Patent Publication Number: US-2005120657-A1

Title: Form system wall tie and methods for making and using the same

Description:
TECHNICAL FIELD  
      The present invention relates to concrete form systems, and more particularly, to concrete form system wall ties and methods for making and using the same.  
     BACKGROUND OF THE INVENTION  
      Concrete form systems have been well known in the prior art for a considerable period of time. Typically, such systems are used to form concrete into desired shapes and in desired locations by holding concrete stable while it cures. These systems are particularly useful in forming walls, whether freestanding or placed adjacent another surface, such as a land cut.  
      Generally, concrete form systems use pre-formed surfaces, such as planar surfaces or specifically curved surfaces that are held in stable position, and against the hydrostatic pressure of the concrete, by means of a variety of fixtures to mold the concrete during the curing process.  
      Included in these fixture are objects called concrete form ties, which are tension members used to connect opposing mold surfaces (such as form panels) and resist the hydraulic pressure of the liquid concrete during pouring. Concrete form ties are also sometimes required to hold form panels apart during erection. Concrete form ties are usually made from medium- or high-carbon steel, although there are also some fiberglass concrete form ties.  
      There are a great variety of form panels in use. The oldest and simplest type is simply a sheet of plywood (of standard dimensions or cut down to convenient size), with holes drilled at appropriate intervals in its length and breadth for ties to pass through. In one form, wire ties with loops formed on the ends are passed through the drilled holes; steel rods are threaded through the loops of a row of ties, transferring the hydrostatic load to the ties and stiffening the plywood between adjacent ties.  
      In another variation, wales may be used to stiffen the plywood and spread the load. These are often 2×4 or 2×6 pieces of lumber. The use of wales can reduce the number of ties required for a given area of form, with a consequent increase in the tensile load per tie. The ties in this variation often take the form of round wire rods, with upset ends and are commonly called “snap ties”, or “button-head” ties. They may be secured to a double set of walers by a slotted wedge or to a single waler by a slotted flat cam arrangement mounted on a bracket. The tensile load rating for these ties is typically from 2250 to 3350 lbs.  
      Systems were developed to minimize the use of wales and provide a convenient way to erect and connect form panels on the job site. One type, such as that made by the Symons Corporation of Des Plaines, Ill., uses a thin ({fraction (1/2)}-inch) plywood panel reinforced by a rolled steel framework. The ties pass through notches cut into the surrounding framework and usually take the form of round wire rods with the ends formed into loops with tensile load ratings typically from 2250 to 3000 lbs., or flat strips of sheet steel with tensile load ratings typically from 3000 to 3500 lbs.  
      In another common system (the so-called “1-{fraction (1/8)}” plywood system), thicker plywood (typically 1-{fraction ( 1 / 8 )} inches thick) is used and the steel framework is replaced by horizontal flat bars of steel, typically {fraction (1/4)} inch by 2 inches. These flat bars have attached pivoting latches for interconnecting the form panels and securing the ties. The ties for this system are typically flattened wire with notches pressed into the wire near the ends to engage the swinging latches and other hardware and have tensile load ratings of about 2500 lbs.  
      In yet another system, an entire panel is fabricated from aluminum, and the ties take the form of flat strips of carbon steel with a tensile load rating of about 3750 lbs.  
      In all of these form systems, the tie becomes embedded in the concrete wall that is being formed. After the concrete has set, the means of attachment to the tie are removed (rod, wedge, latch, or whatever) and the form panels removed. This leaves a portion of the tie protruding from the surface of the cured concrete. The ties are usually designed to be broken at “breakbacks”, by bending or twisting, either flush with the surface of the wall, or at some point below the surface.  
      There is still another type of tie that is made from an interchangeable set of components attached to each other by threaded connections. The elements around which these tie assemblies are built are commonly called “coil ties”, and are made by joining 2 or more wire rods to tightly-wound wire coils on either end. These coils are therefore capable of threading onto to specially made threaded rod. This design allows for a great deal of versatility in making connections to a variety of form panels, waler configurations, anchors, weld-on attachments, and so forth.  
      For instance, to attach a single form panel to an existing wall (for a “one-sided” pour) an anchor can be placed in a drilled hole in the wall. A length of coil rod is threaded into the anchor and a coil tie then threaded onto the rod. Alternatively, a length of coil rod can be epoxied into the hole, or a conventional toggle tie can be used. Into the other end of the coil tie is threaded an element which is appropriate for the type of form panel, or the means of attachment desired. Similarly, a tie of any length can be constructed (and field-adjusted) by varying the length of coil rod, coil tie, or both. The tensile load rating of the coil ties depends largely on the size of the coil rod and varies from about 4500 lbs. to 18,000 lbs.  
