Abstract:
A connector to connect a pair of components of a building and transfer a load from one to the other. The connector comprising a pair of members, each to be connected to a respective one of the components, and an adjustable abutment acting between the members to inhibit relative movement between the members in one direction. The ratchet mechanism acting between the members to permit movement in the one direction and to inhibit relative movement in an opposite direction, whereby adjustment of the abutment to cause relative movements in the one direction is accommodated by the ratchet mechanism.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Patent Application No. 61/193,375 filed Nov. 21, 2008, the contents of which are being incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a connector for use in building construction to permit relative movement between two components. 
     SUMMARY OF THE INVENTION 
     It is well known to use connectors to join components used in a building. These connectors may be as simple as plates extending across the joint between a pair of components or may be more complex so as to permit alignment and adjustment between the components. One area in which connectors are used is in the connection between a post and beam. Typically, such a connector will consist of a plate secured to the beam with a threaded rod extending from the plate into a bore in the end of the post. A nut on the threaded rod bears against the end face of the post and rotation of the nut can adjust the relative spacing between the end of the post and the beam. This is particularly useful to ensure that the post is properly supporting the beam in a horizontal manner and also to allow subsequent adjustment to accommodate building movement. 
     Movement of the building arises typically through the shrinkage of the wood used in the construction. Relatively small changes in the dimensional lumber can accumulate to represent a relatively large change in overall dimensions and, if this is not accommodated, the beam may not be properly supported or may not remain horizontal. This is particularly acute in log home construction using logs as the basic wall material as the logs are machined and assembled in a green state. Subsequent drying of the logs produces a significant change in the overall vertical height of the wall. 
     Many buildings also incorporate a porch or similar overhanging structure in which the roof structure projects beyond the walls and has its outer ends supported on a post. The roof structure is designed on the assumption that there are multiple points of support, that is the walls and the posts, and to maintain the integrity of the roof, it is therefore necessary to ensure that the top of the post and the walls remain aligned. Shrinkage of the wall, particularly where a log wall is used, can therefore impose significant bending loads on the roof that, in extreme cases, may result in failure of the roof. 
     Normally, the connection between the post and the roof structure is provided by a connector of the type described above so that the spacing between the end of the post and the roof can be adjusted as the building dries. This arrangement is satisfactory for normal static loads but does not take into account dynamic loads that may be imposed on the roof, such as by wind loads. In extreme weather conditions, the loads imposed on the roof, particularly on an overhanging roof, can create a net uplift on the roof structure. In this condition, the connection between the post and beam cannot provide any assistance to resist the uplift. The entire load is placed on the connection between the walls and the roof structure and failure of this connection can result in damage to the roof or loss of the roof in extreme circumstances. 
     Attempts have been made to provide a connector that will resist vertical loads in both directions while still accommodating limited vertical adjustment. One such device is that sold by Simpson Strongtie under model identification PPRC in which the threaded rod is received in a flange that is itself secured to a plate. The flange however has to be manufactured so as to allow rotation relative to the post to accommodate height adjustment but at the same time be retained by the plate. As such, there is significant overlap between the flange and the plate so that a very high torque is required when adjustments are to be made. These devices are suitable for relatively light loads only. 
     It is therefore an object to the present invention to provide a connector that permits adjustment between a pair of components whilst providing resistance to loads in opposite directions. 
     In general terms, the present invention provides a connector having a pair of members, one of which is to be secured to one component and the other of which is to be secured to the other component. An adjustable abutment acts between the two members to inhibit movement in one direction. A ratchet mechanism is also positioned between the two members that allows rotation in the one direction but inhibits it in the opposition direction. 
     Preferably, the ratchet mechanism includes a collet that engages the outer surface of a threaded rod and forms one of the members. The collet abuts an inclined face so that relative movement of the threaded rod in one direction causes the collet to engage the threaded rod and inhibit such movement. Preferably, also, the adjustment is a nut on the threaded rod that controls the relative disposition between the two members. 
