Patent Publication Number: US-6668941-B2

Title: Screw holding and driving device

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to screw holding and driving tools and, more particularly, to a screw holding and driving tool for use with a powered drill. 
     Various screw holding and driving devices have been proposed for aiding in the insertion and retention of a tip of a tool such as a screwdriver or power drill in position and contact with a screw for and while the screw is being driven into a work piece. One type of device for a screwdriver is a hollow, generally cylindrically shaped centering sleeve that extends beyond the tip and blade of the screwdriver to surround part or all of the screw head. The centering sleeve must normally be made at least partially retractable so as not to interfere with proper screw engagement if the screw head is to be driven flush with the surface. 
     Another such holding and driving device is disclosed in U.S. Pat. No. 4,736,658 issued to Jore on Apr. 12, 1988. The Jore screw holding and driving device has a shank secured at one end to a handle and a screw driving bit at another end of the shank. A sleeve is positioned in surrounding relation to the shank and sized to slidably rotate around the shank and to slidably move in a longitudinal direction with respect to the shank. The sleeve is used to hold a screw head during the driving operation. Retaining means are provided to hold the sleeve on the shank. 
     The above devices keep the tip of the screwdriver onto the screw head, but are not applicable to power drills. With respect to power drills, it has been recognized that a drill operator cannot see the position of the screw nor easily determine the angle, speed, or depth that a screw is driven into a work piece. Therefore, various devices have been proposed for power drills. These devices, however, make it typically difficult to load a screw into the device. As well, it is generally difficult to see easily set to a driving depth for the screw into the work piece. 
     What is needed therefore is a screw holding and screwing device for a power drill, which overcomes one or more drawbacks of the previously designed devices. 
     For example, what is needed is a screw holding and screwing device for a power drill that allows the easy loading of screws therein. 
     Moreover, for example, what is needed is a screw holding and screwing device for a power drill that provides an adjustable depth setting for driving the screw into a work piece. 
     Further, for example, what is needed is a screw holding and screwing device for a power drill that provides on tool storage for screw bits. 
     SUMMARY OF THE INVENTION 
     The present invention is a screw holding and driving device for a power drill. The screw holding and driving device includes a body, a guide tube, and a drive assembly. The body, guide tube, and drive assembly cooperate to receive and retain a screw for driving the screw into a work piece. 
     In one form, the screw holding and driving device also includes a depth adjuster for setting a driving depth of the screw. 
     In another form, the screw holding and driving device provides for top loading of a screw directly into the drive tube. 
     In yet another form, the screw holding and driving device includes an on-tool storage caddie for screw bits. 
     The present screw holding and driving device guides a screw into a work piece and helps prevent cam out. Screws are easily loaded and visible to the operator once loaded so that the operator can see depth, angle, and speed that the screw is being driven. The spring-loaded nature of the guide tube provides automatic extension of the guide tube to the loading position. The free spinning body with the integral bit holder helps prevent drywall tearing. Off center mass allows for the screw loading slot to always present itself upwards. The present device also extends the reach of the power tool by reaching areas of limited access and provides a convenient storage for additional bits. 
     As well, the present invention has a magnetic bit to hold the screw in a correct starting position and helps prevent the screw from falling out of the guide tube before the screw is driven. The body and guide tube cooperate to provide a releasable lock position when the guide tube is in a retracted position. The depth adjustment allows for countersinking or raised screw heads. 
     In an alternative embodiment, a simplified construction is utilized in which the spring-loaded guide tube provides an annular bore to receive a portion of the spring within the guide tube. In this embodiment, the apparatus is end-loaded, rather than side-loaded. The function of this embodiment is otherwise the same as for the other embodiments. 
     It is therefore an object of the present invention to provide a new and useful screw holding and driving tool. 
     It is another object of the present invention to provide an improved screw holding and driving tool. 
    
    
     Other objects and benefits of the present invention can be discerned from the following description and accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings wherein: 
     FIG. 1 is a front perspective view of an embodiment of a screw holding and driving tool in accordance with the present principles that is operatively attached to an exemplary powered drill; 
     FIG. 2 is an exploded view of the screw holding and driving tool of FIG. 1; 
     FIG. 3 is a front perspective view of another embodiment of a screw holding and driving tool in accordance with the present principles; 
     FIG. 4 is a top plan view of the screw holding and driving tool of FIG. 3; 
     FIG. 5 is a front plan view of the screw holding and driving tool of FIG. 4 taken along line  5 — 5  thereof; 
     FIG. 6 is a cross-sectional side view of the screw holding and driving tool of FIG. 4 taken along line  6 — 6  thereof; 
     FIG. 7 is a top plan view of a guide tube for the present screw holding and driving tool; 
     FIG. 8 is a side plan view of the guide tube of FIG. 7; 
     FIG. 9 is an end view of the guide tube of FIG. 8 taken along line  9 — 9  thereof; 
     FIG. 10 is an end view of the guide tube of FIG. 8 taken along line  10 — 10  thereof; 
     FIG. 11 is a side view of a body for the present screw holding and driving tool of FIG. 3; 
     FIG. 12 is a cross-sectional view of the body of FIG. 11 taken along line  12 — 12  thereof; 
     FIG. 13 is an end view of the body of FIG. 11 taken along line  13 — 13  thereof; 
     FIG. 14 is an end view of the body of FIG. 11 taken along line  14 — 14  thereof; 
     FIG. 15 is a perspective view of a sleeve for the present screw holding and driving tool of FIG. 3; 
     FIG. 16 is a side view of the sleeve of FIG. 15 showing internal threads and a cavity in phantom; 
     FIG. 17 is an end view of the sleeve of FIG. 16 taken along line  17 — 17  thereof; 
     FIG. 18 is an end view of the sleeve of FIG. 16 taken along line  18 — 18  thereof; 
     FIG. 19 is a side cross-sectional view of the sleeve of FIG. 15; 
     FIG. 20 is a perspective view of a bearing cap for the present screw holding and driving tool; 
     FIG. 21 is an end view of the bearing cap of FIG. 20 taken along line  21 — 21  thereof; 
     FIG. 22 is a side view of the bearing cap of FIG. 21 taken along line  22 — 22  thereof; 
     FIG. 23 is a side view of the bearing cap of FIG. 21 taken along line  23 — 23  thereof; 
     FIG. 24 is a side view of a shaft for the present screw holding and driving tool; 
     FIG. 25 is an end view of the shaft of FIG. 24 taken along line  25 — 25  thereof; 
     FIG. 26 is and end view of the shaft of FIG. 24 taken along line  26 — 26  thereof; 
     FIG. 27 is a side view of a spring for the present screw holding and driving tool; 
     FIG. 28 is an end view of the spring of FIG. 27 taken along line  28 — 28  thereof; 
     FIG. 29 is a diagram showing insertion of a screw into the present screw holding and driving tool; and 
     FIG. 30 is a diagram showing the screw being held by the screw holding and driving tool of FIG.  29 . 
     FIG. 31 is a side view of a screw holding and driving tool in accordance with a further embodiment of the invention. 
     FIG. 32 is a side partial cut-away view of a guide tube for use with the tool depicted in FIG.  31 . 
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set forth herein illustrates a preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     Referring now to FIG. 1, there is shown a portable power drill  40  having a screw receiving, holding and/or driving device  42  (hereinafter screw device) created in accordance with principles presented herein attached to the power drill  40  in a conventional manner. The screw device  42  is configured to be removably received in a chuck portion  44  of the power drill  40  and operably attached thereto. The screw device  42  includes a body  46 , a spring loaded screw receiving, guide and/or holding tube or sleeve  48  (hereinafter guide tube), and a drive assembly (see FIG.  2 ). 
     The guide tube  48  is preferably normally in an extended position relative to the body  46  as is depicted in FIG.  1 . The extended position of the guide tube  48  allows receipt of a screw (not shown) within the guide tube  48  that is to be screwed into a work piece (not shown) [hereinafter synonymously the screwing operation]. The screw is received through a configured opening in the side wall of the guide tube  48 . The screw is thereafter retained in the guide tube  48  adjacent a screw bit for the screwing operation. The guide tube  48  is adapted to axially retract towards the body  46  and substantially coaxial therewith during the screwing operation. The guide tube  48  is normally biased into the extended position and thus has a tendency to return to the extended position after release of axial pressure therefrom (i.e. the end of the screwing operation). 
     Referring to FIG. 2, components of the screw device  42  are shown in an exploded view. Essentially, the screw device  42  is composed of the body  46 , the guide tube  48 , and the drive assembly  90 . The drive assembly  90  is adapted to receive a screw bit  74  and is essentially composed of a drive shaft assembly  70  and a spring  68 . The body  46  slidably retains the guide tube  48  within a bore or hole  50  of the body  46  that extends the length of the body  46 . The bore  48  is essentially annular to accommodate the essentially annular guide tube  48 . The body  46  is thus essentially cylindrical and includes a draft or taper  52  at one end thereof. Among other reasons, the draft  52  aids in the molding process, especially when pertaining to plastics. 
     The body  46  further includes a bit stow, rack or storage device  54  radially depending from an end thereof and preferably formed integral therewith. A screw bit  56  is shown retained by the bit stow  54  in FIG.  2 . The bit stow  54  may hold any number of insert (e.g. screw, drill) bits. In the present embodiment, the bit stow  54  holds three (3) insert bits using a friction retention configuration. 
     The guide tube  48  essentially defines a cylinder and thus has a central bore or hole  58  extending the axial length thereof. The guide tube  48  is preferably formed of a relatively clear material. A drive shaft assembly  70  cooperates with the guide tube  48  and the body  46  to form the screw device  42 . The guide tube  48  includes a screw opening  60  in a side wall thereof that is configured to receive a head and shank portion of a screw (not shown). The screw opening is configured to define a profile of a screw to accommodate the screw head and shank portions thereof. The guide tube  48  further includes a collar  62  on one end thereof. The collar  62  is a radially outwardly extending annular flange or ridge that defines first and second stop and/or seating surfaces. In particular, the collar  62  defines two essentially annular, axial seating surfaces; namely, a front seating surface  64  and a rear seating surface  66 . The front seating surface  64  is adapted to contact a stop surface within the bore  50  (e.g. depending from a sidewall) of the body  46  to axially limit the extended position of the guide tube  48  relative to the body  46  when the guide tube  48  is biased into the extended position. The rear seating surface  66  is adapted to contact or abut an end  80  of a spring  68  of the drive shaft assembly  90 . An anti-rotator feature is configured between the guide tube  48  and the body  46  as explained below, in order to maintain the guide tube  48  rotationally fixed relative to the body  46 . 
     The drive shaft assembly  70  includes a drive shaft  71 , a bearing cap  78 , and a bit retainer  72 . The bearing cap  78  is disposed on the drive shaft  71  proximate an end that is formed into a shank  76 . The bearing cap  78  includes a radially outwardly extending annular flange or ridge that defines first and second stop and/or seating surfaces. Particularly, the bearing cap  78  defines first and second annular, axial stop surfaces; namely a front stop surface  84  and a rear stop surface  86 . The front stop surface  84  is adapted to abut an end  82  of the spring  68 , while the drive shaft  71  is within the spring  68 . The bearing cap  78  of the drive shaft  70  is rotatably retained on the drive shaft  71  with the aid of at least a snap ring  88  and associated annular groove (not shown) in the surface of the drive shaft  71 . 
     The drive shaft  70  extends through the opening  58  of the guide tube  48  and the opening  50  of the body  46 . The bearing cap  78  is received inside the opening  50  of the body  46  and is retained within the body  46  by fasteners (not shown) such as screws that extend from the exterior of the body  46 . In this manner, the drive shaft  70  is free to rotate within the guide tube  48  and body  46  since the bearing cap  78  of the drive shaft  70  is fixed relative to the body  46 . The guide tube  48  is also preferably rotatably fixed within the body  46 . The drive shaft  70  includes the bit retainer  72  in an end thereof opposite the shank  76 . The bit retainer  72  includes an internal magnet  75  at an end of an opening  73 . The opening  73  is configured to receive an end of a complementarily configured screw bit  74 , typically of a hexagonal configuration. The screw bit  74  is susceptible to magnetism such that the magnet  75  within the drive shaft  71  at the end of the opening  73  magnetically retains the screw bit  74 . The shank  76  is configured/adapted to be received in the chuck portion  44  of the power drill  40 . The power drill  40  thus rotates the drive shaft  71  for the screwing operation. 
     The spring  68  normally axially biases the guide tube  48  into the extended position from the body  46  as depicted in FIG. 1. A screw is inserted into the guide tube  48  from the screw opening  60  with the head of the screw towards the power drill  40  and the tip away from the power drill  40 . The screw head is magnetically held onto the screw bit  74 , such that the screw is axially retained within the guide tube  48 . The end of the guide tube  48  is positioned over a suitable place for the screw, after which the power drill  40  is caused to rotate the drive shaft  70  and thus the screw via the screw bit  74 . The screw bit  74  is chosen to be received on the particular type of screw being used. Axial pressure against the power drill  40  during the screwing operation pushes the guide tube  48  against a work piece. This axial pressure compresses the spring  68  between the rear seating surface  66  of the stop collar  62  of the guide tube  48  and the front stop surface  84  of the stop collar  78  of the drive shaft  71  within the body  46  which allows the axial movement of the guide tube  48  towards the power drill  40 . Axial movement of the guide tube  48  towards the power drill  40  ceases when the end of the body  46  abuts the work surface. The screwing operation is then complete. 
     Referring now to FIG. 3, there is shown another embodiment of a screw device generally designated  100 . The screw device  100  is substantially the same as the screw device  42  in form, function, and operation with the exception of a depth adjuster  102 . The depth adjuster  102  of the screw device  100  allows adjustment of the driving depth of the screw. It should be appreciated that the various features explained below with reference to the screw device  100 , apart from the depth adjuster  102 , apply to the screw device  42  and vice versa unless otherwise indicated. 
     The screw device  100  includes a body  104 , a spring loaded screw receiving, guide and/or holding tube or sleeve  106  (hereinafter guide tube), a drive assembly  108 , and a depth adjuster  102 . An insert bit stow  112  depends from the body  104  and is preferably formed integral therewith. A bit  114  is shown in the screw device  104 . 
     Referring now to FIG. 4, there is shown a top plan view of the screw device  100 . The guide tube  106  is shown in the extended position relative to the body  104 . A shank  110  of the drive assembly  108  extends from a bearing cap  128  that is attached to an end of the body  104 . The shank  110  is adapted to be received in a chuck of a drill. Preferably, the shank  110  is configured to be received in all ½″ and ⅜″ drills. An adjustment sleeve  130  of the depth adjuster  102  is disposed at an end of the body  104  with the guide tube  106  extending from the body  104 /adjustment sleeve  130 . 
     With additional reference to FIGS. 7-10, the guide tube  106  will be described in greater detail. The guide tube  106  is preferably made of a plastic such as a polycarbonate. As well, the guide tube  106  is preferably transparent in order to discern a screw that has been placed therein, and particularly, a color tinted transparent grade of polycarbonate. It should be appreciated, however, that other suitable materials of various light properties may be used. The guide tube  106  includes a screw opening  120  disposed in the cylindrical sidewall defining the guide tube  106 . The screw opening  120  is in communication with a cylindrical bore or opening  122  in the guide tube  106 . The screw opening  120  is configured to receive a screw by having a shank opening portion  126  and a head opening portion  124 . The shank opening portion  126  allows a shank of a screw to pass therethrough, while the head opening portion  124  allows a head of the screw to pass therethrough. In other words, the screw opening  120  follows the profile of the screw or fastener to restrict the orientation of the fastener for insertion. 
     Each end of the guide tube  106  includes a respective draft or taper  134 ,  136 . The guide tube  106  further includes an annular collar  138  proximate one end thereof. The annular collar  138  extends radially outwardly from the guide tube  106  and defines first and second axial seating surfaces. Particularly, the collar  138  defines a forward seating surface  140  and a rearward seating surface  142 . As best seen in FIG. 6, the forward seating surface  140  abuts a radially inward stop surface  146  of the body  104  to prevent the guide tube  106  from exiting the body  104  and to limit the forward travel of the guide tube  106  relative to the body  104  when the guide tube  106  is in the extended position. 
     The guide tube  106  further includes an anti-rotation member  144  depending from the collar  138 . The anti-rotation member  144  cooperates with a groove  150  (having groove sections  152  and  154 ) on an inside surface of the body  104  (see FIG. 12) to rotationally fix the guide tube  106  within the body  104 . 
     Referring now to FIGS. 11-14, the body  104  will be described in greater detail. The body  104  is preferably made of a plastic such as an ABS (medium to high impact grade) plastic molded as one, integral piece. The body  104  is essentially cylindrical and thus defines an internal bore or hole  156  that extends the longitudinal length of the body  104 . The groove  150  formed by a first groove portion  152  and a second groove portion  154  extend longitudinally along an inside surface of the body  104 . The groove  150  cooperates with the anti-rotation member  144  such that the anti-rotation member  144  is retained in the groove portions  152  and  154  during extension and retraction of the guide tube  106  within the body  104 . 
     The body  104  further has a radially inward annular flange  146  formed on an inside surface of the body  104  at one end thereof. Threads  138  are formed on an outside surface of the body  104  at the same end thereof as part of the depth adjuster  102  to cooperate with the adjustment sleeve  130 . Two radially projecting stops  160  and  162  are formed on the outside surface of the body  104  proximate the threads  138  and act as detent position holders for the sleeve  130  when the sleeve  130  is rotated. This aids in maintaining the sleeve  130  in its rotated position and preventing inadvertent rotation. 
     The body  104  also includes the bit stow  112  that is preferably integrally formed with the body  104  and which is configured to hold insert bits. The particular bit stow  112  includes two bays  168  and  170  to each retain an insert bit such as the bits  116  and  118  seen in FIGS. 5 and 6. The body  104  also includes two notches  164  and  166  on one end thereof that are adapted to receive hooks or prongs of the bearing cap  128 . 
     Referring to FIGS. 20-22 the bearing cap  128  is shown. The bearing cap  128  is preferably made of a plastic, such as an acetyl homopolymer (an unfilled general purpose grade). The bearing cap  128  includes a bore or aperture  172  that is configured to rotatably retain the drive shaft  132  of the drive assembly  108 . The bearing cap  128  further includes a first annular or disc portion  174  that defines a first seating surface  178  for abutting against the end of the body  104 , and an inner portion  184  defining a second seating portion  177  that abuts an end of the spring  182  (see FIG.  6 ). The bearing cap  128  also includes two hooked prongs  178  and  180  that are adapted to be received in the notches  164  and  166  of the body  104  to aid in retaining the bearing cap  128  onto the body  104 . The bearing cap  128  is rotationally fixed relative to the body  104  to allow the drive shaft  132  and the shank  110  to rotate. 
     Referring to FIGS. 24-26 the drive shaft  132  of the drive assembly  108  is shown. The drive shaft  132  is preferably made of aluminum but other suitable materials may be used. The drive shaft  132  includes a bit retaining bore  186  in one end thereof that is configured to receive an end of a bit. The bore  186  is shown as hexagonal which is typical of bits. Of course, the bore  186  may be shaped differently. A magnet  188  is disposed at an axial end of the bore  186  for magnetically retaining a bit inserted into the bore  186 . 
     The drive shaft  132  includes the shank  110  on the end opposite the bit bore  186 . The shank  110  is preferably made of steel and is press fit into a shank bore  190 . The shank  110  is configured to be received in a chuck of a drill for rotating the shank  110  which rotates the drive shaft  132  which rotates a bit in the bit bore  186 . The drive shaft  132  further includes a first annular groove on an outside surface thereof proximate the shank  110  for receiving a snap ring or clip  196  (see FIGS. 4 and 6) to aid in retaining the bearing cap  128  onto the body  104 . The drive shaft  132  further includes a second annular groove  194  on an outside surface thereof axially spaced from the first groove  192  that also aids in retaining the bearing cap  128  onto the body  104 . 
     Referring to FIGS. 27 and 28, the spring  182  as part of the drive assembly  108  is shown. The spring  182  may be any type of spring suitable for the present application. Preferably, however, the spring  182  is made of plated music wire, 0.032″ having a free length of 5.0″ and an outside diameter of 0.470″. As well, the spring  182  preferably has closed ends and sixteen (16) total coils. 
     Referring to FIGS. 15-19, the adjustment sleeve or sleeve  130  forming part of the adjuster  102  is shown. The sleeve  130  is preferably made of a plastic such as an ABS (medium to high impact grade) and is formed in a generally cylindrical shape thereby defining a central bore  204 . The sleeve  130  includes a curved or tapered front or nose  202  having internal threads  206 . The sleeve  130  is sized to be received over the body  104  with the threads  206  cooperating with the threads  158  of the body such that the sleeve  130  is rotatable on the body  104 . The sleeve  130  also includes an annular stop surface  146  at the beginning of the threads  206  adjacent the taper  202 . 
     The sleeve  130  is received on the body  104  as best seen in FIG.  6 . In particular, the sleeve  130  extends over the body  104 . The threads  206  of the sleeve  130  are engaged with the threads  158  of the body  104  such that the sleeve  130  is axially movable (i.e. by rotation), both axially forward and rearward, along and relative to the body  104 . The seating surface  140  of the collar  138  of the guide tube  106  abuts the stop  146  of the body  104  when the guide tube  106  is in the extended position. 
     When axial rearward (i.e. towards the shank  110 ) pressure is exerted against the guide tube  106  during the screwing operation, the guide tube  106  axially compresses the spring  182  allowing the guide tube  106  to retract into the body  104 . As the guide tube  106  retracts, the screw is driven into the work piece. Eventually, the guide tube  106  retracts at least flush with a front surface  198  (defined by the taper  202 ) of the sleeve  130 . The front surface  198  of the sleeve  130  relative to the bit  114  is axially adjustable such that more or less (to none) of the bit  114  may be exposed from the front surface  198  when the guide tube  106  retracts and the front surface  198  reaches the work piece. Axially rotating the sleeve  130  in a clockwise direction axially moves the sleeve  130  and thus the front surface  198  axially rearward, exposing more of the bit  114 . Since more of bit  114  is exposed, the head of the screw will be driven deeper into the work piece (relative to the surface of the work piece) before the device bottoms out (i.e. the front surface  198  contacts the work piece). Axially rotating the sleeve  130  in a counterclockwise direction axially moves the sleeve  130  and thus the front surface  198  axially forward, exposing less of the bit  114 . Since less (to none or less) of the bit is exposed, the front surface reaches the surface of the work piece before the screw head, thereby having the screw head raised from the surface of the work piece. The axial rotation (adjustment) is infinitely variable within the range of rotation. Such range of rotation is restricted by the sleeve/body configuration (e.g. the threads  158  on the body  104 ). After the driving operation, axially forward pressure against the guide tube  106  is released, allowing the compressed spring  182  to uncompress and axially force the guide tube  106  into the normal, extended position. 
     It should be appreciated that the guide tube  48  includes a spring-loaded automatic return to the extended position that is also the screw loading position. This allows an operator to load screws and drive them using only one hand. The depth adjustment sleeve allows the operator to set the desired screw depth by simply turning the threaded sleeve. Adjustment depth is various depending on configuration, but a typical adjustment range is around {fraction (3/16)}″. 
     The loading of a screw into the present screw device will now be described with additional reference to FIGS. 29 and 30. Initially, it should be appreciated that the body  104  in FIGS. 29 and 30 has had the sleeve  130  removed for clarity. A screw  300  is place into the screw opening  120  in the guide tube  106 , with the shank of the screw into the shank opening portion  126  first, and thereafter the head of the screw into the head opening portion  124 . The head of the screw is magnetically attracted to the bit  114 , where it is retained thereon. The screw opening  120  is always presented facing up (top) since the drive assembly is free spinning relative to the guide tube  106  and the body  104  and has an off center mass. The screw device is now ready for the screwing operation. 
     An alternative embodiment of the invention is depicted in FIGS. 31 and 32. This embodiment implements end-loading of the screw, rather than the side loading capability found in the prior embodiments. In particular, a screw holding and driving device  250  includes a cylindrical body  255 , and a guide tube  260  slidably disposed within a bore  256  of the body  255 . A drive assembly  265  is disposed within the body  255  and guide tube  260 , in a manner similar to the drive assembly  108  described above. As with the assembly  108 , the drive assembly  265  of the present embodiment can include a drive shaft assembly  267  held in position relative to the body  255  while allowing the assembly to rotate. Preferably, a snap ring  269  is engaged about the shaft assembly  267  to hold the assembly in place. 
     In the embodiment depicted in FIGS. 31 and 32, the drive assembly  265  further includes a spring  270 . Like the spring  68  in the prior embodiment, the spring  270  is arranged between the body  255  and the guide tube  260  to force the guide tube to a normally extended position, as shown in FIG.  31 . Also, like the prior-discussed guide tubes, the guide tube  260  retracts within the body  255  as the device  250  is pressed against a work piece. 
     As shown in more detail in FIG. 32, the guide tube  260  is preferably in the form of an annular body. Thus, in this embodiment, the guide tube  260  includes an inner tube  264  attached to a radially inward annular end wall  263 . The guide tube  260  thus defines an annular bore  261  between its outer wall and the inner tube. The inner tube  260  itself defines an inner guide bore through which the screw bit  74  and drive shaft assembly  267  project as the guide tube is retracted within the body  255 . 
     To maintain the guide tube  260  within the bore  256  of the body  255 , and to limit the range of travel of the guide tube within that bore, the guide tube further includes an annular collar  262 . As shown in FIG. 31, the annular collar  262  is trapped within the bore  256  by an inward stop surface  257  at one end of the body  255 , and by a bearing cap  258  at the opposite end of the body. The bearing cap  258  can be similar to the cap  128  described above in structure and function. In this particular embodiment, the bearing cap  258  is preferably permanently attached to the body  255  to close the bore  256  and retain the annular collar  262  and spring  270  within the body. 
     Referring back to FIG. 31, the guide tube  260  is shown with the spring  270  in its operative position. Specifically, the spring  270  resides within the annular bore  261  defined by the tube. Thus, in contrast to the embodiments described above, the drive device  250  of the present embodiment has the drive assembly spring  270  integrated within the guide tube, rather than bearing against a terminal end of the guide tube. This approach allows the drive device  250  to be more compact, while still allowing the guide tube  260  to function as described above. 
     It should be understood that with the spring  270  extending into the guide tube  260 , side loading of a screw onto the screw bit  74  is problematic. With this embodiment, the screw to be driven is loaded into the open end of the guide tube. Preferably, the user can simply retract the guide tube to expose the screw bit  74  for placement of the screw thereon. This embodiment can make particularly good use of the magnet and magnetic bit feature described above to retain the screw on the bit as the guide tube  260  extends over the bit and screw. Of course, as the apparatus is used, the guide tube will bear against the work piece and will gradually retract within the body  255 , against the force of the spring  270 , as the screw is driven deeper into the work piece. 
     The body  255  and guide tube  260  of the screw holding and driving device  250  of the embodiment of FIGS. 31 and 32 is preferably formed of plastic. Most preferably, the guide tube  260  is formed of a transparent or translucent material to allow visualization of the driven screw within. In a specific embodiment, the individual elements of the guide tube  260  and body  255  can be attached with adhesive, or can be welded in a known manner. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. 
     For example, the present embodiments each utilize a coil spring concentrically disposed about the drive shaft. However, multiple springs are contemplated, whether concentric about the drive shaft or uniformly dispersed around the bore of the body of the device. Moreover, multiple concentric springs of different lengths can be utilized to provide varying spring force as the guide tube is pushed deeper into the body of the device. 
     Of course, while a coil spring is preferred for its simplicity, other resilient components or spring elements can be substituted that tend to bias the guide tube outward from the body of the device. Moreover, while a compression spring is preferred, an extension spring can be utilized with appropriate modification of the body and guide tube. For example, the extension spring can be attached at the front stop surface  146  of the body  104  and to the front stop surface  140  of the guide tube  106 . As the guide tube is pushed into the body during a screwing operation, the extension spring is extended, and then retracts when the axial force is removed to pull the guide tube to its extended position. 
     Likewise, while the present embodiments show replaceable driving bits, the bit can be fixed to the drive shaft or formed as part of the shaft. Similarly, the drive shaft itself can be replaceable. 
     There are a plurality of advantages of the present invention arising from the various features of the screw holding and driving device described herein. It will be noted that alternative embodiments of the screw holding and driving device of the present invention may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the screw holding and driving device that incorporate one or more of the features of the present invention and fall within the spirit and scope of the present invention as defined herein.