Abstract:
An anchor particularly adapted to be embedded into a concrete construction for suspension of a ceiling panel, duct or the like, includes a base which receives inserts that have an axial threaded bore. The base is open at its lower end and can receive a threaded rod by virtue of ratcheting inserts received within the base. The inserts and base are particularly shaped to prevent jam and ease of insertion of the rod in the anchor. The anchor also has a head flange that sits above a plurality of fasteners secured to the anchor which is used to simultaneously drive the fasteners into a form for the concrete member. The fasteners are connected to the anchor extending in generally parallel and spaced relation to the anchor. The fasteners can be held by a support or sleeve-like holder which surrounds at least a portion of the base of the anchor or they can be attached to the base of the anchor. The fasteners project downwardly through the bottom of the anchor for driving into the form board.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates to an anchoring device, and more particularly, to a concrete anchor which is embedded in a concrete ceiling for suspension of a ceiling panel, electrical wiring pipe, air conditioning device, or the like. 
         [0002]    Concrete anchors are well known in the prior art. They provide a means to hang building systems from concrete ceilings. The anchors are installed prior to pouring the concrete into a form that creates the level of a building. The concrete anchors are located in the ceiling at the proper locations by attaching them to the form that supports the concrete as it is hardening. The best concrete anchors are inexpensive to make and assemble, are quickly placed in the proper position on the form, are resistant to cement entering into the working mechanisms of the anchor, and can accept a variety of sizes of threaded rods for supporting the building elements. U.S. Pat. No. 1,940,545, issued in 1933 to Holmes, teaches an early concrete anchor made from cast iron and is hereby incorporated by reference. U.S. Pat. No. 3,405,497, issued in 1968 to McNair, teaches a modern concrete anchor made from both metal and plastic components to reduce the cost of manufacture and is hereby incorporated by reference. The use of plastic components also facilitates identification of the anchors by using differing colors of plastic which can be used to instruct users about the size of rod that can be used with the anchor. U.S. Pat. No. 4,211,048, issued in 1980 to Naka, also teaches a concrete anchor made from both metal and plastic components and is hereby incorporated by reference. The Naka patent focused on improving the manner in which the anchor is connected to the form. Naka shaped the parts, particularly the top of the anchor, so that the nails that attach the anchor to the form can be driven simultaneously. Published Japanese Patent Application 5-230893, filed in 1982, teaches a concrete anchor where the anchor receiving portion is made with a plurality of internal diameters so that one anchor can receive different sized threaded rods. U.S. Pat. No. 6,240,697, issued in 2001 to Thompson et al, also teaches a concrete anchor made from both metal and plastic components that can receive threaded rods of multiple diameters, the contents of which are hereby incorporated by reference. 
         [0003]    A problem with all of the concrete anchors taught by the prior art is that the rod needs to be threaded into the anchor. This slows down installation of the suspended system and can be difficult as the user is generally working from below. There are a number of systems in the prior art where a threaded member is received by a slip nut or other device to hold the threaded member in place without having to thread the rod into the slip nut. U.S. patent application Ser. No. 13/531,159, filed Jun. 22, 2012, teaches an automatic take-up device that has threaded inserts that can receive a threaded rod without having to rotate the threaded rod into the device, the contents of which are hereby incorporated by reference. 
         [0004]    The present invention provides a concrete anchor with inserts that can receive a threaded rod without having to thread the rod into the device that can be used with confidence in a concrete anchor where the anchor will be encapsulated by concrete and otherwise inaccessible to the user except for inserting the rod into place. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention provides an anchor device for connecting a rod to a first structural member, in particular for suspending rods from a concrete ceiling, where the anchor device is encapsulated in concrete except for its bottom which is exposed, and yet can reliably grasp and hold a threaded rod without having to thread the rod into the member. This object is achieved by using ratcheting inserts received within the anchor. 
