Abstract:
The present invention is a method and device for a hand power tool which includes a housing, a storage compartment within the housing, a wrench for manipulating a collet bit attachment structure, a portion of the wrench sized to fit within the storage compartment, a first spring extending into the storage cavity and positioned to bias the portion of the wrench against an inner wall of the storage compartment and a protuberance positioned on the housing, such that when the portion of the wrench is partially within the cavity, the protuberance causes a first misalignment between the longitudinal axis of the storage compartment and the longitudinal axis of the wrench and when the portion of the wrench is fully within the cavity, the protuberance does not cause a misalignment between the longitudinal axis of the storage compartment and the longitudinal axis of the wrench as large as the first misalignment.

Description:
FIELD OF THE INVENTION 
   The present invention relates to hand tools and more particularly to a power hand tool. 
   BACKGROUND 
   Hand held rotary tools are widely used by many people including professionals, craftspeople, homeowners, and artists. These rotary tools typically include an outer housing designed to be easily held within a human hand. The housing retains an electric motor which is operable to drive a rotatable chuck of the rotary tool. The widespread use of hand held rotary tools is a result, in part, of the wide variety of accessories that may be used with the tools. The accessories include cut-off wheels, polishing wheels, grinding wheels, sanding discs, routing bits and other cutting bits. 
   The accessories may be removably coupled with the rotary tool using a collet. By way of example, a prior art hand-held rotary power or cutting tool  20  is shown generally in  FIGS. 1-3A . The rotary cutting tool  10  includes a motor housing  12  to which a detachable handle  14  is attached. An electric motor (not shown) is enclosed within the motor housing  12 . The motor receives electrical power through an electrical cord  16  (only a portion of which is shown in  FIG. 1 ). The electric motor is turned on and off by a power on/off switch  18  mounted on the motor housing  12 . 
   An end of the motor shaft extends from one end of the motor housing  12 . Attached to the end of the motor shaft is a collet bit attachment structure  20  for removably securing an accessory, such as those identified above, to the motor shaft. The collet bit attachment structure  20  includes a collet nut  22  and a collet  24  centered axially within a central aperture of the collet nut  22 . The collet nut  22  is mounted on a threaded end of the motor shaft. To secure a bit to the motor shaft, a shank of the bit is inserted into a central aperture  26  of the collet  24 . The collet nut  22  is then tightened, first by hand and then with a wrench  28 , until the bit is held securely. To remove the bit from the motor shaft, the collet nut  22  is loosened, using the wrench  28 , until the bit can be removed easily from the central aperture  26  of the collet  24 . 
   The use of a wrench to tighten a collet bit attachment structure allows for accessories to be securely coupled with a tool. So as to ensure the proper wrench is available to a user, some devices provide a storage compartment within the rotary tool. For example, the wrench  28  for tightening the collet nut  24  may be stored in the compartment  30  formed inside the handle  14 . The size of the compartment  30  is such that the wrench  28  is frictionally held therein to prevent it from sliding out during operation of the tool  10 . 
   While the system of  FIGS. 1-3A  provides a convenient manner of storing a wrench that is used with a collet bit attachment structure, some users prefer a storage system that provides a more obvious indication that the wrench is firmly held within the storage compartment. Typically, a positive indication of proper insertion may be provided by a configuration that suddenly reduces the resistance to insertion of a component into a tool once the component is properly inserted into the tool. The sudden lessening of resistance provides positive feedback to the user that the component has been inserted into the tool. 
   Positive feedback may be provided in various ways. By way of example,  FIG. 3A  shows a housing  34  that includes a compartment  36 . A coil spring  38  is positioned partially within the compartment  36 . Accordingly, as the wrench  28  is inserted into the compartment  36 , the wrench  28  compresses the coil spring  38 . As a cavity  40  in the wrench  28  is positioned adjacent to the coil spring  38 , the coil spring expands into the cavity  40 . Positive feedback is thus provided to the user as the user feels the expansion of the coil spring  38  into the cavity  40 . 
