Patent Publication Number: US-6655235-B2

Title: Fuse tool

Description:
TECHNICAL FIELD 
     The present invention relates generally to the field of tools and, in particular, to a tool that can be used to install and extract fuses. 
     BACKGROUND 
     Fuses are often difficult to extract or install without using a tool because of their location or because of the force required to perform the installation or extraction. For example, many of the environmentally protected housings used by the telecommunications industry are located on utility poles or suspended from cables and contain a multitude of fuses. Typically, these fuses are accessible through access ports that are often smaller than the average adult hand and are often located several inches from the plane of the access port. Moreover, the fuses often have exposed electrically charged surfaces and/or are often surrounded by electrically charged surfaces. 
     Frequently, tools that are made from electrical conducting materials, that apply incorrect forces to the fuse, or the like are used for installing or extracting fuses, e.g., “needle-nose” pliers, screwdrivers, or the like. Using tools made from electrically conducting materials frequently cause the user to receive electrical shocks, cause electrical shorts that often damage electrical equipment, or the like. Using tools that apply incorrect forces frequently damage the fuses or the equipment to which the fuses are coupled or do not enable the installation or extraction of the fuse. Moreover, many of the tools conventionally used for installing and extracting fuses often require the user to use both hands and/or to apply a continuous force to the tool to maintain engagement of the tool and fuse. This is undesirable and causes safety issues when changing fuses located in housings that are located on utility poles or suspended from cables. 
     For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for tools for installing or extracting fuses that reduce the user&#39;s risk for electrical shocks, reduce the risk of electrical shorts, can be operated with one hand, and do not require the user to apply a continuous force to maintain engagement between the tools and the fuses. 
     SUMMARY 
     The above-mentioned problems with the tools used to install and extract fuses and other problems are addressed by embodiments of the present invention and will be understood by reading and studying the following specification. Embodiments of the present invention provide tools for installing and extracting fuses that reduce the user&#39;s risk for electrical shocks, reduce the risk of electrical shorts, can be operated with one hand, and do not require the user to apply a continuous force to the tools to maintain engagement between the tools and the fuses. 
     More particularly, in one embodiment, a tool for installing and extracting a fuse is provided. The tool has a first bar that has a jaw at one end of the first bar. The tool has second bar that is slidably attached to the first bar and that has a jaw at one end of the second bar. The respective jaws are adapted to align by sliding the respective bars relative to each other to retain the fuse between the respective jaws. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of a first embodiment of the present invention. 
     FIG. 1 a  is the embodiment of FIG. 1 viewed along line  1   a — 1   a  of FIG.  1 . 
     FIG. 1 b  is the embodiment of FIG. 1 viewed along line  1   b — 1   b  of FIG. 1 a.    
     FIG. 2 a  is a top perspective-view of an embodiment of the present invention prior to insertion into a fuse protector-mount. 
     FIG. 2 b  is a bottom perspective-view of an embodiment of the present invention prior to insertion into a fuse protector-mount. 
     FIG. 2 c  is a front elevation view of an embodiment of the present invention prior to insertion into a fuse protector-mount. 
     FIG. 2 d  is a side elevation view of an embodiment of the present invention prior to insertion into a fuse protector-mount. 
     FIG. 3 a  is a top perspective-view of an embodiment of the present invention as inserted into a fuse protector-mount. 
     FIG. 3 b  is a side elevation view of an embodiment of the present invention as inserted into a fuse protector-mount. 
     FIG. 3 c  is a cross-sectional view of a jaw engaging a fuse as viewed from the back of FIG. 3 a.    
     FIG. 4 is a side elevation view showing the jaws of an embodiment of the present invention being aligned to retain a fuse. 
     FIG. 5 a  is a top perspective-view of an embodiment of the present invention as inserted into a fuse protector-mount and retaining a fuse. 
     FIG. 5 b  is a side elevation view of an embodiment of the present invention as inserted into a fuse protector-mount and retaining a fuse. 
     FIG. 6 a  is a top perspective-view of an embodiment of the present invention after extracting a fuse from a fuse protector-mount and retaining the fuse. 
     FIG. 6 b  is a bottom perspective-view of an embodiment of the present invention after extracting a fuse from a fuse protector-mount and retaining the fuse. 
     FIG. 6 c  is a side elevation view of an embodiment of the present invention after extracting a fuse from a fuse protector-mount and retaining the fuse. 
