Patent Document

BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention concerns fuse cutout assemblies. More particularly, the invention is directed to an improved cutout assembly having means to aid in removal and replacement of a fuse tube. 
         [0003]    2. Description of the Prior Art 
         [0004]    Fuse cutout assemblies having removable fuse tubes have been in use for many years. The devices are generally characterized by the provision of an insulator mounted on a bracket having spaced contact assemblies. A lower contact assembly has a pair of spaced opposing trunnion sockets formed therein, while an upper contact assembly has a integral latching member, usually spring loaded. A fuseholder of the assembly has a lower end with opposing contact ears or trunnions that are adapted for insertion in journaled relation within the trunnion sockets. The upper end of the fuse tube has a latching contact end shaped for engagement with the upper contact assembly of the bracket. The fuseholder is thus removably positioned both physically and electrically in parallel with the insulator. 
         [0005]    Servicing these cutout assemblies, e.g., replacing the fuse, is generally accomplished by engaging the operating end of an extended hook stick within a pull ring provided proximate the upper contact assembly and corresponding latch. The worker then pulls down on the ring disengaging the latch and allowing the fuse tube to be accessed. Once the service/repairs are complete, the worker again engages the hook stick with the ring and rotates the fuseholder upwardly until the latch is engaged. A common problem encountered by utility company workers when servicing these cutout assemblies is that the fuse tube and its switch contact assemblies become disengaged from the bracket and fall to the ground putting the workers and equipment at risk. When the weather is inclement, as is typically the case, the risk of the fuse tube falling is particularly great. Also, servicing must be done at night or when visibility is otherwise low, causing great difficulty to the worker attempting to engage a relatively small ring with a hook stick from as much as 40 feet away. Regardless of how large the ring is made, the worker must still visually verify engagement of the hook stick therewith, and this can be an extremely time consuming operation. Furthermore, when replacing the fuseholder of the assembly, visual alignment of the fuseholder to ensure that the trunnions are properly positioned relative to the trunnion sockets is difficult, and improper alignment virtually guarantees that the fuseholder will fall, with the attendant risk of injury. Accordingly, many modifications have been made to the “standard” cutout assembly to reduce the risk of the fuseholder falling, both when engaging and disengaging the fuse tube. The modifications are typically fairly complex and are of limited effectiveness. Furthermore, most modifications that are considered “safety features” are often bypassed as they tend to make the service even more tedious, while only providing a limited safety factor. Finally, some manufacturers propose cutout assemblies radically different from standard assemblies, which have the drawback that technicians are totally unfamiliar with them and are unlikely to be proficient when servicing them. 
         [0006]    U.S. Pat. No. 5,670,927 issued to Fennell discloses a fuse holder with built in safety features. In lieu of a ring, the device has a slot within which the operation end of the hook stick may be placed to effect removal of the fuse tube. The problem with the Fennell device is that the slot is fashioned on the lower end of the fuse tube limiting the amount of torque that can be generated. Also, Fennell contemplates doing away with the ring entirely, not merely modifying it. 
         [0007]    U.S. Pat. No. 2,331,847 issued to Schultz discloses a fuse device having a pull ring with an enlarged, substantially right triangular shape. Also, Schultz discloses the provision of a pair of annular flanges to assist in positioning the trunnions within the trunnion sockets. Again, Schultz contemplates replacing and not modifying the traditional cutout assembly. Also, the flanges add additional bulk to the lower contact end of the assembly, possibly increasing the difficulty of replacing the fuse. 
         [0008]    The present invention is directed to a fuse cutout assembly having enhanced safety features to aid in both removal and replacement of fuse tubes. The inventive assembly can be produced by making modifications to standard fuse cutout assemblies. The modifications include lengthening the trunnions of the lower contact assembly and adding reflectors as a further visual aid for positioning the lower contact portion of the fuse tube within the trunnion sockets. Additionally, a molded plastic guide placed proximate the lower contact area of the fuseholder of the cutout promotes “self guiding” of the fuseholder during replacement. Also, the pull ring is modified by the addition of protruding arcuate sections extending from a standard pull ring, the sections allowing the technician to engage the pull down ring without aiming the hook stick through the ring. Additional reflectors are strategically placed to facilitate replacement of the fuseholder. 
       SUMMARY OF THE INVENTION 
       [0009]    It is a major object of the invention to provide a fuse cutout assembly with enhanced safety features. 
         [0010]    It is another object of the invention to provide a fuse cutout assembly with a self aligning feature to aid in replacing the fuse portion of the assembly. 
         [0011]    It is another object of the invention to provide a fuse cutout assembly with elongated trunnions. 
         [0012]    It is another object of the invention to provide a fuse cutout assembly with a modified pull ring which allows disengaging the fuse tube by guiding the hook stick along the length of the fuse tube. 
         [0013]    It is yet another object of the invention to provide a fuse cutout assembly which uses reflectors at selected positions for aligning the fuse tube during the replacement procedure. 
         [0014]    It is another object of the invention to provide a fuse cutout assembly having means to facilitate both removing and installing replacement fuses. 
         [0015]    Finally, it is a general goal of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is dependable and fully effective in accomplishing its intended purposes. 
         [0016]    These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
         [0017]    The present invention meets or exceeds all the above objects and goals. Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    Various other objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0019]      FIG. 1  shows a plan view of the fuse cutout assembly of the present invention. 
           [0020]      FIG. 2A  shows a front view of the guide member of the fuse cutout assembly. 
           [0021]      FIG. 2B  shows a side view, partly in section, of the guide member of  FIG. 2A . 
           [0022]      FIG. 2C  shows a rear view, partly in section, of the guide member of  FIG. 2A   
           [0023]      FIG. 3A  shows a plan view of the fuseholder of the assembly. 
           [0024]      FIG. 3B  is an isolated view of the pull ring portion of  FIG. 3A . 
           [0025]      FIG. 3C  is an isolated view of the spring loaded hinge and extended trunnion contacts of the fuseholder of the assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    Referring now to  FIGS. 1-3C  the fuse tube assembly of the present invention, generally indicated by the numeral  10 , is shown. It can be seen that the assembly  10  is of generally standard configuration having an elongated insulator  20  from which extend, at opposing ends, stationary contact members  22 ,  24 . The insulator  20  may be supported by a bracket  26  or the like, or by any suitable means. An upper contact assembly  27  having stationary and moving parts, the stationay part including a latching means  28  which is attached to and extends from the upper stationary contact member  22 , the latching means  28  essentially a terminal adapted for removable engagement with the electrically conductive portion of the upper end  30  of the fuseholder  32  of the assembly  10 , the upper end comprising the movable portion of the upper contact assembly. The latching means  28  is spring loaded and fashioned for automatically disengaging the upper end of the fuseholder  32  when the fuse melts as is well known. Any of several well known configurations may be used for this purpose, except as indicated below. Lower stationary contact member  24  is attached to lower contact assembly  35 , which includes means for supporting the lower end of the fuseholder  32  of the assembly. As is customary, a double hinge support for the lower end of the fuseholder  32  is provided, which includes trunnions  48 , formed of electrically conducting material, for engaging spaced jaws  49  so that the fuseholder  32  is initially mounted with the trunnions  48  arranged in the jaws  49  and is then rotated about the trunnions  48  to cause the upper end of the fuseholder  32  to become engaged with the latching means  28 . Thus, the fuseholder  32  of the assembly  10  is physically and electrically connected in parallel with insulator  20  via upper and lower contact assemblies  27 ,  35  which assemblies include the corresponding components of the fuseholder  32 . 
