Abstract:
An apparatus for clipping a protrusion of material is provided. The protrusion may, for example, be a bolt head, a nut, a rivet, a weld bead, or a temporary assembly alignment tab protruding from a substrate surface of assembled components. The apparatus typically includes a cleaver having a cleaving edge and a cutting blade having a cutting edge. Generally, a mounting structure configured to confine the cleaver and the cutting blade and permit a range of relative movement between the cleaving edge and the cutting edge is provided. Also typically included is a power device coupled to the cutting blade. The power device is configured to move the cutting edge toward the cleaving edge. In some embodiments the power device is activated by a momentary switch. A retraction device is also generally provided, where the retraction device is configured to move the cutting edge away from the cleaving edge.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a Continuation Application of and claims priority from U.S. patent application Ser. No. 11/612,852 filed Dec. 19, 2006, entitled: “Powered Protrusion Cutter,”—now U.S. Pat. No. 7,673,392. 
    
    
     GOVERNMENT RIGHTS 
     The U.S. Government has rights to this invention pursuant to contract number DE-AC05-00OR22800 between the U.S. Department of Energy and BWXT Y-12, L.L.C. 
    
    
     FIELD 
     This invention relates to the field of power tools. More particularly, this invention relates to power tools for cutting material protruding from a surface, such as a bolt head, rivet head, or nut. 
     BACKGROUND 
     In many manufacturing and construction activities it is frequently necessary to remove a protrusion of material from a component or from a substrate surface. Examples of such removal operations include clipping the head off a bolt and the removal of a bolt head, a nut, a rivet, a weld bead, or a temporary assembly alignment tab from a substrate surface of assembled components. These operations may be required during normal assembly, during demolition of equipment or facilities, or during product repair or manufacturing rework activities. Various tools such as bolt cutters, chisels, drills, grinders, and acetylene torches are sometimes used for removal of a protrusion of material from a substrate surface. The application of power tools often results in one or more undesirable process characteristics, such as damaging the substrate surface due to excessive temperature or physical marring, or failing to remove all of the protrusion of material due to a mismatch between the cutting edge of the removal tool and the substrate surface. In addition, many power tools require more time to effect the removal of a protrusion than is economically desirable. Manually-powered tools not only suffer from some of the same undesirable characteristics of powered tools, they also are generally limited to removal of small quantities of small protrusions because of the physical strength and endurance limits of an operator. What are needed therefore are improved tools for economically, quickly and easily removing a protrusion of material from a component or from a substrate surface. 
     SUMMARY 
     The present invention provides an apparatus for clipping a protrusion of material. The apparatus includes a shearing block that has a shearing edge for engaging a first portion of the protrusion of material and a cutting blade that has a cutting edge for clipping the protrusion of material as the cutting blade engages an opposing portion of the protrusion of material. In this embodiment a mounting structure is configured to confine the shearing block and the cutting blade and to permit a range of relative movement between the shearing edge and the cutting edge where the range of relative movement is within a first substantially flat plane defined by the shearing edge and the cutting edge through the range of relative movement. An actuator is configured to move the cutting edge toward the shearing edge in the first substantially flat plane and to move the cutting edge away from the shearing edge. 
     Another embodiment of an apparatus for clipping a protrusion of material is provided. In this embodiment the apparatus includes a shearing block that has a shearing edge for engaging a first portion of the protrusion of material and a cutting blade that has a cutting edge for clipping the protrusion of material as the cutting blade engages an opposing portion of the protrusion of material. The cutting edge and the shearing edge have a substantially parallel orientation. There is a parallel guide that is configured to confine the shearing block and the cutting blade and to permit a range of relative movement between the shearing edge and the cutting edge wherein the parallel orientation of the shearing edge and the cutting edge is maintained through the range of relative movement. An actuator is configured to move the cutting edge toward the shearing edge in the first substantially flat plane and to move the cutting edge away from the shearing edge. 
     A further embodiment of an apparatus for clipping a protrusion of material includes a shearing block having a shearing edge for engaging a first portion of the protrusion of material and a cutting blade having a cutting edge for clipping the protrusion of material as the cutting blade engages an opposing portion of the protrusion of material. There is a mounting structure that is configured to confine the shearing block and the cutting blade and to permit a range of relative movement between the shearing edge and the cutting edge. An actuator is configured to move the cutting edge toward the shearing edge by actuation of a momentary switch that is proximate to the apparatus. The actuator is further configured to move the cutting edge away from the shearing edge. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various advantages are apparent by reference to the detailed description in conjunction with the figures, wherein elements are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein: 
         FIG. 1A  is a perspective illustration of a receiving block. 
         FIG. 1B  is a perspective illustration of a cleaver. 
         FIG. 1C  is a perspective illustration of a cutting blade. 
