Patent Publication Number: US-8122978-B1

Title: Drilling device with undercutting

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
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     REFERENCE TO FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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     REFERENCE TO JOINT RESEARCH AGREEMENTS 
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     REFERENCE TO SEQUENCE LISTING 
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     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to drilling devices, and, particularly, relates to drilling devices for providing increased anchorage, and, in greater particularly, relates to drilling devices for providing a conical anchorage cavity in a bore hole. 
     2. Description of the Prior Art 
     The need for anchoring objects to other surfaces is well known. The material of the substrate may be plastic, wood, bone, concrete, metal, for example, and thus require any anchoring system that is acceptable to many materials. Some materials are brittle and are not able to be threaded by a tap such as concrete and thus the bore hole must be otherwise modified to hold an anchoring system. An anchor bolt may be glued into the bore hole, but this may not be sufficient to hold significant loads under stressful conditions and quickly result in catastrophic failure. The use of anchor bolts with expanding walls is also well known, but again, under stressful conditions such as high vibrations even these may result in loosening of the anchor and eventual failure. A more positive solution to this problem is the modification of the bore hole by undercutting the wall. 
     This problem is addressed in prior patents. For example, one patent discloses an internal cam shaft for rotating a cutting blade into the substrate to produce an undercut portion. Another embodiment shows an expanding balloon held by an internal shaft to push out a pivoted blade. These require modifications to the drill. Another embodiment shows a cantilevered cutting blade which deploys upon a change in the rotation of the drill. There is no external control over the cutting blade itself and further there is no way of removing debris that is created when rotating the drill counter to its normal flute direction which may result in clogging of the cutting blade, breaking of the cutting blade and jamming of the drill in the hole upon an attempted removal. Another patent discloses a drill bit having means for undercutting being extendable fingers running along the shank of the drill. A guide sleeve mounted to the shank operates to extend the fingers when coming into contact with the surface of the workpiece. The number of moving parts would thus expose this drill bit to jamming considering its use in concrete undercutting for example. 
     Several patents disclose undercutting drill bits having fixed lateral cutting blades. One type requires that the drill shank be rocked laterally to cause the enlargement of the hole and another discloses the undercutting head being smaller than the diameter of the actual bore hole. These are specialized undercutting tools without the traditional drill bit for making of the bore hole thus requiring multiple insertions and removals to achieve an anchor cavity. Other patents disclosure undercutting bits having blades that are deployable by means of spring biased shafts. 
     Accordingly, there is an established need for a combined drilling device having cutting blades for undercutting, flutes for removing debris, and a minimum of moving parts that provides these features. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed at a drilling device for making a bore hole and for undercutting a portion of the bore hole for use in an anchoring system. 
     Embodiments of the present invention provide a drilling device for establishing a conically shaped cavity in materials primarily used for anchoring systems. The drilling device is comprised of a solid shank for attachment to a drill, a reverse threaded section, and a cutting head. The cutting head includes a cutting tip, clean out flutes, extendable cutting blades mounted within an internal chamber of cutting head body, and means for extending and returning the cutting blades. The extendable cutting blades project from the cutting head body radially when the reverse threaded section is driven into the internal chamber of the cutting head. The reverse threaded section interacts with the means for extending the cutting blades. This may include a pair of cams that are spring biased outwardly. The cams push against the slanted backsides of the extendable cutting blades for driving them from the cutting head body when the drill device is counter rotated. The extendable blades cut a conical cavity at the distal end of a bore hole made by the cutting tip of the cutting head. After the conical cavity is produced, the drilling device is then clockwise rotated to cause the reverse threaded section being at its most distal position to return to its initial position. Biased springs mounted on the outer part of the body push the cutting blades into the body so that the drilling device can be removed from the bore hole. 
     A feature of the present embodiment is to provide a means undercutting a bore hole. 
     It is another feature of the present invention to provide a drilling device capable of drilling a bore hole as well as undercutting the bore hole. 
     It is a further feature of the present invention to provide a drilling device usable with a conventional drill. 
