Abstract:
An improved hand-held implement is provided with a body having external surfaces that define contours which match and ergonomically engage the surfaces of a user&#39;s thumb and fingers when the user grasps the implement, so as to provide a large surface area of contact between the user&#39;s hand and the implement. The increased area of contact between the user&#39;s hand and the implement, compared to traditional designs, decreases the required level of applied unit area pressure, and also provides for greater control consequently facilitating manipulation of the implement. The exterior of the implement is sufficiently small so that, while in use, the body of the implement does not extend outside or beyond the hand of the user. The cartridge includes a coaxial retention ring device which readily fits into the body of the implement by the resilient engagement of the ring into the coaxial recessed groove in the implement body. The implement is further provided with a spring operated mechanism for extending and retracting the tip from the cartridge. The outer surfaces of the implement, having relatively smooth flat surface, are well-suited for application of art work, logos and graphics for advertising and promotional purposes.

Description:
FIELD OF THE INVENTION 
   The present invention is directed to a small implement to be held in one&#39;s hand, as might be typically used for writing, with a readily removable cartridge. Examples of such implements include writing implements such a pens and pencils, cutting implements such as knives, awls and scribes, and other hand-held implements such as brushes, cosmetics applicators, soldering devices and computer styluses. 
   BACKGROUND OF THE INVENTION 
   In the past, traditional hand-held implements, such as those commonly used for writing, have generally been provided with a cylindrical shaft which is manipulated by the thumb and index finger of the user acting in conjunction with each other to control the tip of the device so as to accomplish a specified task. Additionally, the users of such traditional cylindrical shaft implements may often utilize the arch as a lever against the working thumb and index finger as a fulcrum, in order to manipulate the implement. Examples of such traditional single tip hand-held implements are writing instruments such as pens and pencils, cutting instruments such as knives and awls, tools such as soldering devices and scribes, painting instruments such as brushes, cosmetics application equipment and digitalizing contacting devices such as computer styluses. During their use, the surface of such traditional implements contacts a relatively small surface area of the user&#39;s skin. 
   Historically, improvements to such traditional hand-held implements concerned the mechanical aspects of the implements, such as new inks, ink flow mechanisms and delivery of the ink to the writing surface. A fundamental disadvantage of traditional implements is that they have only a single rigidly mounted working tip and the ubiquitous cylindrical shaft does not conform well to the surfaces of the user&#39;s fingers, palm or closed inner hand. 
   One of the least developed areas of hand-held implement design is the relationship between the grasping shape of the implement and the natural shape of the user&#39;s hand. This has a significant effect on the user&#39;s comfort and ability to control and manipulate the implement, particularly when the implement is to be used for a prolonged period of time. Conventional implements contact a relatively small proportion of the surface area of the user&#39;s fingers, leaving a large area of the thumb and fingers unused. Further, the bulk of the user&#39;s hand is not used to dissipate the physical stress that accompanies the use of the hand-held implement. This situation eventually leads to discomfort for the user over a period of use, as the rigid surfaces of the implement exert pressure (in the form of negative leverage) and friction on the user&#39;s fingers. Thus, it is advantageous that a larger percentage of the surface area of the hand and fingers which work with a hand-held implement should contribute to controlling the hand-held implement. 
   Prior attempts were made to modify hand-held implements to reduce discomfort and fatigue. For example, implements have been produced which have soft rubber coating materials. However, such materials tend to reduce the control of the implement in the hand and easily become soiled. Also, it has been proposed to provide hand-held implements with different concave surfaces. However, these concave surfaces have not overcome the basic problems arising from the basic idea of a cylindrical shaft oriented to extend in a direction between the thumb and index finger of the user and out away from the hand. 
   Rubin, in U.S. Pat. No. 5,785,443, described a handheld writing instrument with a similar body shape. However, Rubin&#39;s design lacks any mechanism for variably extending the implement tip from the main body and retracting the implement tip into the main body. This inability is a major disadvantage, for example, preventing a pen from being stored in a pocket without risking damage to clothing and preventing the inadvertent marking on surfaces other than the target area. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to providing an ergonomic hand-held implement with a removable cartridge and a retractable tip implement. 
