Background of the Invention
The present invention relates to resilient seat mounting means particularly adapted to motorcycle and tractor seat mountings whereby a plurality of rubber-like pads are placed between rigidly interconnected members to restrict and dampen the transmission path of vibration to the seat.
Description of the Prior Art
The present invention is conceived to supplement and complement existing means of providing a reduction in the transmission of vibration from the chassis of a motorcycle or tractor to the seat through the supporting members of the seat. The invention does not contemplate the reduction of large shocks, that being the function of the normal seat cushioning or springs; however, as will be evident from the following disclosure, the present invention will also dissipate the stress on structural members to some degree with respect to large shocks. The vibration absorbing pads and the relative placement thereof are contemplated to primarily reduce high frequency vibration transmitted to the seat from the motor, drive chains and sprockets which, for example, which can cause driver fatigue and discomfort.
Although numerous patents have been directed to the construction of motorcycle and tractor seats, the inventor herein knows of only one patent having relevance to the present invention, that being U.S. Pat. No. 2,303,567. This patent discloses a resilient seat mounting having two resilient rubber discs interposed between a mounting seat post and mounting seat bracket such that shocks transmitted between the post and seat are resisted, absorbed and dampened by the torsional and shear stresses inherent in the rubber compound.
The primary distinction between U.S. Pat. No. 2,303,567 and the present resilient mounting means is that the former is designed to primarily absorb for large shocks while the latter is to attenuate for high frequency vibration. In the former, high frequency vibrations from the motor drive chains, sprockets and gears may still be transmitted to the seat through the brackets attached to the seat bottom. Thus it is contended that the present invention could be applied in combination with above-cited disclosure to further improve the performance of the former invention.
The present invention may be incorporated into existing motorcycle seats inexpensively as only a slight alteration of existing parts is contemplated. The invention simply consists of a kit of pads formed from a durable rubber-like compound which interface supporting seat frame members and securing components to intercept and to interrupt the transmissability of vibration to the seat, and includes one modified seat support frame member and two bolt extensions.
Summary of the Invention
The object desired to be attained by the present invention is the isolation of the seat of a motorcycle or tractor from vibration and especially, from high frequency vibration transmitted from the motorcycle or tractor chassis from the motor drive chains, sprockets and gears through a main seat support member and the other related seat support frame members. This goal is accomplished by interposing resilient rubber-type compound pads primarily between members which transmit vibration to other members which receive and further transmit the vibration to the seat. Furthermore, bolts which interconnect the supporting members are also dampened with respect to vibration transmission, by the placement of the resilient pads through which the bolts protrude.
Generally, the invention contemplates the positioning of a kit of the vibration absorbing pads between the main support bar and support members attached to the seat bottom. Resilient pads may be further positioned so the bolt head and securing nut and washer combinations will both be interfaced to the supporting members by the pads. Not all bolt/or nut-washer and support member connections need be interfaced by a resilient vibration absorbing pad, however, if the connection is not in direct relation to the transmission path of vibration to the seat and if the bolt is adequately dampened by other absorbing pads. Use of this kit, in the preferred embodiment, requires modification to one seat support frame member and two bolt extensions. This feature and further features may be more adequately related and described in regard to the following drawing and description thereof.
Brief Description of the Drawing
FIG. 1 illustrates an exploded perspective view of a motorcycle seat and support structure embodiment incorporating the kit of resilient vibration absorbing pads in accordance with the principles of the present invention.
FIG. 2 is a perspective view of a typical resilient vibration absorbing pad used in the kit of this invention.
Description of the Drawings
Illustrated in FIG. 1 is a standard motorcycle seat 10 and its related supporting structure members as seen in a perspective exploded view, the phantom lines illustrating the relative position of the assembly members. Longitudinal T-shaped main support bar 12, which attaches at its forward extent to the motorcycle chassis, provides the main support for seat 10, its integrated rear transverse frame member 13 attaching to rear seat support flanged bracket bar 14. Flanged support bracket 14 is affixed to seat 10 or may form a unitary seat super-structure. Forward seat tongue support member 16 is angularly secured to bridge the forward seat portion to an intermediate aperture 18 on main support bar 12. Forward seat tongue support member 16 is, in the preferred embodiment, the only seat frame support member which requires modification to accommodate the kit of vibration absorbing pads. Tongue support member 16 must be enlarged at its forward extent. A rear rack attaching bracket 20 may be interposed between main support bar 12 and flanged support bracket 14.