      However, this versatility has come at the expense of economy, and, in some cases, ease-of-use. For some applications, it is more economical and/or more convenient, to use a tie element that in one piece combines a form-connection element (usually of the breakable kind) with a coil-tie element (for connection to the whole range of elements standard to that system). In the case of one-sided forming, the convenience of using a standard breakable tie end to engage the form panels is often desirable.  
      The case of creating an adjustable-length tie from standard parts in a conventional system illustrates this point. Form-connection elements that are made from pieces of threaded rod having flattened, slotted ends make the connection to the form panels. Each of these form-connection elements is connected to an individual coil tie and a length of coil rod holds the two coil ties together with the appropriate spacing. For ease of removal, the form-connection elements must be greased before the concrete is poured. They are then removed by unscrewing with a wrench after the forms have been stripped, leaving a large hole in the concrete wall that must be filled.  
      Another wall tie that is used in the industry is the coil combination tie, such as that made by the Universal Form Clamp Company, of Chicago, Ill. The coil combination tie combines a form-connection element (such as a button head or a loop) at one end with a wire coil at the other end. The form-connection element is attached directly to one side of the wire coil, while a shorter piece of rod connects between the form-connection element and the opposite side of the wire coil. While the coil combination tie reduces the complexity of the hardware needed to form an adjustable tie, it is difficult to use in practice when doing one-sided pours because of its asymmetry since the hole for the anchor must be placed off-center relative to the location of the hole in the form. In addition, the asymmetry leads to an imbalance in the tension on the two opposing sides of the wire coil.  
      It is, therefore, desirable to have a form system wall tie that symmetrically combines a form-connection element at one end with a wire coil at the other end.  
     SUMMARY OF THE INVENTION  
      In accordance with a first aspect, the invention is a wall tie for holding a form wall in a stationary position relative to a fixed point. The wall tie includes an elongated tie rod, a plurality of struts, and an attachment member. The elongated tie rod has a longitudinal axis and a first portion and a second portion. The first portion is adapted for placement through the form wall and the second portion has a first attachment surface. The first and second portions are longitudinally displaced from one another along the longitudinal axis.  
      The plurality of struts have a first attachment portion and a second attachment portion, the first attachment portion is attached to the first attachment surface of the tie rod and extends away from the tie rod in a direction that is generally parallel to the longitudinal axis. The attachment member is located on the longitudinal axis. The second attachment portion of the plurality of struts is attached to the attachment member.  
      According to a second aspect, the invention is a wall tie assembly for holding two form walls in a stationary position relative to one another. The wall tie assembly includes two wall ties. Each wall tie includes an elongated tie rod, a plurality of struts and an attachment member. The elongated tie rod has a longitudinal axis and a first portion and a second portion. The first portion is adapted for placement through the form wall and the second portion has a first attachment surface. The first and second portions are longitudinally displaced from one another along the longitudinal axis. The plurality of struts has a first attachment portion and a second attachment portion. The first attachment portion is attached to the first attachment surface of the tie rod and extends away from the tie rod in a direction that is generally parallel to the longitudinal axis. The attachment member is located on the longitudinal axis. The second attachment portion of the plurality of struts are attached to the attachment member.  
      The two wall ties are placed in opposition to one another along the longitudinal axis.  
      The wall tie assembly also includes a longitudinal extension member that is connected to the second attachment portion of the plurality of struts of each of the wall ties.  
      According to a third aspect, the invention is a method for making a wall tie for holding a form wall in a stationary position relative to a fixed point. The method includes the steps of a) forming an elongated tie rod having a longitudinal axis. The tie rod has a first portion and a second portion. The first portion is adapted for placement through the form wall and the second portion has a first attachment surface. The first and second portions are longitudinally displaced from one another along the longitudinal axis.  
      The method also includes the steps of b) forming a plurality of struts having a first attachment portion and a second attachment portion and c) attaching the first attachment portion of each of the plurality of struts to the first attachment surface of the tie rod so that it extends away from the tie rod in a direction that is generally parallel to the longitudinal axis.  
      The method further includes the steps of d) forming an attachment member, e) locating the attachment member on the longitudinal axis, and f) attaching the second attachment portion of the plurality of struts to the attachment member.  
