Patent Publication Number: US-6710697-B1

Title: Flexible cable operated fuse switch

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to fuse blocks generally, and in particular to a switching apparatus for selectively connecting and disconnecting a fuse block from its power source. 
     2. Discussion of the Related Art 
     Molded case fuse blocks are well known in the art for protecting electrical circuitry from damage due to power surges and the like. In particular, conventional fuse blocks are typically disposed within a cabinet to protect the associated electric circuitry from the external environment. In order to reduce the possibility of inadvertent contact with the live wiring inside the cabinet, it had become desirable to provide a system for automatically electrically disconnecting the fuse block from power when the cabinet door is opened. 
     For example, referring to FIG. 1, a cabinet  10  is provided having opposing upper and lower walls  12  and  14 , respectively, connecting at their left and right ends to opposing side walls  16 . The back end of the cabinet  10  is enclosed by a rear wall  18 , and at its front end by a door  20 . Door  20  is hingedly connected to one of the side walls  16 . A fuse block  22  is mounted to the inner surface of rear wall  18  such that fuses  24  are easily accessible to the user when door  20  is open. A series of electrical input leads  26  connect the fuse block  22  to a remote power source (not shown). A set of electrical output leads  28  extend through the lower wall  14  and connect the fuse block  22  to other circuitry. An operator  30  extends outwardly from fuse block  22  towards door  20 , and is rotatable about its axis of extension to electrically connect and disconnect fuses  24  from electrical input leads  26 . 
     Referring now also to FIG. 2, door  20  includes a door knob  32  that is configured to engage the rotatable operator  30 . In particular, a pair of cylindrical locking pins  34  extends horizontally outwardly from either side of the outer end  31  of rotatable operator  30 . A corresponding keyhole  36  is disposed in door knob  32 , and includes a first horizontally extending slot  38  sized to receive locking pins  34 . Key hole  36  further includes a second vertically extending slot  40  that intersects with slot  38  and is sized to receive the outer end  31  of rotational operator  30 . 
     During operation, when door  20  is closed, rotatable operator  30  and corresponding locking pins  34  are inserted into keyhole  36  of door knob  32 . Door knob  32  is subsequently rotated counterclockwise along the direction of arrow A, which further causes keyhole  36  to correspondingly rotate rotational operator  30  counterclockwise in the direction of arrow B to once again establish electrical connection between fuse block  22  and the power source. As door knob  32  is rotated in the direction of arrow A, a door latch (not shown) locks the door  20  in a closed position. Accordingly, in order to subsequently open the door  20 , door knob  32  is rotated clockwise to unlock the door  20  and automatically rotate operator  30  to disconnect the fuse block  22  with the power source. 
     A user is therefore advantageously unable to access the interior of cabinet  10  without first disconnecting the fuse block  22  from the power source via operator  30 . However, this system suffers from drawbacks related to both fabrication and use. For example, the fuse block  22  and door knob  32  must be precisely mounted in their proper location in order to ensure that keyhole  36  is in mating alignment with locking pins  34 . This is a difficult and sometimes tedious time consuming process. Additionally, when the door  20  is open, and fuse block  22  is disconnected from the power source, the user has the ability to manually rotate operator  30  in the direction of arrow B to reconnect the fuse block  22  and the power source while cabinet  10  is open. 
     What is therefore needed is a switching apparatus for a fuse block that avoids the manufacturing difficulties associated with conventional designs, and that limits a user&#39;s ability to inadvertently turn the fuse block on while the cabinet door is open. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with one aspect of the invention, a switching apparatus is provided for a fuse block that is disposed in a cabinet. The fuse block is of the type having at least one fuse operable to conduct current from a power source to a load and rotatable operator extending along an axis is operable to rotate about the axis between a closed and open position to correspondingly electrically connect and disconnect the fuse block with respect to the power source. The switching apparatus includes a handle mechanism that is mountable to a cabinet surface and movable between a first position and a second position. An actuating mechanism is provided having (A) a stationary member fixed relative to the fuse block; (B) a movable member movably connected to the stationary member; and (C) a linkage linked to the movable member and connected to the rotatable operator for rotating the rotatable operator in response to movement of the movable member. A cable assembly is attached to the handle at a first end and attached to the actuating mechanism at a second end opposite the first end. Movement of the handle mechanism from the first position to the second position causes the cable to translate the movable member with respect to the fuse block, thereby rotating the linkage and rotatable operator to electrically disconnect the fuse block from the power source. 