         [0006]    It is an object of the present invention to provide a concrete anchor which allows for the insertion of rods of different sizes without requiring the rods be threaded into the concrete anchor. This object is achieved by forming the inserts with a rod receiving bore having multiple internal diameters. 
         [0007]    It is another object of the present invention to provide a concrete anchor which is simple in construction and easy to manufacture, and yet can receive a sufficient length of a threaded rod without jamming so as to reliably hold the threaded rod. 
         [0008]    It is also an object of the present invention to provide a concrete anchor that is easily installed in the form for the concrete member. This object is achieved by forming the insert receiving bore of the anchor with a bottom ledge and lip. This object is also achieved by forming the insert receiving bore with a smaller diameter mid-section. This object is also achieved by forming the inserts with frusto-spherical surfaces that engate the lower portion of the insert receiving bore. The object is also achieved by forming the inserts with external tabs that interface with notches in the housing and forming the tabs partially with sloping surfaces where they interface with the notches. 
         [0009]    In accordance with the present, there is provided an anchor adapted to be embedded into a concrete construction for suspension of a ceiling panel, duct or the like. The anchor includes a base which receives inserts that have an axial threaded bore. The base is open at its lower end. The anchor also preferably has a head flange that sits above a plurality of fasteners secured to the anchor which is used to simultaneously drive the fasteners into a form for the concrete member. The fasteners are connected to the anchor extending in generally parallel and spaced relation to the anchor. The fasteners can be held by a support or sleeve-like holder which surrounds at least a portion of the base of the anchor or they can be attached to the base of the anchor. The fasteners project downwardly through the bottom of the anchor for driving into the form board. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective view of a first embodiment of the present invention. 
           [0011]      FIG. 2  is an exploded, perspective view of the first, preferred embodiment of the present invention. 
           [0012]      FIG. 3  is a top view of the base of the first, preferred embodiment of the present invention. 
           [0013]      FIG. 4  is a sectional side view of the base of the first, preferred embodiment of the present invention. 
           [0014]      FIG. 5  is a top view of the cap of the first, preferred embodiment of the present invention. 
           [0015]      FIG. 6  is a sectional, side view of the cap of the first, preferred embodiment of the present invention. 
           [0016]      FIG. 7  is a top view of the compression spring of the first, preferred embodiment of the present invention. 
           [0017]      FIG. 8  is a sectional, side view of the compression spring of the first, preferred embodiment of the present invention. 
           [0018]      FIG. 9  is a top view of the inserts of the first, preferred embodiment of the present invention. 
           [0019]      FIG. 10  is a side view of a pair of the inserts of the first, preferred embodiment of the present invention. 
           [0020]      FIG. 11  is a top view of the inserts inserted into the base of the first, preferred embodiment of the present invention. 
           [0021]      FIG. 12  is an exploded sectional, side view of the first, preferred embodiment of the present invention. 
           [0022]      FIG. 13  is sectional, side view of the first, preferred embodiment of the present invention attached to a wood form. 
           [0023]      FIG. 14  is a sectional, side view of the first, preferred embodiment of the present invention installed in a concrete form with the form board removed and a threaded rod inserted into the concrete anchor. 
           [0024]      FIG. 15  is a sectional, side view of the first, preferred embodiment of the present invention installed in a concrete form with the form board removed and a threaded rod of differing diameter than the threaded rod shown in  FIG. 14  inserted into the concrete anchor. 
           [0025]      FIG. 16  is a perspective view of a second preferred embodiment of the present invention. 
           [0026]      FIG. 17  is an exploded, perspective view of the second, preferred embodiment of the present invention. 
           [0027]      FIG. 18  is a top view of the holder of the second, preferred embodiment of the present invention. 
           [0028]      FIG. 19  is a sectional side view of the holder of the second, preferred embodiment of the present invention. 
           [0029]      FIG. 20  is a top view of a washer of the second, preferred embodiment of the present invention. 
           [0030]      FIG. 21  is a sectional, side view of the washer of the second, preferred embodiment of the present invention. 