     It is still a further feature of the present invention to provide a drilling device that operates by changing the direction of rotation of the drilling device. 
     It is yet a further feature of the present invention to provide a drilling device that is able to remove debris irrespective of the direction of rotation of the cutting head and minimizes the number of moving parts. 
     These and other objects, features, and advantages of the present invention will become more readily apparent from the attached drawings and the detailed description of the preferred embodiments, which follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The preferred embodiments of the invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the invention, where like designations denote like elements, and in which: 
         FIG. 1  is a cross sectional view of one embodiment of the present invention of a drilling device with an undercutting means; 
         FIG. 2  is a cross section through a substrate into which a bore hole is placed showing a conical cavity at the bottom on the bore hole; 
         FIG. 3  is a side view of another embodiment of the means for extending the cutting blades of the present invention; 
         FIG. 4  is a side view of the shank having a threaded section for attachment to an anchoring system; 
         FIG. 5  is a cylindrical projection of the side of the body of the cutting head showing the clean out flutes, apertures for cutting blades, and spring biased means for returning the cutting blades of the present invention; and 
         FIGS. 6A and 6B  illustrate by side view the mounting of the cutting blades in the cutting head. 
     
    
    
     Like reference numerals refer to like parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed at a drilling device for providing increased anchorage by providing a conically shaped anchorage cavity in a bore hole. 
     As best shown in  FIG. 1 , generally, the invention is a drilling device  100  for providing a conically shaped cavity  200 ,  FIG. 4 , in a substrate  202  primarily used for anchoring systems, not shown. A base of the conically shaped cavity  204  is located at the distal end of the bore hole  206 . The drilling device  100  is comprised of a solid shank  102  for attachment to a drill, not shown, a reverse threaded section  104 , and a cutting head  106 . The cutting head  106  includes a cutting tip  108 , clean out flutes  502 ,  FIG. 5 , a pair of extendable cutting blades  110  mounted within an internal chamber  112  of a cutting head body  114 , and means  116  for extending the cutting blades  110  and means  118  for returning the cutting blades. The extendable cutting blades  110  project from the cutting head body  114 , shown in outline, radially when the reverse threaded section  104  is driven into the internal chamber  112  of the cutting head  106 . The reverse threaded section  104  interacts with the means  116  for extending the cutting blades  110 . The drilling device  100  rotates about an axis  120 . An arrow  124  shows a clockwise rotation about the axis  120 . It should be understood that drills conventionally turn clockwise when drilling into materials as viewed from the drill shank end, but this may be changed. In the present invention a counter rotation to the drilling is required to properly operate the drilling device  100 . 
     It is well known that drill bits come in a variety of configurations. Technical aspects such as the spiral flute rate, the point angle of the tip, the lip angle of the cutting edges, the length, the diameter, and metal composition may be adjusted. Although the present invention is directed at undercutting for the purpose of an anchoring system, undercutting can be used for other purposes. 
     The shank  102  may be of a predetermined length and made of conventional material used in drill manufacturing. Placed about the shank  102  is an adjustable collar  126  that is used to determine the depth of penetration of the drill tip  108  into the substrate  202 . The proximal end of the shank  102  is attached to the drill and the distal end  128  is fixedly attached to the reverse threaded section  104 . As seen in  FIG. 1 , the reverse threaded section  104  is in its initial position extending from the cutting head  106  a distance  130  measured from a bottom  132  of the cutting head body  114  to the end of the threaded section. The distance  130  would correspond approximately to the distance traveled by the means  116  for extending the cutting blades from the vertical axis  120 . Alternatively, the top of the central support  142  may be of a length to stop in a cavity  115  when the cutting blades  110  are fully extended. In another embodiment, a threaded stop  127  may be mounted to the threaded section  104  and adjusted to control the degree of extending the cutting blades  110  from the device  100 . In the initial position, the cutting blades  110  are not extended from the body  114  and are shown by solid lines. 