    
    
     The above aspects of the invention are not intended to define the scope of the invention for which purpose claims are provided. In the following description, reference is made to the accompanying drawings, which form a part hereof and in which there is shown by way of illustration, and not limitation, a preferred embodiment of the invention Such embodiment does not define the scope of the invention and reference must be made therefore to the claims for this purpose. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference is hereby made to the following figures in which like reference numerals correspond to like elements throughout, and in which: 
     FIG. 1 is a perspective view of a fuse block installed in a cabinet in accordance with conventional techniques; 
     FIG. 2 is a perspective view illustrating the interaction between the rotational operator and door knob of FIG. 1; 
     FIG. 3 is a perspective view of a fuse block and corresponding switch assembly constructed in accordance with the preferred embodiment of the present invention having sections cut away from the cabinet, the fuse block and switching assembly being in the “OFF” position; 
     FIG. 4 a  is a side elevation view of the actuating mechanism illustrated in FIG. 3 connected to the fuse block in a first “ON” position; 
     FIG. 4 b  is a side elevation view of the actuating mechanism illustrated in FIG. 4 a  but in a second “OFF” position; 
     FIG. 5 is a side elevation view illustrating the linkage of the actuating mechanism illustrated in FIGS. 4 a  and  4   b  being rotated from the “ON” position to the “OFF” position; 
     FIG. 6 is an exploded perspective view of the fuse block and switch assembly illustrated in FIG. 3 in the “ON” position; 
     FIG. 7 is a side elevation view of a handle portion of the handle mechanism illustrated in FIG. 3 in the “ON” position; and 
     FIG. 8 is a side elevation view of a mounting bracket of the handle mechanism illustrated in FIG. 3 in the “ON” position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 3, a fuse block  50  constructed in accordance with the preferred embodiment is mounted inside a cabinet  52  having upper and lower walls  54  and  56 , respectively, that are connected to opposing side walls  58  and  59 . A rear wall  60  is connected to the back ends of walls  54 ,  56 ,  58 , and  59 . A wall segment  62  extends vertically from upper wall  54  to lower wall  56  at the front of cabinet  52  proximal side wall  58 , and extends only partially towards the opposing side wall  59 . The remaining portion of the front end of cabinet  52  is occupied by a door  66  that is hingedly connected to side wall  59  and extends laterally such that outer edge  66  of door  66  connects to wall segment  62  by way of a latch  68  to enclose the cabinet  52  when door  66  is closed. 
     A switching assembly  86  includes a handle mechanism  166  that is mounted onto wall segment  62  in a vertical orientation. Handle mechanism includes a handle that is in mechanical communication with a cable assembly  144 . Referring now also to FIG. 6, an actuator  88  is linked to fuse block  50  and operable to electrically connect and disconnect the fuse block from its power source. Cable assembly  144  extends downstream from handle mechanism  166  and is connected to actuator  88 , such that handle  186  be manually actuated between an “ON” and “OFF” position to electrically connect and disconnect the fuse block  50  from the power source, as is described in more detail below. 
     Fuse block  50  is one of several types of conventional fuse blocks, such as is commercially available by Allen Bradley under Catalog No. 194R-NJ030P3 B. Fuse block  50  includes a fuse block housing  51  that is mounted onto a base plate  76 . Base plate  76  defines a front edge  77 , a rear edge  79 , a first lateral side edge  81 , and a second opposing lateral side edge (not shown). Base plate  76  is rectangular in cross-section, and defines a plurality of apertures  78  extending therethrough proximal each of its comers adjacent the intersection of its edges for mounting the fuse block  50  in cabinet  52 . For the purposes of this description, rear edge  79  is said to be disposed “downstream” of front edge  77  in the longitudinal direction, and side edge  81  is said to be disposed “laterally outwardly” with respect to fuse block housing  51 . 
