US972848A - Machine for cutting turbine vanes or buckets. - Google Patents

Description

H. GBISENH'GNER.

MACHINE FOB. CUTTING TURBINE VANES 0R BUGKETS.

APPLICATION FILED JAN. 27, 1902. v

Patented Oct. 18, 1910.

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v I H. GEISENHONER. I

MAGHINE FOR CUTTING TURBINE VANES 0R BUOKETS.

APPLIOATION FILED JAN. 27, 1902. v 1 Patented Oct. 18,1910.

3 SHEETSSHBET 2.

' lll lnvenCor: Henry Geisenhner,

, H. GEISENHUNER. MACHINE FOR CUTTING TURBINE VANES OR BUOKETS. APPLICATION IILBDJAN. 27, 1902.

3 SHEETS-SHEET 3.

Fig.8.

Fig.9.

' Hem y Geisenhtine r',

Patented Oct; 18, 1910.

Inventor:

HE RY GE rsE no R, on sen EcTAnY, NEW YORK, AssIGNoR T0 GENERAL ELECTRIC COMPANY, A CORPORATION on NEW YORK.

FOR CUTTING TURBINE VANES 0B,, BUCKETS.

Specification of Letters Patent.

Application filed January 27, 1902. Serial No. 91,329."

To all whom it may concern;

Be it known that I, HENRY GEIsENHoNEn, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and usefulImprovements in Machines for Cutting Turbine Vanes or Buckets, of which the following is a specification.

, Steam or. other elastic fluid turbines as commonly constructed are provided with one or more'revolving members each of which is provided with a circular row of vanes or buckets formed integral therewith. These vanes are of such shape'and are so arranged that the elastic fluid leaving the nozzle will impinge thereon and produce rotation. lVhen two or more rows of wheel buckets are provided for each stage,- it is necessary to provide intermediate buckets which may be stationary or rotary as desired, and these buckets receive motive fluid from one setof wheel buckets and discharge it at the proper angle against the adjacent set or sets of wheel buckets. Inorder to produce an efficient turbine, it is necessary to form these vanes with great care and accuracy. .In certain instances these vanes are so constructed that "the spaces or sinuous passages between them indrease 111 size toward the exhaust end of the machine by an amount which is just sufficient to compensate for the increased volume of the motive fluid. In certain other instances the vanes are so constructed that the spaces or pas sages between them enlarge toward the exhaust by an amount which is sutficient to convert an appreciable amount of. steam pressure into 'vz'soioa. Itwill be seen from the foregoing that the greatest accuracy is involved in obtaining the best results.

My invention has for its object to produce a machine which will cut the vanes accurately with a minimum expenditure of time and labor, and this without requiring workmen of more than average skill.

My invention further has for its object to produce a machine which can, by simple changes, be arranged to cut varies on wheels of largely varying diameters and different widths. The scope of the invention will be more fully described and claimed hereinafter.

In the accompanying drawings, which illustrate an embodiment of my invention,

' Figure 1 is a side elevation of the machine;

. center.

view illustrating the shape of the vanes cut in the turbine wheel; Fig. 7 is also a plan view of the vanes showing the cutting center displaced somewhat from the center of the wheel blank; Fig. 8 is a view in elevation of the detachable portion ofthe cam; and Fig. 9 is a sectional View showing the means employed to adjust the positions of the wheel blank on its support.

In the drawings I have shown my improved vaneor bucket-cutting mechanism applied to a lathe, but it is evident that it can be used in connection with other kinds of apparatus, either those especially designed or otherwise 1 represents the bed of the lathe having the. usual guides or ways, and mounted on theleft hand end is a head 2. The cone pulleys 3 are mounted on a driving spindle in the usual manner, the said spindle being provided with a screw-threaded end 4 to which is secured the revolving tool carrying head 5. The lathe is provided with the usual back gearing 6 which may or may not be used in cutting vanes as desired, One advantage of the construction illustrated is that it can be applied and removed from an ordinary lathe without in any way destroying its usefulness for ordinary purposes.

The vanes are preferably cut out of solid stock, and in the present instance are of the shape shown in Figs. 6 and 7 although the particular configuration can be varied withoutdeparting from the spirit of my invention. In' Fig. 6 the center of movement of the tool is coincident with a plane passing through the center of the blank, indicated in dotted lines. The sinuous passage7 is of the same width throughout, consequently the vane 8. is narrower at the edges than in the The portions of the side walls of the vanes between the dotted lines 9' are concentric, while the, remainder of the walls are straight, The depth of the passage may be the same throughout, or it may increase in depth by a greater or less amount by making ,the peripheral surface of the wheel a frustum of a cone instead .of a cylinder.

