Abstract:
An electrical cable coupler shell has first and second halves with open end portions configured for telescopic movement along an axis. A first clamp structure is located on the first shell half. A second clamp structure is located on the second shell half. A third clamp structure is receivable in screw threaded engagement with the first clamp structure for movement axially and rotationally relative to the first shell half. The third clamp structure is configured to engage the second clamp structure so as to rotate relative to the second shell half, and simultaneously to impart axial movement to the second shell half, upon moving axially and rotationally in screw threaded engagement with the first clamp structure.

Description:
TECHNICAL FIELD  
       [0001]     This technology relates to couplers for electrical cables.  
       BACKGROUND  
       [0002]     An electrical cable coupler has plug and socket portions on the ends of a pair of electrical cables. Power circuit contacts in the plug are engaged with power circuit contacts in the socket to close a power circuit through the coupler when the plug is inserted in the socket. Safety circuit contacts also are engaged with each other to close a safety circuit through the coupler when the plug is inserted in the socket. In the case of a high voltage mining coupler,.a time delay is required between disengagement of the safety contacts and disengagement of the power circuit contacts when the plug is removed from the socket.  
       SUMMARY  
       [0003]     An electrical cable coupler shell has first and second halves with open end portions configured for telescopic movement along an axis. A first clamp structure is located on the first shell half. A second clamp structure is located on the second shell half. A third clamp structure is receivable in screw threaded engagement with the first clamp structure for movement axially and rotationally relative to the first shell half. The third clamp structure is configured to engage the second clamp structure so as to rotate relative to the second shell half, and simultaneously to impart axial movement to the second shell half, upon moving axially and rotationally in screw threaded engagement with the first clamp structure.  
         [0004]     Preferably, the first clamp structure comprises a screw threaded bolt mounted on the first shell half, and the third clamp structure comprises a nut that is screwed onto the bolt. The nut is movable axially against the second clamp structure upon rotating on the bolt.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  is a view of an electrical cable coupler with a clamp assembly constructed in accordance with the claimed invention.  
         [0006]      FIG. 2  is an enlarged sectional view of parts shown in  FIG. 1 .  
         [0007]      FIG. 3  is a further enlarged view of parts shown in  FIG. 2 .  
         [0008]      FIG. 4  is a view taken on line  4 - 4  of  FIG. 3 .  
         [0009]      FIG. 5  is an exploded view of parts shown in  FIG. 3 .  
         [0010]      FIG. 6  is a view similar to  FIG. 3 , showing parts in different positions.  
         [0011]      FIG. 7  is a view taken on line  7 - 7  of  FIG. 6 .  
         [0012]      FIG. 8  is a view similar to  FIG. 6 , showing parts in different positions.  
         [0013]      FIG. 9  is a view taken on line- 9 - 9  of  FIG. 8 . 
     
    
     DETAILED DESCRIPTION  
       [0014]     The apparatus shown in the drawings has parts that are examples of the elements recited in the claims. The following description thus includes examples of how a person of ordinary skill in the art can make and use the claimed invention. It is presented here to meet the statutory requirements of written description, enablement, and best mode without imposing limitations that are not recited in the claims.  
         [0015]     The apparatus shown in  FIG. 1  is a high voltage mining coupler  10  for a pair of electrical cables  12  and  14 . The coupler  10  includes a shell  20  with first and second halves  22  and  24  that are mounted on the ends of the cables  12  and  14 . The first shell half  22  in this example has an open end portion  26  configured as a socket. The second shell half  24  in this example has an open end portion  28  configured as a plug.  
         [0016]     Each shell half  22  and  24  contains both power circuit contacts and safety circuit contacts. When the plug  28  is being moved into the socket  26 , the power circuit contacts move into engagement before the safety circuit contacts move into engagement. When the plug  28  is being withdrawn from the socket  26 , the power circuit contacts remain in engagement until after the safety circuit contacts are moved out of engagement. The contacts, which are omitted from the drawings for clarity of illustration, may have any suitable configuration known in the art.  
         [0017]     The coupler  10  further includes a clamp assembly  30 . In addition to clamping the two shell halves  22  and  24  together, the clamp assembly  30  is operative to release the plug  28  from the socket  26  in a gradual manner that provides a time delay between disengagement of the safety circuit contacts and disengagement of the power circuit contacts.  
         [0018]     As shown separately in  FIG. 2 , the shell  20  has a longitudinal central axis  39  along which the plug  28  and the socket  26  are movable telescopically. In the illustrated example, the first shell half  22  has a generally conical portion  40  centered on the axis  39 . The socket portion  26  of the first shell half  22  is a generally cylindrical part that also is centered on the axis  39 , and is fixed to the conical portion  40  by machine screws  44 .  
         [0019]     Like the first shell half  22 , the second shell half  24  in this example has a generally conical portion  50  centered on the axis  39 . The plug portion  28  of the second shell half  24  is a generally cylindrical part that is fixed coaxially to the body portion  50  by machine screws  54 . A flange  56  projects radially outward at a location spaced axially from the inner end  58  of the plug  28 . An inner side surface  60  of the flange  56  is perpendicular to the axis  39  and faces toward the inner end  58 . The inner side surface  60  is movable toward and against an opposed end surface  62  on the socket  26  upon movement of the plug  28  into the socket  26 .  
