Abstract:
A metal reshore post for concrete forming systems is described. The reshore post includes an end plate to which is releasably attached a leaf spring. Clips formed in the leaf spring engage corresponding notches in the end plate. The spring retains the reshore post in its upright position during installation and prevents the reshore post from falling over upon release of the load.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The invention relates generally to concrete form apparatus and, more specifically, to spring assembly of a reshore post component of concrete form systems that retains the reshore post in its upright position upon unloading of the reshore post during disassembly of the concrete forms.  
         [0002]     Concrete forming apparatus is in wide use in the construction of buildings, bridges, and other concrete structures. A common system for forming concrete structures uses a plurality of modular form components that are adapted to be assembled into a wide variety of configurations to conform to virtually any architectural requirement. Such forming apparatus components are typically made of metal so that they are strong enough to support the heavy weight of poured concrete and durable so that the components can be reused many times.  
         [0003]     In the construction of concrete structures, for example multi-story buildings, it is common to pour floors in succession, starting at the bottom. Accordingly, concrete forming apparatus for pouring upper floors typically must be supported on the next lower floor. Economy and time of construction, however, often demands that the upper floors be poured before the concrete in the floors below has fully set. The concrete in the floor immediately below the floor being poured may not, therefore, have cured or hardened sufficiently to be strong enough to support the load of the concrete forming apparatus and plastic concrete used to form the floor being poured. It is common practice in such situations to insert shore posts below the insufficiently hardened floor or slab to distribute the load to one or more lower floors. The shore posts inserted below the partially hardened floors are generally referred to as reshore posts or just reshores. In typical applications there may be two or three levels of reshores below the shores supporting the fresh concrete.  
         [0004]     After the new slab of fresh concrete has cured sufficiently, workers remove the shore posts and strip the formwork they supported. This removes the load on the reshore posts below. In some situations, the removal and stripping operation will cause a complete release of the reshore post, allowing it to fall over. This, of course, presents a risk of injury to workers in the area of the reshore posts. In the case of wood reshore posts, to prevent the reshores from being released, it is known to nail a leaf spring to the top of the reshore post. Even upon release of the load on the reshore post, the spring remains in a degree of compression and continues to hold the reshore post upright. Unfortunately, no spring systems are in use with metal reshore posts because of the difficulty of attachment to the metal. Accordingly, there is needed a spring assembly for use with metal reshore posts that will hold them in their upright position when the load is released.  
       SUMMARY OF THE INVENTION  
       [0005]     The preferred embodiment of the present invention consists of a spring assembly of a metal reshore post used in concrete forming apparatus that will hold the reshore post in its upright position even after the load on the reshore post has been released. The assembly includes a spring that is releasably attached to an end plate secured to an end of the reshore post. The spring has a pair of clips that engage notches in the end plate to releasably secure the spring to the end plate. A variety of end plates may be used provided that appropriately spaced notches are formed in the plate. In a preferred embodiment, an end plate attached to what is most often the bottom end of the reshore post is of a different configuration from the end plate attached to the other end of the reshore post. The difference in configurations allows the reshore post to be used in both orientations in order to adapt to a larger variety of heights between floors.  
         [0006]     An object of the present invention is to provide a spring assembly for metal reshore posts of concrete forming apparatus that continues to support the reshore post in an upright position after release of a load on the reshore post.  
         [0007]     Another object of the present invention is to provide a spring assembly for metal reshore posts of concrete forming apparatus that may be releasably attached to either end of the reshore post.  
         [0008]     These and other objects will be understood by those skilled in the art upon a review of this specification, the associated figures and the appended claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is an elevational view of a reshore post representing a preferred embodiment of the present invention.  
         [0010]      FIGS. 2   a - d  are schematic representations of four typical construction phases of a multi-story concrete structure showing the use of shores and reshores.  
         [0011]      FIG. 3  is an enlarged perspective view of an end plate of a preferred embodiment of the present invention.  
         [0012]      FIG. 4  is an enlarged perspective view of an end plate of an alternative preferred embodiment of the present invention.  
         [0013]      FIG. 5  is an enlarged perspective view of leaf spring of a preferred embodiment of the present invention.  
         [0014]      FIG. 6  is an enlarged view of the upper end of the reshore post of  FIG. 1  showing the leaf spring attached to an end plate. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0015]     Illustrated in  FIG. 1 , generally at  10 , is a reshore post representing a preferred embodiment of the present invention. The reshore post  10  includes an outer telescoping tube  12 , an inner telescoping tube  14 , a bottom end plate  16 , a top end plate  18 , and a leaf spring  20 . The shore post  10  may be adjusted in length by telescopic movement of the inner tube  14  inside the outer tube  12 . The shore post  10  may be set at a plurality of adjusted lengths by use of a pin  22  that is inserted into a pair of diametrically opposed holes  24  in the outer tube  12  and a selected pair of a plurality of holes  26  in the inner tube  14  spaced at a regular interval. Fine adjustment of the length of the shore post  10  is made by rotation of a threaded linkage member  28 .  
