Abstract:
A cutting die head assembly for nibbler tools which enables the die head to be independently rotatably manipulated by the user&#39;s hand independent of its axial connection with the die body to provide for angular and/or circular cuts in areas of limited space use and thus avoiding the necessity of moving the nibbler body and attached drill in a similar path.

Description:
Applicant claims the benefit of U.S. Provisional Patent Application Ser. No. 60/440,930 filed Jan. 17, 2003. 

   BACKGROUND OF THE INVENTION  
   This invention relates to nibbling tools and more specifically to a nibbling tool incorporating a unique die head structure that enables hand direction of the cutting path afforded thereby as opposed to a path determined solely by the directional path of the overall tool including the rotary drill. 
   Nibbling tools have been available in various forms for many years and include those set forth in UK Patent No. 1,485,795 published Sep. 14, 1977; U.S. Pat. No. 4,489,492 issued Dec. 25, 1984; U.S. Pat. No. 4,748,744 issued Jun. 7, 1988 and U.S. Pat. No. 4,158,913 issued Jun. 26, 1979. 
   All of the above-noted patents disclose a nibbler tool that includes a single die cutting head and a punch or blade that reciprocates with respect to the die. A source of rotary motion such as a rotary drill is attached to a shaft extending from the rear of the nibbler tool and connected thereto. A handle extends outwardly from the body of the tool in order for the operator to manipulate the tool by grasping both the handle as well as the drill body. In some advanced nibbler tools, a second die head is provided. In such double-ended tools depending upon which die head is utilized for cutting operation at any one time, the other die head is provided with a removable grip or handle that fits firmly over the outside surfaces thereof. 
   The die head has an entry area or slot for receipt of sheet material such as a thin sheet metal and is provided with a cutting surface that cooperates with the punch or blade. During operation, the punch or blade reciprocates in a linear motion and cooperates with the die cutting surface to bite or nibble a small crescent-shaped piece of material from the sheet with each punch stroke. As the operator&#39;s hands guide the tool, the nibbler tool cuts a slot in the direction of motion, that is, the movement of the tool including the drill determines the cutting path. Obviously if it is desired to cut angular or curved slots especially in small spaces, it is extremely difficult to manipulate the tool in the desired cutting path; and, accordingly, this is a drawback of such tools. 
   Accordingly, it would be highly desirable to be able to provide nibbler tools of the above type with a mechanism that would enable them to be more easily utilized in tight quarters and provide for the movement of the cutting die head independent of the remainder of the tool and the power drill attached thereto. Accordingly, it is the object of the present invention to provide a cutting tool structure having a cutting die head that can be rotated independently of the tool body via one&#39;s fingers by providing forward and/or angular motion to the tool by grasping the drill in the other hand. These and other objects of the present invention are accomplished by mounting the die head on the body of the nibbler tool such that it is restrained from axial movement therewith but is free to rotate as determined by the manipulation of the worker&#39;s hand in maneuvering the direction of the cutting path. Such independent die cutting head movement enables angular and/or circular cutting paths to be achieved without the attendant movement of the nibbler tool body and attached drill in the same angular and/or circular movement. In this way, angular and/or circular cutting paths can be achieved while utilizing the nibbler tool in restricted areas where similar movement of the tool and attached drill cannot be accomplished due to potential contact with other structures in the work area. 
   Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings. 

   
     DESCRIPTION OF THE DRAWINGS  
     In the drawings which illustrate the best mode presently contemplated for carrying out the present invention: 
       FIG. 1  shows a cross-sectional view of a prior art nibbler tool; 
       FIG. 2  shows a cross-sectional view of a nibbler tool incorporating the present invention; 
       FIG. 3  is an elevational view of one die of the nibbler tool of  FIG. 2  showing the manner in which such is attached to the nibbler body to achieve rotational movement with respect thereto; 
       FIG. 4  is partial sectional view through  FIG. 2  to show how the axially limiting setscrew extends into a circular groove in the die head body which restrains such from axial movement but does not fixedly position such with respect thereto; 
       FIG. 5  is a side elevational view of one end of the body showing the circular motion which the die head is mounted with respect thereof; 
       FIG. 6  is a schematic view showing the manner in which the die head may be manipulated by the user in a tight position such that a circular cutting path is achieved while providing substantially only forward and rearward motion to the tool and connected drill; and 
       FIG. 7  is a perspective view showing the manner in which the die head is hand manipulated to control the cutting path. 
   