     Fuse block housing  51  includes a top wall  70 , opposing front walls  72 , and opposing lateral side walls  74 . The bottom edges  73  and  75  of walls  72  and  74 , respectively, are connected to a base plate  76  via screws (not shown) or one of many alternative well-known fastening techniques. Upper wall  70  of fuse block defines three chambers  80  formed therein for receiving corresponding fuses that are electrically connected to an external electrical device that is disposed remotely with respect to cabinet  52 . In particular, a set of input leads  55  extends through rear wall  60 , and connects the remote power source to fuse block  50 . A set of output leads  57  extends through lower wall  56  and is connected to the external electrical device. A transparent cover  82  is mounted on to upper wall  70  and encases housings  80 . Cover  82  is mounted to upper wall  70  so as to be easily removable to allow access to fuses  80 . While fuse block  50  is three phase in accordance with the illustrated embodiment, it should be appreciated that any block housing a fuse for the purposes of controlling power between a power source and an electrical device is contemplated by the present invention. For example, fuse block  50  may include a single fuse or any number of fuses greater than one. 
     Base plate  76  is mounted onto the inner surface of rear wall  60  and configured such that upper wall  70  extends outwardly towards door  66  in accordance with the preferred embodiment. However, it should be appreciated that fuse block  50  may be mounted on any surface within the cabinet  52  such that sufficient clearance exists for the removal of cover  82 , and fuses  80  are accessible to a user performing maintenance operations. 
     A rotatable operator  84  is mounted to fuse block housing  51  and extends upwardly and adjacent side wall  74 . The base (not shown) of operator  84  is connected to a set of contacts that are in the path of current flow between the power source and fuses  80 . Operator  84  has a substantially square cross section and is rotatable to selectively close and open the contacts which, in turn, electrically engage and disengage fuses  80  with respect to the power source. While operator  84  has essentially a square cross section in accordance with the preferred embodiment, it should be appreciated that operator  84  may have a cross section of any shape that may be engaged by actuator  88  to rotate the operator  84 . During operation, operator is rotated counterclockwise along the direction of arrow C to open the set of contacts, thereby disconnecting the fuses  80  from the power source. Once operator  84  is in the “OFF” position, it may be rotated clockwise along the direction of arrow D to reengage the contacts and reestablish connection between fuses  80  and the power source. 
     Unlike conventional designs, operator  84  is not actuated by a door knob, and therefore does not span the entire depth of cabinet  52  through the entire transverse width of side wall  58 . Accordingly, fuse block housing  51  may be provided having a shortened operator  84  with respect to conventional designs. Advantageously, a conventional fuse block housing such as the type illustrated in FIG. I may alternatively be modified by the end user by cutting operator  30 , thereby shortening its length and rendering fuse block  22  compatible with the present invention. In this regard, it should be appreciated that the present invention provides a kit for the modification of preexisting fuse blocks. 
     The rotation of operator  84  is controlled by switching assembly  86 , which includes the actuator  88  having a stationary member  89  that is fixed with respect to the fuse block  50 , and a movable member  118  that is linked to the stationary member  89  and is operable to rotate operator  84  during use. In particular, stationary member  89  includes a bracket  90  disposed laterally outwardly and adjacent with respect to fuse block housing  51 . 
     Bracket  90  includes a horizontal base member  92  that extends downstream from a location proximal edge  77 . Base member  92  is mounted to base  76  via screws  94 , and is integrally connected to a vertical wall  96  extending upwardly from the laterally outer edge of base member  92 . Wall  96  defines opposing upwardly extending front and rear edges  98  (front edge shown) that terminate at a horizontal upper edge  100 . 
