Patent Publication Number: US-11655846-B2

Title: Snap nut concrete anchor assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Divisional of U.S. patent application Ser. No. 15/948,131, filed Apr. 9, 2018, which claims priority from EP Patent Application No. EP17166593.8, filed Apr. 13, 2017, and EP Patent Application No. EP17170866.2, filed May 12, 2017 the disclosures of which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to anchors for use in concrete substrates. 
     BACKGROUND OF THE INVENTION 
     Concrete structures are typically formed from concrete substrates, being either the type made off site (commonly known as pre-cast concrete substrates) or the type made on site (commonly known as cast in place (CIP) concrete substrates). Both types of concrete substrates may be reinforced with metal of other suitable materials depending on their intended application. It is often necessary to attach fixtures and fittings to concrete substrates, the nature of which might vary according to the type of structure. For instance, many buildings have floors or walls made from concrete panels from which ducts or other items may be suspended, bridges may include concrete portions from which signage and other items must be hung, and so on. This often requires an anchor to be secured to or within the concrete substrate such that the fixtures and fittings can be mechanically fastened to the anchor. The anchors of interest here are those which are installed during production of the substrate, rather than those retrofitted to the concrete substrate after production. The general process for installing these anchors includes the steps of setting out a form board, mounting the anchor in the desired position on the form board, securing the anchor to the form board, pouring concrete over the form board and the anchor, removing the form board from the set concrete so as to reveal at least a portion of the anchor in the underside of the concrete substrate. The revealed portion of the anchor may expose a receptacle into which a threaded rod may be received and secured. In other words, these anchors comprise an anchor point accessible from the underside of the concrete substrate and which typically take the form of a threaded bore into which a bolt or threaded shaft can be fastened. 
     Because different structural designs require different diameter bolts or threaded shafts, numerous designs have been proposed such that a single threaded bore structure mentioned above is able to accommodate different sized/diameter bolts or threaded rods. Typically, such threaded bore structures embody some sort of separable split nut concept in which a threaded bore includes at least two separable threaded parts or portions. The parts are able to be forced apart radially from a central longitudinal axis of the rod or bolt and then are biased back together so that interior female threads of the bore portions complementarily engage the external male threads of the rod or bolt. Many of these designs allow a rod or bolt to be installed by simply forcing the rod or bolt axially into the bore portions spreading the bore portions apart and then allowing the bore portions to be axially biased radially inward (e.g., by a flexible biasing member) onto the rod or bolt. 
     At least U.S. Pat. Nos. 4,368,606 and 5,468,105 teach the biased split nut concept embodied in an anchor that is attachable to formwork (e.g., wooden formwork). U.S. Pat. No. 4,007,563 discloses an anchor for setting in metal decking. The present application also contemplates replacement of the female thread receptacle disclosed therein with the snap locking system described below. All three patents are incorporated by reference herein in their entirety. 
     While split nut designs provide a certain flexibility with axial installation and accommodation of multiple thread sizes, this structure can also present some reliability challenges. Specifically, mating between the threads of the rod and nut portions is important, so it is best when the alignment of the separate bore portions is maintained and it would be preferred if the user could have assurances that proper alignment of the portions and complete collapse of portions onto the rod or bolt has occurred. 
     It is therefore an object of the present invention to provide an anchor which is easy to install and whose integrity is not affected by careless installation. 
     BRIEF SUMMARY OF THE INVENTION 
     According to a first aspect of the invention, there is provided a base member connectable to a support member to form an anchor assembly mountable to a form board or metal decking on which wet concrete may be poured during formation of a concrete substrate, the base member includes a mounting portion for mounting the anchor assembly to the form board. The base member may also include a main guide having first and second generally opposed ends, the first end being open to facilitate insertion of the support member into the main guide. The main guide may also including a generally tubular body upstanding from the mounting portion. The tubular body may have an internal cross-section sized and shaped to correspond closely with the cross-section of the support member so as to create a snug fit between the main guide and the support member. 