   While providing advantages, the use of a coil spring  38  tends to generate scratches on the wrench  28 . Additionally, positioning the coil spring  28  within the housing  34  requires modification to both halves of the housing  34 . Moreover, because the coil spring  38  is positioned within both halves of the housing  34 , assembly of the device requires the coil spring  38  to be positioned within one half of the housing  34 , with a portion of the coil spring  38  extending out of the half of the housing  34 . Thus, the spring coil  38  may become misaligned during assembly of the housing  34 . 
   While the provision of positive feedback is desired by some users, the manner in which a tool is configured in order to provide such feedback is also important to the users. For example, if the resistance is completely removed, the component is likely to move and rattle within the tool. Many users, however, interpret excessive movement and rattling of the components of a tool as an indicator of an inferior product, even if the movement and noise has no bearing upon the quality of the tool. 
   Moreover, other components in rotary tools require some amount of movement in order to provide the requisite operability. By way of example, the on/off switch is generally moved between a first position wherein power is applied to the internal motor and a second position wherein power is not applied to the internal power. Thus, some movement must be allowed. The allowance of movement is accomplished by designing the various components to be mismatched in size. While the mismatch in size allows for operation of the component, the resultant looseness may cause undesired noise as the tool is operated leading to the belief that the tool is an inferior device. 
   What is needed is a power hand tool which provides a positive indication that a tool such as a wrench is securely held therein. It would be beneficial to provide this benefit while minimizing the number of components needed to manufacture the tool. 
   What is further needed is a power hand tool which reduces noise and looseness of components. It would be beneficial to provide this benefit while minimizing the number of different components needed to manufacture the tool. 
   SUMMARY 
   The present invention is a method and device for a hand power tool system. In one embodiment, the device includes a housing, a storage compartment within the housing, a wrench for manipulating a collet bit attachment structure, a portion of the wrench sized to fit within the storage compartment, a first spring extending into the storage cavity and positioned to bias the portion of the wrench against an inner wall of the storage compartment and a protuberance positioned on the housing, such that when the portion of the wrench is partially within the cavity, the protuberance causes a first misalignment between the longitudinal axis of the storage compartment and the longitudinal axis of the wrench and when the portion of the wrench is fully within the cavity, the protuberance does not cause a misalignment between the longitudinal axis of the storage compartment and the longitudinal axis of the wrench as large as the first misalignment. 
   In one embodiment, a hand power tool system includes a housing, a storage compartment within the housing, a wrench for manipulating a collet bit attachment structure, a portion of the wrench sized to fit within the storage compartment; a first spring extending into the storage cavity and positioned to bias the portion of the wrench against an inner wall of the storage compartment, a switch movably attached to the housing, a second spring structurally identical to the first spring and positioned within the housing to bias the switch away from the housing and a protuberance positioned on the housing such that when the portion of the wrench is partially within the cavity, the protuberance causes a first misalignment between the longitudinal axis of the storage compartment and the longitudinal axis of the wrench. 
   One method of manipulating a rotary tool system includes inserting a first portion of a wrench within a storage compartment defined in the housing of a rotary tool, compressing a first spring extending into the storage compartment with the first portion of the wrench, contacting a lower portion of the storage compartment with the first portion of the wrench while the spring is compressed, contacting a protuberance located on the housing outside of the storage compartment with a second portion of the wrench, contacting a first upper portion of the storage compartment with a third portion of the wrench, deforming the opening of the compartment, moving the second portion of the wrench toward the opening of the compartment while the opening is deformed and biasing the first portion of the wrench against a second upper portion of the storage compartment with the first spring. 
   These and other advantages and features of the present invention may be discerned from reviewing the accompanying drawings and the detailed description of the preferred embodiment of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention may take form in various system and method components and arrangement of system and method components. The drawings are only for purposes of illustrating exemplary embodiments and are not to be construed as limiting the invention. 
