Abstract:
A device for compensating for the natural shrinkage of building materials includes a hinged expander mounted on an elongate base plate. The base plate includes a plurality of spaced apart teeth on each longitudinal end that define a notch between each pair of adjacent spaced teeth. The hinged expander included two leafs that are joined at an apex in a hinged relationship. Each leaf has an outer edge configured for receipt within a notch in the base plate. Apex is biased in a direction away from the base plate. The teeth prevent outward movement of the leaf edges while permitting inward movement. The base plate is securely fastened to a first building member. A fastener is longitudinally fixed relative to a second building member and the apex of the hinged expander but not fixed longitudinally relative to the base plate and first building member.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Application No. 62/312,514, filed Mar. 24, 2016, the entire content of which is hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    The disclosure relates generally to building structures, and more particularly to shrinkage compensation devices for building structures having wooden frames. 
         [0003]    In wood constructions, such as residences and smaller commercial buildings or hotels, the wood construction material naturally shrinks slightly over time. Shrinkage in lumber occurs as the moisture in the wood members evaporates causing the wood materials to constrict. Since only the wooden materials shrink (not fasteners or other metal components), the shrinkage of the building materials and the heavy load weight of building materials can result in an undesirable extra vertical clearance between levels and an overall loose structure. This phenomenon commonly causes the building to be susceptible to damage from uplift due to high winds or similar external forces. Thus, building compensation devices exist to restrain the building materials and prevent uplift. A typical system includes a series of elements: connectors at the roof to top of a wall, top of a wall to vertical studs, vertical studs between adjacent floors and to the foundation. In order to counteract upward loads from winds, the framing members may be anchored to the surface on which they are supported. On the ground level, anchor rods are typically sunk into a concrete foundation, and the bottom plate of the wall is bolted to the anchor rods. For levels built on top of the first level, straps or elongate fasteners are often used to anchor an upper level to the level below. 
         [0004]    While effective at anchoring upper levels to lower levels, coil straps have certain drawbacks, including being positioned on the exterior of a framed construction, requiring alignment of vertical studs on adjacent floors Shrinkage in lumber occurs as the moisture in the wood members evaporates causing the members to constrict. This constriction may result in buckling or bowing outward of the strap, as well as any siding or exterior covering of the framed construction. 
         [0005]    Compensation or take-up devices exist that allow a screw or similar elongate fastener to travel in one direction relative to a building level, while preventing the screw from traveling in the other direction exist for this reason. In practice, for example, a compensation device having a plate or similar element may be attached to the frame of an upper level of a building structure. An elongate fastener may be driven through the upper level frame with the distal end secured to the frame in the lower level. The compensation device in this example would allow the proximal end of the fastener (head) to travel upward relative to the top level frame, but prevent it from moving in the opposite direction. 
         [0006]    Shrinkage compensation devices are shown and described in the art, including devices that mechanically engage with threads in the proximal portion of the elongate fastener to maintain the fastener with a ratchet engagement. Other devices exist that employ a torsion spring that biases two threaded members in opposite rotational directions so that the device can expand but not contract, or vice versa, depending on the position within the building frame structure. These known devices carry several drawbacks, including that the required firm mechanical metal-on-metal contact with the threads in the former example provides resistance in the direction of travel and can leave the threading vulnerable to stripping, as well as the strength of the ratchet engagement being limited by the shallowness of the threading. The rotationally biased devices can be prone to malfunction due to complexity and typically require several distinct steps during installation, making them inconvenient. Thus, there is a need for a building shrinkage compensation device that is easy to install and reduces or omits all of the aforementioned drawbacks. 
       SUMMARY 
       [0007]    In an embodiment, a building shrinkage compensation device has an elongate base plate, a hinged expander and a bias member. The elongate base plate extends laterally from a first end to a second end. Both the first end and second end have a series of space teeth. The base plate defines a hole laterally between the opposite ends. The hinged expander includes a first leave and a second leaf. The first leaf has a first outer edge positioned between adjacent teeth in the base plate first end and the second leaf has a second outer edge positioned between adjacent teeth in the base plate second end. The first and second leafs are attached to each other at an apex opposite the outer edges in a hinged relationship. The apex defines an opening substantially laterally aligned with the base plate opening. The bias member biases the apex of the hinged expander away from the base plate. 