     Advantageously the base member includes at least one reinforcement member to improve the rigidity and or strength of the main guide. The reinforcement member may comprise at least one web arranged between the main guide and the mounting portion and preferably spaced equidistantly around the main guide. 
     One type of reinforcement member may include at least one rib arranged axially and projecting inwardly. The at least one rib may add increased stiffness and lateral support between the main guide and the support member to resist inadvertent deformation and/or disassembly of those parts. The plurality of ribs circumferentially spaced around the main guide and each disposed between two neighbouring channels. 
     According to a second aspect of the invention, there is provided a cast in place anchor assembly comprising a base member as described above and a support member located in the main guide of the base member. The support member may include attachment means accessible through the second end of the main guide. For instance, the support member may comprise a shank having opposed first and second ends. 
     Specifically, the support member includes an outer housing, the outer housing being defined by a longitudinal axis, the outer housing including a wall, the outer housing also including a connector opening at a first end thereof for receiving the threaded shaft/shank, the outer housing further including an assembly opening at a second end opposite the first end thereof, the housing wall including an inner surface defining a bore space. 
     The support member further includes a bore assembly disposed in the bore space, the bore assembly including at least one female threaded bore portion the threads of which selectively engage threads of the shaft, the bore assembly further including a bias member for biasing the at least one female thread bore portion toward the longitudinal axis. A holding member is provided that prevents the bias member from moving the at least one female threaded bore portion toward the longitudinal axis. 
     The bore assembly may take two different configurations. In a first bore assembly configuration, the holding member prevents the at least one female threaded bore portion from moving toward the central longitudinal axis. Furthermore, in the first configuration the threaded shaft is inserted into the connector opening, to contact the holding member to release the at least one female threaded bore portion to move toward the central longitudinal axis and into biased contact with the threaded shaft to define a second bore assembly configuration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       By way of example only, embodiments of the present invention will now be described in detail, with reference being made to the accompanying drawings, in which: 
         FIG.  1 A  is a first perspective view of an anchor assembly of the present invention; 
         FIG.  1 B  is a side cutaway view of the anchor assembly of  FIG.  1    receiving a threaded shaft; 
         FIG.  2    is cross-sectional view of a support member of the anchor assembly of  FIGS.  1  and  2   ; 
         FIG.  3    is an exploded view of a locking assembly of the anchor assembly of  FIGS.  1  and  2   ; 
         FIG.  4 A  is top perspective view of the locking assembly of  FIG.  3    in a pre-snap assembled form; 
         FIG.  4 B  is a top perspective view of the locking assembly of  FIG.  3    assembled in the pre-snap configuration and positioned relative to a plug; 
         FIG.  4 C  is a top perspective view of the locking assembly of  FIG.  3    with a holding member in a post-snap configuration and bore portions configured just before snapping; 
         FIG.  5 A  is cross-sectional view of the anchor assembly of  FIGS.  1  and  2    in the pre-snap configuration and receiving a threaded shaft; 
         FIG.  5 B  is a cross-sectional view of the anchor assembly of  FIGS.  1  and  2    having received a threaded shaft in the post-snap configuration; 
         FIG.  6 A  shows a side view of a locking assembly of a second embodiment of an anchor assembly of the present invention in the pre-snap configuration; 
         FIG.  6 B  is a top perspective cut-away view of the locking assembly of  FIG.  6 A ; 
         FIG.  7 A  is cross-sectional view of an anchor assembly including the locking assembly of  FIGS.  6 A and  6 B  secured therein and set in the pre-snap configuration; 
         FIG.  7 B  is a cross-sectional view of the anchor assembly of  FIG.  7 A  with the locking assembly in the pre-snap configuration and a threaded shaft inserted through the locking assembly; 
         FIG.  7 C  is a cross-sectional view of the anchor assembly of  FIG.  7 B  with a holding member in the post-snap configuration and the bore portions positioned just before snapping; 
         FIG.  7 D  is a cross-sectional view of the anchor assembly of  FIG.  7 C  in the post-snap configuration with a lower jaw assembly engaging a first sized threaded rod; 
         FIG.  7 E  is a cross-sectional view of the anchor assembly of  FIG.  7 D  with the lower bore assembly in the post-snapped configuration and resting on the support member; 
         FIG.  8    is a cross-sectional view of the anchor assembly of  FIG.  7 A  with the upper bore assembly in the post-snapped configuration and the lower assembly resting on the support member; 
         FIG.  9    is a cross sectional view of a prior art deck anchor. 
