Abstract:
A light flexible hand grip and method of making with an inner tubular core of flexible rubber with apertures formed therein and an outer tubular cover disposed over the core with a lighter weight annular flexible foam spacer between the core and outer cover. The spacer may be formed by injecting curable material through the apertures. The apertures may be formed by inserting a mandrel in the core, punching the holes and removing the mandrel.

Description:
BACKGROUND 
       [0001]    The present disclosure relates to flexible hand grips and particularly, grips of the type employed on a handle or shaft such as may be found on shovels or sporting implements such as tennis racquets and golf clubs for example. Such hand grips are typically molded of pliable or flexible material such as rubber or elastomer and assembled onto the handle or portion of the implement to be grasped manually. Hand grips for such implements have the need to be frictionally retained on the handle portion of the implement and yet need to provide a soft pliable and flexible gripping surface for the user&#39;s hand, particularly where the implement is to be moved in an arcuate or swinging motion which would create exertion by the user, as is the case with golf clubs, tennis racquets and tools such as hammers. This has necessitated forming the thickness of the hand grip to an amount sufficient to provide a soft resilient or pliable surface for the user&#39;s hand not only for providing adequate grip retention but to prevent discomfort which would cause blisters upon repeated usage. However, where the material thickness has been provided sufficient to yield a compliant or pliable soft flexible surface for the user&#39;s hand, this has resulted in the need for a substantial amount of material to be provided in the grip and has yielded a grip that added weight to the implement, increased the amount of material required and a resultant increase in manufacturing costs. 
         [0002]    Thus, it has been desired to provide a flexible pliable hand grip for use on an implement which is sufficiently soft to enable the user to grip and retain a hold on the implement during forceful movement and yet provide such a grip that requires a minimum use of material and one that is relatively light in weight. 
       BRIEF DESCRIPTION 
       [0003]    The present disclosure describes a flexible compliant hand grip for assembly onto the handle of an implement such as, for example a hammer, shovel, golf club or tennis racquet and which has an inner tubular core formed of flexible material for receiving the implement handle with an outer tubular member formed of similar flexible compliant material disposed over the inner core with an annular space provided there between which space is filled with a spacer formed of flexible material of substantially lower or reduced bulk density relative to the core and outer member. The inner core is provided with a plurality of spaced apertures through which is injected curable material for forming a filler or spacer in the annular space between the core and the outer tubular member for maintaining the outer tubular member in its position over the core. In the present practice, it has been found satisfactory to form the spacer of injectable curable foam material and to form the core and outer tubular member of flexible elastomeric material. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a cross-sectional view of an exemplary embodiment of the outer tubular member; 
           [0005]      FIG. 2  is a sectional view of an exemplary embodiment of the core member; 
           [0006]      FIG. 3  is an exploded perspective view of the tooling arrangement for punching the apertures in the core member; 
           [0007]      FIG. 4  is a cross-sectional view of an exemplary embodiment of the assembled hand grip; 
           [0008]      FIG. 5  is a portion of a cross-sectional view similar to  FIG. 1  showing an alternate embodiment of the outer tubular member; and, 
           [0009]      FIG. 6  is a portion of a sectional view similar to  FIG. 2  showing an alternate embodiment of the core member. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Referring to  FIGS. 1 ,  2  and  4 , a hand grip is indicated generally at  10  and includes a core member  12  having a generally tubular configuration with an outwardly extending flange portion  14  formed on one end thereof with the outer face  16  optionally tapered and, if desired, the flange  14  may include an annular undercut  18  to provide radial resiliency and facilitate manufacture of the grip  10 . The core member  12  may include an annular rib  20  on the inner periphery thereof in proximity of the end remote from the flange  14 . 
         [0011]    Referring to  FIG. 1 , the outer tubular member  22  is shown as having a closed end  24  provided with a vent hole  26  extending through an inwardly extending projection  28  which may have an annular or circumferential groove  30  formed therein to be engaged by the rib  20  in the core member upon assembly. The outer tubular member  22  may also be provided with an inwardly extending annular rib  32  adjacent the end opposite the closed end  24  which rib  32  is operative to engage an annular groove  36  formed in the outer periphery of the flange  14  of core  12  as shown in the assembled condition in  FIG. 4 . 
