Patent Publication Number: US-8992147-B2

Title: Drop-in anchor

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 12/813,109, filed Jun. 10, 2010, titled “Drop-In Anchor,” which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The subject matter disclosed herein relates to anchor systems. More specifically, the subject disclosure relates to drop in anchors. 
     BACKGROUND 
     Drop-in anchors for use in, for example, fastening items to masonry, typically include a sleeve, which is placed in a pre-drilled hole. A plug is driven into an expandable portion of the sleeve which, when expanded, secures the sleeve in the hole. Items may be secured to the masonry via a threaded end of the sleeve opposite the expandable portion of the sleeve. 
     In typical drop-in anchors, the plug is frustoconically shaped thereby providing an outer surface substantially matching an inwardly tapering inner wall of the sleeve. This has always been, understandably thought to be the most efficient configuration for a drop-in anchor as the angled surfaces have been understood to work with each other to garner the desired effect while using the angle to make insertion as easy as it can be. Nevertheless, drop-in anchors of the prior art require substantial setting force, normally obtained by the application of a relatively large number of blows with a sledge hammer. The art would well receive a drop-in anchor requiring a lower setting force to set the plug and expand the sleeve. 
     SUMMARY 
     A retainer for a drop-in anchor includes a durable, moisture resistant member insertable into a sleeve of a drop-in anchor and configured to be retained in the sleeve by one or more threads disposed in the sleeve to prevent inadvertent removal of a plug from the sleeve. 
     A drop-in anchor assembly includes a tubular sleeve having a first end including one or more internal threads, and an expandable second end. A plug is insertable in the sleeve such that when the plug is driven into an installed position in the sleeve the second end expands. A retainer formed of a durable moisture-resistant material is insertable in the sleeve behind the plug, and is configured to be retained in the sleeve by the one or more threads and prevent inadvertent removal of the plug from the sleeve. 
     A method of assembling a drop-in anchor includes providing a tubular sleeve, the sleeve having a first end including one or more internal threads, and an expandable second end, and inserting a plug into the first end of the tubular sleeve. A durable, moisture-resistant retainer is inserted into the first end behind the plug. An outer periphery of the retainer is engaged with the threads to prevent inadvertent removal of the plug from the sleeve. 
     These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a cross-sectional view of an embodiment of a drop-in anchor; 
         FIG. 2  is a cross-sectional view of an embodiment of a drop-in anchor with the plug in an installed position; 
         FIG. 3  is a cross-sectional view of an embodiment of a drop-in anchor including a retainer; 
         FIG. 4  is a cross-sectional view of another embodiment of a drop-in anchor including a retainer; 
         FIG. 5  is a plan view of an embodiment of a retainer; 
         FIG. 6  is a cross-sectional view of an embodiment of an installation tool; 
         FIG. 7  is a cross-sectional view of an embodiment of an installation tool configured for drilling; 
         FIG. 8  is a cross-sectional view of an embodiment of an installation tool configured to drive a plug; and 
         FIG. 9  is a cross-sectional view of another embodiment of a drop-in anchor. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
       FIG. 1  illustrates an improved drop-in anchor  10 . The anchor  10  includes a sleeve  12 . The sleeve  12  is substantially tubular and is radially expandable at an expansion end  14 . To achieve the expandability, the sleeve  12  includes one or more expansion openings  16  or other similar structure allowing diametric increase of the sleeve at the expansion end  14  extending from the expansion end  14  partially along a length  18  of the sleeve  12 . An inner wall  20  in one embodiment of the sleeve  12  includes threads  22  at a threaded end  24  opposite the expansion end  14  to receive a threaded fastener (not shown) to secure desired items to the anchor  10  once the anchor is installed in, for example, concrete masonry. It is to be understood that although it is common for drop-in type anchors to bear box threads (i.e. threads at an inside surface of the sleeve  12 ) it is also possible to place the threads  22  at an outside surface of the sleeve  12  providing the sleeve  12  is configured to extend beyond a surface of the masonry (proud of the surface of the masonry) when installed. 