         [0027]    The fuseholder  32  of the assembly  10  includes an elongated fusible link  38  contained within a fiberglass fuse barrel  37 . The function of the fusible link  38  in cutout assemblies is well known and does not form a part of the present invention. A sleeve  39  attached to the upper end of the fuse barrel  37 , also known as a ferrule, includes a pull ring  40  which attaches to and extends outwardly from the sleeve  39  to provide both a target and a cooperating means for the engagement of the functional end of a hook stick (not shown), the hook stick allowing a lineman to access the fusible link  38  by pulling down on the pull ring  40  with the hook stick to effectuate temporary removal of the fuseholder  32  from the cutout assembly  10 . It can be seen that the ring  40  includes a pair of cooperating arcuate protrusions  44  and  46  which allow for a more facile engagement of the hook stick with the pull ring  40 . Another arcuate projection  47 , extending from the lower end of the fuseholder  32  allows for another tool to be employed for disengaging and removing the fuseholder  32 , as will be discussed in more detail later. 
         [0028]    When servicing fuse cutout assemblies there are two basic operations to be performed when replacing the fusible link  38  contained within the fuseholder  32 . The first is removal of the fuseholder  32  to gain access to the fusible link  38 , followed by replacement of the fuseholder  32  once a replacement fusible link  38  has been securely positioned. It can be appreciated that in order to ensure proper operation of the cutout assembly  10 , the fuseholder  32  must be properly positioned when replaced or it will fall from the assembly  10  with the attendant risks of injury as noted above. More particularly, great care must be taken to ensure that trunnions  48 , which form a part of the lower contact assembly  35  and extend from the lower end of the fuse portion  32  of the assembly, are properly seated in trunnion sockets  50  which essentially form a cradle within which the fuse portion is rotatably supported. Accordingly, many modifications made to cutout assemblies concern means for ensuring that the fuse portion  32  is properly seated so that it may be rotated upwardly to engage the upper contact assembly  27 . 
         [0029]    In one aspect of the present invention, trunnions  48  are extended laterally with respect to the fuseholder  32  to provide a larger visual target for alignment purposes. This visual aid, in accordance with a preferred embodiment, is further enhanced by the addition of reflectors  52  positioned on and secured to the forward facing portion of the outer surface of the trunnions  48 . The reflectors  52  may be formed of a reflective material coated onto a flexible substrate having an adhesive on the opposing side as is well known. Due to the configuration of the trunnions  48 , the reflectors are arranged in spaced relation so that the relative position and angle of the fuseholder  32  can be determined from a distance. Of course, any type of reflective material may be placed onto the trunnions  48  including hard plastic reflectors. The reflective material is preferably red or yellow or some non-metallic color so as to be easily distinguished from other metallic components of the assembly  10 , but any highly reflective material may be used. As the reflective material is not electrically conductive, it must not cover the entire trunnion so as to interfere with the electrical connection of the lower contact assembly  35 . The trunnions  48  are axially extended so that they protrude laterally from the outer edges of jaws  49  and trunnion sockets  50  at least an inch when placed therein so that the reflectors  52  provide a sufficiently large visual target, but any extension visually discernible from about  20  feet would be within the spirit and scope of the invention. Spring  51  coiled about shaft  53  connected between trunnions  58  is biased to urge the fuseholder  32  to the closed position as is well known. 
