Patent Publication Number: US-2022231493-A1

Title: Cutting Blade and Cutting Depth Control Device

Description:
FIELD OF THE INVENTION 
     The present disclosure relates to cutting devices, and more particularly, to a device for limiting the depth of a cut made through an electrical cable with a rotating cutting blade of a cable preparation machine. 
     BACKGROUND 
     The preparation of wire and cable for use in electrical systems is time consuming and expensive. In some applications, a cable may comprise several layers, including those made of materials which are difficult to selectively remove or otherwise process during, for example, connectorization of the cable. High voltage electrical cable is one such application requiring significant effort to process the cable ends prior to use. Referring generally to  FIG. 1 , a typical high voltage electrical cable  10  comprises a central wire or conductor  12  which is covered with a silicone insulation layer  14 . A foil layer  15  is helically wrapped around the insulation layer  14 , onto which a conductive woven or mesh braiding layer  16  is placed. Finally, an outer silicone insulation layer  18  may be applied over the braiding layer  16 . Depending on the application, it may be desired to remove any one or more of these layers to expose an underling layer without contacting the underlying layer and potentially causing damage thereto. This may be particularly challenging when removing each of the silicon insulation layers  14 , 18  to reveal or expose the conductive braiding layer  16  and/or the central conductor  12 . 
     According to high voltage cable processing of the prior art, a high voltage-cable preparation (HV-CP) machine perform a first rotary cut around the cable in order to partially cut through an outer layer of the cable (e.g., the insulation layer  18  of the representative cable  10 ). However, due in part to its flexible nature, the cable is typically not perfectly straight during this cutting operation, and the accuracy of the depth of the cut is limited as the cable rotates in a non-concentric manner. Accordingly, this first rotary cut can only be performed to a depth approximately halfway through a thickness of layer, ensuring the blades do not inadvertently contact an underlying layer, for example, the braided metal layer  16  of the cable  10 . Once the first rotary cut is made, another cut is performed that “chops” through the remainder of the insulation in a non-rotating manner. As the blades are not rotated in this operation, the detrimental effects of any inherent axial misalignment of the wire or cable are minimized, and the cut can be made with greater precision. This second cut, however, requires significant additional time, and is required on both the outer and inner insulation layers, by way of example. 
     Accordingly, there is a need for improved systems and methods for accurately and expediently performing these types wire or cable preparation operations. 
     SUMMARY 
     In one embodiment of the present disclosure a cutting blade assembly for use with a rotating cable preparation device or machine is provided. The assembly includes a cutting blade defining a cutting edge and adapted to attach to a rotating member of the cable preparation device. The cutting blade assembly is selectively movable in a cutting direction for at least partially cutting a cable held by the device. The assembly further comprises a blade stop arranged adjacent to the cutting edge of the blade and defining a stop surface. The stop surface is positioned at a predetermined distance from the cutting edge of the blade in a direction opposite the cutting direction and extends in a direction generally perpendicular to the cutting direction and generally parallel to an axis of the cable or the rotational axis of the device. 
     In another embodiment of the present disclosure, a cable processing machine comprises a rotating member rotatable about an axis. A plurality of blade holders of the machine are rotatably attached to the rotating member and support a respective one of a plurality of blade assemblies. Each blade assembly comprises a blade attached to the blade holder, and a blade stop attached to the blade holder and arranged adjacent the blade. The blade stop defines a stop surface arranged at a predetermined distance from a cutting edge of the blade in a depth direction of the blade and extends in a direction generally perpendicular to a cutting direction of the blade. The stop surface is adapted to engage with an outer surface of the cable when the cutting edge of the blade has reached a predetermined cutting depth corresponding to the predetermined distance for limiting the depth of the cut. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described by way of example with reference to the accompanying Figures, of which: 
         FIG. 1  is a perspective view of an exemplary multi-layer high voltage electrical cable useful for describing embodiments of the present disclosure; 
         FIG. 2  is a front view of an HV-CP machine utilizing a plurality of cutting depth control devices or blade stops according to an embodiment of the present disclosure for processing a cable; 
         FIG. 3  is a partially exploded view of a cutting assembly of the HV-CP of  FIG. 2 ; 
         FIG. 4  is an isolated view of a plurality of rotary cutting blades and associated cutting depth control devices according to an embodiment of the present disclosure; 
         FIG. 5  is a perspective view of one of the cutting depth control devices according to an embodiment of the present disclosure; 
         FIG. 6  is a detailed perspective view of the HV-CP machine of  FIG. 2  performing a cable processing operation; and 
         FIG. 7  is a side cross-sectional view of the HV-CP machine of  FIG. 2  performing the cable processing operation shown in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Exemplary embodiments of the present disclosure will be described hereinafter in detail with reference to the attached drawings, wherein like reference numerals refer to like elements. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will convey the concept of the disclosure to those skilled in the art. In addition, in the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it is apparent that one or more embodiments may also be implemented without these specific details. 
