Patent Publication Number: US-2004055160-A1

Title: Cable stripper

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The invention relates to hand tools, and in particular, the invention relates to a portable cable stripper automatically adjustable to accommodate differently dimensioned jacketed cables and safely removing jackets from these cables in a simple and efficient manner.  
       [0003] 2. Background of Technological Field  
       [0004] It is difficult to imagine our life without a limitless variety of electro-powered devices. What is less obvious is that all of these devices are provided with innumerous cables connecting devices to one another and to power sources as well as providing communication between separate components within the same device. Many cables have jackets having outer diameters varying from very small to gigantic. Cable connections involve stripping jackets from cables to be connected, wires and conductors, and, quite often, such stripping is an onerous and unsafe task.  
       [0005] U.S. Pat. No. 6,308,417, which is commonly assigned with the present application and incorporated herein by reference, discloses a cable stripper which enjoys a well-deserved success. However, the cable stripper disclosed in this patent has a complex structure associated with a relatively high manufacturing cost.  
       [0006] It is, therefore, desirable to provide a cable stripper having a simple structure that is easy to adjust, safe to use, and that can provide an easy access to difficult to reach locations.  
       3. SUMMARY OF THE INVENTION  
       [0007] It is, therefore, an object of the invention to provide a portable cable stripper having an easily adjustable structure for reliably holding differently dimensioned jacketed cables during a stripping operation.  
       [0008] Another object of the invention is to provide a portable cable stripper having a resiliently-biased blade assembly to prevent the cable to be stripped from being damaged during a stripping operation.  
       [0009] Yet a further object of the invention is to provide a portable cable stripper having a guide assembly for displacing the cable stripper along a straight cutting line.  
       [0010] Consistent with the foregoing objects, the inventive portable cable stripper is automatically adjusted to grip differently dimensioned jacketed cables with a resiliently-biased blade holding carriage. To accomplish it, the blade holding carriage slides towards the periphery of the jacketed cable and presses against it so as to position the jacketed cable in a cutting position, in which the cable and the cable stripper can move relative to one another only upon applying an external force.  
       [0011] An advantage of the resiliently biased blade holding carriage it provides a reliable and easily adjustable grip of the portable cable stripper on a jacketed cable, even when such a cable is inconveniently located.  
       [0012] According to another aspect of the invention, a blade assembly is provided with a resilient element retracting a blade from a cutting position after a cut has been completed.  
       [0013] This improvement facilitates an easy switch of the blade between a straight cut, a circumferential cut and a spiral cut. Furthermore, the biased blade is automatically retracted from its cutting position after a lock on the blade is released. Accordingly, the risk that the user can be cut during the switch of the blade positioning is substantially minimized.  
       [0014] In accordance with a further improvement, the portable cable stripper has a convenient guiding assembly stirring the blade along a desired straight line during the stripping operation. This is accomplished by a holder engageable by one hand of the user and mounted on one of the opposite ends of the cable stripper. The opposite end of the cable stripper has an elongated guide column shaped and dimensioned to provide a convenient surface engageable by other hand of the user.  
       [0015] As a result of the guiding assembly, pulling forces exerted by the hands of the user are uniformly distributed along opposite segments of the circumference of the cable to be stripped, which, in turn, prevents twisting of the cable stripper relative to the cable to be stripped. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0016] These and other objects, features and advantages will become more readily apparent when reference is made to the following description taken in conjunction with the accompanying drawings, in which:  
     [0017]FIG. 1 is an isometric view of the cable stripper in accordance with the present invention;  
     [0018]FIG. 2 is an isometric view a portion of the inventive cable stripper illustrating cable guide and blade carriage assemblies;  
     [0019]FIG. 3 is an isometric view of a blade housing;  
     [0020]FIG. 4 is an isometric view of a blade holder; and  
     [0021]FIG. 5 is an isometric view of the blade assembly. 
    
    
     SPECIFIC DESCRIPTION  
     [0022] Referring to FIGS.  1 - 5  in general, and to FIG. 1, in particular, a portable cable stripper  10  includes a V-shaped cable support  12  for receiving a cable to be stripped, a guide column  14  removably attached to the cable support, a blade-holding carriage  16  slidable along the guide column and a guide assembly including a handle  20 , which is attached to an outer side of the cable support.  
