Abstract:
A method of manufacturing a split nut comprising the steps of fabricating a first semi-arc shaped member ( 1 ) having thin-walled hinge parts ( 2, 12 ) and thick-walled center parts ( 5, 15 ) at one end and thin-walled engagement parts ( 3, 13 ) at the other end and a second semi-arc shaped member ( 11 ) of the same shape and size as those of the first semi-arc shaped member ( 1 ) and assembling said first and second semi-arcshaped members together enabling the first and second semi-arc shaped members ( 1, 11 ) to be provided by a single metal mold.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention provides a method for manufacturing a split nut.  
         [0003]     2. Description of the Prior Art  
         [0004]     Traditionally, the split nut is a turning nut consisting of two semi-arc-shaped parts that can be opened and separated by turning. These two pieces, being semi-arc-shaped parts, are hinged together at one end and caught at the other end by a grasping mechanism. The aforementioned grasping mechanism is configured with the protrusion at one end of one semi-arc-shaped piece and the depression at one end of the other semi-arc-shaped piece. The two semi-arc-shaped pieces can be released and separated by releasing the grasping mechanism. Additionally, the inner circular surface of each of the aforementioned semi-arc-shaped pieces is tapped and threaded.  
         [0005]     It is necessary to prepare two typed of metal molds when manufacturing the aforementioned turning nut. There is one type for each semi-arc-shaped piece, since the two semi-arc-shaped pieces are different in shape. This means that two metal molds of different shapes have to be prepared thus increasing the cost of manufacturing the aforementioned turning nut because the number of types of metal molds is increased to two.  
         [0006]     The aforementioned turning nut presents one other problem: The grasping mechanism between the protruding section and the depressed section is caught in the circumferential direction and is therefore apt to release due to vibration and other factors.  
         [0007]     What is desired is to provide a method of manufacturing the split nut that will reduce the manufacturing cost and provide a grasping configuration that ensures easy catch of the catching section while minimizing unintended release.  
       SUMMARY OF INVENTION  
       [0008]     The present invention provides a method for manufacturing a split nut which is less expensive than conventional techniques and wherein the grasping portion of the split nut is improved thus minimizing the possibility of unintended release.  
         [0009]     The manufacturing method comprises preparing first semi-arc-shaped part and second semi-arc shaped parts each having a thin-walled hinge section, a thick-walled center section and a thin-walled catching section. The manufacturing method of the present invention further couples the aforementioned first and second semi-arc-shaped parts together in such a way that the catching sections of both parts face each other and overlap such that the hinge sections of both parts face each other and overlap. The manufacturing method has an additional work process that configures and taps the threads on the inner circular surface of the aforementioned combined assembly of the first and second semi-arc-shaped parts.  
         [0010]     Another feature of this invention is that the catching sections of the first and second semi-arc shaped parts have identical main subsections that extend out horizontally and have identical engaging teeth connected to the main subsection and protruding step-wise with respect to the main subsection. Additionally, the main subsections and the engaging tooth subsections are slanted in the same direction at the edge surface, where they mate with corresponding catching sections.  
         [0011]     First and second semi-arc-shaped parts, which are identical in shape and size and have a thin walled hinge section at one end, a thick-walled center section and a thin-walled catching section at the other end are utilized in the manufacturing method. Because the parts are identical, only one type of metal mold is necessary for both the first and second semi-arc-shaped parts. This cuts the number of the types of the required metal molds to one, thereby reducing the cost of manufacturing:  
         [0012]     Additionally, the tapping operation for the inner circular surfaces of the semi-arc-shaped parts is performed after the first and second semi-arc-shaped parts are mated at the respective hinge and catching sections. This allows the opposing inner circular surfaces of the first and second semi-arc-shaped parts to be threaded together, particularly with respect to the thick-walled center sections.  
         [0013]     The split nut, manufactured utilizing the method of the present invention, has one thin-walled hinge section overlapping atop the other thin-walled hinge section. Additionally, one thin-walled catching section overlaps the other thin-walled catching section making it possible to make the total thickness of the combined hinge sections or the total thickness of the combined catching sections identical in thickness to the thick-walled center section.  
         [0014]     Furthermore, the main subsection of the catching section and the tooth subsection are slanted in the same direction with respect to the opposing mating edge surfaces. The benefits of this arrangement are that it is easy to catch along the slanted surface, and that once caught it is resistant to unintended release.  
