Patent Publication Number: US-2012024117-A1

Title: Starter Tool

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This Application claims priority to U.S. Provisional Patent Application No. 61/400,491 filed Jul. 29, 2010, entitled, “Starter Device for Drills and Fasteners”, which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     The present invention generally relates to tools such as power and manual tools, and more particularly, to a starter tool or a tool having a starter device providing an axial impact to a work bit for creating a starter dent in a working surface. 
     Rotatable tools such as screw drivers and drills are frequently used to rotate work bits such as screw driver bits and drill bits. For example, cordless power screw drivers are used to install self tapping screws into a working surface and pistol grip drills are used with drill bits to make holes in a working surface. Depending upon the hardness of the materials on which the tools are used, the work bits tend to drift along the working surface before penetration. Thus, the fastener or hole may be mispositioned. This phenomenon is aggravated when the fastener or drill is driven at an angle other than perpendicular to the working surface. In these situations, the worker may start the fastener or drill perpendicular to the working surface and then tilt the bit once it initially penetrates the working surface. This maneuver slows the operation and has a potential to damage the working surface, the work bit, or the fastener, or to misposition the fastener or hole. Sometimes a tool known as a center punch is used to make a small starter dent in the working surface before the rotatable tool is used. The tip of the fastener or drill bit is positioned in the dent to prevent it from drifting. Center punches may be a simple pointed punch that is struck with a hammer to form the dent in the working surface. Other center punches have a pointed tip and a spring-loaded punching mechanism that impacts the tip when the center punch is pushed against the working surface with a predetermined force to drive the tip into the working surface. Regardless of the type used, center punches slow production due to the need to perform a separate step with a separate tool before the rotatable tool is used. 
     Thus, there is a need for a starter tool or a tool having a starter device that eliminates the need for using a separate tool to create a starter dent in a working surface. 
     SUMMARY 
     In one aspect, the present invention includes a starter tool for use with a rotatable tool. The starter tool comprises a base having a mount adapted to connect to the rotatable tool. The starter tool also includes a chuck adapted to hold a work bit moveably connected to the base for movement with respect to the base between an extended position, in which the chuck is positioned farther from the mount, and a retracted position, in which the chuck is positioned closer to the mount. The chuck is biased toward the extended position and has an anvil surface. In addition, the starter tool comprises a striker mounted on the base for movement with respect to the chuck between a striking position, in which the striker is closer to the anvil surface, and a loaded position, in which the striker is farther from the anvil surface. The striker is biased toward the striking position. Further, the starter tool comprises a release operatively positioned between the striker and the anvil surface of the chuck permitting the striker to move from the loaded position toward the striking position when the chuck reaches the retracted position thereby allowing the striker to provide an impact force on the anvil surface of the chuck to drive the work bit toward a working surface. 
     In another aspect, the present invention includes a tool having a housing. A chuck rotatably mounted on the housing is adapted to hold a work bit for rotating the work bit. Further, the tool comprises an anvil surface mounted on the housing. The tool includes a striker moveably mounted on the housing for movement between a striking position, in which the striker is closer to an anvil surface fixed against axial movement with respect to the housing, and a loaded position in which the striker is farther from the anvil surface. A punch mechanism mounted on the housing operatively positioned between striker and the anvil surface selectively drives the striker toward the anvil surface to drive the work bit toward a working surface. 
     In still another aspect, the present invention includes a starter tool selectively connectible to a rotatable tool. The starter tool comprises a base having a mount adapted to connect to the rotatable tool. The starter tool has a chuck rotatably mounted on the base and adapted to hold a work bit and a punch mechanism operatively connected to the work bit and selectively providing an impact force on the work bit to drive the work bit toward a working surface. 
     In yet another aspect, the present invention includes a starter tool for use with a rotatable tool. The starter tool comprises a base having a mount adapted to connect to the rotatable tool and a chuck adapted to hold a work bit so the work bit moves with respect to the base between an extended position, in which the work bit is positioned farther from the mount, and a retracted position, in which the work bit is positioned closer to the mount. The work bit is biased toward the extended position. The starter tool also includes a striker mounted on the base for movement with respect to the chuck between a striking position, in which the striker is closer to the chuck, and a loaded position, in which the striker is farther from the chuck. The striker is biased toward the striking position. In addition, the starter tool comprises a release operatively positioned between the striker and the work bit permitting the striker to move from the loaded position toward the striking position when the work bit reaches the retracted position thereby allowing the striker to provide an impact force on the work bit to drive the work bit toward a working surface. 
