Patent Abstract:
A multi-purpose work knife includes a universal elongate ergonomically-shaped handle (UEH) which defines an axis and includes a blade having an UEH blade axis. Within the handle portion, a channel member is received in a forwardly extending cavity and movably receives a cutting blade carrier for axial movement relative to the handle portion. A selectable non-universal portion (SNP) is secured at one end to said UEH at a plane of continuity of curvature thru which the UEH axis passes. The SNP holds non-standard blade at an angular offset relative to the UEH axis. A cutting edge of the SNP blades defines a virtual angle which intersects the UEH axis within a range of 20 to 30 degrees.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to work knives and, more particularly, work knives having multiple purposes including, without limitation, cutting, scraping, grouting, and plastering. The knife is further adapted to the particular needs of left handed workers as well as environments in which it would be advantageous to employ one&#39;s left hand for a given purpose. 
     2. Prior Art 
     The Field of utility knives includes many examples of previous attempts, extending over many years, all of which are directed to the provision of a utility knife which satisfies one or more of the historic concerns associated therewith. These concerns include those of cost, safety, durability, and ergonomics, that is, compatibility with the human hand. A further need in the prior art is that for the storage of spare knife blades within the utility knife itself. A further need, however rarely addressed in the prior art, is that of a utility knife usable for many purposes and, as well, adaptable for use by workers which are both left and right handed. 
     The traditional trapezoidal-shaped, double-ended utility knife blade has been well known for over sixty years. See, for example, U.S. Pat. No. 2,145,985 (1939) to Krajecik. More recent efforts to improve upon the classical utility knife are reflected in U.S. Pat. No. 5,012,581 (1991) to Fletcher; U.S. Pat. No. 5,490,331 (1996) to Gold; U.S. Pat. No. 5,613,300 (1999) to Schmidt; U.S. Pat. No. 5,623,737 (1997) to Moyer; and U.S. Pat. No. 6,058,607 (2000) to Gringer. 
     None of this art, nor other art known to the within inventor, discloses a utility knife having a handle surface which is particularly proportioned to the human hand and the gripping function associated therewith when such a knife is held. Further, the prior art does not provide for a utility knife having integrated therewith a non-utility knife portion capable of both cutting and non-cutting functions. Also, the prior art does not provide for a multi-purpose utility knife having a portion thereof which may be selectably changed on the basis of whether or not the user is left or right handed or if a given work assignment, project or problem within a work environment is one in which a “left” versus a “right” handed tool would be more advantageous for such a particular purpose. 
     The present invention addresses, in an integrated fashion, all of the above long felt needs that have existed in the art of utility knives. 
     SUMMARY OF THE INVENTION 
     A multi-purpose work knife, comprises a universal elongate handle (“UEH”) extending generally upon a UEH axis, said handle having a compound, convex curvature and an assembly within, at a top surface of a first end of said UEH, for holding a UEH utility knife blade in a selectable longitudinal position defined by a cutting edge of said UEH blade, said UEH also defining substantially oval radial cross-sections between said blade holding assembly and a second end thereof, said cross-sections defining slightly smaller radii at about a center region of said UEH, said second end comprising complemental securement means; and a selectable non-universal portion (“SNP”) having a first end and a second end, said second end comprising means for selectable complemental securement to said UEH complemental securement means, said second end of said SNP having a like radius and curvature to said second end of said UEH at opposing surfaces thereof, said UEH axis passing through said complemental securement means of said surfaces of said second ends of said UEH and SNP respectively, said SNP further comprising, at a first end and top surface thereof, an assembly for selectably holding a knife blade having a cutting edge projecting away from said first end of said SNP, in which said cutting edge of said SNP blade defines an angle which intersects said axis of the UEH blade, at a virtual extension external to said work knife, in a range of about 20 to about 40 degrees. Said SNP may selectably take several forms including a left angled axis relative to the axis of the UEH, a right angled axis relative thereto, and an axis substantially co-linear with said UEH axis. 
     It is an object of the invention to provide a multi-purpose work knife having a universal portion corresponding to the classical function of a utility knife and having a non-common portion which provides for adaptability of the knife to the needs of left versus right handed persons and, as well, affords numerous additional cutting and non-cutting functions. 
     It is another object to provide a multi-purpose work knife of the above type having a surface curvature and geometry particularly adapted for the requirements of the human hand during the gripping of a utility knife. 
     It is thereby a further object of the invention to provide an improved multi-purpose knife which is usable with equal facility by both left-handed and right-handed persons. 
     It is a still further object to provide a work knife which, alternatively, may be employed in numerous non-utility cutting and non-cutting applications. 
