Abstract:
A system for forming a movable slab foundation comprises a support sleeve encased within a slab foundation. The support sleeve surrounds a support member that rests upon a support surface. The support sleeve is capable of moving axially along the length of the support member.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to provisional application 61/031,904, filed Feb. 27, 2008. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates in general to forming an adjustable foundation, and in particular, to a concrete slab foundation capable of being raised above the ground. 
       BACKGROUND OF THE INVENTION 
       [0003]    Many structures have been built on foundations or slabs made of concrete poured on top of soil. Constant changes in the weather and moisture levels in the soil frequently cause damage to such a foundation. In many instances, the foundation may buckle or even crack. This phenomenon occurs for a variety of reasons, including uneven changes in the water content of supporting soils, uneven compacting of soils, and uneven loads being placed on soils. Over time, uneven movement in the soils under a foundation can cause a foundation to bend or crack. 
         [0004]    Therefore, it would be desirable to provide a method and apparatus that would allow a foundation to be poured on top of soil and subsequently raised to a desired height to eliminate potential problems caused by soil movement and/or problematic soils. 
       SUMMARY OF THE INVENTION 
       [0005]    A support surface is comprised of a concrete pier with a base plate encased therein. The base plate has anchor bolts extending therefrom and into the concrete pier a selected distance. A vertical support member has a substantially cylindrical hollow body with first and second ends. The first end of the support member body is in abutting contact with the base plate. 
         [0006]    A support sleeve has a hollow body with inner and outer surfaces. The support sleeve surrounds the support member. The inner surface of the support sleeve body has threads contained therein. The outer surface of the support sleeve body has reinforcing bars connected to and extending outwardly therefrom. A plurality of nuts are also connected to and extend outwardly from the outer surface of the support sleeve body. A plurality of eye bolts are connected to the plurality of nuts and extend upwardly therefrom. 
         [0007]    The support sleeve and the reinforcing bars extending therefrom are encased within a slab foundation. The support sleeve and the slab foundation are capable of moving axially along the length of the support member. 
         [0008]    A lifting member has a body with first and second ends and is positioned such that it is surrounded by the support member. The first end of the lifting member body is in abutting contacting with the base plate. The lifting member has a length greater than the desired final height of the slab foundation. 
         [0009]    A locking nut has a hollow body with inner and outer surfaces and is positioned in abutting contact with the second end of the support member. The outer surface of the locking nut has threads therein adapted to engage the threads on the inner surface of the support sleeve. 
         [0010]    A lifting device is coupled to the second end of the body of the lifting member to move the support sleeve and the slab foundation axially along the length of the support member to a desired height. A plurality of attachment members are connected to and extend between the plurality of eye bolts and the lifting device. The lifting device is activated causing the attachment rods to move simultaneously, thereby causing the support sleeve and the slab foundation to move axially along the length of the support member. The support sleeve and the slabe foundation are lifted above the ground to a desired height. 
         [0011]    Once the slab foundation and support sleeve have reached a desired height, the locking nut will be in contact with the top of the support sleeve. In order to secure the slab foundation and the support sleeve at the desired height, the locking nut is screwed into the threads on the inner surface of the support sleeve. The support sleeve, slab foundation, and locking nut rest upon the second end of the support member body. Once the locking nut is securely connected to the support sleeve, the attachment rods, hydraulic jack, and lifting rod may be removed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a sectional view of the pier supported slab foundation raised above ground level. 
           [0013]      FIG. 2  is a sectional view of a single slab support, illustrating the concrete pier, base plate, and support member. 
           [0014]      FIG. 3  is a side view of the support sleeve fixture, shown prior to its placement around the support member. 
           [0015]      FIG. 4  is top view of  FIG. 3   
           [0016]      FIG. 5  is a bottom view of  FIG. 3 . 
           [0017]      FIG. 6  is an isometric view of the pier and support member, with the support sleeve placed around the support member. 
           [0018]      FIG. 7  is an isometric view of  FIG. 6 , with the concrete slab poured, the lifting member inserted with the lifting device mounted atop, and the locking nut placed around the lifting member. 
           [0019]      FIG. 8  is a side view of  FIG. 7  with the concrete slab and support sleeve assembly raised above ground level. 
           [0020]      FIG. 9  is a side view of the pier and support member, with the slab and sleeve locked in place with the locking nut, and the lifting device and lifting member removed. 
           [0021]      FIG. 10  is a side view of  FIG. 9 , with the eye bolts removed, and the slab locked into place with the locking nut. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    Referring to  FIG. 1 , foundation slab  11  may be used to support a house or other building. In this embodiment, slab  11  is of concrete and is supported above the ground a few feet by support surfaces or piers  13 . Piers  13  are of concrete and have base plates  15  embedded within them. Base plates  15  have anchor bolts  17  that extend a selected distance into concrete piers  13 . 
         [0023]    Referring to  FIG. 2 , the holes for piers  13  are dug with a diameter such that base plates  15  are fully encased within the concrete. Once the holes are dug, piers  13  are formed by pouring concrete into the holes. The base plates  15  are then embedded in the concrete of piers  13  such that the top of base plate  15  is flush with surface of the concrete. Anchor bolts  17  are connected to base plates  15  and extend into the concrete a distance below base plate  15 . A plurality of supporting members or supporting pipes  19  are positioned such that a first end portion of each supporting pipe  19  rests on a corresponding base plate  15 . Supporting pipes  19  extend upwardly a selected distance from each base plate  15 . The length of supporting pipes  19  can be varied to accommodate various desired slab  11  heights. 
         [0024]    Referring to  FIG. 3 , a support sleeve  21  with a greater diameter than supporting pipe  19 , and cut with a length equal to the desired thickness of the concrete slab  11  is constructed so that it may slide over supporting pipe  19 . The inner surface  23  of sleeve  21  has threads  25  formed therein and extending along a length of sleeve  21 . Reinforcing bars (rebar)  27  are connected to the outer surface of sleeve  21 . In this embodiment, a first portion  29  of rebar  27  is welded to sleeve  21  vertically along the length of sleeve  21 . A second portion  31  of rebar  27  is connected to and extends outwardly and downwardly at an angle from first portion  29  of rebar  27 . A third portion  33  of rebar  27  is substantially perpendicular to support sleeve  21  and extends between first portion  29  and second portion  31  of rebar  27 . Rebar  27  is welded around the outer peripheries of sleeve  21  at 60 degree intervals. Two nuts  35 , offset from rebar  27 , are welded to opposite sides of an end portion of sleeve  21 . A pair of eye bolts  37  are screwed into nuts  35 . The lengths of eye bolts  37  can be varied depending upon the desired thickness of slab  11 , but will always be of a length such that they protrude upwardly from slab  11 . 
         [0025]    Referring to  FIGS. 4 and 5 , rebar  27  are welded and extend from the sleeve  21  at positions that create an asterisk-like pattern. Nuts  35  are positioned parallel with one another and offset from rebar  27  and are welded in place on opposite sides of sleeve  21  Eye bolts  37  are aligned with and screwed into nuts  35 . 
         [0026]    Referring to  FIG. 6 , the sleeve assembly ( FIG. 3 ) is then slid down supporting pipe  19 , and lowered to the desired height for pouring slab  11 . Concrete slab  11  is then poured, which embeds rebar  27  and the sleeve assembly ( FIG. 3 ) within slab  11 . The concrete is kept from bonding to concrete pier  13 , base plate  15 , and eye bolts  37  by a bond breaker layer (not shown). The tops of eye bolts  37  are left protruding from the top of concrete slab  11 . 
         [0027]    Referring to  FIG. 7 , after the cement and slab  11  have hardened, a lifting member or solid lifting rod  39 , with a smaller diameter than supporting pipe  19 , is inserted into supporting pipe  19  and lowered until it makes contact with base plate  15 . The length of lifting rod  39  is greater than the desired final height of slab  11 . After lifting rod  39  is in place, a locking nut  41  with a diameter greater than lifting rod  39  but equal to supporting pipe  19  is placed around the support rod  39 . Locking nut  41  has threads on its outer surface to mate with threads  25  ( FIG. 3 ) on inner surface  23  of sleeve  21 . Locking nut  41  is slid down support rod  27 , until it comes into abutting contact with the top of support pipe  19 , which corresponds to the desired height of slab  11 . A lifting device is then mounted on the top of each support rod  39 . In this embodiment, the lifting device is a hydraulic jack  43  mounted on the top of each support rod  39 . Attachment members or attachment rods  45  are then attached to eye bolts  37 , in order to lift slab  11  to its desired height. Hydraulic jack  43  is then connected to attachment rods  45 . Referring to  FIG. 8 , hydraulic fluid pressure is then applied simultaneously to all of the jacks  43 , causing foundation slab  11  to be lifted above the ground to the desired height. 
         [0028]    Referring to  FIG. 9 , once slab  11  has reached its desired height, locking nut  41  will be in contact with the top of sleeve  21 . In order to secure slab  11  at the desired height, locking nut  41  is screwed into the threads  25  ( FIG. 3 ) on the inner surface  23  of sleeve  21 . The support sleeve  21 , slab foundation  11 , and locking nut  41  rest upon the second end portion of the support member  19 . Once locking nut  41  is securely connected to sleeve  21 , attachment rods  45 , hydraulic jack  43 , and lifting rod  39  are removed. 
         [0029]    Referring to  FIG. 10 , after removing hydraulic jack  43 , eye bolts  37  are unscrewed from nuts  35  and removed from the slab  11 , leaving holes  47  on the top surface of slab  11 . In the event that the height of slab  11  needs to be adjusted, eye bolts  37  may reinserted into slab  11  and screwed into nuts  35  which are welded to concrete encased sleeve  21 . At that point, lifting rod  39  would be reinserted, and hydraulic jack  43  and attachment rods  45  would be reconnected. The locking nut  41  would then be unscrewed from sleeve  21 , and slab  11  could be raised and lowered to a desired height using hydraulic jack  43 . In the event that slab  11  needs to be raised to a height greater than the current supporting pipe  19  allows, slab  11  can be lowered to its original position and supporting pipe  19  may be replaced with a supporting pipe with a length to accommodate the new desired height. Once the desired height has been reached, as previously illustrated, slab  11  may be secured in place with locking nut  41 , and hydraulic jack  43 , attachment rods  45 , lifting rod  39 , and eye bolts  37  may be removed.