Automatically adjustable rear suspension for trike

An automatically adjustable rear suspension. A supply of pressurized gas is pneumatically connected to a valve, and at least one air shock is also pneumatically connected to the valve. A pushrod is mechanically connected between a trike frame and a trike swing arm, and actuates the valve in order to maintain the distance between the trike frame and the trike swing arm at a factory pre-set value. Each air spring is disposed between an L arm rigidly attached to the trike swing arm, and the trike frame. In the preferred embodiment, a gas shock absorber was also disposed between the trike frame and the trike swing arm.

FIELD OF THE INVENTION

This invention relates to motorized trikes, and in particular to an automatically adjustable rear suspension for trike.

BACKGROUND OF THE INVENTION

Motorcycles comprise an important part of our transportation system, and have been around for over a century. Gottlieb Daimler, a German engineer, is generally credited with inventing and building the first motorcycle in 1885. He mounted a four-stroke piston engine to a wooden bicycle frame. Following a few decades of development, the motorcycle became a reliable, useful vehicle during the early 1900's.

While today's motorcycles do not differ significantly in appearance from the early models, they do incorporate important improvements. Modern motorcycles have stronger frames, more powerful engines and more dependable brakes. Larger, softer seats make riding more comfortable, and hydraulic springs help lessen road shocks.

During recent decades, as the disposable income and affinity for comfort of motorcycle afficionados have increased, large touring motorcycles have become popular. These motorcycles provide unparalleled stability, comfort and power to their riders.

Still another motorcycle refinement which has gained recent popularity is the three-wheel conversion of large touring motorcycles. This conversion typically involves installing an automotive rear end on an existing motorcycle frame, resulting in one front wheel and two rear drive wheels. This three wheel conversion, also known as a “trike”, affords its riders increased comfort and stability.

One problem associated with modern trikes is keeping the motorcycle frame at the correct angle relative to the surface upon which the trike rests. It is important to maintain the motorcycle frame at the correct angle relative to the surface upon which the trike rests in order to optimize the handling characteristics and ride comfort of the trike. This problem arises especially when drivers of different weights occupy the front seat, or when a passenger climbs into the rear seat. Although front-to-rear leveling arrangements have been taught within the art for conventional two-wheel motorcycles, Applicant is not aware of the existence of any such systems which are usable on trikes. Thus, it would be desirable to provide an automatically adjustable rear suspension for trike which maintains the motorcycle frame at the correct angle relative to the surface upon which the trike rests.

Another problem associated with currently available trikes is a phenomenon known as pushback. Pushback is the reaction of the motorcycle steering wheel to bumps which the rear wheels see. For example, if the left rear wheel hits a bump, then the front wheel will tend to veer right due to pushback. Conversely, if the right rear wheel hits a bump, then the front wheel will tend to veer left. Thus, it would be desirable to provide an automatically adjustable rear suspension for trike which minimizes pushback.

SUMMARY OF THEE INVENTION

Accordingly, it is an object of the present invention to provide a an automatically adjustable rear suspension for trike which maintains the motorcycle frame at the correct angle relative to the surface upon which the trike rests. Design features allowing this object to be accomplished include a compressor pneumatically connected to an accumulator, at least one air spring pneumatically connected to the accumulator through a valve, and a valve pushrod connecting the valve to an axle. Advantages associated with the accomplishment of this object include optimization of the handling characteristics and ride comfort of the trike.

It is another object of the present invention to provide a provide an automatically adjustable rear suspension for trike which minimizes pushback. Design features allowing this object to be accomplished include an air spring mounted between a trike frame and an L arm associated with each rear wheel. Benefits associated with the accomplishment of this object include increased trike controllability and rider comfort.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now toFIG. 1, we observe a side view of motorcycle frame2with trike frame4and trike swing arm6attached, upon which the instant automatically adjustable rear suspension is installed. Trike swing arm6is pivotably attached to motorcycle frame2at pivot point8. Thus, trike swing arm6is free to pivot relative to motorcycle frame2around pivot point8as indicated by arrow10. Axle18is rigidly attached to trike swing arm6.

Referring now also toFIG. 2, a pair of L arms12is rigidly attached to trike swing arm6. Each L arm12comprises an L arm horizontal member14rigidly attached to an L arm vertical member16. An air spring24is sandwiched between each L arm horizontal member14and trike frame4. The extent to which air springs24are inflated determines the angle of motorcycle frame2and trike frame4relative to a surface upon which the motorcycle rests, as indicated by arrow11.

The extent to which air springs24are inflated is determined by valve20. Valve20is a commercially available height air control valve which is normally closed, and which has two open positions: one open position inflates air springs24through air spring supply line26, and the other open position deflates air springs24through air spring supply line26.

Valve24receives its supply of pressurized gas from accumulator32through valve supply line34. Accumulator32is supplied by compressor30, which runs off the motorcycle electrical system. Valve20is actuated by valve pushrod22, which measures the distance between trike frame4and trike swing arm6. The length of valve pushrod22is set at the factory, and in effect determines the proper angle of trike frame4relative to the surface upon which the motorcycle rests. The indication and control system of valve20provides for a 30-35 second delay in actuation, which prevents road bumps and other temporary inputs from causing valve chatter.

In the preferred embodiment, gas shock absorber28was disposed between trike swing arm6and trike frame4, in order to provide an optimum suspension.

FIG. 3is a plan view of a schematic diagram of the instant automatically adjustable rear suspension. Compressor30supplies accumulator32, which in turn supplies valve20through valve supply line34. Valve20is mechanically connected to axle18by means of valve pushrod22. Valve20is pneumatically connected to air springs24via air spring supply lines26.

In operation, when valve pushrod22informs valve20that trike frame4is too low, the indication and control system of valve20provides for a 30-35 second delay in actuation to prevent road bumps and other temporary inputs from causing valve chatter. Following this anti-chatter delay, valve20directs compressed gas to air springs24through air spring supply lines26, thus inflating air springs24and increasing the height of trike frame4above a surface upon which the motorcycle rests. The action of raising trike frame4has the effect of changing the angle of the motorcycle relative to the surface upon which it rests, because the motorcycle will pivot about its front wheel.

When trike frame4is at the factory pre-set optimum height (and consequently the angle of the motorcycle relative to the surface upon which it rests is optimized), valve pushrod22directs valve20to cease inflating air springs24.

Similarly, when valve pushrod22informs valve20that trike frame4is too high, the indication and control system of valve20provides for a 30-35 second delay in actuation to prevent road bumps and other temporary inputs from causing valve chatter. Following this anti-chatter delay, valve20permits gas to be released from air springs24through air spring supply lines26, thus deflating air springs24and decreasing the height of trike frame4above a surface upon which the motorcycle rests. This action of lowering trike frame4has the effect of changing the angle of the motorcycle relative to the surface upon which it rests, because the motorcycle will pivot about its front wheel.

When trike frame4is at the factory pre-set optimum height {and consequently the angle of the motorcycle relative to the surface upon which it rests is optimized}, valve pushrod22directs valve20to cease inflating air springs24.

In the preferred embodiment, trike frame4, valve pushrod22, and trike swing arm6(including L arms12), were factory metal fabrications. Compressor30, accumulator32, valve supply line34, valve20, air spring supply lines26, air springs24and gas shock absorber28were commercially available components.

While a preferred embodiment of the invention has been illustrated herein, it is to be understood that changes and variations may be made by those skilled in the art without departing from the spirit of the appending claims.

DRAWING ITEM INDEX