Patent Publication Number: US-6905106-B2

Title: Tapered pin for poured concrete wall form panels

Description:
This is a divisional of U.S. patent application Ser. No. 09/892,050, filed Jun. 26, 2001, now U.S. Pat. No. 6,691,976, which in turn claimed the benefit of U.S. Provisional Patent Application Ser. No. 60/214,338, filed Jun. 27, 2000, each of which is hereby incorporated by reference in its entirety. 

   BACKGROUND OF THE INVENTION 
   This invention relates to poured concrete wall forms, and more particularly, to connecting hardware for panels coupled together and used to construct the concrete wall form. 
   It is well known in the art to use prefabricated reusable panel units to construct a wall form for a poured concrete wall. The hardware associated with such panels connects the panels to one another to form the wall form. 
   Typically, each panel has a marginal frame projecting rearwardly from a back face of the panel to include a flange along the spaced side edges of the panel. The flanges are adapted to be positioned in an edge to edge relationship with the flange of an adjacent panel to construct a concrete wall form. Holes in the flanges of the adjacent panels can be aligned to receive therethrough the shank of a pin or a bolt. The bolt or pin may pass through the ends of tie-rods and are held in position commonly by wedges which are driven though a slot in the shank of the bolt or pin. As the wedges are driven in place, the abutting flanges of the adjacent panel units are drawn together. The pins and wedges constitute a simple mechanism for effectively coupling the panels together. The pins and wedges can be removed from the panels during the dismantling of the wall form by knocking out the wedges from the slots and sliding the pins from their holes to release the adjacent panel units and the pin from the tie-rod now embedded in the cured concrete. 
   In the construction of a concrete wall form, a large quantity of hardware is necessary to connect the numerous panels together. Each pair of adjacent panels is typically connected together by multiple, typically three to four, pin and wedge combinations. After the spaced wall forms are constructed and the concrete poured, the panels and pins attaching the panels experience significant hydrodynamic forces resulting from the pouring and curing of the concrete. The large forces experienced by the pins often make it difficult to remove the pins from the flanges of the adjacent panels once the concrete is cured. Commonly, a hammer or other tool is required to dislodge the wedge from the pin and to dislodge the pin from the flanges of the adjacent panels. 
   One of the primary purposes of the tie rods extending between the spaced wall forms is to maintain the position of the wall forms relative to one another during the pouring and curing of the concrete. As a result, the tie rods exert a significant amount of force on the pins they are attached to in order to hold the panels in place during the concrete pouring and curing. Therefore, the pins are often very difficult to remove from the flanges and to release from the attached tie rods. 
   Furthermore, the wall forms are commonly constructed in excavated areas such as ditches and trenches when preparing the wall form for a poured concrete wall in a residential basement or below ground floor of a commercial building. As such, the work space for constructing and disassembling the wall form and for the workers to maneuver and manipulate the associated hardware is extremely tight and limited. Therefore, the installation and removal of the pins and wedges is even more difficult and problematic. 
   Therefore, a need exists in the industry for an attachment mechanism for coupling adjacent panels and constructing a poured concrete wall form which is easily and conveniently installed and most importantly disassembled by the workers in the field. Such an attachment segment must be robust enough to withstand the concrete forces, economical to manufacture and preferably be compatible with existing wall form panels. 
   SUMMARY OF THE INVENTION 
   These and other objectives of the invention have been attained by an improved pin for coupling adjacent panels together to form a concrete wall form. The pin according to a presently preferred embodiment of this invention is adapted to be used with a wedge as is well known in the art. The wedge typically has a tapered configuration such that a broad end of the wedge tapers to a more narrow end of the wedge. The pin has an enlarged head and an elongated shank extending from the head to a rounded tip or blunt end opposite the head. A generally rectangular through slot to receive the wedge is included in the shank proximate the end and extends perpendicularly to a longitudinal axis of the pin. 
