Patent Publication Number: US-2006008338-A1

Title: Plate nut connector system without nut holder for inserting the nut into the struts from the front surface direction of the strut

Description:
RELATED APPLICATION  
      This application is a continuation-in-part application of U.S. patent application Ser. No. 10/884,567, filed on Jul. 6, 2004, the disclosure of which is incorporated by reference as if fully set forth herein. 
    
    
     BACKGROUND OF THE INVENTION  
      The present invention relates to a plate nut connector system without nut holder for inserting the nut into the struts from the front surface direction of the strut.  
      More particularly, this invention relates to a plate nut connector system without nut holder, which enables for the struts to hold wires and ducts in a groove formed in the struts.  
      In order to connect the struts, the workers on electric construction sites should perform time consuming and complicated jobs. The procedure for the job includes the steps of 1) positioning the strut support plate having two bolt holes on the rear face of a connecting point of the two struts, 2) inserting the bolts to the strut support through the washers, 3) mounting the washers on the bolts from the insides of the struts, and 4) engaging the nuts to the bolts and fasten the nuts. Due to the limited space on the inside of the structure of the struts, however, it is not easy to hold the nuts, normally half an inch in size, to fasten them from the inside of the strut. Additionally, the total thickness of the accessories (thickness of the bolt head, plus the thickness of a washer, plus the thickness of a support plate) easily reach over the gap between the strut&#39;s rear surface and the bottom of the metal tubing, which contains electric wires that come out from a four switch junction box and are sustained by tube hangers. Workers should bend the metal tubing to make it turn around the connection points. It costs additional time and effort. Not only time, but the number of parts in the prior method is nine and fifteen for the two holes and four connections respectively. However, the number of parts has decreased to five and nine according to the present invention.  
      Accordingly, a need for a plate nut connector system has been present for a long time considering the wide range of the application. This invention is directed to solve these problems and satisfy the long-felt need.  
     SUMMARY OF THE INVENTION  
      The present invention contrives to solve the disadvantages of the prior art.  
      An objective of the invention is to provide a plate nut connector system, which connects two strut-like members conveniently.  
      Another objective of the invention is to provide a plate nut connector system, which enables the plate nut can be inserted from the front.  
      Still another objective of the invention is to provide a plate nut connector system, which enables to choose proper nut holes from many holes of different sizes.  
      A plate nut connector system includes a first strut, a second strut, a plate nut, two or more nut holes of different sizes through the hole-bearing surfaces of the plate nut, and two or more bolts corresponding to the nut holes.  
      The plate nut includes hole-bearing surfaces and plank surfaces connecting the hole-bearing surfaces.  
      Each of the first and second struts includes two side walls, a bottom wall, and one or more oval shaped holes on the bottom wall. Each of the side walls includes an inner surface and an outer surface. The bottom wall connects the two side walls to form a groove, and the bottom wall includes an inner surface and an outer surface.  
      The plate nut connector connects the first and second struts by screwing the bolts from the outer surface of the bottom wall of the struts, through the bottom wall of the struts, into the nut holes on the plate nut, and the plate nut is adapted to be inserted into the groove perpendicularly to the longitudinal direction of the struts from the front side. The nut holes of the same size are used selectively. The groove formed by the two side walls and the bottom wall is adapted to contain wires or pipes.  
      The plate nut is fitted inside the groove with a predetermined margin.  
      The cross-section of the plate nut is adapted for inserting the plate nut into the longitudinal groove of the struts from the front. The cross-section of the plate nut includes a trapezoid and rectangle.  
      The length of the plate nut depends on the number of the nut holes on the plate nut. The plate nut is preferably flat. The plate nut is ten (10) millimeters thick, and the plate nut is seven (7) to fifteen (15) centimeters long. The width of the plate nut is narrower than the gap between the inner surfaces of the side walls by a predetermined value. The predetermined value is from about zero point one (0.1) millimeters to about zero point three (0.3) millimeters. The nut hole has a diameter from about one point five (1.5) to about one point nine (1.9) centimeters.  
      The plate nut includes four (4) nut holes.  
      The plate nut connector system further includes two or more washer for tightening the bolts.  
      The plate nut is adapted to the groove formed by the bottom wall and the side walls. The side wall of the strut includes a flange along the brim the groove, and the flanges on both sides face inwardly.  
      The plate nut is bent along the mid-line between the nut holes on the hole-bearing surface of the plate nut by a predetermined angle. The predetermined angle is from about twenty five (25) to about one hundred fifty five (155) degrees.  
      The plate nut is bent along the mid-line on the plank surfaces of the plate nut by a predetermined angle. The predetermined angle is from about twenty five (25) to about one hundred fifty five (155) degrees. The plate nut is from about eight (8) to about twelve (12) millimeters thick, the length of each bent wing from about eight (8) to about twelve (12) centimeters, and the width of each bend wing approximately two (2) millimeters shorter than the gap between the two side walls of the struts. The nut hole has a diameter from about one point five (1.5) to about one point nine (1.9) centimeters.  
      The advantages of the present invention are: (1) the plate nut connector system is convenient to use in a cramped space; (2) the plate nut connector system enables to connect the struts suitable to accept wires and ducts; (3) the plate nut connector system is convenient to use appropriate nut holes selectively from nut holes of different sizes.  
