Abstract:
An industrial precision safety cutter and a method of using the same, the industrial cutter having a cutter head. The cutter head has a reinforcing body, a first prong extending from the body, a second prong extending from the body, and a cutting edge extending from the body. The first prong has a rounded end. The cutting edge extends between the first and second prongs. The industrial cutter has an extendable length handle removably connected to the cutter head. The industrial cutter may be used in applications in the nuclear power industry.

Description:
FIELD OF THE INVENTION 
       [0001]    The present specification relates generally to the field of materials cutting devices. In particular, the present specification relates to industrial cutters for cutting materials in applications where safety is important, such as the nuclear industry. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the nuclear industry, and in particular, in the field of maintenance and inspection of nuclear power plants, it is often necessary to deal with covered bundles of wires and fluid lines, heavy industrial storage and shipping bags, fire blanket material, industrial protective matting, manufacturers&#39; packaging and other similar materials. A bundle of wiring, as shown in  FIG. 1 , consists of a series of wires, cables or fluid lines  14  all extending generally in the same direction and covered by a sleeve  12  such as a plastic shrink tube, electrical tape, duct tape or other such covering that holds them together. In order to conduct maintenance it may be necessary to cut open the cover of a bundle of wiring. 
         [0003]    Because the inadvertent cutting of a wire, cable or fluid line can be catastrophic in, for example, the context of a nuclear power plant, maintenance personnel are limited by safety rules sharply limiting which cutters they can use to cut wire bundle covers and the like. For example, ordinary knives are forbidden, as are cutters known as X-Acto™ knives and Olfa™ adjustable cutters, where the blades can be extended up to about 10 cm. In limited cases, Olfa™ knives may be allowed when there is about 1.9 cm or less of exposed blade, biased with a spring to a closed or retracted position. Using this approved version of Olfa™ knives is difficult and awkward for maintenance personnel, because they have to constantly be forcing the knife to an open position while using it. 
         [0004]    Another cutter that is sometimes permitted for use in this context is a seatbelt cutter. However, because of its configuration, it is very limited in how it can be used and what it can cut. 
         [0005]    Furthermore, because of safety concerns relating to dirt, dust, bodily oils and the like, together with radiation concerns, maintenance personnel in nuclear plants and similar environments often wear at least two pairs of gloves, one on top of the other, while doing maintenance work, thus greatly reducing dexterity. This makes using the narrow range of permitted cutters all the more difficult. 
         [0006]    Apart from the special safety concerns associated with contexts like nuclear power plants, traditional industrial materials cutters have a variety of flaws that are known to persons skilled in the art. For example, these cutters often have exposed blades shaped so as to create a risk of cutting or jabbing the user, or someone nearby, by mistake. 
         [0007]    Some examples of cutting devices include the following: 
         [0008]    U.S. Pat. No. 5,896,667 discloses a piercing-cutting device for plastic wrap removal from an object which includes a blade and handle. 
         [0009]    U.S. Pat. No. 3,972,117 discloses a disposable blade device having two ends, one having a blunt point and a narrow stitch picker with a concaved edge portion between them and the other having two blunt projections joined by a concave sharpened area. The device is made from disposable razor blade stock or the like. 
         [0010]    U.S. Pat. No. 2,764,814 discloses a ripping tool for tailoring and sewing. 
         [0011]    U.S. Pat. No. 5,142,780 discloses a small, hand-held tool for removing the outer sheath of plastic material covering a bundle of individually insulated electrical conductors. The tool has a blade between a shoe and a metal shank. 
         [0012]    U.S. Patent Publication No. 2002/0026711 discloses a plastic sheath cutting and slitting hand tool which includes a handle and a generally flat sheath engaging and slitting edge. 
         [0013]    U.S. Pat. No. 6,182,364 discloses a safety stock carton knife including a handle and a blade projecting from the handle and having two lateral edges and an outer end. 
         [0014]    U.S. Pat. No. 6,964,100 discloses a knife guard that selectively guards a tip of a blade of a knife while exposing at least a portion of a cutting edge of the blade which may be used by a user for field dressing an animal. 
         [0015]    U.S. Pat. No. 3,572,189 discloses a tool for shaving and stripping the impregnated outer layer from the insulating jacket of an electrical conductor cable. 
         [0016]    U.S. Pat. No. 2,637,904 discloses a knife or scalpel with a thin flat metal blade. 
         [0017]    U.S. Pat. No. 1,474,107 discloses a safety razor blade holder. 
         [0018]    U.S. Pat. No. 3,187,354 discloses a combination hunting tool, hatchet and axe with a knife-like gutting edge. 
         [0019]    U.S. Pat. No. 3,621,899 discloses a convertible hand utensil with an interchangeable implement portion that is releasably connected to a handle portion. 
