Motorcycle handlebar with shock absorber
Motorcycle handlebar with shock absorber
US Patènt # 6860500
| Invèntors: | Hissam; Dan (Sun City, CA) |
| Assignee: | FASST Company (Long Beach, CA) |
| Appl. No.: | 319408 |
| Filed: | December 12, 2002 |
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMÈNTS
The present invèntion finds utility with a number of vehicles, including, without limitation, motorcycles, all-terrain vehicles (atv's), personal watercraft, snowmobiles and other types of vehicles in which handlebar assemblies are commonly employed to assist in steering of the vehicle. The illustrated embodimènt of the handlebar assembly, however, is particularly well-suited for use with an off-road motorcycle. The description of a preferred handlebar assembly 28 in the context of an off-road motorcycle, therefore, is merely exemplary and is not intended as a limitation of the present invèntion, unless expressly so claimed.
With reference to FÌG. 1, an off-road motorcycle, generally referred to by the reference numeral 10, is shown and includes a body portion 12 and front and rear wheels 14, 16. The front and rear wheels 14, 16 are supported relative to the body portion 12 by front and rear suspension assemblies 18, 20. The front and rear suspension assemblies 18, 20 are configured to support and control movement of the front and rear wheels 14, 16, respectively, throughout a suspension travel path.
Desirably, the front suspension assembly 18 comprises a telescopic front fork assembly having a pair of telescopically engaged fork legs 22 extending along each side of the front wheel 14. The fork legs 22 are connected to the body portion 12 of the motorcycle 10 by upper and lower fork clamps 24, 26. Thus, the front wheel 14 moves along a substantially linear suspension travel path generally parallel to the fork legs 22. Movement of the front wheel 14 occurs against resistance offered by a shock absorber arrangement incorporated within the fork legs 22, as is known in the art. Desirably, a handlebar assembly 28 is connected to the front suspension assembly 18 to permit rotation of the front suspension assembly 18 and front wheel 14 about a steering axis. The handlebar assembly 28 is described in greater detail below.
Preferably, the rear suspension assembly 20 comprises a swingarm 30 pivotally connected to the body portion 12 of the motorcycle 10 and supporting the rear wheel 16 near its rearward end. The swingarm 30 may extend along one, or both, sides of the rear wheel 16. A shock absorber 32 is positioned between the swingarm 30 and the body portion 12 of the motorcycle 10 to provide a force tending to resist rotation of the swingarm 30 and, thus, movement of the rear wheel 16 throughout an arcuate suspension travel path, as is known in the art.
The body portion 12 of the motorcycle 10 desirably comprises an engine 40 supported within a frame 42, the latter commonly being constructed from a plurality of metal tubes welded together. The frame 42 also supports a fuel tank 44 and an elongated, straddle-type seat assembly 46 on which a rider of the motorcycle 10 may sit. A pair of foot pegs 48 (only one shown) are connected to each side of a lower portion of the frame 42 and are configured to provide support for the feet of a rider of the motorcycle 10. Front and rear fenders 50, 52 are supported above the front and rear wheels 14, 16 and are configured to deflect dirt, mud or other debris that might be projected upward by the wheels 14, 16.
The rear wheel 16 is drivingly connected to the engine 40 by a chain and sprocket drive assembly 54. However, other suitable drive arrangements may also be used, such as a belt drive or shaft drive arrangement, for example. The motorcycle 10 has been described in general detail to assist the reader's understanding of the illustrated handlebar assembly 28. Other components of the motorcycle 10 may be considered as conventional and, therefore, additional details are not considered necessary for one of ordinary skill to practice the present invèntion.
With reference to FÌG. 2, the handlebar assembly 28 is illustrated removed from the motorcycle 10, for the purpose of clarity. Generally, the handlebar 28 includes a mounting portion 60 with a right handgrip portion 62 and a left handgrip portion 64 extending to right and left sides, respectively, of the mounting portion 60, when viewed from the perspective of a person sitting on the motorcycle 10. Right and left pivot assemblies 66, 68, respectively, support the right and left handgrip portions 62, 64 relative to the mounting portion 60 and, preferably, are configured to constrain movement of the right and left handgrip portions 62, 64 to substantially vertical, arcuate movement from a normal, or relaxed, position to a compressed position. In addition, the pivot assemblies 66, 68 preferably are also configured to provide a force tending to resist downward movement of the handgrip portions 62, 64. Accordingly, the handlebar assembly 28 is configured to provide shock absorption in addition to the shock absorption provided by the front and rear suspension assemblies 18, 20.
In the illustrated embodimènt, a mounting portion 60 of the handlebar assembly 28 comprises a tubular member, or clamp tube, which is configured to be secured to the upper fork clamp 24 (FÌG. 1) by a standard handlebar clamp arrangement (not shown). A standard handlebar clamp arrangement typically includes a pair of clamp members fixed to the upper fork clamp 24 and spaced on opposing sides of the steering axis of the motorcycle 10. Each clamp member usually includes an upper and lower portion, which cooperate to define a cavity for receiving the clamp tube 60. Fasteners, such as bolts, typically connect the upper and lower portions and permit a clamping force to be applied to the clamp tube 60. In some arrangements, the upper and/or lower portions may be interconnected, to provide additional rigidity to the clamp arrangement. Even with such an arrangement, however, the clamp tube 60 is still primarily clamped only at a pair of spaced locations along the clamp tube 60.
When a standard clamp arrangement, as described immediately above, is used, the mounting portion 60, or clamp tube, is received by the clamp arrangement at a pair of spaced apart locations 70, 72 on the outer surface of the clamp tube 60. Such an arrangement provides beneficial leverage and inhibits deflection of the handlebar assembly 28 when a large force is required to turn the front wheel 14, such as when cornering at high speeds. The outer surface of the spaced locations 70, 72 may be knurled to improve the grip of the clamp arrangement on the clamp tube 60. Preferably, the locations are at least two and one-half inches apart and, more preferably, about four inches apart.
Desirably, the right and left handgrip portions 62, 64 are constructed of tubular members and are supported at a height relatively higher than the clamp tube 60. The difference in height between the clamp tube 60 and the outer ends of the handgrip portions 62, 64 (i.e., where they are normally grasped by a rider of the motorcycle 10) is referred to as the "rise" of the handlebar assembly 28. The rise permits the handgrip portions 62, 64 to be at a comfortable height relative to the clamp tube 60, the height of which is determined primarily by the position of the upper end of the front fork legs 22. In addition, the handgrip portions 62, 64 may extend outward at a rearward angle relative to the clamp tube 60, which is referred to as the "sweep" of the handlebar assembly 28. The rise and sweep of the handlebar assembly 28 may be altered to suit different size or type of vehicles, different riding conditions or individual rider preferences.
As described above, the pivot assemblies 66, 68 support the handgrip portions 62, 64 relative to the clamp portion 60 and, desirably, also constrain the movement of the handgrip portions 62, 64 to substantially vertical, arcuate movement. Preferably, each pivot assembly 66, 68 incorporates a shock absorbing arrangement to provide a force tending to resist downward movement of the handgrip portions 62, 64. In FÌG. 2, the right pivot assembly 66 is illustrated in an exploded condition, for the purpose of clarity.
With additional reference to FÌG. 3, the left pivot assembly 68 is illustrated in section. Although not specifically shown, preferably the right pivot assembly 66 is constructed substantially the same as the left pivot assembly 68. Desirably each pivot assembly, 66, 68 includes a support 74 fixed to the respective end of the clamp tube 60. The support 74 may be connected to the clamp tube 60 by any suitable arrangement, such as interlocking threads, a press-fit arrangement, or welding, for example. Desirably, the support 74 extends upward and terminates in front and rear protruding portions 76, 78, which define a space, or channel, therebetween. In the illustrated arrangement, each of the protruding portions 76, 78 includes an aperture 80 arranged such that an opening of each aperture 80 faces the channel defined by the protruding portions 76, 78. The apertures 80 are aligned with one another for receiving opposing ends of a support shaft 82.
Desirably, each pivot assembly 66, 68 includes a pivot body 84, which supports the respective handgrip portion 62, 64. The handgrip portions 62, 64 may be secured to the respective pivot body 84 by any suitable arrangement, including interlocking threads, a press-fit arrangement, or welding, for example. A portion of the pivot body 84 is sized and shaped to fit within the channel defined by the support 74 and includes an aperture 86 which permits the pivot body 84 to be rotatably supported by the support shaft 82. Accordingly, the pivot body 66 supports the respective handgrip portion 62, 64 for arcuate motion about a pivot axis P defined by the shaft 82. Preferably, the pivot axis P is oriented substantially perpendicular to the axis of the clamp tube 60, referred to herein as the "handlebar axis" and designated by the reference character "H". Although not specifically illustrated herein, the support shaft 82 may include one or more grooves configured to receive a seal member, such as an O-ring, to inhibit dirt or other foreign materials from entering between the shaft 82 and the pivot body 84 or support 74.
