the following description is not intended to limit the invention to the forms disclosed herein . consequently , variations and modifications commensurate with the following teachings , skill and knowledge of the relevant art , are within the scope of the present invention . the embodiments described herein are further intended to explain known modes of practicing the invention and to enable others skilled in the art to utilize the invention in such , or other , embodiments and with various modifications required by the particular applications ( s ) or use ( s ) of the present invention . certain terminology is used in the following description for convenience only and is not limiting . the words “ lower ” and “ upper ” designate directions in the drawings to which reference is made . as used in the claims and in the corresponding portion of the specification , the word “ a ” means “ at least one ”. further , unless otherwise defined the word “ about ” when used in conjunction with a numerical value means a range of values corresponding to the numerical value plus or minus ten percent of the numerical value . still further , the word “ or ” has the meaning of a boolean inclusive “ or ”. for example , the phrase “ a or b ” means “ a ” alone or “ b ” alone or both “ a ” and “ b ”. in some drawings which contain a plurality of a certain element , less than all of the instances of that element have been labelled in order to avoid excessive labelling obstructing the figure itself . furthermore , in some instances a single element is labelled in multiple locations within a single drawing to provide clarity . referring to the drawings in detail and in particular to fig1 , there is shown a first embodiment of the drill bit guide assembly generally designated 100 . the drill bit guide assembly 100 includes a guide member 102 . the guide member 102 is comprised of at least a portion of a fixed bore 104 . the central axis of the fixed bore 104 defines a reference axis 112 . furthermore , the guide member 102 may include and / or provide a point of attachment for a handle ( not shown in fig1 ). a bore selection member 108 is also provided in relation to the guide member 102 . in this embodiment , the bore selection member 108 may be affixed to the drill bit guide assembly 100 in a manner in which the bore selection member 108 may rotate about an axle 109 . the bore selection member 108 may contain a plurality of selectable bores 106 each of which may be alignable with the fixed bore 104 such that a drill bit 110 may pass through both the fixed bore 104 and a selectable bore 106 along the reference axis 112 ( e . g ., by rotation of the bore selection member 108 about the axle 109 ). the selectable bores 106 may have different diameters . a user may choose a selectable bore 106 that is similar in size to the drill bit 110 being utilized . the similar diameters of the drill bit 110 and a selectable bore 106 may allow the selectable bore 106 to guide and stabilize the drill bit 110 during use . similarly , the fixed bore 104 may be of a similar diameter to the drill bit 110 providing further guidance and stability . alternatively , the fixed bore 104 may be of a larger diameter than the drill bit 110 such that the drill bit 110 does not necessarily contact the walls of the fixed bore 104 . an axle 109 may pass through a central bore 111 disposed within the bore selection member 108 about which the bore selection member 108 may rotate . another embodiment of a drill bit guide assembly 200 is shown in fig2 . a guide member 102 includes at least a portion of a fixed bore 104 . a bore selection member 208 may be slidably affixed to the drill bit guide assembly 200 . the bore selection member 208 may include a plurality of selectable bores 106 which may be arranged linearly such that each may be aligned with the reference axis 112 allowing a drill bit 110 to pass through both the fixed bore 104 and a selectable bore 106 . the bore selection member 208 may be attached in any well - known manner that provides relative movement between the bore selection member 208 and the guide member 102 . one example is a tongue and groove in which one of the bore selection member 208 and the guide member 102 comprises a groove along one or more sides and in which a tongue is disposed upon the other of the bore selection member 208 or the guide member 102 in order to guide the bore selection member 208 as it is moved relative to the guide member 102 . fig3 - 18 pertain to embodiments comprising a rotatable bore selection member similar to that of fig1 . fig3 & amp ; 4 depict an embodiment of a bore selection member 300 comprised of a plurality of selectable bores 306 . the bore selection member 300 is further comprised of a plurality of locking cavities 314 which may be engageable with one or more locking pins to restrict movement of the bore selection member 300 relative to the drill bit guide assembly as will be discussed in greater detail below . a central bore 311 may be disposed near the center of the bore selection member 300 through which an axle may be disposed . furthermore , a plurality of indicia 316 may be disposed upon a perimeter surface 