   Another object of the invention is to provide a ergonomic hand-held implement which can be held with a high degree of comfort for long periods of time with reduced fatigue of the hand. The present invention will provide an ergonomic hand-held implement which provides less friction and pressure on the contacting surfaces of the hand, thereby reducing the development of blisters or calluses on the fingers or hand, for example, along the third finger which result from friction and pressure during extended use. 
   Another object of the invention is to provide an ergonomic hand-held implement which allows for performing manual activity with a high degree of precision. The present invention provides an ergonomic hand-held implement of smaller dimensions, but which provides a greater proportion of it&#39;s surface in contact with the hand, thus enabling a greater degree of control and manipulation while simultaneously providing for greatly increased comfort. 
   The present invention accomplishes these and other objectives by providing a hand-held implement which has a cartridge and cartridge housing from which a working tool extends and retracts, for example, a pen or pencil point, independent of the structural mounting requirements of the working tip. Thus, the implement can then be provided with an ergonomically shaped body, with the body preferably having a forward surface and an opposing rearward surfaces, and contiguous and generally perpendicular thereto, first and second side surfaces. The forward, rearward, and two side surfaces define a round bulb-shaped top portion and a contiguous narrower bottom portion. The top portion is ergonomically contoured so as to be fitted within the palm of a user. One of the side surface is adapted to engage the thumb of a user and the other is adapted to engage the middle finger of the user. The forward surface is adapted to be engaged by the index finger of the user, and the surfaces are oriented so that in use the implement extends in a direction which is no further toward the user&#39;s thumb than the user&#39;s index finger. The implement is of sufficient size so that the implement fits comfortably in the palm and does not extend outside the palm of the user, such that the instrument provides a greater conformation with the contours of the thumb, second and third fingers of the hand, and the closed palm, when the implement is in the position in which the device is used. In so doing, a relatively large contact area exists between the hand and the instrument. The increased area of contact decreases the pressure at any given point of contact, and the increased area of contact also allows for greater control of the instrument. The instrument of the present invention may be advantageously used in multiple manually performed activities utilizing hand-held instruments, including for example, writing, painting, cutting, soldering, surgery, and cosmetics application by simple replacement of the cartridge. 
   The present invention will satisfy the above described needs yet it is an improved design over previous ergonomic designs because it incorporates a retractable tip mechanism. In the present invention, a spring loaded plunger incorporating a dual position chevron shaped cam way is advanced upon the press of a button so as to apply an axial force upon the spring loaded cartridge and thereby alternatively extend or retract the implement tip. Having the capability to retract the tip provides the user with the ability to safety and cleanly carry the implement in a pocket or other clothing article. With the tip retracted, ink would not leak onto clothing or cause inadvertent marking of clean surfaces. Moreover, if the implement is configured as a cutting tool, stylus point or other sharp pointed article, the user would now be able to retract the point to have a safe implement for transport storage or other use when exposure of the sharp tip is not required. 
   Other objects, advantages and features of the present invention will be more readily appreciated and understood when considered in conjunction with the following detailed description as drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other aspects of the present invention will now be described with reference to the accompanying drawings, in which: 
       FIG. 1  illustrates a perspective view of an improved hand-held implement, according to the present invention in a fully assembled state with the working tip retracted; 
       FIG. 2  illustrates a perspective view of a the improved hand-held implement according to the present invention in a fully assembled state with the working tip extended; 
       FIG. 3  illustrates a sectional view of the improved hand-held implement with the working tip retracted as shown in  FIG. 1 ; 
       FIG. 4  illustrates a sectional view of the improved hand-held implement with the working tip extended, as shown in  FIG. 2 ; 
       FIG. 5  illustrates an exploded view of the improved hand-held implement shown in  FIG. 3 , further depicting the cartridge, cartridge housing and plunger mechanism; 
       FIG. 6  illustrates an top exploded view of the selection peg, cam way and plunger body of an improved hand-held implement according to the present invention as shown in  FIG. 1 ; 
       FIG. 7  illustrates an perspective exploded view of the selection peg, cam way and plunger body of an improved hand-held implement according to the present invention as shown in  FIG. 1 ; 
       FIG. 8  illustrates an perspective view of the selection peg, cam way and plunger body of an improved hand-held implement in the working tip extended position according to the present invention as shown in  FIGS. 2 and 4 ; 
       FIG. 9  illustrates an perspective view of the selection peg, cam way and plunger body of an improved hand-held implement at a point in the working tip extension stroke position according to the present invention as shown in  FIGS. 3 and 4 ; and 
       FIG. 10  illustrates an perspective view of the selection peg, cam way and plunger body of an improved hand-held implement in the working tip retracted position according to the present invention as shown in  FIGS. 1 and 3 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The purpose of the improved hand-held implement described by the present invention is to present a working tip for the user. In the illustrated embodiments, an ink tip  13  is shown as a working tip incorporated in a pen cartridge. However, the working tip can include any one of a number of devices which require precise manual control. Examples include other writing implements such as pencils and fountain pens, the blade for a cutting implement, a brush for painting, a brush or puff for cosmetic application, a soldering tip or a contacting device such as a computer stylus. 
