Abstract:
A hand tool includes a work portion and a user/operator interface portion comprising a handle. The handle comprises a pair of elongated members each including a generally I-shaped cross-section. Each elongated member includes a gripping portion. The gripping portion has a first surface and a primary user-interface surface having curvatures in three dimensions and preferably defined by a plurality of constant radii. As such, the handle conforms to the hands of a user/operator and reduces or eliminates undesirable pressure concentration points. The first surface of the gripping portion is provided with a finger registration portion which receives and positions the fingers of the operator around the gripping portion. The hand tool more efficiently transfers the operator input force through the hand tool to a workpiece and provides an improved comfort to the operator.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This present application claims priority of provisional application Ser. No. 60/848,858, titled “Hand Tools and Handles Therefor” filed on Oct. 2, 2006, the contents of which are incorporated by reference herein in its entirety. 
    
    
     FIELD 
     The present disclosure generally relates to hand tools and the interface by which a user/operator manipulates the tools such as, for example, handles. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     Hand tools generally comprise a work portion (i.e., that portion of the tool which interfaces with a workpiece or the like) and a user interface portion (i.e., that portion of the tool which the user/operator manipulates). It is well-known in the manufacture of hand tools to produce a hand tool from a steel stamping or a forging in order to create a desired work portion for the tool. It is further commonplace to coat the user interface portion of the tool with a soft plastic. In such hand tools, however, the user interface is not optimized to maximize the efficiency of the tool and the comfort to the user/operator. 
     In a hand tool, it is desirable to obtain the most efficient transfer of the force that is applied by the user/operator of the tool to the workpiece upon which the tool is acting. Simultaneously, it is desirable to minimize any discomfort experienced by the user/operator during use and manipulation of the tool. Consequently, a hand tool that possesses the appropriate strength and rigidity while improving the tactile feel and feedback for the user is sought after. Moreover, it is desirable to keep the weight of a hand tool to a minimum while maximizing its strength and its ability to transfer the maximum amount of force from the user to the workpiece. 
     SUMMARY 
     In one form, a hand tool includes a work portion adapted to interface with a workpiece, and a handle connected to the work portion. The handle includes a primary user-interface surface. The primary user-interface surface receives a force applied by a user so that the work portion can perform work on the workpiece. The primary user-interface surface has curvatures in three dimensions. 
     In another form, a handle for a hand tool includes a gripping portion. The gripping portion includes a primary user-interface surface to which a force is applied by a user so that the hand tool can perform work on a workpiece. The primary user-interface surface has curvatures in three dimensions. 
     In still another form, a crimping hand tool includes a work portion and a handle connected to the work portion. The work portion is configured to surround a tubular workpiece. The handle includes a pair of gripping portions each having a primary user-interface surface and a first surface opposite to the primary user-interface surface. The first surface defines a finger registration portion. The primary user-interface surface is formed from a contour defined by a plurality of constant radii. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is a perspective view of a crimping hand tool constructed in accordance with the teachings of the present disclosure; 
         FIG. 2  is an enlarged, partial front view of the hand tool of  FIG. 1 , showing details of a handle; 
         FIG. 2A  is a cross-sectional view along the line  2 A- 2 A of  FIG. 2 ; 
         FIG. 3  is an enlarged, partial top view of the hand tool of  FIG. 1 , showing details of the handle; 
         FIG. 4  is a partial side view of the hand tool of  FIG. 1 , showing a handle; and 
         FIG. 5  is a front view of a crimping hand tool according to another form of the present disclosure. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. While reference to the subject invention is made herein in the context of a crimping hand tool, it should be understood and appreciated that the features and attributes described in the present disclosure may be employed in any of a variety of hand tools and are not limited to the device illustrated and described herein. 
     Referring to  FIG. 1 , an exemplary hand tool in the form of a crimping hand tool constructed in accordance with the teachings of the present disclosure is illustrated and generally indicated by reference number  10 . The crimping hand tool  10  includes a work portion  12  and a user/operator interface portion  14 . The work portion  12  in this exemplary embodiment is a crimping portion and the user/operator interface portion  14  is a handle. 
     The work portion  12  includes a pair of jaws  16  cooperatively defining a crimp ring holding space  18  therebetween. The jaws  16  are pivotably connected at the pivot points  20 . The crimp ring holding space  18  can be enlarged as the jaws  16  move away from each other, so as to receive a crimp ring (not shown) therein. As the jaws  16  are moved toward each other, the jaws  16  create a crimp on the crimp ring so as to secure a fitting (not shown) to a tube (not shown). 
     The jaws  16  are connected to a linking member  22 . The linking member  22  is provided with a pair of stubs (not shown) embedded in the handle  14 . The handle  14  is attached to the work portion  12  at the stubs. One manner of attaching the handle  14  to the work portion  12  is by injection molding the handle  14  around the stubs. 
     Optionally, an adjustable lock screw  23  may be mounted to the jaws  16  for tool calibration as shown in  FIG. 5 . 
