초록 ▼

A screw driving device is provided which can counter-sink a screw at angles off of normal from a workpiece. The device includes a shank held in contact with a screw bit to drive the tip when a plurality of balls are held in contact between a screw bit head and a sleeve surrounding the shank and to d

A screw driving device is provided which can counter-sink a screw at angles off of normal from a workpiece. The device includes a shank held in contact with a screw bit to drive the tip when a plurality of balls are held in contact between a screw bit head and a sleeve surrounding the shank and to disengage the shank from the bit when the screw is at a desired counter-sunk depth. The disengagement of the shank from the screw bit is provided by permitting the plurality of balls to slide out of contact between the rotating shank and bit to thus disengage the shank from the screw bit.

대표청구항 ▼

The invention claimed is: 1. A device for driving screws comprising: a shank having an end portion defined by a wall of annular cross-section defining a seat, said end portion terminating at an end surface, a plurality of radial bores formed in said wall; a screw bit having a head end received in s

The invention claimed is: 1. A device for driving screws comprising: a shank having an end portion defined by a wall of annular cross-section defining a seat, said end portion terminating at an end surface, a plurality of radial bores formed in said wall; a screw bit having a head end received in said seat and a driver end adapted to drive a screw; a sleeve surrounding at least part of said end portion of said shank and axially movable, relative to said shank, said sleeve having a surface facing said shank with a plurality of recesses, said sleeve having a bottom surface with an aperture through which said screwdriver bit is disposed; a spring disposed between said end portion of said shank and said bottom of said sleeve to provide a biasing force between said shank and said sleeve, wherein said spring is disposed between said end surface of said shank and said bottom portion of said sleeve; and a plurality of balls disposed in respective bores in said end portion of said shank, said balls held in engagement with said screw bit head when said balls are in contact with a non-recess portion of said sleeve, said balls movable in a radial direction away from said screwdriver bit head into said recesses when said balls align with said recess, thereby disengaging contact with said screw bit head. 2. The device of claim 1, wherein the radius of said sleeve at said bottom is no greater than 8 mm. 3. The device of claim 1, wherein the radius of said sleeve at said bottom is sufficiently small to permit said device to countersink a screw in a workpiece when said device is at an angle of at least 7.8�� off normal from a surface of said workpiece. 4. The device of claim 1, wherein the radius of said sleeve at said bottom is sufficiently small to permit said device to countersink a screw in a workpiece when said device is at an angle greater than 6.3�� off normal from a surface of said workpiece. 5. The device of claim 1, wherein said spring comprises a coil spring encircling at least a portion of said bit. 6. The device of claim 1, wherein the spring is disposed between said end surface of said shank and an inner bottom surface of said sleeve. 7. The device of claim 1, wherein the spring is operatively associated with the end portion of the shank which is proximate the end surface. 8. The device of claim 1, wherein the spring is operatively associated with the end surface of the shank. 9. The device of claim 1, wherein the spring has an outside radius no greater than an outside radius of the shank. 10. A device for driving screws comprising: a shank having an end portion defined by a wall of annular cross-section defining a seat, said end portion terminating at an end surface, a plurality of radial bores formed in said wall; a screw bit having a head end received in said seat and a driver end adapted to drive a screw; a sleeve surrounding at least part of said end portion of said shank and axially movable, relative to said shank, said sleeve having a surface facing said shank with a plurality of recesses, said sleeve having a bottom surface with an aperture through which said screwdriver bit is disposed; a spring disposed between said end portion of said shank and said bottom of said sleeve to provide a biasing force between said shank and said sleeve, wherein the spring is disposed between said end surface of said shank and an inner bottom surface of said sleeve; and a plurality of balls disposed in respective bores in said end portion of said shank, said balls held in engagement with said screw bit head when said balls are in contact with a non-recess portion of said sleeve, said balls movable in a radial direction away from said screwdriver bit head into said recesses when said balls align with said recess, thereby disengaging contact with said screw bit head. 11. A device for driving screws comprising: a shank having an end portion defined by a wall of annular cross-section defining a seat, said end portion terminating at an end surface, a plurality of radial bores formed in said wall; a screw bit having a head end received in said seat and a driver end adapted to drive a screw; a sleeve surrounding at least part of said end portion of said shank and axially movable, relative to said shank, said sleeve having a surface facing said shank with a plurality of recesses, said sleeve having a bottom surface with an aperture through which said screwdriver bit is disposed; a spring disposed between said end portion of said shank and said bottom of said sleeve to provide a biasing force between said shank and said sleeve, wherein the spring has an outside radius no greater than an outside radius of the shank; and a plurality of balls disposed in respective bores in said end portion of said shank, said balls held in engagement with said screw bit head when said balls are in contact with a non-recess portion of said sleeve, said balls movable in a radial direction away from said screwdriver bit head into said recesses when said balls align with said recess, thereby disengaging contact with said screw bit head.