US2675744A - Machine for forming sckew briver - Google Patents

Description

TYPE

J. N. PETRE April 20, 1954 E FLUTED 8 Sheets-Sheet 1 Filed Feb. 1, 1951 N a 5 m Q m & $8 l an m mm M i %M o Q Q Q Q Q h ww A Q. .l... Hilii 9. i v mm a awagag m a w m 9 g Q QR ZSnvcntor J0 n N. Petra,

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MACHINE FOR FORMING SCREW DRIVER BITS OF THE FLUTED TYPE 8 Shets-Sheet 5 April 20, 1954 Filed Feb. 1, 1951 Inventor Jobnfljefre,

o-uFvuo Gttomeg N%\ H Q R Q g l. mf gg a w m M 1, Q a rf @Rw g V ..|l i{.| Em R Q 3 WW April 20, 1954 PETRE 2,675,744

MACHINE FoR FORMING SCREW DRIVER BITS OF THE FLUTED TYPE Filed Feb. 1, 1951 s Sheets-Sheet 6 E Q Q N Z'mventor Gttorneg JolmN Pejre,

J. N. PETRE 2,675,744

MACHINE FOR FORMING SCREW DRIVER BITS OF THE FLUTED TYPE April 20, 1954 8 Sheets-Sheet 7 Filed Feb. 1, 1951 John N. 1 3??? (Ittorneg April 20, 1954 J. PETRE 2,675,744 I MACHINE FOR FORMING SCREW DRIVER BITS OF THE FLUTED TYPE Filed Feb. 1, 1951 8 Sheets-Sheet 8 Bummer J05)? N Pefre, I L 111.

Patented Apr. 20,1954

STATES 1. OFFICE MACHINE FOR FGRMHNG SCREW DRIVER BITS OF THE FLUTE!) TYPE John N. Petre, Orchard Park, N. 31., assignor to XceLite, Incorporated, a corporation of New York 15 Claims.

This invention relates to a machine for forming fluted bits upon an end of the shank of a screw driver according to the method disclosed in my copending divisional application, Serial No. 275,620, filed March 8, 1952.

Screw drivers of the fluted bit type are known in the trade as Phillips screw drivers and are of the substantial construction shown and described in the Phillips patent, No. 2,046,837, and the Phillips and Fitzpatrick patent, N 0. 2,046,840, both of which were issued on July 7, 1936. Such screw drivers are cooperative with screws of the particular type which are known in the trade as Phillips screws. These screws are of the substantial construction shown and described in the Phillips Patent No. 2,046,837 and the Phillips and Fitzpatrick patent, No. 2,946,839, also issued on July '2, 1935, and are characterized by sockets of special form in their heads. These sockets provide webs which, in relation to the vertical or longitudinal axes of the sockets, are of re-entrant angular contour and have rather sharp apices which extend downward from the upper face of the screw head. The webs are separated and delimited by recesses which extend radially in relation to the vertical or longitudinal axes of the socket.

The fluted bits are generally polygonal in cross section conform generally in cross sectional contour to the cross sectional contour of the sockets the heads of the Phillips screws. The conforming cross sectional contours of the bits and the sockets in the screw heads may be varied as shown, for example, on Sheet 2 of the drawings of the Phillips Patent No. 2,046,837. In practice, however, the bits and cooperating screw head recesses have been made of general cruciform outline.

The machine of the invention is available for the production of fluted bits of various cross sectional contours. As herein disclosed the machine is designed for the production of fluted bits of the general cruciform outline which accords with standard usage.

In the construction which has become standard the flutes of the bits are separated by equidistantly spaced vanes which provide the flute side walls and. the side walls of each flute extend inward in converging relation and meet along a line located in a central longitudinal plane of the shank. This line may be said to be the base of the flute and extends upward and outward from the terminal of the bit. Thus the flute bases have an upwardly diverging mutual relation. When the bit is fitted in the socket of the screw head the bases of the flutes engage the upper ends of the apices of the re-entrant screw head webs with wedging eflect, the vanes coniormably fit within the recesses of the socket with keying effect (that is to say for the purpose of rotation they positively couple the bit as wedged in the socket to the screw head) and the core of the bit is located within the central portion of the socket, i. e., the portion of the socket bounded by the apices of the Webs. The flutes are formed by rotary cutters and their bases have an incidental concave curvature in lineal outline, this curvature being so gentle or, more exactly, about such a long radius, that it does not interfere with the proper, i. e. functioning, angularity of the base of the flute. The angularity of the bases of the flutes with reference to the longitudinal axis of the bit is of quite small degree and in practice, according to circumstances, may be varied within narrow limits. Generally speaking the angularity of the bases of the flutes is of the order of from five to ten degrees. It will, of course, be understood that such angularity and the longitudinal and transverse dimensions of the bits will be varied in accordance with the varying dimensions of the screw heads and their sockets within the range of manufacturing sizes. In other words each bit is especially designed for coordination in use with a screw head socket of some particular longitudinal and transverse dimension.

In the machine heretofore used for the formation of the fluted bit of a Phillips screw driver the flutes are cut, one at a time, in successive operations. For this purpose a single rotary milling cutter is provided and the shank, suitably mounted to secure the requisite angularity of the longitudinal out which provides the flute, is fitted in a rotatable index feature. Four separate and successive cutting operations are required. Thus the shank is advanced toward the cutter for the first cut and is then withdrawn; utilizing the index feature it is then turned about its axis to the appropriate number of degrees, 1. e., ninety degrees for a bit of cruciform cross section, and is again advanced toward the cutter for the second cut and again withdrawn. These operations are continued until four cuts have been made. In connection with the repetition of these operations the angularity of the shank must be appropriately changed for each successive cut in order to insure the appropriate angularity of the base of the flute. The cutter exercises lateral pressure upon the terminal portion of the shank. In

some machines special provision is made for opposing such lateral pressure. In many machines the lateral pressure is unopposed. Unopposed lateral pressure, particularly where the shanks are relatively thin, frequently results in the distortion of the terminal portion of the shank during the cutting operation as a consequence of which the flutes will be of improper formation or relation. When this happens the shank must be discarded.

The prior machines, because they can cut only one flute at a time, impose the necessity of separate and successive cutting operations, the intermediate operations of the index feature, and the intermediate changes in the position of the shank in order to insure the proper angularity of the base of the flute. It follows that the formation of the fluted bit requires an extravagant period of time and the production capacity of the machine is relatively low. In prior machines where the cutter exercises unopposed lateral pressure upon the shank an additional factor which lowers the production capacity is thereby introduced, not to mention the waste represented by shanks that are necessarily discarded.

The invention accomplishes the following broadly stated objects, viz.: a series of simultaneously produced preliminary cuts, one for each flute, followed by the cutting of all of the flutes simultaneously; the neutralization of lateral pressures exercised upon the shanks during the cutting operations; the planishing of the flutes upon the completion of the cuts; and provision for predeterminately varying the angularity of the flute bases and the lineal and cross sectional dimensions of the flutes as circumstances may require. By virtue of these objects, the following substantial advantages are achieved, via: without increase of labor the production capacity of the machine is several times greater than the production capacity of the prior machines, i. e., between three and four times greater; thus whereas the prior machines have an average production capacity of six hundred fluted bits per day, the machine of the invention will turn out twenty-two hundred fluted bits per day; the flutes are cut with the greatest possible speed; all liability of distortion of the shanks during the flute cutting operation is avoided and uniform and perfectly formed flutes are always pro,- duced; expensive waste, represented by malformed flutes and discarded shanks, is eliminated; without any separate operations or separate operating features the flutes are effectively planished and freed from all burrs or surface irregularities; and bits may be produced to conform to Phillips screws as varied throughout the manufacturing range.

The invention consists in the novel features of combination, relation, structure and operation of the machine.

In the accompanying drawings:

Figure l is a front elevation of a machine in accordance with the invention and which is constructed to form fluted bits of general cruciform outline.

Figure 2 is a bottom plan view of the machine.

Figure 3 is a horizontal sectional view on the line 3-3 of Figure 1, looking in the direction of the arrows, various openings in the table for cooperation with sundry attachment bolts or screws being omitted.

Figure 4 is a perspective view of a portion of a cam ring with an attached cam, this being one of a series of similar cams mounted on the ring 4 and used for raising and lowering the several cutters.

Figure 5 is a top plan view wherein the table of the machine is partly broken away, this view being limited to the showing of sundry features of a pneumatic system for controlling the operations of various parts of the machine.

