Abstract:
A fuse block having a rotary operator communicating with a door-mounted knob provides a handle on the rotary operator for engaging the door handle to detect closure of the door. The handle includes first and second coupling mechanisms that control the connection between the handle and the operator depending on whether the door is open or closed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a Continuation-In-Part of U.S. patent application Ser. No. 10/298,326, filed Nov. 18, 2002, the disclosure of which is hereby incorporated by reference as if set forth in its entirety herein. 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to electrical fuse blocks for mounting in cabinets and having a forwardly-extending, rotary disconnect operator that may engage a handle on the cabinet door when the cabinet door is closed, and in particular to an improvement in such a fuse block that reduces the chance of accidental operation of the disconnect operator when the cabinet door is open.  
           [0003]    Referring to FIG. 1, a standard fuse block  10  of the prior art may receive fuse cartridges  12  along its front face and may attach at its rear face to the rear wall  14  of a metal cabinet  16 .  
           [0004]    Input terminals along the top of fuse block  10  may receive wires  18  which connect independently to one side of each fuse cartridge  12 , the latter which interconnect wires  18  to wires  20  attached to output terminals along the bottom of the fuse cartridge  12 . Wires  18 , for example, may be connected to a source of three-phase power and wires  20 , for example, may be connected to a motor or other piece of equipment.  
           [0005]    Fuse block  10  may incorporate a disconnect mechanism (not shown) serving to electrically disconnect wires  18  from the respective fuse cartridges  12 . The disconnect mechanism may be controlled by a rotary operator  22  along one side of the fuse block  12  and extending in an orientation perpendicular to the rear wall  14  of cabinet  16  toward an open face of the cabinet.  
           [0006]    The open face of the cabinet may be covered by a door  24  attached by hinges to one side of the cabinet  16 . Door  24  may support a captively mounted rotary knob  26  having an inwardly extending connector  28 .  
           [0007]    Referring now to FIG. 2, knob  26  may include connector  28  that extends inwardly through an opening in the door  24 . Connector  28  includes retaining flanges  30  for retaining it rotatably within that opening.  
           [0008]    When door  24  is closed about the cabinet  16 , connector  28  of the knob  26  may engage the outermost end of rotary operator  22 , thereby allowing the rotary operator to be operated by knob  26  when door  24  is closed on cabinet  16 . Specifically, an inwardly facing end of connector  28  may include a keyway  32  receiving a rectangular end of rotary operator  22  and a pin  34  extending perpendicularly through the rotary operator. Turning knob  26 , in turn, rotates operator  22  to electrically disconnect or connect power to wires  20 .  
           [0009]    Referring again to FIG. 1, knob  26  allows disconnection of power to wires  20  when the door  24  on the cabinet  16  is closed. However, when door  24  is open, rotary operator  22  is exposed, thereby enabling power to be inadvertently reconnected by counter rotation the operator  22 .  
           [0010]    One apparatus for preventing the reconnection of power while the door is open includes bracketing that is connected to the exterior of fuse block  10 . The bracketing enables knob rotation to connect and disconnect the power when the door is closed, and further prevents inadvertent counter rotation of the knob to reconnect the power when the door is open. While this apparatus is suitable for its intended purpose, the bracketing requires modification of an existing fuse block.  
           [0011]    It would therefore be desirable to provide a less intrusive mechanism for preventing rotation of the operator in a direction that would reconnected power when the cabinet door is open.  
         BRIEF SUMMARY OF THE INVENTION  
         [0012]    The present invention provides a handle having an integral coupling mechanism that senses the position of the door of the cabinet and lock its disconnect in the open position to prevent inadvertent connection of power when the cabinet door is open. The locking of the disconnect may be overridden when it becomes desirable to reconnect power when the cabinet door is open.  