     Embodiments of the present disclosure are directed to an improved cutting blade assembly for use in a rotating cable preparation machine or device. According to an embodiment, the cutting blade assembly includes a plurality of cutting blades, with each blade having a depth control device or blade stop associated therewith. The blade stop is arranged adjacent to a cutting edge of the blade, and is offset a predetermined distance from the cutting edge in a depth direction of the blade. During processing, with the blade penetrating a wire or cable to the predetermined distance, the blade stop engages with or abuts an outer surface of cable such that the blade is prevented from advancing further into cable, thus limiting the depth of the cut. Moreover, when processing a generally flexible wire or cable, the blade stop acts to bias the cable toward an ideal cutting axis (or its ideal central axis), thus centering the cable with respect to the cutting blades of the cable preparation machine. More specifically, as one of the blade stops makes contact with the cable during a cutting operation, the cable is biased radially toward an ideal axial position and into contact, or into further contact, with a remaining number of additional cutting blades. In this way, the accuracy and precision of the cut achievable by the blades is increased, and potential damage to underlying cable layers is avoided. 
     Embodiments of the present disclosure are described herein in the context of their use with an exemplary HV-CP machine. As shown in  FIGS. 2 and 3 , an HV-CP machine  100  includes a base  110  to which a rotating pulley assembly  120  is mounted. In one embodiment, the pulley assembly  120  includes a first pulley  122  and a second pulley  124 , each independently rotatably mounted to the base  110  about a central axis A. The pulleys  122 , 124  may be belt driven, by way of example only, and comprise central openings along the axis A through which an end of a cable  10  to be processed is passed. The cable  10  may be fixedly held by a camping device (not shown) of the machine  100 , such that it is fixed in position relative to the rotating pulley assembly  120 . 
     A plurality of blade holders or cutting heads  140  (e.g., three) are rotatably attached to the pulley  122  via corresponding axles  112 . The rotational or radial position of each blade holder  140  is adjustable about the axle  112  for adjusting the position of a corresponding cutting blade  180  attached thereto relative to the cable  10 . By way of example only, each blade holder  140  may be operatively connected to the rotating pulley  124  for achieving the rotatory adjustment of the blade holders. Specifically, a cam follower  125  extending from and attached to the pulley  124  may engage with a corresponding aperture  145  formed in an end of a body  142  of the blade holder  140  opposite the axle  112 . In this way, altering the relative radial positions of the pulley  122  and the pulley  124  is operative to alter the angle of the cutting head  140  about the axle  112 , and thus the position of the blade  180  relative to the cable  10 . By connecting blade holder  140  to both the first and second pulleys  122 , 124  in this manner, the rotational motion of each blade holder  140  about a respective axle  112  is synchronized, ensuring the relative positions of the cutting blades  180  are maintained as they are selectively moved into and out of contact with the cable  10  in the radial directions. The blade holders  140  may also be moveable in an axial direction along the illustrated axis A. In this way, after a cutting operation is performed, cut material may be removed by translating the holders  140  (and the blades  180 ) axially, pulling the cut material from a remainder of the cable. 
     Still referring to  FIGS. 2 and 3 , the body  142  of each blade holder  140  defines an aperture  144  for receiving a respective one of the axles  112  in a rotatable manner. A slot  146  is defined in a front face of the body  142  and is sized to receive a cutting depth control device or blade stop  200  according to an embodiment of the present disclosure, as well as a respective one of the cutting blades  180 . One or more locating pins  147  may be arranged within the slot  146  and extend from the front face thereof for engaging with corresponding apertures formed through the blade stop  200  and the cutting blade  180  for fixing their position relative to the blade holder  140 . Further, a threaded aperture may be formed into the body  142  in the area of the slot  146  for receiving a fastener  152  for securing the blade stop  200  and the blade  180  to the holder  140 . 