Figure 6 is a cross section on the line 6-$ of Figure 3 showing a gage for insuring the proper initial location of the shank relatively to the cutters which form the flutes and also showing a collet which is fitted upon the shank and by means of which the shank is properly positioned in the machine, this collet, as a matter of convenience, being referred to as a locational collet.

Figure 7 is a side elevation of the shank and the locational collet applied thereto, this figure assuming the previous use of the gage shown in Figure 6.

Figure 8 is a view partly in longitudinal section and partly in side elevation of one of two similar automatically operative pneumatic valves of the four-way type for the operation and control of certain mechanisms incorporated in the machine.

Figure 8a is a plan view of the base plate of the automatic valve shown in Figure 8, a plate valve which forms a part of the automatic valve being shown in horizontal section.

Figure 8b is a central longitudinal section of a bleeder valve, several of which of similar construction are incorporated in the pneumatic operating and controlling system which includes the two four-way valves of the construction shown in Figure 8.

Figure 9 is an enlarged partial top plan View of the machine showing the carriage for the shank and sundry mechanical features associated with the carriage together with parts of the cams shown in Figure 4 and the. ring upon which the cams are mounted, the cutter units being omitted from this figure in order to promote clarity of illustration.

Figure 10 is an enlarged partial top plan view of the machine showing the arrangement of the cutter units and the gearing for the operation of the cutters, the carriage for the shank being partly broken away in order to promote clarity of illustration.

Figure 11 is a vertical sectional View on the line H-H of Figure 10, looking in the direction of the arrows.

Figure 11a, is a fragmentary sectional view in the same plane as Figure 11 and showing on a larger scale certain details of a guide bar and its mounting.

Figure 12 is a vertical sectional view on the line i2--l2 of Figure 9, looking in the direction the line l5l5 of Figure 14, loo-king in the direction of the arrows.

Figure 16 is a perspectiveview of the cam mechanism for effecting and controlling the movements of the carriagefor the shank;

Figures 17 to 20 illustrate the novel method which is practiced by the machine and which forms the subject of my copending divisional application, Serial No. 275,620.

Figure 17 is a diagrammatic view showing the shank in the course of its downward movement relative to the cutters as having reached the position wherein the preliminary cutting action is initiated.

Figure 18 is a diagrammatic view showing the relation of the shank and the cutters at the beginnin of the flute cutting operation.

Figures 19 to 22 appear on Sheet 1.

Figure 19 is a diagrammatic view, corresponding to the diagram of Figure 18, showing the shank as completely moved into operative relation to the cutters and in a relative position wherein the preliminary cuts have been completed and the cutting of the flutes is initiated, the axes of the cutters at such time being in their normal or lower common horizontal plane.

Figure 20 is a similar diagrammatic view showing the relation between the cutters and the shank at the completion of the formation of the bit, the cutters having been moved to a position wherein their axes are in a common horizontal plane above their normal horizontal plane.

Figure 21 is a side elevation of a terminal portion of the shank upon which the fluted bit has been formed.

Figure 22 is an end elevation of the bit shown in Figure 21.

The various parts of the machine are supported by a horizontal table I mounted upon legs 2 which are preferably of channel cross section and are provided at their upper ends with horizontal flanges 3 and at their lower ends with horizontal plates l (Figures 1, 2 and 11). The legs 2 are arranged adjacent the ends of the table I. The flanges 3 provide direct support for the table and are secured to the table in any suitable manner, e. g. as by screws 5. The plates d rest upon the floor and provide floor engaging surfaces of suitable extent to insure the stability of the machine.

The principal elements of the machine are a carriage designated generally as 6 for holding the screw driver shank S (Figures 11 and 12), a series of milling cutter units designated generally as 7 (Figures and 11), and a mechanism designated generally as 8 (Figures 2, 4, 9 and 11) for effecting the upward and downward movements of the milling cutters.

The shank holding carriage The shank holding carriage 6 includes a horizontal bar 9 supported for positively guided rectilinear movement above the milling cutter units and having two positions, via, a normal upper or distant position and an operative lower or near position. Adjacent one end (its left end, Figures 1, 11 and 12 being considered) the bar 9 is mounted for vertical sliding movement upon a vertical post It. On its lower face the bar 9 carries a collar Ii slidably surrounding the post it and providing a shoulder I2. The post I!) is carried by and extends upright from a suitably formed bracket is attached to the table I and providing an annular shoulder I4. An expansive helical spring I5 surrounds the post NJ and is located between and reacts against the shoulders I2 and It. Adjacent its opposite end (its right end, Figures 1, 13, 14 and 15 being considered) the bar 9 rests upon a spring supported horizontal plate It suitably mounted for vertical 6 movement and positively guided in its movements. As shown, the plate I6 is connected to the upper ends of a pair of vertical posts I! which fit slidably in sockets I8 in a fixed block I9 (conveniently attached to the standard 23 to be later described). An expansive helical spring as surrounds each post I7 and is located between and reacts against the base of the socket is and the under face of the plate IS. The upper face of the plate It has a terminal bevel formation 2! adjacent an edge face (Figures 13 and 15) which is utilized when the bar 9 is swung about the post Ill as a pivot from an inoperative position (dot and dash lines in Figure 9) to its normal position in the upper plane (Figures 13 and 14 and, broken lines, Figure 19).

The table I carries a pair of upright standards 22 and 23 (Figures 1, 9 and 10.) secured by bolt fastenings 24. The standard 22 is formed with a recess 25 open to a vertical face. The standard 23 is formed with a similar recess 26. The recesses 25 and 26 are presented in opposite directions, i. e., the standard 22 at the left end of the machine (Figure 1) has its recess 25 open to its rear face and the standard 23 at the right end of the machine has its recess 26 open to its front face. Each of the recesses 25 and 26 (Figures 14 and 15) provides outer and inner shoulders. Corresponding shoulders are at corresponding locations on the standards and their planes are therefore parallel. As herein disclosed the shoulders are in upper and lower relation. The outer shoulder is preferably in the form of a horizontal anti-friction roller 2'? having trunnions mounted in opposed vertical walls of the recess. The roller 21, with its lower side exposed in the recess, overhangs the flat hori zontal inner shoulder 28 which is preferably coextensive with the width of the bar 8. The rollers 2? limit the upward movement of the bar 9 as effected by the springs I5 and 26 and the shoulders 28 limit the downward movement of the bar 9 and provide stable rests for the bar 9 in its lower position.

The mechanism for operating the shank holding carriage The rollers 2i also cooperate with the mechanism, indicated generally at 29 (Figures 1, 9 and 16), for effecting the movement of the bar 9 from its upper position to its lower position. This mechanism includes a straight horizontal operating lever 39 having two alining arms 3! and 32 which may be said to be delimited by apivotal connection 33 between the lever 39 and the bar 9. The pivot 33 extends through a suitabiy located opening 34 in the lever 36 and is fitte in or to the bar 9 and also in a bracket ures 9 and i l) secured to the bar and o hanging the lever 36. The arm 31 proje a rearward direction beyond the pivot 33 and th arm 32 projects in a forward direction. The arm. Si is pivotally connected near its outer end to a horizontal link 35 and the arm is similarly pivotally connected to a horizontal link 32 The links 36 and 31' extend in opposite directions from the lever 32, the link 36 extending to the right (Figures 9 and 16 of the drawing being considered) andthe link 31 extending to the left. The link 36 is pivo-tally connected at its outer end to a horizontally extending cam member 33 of the slidable wedge type and the link 31 is pivotally connected at its outer end to a horizontally ex-,

tending cam member 39 similar in all respects to the member 38. The members 38 and 39 have flat bottom faces and rest directly upon the bar 9. Their movements in either direction, as directly effected by the links to which they are connected, are longitudinally of the bar 9 and they are positively guided in such movements. For this pmpose the members 38 and 39 are formed adjacent their bottom faces and at each side with laterally projecting straight longitudinal flanges 49 and are sliclable in Ways provided by guides l! and 4'2, the guide 4! being attached to the front face of the bar 9 and the guide 42 being attached to its upper face. The guides ii and 42, as shown in Figure 13, are formed for overhanging engagement with the flanges 40 and thereby confine the cam members in the guide ways. The upper faces of the members 38 and 3e are fashioned to provide the cam action and, for a purpose to be later described, have a twostage inclination. The first stage is provided by an inclined face and the second stage is provided by an inclined face l 'l. The inclined face which may be called the outer cam face, terminates at the outer end of the cam member and the inclined face it, which may be called the inner cam face, extends between the face 33 and the upper face of the cam member. The face :13 has a greater degree of inclination than the face d4. Thereby the face 33 effects a relatively quick action and the face it effects a suitably slower action. In the operation of the mechaof which is such that if occasion should require it may be used as a handle for the manual operation of the mechanism. In the normal relation of the parts as shown in Figures 1 and 11 the bar s is in its upper position (which corresponds to the position shown in broken lines in Figure 19) and the wedge members are interposed to some extent between the rollers El and the upper face of the bar 9, the rollers 2? at such time resting upon the outer cam faces l3. With the parts this relation the lever 35, by the application power to its arm 32, is moved about the pivot in order to effect outward movements of the links and 3! and of the cam members 38 and Figure 9 of the drawing being considered, this movement of the arm 32 is to the left and is continued until the lever reaches the position shown in broken lines. This movement of the lever causes the cam faces t3 and M to react successively against the rollers 27 with the result,

that the bar & is given rectilinear downward movement in opposition to the pressure of the ngs i5 and 20. At the completion of the outeby positively hold the bar 9 in its lower posias shown in full lines in Figure 19. The "ward movement of the bar 5 caused by the hon of the outer cam faces d3 against the llers is at a more rapid rate than the connued downward movement of the bar 9 caused by the reaction of the inner cam faces at against the rollers 2?. The transverse lines 65 at which e cam faces :3 and Gil adjoin substantially corin location to the horizontal plane P re 1*?) which the shank initially engages e teeth of the cutters; this being the plane in h the later described preliminary cutting n is initiated. In aid of speed of operation desirable that the initial downward movell) of the shank, i. e., its movement prior to its en agement with the cutters, be quite rapid and the inclination of the outer cam faces 43 is determined with this consideration in mind. In

share 27 engage their upper fiat faces and order to prevent injury to the shank or the cutters it'is desirable that the downward movement of the shank immediately following its engagement with the cutters be not too rapid. It is for this reason that the inner cam faces M have less inclination than the outer cam faces 43. The above described movement of the lever 30 which results in the downward movement of the bar 9 is positively limited. This is accomplished by a bumper arm l5 located below the link 31 and secured by fastenings 46a. to the bar 9, the arm 46 projecting forwardly and inwardly from the bar. As an additional factor in the prevention of injury to the cutters or to the shank the arm it carries at its outer end a slidably mounted spring biased projecting bumper head 41 which is engaged by the arm 32 at a suitable point in its movement, i. e. a point substantially corresponding to the initial points of engagement of the inner cam surfaces 44 with the rollers 21, to cause the lowering of the bar 9 at a slower rate, and which retards and progressively cushions the continued operative movement of this arm.

The method The milling cutters 48 are of the same diameter and are arranged in angular and equally spaced relation with their axes of rotation in a common plane 1-1 (Figure 18) which is horizontal in the embodiment disclosed. In this plane the peripheries of the cutters are spaced to delimit a passage se of symmetrical contour (Figures 1 19 and 20). Figure 18 shows a shank S properly positioned for the cutting of the flutes. In the practice of the method (which forms the subject of my copending divisional application, Serial No. 275,620) the shank S, which has a diameter suitably greater than the minimum sectional dimension of the passage i9, is moved in the direction of its vertical axis A and in a direction normal to the plane H into the passage, the axis A being in alinement with the axial center of the passage 49. The movement of the shank is continued to a point at which the lower ends of the bases ofthe flutes at the initiation of the cutting of the flutes will lie within a horizontal plane P. This plane is located below the plane P and may be in substantial coincidence with the the plane H or it may, as herein shown, be slightly above it. The plane P prescribes the points E at which the succeeding step, namely the cutting of the flutes, commences, these points coinciding with the lower ends of the bases of the flutes. The angle of the bases of the flutes to the axis A of the shank is any case less than the angle ofthe bases of the preliminary cutsC (Figure 18) to the axis A. The location of theplane P is such thatithe points Ewill lie within upwardly diverging linesT tangential to the cutters and at an angle to the axis A which substantially corresponds to the general angle of thebases of the flutes to the axis A. In Figure 18 it maybe assuined that the bases of the flutes are'to extend at an angle of the order of seven degrees to the perpendicular, i. e., the axis A, in whichcase the tangent lines T will extend at an angle of seven degrees to the axis A. The tangent lines T extend at right angles to lines R which extend to the points E and are radii of the cutters. The angle of the lines R. to the plane H is the same as the angle of the lines 1 to the axis A. For exarnple if theangle of the lines T to means A beassumed as seven degrees the angle of the'lines B, to the plane H willbe seven decrees.

When the shank S is moved into the passage 49 to the position determined by the plane P (as shown in Figure 1'?) the cutters 28, during the final stage of the downward movement of the shank, will make preliminary cuts in the end of the shank, these conforming in basal lineal outline to the curvature of the cutters and facilitating the cutting of the flutes. The terminal portion of the shank (upon which the bit is to be formed) is of an outline which tapers to a point as shown at Y in Figure 17 from an annular line X at the cylindrical surface of the shank, a standard pointing machine being used for this purpose. The taper Y provides the socket engaging terminal portion Z of the bit (Figure 21). the taper of which conforms to the taper of the socket in the screw head. The preliminary cutting commences duringthe downward movement of the shank when the line X of the shank substantially coincides with the plane P. This relation is shown in Figure 17. The preliminary cuts are completed when their lower ends coincide wthe the points E in the plane P. Figure 18 shows the preliminary cuts as completed, their outline and extent, both above and below the line X of the shank, being indicated by broken lines C. The flutes are cut from points quite near the lower end of the shank to points on its cylindrical surface, these latter points being the upper ends of the bases of the flutes. The cutting of the flutes is accomplished by holding the shank stationary and at the same time effecting simultaneous coextensive movements of the cutters in angular directions having components opposite to the direction of movement of the shank and outward components of the same degree of angularity. In the embodiment disclosed these movements are upward and outward. Figure 2O assumes the complete cutting of the flutes. The tangent lines T conform in angularity to the movements of the cutters. Thus for the step of cutting the flutes the cutters are moved angularly upward from their normal positions N (broken lines) to or through raised positions (full lines) wherein their horizontal axes are in a common plane H parallel to the plane H and coincident with the upper ends of the bases of the flutes. Hence, the elevation of the plane H, indicated arbitrarily in Figure 18, will accord with the predetermined particular lineal extent of the flutes. When the axes of the cutters reach the plane H the cutting of the flutes is completed and thereupon, the shank being held stationary the while, the cutters are returned to their normal position, represented by the plane H, by an inward and downward movement along the same paths as their upward movement during which the cutters act with planishing effect upon the flutes. After the cutters 48 have been returned to their normal lower positions the bar 9 is returned to its normal upper position. This is accomplished by the application of power to the arm 32 whereby to move it back into its normal position shown in full lines in Figure 9. At such time the cam members 38 and 39 are withdrawn and the springs l5 and 2G raise the bar 9 until its movement is arrested by the rollers 27.

The gage for determining the position of the locational collet For the satisfactory use of the screw drivers accuracy, approaching precision, is required in the formation of the bits. For this purpose the bit must be accurately located in the machine. This is accomplished by a locational collet 5t (Figures 6 and '7) which is preferably in the form of an open ended sleeve split from one end to a point suitably intermediate its length, thereby to provide a pair of opposed resilient clamping jaws 5! of semi-circular cross section and which tend to spring inward. The collet is engaged with the uppper portion of the shank S and the distance D to which the shank projects beyond the collet is required to be exactly of a predetermined extent. This extent will be the same for screw drivers which require exactly similar bits. However, since the range of manufacture will require bits of various dimensions the extent D to which the shank S projects beyond the collet must be selected to accord with the particular bit which is to be formed and hence will be varied accordingly as the bit may conform to one or another set of dimensions. The selection of the extent D is effected by a suitable gage designated generally as 52 and which includes a vertical tubular casing 53, open at its upper end and formed with internal threads 54 extending for suitable distances from its lower end. The lower end of the casing 53 is closed by a screw stem 55 which projects into the casing and engages the threads 54. The stem 55 is held in any position to which it may be adjusted by a look nut 55 which bears against the lower end of the casing 53 and is provided at its lower end with a head 51 by means of which it may be positionably adjusted, that is to say, adjusted to project to a greater or less extent into the casing 53. The stem 55 and the casing 53 delimit a vertical well 58, the extent of which determines the distance D and the internal diameter of which slightly exceeds the maximum shank diameter within the manufacturing range. For a bit of some particular set of dimensions the required depth of the well 58 is determined by any appropriate shop measuring tool, the position of the stem 55 being adjusted to conform to and prescribe this depth. The distance D is the same for all bits which conform to a particular set of dimensions. When bits of another set of dimensions are to be made a corresponding change in the depth of the well 58 is required and the stem 55 is adjusted to effect this change, the extent of the adjustment of the stem 55 being predetermined from its previous position and any appropriate shop measuring tool being used in connection with the adjustment in order to insure the accuracy of the positioning of the stem as adjusted.

For convenience of use the gage 52 is preferably permanently mounted at one end of the table I (Figures 1 and 5). Thus the casing 53 projects through an opening in a bracket 59 and is suitably attached to the bracket, e. g., as by welding, the bracket serving for the attachment of the gage to an end of the table.

The use of the gage is illustrated in Figure 6. In such use the collet 50 is inserted over one end of the shank to an extent (sufliciently indicated by dot and dash lines in Figure 6) merely suificient for the collet to be stable upon the shank. The portion of the shank which projects beyond the collet is thereupon inserted into the well 58, the lower end of the shank coming to rest upon the upper end of the stem 55. The collet 58 is thereupon pushed downward upon the shank until its movement is arrested by the engagement of its split lower end upon the shoulder provided by the upper end of the casing 53, this position of the collet being shown in full lines in Figure 6. At such time the portion of 11 the shank which projects beyond the collet will have an extent equal to the depth of the well 58, this extent being the distance D. When the collet engages the upper end of the casing 53,

its jaws will exercise a frictional grip upon the shank of such degree that the shank and the collet are securely associated, that is to say the shank is held without any liability of accidental displacement relatively to the collet whereby when the shank is fitted in the machine the distance D is maintained. exactly as determined by the cooperation of the collet and the gage 52. Using the collet as a handle the shank is thereupon transferred from the gage 52 to the machine.

The mechanism for holding the shank in the machine The mechanism for holding the shank in the machine (Figures 1, 9, 11 and 12) is designated generally as as and is located centrally of the length of the bar 5 to which it is attached. This mechanism includes a cylindrical vertical casing 5! open at its upper and lower ends, the casing 6! being mounted in a central opening in the bar 9 and projecting above and below the bar. The opening in the bar 9 in which the casing is fitted is of enlarged diameter at its upper end in order to provide a shoulder for supporting engagement by a circumscribing flange 32 formed upon the casing, the upper face of the flange being flush with the upper face of the bar 9. The portion of the casing 6i which projects below the bar 9 is formed with an internal terminal taper 63. The casing 6i encloses a clamping collet 66 which is generally similar in construction to the locational collet 5B. Thus the collet Ed is preferably in the form or" an open-ended sleeve which is split from its lower end to a point suitably intermediate its length, thereby to provide a pair of clamping jaws 65 of a semi-circular cross section. Each jaw 65 is formed with an external taper 66 which extends to its lower end, the opposing tapers 66 presenting an inverted conical surface which bears against the taper 63 of the casing 61. The collet 6:: projects outward beyond the casing 5i and its projecting portion carries a circumscribing flange 8'! which is preferably in the form of a ring secured in fixed relation.

The collet 55 i formed with a central vertical opening, the diameter of which conforms to the diameter of the shank. The shank is inserted through this opening and projects to a suitable extent beyond the lower end of the collet.

Whereas the jaws of the locational collet 5!] maintain their secure engagement with the shank by reason of their inherent resilienc the jaws of the clamping collet 54 are positively urged into clamping engagement with the shank and are positively held in such engagement. For this purpose downward pressure is positively applied to the flange 6?. This downward pressure effects the movement of the collet 8-5 (the shank moving with it) from what may be called an idle position to a lower position which ma be called an active position. The movement of the collet thus efiected is so slight a to be scarcely sensually perceptible but it is sufiicient to cause the lower portions of the jaws 65 to exert very strong frictional clamping pressure upon the shank, this pressure being the result of the cooperation of the tapers 53 and 65.

The application of downward pressure to the flange 61 is efiected by a manually operated lever 68 pivotally connected to a bracket Be. This bracket consists of a straight horizontal plate it and a pair of vertical ears "II which extend upwardly from the plate at opposite sides thereof. The plate H3 has an opening through which projects the portion of the casing 51 above the flange 62. The plate ll! rests upon the upper face of the bar 9 and has overhanging engagement with the flange 52, being thus utilized to secure the casing 5| to the bar 9 in the relation above described. The bracket 69 is secured to the bar 9 by fastenings 12 which project through the plate it.

The lever 68 is of genera1 L-shaped outline and includes an arm 13 which provides a handle and preferably extends at a suitable upward inclination from the bracket 69. At its lower end the lever 53 has a forked formation which provides a pair of arms 14 extending in upward relation to the lower end of the arm 73.

The arms It are arranged between the ear 'il, each arm being adjacent the inner face of a corresponding ear. Pins l5 at the upper ends or the arms is pivotally connect the arms to the ears '3 5. At their lower ends the arms i l are provided adjacent their inner faces with vertical rollers it which, when the arm i3 is depressed, bear upon the flange 6i and apply downward pressure to the clamping collet 64. The rollers "it are so located that when the arm 13 is fully depressed their aXes will be very slightly beyond (to the right, Figures 9 and 11 being considered) a perpendicular plane passing through the pivots ii, that is to say slightly beyond dead center. This location of the rollers '15 insure that when the arm 13 is fully depressed the parts will be in locked relation, the clamping collet being thereby positively maintained in its active position. In order that the rollers may not be moved beyond their locking positions the bar it carries a post 7'! which is located under the arm TS near its lower end and which provides a stop for positively limiting the downward movement of the arm; When the arm it engages the post T; the rollers 16 are in the locking relation above described. When the bit has been formed upon the shank S and the shank is to be withdrawn from the machine the pressure on the clamping collet is relieved by raising the arm is to a suitable extent.

In the insertion of the shank S into the clamping collet the locational collet 55 i used as a handle and the downward free movement, of the shank through th clamping collet is continued until the lower end of the collet 523 engages the shoulder presented by the upper end of the collet 5G. The distance D above described then be" comes the extent of the shank between its lower end and the upper end of the collet 5-5. When the shank has been inserted to the permissible extent through the clamping collet the arm 73 is lowered until it engages the post; ii. Such downward movement of the arm 73 effects the very slight movement of the clamping collet from its idle position to its active position, the. shank S and the locational collet 50 participating in this movement. During the formation of the bit the shanks is rigidly and securely held by the collet 64. When the bit has been completed the cutters 48 are returned to their normal lower positions. Thereupon the bar 9 is returned to it upper position and the shank is removed from the machine. For this purpose the arm 73 is raised in order to relieve the pressure on the collet 6 5-. The frictional bearing of the portion of the arms it which surround the pivots l5 upon the adjacent faces of the ears H is of sufiicient degree to maintain the lever 68 in the position to which it is moved when the arm 13 is raised. When the pressure on the clamping collet has been thus relieved the shank is withdrawn by pulling it upward, the locational collet 50 being used as a handle. When the shank is pulled upward the clamping collet will move with it to the very slight extent which is sufficient for its jaws 65, by virtue of their inherent resiliency, to spring outward from the shank and thus release it at which time the shank may be freely withdrawn from the collet 65. When the jaws 65 release the shank the collet 64 will be in its idle position in which it is conditioned for the insertion of another shank and a repetition of the operations.

The milling cutter units The milling cutter units '1 (Figures 1, l and 11) are similar in construction and correspond in number to the number of flutes to be cut. The machine shown in the drawings is for the formation of bits of cruciform cross section and hence includes four units 1.

Each unit includes a milling cutter it which is mounted at the inner end of a horizontal shaft it. The shafts '53 are arranged in right angular relation to one another as best shown in Figure 10. Two of the shafts in offset relation extend longitudinally of the table and the other two, also in offset relation, extend transversely of the table I. The milling cutters of the shafts which extend in the same directions confront one another in spaced relation and the four milling cutters, each spaced ninety degrees from adjacent cutters, delimit the passage 49 above described. Each unit 7 includes a mounting plate 79 for the direct support of its shaft 18. The plate 19 is provided at its upper end with a pair of inwardly projecting parallel cars 30. The shafts 18 are journalled at their ends in suitable bearings (not shown) carried by the cars 80. Each unit 1 includes gearing for the operation of its shaft 18, the gearing of the several units, of course, being driven simultaneously. The gearing includes a vertical bevel gear at mounted in fixed relation upon the shaft 18 and a bevel gear 82 meshing with the gear 8!. The gear 82 is mounted in fixed relation at the upper end of a shaft 83. The gear 82 is supported in operative relation to the gear 8i by a bracket ti l which is attached by fastenings 85 to the plate 19. The bracket 84 provides a bearing for the shaft 83, the downward displacement of which relatively to the bracket is prevented by a spacing collar 33 fitted on the reduced projecting upper portion of the shaft 83 and arranged between the hub of the gear 82 and the upper face of the bracket 8'3. The mounting plate is has upward and downward movement in the operation of the machine and extends upward and outward at a suitable angle to the vertical, its angular setting being adjustably variable as will be later described. The shaft 83 is therefore driven by a universal shaft (Figure 11) designated generally as 8?, the two shafts being in slidable relation. The universal shaft 81 includes an upper section 88 and a lower section 89, these sections being connected by a universal joint 9i] of any suitable form. The part of the shaft 83 within the bracket 84 is formed with an axial recess 9! which extends to its lower end. The shaft section 81 projects into the recess 9|. The driving connection between the shaft section 8? and the shaft 83 may include keys 92 on the shaft section which are slidable in keyways 83 in the wall of the recess 9|. Each cutter unit 7 includes a supporting frame designated generally as 9/3 (Figures 10 and 11), one element of this frame being a base plate 95 (Figures 3 and 11) which rests upon the table I and which, for the purpose of positional adjustment, is mounted for movement in directions at right angles to the horizontal axis of the shaft '58 of the unit. The lower section 88 of the universal shaft 81 extends vertically and is journalled in a supporting block $5 secured by fastenings 9? to the inner end face of the base plate 95. A spacing collar 38 is pref erably interposed between the block 96 and the adjacent part of the universal joint 90.

The table I is formed with a central opening 99 of circular outline to accommodate the lower shaft sections 89, these projecting to a suitable extent below the table. The opening 9% also accommodates the blocks 95, the lower faces of which are preferably flush with the lower face of the table. The opening 99, as best shown in Figure 3, is provided with angular extensions me to accommodate attachment flanges of the blocks $5.

The gearing of the several units is driven from an electric motor it]! which may be conveniently mounted upon one of the legs 2 (Figures 1 and 2). The operative connections between the motor iiii and the universal shafts 81 may conveniently be of chain and sprocket form (Figures 2, 3 and 11). Each shaft section 89 carries at its lower end a sprocket Hi2 and the upper end of the motor shaft carries a sprocket I03, the sprockets W2 and H33 being coplanar. A sprocket chain iii l is engaged with the sprockets I62 and W3 and serves to drive all of the universal shafts 8'! in the same direction, the chain we being kept under suitable tension by a pivotally mounted spring biased tensioning arm i (Figure 2) hav ing a terminal roller for engagement with the chain.

Each cutter unit 1 in connection with the mounting of its shaft it includes three serially connected plates (Figures 1, 10 and 11), namely an inner plate, an intermediate plate and an outer plate. The inner plate is constituted by the mounting plate 19 above referred to. The intermediate plate Hi6 may be called a guide plate in that it has guiding cooperation with the mounting plate E9. The outer plate Hi? may he called a supporting plate in that it is the part to which the guide plate I05 is attached. The mounting plate 19 is formed in its outer face with a dove-tail groove I08 which extends between its upper and lower ends. The guide plate S93 is formed on its inner face with a dove-tail projection 189 which extends between its upper and lower ends and, conforming in cross sectional outline to the groove IE8, fits within it. The projection IE9 is, however, of somewhat less width than the groove in order to provide a clearer ee for a gib Hi3 which is used in accordance standard shop practice and is secured in any suitable manner to a wall of the groove Hit. The projection IE9 and the groove I68 provide connections between the mounting plate 19 and the guide plate Hi6 which permit the upward and downward movement of the mounting plate upon the inner face of the guide plate, guiding the mounting plate in such movement, and in all other respects positively couple these plates in rigid relation. The guide plate I86 is formed on its outer face with a dove-tail groove ill which extends transversely between its side faces. The

supporting plate I01 is formed on its inner face with a transversely extending dove-tail projection H2 which conforms in cross sectional outline to the groove HI and fits within it. The projection i I2 is dimensioned to provide a clearance for a gib H3 which is fitted between the upper face of the projection and the overlying face of the groove III, the gib I !3 being suitably secured to the adjacent wall of the groove Hi. The projection H2 and the groove Hi positively couple the plates H36 and iii! in rigid relation but permit a lateral adjustment of the position of th plate H36 relatively to the plate I87. This lateral adjustment is enabled by the universal joint of the shaft 8'? and is for the purpose of insuring accuracy in the centering of the cutters t-8 relatively to one another, that is to say of insuring accuracy in the symmetrical definition of the passage 19. Since the corresponding plates of the several cutter units 1 (mounting plates l3, guide plates IE6 and supporting plates it?) are of the same dimensions each guide plate, as adjusted, will occupy the same position relatively to its companion supporting plate as the guide plates of the other units. The adjustment, once made, is permanent for any set of cutters and needs to be repeated only as there may be a substitution of some one or more of the cutters or if, for any reason, it should become necessary to disassemble or reassemble any one or more of the units 1. The adjustment in any case is minute in lineal extent and may be efiected by horizontal screws H4 which bear against the side faces of the supporting plate Hi1 and have threaded engagement in openings in brackets l 55 riecl by and projecting outward from the guide plate Hi6 and suitably attached to its side faces.

The angularity of the paths in which the cutters e8 have their upward and downward movement varied in accordance with the particular pre determined angularity of the bases of the flutes. For this purpose the plates '19, I36 and Hi'l, serially connected as a group G, are mounted for angular, i. e. pivotal, adjustment. The cutter unit supporting frame 95 includes a pair of paralvertical side walls H5 suitably spaced and extending in upright relation from the base plate The supporting plate I? is mounted near lower end upon a transverse pivot pin ill -gures 1 and 11) which extends between the side walls H5. The plate 16'! is located between side walls H6 and its side faces are closely adjacent the inner faces of the walls i it. When the angle of the paths of movement of the cutters i to be adjustably varied the plate group G is moved as a unit in the proper direction and ough the proper degree about the pivot Ill, suitable shop measuring tool being used for the determination of the degree of movement. The walls Ht are connected near their upper ends by a draw pin I 18, one end of which is tapped as at HS (Figure 10) into one of the walls and the other end of which carries a knurled head 23 serving as a finger piece and bearing against the outer face of the other wall. The parts of the walls through which the draw pin i it extends have a certain measure of resiliency and normally are strongly held against the side faces of the plate ml by the draw pin M8, the connected plates G thus being clamped in the particular position determined upon. When the position of the group G is to be varied the draw pin H8 is backed ofi to permit the walls It to release the plate 3?, thereby to permit the free manual adjustment of the position of the plates G. When 16 this adjustment has been made the pin H3 is tightened, thereby to secure the plates G in the newly adjusted position.

The passage 49' may be varied in dimensions in order to accord with particular predetermined cross-sectional dimensions of the bit. In effecting such variation the cutters, with their in the common normal plane H, are adjustably moved toward or away from one another, the degree and relative direction of adjustable movement being the same in each instance. For the purpose of such adjustable relative positioning of the cutters the base plates of the frames 95 are mounted for slidable adjustment upon the table 1 in directions normal to the axes of the cutter shafts 78. Each base plate S5 is accordingly confined in a guide channel provided by a pair of parallel guide bars [2| and !22, one located at each side of the base plate. The guide bars are secured to the table l by bolt fastenings 123. The guide channels may be conveniently of dove-tail cross section. For cooperation with the guides l2! and if? each base plate is formed with longitudinally extending rabbeted grooves and I25, the walls of which extend from the side and bottom faces of the base plate and the cross section of which conforms to the cross-sectional outline of the guide channels, the guide bars conformably fitting within the grooves I24 and 25. In order to insure the perfect alinement of the base plates 95 the table I is formed in its upper face with straight grooves 126 (Figures 10, l1 and 1164). A groove I26 is provided for each base plate 95 and extends in the direction of adjustable movement of the base plate, that is to say in the same longitudinal direction as the base plate. One of the guide bars, e. g. the guide bar 12%, is provided along its outer edge with a longitudinal rib 52'! which projects downward from its bottom face and fits in the corresponding groove 23. In assembling the frames es of the units '1' upon the table i the guide bars i2? are initially secured to the table by their fastenings 123 with their ribs 12'! located in the grooves i26. The frames 94 are then positioned upon the table, the rabbeted groove we of each frame being engaged with the guide bar i2 l. Thus the guide bars l2! are utilized to effect the perfect alinement of the frames 94. The guide bar E22 is then engaged with the other rabbeted groove I25 and is moved to a position in which its fastenings 123 may be applied. Each frame is positively adjusted upon the table 5 by an adjusting screw I28 (Figures 10 and ll) which extends in the same longitudinal direction as its companion base plate 95 and is rotatably mounted in a bracket 29 located behind the frame and attached to the table 1 by fastenings 13%. Each frame 34 is formed above its plate 95 with a web l3i having a threaded opening which is engaged by the threaded portion of the screw [28. Accordingly as the screw I28 is turned one direction or the other it will project to a greater or less extent rearward from the web it! and the degree to which it projects from the web, its head bearing against the rear face of the bracket I29, will determine the position of the plate 95 relatively to the guide channel provided by the bars |2i and H2. In order to hold the frame St in any position to which it may be adjusted upon the table I a locking screw $32 is provided. The bracket 129 is formed with a threaded opening in which the threaded portion of the screw I32 engages. The screw 432 pro- 17 jects inwardly from the bracket I29 and is positioned relatively to the bracket to cause its head to bear with suitable pressure against the rear face of the web --I3I. Thereby the screw I32 effectively locks the frame 94 in the position to which it is adjusted by the screw I28.

The mechanism for reciprocating the cutters The mechanism 8 (Figures 2, 3, 4, 9 and 11) for effecting and controlling the upward and downward movement of the cutters d9 includes a series of cams I33, one for each cutter. The cams I33 are of the movable wedge type and are moved in opposite directions, .i. e. reciprocated, to raise and lower the cutters. The cams are mounted upon the upper face of a horizontal operating ring I34 to which they are rigidly secured by fastenings I35, the central opening I36 of the ring registering with the opening 9% in the table I. The shaft sections 89 project through the opening I36 and the sprockets m2 are located suitably below the ring I34. The movement of the cams I33 is produced by the rocking movement of the ring I34 in its plane and about its radial center. The ring is guided in its rocking movement by a series of conformably curved blocks I31 secured to the table i and arranged adjacent the under face of the table, the peripheral edge of the ring adjoining the inner faces of the blocks. The ring is sup ported upon ledges provided by plates I38 arranged below and secured to the blocks I31. The plates I38 are curved in conformity to the outline of the blocks and project inward from them, their projecting portions providing the ledges upon which the ring I34 rests. The blocks are secured to'the table 'I by fastenings -I 39 which are also utilized to secure the plates I38 to the blocks. The guide plate 193 is formed on its inner face with a recess I49 of suitable depth and which extends to its lower end. The upper wall of the recess I49 provides a shoulder MI. The recess I49 accommodates the upper portion of a post I42, the upper end of which is suitably spaced from the shoulder I 41. The portion of the post I42 within the recess I49 is rigidly secured, as by screw fastenings, to the base of the dove-tail groove I08 in the mounting plate I9. An expansive helical spring I 43 is arranged in the recess I40 between the post "I42 and the shoulder MI and reacts against these parts. The post I42 projects downward from the group of connected plates Gand is provided at its lower end with an anti-friction roller I44 which rides upon the surface of a corresponding cam I33.

Clearances for the downwardly projecting portion of the post I42 are provided by registering recesses I45 and I46 in the plate 95-and the table I respectively, the recesses I43 being formed as angular extensions of the opening 99 of the table I and being severally adjacent and at an angle to the recesses I99. The opposite movements of the cams I33 may be called advancing and retractile movements. In their advancing movements, which are clockwise (Figure 3 of the drawing being considered), the cams raise the posts I42 in opposition to the pressure of their loading springs I43 and thereby to a corresponding extent raise the mounting plates 19. The cutters 48, the shafts 18, the bevel gears BI and '82 and the shafts 93 participate in the upward and downward movements of the mounting plate. The springs I43 serve two purposes. One purpose is suitably to retard and cushion the upward movements of the mounting plates -19 in order that these movements may not be too abrupt, thereby avoiding liability of injury to the -cutters 48 and the shank S. The other purpose is to effect suitably more rapid downward movements of the plates I9 than would result from dependence on gravity -alone, =the springs thereby maintaining the contact of the rollers I44 with the surfaces of the cams. When the cams have reached the limit of their advancing movement the-cutting of the flutes has been completed and thereupon the cams are retracted to permit the downward movements of the mounting plates I9 and the return of the cutters 4-8 to their normal lower positions, "the cutters in such return acting with planish-ing effect upon the flutes as above described. During the upward and downward movements of the mounting plates 19 the shat-ts 83 are continuously rotated by the universal shafts '8? but are slidablewith relation to the universal shaft sections 88.

The extent of the upward movements or throw of the cutters 48 depends upon the degree of inclination of the cam surfaces and the extent-of theadvancingmovementsof the cams. These factors are selected to provide for a cutter throw of maximum degree, that is to saya throw which will enable the cutters to cut flutes of the greatest length "within the manufacturing range. It will be understood that cutters of different diameters maybe used, ideal practice involving the selection of 'a diameter which will accord with the extent of the flutes to be formed. The ring I3 3 is rocked by parts which are operated and controlled by a pneumatic system as hereafter described in detail. The lengthwise adjustment of the frames 94 as effected by the adjusting screws I28 is'inanycaseof such-slight extent and at such a comparatively slow rate that the rollers I44 of the posts 142 will readily move in either direction transversely of the cam surfaces as an incident of the adjustment, the Width of the cam surfaces being such that the rollers I44 will engage them in any position to with the frames 94 may be adjusted.

The bar 9, as above explained, is mounted for pivotal movement in a horizontal plane about the post to as an axis. In the event'that'access should be required to some one or more of the units I for such purposes as cleaning, repair -.or substitution of parts the bar 9 may be swung about the post It as a pivot from the angular position which it normally "occupies to an angular position at one side of the machine as shown in broken lines in Figure '9. Thereupon free :access a for any required purpose may be had to any one or more of the units "I. When the required work has been done and the units are again assembled in proper relation the bar 9 is then swung back into the angular position which :it normally occupies (Figures 13, 14 and 15) wherein what may be called its free endabuts the base of the recess '26 of the standard 23.

The pneumatic actuating system The mechanism :29 and the cam ring I34 are operated and controlled by a pneumatic system which, generally speaking, includes two .automatic valves of the type known in the trade as four-way, a number of bleeder valves and various pipes constituting the .air flow lines. One of the four-way valves I4! is provided for the operation and control of the mechanism 29 and the other four-way 'valve 148 :is provided for the operation and control of the .cam ring 134.

The purpose of convenience is served "by :locatmg the valves I41 and I48 according to the showing of Figure wherein the valve I41 is mounted upon the end face of the table I at the right and rear side of the table and the valve- I48 is mounted upon the upper face of the table -I adjacent its front side and its end face at the left. I Y

I The valves I41 and I48 are similar in construction and are of a well known type (the Keller type) which has been on the market for many years and-can be purchased from industrial supply houses. However, an understanding of the system of pneumatic operation and control involves the description of various details of these valves. These details are sufficiently shown in Figures 8 and 8a, it being understood that the description is applicable to both of the valves. The valve construction is shown in these figures in relation to the various air flow lines which are connected to it. Two reference numerals are applied to each flow line, one indicative of the valve I41 and the other indicative of the valve I48.

The four-way valve shown in Figures 8 and 8a consists of a base plate I49 by means of which the valve is attached to the table and a casing I56 which is secured to the plate I49 by screws I5I. The casing I50-provides a valve chest I52. A- piston unit generally designated I53 is mounted in the'valve chest I52 and consists of a pair of spaced pistons I54 and I55 of the same diametrical dimensions and a rod I56 connecting the pistons. Since the pistons I54 and I55 are of the same diametrical dimensions thevalve unit is perfectly balanced and will move in either axial direction accordingly as the pressure may be relieved upon one or the other of the outer faces of the pistons I54 and I55. The casing I55 is formed internally with alining cylindrical guides I51 for the respective pistons I54 and I55. The outer ends of the casing I50 are provided with end heads I58.- The piston I54, its guide I51 and the adjacent casing head I58 provide a pressure chamber l59, the outer face of the piston I54 being a wall of this chamber. The piston I55, its guide I51 and the adjacent head I58 similarly provide a pressure chamber- I60 at the opposite end of the valve chest, the outer,

face of the piston I55 being a wall of the chamber I56. The pistons l54and I55-are mounted upon the end portions of the rod I56. An axial duct or passage I6! of narrow diameter is formed in the rod I56 and extends from end to end thereof, the ends of the duct I6I communicating with the pressure chambers I59 and I60. The movement 'of the piston unit is in either direction of the longitudinal axis of the rod I53 and such movement results in one of the pressure chambers being progressively reduced in volume and the other pressure chamber being progressively increased in volume. In connection with the movement of the piston unit air will flow from the pressure chamber. which is being reduced in volume through the duct I6I to the pressure chamber which'is being increased in volume. The end heads I58 are provided with axially located threaded openings I62. As furnished by the manufacturer these openings are closed by removable plugs (not shown) The piston unit I53 operates a plate valve I64 which has'sliding movement upon the inner face I55 of the base plate I49, the face I65 providing the bottom wall of' the valve chest I52. 'The plate valve I64 is formed in its'underface with a recess I66 for 'controllingthe communication between certain ports to belater described. The plate valve I64 is mounted at the lower end of a stem' I61 which "has a-loose or free fit in a socket formed in a collar I68 located centrally of the rod I56 to which it is fixed; The valve I64 is biased against the face I65 by a helical spring I69 fitted upon the stem I61 and reacting against the valve I6'4'and the collar I68. When the piston unit I53 is shifted in either direction it effects a corresponding shifting movementof theplate valve I64 longitudinally of the bottom wall I65 of the valve chest I52. 7

The base plate I49 is formed with four laterally extending ports I10, I'II, I12 and I13. The ports I10 and I12 are open to one of the side faces of the base plate and. the ports Ill and I13 are open to the opposite side face of the base plate. The ports of each pair open to one side of the base plate are offset with relation to the ports of the other pair open to the op,- posite side of the base plate. The ports I10, I1I, I12 and I13 extendslightly more vthan half way through the base plate and at their inner ends are in communication with angularly extending ports I14, I15, I16 and I11, respectively, which are in open communication with the valve chest I52 through the inner face. I65 of the base plate. The port I12 is an exhaust which functions in both operative positions of the plate valve I54 and vents the compressed airto the atmosphere.

The piston unit I53 has two operative .positions in one of. which (which may be called its 1 left position) the piston I54 is located at the left end of the pressure chamber I58 (Figure 8 of the drawing being considered) and in the other or" which (which may be called its right position) the piston I55 is located at the right end of the pressure chamber I60. The angular ports I14, I15, I16 and I11, considered as a series, are arranged in succession along a longitudinal central line of the face I65. The plate valve I64 at no time covers theport I14. When the piston unit-I53 is in its right position the plate valve I64 covers the angular ports I16 and I11 and establishes two paths of flow, one-of which is from the port I13} to the port I12 and through the recess I66 and the other of which is from the port I10 tothe port HI and through the valve chest I52. Whenthe piston unit I53 is in its left position the plate valve covers the angular ports I16 and I15 and establishes two diiferent paths of fiow, one of which is from the port I'II-to the port I12 and through the recess I66 and the other of which is from the port I10 to the port I13 and through the valve chest I52. v

The features abovedescribed as I49 to I11 inclusive are common-to the valves I41 and I48. The changes in the how of air are effected in the same way by both valves. The normal positions or relations of the parts of the valves are the same in both instances. Y

The compressed airfor theysystem ofpneumatic operation and control is delivered by a line I18 from a storage tank. The line I18 communicates with two branches I19 and I80, the branch I19 delivering to the valve I41 and the branch I to the valve I48. I

The normal position of the piston unit I53 is its right position as shown in Figure 8. In this position of the piston units (of the two valves I41 and I48) all parts of the machine are in their normal positions and the machine is, therefore, ready for the cycle of'operations which are per,-

21., formed in the production of the drill bit. The operation of the machine i initiated by the manual actuation of a 'bleeder valve I8I (Figure which is conveniently located adjacent the front of the table I and is provided'at the end of ableed line I32'connect ed to the valve I41, the connection bcing vvith the head'I'58 at the left side of the valve (Figure 8 being considered) and the bleed linebeing in communication with the valve chest I52 through the opening I92. When the'bleeder valve I8I' is actuatedair is vented from the left end of the valve chest with the result that the pressure upon the 'outenf'ace-ef the piston I54 is relieved and the piston unit-is shiftedtoitsleftpositionji' The bleeder valve I9i is one of a series-of bleeder valve incorporatedfin the" system of pneumatic operation, the" remaining' blee'der valves being designated "as IE3, IS and I85 and being automatically operated in succession The blee'der valves I8}, we, I 85 and lili'are or-a vvell knotvn type and are similar'i'n construction; their details being shown ingigure de -Each bleeder valve includes a casing I95 h provides' a chamber $81 fin-communication witha conical valve seat' ie'ii externally formed upon the inner end vvall ofthe casing. ThefseatIBB accommodates a normally closed valve 189 provided at the lower end of 'a stem' '19e which projects through the casing and throughan openingfin its outer end' Wall,'the projecting portion of the stem carrying an operating button IS I' having a' hemi-spherically curved surface. The valve I89 is normally held'in its'closed positionbya spring I92 arranged within the' chamb'er I81 and reacting again st 'a shoulderhwshformed on'the casing 199 and a shoulder: I9 1 provided on the valve stem 99 near its uppeifendJ The casing I85 is formed 'v'vith vent openings 195 leading from the chamber I81. When th'ebuttonIQI is pushed inward against the pressureof "the spring I92 the valve 189 is movedaway from its heat and air is vented to the iatmos'pherethrough the chamber i9? and the vent openiii'gs' I95. The buttons I9I- of the several bleeder valves a re-i n vable elements fo the control 'of the hctuation of the difierent mechanisms with which the bleed'er valves are severally associated. I

The power for the operation ofthe mechanism 291$ delivered by'a piston I99 which is movable in'a cylinder E91, the flow'ot air; for theoperaf ti'on of the piston" I99 'being controlled 'by the valve i -ii. The: normal position of the piston I55 is'atthe'right end of thecyli'nder I91 (Figure 5 being considered). "'When the pawn I99 "is movedto theleftiend of'the cylinder [91 the mechanism 29 is bper'ated to'effect the'dovinvvard movement of the bar 9.' When the piston 'I95 is returned to its normalposition 'at' the right end of the cylinder I91 the mechanism' 29 is operated toprovide for the upward I'novem'ent of the bar 9 to its normalposition. Theleftward movement of the piston I 98 is governed by the'bleeder valve 19f and its return movementito' the'right is governed by the bleeder valve IB5vvhich'is"provided at the end of'a ble'e'd'line'ISB connected to the head 1590f the valve I91 'oppositethe' head to which the bleedlinellifi is co'nn ectedf The power'for' the operation of'the cam ring' lasis delivered by a piston Isa" which is movable in'a cylinder 290, the flow of air for'th'operati'on' o'f'the piston i99-be'ing controlledfby'the'valve' I48] The"normal 'po sitien of the iston I99 is at'the right 'end of the cylinder I98 (Figure '5' being considered). When'the piston' l'se is moved to' the left end of'the cylinder I93 the cam ring I 34 is operated upon its advancing stroke. When the piston'I99 is returned to it normal position at the right end of the cylinder 299 the cam ring is operatedon' its retractile stroke} The leftward movement of the piston I99 is governed by the bleeder valve I83 and its return movement to the right is governed by the bleeder valve I8 5. The bleeder valve I83 is at the end of a bleed line 2! connected to an and head I58 of the valve I 49. The bleder valve I84 is at'the end of a bleed line 292 connected to the head I58 of the valve I48 opposite the head to which the line 20! is connected. I

V The air for moving the piston I96 to its normal position to the right and for holding it in such position is delivered by a line 293 and the air for moving the piston I99 to the left and for holding it in such position is delivered by a line 294, the lines 293 and 295 being preferably flexible hose sections. "One end of the line 293 is connected to the left end of the cylinder I91 and the other end is connected to the base plate I45 for direct communication with the port I1I One end of 'the line 2-94 is connected to the right end of the cylinder I91 andits other end is con nected to the base plate I45 for direct communi-' cation with the'port I13. The air supply branch I19 for the valve I41 is connected'to the'base plate I45 for-direct communication with the port I19. The exhaust port I12 is preferably connected to an air exhaust pipe 295.

The air for moving the piston 199 to its normal position to the right and for holding it insuch position is delivered by'a line 299 and the air for moving the piston I99 to the left and for holding it in such positionis delivered by a line 2&1. the lines 2 06 and 291 being preferably flexible hose sections. I

One end of the line 299 is connected to the left end of the cylinder 200 and its other end is connected to the base plate I45 of'the valve M8 for direct communication with'th'e port I1i. One end of the line-201'is connected to'the right end of the cylinder 290 and its-other end is connected to the base plate I45 for directcommunication with the port 13. The air supply branch I19 for the valve I41 is connected to the base plate I for directcommun-ication with the port I 19. The

exhaust port I12 of the valve I48 is preferably connected to an air exhaust pipe 298, a

When' the piston unit of the valve M1 is-in its normal right position-air will flow from the delivery branch I'19 through the ports I1i and I14 into; the valve chest I52 and thence through the ports I15 and I1! and the line 293 to the left end of the 'cylinder I91 to-effect the movement of the piston I96 to the right. At the sam timethe air at'theri'ghtsideof the piston I96 will escape through the line 204, ports I13 and I11, recess I66, ports I16 and I12 and exhaust pipe 295 to atmosphere, When the piston unit of the valve I48 is in its normal right position (Figure 8 being considered) the paths of flow will beidentical, the air bein'g'delivered into the left end of the cylinder 200 through the line 299 and at the same time the air at the right side of the piston 199 escaping from the cylinder through the line 291 When the piston unit of the valve;l41 is in its left position (Figure 8 being considered) air will flow from the delivery branchl19 through the ports I10 and "I14 into the valve chest I52 and thence through the ports I11 and I13 and the line 204 to the right .end of the cylinder I91 to effect them'ovement of the piston 19.6 to the left.

At the'same time the air at'tlie left side of the piston will 'escap'e'through the 'line 203,- ports Ill and I15, recess II5,ports I and II2'an d exhaust pipe 285 to atmosphere. When the piston unit of the valve I48 is in its left position the paths of flow will be identical, the air being delivered into the right end of the cylinder 299 through the line 231 and at'the same time the air at the left side of the piston I99 escaping from the cylinder through the line 205; I

Support for the cylinder I91 '(Figures 9 and 13') is provided by'the bar 9 and the arm 32 of the mechanism 29. "A split or two-part bracket 299 is mounted in fixed relation upon the outer end of the cylinder I97. The inner part of the bracket 289 is provided with spaced horizontal ears 2I8 which provide a recess 2H that enables the bracket to be fitted to the outer end portion of the bar 9. The bracket is pivotally connected to the bar 9 by a pin 2 I2 whichextends throu h the ears 2 I I]. The rod 2 I3 upon which the piston I96 is mounted is pivotally connected at its outer end as at 2I4 to the arm 32 of the mechanism 29. The pivotal connection 2I 2 between the bracket 299 and the bar. 9 enables the cylinder I91 to swing in a horizontal plane in compensation for the movement of the pivot 2I4 through the arc of which the pivot 33 of thelever 38 is the radial center.

The piston I95 in its movement to the left swings the'lever 39 from the position shown in full lines in Figure 9 to the position shown in broken lines. As above explainedthis movement of the lever 39 results in the outward movement of the cam members 38 and 39 and the downward movement of the bar 9. The completion of the downward movement of thebar 9 is immediately followed by the actuation of the bleeder valve I83 for the purpose of causing the movement of the piston I99 to the left. g j

The bleeder valve I83 is mounted-on 'anangle bracket 2I5 (Figures 9, B and 14) which is'secured to the-standard 23 at'its'inner side, the valve I83 being located adjacent therearside of the bar 9 and projecting forwardlyfrormthe bracket 2I5. The cam member 38 of the mechanism 29 is utilized in connection withthe actuation of the bleeder valve I33; Thedirectactuating element is an anti-friction roller-2i 9 which moves with the cam member 38 and, upon the completion of the downward movement off-the bar 9, engages and depresses the button- I 9| of the valve I83 and 'then'releases it.- "The roller 2I8 is carried by an arm 2 I? which conveniently consists of a pair of plates. The arm '2I'I is pivotally connected as at2I3 to a supporting block- 2I9 carried by an angle bracket 220; 'The'block 2I9 is attached to the bracket '22I'Iby a'fastening 22I and the angle bracket is attached to the cam member 38 adjacent its upper face by fastenings 222 which pass through the horizontal flange of the bracket. The arm-2H projects-rearwardly from the block 2I9 and the roller 2I8' is fitted between the free ends of the plates which constitute the arm, its pintle being mountedin'these plates. The block 2 I 9'is provided at its outer end with a projecting ear 223 which extends between the plates of the arm 2H and in which the pivot 2 I 8 is fitted. The block 2 I 9-is formedwith-shoulders 224 adjacenttheear 223 and the arm- Z-I 'I is spring biased normally to rest against-them. The arm 2I'I is held rigid 'by the shoulders 224 during the outward movementof the cam member 38 and at the time when it'engages and depresses the button of the valve I83'and-movesbeyondit;

the'con'tinued outward movement of the roller 2 It releasing the valve which thereupon resumes its"normally closed condition." When the cam member' 38 is moved'inward upon the return stroke of the arm '32 the arm '2II yields onits pivot'w'hen' it en'gagesthebutton of the valve' I83 and rides over it, of course without an actuation of-the valve. When the roller 2I6 during the inward'movementof the cam member 38 passes beyond the valve I83 the'arm 2" is restored to its normal position in which it is held against the shoulders224.

Themovement of thepiston I99 to the left (Figures 3, 5 and 9 being considered) which results from the actuation of'thebleeder valve I83 efifects the movement of the cam ring I34through its advancing stroke. For this purpose the cam ring carries a rigidly attached arm 225-(Figures 2, 3 and 9) which projects forwardly beyond the table I and is of such length that it may serve as a 'handle for the manual operation of the cam ring I34 if such should be required. The rod 229 upon which the piston I99 is mount ed is connected by'a link 22! to the forwardly projecting part of the arm 225. The movement of the. piston I99 to the left effects a corresponding movement of the arm 225, that is to say-a movement of the arm from its full line position shown in Figures 3 and 9 to the position shown in broken lines in these figures during which the arm moves the cam ring I34 through its advancing stroke. The bleeder valve I84 is conveniently located adjacent the front'of the table I. When the arm 225 verynearly reaches the limit of its movement to the left itengages and depresses the button I9I of the bleeder valve I84 with the'result that the piston unit I I 53 of the valve-I48 is returned to its normal position,.i. e. its right position, as shown in Figure 8. Thereby the flow of air in relation to the cylinder 208 is reversed with the result that the piston I99 is returned to its normal posi-' tion at the right end of the cylinder 280 and the arm 225 is restored to its normal position as shown in full lines in Figures 3 and 9. The arm 225 during its return movement effects the movementof the cam ring I34 through its retractile stroke, thereby returning the cam ring to its normal position.

The bleeder'valve I85 is conveniently mounted adjacent the front face of the table I. The arm 225 is utilized'for its'actuation and is operative on'its return stroke for this'purpose. The actuation of the bleeder valve I85 is directly effected by a 'roller 228 which engages its button to move it inward, the operation being similar to that of the operation of the bleeder valve I83 by the roller'2I6. The roller 228 is carried by an arm 229 which is pivotally mounted upon a block 230, the. arm 229 and block 230 being similar in construction to-the arm 2I'I and block 2I9 above described. The block'230 is carried by the arm 225 and is mounted for any positional adjustment that may be required. For the purpose of positional adjustment the block 230 is formed with a slot HI and is connected to the arm 229 by a'fastener 232 which passes through the slot. When the roller 228 has actuated the bleeder valve I85 it passes beyond it, releasing the button with resultant closing'of the valve; During the next-movement of the arm 225 to'the left the engagement of the roller 228 with the button of the valve I89fwill result in the displacement of the arm 229 -whereby'the roller rides over the-button without actuating it. The actuationj

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