         [0020]    U.S. Patent Publication No. 2003/0150117 discloses a utility knife with a cutting blade that is extendable to a desired length from the knife handle. 
         [0021]    U.S. Pat. No. 3,100,935 discloses a tool for the ripping of seams and like purposes including a blade inset between the edge of a shank and an opposite blunt edge. 
         [0022]    U.S. Patent Publication No. 2007/0245572 discloses a knife having a handle, a blade mounted on the handle and a blade guard. 
         [0023]    U.S. Pat. No. 5,539,983 discloses a safety stock carton knife having an elongated handle having a blade projecting from the end of the handle having an outer sharp edge and the blade and outer edge of the blade converging to form a juncture with a blunt knob. 
         [0024]    U.S. Pat. No. 4,198,751 discloses a skinning knife having a notched cutting edge which opens towards the knife handle and an enlargement on the one side of the notch which permits the user to slice the hide of an animal without cutting the underlying flesh. 
         [0025]    U.S. Design Pat. No. D518,349 shows a utility knife for horse/bull riders which appears to show a cutting edge between two parts of a piece which extends from a handle. 
         [0026]    U.S. Pat. No. 1,498,753 discloses a carcass opening device with a knife-shaped cutting blade having a sharp point and, near the handle, a blade arm at the end of which is fixed a ball. 
         [0027]    U.S. Pat. No. 6,195,896 discloses a safety knife with a handle, a main blade mounted on the handle with a pointed end-part of the cutting edge of the blade projecting from the handle at an obtuse angle and a guard mounted on the handle to shield the projection portion of the blade. 
       SUMMARY OF THE INVENTION 
       [0028]    What is desired is a cutter that is versatile and has improved safety characteristics. The cutter preferably is strong and durable and allows for precise cutting. Such a cutter preferably meets the stringent safety requirements of the nuclear power industry or other industries in which safety is a primary concern. 
         [0029]    According to one embodiment there is provided a precision safety cutter, comprising: a length-adjustable handle, and a cutter head, the handle and cutter head being configured to be detachably attachable to one-another; with the cutter head comprising a body, and a cutting edge on the body, wherein at least one portion of the cutting edge is recessed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    Reference will now be made, by way of example only, to preferred embodiments of the inventions and in which: 
           [0031]      FIG. 1  is a section view of wires or cables within a sleeve or cover; 
           [0032]      FIG. 2  is a perspective view of an embodiment of a cutter head of an industrial precision safety cutter having a threaded shank; 
           [0033]      FIG. 3  is side view of an embodiment of a cutter head of an industrial precision safety cutter; 
           [0034]      FIG. 4  is a side perspective view of the embodiment of a cutter head of the industrial precision safety cutter of  FIG. 3  with a protective blade cover; 
           [0035]      FIG. 5  is a side perspective view of an embodiment of a protective blade cover; 
           [0036]      FIG. 6  is a side view of the embodiment of a cutter head of the industrial precision safety cutter of  FIG. 4  with the embodiment of the protective blade cover of  FIG. 5 ; 
           [0037]      FIG. 7  is a side view of the embodiment of a cutter head of the industrial precision safety cutter of  FIG. 3 ; 
           [0038]      FIG. 8  is a side view of an embodiment of a handle of an industrial precision safety cutter; 
           [0039]      FIG. 9  shows the cutter head carrying shaft carrying the cutter head and blade cover, separated from the grip; and 
           [0040]      FIG. 10  shows the cutter head carrying shaft carrying the cutter head and blade cover, separated from the grip. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0041]      FIG. 1  shows a wire or cable bundle, including wires or cables  14 , and bundle cover  12 . 
         [0042]      FIGS. 2-3  and  7  each show a cutter head  18  of a precision safety cutter  16 . The cutter head  18  includes a body  20 . The body  20  includes a reinforcing body portion  21  and a cutting edge carrying portion  23 . Positioned on the cutting carrying portion  23  is a cutting edge  25 . 
         [0043]    As can be seen in  FIG. 2-4 , at least a portion of the cutting edge  25  is recessed. Preferably, this recessed portion  26  of cutting edge  25  is substantially in a U-shape. The body  20  preferably includes a first prong  24  and a second prong  22  depending from the cutting edge carrying portion  23 . Most preferably, the first prong  24  is longer than the second prong  22 , with the first prong  22  being configured as a puncture element  27 . In particular, the first prong  24  is preferably configured to have puncture point  30 , which can be used to puncture a material to be cut as desired. 
         [0044]    Preferably, the cutter head further comprises a spacer  38 , positioned on the body so as to space, during cutting, the cutting edge  25  from material not to be cut, while permitting the cutting edge  25  to cut material to be cut. Preferably, the spacer  38  comprises a bulbous element, most preferably in the form of a metallic ball, positioned adjacent to an end of cutting edge  25 . 