         [0008]    In another embodiment, a building frame structure has a first level vertically spaced from a second level. A shrinkage compensation device includes an elongate base plate and a hinged expander. The base plate extends laterally from a first end with a series of spaced teeth to a second end with a series of spaced teeth, and defines a hole laterally between opposite ends. The base plate is secured to the first level. A hinged expander has a first leaf with a first outer edge and second leaf with a second outer edge. The expander is mounted on the base plate with the first outer edge positioned between adjacent teeth in the base plate second end and the second outer edge positioned between adjacent teeth in the base plate second end. The first and second leafs are attaché to each other at an apex opposite the outer edges in a hinged relationship. The apex defines an opening substantially laterally aligned with the base plate opening. A bias member biases the apex of the hinged expander away from the base plate. An elongate fastener has a shank with a circumferential flange at a proximal position. The fastener is positioned with the shank extending through the hinged expander opening, base plate and top level with a distal portion securely engaged with the lower level and the flange tightly abutting the apex of the hinged expander. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Aspects of the preferred embodiment will be described in reference to the drawings, where like numerals reflect like elements: 
           [0010]      FIG. 1  depicts an embodiment of the building shrinkage compensation device installed on an upper level board in a collapsed position; 
           [0011]      FIG. 2  depicts the compensation device of  FIG. 1  in an expanded position; 
           [0012]      FIG. 3  is an enlarged view of the expanded compensation device of  FIG. 2  from a different angle; 
           [0013]      FIG. 4  is a side elevation view of an embodiment of the compensation device in a collapsed position at initial install; 
           [0014]      FIG. 5  is a side elevation view of the device of  FIG. 4  in an expanded position after shrinkage of building materials; 
           [0015]      FIG. 6  is a top elevation view of the device of  FIG. 5 ; 
           [0016]      FIG. 7  is an isometric perspective view of the device of  FIG. 5 ; 
           [0017]      FIG. 8  depicts a representative building structure with the disclosed compensation device installed in its initial collapsed position; 
           [0018]      FIG. 9  shows another embodiment of the disclosed hinged building shrinkage compensation device; and 
           [0019]      FIG. 10  shows another view of the device of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Among the benefits and improvements disclosed herein, other objects and advantages of the disclosed embodiments will become apparent from the following wherein like numerals represent like parts throughout the several figures. Detailed embodiments of a hinged building shrinkage compensation device are disclosed; however, it is to be understood that the disclosed embodiments are merely illustrative of the invention that may be embodied in various forms. In addition, each of the examples given in connection with the various embodiments of the invention which are intended to be illustrative, and not restrictive. 
         [0021]    Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases “In some embodiments” and “in some embodiments” as used herein do not necessarily refer to the same embodiment(s), though it may. The phrases “in another embodiment” and “in some other embodiments” as used herein do not necessarily refer to a different embodiment, although it may. Thus, as described below, various embodiments may be readily combined, without departing from the scope or spirit of the invention. 
         [0022]    In addition, as used herein, the term “or” is an inclusive “or” operator, and is equivalent to the term “and/or,” unless the context clearly dictates otherwise. The term “based on” is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of “a,” “an,” and “the” include plural references. The meaning of “in” includes “in” and “on. 
         [0023]    Further, the terms “substantial,” “substantially,” “similar,” “similarly,” “analogous,” “analogously,” “approximate,” “approximately,” and any combination thereof mean that differences between compared features or characteristics is less than 25% of the respective values/magnitudes in which the compared features or characteristics are measured and/or defined. 
         [0024]    With reference to the Figures, disclosed herein is a ratcheted building shrinkage compensation device  10  having an elongate base plate  12  and a hinged expander  14 . The base plate  12  has a plurality of spaced notches defined between a series of teeth  16  on opposite lateral ends. As shown, the hinged expander  14  is mounted on the base plate  12  with opposite edges  18   a  and  18   b  configured to engage within a notch on the respective lateral ends of the base plate. An expanded spring  20  extends between opposite ends of the hinged expander  14  and is connected to each leaf ( 14   a  and  14   b ) of the expander  14  to provide moderate inward biasing forces on each lateral end  18   a  and  18   b  of the of the expander  14 . Shown best in  FIGS. 2 and 3 , the base plate  12  defines a hole  21  in its body intermediate the respective series of teeth  16 . The hinged expander also defines a hole  22  at its apex between the respective leafs  14   a  and  14   b.  The expander  14  is mounted on the base plate  12  with the holes ( 21  and  22 ) aligned, thereby defining a passage for attachment of a take-up fastener  24  (i.e., screw or similar). 
