US 2744451 A
Description (OCR text may contain errors)
May 8, 1956 Filed Feb. 28, 1952 L. E. LEE
PARTING AND SLOTTING TOOL 3 Sheets-Sheet 1 INVENTOR LUTHER E. LEE
f/ZQQM QBWW ATTORNEYS May 8, 1956 5, LEE 2,744,451
PARTING AND SLOTTING TOOL Filed Feb. 28, 1952 3 Sheets-Sheet 2 FIG. 2
' 4s 45 42 40 y. I 5/ Fla 4 INVENTOR LUTHER E. LEE
JZAQQQM (Q13 WW ATTORNEYS M y 1956 L. E. LEE
PARTING AND SLOTTING TOOL Filed Feb. 28, 1952 INVENTOR LUTHER E. LEE M693; S /2 4am ATTORNEYS PARTING AND SLOTTING TOOL Luther E. Lee, Takoma Park, Md. Application February 28, 1952, Serial No. 274,040
Claims. (Cl. 90-33) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used byor for the Government of the United States of America for governmental purposes without the payment of royalties thereon or therefor.
This invention relates to cutting tools and more particularly to a parting and slotting tool for finishing a material to close tolerances in a single operation.
In the past when cutting large billets of metal from the common stock it has been found necessary to perform a number of finishing operations upon the billet after initially separating it from the stock in order to reduce the dimensions of the billet to predetermined tolerances. These finishing operations were made necessary by the practice of allowing as much as .25 inch in the dimensions for error resulting from crooked or leaning cuts made by tools of the prior art in the initial slotting operation. The crooked or leaning cuts developed after the tool cutter bit had penetrated a surface of the stock and were usually caused on a return stroke by the cutter bit contacting the side walls of the groove being out which contact caused one edge of the cutter bit to wear faster than the other; or by chips which remain in the groove after a cutting stroke which caused the tool to jump on a return stroke and thus gouge or score the side walls of the groove. The dulling of the cutter bit on one side thereof had a cumulative afi'ect on the cutting or grooving operation, for on a cutting stroke the sharp edge of the bit would cut deeper than the dull edge thus causing the cutter carrying tool to swing over from a predetermined course of travel to effect a slanting cut. Thereafter, on a return stroke the bit was forced against the side of the groove with greater pressure to further dull the cutting edge of the bit which in turn caused the tool to bear ofl. further on the following cutting stroke to thereby increase the slant of the cut.
The present invention avoids the disadvantages of the prior art by providing a tool having a plurality of cutter bits mounted in tandem thereon. Each cutter bit machines a narrower groove than the succeeding cutter bit and a means is provided which automatically retracts the last cutter bit upon completion of a work stroke so as to permit the tool to clear the work on a return stroke. When this means is actuated to retract the last cutter bit, the first and last cutter bits are raised to a position corresponding to the portions of the groove cut by the second and last cutter bits respectively, thus the tool is returned through the groove without contacting the sides thereof. Upon completion of the return stroke the tool is lowered thereby positioning the cutters for a work stroke and means are simultaneously actuated to expand the last cutters to a cutting position.
With the foregoing in mind it is an object of this invention to provide a cutting and slotting tool in which the cutter bits are prevented from engaging a workpiece on v the return stroke of the tool.
Another object is the provision of a tool for accurately slotting a workpiece in a single operation.
Still another object is the provision of a tool for slot- States Patent 0 ting a workpiece to any desired depth which will not wedge in the slot or steer to one side.
A further object is the provision of a tool for making wide finishing cuts on surfaces without chattering or gouging into the work.
Still another object is the provision of an adjustable tool for cutting grooves of various widths.
Yet another object is to provide a tool for accurately machining deep slots in a workpiece.
Another object is the provision of an adjustable tool which will permit a machine to be operated at maximum speed on a return stroke.
Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Fig. 1 is a side perspective view from below of a cutting tool embodying the invention installed on a planer;
Fig. 2 is an enlarged side elevation of the cutting head of the tool showing the position of the parts during a forward cutting stroke;
' Fig. 3 is an enlarged horizontal view from above taken along a line substantially corresponding to line 3-3 of Fig. 2 and showing a bit spreading wedge in the forward or cutting position;
Fig. 4 is a change position view similar to Fig. 3 but wherein the wedge is shown partially withdrawn to retract the cutter bits so that they clear the work on the return stroke; 7
Fig. 5 is a front view of the cutting tool taken from a point substantially corresponding to line 5-5 of Fig. 2 showing the positions of the, cutter bits during a cutting stroke;
Fig. 6' is a change position view similar to Fig; 5 in showing the retracted positions of the cutter bits during a return stroke;
Fig. 7 is a rear perspective view of the forward cutter bit;
Fig. 8 is a front perspective view of the central cutter bit disclosing the knife edge which aids in clearing chips from the groove;
Fig. 9 is an exploded rear view of the after cutter bits and the holder therefor; and
Fig. 10 is an enlarged perspective view of the wedge which spreads the after cutter bits.
Referring now to the drawings wherein like reference numerals designate like parts throughout the several views and more particularly to Figs. 1 and 2 wherein there is disclosed a planer or similar machine 20 having a vertically adjustable. tool head 21 with a clapper box 22 mounted thereon upon which is attached, in any well known manner, a slotting and grooving cutter tool 23. The tool 23, which comprises the present invention; includes a base plate 24 on which is firmly secured a chatter-free goosenecked tool holding blade 25 having a provision at its lower end for mounting a plurality of cutter bits 26, 27; and 28.
The central cutter bit 26, which projects lowest, is mounted in an aperture in the underside of the blade 25 and is held in position by means of a set screw 29 and, as shown in detail in Fig. 8, has a sharp leading edge 30 which breaks up chips and shavings cut from the workpiece and prevents them from bunching between the central. cutter bit and the leading cutter bit 27 and thereby interfering with the operation of the device.
The leading cutter bit 27, having a configuration best illustrated in Fig. 7, is mounted in a cutout portion on the lower leading edge of blade 25 and held rigidly in place by means of a bolt or other similar means 31 and a key (Fig. 7) which fits within a mating keyway (not 3 shown) in the blade. The leading cutter bit 27 has a cutting edge that is wider than that of the central or first cutter bit 26 and is located at a point higher than that of the first cutter bit so that it does not begin to operate on a workpiece until after the first bit has cut a central groove.
The third or after cutter bits 28 are a pair of side cutters mounted on a bifurcated bit holder 35 shown in Fig. 9 and which is rigidly secured at its upper forward part to the back of the blade by means of a key 36 and bolts 37, 38, and 39. The holder has its lower end bifurcated to provide spaced bit carrying members or legs 40, each of which is slotted at 41, to receive a cutter bit 28, each of which is securely fastened therein by means of a bolt 42. The bifurcated legs 40, each carrying a cutter bit 23, are spread so as to separate the bits and cause them to engage the workpiece by means of a wedge shaped cam 45 which is moved relative to the bit holder 35 to engage cammed surfaces 46 on the legs and thus cause the legs to move outwardly against the natural resiliency of said legs.
The lateral movement of the after cutter bit 28 is eifeeted through a motion of the clapper box 22 relative to the machine 20 at the beginning and the end of a work stroke. The relative movement between the clapper box 22 and the machine is transmitted to the cutter bits 28 through a linkage system which includes an adjustable link arm 50 having one end thereof pivotally mounted on the machine tool head 21 and the other end pivotally secured to the rearwardly extending arm of a wedge cam carrying bcllcrank 51 which is pivoted as shown to the upper portion of the tool holder 35 and carries the wedge cam on the depending arm thereof. At the end of a work stroke the clapper box 22 pivots upwardly which causes the bcllcrank 51 to rotate counterclockwise to the position shown by dotted lines in Fig. 2 to partially withdraw the wedge cam 45 from between the bifurcated legs 40 and the resultant movement of the bifurcated legs moves the cutter bits 28 inwardly due to the resiliency of the legs. The clapper box 22 remains in a raised position until the work has returned to the start position, whereupon it swings downwardly thereby rotating the bcllcrank 51 clockwise and causing the wedge cam 45 to move the legs 40 outwardly along with the cutter bits 28 mounted thereon.
The width of the cut made by the after cutter bits 28 may be varied by adjusting the length of link arm through a threaded connection 52 to extend or shorten the arm and thus regulate the depth to which the wedge 45 is inserted between the cutter carrying members 40 and thereby determine the extent of the lateral movement of the cutter bits 28 and the width of groove or slot to be out.