     The above and yet other objects and advantages of the present invention will become apparent from the hereinafter set forth Brief Description of the Drawings, Detailed Description of the invention and claims appended herewith. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the inventive multi-function work knife. 
     FIG. 2 is a top perspective view of the knife of FIG.  1 . 
     FIG. 3 is a bottom elevational view thereof. 
     FIG. 4 is a side elevational view of the invention showing the difference in angulation of the respective planes of the utility knife portion of a tool versus the non-utility knife portion thereof. 
     FIG. 5 is a top plan exploded view of the multi-purpose work knife. 
     FIG. 5A is a front plan view of the non-universal portion of the work knife showing the blade holding means associated therewith. 
     FIG. 6 is a bottom view of the inventive knife particularly showing the relationship between the various virtual axes which define the invention. 
     FIG. 7 is a front elevational view of the universal handle portion of work knife. 
     FIG. 8 is a front elevational view of the selectable non-universal portion of the inventive multi-purpose work knife. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to views of FIGS. 1 to  6 , the present inventive multipurpose work knife  10  may be seen to include a universal elongate handle part  12  (hereinafter the “universal handle”) or “UEH” the elongation of which extends generally along an “UEH” axis  14 . Said universal handle, as may be noted with reference to FIGS. 1 and 4, defines a compound convex generally cylindrical surface in which a transverse cross-section thereof defines slightly smaller radii at about a center region  16  thereof. 
     With further reference to FIGS. 1 to  6 , it is noted that the universal handle  12  includes a first end  18  and a second end  20 . Upon a top surface of said universal handle is provided a knife-blade holding assembly  22  which includes several constituent elements, these including a thumb recess  24 , a blade control knob  26  and a blade channel  28 . A utility knife blade  30  and its cutting edge  32  are held within channel  28  and adjustably positioned by the function of knob  26 . Therein, blade  30  may, during periods of non-use, be held in a fully withdrawn position as is shown in FIGS. 2 and 3. Therein, said utility knife blade  30  will reside slightly inwardly of distal edge  34  of first end  18  of universal handle  12 . Said edge defines an axis  69  (see FIG. 2) which exhibits an angle B of about 20 degrees relative to said UEH axis  14 . When knob  26  is employed to facilitate the fullest possible extension of utility knife blade  30 , cutting edge  32  thereof and its associated point  36  will project well beyond distal edge  34  end of first end  18  of universal handle  12  of the work knife  10 . It is to be appreciated that the views of FIGS. 1 and 6 show the inventive knife with UEH blade  30  inserted within holding assembly  22 , while that of FIGS. 2,  3 , and  5  show the work knife and holding means  22  without blade  30 . It is further noted that said cutting edge  32  defines an axis  37  which exhibits an angle G relative to distal edge  34 , and an angle I relative to UEH axis  14 . 
     A variety of strategies may be employed to secure blade  30  within holding assembly  22 . One such strategy is shown in the views of FIG.  5 . Therein, channel  28  is provided with a linear plurality of pins  38  which are placed and dimensioned for complemental engagement of apertures  40  within the blade  30 . This approach enables a user to select a desired degree of extension of blade  30  from distal edge  34  of first end  18  of the universal handle  12 . Also shown is knob  26  of holding assembly  22  having an axle (not shown) which threadly engages a vertical bore  42  within said channel  28  of the holding assembly  22 . It should be appreciated that holding assembly  22  further includes a hold-down plate  44  which is also secured by knob  26 , this to maintain stability of blade  30  within the assembly  22  and to contribute to the safety and aesthetics associated with the entire structure. 
     As may be noted with reference to the perspective views of FIGS. 1,  7 , and  8 , radial cross-sections of universal handle  12  defines substantially oval cross-sections between said thumb recess  24  of the holding assembly  22  and second end  20  of the universal handle  12 . Included within said second end  20  of universal handle  12  is female means  45  or complemental securement means, later described below. 