           [0031]      FIG. 22  is a top view of the compression spring of a first, preferred embodiment of the present invention. 
           [0032]      FIG. 23  is a sectional, side view of the compression spring of a first, preferred embodiment of the present invention. 
           [0033]      FIG. 24  is a top view of the plate used with the cap of the second, preferred embodiment of the present invention. 
           [0034]      FIG. 25  is a sectional side view of the plate used with the cap of the second, preferred embodiment of the present invention. 
           [0035]      FIG. 26  is a top view of the cap of the second, preferred embodiment of the present invention. 
           [0036]      FIG. 27  is a sectional, side view of the cap of the second, preferred embodiment of the present invention. 
           [0037]      FIG. 28  is a top view of the inserts of the second, preferred embodiment of the present invention. 
           [0038]      FIG. 29  is an exploded, top view of the inserts of the second, preferred embodiment of the present invention. 
           [0039]      FIG. 30  is a sectional, side view of the inserts of the second, preferred embodiment of the present invention. 
           [0040]      FIG. 31  is a top view of the inserts inserted into the base of the second, preferred embodiment of the present invention. 
           [0041]      FIG. 32  is a partial, exploded sectional, side view of the second, preferred embodiment of the present invention. 
           [0042]      FIG. 33  is sectional, side view of the second, preferred embodiment of the present invention attached to a wood form. 
           [0043]      FIG. 34  is a sectional, side view of the second, preferred embodiment of the present invention installed in a concrete form with the form board removed and a threaded rod inserted into the concrete anchor. 
           [0044]      FIG. 35  is a sectional, side view of the second, preferred embodiment of the present invention installed in a concrete form with the form board removed and a threaded rod of differing diameter than the threaded rod shown in  FIG. 34  inserted into the concrete anchor. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0045]    The present invention teaches a concrete anchor or anchor  1  that is attached to a form  2  with nails  3  and can receive a threaded rod or tie rod or threaded bolt or vertical bolt  4 .  FIG. 1  shows a first, preferred embodiment of the concrete anchor  1  of the present invention.  FIG. 13  shows the anchor  1  connected to form  2 .  FIG. 14  shows the anchor  1  embedded in a concrete member that can be considered a first structural member. 
         [0046]    For clarity and convenience, the concrete anchor  1  of the present invention is described in a single, most common, orientation (except as noted otherwise) in which a top  5  faces up and a bottom  6  faces down. The concrete anchor  1  can, nevertheless, be installed in essentially any orientation, so that the top  5  can face down or to the side and the bottom  6  can face up or to the side so long as there is sufficient tension generated between the threaded rod  4  and the concrete anchor  1  for the anchor to grasp the threaded rod  4 . 
         [0047]    As shown in  FIGS. 12 and 15 , the concrete anchor  1  of the present invention is provided with inserts  7  with concavities forming an interior rod receiving bore  8 . The interior receiving bore  8  receives the threaded rod  4 . The use of inserts  7  allows the threaded rod  4  to be inserted into the concrete anchor  1  without threading or rotating the threaded rod  4  into the anchor  1 . 
         [0048]    The inserts  7  are formed and arranged so that they can grasp and hold a tie rod  4  received in the concrete anchor  1  that is typically subject to a tension load either from the weight of the tie rod  4  itself or from the weight of a member attached to the tie rod  4 . The concrete anchor  1  is also preferably formed with a compression member  9  and narrowing base or housing  10  that pushes the inserts  7  downwardly and around the threaded rod  4  to grasp the threaded rod  4 . The compression member  9  is shown by itself in  FIGS. 7 and 8 . The tie rod  4 , inserts  7  and the base  10  are formed such that when the tie rod  4  moves downwardly with respect to the housing or base  10 , the inserts  7  will be pulled downwardly in the base or housing  10  as well. As shown in  FIG. 4 , the tension on the tie rod  4  combined with the narrowing in the lower portion  17  of the insert receiving bore or base bore  11  of the housing  10  causes a constriction of the insets  7  about the tie rod  4  forcing them to grasp and hold the tie rod  4 . 