     FIG. 6 d  is a cross-sectional view of the jaws of an embodiment of the present invention retaining a fuse as viewed from the right of FIG. 6 c.    
     FIG. 7 is a side elevation view of an embodiment of the present invention releasing a fuse. 
     FIGS. 8 a  through  8   i  demonstrate an embodiment of a method of the present invention for installing a fuse in a fuse protector-mount. 
     FIG. 9 is an exploded view of a second embodiment of the present invention. 
     FIGS. 10 a  through  10   e  demonstrate a third embodiment of the present invention. 
     FIGS. 11 a  through  11   d  demonstrate a fourth embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific illustrative embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical and electrical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense. 
     Embodiments of the present invention provide tools for installing and extracting fuses that reduce the user&#39;s risk for electrical shocks, reduce the risk of electrical shorts, can be operated with one hand, and do not require the user to apply a continuous force to the tool to maintain engagement between the tool and the fuse. 
     A first embodiment of the present invention is exemplified by tool  100  in FIG. 1, an exploded view of tool  100 . Tool  100  includes bar  102  that has jaw  104  at end  105  of bar  102 . Tool  100  includes bar  106  that is slidably attached to bar  102  and that has jaw  108  at end  107  of bar  106 . Jaws  104  and  108  are adapted to align by sliding bars  102  and  106  relative to each other to retain fuse  110  between jaws  104  and  108 , as demonstrated in FIGS. 6 a-   6   c.  Jaws  104  and  108  are actuated out of alignment by sliding bars  102  and  106  relative to each other to remove fuse  110  from jaws  104  and  108  or to ready tool  100  for positioning fuse  110  between jaws  104  and  108  (see FIGS. 2 a ,  2   b ,  2   d ,  7 ,  8   a  and  8   i ). 
     Jaw  104  and bar  102  are integral and can be fabricated from any electrically nonconducting material having a suitable resiliency, such as glass-filled polycarbonate, glass-filled nylon, or the like. Likewise, jaw  108  and bar  106  are integral and can be fabricated from any electrically nonconducting material having a suitable resiliency, such as glass-filled polycarbonate, glass-filled nylon, or the like. 
     Fuse  110  is demonstrated in FIG. 2 b . Fuse  110  has central contact ring  110   a  that encircles and protrudes from the circumference of fuse  110  and a pair of contact rings  100   b  that encircle and protrude from the circumference of fuse  110  adjacent each of its ends. Contact rings  110   a  and  110   b  electrically couple fuse  110  to various electrical circuits. In some applications, fuse  110  has three electrical leads instead of three contact rings. Fuse  110  is placeable in protector-mount  112  (see FIGS. 2 b ,  2   c , and  2   d ). In one application, protector-mounts  112  are used to mount fuses  110  within environmentally protected housings, such as those used by the telecommunications industry. 
     Bar  106  is slidably attached to bar  102  by butting bars  106  and  102  together so that protrusions  116  of bar  106  extend into slots  118  of bar  102 , as shown in FIGS. 2 a ,  5   a , and  6   a . Slots  118  each have ends  118   a  and  118   b  that are opposite each other, as shown in FIGS. 1,  2   a ,  5   a , and  6   a . Slots  118  and protrusions  116  are respectively distributed along the lengths of bars  102  and  106  so that each protrusion  116  bears against end  118   a  of the corresponding slot  118  when jaws  104  and  108  are aligned (see FIG. 6 a ). The distance between ends  118   a  and  118   b  of each slot  118  is greater than the longitudinal extent of protrusions  116 , as seen in FIGS. 1,  2   a ,  5   a , and  6   a . This enables each of protrusions  116  to move between ends  118   a  and  118   b  of the corresponding slot, thus enabling bars  102  and  106  to slide relative to each other. Note that the distance between ends  118   a  and  118   b  determines the extent to which jaws  104  and  108  are actuated out of alignment by sliding bars  102  and  106  relative to each other. 
     Fasteners  120  are inserted into apertures  122  of protrusions  116 , as shown in FIG. 1, to maintain slidable contact between bars  102  and  106 , as shown in FIG. 2 a . In one embodiment, protrusions  116  and bar  106  are integral. In another embodiment, protrusions  116  are glued to bar  106 . Although the protrusions  116  shown in FIGS. 1 and  2   a  are rectangular blocks, they can be square blocks, cylinders, or the like. In one embodiment, fasteners  120  are pressed into apertures  122 . In another embodiment, fasteners  120  are threaded into apertures  122 . 