         FIG.  10    is a cross-sectional view of an embodiment of an outer housing for use with the deck anchor of  FIG.  9   . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIGS.  1 A and  1 B  show an embodiment of an anchor assembly of the present invention, which is generally indicated as  100  and may receive a threaded shaft  50 ,  650  inserted in a direction D. Anchor assembly  100  includes a support member  210  to be supported within a base member  150 . Base member  150  may be mounted to a form board (not shown) for defining a poured concrete structure. Base member  150  may include a form engagement support  154  and a raised main guide  158  for receiving and positioning support member  210  relative to the form after assembly. Raised main guide  158  may be further reinforced by ribs or structural aids  160  that hold raised main guide  158  securely relative to base member  150 . Structural aids may come in various forms and may include channels  164  through which fasteners (e.g., nails) pass and then enter the form for securing anchor assembly  100  to the form. Also shown in  FIGS.  1 A and  1 B  is a plug  260  to be discussed in more detail below. 
       FIG.  2    shows a cross-section of support member  210  of anchor assembly  100 . Support member  210  includes an outer housing  205 . Outer housing  205  includes a wall  207  having an inner surface  209  and a central longitudinal axis A-A. Inner surface  209  defines a bore space  211 . A connector opening  203  is disposed at a first end  212  of outer housing  205 . An assembly opening  213  is disposed at a second end  214  of outer housing  205 . Inner surface  209  includes a lower wall surface  216  that defines a connector passage  128  through which a connector such as threaded rod  50  may be inserted into bore space  211  in an insertion direction D. 
     Inner surface  209  also includes a first tapered or first conical surface  230  that tapers to a narrower end toward first end  212 . First conical surface  230  defines a first conical space  231  and may be adjacent to lower wall surface  216 . Inner surface  209  may further include a second tapered or second conical surface  240 . Second tapered surface  240  defines a second conical space  241  and may be located on an opposite side of conical surface  230  from lower wall surface  216 . Therefore, bore space  211  includes connector passage  128 , first conical space  231 , and second conical space  241 . Like tapered surface  230 , conical surface  240  tapers to a narrower end toward first end  212 . 
     Inner surface  209  may further include an upper wall surface  250 . Upper wall surface  250  may be directly adjacent to second conical surface  240  or be separated by a third ledge  219 . Second conical surface  240  may be directly adjacent to first conical surface  230  or be separated by a second ledge  217 . First conical surface may be directly adjacent to lower wall surface  216  or be separated by a ledge  215 . 
     As mentioned above, at second end  214  of outer housing  205  is assembly opening  213 . Assembly opening  213  may receive a number of items (discussed in more detail below) internally to bore space  211  before being closed by a plug  260 . Plug  260  includes a periphery and the periphery includes a locking member or mechanism  262  such as a thread or threaded locking member. In addition, upper wall surface  250  includes a plug surface having a locking portion  252  such as a threaded portion. Locking mechanism  262  may be interlocked with locking portion  252  to secure plug  260  to upper wall surface  250 . Plug  260  may further include a shaped opening  265  for accommodating a tool that applies a rotational force to plug  260  as plug  260  is installed (e.g., threadably) to upper wall surface  250 . Plug  260  may further include projections  270  that extend into bore space  211  in a direction downward from second end  214  to first end  212 . 
       FIGS.  3  and  4 A- 4 C  disclose a locking device or locking mechanism that is disposed in bore space  211  before being closed in by plug  260 . Before installing plug  260  to support member  210 , a locking assembly  300  may be inserted into bore space  211  through assembly opening  213 . Locking assembly  300  includes a bore assembly  305  and a holding member  360 . Bore assembly  305  may include a biasing member  310  and at least one female threaded bore portion  330 A,  330 B. 
     Biasing member  310  may be made from any elastic material (e.g., rubber, metal) capable of surrounding at least a portion of the at least one female threaded bore portion  330 . In any case, bias member  310  need only be an elastic structure that urges (i.e., pulls or pushes) the threaded female portion toward a central longitudinal axis A-A of threaded rod  50  or of outer housing  205 . In other words, elastic member  310  may also be disposed between inner surface  209  and an outer surface of bore portions  330 . 
     Specifically, female threaded bore portions  330  include a concave threaded surface  334  and a tapered outer surface  338 . Tapered outer surfaces of one or more bore portions  330  may combine to at least partially define a conical or frusto-conical outer surface. Bore portion may include a top surface  328  and a bottom  345 . Bore portions  330  may further include a receptacle such as a groove  342  into which bias member  310  is securely received. Groove  342  may be in an outer surface of bore portion  330 , but (as mentioned above) alternatively need only surround a portion of bore portion  330  to contact and so urge bore portion  330  toward central axis A-A. Two or three or more female threaded bore portions  330  may be used. Furthermore, threads  334  need not be standard threads and a single thread or projection and corresponding groove may suffice to satisfy the definition of threaded with respect to threaded surface  334 . 
     Furthermore, bore portions  330  may include alignment tracks for maintaining alignment of bore portions  330  as bore portions  330  move toward and/or away from central longitudinal axis A-A in a plane perpendicular to axis A-A. For example, when bore assembly  305  includes two bore portions  330 , alignment tracks may include a projection  346  extending from a first bore portion  330 A being received (e.g., slidingly) in a track or groove  348  of the second bore portion  330 B and visa versa. In addition, multiple projections  346  may be employed on a bore portion to be received in multiple corresponding tracks  348  on an opposite or complementary bore portion. The same concept could be applied to three or more bore portions  330 . Such an inter-engagement between translating bore portions  330  minimizes wobble and may promote alignment between rod threads and bore portion threads. For example, if a plane is drawn through bore portions  330  and perpendicular to central axis A-A, the above described alignment mechanism will minimized wobbling of bore portions  330  about lines drawn in that plane through axis A-A. 
     Assembly  100  of the present invention transforms between two configurations. In a first configuration, threaded female surfaces  334  of one or more bore portions  330  are separated to a radius or radial distance (measured from or relative to A-A) larger than the external radius of threaded rod  50 . In the first pre-snap configuration, threaded shaft  50  may pass axially in and out of threaded surfaces  334  without rotation. In a second configuration, the one or more bore portions  330  are released to be biased against or onto threaded rod  50  to prevent rod  50  from axial movement relative to support portion  210  except by rotation. 
     As mentioned above locking assembly  300  includes a bore assembly  305  and a holding member  360  which are both received in bore space  211  through assembly opening  213 . Holding member  360  includes inward external projections  364  and inward internal projections  368 .  FIG.  4 A  shows locking assembly  300  as it would be assembled in the first pre-snap configuration. In this arrangement, inward external projections  364  may be tapered and extend downward along an outer periphery of bore assembly  305 . By this tapering and engagement of projections  364  against surface  209 , inward external projections  364  tend to self-center holding member  360  relative to bore assembly  305  and central longitudinal axis A-A. 
     At the same time, internal projections  368  are positioned between end portions  447 ,  449  of bore portions  330  to hold bore portions  330  in a relatively separated configuration relative to the post-snap configuration. In this pre-snap configuration, threads  334  of bore portion  330  are disposed at a further distance from central axis A-A than the external threads of threaded shaft  50 . 