         [0049]    When a tie rod  4  is first inserted up into the base  10 , the upward movement of the tie rod  4  forces the inserts  7  apart from a constricted position. The constriction is preferably caused by the downward force of gravity, or tension on the rod  4 , and also preferably by a compression member  9  placed above the inserts  7 , combined with the narrowing in the lower portion  17  of the insert receiving bore  11  of the housing  10 . The interface between the surface of the tie rod  4  and the inserts or insert segments  7  creates a ratcheting action as the tie rod  4  is pushed up and the insert segments  7  move up and out laterally, allowing the tie rod  4  to be inserted as far as needed into the housing  10  for installation. 
         [0050]    Rather than being screwed into the inner bore or interior rod receiving bore  8 , the threaded rod  4  is preferably pushed in without rotation and the inserts  7  react by moving apart and together, ratcheting when the threaded inner rod receiving bore  8  interfaces with a threaded bolt  4 . The compression member  9  allows the inserts  7  to move up within the housing  10 , and the upwardly-widening base bore  11  allows the insert segments  7  to move apart. This allows the threaded bolt  4  to be inserted into the inner bore  8 , and as the threaded bolt  4  and the threaded portions  12  of the inner surface  13  of the inserts  7  slide against each other, the inserts  7  are moved up and outwardly and down and inwardly repeatedly, the inward motion urged by the compression member  9  and the narrowing base bore  11  in the housing  10 . The threaded bolt  4  can only be inserted in one direction because when it is pulled down, the downwardly-narrowing outer base bore  11  forces the insert segments  7  against the threaded rod  4  so that the threaded bolt  4  and the threaded portion  12  of inner surface  13  of the inserts  7  interlock as if the threaded bolt  4  had been screwed into a conventional solid nut. 
         [0051]    As shown in  FIGS. 2 and 10 , the interior receiving bore  8  of the inserts  7  is preferably made with a lower portion  14 , having a first selected diameter, an upper portion  15  having a second selected diameter, and a middle portion  16  or portions having differing selected diameters. This allows the concrete anchor to receive threaded rods  4  of differing, selected diameters. Preferably, the lower portion  14  receives the rod  4  with the largest diameter, and the upper portion  15  receives the rod  4  with the smallest diameter. 
         [0052]    The inserts  7  are received in the base or housing  10  that contains them by the insert receiving or base bore  11  of the base or housing. The base  10  is preferably a seamless, unitary member. The lower portion  17  of the base bore  11  narrows to cause the inserts  11  to constrict around the threaded rod  4 . 
         [0053]    The concrete anchor  1  of the present invention preferably has four inserts  7 . Greater or lesser numbers of inserts are possible, but four is preferred. 
         [0054]    As shown in  FIG. 14 , the inserts  7  are designed to grasp a preferably vertical tie rod or threaded bolt  4 . Preferably, vertical tie rod  4  has threads  18  and is at least threaded where it is grasped by insert segments. Vertical tie rod  4  can be wholly threaded, partially threaded, or unthreaded, although if its unthreaded it is preferable to have grooves  19  on its surface that can mate with similar grooves  20  (shown in  FIG. 12 ) on the inserts  7  for achieving design load values, although alternate methods of grasping the tie rod  4  by the inserts  7  is encompassed within the invention. The inserts  7  preferably surround the tie rod or threaded bolt  4 , but with gaps between the inserts  7 . 
         [0055]    As shown in  FIG. 9 , each insert  7  preferably has first and second substantially planar sides  21  and  22  which are preferably perpendicular to the top surface  23 . The first and second substantially planar sides  21  and  22  are preferably orthogonal to each other. 