         [0012]    Referring to  FIG. 2 , the core member has a plurality of spaced apertures  38  formed through the wall thereof in a manner as will hereinafter be described in further detail. 
         [0013]    Referring to  FIGS. 5 and 6 , alternate exemplary embodiments of the ends of the core  12  and outer tubular member  22  are shown wherein the tubular member  122  has the end face  124  thereof provided with an inwardly extending projection  128  which has an annular taper  130  provided thereon. The corresponding embodiment  112  of the core member has the end thereof provided with a tapered surface  120  on the inner periphery thereof which engages the tapered surface  130  on the outer tubular member as shown in  FIG. 4 . 
         [0014]    Referring to  FIG. 3 , the core member  12  is shown positioned to have a mandrel  40  with relief holes or apertures  42  formed therein which are sized and located to correspond with the apertures  38  provided on the core  12  with the mandrel inserted into the core member  12  and positioned such that the holes  42  align with the respective apertures  38  in the core member. 
         [0015]    A plurality of punches indicated generally at  44  are positioned adjacent the core member  12  and guided by guide blocks  46 . The punches  44  are then urged into contact by the drivers  48  which may comprise any convenient mechanical, hydraulic, electrical or pneumatic device such that the punches form the apertures  38  in the core member with the material removed, or plugs, passing to the interior of the mandrel  40  through apertures  42 . The material removed by formation of the apertures  38  may then be removed from the mandrel  40  by any suitable expedient, for example, blowing through with compressed air. Upon completion of the punching operation, the mandrel  40  is then removed from the core member  12 . 
         [0016]    It will be understood that the punching operation the apparatus illustrated in  FIG. 3  is performed on the core member  12  prior to assembly with the outer tubular member. 
         [0017]    Referring to  FIG. 4 , the annular space between the outer tubular member  22 ,  122  and the core  12 ,  112  is filled with suitable lightweight material or material having a bulk density substantially less than that of the outer tubular member or core as denoted by reference numeral  50 . In the present practice, it has been found satisfactory to insert curable material through the apertures  38  in the core member and it has been found particularly satisfactory to inject curable foam material through the apertures  38  to form the spacer  50  in the annular space between the core and outer tubular member. Thus, the lightweight curable material, once cured, provides a resilient support for the relatively thin wall of the outer tubular member, thereby providing adequate cushioning and “feel” to the hand grip when grasped by the user&#39;s hand. 
         [0018]    In the present practice it has been found suitable to employ ethylene-propylene-diene-monomer (EPDM) material and particularly EPDM foam material for the spacer  50 . In the present practice, it has been found satisfactory to form the spacer  50  of curable material having a specific gravity in the range of about 0.1 to 0.7 and having a durometer in the range of about 20-50 on the Shore ‘A’ scale. However, it will be understood that other suitable injectable curable lightweight materials with adequate flexibility for supporting and flexibly cushioning the outer tubular member may also be employed. 
         [0019]    In the present practice, it has been found satisfactory to form the core member  12 ,  112  and the outer tubular member  22 ,  122  of flexible elastomeric or rubber material. In particular, it has been found satisfactory to form the core member of material having a specific gravity in the range of about 0.8 to 1.5, of material having a durometer in the range of about 35 to 75 on the Shore ‘A’ scale and a material having the combination of both. In the present practice, it has also been found satisfactory to form the outer tubular member of flexible material having a specific gravity in the range of about 0.8-1.5, of material having a durometer in the range of about 35 to 75 on the Shore ‘A’ scale and of material having both properties. However, it will be understood that other materials may be employed as desired for providing adequate gripping by the user and the desired flexibility and “feel” when gripped sufficiently to retain control of an implement upon which the grip is affixed during rapid or forceful movement thereof. 
         [0020]    It will be understood that although the hand grip illustrated herein is shown having the inner diameter of the core member relatively small compared to the outer diameter of the tubular member, as would be the case for a golf club hand grip, that the proportions may be changed to accommodate larger size implements to be gripped such as would be the case for a hand grip for an implement such as a hammer, sledge hammer or shovel. 
         [0021]    The present disclosure thus describes a flexible relatively soft hand grip for an implement which is light in weight by virtue of a resilient foam facer between the core and outer tubular portion formed in material significantly lighter than the core or outer tubular portion. 
         [0022]    The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.