   In a preferred embodiment, as shown in  FIGS. 1 and 2 , the assembled body  1  of the hand held implement would be constructed of two mating pieces, the first curved body panel  2 , and the second curved body panel  3 . These two pieces would be attached or bonded during the assembly process through common methods, such as snap fitting tabs, sonic welding or adhesive. The assembled body has a first axis A and a second axis B. The second axis B generally perpendicularly intersects the first axis A. Each of these panels would have an inner surface  4  and an outer surface  5 . In use of the assembled body  1  of the implement, the outer surface  5  of the first body panel  2  is engaged by the thumb of a right handed user and the outer surface S of the second body panel  3  is engaged by the middle finger of the user. In this preferred embodiment, the outer surfaces  5  have contours which are smooth and gradual, without sharp edges. Similarly, the two mating body panels  2 ,  3  of the implement are joined smoothly, with rounded edges. These features enhance the level of comfort for the user of the implement. More specifically, as shown in  FIGS. 1 and 2  in the preferred embodiment, the outer surfaces  5  define a smooth ergonomic shape having a forward surface  5   a  and an opposed rearward surface  5   b , and a first side surface  5   c  and an opposed second side surface  5   d  which are contiguous and generally perpendicular to the forward and rearward surfaces  5   a  and  5   b . Part of the four surfaces  5   a ,  5   b ,  5   c , and  5   d  define a bottom portion  5   e  and an opposed and contiguous top portion  5   f . The top portion  5   f  has a generally round bulb shape, as seen in  FIGS. 1 and 2 , and a first convex contour  5   f - 1  smoothly connecting between the forward and rearward surfaces  5   a  and  5   b  such that the top portion  5   f  can be ergonomically fit within the palm of the user. The forward surface  5   a  is contoured such that the user would typically place their index finger thereon substantially parallelly in a direction toward the bottom portion  5   c . For that, the forward surface  5   a  may have a first concave contour  5   a - 1  and further, a contiguous second convex contour  5   a - 2  as shown in  FIG. 1 . Preferably, the first side surface  5   c  is adapted to engage the thumb of a user. The middle finger of the user, on the other hand, rests preferably on the second side surface  5   d , and in addition, may rest the curved forward surface  5   a  upon the distal knuckle area of the middle finger. Furthermore, the rearward surface  5   b  also may have a concave contour  5   b - 1  as shown in  FIG. 1 . This placement of the thumb, index finger and middle finger permits the user to comfortably grip the improved implement, yet hold the implement in a manner quite conducive to accurate and precise positioning of the tip  9  of the implement. Thus, the present invention in use permits the hand of the user to assume a comfortable arched configuration, with the implement being substantially co-planar with the arch defined by the index finger and corresponding portion of the surrounding closed palm of the user. This preferred embodiment of the implement is of a sufficiently small length that it does not extend beyond the hand of the user, but rather fits within the user&#39;s hand. 
   In a particularly preferred embodiment, the width of the implement is thin enough so as to facilitate storage of the implement in a pocket of the user&#39;s clothing. 