         FIG. 2  is a perspective illustration of a mounting plate for holding cutting blades. 
         FIG. 3  is a perspective illustration of the cutting blade of  FIG. 1C  and the cleaver of  FIG. 1B  assembled with the mounting plate of  FIG. 2 . 
         FIG. 4  is a perspective illustration of a retaining plate assembly, adding a top plate to the elements depicted in  FIG. 3 . 
         FIG. 5  is a perspective illustration of a power device and a retraction device assembled with the elements depicted in  FIG. 4 . 
         FIG. 6  is a perspective illustration of an apparatus for clipping a protrusion of material. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part hereof, and within which are shown by way of illustration specific embodiments by which an apparatus for clipping a protrusion of material may be practiced. It is to be understood that other embodiments may be utilized, and that structural changes may be made and processes may vary in other embodiments. 
       FIG. 1A  illustrates a receiving block  2 . The receiving block  2  may be used to brace a protrusion of material so that it may be cut off. The receiving block  2  has a receiving surface  4  and a receiving edge  6 . The receiving edge  6  is characterized by being on the geometric plane where the protrusion of material is cut off. The receiving edge  6  is further characterized by being configured for being positioned on the surface of a substrate bearing a protrusion. 
       FIG. 1B  illustrates a cleaver  10 . The cleaver  10  may be used instead of the receiving block  2  of  FIG. 1A  to facilitate the clipping of a protrusion of material. The receiving block  2  of  FIG. 1A  and the cleaver  10  of  FIG. 1B  are examples of “shearing blocks.” The cleaver  10  has a cleaving edge  12  and a first rail  14  and a second rail  16 . The cleaving edge  12  is characterized by being on the geometric plane where the protrusion of material is cut off. The cleaving edge  12  is further characterized by being configured for being positioned on the surface of a substrate bearing a protrusion. The receiving edge  6  of  FIG. 1A  and the cleaving edge  12  of  FIG. 1B  are examples of “shearing edges.” The cleaver  10  of  FIG. 1B  is a preferred configuration of a shearing block because its cleaving edge  12  assists in clipping the protrusion of material. The cleaver  10  will be used hereinafter to illustrate the usage of a shearing block. 
       FIG. 1C  illustrates a cutting blade  30 . The cutting blade  30  may be used to cut off a protrusion of material. Cutting blade  30  includes a cutting edge  32  and a third rail  34  and a fourth rail  36 . The cutting edge  32  is characterized by being on the geometric plane where the protrusion of material is cut off. The cutting edge  32  is further characterized by being configured for being positioned on the surface of a substrate bearing the protrusion to be cut off. The cutting blade  30  also includes a tang  38  and the tang  38  includes a post mounting hole  40 . 
       FIG. 2  illustrates a mounting plate  50  for holding shearing blocks and cutting blades. The mounting plate  50  has a sole  52  with a sole under-surface  54 . The sole  52  includes a first track  56  and a second track  58 . An opening  60  is provided between the first track  56  and the second track  58 . The mounting plate  50  further includes a first side member  62 , a second side member  64 , and an end block  66 . The mounting plate  50  also has a tang slot  68  and ten threaded plate holes  70  and two housing mount holes  72 . 
       FIG. 3  illustrates a blade assembly  80 . Blade assembly  80  includes the cleaver  10 , the cutting blade  30  and the mounting plate  50  (from  FIGS. 1B ,  1 C, and  2  respectively). The end block  66  and portions of the first side member  62  and the second side member  64  and the sole  52  ( FIG. 2 ) form a “base,” and the cleaver  10  is held by the base in a configuration that is substantially stationary relative to the mounting plate  50 , by a suitable fastening mechanism. In some embodiments the end block  66  may serve the function of a shearing block, obviating the need for a removable shearing block such as the cleaver  10 . However, the use of a removable shearing block, such as the cleaver  10 , is preferred because it may be more easily replaced when the shearing edge (cleaving edge  12 ) becomes worn with usage. 
     The cutting blade  30  is disposed on the first track  56  and the second track  58  of the mounting plate  50 . The first track  56  and the second track  58  are an example of a “track system.” The third rail  34  and the fourth rail  36  of the cutting blade  30  depicted in  FIG. 1C  are an example of a “rail system.” The track system formed by the first track  56  and the second track  58  is configured to slidably support the rail system formed by third rail  34  and fourth rail  36 . “Slidably support” means that the cutting blade  30  may slide toward the cleaver  10  in direction  82 , and furthermore, after the cutting blade  30  has slid toward the cleaver  10  (from its position depicted in  FIG. 3 ), the cutting blade  30  may slide away from the cleaver  10  in direction  84 . 