As described above, such an arrangement inhibits forward or rearward movement of the handgrip portions 62, 64. In contrast to one-piece handlebars described above, such an arrangement advantageously provides a solid feel to the handlebar assembly 28 when the rider is pulling in a rearward direction, such as during acceleration of the motorcycle 10, without compromising the amount of shock absorbing (i.e., substantially downward) movement that is provided.
In addition, the illustrated arrangement allows shock absorbing movement of the handgrip portions 62, 64, without significantly altering the angular position of the rider's wrists throughout the range of motion of the handgrip portions 62, 64. In contrast, shock absorbing motion of the handgrip portions occurring about an axis parallel to the axis of the handlebar would also cause rotation of the rider's wrists. On most motorcycles and atv's the throttle is controlled by rotation of a handgrip assembly. Accordingly, with such an arrangement, rotation of the rider's wrist due to shock absorbing movement of such a handlebar assembly would also cause unintended and undesirable changes in throttle position.
Preferably, a brace, or crossbar 88, extends from an upper end of the left support 74 to an upper end of the right support 74 to add rigidity to the handlebar assembly 28. The crossbar 88 may be of any suitable shape, however, desirably the crossbar 88 is substantially rectangular in cross-section. In a preferred arrangement, forward ends of each pivot support shaft 82 are exposed from the supports 74 and include an annular groove 87. The crossbar 88 includes an aperture at each end, which accommodate the exposed ends of the shaft 82. Thus, the crossbar 88 is supported on the exposed ends of the shafts 82 and an clip member, or C-clip 89, is positioned within the annular groove 87 of the shaft 82 to secure the crossbar 88 in place. Alternatively, threaded fasteners may be used to secure the crossbar 88 to the pivot assemblies. Further, the crossbar 88 may assume other shapes and/or may be connected to the handlebar assembly 28 by other suitable methods.
With the preferred arrangement, the crossbar 88 interconnects the right and left supports 74 and is spaced from the clamp tube 60 (and handlebar axis H) in the vertical direction. Desirably, the crossbar 88 is substantially at the same height, relative to the clamp tube 60, as the pivot axes P. Advantageously, with such an arrangement, the crossbar 88 substantially prevents outward flexing of the supports 74, due either to deflection of the support 74 or the clamp tube 60, in response to a downward force being applied to the handgrip portions 62, 64. Accordingly, movement of the handgrip portions 62, 64 may be primarily controlled by the shock absorbing arrangements described below, rather than by undesired flexing of the clamp tube 60 or supports 74.
As mentioned above, preferably a shock absorbing arrangement is associated with each handgrip portion 62, 64 to provide a force tending to resist downward movement of the handgrip portions 62, 64. With additional reference to FÌG. 4, the shock absorbing arrangement is described in greater detail. Desirably, each pivot body 84 includes a flange portion 90 extending in a downward direction from an intermediate portion of the pivot body 84 generally perpendicular to both the clamp tube 60 and the handgrip portions 62, 64. An elongated aperture 92 extends through the flange in a horizontal direction and is generally aligned with the handlebar axis H.
The support 74 includes an aperture 94 for supporting a shaft 96, which extends generally horizontally in a lateral direction from the support 74. Desirably, the shaft 96 is positioned below the pivot axis P and passes through the elongated aperture 92 of the flange 90. The elongated shape of the aperture 92 accommodates arcuate movement of the pivot body 84 and handgrip portions 62, 64 relative to the shaft 96, which remains stationary.
A shock absorbing member 100 is positioned between and contacts an inner surface 102 of the flange 90 and an outer surface 104 of the support 74 when the handgrip portions 62, 64 are in a relaxed position. Thus, the shock absorbing member 100 tends to bias the pivot body 84, and the respective handgrip portion 62, 64, rotationally upward relative to the support 74 (and clamp tube 60) and supplies a force tending to resist rotationally downward movement of the handgrip portions 62, 64. Preferably, the shaft 96 is spaced between about one and four inches from the handlebar axis H and, more preferably, between about two inches and two and three-quarters inches from the handlebar axis H. Such an arrangement keeps the shaft 96 sufficiently close to the handlebar axis H to inhibit damage, while also permitting a force applied to the handgrip portion 62, 64 to apply an appropriate force, through the flanges 90, to the shock absorbing members 100.