         [0056]    As shown in  FIG. 2 , each insert  7  preferably has a rough, threaded, concave inner bore-defining surface  24  that extends downward from the top or near the top of the insert and connects the first and second substantially planar sides  21  and  22 . Preferably, each interior bore-defining surface  24  is primarily a section of a rough, threaded, right circular cylindrical surface that defines the inner bore  8 . 
         [0057]    As shown in  FIG. 9 , each insert  7  preferably has a base-bore interfacing surface or outer wall  25  that extends downward from the top surface  23 . The base-bore interfacing surfaces  25  preferably taper from the top surface  23  of the inserts to the bottom edge  26  of the insert  7 , reducing the cross-section of each insert from the top surface  23  to the bottom edge  26 . As shown in  FIG. 10 , preferably, the general shape of the upper portion  27  of the base-bore interfacing surface  25  of the inserts is collectively that of a cylinder. In one preferred embodiment of the invention shown in  FIGS. 16-35 , the inserts  7  are formed with tabs  28  splayed circumferentially on the base-bore interfacing surface  25 . As shown in  FIGS. 10 and 30 , the lower portion  29  of the base-bore interfacing surface  25  of the inserts  7  curves or slopes inwardly. 
         [0058]    The height of the inserts  7  and the lengths of the threaded portions  12  of the inserts  7  is sufficient to grasp enough of the tie rod or threaded bolt  4  for a secure connection by connecting to multiple turns of the thread or grooves  19  of the rod or bolt  4 . 
         [0059]    Preferably, the inserts  7  are retained within the base bore  11  by a compression member  9 . In one preferred embodiment, the compression member  9  preferably comprises a lower hard washer  30  and an upper soft washer  31 . The soft washer  31  is preferably made from a resilient material like rubber that, when compressed, stores energy and expands when compression forces are released. Preferably, the soft washer  31  is made from soft, quick-recovery, super-resilient polyurethane foam. The soft washer  31  functions like a standard metal compression spring and a spring could be used, but the foam washer is preferred. The lower washer  30  is preferably made from steel. 
         [0060]    As shown in  FIG. 13 , the concrete anchor  1  is preferably attached to the wooden form  2  by means of fasteners  3 , preferably nails  3  that are inserted through openings  32  in the concrete anchor  1  and driven into the form board  2 . The fasteners  3  are preferably angularly spaced around the concrete anchor  1 , and are driven by driving the head flange  33  of the concrete anchor  1  which translates the force to the fasteners  3  simultaneously. The fasteners  3  extend downwardly from the lower surface  34  of the head flange  33  in preferably parallel and spaced apart relationship. 
         [0061]    In the first preferred embodiment of the present invention, shown in  FIGS. 1-15 , the base or housing  10  is formed with openings  32  for grasping and holding the fasteners  3 , and the bottom  35  of the base or housing  10  is in contact with the top surface  36  of the form board  2  for the concrete member  37 . 
         [0062]    As shown in  FIG. 4 , in the first preferred embodiment, the base bore  11  of the housing  10  has a first sliding surface  38  disposed at an angle to the longitudinal axis  39  of the anchor that forms part of the lower portion  17  of the base bore or insert receiving bore  11 . This first sliding surface  38  is preferably frusto-conical in shape. 
         [0063]    Above the base first sliding surface  38  is an upper housing wall  40  with an angle of ascension much greater than the base first sliding surface  38 . This upper housing wall  40  is preferably vertical. 
         [0064]    In the first preferred embodiment shown in  FIGS. 1-15 , inwardly from the first sliding surface  38 , the base is formed with a bottom base-bore ledge  41 . Inwardly from bottom ledge  41  towards the axis  39  of the anchor  1 , a lip  42  is provided with an angled, ascending face  43  towards the longitudinal axis  39  of the anchor. The base-bore ledge  41  and lip  42  stabilize the inserts  7  in the housing which have interior tapering surfaces  44  that correspond to the angle of the lip  42 . 