         [0045]    Thus, in the most preferred embodiment, the cutting edge carrying portion  23  of body  20  includes a first prong  24  having a first end  31 , and a second prong  22  having a second end  33 . The cutting edge  25  extends substantially in a U-shape between the first end  31  and the second end  33 . The bulbous element is preferably positioned on the second prong  22  so as to space, during cutting, the cutting edge  25  from material not to be cut, while permitting the cutting edge  25  to cut material to be cut. Most preferably, the bulbous element  38  is positioned at second end  33 . 
         [0046]    It can now be appreciated how the precision safety cutter operates. If it is necessary to make a hole in a wire bundle cover or the like in order to begin cutting it, the puncture element  27 , and in particular point  30 , can be used to carefully puncture a hole in the material to be cut. The first prong can then be removed from the hole that was just punctured in the material to be cut. The second prong  22 , carrying ball  38 , can then be inserted into the hole that was punctured. The ball  38  functions to space the cutting edge  25  away from surrounding material not to be cut. Meanwhile, cutting edge  25  can be abutted against the material to be cut, and in response to the pressure, cutting edge  25  is advanced through the wire bundle cover or other material to be cut. Thus, the spacer  38  permits the cutting edge  25  to cut the wire bundle cover, or other material to be cut, while spacing from the cutting edge  25  from other material not to be cut, such as the wires, cables, fluid lines or other sensitive/fragile components within the bundle. 
         [0047]      FIGS. 4 and 6  show cutter head  18  with a removal cutter cover in the form of a protective blade cover  32 .  FIG. 5  shows the cover  32  alone. Cover  32  is mountable on the cutter head  18 , for example, as shown in  FIG. 4 . Cover  32  preferably extends over at least the first prong  24 , and covers the pointed end  30 . However, the cover  32  is preferably configured such that a portion  29  of cutting edge  25  is exposed for cutting, while the puncture element  27  is covered. Preferably, the exposed portion  29  of the cutting edge  25  is generally concave. It is also preferred that the cover  32  does not cover second prong  22  or the ball  38 , so that the ball  38  can be used as a spacer during cutting, even when the cover  32  is mounted to the cutter. 
         [0048]    Preferably, the cover  32  is mountable to the cutter head  18  in a snap fit, with a portion of the cover  32  snap fitting onto female portion  48  of cutter head carrying shaft  50 . The cover  32  is shown in  FIG. 5 . It includes an extended pointed end cover  42  which extends over the first prong  24  and, in particular, puncture element  27  (including pointed end  30 ). In the embodiment shown in  FIG. 5 , cover  32  includes a section  44  covering the reinforcing portion  21  of body  20 , as well as a rear cover  47  which extends around female portion  48 . Preferably, the section  44  and reinforcing body portion  21  are configured such that section  44  snap fits to portion  21 , holding cover  32  in place. However, other forms of snap fit are comprehended by the invention, as are other configurations of cover  32 . 
         [0049]    Although, in the preferred embodiment, cover  32  is mounted to cutter head  18  and shaft  50  by a snap fit, other means of mounting are comprehended by the invention. For example, the cover  32  could be mounted by a slide fit or an elastic connection. A magnetic mounting is also comprehended. What is most preferred is that the cover  32  covers the puncture element  27 , while leaving exposed a (preferably concave) portion  29  of the cutting edge  25  for cutting. 
         [0050]    In the preferred embodiment, the cover  32  covers not only the puncture element  27 , but the portion  35  of the cutting edge  25  running along the first prong  24  adjacent to the puncture element  27 . 
         [0051]    As shown in  FIG. 2 , the second prong  22  has a width w 2  and a height h 2 , and the first prong  24  has a width w 1  and a height h 1 . In some embodiments, the height h 1  will be no greater than three times the width w 1 , and the height h 2  will be no greater than three times the width w 2 . That is, the first and second prongs each will have a height-to-width ratio that is no greater than three-to-one. It will be appreciated that if the prongs  22 ,  24  are too long and narrow, they may be at risk of breaking, particularly when cutting tough materials. The breaking of one of the prongs, or of the body  20  generally, when the cutter is in use can be particularly dangerous in certain industries, such as the nuclear reactor industry referred to above. It is therefore preferable that the body  20 , including the prongs  22 ,  24 , have a strong, heavy duty construction. As for the specific widths and heights, they may vary depending on the application for which the safety cutter is built. 
         [0052]    The reinforcing portion  21  of body  20 , as shown in  FIG. 2 , is preferably a solid potion of the cutter head  18  that has substantial additional thickness relative to the prongs  22 ,  24  and the cutting edge carrying portion  23 . The added thickness of reinforcing portion  21  increases the strength and durability of the cutter head  18 . In applications where it is not as important for cutter head  18  to have a heavy duty construction, the invention comprehends a cutter head  18  without an extra-thick reinforcing portion  21 . 
