Most motorcycles are equipped with a kickstand mounted on one side of the frame of the motorcycle that allows the motorcycle to be left in a standing position when the motorcycle is parked by the rider. Such a motorcycle kickstand, also referred to as a "side stand," supports the motorcycle in a slightly leaning position. Many such motorcycle kickstands include a spring having one of its ends attached to the frame of the motorcycle and its other end attached to the pivotal arm of the kickstand. The spring is attached so as to urge the pivotal arm towards one of two positions, either a fully-extended position in which the pivotal arm is capable of supporting the weight of the motorcycle or a fully-retracted position in which the pivotal arm rests during operation of the motorcycle.

Prior to riding the motorcycle, the rider must first raise the parked motorcycle from its tilted position to an upright position, then manually move the kickstand, usually with his or her foot, allowing the kickstand to travel to its fully-retracted position. However, on many motorcycles, there is nothing to prevent the rider from riding the motorcycle without having first retracted the kickstand. In such cases, the extended kickstand does not interfere with the operation of the motorcycle when the rider is riding straight ahead and the motorcycle is in a perfectly vertical, or upright, position. However, when the rider leans the motorcycle in the process of turning, the extended kickstand may make contact with the ground, depending upon the amount of lean that the turn requires. Of course, since kickstands are almost universally attached on the left-hand

side of the motorcycle, only left-hand turns will be affected.

The consequences of riding a motorcycle when the kickstand is still in its fully-extended position depend upon factors such as the surface of the road on which the motorcycle is being ridden. On relatively rough roads having a relatively large coefficient of friction, when the extended kickstand makes contact with the surface of the road, the relatively rough road surface will force the kickstand to retract from its fully-extended position. The force imparted to the motorcycle when the kickstand contacts the road can cause difficulties in maintaining the motorcycle in an upright position. Once retracted, there is no detrimental effect on the rider's ability to complete the turn.

Smooth roads having a relatively low coefficient of friction do not generate enough backward force on the kickstand arm to cause it to retract, and as a result, the kickstand can remain extended through the turn. in this case, the extended kickstand acts to limit the amount of bank or lean of the motorcycle and not only hinders completion of the turn, but inhibits sharp turns. In any case, motorcycle riders have sustained injuries when they have neglected to retract the kickstand. Attempts to overcome this problem of inadvertently riding the motorcycle with the kickstand in the extended position have included complicated mechanisms which either prevent motorcycle operation with the kickstand in the extended position or automatically retract the kickstand upon the operation of the motorcycle. These mechanisms generally lack an easy retrofit capability so that they cannot be simply incorporated into existing kickstands.

Summary of the Invention This problem of motorcycle operation with an extended kickstand is simply and easily overcome by this invention which in one aspect provides a motorcycle kickstand with a fixed mounting bracket, a pivotal arm and a spring

connected to both the mounting bracket and the arm which urges the pivotal arm towards its fully-retracted position regardless of the position of the arm. Thus, even when the kickstand is fully-extended, the spring urges the kickstand arm towards its fully-retracted position. As a result, when the rider tilts the motorcycle from its parked leaning position to its upright riding position, the spring causes the pivotal arm to be automatically moved towards its retracted position. Depending on the strength of the spring used and other factors, the kickstand will be automatically moved either to its fully-retracted position or to a position intermediate its fully-extended position and its fully-retracted position. In case the kickstand is partly retracted, it will be pointed in a backwards direction with respect to the motorcycle and will retract further upon any subsequent contact with the road during a turn, regardless of the coefficient of friction.

In another aspect, the kickstand of the invention incorporates a bolt about which the kickstand arm pivots, the bolt having an extension which abuts the spring causing the spring tension to be increased as the arm is moved towards its fully-extended position. The bolt provides a very beneficial retrofit capability so that conventional kickstands can be modified in accordance with the invention.

This invention thus provides a motorcycle kickstand, having a pivoted support arm for attachment to the motorcycle, the arm being pivotable from the fully-extended position to the fully-retracted position. Resilient means urge the pivot arm from the fully-extended position to the fully-retracted position. Force increasing means are provided for increasing the force urging the pivot arm from its fully-extended position to its fully-retracted position when the pivot arm is pivoted past a predetermined position. Advantageously, this predetermined position is a position intermediate the fully-extended position and the fully-retracted position, such that the pivot arm remains

in the intermediate position until urged from that position by an additional force.

These and other objects, features and advantages of this invention will be apparent in view of the following detailed description of a preferred embodiment, which is explained with reference to the figures, a brief description of which is provided below.

Brief Description of the Drawings Fig. 1 is a front view of a motorcycle in its parked position;

Fig. 2 is a perspective view of a kickstand in accordance with the invention attached to the frame of a motorcycle;

Fig. 3A is a perspective view of the kickstand of Fig. 2 in a first, extended position;

Fig. 3B is a perspective view of the kickstand of Fig. 2 in a second, retracted position;

Fig. 4A is an illustration of a portion of the kickstand of Fig. 2 when the kickstand is in its fully- retracted position;

Fig. 4B is an illustration of a portion of the kickstand of Fig. 2 when the kickstand is in a position intermediate its fully-extended position and its fully- retracted position; and Fig. 4C is an illustration of a portion of the kickstand of Fig. 2 when the kickstand is in its fully- extended position.