     A first rectangular vertical flange  102  extends laterally outwardly from the front edge  98  of vertical wall  96  proximal upper edge  100 . A rectangular second vertical flange  104  extends laterally outwardly from the rear edge of vertical wall  96  proximal upper edge  100 , such that first flange  102  is disposed upstream of second flange  104 . The combination of flanges  102  and  104  and vertical wall  96  defines a bracket  106  that extends in the direction of extension of cable assembly  144 . Each flange  102  and  104  defines corresponding circular apertures  108  and  109  extending horizontally there through, respectively, that are laterally and vertically aligned with each other. 
     Stationary member  89  further includes a third rectangular flange  110  that extends laterally outwardly from wall  96  in a horizontal orientation at a location upstream of flange  104  and has a bottom surface  113 . A vertically extending circular aperture  112  extends through the laterally outer end of flange  110 . A fourth rectangular flange  114  extends laterally outwardly from wall  96  in a vertical orientation, and is disposed downstream of brackets  102 , and upstream of bracket  110 . A laterally elongated horizontal slot  116  extends through bracket  114  at a location below the bottom surface  113  of flange  110 . 
     Movable member  118  includes a horizontal base  120  that is elongated in the longitudinal direction. Base  120  terminates at a downstream end  121  that is substantially vertically aligned with rear edge  79  of base  76 . Downstream end  121  is integrally connected to a rectangular vertical flange  122  extending upwardly from end  121 . Flange  122  defines a substantially circular aperture  124  extending horizontally therethrough such that aperture  124  is generally aligned with apertures  108  and  109  of stationary member  89 . Base  120  terminates at its upstream end at a tongue  123  that extends upstream through slot  116 . 
     Movable member  118  further includes a rectangular horizontal flange  140  extending laterally outwardly from the base  120  at a position downstream of flange  110  when operator  84  is in the “ON” position, and upstream of flange  122 . A substantially circular aperture  142  extends vertically through flange  140 , and is in longitudinal and lateral alignment with aperture  112  extending through flange  110 . The combination of flanges  110  and  140  define a locking mechanism when actuator  88  is in the “OFF” position, as will be described in more detail below. 
     Referring now also to FIG. 4A, movable member  118  further includes a pair of rectangular upper and lower horizontal flanges  126  that are attached to the upper and lower surface of base  120 , respectively. Flanges  126  extend laterally inwardly from base  120 , and define a vertical gap there between. Flanges  126  are joined approximately at their midpoint via a pin  128  that extends there between. 
     A horizontal arm  130  includes an inner mounting member  132  integrally connected to an outer engagement member  134 . Inner mounting member defines an elongated oval-shaped slot  136  extending there through having a corresponding oval,shaped outer wall  133 . Slot  136  is sized to receive pin  128  therein so as to be rotatable and translatable with respect to the pin  128 . Outer engagement member  134  defines a substantially circular outer wall  135  having an aperture  138  extending vertically there through that has a substantially square cross section sized to receive rotatable operator  84  therein In this regard, it should be appreciated that aperture  138  may be of any size and shape so as to engagingly receive operator  84 . For instance, operator  84  and aperture  138  may have any noncircular cross-section such that the edges that define aperture  138  engage the outer edges of operator  84  such that rotation of engagement member  134  correspondingly rotates operator  84 . Alternatively, operator  84  may have a circular cross-section that may be engaged by engagement member  134  via a locking pin or alternative mechanism as is appreciated by one having ordinary skill in the art. Arm  130  thus provides a linkage between movable member  118  and rotatable operator  84 . 
     Referring now also to FIGS. 4 b  and  5 , when movable member  118  is translated from its downstream “ON” position to its upstream “OFF” position along the direction of arrow F, the upstream movement of pin  128  causes linkage  130  to translate and rotate with respect to pin  128 . The movement of mounting member  132  causes outer engagement member  134  to pivot in the counterclockwise direction about aperture  138 . Because rotatable operator  84  extends through aperture  138  and is rotatably fixed thereto, the rotation of member  134  causes linkage  130  to correspondingly rotate operator  84  in the counterclockwise direction of arrow C to disconnect fuse block  50  from its power source. Correspondingly, downstream movement of movable member causes aperture  138  to rotate clockwise, thereby correspondingly rotating operator clockwise in the direction of Arrow D to reconnect fuse block with the power source. 