     With reference to the views of FIGS. 1 through 6, the inventive handheld utility knife  10  may be seen to further include a selectable non-universal portion (“SNP”)  46  having a first end  48  and a second end  50  having a male means  51  is proportioned for complemental engagement with female means  45  of second end  20  of said universal handle  12 . See FIG.  5 . It is further noted that said UEH axis  14  (see FIG. 2) of said universal handle extends through interface  53  which exists at a complemental joinder between said first ends  20  and  50  and into said non-universal portion  46  to a thumb recess  50  which is associated with a blade holding assembly  52  of said non-universal portion  56 , having an axis  54 . See FIGS. 2 and 6. It is to be appreciated that, in a preferred embodiment, the inventive utility knife will be sold in a kit which is provided with both a left and a right hand embodiment of said non-universal portion  46 , this to accommodate the needs of respective right and left handed workers and, as well, to accommodate particular work or cutting environments in which the use of either a left or right handed non-universal portion  46  would be particularly advantageous to the worker without regard to whether the worker is right or left handed. That is, there exist numerous work environments and work spaces in which the desired angle of cut for the work project, or preferred leverage of the worker, is more readily achieved with a non-universal portion directed either to the left or to the right of said UEH axis  14  of universal handle  12 . It is, thereby, to be understood that while the within drawings, and associated description, describe a selectable non-universal portion  46  which, in top view, projects to the left relative to said UEH axis  14 , the instant invention is equally applicable to the use of a selectable non-universal portion which is substantially a mirror image of the non-universal portion  46  shown in the figures and which, thereby, would project to the right relative to said axis  14 . An angulation A of this projection is defined by said axis  54  (see FIG. 2) of non-universal portion  46  relative to UEH axis  14 . This angulation falls in a range of about 110 to about 140 degrees. 
     Said holding assembly includes a substantially triangular recess  56  (see FIGS. 2 and 5) as well as a securement knob  58 . 
     As may be noted in FIGS. 1,  5 ,  5 A, and  6 , holding assembly  52  is adapted for the securement of a substantially triangular blade  60  or a blade having the general geometry of a parallelogram, and having a cutting edge  61  substantially parallel to an edge of said SNP first end. 
     It is, however, to be noted that the holding assembly  52  of non-universal portion  56  is adapted to secure transverse, as opposed to longitudinal, movement of blade  60 . This may be more fully appreciated with reference to the view of FIG. 5A in which there is shown a plurality of projections  62  from triangular recess  56  of non-universal portion  46 . Provided on blade  60  is a corresponding plurality of apertures  64  to permit the positioning of blade  60  upon the projections  62  of channel  56 . As in the case of first holding assembly  22 , knob  58  includes an axle, not shown, which threadly engages a vertical bore  66  (see FIG. 5) to selectably effect the positioning and securement of a hold down piece  68  (see FIGS. 4 and 8) upon blade  60 . 
     One distinguishing parameter of the present invention is that an axis  67  of channel  28  of first holding assembly  22  will, at a point of intersection with UEH axis  14  and, at the axis of rotation of knob  26 , define an acute angle B in a range of 10 to 25 degrees. (See FIG.  2 ). It is further noted that, in a preferred embodiment, distal edge  34  of first end  18  of universal handle  12  defines an axis  69  which intersects said UEH axis  14  at an angle C which is in a range of 40 to 50 degrees, and which is substantially parallel with said axis  54  of said SNP blading holding assembly  52 . See FIGS. 2 and 6. 
     Generally, first end  48  of non-universal portion  46  is linear and defines an axis  70  which, while substantially normal to said axis  54 , intersects said UEH axis  14  (to the left of non-universal portion  46 ) at a virtual angle D which is in a range of 20 to 40 degrees. This angle will be substantially the same in either the left or right-handed embodiment of the non-universal portion. In the left handed embodiment thereof, i.e., in the embodiment shown in figures, said axis  69 , corresponding to a virtual extension of said edge  34  of first end  18  of universal portion  12 , will intersect with said axis  70  at an angle E which is typically in a range of 80 to 120 degrees. 
     It has also been found that such an angulation H of axis  70  of the edge  61  of SNP blade  60  relative to axis  37  of edge  32  of UEH blade  30  produces an advantageous leverage to a user of the present work knife, if it is in a range of 20 to 40 degrees. It is to be appreciated that the flared structure of triangular blade  60  of the non-universal portion will have cutting, scraping, grouting, plastering and other applications which will enhance the generalized utility of the present invention. 
     The utility of the invention is also furthered by triangular side surfaces  72 ,  74  and  75  (see FIGS. 4 to  8 ) of the handles as well as the relative positioning of plane  76  of utility knife blade  30  relative to plane  78  which is defined by triangular blade  60  (see FIG.  4 ). Therein, it has been found that an obtuse angle F, formed at an intersection of said planes in a range of 160 to 170 degrees, is most useful. That is, the advantages of the invention are yet further enhanced by such relative angulation F of planes  76  and  78  relative to each other. 
     It is to be appreciated that said SNP may selectably take several forms including a left angled axis relative to the axis of the UEH, a right angled axis relative thereto, and an axis substantially co-linear with said UEH axis. 
     While there has been shown and described the preferred embodiment of the instant invention, it is to be appreciated that the invention may be embodied otherwise than is herein specifically shown and described and that, within said embodiment, certain changes may be made in the form and arrangement of the parts without departing from the underlying ideas or principles of this invention as set forth in the claims appended herewith.

Technology Classification (CPC): 1