Abstract:
The invention provides a rotary tool system and method of operating. In one embodiment, a rotary tool system includes a rotary tool with a rotary motor, an output shaft operatively connected to the motor for transferring rotational force from the motor and a first coupler assembly, a flexible power transmission shaft including a first end portion with a second coupler assembly configured to removably couple with the first coupler assembly, a transfer shaft operatively coupled with the output shaft for receiving rotational force from the output shaft, and a third coupler assembly located at a second end portion of the flexible power transmission shaft and at least one implement, the at least one implement including a fourth coupler assembly configured to removably couple with the second coupler assembly and an input shaft operably connected to the transfer shaft for receiving rotational force from the transfer shaft.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a power hand tool system and more particularly to a motorized power hand tool system. 
       BACKGROUND 
       [0002]    Power tools including battery operated tools are well-known. These tools typically include an electric motor having an output shaft that is coupled to a spindle for holding an implement. The implement may be a drill bit, sanding disc, a de-burring implement, or the like. Electrical power is supplied to the electric motor from a power source. The power source may be provided to the power tool through a cord. Alternatively, the power source may be a battery source such as a Ni-Cad or other rechargeable battery that may be de-coupled from the tool to charge the battery and coupled to the tool to provide power. 
         [0003]    Such power tools may be designed for a variety of special uses. Relatively small rotary hand tools have been marketed for many years for use in carrying out woodworking and metal working tasks by hobbyists as well as commercial artisans. These small rotary hand tools, like the larger power tools, generally have a motor unit with a rotary output shaft that is adapted to be connected to a number of implements such as sanding implements, rotary cutting implements, planing attachments, filing implements, buffing implements and polishing implements. 
         [0004]    The foregoing implements are typically sold separately or as a part of a combined set. In addition to the implements that are used with the rotary tools, various attachments are also available. A common example of an attachment is a cutting guide attachment that is installed onto the rotary tool for use with a cutting implement to guide the cutting path of the rotary tool in a controlled manner relative to a work-piece. Other attachments available include work lights, tool and blade sharpeners, grout removal guides, holders, routing attachments, drilling attachments and shaper tables. 
         [0005]    Many of the implements identified above may be provided with a long flexible shaft that transfers the rotary movement of the output shaft of the rotary tool to the implement. The use of a flexible shaft provides a number of advantages. For example, the implement may be much more maneuverable since the additional bulk of the rotary tool motor need not be manipulated. Additionally, the implement may be fashioned within a housing that is better adapted to the manner in which the implement will be gripped when in use. 
         [0006]    The provision of an implement with a flexible shaft does, however, incur some disadvantages. For example, the implement cannot be directly connected to the rotary tool. Thus, even when the maneuverability of the flexible shaft is not required, the flexible shaft must still be connected. Alternatively, a user can purchase one implement with a flexible shaft and a second instrument without a flexible shaft. This alternative obviously increases both the cost of a tool set as well as the storage area required for the tools set. 
         [0007]    Moreover, the flexible shafts must be accounted for within the storage container. For example, when tool kits are sold, a storage container is frequently provided which is specially formed to both organize the implements and to protect the implements. While providing for one implement with a flexible shaft may not be overly cumbersome within a storage container, the arrangement of a number of different flexible shafts within a single container may become a significant problem when each such shaft is connected to an implement with its own unique storage requirements. 
         [0008]    There is a need to reduce the number of redundant implements that must be maintained without losing the flexibility of using an implement either directly connected to a rotary tool or connected to the rotary tool through a flexible shaft. There is a further need to reduce the number of shafts that are needed to provide for the use of various implements with a flexible shaft. 
       SUMMARY 
       [0009]    Some of the limitations of previously known hand power tools may be overcome by a rotary tool system and method of operating. In one embodiment, a rotary tool system includes a rotary tool with a rotary motor, an output shaft operatively connected to the motor for transferring rotational force from the motor and a first coupler assembly, a flexible power transmission shaft including a first end portion with a second coupler assembly configured to removably couple with the first coupler assembly, a transfer shaft operatively coupled with the output shaft for receiving rotational force from the output shaft, and a third coupler assembly located at a second end portion of the flexible power transmission shaft and at least one implement, the at least one implement including a fourth coupler assembly configured to removably couple with the second coupler assembly and an input shaft operably connected to the transfer shaft for receiving rotational force from the transfer shaft. 