       FIGS.  4 B and  4 C  show two configurations of holding member  360 . In a first pre-snap configuration, shown in  FIG.  4 B , plug  260  sits installed in outer housing  205  (not shown). Downward projections  270  of plug  260  extend toward bore portions  330  and may contact an upper portion  328  of bore portions  330 . Projections  270  may surround holding member  360  and define a surrounded holding space  410  (shown in  FIG.  4 A , but best seen in  FIG.  7 A ).  FIG.  4 C  shows how holding member  360  is able to be slid axially toward plug  260  and into the holding space  410  between projections  270 . Bias member  310  maintains a radially inward tension on bore assembly  305  except that an upward force on holding member  360  relative to bore assembly  305  may move holding member  360  relative to bore assembly  305  until holding member  360  is no longer between bore portions  330 . Bias member  310  is then no longer prevented from moving bore portions  330  toward central axis A-A, so they snap into the post-snap configuration. Projections  270  are sufficiently long to ensure that holding member  360  can move a sufficient distance in the axial direction toward plug  260  that internal projections  368  are no longer between and able to separate bore portions  330 . While holding member  360  is being slid, projections  270  prevent bore portions  330  from also moving axially toward plug  260 . Until completely removed, internal projection  348  prevent bore portions  330  from moving radially toward central axis A-A.  FIG.  4 C  essentially shows the transition instant between the two configurations in which internal projections  348  is removed from between bore portions  330 . 
       FIGS.  5 A and  5 B  show cross-sectional views of support member  210  with plug  260 , bore assembly  305 , and a holding member  360  installed in bore space  211 . Specifically,  FIG.  5 A  shows locking assembly  300  in the first pre-snap configuration. A threaded shaft  50  may be inserted into connector opening  203 . Threaded rod  50  may then extend between threads  334  of bore portions  330  until a lead end of threaded rod  50  contacts an under portion of holding member  360 . As bias member  310  urges bore portions  330  together and as internal projections  348  are squeezed between bore portions  330 , friction is developed between bore portions  330  and holding member  360 . Threaded rod  50  overcomes that reactionary frictional force as it moves/slides holding member  360  axially from the pre-snap to the post-snap configurations.  FIG.  5 B  shows locking assembly  300  in the second post-snap rod locked configuration. In this configuration, threads  334  engage shaft threads  52  of threaded fastener  50  to lock threaded shaft  50  in an axial position relative to outer housing  205 . 
     In addition to the biasing force of biasing member  310 , outer housing  205  provides biasing force to urge bore portions  330  against threaded shaft  50 . In the first pre-snap configuration, holding member  360  may sit on a first ledge  219  of inner surface  209 . Bore portions  330  may sit on a second ledge  217  and within second tapered surface  240 . The outer radius of projections  364  of holding member  360  may be larger than the inner radius of the third ledge  219  so that ledge  219  forms a stop to prevent holding member  360  from moving past third ledge  219  axially toward first end  212 . Similarly, the bottom outer radius of bore portions  330  in the first pre-snap configuration is larger than the inner radius of second ledge  217  so that in the first pre-snap configuration, second ledge  217  acts as a stop to prevent bore portions  330  from moving axially past second ledge  217  in the direction of first end  212 . 
     After holding member  360  is axially dislodged from between bore portions  330  by threaded rod  50 , bore portions  330  collapse inward onto threaded member  50  due to the inward biasing force of biasing member  310 . In the collapsed configuration, the outer diameter of bottom  345  of bore portions  330  is smaller than the inner diameter of second ledge  217 . Therefore, in the second post-snap configuration, outer surface  338  of bore portions  330  may move axially past second ledge  217  into first space  231  and wedge onto first tapered surface  230 . As discussed above, outer surfaces  338  of bore portions  530  may be tapered or conical to complement the first and second tapered conical surfaces  230 ,  240  of inner surface  209  of outer housing  205 . Therefore, surface  230  and surface  240  may be generally parallel to each other or have generally the same angle relative to axis A-A. However, outer walls  338  of bore portions  330  may be generally complementarily angled or parallel to one or both of these surfaces  230 ,  240  to generate a wedging effect between surfaces  230 ,  240  and  338 . 