      Although the present invention is briefly summarized, the fuller understanding of the invention can be obtained by the following drawings, detailed description and appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and other features, aspects and advantages of the present invention will become better understood with reference to the accompanying drawings, wherein:  
       FIG. 1  is an expanded perspective view showing the connection method of the two struts with a plate metal nut according to the present invention;  
       FIG. 2  is a front view of the assembled struts and metal plate nut according to the present invention;  
       FIG. 3  is a rear view of the assembled struts and metal plate nut;  
       FIG. 4  is a cross-sectional view of the assembled struts and metal plate nut along the line IV-IV in  FIG. 2 ;  
       FIG. 5  is a schematic cross-sectional drawing along IV-IV showing engaging a plate nut to a strut from the front side of the strut;  
       FIG. 6  is a cross-sectional view of the assembled struts and metal plate nut along the line VI-VI in  FIG. 2 ;  
       FIG. 7  is an expanded perspective view showing the connection method of two struts with another embodiment of a plate metal nut according to the present invention;  
       FIG. 8  is a plane view of the third embodiment of the plate nut according to the present invention; and  
       FIG. 9  is a plan view of a plate nut with nut holes of different sizes. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      The U.S. patent application Ser. No. 10/884,567 is incorporated by reference into this disclosure as if fully set forth herein.  
       FIG. 1  shows an expanded perspective view showing the plate nut connector system  100  connecting the two struts  10 ,  20  with a plate metal nut  30  according to the present invention as shown in  FIG. 2 ,  FIG. 3 , and  FIG. 4 .  
      A plate nut connector system  100  includes a first strut  10 , a second strut  20 , a plate nut  30 , two or more nut holes  40  of different sizes (refer to  FIG. 9 ) through hole-bearing surfaces  31  of the plate nut  30 , and two or more bolts  50  corresponding to the nut holes  40 .  
      The plate nut  30  includes hole-bearing surfaces  31  and plank surfaces  32  connecting the hole-bearing surfaces  31 .  
      Each of the first and second struts  10 ,  20  includes two side walls  12 , a bottom wall  14 , and one or more oval shaped holes  16  on the bottom wall  14 . Each of the side walls  12  includes an inner surface  11  and an outer surface  13 . The bottom wall  14  connects the two side walls  12  to form a groove  18 , and the bottom wall  14  includes an inner surface  15  and an outer surface  17 .  
      The plate nut connector system  100  connects the first and second struts  10 ,  20  by screwing the bolts  50  from the outer surface  17  of the bottom wall  14  of the struts  10 ,  20 , through the bottom wall  14  of the struts  10 ,  20 , into the nut holes  40  on the plate nut  30 , and the plate nut  30  is adapted to be inserted into the groove  18  perpendicularly to the longitudinal direction of the struts  10 ,  20  from the front side  19  as shown in  FIG. 5 . The nut holes  40  ( 42  or  44  in  FIG. 9 ) of the same size are used selectively. The groove  18  formed by the two side walls  12  and the bottom wall  14  is adapted to contain wires or pipes.  
      The plate nut  30  is fitted inside the groove  18  with a predetermined margin.  
      The cross-section  34  of the plate nut  30  is adapted for inserting the plate nut  30  into the longitudinal groove  18  of the struts  10 ,  20  from the front  19 . The cross-section  34  of the plate nut  30  includes a trapezoid and rectangle.  
      The length of the plate nut  30  depends on the number of the nut holes  40  on the plate nut  30 . The plate nut  30  is preferably flat. The plate nut  30  is ten (10) millimeters thick, and the plate nut  30  is seven ( 7 ) to fifteen (15) centimeters long. The width  33  of the plate nut  30  is narrower than the gap  22  between the inner surfaces  11  of the side walls  12  by a predetermined value as shown in  FIG. 4 . The predetermined value is from about zero point one (0.1) millimeters to about zero point three (0.3) millimeters. The nut hole  40  has a diameter from about one point five (1.5) to about one point nine (1.9) centimeters.  
      The plate nut  30  includes four ( 4 ) nut holes  40 .  
      The plate nut connector system  100  further includes two or more washer  45  for tightening the bolts  50 .  
      The plate nut  30  is adapted to the groove  18  formed by the bottom wall  14  and the side walls  12 . The side wall  12  of the strut  10 ,  20  includes a flange  24  along the brim the groove  18 , and the flanges  24  on both sides face inwardly as shown in  FIG. 4  and  FIG. 6 .  
      In the second embodiment of the invention as shown in  FIG. 7 , the plate nut  30  is bent along the mid-line between the nut holes  40  on the hole-bearing surface  31  of the plate nut  30  by a predetermined angle  39 . The predetermined angle  39  is from about twenty five (25) to about one hundred fifty five (155) degrees.  
      In a third embodiment of the invention as shown in  FIG. 8 , the plate nut  30  is bent along the mid-line on the plank surfaces  32  of the plate nut  30  by a predetermined angle  49 . The predetermined angle  49  is from about twenty five (25) to about one hundred fifty five (155) degrees. The plate nut  30  is from about eight (8) to about twelve (12) millimeters thick, the length of each bent wing  35 ,  36  from about eight (8) to about twelve (12) centimeters, and the width of each bend wing  35 ,  36  approximately two (2) millimeters shorter than the gap  22  between the two side walls  12  of the struts  10 ,  20 . The nut hole  30  has a diameter from about one point five (1.5) to about one point nine (1.9) centimeters.  
      While the invention has been shown and described with reference to different embodiments thereof, it will be appreciated by those skilled in the art that variations in form, detail, compositions and operation may be made without departing from the spirit and scope of the invention as defined by the accompanying claims.