Patent Application
20120017440
There is described a method of a motorcycle frame during conversion to a motorized tricycle.
It has become popular to convert a motorcycle into a motorized tricycle. For these conversions, a tricycle conversion kit is attached to a pre-existing motorcycle frame of the motorcycle being converted. Some types of pre-existing motorcycle frames are generally of an inverted L-shape. Problems have been experienced of structural damage in the form of stress fractures to the pre-existing inverted L-shape motorcycle frame after tricycle conversion due to increased dynamic loading. What is required is a method of converting a motorcycle into a motorized tricycle without structural damage to the pre-existing motorcycle frame due to increased dynamic loading.
There is provided a method of reinforcing an L-shaped motorcycle frame during conversion to a motorized tricycle. The L-shaped motorcycle frame is an inverted L-shape with a horizontal portion and a vertical portion. A tricycle frame is provided having spaced apart side plates with a forwardly and downwardly extending portion which terminates in a mounting attachment. The side plates are fastened to opposed sides of the horizontal portion of the L-shaped motorcycle frame. The mounting attachment is secured to the vertical portion of the L-shaped motorcycle frame. This forms a triangular truss with the forwardly and downwardly extending portion of the side plates of the tricycle frame angled between the horizontal portion and the vertical portion to provide rigid support to the L-shaped motorcycle frame.
The triangular truss formed by the combined structure of the L-shaped motorcycle frame and the tricycle frame, prevents bending stresses at potential fracture points on the L-shaped motorcycle frame.
As will be hereinafter illustrated and described the triangular truss forms a right angle triangle, with the forwardly and downwardly extending portion of the side plates of the tricycle frame providing a hypotenuse. It will be appreciated that the triangular truss need not form a right angle triangle to provide rigid support.
As will hereinafter illustrated and described, the tricycle frame forms a motorcycle frame support that supports the L-shaped motorcycle frame from below and laterally confines the motorcycle frame. This is accomplished by spacing the side plates so that they are closely positioned on opposed sides of the motorcycle frame and having a difference in spacing between the side plates and the struts. The difference in spacing forms a shoulder that supports the motorcycle frame from below.
Another problem encountered when converting a motorcycle to a motorized tricycle is twisting loads caused when the motorized tricycle operates with two rear wheels. This twisting load can cause bending of the pivot pin used to attach a tricycle swing arm to the motorized tricycle and it can damage the pivot mount. Even more beneficial result may be obtained when an auxiliary pivot support is provided having an interior surface defining a bushing. The auxiliary pivot support is secured to the mounting attachment to provide additional support to the pivot pin and pivot mount for the tricycle swing arm.
Yet another problem encountered when converting a motorcycle to a motorized tricycle is dynamic stresses. Even more beneficial results may be obtained when an auxiliary shock absorber is secured between an upper shock mount on the tricycle frame and a lower shock mount on a tricycle swing arm. The auxiliary shock absorber is centrally positioned between the side plates of the tricycle frame and centrally positioned between two rearwardly extending portions of the tricycle swing arm. With this auxiliary shock absorber, additional suspension loading caused by the motorized tricycle conversion is directed through the tricycle frame. This isolates the motorcycle rear frame from most of the additional dynamic stresses created by the motorized tricycle conversion.
These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein:
A motorcycle frame generally identified by reference numeral 10, will now be described with reference to
Structure and Relationship of Parts:
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Operation:
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In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.
The following claims are to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, and what can be obviously substituted. Those skilled in the art will appreciate that various adaptations and modifications of the described embodiments can be configured without departing from the scope of the claims. The illustrated embodiments have been set forth only as examples and should not be taken as limiting the invention. It is to be understood that, within the scope of the following claims, the invention may be practiced other than as specifically illustrated and described.
