of a handlebar 10, such as the one illustrated in FIG. 8, and C-clamps or brackets 23. The brackets each include openings 231 for cap screws 232, which are extended through the openings 231 and threaded into openings 223 to secure the handlebar to the pillar stem mount.
This arrangement permits a variety of different handlebar configurations to be used with the aerobar assembly of the invention. For example, the handlebar may correspond to handlebar 10 illustrated in FIG. 8, which is a drop style handlebar having downwardly and inwardly curved drop extensions 12 and an oval base bar 11; i.e., a base bar with an oval cross-section. Numerous other cross-sectional base bar shapes can be accommodated by the illustrated C-clamps, and if a different cross-sectional shape that does not fit the illustrated C-clamps, the C-clamps can be replaced by other clamp configurations, or by a suitably shaped or configured bracket.
FIG. 9A shows an alternative pillar stem 500 that includes several improvements/modifications of the stem illustrated in FIGS. 1-8. The first improvement is the inclusion of knee bumpers 501, also shown in FIG. 9B, that fit over the rear and side portions of cinch clamp 502 for clamping the stem 500 to the fork or steering column 18 (see FIGS. 1B and 2) of the bicycle. The bumpers 501 preferably are molded of a recyclable thermal plastic elastomer, although other cushioning materials may be substituted, and include projections 503 that fit into holes 504 in the cinch clamp 502 to secure the bumpers 501 to the cinch clamp 502. Because the bumpers are made of an elastomeric material, they can be snapped onto and removed from the cinch clamp without tools. The projections 503 are dimensioned to fit into threaded or non-threaded openings in the stem or in the cinch clamp fastener 505, as shown in FIG. 9B, and the shape of the bumpers preferably ensures a snug fit. The purpose of the bumpers is to lessen or prevent injuries such as cuts, lacerations, abrasions, bruises, and breakage whenever a cyclist's knee impacts the cinch clamp.
Also shown in FIG. 9A, and in FIGS. 11A and 11B, are fasteners or bolts 510 for attaching handlebar clamps 511 to the pillar stem 500. Bolts 510, and/or any other fasteners or bolts used to attach various sub-assemblies to the pillar stem, are in this embodiment made of titanium that has been treated with physical vapor deposition (PVD). PVD treated titanium fasteners have previously been used only in aerospace and Fl motorsport applications. In addition to increased hardness, thereby making the threaded shank and non-threaded body less susceptible to stripping or fracturing, the PVD treated stem bolts have a color spectrum coated finish, thereby allowing them to be used as an optional marker for quality control (i.e., good stems will have colored bolts whereas inferior stems will not). The PVD color spectrum coated finish also absorbs the reflective glare from sunlight, in contrast to naturally silver titanium stem bolts which reflect harmful sunlight glare to a rider's eyes, harming vision and reaction time, and permits the vivid detection of fastener cracks or fissures so as to provide early detection of fastener failures. Finally, PVD treated titanium bolts have lower friction loss that makes the bolts less susceptible to galling, freezing, and/or cracking when being torqued during installation, adjustment, or removal.
FIG. 9A also shows a moisture outlet 512 for the upper utility ports 513 of the stem. The upper utility ports 513 may be used to attach the arm rest sub-assembly illustrated in FIGS. 1-8, or other sub-assemblies such as aerobars or lights. However, when upper utility ports 513 are not in use, because the arm rest assembly is not required, dirt or moisture from sweat or rain, represented by drop 514 illustrated in FIG. 12, may fall into and collect in ports 513. To solve this problem, an outlet 512 on each side of the pillar stem communicates with a respective bottom of ports 513 to provide an outlet for moisture (represented by drop 514′). In addition, the outlets provide airflow to carry liquid anodizing solution, allowing the ports to become fully anodized in order to guard against corrosion, and also permit the use of compressed air to blow away unwanted dirt, debris, and moisture.
FIGS. 9A and 13 show a plug gasket 515 that may be used to seal off unwanted dirt, debris, and moisture from the threads and inner body of the stem's lower utility ports 516 when they are not being used, for example to hold an aerobar sub-assembly as illustrated in FIGS. 1-8. The plug gasket 515 is preferably made of a recyclable thermal plastic elastomer (though other materials may be substituted) and includes threaded cylindrical extensions 517 that have sufficient resilience to be pushed past and held by the threads in ports 516 to removably secure the gasket to the pillar stem.