         [0065]    In the first preferred embodiment shown in  FIGS. 1-15 , when the inserts  7  are vertical and sitting at the bottom or as far down in the base bore  11  of the housing as they can go, and in their constricted state, insert first sliding surfaces  45  located at the base of the inserts  7  mate with the housing first sliding surface  38 . In the first preferred embodiment, the insert first sliding surface  45  is shorter than the housing first sliding surface  38  (that is to say that they do not extend as far upwardly or away from the longitudinal axis of the anchor  39 ) and the inserts  7  can travel upwardly along the housing first sliding surface  38 . 
         [0066]    Above the insert first sliding surface  45 , the inserts  7  are formed with insert walls  25  with an angle of ascension much greater than the insert first sliding surface  45 . The upper insert walls  25  are preferably vertical. In the first preferred embodiment, when the inserts are vertical and sitting at the bottom of the housing, and in their constricted state, the upper insert walls  25  are located away from the housing upper walls  40 . 
         [0067]    In the first preferred embodiment, a compression member  9  is preferably located between the inserts  7  and a cap  46  which is attached to the top of the housing or base  10 . In the first preferred embodiment the cap  46  is threaded onto the housing  10 . The cap  46  is formed with the head flange  33  that extend over the heads  47  of the fasteners  3 . The fastener heads  47  are in contact with the bottom  48  of the cap to translate driving forces applied to the top  49  of the cap  46  to the fasteners  3 . The fasteners  3  are formed with pointed tips  50  for making it easier to drive the fasteners  3  into the form  2 . Aligned tabs  51  at the base and near the top of the housing  10  hold the fasteners  3  to the housing  10 . 
         [0068]    In the second preferred embodiment of the present invention, shown in  FIGS. 16-35 , the base or housing  10  is received by a holder  52 . As best shown in  FIG. 19 , the holder  52  is formed with openings  32  for grasping and holding the fasteners  3 , and the bottom  53  of the holder is in contact with the form board  2  for the concrete form  2 . The holder  52  separates the base  10  from the top surface  36  of the form board  2 . The holder  52  is formed with a base receiving bore  54  that has a base receiving ledge or shoulder  55  substantially above the bottom of the holder  53 . The bottom of the base  35  interfaces with the shoulder  55  in the base receiving bore  54 . The holder  52  can be made from plastic which is much cheaper to manufacture than the base  10  which needs to be sufficiently strong to resist the outward pressure generated by the inserts  7  when a tension load is applied to the threaded rod  4  received in the anchor  1 . With the use of the holder  52 , the base  10  can be made shorter and from less material, thus reducing its cost of manufacture. The base receiving bore  54  of the holder is shaped so that the base  10  when inserted into the holder  52  with the bottom of the base  35  touching the shoulder of the holder  55 , the base  35  protrudes slightly above and beyond the top of the holder  52 . The base receiving bore  54  of the holder  52  is shaped to create a close friction fit between the holder  52  and the base  10 . 
         [0069]    In the second preferred embodiment, the insert receiving bore or base bore  11  of the housing  10  has a first sliding surface  38  disposed at an angle to the longitudinal axis of the anchor  39 . This first sliding surface  38  is preferably frusto-conical in shape, but it could also be frusto-spherical. 
         [0070]    Above the base first sliding surface  38  is a middle housing wall  56  with an angle of ascension much greater than the base bore first sliding surface  38 . This middle housing wall  56  is preferably vertical. The middle housing wall  56  extends upwardly for only a short distance, until it reaches a shoulder  57  which has an angle of ascension that is less than the middle housing wall  56 . The shoulder  57  is preferably an annular ledge  58  that is orthogonal to the longitudinal, central axis  39  of the anchor  1 . Above the annular ledge  58  an upper housing wall  40  extends at an angle of ascension much greater than the first sliding surface  38  of the base  10 . This upper housing wall  40  is preferably vertical. The middle housing wall  56  is preferably cylindrical in shape and has a diameter large enough to contain the lower portions of the inserts  7  in their constricted position. 