         [0020]     The clamp assembly  30  includes four distinct clamp structures. The first clamp structure is a screw-threaded bolt  70  that is mounted on the first shell half  22 . As shown in  FIGS. 3 and 4 , the bolt  70  has a longitudinal axis  71  and is mounted on a pivot pin  72 . A pair of brackets  74  on the first shell half  22  support the pin  72  for rotation about an axis  75  perpendicular to the central axis  39  ( FIG. 2 ). In this arrangement, the bolt  70  is supported on the first shell half  22  for movement pivotally about that axis  75  between the positions shown in  FIGS. 2 and 3 .  
         [0021]     The second clamp structure is a portion of the flange  56  on the second shell half  24 . As best shown in  FIGS. 3 and 4 , the flange  56  has an outer side surface  78  facing oppositely relative to the inner side surface  60 . An open slot  79  extends radially inward from the peripheral surface  80  of the flange  56  and defines a passage extending axially through the flange  56 .  
         [0022]     The third clamp structure is a nut  90  that is screwed onto the bolt  70 . As shown in  FIG. 5 , the nut  90  has a blind bore  91  with an internal screw thread  92 . A head portion  96  of the nut  90  has flats  98  for gripping by a driving tool, and has a ring-shaped shoulder surface  100  perpendicular to the axis  71 . A narrow intermediate section  102  of the nut  90  extends axially from the head  96  to a wider cylindrical base  104 . The diameter of the intermediate section  102  is just slightly less than the width of the slot  79  in the flange  56  ( FIGS. 3 and 4 ). The length of the intermediate section  102  is just slightly greater than the thickness of the flange  56 . A ring-shaped shoulder surface  106  on the base  104  of the nut  90  also is perpendicular to the axis  71 , and faces axially past the intermediate section  102  toward the opposed shoulder surface  100  on the head  96 .  
         [0023]     The fourth clamp structure is part of a flange  110  on the first shell half  22 . The end surface  62  on the first shell half  22  projects radially outward onto the flange  110 , as shown in  FIGS. 3 and 4 . A passage with a counterbore  111  extends fully through the flange  110  in a direction parallel to the central axis  39 . A slot  113  extends radially outward from the passage  111  to the peripheral surface  114  of the flange  110 . The width of the slot  113  is greater than the diameter of the bolt  70 , but is less than the diameter of the base portion  104  of the nut  90 .  
         [0024]      FIGS. 1 and 8 - 9  show the two shell halves  22  and  24  in their fully engaged positions. In use, the clamp assembly  30  is operative to move the shell halves  22  and  24  axially into and out of these positions. First, the user moves them telescopically into partially engaged positions, such as the positions in which they are shown in  FIGS. 2 and 3 - 4 . Next, with the nut  90  received only a short distance over the bolt  70 , the user swings the bolt  70  pivotally around the axis  75  from the position of  FIGS. 3-4  to the position of  FIGS. 6-7 . This moves the intermediate section  102  of the nut  90  into the slot  79  in the flange  56  on the second shell half  24 . The flange  56  is then captured axially between the opposed shoulder surfaces  100  and  106  on the nut  90 . The bolt  70  pivots through the slot  113  in the other flange  110 . As noted above, the base portion  104  of the nut  90  is wider than the slot  113  and, therefore, can not move into the counterbore  111  through the slot  113 . Instead, the base portion  104  of the nut  90  is moved into the space between the flanges  56  and  110 , and is thus placed in a position from which it can be moved axially into the counterbore  111 .  
         [0025]     Having placed the nut  90  and the bolt  70  in the arrangement shown in  FIGS. 6 and 7 , with the bolt axis  71  parallel to the central axis  39 , the user can screw the nut  90  farther onto the bolt  70  to move the nut  90  axially downward as viewed in the drawings. This causes the first shoulder surface  100  on the nut  90  to move into abutment with the opposed inner side surface  78  on the flange  56 , and to press against that surface  78  so as to push the second shell half  24  axially toward the first shell half  22  as the nut  90  is advanced onto the bolt  70 .  
         [0026]     As the nut  90  moves the shell halves  22  and  24  toward and into the fully engaged positions shown in  FIGS. 8 and 9 , the base  104  of the nut  90  moves into the pocket defined by the counterbore  111 . The base  104  then blocks the bolt  70  from moving pivotally outward through the adjacent slot  113  until the user later retracts the nut  90  along the bolt  70 . Unscrewing the nut  90  causes the second shoulder surface  106  on the nut  90  to move into abutment with the opposed outer side surface  60  on the flange  56 , and thereby to draw the second shell half  24  axially away from the first shell half  22 . Importantly, unscrewing the nut  90  moves the shell halves  22  and  24  apart in a gradual manner that can provide a specified time delay, such as a delay of at least one second, between disengagement of the safety circuit contacts and subsequent disengagement of the power circuit contacts inside the shell halves  22  and  24 . The depth of the counterbore  111  causes the nut  90  to block the bolt  70  from pivoting outward through the slot  113  until the safety circuit contacts have been disengaged. At that time, by swinging the nut  90  and bolt  70  pivotally back from the positions of  FIGS. 6-7  toward the positions of  FIGS. 3-4 , the user can remove the plug  28  fully from the socket  26 , and can separate the two shell halves  22  and  24  fully from each other, without removing the nut  90  from the bolt  70 .  
         [0027]     The patentable scope of the invention is defined by the claims, and may include other examples of how the invention can be made and used. In this regard the plug. 28  and the socket  26  could be reversed relative to the clamp assembly  30 . Such other examples, which may be available either before or after the application filing date, are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they have equivalent structural elements with insubstantial differences from the literal language of the claims.