     The previously-described base, (i.e., the end block  66  and portions of the first side member  62  and the second side member  64  and the sole  52 ) “confines” the cleaver  10 . The first track  56  and the second track  58  “confine” the cutting blade  30 . A cutting blade may be “confined” by being held substantially stationary relative to a structure (as the cleaver  10  is held by the base), or a cutting blade may be confined by being restricted to a range of motion by the mounting structure (as the cutting blade is held by the track system). A structure that confines one or more cutting blades or confines one or more shearing blocks is referred to herein as a “mounting structure.” 
     The cleaving edge  12  and the cutting edge  32 , as illustrated in  FIG. 3 , have a substantially parallel orientation to each other. When the cutting edge  32  slides toward or away from the cleaving edge  12 , the substantially parallel orientation between the cleaving edge  12  and the cutting edge  32  is maintained. In view of the parallel orientation of the cleaving edge  12  and the cutting edge  32  that is maintained by the first track  56  and the second track  58 , that track system is an example of a “parallel guide.” A parallel guide is an example of a mounting structure. 
     In the embodiment of  FIG. 3  the cleaver  10  and the cutting blade  30  are detachably held by the parallel guide (i.e., detachably held by the first track  56  and the second track  58 ). “Detachably held” means that the cleaver  10  and the cutting blade  30  are separable from the parallel guide without damage to any of the components. A configuration where cutting blades are detachably held is advantageous because the blades may be removed for sharpening or replacement when needed. 
     When the cutting edge  32  slides toward or away from the cleaving edge  12  the relative movement between cleaving edge  12  and cutting edge  32  is within a first substantially flat plane that, in this embodiment, is substantially co-planar with the sole under-surface  54  of the mounting plate  50 . The parallel guide established by the track system formed by the first track  56  and the second track  58  forms a second substantially flat plane, and the first substantially flat plane is offset from the second substantially flat plane by distance  74 . This second substantially flat plane is preferably above the sole under-surface  54  of the mounting plate  50 . This second substantially flat plane is below a third substantially flat plane defined by an upper surface  76  of the mounting plate  50 . In the embodiment of  FIG. 3 , when the sole under-surface  54  of the mounting plate  50  is placed on a substrate surface with a protrusion of material (e.g., a bolt head) projecting into the opening  60 , the offset between the first substantially flat plane and the second substantially flat plane permits the cleaving edge  12  and the cutting edge  32  to shear the protrusion of material substantially flush with the substrate surface. 
     In the embodiment of  FIG. 3  the range of relative movement between the cleaving edge  12  and the cutting edge cutting edge  32  is achieved by movement relative to the base of only the cutting edge  32 . In alternative embodiments, a range of relative movement between a cleaving edge and a cutting edge may be achieved by movement of both the cleaving edge and a cutting edge relative to a base. 
       FIG. 4  illustrates a retaining plate assembly  90 . The retaining plate assembly includes a top plate  92  that is disposed atop the components depicted in  FIG. 3 . In this embodiment top plate  92  has a pattern of ten plate holes  94  that match the pattern of the ten threaded plate holes  70  of  FIG. 2 , and the top plate  92  has four housing mount holes  96 . In some embodiments the mounting plate  50  ( FIG. 2 ) and the mounting plate  90  ( FIG. 3 ) may have more or less than ten threaded plate holes  70  and ten plate holes  94  (respectively), but the number of the plate holes  94  typically matches the number and pattern of the threaded plate holes  70 . Top plate  92  is configured to cooperate with the parallel guide formed by the first track  56  and the second track  58  ( FIGS. 2 and 3 ) that is configured to further confine the cleaver  10  and the cutting blade  30  and permit relative movement between the cleaver  10  and the cutting blade  30 . 
       FIG. 5  illustrates further components assembled with the components of  FIG. 4 . A hydraulic ram  100  is coupled to the cutting blade  30  by the tang  38 . The hydraulic ram  100  is an example of a power device. Furthermore, the hydraulic ram  100  in the embodiment of  FIG. 5  is an example of a power device that when activated is configured to move the cutting edge  32  of the cutting blade  30  toward the cleaving edge  12  of the cleaver  10  in the previously-described first substantially flat plane that is substantially co-planar with the sole under-surface  54  of the mounting plate  50 . 
       FIG. 5  also illustrates a spring  102  that presses against a post  42  inserted into the post mounting hole  40  ( FIG. 1C ). Spring  102  is an example of a retraction device configured to move the cutting edge  32  away from the cleaving edge  12  when the hydraulic ram  100  is deactivated. An actuator is a component that acts as a power device and as a retraction device. In some embodiments the power device portion of an actuator is separate from the retraction device portion, such as with hydraulic ram  100  and spring  102 . In some embodiments the power device portion of an actuator and the retraction device portion of an actuator are combined into a single mechanism, such as a double-acting hydraulic ram. 