     Other aspects of the present invention will be apparent in view of the following description and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is side elevation of a tool including a starter tool of a first embodiment of the present invention holding a work bit for driving a fastener into a working surface; 
         FIG. 2  is a perspective of the starter tool holding the work bit driving the screw fastener; 
         FIG. 3  is a cross section of the starter tool taken in a plane of line  3 - 3  of  FIG. 2  showing the starter tool in an initial position; 
         FIG. 4  is a cross section similar to  FIG. 3  but showing the starter tool in a partially compressed position; 
         FIG. 5  is a cross section similar to  FIG. 3  but showing the starter tool in a fully compressed or loaded position; 
         FIG. 6  is a cross section similar to  FIG. 3  but showing the starter tool in a striking position; 
         FIG. 7  is a cross section of a starter tool of a second embodiment of the present invention; 
         FIG. 8  is a perspective of a tool of a third embodiment having an internal starter device for creating a starter dent; and 
         FIG. 9  is a perspective of a tool of a third embodiment in partial cross section. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the drawings. 
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Referring to  FIG. 1 , a combined tool incorporating a first embodiment of the present invention is designated in its entirety by the reference number  20 . The combined tool  20  includes a rotatable tool, generally designated by  22 , and a starter tool, generally designated by  24 . Although the rotatable tool may be of other types without departing from the scope of the present invention, in one embodiment the rotatable tool  22  is a battery powered, pistol grip, portable electric drill. In other embodiments the tool  22  may have other forms, such as a manual drill or screw driver, an AC powered portable drill, a power screw driver, a hand grinder, a lathe, or a drill press. The rotatable tool  22  includes a chuck  26  for gripping the starter tool  24  and a trigger  28  for energizing the rotatable tool to rotate the chuck about its central axis thereby rotating a work bit  30 , such as a screw driver bit or a drill bit, to penetrate a working surface S. As the features of the rotatable tool  22  and the work bit  30  are well known to those skilled in the art, they will not be described in further detail. 
     As shown in  FIG. 2 , the starter tool  24  includes a body or base, generally designated by  40 , having a shank or mount  42  at one end for mounting the starter tool in the chuck  26  of the rotatable tool. The starter tool  24  has a chuck, generally designated by  44 , opposite the mount  42  for holding the work bit  30 . As further illustrated in  FIG. 3 , the base  40  of the starter tool  24  is formed from three annular components, a chuck holder  46 , a striker holder  48 , and the mount  42 . In the embodiment illustrated in  FIG. 3 , the base components  46 ,  48 ,  42  are fastened together using screw fasteners  50 ,  52 . An inner surface  60  of the chuck holder  46  includes a shoulder  62  and a retainer groove  64  for receiving an annular retainer  66  such as a split ring retainer. An outer surface  70  of the chuck  44  is sized and shaped to be received in the inner surface  60  of the chuck holder. The chuck  44  includes a flange  72  that engages the shoulder  62  and the retainer  66  to limit sliding movement of the chuck relative to the base  22 . The chuck  44  moves in the base  40  between an extended position (as shown in  FIG. 3 ), in which the chuck is positioned farther from the mount  42 , and a retracted position (as shown in  FIG. 6 ), in which the chuck is positioned closer to the mount. When in the extended position the flange  70  of the chuck  44  engages the retainer  66  and when in the retracted position the flange is positioned adjacent the shoulder  62 . The chuck  44  includes a stem  74  extending toward the mount  42  from an anvil surface  76 . The chuck  44  has an opening  78  for receiving the work bit  30 . A magnet  80  provided in the opening  78  holds the bit in the opening. Although the chuck  44  in the illustrated embodiment is a magnetic chuck, the chuck may be of other types, such as a ball detent chuck or a mechanical collet chuck, without departing from the scope of the present invention. The chuck  44  is biased toward the extended position by a return spring  82  that pushes against the striker holder  48  component of the base  40 . Although the illustrated return spring  82  is a coil compression spring, those skilled in the art will appreciate that the starter tool  24  may be reconfigured to use other types of springs. 