     Apertures  122  extend through protrusions  116  and through bar  106 , as shown in FIGS. 2 b  and  2   d . In another embodiment, apertures  122  terminate in bar  122 . In another embodiment, apertures  122  terminate in protrusions  116 . Although tool  100  is shown to have three protrusions  116  and three slots  118 , other embodiments have a single slot  118  and a single protrusion  116 , two slots  118  and two protrusions  116 , etc. In another embodiment bearings, e.g., roller, ball, or the like, are disposed between bars  102  and  106 . 
     Jaws  104  and  108  have arced profiles (see FIG. 1, FIGS. 2 a  and  2   d  and FIG. 6 c ) that have substantially the same radii. The radii of jaws  104  and  108  are substantially the same as the radius of fuse  110 . Jaws  104  and  108  are sufficiently resilient to accommodate variations in the fuse radius, such as variations due to manufacturing, e.g., fuse radii can vary slightly from manufacturer to manufacturer. As demonstrated in FIGS. 2 d  and  6   c , the arc length of jaw  104  is greater than that of jaw  108 . In one embodiment, the respective arc lengths are equal. In another embodiment, the arc length of jaw  104  is less than that of jaw  108 . 
     Jaw  108  is forked and includes a pair of tines  108   a  separated by slot  108   c  (see FIG.  1 ). Jaw  104  includes groove  104   a , as demonstrated in FIG. 1 a , FIG. 1 b , and FIG. 2 b , that extends along the length of jaw  104 . When fuse  110  is retained between jaws  104  and  108 , groove  104   a  receives a portion of central contact ring  110   a  and contact rings  110   b  straddle jaw  104 , as shown in FIG. 6 d . Moreover, tines  108   a  straddle central contact ring  110   a  and are respectively located between central contact ring  110   a  and one of contact rings  110   b.    
     Each of bars  102  and  106  has several gripping elements  124  that are perpendicular to the longitudinal axes of bars  102  and  106  (see FIG.  1 ). It will be appreciated by those of ordinary skill in the art that any arrangement of gripping elements  124  that facilitates gripping tool  100  can be used, e.g., gripping elements  124  can have various profiles, such as triangular, truncated triangles, semi-circular, etc., gripping elements  124  can be oriented at an angle relative to the longitudinal axes of bars  102  and  106 , or the like. 
     To extract a fuse  110  from protector-mount  112 , jaws  104  and  108  are actuated out of alignment, as shown in FIGS. 2 a ,  2   b , and  2   d , by sliding bars  102  and  106  relative to each other. Tool  100  is then inserted into protector-mount  112  so that the arc of jaw  104  engages a portion of the circumference of fuse  110 , as shown in FIGS. 3 a  and  3   b . In this position, groove  104   a  receives a portion of central contact ring  110   a  and contact rings  110   b  straddle jaw  104 , as shown in FIG. 3 c , a cross-sectional view of fuse  110  and jaw  104  as viewed from the back of FIG. 3 a.    
     Jaw  108  is then actuated into alignment with jaw  104  by sliding bar  106  relative to bar  102 . As jaw  108  contacts fuse  110 , as shown in FIG. 4, the resiliency of jaw  108  enables jaw  108  to be deflected by fuse  110 . Continued actuation of jaw  108  slides jaw  108  over the surface of fuse  110  in the circumferential direction until fuse  110  is retained between jaws  104  and  108 , as shown in FIGS. 5 a  and  5   b . Note that when the jaws are aligned, as shown in FIGS. 5 a ,  5   b ,  6   a  and  6   b , each protrusion  116  bears against end  118   a  of the corresponding slot  118 , as shown in FIGS. 5 a  and  6   a . Note further that when fuse  110  is retained between jaws  104  and  108 , groove  104   a  receives a portion of central contact ring  110   a , contact rings  110   b  straddle jaw  104 , and tines  108   a  straddle central contact ring  110   a  and are respectively located between central contact ring  110   a  and one of contact rings  110   b , as shown in FIG. 6 d.    