308 of the bore selection member 300 to denote which selectable bore 306 is currently aligned with the fixed bore . fig5 - 7 illustrate an embodiment of a drill bit guide assembly 500 . the guide member 502 comprises at least a portion of a fixed bore 504 . the bore 504 may pass through a first and a second portion of the guide member 502 wherein the first and second portion are spaced apart by the bore selection member 508 . an axle 512 is disposed upon the guide member 502 about which a bore selection member 508 may rotate . a locking pin 514 is disposed upon the guide member 500 which may engage a locking cavity ( e . g ., locking cavity 314 of fig3 ) disposed upon a bore selection member 508 in order to index the selectable bores 506 . in the embodiment shown , the locking pin 514 is disposed on a portion of the guide member 502 distal to the bore selection member 508 . importantly , the locking pin 514 , or any other type of indexing member , may be disposed proximal to the bore selection member 508 . further , an indexing member may be disposed adjacent to the perimeter surface ( e . g ., perimeter surface 308 of fig3 ) of the bore selection member 508 and engageable with a corresponding indexing member disposed upon the bore selection member 508 . in any regard , a biasing member may be provided to retain a bore selection member 508 in a preferred location such that a user may manipulate a bore selection member 508 relative to an axle 512 to select a selectable bore 506 . a biasing member may be a coiled spring , for example . in the illustrated example , an indicator comprised of a viewing window 520 may be disposed upon the guide member 500 to denote an indicium 516 disposed upon the bore selection member 508 correlating to the selectable bore 506 which is aligned with the fixed bore 504 . wth reference to fig1 , another embodiment of a drill bit guide assembly 1800 is shown that includes another manner in which a selected one of the selectable bores 1806 is indicated as being aligned with a fixed bore 1804 . as above , the bore selection member 1808 may include indicia 1816 that may correspond with respective ones of the selectable bores 1806 . in this regard , an indicator 1820 may be positioned adjacent to an indicium 1816 corresponding to the selectable bore 1806 aligned with the fixed bore 1804 . this may provide an indication of the selectable bore 1806 that is aligned with the fixed bore 1804 that is provided by simply viewing the drill bit guide assembly 1800 . fig7 depicts an attaching mechanism comprised of threads 507 is disposed at a distal end 518 of the guide member 500 to receive a threaded extension member ( e . g ., extension member 810 of fig8 ). the threads 507 allow extension members ( e . g ., extension member 810 of fig8 ) of various size to be interchanged as needed during use . one of ordinary skill in the art will appreciate that different lengths and diameters may be preferred at different times without needing to change tools . with reference to fig8 - 9 , another embodiment of a drill bit guide assembly 800 is comprised of a guide member 802 which is comprised of at least a portion of a fixed bore 804 . the drill bit guide assembly 800 is further comprised of a rotatable bore selection member 808 . the bore selection member is comprised of a plurality of selectable bores 806 . a distal end 818 of the drill bit guide assembly 800 may have an extension member 810 with a wide distal surface to rest externally against a patient &# 39 ; s tissue . this may be in contrast to a narrow tip which may allow the distal end 818 to be inserted into an incision ( e . g . extension member 1610 in fig1 a & amp ; 16b ). the extension members ( e . g . 810 and 1610 ) may be interchangeable . fig1 is a cross sectional view of an embodiment of a drill bit guide assembly 800 similar to that of fig8 and 9 . a guide member 802 may comprise at least a portion of a fixed bore 804 the central axis of which comprises a reference axis 812 . the drill bit guide assembly 800 may be further comprised of a rotatable bore selection member 808 comprised of a plurality of selectable bores 806 . a distal end 818 of the drill bit guide assembly 800 may be comprised of an attachment mechanism comprising threads 807 which are engageable to corresponding threads on an extension member 810 . alternatively , the attachment mechanism may be a friction or interference fitting , a clip and / or latch system , or any other well - known attaching device . in another embodiment of a drill bit guide assembly 1100 shown in fig1 , a distal end 1118 may be elongated to provide improved stability to the drill bit . the elongated portion which comprises at least a portion of a fixed bore 1104 may be a portion of the guide member 1102 itself or may be an attachable extension member 1110 . in this embodiment the guide member 1102 houses at least a portion of the fixed bore 1104 and a bore selection member 1108 . the bore selection member is comprised of a plurality of selectable bores 1106 . in an embodiment of a drill bit guide assembly 1200 shown in fig1 , an elongated extension member 1210 may be disposed upon a distal end 1218 of the drill bit guide assembly . the extension member 1210 may be attachable to the guide member 1202 with an attaching mechanism comprised of threads which are concealed and not visible in fig1 . different lengths and diameters may be preferred for different tasks and the interchangeability of extension members 1210 may allow for expedient adaptation of the assembly . fig1 - 15 illustrate an embodiment of a guide member 1300 with the bore selection members removed for illustrative purposes . a guide member 1300 may comprise at least a portion of a fixed bore 1304 . an indicator comprised of a viewing window 1316 may be disposed upon the guide member 1300 . the guide member 1300 may further comprise an axle 1312 about which a bore selection member ( e . g . bore selection member 308 of fig3 ) may be disposed . a locking pin 1314 may be disposed upon the guide member 1302 to lockably engage a locking bore on a bore selection member . an extension member 1310 may be attachable to the guide member 1302 or may alternately be permanently attached or monolithic with the guide member 1302 . a drill bit guide assembly 1600 that includes two rotatable bore selection members 1608 is shown in fig1 - 17 . the bore selection members 1608 are disposed about axles ( e . g . axles 1312 in fig1 ) allowing a selectable bore 1606 to be aligned with the fixed bore 1604 and the reference axis 1612 . an upper bore selection member 1608 a may include selectable bores 1606 with similar or equal diameters to the selectable bores 1606 of a lower bore selection member 1608 b . in this scenario , if a drill bit ( e . g ., drill bit 110 in fig1 ) with a small diameter relative to fixed bore 1604 were used , each of the bore selection members 1608 may be positioned such that a selectable bore 1606 on each bore selection member 1608 of similar diameter to the drill bit may be used to guide the drill bit . furthermore , in such a scenario , the drill bit may contact the walls of the selectable bores 1606 and may or may not contact the walls of the fixed bore 1604 . in another embodiment of a drill bit guide assembly 1600 the diameters of the selectable bores 1606 of the lower bore selection member 1608 b may be different than those of the upper bore selection member 1608 a . for example , the diameters of the selectable bores 1606 of the lower bore selection member 1608 b may be smaller than the selectable bores 1606 of the upper bore selection member 1608 a . this scenario would allow a relatively small drill bit to pass freely through a selectable bore 1606 of the upper bore selection member 1608 a and engage a selectable bore 1606 of similar diameter to the drill bit in the lower bore selection member 1608 b . accordingly , each selectable bore 1606 may be sized such that its diameter is different than each other selectable bore 1606 . such an embodiment may allow a greater variety of selectable bore 1606 diameters to be disposed upon the drill bit guide assembly 1600 than if the plurality of bore selection members 1608 housed selectable bores 1606 of similar diameters to the other bore selection members 1608 . accordingly , the drill bit guide assembly 1600 may function with a greater variety of drill bit diameters and reduce clutter and confusion which may be caused by the necessity for multiple traditional drill bit guides . a detachable extension member 1610 may comprise a lower guide member 1602 b and lower bore selection member 1608 b . alternately , the lower guide member 1602 b may be permanently attached or monolithic with the upper guide member 1602 a . those skilled in the art will appreciate that changes could be made to the embodiments described above without departing from the broad inventive concept thereof . it is understood , therefore , that this invention is not limited to the particular embodiments disclosed , but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims . while the invention has been illustrated and described in detail in the drawings and foregoing description , such illustration and description is to be considered as exemplary and not restrictive in character . for example , certain embodiments described hereinabove may be combinable with other described embodiments and / or arranged in other ways ( e . g ., process elements may be performed in other sequences ). accordingly , it should be understood that only the preferred embodiment and variants thereof have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected .
drill bit guide assemblies related to surgical operations for guiding and stabilizing a drill bit . a guide member houses a fixed bore through which a drill bit may pass . the guide member may also house a bore selection member which houses a plurality of selectable bores . the selectable bores may have a variety of diameters such that a user may choose the selectable bore corresponding to the drill bit diameter being used and align that selectable bore with the fixed bore such that the drill bit may pass through the length of the assembly along the reference axis . the similar diameters of the selectable bore and the drill bit may cause the assembly to stabilize and guide the drill bit .