     Relative movement between a cutting edge and a shearing edge is achieved by propelling the cutting edge and the shearing edge together in a mounting structure, and by repelling the cutting edge and the shearing edge apart. In some embodiments this propelling and repelling may be achieved by an actuator that is coupled to a cutting blade (such as hydraulic ram  100  is coupled to the cutting blade  30  by the tang  38  in  FIG. 5 ) to move a cutting edge (e.g., cutting edge  32 ) toward a shearing edge (e.g., the cleaving edge  12 ) that remains substantially stationary with respect to the mounting structure. In alternative embodiments the propelling and repelling may be achieved by an actuator coupled to a shearing block (e.g., the cleaver  10 ) to move a shearing edge (e.g., the cleaving edge  12 ) toward a cutting edge (e.g., the cutting edge  32 ) while the cutting edge remains substantially stationary with respect to the mounting structure. In some embodiments the propelling and repelling is achieved by relative motion of the cutting edge and the shearing edge with respect to the mounting structure. 
       FIG. 5  also illustrates a protrusion of material  110  that is positioned for clipping. The cleaving edge  12  (which is an example of a shearing edge) is configured to engage a first portion  112  of the protrusion of material  110  and the cutting edge  32  is configured to engage an opposing second portion  114  of the protrusion of material  110  for clipping the protrusion of material  110 . 
       FIG. 6  illustrates further features of an embodiment of an apparatus  120  for clipping a protrusion of material. The apparatus  120  includes the elements depicted in  FIGS. 1A ,  1 B,  1 C,  2 ,  3 ,  4 , and  5 . The apparatus  120  is attached to a pump  122  that is used to pressurize a hydraulic ram (i.e., the hydraulic ram  100  of  FIG. 5 ) through a pressure line  124 . In the embodiment of  FIG. 6  the apparatus  120  also includes a handle  126  and a knob  128  that may be used to position the apparatus  120  over a protrusion of material on a substrate. Knob  128  may include a threaded extension that holds cleaver  10  ( FIG. 3 ) stationary with respect to mounting plate  50  ( FIG. 3 ). In this embodiment a momentary switch  130  is installed on the handle  126 , and the momentary switch  130  is used to actuate the pump  122  through a control line  132 . The momentary switch  130  installed on the handle  126  as illustrated in  FIG. 6  is an example of a momentary switch proximate to an apparatus (e.g., apparatus  120 ). 
     Typically the pump  122  is electric powered and the momentary switch  130  is an electrical switch and the control line  132  is an electrical line. When momentary switch  130  is depressed, a signal (typically an electrical continuity) is established through control line  132  to actuate the pump  122 . When the pump  122  is actuated the hydraulic ram  100  ( FIG. 5 ) is pressurized through pressure line  124 . As hydraulic ram  100  is pressurized it moves the cutting edge  32  toward the cleaving edge  12 . The longer that momentary switch  130  is depressed, the higher the pressure that is provided to the hydraulic ram  100  (up to the design limit of the pump  122 ). This configuration allows the apparatus  120  to use only the minimum amount of power required to cut the protrusion. When the momentary switch  130  is released, a signal (typically an electrical discontinuity) is established through control line  132  to de-actuate the pump  122 . When the pump  122  is de-actuated the hydraulic ram  100  is depressurized and a retraction mechanism (e.g., spring  102  of  FIG. 5 ) moves the cutting edge  32  away from the cleaving edge  12 . 
     The apparatus  120  in  FIG. 6  also includes an observation window  134  that is configured to permit an operator to view the cleaving edge (e.g., the cleaving edge  12  in  FIG. 3 ) and the cutting edge (e.g., the cutting edge  32  in  FIG. 3 ) while a protrusion is clipped by the apparatus  120 . The apparatus  120  also includes a capture box  136 . In the embodiment of  FIG. 6  the observation window  134  is installed in the capture box  136 , but in other embodiments an observation window may be otherwise configured. The capture box  136  is configured to preferentially collect the protrusion of material clipped by the apparatus  120 . The term “preferentially collect” refers to an arrangement where the capture box is configured to collect most, but not necessarily all, portions of protrusions of material clipped by the apparatus  120 . For example, in the embodiment of  FIG. 6 , the capture box  136  includes an opening  138  to permit easy removal of protrusions clipped by the apparatus  120 . The opening  138  may permit a particular clipped protrusion or a portion of a particular clipped protrusion to eject from the apparatus  120  without collection by the capture box  136 . To reduce the risk of injury to an operator form such an ejection, the embodiment of  FIG. 6  includes a deflection plate  140  that is configured to deflect away from the operator a flying protrusion of material ejected through the opening  138 . 
     In summary, the embodiments disclosed herein describe various features of an apparatus for clipping a protrusion of material. The foregoing descriptions of these embodiments have been presented for purposes of illustration and exposition. They are not intended to be exhaustive or to limit the claimed invention to the precise forms disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the invention and its practical application, and to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.