     Fuse  110  is extracted from protector-mount  112 , as shown in FIGS. 6 a - 6   c , by applying a generally longitudinal force to tool  100  that is directed away from protector-mount  112 . Fuse  110  is released from tool  100  by actuating jaws  104  and  108  out of alignment by sliding bars  102  and  106  relative to each other, as shown in FIG.  7 . During the initial portion of the actuation, jaw  108  slides over the surface of fuse  110  in the circumferential direction and is deflected away from fuse  110 . This is the reverse of that which occurs when the jaws are actuated into alignment, and the deflection of jaw  108  is similar to that demonstrated in FIG.  4 . 
     To install a fuse  110  in protector-mount  112 , jaws  104  and  108  are actuated out of alignment, as shown in FIG. 8 a , by sliding bars  102  and  106  relative to each other. Fuse  110  is positioned in jaw  104 , as shown in FIG. 8 b . In this position, groove  104   a  receives a portion of central contact ring  110   a  and contact rings  110   b  straddle jaw  104 , as shown in FIG. 8 c , a cross-sectional view of fuse  110  and jaw  104  as viewed from the right of FIG. 8 b.    
     Jaws  104  and  108  are then actuated into alignment by sliding bars  102  and  106  relative to each other. As jaw  108  contacts fuse  110 , as shown in FIG. 8 d , the resiliency of jaw  108  enables jaw  108  to be deflected by fuse  110 . Continued actuation slides jaw  108  over the surface of fuse  110  in the circumferential direction until fuse  110  is retained between jaws  104  and  108 , as shown in FIG. 8 e  and FIG. 8 f . FIG. 8 f  is a cross-sectional view of fuse  110  and jaws  104  and  108  as viewed from the right of FIG. 8 e . FIG. 8 f  demonstrates that groove  104   a  receives a portion of central contact ring  110   a , contact rings  110   b  straddle jaw  104 , and tines  108   a  straddle central contact ring  110   a  and are respectively located between central contact ring  110   a  and one of contact rings  110   b.    
     Fuse  110  is inserted into protector-mount  112 , as shown in FIG. 8 g , by applying a generally longitudinal force to tool  100  that is directed toward protector-mount  112 . Tool  100  is released from fuse  110  by actuating jaws  104  and  108  out of alignment by sliding bar  106  relative to bar  104 , as shown in FIG. 8 h . During the initial portion of the actuation, jaw  108  slides over the surface of fuse  110  in the circumferential direction and is deflected away from fuse  110 . This is the reverse of that which occurs when the jaws are actuated into alignment, and the deflection of jaw  108  is similar to that demonstrated in FIG. 8 d . Tool  100  is then removed from protector-mount  112 , as shown in FIG. 8 i.    
     A second embodiment of the present invention is exemplified by tool  900  in FIG. 9, an exploded view of tool  900 . Elements in FIG. 9 that are common to both FIGS. 1 and 9 are numbered as in FIG.  1  and are as described above. FIG. 9 shows that bar  102  of tool  900  has jaw  908  at end  905  in addition to jaw  104  at end  105  and that bar  106  of tool  900  has jaw  904  at end  907  in addition to jaw  108  at end  107 . 
     Jaw  908  is forked and includes a pair of tines  908   a  separated by slot  908   c . Jaw  904  includes groove  904   a  that extends along the length of jaw  904 . When fuse  110  is retained between jaws  904  and  908 , groove  904   a  receives a portion of central contact ring  110   a  and contact rings  110   b  straddle jaw  904 . Moreover, tines  908   a  straddle central contact ring  110   a  and are respectively located between central contact ring  110   a  and one of contact rings  110   b.    
     In one embodiment, the radii of jaws  904  and  908  are different than the radii of jaws  104  and  108 . This enables tool  900  to be used for fuses of two different diameters. 
     A third embodiment of the present invention is exemplified by tool  1000  in FIGS. 10 a  and  10   b . Elements in FIGS. 10 a  and  10   b  that are common to FIG.  1  and FIGS. 10 a  and  10   b  are numbered as in FIG.  1  and are as described above. FIG. 10 b  shows that bar  102  of tool  1000  includes blind hole  1002 , and FIGS. 10 a  and  10   b  show that bar  106  of tool  1000  includes slot  1004 . In another embodiment, bar  102  includes slot  1004 , and bar  106  includes blind hole  1002 . 