     In the second post-snap configuration, shown in cross section in  FIG.  5 B , bore portions  330  collapse onto threaded rod  50  and both may move axially toward first end  212  until tapered surface  338  of bore portion  330  engages complementary tapered surface of first conical surface  230 . If an axial load is applied to threaded rod  50  in the direction of first end  212 , threads  52  of threaded rod  50  urge threads  334  of bore portion  330  in the same direction. Therefore bore portions  330  are urged toward first end  212  and first conical surface  230  in turn forces bore portions  330  axially inward toward central axis A-A and toward shaft  50 . Therefore, an axial load on rod  50  toward first end  212  results in a forcing together of bore portions  330  to further lock threaded fastener  50  axially relative to outer housing  205 . As a result, when outer housing  205  is secured in cured concrete, threaded rod  50  is secure axially in outer housing  205  so that is can be axially removed from outer housing  205  only by rotation. 
       FIGS.  6 A and  6 B  show a locking assembly  600  similar to locking assembly  300  in  FIGS.  4 A- 4 C . Locking assembly  600  includes a holding member  660  and a bore assembly  605 . Holding member  660  is similar to holding member  360  and includes an internal projection  668 . Bore assembly  605  includes an upper bore assembly which includes bore portions  638 A and  638 B. Bore assembly  605  also includes a lower bore assembly which includes bore portions  639 A and  639 B. Upper and lower bore assemblies are similar to bore assembly  305  and each include a radial groove for respectively accommodating bias members  610 A and  610 B for the same purpose as disclosed above in bore assembly  305 . Upper and lower bore assemblies also respectively include concave or female threads  635  and  634 . Threads  634  and  635  complementarily accommodate male threads of different diameters. In other words, threads  634  and  635  may have diameters different from each other. 
     Upper and lower bore assemblies may also include one or more pairs of cooperating and corresponding alignment mechanisms similar to the mechanisms described for bore assembly  305  above. Specifically, each upper and lower assembly may include one or more pairs of projections  646  that correspond to grooves or tracks  648  in the other bore portion. Furthermore, the grooves and/or tracks may be tapered so that the cross-sectional area of projection  646  decreases as it cantilevers away from the bore portion and the cross sectional area of the groove increases toward where the projection enters the groove. The tapered arrangement ensures adequate compliance during snapping between configurations and alignment compliance is most accurate as the bore portions  638 A,  638 B and  639 A,  639 B are forced closer together. 
     Bore assemblies  638 A,  638 B and  639 A and  639 B may be stackable on each other.  FIG.  6 B  shows an upper engagement portion  684  of lower bore assembly  639 B and  639 A includes a top and an inner radial bearing surface  685 . A lower portion of upper bore assembly  638 A,  638 B includes at a bottom, a holding projection  680  on which is an outer radial surface  682 . The bottom of upper bore assembly  638 A,  638 B sits on the top of lower bore assembly  639 A and  639 B. In addition, holding projection  680  extends axially downward past a top of lower bore assembly  639 A and  639 B and outer radial bearing surface  682  of upper bore assembly  638 A and  638 B may engage inner radial bearing surface  685  of lower bore assembly  639 A and  639 B when the bottom of upper bore assembly  638 A,  638 B sits on the top of lower bore assembly  639 A and  639 B in the first pre-snap configuration. 
