Patent Publication Number: US-2003226421-A1

Title: Shock absorbing handle bar grip

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] This invention relates to a shock absorbing grip having particular application for surrounding the opposite ends of metal handle bars of a bicycle, or the like, to minimize the shock that is transmitted from the handle bars to the hands of a rider while riding his bicycle over a rough or bumpy terrain.  
       [0003] 2. Background Art  
       [0004]FIG. 1 of the drawings shows a portion of a typical bicycle  1  having a pair of metal handle bars  3  to be grasped by the rider to enable him to improve his balance and control the direction in which the bicycle will travel. The end of each of the handle bars  3  is commonly surrounded by a grip  5 . The grips  5  at opposite ends of the handle bars  3  are held in place by means of a snug friction fit. The grips  5  establish a convenient and comfortable location around which the rider can wrap his hands to gain a firm grasp of the handle bars  3 .  
       [0005] As will be known to riders of all ages, a bicycle may often travel over rough and bumpy terrain. The impact forces that are generated as the bicycle wheels ride over such terrain are transmitted to the hands of the rider in the form of shock waves that are propagated along the bicycle frame  7  and the handle bars  3  to the grips  5 . Under certain conditions, the magnitude of the shock waves reaching the rider&#39;s hands can result in a steady vibration and discomfort over time. In other cases, the shock waves may interfere with the rider&#39;s ability to control his bicycle.  
       [0006] Accordingly, it would be desirable to have available a handle bar grip to fit over each end of the handle bars  3  of the conventional bicycle  1  so as to reduce the magnitude of the impact forces and the vibrations that are transmitted to the hands of the rider to thereby increase the comfort of his ride and maximize his ability to control the bicycle.  
       [0007] One example of a bicycle handle bar grip that is manufactured from inner and outer layers of material having different densities is available by referring to U.S. Pat. No. 6,112,618 issued to P. M. Yates.  
       SUMMARY OF THE INVENTION  
       [0008] A cylindrical shock absorbing handle bar grip is disclosed of the kind that surrounds each of the opposite ends of the metal handlebars of a bicycle, or the like, to be grasped by the hands of a rider. The bicycle grip of this invention includes an inner elastomeric layer that is surrounded by and bonded to an outer elastomeric layer. The inner elastomeric layer is denser than the outer elastomeric layer by a ratio of at least 2 to 1. The boundary region between the inner and outer elastomeric layers has an irregular, cylindrical configuration. More particularly, the boundary region of the bicycle grip includes successive V-shaped pairs of faces, where one face of each pair of faces is aligned with the opposing face to make an angle of approximately 60 degrees. By bonding the inner and outer elastomeric layers of the handle bar grip to one another along an angled boundary region, the majority of the shock waves that are transmitted from the metal handle bars will be reflected by the V-shaped faces of the boundary region in a direction away from the rider&#39;s hands. By virtue of the foregoing, the rider&#39;s hands will feel less of the vibrations that are generated when the wheels of the rider&#39;s bicycle travel over a rough or bumpy terrain. Accordingly, the rider will be provided with a more comfortable grasp of the handle bars and the ability to better control the operation of his bicycle. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0009]FIG. 1 shows the handle bars of a bicycle to which the shock absorbing handle bar grips of this invention are applicable;  
     [0010]FIG. 2 shows the cross-section of a conventional handle bar grip taken along lines  2 - 2  of FIG. 1; and  
     [0011]FIG. 3 shows the cross-section of the shock absorbing handle bar grip which forms this invention. 
    