A cutter bit lubricating and cooling system 55 is provided which may be of the free flowing gravity type as shown in Fig. l. The system 55 includes a lubricant-coolant container 56 having a liquid conducting tube 57 extending from a flow control petcock 58 attached to the bottom of the container and leading to a position from which the lubricant-coolant may be directed upon the leading cutter bit 27. If it should be desired to use the tool 23 for cutting or grooving the side of a workpiece then it may be expedient to modify the gravity flow system 55 to include a compressed air supply (not shown) to force the lubricant-coolant from the container and also blow the chips produced by the action of the leading cutter 27 from before the cutter.
Preparatory to operation, the tool 23 is mounted on the clapper box 22, and the finishing after cutter bits 28 are adjusted to a predetermined cutting width by turning the adjusting threaded connection 52 which shortens and lengthens the link arm 50 thereby causing the wedge 45 to move between the cutter bit carrying legs 40 and thus cause the cutter bits to move transverse to the direction of the work stroke. A workpiece 60 is then positioned on a bed plate 61 of the machine 20 and the tool 23 is aligned with the workpiece so that the cutting edges of the finishing after cutter bits 28 are equidistant from the center line of a proposed groove. Tool 23 is then lowered until the lead cutter bit 27 is at a predetermined distance above the workpiece 60 and the central cutter bit 26 adjusted to a position where it contacts the upper surface of the work and there locked in place by means of the set screw 29. Petcock 58 is opened to permit the flow of lubricant-coolant upon the lead cutter 27 and the machine 20 is then actuated to begin operations.
In operation the tool 23 moves relative to the workpiece 66 to cut a groove having a configuration best illustrated in Figs. 5 and 6. On the initial cutting or groov ing stroke the central cutter bit 26 alone contacts the workpiece 60 to cut a slot along the center line of the proposed groove and on subsequent work strokes the tool 23 is automatically fed downwardly a predetermined distance equal to or less than the depth of the slot cut by the central bit, then as each of the cutter bits 26, 27, and 28 is successively brought into contact with the work 60 it increases the width of the slot or groove cut by the preceding cutter or cutters.
Upon the conclusion of each cutting stroke, the clapper box 22 is pivoted upwardly and outwardly thus causing the cutter bits 26 and 27 to be raised to a position whereby on a return stroke they will pass through the grooves cut by cutter bits 27 and 28 respectively and the wedge 45 is partially withdrawn from between the legs 40 by the action of link arm 50 and bcllcrank 51 which causes the cutter bits 28 to be retracted or withdrawn inwardly and thus permit the cutter bits to return through the slot or groove without contacting the sides thereof, as shown in Fig. 6. The retraction of the cutter bits 23 and the raising of cutter bits 26 and 27, so that they pass through the grooves cut by cutter bits 27 and 28, respectively, permits the work to be rapidly returned to the starting point without the danger of the cutter bits contacting the side walls of the groove and thus prevents the possibility of damaging the workpiece or the cutting edges of the cutter bits.
Upon return of the work to its starting position the clapper box 22 is automatically pivoted downwardly thus causing the wedge 45 to move the cutter bits 28 outwardly and the tool 23 is lowered a predetermined dis tance to position the cutter bits 26, 27, and 28 for a subsequent work stroke.
Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
What is claimed is:
1. In a slotting mechanism for operating upon a workpiece with alternate cutting and return strokes, a bifurcated laterally resilient cutter holder, a plurality of cutters mounted on the holder, means to move the cutters outwardly upon the start of a cutting stroke to engage in a workpiece, means to adjust the extent of the outward movement of said cutters, and means independent of the workpiece to move the cutters inwardly upon the start of a return stroke whereby said cutters pass free of the workpiece during the entire return stroke.
2. A slotting and grooving tool for machining deep slots in a workpiece comprising a bifurcated cutter holder, a pair of cutters mounted on the holder, a bcllcrank pivotally mounted on said holder, a wedge cam mounted on the bcllcrank, and means to actuate said bcllcrank to move the wedge cam between the cutters to cause the cutters to move outwardly into engagement with the workpiece.
3. A slotting and grooving tool for effecting deep slots in a workpiece comprising a bifurcated tool holder formed of resilient material, a pair of diametrically opposed cutters mounted on the tool holder, a wedge cam for separating the bifurcations of said holder, a wedge cam supporting means pivotally mounted on the holder, and means operable upon the start of a workstroke to actuate said supporting means to cause the wedge cam to separate the bifurcations, whereby said cutters are moved into engagement with the workpiece, said actuating means again operable upon the termination of the means to vary the extent of the lateral movement of said cutters.
5. A slotting and grooving tool for machining slots in a workpiece comprising a bifurcated cutter holder, each portion of the holder formed by the bifurcation having a slot therein, a pair of diametrically opposed cutter bits each mounted in one of the slots, a wedge cam for spreading apart the cutter carrying portions of said holder, a wedge cam supporting means pivotally mounted on the holder, means to actuate the supporting means to cause the wedge cam to move between the cutter-carrying portions of the holder and move the cutters into engagement with the workpiece, and means to vary the extent of travel of the cutters.
6. A slotting tool for machining deep slots in a workpiece comprising a cutter holder having a pair of resilient cutter carrying legs, each of said legs having a slot formed therein, a pair of diametrically opposed cutters mounted in said slots, a bellcrank pivotally mounted on the holder, a wedge cam secured on said bellcrank, means operable upon the start of a work stroke to cause the wedge cam to move between said legs and move the cutters outwardly into engagement with the workpiece, and means to vary the extent of movement of said cutters, said actuating means again operable upon the conclusion of the work stroke to withdraw the wedged cam and thereby allow the legs to move the cutters inwardly whereby the cutters may. move relative to the workpiece and return to a work stroke start position without contacting the machined portions of said workpiece.
7. In a slotting mechanism, a depending blade having a first cutter mounted thereon, a second cutter mounted on the blade forward of the first cutter, a bifurcated tool holder secured on the after portion of said blade and having a pair of third cutters mounted thereon, means for separating the bifurcated portions of said holder to move the third cutters laterally of a work stroke, means for actuating said separating means to extend the third cutters and to lower the blade upon the start of the work stroke, said first, second and third cutters each forming slots of greater width in a workpiece than the preceding cutters, said actuating means raising the blade at the end of a cutting stroke to lift the first and second cutters into slots formed by the second and third cutters respectively and causing the retraction of the third cutters so as to permit the first, second and third cutters to clear the workpiece on a return stroke. 1
8. In a slotting mechanism, a depending blade having a first cutter mounted thereon, a second cutter mounted on the blade forward of the first cutter, a bifurcated tool holder secured on the after portion of said blade, a pair of diametrically opposed third cutters mounted on said holder, a bellcrank pivotally mounted on said holder, 21 wedge cam mounted on the bellcrank, means for lowering the blade and actuating the bellcrank to engage the wedge cam and cutter holder to move the third cutters laterally of a work stroke to engage the workpiece upon the start of said work stroke, said first, second and third cutters each forming slots of greater width in the workpiece than the preceding cutters, said actuating means raising the blade at the end of a cutting stroke to lift the first and second cutters into slots formed by the second and third cutters respectively and causing the retraction of the third cutters so as to permit the first, second and third cutters to clear the workpiece on a return stroke.
9. A parting and slotting tool for machining operations wherein the tool makes repeated passes over a workpiece to form therein a deep slot with finished side walls, said tool having a main cutting edge to form a groove in the workpiece as the tool is moved through its cutting stroke, laterally extendible cutting edges disposed on the tool to the rear ofthe main cutting edge to sequentially finish the side walls of the groove formed by said main cutting edge, and means for retracting the laterally extendible cutting edges from engagement with the groove side walls upon return movement of the tool.
10. The method of providing a deep groove in a planar surface with a machining tool comprising removing a strip from the surface to form a groove therein, relieving the walls of the groove to a depth less than the depth of the groove, and raising the tool on its return stroke whereby it may be passed through the relieved portion of the groove in returning to a new cutting position.
References Cited in the file of this patent UNITED STATES PATENTS 409,451 Caldwell Aug. 20, 1889 508,982 Rolston Nov. 21, 1893 828,425 Ruedy Aug. 14, 1906 927,450 Chemack July 6, 1909 1,025,152 Mitts May 7, 1912 1,327,410 Simeone Jan. 6, 1920 1,419,448 Davis June 13, 1922 2,275,327 Sheridan Mar. 3, 1942