      According to a fourth aspect, the invention is a method for making a wall tie assembly for holding two form walls in a stationary position relative to one another. The method includes the step of a) forming two wall ties, including, for each wall tie, the step of a 1 ) forming an elongated tie rod having a longitudinal axis. The tie rod has a first portion and a second portion. The first portion is adapted for placement through the form wall. The second portion has a first attachment surface. The first and second portions are longitudinally displaced from one another along the longitudinal axis. Step a) further includes the steps of a 2 ) forming a plurality of struts having a first attachment portion and a second attachment portion, a 3 ) attaching the first attachment portion to the first attachment surface of the tie rod so that it extends away from the tie rod in a direction that is generally parallel to the longitudinal axis, a 4 ) forming an attachment member, a 5 ) locating the attachment member on the longitudinal axis, and a 6 ) attaching the second attachment portion of the plurality of struts to the attachment member.  
      The method further includes the steps of b) placing the two wall ties in opposition to one another along the longitudinal axis, c) forming a longitudinal extension member, and d) connecting the extension member to the second attachment portion of the plurality of struts of each of the wall ties.  
      According to a fifth aspect, the invention is a wall tie for holding a form wall in a stationary position relative to a fixed point. The wall tie includes an elongated tie rod means, a plurality of strut means, and an attachment member means.  
      The elongated tie rod means has a longitudinal axis, a first portion for placing through the form wall and a second portion for attachment to a surface. The first and second portions are longitudinally displaced from one another along the longitudinal axis.  
      The plurality of strut means has a first attachment portion for attaching each of the plurality of struts to the first attachment surface of the tie rod means so that it extends away from the tie rod means in a direction that is generally parallel to the longitudinal axis.  
      The attachment member means is located on the longitudinal axis for attaching the second attachment portion of the plurality of struts to the attachment member means.  
      According to a sixth aspect, the invention is a wall tie assembly for holding two form walls in a stationary position relative to one another. The wall tie assembly includes two wall ties. Each wall tie includes an elongated tie rod means, a plurality of strut means, and an attachment member means.  
      The elongated tie rod means has a longitudinal axis and a first portion and a second portion. The first portion is for placing through the form wall and the second portion has a first attachment surface. The first and second portions are longitudinally displaced from one another along the longitudinal axis.  
      The plurality of strut means has a first attachment portion and a second attachment portion for attaching the first attachment portion to the first attachment surface of the tie rod means so that it extends away from the tie rod means in a direction that is generally parallel to the longitudinal axis.  
      The attachment member means is for locating the attachment member means on the longitudinal axis and for attaching the second attachment portion of the plurality of strut means to the attachment member means.  
      The two wall ties are placed in opposition to one another along the longitudinal axis.  
      The wall tie assembly also includes a longitudinal extension member for connecting the extension member to the second attachment portion of the plurality of struts of each of the wall ties.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a view of a first embodiment of the invention.  
       FIG. 2  is a view, from the same perspective as the view of  FIG. 1 , showing copies of the first embodiment of the invention after they have been installed.  
       FIG. 3  is a view of copies of a second embodiment of the invention after they have been installed.  
       FIG. 4  is a view of a third embodiment of the invention.  
       FIG. 5  is a view, from the same perspective as the view of  FIG. 4 , of copies of a fourth embodiment of the invention after they have been installed.  
       FIG. 6  is a diagram showing the assembly of the first embodiment of the invention.  
       FIG. 7  is a diagram showing the assembly of the second embodiment of the invention.  
       FIG. 8  is a diagram showing the assembly of a third embodiment of the invention.  
       FIG. 9  is a diagram showing the assembly of a fourth embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION  
       FIG. 1  is a view of a first embodiment of the invention. The wall tie  20  includes an elongated tie rod  22 , a plurality of struts  24 , and an attachment member  26 . The tie rod  22 , the plurality of struts  24  and the attachment member  26  are made from materials that can be permanently attached to each other, for example, by welding, although other method of attachment known to those skilled in the relevant arts could also be used. As shown in  FIG. 1 , the elongated tie rod  22  is a loop tie that has a longitudinal axis  28 , a first portion  30  intended for placement through a form wall, and a second portion  32  having a first attachment surface  34 . The first and second portions  30  and  32  are displaced from one another along the longitudinal axis  28 .  
