US 2822008 A
Description (OCR text may contain errors)
Feb. 4, 1958 G. J. SCHAEFER 2,822,008
ROTARY GROOVING CUTTER TOOL Filed Feb. 25, 1957 mmvrok GEORGE J SCH/45:5?-
\ ATTOAIYfX United States Patent ROTARY GROOVING CUTTER TOOL George J. Schaefer, Beatrice, Nebr., assignor to F. D.
Kees Manufacturing Company, Beatrice, Nebr., a corporation of Nebraska Application February 25, 1957, Serial No. 642,158
1 Claim. (Cl; 144-219) This invention is concerned with a rotary grooving tool and more particularly one adapted to cut circular grooves in wood or the like in which the cutter knives of a single form are mounted in an alternating relation.
Various types of rotary groove cutters have been pro posed and many are in commercial use. But there is still a need for a high production tool which will make a clean cut groove over an extended period of time with a minimum of resharpening and maintenance. It is further desirable that the knives be of such nature that a single form can be uniformly and quickly resharpened and replaced on the tool head without complicated readjustments and positioning being required.
It is therefore a primary object of my invention to provide a grooving tool and cutting knife capable of cleanly cutting the inside and outside walls of a groove, depending only on the positioning of the knife blade in inside or outside relationship to the tool head.
It is a further object of my invention to provide a grooving tool in which the trailing edges of the knife blades are canted to one side to prevent burning.
Yet another object of my invention is to provide a grooving tool in which the knives can be mounted in such a manner as to position the cutting points alternately to provide leading and trailing edges in relation to the direction of rotation.
It is still another object of my invention to provide a grooving tool in which a raker tooth may be circumferentially aligned with the cutting teeth.
Other and further features and objects of the invention will be more apparent to those'skilled in the art upon a consideration of the accompanying drawings and'following specifications, wherein is disclosed a single exemplary embodiment of the invention, with the understanding, however, that such changes may be made therein as fall within the scope of the appended claim, without departin g from the spirit of the invention.
In said drawings:
Figure l is a view in perspective showing a rotary grooving tool constructed according to my invention.
Figure 2 is a top view of the device shown in Figure 1, the radial position of the knives being particularly shown.
Figure 3 is a partial view in section taken on line 3-3 of Figure 1.
Figure 4 is a front view of an individual knife cutter mounted on such as the device shown in Figures 1 and 2.
Figure 5 is a side view of the knife shown in Figure 4.
Figure 6 is a view in perspective of the single raker tooth which may be mounted on the device shown in Figures 1 and 2.
Figure 7 is a view of the form of cut made by the device as illustrated in Figure 1, and
Figure 8 is a view in cross section of a groove made by a device such as is shown in Figures 1 and 2 when the raker tooth, shown in Figure 6, is incorporated therewith.
Referring now to the drawings, and particularly to Figure 1; the main body 11 of the tool is a circular disc of substantial thickness having a center opening 12 therein and an extended bore 13 in the side wall of the circular disc. This opening is provided to attach the tool to the arbor of any conventional drill, either portable or stationary. A set screw 14 may be used to firmly secure the circular disc or head to the arbor.
Referring now to Figure 2, which is a top View of the tool, the cutter head has a series of four rectangular slots shown at 15, 16, 17 and 18 about the outer circumference thereof. These four slots are parallel to the axis of the opening 12. It will be noted that the tool is adapted to rotate in a clockwise direction. The inner portion of the slots are formed in such a manner as to provide two corner portions 19 and 20. These two corners are at a slightly different radial length from the center of the cutter head. The corner 19 is slightly closer to the center than the corner 20.
It will be apparent that when the knife blade, such as 21, is positioned in this slot, the inner forward vertical edge of the blade will be closer to the center of the cutting head than will be the vertical trailing edge. This mounting is of considerable importance and will be discussed at greater detail in reference to the knives themselves.
Referring again to the cutter head, as shown in Figure 1 and Figure 2, the knife blades such as 21, 22, 23 and 24 are mounted in the previously mentioned slots such as 17. The knives are held in position by set screws 25, 26, 27 and 28 which extend inwardly into drilled and tapped openings in the cutter head. Each mounting assembly also includes a shim, such as 29, which is positioned in the slot between the inner face thereof and the knife blade. Of course the shims may be of differing sizes to cause the knife blade to be positioned inwardly or outwardly, as desired, to secure slightly varying sizes of cuts.
Now referring to the knife blade, such as is shown in Figure 4, the main body of the blade 21 is formed of a piece of rectangular cutting steel, the original blank being considerably longer than it is wide. In the upper portion of this blank is an elongated slot 30. The lower portion of the blade is adapted to perform the cutting operation. This portion of the blade is slanted, as at 31, diagonally across the width of the knife. A second diagonal cut 32 is provided to cause this face to be angular in relation to the thickness of the blade, the cutting portions of the blade being the point 33 and the sharpened angular edge 34 and the lower portion of the vertical edge 32a.
It will be apparent that this knife blade may be mounted in the cutting head with either side of the blade towards the face of the slots. For example, if the side 34 is towards the slot and the direction of movement of the head clockwise, then the point 33 and edge 32a will cut one portion of the groove, this being the inside wall. As the cutter head is moved downwardly this point will make successive cuts in the wall portion of the groove as well as in the base, and thereby provide a smooth vertical surface in the groove.
If, on the other hand, the cutter is mounted in a reverse position with the wall 36 towards the inner side of the tool, the cutting edge 34 and the point 33 will cut the outer wall of the groove. Obviously when the cutters are mounted in the head, they will be alternately positioned about the circumference of the head whereby one cutter will cut the inside wall, whereas the cutter mounted immediately behind it will cut the outside walls of the groove. In practice, as the tool is forced downwardly into the wood being cut, a groove, such as is shown in Figure 8, will be formed with an upwardly extending triangular projection 37 in the bottom thereof.
If a flat bottomed groove, such as is shown in Figure 7, is desired, the raker tooth shown in Figure 6 may be Patented Feb. 4, 1958 3 inserted inthe cutter head in place of one of the angular knives. In practice, it has been found preferable to substitute this raker tooth for one of the outside Wall cutting knives. The taker toothis a blanktsimilar towthati employed in. forming; the, knives, .the =main ".PQI'tiODnOI" body being the. rectangular :flat stee1=p0rti0n 38,- the lower d. of the; knife being cut angularly asat 39, the face; ofthe .cutjbeing-atright angles to the'walls of the blank. and thusqa straight cuttingpoint 40being formed. This.
point 40 will cut the flat base portion such as 41 of Figure 7.
I will now describe .in-.-detail.- the cooperative action of tthe.alternatelypositioned knives by virtue of the radially.angularpositionof the inner. wall ofthe slots,--as previously described... It will beapparent that in practice, a groove iscut which is .of greater width than the width of .the knife bladesthernselvem Referring back toFigure l, a comparisonof the blades 21 and 24 will showthe efiect' of this mounting.
Assuming that the knife 24 has been .mounted in such a manner that the point 33 is in line with the corner;20:
but outwardly therefrom, the thickness of the blade, the leadingedge 32a. and'point 33 are at the greatest radial distance from the'center of the head. This results'in the edge 341s angularin relation inwardly from the walland cut-being made by thepoint and the trailing and knife therefore does not touch it, thereby preventing any burnishing action.
The next knife 21 is positioned with the point 33 at the closest radial distance in relation to the center ofthe head corresponding to the corner 19 of slot 17. However, in this case the angular cutting edge 34 is presented to theinner' wall of-- the cut or groove and all other edgesheld away from the walls of the cut. It is also to be noted that byreason of this alternate positioning.
mounted on this device, may be cut in an identical manner.
They may then be positioned in the slots and held firmly bythe set-screws. When the head is rotated, even. though the blades are in alternate positions, only the cutting edges arepresented to the work piece. All the trailing; edges are positioned insuch .a mannerflasrtobe. awayiromthe.
walls of the cut and all burnishing and burning thus avoided. Of course it will also be apparent that the knives may be inserted in the cutter in such a manner as not to be in exactly the same vertical position in such a manner that they will not cut.to..exactly the same depth. However, such misalignment will not affect the operation of the device or materially alter the'nature of the. grooves being cut.
It will also beapparent that the boss 42 will'limit the downward movement of the cutter head and the-knives can be positioned in relation to this boss to limit the depth of the. groove CllliltO the approximate dimension-required for satisfactory sealing of the retaining ring.
Although I have described a specific embodiment of my invention, it is apparent that modifications thereof may be made by those skilled in the art. Such modifications may be made;without.departing from the spirit and scope-lot my inventionxas set forth'lin' the appended claim.
I claimas. my. invention z Inia groovingtool of the.type described, a cylindrical head: portionr'havingwa pluralityof-vertical rectangular slots therein, said:slots being. sozpositioned in relation to the head portion that onetcorner thereof shall be at a greatenradiakdistance fromthe center. point of said head thanLthe.oppositecorner, a plurality ofknives adapted .to be positionedin.said=vertical slotg-said knives having a slotted portion therein; a .set tscrew'adapted v.to affix said slottedportion..onxsaiduheadt whereby. said. knife may be vertically positioned in relation to said head, said knives further having, .a bi-angular...cutting portionion the lower endtthereofto .provide'ca downwardly depending cutter' point whereby said 'knives maybe alternately positioned in said headwith 'referenceto the'angularcut'thereof to. secure a cutting path of greateri.Width..than:thickness of' saichknives by reasonxofthe angulanformation of said slots. I
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