     The connector may be used to connect a post and a beam structure and may be used at either end of the post. The post may be located within the building, such as to secure an upper floor or may be located outside the building, such as to support an overhanging porch. 
     Preferably the collet is spring biased into engagement with the threaded rod. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will now be described by way of example only with references to the accompanying drawings in which 
         FIG. 1  is schematic representation of a building. 
         FIG. 2  is a enlarged view of a portion of the building shown in  FIG. 1 . 
         FIG. 3  is an enlarged view of  FIG. 2 . 
         FIG. 4  is a view similar to  FIG. 2  of an alternative configuration. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring therefore to  FIG. 1 , a building, generally indicated  10 , has walls  12  constructed from logs  14  that support a roof structure  16 . The roof structure  16  has trusses  18  that include a lower chord  20  supported on a top plate  22  interposed between the uppermost log  14  and the chord  20 . 
     The chord  20  extends beyond the wall  12  to provide a roof structure for a porch and is supported by posts  24 . The posts  24  extend from a foundation  26  to a beam  28  that extends the length of the roof  16 . It will be appreciated that the number of posts will generally be less than the number of trusses  18  and that the beam  28  therefore spans several trusses  18  between the posts  24 . 
     A connector  30  is located on each of the posts  24 , either at the upper end adjacent to the beam  28 , as shown at post  24   a  in  FIG. 1 , or alternatively at the lower end of the post, as shown at post  24   b , in  FIG. 1 . Each connector is similar and simply inverted according to its disposition. For ease of reference, the connector  30  associated with the post  24   a  will initially be described with reference to  FIGS. 2 and 3 . 
     Referring therefore to  FIGS. 2 and 3 , the connector  30  includes a first member  31  with a plate  32  having holes  34  to receive fasteners  36 . Typically, the plate  32  is square and a hole  34  is located adjacent to each corner. A threaded rod  38  is welded to the plate  32  to project to one side of the plate. The threaded rod  38  can be either a fine or a coarse threaded rod and carries a nut  40  that acts as an adjustable abutment. A washer  42  has a central hole  44  through which the rod  38  can pass freely. The position of the washer  42  on the rod  38  is therefore controlled by the nut  40  which can be rotated on the threaded rod  38  to adjust the axial position of the nut  40  relative to the plate  32 . 
     The rod  38  is received in a central bore  46  of a barrel  48  that forms a secured member  49 . The barrel  48  has an external thread  50  at one end which is received in a threaded counter bore  52  of an end plate  54 . The end plate  54  has a central hole  56  through which the rod  38  can pass freely and has holes  58  to receive fasteners  60 . 
     The barrel  48  is counterbored to provide a internal chamber  62  continuing from the bore  56  and receiving the threaded rod  38 . End wall  64  of the chamber  62  is conical to provide end surfaces of the chamber  62  that are inclined to the axis of the bore  46 . 
     A ratchet mechanism located in the chamber  62  and includes a collet  66  with a pair of jaws  68  having inner part cylindrical faces  70  that are complimentary to the outer surface of the rod  38 . The jaws  68  each have inclined leading edges  72  at one end that are complimentary to the inclined face  64  of the chamber  62 . The opposite end of the jaws  68  is a radial face  74  to bear against a retainer washer  76 . The washer  76  is freely slidable on the threaded rod  38  and is biased into engagement with the jaws  68  by a spring  78 . The spring  78  acts between the retainer washer  76  and the plate  54  and is retained captive within the chamber  62 . 
     To install the connector  30 , a bore  80  is drilled in the end face  82  of the post  24   a . The bore  80  provides a clearance for the threaded rod  38  and extends a sufficient distance into the post  24   a  to accommodate the rod  38  over the extent of travel anticipated. The connector  30  is assembled so that barrel  48  is threaded on to the end plate  54  with the collet  66 , spring  78  and retainer washer  76  assembled within the chamber  62  and the end plate  54  then secured to the end face  82  of the post  24   a  with the fasteners  60 . The rod  38  may then be inserted into the central bore  46  with the rod  38  engaging the jaws  68  to move them away from the inclined surface  64  and increase that spacing to allow the threaded rod  38  to pass between the jaws  66 . The movement is accommodated by the spring  78 . With the rod  38  inserted, the post  24   a  may be positioned relative to the beam  28 . 