   Advantageously, the pin according to this invention includes a tapered region to facilitate the removal of the pin from the tie rod and flanges of the adjacent panels during disassembly of the wall forms after the concrete has cured. In certain embodiments of this invention, the tapered region includes two portions. A first portion proximate the head of the pin tapers from a large diameter adjacent the head toward a smaller diameter at a juncture with a second tapered portion. The diameter of the second tapered portion at the juncture is greater than the diameter of the pin proximate the tip end. As a result of the tapered region and other features of the pin according to this invention, once the wedge is removed from the slot, the removal of the pin is easier than with known pin designs because of the tapered region. The taper on the shank of the pin promotes the release of the pin from the holes in the flanges of the panels and the removal of the shank of the pin from the hole in the tie rod. Because of the tapered region, movement of the pin from a larger diameter or circumferential portion of the shank toward a smaller diameter or circumferential portion is advantageously easier than the purely cylindrical-shaped, non-tapered shank of known pins. 
   In constructing the wall form using the pin and wedge combination according to this invention, adjacent panels are positioned with the associated holes in adjacent flanges being aligned so that the pin can be inserted through the first flange until the head contacts one of the flanges. A tie-rod is slipped onto the pin and the adjacent panel is joined by inserting the narrow end of the wedge into the slot to secure the pin in the holes and releasably couple the panels together. 
   As a result, the pin according to this invention provides a simple and cost effective attachment mechanism to facilitate easier removal of the present pin compared to previously known pins. The pin and wedge combination of this invention can be used with currently existing panel designs utilizing existing wedges without replacing an entire inventory of hardware and is robust to withstand the concrete pouring and curing forces while still being more easily removed than known pin designs. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The objectives and features of the invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
       FIG. 1  is a perspective view of one embodiment of a pin according to this invention; 
       FIG. 2  is a side elevational view of the pin of  FIG. 1 ; 
       FIG. 3  is a top plan view of the pin of  FIG. 1  with the bottom view being a mirror image thereof; 
       FIG. 4  is a right side view of the pin of  FIG. 1 ; 
       FIG. 5  is a cross-sectional view of a pin according to this invention being assembled with a tie rod, wall form panels and wedge for constructing a concrete wall form; and 
       FIG. 6  is a cross-sectional view of the assembled hardware, including the pin, according to this invention, securing adjacent wall form panels together. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , a presently preferred embodiment of a pin  10  according to this invention is shown. The pin  10  includes an enlarged disk shaped head  12  and an elongated shank  14  extending from the head  12 . A rounded end  16  opposite the head  12  terminates in a blunt tip  18 . The shank  14  includes a tapered region  20  which in one embodiment includes a first portion  21  adjacent the head  12  and a second portion  22  adjacent the tip end  16 . The first and second portions meet at a juncture  26 . The pin  10  also includes a generally oval through slot  24  in the shank  14  proximate the end  16  and extending perpendicularly to a longitudinal axis of the pin  10 . 
   Referring to  FIGS. 5 and 6 , the shank  14  of the pin  10  is sized for insertion through a hole  34  in a flange  36  of a panel  38  used for constructing a concrete wall form. The hole  34  in the flange  36  is aligned with a similarly configured hole  34   a  in the flange  36   a  of an adjacent panel  38   a . The flanges  36 ,  36   a  may include a bushing (not shown) seated in the holes  34 ,  34   a  and the diameter of the opening in the bushing is less than the diameter of the disk shaped head  12  on the pin  10  thereby preventing the head  12  from passing through the holes  34 ,  34   a  in the flanges  36 ,  36   a.    
   As is well known in the art, a tie-rod  42  having hole  44  proximate an end thereof is positioned between the panels  38 ,  38   a  of the concrete wall form to maintain the spacing between opposed panels (not shown) forming a cooperating wall form (not shown). The flanges  36 ,  36   a  may include a notch or cut-out  46  sized and configured to accommodate the tie-rod  42  seated therein so that the flanges  36 ,  36   a  of the adjacent panels  38 ,  38   a  can be juxtaposed in face to face abutting relationship. 
   A wedge  48  according to a presently preferred embodiment of this invention is well known in the art and includes a generally planar piece of steel or other appropriate metal which is dimensioned to fit within the slot  24  in the pin  10 . The wedge  48  has a tapered configuration so that a narrow end  50  of the wedge  48  passes into and through the slot  24  and a broad end  52  of the wedge  48  is wider than the slot  24  and is thereby prevented from passing through the slot  24 . One presently preferred embodiment of a wedge  48  which could be used in this invention is disclosed in U.S. Provisional Patent Application Ser. No. 60/035,666 filed Jan. 21, 1997, which is hereby incorporated by reference. In assembling a concrete wall form according to this invention, the adjacent panels  38 ,  38   a  are positioned with the respective holes  34 ,  34   a  in the flanges  36 ,  36   a  being generally aligned and the flanges  36 ,  36   a  initially being spaced. The pin  10  is inserted into the hole  34  in the flange  36  by the worker so that the head  12  contacts the bushing and is prevented from passing through the hole  34  as shown in  FIGS. 5-6 . 