         [0025]    Reference numeral  26  represents a generally flat or horizontal upper level of a building structure (frame or similar). Typically, the hinged expander  14  is initially mounted in its collapsed position on base plate  12  (i.e., with opposite leaf edges  18   a  and  18   b  engaged in an outer notch). Notably, in the collapsed position of the expander  14 , the tension spring  20  is actually extended or expanded with a higher degree of tension biasing the respective leafs  14   a  and  14   b  inward. The compensation device is secured to the surface of the upper level  26  via compressive forces of the proximal head  28  of the take-up fastener  24 , with the distal end of the fastener  24  secured to the lower building level  27 . As shown, the fastener  24  is positioned extending through the passage defined by the holes ( 21  and  22 ) in the apex of the hinged expander  14  and the base plate  12 , and driven through the upper level  26  and into the lower level  27  of the building frame, securing the upper level to the lower level (see full structure  FIG. 9 ) with the compensation device  10  compressed between the fastener head  28  and the upper level  26 . As shown, a flange  25  near the proximal head  28  of the take-up fastener tightly abuts the edges of the hole  22  of the hinged expander  14  when installed. At least a proximal portion of the shank of the take-up fastener  24  is unthreaded such that there is no threaded engagement between the take-up fastener  24  and any of the base plate  12 , hinged expander  14  and the upper level plank  26  (i.e., the proximal portion of the take-up fastener shank may pass freely through these elements). As shown in the representative structure  FIG. 9 , the take-up fastener  24  has threading  30  toward the distal end of the shank to engage securely into the lower level plank  27 . That is, the take-up fastener  24  and lower level plank  27  are rigidly attached at installation, while the take-up fastener  24  is longitudinally reciprocable relative to the upper level plank  26 . 
         [0026]    Once installed, the tension spring  20  provides an inward bias on the outer edges  18   a  and  18   b  of the leafs  14   a  and  14   b,  which in turn biases the head  28  of the take-up fastener longitudinally upward relative to the upper level  26  and attached base plate  12 . The upward bias on the take-up fastener head and secure attachment of the take-up fastener to the lower level plank  27  results in a relative bias on the upper level plank  26  and lower level plank  27  toward each other. While the tension spring  20  biases the opposite outer edges  18   a  and  18   b  of the leafs  14   a  and  14   b  inward, the surfaces and configuration of the notches and teeth  16  are such that outward movement of the edges  18   a  and  18   b  is prevented (i.e., only inward movement of the outer edges is permitted, thereby preventing further collapsing of the expander and take-up fastener head). As a result, the upper and lower levels can only be tightened relative to one another. 
         [0027]    As described above, over time, wood building materials may undergo natural shrinkage and constriction due to moisture loss, and settlement due to the weight of the materials. As shrinkage occurs, the upward bias on the take-up fastener head  28  keeps the upper level and lower level building materials in a tight arrangement relative to one another, resisting any upward loads on the building (from high winds, for example). The hinged expander  14  is allowed to “expand” upward via inward spring bias on the leaf edges  18   a  and  18   b  to maintain a tight system, while also being mechanically prevented from collapsing (by outward movement of the leaf edges  18   a  and  18   b ). Once the wood materials shrink enough that one or both of the leaf edges  18   a  and  18   b  pass from a notch inwardly over a tooth  16 , the edges are maintained in the adjacent notch and prevented from moving outward again. In this manner, the shrinkage compensation device  10  allows one-way motion of the base plate  12  and secured top level plank  26  relative to take-up fastener  24  and lower level  27  to compensate for the shrinkage of the wooden building materials to maintain the building structure in a tight arrangement. This one-way motion allows the wood building materials to constrict and the take-up fastener  24  to “take up” the lower level  27  relative to the upper level  26 , while preventing upward movement of the building materials under an upward force. The disclosed shrinkage compensation device  10  may be used to attach subsequent levels in a building structure to the adjacent level below; the device and described methods are not limited to a two-level structure. Furthermore, as skilled artisans will readily appreciate, the positioning of the expander  10  on the top surface of an upper level can be reversed to a bottom fastener driven upward into the upper level. 
         [0028]    The disclosed shrinkage compensation device  10  provides a simple installation and improved performance over known devices due to free passage of the proximal portion of the shank of the take-up fastener through the upper level plank and hole  21  in the base plate  12  (i.e., an absence of a metal-on-metal engagement with a take-up fastener threading during operation). In this manner, the compensation device  10  allows the proximal portion of the take-up fastener to travel freely upward relative to the upper level  26  as the wood building material shrinks. 
         [0029]    In an alternate embodiment, not depicted herein, the laterally-extended tension spring  20  is replaced by a bias member positioned between the base plate  12  and hinged expander  14  directly biasing the apex of the hinge upward. The bias member in this embodiment can be, for example, a compressed spring or another elastic material. 