         [0053]    Referring now to  FIG. 6 , it will be appreciated that the cutter of the present invention is preferably configured to reduce the risk of a user&#39;s finger, or other body part, being cut or stabbed by the safety cutter. Thus, it is preferred that, when the cover  32  is mounted to the cutter head  18 , the width or exposed portion  29  of cutting edge  25  (shown by reference character G, which stands for “Gap”) is less than the width of even a small finger of a user. Together with the fact that the cutting edge  25  is recessed, this preferred feature would further reduce the risk of a user being cut. 
         [0054]    Preferably, the gap G is less than 1.3 cm wide, and most preferably, the gap G is between 2 mm and 10 mm wide. Reference character G corresponds to the width of the exposed portion  29  of the cutting edge when the cover  32  is mounted to the cutter head  18 . 
         [0055]    It will be appreciated that the cover  32  also enhances the safety of the cutter  16 . Puncture element  30  is covered by cover  32 , so the risk of a user being inadvertently jabbed or punctured is much reduced. The cover  32  can be mounted to the body  20  when the cutter  16  is in use, and removed only if it is necessary to puncture a material with puncture element  30 . If such puncturing is not required, then cutting can be done with cover  32  in place, since a portion  29  cutting edge  25  is left exposed for cutting when cover  32  is mounted to the cutter  16 . 
         [0056]    The precision safety cutter may be made from any suitable material that provides the necessary strength. In many ordinary applications, steel, such as carbonizing hardened/case hardened steel, with or without nickel plating, would provide adequate strength and stiffness. 
         [0057]    Preferably, the cutter further comprises a length-adjustable handle  45  shown in  FIGS. 8 ,  9  and  10  most preferably including a screwdriver-type grip  28  that is formed for easy, effective and comfortable gripping of the handle, while at the same time providing for ease of manipulation for the user. Preferably, the handle  45  and cutter head  18  are detachably attachable from one another. Most preferably, the shank  34  of cutter head  18  comprises an externally threaded shaft  46 , while the handle  45  comprises an internally threaded female portion  48  configured to receive the shaft  34 . Preferably, portion  48  is positioned at the end of cutter head carrying shaft  50  distal from grip  28 . In use, the handle  45  and cutter head  18  are attached by screwing the shank  34  into the female portion  48  of the shaft  50 . The pieces are screwed together tightly to provide a stable safety cutter. 
         [0058]    The length adjustable handle  45  preferably includes a cutter head carrying shaft  50  attached to and movable in and out of grip  28  to adjust the length of handle  45 . In the most preferred embodiment, actuator  52  is mounted on shaft  50  and grip  28  in a spring-loaded mount. When in its outward unactuated position (away from grip  28 ), the actuator  52 , because it is biased outward by a spring, holds a ball bearing (not shown) against a track means  60  running along shaft  50  to hold shaft  50  in place. The track means  60  comprises a line of indentations  62  for receiving the ball bearing. When actuator  52  is actuated (by pressing it toward grip  28  against the force of the spring loading) the ball bearing is liberated from the track means  60  and the shaft  50  can be pulled out of grip  28  to extend length of handle  45 , or pushed in to contract the length. When actuator  52  is then released, the spring loading moves actuator  52  to a locking position where the ball bearing is forced against the indented track means, thus locking shaft  50  in place relative to grip  28 . 
         [0059]    Preferably, the grip  28  is hollow, with an opening  54 , allowing spare cutter heads to be inserted into and contained in grip  28 . The opening is preferably covered by a threaded plug cap  56 , the cap  56  may be held in place by other means, such as a snap fit. Preferably, the grip  28  is made of a high friction plastic or rubber for ease of holding, and for comfort. 
         [0060]    It will be appreciated that the preferred length-adjustable handle is easy to use. Actuator  52  can be depressed with the thumb and forefinger of a user&#39;s hand. The user&#39;s other hand can be used to grip cutter head carrying shaft  50  to extend or retract handle  45  by moving shaft  50  out of or into grip  28 . 
         [0061]    It will be appreciated that the invention comprehends other forms of length-adjustable handle besides the embodiment shown in  FIG. 8 . For example, the handle could comprise a grip with a shaft that folds or unfolds to adjust handle length. Other embodiments are also comprehended. 
         [0062]    The particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims. 
         [0063]    While the preferred embodiments have been described in detail, it will be appreciated that the invention comprehends other embodiments as well. For example, while less preferred, the cutter head may take a different form than the preferred form described in detail herein and still be comprehended by the invention.