     The anchor  10  includes a plug  26 , which is insertable into the sleeve  12  from the threaded end  24 . In some embodiments, a diameter of the sleeve  12  at the expansion end  98  is such that the plug  26  is only insertable in the sleeve  12  from the threaded end. An inner diameter  28  of the sleeve tapers in an expansion portion  98  or decreases at a sleeve angle  30  from the threaded end  24  to the expansion end  14  so that the plug  26  is in an interference fit with the sleeve  12  in the expansion portion  98 , so that when the plug  26  is driven toward the expansion end  14 , the expansion portion  98  expands to secure the sleeve  12  in the concrete masonry. In some embodiments, the expansion end  14  includes a substantially cylindrical end portion  96  having a diameter  28 , The plug  26  has a tip end  32  located closest to the expansion end  14  and a head end  34  located closest to the threaded end  24 , and in some embodiments may be substantially cylindrical from the tip end  32  to the head end  34 . In other embodiments, the plug  26  has a slight taper at a plug angle  36  from the head end  34  to the tip end  32 . 
     The plug angle  36  and the sleeve angle  30  are substantially dissimilar, with the sleeve angle  30  being greater than the plug angle  36 , such that a contact area  38  between the plug  26  and the sleeve  12  is reduced over that of prior art drop-in anchors. In some embodiments, the contact  38  may be substantially an annular, planar contact  38 . A difference between sleeve angle  30  and the plug angle  36  determines the size of the contact area  38 . In some embodiments, the difference between the sleeve angle  30  and the plug angle  36  is about 1 degree or greater, for example 1.5 degrees. This assures a minimal contact area  38  between the sleeve  12  and the plug  26 . Reduction of the contact area  38  reduces friction between the sleeve  12  and the plug  26  thereby reducing an amount of force required to set the plug  26  in an installed position  40 , shown in  FIG. 2 . Once the plug  26  is driven to the installed position  40 , however, the difference between the sleeve angle  30  and the plug angle  36  is substantially zero due to the deformation of the expansion portion  98 . In some embodiments, the tapered portion of the plug  26  is located at the cylindrical end portion  96  when in the installed position  40  so as not to limit full expansion of the sleeve  12  when the plug  26  is driven to the installed position  40 . 
     In some embodiments, the friction is reduced enough such that the plug  26  may be driven into the installed position  40  by a number of blows with a sledge hammer or even a standard 16 or 20 ounce hammer that is substantially fewer than was necessary in the prior art. Moreover, in some embodiments, a conventional rotary hammer drill (not shown) maybe employed to successfully set the drop-in anchor without the use of any other driving means. It is to be appreciated, however, that any suitable setting tool may be utilized. These embodiments may include those between about ¼″ and ¾″ in diameter. Further, because of the lack of taper in the plug  26 , when the plug  26  is driven toward the expansion end  14  the plug  26  deforms the material of the expansion portion  98  directly radially outwardly in contrast to prior art tapered plugs  26  in which the sleeve material bends around the taper of the plug. This results in an expanded sleeve  12  which has a substantially linear outer surface of the expansion portion  98 . This linear outer surface sleeve  12  increases ultimate loads which the drop-in anchor  10  is capable of withstanding, when compared to a prior art anchor having a tapered plug of similar maximum diameter. 
     Referring again to  FIG. 1 , the tip end  32  of the plug  26  may include a chamfer  42 . The chamfer  42  is included to encourage the plug  26  to move into the installed position  40  more easily by preventing the plug  26  from snagging on the inner wall  20  of the sleeve  12  when driven. The chamfer  42  is small enough such that no expansion is lost due to the reduction in diameter of the plug  26  due to the presence of the chamfer  42 . Further, in some embodiments, the plug  26  is driven into the installed position  40  such that chamfer  42  is located in the cylindrical end portion  96  to preserve maximum expansion of the sleeve  12 . 
     Referring now to  FIG. 3 , some embodiments include a retainer  44 . The retainer  44  is inserted into the sleeve  12  from the threaded end  24  after the plug  26  is inserted, to prevent the plug  26  from inadvertently being removed from the sleeve  12  before the plug  26  is driven to set the drop-in anchor  10 . More specifically, since the plug  26  is loosely deposited in the sleeve  12 , it is not only possible but common for the plug  26  to fall out of the sleeve  12  either in shipping, storage, or just prior to deployment. Such departure of the plug  26  is at least a nuisance and possibly could impact efficiency or success at a job site if the plug  26  is not easily found. The retainer  44  is positioned within the sleeve  12  so that exit of the plug  26  is prevented and may in some instances be urged into the sleeve  12  to a depth therein that prevents or impedes movement of the plug  26  to any appreciable degree. Limitation of movement of the plug  26  as such has the added benefit of reducing noise associated with jostling of the sleeve  12  and plug  26 . 