     A stop support  134  on the distal end  136  of the reverse threaded section  104  prevents the removal of the reverse threaded section  104  from the cutting head body  114 . A counter clockwise rotation of the reverse threaded section  104  will cause the section  104  to be screwed further into the cutting head  106  for the purpose of extending the cutting blades  110 . Through the application, threads are shown as parallel lines and it is understood that conventional threads are used herein as appropriately noted. 
     As seen in  FIG. 1 , one embodiment of the means  116  for extending the cutting blades  110  is shown. A base  138  is positioned on a top  140  of the stop support  134 . A central support  142  is fixedly attached to the base  138 . A pair of cams  144  are mounted to axles  146  having biasing springs  139  that push the cams  144  into the cutting blades  110 . The cams  144  have grooved faces  147  that ride upon upwardly slanting backsides  148  of the cutting blades  110 . As the reverse threaded section  104  is screwed into the internal chamber  112 , the means  116  is pushed upwards causing the cutting blades  110  to extend from the body  114  as will be shown hereinafter. It should be understood that the internal chamber  112  may lubricated with grease to prevent the entrance of dust and other debris that may jam or clog this device. 
       FIG. 3  illustrates by side view another embodiment of the means  116 . As seen therein, the stop support  134  has a conical cam  300  fixedly mounted thereto. As the reversed threaded section  104  is moved into the internal chamber  112 , sides  302  of cam  300  push against the back sides  148  of the cutting blades  110 . 
       FIG. 4  illustrates a shank  400  of a drilling device  100  wherein the drilling device  100  remains in the bore hole  206  for attaching a support member, not shown, to a threaded section  402  with a portion of the reverse threaded section  104  following. The upper part  404  of the shank  400  is of a smaller diameter than the threaded section  402  so that a threaded adaptor, not shown, of an anchor system can be attached thereto. It thus should be understood that the drilling device of the present invention would remain secured in the bore hole and not removed in one aspect of the present invention. 
       FIG. 5  is a cylindrical projection, a two dimensional view, of a side  500  of the cutting head  106 , a three dimensional shape, of the body  114  showing the clean out flutes  502 , apertures  504  for cutting blades  110 , and spring biased means  506  for returning the cutting blades  110  to inside of the internal chamber  112  of the present invention. The clean out flutes  502  are bi-directional in cleaning of debris from the cutting head  106  in that they are both clockwise and counter clockwise located on the side  500  producing a plurality of channels  508  crossing one another. The extendable cutting blades  110  are pushed out through the apertures  504 . Each aperture  504  has a biased metal finger or biased spring means  506  located at the bottom thereof so that the cutting blades  110  would be urged back into the internal chamber when the reverse threaded section  104  is removed from the internal chamber  112 . The bottom  510  of each finger  506  is weld into the body  114 . 
       FIG. 6A  shows a cutting blade  110  pivotally mounted within the body  114  of the cutting head  106 . The cutting blade  110  has a bottom curved section  602  that is pivotably fitted within a cup  600 . As the cam  144  is pushed up the upward slanting backside  148 , an upper section  604  is pushed outward so that a cutting edge  606  is exposed to the substrate  202 . The cutting edge  606  may be designed for different substrates  202  such as concrete, wood, etc.  FIG. 6B  shows a pin  608  mounted in the bottom  602  of the cutting blade  110  and being positioned within a slotted holder  610 . In either embodiment, the blades  110  may be inserted into the cutting head  106  through the apertures  504  during assembly. 
     In using the present invention to provide the shaped cavity  200  in the bore hole  206 , the drilling device  100  is attached to a drill having a reversible drive. The bore hole  206 ,  FIG. 2 , is cut into the substrate  202  with a clockwise rotation of the drilling device  100 ,  FIG. 1 , until a stop  126  is reached; and at that position, the drill is reversed in rotation to form the shaped cavity  200  in the bore hole  206  with a counter clockwise rotation. If the drilling device  100  is to be removed from the bore hole  206 , the drill is reversed in the rotation, again, to withdraw the cutting blades  110  into the body  114  of the cutting head  106 . 
     Since many modifications, variations, and changes in detail can be made to the described embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents.