Perforator

Claim 2

A surgical perforator for drilling a hole in a bone structure, said perforator having a drill bit configured into a hollow cylindrical wall having a bottom end, a cutting edge formed in said wall at said bottom end and lying long the circumference of said cylindrical wall and being in line therewith, a movable shield lying along said circumference and disposed adjacent to said cutting edge, said shield extending at least in line with said cutting edge to prevent said cutting edge from cutting, said shield movable by a resistive force when said perforator is in the drilling mode so as to uncover said cutting edge and said shield automatically returning to its original position when said resistive load ceases, and means for attaching said drill bit to a drill motor to impart rotary motion to said drill bit.

Claim 3

A surgical perforator for drilling a hole in a bone structure as claimed in claim 1 wherein said drill bit includes a horizontal slot formed in said wall adjacent to said shield to provide a predetermined gap to allow the automatic displacement of said shield when the resistive load is applied and ceases.

Claim 4

A surgical perforator for drilling a hole in a bone structure as claimed in claim 2 including a vertical slot formed in said wall between said cutting edge and said shield wherein said shield cooperates with said cutting edge to permit exposure of said cutting edge when a predetermined resistive load is applied thereto.

Claim 5

A surgical perforator for drilling a hole in a bone structure as claim 3 including slots cut into said wall to form said cutting edge.

Claim 6

A surgical perforator for drilling a hole in a bone structure as claimed in claim 3 wherein said wall means defines the width of the cut in said bone structure wherein a plug of said bone remains after said cutting operation is completed.

Claim 7

A surgical perforator for drilling a hole in a bone structure as claimed in claim 1 wherein said shield is formed from an elongated member having a top, a bottom and opposing sides and configured into an arcuate shape to fit into a recess formed in said wall to form a continuous annular wall, said bottom extending at least a distance to cover said cutting edge, and resilient and flexible means for biasing said shield to cover said cutting edge and permitting said shield to retract when bearing against said bone structure and encountering a predetermined resistive load and automatically retracting to the original position when said resistive load ceases.

Claim 8

A surgical perforator for drilling a hole in a bone structure as claimed in claim 6 wherein said resilient and flexible means includes a coil spring inserted into a hole formed in said top and bearing against said wall.

Claim 9

A surgical perforator for drilling a hole in a bone structure as claimed in claim 7 wherein said perforator has a central axis, a post having a shank portion and head portion, said shank portion being affixed to said top of said shield and extending through an elongated passage extending through said wall parallel to said central axis and said head extending above said wall for limiting displacement of said shield.

Claim 10

A surgical perforator for drilling a hole in a bone structure as claimed in claim 1 including means for preventing said perforator from penetrating into said drilled passage a predetermined amount after said drill bit ceases cutting.

Claim 11

A surgical perforator for drilling a hole in a bone structure as claimed in claim 9 wherein said drill bit includes a central axis, said means for preventing penetration includes a threaded screw having an elongated shank threaded at the proximal and distal ends and coaxially disposed relative to said central axis and extending through said drill bit, a center driver threadably supported to said threaded screw at the distal end and having a bottom surface formed with a knurled surface adapted to engage the surface of the bone structure and a centrally disposed guide pin extending from the end of said threaded screw and adapted to penetrate said bone structure, stop pins, a bridge extending through diametrically disposed vertical slots formed in said wall for supporting said stop pins externally of said drill bit, said bridge being supported for rotary motion to said threaded screw between said threaded portions on the distal and proximal end of said threaded screw, and latch means to permit said threaded screw to be positioned by rotating through fixed threads or by rectilinear movement, spring means acting on one end of said threaded to urge said threaded screw to a deployed position, wherein when said threaded screw is in said deployed position said guide pin and knurled surface engage said bone structure to be maintained in a nonrotating condition and said stop pins rotate with said drill bit and moves with said threaded screw to maintain a predetermined distance from the surface of said bone structure as said drill bit penetrates the bone structure, and said threaded screw rotates with said drill bit when said resistive load ceases whereby further penetration of said drill bit will place said stop pins to bear against said bone structure and prevent further penetration of said drill bit.

Claim 12

A surgical perforator for drilling a hole in a bone structure as claimed in claim 10 including a latch mechanism having a main body extending through a lateral bore formed in said wall, a straight through passage parallel to said central axis formed in said main body, a portion of said straight through passage having threads formed therein and complementing the threads of said threaded screw and releasable spring means biasing said threads into engagement and the end of said main body being accessible to urge said main body in a direction to disengage said threads, whereby said threaded screw is permitted to be positioned longitudinally by said spring means on the top of said screw.

Claim 13

A surgical perforator for drilling a hole in a bone structure as claimed in claim 10 including a shoulder formed between said distal and proximal threaded portions of said threaded screw and said center driver bearing against said shoulder.

Claim 14

A cranial perforator for drilling a hole in a bone structure comprising a drill bit configured into a hollow cylindrical wall having a top end, a bottom end, a cutting edge formed in said wall at said bottom end and lying long the circumference of said cylindrical wall and being along line therewith, a movable shield lying in said circumference and disposed adjacent to said cutting edge, said shield extending at least in line with said cutting edge to prevent said cutting edge from cutting, said shield movable by a resistive force when said perforator is in the drilling mode so as to uncover said cutting edge and said shield automatically returning to its original position when said resistive load ceases, and a centrally disposed central shaft extending from said top and adapted to be attached to a chuck of said drill motor to impart rotary motion to said drill bit.

Claim 15

A cranial perforator for drilling a hole in a bone structure comprising a drill bit configured into a hollow cylindrical wall having a top end, a bottom end, a cutting edge formed in said wall at said bottom end and lying long the circumference of said cylindrical wall and being along line therewith, a movable shield lying in said circumference and disposed adjacent to said cutting edge, said shield extending at least in line with said cutting edge to prevent said cutting edge from cutting, said shield movable by a resistive force when said perforator is in the drilling mode so as to uncover said cutting edge and said shield automatically returning to its original position when said resistive load ceases, and a centrally disposed central shaft extending from said top and adapted to be attached to a chuck of said drill motor to impart rotary motion to said drill bit.

Claim 16

A cranial perforator for drilling a hole in a bone structure as claimed in claim 13 wherein said drill bit includes a horizontal slot formed in said wall adjacent to said shield to provide a predetermined gap to allow the automatic displacement of said shield when the resistive load is applied and ceases.

Claim 17

A cranial perforator for drilling a hole in a bone structure as claimed in claim 14 including a vertical slot formed in said wall between said cutting edge and said shield wherein said shield cooperates with said cutting edge to permit exposure of said cutting edge when a predetermined resistive load is applied thereto.

Claim 18

A cranial perforator for drilling a hole in a bone structure as claim 15 including slots cut into said wall to form said cutting edge.

Claim 19

A cranial perforator for drilling a hole in a bone structure as claimed in claim 15 wherein said wall means defines the width of the cut in said bone structure wherein a plug of said bone remains after said cutting operation is completed.

Claim 20

A cranial perforator for drilling a hole in a bone structure as claimed in claim 14 including means for preventing said perforator from penetrating into said drilled passage a predetermined amount after said drill bit ceases cutting.

Claim 21

A cranial perforator for drilling a hole in a bone structure as claimed in claim 18 wherein said drill bit includes a central axis, said means for preventing penetration includes a threaded screw having an elongated shank threaded at the proximal and distal ends and coaxially disposed relative to said central axis and extending through said drill bit, a center driver threadably supported to said threaded screw at the distal end and having a bottom surface formed with a knurled surface adapted to engage the surface of the bone structure and a centrally disposed guide pin extending from the end of said threaded screw and adapted to penetrate said bone structure, stop pins, a bridge extending through diametrically disposed vertical slots formed in said wall for supporting said stop pins externally of said drill bit, said bridge being supported for rotary motion to said threaded screw between said threaded portions on the distal and proximal end of said threaded screw, and latch means to permit said threaded screw to be positioned by rotating through fixed threads or by rectilinear movement, spring means acting on one end of said threaded to urge said threaded screw to a deployed position, wherein when said threaded screw is in said deployed position said guide pin and knurled surface engage said bone structure to be maintained in a nonrotating condition and said stop pins rotate with said drill bit and moves with said threaded screw to maintain a predetermined distance from the surface of said bone structure as said drill bit penetrates the bone structure, and said threaded screw rotates with said drill bit when said resistive load ceases whereby further penetration of said drill bit will place said stop pins to bear against said bone structure and prevent further penetration of said drill bit.

Claim 22

A cranial perforator for drilling a hole in a bone structure as claimed in claim 19 including a latch mechanism having a main body extending through a lateral bore formed in said wall, a straight through passage parallel to said central axis formed in said main body, a portion of said straight through passage having threads formed therein and complementing the threads of said threaded screw and releasable spring means biasing said threads into engagement and the end of said main body being accessible to urge said main body in a direction to disengage said threads, whereby said threaded screw is permitted to be positioned longitudinally by said spring means on the top of said screw.

Claim 23

A cranial perforator for drilling a hole in a bone structure as claimed in claim 20 including a shoulder formed between said distal and proximal threaded portions of said threaded screw and said center driver bearing against said shoulder.

Claim 24

A cranial drill for drilling a hole in a bone structure comprising a drill bit configured into a hollow cylindrical wall having a closed top, an opened bottom end, a cutting edge formed in said wall at said bottom end and lying along the circumference of said cylindrical wall and being in line therewith, a movable shield lying along said circumference and disposed adjacent to said cutting edge, said shield extending at least in line with said cutting edge to prevent said cutting edge from cutting, said shield movable by a resistive force when said perforator is in the drilling mode so as to uncover said cutting edge and said shield automatically returning to its original position when said resistive load ceases, and a central shaft extending from said top for attaching said drill bit to a drill motor to impart rotary motion to said drill bit.

Claim 25

A cranial drill for drilling a hole in a bone structure comprising a drill bit configured into a hollow cylindrical wall having a closed top, an opened bottom end, a cutting edge formed in said wall at said bottom end and lying along the circumference of said cylindrical wall and being in line therewith, a movable shield lying along said circumference and disposed adjacent to said cutting edge, said shield extending at least in line with said cutting edge to prevent said cutting edge from cutting, said shield movable by a resistive force when said perforator is in the drilling mode so as to uncover said cutting edge and said shield automatically returning to its original position when said resistive load ceases, and a central shaft extending from said top for attaching said drill bit to a drill motor to impart rotary motion to said drill bit.

Claim 26

A cranial drill for drilling a hole in a bone structure as claimed in claim 22 wherein said shield is formed from an elongated member having a top, a bottom and opposing sides and configured into an arcuate shape to fit into a recess formed in said wall to form a continuous annular wall, said bottom extending at least a distance to cover said cutting edge, and resilient and flexible means for biasing said shield to cover said cutting edge and permitting said shield to retract when bearing against said bone structure and encountering a predetermined resistive load and automatically retracting to the original position when said resistive load ceases.

Claim 27

A cranial drill for drilling a hole in a bone structure as claimed in claim 23 wherein said perforator has a central axis, a post having a shank portion and head portion, said shank portion being affixed to said top of said shield and extending through an elongated passage extending through said wall parallel to said central axis and said head extending above said wall for limiting displacement of said shield.

Claim 28

A cranial drill for drilling a hole in a bone structure as claimed in claim 22 including means for preventing said perforator from penetrating into said drilled passage a predetermined amount after said drill bit ceases cutting.

Claim 29

A cranial drill for drilling a hole in a bone structure as claimed in claim 25 wherein said drill bit includes a central axis, said means for preventing penetration includes a threaded screw having an elongated shank threaded at the proximal and distal ends and coaxially disposed relative to said central axis and extending through said drill bit, a center driver threadably supported to said threaded screw at the distal end and having a bottom surface formed with a knurled surface adapted to engage the surface of the bone structure and a centrally disposed guide pin extending from the end of said threaded screw and adapted to penetrate said bone structure, stop pins, a bridge extending through diametrically disposed vertical slots formed in said wall for supporting said stop pins externally of said drill bit, said bridge being supported for rotary motion to said threaded screw between said threaded portions on the distal and proximal end of said threaded screw, and latch means to permit said threaded screw to be positioned by rotating through fixed threads or by rectilinear movement, spring means acting on one end of said threaded to urge said threaded screw to a deployed position, wherein when said threaded screw is in said deployed position said guide pin and knurled surface engage said bone structure to be maintained in a nonrotating condition and said stop pins rotate with said drill bit and moves with said threaded screw to maintain a predetermined distance from the surface of said bone structure as said drill bit penetrates the bone structure, and said threaded screw rotates with said drill bit when said resistive load ceases whereby further penetration of said drill bit will place said stop pins to bear against said bone structure and prevent further penetration of said drill bit.

Claim 30

A cranial drill for drilling a hole in a bone structure as claimed in claim 26 including a shoulder formed between said distal and proximal threaded portions of said threaded screw and said center driver bearing against said shoulder.

Claim 31

A cranial drill for drilling a hole in a bone structure as claimed in claim 27 including a latch mechanism having a main body extending through a lateral bore formed in said wall, a straight through passage parallel to said central axis formed in said main body, a portion of said straight through passage having threads formed therein and complementing the threads of said threaded screw and releasable spring means biasing said threads into engagement and the end of said main body being accessible to urge said main body in a direction to disengage said threads, whereby said threaded screw is permitted to be positioned longitudinally by said spring means on the top of said screw.

Claim 32

A surgical perforator for drilling a hole in a bone structure, said perforator having a drill bit configured into a hollow cylindrical wall having a bottom end, a cutting edge formed in said wall at said bottom end and lying along the circumference of said cylindrical wall and being in line therewith, a movable shield lying along said circumference and disposed adjacent to said cutting edge, said shield extending at least in line with said cutting edge to prevent said cutting edge from cutting, said shield movable by a resistive force when said perforator is in the drilling mode so as to uncover said cutting edge and said shield automatically returning to its original position when said resistive load ceases, means for attaching said drill bit to a drill motor to impart rotary motion to said drill bit and clutching means responsive to the movement of said shield to declutch said drill bit from said drill motor.

Claim 33

A surgical perforator for drilling a hole in a bone structure, said perforator having a drill bit configured into a hollow cylindrical wall having a bottom end, a cutting edge formed in said wall at said bottom end and lying along the circumference of said cylindrical wall and being in line therewith, a movable shield lying along said circumference and disposed adjacent to said cutting edge, said shield extending at least in line with said cutting edge to prevent said cutting edge from cutting, said shield movable by a resistive force when said perforator is in the drilling mode so as to uncover said cutting edge and said shield automatically returning to its original position when said resistive load ceases, means for attaching said drill bit to a drill motor to impart rotary motion to said drill bit and clutching means responsive to the movement of said shield to declutch said drill bit from said drill motor.

Claim 34

A surgical perforator as claimed in claim 29 wherein said means for attaching the drill bit to said drill motor includes a stem, a driver disposed coaxially relative to said stem and being rotatable relative thereto, said clutch means including a vertical rod disposed in a vertical passage in said drill bit having one end bearing against the top surface of said shield and an opposite end extending to the top surface of said drill bit, said rod being displaced by said shield so that said top end of said rod engages said driver to rotate said driver and couple said drill bit for rotation thereof and to disengage said driver from said drill bit when said shield is retracted upon sensing a void of bone in the drill passage during the drilling operation.

Claim 35

A surgical perforator for drilling a hole in a bone structure as claimed in claim 30 wherein said clutch means includes a plug and a spring urging said plug toward said drill bit mounted in a recess formed in said driver and said plug having a larger diameter than the diameter of said vertical passage so that said plug slides over the top surface of said drill bit.

Claim 36

A surgical perforator for drilling a hole in a bone structure as claimed in claim 31 wherein said drill bit includes a horizontal slot formed in said wall adjacent to said shield to provide a predetermined gap to allow the automatic displacement of said shield when the resistive load is applied and ceases.

Claim 37

A surgical perforator for drilling a hole in a bone structure as claimed in claim 32 including a vertical slot formed in said wall between said cutting edge and said shield wherein said shield cooperates with said cutting edge to permit exposure of said cutting edge when a predetermined resistive load is applied thereto.

Claim 38

A surgical perforator for drilling a hole in a bone structure as claim 33 including slots cut into said wall to form said cutting edge.

Claim 39

A surgical perforator for drilling a hole in a bone structure as claimed in claim 34 wherein said wall means defines the width of the cut in said bone structure wherein a plug of said bone remains after said cutting operation is completed.

Claim 40

A surgical perforator for drilling a hole in a bone structure as claimed in claim 29 including means for preventing said perforator from penetrating into said drilled passage a predetermined amount after said drill bit ceases cutting.

Claim 41

A surgical perforator for drilling a hole in a bone structure as claimed in claim 36 wherein said drill bit includes a central axis, said means for preventing penetration includes a threaded screw having an elongated shank threaded at the proximal and distal ends and coaxially disposed relative to said central axis and extending through said drill bit, a center driver threadably supported to said threaded screw at the distal end and having a bottom surface formed with a knurled surface adapted to engage the surface of the bone structure and a centrally disposed guide pin extending from the end of said threaded screw and adapted to penetrate said bone structure, stop pins, a bridge extending through diametrically disposed vertical slots formed in said wall for supporting said stop pins externally of said drill bit, said bridge being supported for rotary motion to said threaded screw between said threaded portions on the distal and proximal end of said threaded screw, and latch means to permit said threaded screw to be positioned by rotating through fixed threads or by rectilinear movement, spring means acting on one end of said threaded to urge said threaded screw to a deployed position, wherein when said threaded screw is in said deployed position said guide pin and knurled surface engage said bone structure to be maintained in a nonrotating condition and said stop pins rotate with said drill bit and moves with said threaded screw to maintain a predetermined distance from the surface of said bone structure as said drill bit penetrates the bone structure, and said threaded screw rotates with said drill bit when said resistive load ceases whereby further penetration of said drill bit will place said stop pins to bear against said bone structure and prevent further penetration of said drill bit.

Claim 42

A surgical perforator for drilling a hole in a bone structure as claimed in claim 37 including a latch mechanism having a main body extending through a lateral bore formed in said wall, a straight through passage parallel to said central axis formed in said main body, a portion of said straight through passage having threads formed therein and complementing the threads of said threaded screw and releasable spring means biasing said threads into engagement and the end of said main body being accessible to urge said main body in a direction to disengage said threads, whereby said threaded screw is permitted to be positioned longitudinally by said spring means on the top of said screw.

Claim 43

A surgical perforator for drilling a hole in a bone structure as claimed in claim 38 including a shoulder formed between said distal and proximal threaded portions of said threaded screw and said center driver bearing against said shoulder.