         [0016]     The reshore post  10  is used in the construction of concrete structures, for example multi-story concrete buildings. Shore posts are also typically used. Shore posts may take a large variety of configurations. For the purposes of this specification, suitable shore posts may be identical to the reshore post  10  with the exception that the leaf spring  20  is not used. Rather, the top end plate  18  is used to secure a different component of formwork, such as a drop head, support beam, form panel, or the like. In a typical construction cycle for a multi-story concrete building, a floor  30  is formed using reshore posts  10  supporting two lower stories and shore posts  32  and formwork  34  on which the slab of the floor  30  will be formed ( FIG. 2   a ). Once the fresh concrete has hardened sufficiently to carry its own weight, the shores  32  and formwork  34  are removed ( FIG. 2   b ). Frequently, the fresh concrete slab  30  will deflect or sag under its own weight. To pour the next floor, it will be necessary to install shore posts and formwork on the most recently poured floor slab  30 , the strength of which may not be sufficient to support the load that will be imposed. To support further the most recently poured floor slab  30 , the reshore posts  10  are cycled by removing them from two floors below ( FIG. 2   c ) and installing them on the floor beneath the most recently poured floor  30  ( FIG. 2   d ).  
         [0017]     It is generally recommended that the reshore posts  10  be installed snugly under the slab or floor to be supported but relatively load free. Accordingly, the reshore posts  10  are adjusted to the approximate length that will allow the reshore  10  to be stood upright in position by use of the pin  22  in association with aligned pairs of holes  24  and  26 , as described above. Once positioned, the height may be finely adjusted by turning of the threaded linkage member  28  to bring the leaf spring  20  into contact with the bottom of the floor to be supported and compressed sufficiently to hold the reshore post  10  in its upright position. Upon installation of the shore posts  32 , formwork  34 , and plastic concrete for the next story, the floor  30  is expected to deflect, further compressing the spring  20  until, most commonly, the floor  30  will be supported effectively on the top end plate  18 .  
         [0018]     When the most recent floor has set sufficiently to support its own weight, the shores  32  and formwork  34  are stripped. This will release the load from the reshores  10  as the floor  30  returns to its un-deflected position. The spring  20  will retain compressed contact with the bottom of the floor  30  throughout and so continue to hold the reshore post  10  in its upright position.  
         [0019]     The top end plate  18  of a preferred embodiment has a generally rectangular shape ( FIG. 3 ). Notches  36  and  38  are formed in opposite sides of the end plate  18 . The bottom end plate  16  is substantially U-shaped in cross section, having a web  40  that is similar in shape to the top end plate  18 , and a pair of flanges  42  and  44  formed on opposite sides of the web  40  ( FIG. 4 ). The bottom end plate  16  is formed of a plate of steel that is bent to form the web  40  and flanges  42 ,  44 . Rectangular holes  46  and  48  formed at the juncture of the web  40  and the flanges  42  and  44 , respectively, form notches  50  and  52  upon bending of the bottom end plate  16 .  
         [0020]     The spring  20  of a preferred embodiment includes a flat web section  54  from either side of which extend outwardly and upwardly a curved spring section  56  and  58 . Spring clips  60  and  62  are formed at opposite ends of the web section  54 . The clips  60  and  62  include a modified S- or ogee-shaped end portion  64  and  66 , respectively. In use, the spring  20  is releasably attached to the top end plate  18  by aligning spring clips  60 ,  62  with the notches  36 ,  38  and pressing to flex the spring clips  60 ,  62  outwardly so that they slide past the notches  50 ,  52  and bring the web section  54  into contact with the end plate  18 . The end portions  64  and  68  of the spring clips  60 ,  62  engage the underside of the top end plate  18  to retain the spring  20  on the top end plate  18 . If desired, the spring  20  can be readily removed by pulling outwardly on the spring clips  60  and  62 . While the reshore post  10  is most commonly used with the top end plate  18  at the top, there are circumstances where it is advantageous to orient the reshore post  10  with the bottom end plate  16  at the top. Accordingly, in a manner similar to that discussed above with respect to the top end plate  18 , the spring  20  may be releasably attached to the bottom end plate  16  by use of the notches  50  and  52 .  
         [0021]     The foregoing description and drawings comprise illustrative embodiments of the present inventions. The foregoing embodiments and the methods described herein may vary based on the ability, experience, and preference of those skilled in the art. Merely listing the steps of the method in a certain order does not constitute any limitation on the order of the steps of the method. The foregoing description and drawings merely explain and illustrate the invention, and the invention is not limited thereto, except insofar as the claims are so limited. Those skilled in the art that have the disclosure before them will be able to make modifications and variations therein without departing from the scope of the invention.