Detailed Description of a Preferred Embodiment

A motorcycle kickstand 10 in accordance with the invention is illustrated in the figures. The kickstand, also known as a "side stand," is attached to the left side of a motorcycle as shown in Fig. 2. As used herein,

"forward" means towards the front wheel and tire of the motorcycle, and "down" or "lower" are with respect to the ground on which the motorcycle is traveling.

The kickstand 10 has a mounting plate 12 which is attached to the frame 14 of the motorcycle by conventional

means such as welding, or possibly by fasteners such as bolts. The remaining elements of the kickstand 10 are attached to the mounting plate 12.

Referring now to Fig. 3A, these elements include a clevis 16, or U-shaped metal shackle, a pivotal arm 18 rigidly connected to the clevis 16, and a pivot bolt 20 which pivotally connects the clevis 16 to the mounting plate 12. The arm 18 includes a foot 22 at its lower end, a metal eyelet 24 connected to the arm 18 between the foot 22 and the clevis 16. An L-shaped member 25 is connected to the arm 18 adjacent the foot 22, with the short portion of the member 25 projecting outward, away from the motorcycle. A cylindrical spring anchor 28 is connected to the mounting plate 12 above and slightly forward of the pivot bolt 20 (Fig. 4A) . One end of a spring 26 is attached through the hole in the eyelet 24, with the other end of the spring 26 being attached to the anchor 28.

The bottom portion of the mounting plate 12 has an angled stop 30 (Fig. 3B) that abuts against the clevis 16 to limit the clockwise rotation of the kickstand arm 18. The stop 30 limits the motion of the kickstand 18 and ensures that the arm 18 angles slightly forward when the motorcycle is in its parked position.

The counterclockwise rotation of the arm 18 is limited by a stop 32 on the upper portion of the mounting plate 12 or on the frame of the motorcycle. The stop 32 is illustrated as comprising a horizontally oriented offset located above the pivot bolt 20, and below the spring anchor 28. The stop 32 is positioned such that the clevis 16 hits the stop 32 to limit the counterclockwise motion of the kickstand arm 18 as shown in Fig. 3B.

The pivoting of the arm 18 is controlled by the interaction of the spring 26 and a protrusion which may take the form of a cylindrical metal extension 34 of the pivot bolt 20 that is coaxial with the pivot bolt 20. As the arm 18 is pivoted about bolt 20, the distance from the eyelet 24 to the spring anchor 28 changes, and as a result,

the length or displacement of the spring 26 changes. Since the force exerted by a spring is proportional to its displacement, the spring 26 exerts a force on the arm 18 which varies with its displacement. As a result, the spring 26 urges the kickstand arm 18 to the position in which the displacement of the spring is minimized.

Now referring to Fig. 4A, a portion of the kickstand 10 is shown with its arm 18 in the fully-retracted position which, for purposes of this description, means the position that a kickstand normally occupies when the motorcycle to which it is attached is being ridden. In this position, the pivot bolt 20 and its extension 34 are located between the spring anchor 28 and eyelet 24 on the horizontal axis, and slightly below the horizontal level of the eyelet 24. The length through which the spring 10 is stretched when the kickstand is in the retracted position is shown as LR. This length LR is the shortest length through which the spring 26 is stretched in any position of the kickstand. The force exerted by the spring 26 in this fully-retracted position is offset from, or eccentric to, the pivot 20 so as to create a counterclockwise torque about the pivot 20 which urges the kickstand arm 18 to remain in its fully- retracted position.

Fig. 4B illustrates the kickstand arm 18 in a position intermediate its fully-retracted position and its fully- extended position. In Fig. 4B, the spring anchor 28, the pivot bolt 20 and the eyelet 24 are positioned along a straight line, and the spring 26 is stretched along this straight line by an amount Lj. Since the distance between the spring anchor 28 and the eyelet 24 is larger when the arm 18 is in this intermediate position than the corresponding distance when the arm is in its fully- retracted position, Lj is larger than LR, SO that an additional force is exerted by the spring 26. In this intermediate position, however, the force exerted by the spring 26 is along the length of the arm 18 such that no rotational moment is exerted on the kickstand 10 by the

spring 26. Thus, if released in this position, the kickstand 10 would remain in this intermediate position.

Fig. 4C illustrates the kickstand 10 in its fully- extended position which is the position that the arm 18 occupies when it is supporting the motorcycle in a parked, slightly leaning position, as shown in Figs. 1 and 2. When in this position, the foot portion 22 of kickstand arm 18 is angled slightly towards the front of the motorcycle, with the arm 18 being positioned ahead of an imaginary vertical line drawn through the center of the pivot bolt 20, as best seen in Figure 4C.

