Rotary Cutting Tool

1. Field of the Invention

The present invention relates to a rotary cutting tool having a finitely adjustable and replaceable cutting insert. The tool described herein is in the form of a reamer but other uses will be readily apparent to those skilled in the art.

2. Description of the Prior Art

Rotary cutting tools having cutting inserts which are adjustable and replaceable are known in the art. Examples are described in U.S. Pat. Nos. 4,125,342 and 4,279,550. It is desirable to provide an improved rotary cutting tool of the type described in these patents. To this end it is desired to provide a rotary cutting tool wherein a pair of guide pads are spaced a sufficient degree to provide a tool having improved stability during use. It is also desirable to provide such a tool wherein various structural features are positioned to provide ease of manufacture and convenience of insert adjustment. It is further desirable to provide such a tool wherein finite radial adjustment of the cutting insert is possible. It is also desirable to provide such a tool wherein there is an improved clamping of the cutting insert.

The invention achieves these and other results by providing a rotary cutting tool comprising a holder which is elongated and generally cylindrical and to which can be attached a cutting insert. The holder includes a longitudinal axis and when viewed in axial cross section includes a vertical axis perpendicular to a horizontal axis. One end of the holder includes a recessed area including a first surface formed by the removal of a segment of the holder generally defined in axial cross section by an arc and chord of the holder. A first recess extends in an axial direction and into the holder from the periphery thereof. When viewing the holder in axial cross section the first recess is located at a first radius of the holder which is coincident with the vertical axis. A second recess extends in an axial direction and into the holder from the periphery thereof. When viewing the holder in axial cross section the second recess is located at a second radius of the holder which forms a first angle with the first radius. A first threaded aperture extends into the holder from the first surface along a first axis which is spaced from and parallel to the horizontal axis. A second threaded aperture extends into the holder from the first surface along a second axis which is spaced in an axial direction from the first axis and spaced from and parallel to the horizontal axis and the first axis. A third threaded aperture extends into the holder along a third axis which is parallel to the first and second axis. A third recess extends into the holder from the periphery thereof along a fourth axis which forms a second angle with the vertical axis and which is spaced about 180.degree. C. from the first radius. A first guide pad is positioned within the first recess and includes a first guide surface extending therefrom. The first guide pad includes a first vertical axis which is coincident with the first radius. A second guide pad is positioned within the second recess and includes a second guide surface extending therefrom. The second guide pad includes a second vertical axis which is coincident with the second radius. A first adjusting screw is threaded into the first threaded aperture and includes a first camming surface for engaging a corresponding camming surface of the cutting insert. A second adjusting screw is threaded into the second threaded aperture and includes a second camming surface for engaging such corresponding camming surface of the cutting insert. A clamping screw is threaded into the third threaded aperture. Means is attached to the elongated holder by the clamping screw for holding the cutting insert within the third recess such that a cutting edge of the cutting insert will extend along a third axis which is parallel to the longitudinal axis of the holder and is spaced about 180.degree. C. from the first radius.

FIG. 1 is a side elevation view of one embodiment of the present invention;

FIG. 2 is a sectional view of FIG. 1 taken along lines 2--2;

FIG. 3 is a sectional view of FIG. 1 taken along lines 3--3;

FIG. 4 is an enlarged side elevation view of the embodiment of FIG. 1 with various structural features removed for clarity;

FIG. 5 is a side view of a clamping member of the present invention;

FIG. 6 is a plan view of FIG. 5;

FIG. 7 is an elevation view of a cutting insert for use with the present invention; and,

FIG. 8 is a diagrammatic view of an adjusting screw of the present invention.

The embodiment which is illustrated in the drawings is particularly suited for achieving the objects of this invention. FIGS. 1 to 4 depict a rotary cutting tool 2 comprising a holder 4 which is in the form of an elongated and generally cylindrical tool shank having a longitudinal axis 6. When viewed in axial cross section as in FIGS. 2 and 3, the holder 4 includes a vertical axis 8 which is perpendicular to a horizontal axis 10, axes 8 and 10 intersecting at the longitudinal axis 6. One end 12 of the holder 4 includes a recessed area 14 including a first surface 16 formed by the removal of a segment of the holder 4 generally defined in axial cross section by an arc and chord of the holder.

A first recess 22 is provided extending in an axial direction. Recess 22 extends into the holder 4 from the periphery thereof. When viewing the holder in axial cross section as depicted in FIGS. 2 and 3, the first recess 22 is located at a first radius 24 of the holder which is coincident with the vertical axis 8. A second recess 26 is also provided extending in an axial direction. Second recess 26 extends into the holder 4 from the periphery thereof. When viewing the holder 4 in an axial cross section, the second recess is located at a second radius 28 of the holder which forms an angle 30 with the first radius 24. In the embodiment of FIGS. 1 to 4, angle 30 is about 145.degree. C.

A first threaded aperture 32 is provided extending into holder 4 from the surface 16 along a first axis 34 which is spaced from and parallel to the horizontal axis 10 as depicted in FIG. 4. In a like manner, a second threaded aperture 36 is provided extending into holder 4 from the surface 16 along a second axis 40 which is spaced in an axial direction from the first axis 34 as depicted in FIG. 4. Second axis 40 is also spaced from and parallel to horizontal axis 10 and first axis 34. A third threaded aperture 42 is provided extending into holder 4 along a third axis 44 which is parallel to the first axis 34 and second axis 40.

A third recess 46 is provided extending into holder 4 from the periphery thereof along a fourth axis 48 which forms a second angle 50 with the vertical axis 8 and which is spaced about 180.degree. C. from the first radius 24. When the cutting insert 52 of FIG. 7 is attached to the holder 4 as described herein, the horizontal axis 48' of the insert 52 will be coincident with axis 48.

A first guide pad 54 is positioned within the first recess 22. First guide pad 54 includes a first guide surface 56 which extends from recess 22 and also includes a first vertical axis 58 which is coincident with the first radius 24. A similar second guide pad 60 is positioned within the second recess 26. Second guide pad 60 includes a second guide surface 62 which extends from recess 26 and also includes a second vertical axis 64 which is coincident with the second radius 28. In the embodiment of FIGS. 1 to 4 the pads 54 and 60 are spaced an amount identified as angle 30 which is about 145.degree. C. Such spacing contributes to improved stability during use of the tool compared to other known prior art where pad spacing is closer together.

A first adjusting screw 66 of the type depicted in FIG. 8 is threaded into the first threaded aperture 32. Screw 66 includes a camming surface 68 for engaging a corresponding camming surface 70 of the cutting insert 52. A similar second adjusting screw 72 is threaded into the second threaded aperture 36. Screw 72 includes a camming surface (not shown), similar to camming surface 68, for engaging camming surface 70 of the cutting insert 52.

In addition to the adjusting screws 66 and 72, a clamping screw 74 is threaded into the third threaded aperture 42. Means is attached to the elongated holder by the clamping screw 74 for holding the cutting insert 52 within the third recess 46 such that a cutting edge 76 of the insert will (a) extend along a third axis 78 which is parallel to the longitudinal axis 6; and, (b) be spaced about 180.degree. C. from the first radius 24. Axis 78 is superimposed upon insert 52 in FIG. 7. In viewing FIGS. 2 and 3, axis 78 extends perpendicular to the plane of the paper upon which FIGS. 2 and 3 are drawn.

In the preferred embodiment the rotary cutting tool includes a fourth recess 80 which extends into the holder 4 from the first surface 16 along the third axis 44 to a second surface 82. A third surface 84 extends from the second surface 82 to the first surface 16. In such embodiment, the third threaded aperture 42 extends into the holder from the second surface 82. In the embodiment of FIGS. 1 to 4, the holding means includes a clamping member 86 which fits into the fourth recess 80. Referring to FIGS. 5 and 6, the clamping member 86 includes a fourth surface 88 which engages the third surface 84 of the holder for sliding movement relative thereto. Clamping member 86 includes a lip 90 which includes a fifth surface 92 which will engage and be parallel to an upper surface 94 of the cutting insert 52, upper surface 94 being adjacent the camming surface 70. The clamping member 86 includes a fourth threaded aperture 96 extending therethrough and parallel to the fourth surface 88. Aperture 96 has a fifth axis 98 which is coincident with the third axis 44.

In the preferred embodiment, the clamping screw 74 is threaded in a first direction at one end 100 which is threaded into the third threaded aperture 42 and is threaded in an opposite second direction at an opposite end 102 which is threaded into the fourth threaded aperture 96. As depicted in FIG. 4, the third axis 44 can be located between the first axis 34 and the second axis 40 when viewed in the horizontal direction. In addition, the third axis 44 is depicted in FIG. 1 as being intermediate of, on the one hand, the first axis 34 and second axis 40, and on the other hand the horizontal axis 6, when viewed in the vertical direction.

In the preferred embodiment the third recess 46 includes a cutting insert support surface 104 which is parallel to the fifth surface 92 of the clamping member 86 and the upper surface 94 of the insert 52.

In the embodiment of FIGS. 1 to 4 the holder 4 includes a first bore 106 extending along the longitudinal axis 6 from an end 108 opposite of end 12 to a position generally designated 110 in the vicinity of the recessed area 14. A first channel 112 is provided at the periphery of the holder 4 in the vicinity of the first recess 22. A second channel 114 is provided at the periphery of the holder extending into the recessed area 14. A second bore 116 extends from the first bore 106 to the first channel 112 and a third bore 118 extends from the first bore 106 to the second channel 114. During use of the rotary cutting tool a fluid such as water is caused to flow through bore 106, then through bores 116 and 118, and along channels 112 and 114. The channels 112 and 114 include a cover plate 120 and 122, respectively, to divert the fluid along each respective channel.

In order to mount a cutting insert 52 to a holder 4, the clamping screw 74 is loosened to loosen the clamping member 86. Insert 52 is then inserted into recess 46 such that the insert rests upon surface 104 and the camming surface 70 engages the camming surfaces 68 of the adjusting screws 66 and 72. When in this portion, the clamping screw 74 is tightened to tighten the clamping member 86 such that the surface 92 of the clamping member firmly engages the upper surface 94 of the insert. Outward radial adjustment of the insert can be effected by screwing the adjusting screws 66 and 72 inward to the extent desired to cause the surfaces 68 of the adjusting screws to effect a camming action against the surface 70 of the insert to move the insert in a radial direction outward. The insert can be moved radially inward by screwing the adjusting screws 66 and 72 outward to the extent desired to cause the surfaces 68 to disengage the surface 70 of the insert. The insert can then be pushed inward by hand until the surface 70 of the insert once again engages the surfaces 68 of the adjusting screws 66 and 72. In such structure, the axes of the clamping screw and adjusting screws are parallel to each other and to a horizontal axis of the holder. Such structure provides ease of manufacture and convenience of insert adjustment. In addition, by providing adjusting screws which are screwed generally inwards towards the insert top surface 94 to cause outward radial movement, the engagement of the camming surfaces of the adjusting screws with the camming surface of the insert contribute to firmly holding the insert in place. In a preferred embodiment of FIG. 8, an adjusting screw is depicted superimposed upon an axis 34 or 40, as the case may be. In such embodiment the camming surface 68 extends at an angle 124 of 14.degree. C. relative to the axis 34 or 40. In this embodiment minute radial adjustment can be effected in that small incremental radial movements within the dimension generally designated 126 can be effected through a much larger axial movement generally designated 128. In particular, in such embodiment, the radial adjustment 126 is equal to 1/4 of the axial adjustment 128 which provides for very finite adjustment.

The embodiments which have been described herein are but some of several which utilize this invention and are set forth here by way of illustration but not of limitation. It is apparent that many other embodiments which will be readily apparent to those skilled in the art may be made without departing materially from the spirit and scope of this invention.