     As further illustrated in  FIG. 3 , a hammer or striker  90  is mounted in an inner surface  92  of the striker holder  48 . The striker  90  includes a hole  94  sized and shaped for receiving the stem  74  of the chuck  44 . A flange  96  provided on the striker  90  engages a shoulder  98  formed in the inner surface  92  of the striker holder  48  for limiting sliding movement of the striker relative to the base  22 . The striker  90  moves with respect to the base  22  between a striking position (as shown in  FIG. 3 ), in which the striker is closer to the anvil surface  76  of the chuck  44  and a loaded position (as shown in  FIG. 5 ), in which the striker is closer to the mount  42 . The striker  90  is biased toward the striking position by a main or punch spring  100  that pushes against a plug or set screw  102  fastened inside the mount  42 . Although the illustrated punch spring  100  is a coil compression spring, those skilled in the art will appreciate that the starter tool  24  may be reconfigured to use other types of springs. The cantilever spring  104  is fastened to a planer surface of the striker  90  with a screw fastener  106  for engaging a release, generally designated by  110 , operatively and physically positioned between the striker and the anvil surface  76  of the chuck  44 . 
     The release  110  includes a body  112  having an opening  114  and a sloped surface  116  that aligns the body opening with the chuck stem  74  and the striker hole  94  as the body travels from a partially compressed position as shown in  FIG. 4  to a fully compressed or loaded position as shown in  FIG. 5 . Once the release  110  is in the loaded position as shown in  FIG. 5 , the release opening  114  is aligned with the striker hole  94  and the chuck stem  74 . When the release opening  114 , the striker hole  94 , and the chuck stem  74  are aligned, the striker  90  is free to accelerate toward the chuck  44  under force generated by the punch spring  100 , driving the release body  112  to impact the anvil surface  76  of the chuck to drive the work bit  30  toward the working surface S causing a starter dent to be formed in the working surface. As will be appreciated by those skilled in the art, the tool  24  components move from the position shown in  FIG. 3 , through the positions shown in  FIG. 4  and  FIG. 5 , to the position shown in  FIG. 6  by pushing the mount  42  toward the work bit  30 , thereby compressing the return spring  82  and punch spring  110 . Once the release impacts the chuck  44 , pressure on the mount  42  may be released, allowing the return spring  82  and punch spring  110  to expand to return the tool  24  to the initial position shown in  FIG. 3 . As the tool returns to the initial position, the cantilever spring  104  moves the release body  112  so the body opening  114  is out of alignment with the chuck stem  74  and the striker hole  94 . The materials and processes used to manufacture the starter tool  24  are well within the skill of those in the art and will not be described in further detail. 
     To use the combined tool  20 , an operator pushes the tool toward the working surface S. As the tool  20  is pushed toward the surface S, the punch mechanism in the tool described above, drives the work bit  30  toward the working surface creating a starter dent. While maintaining pressure on the tool  20 , the operator activates the tool to rotate the work bit  30 . 
     Referring to  FIG. 7 , a starter tool of a second embodiment of the present invention is designated in its entirety by the reference number  200 . The tool  200  includes a base  202  having a mount  204 . A chuck  206  is fastened to the base  202  opposite the mount  204  so the chuck is stationary with respect to the mount. The chuck  206  comprises a ball detent  208  that is biased toward a central opening  210  of the chuck sized and shaped for holding a work bit  212 . The base  202  and chuck  206  form an interior  220  sized for holding a striker  222 . The interior  220  includes a shoulder  224  for limiting sliding movement of the striker  222  relative to the base  202 . The striker  222  moves with respect to the base  202  between a striking position, in which the striker touches the shoulder  224  and a loaded position, in which the striker is closer to the mount  204  and spaced from the shoulder. The striker  222  is biased toward the striking position by a main or punch spring  230  that pushes against a face  232  of the base  202  adjacent the mount  204 . Although the illustrated punch spring  230  is a coil compression spring, those skilled in the art will appreciate that the starter tool  200  may be reconfigured to use other types of springs. The striker  222  also includes a central hole  232  facing the work bit  212 . 
     As further shown in  FIG. 7 , a trigger or release, generally designated by  240 , is mounted in the interior  220  immediately adjacent the work bit  212 . The trigger  240  includes a head  242 , a shaft  244  extending from the head, and a stem  246  extending from the shaft. The trigger  240  further includes a tapered section  248  between the shaft  244  and the stem  246 . The stem  246  is sized to be received in the striker hole  232  and the shaft  244  is sized to be received in a necked portion  250  of the interior  220 . As shown in  FIG. 7 , the necked portion  250  includes a tapered face  252  for leading the stem  246  and shaft  248  into the necked portion. The trigger  240  is biased toward the work bit  212  by a return spring  254  that engages the tapered face  252  and the head  242  of the trigger. Further, the spring  254  and/or the trigger head  242  are shaped to tilt the trigger  240  so the stem  246  is forced out of alignment with the striker hole  232 . 
     When the work bit  212  is pushed against the working surface S, the ball detent  208  releases the work bit so it slides in the chuck opening  210  toward the mount  204 . The work bit  212  pushes the trigger  240  against the force of the return spring  254  toward the striker  222 . Because the stem  246  and the striker hole  232  are not aligned, the trigger  240  forces the striker  222  toward the mount  204  against the force of the punch spring  230 . When the tapered portion of the trigger  240  meets the tapered face  252 , the stem  246  is centered in the neck portion  250  so the stem is aligned with the striker hole  232 . As the stem  246  enters the striker hole  232 , the striker  222  is accelerated forward until an end of the striker hole hits an end of the striker stem. This impact drives the work bit  212  toward the working surface S forming a starter dent in the working surface. The operator can continue to push the work bit  212  against the working surface S until the striker  222  bottoms out against the face  232  of the base  202 . Thus, substantial force may be applied to the work bit  212  by the operator when the tool is activated to rotate the work bit. As the other operation and features of the second embodiment will be apparent to those skilled in the art, they will not be described in further detail. As will apparent to those skilled in the art, the springs, releases, triggers, and strikers of the starter tools described above constitute punch mechanisms for driving the work bits toward the working surfaces. 
     Referring to  FIG. 8 , a tool of a third embodiment of the present invention is designated in its entirety by the reference number  300 . The tool  300  includes a pistol grip housing  302  having a chuck  304  rotatable mounted on the housing. Although the chuck may be of other types without departing from the scope of the present invention, in one embodiment, the chuck  304  is a mechanical collet chuck. The chuck  304  is selectively rotated by a motor  310  as shown in  FIG. 9  to rotate a work bit  312  held in the chuck. A trigger  314  provided on the housing  302  energizes the motor  310  to rotate the chuck  304 . As further illustrated in  FIG. 9 , a hardened anvil surface  320  is mounted on the housing  302  at a forward end of a tubular cavity  322 . A striker  324  is slidably received in the cavity  322  so it can move between an striking position in which the striker engages the anvil surface  320  and a loaded position in which the striker is spaced from the anvil surface. A spring  326  engages the striker  324  to bias the striker toward the loaded position shown in  FIG. 9 . A coil  330  of conductive wire surrounds the striker  324 . A button  332  on the housing  302  is provided to energize the coil  330  causing an electromagnetic field to drive the striker  324  forward toward the anvil surface  320 . When the striker  324  impacts the anvil surface  320 , the work bit  312  is forced toward the working surface forming a starter dent. As those skilled in the art will appreciate, the coil  326  and striker  324  act as a solenoid. It should be noted that the striker  324  need not be axially aligned with the work bit  312  to impart an axial force on the bit. As will apparent to those skilled in the art, the solenoid and anvil surface described above constitute a punch mechanism for driving the work bit toward the working surface. 
     As will be appreciated by those skilled in the art, the embodiments of the invention described above permit a starter dent to be formed with one tool, during a single operation, using one hand. Further, the embodiments of the invention permit less expensive non-self-starting-tip sheet metal screws to be used in certain applications where they were not effective in the past. 
     Having described the invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. 
     When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
     As various changes could be made in the above constructions, products, and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.