Patented Oct. 18. 1910.:

. radually increases.

This feature isindicated in Fig. 1. Under ordinary conditions'the cross-sectional area of each passage increases slightly .from the receiving toward the discharge end in order to compens'atefor the decreased velocity of the elastic fluid and to compensate for frictional retardation. I

In Fig.7 the centers of the arcs on which I the vanes are cut are displaced with respect to a plane passing through the center of the blank, as isindicated by the broken-and dotted line.. This. means that the shape of the vanes is slightly altered. If it is desired to modify the shape of the passage, as for example by increasing the width of the passage 7 at one end insteadof arranging it as shown,.-the blank'is first cut with grooves or passages having'parallel sides, as in Fig. 6.

The blank is then-raised with respect to the cutting tool and the operation of cutting is repeated, When this is done portions of the vanes 8 will be cut away, asindicated by dotted line 10, thus increasin the clearance on one side of the wheel, preferably theeX- haust.

' The path of the cutting tool while inthe act of cutting or forming the buckets follows a. path of varying radius; that is to say, fora portionof its stroke the tool moves in'thearcof acircle, and for the remainder, of its stroke theradial distance between the tool and ,the axis of the driving spindle mm Fig. 6, wherein the dotted lines 9 in dicate the'points' where the circular portion of the path ceases, andthe path of increasing radius begins. Inthe present instancethe cylindrical portion or surface of'the vane or bucket merges into a plane surface which is tangentially arranged with respect thereto.

In so far as the broader aspects of the "present invention are concerned, the ends of the buckets may be curved or stra ght, al-

though certain advantages are foundin male ing them straight. In either case the buckets are made thicker at the middle than at the ends, and have sharpened edges;,the latter buckets.

feature adds greatly to the efficiency of a turbine,"hence the importance ofhaving a.

machine which will accuratelv cut the In cutting the vanes the tool 11 is'rotated andtravels for a major portion of its stroke in the path of a circle while moving from one side of the wheel blank to the other. In

the present machine the tool 11 moves from the top to the bottom of the blank or vanecarrying wheel 12; in other words, in a plane at right angles to that of the wheel blank.

The motion of the tool being continuous and due to the rotation of the head 5, it is necessaryto provide some means for moving the tool in a manner to clear the periphery of the wheel blank 12 on the return or idle portion of its stroke. The means for imparting This is made plain this orbital motion to the tool will be' apparent by referring to Fig.6, wherein 7 rip;- resents the passages formed in the bla and 11 the tool shown ,in the act of cutting one of the passages. After the tool finishes its cut, itis moved under the blank to the position indicated by the dotted lines, after which it moves upward and across the top of the blank,-and again passes down through the passage 7 until the latter is cut to the desired depth. After one of the passages is completed, the blank is advanced an angular distance equal toon'e vane, and the same operation is repeated. .In order to impart the necessary movement to the tool to cut the stock and clear the blank on the return stroke,.a.special cam is provided which is formed partly in the detachable piece 13 (Fig. a), and partiallyin the; stationary support 14. The'support is provided with a hub-like projection which engages with the head of the lathe, and formed. on the back thereof are projections 15 which also en- Passin through the projections are retaining bots 16, the said projections being counter-bored to receivethe' heads of the bolts, The support 14 is providedwith a large circularopening to receive the detachhead, and this with a small expenditure of labor. The cam isiretained in place by the keys 15 and the screws 16, the latter being provided with washersthat extend over-the edge of the cam. Formed in the stationary support is a cam-groove which coincides with the groove 17 formed in the detachable portion 13. The totaldistance between the ends of the cam-groovethus formed issuflicient to move the tool '11 out of engagement with the blank on the return stroke. It is evident that for some blanks the movement will be rather more than is necessary, while in othersit will bejust enough; but the savinginthe use of a single support 14 is great enough to compensate for this slight loss. For larger or smaller machines the length of the groove will be varied to suit the given conditions-but in any event it should be great enough to cause the tool to clear the blank on" the idle or. return portion of its stroke. The'portion'of the cam-groove 17 gage with the stationary head of the lathe.

which directs the cutting tool through the blank is concentric with-thece nterlof rhovement, but its shape can be altered to suit any given condition. I J Mounted in a slot 1n the revolving head 5 is a slide 18 which is provided on the back side with a pin and roller 19 (Figs.- 3 and 4), the latter traveling in the cam path 17, and as the head 5 is rotated ,this slide is moved toward and away from the center of revolution. Mounted on the rotating head is a stationary abutment 20, and between this abutment and the slide 18-is a compression spring 21 which tends at all times to force. the CZIIIl-TOllBP'lQ against the outer edge of the canrgr'oove. Adjustably mounted on the slide 18 is a support 22 which carries the tool holder 23. On the back of the support 22 is a projection, shown in dotted lines in Fig. 1, and this. projection is provided with a screw-threaded opening for receiving the adjusting screw 44. The tool holder should have a certain amount of spring in order't'o prevent the tool from breakingin event. of its meeting .an unusual obstruction as it passes through the blank.

This spring support is attained in the present case by making the holder U-shaped.

' From the foregoing it will be seen that the Yso ing support.

tool has a fixed plane'of movement while it' is moved toward and away from the center of'movement of the spindle 4: by the stationary cam. v 4

In Fig. 8 is shown a cam having a cam groove which is slightly larger in diameter than the one shown in the other figures. It will be seen that the portions connecting the curved ends have been very slightly altered owing to the changed diameter of the larger end of the cam-groove.

The work-holder for supporting and mov-' ing the blank toward and away from the cutting tool will now be described. After .the'sides and periphery of the blank 12,

which may be a disk, a plate or a ring, or segment thereof, have been machined, it is mounted on the rotatablesupport 2% which in turn is carried by the sliding carriage 25 'through the medium ofthe stud 26, the arrangement being such that the Work is presented edgewise to the cutting tool. The blank is retained in place on the support by suitable screws or clamps 45. The under side of the rotatable support is provided with a hub that rests on and is supported at a fixed vertical height by the sleeve 27.

The sides of the'stud 26 are straight and" furnish a substantial bearing for the rotat- The lower end of the stud is shouldered and is retained in place on the carriage by a nut 28. The carriage travels back and forth on guides or ways 29, and is prevented from lifting and twisting by the L-shaped pieces 30, that engage with the projecting flange on the bed The support-24 consists essentially of a ring having a shoulder formed on-the periphery, which shoulder preferably forms a working fit with the inner wall of the wheel blank 12, in order to prevent displacement to the desired position by placing a thin ring or rings between it and the support. In-order to provide for blanks of varying thicknesswhere only a single revolving support is provided, the shoulder may be made deep enough to rece-ive 'the thickest blank designed to be cuton the machine, and shims made of rings employed to raise the thinner rings to the desiredheight. Such a con; struction is shown in Fig. ,9, wherein 1'2 represents the blank, 24 the revolving support, 46 the shims, the latter being circular so as to afford a firm support for the blank at all points, and 45 the bolts that hold the blank and shims in place. v

The automatic movements of the carriage toward and away from the cutting tool are controlled in the following manner. Mountedon the front of the bed in suitable bearings is a screw 31 of relatively low pitch which is driven by the spindle -l through suitable speed reducing gearing 32' The carriage is connected to the screw by a pair of movable jaws 33 (Fig. 3), and'these jaws are under the control. of the handle 34. \Vhen the handle is in the raised position (Figs. 1 and 3), the jaws are disengaged from the screw, but'when the handle is lowered, the jaws engage the screwandthe,

movements of the carriage are controlled thereby. In order to move the carriage manually toward and away from the cutting tool, a rack 35 is secured to the under side of the front flange of the bed, and' engaging therewith is a pinion 36 which is rotated y the handle 37 (Fig. 1). The manual control can be utilized only when the auto-' M matic feeding devices are disconnected from the carriage. The principal strain on the rotating support 24 1s 111 a downward dlrection and at the point where the cutting tool f 11' engages with the blank, and in order to furnish additional support therefor, a

special or auxiliary supporting device is provided. In the present'arrangement this support comprises a post 38 having at its upperend a pro ection which engages with the circular groove formed in the under side of the rotating support. The lower 'end of the post is enlarged, and rests on the inner guides or ways 011 the bed 1. The post is prevented from rising and twisting by the clamps 39, Fig. 3, that engage with the inner flanges on the bed. In order to insure corresponding movements of the post and 1'0- tating support, a plate 40 is bolted to the under side of the post and is clamped to the carriage by the'nut 28, whichlholds the stud 26in place. The post and carriage are *shown'as bemgmade of separatepieces and bolted together, but it is obvious that they being equal to the number of vanes on the wheel or; segment thereof. In bther words the support also forms an index wheel;- ,Mounted on the post'for engagement with the notches is a sliding piece 41 shown in dotted lines in Fig.- l. Extending laterally from said piece'is a projection 42 that enters a cam-grooveformed in the rotating" head '43. 'The head is provided with a bearing n is rotated by means of a-[pin the postang or similar. evice whic'h can be inserted in the holes formed therein. The support 24 and the blank are rotated by handuntil one of the notches in the index wheel coincideswithfthe sliding piece 11, after' ivhich.the'

head 4:2'i's rotated in a manner to move said piece upward and lock the parts in place. a

In'. the present instance the turbine wheel blank is horizontally supported on the ma-' chine, but where the wheels are'large they may be mounted vertically, in which case thefeam-groove 17v would have its greatest length at right angles to that shown, so that the tool will make its out substantially at right'angles to the one shown.

Assuming that a blank wheel of any suitable diameter is mounted on, its rotating support and the' carriage connected to the screw: power is then applied to the driving spindlel which causes the'head 5'to' rotate continuously and carry with it the. 7 tool ll and the screw 31, feeds the carriage forward. As the head rotates.the roller 19 carried by the support 18 travels inthe camgroove 1 and causes-thesupport 22, tool support 23 and tool 11, to move toward and away from] the center. of rotation of the spindle 4, thereby following a path of varying radius. When the roller, is moving in art of the cam-groove which is concentric with the center of movement of the head, the tool 11 will be cutting the curved portion of the passage in the blank, but as soon as it reaches a non-concentric point,the lateral movement of the tool, arranged to keep the tool outjiof engagement with the blank,

- commences. The straight port-ions of the motion due to the cam 13, which causes it to vanes are cut when the cam roller is passing from the concentric to the non-concentric portion of the cam groove. It will be seen that the tool has two motions, first an orbital move toward and away from the axis. of rotation of the driving spindle, and, second, a rotating motion due to the rotation of the spindle. It is by a combination of these two the invention can be carried out by other motions that the flattened ends'of the buckets are produced. --The tool enters the work obliquely and moves forward in a straight line until it reaches the point. indicated by the dotted -l ine"9, when 'it changes to a curve and continues vto the second dotted line 9, after which the path becomes straight again and the tool' leaves the work obliquely," but t e leaving angleis opposite the entering angle- As soon as the roller reaches the extreme; right-hand portion of the camgroove, the tool starts back, and when the properpoint is reachedit will again turn -downward and-pass through the blank and again cut away a certain amount of metal. As the cutting proceeds by successive steps, the carriage and blank are automatically fed forward until the desired depth of groove is l attained, after which the carriage is disconnected from the screw, moved backward by hand and the blank adjusted to a new position and the action repeated.

In accordance with the provisions of the patentjstatutes, I have described the principle of operation of-my invention, togetherwith the apparatus which I- now believe to represent the best embodiment thereof; but 'I desire'to haveit understoodthat the apparatus shown is only illustrative, fand that means. i I v I What I claim as new and deslre to secure by Letters-Patent of the United States, is,

- 1. In amachine of the character described, the combination of awork-holder which presents the surface of the'wo'rk to be cut edgewise to the tool, a tool for forming" the slots by successivecuts, a. tool'hold er, a meansfor rotating thetool-ho'lder, and ameans for imparting an orbital motion to the tool-holder, the tool being arranged to pass'through' the work in the direction of the widthof the bucket, whereby. it is maintainedout of engagement with the wor during a part of each revolution 2. In a-machine'of the character tool-holders being located in planes substan 'tially atright angles to'each other, means "for continuously rotating the.tool-ho1der. in

one direction, thereby causing it to pass through theperipheral face of the blank, and means for'moving the tool and its holder laterally with respect tothe work during the idle portion of its stroke soas to clear the work and return to an operative position;

'3. In a machine of the character described, thecombinationof a tool forforming the passages by a succession of cuts, a toolholder, a shaf for rotating thetool-holder,

v described, the combination of a work-holder which ;a support which holds the blank in a plane atright angles, or, substantially so, to the path of movement of the toohholde'r, and a cam'which imparts an orbital motion to the tool-holderat substantially right angles to the plane of the work so that the tool will clear the work during a portion of its stroke. 4. Ina machine for cutting curved slots in the edge of metal blanks, the combination of a tool arranged to form the passages port which presents'the blank 'edgewise to the tool and at right angles to the tool, or substantially so, and means for locking said support While the tool is cutting. i

5. In a machine of the character described,

the combination of atool,-a tool-holder, a

, pivotally supported head which carries the holder, a cam for causing the pathof the tool to vary from a true; circle, said cam constructed and arranged to cause the tool to enter and leave the workon a path of large radius and to travel in a path of difierent curvature while passing through the center portion of the work, a work-holder which sup orts the work in a plane substantially at right angles to that of the tool and presents the blank edgewise to the tool, and

means for feeding the .tool and work-holder .with respect to each other,

6. In a machine of the character described,

the combination of a driving spindle, a head mounted on the spindle, a tool-holder mounted on the head and'eccentrically disposed with respect toits axis, a cam for I causing the path of the tool to vary from a true circle, said cam constructed and arranged to cause the tool to enter and leave the work on a path of large radius and to travel in a path of smaller curvature while passing through the center portion of the work, a stationary abutment on the head, a

spring engaging the abutment for forcing v.

the holder into engagement with the cam surface, and a work-holder which presents the work edgewise to the cutting tool.

7. In a machine of the character described,

the combination of a driving spindle, a tool driven by the spindle and eccentrically mounted with respect to its axis, a means for causing the path of the tool to vary from a true circle, said means constructed and ar-, ranged to cause the tool to enter and .leave the work on a path of large'radius and to 'travel'in a path of smaller curvature while passing through the center portion of the work, a carriage for supporting the work, .a means for moving the carriage toward and away from the tool, and automatic means i ing head, a tool-holder carried by the head,

a means for causing the path of the tool to vary from .a true c1rcle,.sa;1d means constructed and arranged to cause the tool to enter and leave the work on a path of large radius and totravel in a curved path ofsmaller radius while passmg through the center portion of the work, a work-holder which presents the work edgewise to the tool, a carriage for moving the work-holder,

automatic mechanism for feeding the'carriage and work with respect to each other,

and' means for throwing the mechanism into and out of action.

9. In a machine of the character described, the combination of a rotary toolholder, a work-holder, the axesof said holders lying substantially at right angles toeach other, a cutting toolmounted in the toolholder, means for imparting angular movement to the tool-holder, means for causing the path of the tool to vary from a true circle, said means constructed and arranged to cause the tool'to enter and leave thework on a path of large radius and to travel in a path of smaller curvature While passing through the center portion of the work, and means for guiding the tool and tool-holder in their movements toward and away from their axis of movement. I

10. In a machine of the character described, thecombination of a cutting tool, a holder therefor, means for movin said toolholder about a given axis, means %or causing the path of the tool to vary from a true circle, said means constructed and arranged to cause the tool to enter and leave the Work on a path of large radius and to travel in a curved path of smaller radius while passing through the center portion of the work, guides forthe tool-holder, a work-holder, and means for raising and lowering the work with respect to, the center of movement of the tool.

11. In a machine of scribed, thecombination of a tool, a spring holder for the tool, a head for supporting and moving the tool about a given axis, and a means for causing the path of the tool to .vary "from, a true circle, said means constructed and arranged'to cause the too'l'to enter and leave the work in a path of'large radiusand to travel in, a curved path of (ilf ferent radius while passing through the center portion of the work. Y

12. In a machine of the character described, the combination of a tool, a "rothe character detatably mounted holder therefor, a driving means for imparting angular movement to the holder, 21 means for causing the path of the tool to vary from' a true circle, said means constructed and arranged to cause the tool to enter and leave the work on a path of large radius and to travel in a curved path of smallerradius while passing through the center portion of the work, a Work-holder, and an auxiliary support for the Work situ-- ated near the point of cutting.

13. In a machine of the character described, the Combination of a rotatable workholder, a rotary tool-holder, the axes of said holders lying substantially at night angles to each other,- a cutting tool mounted in the too1-holder and eccentrically disposed with respect to the axis of rotation of .the holder, 2

means for rotating said tool-holder, and means for causingthe path of the tool to vary from a true circ1e, -said:means corn structed and arranged to cause the tool to enterand leave the Work on a path-of large radius and to travel in a path of smaller curvature While passing through the center portion of the Work. y p

In Witness whereof, I- have hereunto set my hand this twenty-first day of January,

HENRY GEISENHONER.

WVitnesses:

BENJAMIN B. H LL, BERTHA SECOR.

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