           [0013]    In accordance with one aspect of the invention, a disconnect mechanism is provided for a fuse block receiving power connections and of a type having a support face for mounting on a panel with one or more fuse sockets accessible on a front face of the fuse block opposite the support face. A rotary operator extends outwardly and defines an outer end that is adapted to receive a portion of a door-mounted knob. The operator rotates in a first direction to connect the fuses with the power connections, and rotates in a second direction to disconnect the fuses from the power connections.  
           [0014]    The disconnect mechanism includes a rotating handle that receives the outer end of the rotary operator. The handle includes a housing, and a first coupling mechanism that is releasably connected between the operator and the housing. The first coupling mechanism rotates the operator in the first and second directions in response to rotation of the handle in the first and second directions. A second coupling mechanism is connected between the operator and the handle, and includes an engagement member that rotates the operator in the second direction when the handle is rotated in the second direction. The unidirectional engagement member does not rotate the operator when the handle is rotated in the first direction.  
           [0015]    The foregoing and other advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part thereof, and in which there is shown by way of illustration, and not limitation, preferred embodiments of the invention. Such embodiments do not necessarily represent the full scope of the invention, and reference should therefore be made to the claims herein for interpreting the scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a perspective view of a prior art fuse block described above and mounted to the rear of a cabinet and having a forwardly extending rotary disconnect operator that may be received by a door-mounted handle when the cabinet door is closed;  
         [0017]    [0017]FIG. 2 is a fragmentary view of the door-mounted handle immediately before engagement with the rotary disconnect operator as known in the prior art;  
         [0018]    [0018]FIG. 3 is a perspective view of a fuse block mounted to the rear of a cabinet and having a forwardly extending rotary disconnect operator extending through a handle constructed in accordance with the preferred embodiment;  
         [0019]    [0019]FIG. 4 is a perspective view of the handle illustrated in FIG. 3 receiving the operator;  
         [0020]    [0020]FIG. 5 is an assembly view of the handle illustrated in FIG. 3  
         [0021]    [0021]FIG. 6 is an assembly view of a ratchet assembly included in the handle illustrated in FIG. 5;  
         [0022]    [0022]FIG. 7 is a top plan view of the handle illustrated in FIG. 3;  
         [0023]    [0023]FIG. 8 is a bottom view of the handle illustrated in FIG. 3;  
         [0024]    [0024]FIG. 9 is a top plan view of a plate forming part of the ratchet assembly illustrated in FIG. 6;  
         [0025]    [0025]FIG. 10 is a top plan view of a sprocket forming part of the ratchet assembly illustrated in FIG. 6;  
         [0026]    [0026]FIG. 11 is a side elevation view of the handle illustrated in FIG. 3 when the door is open;  
         [0027]    [0027]FIG. 12 is a side elevation view of the handle illustrated in FIG. 3 when the door is closed;  
         [0028]    [0028]FIG. 13 is a sectional side elevation view of the handle illustrated in FIG. 11;  
         [0029]    [0029]FIG. 14 is a sectional side elevation view of the handle illustrated in FIG. 12;  
         [0030]    [0030]FIG. 15 is a sectional top elevation view of the ratchet assembly illustrated in FIG. 13 taken along line  15 - 15 ;  
         [0031]    [0031]FIG. 16 is a sectional top elevation view of the ratchet assembly similar to FIG. 15, wherein the sprocket is rotated clockwise;  
         [0032]    [0032]FIG. 17 is a top plan view of the ratchet assembly illustrated in FIG. 6;  
         [0033]    [0033]FIG. 18 is a side elevation view of the ratchet assembly illustrated in FIG. 17 taken along line  18 - 18  in an engaged position;  
         [0034]    [0034]FIG. 19 is an enlarged view of the ratchet assembly taken along line  19 - 19  of FIG. 18;  
         [0035]    [0035]FIG. 20 is a view of the ratchet assembly similar to FIG. 19, but with the assembly in a disengaged position;  
         [0036]    [0036]FIG. 21 is a sectional side elevation view of the handle when the door is open after a user has manually activated the primary coupling mechanism;  
         [0037]    [0037]FIG. 22 is a sectional side elevation view of the primary coupling mechanism; and  
         [0038]    [0038]FIG. 23 is a partial sectional elevation view of the handle illustrated in FIG. 21. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0039]    Referring now to FIGS. 3 and 4, the present invention modifies the fuse block  10  described above by mounting a handle  36  onto the axially outer end of rotary operator  22  such that the handle interfaces with the door knob  26 , and in particular with connector  28 . Handle preferably comprises a plastic, though one skilled in the art will recognize that any material suitable to withstand the stress and strain experienced during operation falls within the scope of the present invention.  