       FIG. 1  shows an exploded perspective view of a prior art rotary tool with a detached handle; 
       FIG. 2  shows bottom plan view of the collet bit attachment structure of the rotary tool of  FIG. 1 ; 
       FIG. 3A  shows a partial cross sectional view of a wrench for use with the collet bit attachment structure of  FIG. 2  stored within a compartment of the removable handle of the rotary tool of  FIG. 1 ; 
       FIG. 3B  shows a partial cross sectional view of a wrench for use with the collet bit attachment structure of  FIG. 2  stored within an alternative compartment wherein a coil spring is provided to securely hold the wrench within the compartment; 
       FIG. 4  shows a side perspective view of a hand rotary tool system including a wrench for use with the collet bit attachment structure of a rotary tool stored within a compartment of the rotary tool in accordance with principles of the invention; 
       FIG. 5  shows a side plan view of the inside of a clam shell portion of the housing of the rotary tool of the hand rotary tool system of  FIG. 4 ; 
       FIG. 6  shows a partial side plan view of the inside of the clam shell portion of  FIG. 5  with a storage compartment spring installed in accordance with principles of the invention; 
       FIG. 7  shows a side perspective view of the storage compartment spring of  FIG. 6 ; 
       FIG. 8  shows a top plan view of the storage compartment spring of  FIG. 6 ; 
       FIG. 9  shows a top perspective view of the wrench of  FIG. 4 ; 
       FIG. 10  shows a partial side plan view of the inside of the clam shell portion of  FIG. 5  with a storage compartment spring installed with a side cross sectional view of the wrench of  FIG. 1  being positioned within the opening of the storage compartment in accordance with principles of the invention; 
       FIG. 11  shows a partial side plan view of the inside of the clam shell portion of  FIG. 5  with a side cross sectional view of the wrench of  FIG. 1  being used to compress the storage compartment spring in accordance with principles of the invention; 
       FIG. 12  shows a partial side plan view of the inside of the clam shell portion of  FIG. 5  with a side cross sectional view of the wrench of  FIG. 1  positioned such that the storage compartment spring is depressed and the wrench is wedged between a protuberance and a lower portion of the storage compartment on one side and an upper portion of the storage compartment on the other side; 
       FIG. 13  shows a partial side plan view of the inside of the clam shell portion of  FIG. 5  with a side cross sectional view of the wrench of  FIG. 1  positioned within the storage compartment with the storage compartment spring biasing the wrench against an upper portion of the storage compartment; 
       FIG. 14  shows a partial side plan view of the inside of the clam shell portion of  FIG. 5  with a switch spring installed and biasing the power on/off switch of the rotary tool of  FIG. 1  in a direction outwardly from the housing; 
       FIG. 15  shows a side perspective view of the switch spring of  FIG. 14  which is structurally identical to the storage compartment spring of  FIG. 6  in accordance with principles of the invention; 
       FIG. 16  shows a top plan view of the storage compartment spring of  FIG. 15 ; 
       FIG. 17  shows a bottom perspective view of the power on/off switch of the rotary tool of  FIG. 1 ; 
       FIG. 18  shows a top perspective view of the power on/off switch of the rotary tool of  FIG. 1 ; 
       FIG. 19  shows a schematic view of the end portion of the switch spring of  FIG. 14  biasing the power on/off switch of the rotary tool of  FIG. 1  in a direction outwardly from the housing; 
       FIG. 20  shows a schematic view of the elbow portion of the switch spring of  FIG. 14  biasing the power on/off switch of the rotary tool of  FIG. 1  in a direction outwardly from the housing when the power on/off switch has been moved upwardly from the position shown in  FIG. 19 ; and 
       FIG. 21  shows a schematic view of the arm portion of the switch spring of  FIG. 14  biasing the power on/off switch of the rotary tool of  FIG. 1  in a direction outwardly from the housing when the power on/off switch has been moved upwardly from the position shown in  FIG. 20 . 
   

   DESCRIPTION 
   Referring to  FIG. 4 , a rotary tool system  100  includes a housing  102  and a power supply cord  104 . An electric motor (not shown) is located within the housing  102  and is turned on and off by a power on/off switch  106  mounted on the housing  102 . A collet nut  108  is part of a collet bit attachment structure attached to a shaft (not shown) which extends from the motor out of the housing  102 . The rotary tool system  100  further includes a wrench  110  which is sized to be used with the collet nut  108 . 
