Patent Abstract:
A connector block having an elongated body with an end wall at one end. A resilient, cantilever arm extends from one side of the end wall over the wall to the other side of the wall and terminates in a free end at the other side of the end wall. The arm is spaced from the outer face of the end wall to define, with the outer face, a slot that snugly receives signal lines. The cantilevered arm is tapered in thickness toward its free end in a manner to have the end wall curl back over itself when the block is used by exploding a detonator carried by the block.

Full Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention is connected toward an improved connector block.  
           [0003]    2. Description of the Related Art including Information Disclosed under CFR §§1.97-1.99  
           [0004]    A connector block is used in blasting operations to connect a detonator to at least one signal transmission line. An example of such a block is shown in U.S. Pat. No. 5,703,319.  
           [0005]    A connector block has an elongated body member for holding a detonator therein with the explosive end of the detonator at one end of the block. Means are provided at this one end of the block for holding signal transmission lines adjacent the explosive end of the detonator. Several of the new connector blocks use a cantilevered arm on the end wall of the block at the one end to hold the signal lines adjacent to the explosive end of the detonator at the one end wall of the block. The signal lines are located in a narrow space or slot formed between the arm and the one end wall of the block and are inserted into that space through an entrance between the free end of the arm and the end wall. The slot is shaped and sized to hold the lines quite firmly, closely adjacent to the end of the detonator.  
           [0006]    These known connector blocks can be dangerous however when detonated. Often the cantilevered arm will blow off the block when the detonator is detonated and the arm, as a small missile, could injure someone.  
         SUMMARY OF THE INVENTION  
         [0007]    It is the purpose of the present invention to provide connector blocks of the type employing a cantilevered arm to hold the signal lines that are safer in operation than the known blocks. More particularly, it is the purpose of the present invention to provide connector blocks in which the cantilevered arm remains attached to the block when detonated.  
           [0008]    In accordance with the present invention there is provided a connector block having a cantilevered arm at least the front portion of which is tapered from a thin front end to a thicker middle section. As a result of this construction, the cantilevered arm peels or rolls back from its free front end toward its supported rear end, away from the end wall of the block, instead of being blown off the connector block when the detonator is detonated. With the arm remaining attached to the block during detonation, the block is much safer in use.  
           [0009]    The invention is particularly directed toward a connector block having an elongated body, the body having an end wall at one end, the end wall having an outer face. An opening in the end wall extends through the end wall to the outer face. The body supports a detonator with a leading explosive end of the detonator extending into the opening in the end wall and at least close to the outer face of the end wall. A resilient, cantilever arm extends from one side of the end wall over the outer face of the end wall to the other side of the end wall and terminates in a free end at the other side of the end wall. The arm is spaced from the outer face to define, with the outer face, a slot that snugly receives signal lines so as to locate the signal lines adjacent the opening. The free end of the arm and the end wall form an entrance to the slot that is narrower than the slot. The cantilevered arm is tapered in thickness, from a point spaced along its length from its connection to the end wall determined by where the arm will curl rearwardly over itself, instead of separating from the end wall, when the detonator is exploded, to adjacent its free end where it is thinnest. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is perspective view of a known connector block;  
         [0011]    [0011]FIG. 2 is a cross-section view of the known block taken along line  2 - 2  in FIG. 1;  
         [0012]    [0012]FIG. 3 is a detail view of the entrance to the slot in the known block;  
         [0013]    [0013]FIG. 4 is a perspective view of a known detonator;  
         [0014]    [0014]FIG. 5 is a view similar to FIG. 2 but with the known detonator and signal lines mounted on the known block;  
         [0015]    [0015]FIG. 6 is a view similar to FIG. 2 showing the improved connector block; and  
         [0016]    [0016]FIG. 7 is a view similar to FIG. 6 but showing the block after the detonator has exploded. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    A prior art connector block  1 , as shown in FIGS. 1 and 2, has an elongated body  3  with side walls  5  joined by a bottom wall  7  defining an open, elongated channel  9 . One end of the body  3  is closed by an end wall  11 . The other end of the body  3  could also be partly closed by a second end wall  13  if desired. The channel  9  holds a detonator DE as will be described. The detonator DE can rest on the bottom wall  7  of the body  3 . Preferably, a detonator support  15  is provided on the bottom wall  7  and supports the detonator DE in the channel  9 . A cover  17  can be provided to close the body  3 . The cover  17  can be attached to the body  3  to be on one side of the body when not in use. The cover  17 , in use, rests on the top free edges  19  of the side walls  5 . Cooperating locking means (not shown) are provided on the cover  17  and the side walls  5  of the body  3  for locking the cover  17  to the body  3  when in use. The cover  17  can also have retaining means  20  on its bottom surface  21  for cooperating with the detonator DE to retain the detonator in place within the body  3  as will be described. The end wall  11  has a cylindrical opening  23  there through which opening is aligned with the detonator support  15 .  
         [0018]    The outer surface  31  of the end wall  11  has a semicylindrical surface portion  33 , generally overlying the opening  23  and extending across the height of the end wall  11 . This curved surface portion  33  is transverse to the longitudinal axis  35  of the opening  23 . A pair of stop members  37  within the opening  23  partially close the opening adjacent the surface portion  33 , the stop members  37  integral with the end wall  11 .  
         [0019]    The known connector block  1  includes a resilient, cantilevered arm  41  extending from one side  43  of the end wall  11  over and across its outer surface  31 , substantially covering the outer surface  31 . The arm  41  has a main body portion  45 , the length of which constitutes a substantial portion of the length of the arm, and which extends from the one side  43  of the end wall  11 . The main body portion  45  is of the same thickness over its length and is spaced from the outer surface  31  of the end wall  11  and curved over the semicylindrical surface portion  33  in a manner to form a narrow slot  47  which slot is of uniform width over at least a major portion of its length. The arm  41  has a free end portion  49  extending from the main body portion  45  of the arm  41 , which tapers to a point.  
         [0020]    The free end portion  49  of the arm  41  forms a v-shaped entrance  51  with an entrance portion  53  of the outer surface  31  of the end wall  11  adjacent the other side  55  of the end wall  11  as shown in detail in FIG. 3. The entrance  51  provides access into the slot  47 . Preferably, the free end portion  49  of the arm  41  has its inner surface  57  angled outwardly forming one slanted side of the entrance  51 . The entrance portion  53  on the end wall  11  has an inwardly angled surface  59  forming the other slanted side of the entrance  51 . The end of the slot  47  near the other side  55  of the end wall  11  undercuts the entrance portion  53  forming a resilient finger  61  that, with the free end portion  49  of the resilient arm  41 , substantially closes the entrance  51 . This type of connector block is known.  
         [0021]    The known block  1  is used with a detonator DE. The detonator DE, as shown in FIG. 4, has a casing C with a leading explosive end LE and an open trailing end TE. The casing C is preferably cylindrical in shape although it could have other shapes. The open trailing end TE is closed by a resilient bushing B through which a detonator signal line DSL is passed into the casing C. The casing C is crimped about the bushing B as shown at CR. At least one crimp and preferably two are employed. Detonators of this type are well known.  
         [0022]    To use the block  1 , the detonator DE in placed in the channel  9  of the block  1  with its leading end LE inserted into the opening  23  in the end wall  11  and tight against the stops  37  as shown in FIG. 5. The stops  37  serve to locate the explosive end LE of the detonator DE relative to the semi-cylindrical surface  33  of the end wall  11 . The casing C rests on the support  15  in the channel  9  and the detonator signal line DSL extends rearwardly out of the body  3  through a slot  61  in the other end wall  13 . The cover  17  is used to close the body  3  and retain the detonator DE tight against the stops  37  and the support  15  with the retaining means  19  on the bottom of the cover  17 . The retaining means  19  partly encircle one of the crimps CR on the detonator casing C preventing both lateral and longitudinal movement of the detonator.  
         [0023]    The signal lines SL are passed through the entrance  51  into the slot  47  between the resilient finger  61  and the free end portion  49  of the resilient arm  41 . The slot  47  is just wide enough to snugly receive the signal lines SL which lines, when in the slot  47 , extend transverse to the longitudinal axis  35  of the opening  23 . The signal lines SL are placed in the slot  47  through the entrance  51  one at a time. The resilient arm  41  helps hold the signal lines SL in place within the slot. The signal lines SL lie closely adjacent to the leading explosive end LE of the detonator DE, all about the same distance therefrom. Detonation of the detonator DE sends a signal through each signal line SL.  
         [0024]    In accordance with the present invention, the cantilevered arm  41 ′ of the connector block  1 ′, as shown in FIG. 6, is modified to ensure that it remains with the body  3 ′ of the block when the detonator DE is detonated. To this end, the main body portion  45 ′ of the arm  41 ′ is modified to taper in thickness, from a point spaced from its connection to the end wall determined by where the free end of the arm will curl back on itself when the detonator is exploded, to the free end portion  49 ′. Preferably, the main body portion  45 ′ of the arm  41 ′ is modified to taper in thickness at least from about its mid-point  71 , at about the longitudinal axis  35 ′ of the opening  23 ′ in the end wall  11 ′, to the free end portion  49 ′, tapering from a thick cross-section at the mid-point  71  to a thin cross-section adjacent the free end portion  49 ′. The free end portion  49 ′ is also modified to have a thickness at its thick end equal to the thickness at the thin end  73  of the body portion. The tapered, forward portion  75  of the main body  45 ′ of the arm  41 ′ allows the arm to curl backward, as shown in FIG. 7, when the detonator DE is exploded, starting from its free end portion  49 ′, instead of being blown off. Thus the arm  41 ′ stays connected to the block during detonation making the block much safer in use. The tapering of the arm  41 ′ is done in a manner to leave the thickness of the slot  47 ′ unchanged.  
         [0025]    If desired, the main body  45 ′ of the arm can be tapered back from its free end portion  49 ′ to a point close to the location where the arm is connected to the end wall. The arm would be tapered for about three quarters of its length in this case provided a longer tapered forward portion  75  of the arm  41 ′ making it still easier to curl the arm backward on itself during detonation.  
         [0026]    The cantilevered arm  41  has been described as being resilient. The arm  41  could, in some cases, be rigid rather than springy with the arm slightly squeezing the signal lines SL to securely hold them in the slot  47  and with the resilient finger  61  in the entrance  51  designed to allow passage of the signal lines SL into the slot without movement of the arm  41 .  
         [0027]    While one form of known connecting block has been described, other similar types of known blocks, using a cantilevered arm to hold the signal lines, can be employed, but with the arm modified according to this invention. The cantilevered arm and entrance is designed according to the present invention to securely retain all the signal lines in position within the slot adjacent the detonator, while still allowing entrance of the lines into the slot and also ensuring that the arm is tapered in a manner allowing it to curl starting from its front end when the detonator is exploded.

Technology Classification (CPC): 5