         [0040]    Handle  36  includes a housing assembly  41  including an inner housing  38  that is interlocked with an outer housing  40 . A flange  42  extends radially outwardly from the axially outer end of housing  40  whose radially outer surface defines a plurality of grooves  43  that are configured to be gripped by a user&#39;s hand to facilitate rotation of housing assembly  41  in the clockwise and counterclockwise directions. In accordance with the preferred embodiment, when power is connected, rotation of handle  36  (and operator  22 ) in the counterclockwise direction disconnects power in fuse block  10 . When power is disconnected, rotation of handle  36  (and operator  22 ) in the clockwise direction reconnects power in the fuse block. It should be appreciated, however, that these directions of rotation can be reversed in accordance with the preferred embodiment to connect and disconnect the power.  
         [0041]    Referring also to FIG. 7, handle  36  further includes an inner hub  44  that is radially surrounded by outer housing  40 . Hub  44  further includes an outer face  46  that defines a keyway  47 . Keyway  47  receives pin  34  of operator  22 , which extends through hub  44  such that the operator  22  and hub  44  can rotate in concert. Inner hub  44  is spring-loaded and can thus be depressed with respect to outer housing  40  and connector  22  when door  24  is closed.  
         [0042]    As a result, when door  24  is closed, connector  28  depresses hub  44  relative to operator  22 , causing the outer end of operator  22  (including pin  34 ) to be disposed outwardly from outer face  46 . Pin is thus received by keyway  32 . Handle  36  includes a primary coupling mechanism that enables operator  22  to rotate clockwise and counterclockwise along with knob  26  to connect and disconnect power in fuse block  10 , respectively. Handle  36  further includes a secondary coupling mechanism that enables power to be disconnected by rotating handle  36  counterclockwise in the manner described above when door  24  is open and hub  44  is not depressed. In order to reconnect power when door  24  is open, flange  43 , a user can pull housing assembly  41  axially outwardly (or depress hub  44  inwardly) in order to rotate handle  36  clockwise. If housing assembly  41  is not first pulled relative to hub  44 , housing assembly  41  will rotate freely in the clockwise direction without rotating hub  44  and operator  22 . The secondary coupling mechanism thus prevents power from being inadvertenly reconnected by rotating handle  36  clockwise when door  24  is open. The primary and secondary coupling mechanisms will now be described.  
         [0043]    Referring now to FIG. 5, outer housing  40  includes outer flange  42  and an annular neck  48  extending axially inwardly from flange  42 . An inner flange  35  extends radially inwardly from neck  48 . A pair of threaded apertures  45  extend inwardly from flange  42 . Apertures  45  are formed in the radially outer surface of flange  42 , and are disposed at radially opposite locations on flange  42 . Apertures  45  are sized to receive corresponding screws  54 . A plurality of radially spaced notches  49  extends axially inwardly from the inner end of neck  48 , and are equally spaced circumferentially about neck  48  such that a corresponding plurality of recesses  51  are interposed between adjacent notches  49 .  
         [0044]    Hub  44  includes a generally annular body  50  having an outer diameter sized to fit within annular neck  48 . A plurality of projections  52  extend radially outwardly from the inner end of body  50 . Projections  52  do not extend to outer face  46 , and are equally spaced circumferentially about body  50  such that a corresponding plurality of recesses  53  are interposed between adjacent projections. A centrally disposed cylindrical hub  63  (see FIG. 13) extends inwardly from outer face  46 , and defines an outer diameter that is slightly less than the inner diameter of a coil spring  39 . Spring  39  thus fits over hub  63  and abuts the inner surface of outer face  46 . Spring  39  is in compression during operation, and thus configured to bias hub  44  axially outwardly towards outer housing  40 .  
         [0045]    The outer ends of projections  52  abut the inner end of flange  35  to provide a stop when hub  44  is biased to its outer (non-depressed) position by spring  39 . Specifically, flange  35  and outer ends of projections  52  enable rotation of outer housing  40  relative to hub  44 .  
         [0046]    An aperture  65  extends axially through hub  63 , and defines a square cross-section configured to snugly receive operator  22  such that rotation of hub  44  causes operator  22  to also rotate. It should be easily appreciated, however, that operator  22  and aperture  65  could assume cross-sectional shape without departing from the present invention.  
         [0047]    Referring now also to FIG. 8, inner housing  38  includes an annular body  56  closed at its axially inner end by a radial inner face  58 . An aperture  55  extends axially through inner face  58 , and is centrally disposed to receive operator  22 . Aperture  55  is greater than the cross-sectional area of operator  22  such that rotation of inner housing  38  does not directly cause operator  22  to rotate, as will be described in more detail below. A pair of opposing flanges  57  extends radially outwardly from body  56 , and includes a pair of apertures that are aligned with apertures  45  of outer housing  40 . A plurality of radially spaced notches  59  extends outwardly from the outer end of body  56 , and are equally spaced circumferentially about body  56  such that a corresponding plurality of recesses  61  are interposed between adjacent notches. Notches  59  and recesses  61  of inner housing  38  are configured to interlock with recesses  51  and notches  49 , respectively, of housing  40 .  
         [0048]    The outer end of housing  38  is open and can receive hub  44  when hub  44  is depressed, either manually or via connector  28  when door  24  is closed. Specifically, a plurality of axially extending ribs  60  protrudes from the radially inner surface of body  56 , and are equally spaced circumferentially about body  56  such that a corresponding plurality of recesses  62  are interposed between adjacent ribs  60 . The diameter defined by opposing recesses  62  is slightly greater than the diameter defined by opposing projections  52 , and the diameter defined by opposing ribs  60  is slightly greater than the diameter defined by opposing recesses  53 .  
         [0049]    Accordingly, when hub  44  is received by inner housing  38 , ribs  60  and recesses  62  interlock with recesses  53  and projections  52 , respectively, thereby causing hub  44  and inner housing  38  (and thus housing assembly  41 ) to rotate together. As a result, the interlock between hub  44  and inner housing  38  provides a primary coupling mechanism that causes hub  44  and operator  22  to rotate together in both the clockwise and counterclockwise directions. When hub  44  is not depressed and projections  52  and ribs  60  are not interlocked, the primary coupling mechanism is disengaged.  
         [0050]    Referring now also to FIGS. 6, 9, and  10 , handle  36  includes a ratchet assembly  64 , which includes a sprocket  66  and a circular disc  68 . Sprocket  66  and disc  68  are preferably formed from a metal or could alternatively be formed from a plastic or any alternative material suitable to endure the stress and strain experienced during operation. Sprocket  66  is defined by generally rectangular teeth  70  that extend from a generally flat circular base  71 . Teeth  70  are configured to fit into recesses  62  and engage ribs  60  of inner housing  38  such that rotation of inner housing  38  causes sprocket  66  to rotate. Sprocket  66  rests against the outer surface of inner face  58  when installed in housing  38 . The axially inner ends of ribs  60  can be slightly thicker than the remaining portion of ribs  60 , to provide reinforcement due to the stresses experienced during operation, while still being sufficiently sized to fully receive sprocket  66 . A generally circular aperture  72  extends axially through sprocket  66 , and is centrally disposed to receive operator  22 . Aperture  72  is sized greater than the cross-section of operator  22  such that relative rotation is permitted between sprocket  66  and operator  22 .  