     In a similar manner as holding member  360  above, holding member  660  is employed to separate bore portions  638 A,  638 B,  639 A, and  639 B in the first pre-snap configuration. Holding member  660  includes an axially downward projection  668  which may radially engage an inwardly facing surface  633  of top portion  631  of upper bore assembly  638 A and  638 B. Inwardly facing surface  633  may include a receptacle for complementarily receiving an outwardly extending locking projection of downward projection  668 . The locking relationship between the projection and receptacle may more securely holding member  660  to upper bore portions  638  to ensure that no snapping occurs until intended engagement by threaded shaft  650 A. Holding portion  660  holds upper bore portion sufficiently separated that an inner radius of concave female threads  635  of upper bore portion  638 A,  638 B is larger than an outer radius of threaded rod  650 A to be inserted into locking assembly  600 . When holding member  660  separates upper bore portions  638 A and  638 B and therefore threads  635 , holding member  660  also separates lower bore portions  639 A and  639 B and therefore internal threads  634  in a radial position that is larger than external threads of threaded shaft  650 A. 
     In the first pre-snap configuration, holding portion  660  separates lower bore assembly via upper bore assembly utilizing the structure described above. Specifically, when upper bore assembly  638 A,  638 B is held in the pre-snap configuration by holding member  660 , outer radial surface  682  engages inner radial bearing surface  685  to limit the inward axial travel of lower bore assembly  639 A,  639 B. Therefore, the inner radial position of both sets of threads  634  and  635  is larger than the outer radial position of threaded rod  650 A. This means that the radial position limiting imposed by holding member  660  on threads  634  and  635 , ensures that threaded shaft  650 A can be inserted into bore assembly  600  without engagement with or interference by threads  634 ,  635 . Threaded Rod  650 A will therefore experience uninhibited axial advancement until it contacts holding member  660 . 
       FIGS.  7 A and  7 B  show a cross-sectional view of locking assembly  600  secured in an outer housing  606  trapped between tapered wall surface  630  and a bottom portion of plug  662 . As with the single bore assembly  305  discussed above, in the pre-snap configuration of  FIG.  7 A , a clear passage is available through connector opening  603 , through upper and lower bore assemblies, and up to holding portion  660 .  FIG.  7 B  shows threaded member  650 A inserted axially in through and past a passage defined by threads  634 ,  635  and into engagement with a lower side of holding member  660 .  FIG.  7 C  shows threaded rod  650 A advanced axially to push holding member  660  into a vacant space  440  in plug  662 . Downward projection  663  of plug  662  prevents upper bore assembly  638 A,  638 B from moving upward axially with holding portion  660  as threaded rod  650 A forces it up into the vacant space. Specifically,  FIG.  7 C  shows both upper and lower bore assemblies the instant before they are biased toward central axis A-A by bias members  610 A and  610 B. 
       FIG.  7 D  shows upper and lower bore assemblies collapsed or snapped toward and biased against threaded rod  650 A. Specifically, based on a threaded rod  650 A of a specific or certain size (e.g., ⅜″), threads  634  of lower bore assembly  639 A,  639 B engage snuggly and complementarily with threads  652 A of threaded rod  650 A. On the other hand, threads  635  of upper bore assembly  638 A,  638 B do not engage or do not engage threads  652 A snuggly because a radius of rod  650 A is such that when portions  638 A and  638 B come together and engage each other (as far toward axis A-A as possible), the resulting inner thread radius (of threads  635 ) is larger than the thread rod  650 A outer thread radius. In other words, by contact with itself (i.e., upper bore portion assembly  638 A,  638 B) threads  635  of upper bore portion assembly  638 A,  638 B have a minimum radius that is larger than the max radius of rod threads  652 . 
       FIG.  7 E  shows threaded rod  650 A engaged with lower bore assembly  639 A,  639 B and rod  650 A lowered with bore assembly  605  attached thereto. Therefore, when threaded rod  650 A is lowered, lower bore assembly  639 A,  639 B is also lowered until it contacts tapered wall surface  630 . Threaded rod  650 A is secured axially to lower bore assembly  639 A,  639 B and is not further able to be retracted from anchor  100  except for axial movement by rotation. With respect to load path, a downward load applied to threaded rod  650 A is transferred to rod threads  652 A, then to threads  634  of lower bore assembly  639 A,  639 B, then to lower bore assembly  639 A,  639 B, then to outer housing  606 , and then to the surrounding cured concrete. 