     Tool  1000  also includes ball plunger  1006 , as shown in FIGS. 10 a — 10   e  and available from M. J. Vail Company, Inc. and Jergens, Inc. Ball plunger  1006  includes housing  1008  containing ball  1012  that is biased by spring  1014  so that ball  1012  protrudes from housing  1008 , as shown in FIG. 10 c . Housing  1008  is secured in blind hole  1002  by pressing, threading, gluing, or the like. Ball  1012  rides in slot  1004  when bars  102  and  106  slide relative to each other. 
     FIGS. 10 d  and  10   e  are enlarged views respectively showing the position of ball  1012  when jaws  104  and  108  are aligned and are out of alignment. FIGS. 10 d  and  10   e  also show that slot  1004  includes recess  1004   a  and elevated portion  1004   b . When jaws  104  and  108  are aligned, ball  1012  extends into recess  1004   a  of slot  1004  and locks jaws  104  and  108  in the aligned position, as shown in FIG. 10 d . When jaws  104  and  108  are out of alignment, elevated portion  1004   b  of slot  1004  pushes ball  1012  into housing  1008 , compressing spring  1014 , as shown in FIG. 10 e.    
     A fourth embodiment of the present invention is exemplified by tool  1100  in FIGS. 11 a — 11   c . FIG. 11 a  is atop view of tool  1100 , and FIGS. 11 b  and  11   c  are side views, where FIG. 11 c  illustrates a feature for pivoting jaw  104 . Elements in FIGS. 11 a — 11   c  that are common to both FIG.  1  and FIGS. 11 a — 11   c  are numbered as in FIG.  1  and are as described above. Bar  102  of tool  1100  includes head  1102  that is pivotally attached to bar  102  by pin  1104 . Pin  1104  is perpendicular to the longitudinal axis of bar  102 , as shown in FIG. 11 a . Jaw  104  is located at end  1105  of head  1102 . Head  1102  pivots jaw  104  about pin  1104  when jaws  102  and  108  are out of alignment, as shown in FIG. 11 c.    
     Head  1102  includes protrusion  1106 . Protrusion  1106  has a T-shaped cross-section, as shown in FIG. 11 d , a cross-sectional view of protrusion  1106  as viewed from end  1105  of bar  102 . In another embodiment, protrusion  1106  has an L-shaped cross-section. Bar  106  includes slot  1108  that extends longitudinally from jaw  108 , as shown in FIGS. 11 b  and  11   c . In this embodiment, slot  1108  is a T-slot. In another embodiment, slot  1108  is an L-slot. 
     To bring jaws  104  and  108  into alignment from the non-aligned pivoted position shown in FIG. 11 c , head  1102  is pivoted into the position shown in FIG. 11 b . Then bars  102  and  106  are slid relative to each other to align jaws  104  and  108 . As  102  and  106  are slid relative to each other, protrusion  1106  is received by slot  1108  to prevent jaw  104  from pivoting while the jaws  104  and  108  are aligned. 
     Pivoting of jaw  104  enables tool  1100  to be used in tighter spaces than fuse tools without the pivoting provision. For example, when extracting a fuse  110  from a protector-mount  112 , jaws  104  and  108  are actuated out of alignment by sliding bars  102  and  106  relative to each other into the position shown in FIG. 11 b . Jaw  104  is then pivoted away from bar  106  to the position shown in FIG. 11 c . Jaw  104  is pivoted toward bar  106  to the position shown in FIG. 11 b  prior to aligning jaws  104  and  108  to retain a fuse  110  therebetween. After inserting a fuse  110  into a protector-mount  112 , tool  1100  is released from fuse  110  by actuating jaws  104  and  108  out of alignment by sliding bars  102  and  106  relative to each other into the position shown in FIG. 11 b . Jaw  104  is then pivoted away from bar  106  to the position shown in FIG. 11 c.    
     CONCLUSION 
     Embodiments of the present invention have been described. The embodiments provide tools for installing and extracting fuses that reduce the user&#39;s risk for electrical shocks, reduce the risk of electrical shorts, can be operated with one hand, and do not require the user to apply a continuous force to the tools to maintain engagement between the tools and the fuses. 
     Although specific embodiments have been illustrated and described in this specification, it will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. For example, the jaws can be modified to accommodate different types of fuses so that the tool is not limited to fuses of the type of fuse  110 . Specifically, the groove in jaw  104  can be removed or additional grooves can be added, or jaw  104  can be forked and have two or more tines. Moreover, jaw  108  can have more than two tines, or the tines replaced by a continuous jaw.