Finally, FIGS. 10A-10H show a collar arrangement for varying the angle of the pillar stem when attached to a bicycle steering column or fork. The collar arrangement, which may be used with or without any of the sub-assemblies illustrated in FIGS. 1-8 or the additional features of FIGS. 9A, 9B and 11-13, allows for an increase or decrease in stem angle to increase rider ergonomics and operating efficiency by permitting the height of the handlebars 12 to be adjusted as illustrated in FIGS. 10A and 10B.
In the embodiment illustrated in FIG. 10B, the collar arrangement includes two complementary collars 520 and 521 each having an eccentric rim 522,523 and a cylindrical body 524,525 extending at a predetermined angle relative to the rim. In addition, a gap 527 bisects the respective rims and bodies so as to enable the collars to be fitted over the fork or steering column 18, and to provide a marker for angular positioning of the collar.
As is best shown in FIG. 10C, as the collars are rotated about a vertical axis, the angle of the cylindrical body 524,525 relative to the vertical axis changes. Reference numerals 520′ and 521′ indicate a first angle of collars 520 and 521; reference numerals 520″ and 521″ indicate a second angle; and reference numerals 520′″ and 521′″ indicate a third angle. As a result, when the collars are fitted over the fork or steering column 18 and the pillar stem 500 is clamped to the bodies 524,525, the angle of the pillar stem varies accordingly, changing the height of the handlebars 12, as indicated in FIG. 10C, which shows the various pillar stem orientations corresponding to the rotational positions indicated by reference numerals 520′,521′, 520″, 522″, and 520′″, 521′″ shown in FIG. 10B. FIG. 10D shows that a downward rather than upward inclination can be achieved simply by exchanging collars 520 and 521.
FIG. 10F shows various alternative configurations 522A,522B,522C of the rim. It will be appreciated that every pair of collars should be engineered to retain the same bearing tension and mounting position of the step onto the fork or steering column tube, but that the collars may otherwise have any geometric shape to fit the weight, durability, and clamping requirements of the stem. The oval design, for example, offers a light weight design with arc modification capabilities. The inner diameter of the collar may of course be varied as necessary to fit the corresponding outer diameter of the fork or steering column, which is typically 28.6 mm for high end forks and 25.4 mm for low end forks, though it is of course within the scope of the invention to modify the collars to fit other types and sizes of fork or steering column.
Whereas the regular handlebar stems only offer the reciprocal of one angle, limiting riders to two angles (upwardly inclined and downwardly inclined), the illustrated collars provide an infinite number of stem angles, to which the pillar stem 500 can be adjusted without removing the handlebar C-clamps. In addition, the collar arrangement offers a taller surface for clamping the stem onto the fork or steering column, thereby increasing the cantilever beam to steering column stiffness and lessening its torsion. The collars can be used to dampen road shock and low vibrations by using different materials, such as carbon, urethane, plastic, allow, and so forth, for adjusting ride feedback. Also, the two-collar design facilitates removal of the stem from the fork by dropping down when the clamp is loosened, exposing the larger inner circumference of the stem to enable the stem to be easily lifted off the fork. Variations of the collars illustrated in FIGS. 10G and 10H including forming the collar of a single cylindrical member 530 for convenient installation, as illustrated in FIG. 10G, or sculpting the collar to yield less mass for race competition, as illustrated in FIG. 10H, in which material has been removed from collars 528,529 relative to collars 520,521 shown in FIG. 10B.
Having thus described a preferred embodiment of the invention in sufficient detail to enable those skilled in the art to make and use the invention, it will be appreciated that numerous variations of the illustrated embodiment may be made without departing from the scope of the invention, such as use of different types of screws or fasteners, different arm plate configurations, different clamp configurations for the stem mount and the handlebar mount, and so forth. It is accordingly intended that the invention not be limited to the embodiment illustrated in the drawings or accompanying description, but rather that it be defined solely in accordance with the appended claims.