Most of the vibrations transmitted to seat 10 will proceed from the forward portion of main longitudinal T-support bar 12 to flanged support bracket 14 due primarily to the rigidity of the connection needed to provide the main support for a rider's weight.
As a result vibration absorbing pads are placed to in effect sandwich both flat surfaces of main support 12 to reduce the vibrational level between it and the other supporting members 14 and 16 and the interconnecting bolts and nuts.
The kit of vibration absorbing pads of the present invention, of which pad 30 of FIG. 1 is an example, are dimensioned to conform in size and shape to the support member portion which the pad will abut. The pads therefore are substantially rectangular. The pads will be of a size large enough to adequately contain at least one aperture 32 of a diameter commensurate with the diameter of the securing bolt to secure a tight fit.
The rear seat support connection of flanged bracket 14 and the transverse frame member 13 of main longitudinal support bar 12 is accomplished by sandwiching said transverse member 13 between double upper absorbing pads 44 and 46 and lower absorbing pads 30 and 34. Vibration absorbing pads 44 and 46 interpose main support bar transverse frame member 13 and flanged support bracket 14, and are of a double thickness. Bolts, collectively numbered 50, extend through the assembly. Nuts and washers, collectively numbered 54, secure the assembly and abut absorbing pads 30 and 34.
It should be noted that it is not critical that vibration abosrbing pads be placed between main support bar transverse section 13 and rear rack support brackets 20 since brackets 20 do not in themselves transmit vibration to seat 10 by a rigid connection, but do transmit to the rack which supports it. However, if desired vibration absorbing pads could be placed to interpose these members.
Thus all pads, since they snuggly fit the shafts of bolts 50, act to reduce the transmission of vibration by the bolts. Together the pads reduce the vibrations incrementally with lower pads 30 and 34 initially absorbing some of the vibration. Double pads 44 and 46 act to complete the reduction of vibration transmission into and through flanged bracket 14.
Turning now to the forward seat portion, forward seat angled tongue support member 16 is a replacement and a variation of for the standard part, the changes being an enlargement of its forward end to provide for the insertion of an absorption pad within the forward end and allow two bolts 56 to pass therethrough to isolate said bolts from the tongue. Tongue support member 16, in the preferred embodiment has a rectangular shaped aperture 17 into which is inserted a vibration absorbing pad 57. Two vibration absorbing pads 59 and 60 sandwich the front end of seat support tongue 16, of which pad 59 is a double pad. Because of the thickness of pads 59 and 60, bolt-extensions 58 are used to extend bolts 56. Washers and nuts 61 complete this assembly. Two absorbing pads 62 and 64 encompass the surfaces of the rear of support tongue 16 to isolate it from bolt 68 and support bar 12. To further reduce the vibrations transmitted along main support bar 12, pad 66 conforming to the shape and diameter of aperture 18, is inserted within the aperture. This pad esspecially reduces the vibrational transmissability of securing bolt 68, which eliminates the need of placing a pad between bolt head 70 and tongue support 16. Nut and washer 72 complete this assembly. Absorbing pad 64 is especially helpful in reducing transmission to main support transverse section 13 in combination with the other two pads 62 and 66. It is further not always deemed necessary to place an absorbing pad between the nuts and washers, numbered 61, which abut tongue support 16 where it connects with seat 10. Thus if it is not desired to alter the tongue support frame member, although vibration isolation is not as effective, a pad may simply be placed between seat 10 and tongue 16.
Referring now to FIG. 2, a typical vibration absorbing pad 80 is illustrated. This pad is sold under the registered trademark ISOMODE by Gilmore Industries Inc., Cleveland, Ohio. The vibration absorbing pads 80 contemplated to be used in the present invention should be rubber-like and may be constructed from neoprene for example. Their hardness should range from a static loading of 50 to 150 pounds per square inch. The pads may have flat surfaces; however, best results are obtained if the opposing surfaces have contoured ridges, each surface having the ridges running transverse to the other. The pads should have a durometer of 45.
The present invention therefore inhibits the transmission of vibrations from one supporting member to another which would be effected by direct contact of the members or through a securing bolt. The vibration absorbing pads isolate the areas which would transmit vibrations, and by placing several pads in the line of transmission, the reduction will occur incrementally. It is recognized that the present invention may be adapted to various types of motorcycle and tractor seats. The prime criteria are that all interfacing supporting members of the seats have absorbing pads interposed therein and that the pads sufficiently interrupt all direct transmission paths including bolt heads and nut attachments.
It is thus desired that the present invention not be strictly limited to the foregoing disclosure and that modifications and variations may be derived therefrom without departing from the spirit and scope of the following claims.