         [0071]    In the second preferred embodiment, below the base first sliding surface  38 , the wall of the base-bore  11  descends at an angle of descent that is greater than the angle of base first sliding surface  38 . This angle is preferably vertical or aligned with the axis of the anchor, creating a lower housing wall  59 . 
         [0072]    In the second preferred embodiment, when the inserts  7  are vertical and sitting at the bottom of the housing  10 , and in their constricted state, insert first sliding surfaces  45  located at the base of the inserts  7  contact the base first sliding surface  38 . In the second preferred embodiment, the insert first sliding surface  45  can travel upwardly along the base first sliding surface  38 . In the second preferred embodiment, the insert first sliding surface  45  is frusto-spherical and in contact with the housing or base first sliding surface  38  which is frusto-conical. The lower portions of the inserts  7  collectively have the geometry of a spherical segment—a spherical cap with the top truncated, or a spherical frustum. The inserts  7  are inserted in the base bore  11  of the housing  10 . The lower sliding surfaces  45  of the insert segments  7  are able to rotate or swing to be in contact with the first sliding surface  38  of the base  10  due to their rounded profile. 
         [0073]    Above the insert first sliding surface  45 , the inserts are formed with insert walls with an angle of ascension much greater than the insert first sliding surface  45 . The upper insert walls  25  are preferably vertical. In the first preferred embodiment, when the inserts  7  are vertical and sitting at the bottom of the housing  35 , and in their constricted state, the upper insert walls  25  are located away from the upper walls of the housing  40  and in contact with the middle wall  56  of the housing or base  10 . 
         [0074]    As shown in  FIGS. 28-30 , the inserts  7  are generally formed with an inner bore defining arc  60  and an outer wall defining arc  61 . The outer wall defining arc  61  of each insert in the second preferred embodiment is preferably interrupted by an insert tab  28  that projects from the convex outer wall defining arc or edge  61 . The insert tab  28  is preferably formed as an integral part of the insert  7 , rather than as a separate part attached to the insert  7 . The insert tab  28  extends only partially down the outer wall  25  of the insert  7 . 
         [0075]    In the second preferred embodiment, the base has a top edge  63 . The top edge is preferably flat. The top edge  63  of the housing  10  and portions of the upper wall  40  are notched with a number of indentations  64  that closely match the tabs  28  on the inserts. The notches  64  extend downwardly to the notch ledges  65 . Each tab preferably fits in an indentation  64 , but does not extend outside the housing  10 . The interlock between the insert tabs  28  and the indentations  64  prevents the inserts from rotating around the central axis  39 . The interface between the tabs  28  and the indentations  64  also help to stabilize the inserts  7 , helping to keep them level especially when a threaded rod  4  is inserted into the inner bore  24 . 
         [0076]    The preferred embodiment of the insert tab  28  has a multiple stepped profile. The upper portion  66  of the insert tab  28  extends sufficiently away from the insert upper wall  25  to be received in the notch or indentation  64  of the upper wall  40  of the base  10  when the inserts are in their constricted orientation resting at the base of the housing  10 . A middle portion  67  of the insert tab  28  extends away from the insert upper wall  25  less than the upper portion of the insert tab  28 . The middle portion  67  extends sufficiently away from the upper wall  25  of the insert  7  that when the inserts  7  are in their constricted orientation or state the outer surface  68  of the middle portion  67  of the tab  28  interfaces with the upper wall surface  40  of the base  10  below the notch  64 . The insert tabs  7  are also formed with a lower portion  69  that angles towards the upper wall  25  of the insert  7  until the tab reaches the upper wall  25 , creating a ramped surface  70 . The ramped surface  70  of the lower portion  69  of the insert tab  28  is preferably planar. This represents the lower extent of the insert tab  28 . The insert tabs  28  are able to at least partially fit in the notches  64  in the wall of the housing  10 . The insert tabs  28  have a circumferential extent or width that is less than the circumferential extent of the notches  64  or indentations in the base  10 . 