    
     DETAILED DESCRIPTION  
     [0012] Turning now to FIG. 2 of the drawings, there is shown the cross-section of a conventional grip  10  of the type that has heretofore been used to cover the opposite ends of the metal handle bars  12  of a bicycle, or the like, such as that shown in FIG. 1. In many cases, the conventional grip  10  is manufactured from a single continuous elastomeric and/or plastic material. In other cases, like that shown in FIG. 2, the grip  10  is manufactured from inner and outer layers  14  and  16  having a boundary or interface  17  lying therebetween.  
     [0013] In either case, the boundary region  17  located between the inner and outer layers  14  and  16  is uniformly cylindrical in shape. That is to say, the boundary region  17  forms a smooth, regular surface at the interface of layers  14  and  16 . Consequently, the majority of the shock waves (e.g. designated  18  in FIG. 2) that are propagated along the metal handle bars  12  are transmitted through layers  14  and  16  as well as the regular cylindrical boundary region  17  lying therebetween. While some of the shock waves  18  are intercepted and randomly reflected by the cylindrical boundary region  17 , there is nothing in the conventional handle bar grip  10  to control the direction in which the shock waves are reflected so as to prevent their transmission to the hands of the rider. Thus, and as pointed out above, the hands of the rider will be subjected to vibrations which can adversely affect the comfort of his grip and his ability to control the operation of his bicycle.  
     [0014]FIG. 3 of the drawings shows the improved shock absorbing handle bar grip  20  which forms the present invention and overcomes the inherent problems with the conventional grip  10  that was described above when referring to FIG. 2. The shock absorbing handle bar grip  20  has a cylindrical configuration and includes inner and outer elastomeric layers  22  and  24 . By way of example only, the elastomers from which the inner and outer layers  22  and  24  of grip  20  are manufactured are sold under the trademarks KRATON by Shell Oil Company or SANTOPRENE by Monsanto Company.  
     [0015] The inner elastomeric layer  22  of handle bar grip  20  is relatively dense and firm so as to establish a close and reliable friction attachment of grip  20  around the metal handle bar  12  of a bicycle. The outer elastomeric layer  24  of grip  20  is relatively soft so as to provide a comfortable feel when the handle bar grip  20  is in the grasp of the rider. Preferably, the inner elastomeric layer  22  of grip  20  is at least twice as dense as the outer elastomeric layer  24 . More particularly, the inner elastomeric layer  22  has a durometer of about 60, and the outer elastomeric layer  24  has a durometer of about 25.  
     [0016] During manufacture of the shock absorbing handle bar grip  20 , the inner elastomeric layer  22  is initially formed by pouring the elastomer into a suitable mold (not shown). While the temperature of the inner layer is raised to about 800 degrees F., the outer elastomeric layer  24  is formed by injecting the elastomer into the mold. Suitable pressure is then applied to the inner and outer elastomers. The combination of heat and pressure causes the inner and outer elastomeric layers  22  and  24  of handle bar grip  20  to be molecularly interlocked and bonded together along a continuous boundary region  26 .  
     [0017] As an important detail of the shock absorbing handle bar grip  20  of FIG. 3, the aforementioned boundary region  26  between the inner and outer elastomeric layers  22  and  24  is irregular. That is, the boundary region  26  includes successive V-shaped pairs of faces, where one face of each pair of faces is aligned with the opposing face so as to make an angle of approximately 60 degrees. By virtue of bonding the inner and outer elastomeric layers  22  and  24  of the handle bar grip  20  to one another along an irregular (i.e. angled) shaped boundary region  26 , the surface area of the boundary region  26  will be increased so that a majority of the shock waves (designated  30 ) that are transmitted from the metal handle bars  16  are more likely to be reflected by one of the angled faces  28 . The angle shaped boundary region  26  enables the direction of reflection to be more effectively controlled, whereby the reflected shock wave  30  will be directed back towards the metal handle bars  12 . The principal component of the shock wave  30  continues to be reflected between the angled boundary region  26  and the metal handle bars  12  so as to be absorbed within the dense inner elastomeric layer  22  and therefore substantially dissipated by the shock absorbing handle bar grip  20 . Thus, the magnitude of any shock waves  28  that are transmitted through the angled boundary region  26  and outwardly of the outer elastomeric layer  24  will be significantly reduced.  
     [0018] Accordingly, the rider&#39;s hands will feel less of the vibrations that are generated when the wheels of the rider&#39;s bicycle travel over a rough or bumpy terrain. In this same regard, the rider will be provided with a more comfortable grasp of the handle bars  12  and the ability to better control the operation of his bicycle.  
     [0019] Although the shock absorbing handle bar grip of this invention has particular application for reducing the transmission of shock waves propagating along the handle bars of a bicycle, it is to be expressly understood that the shock absorbing grip herein disclosed is also adapted to fit over and surround other tubular bodies along which mechanically generated and transient vibrations are normally transmitted to the hands of a user. Such bodies to which the grip of this invention is also applicable include, but are not limited to, golf clubs, baseball bats and the handle bars of motorcycles, scooters and the like.