     Once the post  24   a  is positioned vertically, the nominal length of the connector  30  can be adjusted by rotating the rod  38  so that it is threaded out of the jaws  68 . Preferably the inner surfaces  70  are formed with a complimentary thread so that rotation of the rod  38  will cause axial adjustment relative to the barrel. During this assembly, the nut  40  is positioned adjacent to the plate  32  so as not to interfere with installation of the post  24   a  in the desired position. 
     With the plate  32  secured against the beam  28 , the fasteners  36  are inserted and the nut  40  threaded down the rod  38  to bring the washer  42  into abutment with the barrel  48 . In this position, the post  24   a  securely supports the beam  28  and relative vertical movement of the beam  28  toward the post  24   a  is inhibited by the nut  40  on the rod  38 . At the same time, the jaws  68  are thus held in engagement with the inclined surface  64  so that the jaws  68  engage the surface of the rod  38  by virtue of the spring  78 . The opposite end of the post  24   a  is secured to the foundation  26  by a conventional fixed fastener to prevent vertical movement. 
     In the event that an upward vertical load is applied to the beam, for example due to wind loading, the rod  38  will attempt to move vertically out of the barrel  48 . The jaws  68  are carried with the rod  38  and by virtue of the inclined surfaces  64  are forced into engagement with the rod  38  to inhibit any relative movement between the rod  38  and the barrel  48 . A secure connection between the beam  28  and the post  24   a  is thus provided. 
     When it is necessary to reduce the relative vertical spacing between the beam  28  and the post  24   a  due to shrinkage of the walls  12 , the nut  40  is rotated to move it along the threaded rod  38  toward the beam  28 . The rotation permits the rod  38  to move relative to the barrel  48  into the bore  80  and carries the jaws  68  away from the inclined surface  64 . The jaws  68  spread within the chamber  62  allowing the threaded rod  38  to pass between the jaws  68  in an axial direction. The nut  40  therefore governs the relative spacing between the beam  28  and the post  24   a  and may be used to ensure that the lower chord  20  of the truss  18  is properly supported on the wall  14  and the post  24 . Any upward vertical movement caused by reversed loading of the roof will again cause the jaws  68  to engage the rod  38  and inhibit such movement. 
     It will be seen therefore that by providing the ratchet connection between the rod  38  and the post  24  by the spring loaded collet, so that relative movement is permitted in one direction but inhibited in the opposite, vertical adjustment between the beam and the post can readily be accommodated but at the same time, relative movement in the opposite direction is inhibited. 
     As indicated in  FIGS. 1 and 4 , the connector  30  may similarly be used at the opposite end of the post such that the plate  54  is secured to the lower end face of the post  24   b  and the opposite end face of the post  24   b  connected directly to the beam  28 . In this arrangement, the plate  32  is secured to the foundation  26  and adjustment between the post  24   b  and the beam  28  accomplished as described above. Again, the connector  30  is effective to resist reverse loading on the roof whilst permitting proper adjustment to maintain alignment between the beam  28  and the walls  14 . 
     The connector  30  has been described above in the context of securing an external over hanging roof structure. It will of course be apparent that similar connections can be used within the structure of a building to connect a supporting beam to a foundation or other structure and accommodate vertical loading. The connector  30  is able to resist the reversed loadings induced by high winds passing over the roof while still maintaining the functionality to permit adjustment of the relative alignment between the different building components. The connector may therefore be used in a basement to support a beam in the main floor of the building, or could be used in an upper floor within a wall structure to connect a roof structure to an internal support beam.