     Referring to  FIG. 4 , a cutting blade assembly  170  according to an embodiment of the present disclosure includes a plurality of pairs (e.g., three pairs) of cutting blades  180  and corresponding blade stops  200 . The blade and blade stop pairs are arranged generally 120 degree apart with respect to the central axis of rotation of the cutting machine  100  and/or the ideal axial center of a cable held therein. See axis A of  FIG. 2 . Each cutting blade  180  includes a body  182  defining a cutting surface  184 . In the exemplary embodiment, a cutting or sharpened edge  185  of the cutting surface  184  comprises an arcuate or curved profile defining a portion of a circle, with a radius of curvature defined about a center of the assembly  170 , or the rotational axis A of the cutting machine. In this way, as each of the blades  180  converge toward the ideal radial center of a cable, the cutting edges  185  likewise converge to define a continuous or near continuous circular cutting edge (i.e., forming a majority of a circle) for simultaneously engaging with and cutting a majority of an outer circumferential surface of the cable. From the cutting edge  185 , the cutting surface  184  defines a curved or partially-spherical profile extending through a thickness of the body  182  toward a front face  183  thereof. 
     Still referring to  FIG. 4 , the body  182  further defines a plurality of locating apertures  186  for receiving the locating pins  147  or other locating or keying features of the blade holder  140  for accurately fixing the position of the cutting blade  180  relative to the holder. The body  182  may define a stepped and/or slotted aperture  187  for receiving a respective one of the fasteners  152  in a recessed manner for securing the blade  180  and the blade stop  200  to the holder  140 . As illustrated, one or more of the apertures  186 , 187  may be slotted, elongated over otherwise over-sized in profile, facilitating the fixation of the cutting blades  180  and/or the blade stops  200  of each pair in a number of varying positions, for adjusting a cutting depth of the assembly  170 . The body  182  further defines a tapered mid portion  189  such that a width of the body  182  is reduced from an end thereof defining the cutting surface  184  compared to that of the end mounted to the holder  140 . The reduced width of the cutting end of the body  182  creates additional clearance, allowing for adjacent blades/stop pairs to be arranged in closer proximity to one another as they converge during a cutting or processing operation. As a result, spacing between adjacent blades can minimized during cutting, improving the cutting quality. 
     With particular reference to  FIGS. 4 and 5 , the depth control device or blade stop  200  according to an embodiment of the present disclosure includes a body  202  having a profile generally corresponding to or matching that of the body  182  of the blade  180 , including a first end having a width and shape corresponding to that of the slot  146  formed in the holder  140 , a tapered mid portion  209 , and a narrowed second end defining an engaging or stop surface  210 . The body  202  of the blade stop  200  further defines locating apertures or openings  206  for receiving the pins  147  of the holder  140 , as well as a clearance slot  207  corresponding to the stepped slot  187  of the blade  180  for receiving the mounting fastener  152 . As set forth above, the locating openings  186 , 206  of the blade  180  and/or the blade stop  200  may be slotted such that their fixed positions relative to the holder may be adjusted. Likewise, in some embodiments, only the apertures  206  of the stop  200  may be slotted, permitting the adjustment of the allowable cutting depth of the blade  180  by altering the position of only the blade stop  200 . 
     As described above, the stop or engaging surface  210  of the blade stop  200  is configured to oppose and abut the outer surface of the cable during a cutting operation. Specifically, the stop surface  210  defines a profile that extends in a smooth, linear manner across its thickness, or in a direction parallel to the axis of rotation A of the cutting machine and/or the axial direction of the cable. The stop surface  210  is further curved in a radial direction of the cable with which is engages, or curved about an axis of curvature coaxial with the axis of rotation A of the cutting machine and/or the cable. In this way, the stop surface  210  defines a curved profile matching that of an outer surface of the cable with which it engages. 