     Advantageously, when the actuator  88  is configured to disconnect the fuse block from the power source, base  120  is translated to its upstream position as tongue  123  travels upstream through slot  116 . As base  120  translates upstream, flange  140  is brought into vertical alignment with flange  110 , such that corresponding apertures  142  and  112  are aligned when the actuator is in its full upstream position. A user is thus advantageously able to lock fuse block  50  in its off position by inserting a padlock or the like through apertures  112  and  142  to prevent electricity from flowing through fuse block  50  while cabinet door  66  is open. In order to reconnect the fuse block  50  to its power source, the maintenance personnel will first have to remove the lock before movable member  118  may once again travel downstream. 
     Referring now to FIGS. 3 and 7, handle mechanism  166  includes an outer housing block  168  having a front wall  170  that is configured to be mounted to the outer surface of wall section  62  of cabinet  52  in a vertical orientation. Housing block  168  further includes an upper wall  172  and lower wall  174  that are connected to side walls  176 . A rear wall  178  is connected to the outer edges of walls  172 ,  174 , and  176 . A pair of handle arms  180  is connected to side walls  176  via a pin  182  that extends laterally through housing block  168 . Handle arms  182  are joined at their distal end  184  to provide a handle  186  having sufficient clearance with reselect to rear wall  178  of housing block  168  during operation Handle  186  is rotatable downwardly in the direction of Arrow G from its upper “ON” position illustrated in FIG. 7 to its lower “OFF” position illustrated in FIG. 3, and vice versa 
     Housing block  168  further includes a linkage arm  188  having a neck  190  that extends outwardly and slightly downwardly from wall  170  and terminates at a connector  192 . Neck  190  extends into housing block  168 , and is in mechanical communication with handle  186  by one of many well known techniques in the art. Connector  192  defines a mounting location  194  in the form of an aperture extending there through. Housing block  168  further includes a locking arm  196  having a neck  198  that extends outwardly from wall  170 , and is also linked to movement of handle  186 . Neck  198  terminates at a connector  200  having a pair of connection locations  202  in the form of apertures extending there through. It should thus be appreciated that wall portion  62  includes openings formed therein (not shown) to accommodate linkage arm  188  and locking arm  196  that extend into the interior of cabinet  52 . 
     When handle  186  is rotated to the “OFF” position, locking arm  196  becomes engaged and prevents handle  186  from being rotated to the “ON” position until arm  196  is released. Locking arm  196  may be depressed manually to unlock the handle  186 , or released automatically upon shutting the door  66  and locking the door latch  68 . In particular, connection locations  202  of locking arm  196  are placed in mechanical communication with door latch  68 , such that when the door is closed, activating latch  68  depresses locking arm  196 , which enables handle  186  to be rotated to its “ON” position. Furthermore, once the handle  186  is in the “ON” position, locking arm  196  translates upwardly to prevent a user from opening latch  68  until the handle  186  is rotated to the “OFF” position. 
     Referring now also to FIG. 8, handle mechanism  166  further includes a mounting bracket  204  having a lower beam  206  connected at one end to a front wall  208 , and connected at its other end to a rear wall  210 . Front wall  208  is defined herein to be disposed “inwardly” with respect to rear wall  210 . Front wall  208  is configured to be mounted to the inner surface of wall section  62 , and includes a pair of upper and lower vertically extending notches  216  and  218 , respectively, that are configured to receive necks  190  and  198  of linkage arm  188  and locking arm  196 , respectively. 