Claims

1. A pillar stem structure suitable for removably and adjustably mounting handlebars and aerobars to a bicycle fork or steering column, comprising:

at a first end, a stem-securing structure for securing the pillar stem to a generally vertical fork of a bicycle and, at a second end, an integral support structure;

first threaded openings in the support structure for receiving first fasteners arranged to secure a first sub-assembly to the support structure;

second threaded openings in the support structure for receiving second fasteners arranged to secure a second sub-assembly to the support structure; and

third threaded openings in the support structure for receiving third fasteners arranged to secure handlebar clamps to the support structure.

2. A pillar stem structure as claimed in claim 1, further comprising knee bumpers arranged to fit over and to be secured to said stem securing structure.

3. A pillar stem structure as claimed in claim 2, wherein said knee bumpers include projections arranged to extend into openings in fasteners for the stem securing structure.

4. A pillar stem structure as claimed in claim 2, wherein said knee bumpers are made of a thermal plastic elastomer.

5. A pillar stem structure as claimed in claim 4, wherein said bumpers are arranged to snap onto the stem securing structure.

6. A pillar stem structure as claimed in claim 1, wherein at least one of said first fasteners, second fasteners, and said third fasteners are titanium bolts treated with a physical vapor deposition (PVD) coating.

7. A pillar stem structure as claimed in claim 6, wherein said PVD coating is a color spectrum coated finish.

8. A pillar stem structure as claimed in claim 1, wherein said second threaded openings are situated in a top surface of said pillar stem structure, and further comprising a moisture outlet in communication with a respective said first threaded opening for draining moisture from said first threaded opening.

9. A pillar stem structure as claimed in claim 1, wherein said first threaded openings are situated in a bottom of said pillar stem structure, and further comprising a gasket arranged to seal said second threaded openings when not being used to secure the second sub-assembly.

10. A pillar stem structure as claimed in claim 9, wherein said gasket include projections arranged to fit into and secure said gasket to said second threaded openings.

11. A pillar stem structure as claimed in claim 9, wherein said gasket is made from a thermal plastic elastomer.

12. A pillar stem structure as claimed in claim 1, further comprising at least one eccentric collar member arranged to fit over the fork or steering column and to provide a variably angled surface to which the stem securing structure is clamped in order to vary an angle of the pillar stem relative to the fork or steering column.

13. A pillar stem structure as claimed in claim 12, wherein said collar includes a rim and a cylindrical body extending at a predetermined angle relative to the rim, whereby rotation of the collar relative to a vertical axis changes an orientation of the cylindrical body relative to the vertical axis.

14. A pillar stem structure as claimed in claim 12, wherein said collar includes a gap that enables it to be fitted over the fork or steering column and that serves as a marker for orienting the collar.

15. A pillar stem structure as claimed in claim 12, wherein said collar includes an upper member and a lower member.

16. A pillar stem structure as claimed in claim 12, wherein said collar is a one-piece collar.

17. A pillar stem structure as claimed in claim 12, wherein said first sub-assembly is an aerobar bracket sub-assembly including a bracket, aerobars and aerobars adjustably secured in the bracket.

18. A pillar stem structure as claimed in claim 1, wherein said second sub-assembly is an arm rest sub-assembly including an arm rest support removably secured to the support structure of the pillar stem, arm rest plates, and arm rest plate fasteners for adjustably securing the arm rest plates to the support.

19. An eccentric collar member arranged to fit over a fork or steering column and to provide a variably angled surface to which a stem securing structure is clamped in order to vary an angle of a pillar stem relative to the fork or steering column.

20. A pillar stem structure as claimed in claim 19, wherein said collar includes a rim and a cylindrical body extending at a predetermined angle relative to the rim, whereby rotation of the collar relative to a vertical axis changes an orientation of the cylindrical body relative to the vertical axis.

21. A pillar stem structure as claimed in claim 19, wherein said collar includes a gap that enables it to be fitted over the fork or steering column and that serves as a marker for orienting the collar.

22. A pillar stem structure as claimed in claim 19, wherein said collar includes an upper member and a lower member.

23. A pillar stem structure as claimed in claim 19, wherein said collar is a one-piece collar.