         [0030]    Generally,  FIG. 1  depicts the device  10  with the hinged expander  14  in an initial collapsed position with outer leaf edges  18  in outer grooves in the base plate  12 . The depiction of  FIG. 1  represents the typical configuration at the point of initial installation of the device  10 .  FIG. 2  depicts the device  10  after shrinkage of the building materials has occurred and the spring  20  has contracted the outer leaf edges  18   a  and  18   b  inward causing upward movement of the apex of the hinged expander  14  and head  28  of the take-up fastener  24  relative to the base plate  12  and upper level plank  26 . As shown, the edges  18   a  and  18   b  are maintained in base plate grooves that are inward of the grooves that maintained the edges initially and the expander apex and take-up fastener head are raised from the base plate and upper level plank.  FIG. 3  is an enlarged view of the  FIG. 2  condition from a different view, showing the tension spring  20 , teeth  16  and intermediate grooves in greater detail. 
         [0031]      FIG. 4  shows an embodiment of the shrinkage compensation device  10  with the hinged expander  14  in the collapsed position just after installation. The spring  20  attached to the opposite leafs  14   a  and  14   b  is stretched and under tension and the outer edges  18   a  and  18   b  of the leafs  14   a  and  14   b  are locked by outer teeth  16 . 
         [0032]      FIG. 5  shows the shrinkage compensation device  10  after shrinkage of building materials with the expander  14  in an upwardly expanded position and greater clearance between the fastener head  28  and upper level plank  26 . The spring  20  has contracted relative to its position in  FIG. 4 , thereby drawing the leafs  14   a  and  14   b  inward and pushing the apex of the hinged expander  14  upward and raising the take-up fastener  24  relative to the top level  26  to compensate for the natural shrinkage of the building material. The outer edges  18   a  and  18   b  of the respective leafs  14   a  and  14   b  are locked by teeth positioned inward of teeth locking the edges in the collapsed position ( FIG. 4 ). 
         [0033]      FIG. 6  is a top view of the compensation device  10  in the expanded configuration shown in  FIG. 5 .  FIG. 7  shows an isometric view of the compensation device  10  in the expanded configuration shown in  FIG. 5 . 
         [0034]      FIG. 8  shows a representative building structure with the compensation device  10  in the raised/expanded position (like in  FIGS. 2 and 5 ). When initially installed, the take-up fastener  24  is driven through the passage defined by the holes in the apex of the hinged expander  14  and the base plate  12  through the upper level board  26  and into the lower level  27  (representative elements may not be drawn to scale). 
         [0035]    Preferred embodiments of the base plate  12  are made from galvanized steel of around 10-gauge thickness having a length between approximately 1.5 and 5 inches. Larger devices for use with rod securement can be up to 12 inches long. Preferred embodiments of the hinged expander  14  are made from galvanized steel of approximately 14-20 gauge thickness. 
         [0036]    In a typical building structure, shrinkage compensation devices  10  are secured to respective upper level frames in the manner described above approximately 6-60 inches apart. In some areas of building structures, like near a corner post, it may be desirable to secure two compensation devices right next to each other, for example, at approximately 2 inches apart off-center. Of course, all of the preferred materials, dimensions and installation characteristics disclosed herein are non-limiting to the inventive concept. 
         [0037]    With reference to  FIG. 9 , another embodiment of a hinged building shrinkage device  100  is disclosed. In most respects, the device  100  includes the similar elements and relationships, and operates in a similar way as compared to the prior embodiment of the device  10 . The device  100  includes an elongate base member  112  with a series of spaced teeth  116  on each of the opposite lateral ends. A hinged expander  114  with cooperative leafs  114   a  and  114   b  is mounted on the base member  112  with outer edges  118   a  and  118   b  of the leafs configured to engage with a notch between adjacent teeth  116 . An expanded compression spring  120  is attached to opposite leafs  114   a  and  114   b  biasing them toward one another. An opening  122  is defined in the apex portion of the hinged expander  114  between the respective leafs. 
         [0038]    In this embodiment, a takeup fastener  124  has a threaded outer surface  130  at least proximate an upper end. An inner nut  128  is fastened to the hinge leafs  114   a  and  114   b  via a pair of cross bolts  132 , and defines a threaded bore to engage with the threads  130  in the takeup fastener  124 . The hinged expander  114  is brought to its expanded position via rotation around the threads  130  of the takeup fastener in the direction to draw the apex of the expander  114  downward until the device is tightened with outer edges  118   a  and  118   b  of the leafs  114   a  and  114   b  within a notch of the base member  112 . Once the device  100  is tightened in a collapsed position, it operates just like the embodiment of the device  10 . As building materials shrink, the inward bias on the opposite leafs  114   a  and  114   b  via the spring  120  biases the apex portion of the expander  114  upward. Instead of biasing the takeup fastener upward via abutting with a head (like the head  28  of the previous embodiment), the take-up fastener  124  is continuously biased upward via the threaded engagement between inner nut  128  and threads  130 . 
         [0039]    While a preferred embodiment has been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit of the invention and scope of the claimed coverage.