     The retainer  44  is formed from a relatively durable material that includes at least a property of moisture resistance. In one embodiment the material is a plastic material, for example, polyethylene, although metal, wood, rubber or other suitable materials may be substituted. The retainer  44  is molded or otherwise formed, such as for example stamped, punched, extruded, cut, etc. In some embodiments, the retainer  44  is substantially disc-shaped while in other embodiments other shapes such as part spherical, square, triangular, pentagonal, lenticular, etc. can be substituted without departure from the scope of the disclosure hereof. Ultimately any shape capable of being positioned relative to the sleeve  12  and plug  26  that will prevent or substantially deter plug  26  exit from the sleeve  12  is contemplated. As shown in  FIG. 3 , the retainer  44  is configured such that an outer periphery  46  of the retainer  44  engages the threads  22  of the sleeve  12  when the retainer  44  is inserted into the sleeve  12 . It is to be appreciated, however, that in other embodiments the periphery  46  of the retainer  44  may frictionally engage a thread  22  crest to secure the retainer  44  in the sleeve  12 . 
     Some embodiments of the retainer  44  include a protrusion  48  extending out of a plane defined by the periphery  46  of the retainer  44  which in some embodiments is located substantially at a center  50  of the retainer  44 . As shown, the protrusion  48  may be frustoconically shaped. In other embodiments the protrusion  48  may have other shapes, for example, as shown in  FIG. 4 , the protrusion  48  may be at least part spherical. Referring to  FIG. 5 , in some embodiments the retainer  44  includes one or more fingers  50  extending outwardly from a center portion  52  of the retainer  44 . In the embodiment of  FIG. 5 , the retainer  44  includes four fingers  50  equally spaced around the retainer  44 . It is to be appreciated that in other embodiments, other quantities of fingers  50  may be included, for example, three, six or eight fingers  50 . The fingers  50  make the outer periphery  46  of the retainer  44  more pliable allowing for surer engagement of the retainer  44  to the helical threads  22  of the sleeve  12 . In addition, because structure of the fingers  50  necessarily form a break in the material, the crossing of threads  22  of the sleeve  12  by the retainer  44  is not required. Rather, the fingers  50  can each fully engage in a thread  22  trough without extending over a thread  22  crest. The fingers  50  further decrease an amount of force necessary to set the plug  26  with the retainer  44  installed relative to a retainer  44  without fingers  50 . The astute reader will also appreciate based upon the foregoing that a single break in the periphery  46  of the retainer  44  will also achieve the result of full engagement and avoidance of thread  22  crest crossing. 
     Referring now to  FIG. 6 , some embodiments of the drop-in anchor  10  are configured to be installed by a unique installation tool  54 . The installation tool  54  includes a drill bit  56 . The drill bit  56  includes a shaft  58  disposed at a connection end  60 , which is configured to be installed in a chuck (not shown) of, for example, a conventional rotary hammer drill (not shown). A drill end  62  is configured as a drill, with a pointed tip  64  and flutes  66 . A bit collar  68  is located between the drill end  62  and the connection end  60 . 