         [0010]    In another embodiment, a universal flexible shaft includes a transfer shaft having a first end portion and a second end portion, a first coupler assembly located at the first end portion for removably coupling with a rotary tool and a second coupler assembly located at the second end portion for removably coupling with a rotary tool implement. 
         [0011]    One method of operating a rotary tool system includes coupling a first end portion of a transfer shaft assembly to a rotary tool, coupling a second end portion of the transfer shaft assembly to a first implement, transferring rotational movement of the rotating tool to the first implement through the transfer shaft assembly, decoupling the first end portion of the transfer shaft assembly from the rotary tool and decoupling the second end portion of the transfer shaft assembly from the first implement. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    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. 
           [0013]      FIG. 1  depicts a plan perspective view of a flexible shaft assembly and a partial cross-sectional view of a rotary tool in a rotary tool system incorporating features of the present invention; 
           [0014]      FIG. 2  depicts a partial cross-sectional view of the male coupler assembly and transfer shaft of the flexible shaft assembly of  FIG. 1 ; 
           [0015]      FIG. 3  depicts a perspective view of a sanding implement held by a user and removably coupled with the flexible shaft assembly of  FIG. 1  in a rotary tool system; 
           [0016]      FIG. 4  depicts a perspective view of the implement of  FIG. 3  directly coupled with the rotary tool of  FIG. 1 ; 
           [0017]      FIG. 5  depicts a side pan view of a random orbit sander implement with a coupler assembly in the form of an overthrow nut mechanism that can be used with the flexible shaft of  FIG. 1  in accordance with features of the present invention; 
           [0018]      FIG. 6  is a side cross-sectional view of the random orbit sander of  FIG. 5  along with a cross-sectional view of an abrasive pad and retaining screw; 
           [0019]      FIG. 7  is a perspective view of the drive shaft of the random orbit sander of  FIG. 5  rotationally supported by two bearings which are spaced apart and an eccentric which provides eccentric motion of the sanding media when the random orbit sander is activated. 
           [0020]      FIG. 8  is a side plan view of an alternative implement in the form of a reciprocating saw with a coupler assembly that can be coupled to a rotary tool either directly or through a flexible shaft assembly in accordance with features of the present invention; 
           [0021]      FIG. 9  depicts a side plan view of the reciprocating saw implement of  FIG. 8  with a portion of the housing removed to reveal a drive shaft assembly which includes a planetary gear set to step down the rotation of the and a cam follower assembly to convert the stepped down rotation to a reciprocating axial motion 
           [0022]      FIG. 10  depicts a side perspective view of an alternative implement in the form of an orbital sander coupled to a flexible shaft assembly in accordance with features of the present invention; 
           [0023]      FIG. 11  depicts a side perspective view of a further alternative implement in the form of an detail sander coupled to a flexible shaft assembly in accordance with features of the present invention; and 
           [0024]      FIG. 12  depicts a is a side plan view of a further alternative implement in the form of an handpiece coupled to a flexible shaft assembly in accordance with features of the present invention. 
       
    
    
     DESCRIPTION 
       [0025]    A power tool system generally designated  100  is shown in  FIG. 1 . In the embodiment of  FIG. 1 , the power tool system  100  includes a rotary tool  102  and a flexible shaft  104 . The rotary tool  102  may be a hand-held, electric tool of the type commercially available under the trademark DREMEL® from Credo Technology Corporation. The rotary tool  102  has an internal electric motor (not shown) which provides a source of rotary power for an axially-oriented output shaft  106 . A male coupler assembly  108  includes a threaded coupler  110  and the end portion of the output shaft  106  which includes a recess  112  and which extends outwardly from the threaded coupler  110 . A collet nut  114  is configured to fit over the output shaft  106 . 
         [0026]    The flexible shaft  104  includes a female coupler assembly  116  which is configured to be coupled with the male coupler assembly  108 . The female coupler assembly  116  includes a threaded coupler  118  and the end portion  122  of a transfer shaft  120  which extends outwardly from the threaded coupler  118 . The transfer shaft  120  extends from the female coupler assembly  116  to a male coupler assembly  126  located at the opposite end of the flexible shaft  104 . The transfer shaft  120  is located within a sheath or casing  128  with a coil support  130  disposed between the transfer shaft  120  and the casing  128  as shown in  FIG. 2 . 
         [0027]    The transfer shaft  120  is preferably made from a flexible metal while the casing  128  is preferably made of durable, inexpensive, thermoformable plastic material such as polyvinylchloride (PVC). Other suitable materials for these components are contemplated. The coil support  130  allows the transfer shaft  120  to rotate within the casing  128 . Coiled, spring-like bend protectors  132  and  134  are located at the end portions of the casing  128  to restrict the ability of the flexible shaft  104  to bend at the end portions of the casing  128 . 
         [0028]    The male coupler assembly  126 , in this embodiment, is configured in the same manner as the male coupler portion  108 . Thus, the male coupler assembly  126  includes an output shaft  136  with a recess  138  and a threaded coupler  140 . A collet  142  is configured to fit over the output shaft  136 . 
         [0029]    Returning to  FIG. 1 , the end portion  122  of the transfer shaft  120  which extends outwardly from the threaded coupler  118  is configured to fit within the recess  112  of the output shaft  106 . Preferably, the recess  112  and the end portion  122  of the transfer shaft  120  are configured such that the end portion  122  of the transfer shaft  120  fits within the recess  112  in a keyed configuration. This may be accomplished, for example, by configuring the end portion  122  of the transfer shaft  120  and the recess  112  to have a common shape (e.g. triangular, rectangular, etc) or by incorporation of a key and slot arrangement. Accordingly, when the female coupler assembly  108  and the male coupler assembly  116  are coupled, the transfer shaft  120  is rotationally engaged with the output shaft  106 . Thus, rotation of the output shaft  106  causes rotation of the transfer shaft  116 . 
         [0030]    The power tool system  100  further includes an implement  144  shown in  FIG. 3  coupled with the flexible shaft  104 . The implement  144  is a contour detail sander implement. The implement  144  includes a housing  146 , a female coupler assembly  148  and a contoured sanding block  150 . The contour sanding block  150  is preferably removably coupled with the implement  144 . Thus, a kit may include a number of different sanding blocks of different shapes and sizes that may be interchangeably coupled with the implement  144 . 
         [0031]    The housing  146  is made from a lightweight material and is shaped to be easily held by a user as shown in  FIG. 3 . The housing sections are preferably made of a plastic or plastic-like material, such as ABS or glass filled nylon. A number of grip portions  152  are provided on the housing to allow a user to more easily grip the implement  144 . The female coupler assembly  148  is configured to mate with the male coupler assembly  126 . Thus, the implement  144  includes a drive shaft (not shown) that couples with the transfer shaft  120  through the recess  138  of the output shaft  136  and a threaded portion (not shown) that mates with the threaded coupler  140 . 
         [0032]    As discussed above, the male coupler assembly  126  is identical to the male coupler assembly  108 . Accordingly, the drive shaft (not shown) of the implement  144  also couples with the output shaft  106  through the recess  112  and the threaded portion (not shown) of the implement  144  mates with the threaded coupler  110  to provide the configuration shown in  FIG. 4 . Thus, the implement  144  may be driven by the output shaft  106  directly or indirectly through the transfer shaft  120 . 
         [0033]    An alternative implement  154  is shown in  FIG. 5 . The implement  154  is a random orbit sander. The implement  154  includes a housing  156 , an overthrow nut mechanism  158 , and a pad retainer  160 . The overthrow nut mechanism  158  includes an outer sleeve  162  and a nut  164  (see  FIG. 6 ) which is provided in two halves. The outer surface of the sleeve  162  is textured with a series of ridges  166  and grooves  168 . 
         [0034]    Referring to  FIG. 6 , an input drive shaft  170  extends within the overthrow nut mechanism  158  and is coupled with a main drive shaft  172 . The main drive shaft  172  is rotationally maintained in alignment within the housing  156  by a bearing  174  and a bearing  176  which are separated by a spacer  178 . 
         [0035]    An eccentric member  180  is connected to the end of the main drive shaft  172 . The eccentric member  180  includes a coupling portion  182 , a mid portion  184  and an end portion  186 . The eccentric member  180  is made of steel. The coupling portion  182  is configured to couple with the main drive shaft  172  via a friction fit. As best seen in  FIG. 7 , the mid portion  184  is not uniformly shaped about the axis  188  of the main drive shaft  172 . The mid portion  184  thus creates an imbalance in the rotation of the main drive shaft  172  about the axis  188 . 
         [0036]    Returning to  FIG. 6 , a bearing  190  is located about the end portion  186 . The centerline of the bearing  190  is offset from the axis  188  of the main drive shaft  172  to provide eccentric motion. The bearing  190  is located within a well  192  of the pad retainer  160 . The pad retainer  160  is configured to hold a pad  194  which is coupled with the pad retainer  160  using a screw  196 . In an alternative embodiment, the pad holder and the pad are a single unit. The pad  194  is typically a soft or spongy material that has some give when pressure is applied to reduce gouging of a work piece. The pad  194  has a smooth lower surface  198  upon which an abrasive material may be mounted. 
         [0037]    In operation, the implement  154  is mounted to either the rotary tool  102  or the flexible shaft  104 . In this example, the implement  154  will be mounted to the flexible shaft  104 . Accordingly, the input drive shaft  170  is inserted through the collet  142  and into the recess  138 . The overthrow nut mechanism  158 , which is a female coupler assembly, is then used to firmly couple the implement  154  with the male coupler assembly  126  of the flexible shaft  104 . As a user rotates the outer sleeve  162  in a first direction, the threads of the nut  164  engage the threads of the threaded coupler  140 . Continued rotation of the sleeve  162  forces the threads of the nut  164  to firmly engage the threads of the threaded coupler  140 , thereby rotationally coupling the input drive shaft  170  with the output shaft  136  as the nut  164  compresses the collet  142  to bind the input drive shaft  170  within the recess  138 . 
         [0038]    The flexible shaft  104  is similarly mounted to the rotary tool  102 . The end portion  122  of the transfer shaft  120  is inserted through the collet  114  and into the recess  112 . The female coupler assembly  116  is then used to firmly couple the flexible shaft  104  with the male coupler assembly  108  of the rotary tool  102 . As a user rotates the threaded coupler  118  in a first direction, the threads of the threaded coupler  118  engage the threads of the threaded coupler  110 . Continued rotation of the threaded coupler  118  forces the threads of the threaded coupler  118  to firmly engage the threads of the threaded coupler  110 , thereby rotationally coupling the transfer shaft  120  with the output shaft  106  as the threaded coupler  118  compresses the collet  114  to bind the end portion  122  of the transfer shaft  120  within the recess  112 . 
         [0039]    Next, the rotary tool  102  is energized. In this embodiment, energization is accomplished using a switch on the rotary tool  102 . In alternative embodiments, energization of the rotary tool may be accomplished using a switch on the implement. Energization of the rotary tool  102  causes the motor (not shown) to rotate which in turn causes the output shaft  106  to rotate. The output shaft  106  is coupled with the transfer shaft  120 , preferably through the use of a keyed configuration, while the transfer shaft  120  is rotatably supported by the coil support  130 . Accordingly, rotation of the output shaft  106  causes the transfer shaft  120  to rotate. 
         [0040]    The transfer shaft  120  is coupled, through the output shaft  136 , with the input drive shaft  170 , preferably through the use of a keyed configuration. Accordingly, rotation of the transfer shaft  120  causes the input drive shaft  170  to rotate. The input drive shaft  170  is coupled with the main drive shaft  172  which is rotatably supported by the bearings  174  and  176 . Thus, rotation of the input drive shaft  170  is transferred to the main drive shaft  172  which in turn causes rotation of the eccentric member  180 . 
         [0041]    The eccentric member  180  is operatively coupled to the pad holder  194  through the bearing  190 . Thus, rotation of the eccentric member  180  provides the orbital motion for the pad holder  194 . The centerline of the bearing  190 , however, is offset from the axis  188  of the main drive shaft  172  and the pad holder  194  is free to rotate about the bearing  190 . Accordingly, movement of the pad holder  194  is not purely orbital. This eccentric movement creates the random orbital movement also known in the trade as dual action. 
         [0042]    The rotational speed of a rotary tool such as the rotary tool  102  can be several thousand rounds per minute. For some applications, the cycling of the particular instrument is preferably much lower. Additionally, some instruments require reciprocating motion. The implement  200  shown in  FIG. 8  is a reciprocating saw that is configured to both convert rotational movement to reciprocating movement and to reduce the frequency of the movement. The implement  200  includes an overthrow nut mechanism  202 , a main housing  204  and a guide foot  206  which supports the implement  200  as a saw blade  208  is used to engage a work piece. 
         [0043]    The implement  200  includes a drive train assembly  210  and a cam follower assembly  212  shown in  FIG. 9 . The drive train assembly  210  includes a drive coupling shaft  214  with an annular outwardly extending flange  216  for limiting axial movement of the coupling shaft  214  relative to a fan blade  218 . The coupling shaft  214  is operably connected to a planetary gear set  220 . The planetary gear set  220  is operably connected to a threaded cylinder  222 . The cam follower assembly  212  includes a knob  224  that is fixedly attached to the blade  208  through a shaft  226 . The knob  224  is entrapped between adjacent threads on the threaded cylinder  222 . 
         [0044]    The planetary gear set  220  reduces the rotational speed between the input and the output of the planetary gear set  220  as more fully detailed in U.S. Patent Publication No. 2005/0252670, published Nov. 17, 2005, the teaching of which is herein incorporated in its entirety by reference. Additionally, the threaded cylinder  222  cooperates with the knob  224  to convert rotational movement to reciprocating movement. More specifically, as the threaded cylinder  222  rotates, the knob  224  is forced to move in an axial direction, thereby creating a reciprocating movement. 
         [0045]    The features identified above may be provided in a number of different combinations for a variety of implements. Referring to  FIG. 10 , an implement  230  is shown coupled with a flexible shaft  232 . The implement  230  is an orbital sander with a female coupler assembly  234 . A pad holder  236  is configured to be coupled with, for example, sand paper. The pad holder  236  may be rotated directed from a shaft (not shown) coupled with and output shaft (not shown) of the flexible shaft  232 . Alternatively, the rotational speed of the pad holder may be reduced by the provision of planetary gears or other mechanisms such as gears for reducing the rotational speed. The female coupler assembly  234  allows the implement  230  to be directly coupled to a rotary tool. 
         [0046]    Referring to  FIG. 11 , a power tool system  240  includes an implement  242  coupled with a rotary tool  244 . The implement  242  is a detail sander with a female coupler assembly  246 . An abrasive component  248  is removably coupled with the implement  242 . Preferably, a number of different abrasive components capable of being removably coupled with the implement  242  and having different sizes, shapes and abrasive qualities are provided in the power tool system  240 . The sanding component  248  is driven in a reciprocating axial motion using a gear system (not shown). The female coupler assembly  246  allows the implement  242  to be directly coupled to a flexible shaft (not shown) that is provided with the power tool system  240 . 
         [0047]      FIG. 12  shows a power tool system  250  which includes an implement  252  coupled with a flexible shaft  254 . The implement  252  is a hand piece with a female coupler assembly  256 . The female coupler assembly  256  allows the implement  252  to be directly coupled to a main rotary tool (not shown) that is provided with the power tool system  250 . While a threaded coupler is preferably incorporated into the female coupler assembly  256 , it is contemplated that other types of fastening connections may be used, including bayonet-type lugs, clips and other repeatable and releasable positive fastening connections. 
         [0048]    A working attachment or bit  258 , may be coupled with an attachment such as, but not restricted to a drill bit, a polishing disk, a grinding wheel, a sanding wheel, a cutting wheel or bit, a wire brush, a saw or other known rotary tool attachment. Preferably, one or more attachments are provided in the power tool system  250 . The implement  252  is designed for enhancing user control of the rotary action of an attachment coupled with the bit  258  for delicate and/or difficult to reach operations. As such, the implement  252  is easier and lighter to hold than the main rotary tool (not shown). 
         [0049]    The implement  252  further includes a lock-out activator  260  which can temporarily lock the bit  258  from rotation. The lock-out activator is configured such that a single hand may be used to hold the implement  250  and to operate the lock-out activator  260 . This operation is helpful when exchanging working attachments. In one embodiment, the lock-out activator  260  is preferably a single pin or button for releasable engagement with a drive shaft coupled with the bit  258 . 
         [0050]    In operation, a user merely depresses the lock-out activator  260  into the implement  250 . The lock-out activator  260  may be outwardly biased by a spring (not shown) so as to hold an actuator out of engagement with the drive shaft or the bit  258 . In one embodiment, the spring is a flat spring formed into a “C”-shape, and defines a gap facing away from the lock-out activator  260 . Thus, depression of the lock-out activator  260  interferes with rotation of the bit  258 . 
         [0051]    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, the 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 the general inventive concept disclosed herein.