       FIG.  8    shows a threaded rod  650 B that is of a different size/diameter (e.g., a larger ½″ diameter) from threaded rod  650 A. Threaded rod  650 B is inserted into anchor  100  in the same manner as threaded rod  650 A is shown inserted in  FIG.  7 C . However, because threaded rod  650 B is of a larger diameter, upper and lower bore assemblies  638 A,  638 B,  639 A, and  639 B collapse or snap toward rod  650 B differently. Specifically, threads  635  of upper bore assembly  638 A,  638 B collapses onto threads  652 B to create a snug complementary threaded engagement. In other words, when the smaller diameter rod  650 A was inserted, threads  635  were unable to reach threads  652 A of rod  650 A, but threads  635  are now able to reach the threads  652 B of the larger diameter rod  650 B. On the other hand, when the larger diameter rod  650 B is inserted, the threads  634  of lower bore assembly  639 A,  639 B may engage rod threads  652 B, but not snuggly and complementarily. This is because as discussed above, threads  634  and  635  may have different diameters for complementarily meshing or engaging with different sized male threaded fasteners. In other words, lower bore portions  639  may have thread sized to snuggly accommodate a shaft with a smaller radius than shaft  650 B. Therefore, Axial locking of larger rod  650 B is accomplished by the thread inter-engagement between rod  650 B and upper bore assembly  638 A,  638 B. With regard to load path, after the bore assembly  605  snaps to secure itself to rod  650 B, a downward load on rod  650 B is transferred through rod threads  652 B, then to bore portion threads  635 , then to upper bore portion  638 A,  638 B then, to lower bore portion  639 A,  639 B, then to outer housing  606 , and then to the cured concrete. 
     After holding member  360 ,  660  is removed from its holding function by threaded rod  50 ,  650 , bore portions  330 ,  630  are radially forced suddenly or biasingly toward central axis A-A. Sudden impact between bore portion  330 ,  360  and threaded rod  50 ,  650  during installation may release or generate enough sound energy or audible energy to enable an installer to detect (e.g., by hearing) the triggering of the bore portions against threaded rod  50 ,  650 . Furthermore, while the installer is holding the threaded rod  50 ,  650  during installation, enough impact energy may be transferred through threaded rod  50 ,  650  for an installer to feel vibration energy transferred (from the potential energy in bias members  310 ,  610 ) through the threaded rod  50 ,  650  to notify the installer that bore portions  330 ,  630  have triggered. 
     The snap-nut assembly described above may be utilized in any anchoring system in which it is desired to axially secure a shaft such as a threaded shaft to a support structure. Therefore, the snap-nut assemblies of  FIGS.  4 A and  6 A  may be integrated into various anchoring systems including metal deck anchoring systems such as described in U.S. Pat. No. 4,007,563 to Nakagawa. For example Nakagawa&#39;s  FIG.  3    shows a cross section of the deck anchor installed on a deck plate. A male thread  1   b  extends downward and first end of a female threaded nut  6  is threaded onto male thread  1 B. A second end of female thread  6  is exposed for receiving a threaded rod for anchoring the threaded rod to the decking  10 . 
       FIG.  10    shows a modified support portion  210 B including extended walls of upper wall surface  250  including an extended locking surfaces  252 . Locking mechanism  262  of plug  260  is installed in a lower portion with locking surface  252  so that an upper female threaded portion of locking surface  252  is exposed. In this form, support member  210 B may be combined with Nakagawa&#39;s deck anchoring device to provide a deck anchor with the claimed snap-nut anchoring system. Specifically, the device of  FIG.  10    may be substituted for Nakagawa&#39;s internally threaded nut  6  to combined Nakagawa&#39;s  FIG.  3    with the claimed snap-nut locking anchor mechanism. Here, the exposed upper female locking portion  252  may be simply threaded onto male thread  1   b . A threaded rod may then be locked in the snap-nut locking mechanism as described above.