   The housing  102  includes, in this embodiment, two clamshell portions  112  and  114 . The clamshell portion  112  is, for the most part, a mirror image of the clamshell portion  114 . Accordingly, the internal aspects of the housing  102  are described herein with reference to clamshell  114 . The clamshell portion  114  shown in  FIG. 5  defines, along with the clamshell portion  112 , a power port  116  through which the power supply cord  104  extends to provide power to the electric motor, a shaft port  118  through which the shaft (not shown) extends and a switch port  120  through which the power on/off switch  106  extends. 
   The housing  102  further includes a storage compartment  122 . The storage compartment  122  includes an upper wall  124  and a lower wall  126 . The lower wall  126  terminates at a spring port  128  located near to the opening  130  of the storage compartment  122 . A protuberance  132  is located on the clamshell portion  114  near the opening  130  to the storage compartment  122 . The housing  102 , which may be molded from any acceptable material, is configured such that the shape of the opening  130  may be flexibly deformed while the protuberance  132  is relatively rigid. 
   The spring port  128  is sized to allow a storage spring  134  to extend into the storage compartment  122  as shown in  FIG. 6 . The storage spring  134 , which is more clearly shown in  FIGS. 7 and 8 , includes a base portion  136 , an arm portion  138  and an end portion  140 . The base portion  136  includes a pivot portion  142  and a stop portion  144 . The arm portion  138  in this embodiment includes a flat and wide contact area  146  on the upper surface of the storage spring  134 . The arm portion  138  is connected to the end portion  140  through a curved elbow  148 . When the storage spring  134  is positioned within the housing  102 , the lower surface of the pivot portion  142  abuts a pivot  150  while the upper surface of the stop portion  144  abuts a stop member  152  as shown in  FIG. 6 . 
   The wrench  110 , shown in  FIG. 9 , includes a head  154  with two tines  156  and  158  and a shaft  160  with a tapered end portion  162 . The shaft  160  is configured to fit within the storage compartment  122 . Insertion of the shaft  160  into the storage compartment  122  begins by maneuvering the tapered end portion  162  over the protuberance  132  and through the opening  130  of the storage compartment  122  as shown in  FIG. 10 . 
   As the wrench  110  is inserted further within the storage compartment  122 , the position of the wrench  110  is constrained by the upper and lower surface of the opening  130 . The size of the opening  130  thus forces the axis of the wrench  110  into closer alignment with the axis of the storage compartment  122  as the wrench  110  is further inserted into the storage compartment  122 . Accordingly, the wrench  110  is rotated in the direction of the arrow  164  from the position shown in  FIG. 10  to the position shown in  FIG. 11 . 
   The continued insertion of the wrench  10  into the storage compartment  122  in the direction of the arrow  166  brings the tapered end portion  162  of the shaft  160  into contact with the storage spring  134 . As the tapered end portion  162  is forced against the contact area  146  of the storage spring  134 , the storage spring  134  is rotated in the direction of the arrow  168 . The base portion  136  of the storage spring  134 , however, is trapped between the pivot  150  and the stop member  152 . Accordingly, the storage spring  134  is compressed and more of the pivot portion  142  of the storage spring  134  is brought into contact with the pivot  150 . 
   The storage spring  134  is configured such that the contact area  146  provides a wide surface for contact with the shaft  160 . Thus, the potential for damage to the wrench  110  caused by the contact between the shaft  160  and the contact area  146  is reduced. Additionally, the storage spring  134  is smooth along the length of the arm portion  138 , over the elbow  148  and along the length of the end portion  140 . Accordingly, the potential that the storage spring  134  could scratch the lower surface of the wrench  110  is further reduced. 
   Compression of the storage spring  134  continues as the wrench  110  is further inserted into the storage compartment  122 . Additionally, as more of the shaft  160  is inserted into the storage compartment  122 , the axis of the wrench  110  continues to be driven toward alignment with the axis of the storage compartment  122 . Specifically, the upper surface of the opening  130  contacts the upper surface of the shaft  160  and the storage spring  134  contacts the lower surface of the shaft  160 , thereby causing rotation of the wrench  110  into alignment with the storage compartment  122 . 