         [0077]    The inserts  7  are formed so that when a threaded rod  4  is inserted into the anchor  1  and pushes the inserts  7  upwardly, the outer wall or surface  68  of the middle portion  67  of the insert tabs  28  can be received in the notches  64  in the housing above the ledge  65 , and the outer wall or surface  70  of the lower portion of the insert tab  69  can contact the edge  71  of the ledge  65  of the housing notch  64  where it interfaces with the upper wall  40  of the housing  10 . The upper portions  66  of the insert tabs  28  extend sufficiently toward the housing wall  40  such that the upper portions  66  of the tabs  28  are received in the notch  64  when the inserts  7  are in their constricted state and resting at the base of the housing  10 , but the upper portions of the tab  66  are spaced sufficiently from the housing  10  that when the inserts  7  are pushed upwardly and tipped or translated outwardly the upper portions  66  of the insert tabs  7  can be inserted further into the notches  64 . 
         [0078]    In the second preferred embodiment, a compression member  9  is preferably located between the inserts  7  and cap  46  which is attached to the top of the housing or base  10 . In the second preferred embodiment the cap  46  is formed with an annular descending, shouldered flange  72  that can clamp onto the annular flange  73  of the base  10 . The cap  46  is so large that it extends over the heads of the fasteners  47 . The fastener heads  47  are in contact with the bottom of the flange  74  of the base  10  to translate driving forces applied to the top of the cap  49  which rests on the flange  74  of the base  10  to the fasteners  3 . The fasteners  3  are formed with pointed tips  50  for making it easier to drive them into the form  2 . Bosses and tabs  51  in the holder  52  hold the fasteners  51  to the housing. The cap  46  receives a plate  75  made of metal that helps to translate the force exerted on the cap  46  to the head flange  33  of the base  10 . The cap  46  is preferably made of plastic. 
         [0079]    The first sliding surfaces  38  of the housing are preferably set at the same angle as the thread angle of the rod  4 . 
         [0080]    In the preferred embodiments, the inserts  7  are made with flat tops  23  and in one preferred embodiment are compressed by a member  9  with a flat surface so that it allows the tie rods  4  to be inserted with a minimal risk of jamming the take-up device  1  because the inserts  7  are held in place by a flat, hard washer  30  above, which interfaces with the flat surfaces  23  at the top of the inserts  7  to stabilize them as they expand away from and constrict towards the central vertical axis  39  of the anchor  1 . 
         [0081]    The top surface  23  of the inserts  7  need not be planar, but it is generally advantageous to maximize the area of the top surface  23  because the top surface  23  is where the inserts are pushed down by compression member  9  which helps to prevent the inserts  7  from rotating too far out of their upright orientation when the tie rod  4  pushes them upwardly and outwardly when it is installed, and thus the inserts  7  are appropriately positioned to grasp the tie rod  4  as firmly as possible when the tie rod  4  is in tension. 
         [0082]    In use, the concrete anchor  1  is placed on a form  2  at a selected position, and then the top  5  of anchor  1  is hammered to drive the fasteners  3  into the form  2  until the bottom  6  of the anchor  1  bears against the top surface  36  of the form  2 . Concrete  37  is then cast around the concrete anchor  1 . The hardened concrete cast around the anchor  1  can be considered a first structural member to which the rod  4  is connected by means of the anchor  1 . After the concrete  37  has hardened, the form  2  is removed. Thereupon, the interior bore  24  is exposed through the concrete slab  37  as well as the bottom  35  of the housing or base  10 . The housing or base  10  can be colored to indicate the size or sizes of rods  4  that can be received by the concrete anchor  1 . The portions of the fasteners  3  which project beyond the bottom  35  of the base or housing  10  should be cut off to prevent them from being a hazard. A suspension bolt or threaded rod  4  can be then inserted into and grasped by the concrete anchor  1 , and various building members can be suspended from the threaded rod  4 .