A stem portion 36 of spring 38 is relatively stiff and inflexible compared to a coiled portion 38 of the spring 26. The stem portion 36 is in contact with the cylindrical extension 34 of the pivot bolt 20, and the spring 26 is thereby prevented from occupying a position along a straight line path from the eyelet 24 to the anchor bolt 28.

The protrusion, or extension 34 acts as a movement limiting element to prevent the intermediate portion of the spring 26 from moving "over-center," or past the pivot bolt

20. The spring 26 is stretched to a length of L*g, which includes a straight-line portion and a curved portion as shown in Fig. 4C. In particular, the uppermost part of the coil portion 38 of the spring 26 is curved, or angularly deflected. Because of this additional curved stretching of the spring 26, L-g is greater than Lj and the tension on the spring 26 is further increased compared with the spring tension in the intermediate position of Fig. 4B. Thus, the cylindrical extension 34 acts as a tension-increasing element which increases the force exerted by the spring 26.

The stem portion 36 of the spring 26 also acts as a leaf spring to exert an additional force on the arm 28.

The contact of the spring stem portion 36 on the extension 34 prevents the spring from going "over-center" and pulling clockwise on the arm 18. Instead, the force in the stretched spring 26 and the force in the spring stem 38 are directed to create a counterclockwise rotational

movement on the arm 18. The extension 34 and spring 26 thus act to provide not only an increase in the spring force, but to exert a counterclockwise torque on the kickstand arm 18. In order to park a motorcycle using the kickstand 10 shown in the drawings, the rider first dismounts and then, while holding the motorcycle vertical, uses his or her foot to overcomes the force of the spring 26 and urge the kickstand arm 18 to its fully-extended position. The foot 22 or the "L" shaped member 25 provide a means for the riders foot to readily engage and rotate the arm 18. The rider then allows the motorcycle to tilt while holding the kickstand arm 18 in the fully-extended position until the foot 22 of the kickstand arm 18 contacts the ground. At this point, the weight of the motorcycle exerts a force on the arm 18 sufficient to prevent the spring 26 from retracting the arm 18 to the fully-retracted position.

Further, since the kickstand arm 18 is angled forward in the fully-extended position (Fig. 4C) , the force exerted by the weight of the motorcycle on kickstand arm 18 urges the arm 18 to rotate clockwise against the stop 30. Thus, the arm 18 is prevented from moving towards its retracting position and the motorcycle will remain in its parked position. When the rider subsequently untilts the motorcycle in preparing to ride it, the weight of the motorcycle will no longer prevent the kickstand arm 18 from moving counterclockwise towards its retracting position, and the arm 18 will automatically begin retracting as soon as the motorcycle is untilted by the rider. If the counterclockwise torque exerted by the spring 26 is sufficient, the arm 18 will retract to the fully-retracted position of Figure 4A.

Advantageously, the force of the spring 26 and the friction in the pivot 20, clevis 16 and mounting plate 12 are such that the position to which the arm 18 automatically retracts is an intermediate position between its fully-extended and fully-retracted positions, for

example, the position shown in Fig. 4B. In this intermediate position, the force generated by the spring passes through the center of the pivot 20 and thus produces no turning moment about the pivot 20. If the rider then forgets to fully retract the aim 18 prior to riding the motorcycle, the arm 18 will be forced upwards towards its fully-retracted position upon any subsequent contact with the road, for example, during a left turn, regardless of the coefficient of friction of the road. This occurs because the kickstand 10, as shown in Fig. 4B, points slightly toward the back of the motorcycle in contrast with a kickstand that has been inadvertently left in its fully- extended position in which it juts forward, as shown in Fig. 2. A rearward or upward force exerted on the kickstand 10 from contact with the road will cause the arm 18 to move so the force exerted by the spring 26 is offset from the pivot 20 in a direction which urges the arm 18 into the fully- retracted position of Fig. 4A.

While in the embodiment just described, the arm automatically retracts to an intermediate, straight line position, the arm could be made to retract to a different position. The extent to which the arm will automatically retract depends upon the strength of the spring 26 which is used, the coefficient of friction between the clevis 16 and the mounting plate 12, and the relative locations of the pivot bolt 20, eyelet 24, and the spring anchor 28. For example, the use of a large spring that generates a lot of force in combination with a very easily pivotable arm 18 would tend to cause the inertia of the pivoting arm to carry the arm past the straight line position shown in Fig. 4B and make the arm 18 completely retract to its fully- retracted position.

During extension of the kickstand 10, a stable position may be created at the centered location of the stand, with the kickstand 10 in a substantially vertical plane, or even at a slightly forward position, by adjusting the diameter at the cylindrical extension 34 in relation to

the position of the anchor bolt 28 and the size of the spring stem 36. This will avoid any problems encountered in the system in which the stand is positively sprung towards the fully-retracted position throughout the entire range of travel of arm 18. With this latter system, however, the rider must maintain foot contact with the kickstand until the motorcycle is in the fully-tilted position, which is sometimes awkward and can result in dropping the motorcycle. Modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only, and is for the purposes of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure may be varied without departing from the spirit of the invention, and the exclusive use of all modifications which come within the scope of the appended claims is reserved.