         [0051]    A plurality of apertures  74  extends through base  71 , and are equally spaced radially about aperture  72 . Each aperture  74  defines a radially extending leading edge  76  and a trailing edge  78  when sprocket  66  is rotated in the counterclockwise direction. A generally rectangular tooth  80  defines a base  82  that is connected to each trailing edge  78 . Teeth  80  extends radially outwardly from the base  82  towards the opposing leading edge  76 , and curve axially outwardly toward a distal engaging surface  84 . The axially outer surface of each tooth  80  defines a cam surface  86  for disc  68 , as will now be described.  
         [0052]    In particular, disc  68  includes a plurality of apertures  88  that are radially aligned with the corresponding plurality of teeth  80 . Each aperture  88  includes a radially extending leading edge  90  and trailing edge  92  with respect to counterclockwise rotation. Accordingly, referring also to FIGS.  17 - 20 , when the primary coupling mechanism is disengaged and sprocket  66  is rotated counterclockwise, the engaging surface  84  of teeth  80  abut leading edges  90  as illustrated in FIGS.  18 - 19 , thereby causing disc  68  to rotate along with sprocket  66  in the counterclockwise direction. However, when sprocket  66  is rotated clockwise, trailing edges  92  of apertures  88  ride over the cam surface  86  of the corresponding teeth  80  as illustrated in FIG. 20. As a result, disc  68  remains stationary.  
         [0053]    A centrally disposed aperture  94  extends axially through disc  68 , and defines a cross-section that conforms to the cross section of operator  22 . Aperture  94  is sized slightly greater than operator  22 , and receives actuator such that rotation of disc  68  causes operator  22  to rotate. It should thus be appreciated that ratchet assembly  64  provides a secondary unidirectional coupling mechanism that, when the primary coupling mechanism is not engaged, permits disc  68  and operator  22  to rotate counterclockwise together with sprocket  66  when the sprocket is rotated counterclockwise. The secondary coupling mechanism also prevents disc  68  and operator  22  from rotating clockwise together when sprocket  66  is rotated clockwise. It should thus be appreciated that the secondary coupling mechanism enables power to be disconnected from fuse block  10  by rotating handle  36  counterclockwise while preventing power from being reconnected by rotating handle  36  clockwise when hub  44  is not depressed (i.e., when door  24  is open).  
         [0054]    It should be further appreciated that the positions of sprocket  66  and plate  68  can be reversed such that plate  68  rests against inner face  58 , and sprocket  66  rests against the outer face of plate  68 . In this orientation, teeth  80  face inwardly to engage apertures  88  in the manner described above.  
         [0055]    Referring once again to FIGS. 5 and 8, a clip  96  is provided that includes a pin  98  and a fastener clamp  100 . Pin  98  is inserted through an aperture  101  extending radially through operator  22 , and is retained by clamp  100  which applies radial pressure against the operator. Pin  98  abuts the inner surface of inner face  58 , and thus sets the position of handle  36  relative to operator  22 . The axial location of aperture  101  on operator  22  further defines the position of pin  34 , and in particular locates the pin  34  in keyway  47  when hub  44  is not depressed.  
         [0056]    Operation of handle  36  will now be described with initial reference to FIGS. 11 and 13. In particular, when door  24  is open, and hub  44  is not manually depressed, spring  39  biases hub  44  outwardly such that hub projections  52  are free from engagement with inner housing ribs  60  and the primary coupling mechanism is disengaged. Hub  44  thus senses that the door is open and disengages the primary coupling mechanism.  