   As the tapered end portion  162  is inserted beyond the spring port  128 , it comes into contact with the lower wall  126 . Thus, the lower wall  126  contacts the lower surface of the shaft  160 , thereby continuing rotation of the wrench  110  into alignment with the storage compartment  122  as the wrench  110  is further inserted within the storage compartment  122 . The alignment of the wrench  110  with the storage compartment  122  continues until the wrench  110  is in the position shown in  FIG. 12 . In  FIG. 12 , the wrench  110  has been rotated such that the shaft  160  is firmly engaged with 1) the lower wall  126  at the tapered end portion  162 , 2) the upper surface of the opening  130  at the upper surface of the shaft  160  and 3) the protuberance  132  at the lower surface of the shaft  160 . Thus, further movement of the wrench  110  into the storage compartment  122  cannot occur without deformation at one of the contact points. Moreover, further rotation of the wrench toward the axis of the storage compartment  122  cannot occur. 
   As noted above, the opening  130  is configured to be flexibly deformable. Thus, pressure applied to the wrench  110  causes the wrench  110  to deform the opening  130  of the storage compartment  122 , thereby allowing the wrench  110  to be further inserted into the storage compartment  122 . 
   As the insertion continues, the opening between the two tines  156  and  158  is positioned over the protuberance  132 . Thus, the protuberance  132  no longer restrains the wrench  110  from moving into alignment with the storage compartment  122 . Accordingly, the deformed opening  130  springs back to its original non-deformed condition forcing the wrench  110  in the direction of the arrow  170  to the position shown in  FIG. 13 . This provides positive feedback to a user that the wrench  110  is positioned within the storage compartment  122 . 
   Additionally, the storage spring  134  continues to bias the shaft  160  of the wrench  110  in an upward direction. Since the head  154  of the wrench  110  is no longer supported by the protuberance  132 , the continued bias from the storage spring  134  on the shaft  160  causes the wrench  110  to be firmly held between the storage spring  134  and the upper wall  124  of the storage compartment  122 . 
   In this embodiment, the rotary tool system  100  is further configured to use a spring which is structurally identical to the storage spring  134  in other areas of the rotary tool system. Referring to  FIG. 14 , the switch spring  180  is identical to the storage spring  134 . As shown in  FIGS. 15 and 16 , the switch spring  180  includes a base portion  182 , an arm portion  184  and an end portion  186 . The base portion  182  includes a pivot portion  188  and a stop portion  190 . The arm portion  184  in this embodiment includes a flat and wide contact area  192  on the upper surface of the switch spring  180 . The arm portion  184  is connected to the end portion  186  through a curved elbow  194 . When the storage spring  134  is positioned within the housing  102 , the lower surface of the pivot portion  182  abuts a pivot  196  while the upper surface of the stop portion  190  abuts a corner of the wall defining the storage compartment  122  which functions as a stop member as shown in  FIG. 14 . 
   The switch spring  180  is positioned to bias the on/off switch  106  which is shown in more detail in  FIGS. 17 and 18 . The power on/off switch  106  in this embodiment includes a number of ribs such as ribs  200 ,  202  and  204  along with two actuators  206  and  208 . Two flanges  210  and  212  extend outwardly from the on/off switch  106 . 
   When assembled, the actuators  206  and  208  extend through the switch port  120  to control the position of a mechanical switch to alternately provide power to and remove power from the motor (not shown) as the on/off switch  106  is moved along guides (not shown) in the housing  102  which are sized slightly larger than the flanges  210  and  212 . 
   The ribs  200 ,  202  and  204  are provided to increase the strength of the on/off switch  106  while reducing the amount of materials used in the production of the on/off switch  106 . In this embodiment, the tip portion  214  of the rib  200 , which is beveled as shown most clearly in  FIG. 19 , is biased by the switch spring  180 . 
