A motorcycle windshield, or windscreen as it is also called, is a piece of accessory equipment that may be found on many motorcycles, and occasionally on bicycles, a windshield being a generally transparent guard through which the motorcyclist looks to see the road ahead. Although they are otherwise usually fully equipped when sold, most motorcycles do not come from the factory with an installed windshield and, as such, windshields are a popular after-sale accessory purchase.
Motorcycle windshields are generally mounted either on the frame or on the handlebars (the later being alternatively called "fork mounted") of the vehicle out in front of the rider. A properly designed windshield deflects at least a portion of the onrushing force of the wind over and around the rider and may additionally act to intercept and deflect small debris such as sand, pebbles, and bugs away from the rider, even small debris such as these becoming painful projectiles at highway speeds.
Broadly speaking, motorcycle windshields are of two sorts: removable and permanent. A removable windshield is one that is designed to be taken off of the vehicle and reinstalled as needed, whereas a "permanent" windshield is expected to remain installed indefinitely. In some sense, of course, all windshields are removable eventually, but the preferred removable windshield for purposes of this application is one that can be easily attached and detached from the vehicle, preferably without tools.
Many motorcyclists prefer to use windshields when making longer trips at highway speeds, but find them unnecessary--or even an annoyance--for short trips around town. This sort of rider appreciates a windshield that can be removed from the motorcycle and reinstalled as needed. However, a typical mounting arrangement for a removable windshield may require wrench tightening of at least two bolts, a fact that brings about a certain reluctance to install or remove it. Additionally, when the rider is away from home, it may be necessary to carry the tools to temporarily remove the device for local travel at a remote destination. Thus, the preferred windshield for use in this sort of situation is one that can be completely removed and reinstalled again without tools.
Additionally, other things being equal, most owners would prefer a removable motorcycle windshield that can be installed without making a permanent modification to the vehicle. In particular, some removable windshields require the installer to drill one or more holes into the frame or handlebars of the vehicle so that mounting hardware may be installed. Many riders--and especially those that drive classic or collector motorcycles--might desire to add a windshield to his or her bike, but would not do so because of the decrease in value that such permanent modifications might bring.
Further, even when the windshield does not require permanent modification to the vehicle as part of its installation, it is often the case that an otherwise easily-removed windshield will still requires some semi-permanent mounting fixtures to be attached to the vehicle, semi-permanent meaning for purposes of this application a fixture that cannot be removed without tools. In these cases it may be relatively easy to remove the shield itself, but residual mounting hardware remains attached to the vehicle thereafter. This is not only unsightly, but can make it difficult to thoroughly clean the vehicle, as road dirt inevitably accumulates around the mounting hardware.
Safety should always be a concern with motorcycle equipment and, in fact, a windshield does generally increase the safety of the rider by intercepting some small projectiles that might otherwise strike him or her. However, the use of a windshield--either permanent or removable--raises the possibility of injuries to the rider of another sort, and the preferred windshield is one that is designed to minimize this risk. In particular, when a motorcyclist is involved in an accident, it is not uncommon for the rider to be thrown forward over the front of the vehicle. In that case, the rider may impact against the windshield, thereby injuring himself or herself more than he or she might otherwise. A windshield must be solidly mounted on the motorcycle so as to resist the force of the wind and road projectiles. On the other hand, a windshield that does not "give" when a rider is thrown against it from behind can cause serious injury over and above those injuries that the rider might otherwise experience. Thus, the ideal windshield, whether removable or permanent, is one that resists blows and forces coming from the front of the vehicle and yields to blows coming from the rear of the vehicle, thereby reducing the risk of injury to the rider in certain kinds of accidents.
Another safety concern related to motorcycle windshields is that they are sometimes made of cast acrylic materials, a relatively brittle material that can shatter into jagged pieces when stressed. As might be expected, these jagged edges can pose a safety hazard to the motorcyclist in some situations. An advantage of using cast acrylic materials is that they can be easily and cost-effectively molded into almost any conceivable shape by techniques such as hot forming or vacuum forming. However, this advantage comes at the expense of an increased risk of injury to the rider.
Finally, although it is often taken for granted that a windshield should be optically transparent (or nearly so) so that the road ahead can be clearly perceived, it is quite common--in fact it is virtually the rule--that the manufacturing process introduces mild to severe optical distortions into a modern motorcycle windshield. By way of example, consider the windshield illustrated in Willey, U.S. Pat. No. 4,489,973. This windshield is typical in that it has been formed into a contoured shape, with the various contours being arranged so as to avoid, among other things, the instruments and handlebar mounts. Additionally, contouring of the windshield shape can also be used to improve its aerodynamics. However, radially molded designs such as the one illustrated in Willey, although they might be cost effective to manufacture, inevitably distort, at least somewhat, images viewed therethrough. In particular, a curved section of a windshield tends to act like a lens, causing parallel "rays" of light to either converge (concave section) or diverge (convex section). In either case, this bending of light rays results in perceived distortion to objects seen through the windshield. Further, since the head and eyes of motorcycle rider are in near constant motion (due to road irregularities, if nothing else), objects in the road ahead will be viewed at different times through different sections of the windshield (each potentially having its own radius of curvature), which creates the possibility for eyestrain and inaccurate perception. On the other hand, a planar windshield contains no such variational sources of distortion and, to the extent that the materials it is made from are optically distortionless, it will offer relatively distortionless viewing.
In the past the motorcyclist has been faced with a dilemma: he or she must either choose a windshield that is easy to attach and detach but that requires some sort of permanent hardware mount to be affixed to the vehicle, or a windshield that does not require a permanent attachment to the vehicle but is more difficult to remove. For example, Armstrong U.S. Pat. No. 5,658,035 discloses a windshield that is easy to remove, as it requires little more than slipping the device onto preinstalled bushings. However, the bushings are installed by drilling holes into the motorcycle frame, a practice that permanently defaces the vehicle. On the other hand, inventors such as Comiskey, Sr., U.S. Pat. No. 2,675,266, and Gager, Jr., U.S. Pat. No. 4,269,445, teach windshields that do not require a permanent modification to the vehicle, but which cannot be completely removed without some effort and / or tools.
Similarly, many of the prior art windshields are molded into contoured shapes (e.g., Comiskey Sr., U.S. Pat. No. 2,675,266, and Saunders, U.S. Pat. No. 4,166,650), so the prospective windshield purchaser has often had little choice but to purchase a windshield that distorts at least a portion of his or her field of vision.
Thus, what is needed is a removable motorcycle windshield that can be completely installed onto and removed from the vehicle without tools. Additionally, this windshield should require no permanent or semi-permanent mounting hardware to be attached to the vehicle. Further, the windshield should be as optically distortionless as possible and made of a material that will not shatter upon impact. Finally, the windshield should be resistant to solid blows from the front but designed to separate easily and completely from the vehicle when struck from behind, thereby tending to protect the rider in the event of an accident.
Before proceeding to a description of the instant invention, however, it should be noted and remembered that the description of the invention which follows, together with the accompanying drawings, should not be construed as limiting the invention to the examples (or preferred embodiments) shown and described. This is so because those skilled in the art to which the invention pertains will be able to devise other forms of this invention within the ambit of the appended claims.