      Each of the plurality of struts  24  has a first attachment portion  36  and a second attachment portion  38 . The first attachment portion  36  is attached to the first attachment surface  34  of the tie rod  22 , and extends away from the tie rod  22  in a direction  40  that is generally parallel to the longitudinal axis  28 .  
      The attachment member  26  is located on the longitudinal axis  28  and the second attachment portion  38  of the plurality of struts  24  is attached to the attachment member  26 . As illustrated in  FIG. 1 , the attachment member  26  takes the form of a coil formed from wire. If desired, each strut  24  in the plurality of struts can be separately attached to the elongated tie rod  22  and/or the attachment member  26 . Alternatively, all of the struts  24  could be attached to a piece that is, in turn, attached to either the tie rod  22  and/or the attachment member  26 .  
      Alternatively, the attachment member  26  can be a length of externally threaded rod.  
      As also shown in  FIG. 1 , the attachment member  26  is receiving a threaded member  42  that, in turn, is attached to an anchor  44 .  
       FIG. 2  is a view, from the same perspective as the view of  FIG. 1 , showing copies of the first embodiment of the invention after they have been installed. The tie rods  22  of the wall ties  20  are placed through respective holes  50  in the framework  52  that is intended to hold the concrete in place as it cures between the framework  52  and an already-existing structure  54 , such as a retaining wall. The anchors  44  have been placed and fixed in the holes  56  that have been formed in the structure  54 , in alignment with the holes  50  in the framework  52 . The anchors  44  serve as fixed points relative to which the framework  52  is held stationary. After fixing the anchors  44  in the holes  56 , the threaded members  42  are threaded into the anchors  44 . Then wall ties  20  are threaded onto the threaded members  42  and adjusted so that the framework  52  is held in the desired position relative to the structure  54 .  
      After the concrete has set, the framework  52  is removed.  
       FIG. 3  is a view of copies of a second embodiment of the invention after they have been installed. The second embodiment is similar to the first embodiment, except that the tie rods  22  are snap ties, as will be understood by those skilled in the relevant arts.  
       FIG. 4  is a view of a third embodiment of the invention. In this embodiment, a wall tie assembly  60  consists of two copies of the wall tie as described above in connection with  FIG. 1  and a longitudinal extension member  62  that threadably engages the two attachment members  26 .  
       FIG. 5  is a view, from the same perspective as the view of  FIG. 4 , of copies of a fourth embodiment of the invention after they have been installed. The tie rods  22  of the wall tie assemblies  60  extend through holes  64  that are formed in the two forms  66  that are being held in relative position by the wall tie assemblies  60 . The wall tie assemblies  60  have been individually adjusted to hold the forms  66  in the desired position. After the concrete has set, the framework  52  is removed and the tie rods  22  are broken off.  
       FIG. 6  is a diagram showing the assembly of the first embodiment of the invention. The struts  22  are bent to an offset shape so that, after assembly, they will touch both the tie rod  22  (a loop tie) and the attachment member  26  before they are attached to the tie rod  22  and the attachment member  26 .  
       FIG. 7  is a diagram showing the assembly of the second embodiment of the invention. As above, the struts  22  are bent to an offset shape so that, after assembly, they will touch both the tie rod  22  (a snap tie) and the attachment member  26  before they are attached to the tie rod  22  and the attachment member  26 .  
       FIG. 8  is a diagram showing the assembly of a third embodiment of the invention. As above, the struts  22  are bent to an offset shape so that, after assembly, they will touch both the tie rod  22  (a button-head tie) and the attachment member  26  before they are attached to the tie rod  22  and the attachment member  26 .  
       FIG. 9  is a diagram showing the assembly of a fourth embodiment of the invention. In this case, the wall tie  68  is shown to include a conventional strut  22 , a modified strut  70  and an attachment member  26 . Strut  70  has been modified by merging the shape of a conventional strut  22  with the shape of a tie rod (here, shown as a snap tie). Both the conventional strut  22  and the modified strut  70  are offset. The modified strut  70  is offset so that the centerline of the tie rod portion is aligned with the longitudinal axis  72  while the other end of the modified strut  70  is touching the attachment member  26 . The strut  22  is offset so that it can simultaneously touch both the tie rod end of the modified strut  70  and the attachment member  26 . After all of the pieces have been placed in touching abutment, they are welded.  
      While the foregoing is a detailed description of the preferred embodiment of the invention, there are many alternative embodiments of the invention that would occur to those skilled in the art and which are within the scope of the present invention. Accordingly, the present invention is to be determined by the following claims.