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0015]     For a better understanding of the present invention as well as other objects and further features thereof, reference is made to the following description which is to be read in conjunction with the accompanying drawing wherein:  
         [0016]      FIG. 1  ( a ) is a top view of the first and second semi-arc-shaped parts used in the split nut manufacturing method of the present invention, such parts being arranged so that they face each other;  
         [0017]      FIG. 1  ( b ) is a frontal view of the first and second semi-arc-shaped parts;  
         [0018]      FIG. 2  is a top view of the first and second semi-arc-shaped parts after going through the assembly process of the aforementioned manufacturing method;  
         [0019]     FIGS.  3 ( a ) and ( b ) are cut views along the III-III line in  FIG. 2  during the process of setting the rivet in the aforementioned manufacturing method;  
         [0020]      FIG. 4  is a cut view along the IV-IV line in  FIG. 2  during the tapping process of the aforementioned manufacturing method;  
         [0021]      FIG. 5  is an oblique view of the split nut obtained through the aforementioned manufacturing method;  
         [0022]      FIG. 6  shows the state in which the splitting pieces of the first and second semi-arc-shaped parts are released and opened; and  
         [0023]     FIGS.  7  ( a ) and ( b ) provide diagrams that explain the usage conditions of the aforementioned split nut.  
     
    
     DESCRIPTION OF THE INVENTION  
       [0024]     Referring to  FIGS. 1-4 , the split nut manufacturing method of the present invention is explained below.  
         [0025]      FIG. 1  ( a ) is a top view of the first semi-arc-shaped part  1  and the second semi-arc-shaped part  11 , which are used in the aforementioned manufacturing method, being arranged to face each other.  FIG. 1  ( b ) is a frontal view of the first and second semi-arc-shaped parts  1  and  11 , respectively.  
         [0026]     As shown in FIGS.  1  ( a ) and ( b ), the first and second semi-arc-shaped parts, being  1  and  11  respectively, which are identical in shape and size, are prepared. At this time the first semi-arc-shaped part  1  is positioned so that its base surface faces the opposite direction with respect to the base surface of the second semi-arc-shaped part  11 . The first semi-arc-shaped part  1  and the second semi-arc-shaped part  11  are placed in radial orientation so that they face each other.  
         [0027]     The aforementioned first and second semi-arc-shaped parts  1  and  11  contain the thin walled hinge sections  2  and  12  at one end, the thick-walled center sections  5  and  15 , and the thin-walled catching sections  3  and  13  at the other end.  
         [0028]     Additionally, the inner circular surfaces  7  and  17  of the first and second semi-arc-shaped parts  1  and  11  are flat and smooth. In other words, the inner circular surfaces  7  and  17  of the first and second semi-arc-shaped parts  1  and  11  are not yet threaded.  
         [0029]     The hinge sections  2  and  12  have the through-holes  4  and  14  going from one end surface to the other end surface. The through-holes  4  and  14  have tapered sections at the other end surface. (See  FIG. 3 ( a )).  
         [0030]     The aforementioned catching sections  3  and  13  have the main subsections  3 ( a ) and  13 ( a ) extending horizontally, as well as the tooth subsections  3 ( a ) and  13 ( a ), which are connected to the main subsection and protrude step-wise with respect to the main subsection. The thickness of the aforementioned main subsections  3 ( a ) and  13 ( a ) gets progressively thinner moving away from the center sections  5  and  15  toward the teeth subsections  3 ( b ) and  13 ( b ). Moreover, the mating surfaces of the aforementioned main subsections  3 ( a ) and  13 ( b ), where the opposing pieces overlap each other, and the tooth subsections  3 ( b ) and  13 ( b ) are slanted in the same direction with respect to the other horizontal plane. However, the non-mating surfaces, where the opposing pieces do not overlap each other, of the aforementioned main subsections  3 ( a ) and  13 ( a ) and the teeth subsections  3 ( b ) and  13 ( b ) are not slanted with respect to the horizontal plane.  
         [0031]     The assembly step is performed next. As shown in  FIG. 2 , hinge sections  2  and  12  of the first and second semi-arc-shaped parts  1  and  11  are arranged to overlap, and the catching sections  3  and  13  of the first and second semi-arc-shaped parts  1  and  11  are also arranged to overlap. This configuration lines up the center axes of the through-holes of the hinge sections  2  and  12 . Additionally, the catching sections  3  and  13  will couple with each other. At this time, with respect to the catching sections  3  and  13 , the slanted surface of the main subsection  3 ( a ) will overlap and slanted surface of the tooth section  13 ( b ). At the same time the slanted surface of the main subsection  13 ( a ) will overlap the slanted surface of the tooth subsection  3 ( b ) (See  FIG. 1 ( b )).  
         [0032]     The rivet-set step is performed next. As shown in FIGS.  3 ( a ) and ( b ), the rivet  21  is placed in the through-holes  4  and  14  of the hinge sections  2  and  12 . Since the tapered shape of the aforementioned through-hole  14  is the same as the shape of the head of the rivet  21 , the top surface of the rivet  21  will be even with the top surface of the remaining hinge section  12 . Then, the tip of the rivet  21  is spread by the rivet heading tool  200  and is fastened to the hinge section  2 . As far as riveting is concerned, it is easy to perform the heading of the rivet  21  because the hole is tapered from the top surface along the axis and the thickness is reduced at the top surface near the hole.  
         [0033]     As shown in  FIG. 4 , the last step is to tap the thread on the inner circular surfaces  7  and  17  of the semi-arc-shaped parts  1  and  11  using the screw tapping tool  201 .  
         [0034]     The aforementioned manufacturing method of the split nut uses parts that are identical in shape and size for the first and second semi-arc-shaped parts  1  and  11 , which consist of the thin-walled hinge sections  2  and  12  at one end, the thick-walled center sections  5  and  15 , and the thin-walled catching sections  3  and  13  at the other end. Therefore, both the first and second semi-art-shaped parts  1  and  11  can be obtained from the same mold, the number of types of metal molds needed to obtain the first and second semi-arc-shaped parts  1  and  11  thus being reduced to one, making it possible to lower the cost of manufacturing.  
         [0035]     Additionally, the tapping operation of the inner circular surface of the semi-arc-shaped parts  1  and  11  is performed after the first and second semi-arc-shaped parts  1  and  11  are mated at their respective hinge sections  2  and  12  and the catching sections  3  and  13 . This allows the opposing inner circular surfaces of the first and second semi-arc-shaped parts  1  and  11  to be threaded together, particularly with respect to the thick-walled center sections  5  and  15 .  
         [0036]     The split nut, being manufactured through the subject manufacturing method, overlaps one thin-walled hinge section  2  atop the other thin-walled hinge section  12 . Moreover, the split nut overlaps one thin-walled catching section  3  atop the other thin-walled catching section  13 . Therefore, the total thickness of the combined hinge sections  2  and  12  and the total thickness of the combined catching sections  3  and  13  are identical to that of the thick-walled center section  5  or  15 .  
         [0037]      FIG. 5  shows an oblique, or perspective, view of the split nut  100 , which is manufactured through the subject method.  
         [0038]     The aforementioned split nut  100  contains the first semi-arc-shaped split piece  31 , which is obtained form the first semi-arc-shaped part  11 . The first and second semi-arc-shaped split pieces  31  and  41  are linked to each other by the hinge sections  32  and  42 , which are located at one end. Additionally, the aforementioned semi-arc-shaped split pieces  31  and  41  have the catching sections  33  and  43  at the other end. If these catching sections  33  and  43  are released from each other, the first and second semi-arc-shaped split pieces  31  and  41  can be opened up as shown in  FIG. 6 .  
         [0039]     If the first and second semi-arc-shaped split pieces  31  and  41  are gradually closed, the tooth subsection  43 ( b ) of the catching section  43  will climb up along the slope of the tooth subsection  33   b  of the catching section  33 , whereupon the catching section  33  will catch the catching section  43 . At the catching sections  33  and  43 , the slope of the main subsection  33   a  will overlap the slanted slope of the tooth subsection  43   b . Similarly, the slope of the main subsection  43 ( a ) will overlap the slope of the tooth subsection  33   b.    
         [0040]     Attaching the aforementioned split nut  100  is a long hanging bolt is described below.  
         [0041]     As shown in  FIG. 7  ( a ), the hanging bolt  300  is inserted through the through-hole (not shown in the figure) of the hanger  302 . The nut  301  is then attached to the bottom of the hanging bolt  300 . The nut  301  is rotated to move up along the bolt  300  to the designated point where the hanger  302  is supported by the nut  301 .  
         [0042]     Next, the catching sections  33  and  34  of the aforementioned first and second semi-arc-shaped split pieces  31  and  41  are released from each other, and the first and second semi-arc-shaped split pieces  31  and  41  are opened up. The first and second arc-shaped-pieces  31  and  41  are used to clamp the hanging bolt  300  in radial orientation at the desired position.  
         [0043]     The aforementioned first and second semi-arc-shaped split pieces  31  and  41  are closed, and the catching sections  33  and  43  of the first and second semi-arc-shaped split pieces  31  and  41  catch each other. Thus the split nut  100  is attached to the hanging bolt  300 , as shown in  FIG. 7 ( b ).  
         [0044]     Lastly, the aforementioned split nut  100  is tightened to secure the hanger  302  at the designated position on the hanging bolt  300 .  
         [0045]     As described above, the split nut  100  can be attached to any desired position on the hanging bolt  300  without being attached from the tip of the hanging bolt  300  and moving up. This is possible only because the first and second semi-arc-shaped split pieces  31  and  41  can be opened or closed.  
         [0046]     Additionally, the aforementioned first and second semi-arc-shaped split pieces  31  and  41  will not be separated because they are linked at the other end by the hinge sections  32  and  42 . Therefore, the aforementioned split nut  100  provides good operability for the attachment step.  
         [0047]     The split nut  100  is described in the above embodiment, is a hexagonal nut. However, the shape of the split nut obtained by the subject invention can have any shape besides a hexagonal one. For example, rectangular or round split nuts can be obtained using the subject invention.  
         [0048]     The shape of the first and second semi-arc-shaped parts used in the subject invention is not limited to the shape described in the above embodiment. Actually, it can be of any shape as along as the first and second semi-arc-shaped parts are identical to each other and have a thin-walled hinge section at one end, a thick-walled center section and a thin-walled catching section at the other end.  
         [0049]     For example, in the aforementioned embodiment the one surface of the surface of the first and second semi-arc-shaped parts  1  and  11  is flat all the way across the hinge sections  2  and  12 , the center sections  5  and  15  and the catching sections  3  and  13 . However, this configuration can be changed so that the center section and the hinge section are flat on one surface at one end and the center section while the catching section are flat on the other surface at the other end. In other words, the configuration can be such that the hinge section can be on the upper side and the catching section can be at the bottom side, or vice versa, for each of the first and second semi-arc-shaped parts.  
         [0050]     In the method described hereinabove, the step of setting the rivet is performed prior to the tapping step. This allows the first and second semi-arc-shaped parts (already linked) to be tapped together, eliminating the need for a test jig to hold those parts together securely. In other words, if the step of setting the rivet is not performed prior to the tapping operation, the first and second semi-arc-shaped parts will easily come apart during the tapping operation, which is not desirable.  
         [0051]     As stated above, according to the manufacturing method of the present invention the aforementioned first semi-arc-shaped part and the second semi-arc-shaped part are identical in shape and size, so that each has a thin-walled hinge section, a thick-walled center section and a thin-walled catching section. Both the first and second semi-arc-shaped parts can be obtained form one type of metal mold, thus reducing the cost of manufacturing.  
         [0052]     Moreover, the tapping operation of the inner circular surfaces of the semi-arc-shaped parts is performed after the first and second semi-arc-shaped parts are mated at the respective hinge and catching sections. This allows the opposing inner circular surfaces of the first and second semi-arc-shaped parts to be threaded together.  
         [0053]     The split nut, being manufactured through the subject method, overlaps one thin-walled hinge section atop the other thin-walled hinge section. Additionally, it overlaps one thin-walled catching section atop the other thin-walled catching section. Therefore, it is possible to make the total thickness of the combined hinge sections or the total thickness of the combined catching sections identical to that of the thick-walled center section. Additionally, the main subsection of the catching section and the tooth subsection are slanted in the same direction with respect to their opposing mating edge surfaces. The benefits of this configuration are that it is easy to catch along the slanted surface, and that once caught there is a reduced possibility of unintended release.  
         [0054]     While the invention has been described with reference to its preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its essential teachings.