Land vehicles: wheels and axles – Wheel – Tension wheel; e.g. – spoke
Reexamination Certificate
2001-11-08
2004-01-20
Morano, S. Joseph (Department: 3617)
Land vehicles: wheels and axles
Wheel
Tension wheel; e.g., spoke
C301S058000, C301S059000
Reexamination Certificate
active
06679561
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to paired spoke bicycle wheels having an optimized rim extrusion and spoke pacing which enables lighter and stronger wheels for improved performance. By spacing tensioned spokes optimally, mechanical stress on the rim structure is minimized between rim failure from high stress concentration and rim distortion from longer distances between spokes. This enables lighter and stronger rims, the rims being optimized having a sectional shape of an irregular pentagon.
2. Description of Related Art
Several pieces of prior art describe the potential, and as yet, not optimized advantages of paired spoke bicycle wheels over a century of development. As early as 1889, the U.K. patent to Lovelace No. 3056 (Feb. 20, 1889) describes paired spokes: “the spokes the each are screwed into the hub flange is w, in a line which is a tangent to a circle somewhat smaller than the said flange, and two spokes, that is to say, one from each end of the hub, meet at the same point in the rim as shown clearly in
FIG. 5 .
. . ”. The motivation for paired spokes is explained, continuing: “thus bringing the strain to bear equally upon the rim and avoiding the liability to buckle, which is attendant on the usual arrangement”.
Another paired spoke reference is French patent No. 1,019,285 issued to Menet dated Jan. 20, 1953. A copy of an English translation of Menet was filed in the application which issued as U.S. Pat. No. 5,931,544. It is on this translation that the explanation herein relies, although the terminology is also recognized as consistent with the disclosure in Menet's drawings.
Menet describes a bicycle wheel having, among other features, “ . . . on the rim on both sides of the median plane, perpendicular to the axis of the wheel, and arranged more or less in a straight line parallel to the axis of said wheel . . . ”. Menet teaches a hub, axle and paired spokes: “the spokes are distributed on the rim in groups of two, having their . . . points of attachment on the hub of the wheel almost on the same line . . . ”. Menet describes tensioned, paired spokes, with two ends: “ . . . on the threaded ends of the spokes, nuts
4
are screwed on in the usual manner . . . . On the other end the two spokes of the same group will advantageously be fastened to the hub of the wheel, at points 5 . . . ”.
While Lovelace described the advantage as reduced “strain”, Menet's translation uses a more dynamic description of the purpose of paired spoking: “thus increasing the lateral rigidity of the wheel and freeing the rim from the abnormal torsional forces to which normal rims are subjected when used until it becomes possible to considerably ease the strain on the rims without risk of warping” and “to attain as perfect a symmetry as possible of the spokes on [on] both sides of a median plane, perpendicular to the axis of the wheel”.
Bicycle wheels are, of course subject to both static loads and dynamic forces, and the “strain” observed by Lovelace necessarily translates to transverse changes at the rim as a tensioned spoke wheel, bearing the mass of the bicycle and rider, and acceleration and deceleration forces, contacts pavement while rolling. These dynamic forces are Menet's “torsional forces to which . . . rims are subjected when used”. Measurements of this are suggested in the aforementioned U.S. Pat. No. 5,931,544, although the inventor herein has been unable to reproduce all of the tests described in U.S. Pat. No. 5,931,544, or its parent, U.S. Pat. No. 5,104,199. However, it is believed that the tests in these two patents were static lateral load tests, not dynamic tests. It is believed that the lack of precision resulted in rims that were unduly heavy for their strength because of their closely spaced spoked design.
Two other problems were observed in the prior art. These are not believed to have been solved by the prior art.
First, paired spokes, while producing a more even strain having advantages on a rotating wheel, have the considerable disadvantage of concentrating that strain in a small area on the rim. Menet suggests a reinforcing boss: “To reinforce the fastening of the spokes, 4 two-holed bracket
7
can be inserted between the nuts and the rim”. It will be appreciated that adding material and pieces to a structure optimized for strength and weight is disadvantageous, in addition to the added expense and other inefficiency of having added components needed.
Second is the difficulty in placing paired spokes that are perfectly paired precisely opposite one another on a narrow rim. A second Lovelace patent, No. 5968 Apr. 19, 1890 anticipated one of the embodiments of Dietrich '544: “The arrangement of spokes shown in
FIGS. 4 and 5
, of my aforesaid drawings cannot conveniently be applied to a narrower rim, as there is not room for the spokes to be placed opposite each other; in such cases I make two holes, one in front of the other, and near together for each pair of spokes going to opposite sides of the hub, this gives practically all the advantages of the former arrangement, while it enables the method to be applied to narrow rims.” The “aforesaid drawings” are those in Lovelace No. 3056. The circumferential offset is shown in
FIGS. 6 and 7
of the Lovelace 5968 patent and described: “In the improved arrangement for attaching spokes to the wheel rims, I make two holes in the rim one in front of the other and near together, but slightly on the skew, that is to say the holes are made in a line which is diagonal to the rim, the holes are countersunk on the inside to receive the heads of the spokes and one spoke of each pair goes to one end of the hub and the other spoke to the other end, as described in my prior specification No. 3056 of 1899.” Lovelace 5968 if scaled to the proportion of modem road bicycle wheels, of about one inch, would provide circumferential spacing of about 0.3 inches.
U.S. Pat. No. 1,474,631 issued Nov. 20, 1923 to House also shows a combination of paired (
13
,
15
) and unpaired (
14
) spokes on a wheel. House explains that the heavy loads on wagons or artillery carriages subject spoked wheels to forces that impose lateral or transverse loads as the wheels rotate.
Certain production paired spoke rims made by the assignee of this application, and which are outside the scope of the teachings of the aforementioned Dietrich '544 patent have had spokes spaced about 28 mm (1.1 inches) to about 33 mm (1.3 inches). While functional, these wheels need to rely on the rim rigidity to reduce the tendency towards wheel wobble, as opposed to the invention which optimizes for reducing both stress and wobble tendency. Embodiments of Dietrich-style paired spoke wheels have typically been limited to not greater than three quarters of 1 inch (19.05 mm) while standard, non-paired spoke wheels typically have spacing of around 2 inches.
Other commercial paired spoke embodiments have been sold, but these mount spokes in a reversed manner such that the spoke head is in the side wall rim and the nipple is at the hub. These are typified in U.S. Pat. Nos. 6,196,638, 6,213,562 and 6,234,580, or with crossed wire spokes penetrating the side wall of the rim, U.S. Pat. Nos. 6,158,819 and 6,231,128. These provide a much different solution than that of the instant invention, putting more material to support the rim, at the expense of a deeper, hence heavier, structure, and using a complex hub.
The spoking of the invention solves the two problems of varying transverse loads upon rotation under axle loads, while also avoiding concentration of stress and strain on the structure of the rim by pairing spokes but spacing them sufficiently apart to decrease the loads on the rim structure to levels which permit thinner, lighter rims.
Rim sections also have need for optimized form, particularly for rear wheels used on bicycles having modem multiple speed cog sets. While symmetrically formed and symmetrically spoked rear wheels have been adequate for geared bicycles typically having five rear cogs—when mult
Addink Bradley J.
Rettig Dirk J.
Barness Thornburg
Bellinger Jason R.
Brezina David C.
Morano S. Joseph
Trek Bicycle Corporation
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