     Referring now to  FIGS. 6 and 7 , the cutting blade assemblies  170  are shown engaged with the cable  10  during a cutting operation performed by the HV-CP machine  100 . The cutting blade assemblies  170  are configured to move in radially inward and outward directions relative to the axis of rotation A via a corresponding motion of the blade holders  140 . As illustrated, the blade assemblies  170  have been biased radially inward in a cutting direction, with the leading or cutting edges  185  of the blades  180  cutting through the outer insulation layer or sheathing  18  of the cable  10 . The stop surface  210  is positioned directly adjacent to the cutting surface  184  of the blade  180  in an installed position, with the stop surface offset from the leading or cutting edge  185  of the cutting blade  180  in a radially-outward direction of the cable, or in a direction opposite the cutting direction. More specifically, the cutting edge  185  of the cutting blade  180  is defined at a vertex defined between a first vertical sidewall of the cutting blade and a second sidewall. In an installed position, the stop surface  210  of the blade stop  200  is arranged directly adjacent to and abutting the first vertical sidewall of the cutting blade  180 . By locating the blade stop  200  directly adjacent to the cutting blade  180 , the cable is positioned by the blade stop in the most accurate manner with respect to the adjacent blade, minimizing variations resulting from, for example, axial misalignment and/or runout. 
     A predetermined offset distance D (see  FIG. 7 ) between the leading edge  185  of the blade  180  and the stop surface  210  corresponds to the maximum allowable cutting depth of the blade into the cable. Once the blade has cut to the predetermined depth D, the stop or engaging surface  210  of the stop  200  comes into abutting contacting with the insulation layer  18 . After initial contact is made, the stop  200  prevents the blade  180  from engaging further into the insulation layer  18 . Further radially-inward motion of the blade assemblies  170  results in the stop surfaces  210  biasing the cable  10  radially inward, or toward its ideal axial center aligned with axis A. More specifically, as the cable  10  is generally flexible, it should be understood that the stop surface  210  acts to center the cable during the cutting operation, biasing the outer periphery of the cable toward an ideal center position. This is particularly important in the cutting of flexible objects, such as a cable, as the lack of rigidity of the cable would otherwise result in the cable being off-center during cutting operations, limiting the accuracy with which the cut can be made, and thus risking damage to the cable, for example, cutting to an undesired depth. Like the cutting blades  180 , the arcuate nature of the stop or engaging surfaces  210  of the blade stops  200  converge to form a near continuous support surface for the outer surface of the cable, or at least a support surface simultaneously engaging a majority of an outer circumference of the cable (i.e., forming a majority of a circle). In this way, the cable  10  is likewise supported about its outer perimeter in a uniform fashion, further improving the accuracy of the centering function performed by the blade stops  200 , and thus the accuracy and uniformity of the cut. 
     With particular reference to  FIG. 7 , in another embodiment of the present disclosure, the blade stops  200  may be pivotally or otherwise movably mounted to the cutting heads  140 , and supported in an elastic manner, such as by springs  250 . The spring s 250  may apply sufficient force on the blade stops  200  such that they operate in the above-described manner, accurately positioning the cable  10  during cutting and preventing cutting to an excess depth. However, as the blade stops  200  are elastically mounted, additional pressure applied in the radially inward direction by the rotation of the holders  140  may be operative to bias the stops  200  in a direction radially away from the cable, permitting a degree of further engagement of the cutting blades  180  into the cable. Likewise, the blade stops  200  may be formed from an elastic material, imparting similar elastic behavior in the radial direction and permitting cutting depths which vary in either direction from an initial offset distance between the stop surfaces  210  and the leading edges of the blades  185 . The ability to vary the cutting depth without having to manually reposition the cutting blades  180  and/or the blade stops  200  may be useful to an operator performing the cable processing operations for any number of reasons. 
     The foregoing illustrates some of the possibilities for practicing the invention. Many other embodiments are possible within the scope and spirit of the invention. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range. 
     Also, the indefinite articles “a” and “an” preceding an element or component of the invention are intended to be nonrestrictive regarding the number of instances, that is, occurrences of the element or component. Therefore “a” or “an” should be read to include one or at least one, and the singular word form of the element or component also includes the plural unless the number is obviously meant to be singular. 
     The term “invention” or “present invention” as used herein is a non-limiting term and is not intended to refer to any single embodiment of the particular invention but encompasses all possible embodiments as described in the application.