     The installation tool  54  includes a tool sleeve  70  which is securable over the drill bit  56  and includes a tool pocket  76  at a first end  78  of the tool sleeve  70 . The tool pocket  76  is a substantially tubular, and in some embodiments, cylindrical structure into which the drill bit  56  is insertable and securable. To secure the tool sleeve  70  to the drill bit  56 , some embodiments include one or more elements at the bit collar  68 , for example, one or more slots  72  which are engageable with one or more protrusions  74  (pins, bars, etc.) of the tool sleeve  70  extending inwardly into the tool pocket  76 . The one or more slots  72  may be of any shape along their length so as promote retention of the one or more protrusions  74  therein, for example, j-shaped, z-shaped, s-shaped, etc. In some embodiments, the protrusion and slot arrangement may be substantially reversed, with the protrusions  74  extending outwardly from the bit collar  68  and receivable in a slot  72  disposed in the tool sleeve  70 . While one slot  72  is shown, it is to be appreciated that other quantities of slots  72  and protrusions  74 , for example, two, three or more slots  72  and protrusions  74  may be used. Further, some embodiments include a biasing member  94  located in the tool pocket  76  to bias the drill bit  56  away from the tool sleeve  70  to aid in securing the protrusions  74  in the slots  72 . The biasing member  94  shown is a block of resilient material, for example, rubber. It is to be appreciated that other types of biasing members  94 , for example, a spring located in the tool pocket  76  are also contemplated within the present scope. While a protrusion and slot connection arrangement between the tool sleeve  70  and the drill bit  56  is described herein, it is merely exemplary and other connection arrangements are contemplated within the scope of the present disclosure. The tool sleeve  70  includes a setting tool tip  80  located at a second end  82  of the tool sleeve  70 . The tool tip  80  is, when the tool sleeve  70  is installed over the drill bit  56 , used to drive the plug  26  into the installed position  40  thus expanding the sleeve  12 . 
     The installation tool  54  is utilized to install a drop-in anchor  10  as shown in  FIGS. 7 and 8 . Initially, the shaft  58  is installed into and secured to the chuck. The drill bit  56  is then utilized to drill a hole  84  sized to receive the drop-in anchor  10 . 
     Once the drop-in anchor  10  is inserted into the hole  84 , the plug  26  must be driven into the installed position  40 , which causes the sleeve to expand and engage a wall  86  of the hole  84 . The tool sleeve  70  is then installed over the drill bit  56  by inserting the drill bit  56  into the tool pocket  76  and inserting the protrusions  74  into the slots  72  to secure the tool sleeve  70  over the drill bit  56 . In some embodiments, when the protrusions  74  are engaged in the slots  72 , the bit collar  68  seats on a tool sleeve flange  100 . The plug  26  is driven into the installed position  40  by utilizing the installation tool  54  in this configuration via the tool tip  80 . To drive the plug  26  into the installed position  40 , force is transferred through the drill bit  56  an into the tool sleeve via the collar  70  and tool sleeve flange  100  to the tool tip  80  which acts on the plug  26 . The installation tool  54  disclosed herein requires only installing the installation tool  54  into the chuck a single time during the installation process and allows the hole  84  to be drilled by the drill bit  56  then the drop in anchor  10  installed using the tool sleeve  70  without installing a second tool in the chuck, for a simpler, faster installation process requiring less time for tool changeover between drilling the hole  84  and setting the plug  26 . 
     In some embodiments, as shown in  FIG. 9 , the sleeve  12  includes one or more raised elements, for example, castelations  92  at an exterior of the threaded end  24 .  FIG. 9  illustrates four castelations  92  equally spaced around the threaded end  24 , but it is to be appreciated that other embodiments of the drop-in anchor  10  may utilize other quantities and/or spacing of the castelations  92 . Prior to driving the plug  26  to the installed position, for example, at manufacture of the sleeve  12 , at least a portion of the sleeve  12  including the castelations  92  are coated with a coating having a color that contrasts with a color of the base material of the sleeve  12 . In some embodiments, the coating is a blue paint. It is to be appreciated, however, that the use of blue paint is merely exemplary, and that other colors of paint and/or other types of coatings may be utilized. When the plug  26  is driven to the installed position, bit tip  80  is of a length such that when the plug  26  attains the installed position  40 , a bit shoulder  102  is configured to come into contact with the castelations  92 . As the bit shoulder  102  rotates relative to the sleeve via action of the rotary hammer drill, or the like, while in contact with the castelations  92 , the coating is abraded from the castelations to reveal the sleeve  12  color beneath the coating. Removal of the coating by the bit shoulder  102  serves as a visual indicator to an observer that the drop-in anchor  10  is engaged in the masonry. In other embodiments, the visual indicator may be, for example, deformation of the raised elements by the installation tool or a change in color of a coating applied to the raised elements from contact with a reactionary coating on the setting tool, or a heated element on the setting tool, for example. 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.