Abstract:
Discloses is an anchor bolt including a stud. The anchor bolt further includes a wedge in operable communication with the stud. The anchor bolt still further includes a heat treated then cold worked sleeve disposed about the stud and in operable communication with the wedge.

Description:
BACKGROUND 
       [0001]    An anchor bolt is typically used to attach objects or structures to a base material. The general components of an anchor bolt are a stud, a wedge and a sleeve portion. In use, a hole is drilled or otherwise formed in the base material that has a diameter only slightly larger than that of the wedge and the sleeve of the anchor bolt. This allows passage of the wedge and the sleeve of the anchor bolt into the hole. Upon expansion of the sleeve, however, the material thickness of the sleeve is interposed between the wedge and the base material. This effectively increases the diameter of the wedge by roughly twice the thickness of the sleeve. Since the hole diameter in the base material does not change appreciably due to the expansion input, the anchor bolt becomes substantially permanently anchored in the base material. 
         [0002]    Both function and longevity of such anchor bolts in large part rely on the properties of the sleeve portion. More specifically the material must be durable enough and durable enough to provide suitable anchoring capability and reasonable life. Heretofore, the only material deemed acceptable by the art has been stainless steel material. While this material is quite appropriate for the task its cost factor is difficult to absorb. Since economic considerations are important in nearly all industries, the art is always receptive to alternative configurations. 
       SUMMARY OF THE INVENTION 
       [0003]    According to one aspect of the invention, an anchor bolt includes a stud and a wedge in operable communication with the stud. The anchor bolt further includes a heat treated then cold worked sleeve disposed about the stud and in operable communication with the wedge. 
         [0004]    According to another aspect of the invention, an anchor bolt includes a stud and a wedge in operable communication with the stud. The anchor bolt further includes a low carbon steel sleeve disposed about the stud and in operable communication with the wedge. 
         [0005]    According to yet another aspect of the invention, a method for manufacturing an anchor bolt sleeve includes heat treating a steel blank, and cold working the steel blank into an anchor bolt sleeve subsequent to the heat treating, the anchor bolt sleeve being expandably receptive to a wedge of an anchor bolt. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0006]    The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
           [0007]      FIG. 1  depicts a side view of an anchor bolt according to an embodiment of the present invention; 
           [0008]      FIG. 2  depicts a perspective view of a steel blank disclosed herein; and 
           [0009]      FIG. 3  depicts a perspective view of a fully formed sleeve disclosed herein. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    A detailed description of the hereinafter described embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
         [0011]    Referring to  FIGS. 1-3 , an embodiment of an anchor bolt  10  disclosed herein is shown. The anchor bolt  10  includes, a wedge  12 , a sleeve  14  and a stud  16 . The wedge  12  is threadably engaged with the stud  16  such that rotation of the stud  16  relative to the wedge  12  causes the wedge  12  to move axially along the stud  16 . This axial movement of the wedge  12  causes the wedge  12  to also move axially relative to the sleeve  14  thereby causing radial expansion of the sleeve  14 . The radial expansion of the sleeve  14  results in a frictional engagement between the sleeve  14  and walls  17  of a hole  18  in a work piece  20  to which the anchor bolt  10  is being attached. It should be understood that the anchor bolt  10  is not limited to this configuration, but may include any configuration having a wedge and a sleeve. As disclosed herein, prior to its formation, the sleeve  14  is a steel blank  22  that is first hardened with at least one heat treatment technique. Thereafter, a cold work process is used to further harden the sleeve  14  and finish forming the sleeve  14  into its final configuration. In the embodiments disclosed herein the cold work process includes rolling the steel blank  22  into a hollow cylindrical shape  23  as shown in  FIG. 3 . The hollow cylindrical shape  23  shows two adjacent sides  24  of the steel blank  22  joined along an axial seam  26  in the finished sleeve  14 . 
         [0012]    The steel blank  22  is made of one or more of a low carbon steel and a high strength, low alloy (HSLA) steel. A low carbon steel has less than about 0.25% by weight carbon whereas a HSLA steel has elements such as copper, vanadium, nickel, and molybdenum in combined concentrations as high as about 10% by weight. Thus, the steel blank  22  is composed of a material that is cold workable after being hardened. 
         [0013]    Hardening of the steel blank  22  is accomplished with at least one heat treatment process. In one embodiment, the steel blank  22  is quenched and tempered. Quenching and tempering results in at least one of a stronger and harder steel blank  22 , or any combination thereof that is favorable in durability, vibration resistance, load capacity, etc. In one embodiment, the heat treatment results in a steel blank  22  having a Rockwell C hardness of less than 35. This allows the steel blank  22  to be more easily formed by a cold working process. 
         [0014]    Forming the steel blank  22  into hollow cylindrical shape  23  of the sleeve  14  includes a cold working process, such as, rolling, drawing, pressing, spinning, extruding, for example, or any other process that produces a desirable sleeve shape. In addition to forming the steel blank  22  into hollow cylindrical shape  23 , the cold working process also increases a strength and hardness of the sleeve  14  in the process. The cold working process may result in a steel blank having a hardness greater than 35 on the Rockwell C hardness scale. Furthermore, by cold working to the final hollow cylindrical shape  23  after heat treating, embodiments disclosed herein prevent the seam  26  from opening up during heat treating as would likely occur had the heat treating been performed after the forming to the final hollow cylindrical shape  23 . 
         [0015]    Sizing of the sleeve  14  into the final hollow cylindrical shape  23  is important to the proper operation of the anchor bolt  10 . The sleeve  14  is sized to be expandably receptive to the wedge  12  during setting of the anchor bolt  10 . In the embodiment shown, the sleeve  14  has an inner diameter  27  that is greater than an outer diameter  28  of a shank  29  of the stud  16 . As such, the shank  29  is free to rotate within the sleeve  14  before and during setting. 
         [0016]    Exapandability of the sleeve  14  about the wedge  12  is facilitated by formation of at least one longitudinal opening  30 , illustrated herein as a slot, in a wall  31  of the sleeve  14 . The slot(s)  30  can be formed in the sleeve  14  at the formation of the blank  22  or during the formation of the final cylindrical shape  23 . The slot(s)  30  allow a portion  32  of the sleeve  14  to be radially deflected without the necessity of stretching the material of the sleeve  14  or opening up the seam  26 . In other embodiments, the sleeve may be configured for being stretched. Additional features may also be formed in the sleeve  14 . For example, gripping projections  33  may be introduced on the sleeve  14  either during or prior to formation of the sleeve  14 . The gripping projections  33  can increase friction between the base material and the sleeve  14  during setting of the anchor bolt  10 . The gripping projections  33  are shown oriented in a latitudinal direction but may also be a longitudinal projection or may have a non-axial shape. 
         [0017]    While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.