     [0023] The portable cable stripper is a labor-saving tool adjustable to remove jackets from rigid fiber optic and plastic jacketed cables having an outer diameter which may vary from about {fraction (3/16)}″ to 2″. In operation, the user initially sets a desirable distance at which a blade  70  (FIG. 5) should penetrate the jacket of the cable. Following it, the blade carriage  16  is pulled outwards from the V-shaped cable support  12  to form a space sufficient to receive the cable, and once the cable is placed on the cable support, the blade carriage automatically slides towards and presses against the periphery of the jacket. Accordingly, the cable is locked between the cable support  12  and the blade carriage  16 .  
     [0024] As illustrated in FIGS. 1 and 2, automatic displacement of the blade carriage  16  toward the cable to be stripped is caused by a spring  68  mounted on a central post  66 , better shown in FIG. 2, and biasing the blade carriage towards the cable support  12 . The post  66  is removably mounted on one side of the cable support and traverses a central hole formed in a flange  22  of the guide carriage, which, thus, has an L-shape. The post further has a thickened outer end sized and shaped to form a seat for the outer end of the spring  68 , the opposite end of which urges against the flange  22  of the blade guide so as to push the latter towards the cable placed on the cable support.  
     [0025] A desired position of the blade carriage can be registered by a carriage lock  26  provided with a screw  84 , which is actuated by a handle  82  so that the screw  84  engages a threaded portion of locking cylinder  58  (FIG. 1). The desired position is ensured when the locking cylinder  58  is pulled against the central post  66 .  
     [0026] Guide recesses  24  formed on the opposite sides of the flange  22  provide linear displacement of the blade carriage in a plane perpendicular to a tangent to the periphery of a circular cable. Preferably, the bottoms of the guide recesses  24  each have a respective surface extending complementary to a peripheral surface of the side posts of the guide column  14 , which are, as shown in FIG. 1, are tubular. However, the cross-section of the posts is not limited to any particular configuration and may be, for example, polygonal.  
     [0027] Disassembly of the cable stripper  10  is simplified by attaching inner ends of the side posts of the guide column  14  (FIG. 1) and of the central post  66  (FIG. 2) to a flange  92  of the cable support  12  by fasteners  90  extending through openings  88 , which are provided on the flange  92 . The guide recesses  24 , better illustrated in FIG. 2, are laterally open to facilitate the installation of the guide column  14 , which is U-shaped and, thus, features a loop easily engageable by the user&#39;s fingers during the transportation of the cable stripper. The bottoms of the guide recesses and the side holes  88  have a uniform radius and are aligned with one another to ensure that the guide column  14  extends substantially perpendicular to a plane in which the guide support  12  lies.  
     [0028] The blade carriage  16  carries a blade assembly  18  including a blade positioning dial ring  56  (FIG. 1), which is rotated by the user to establish a desired position corresponding to the desired depth of penetration of the blade into the jacket of the cable to be stripped. The dial ring  56  is operative to rotate to an initial position corresponding to a zero penetration of the blade  70  which is established when the zero “O” mark of the scale formed on the dial ring is juxtaposed with a top edge of index  38  (FIG. 2). A releasable ring lock  30 , which is mounted on the side of the blade carriage opposite its flange  22 , is operable for locking the dial ring in a position corresponding to the desired penetration of the blade. The ring lock  30  is a spring-biased structure, which, in a normal or locking position, prevents rotation of the dial ring  56 , as will be explained below.  
     [0029] A resilient element of the ring lock, such as a spring  32  (FIG. 1), urges the ring lock  30  towards the locking position. The ring lock is substantially a plate-like element having a center recess  31  (FIG. 2) frictionally engaging the dial ring  56  in the locking position of the ring lock  30 . In response to an external force, the ring lock  30  can move out of the locking position and release the dial ring  56 , so that the latter can be further rotated the desired position corresponding to the selected depth of the blade penetration. Preferably, the index  38  is attached to the ring lock  30  and extends outwards from the blade carriage  16  to terminate flush with the scale for the convenience of the user. The dial ring has a structured surface provided with alternating ribs and troughs slidably engaging a v-shaped edge of the index  38  to indicate the number of turns corresponding to the desired depth of the blade penetration into the cable&#39;s jacket. After the desired position has been set, an external force is ceased, and the ring lock returns to its locking position. Sliding motion of the ring lock  30  relative to the guide carriage  16  becomes possible due to a pair of spaced oblong holes  34  (FIG. 2) formed on the ring lock  30  and traversed by fasteners  36 , which are removably attached to the blade carriage  16 . The fasteners  36  are shaped and dimensioned so as to allow the ring lock&#39;s displacement, which is restricted only by the size of the holes.  
     [0030] The blade assembly  18  further includes a hollow blade housing  40  (FIGS. 2, 3 and  4 ) and a blade holder  60 , better illustrated in FIG. 5. The blade housing  40  extends through an opening formed in the blade carriage  16  and has a hollow interior receiving the blade holder  60  which is sized to controllably rotate within the blade housing, as will be explained below. The periphery of the blade housing  40  is threaded to mesh with a threaded inner surface of a blade cap  100  (FIG. 1), which also acts as a blade lock, as will be explained below.  
     [0031] A U-shaped recess  54  (FIG. 3) formed in the periphery of the blade housing  40  provides a guide channel for a lever  28 , which is removably fixed to the blade holder  60  by a thumb screw  52  (FIG. 1) so as to displace the blade  70  between numerous positions corresponding to radial, axial and spiral cuts of the jacket in the following manner. To make a straight axial or radial cut, the blade holder  60  is provided with a first threaded hole  48  spaced at a 90° angle from a hole  46  traversed by a fastener which interconnects the blade  70  and the blade holder  60 . As the blade holder  60  is inserted through the hollow interior of the blade housing  40 , the hole  48  is accessible through the U-shaped recess  54  (FIG. 3) and receives the threaded end of the thumb screw  52 . Accordingly, the U-shaped recess  54  is formed with a pair of side channels spaced at a 90° angle from one another and a bridging channel extending between the juxtaposed ends of the side channels.  
     [0032] Depending on which of the side channels of the U-shaped recess  54  receives the shaft of the lever  28 , the blade holder  60  along with the blade  70  assume a radial cut position, in which the blade is turned at a 90° angle with respect to the axis of the cable, or an axial cut position, wherein the blade  70  extends parallel to the axis.  
     [0033] Turning to FIGS. 4 and 5, the inner end  102  of the blade holder  60  is recessed to receive the blade  70  removably attached to the inner end by a fastener and extending substantially flush with the rest of the blade holder. The outer end  64  of the blade holder provides a seat for one end of a spring  62 , the other end of which embraces a flange  44  (FIG. 1) attached to the inner side of the blade carriage  16  so that the spring  62  biases the blade holder  60  away from the cable support  12 . As a consequence, the user applies a force overcoming the spring force and sufficient to guide the lever  28  along one of the side channels of the U-shaped recess  54  and extending beyond a flange  42  of the blade housing  40  exactly at the desired distance. The blade cap  100  is then screwed in on the blade housing  40  to lock the lever  28  between its inner surface and the opposing surface of the dial ring  56  and remains in this position during the cutting operation. The spring-biased structure of the blade holder allows the user to easily change the current cutting position of the blade  70  without detaching the cable stripper  10  from the cable by first releasing the blade cap  100  and then, by readjusting the thumb screw.  
     [0034] Another hole  50  (FIG. 4) can be tapped in the blade holder  60  at an angular distance from both holes  48  and  46  to provide a spiral cut, if needed. If a cable to be processed in not round, a wave spring  108  (FIG. 1) keeps the blade support in contact with this cable for constant blade penetration while the entire blade assembly is being adjusted.  
     [0035] An axial cut requires that forces applied by the user to the cable stripper be uniform and unidirectional. The handle  20  attached to the outer side of the cable support  12  and the blade cap  100  constitute the guide assembly meeting the requirement for the desired axial cut. The blade cap  100  is dimensioned to provide a sufficiently large surface allowing the user to have a comfortable grip by one of the user&#39;s hands, whereas the other hand can conveniently hold the handle  20 . To ensure the right distribution and direction of the pulling forces, the point of attachment of the handle  20  is located on a central axis  104  extending through the blade cap  100  and through the blade  70 . While different shapes of the handle can be successfully used, a ring-shape handle swingably attached to the cable support  12  is preferred.  
     [0036] While this disclosure has described various aspects of the present invention, the latter is not limited thereto, and is susceptible to numerous changes and modifications as known to those skilled in the art. Therefore, the invention is not limited to the details shown and described herein, and includes all such changes and modifications as are encompassed by the scope of the appended claims.