         [0057]    Accordingly, when handle  36  is rotated clockwise in the direction of Arrow A, the secondary coupling mechanism causes housing assembly  41  and sprocket  66  to also rotate clockwise. As described above, housing assembly  41  and sprocket  66  rotate freely relative to operator  22 . Furthermore, because trailing edges  92  of apertures  88  of disc  68  ride over the cam surface  86  of the teeth  80  as also illustrated in FIGS.  15 - 16 , disc  68  and operator  22  remain stationary. Power is thus prevented from being reconnected when the door  24  is open and hub  44  is not depressed.  
         [0058]    However, if handle  36  is rotated counterclockwise, thus causing sprocket  66  to rotate counterclockwise, the engaging surfaces  84  of teeth  80  cause disc  68  to rotate along with sprocket  66  in the counterclockwise direction. Aperture  94  causes operator  22  to rotate counterclockwise along with disc  68 , thereby disconnecting power in fuse block  10 .  
         [0059]    Referring now to FIGS.  21 - 23 , when the door  24  is open, grooves  43  can be manually engaged by, for example, a user&#39;s fingers to pull housing assembly  41  axially outwardly in the direction of Arrow C against the force of spring  39 . The interference between keyway  47  and pin  34  prevents hub  44  from translating outwardly with housing assembly  41 . The relative motion between housing assembly  41  and hub  44  causes protrusions  52  to slide between ribs  60  in the direction of Arrow D and become interlocked with respect to rotational motion. Housing assembly  41  and hub  44  thus provide an override that can be manually actuated to engage the primary coupling mechanism when the door  24  is open. Alternatively, it should be appreciated that hub  44  could be depressed against the spring force to engage protrusions  52  and ribs  60 . Protrusions  52  and ribs  60  have beveled engaging ends to assist with hub insertion into inner housing  38 . Once the protrusions  52  and ribs  60  are interlocked, the primary coupling mechanism is engaged, thereby causing operator  22 , which rotates with hub  44 , to rotate along with housing assembly  41  in both directions. Because aperture  65  of hub  44  engages operator  22 , power can be both connected and disconnected when housing assembly is rotated in the appropriate direction.  
         [0060]    Referring to FIGS. 12 and 14, when door  24  is closed, hub  44  is depressed inwardly with respect to operator  22  in the direction of Arrow B, thereby exposing pin  34  relative to hub  44 . Pin  34  is received by keyway  32  of connector  28 . Door knob  26  can then be rotated clockwise and counterclockwise, which causes keyway  32  to bias pin  34  and operator  22  in the direction of knob rotation. Knob  26  thus directly rotates operator  22  to its “on” and “off” positions to connect and disconnect power through fuse block  10 .  
         [0061]    The present invention thus provides a handle  36  that includes an integral disconnect mechanism that enables power to be connected and disconnected in the fuse block by actuating a traditional doorknob  26  when the door is closed. Handle  36  further enables a user to disconnect, but not reconnect, power when the door is open without first actuating an overriding coupling mechanism. If the overriding coupling mechanism is actuated, a user can disconnect and reconnect power even when door  24  is open. Advantageously, the overriding coupling mechanism is not prone to inadvertent actuation, thereby protecting the user against accidental power connections. Furthermore, because the coupling mechanisms are integral with the handle, modification of existing fuse blocks is not necessary in accordance with the present invention.  
         [0062]    The invention has been described in connection with what are presently considered to be the most practical and preferred embodiments. However, the present invention has been presented by way of illustration and is not intended to be limited to the disclosed embodiments. For example, while the present invention is applicable to fuse blocks of the type described above, it should be appreciated that the present invention is applicable to any handle-operated device that would benefit from the integral primary and secondary coupling mechanisms. Accordingly, those skilled in the art will realize that the invention is intended to encompass all modifications and alternative arrangements included within the spirit and scope of the invention, as set forth by the appended claims.