   DETAILED DESCRIPTION OF THE INVENTION  
   Turning now to the drawings and particularly to  FIG. 1 , the nibbler  10  shown therein includes a body  12  of generally cylindrical shape and including an open bore  14  at the top  16  thereof which part forms an internal cavity  18 . A drive mechanism  20  is located in the cavity and is utilized to transfer rotary movement from a drive shaft  22  to reciprocating longitudinal movement of a blade connector. The shaft extends through the base  24  of the body  12  and connected to the drive mechanism at one end thereof and a source of rotary motion such as a rotary drill (not shown) at the other end thereof. The drive mechanism is, in turn, connected to a blade location block  25  which includes a longitudinally extending body  26  having a longitudinal bore  28  therethrough adapted to receive and removably connect the nibbler blade  30  thereto. The drive mechanism may be of any known appropriate structure and of itself forms no part of the present invention. 
   A setscrew  32  is adapted to be threaded into an upper bore  34  in the blade location block and is provided with a conically-shaped forward end  36  that extends into a depression  38  centrally formed in the blade  30 . A lock  40  in the form of a nut having an internal threaded bore that engages both the setscrew and the top surface of the blade block is provided to assure continual fixed engagement of the blade location block to the blade. End cap  42  is provided to close the opening of the body  12 . Normally, a spring clip (not shown) is utilized to hold the end cap in position, but other means can be utilized. 
   A pair of aligned bores  48  extend through opposed sides of the body  12  in alignment with the blade location block bore but each of far greater diameter to respectively receive an inner forward cylindrically-shaped end  50  of each of the dies  52 . The dies include a central bore  54  to receive the blade—each bore being aligned with each other such that the blade may reciprocate upon drive shaft movement longitudinally within the compositely formed structure and operate to cut sheet material as it is fed into the receiving slot  58  of each die by the forward movement of the device vis-a-vis the sheet as is known in the art. 
   It will be apparent from the above description of the prior art device that each die is fixedly connected to the body  12 , such connection being made via a setscrew  60  downwardly extending through the secondary bore  62  provided in the top surface of the body and extending downwardly and opening at the bores  48  if two dies are mounted in the body. Of course if only one die is mounted, only one above-described connecting mechanism at one side of the body is needed, however, a tight fitting sleeve may be placed over the second die when utilized and such sleeve can serve as a guide or grasping surface for manipulating the tool or the operator can simply grasp the body of the rotary drill connected to shaft  22 . By tightening the setscrews  60  into contact with the outer surface of the cylindrically-shaped end  50  thereof, the die  52  is fixedly attached to the body  12 ; and, accordingly, the entry slot  58  into which the sheet material to be cut is received is positioned in a single direction. Thus if the direction of the slot to be cut in the sheet material must be changed, then the body as well as the attached rotary drill has to be moved in a similar direction. 
   Turning now to  FIG. 2 , it will be apparent that the immediately above aforementioned restriction to prior art tools of this type is eliminated by providing a downwardly extending circular groove  66  at the cylindrically-shaped end  50  of each of the dies  52 . In this way, the end of the setscrew  60  can be downwardly screwed so as to extend into such groove  66  but not touch contact the bottom base thereof to restrain the die head  52  from axial movement with respect to the body  12  but not limit the ability of the die head  52  to rotate with respect thereto. This assumes the setscrew  60  is of an axial extent slightly less than that of the groove, which is the case. When axial movement is attempted in either direction, the opposing wall areas  68  of the groove contact the opposed wall areas  70  of the setscrew restraining such axial movement. However, the ability of the die head to rotate as particularly shown in  FIG. 6  is not restrained. 
   An intermediate section of the die head  52  is provided with a knurled surface  72  to aid the operator in manipulating such die. Thus as shown in  FIG. 6 , while moving the drill and body in an upward path, the die head can be simultaneously turned by the operator&#39;s hand in contact with die head  52  to present its receiving slot  58  in an outward angular position and then twist it again in a an inward angular direction and thence the reverse of such movements while the drill and body are moved downwardly to form a circular cut  76  as shown. During such tool manipulation, the tool may be supported by the operator&#39;s hands, one hand on the drill or housing and the other hand on the die cutting head. The drill may be in a fixed on position or controlled by the operator. Obviously, other types of angular and/or circular curved cuts may be accomplished by such technique. Also in those instances when the tool is not being utilized in close or small spatial environments and the operator otherwise chooses not to manipulate the cutting path by the movement of the die head relative to its connecting body, then the setscrew  60  can simply be screwed downward until its bottom surface  63  contacts the upper surface  64  of the channel  64  and thus provides a fixed connection therewith similar to such fixed connection in prior art devices. 
   While there is shown and described herein certain specific structure embodying this invention, it will be manifest to those skilled in the art that 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 by the scope of the appended claims.