in describing particular embodiments of the present invention , specific terminology will be used for the sake of clarity . however , the invention is not intended to be limited to any specific terms used herein , and it is to be understood that each specific term includes all technical equivalents , which operate in a similar manner to accomplish a similar purpose . fig1 depicts : ( 1 ) a drill guide 10 according to the present invention in which the guide 10 includes a guide tube 20 having depth gauge features or markings 40 thereon ; and ( 2 ) a drill bit 50 insertable into and through the guide tube 20 for drilling bone . the drill guide 10 may function as a combination guide and depth gauge for simultaneously drilling a pilot hole ( s ) into bone and indicating the depth at which such hole ( s ) is drilled . in some instances , the drill guide 10 may be configured to interact with an aperture in a bone plate or other implantable device ( hereinafter , “ surgical device ”) to drill a corresponding pilot hole ( s ) for such aperture ( s ). a screw or other fixation mechanism may thereafter be inserted through the relevant aperture and into the pilot hole to secure the surgical device to the bone . referring to fig1 and 2 a - 2 b , guide tube 20 of drill guide 10 may include an elongate cylindrical body 21 forming a main portion of the tube 20 and having a bore 22 running therethrough along an axis . the bore 22 may extend from a proximal end 23 to a distal end 24 of the tube 20 ; and , likewise , a slot 31 may be formed through the tube 20 and may extend , generally , between proximal 23 and distal 24 ends . the slot 31 may be used to view the drill bit 50 as it travels within bore 22 . in one embodiment , particular indicia or a scale 40 may be positioned on body 21 adjacent slot 31 for determining the exact depth to which the drill bit 50 is inserted into bone . projecting from the main portion of guide tube 20 ( i . e ., cylindrical body 21 ) adjacent distal end 24 may be an extension 25 of the tube 20 formed integral therewith or as a separate component part . extension 25 may , in one embodiment , be generally cylindrical in shape and may have a chamfered section 33 on an external surface thereof for engaging with an aperture formed in a surgical device . extension 25 also , like guide tube 20 , has a bore 26 running therethrough . thus , the combination of bore 22 through tube 20 and bore 26 through extension 25 allows the drill bit 50 to be inserted completely through drill guide 10 . in a particular embodiment , bore 22 of tube 20 may form a first relatively wider section 27 , and bore 26 of extension 25 may define a second relatively narrower section 28 ( e . g ., in terms of diameter ) defining a stop surface 29 therebetween . in some embodiments , second section 28 defined by bore 26 may closely approximate the size and shape of a portion of drill bit 50 so as to serve as a guide and stabilize the bit 50 when inserted into bone . stated differently , as second section 28 defined by bore 26 may closely approximate the size and shape of a portion of drill bit 50 , such section 28 may act as a longitudinal guide stabilizing drill bit 50 as it is inserted into bone . stop surface 29 between first 27 and second 28 sections may also serve to limit the insertion depth of the drill bit 50 , as will be described in more detail below . housed within bore 22 of tube 20 may also be a spring 60 , as shown in detail in fig2 a - 2b . spring 60 may be a conventional helical spring , although other spring types are contemplated ; and such spring 60 may extend , in its expanded state , along the entirety of bore 22 of tube 20 . a distal end 62 of spring 60 may also abut stop surface 29 so as to allow spring 60 to be compressed within bore 22 , when desired . a movable guide 70 may also form part of drill guide 10 , such guide 70 being shown in detail in both fig1 and 2 a - 2 b . guide 70 may generally be configured to be situated within bore 22 of tube 20 , such that a radial flange 71 extending from the guide 70 may ride along an interior surface of bore 22 ( fig2 a - 2b ). guide 70 has a bore 72 extending therethrough , such bore 72 having a first tapered section 73 and a second generally straight section 74 . second straight section 74 of bore 72 may be configured to receive and interact with a portion of drill bit 50 , while first tapered section 73 may be configured to interact with a separate section of drill bit 50 , described in more detail below . radially extending flange 71 of guide 70 , and specifically a bottom surface 75 thereof , may also be configured to interact with a proximal end 61 of spring 60 to compress spring 60 in bore 22 of tube 20 , as shown best in fig2 a - b and fig4 . a protrusion 77 , shown in fig1 and 3 , may also extend from a surface of the guide 70 for interacting with the slot 31 or another channel in tube 20 , and thereby maintaining and / or aligning movable guide 70 appropriately as it travels along bore 22 of tube 20 ( e . g ., during drilling ). referring again to fig2 a - 2b , a top surface 79 of radially extending flange 71 may interact with a cap 80 inserted into the proximal end 23 of guide tube 20 . in one embodiment , cap 80 may include external threading ( not shown ), which interacts with internal threading ( not shown ) formed on an interior surface of tube 20 adjacent proximal end 23 . thus , cap 80 may be screwed into engagement with tube 20 . once cap 80 is secured within tube 20 as such , top surface 79 of flange 71 may interact with a distal end 81 or other surface of cap 80 thereby preventing movable guide 70 from being pushed out of bore 22 in tube 20 via spring 60 . in other words , movable guide 70 may be compressed between spring 60 and distal end 81 of cap 80 , thereby retaining guide 70 in tube 20 . accordingly , via the interaction between cap 80 and movable guide 70 , spring 60 may remain compressed ( to some minor degree ) at all times . in one embodiment , cap 80 may include a bore 82 therethrough with multiple sections , one such section being a distal section 83 having a diameter that is sized to receive a proximal section 76 of movable guide 70 . proximal section 76 of movable guide 70 may , therefore , be disposed within distal section 83 of bore 82 in cap 80 , and flange 71 of guide 70 may interact with distal end 81 of cap 80 . a second intermediate section 84 of bore 82 may be situated above distal section 83 , and may neck - down creating a reduced diameter section . such section 84 of bore 82 may optionally include threading to interact with corresponding threading formed on a section of drill bit 50 . depending on the dimensions of moveable guide 70 , intermediate section 84 of bore 82 , via the difference in diameter between distal section 83 and intermediate section 84 , may define a stop surface that contacts a proximal end 78 of movable guide 70 to assist in retaining the same within tube 20 . a final proximal section 85 of bore 82 through cap 80 may be sized similar to distal section 83 , thus defining a step between intermediate 84 and proximal 85 sections of bore 82 . one or more apertures 86 may also be disposed through cap 80 nearing proximal section 85 of bore 82 to allow a surgeon , nurse , or other skilled practitioner ( hereinafter , “ the user ”) to view a portion of the drill bit 50 as it is inserted through drill guide 10 . a flange 87 may also be arranged on cap 80 for abutting against a portion of tube 20 to thereby limit the insertion of cap 80 within bore 22 of tube 20 . referring again to fig1 , there is shown a drill bit 50 having a cutting section 51 , a tool engaging section 52 ( e . g ., for connecting to a power tool - type device ), and a shaft 53 running therebetween . shaft 53 may have a series of markers 54 thereon for determining a depth to which the drill bit 50 is inserted into bone ( i . e ., by aligning with a feature of the drill guide 10 ), and / or for determining whether the drill bit 50 is in a locked or unlocked orientation , as described more fully below . drill bit 50 may also include a tapered section 55 and a flange 56 adjacent the tapered section 55 . in one embodiment , flange 56 may include external threading thereon that may interact with the internal threading on intermediate section 84 of bore 82 through cap 80 . drill bit 50 may , in one embodiment , be generally cylindrical in shape , and may be sized for insertion through cap 80 and guide tube 20 ( including extension 25 ) of drill guide 10 . to assemble drill guide 10 , as shown in detail in fig1 , a user may first insert movable guide 70 , and specifically second section 74 thereof , into the proximal portion 61 of spring 60 , such that flange 71 of guide 70 engages a portion of spring 60 . then , the movable guide 70 and spring 60 construct may be inserted within bore 22 of guide tube 20 so that a distal end 62 of spring 60 may abut stop surface 29 . with these components assembled in the manner described , a user may then insert distal end 81 of cap 80 into proximal end 23 of tube 20 and screw cap 80 into tube until such a point as : ( 1 ) flange 87 of cap 80 abuts proximal end 23 of tube 20 ; ( 2 ) intermediate section 84 of bore 82 abuts proximal end 78 of movable guide 70 ; and / or ( 3 ) distal end 81 of cap 80 abuts flange 71 of guide 70 . in this configuration , movable guide 70 may move longitudinally along and within bore 22 of guide tube 20 to interact with drill bit 50 during drilling of bone . to be exact , since flange 71 of movable guide 70 contacts a portion of spring 60 , and a distal end 62 of spring 60 abuts stop surface 29 , such spring 60 may be compressed as guide 70 is moved axially within bore 22 of guide tube 20 . in other embodiments , drill guide 10 may be manufactured such that cap 80 is integral with tube 20 , creating a single monolithic structure in which moveable guide 70 and spring 60 are disposed . with the components of drill guide 10 assembled , drill bit 50 may be inserted within and through drill guide 10 ( e . g ., for drilling ) as follows . cutting section 51 of drill bit 50 may first be inserted through bore 82 in cap 80 , bore 72 in movable guide 70 , and partway through bore 22 in guide tube 20 . during this insertion , drill bit 50 may be advanced until such a point as flange 56 of bit 50 engages or abuts intermediate section 84 of bore 82 in cap 80 . since flange 56 may include external threading thereon , which may interact with the internal threading on intermediate section 84 of bore 82 , flange 56 , and thus drill bit 50 , may initially be precluded from traveling through intermediate section 84 of bore 82 of cap 80 ( e . g ., since the threading on intermediate section 84 may prevent movement of drill bit 50 distally without rotation thereof ). subsequently , a user may elect to rotate drill bit 50 about its longitudinal axis to screw flange 56 into engagement with intermediate section 84 of bore 82 . in this condition , i . e ., during engagement of flange 56 with intermediate section 84 , drill bit 50 may be locked in position in an axial direction within bore 22 , such that drill bit cannot travel along the axis of bore 22 without rotating drill bit 50 about the axis . such a locked configuration may be displayed to a user through the alignment of an indicator 54 on drill bit 50 with one or more apertures 86 in cap 80 , as shown in detail in fig3 . in particular , a specific reference marker 54 on drill bit 50 may be viewable through the one or more apertures 86 in cap 80 only when the drill bit 50 is situated in the locked condition . a user may therefore be informed as to when the drill bit 50 is disposed in the locked configuration and when it is not . with flange 56 screwed into engagement with intermediate section 84 of bore 82 of cap 80 , drill bit 50 may act as a manipulation tool for manipulating drill guide 10 ( e . g ., since drill bit 50 is locked to drill guide 10 ). as such , it is possible for a user to manipulate drill guide 10 via drill bit 50 and engage chamfered section 33 of extension 25 with an aperture in a surgical device ( not shown ) without fear of disconnection between drill bit 50 and drill guide 10 . that is , drill bit 50 may first be connected with a drill , and drill guide 10 may thereafter be engaged with drill bit 50 , such that the two are essentially locked together . this would allow a user to perform the step of engaging chamfered section 33 of extension 25 with an aperture in a surgical device ( not shown ) and then to drill directly afterward without having to align the drill bit 50 into the engaged drill guide 10 . once chamfered section 33 of guide tube 20 is engaged to an appropriate aperture in a surgical device , a user may then continue to rotate drill bit 50 about its longitudinal axis to cause the threading on flange 56 to disengage with the corresponding threading on intermediate section 84 of bore 82 through cap 80 . in this condition , as shown in detail in fig4 , flange 56 of drill bit 50 may be engaged with proximal end 78 of movable guide 70 , and / or tapered section 55 of drill bit 50 may be engaged with tapered section 73 of bore 72 through guide 70 . accordingly , movement of drill bit 50 in an axial direction may cause corresponding movement of movable guide 70 within bore 22 of guide tube 20 . additionally , as flange 71 of movable guide 70 may be engaged with spring 60 , there may be some resistance to such movement , thereby providing a user with a tactile sensation that the drill bit 50 is smoothly gliding through drill guide 10 . such resistance may also keep movable guide 70 disposed against tapered section 55 and flange 56 of drill bit 50 . during movement of drill bit 50 through guide tube 20 via movable guide 70 , as discussed above , a user may also view the depth gauge features or markings 40 on tube 20 in conjunction with a particular reference marker 54 on drill bit 50 , which indicates the depth at which bit 50 is inserted into bone . stated differently , as drill bit 50 is moved longitudinally or axially through guide tube 20 , a user may view a particular reference marker 54 on such bit 50 through slot 31 in tube 20 , and the position of such marker 54 in relation to the depth gauge markings 40 on tube 20 may indicate the depth at which drill bit 50 is inserted into bone . the same function may be provided by viewing protrusion 77 on movable guide 70 through slot 31 . for instance , a user may view the aforementioned reference marker 54 ( or protrusion 77 ) traveling from a marking 40 on guide tube 20 reading zero ( 0 ) millimeters to a marking 40 reading twenty ( 20 ) millimeters and thereby know that the drill bit 50 has been inserted twenty ( 20 ) millimeters into bone . during such axial movement of drill bit 50 , movable guide 70 may also be stabilized within bore 22 of guide tube 20 via the interaction between protrusion 77 on guide 70 and slot 31 formed through tube 20 ( e . g ., such guide 70 may be restricted from unwanted rotation within tube 20 as drill bit 50 is rotated for drilling ). thus , in some instances , protrusion 77 may serve a dual function . referring still to fig4 , upon moving drill bit 50 ( and thus movable guide 70 ) a sufficient distance in the distal direction , protrusion 77 on movable guide 70 may engage with a portion of slot 31 in guide tube 20 , thereby preventing further movement of drill bit 50 distally . thus , such portion of slot 31 may act as a depth - limiting feature of drill guide 10 for limiting the maximum depth to which the drill bit 50 may be inserted into bone ; although , as noted above , it is also contemplated that a user may simply stop drilling when the desired depth for drilling has been reached . it is notable that , in the unlocked condition described above , the reference marker 54 on drill bit 50 indicating that such bit 50 is in a locked condition will no longer be viewable through apertures 86 in cap 80 . thus , a user is informed that drill bit 50 is in the unlocked state and is freely movable within bore 22 in guide tube 20 once flange 56 on drill bit 50 is disengaged from intermediate section 84 of bore 82 through cap 80 . with the initial pilot hole drilled according to the above - described method , a user may then disengage chamfered section 33 of extension 25 from the aperture in the surgical device and continue to drill another pilot hole ( s ) utilizing a different aperture ( s ) in the surgical device . this process may be repeated , as necessary , until all pilot holes are drilled . subsequently , the user may insert a fixation mechanism ( not shown ), such as , for example , a bone screw or fixation pin through the aperture in the surgical device and into the corresponding pilot hole . the surgical device may then be secured to bone via the fixation mechanism ( s ) inserted into the pilot hole ( s ). in one embodiment , to remove drill guide 10 from engagement with the surgical device , a user may simply retract drill bit 50 proximally until such a point as flange 56 abuts intermediate section 84 of bore 82 through cap 80 . the user may then rotate drill bit 50 so that the threading on flange 56 reengages with the threading on intermediate section 84 of bore 82 . this places drill bit 50 back into its locked state , which may be conveyed to a user via a reference marker 54 on drill bit 50 , which is viewable through aperture ( s ) 86 in cap ( fig3 ). with drill bit 50 in its locked state , a user may then simply remove the drill bit 50 / drill guide 10 construct ( e . g ., as one piece ) from contact with the surgical device . thereafter , the user may elect to continue to rotate the drill bit 50 , such that flange 56 disengages with intermediate section 84 of bore 82 and drill bit 50 is removed or separated from drill guide 10 . the drilling process , at this stage , may be complete , and a user may elect to utilize the drill guide 10 and drill bit 50 in another surgical procedure , if desired . in the devices depicted in the figures , particular structures are shown that are adapted to provide an improved drilling apparatus and / or allow for an improved method of drilling bone . the invention also contemplates the use of any alternative structures for such purposes , including structures having different lengths , shapes , and / or configurations . for example , although drill guide 10 has been described as engaging an aperture in a surgical device , it is equally contemplated that a portion of drill guide 10 ( e . g ., chamfered section 33 ) may be configured to interact directly with bone . in this embodiment , chamfered section 33 may include teeth or other such serrations so that , once engaged with bone , drill guide 10 may be stabilized with respect thereto . in this condition , drilling would take place as described above , except that drill guide 10 would directly contact bone instead of contacting an intermediate surgical device ( e . g ., a bone plate aperture , etc .) it is also contemplated that the aforementioned teeth or serrations may be included on chamfered section 33 , and such section 33 may simultaneously engage an intermediate surgical device and bone during drilling . as another example , while drill bit 50 may be locked axially with respect to drill guide 10 through interaction of threading on the drill bit 50 with threading on a portion of guide 10 , other locking mechanisms are contemplated . for instance , a portion of drill bit 50 may be designed to be press - fit into a portion of cap 80 ( or another portion of guide 10 ), such that drill bit 50 is lockable in an axial direction within bore 22 . in other words , slight differences in dimensions between one section of drill bit 50 and a corresponding section of cap 80 ( or another section of guide 10 ) may cause drill bit 50 to become fixed within cap 80 ( or the other section of guide 10 ) when such sections interact . subsequently , upon application of sufficient force , drill bit 50 may be driven through the “ press - fit ” region , through the remainder of drill guide 10 , and into bone . thus , with this mechanism , drill bit 50 may be provisionally locked within bore 22 in an axial direction . in another example of this type of “ press - fit ” configuration , an outwardly extending flange on drill bit 50 may interact with two inwardly extending flanges on cap 80 ( or guide 10 ). the outwardly extending flange may be dimensioned to create a slight dimensional interference with each of the inwardly extending flanges . between the inwardly extending flanges may be an annular recess . the outwardly extending flange of drill bit 50 may pressed to pass the initial inwardly extending flange with a force that overcomes the dimensional interference and allows the outwardly extending flange to be temporarily retained within the annular recess , thereby locking the drill bit 50 to the drill guide 10 in a manner similar to that described above . a protrusion and detent mechanism may also be used in place of the aforementioned locking structures . for example , a protrusion on drill bit 50 may selectively engage with a corresponding detent in cap 80 ( or another portion of guide 10 ) so as to provisionally lock drill bit 50 axially within bore 22 of tube 20 . after such engagement , a user may then cause the protrusion on drill bit 50 to disengage with the detent in cap 80 ( or other portion of guide 10 ) to allow drill bit 50 to move within bore 22 in tube 20 and into bone . likewise , it is also contemplated that cap 80 ( or the other portion of guide 10 ) may contain the protrusion and drill 50 the detent . it is therefore apparent that other locking mechanisms beyond that disclosed in the main embodiment may be used . although the invention herein has been described with reference to particular embodiments , it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention . it is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims . it will also be appreciated that the various dependent claims and the features set forth therein can be combined in different ways than presented in the initial claims . it will also be appreciated that the features described in connection with individual embodiments may be shared with others of the described embodiments .
a drill guide for drilling bone comprising a housing having a bore running through the housing is disclosed . in one embodiment , the drill guide may comprise a locking member coupled to the housing that is adapted to engage with a locking portion of a drill bit to lock the drill bit axially within the housing . the locking member may also be adapted to disengage with the drill bit to allow the drill bit to move within the bore of the housing and be inserted into bone . a movable guide may also be provided with the drill guide , such movable guide including a bore for receiving a portion of the drill bit and allowing the same to move axially within the housing . methods of using the aforementioned drill guide are also disclosed .