   In this preferred embodiment, the surfaces  5 ,  5   a  and  5   b  are oriented so that the implement in use will extend in a direction which is preferably essentially parallel to the user&#39;s index finger, but in any event, a direction which is no further toward the thumb of the user than the index finger. This relationship can also be conceptualized by considering the tip  9  as defining a longitudinal axis, which is preferably substantially parallel to the index finger of the user. 
   Referring to  FIGS. 3 and 4 , a cartridge housing  6  according to the present invention includes one or more coaxial cavities  7 , depicted in  FIG. 5  as a coaxial groove, for retention of the cartridge  8  and tip  9 . In a preferred embodiment, the cartridge housing  6  is cylindrical and elongated. However, the cartridge  8  can be any shape (including square, oblong, conical, etc.) and need not be elongated. A cartridge  8  extends from the cartridge housing  6  and contains the tip  9 . 
   Referring to  FIG. 5 , an exploded view of a hand-held implement according to the present invention is shown. It can be seen that the external shape of the body  1  does not correspond to the external shape of the cartridge housing  6 . Both the body  1  and the cartridge housing  6  may independently have any longitudinal shape. Also, both the body  1  and the cartridge housing  6  may independently have any cross-sectional shape. In a preferred embodiment, the external shape of the hand-held implement is contoured as described above. In a more preferred embodiment, the cross sectional area encompassed by the body  1  is significantly larger than the cross sectional area encompassed by the cartridge housing  6  and the shortest dimension of the body  1  is longer than the shortest dimension of the cartridge housing  6 . The first body panel  2  and the second body panel  3  of the hand-held implement according to the present invention fit together to form the cartridge housing  6 . The cartridge housing  6  may be located anywhere within the body  1  and extend from any facet of the body  1 . A tip  9  extends from the cartridge  8  and the cartridge housing  6 . In a preferred embodiment, the cartridge  8  is a pen cartridge having an ink tip  13 . 
   The coaxial retention stopper  10  of the cartridge  8  is located at a particular distance from the outward end of the cartridge  8  and tip  9 . In the assembled body  1 , the stopper  8 , shown in the preferred embodiment as a circular shoulder, fits into the coaxial cavity  7  to locate and retain the cartridge  8  in the cartridge housing  6 . The predetermined length of the cartridge  8  and location of the stopper  10  with respect thereto defines the desired extension distance of the tip  9 , and in the preferred embodiment, of the ink tip  13 . The stopper  10  and cavity  7  may be of any cross sectional geometry and size appropriate to mate such that they function in unison to locate and retain the cartridge  8 . 
   Referring to  FIG. 5 , a pen cartridge  8  according to the present invention is shown. In a preferred embodiment, the pen cartridge  8  has an ink refill including a rounded cylindrical portion  12 , a spring wrapped ink reservoir  11  and an ink tip  13 . The inner end of the cylindrical portion  12  is slidably engaged with the inclined angled surface  22  of the plunger body  15  for retraction and extension of the ink tip  13 , as described below. 
   In the invention, whatever type of extending tip is incorporated in the cartridge is alternatively extendable and retractable. In the preferred embodiment, the ink tip  13  may be extended from or retracted into the tip  9 . This is accomplished by the use of spring loaded mechanisms. First, the cylindrical portion  12  of the cartridge  8  is spring biased against the cartridge housing  6 . Compression of the cartridge spring  11   a  is accomplished through the controlled length of the cartridge housing  6 , which includes the length from the coaxial cavity to the innermost end  6   a  of the cartridge housing  6 , upon which a shoulder  12   a  of the cylindrical portion  12  is biased. Thus, in a relaxed state whereby the shoulder  12   a  is in contact with the innermost end  6   a , the ink tip  13  is retracted into the cartridge. Again, regardless of the extending tip configuration, it would be retracted in this position. This would be particularly useful toward safety if the tip were a stylus, knife point or other sharp or pointed tip. 
   The preferred embodiment accomplishes the extension of the ink tip  13  by means of a spring biased plunger mechanism, which includes a button,  23 , a spring  14 , a plunger body  15 , a selection peg  16 , a cam way  17 , and a top plate  18 , which is attached to the inner surface  4  of the second body panel  3  by means of multiple attachment points  19 . The button  23  in the preferred embodiment is generally cylindrical with an oblong cross section. Its inboard end includes outward extending tabs  23   a , on two opposing sides to permit the button  23  to extend outward from the assembled body  1  but still be retained within the body by the tabs  23   a . Inside the button  23  resides a button spring  23   b , which exerts an inward axial force upon the flat plate  20  of the plunger body  15 . The plunger body  15  may be configured of any cross sectional shape but is shown in the preferred embodiment as an elongated piece having a square cross section. On its outboard end, the plunger body  15  has a flat plate  20  with a locator pin  21  centered on the outer facing surface of the flat plate  20 . The locator pin  21  locates and guides the force of the button spring  23   b  on the flat plate  20 . The inner end of the plunger body  15  is configured with an inclined angled surface  22  as its end point. The selection pin  16  is generally “U” shaped and the outer leg fits into the slide groove  21  of the plunger body  15 , with the inner leg inserted into the cam way  17  of the plunger body  15 . The selection pin  16  is inserted through the top plate  18  and is held in place by the spring  14 , which warps around the selection pin  16  as well as around the plunger body  15 . As the user depresses the button  23 , the button spring  23   b  applies an axial inward force upon the flat plate  20 . This force displaces the plunger body  15  axially inward, thus moving the cam way  17  inward. The selection pin  16  is not displaced axially, as it is retained through the center hole  18   a  in the top plate  18  as well as the inward radial force upon the selection pin  16  resulting from the wrapped coils of the spring  14 . The outer leg of the selection pin  16  thus is confined to ride in the slide groove  21  of the plunger body  15 . The inner leg of the selection peg  16  follows the elongated chevron shape of the cam way  17 , as the cam way  17  moves laterally with the spring controlled movement of the plunger body  15 . Referring to  FIGS. 8 ,  9  and  10 , upon first depression of the button  23 , the selection peg slides down the front side leg of the cam way  17  and rests in the outer “V” portion of the cam way  17  to extend the ink tip  13 . A second pressing of the button causes the selection pin  16  to follow the rear profile of the cam way  17 , and the selection pin  16  comes to rest in the inner “V” portion of the chevron cam way  17 , whereupon the ink tip  13  is fully retracted. 
   This movement of the cam way  17  and plunger body  15  is locked in the above described extension and retraction positions by the location of the selection pin  16  in either the outer “V” portion of the cam way  17  (See  FIG. 8 ) or the inner “V” portion of the cam way  17  (See  FIG. 10 ), respectively. The lateral movement of the plunger as described above correspondingly moves the end point of the inclined angled surface  22 . As this inclined angled surface  22  moves inward due to the axial force of the button spring  23   b  as applied by pressing the button  23 , it is slidably engaged with the inner end of the cylindrical portion  12  of the cartridge  8 . Although the relative geometry may vary based upon the lengths, sizes and resultant angles, in the preferred embodiment, the plunger body is coplaner with but oriented at approximately 90 degrees with respect to the cartridge  8  and cartridge housing  6 . Accordingly, the angle of the inclined angled surface  22 , is approximately 45 degrees and slopes rearward, such that its leading edge is lower than its trailing edge. Thus, as the plunger body  15  advances laterally inward, the sliding engagement of the inclined angled surface  22  with the cylindrical portion  12  of the cartridge  8  results in an axial force pushing outward upon the cylindrical portion  12  of the cartridge  8 , thereby extending the ink tip  13 , which is linearly connected to the cylindrical portion  12  of the cartridge  8 . 
   The improved hand-held implement can be of any suitable dimensions consistent with the above relationships. The implement can be scaled up or down so as to provide different implements of different sizes which can thereby accommodate users with different size hands. The implement of the present invention can be made of any material suitable for the intended purpose of the implement. Examples include various polymeric materials, metal, wood and glass. It should also be noted that the outer surfaces  5 , of the body  1  of the device provide a relatively smooth flat surface which is well-suited for application of art work, logos and advertising. 
   While there is shown and described herein certain specific structures embodying this invention for the purpose of clarity of understanding, the same is to be considered as illustrative in character, it being understood that only preferred embodiments have been shown and described. It will be manifest to those skilled in the art that certain changes, various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated in the scope of the claims.