The shock absorbing member 100 desirably comprises a material that provides a resistive force in response to compression, such as an elastomeric material, for example. Preferably, the shock absorbing member 100 is annular in plan view and substantially rectangular in cross sectional shape. The member 100 desirably is positioned such that one end is adjacent the inner surface 102 of the flange 90 and the opposite end is adjacent the outer surface 104 of the support 74. Preferably, the shock absorbing member 100 includes a central aperture 106 that permits the member 100 to be supported on the outwardly extending shaft 96.
Although the illustrated embodimènt includes a shock absorbing member 100 for each pivot assembly 66, 68, other arrangements wherein a single shock absorbing member, are utilized to provide a biasing force for both pivot assemblies 66, 68 and thus both handgrip portions 62, 64. In addition, other type of shock absorbing arrangements may also be used. For example, a hydraulic shock absorber assembly may be used in place of the elastomeric member 100.
Desirably, each pivot assembly 66, 68 includes a stop arrangement to limit rotationally upward movement of the handgrip portions 62, 64. In the illustrated embodimènt, an outer end of the shaft 96 includes external threads 110 that mate with internal threads 112 of a nut 114. The nut 114 supports a washer 116 in a fixed position along the length of the shaft 96. With reference to FÌG. 4, portions of an inner surface 118 of each washer contacts a portion of the outer surface 120 of the flange 90 on each side of the aperture 92 to limit upward rotation of the pivot body 84. Thus, upward rotation of the respective handgrip portion, 62, 64 is also limited. Accordingly, the stop arrangement defines the normal, or relaxed, position of the handgrip portions 62, 64 relative to the clamp tube 60. Furthermore, the stop arrangement may limit, or prevent, upward movement of the handgrip portions 62, 64 beyond the normal position. Accordingly, the rider is provided with a solid feel to the handlebar 28 when pulling in and upward direction.
With reference to FÌG. 5, the left handgrip portion 64 is shown in both a relaxed position (solid lines) wherein the shock absorbing member 100 is biasing the flange 90 into contact with the washer 116 and a compressed position (phantom lines) wherein the handgrip portion 64 has moved rotationally downward to absorb impact forces resulting from the motorcycle 10 traversing rough terrain or landing from a jump. As described above, preferably the handgrip portion 64 moves from the relaxed position to the compressed position through an arcuate path about the pivot axis P. Such movement absorbs forces and vibrations that would otherwise be transmitted to a rider of the motorcycle 10.
Shock absorption is provided by the shock absorbing member 100 being compressed between the pivot body 84 and the support 74, which reduces the shock to the hands and arms of the rider that would otherwise result from forces that are not absorbed by the suspension assemblies 18, 20 of the motorcycle 10. Advantageously, the amount of movement of the ends of the handgrip portion 64 (i.e., where the rider would normally grip the handlebar 28) is greater than the amount possible with the bending, cantilever movement of a conventional, one-piece handlebar. Desirably, the ends of the handgrip portion 64 moves a travel distance D, measured as a linear distance in a substantially vertical direction, of at least one-half inch and, preferably, at least about one inch, in order to provide an advantageous degree of shock absorption. Conversely, if the travel distance D is too large, movement of the handgrip portion 64 while riding may feel unnatural to the rider. Accordingly, it is preferred that the travel distance D is less than about two inches. The range of travel distances D provided above is presently preferred for a typical off-road motorcycle application. However, other travel distances D are possible, and may be preferred in other applications.
The pivot axis P is generally aligned in the lateral direction with the ends of the clamp tube 60 in the illustrated embodimènt. Desirably, with such an arrangement, the pivot axis P of the right pivot assembly 66 and the pivot axis P of the left pivot assembly 68 are spaced between about six and twelve inches apart. Preferably, the pivot axes P are spaced about seven and one-half to ten inches apart and, more preferably, about nine and three-sixteenths inches apart. The provision of two separate pivot locations being spaced from one another, as described above, provides a desirable diameter to the arc of rotation for the handgrip portions 62, 64. Conversely, when a single pivot is used, or when the pivots are too close together, the handgrip portions 62, 64 move through an arc of a larger diameter. This results in movement of the handgrip portions that is more noticeable to the rider and, if large enough, may result in the rider's wrist assuming an unnatural position.
Although the above-described arrangement is preferred, other positions of the pivot axis P, with respect to one another and/or the handlebar axis H, may also be utilized. In addition, as will be appreciated by one of skill in the art, the handgrip portion 64 may be configured to move to a lesser, or greater, degree than illustrated in FÌG. 5, depending on the type of shock absorbing member 100 selected, the relative distance between the member 100 and the pivot axis P, or alternative configurations of the pivot assembly 66. Although not separately illustrated, desirably, the right pivot assembly 66 is constructed substantially the same as the left pivot assembly 68.
Advantageously, the illustrated arrangement permits adjustment of a height of the handgrip portions 62, 64 relative to the clamp portion 60, when in a relaxed position of the handlebar assembly 28. Such a feature permits adjustment of the handlebar assembly 28 to suit riders of differing size, individual rider preference, or specific riding conditions. Desirably, height adjustment is achieved by movement of the nut 114 relative to the shaft 96.
For example, movement of the nut 114 outwardly with respect to the shaft 96 permits the pivot body 84 (and handgrip portion 62, 64) to rotate farther upward before contacting the washer 116. Conversely, inward movement of the nut 114 relative to the shaft 96 causes the outer surface 120 of the flange 90 to contact the washer 116 in a rotationally lower position and, therefore, lowers the relaxed height of the handgrip portion 62, 64 relative to the clamp portion 60. Adjustment of the relaxed height of the handgrip portions 62, 64 is illustrated in phantom in FÌG. 6. As described above, the shock absorbing members 100 operate to bias the handgrip portions 62, 64 into their uppermost, relaxed positions, absent a downward force due to the motorcycle 10 traversing rough terrain or landing from a jump, for example.
Advantageously, the nut 114, which operates as the adjustment mechanism for the height adjustment of the handgrip portions 62, 64 in the illustrated embodimènt, is easily accessible. Preferably, the engagement surface (peripheral surface) of the nut 114 is exposed such that the axial position of the nut 114 may be easily adjusted without disassembly of the handlebar assembly 28. Such an arrangement allows adjustment to the height of the handgrip portions 62, 64 to be accomplished quickly and easily. In an alternative arrangement, the nut 114 may be modified, or replaced by another mechanism, to provide an engagement surface that permits adjustments to be made by hand, without the use of tools.
The above-described embodimènt of the handlebar assembly 28 is preferred due to a number of advantages. For example, the illustrated arrangement is relatively lightweight and is capable of being manufactured at a reasonable cost. Furthermore, the pivot assemblies 66, 68 are arranged to minimize the possibility of damage during a crash. Advantageously, the shock absorbing arrangement (flange 90, shaft 96, nut 114, washer 118 and shock absorbing member 100) is positioned between the respective handgrip portion 62, 64 and the clamp tube 60 in the vertical direction. Such an arrangement positions the shock absorbing arrangement so that it is protected from damage by the pivot body 84 and support 74. In addition, the positioning of the shock absorbing arrangement provides a clean, unobtrusive appearance to the handlebar assembly 28. Furthermore, the provision of two separate pivot assemblies 66, 68 permits each handgrip portion 62, 64 to be easily replaced if damaged during a crash.
Although the illustrated embodimènt is preferred for at least the reasons presented above, nonetheless, other variations are also possible. For example, providing a clamp tube 60 as described herein permits the handlebar assembly 28 to replace conventional handlebars using standard mounting arrangements. However, other methods of connecting the present handlebar assembly 28 to the motorcycle 10 may also be used, such as integrating the pivot assemblies 66, 68 with the upper fork clamp 24, for example. Furthermore, other arrangements to permit shock absorbing motion of the handgrip portions 62, 64 are also possible. For example, the pivot assemblies 66, 68 may be positioned in other locations or may share one or more individual components, as will be appreciated by one of skill in the art.
Although the present invèntion has been described in the context of a preferred embodimènt, it is not intended to limit the invèntion to the provided example. Modifications to the above-described handlebar assembly apparent to one of skill in the art are considered to be part of the present invèntion. Accordingly, the invèntion should be defined solely by the appended claims.