     Walls  208  and  210  are connected to one of a pair of upper beams  212  (one shown) that are spaced apart from each other at their front end by the thickness of wall  208  at its front end, and spaced apart from each other at their rear end by a pin  214  extending there through. A swivel arm  220  has a proximal end  222  that is pivotally connected to pin  214 . Arm  220  has a first distal end  224  extending inwardly and slightly downwardly from proximal end  222  that has a connection location  226  in the form of an aperture extending there through. A horizontal bracket  228  extends across lower beam  206  at a position in substantial vertical alignment with connection location  226 . Arm  220  further includes a second distal end  230  extending downwardly and slightly inwardly from proximal end  222  that has a connection location  232  in the form of an aperture. Connection  232  is configured to connect to connection  194  via a locking pin or the like to rotatably connect linkage arm  188  to swivel arm  220 . 
     Referring now to FIGS. 3,  4 A.  4 B, and  6 , the cable assembly  144  includes a tubular metal cable member  146  that is surrounded by a stiff rubber or plastic tubular outer sleeve  148 . Outer sleeve  148  defines a proximal end  158  that extends through bracket  228  which is subsequently tightened to affix the proximal end  158  of the outer sleeve  148  to the mounting bracket  204  of handle mechanism  166 . Outer sleeve  148  defines a distal end  156  that is fastened to flange  102  of stationary member  89  via a mounting sleeve  160  that surrounds sleeve  148  at its distal end. Sleeve  160  extends through aperture  108  and is threaded to support a pair of locking nuts  164  that are tightened on either side of flange  102 . Cable  146  defines a distal end  150  that extends downstream of the distal end of sleeve  148 . Distal end  150  of cable  146  has a threaded portion that extends through aperture  124  and connected to flange  122  of movable member  118  by a pair of locking nuts  152  that are tightened on either side of flange  118 . Cable  146  further defines a proximal end  154  that extends upstream beyond the proximal end of outer sleeve  148 . Proximal end  154  of cable  146  is fastened to connection location  226  of first distal end  224  of swivel arm  220  via a pin or the like. 
     The operation of switching assembly  86  will now be described with reference to FIGS. 3,  6 ,  7 , and  8 . In particular, when the handle  186  is in the “ON” position as illustrated in FIG. 7, the linkage arm  188  is extended. Arm  188  biases distal end  230  of swivel arm  220  outwardly, causing arm  220  to pivot counterclockwise about pin  214 , which in turn causes mounting location  226  of distal end  224  to translate downwardly. Swivel arm  220  thus biases cable  146  downstream, which in turn biases movable member  118  downstream. As described above with reference to FIGS. 4A,  4 B, and  5 , the downstream movement of flange  126  causes linkage  130  to pivot clockwise about aperture  138 . The rotation of aperture  138  causes operator  84  to rotate clockwise, thereby connecting fuse block  50  to the power source. 
     When handle  186  is rotated downwardly to its “OFF” position illustrated in FIG. 3, linkage arm  188  is retracted along the direction indicated by arrow E which, in turn, rotates swivel arm  220  clockwise about pin  214 . Clockwise rotation causes mounting location  226  of distal end  224  to translate upwardly. Swivel arm  220  thus biases cable  146  upstream, which in turn biases movable member  118  upstream. As described above with reference to FIGS. 4A,  4 B, and  5 , the upstream movement of flange  126  causes linkage  130  to pivot counterclockwise about aperture  138 . The rotation of aperture  138  causes operator  84  to rotate counterclockwise, thereby disconnecting fuse block  50  to the power source. 
     Advantageously, the locking arm is linked to the linkage arm in the housing block  168  (not shown) such that once handle  186  has been rotated to the “OFF” position, handle arm remains locked in the off position until the cabinet door  66  is closed and latch  68  activated to release the locking arm  196 , or until a user manually unlocks locking arm  196 . 
     The above has been described as a preferred embodiment of the present invention It will occur to those that practice the art that many modifications may be made without departing from the spirit and scope of the invention. For example, while stationary member  89  is affixed to the base  76  of fuse block  50 , it should be appreciated that member  89  could be disposed anywhere within cabinet  52  such that its position is fixed with respect to fuse block  50  to enable movable member  118  to rotate operator  84 . In order to apprise the public of the various embodiments that may fall within the scope of the invention, the following claims are made.