   In operation, the on/off switch  106  is in the “off” position shown in  FIG. 19  which places the rotary tool system  100  in a de-energized state. To energize the rotary tool system  100 , an operator pushes the on/off switch  106  upwardly in the direction of the arrow  216 . This forces the tip portion  214  more firmly against the end portion  186  of the switch spring  180 . Because the stop portion  190  abuts the wall of the storage compartment  122  on the upper surface of the switch spring  180  while the pivot portion  188  contacts the pivot  196  on the lower surface of the switch spring  180 , the base portion  182  of the switch spring  180  is anchored. Accordingly, the force of the tip portion  214  against the end portion  186  causes the switch spring  180  to compress and the arm portion  184  and the end portion  186  rotate about the pivot  196  in the direction of the arrow  218 . The rib  202  is positioned within the switch  106  to limit movement of the arm portion  184  toward the switch  106  as pressure is applied to the end portion  186  thereby ensuring that the switch spring  180  rotates in the direction of the arrow  218 . 
   The rotation of the arm portion  184  and the end portion  186  about the pivot  196  in the direction of the arrow  218  continues until the on/off switch  106  is in the position shown in  FIG. 20 . In  FIG. 20 , the tip portion  214  has moved along the switch spring  180  to a position over the elbow  194 . Accordingly, continued movement of the on/off switch in the direction of the arrow  216  moves the tip portion  214  of the on/off switch  106  away from the contact point between the tip portion  214  and the switch spring  180 . Thus, as the on/off switch  106  continues to move upwardly over the arm portion  184 , the arm portion  184  and the end portion  186  reverse the direction of rotation and begin to rotate in the direction of the arrow  220  to the “on” position shown in  FIG. 21 . 
   Thus, the switch spring  180  maintains contact with the on/off switch  106  throughout the travel path of the on/off switch  106 . Moreover, the switch spring  180  maintains a continuous bias against the on/off switch  106  in the direction of the arrow  220  over the entire travel path of the on/off switch  106 . Thus, once the tip portion  214  passes the elbow  194  when moving in the direction of the arrow  216 , the switch spring  180  provides assistance to the operator in moving the on/off switch  106  completely into the “on” position. Conversely, when the tip portion  214  passes the elbow  194  when moving in the direction opposite of the arrow  216 , the switch spring  180  provides assistance to the operator in moving the on/off switch  106  completely into the “off” position. 
   The structure of the switch spring  180  thus allows for the end portion  186  to be used as a contact area in addition to the contact area  192  so as to vary the effect on the on/off switch  106 . If desired, a more consistent biasing may be provided by configuring the switch spring  180  to contact the on/off switch  106  along just the arm portion  184  and the elbow  194 , in a manner similar to the configuration of the storage spring  134 , or just along the end portion  186  and the elbow  194 . 
   Moreover, the angle between the end portion  184  and the arm portion  184  may be varied to provide different effects. In one embodiment, the end portion and the arm portion are formed on with the same radius of curvature and the same origin to provide a more gradual change. Such a configuration, for example, may be used with a structure such as the rib  202  to provide for smooth operation over the travel path of a component. If desired, the spring can be configured with a curve that does not significantly assist in moving the switch to a different position while applying a biasing force against the switch. 
   Additionally, the spring may be used to provide increased resistance to movement and/or additional indication of proper seating of a wrench. For example, the hole in the wrench  110  shown in  FIG. 9  may be configured such that the hole is positioned over the elbow  148  of the storage spring  134  when the wrench  110  is inserted into the storage compartment  122 , and sized such that at least a portion of the elbow  148  is allowed to extend upwardly into the hole. Accordingly, when the hole is positioned over the elbow  148 , the storage spring  122  partially decompresses as the elbow moves into the hole. This provides an additional indication that the wrench  110  is properly positioned within the storage compartment  122 . Additionally, removal of the wrench  110  requires the storage spring  134  to be compressed prior to removal of the wrench  110 , providing additional resistance to the removal of the wrench  110 . Alternatively, a spring could be configured to move into another surface feature of the wrench such as a recess to provide a similar result. 
   While the present invention has been illustrated by the description of exemplary processes and system components, and while the various processes and components have been described in considerable detail, applicant does not intend to restrict or in any limit the scope of the appended claims to such detail. Additional advantages and modifications will also readily appear to those skilled in the art. The invention in its broadest aspects is therefore not limited to the specific details, implementations, or illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.