         [0030]    Attached to the lower contact assembly  35  by a bolt or any convenient means is a slide member  60  which acts as a guide to “funnel” the lower end of the fuse portion  32 , including trunnions  48  into position for re-closure of the cutout assembly  10 . The slide member  60  may be formed of a single piece of hard plastic or other non-conducting material. The slide member  60  may be attached to the stationary portion of the lower contact assembly  35  with the front end  66  of the slide  60  immediately adjacent trunnion sockets  50 . has a right triangular side profile as can be seen in  FIG. 2B , with an interior portion defined by a contoured inner surface  62 . The contoured surface  62  forms a channel  64 , and the slide member  60  is graduated from front  66  to rear  68  thereby forming opposing graduated surfaces  70  on opposite sides of the channel  64 . Of course, slide member may be formed with a single continuous graduated surface. The graduated surfaces  70  are sized and spaced in accordance with the size and spacing of the trunnions  48 , each surface  70  effectively acting as a ramp for one of the trunnions  48 . Thus, if the opposing trunnions  48  are placed anywhere along the respective inclined surfaces  70  during the replacement of the fuse portion  32 , the force of gravity will tend to urge or “funnel” trunnions  48  into position within trunnion sockets  50  assuring the fuseholder  32  is properly positioned. Rear wall  69  is flat and includes an indentation  71  corresponding to the position of the channel  64 . Reflectors  72 ,  74  positioned on bolts  76  cooperate with reflectors  52  to allow for proper centering and to ensure alignment as will be discussed below. Specifically, reflectors  72 ,  74  may be spaced to be slightly wider than the spacing of reflectors  52  to provide a centering target when repositioning the fuseholder  32 . The spacing of the reflectors  72 ,  74  is a function of the width of the slide member  60 , and the spacing and size of the reflectors  72 ,  74  should be chosen so that the reflectors  52  on trunnions  48  can be seen even when directly aligned with reflectors  72 ,  74 . The reflectors  72 ,  74  may be made of hard plastic and shaped for frictional fit over the entire bolt  76 . Reflectors  72 ,  74  must extend laterally from the slide member  60  so as to be viewable from the front of the assembly  10 . 
         [0031]    As has been previously mentioned, pull ring  40  is modified to include a pair of cooperating arcuate protrusions  44  and  46 . The protrusions  44 ,  46  are sized to allow for engagement of the hook stick without requiring insertion of the operating end of the stick within the eye  78  of the ring  40 . It can be seen that the ring  40  extends from a tab  80  with the lower inside portion of the tab having an arcuate indentation  82  extending roughly from the tab portion proximate the ring to the tip of the protrusion  44 . Protrusion  46  is also curved and is extended relative to protrusion  44  from ring  40  to provide a larger arcuate indentation  84 . An additional pull tab  47  is mounted onto the lower end of fuseholder  32  by a bolt or other means, the tab extending upwardly in an arched configuration and sized for engagement with a finger tool (not shown), which may optionally provide a means for removal of the fuseholder  32 . 
         [0032]    In operation, a lineman can disengage the fuseholder  32  of the cutout  10  by sliding the operating end of the hook stick up the fuse barrel  37  until it is engaged within indentation  82 , This procedure does not require visual verification as the hook stick will stop traveling up the fuse barrel  37  at the point when the operation end becomes seated within the indentation  82 . The lineman may then, totally by feel, slide the operating end down until it engages within indentation  84 , and proceed to disengage the fuse portion by pulling down with sufficient force to effect release of latching means  28 , which causes downward rotation of the fuseholder  32 , which may then be removed. Once a new fusible link  38  has been replaced within the fuseholder  32 , the lineman may then lower the fuse portion  32  until trunnions are seated within trunnion sockets  50 . This process is enabled by positioning the lower end of the fuseholder proximate to the slide member  60 , using reflectors  52 ,  72 , and  74  to ensure centering. Specifically, centering of the fuseholder  32  can be verified by determining the point at which reflectors  52  are aligned with reflectors  72  and  74 . Once visual verification of the centering is complete, the lineman may then allow the lower end of the fuseholder  32  to come to rest upon inclined surfaces  70 , still holding the fuse portion  32  by the hook stick until gravity causes the lower end of the fuse portion to slide down inclined surfaces  70  until trunnions  48  are properly seated within trunnion sockets  50 . The lineman may then slide the hook stick up the fuse barrel  37  until it is engaged within indentation  82 , again totally by feel, and rotate the fuseholder  32  upward until latching means  28  latches the top portion of the fuseholder  32 , returning the assembly to the operative position. In the event that the fusible link  38  melts, the spring loaded latch  28  is forced down thereby disengaging the latch  28  and causing the downward rotation of the fuseholder  32 . The fuseholder  32  may then be removed by positioning the operating end of a finger tool to engage arcuate pull tab  47  and then lifting the entire fuseholder  32  out. Once the fuse  38  has been replaced, the cutout  10  may be repositioned into the operative (closed) position as described above. 
         [0033]    From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. 
         [0034]    It is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims:

Technology Category: 5