   After the pin  10  is inserted in the flange  36  and the tie-rod  42  is fitted over the shank  14  of the pin  10 , the adjacent panel  38   a  is moved into abutting relationship with the panel  38  so that the shank  14  of the pin  10  projects through the aligned hole  34   a . The pin  10  may be retained in position during assembly of the wall form by a spring biased ball (not shown) as disclosed in U.S. Pat. No. 5,802,795 which is assigned to the assignee of this invention and hereby incorporated by reference entirely. Lastly, the narrow end  50  of the wedge  48  is inserted into the slot  24  and hammered or forced into place thereby releasably coupling and binding the adjacent panels  38 ,  38   a  and tie-rod  42  together and forming the concrete wall form. Disassembly of the wall form is easily accomplished according to this invention by dislodging the wedge  48  from the slot  24  and pushing the pin  10  out of the holes  34 ,  34   a.    
   The tapered region  20  on the pin  10  assists in the easy removal of the pin  10  from the holes  34 ,  34   a . The forces exerted on the panels  38 ,  38   a  by the poured concrete often make it difficult to extract known pin designs from the holes  34 ,  34   a . Due to the slope of the tapered region  20 , the binding forces generated by the concrete acting on the pin  10  are more quickly relieved as the pin  10  is withdrawn. 
   In one presently preferred embodiment of this invention, the pin  10  is 4140 steel finished with a black oxide having a Rockwell C hardness of 40-45. The head  12  of the pin  10  has a diameter of approximately 0.87 inches and the diameter of the shank  14  adjacent the head  12  is approximately 0.65 inches. The overall length of the pin  10  is preferably about 2.45 inches and the through slot  24  measures approximately 0.165 inches by 1.0625 inches in a generally oval configuration with a radius of about 0.083 inches at each end of the slot  24 . The end of the slot  24  adjacent the head  12  is spaced approximately 0.781 inches from the head  12 . 
   In one embodiment, the tapered region  20  extends a substantial portion of the length of the shank  14 . In a further embodiment, the tapered region  20  includes the first and second portions  21 ,  22 . The first portion  21  begins adjacent the head  12  and extends approximately 1.185 inches. The taper of the first portion  21  is relatively slight and preferably on the order of 0.65 inches to 0.63 inches. The taper of the second portion  22  is more significant and is on the order of 0.125 inches preferably. Generally, it is advantageous to have the tie-rod  42  seated on the tapered region  20  of the shank  14  of the pin  10  ( FIG. 6 ) to facilitate the removal of the tie-rod  42 . The tapered region  20  promotes the withdraw of the pin  10  from the hole  44  of the tie-rod  42  and, likewise, the withdraw of the pin  10  from the holes  34 ,  34   a  in the flanges  36 ,  36   a  of the adjacent wall form panels. 
   While presently preferred embodiments of the pin  10  are shown with the tapered region  20  extending the entire length of the shank  14 , it is within the scope of this invention that the tapered region extends only a portion of the shank while still providing the above-described benefits. Moreover, the embodiments disclosed herein reveal that the tapered region of the shank extends entirely around the circumference of the pin while other arrangements and pin designs are well within the scope of this invention in which the tapered region extends over only a portion of the circumferential region of the shank of the pin. Moreover, while pins are commonly used with wedges in the industry, embodiments of the pin shown herein include a slot to accommodate a wedge; whereas, alternative pin designs are readily encompassed within the scope of this invention which do not use a wedge for securing the pin during assembly of the wall form. These and other additional embodiments are likewise encompassed within the scope of this invention. 
   From the above disclosure of the general principles of the present invention and the preceding detailed description of a preferred embodiment, those skilled in the art will readily comprehend the various modifications to which this invention is susceptible. Therefore, we desire to be limited only by the scope of the following claims and equivalents thereof.