     Referring to  FIGS. 1 to 4 , the user/operator interface portion comprises a handle  14  that includes a pair of elongated members  24  attached to the work portion  12 . The two elongated members  24  are configured and disposed in a mirror image orientation relative to a longitudinal axis X of the crimping hand tool  10 . Each of the elongated members  24  is to be held in the hand of a user/operator. The elongated members  24  each have a head portion  26  that engages the linking member  22 , a gripping portion  28  to enable a user/operator to grip the hand tool, and a transition portion  30  located therebetween. The handle  14  has a front surface  32  and a back surface  34 . The gripping portions  28  each have a first surface  36  and a second surface  38  opposite to the first surface  36 . The first surfaces  36  of the gripping portions  28  face to each other. 
     The elongated members  24  comprise a generally I-shaped cross-section (see  FIG. 2A ) which creates an elongated recess  40  on each of the front surface  32  and the back surface  34  of the handle  14 . The I-shaped cross-section is preferably formed at the gripping portions  28  and the transition portions  30  so that the elongated recesses  40  extend along the length of the gripping portion  28  and the transition portion  30  to define a web portion of the I-shaped cross-section. The first surface  36  and the second surface  38  are disposed at the opposite ends of the I-shaped cross-section with the web portion disposed therebetween. The I-shaped cross-section provides improved rigidity and strength for the elongated members of the handle  14 . This rigidity and strength results in any force applied to the handles  14 , for example by the user/operator, being more efficiently transferred to the work portion  12  of the hand tool. 
     Each head portion  26  is provided with a stop  27  extending inwardly of the hand tool toward the other stop  27 . The stops  27  limit the movement of the elongated members  24  toward one another. In addition, the stops  27  contribute to the tactile response and “feel” of the hand tool to the user/operator. As shown, the stops  27  are generally triangular in shape; however, the size and shape of the stops  27  may be varied as desired to produce a different feel for the hand tool  10 . For example, varying the size and/or shape of the stops  27  may increase or decrease their resiliency and change the way in which the applied forces to the hand tool are opposed. As such the tactile response experienced by the user/operator can be varied. 
     The gripping portions  28  are contoured to comfortably conform to the hand and grip of a user/operator of the hand tool. When the user grips the gripping portions  28 , a significant area of the user&#39;s palms are in contact with the second surfaces  38  of the gripping portions  28 . Therefore, the second surfaces  38  function as primary user interfaces and receive a force applied by the user so that the work portion  12  can create a crimp on the crimp ring. It should be understood and appreciated that the work portion  12  of the hand tool can perform different work on the workpiece that interfaces with the work portion  12 , depending on the types of the hand tools. For example, the work performed on the workpiece can be cutting, bending, drilling, punching, and forging, depending on the types of the hand tools. 
     The second surfaces  38  have curvatures in three dimensions (e.g., the surfaces are curved in the X-Y, X-Z, and Y-Z planes). Preferably, the second surfaces  38  are formed from a plurality of constant radii R 1 , R 2 , and R 3 . R 1 , R 2  and R 3  may be equal or different. With the constant radius configuration, the reaction force to the force applied to the handle by the user/operator is more evenly and comfortably distributed to the hands of the user/operator, and any pressure concentration points on the gripping portions  28  of the handle  14  are reduced or eliminated. As such, discomfort, pain and fatigue to the user/operator are likewise reduced or eliminated. 
     The first surface  36  of the gripping portion  28  is provided with a plurality of evenly spaced ridges  42  extending along the gripping portion  28 . Recesses  44  are formed between the ridges  42 . The recesses  44  and the ridges  42  combine to form finger registration locations to enable the proper and comfortable positioning of the user/operator&#39;s fingers while using the hand tool. When an user/operator&#39;s fingers are in the registration locations, the elongated recess  40  further provides additional space where the user/operator&#39;s finger tips may extend, if necessary. Consequently, the user/operator&#39;s hands and fingers are more properly and comfortably positioned and supported around the gripping portions  28 . Moreover, with the described construction, the force applied by the user/operator can be more comfortably applied to the hand tool. Undesirable pressure concentration points and user/operator fatigue, therefore, may be reduced or eliminated. 
     The handle is preferably made of lightweight, durable polycarbonate material, such as a 30% glass-filled polycarbonate. As a result, the handle may be more than 20% lighter than a handle of a traditional hand tool. In addition, the design of the handle enables the amount of material necessary to manufacture the handle to be reduced. Such a reduction reduces the raw material cost associated with the manufacture of the hand tool. 
     With the construction of the hand tool described in the present disclosure, the hand tool is light weight, but yet has increased mechanical strength and efficiency. Moreover, the constant-radius contour of the handle in three dimensions, coupled with the finger registration locations, enable the user/operator to comfortably and efficiently use the hand tool. 
     It should be noted that the handle described in the present disclosure may be used in a variety of hand tools besides the specific crimping tool shown. Moreover, while the handle has been described to have a pair of gripping portions, it is within the scope of the present disclosure that the handle may have only one gripping portion and be operable by one hand. Accordingly, the description of the present disclosure is merely exemplary in nature and, thus, variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure.