Drill bushing

Claim 2

A drill bushing having an integral, sleevelike cylindrical body defining a longitudinal axis, the inside and outside cylindrical surfaces of said sleeve being precision formed to accurately guide a rotary tool for axial motion therein, said body having a forward end face generally transverse to its axis, a series of circumferentially spaced chip breaking notches in said end face adapted to break chips moving rearwardly relative to the bushing, said notches each being defined by first and second surfaces extending from the inside to the outside cylindrical sleeve surfaces, the first surface of each notch lying in a plane parallel to said axis, the second surface of each notch lying in a plane obliquely transverse to said axis, said first and second surfaces intersecting at a line spaced from said end face, a plurality of flow passages in the body for directing separate streams of liquid against a tool in the body forwardly of said end face whereby said chips are forced laterally away from said tool and eventually into said chip breaking surfaces.

Claim 3

A drill bushing as set forth in claim 1, wherein said flow passages are circumferentially arranged on said body intermediate said chip breaking surfaces.

Claim 4

A drill bushing as set forth in claim 2, wherein said flow passages each comprise a hole in the cylindrical wall of the body, said holes extending axially from said forward end face.

Claim 5

A drill bushing as set forth in claim 3, wherein said holes are convergent with the axis of the body and communicate with the outside surface of the body at a zone midway along the length of the bushing.

Claim 6

A drill bushing as set forth in claim 4, wherein said holes are drilled at an angle substantially in the range between 7* and 10* relative to the axis of said bushing.

Claim 7

A drill bushing as set forth in claim 4, wherein said bushing forms an assembly with an outer cylindrical sleevelike liner, said liner having precision formed, inside and outside cylindrical surfaces, the diameter of said inner surface being substantially equal to the outer diameter of said bushing, said liner having fluid channel means for supplying liquid to said bushing holes.

Claim 8

A drill bushing as set forth in claim 6, wherein said bushing body is nominally longer than said liner, whereby said forward bushing end face is adapted to extend axially forward of said liner when said liner is fully engaged with said bushing.

Claim 9

A drill bushing as set forth in claim 3, wherein said flow passage holes are spaced radially inward at said end face from the outer cylindrical surface of said bushing.

Claim 12

A drill bushing assembly comprising a cylindrical sleevelike bushing having a longitudinal axis and forward and rearward end faces, means on one of said end faces for locking said bushing against rotation in a jig plate, said forward end face lying in a plane transverse to the axis of the bushing, a plurality of circumferentially spaced drilled passages extending from said forward end face through the wall of the bushing to ports on the outer cylindrical surface of the bushing midway along its length, the passages converging towards the axis of the bushing at a zone forward of said end face, said passages being spaced away from said outer cylindrical surface at said forward end face, a series of chip breaking notches extending across the forward end face of the bushing from its inner cylindrical surface to its outer cylindrical surface, said notches intervening and being spaced from said passages, said chip breaking notches including chip shearing surface portions lying in substantially radial planes parallel to said axis, said notches also including chip clearance surface portions lying in planes obliquely transverse to said axis and intersecting said parallel planes, a cylindrical sleevelike liner on the outer cylindrical surface of the bushing, said liner having an inner cylindrical surface dimensioned to form a substantially fluid-tight seal on said outer bushing surface, said liner including an internal annulus communicating with each of said ports, a radial passage extending from the outer cylindrical surface of the liner to said annulus and adapted to supply liquid to the annulus and said ports, said liner being somewhat shorter in length than said bushing, whereby the bushing is adapted to be supported by the full length of the liner with its forward end face being disposed a normal distance from the liner to provide chip clearance between the assembly and a workpiece.

Claim 13

A drill bushing assembly comprising a cylindrical sleevelike bushing having a longitudinal axis and forward and rearward end faces, means on one of said end faces for locking said bushing against rotation in a jig plate, said forward end face lying in a plane transverse to the axis of the bushing, a plurality of circumferentially spaced drilled passages extending from said forward end face through the wall of the bushing to ports on the outer cylindrical surface of the bushing midway along its length, the passages converging towards the axis of the bushing at a zone forward of said end face, said passages being spaced away from said outer cylindrical surface at said forward end face, a series of chip breaking notches extending across the forward end face of the bushing from its inner cylindrical surface to its outer cylindrical surface, said notches intervening and being spaced from said passages, said chip breaking notches including chip shearing surface portions lying in substantially radial planes parallel to said axis, said notches also including chip clearance surface portions lying in planes obliquely transverse to said axis and intersecting said parallel planes, a cylindrical sleevelike liner on the outer cylindrical surface of the bushing, said liner having an inner cylindrical surface dimensioned to form a substantially fluid-tight seal on said outer bushing surface, said liner including an internal annulus communicating with each of said ports, a radial passage extending from the outer cylindrical surface of the liner to said annulus and adapted to supply liquid to the annulus and said ports, said liner being somewhat shorter in length than said bushing, whereby the bushing is adapted to be supported by the full length of the liner with its forward end face being disposed a normal distance from the liner to provide chip clearance between the assembly and a workpiece.

Claim 14

A drill bushing assembly comprising an inner cylindrical bushing member and an outer cylindrical sleevelike liner member each concentric with a common longitudinal axis, said bushing having a plurality of passages for directing liquid streams on a rotary tool extending through the bushing in a zone forward of the bushing, said passages being circumferentially spaced in the wall of the bushing, each of said passages extending from a hole in a forward end face of the bushing axially rearwardly and radially outwardly at an angle substantially in the range of 7* to 10* with the axis of the bushing, each of said passages terminating at a port on an outer surface of the bushing midway along its length, said outer liner having a bore forming a substantially fluid-tight fit with corresponding outer surfaces of sid bushing, an annular groove formed by one of said members, said groove being axially sealed by said fit between said members and in communication with said ports, said liner having a radial hole extending through its wall into communication with said groove, said bushing being a nominal size longer than said liner whereby said forward bushing end face is adapted to extend axially beyond said liner when the rearward ends of said members are aligned, said bushing member having chip breaking notches on said bushing end face intermediate said passage Holes, each of said notches being defined by first and second surfaces extending between the inner surface to the outer surface of the bushing member each of said first surfaces lying in a plane parallel to said axis, and each of said second surfaces lying in a plane obliquely transverse to said axis and intersecting the respective parallel plane of the first surface.

Claim 15

A drill bushing assembly comprising an inner cylindrical bushing member and an outer cylindrical sleevelike liner member each concentric with a common longitudinal axis, said bushing having a plurality of passages for directing liquid streams on a rotary tool extending through the bushing in a zone forward of the bushing, said passages being circumferentially spaced in the wall of the bushing, each of said passages extending from a hole in a forward end face of the bushing axially rearwardly and radially outwardly at an angle substantially in the range of 7* to 10* with the axis of the bushing, each of said passages terminating at a port on an outer surface of the bushing midway along its length, said outer liner having a bore forming a substantially fluid-tight fit with corresponding outer surfaces of sid bushing, an annular groove formed by one of said members, said groove being axially sealed by said fit between said members and in communication with said ports, said liner having a radial hole extending through its wall into communication with said groove, said bushing being a nominal size longer than said liner whereby said forward bushing end face is adapted to extend axially beyond said liner when the rearward ends of said members are aligned, said bushing member having chip breaking notches on said bushing end face intermediate said passage Holes, each of said notches being defined by first and second surfaces extending between the inner surface to the outer surface of the bushing member each of said first surfaces lying in a plane parallel to said axis, and each of said second surfaces lying in a plane obliquely transverse to said axis and intersecting the respective parallel plane of the first surface.