US2656651A - Abrading machine - Google Patents

Description

Oct. 27, 1953 H. N. SEYFERTH ABRADING MACHINE 7 Sheets-Sheet 1 Filed Oct. 10, 1950 I N VEN TOR. Ha r0 2d h. fifyferth Oct 27,1953 H. N. SEYFERTH ABRADING MACHINE 7 Sheets-Sheet 2 Filed Oct. 10, 1950 INVENTOR. Harold )7. \S yferth 1 WWI 4f;

Oct. 27, 1953 H. N. SEYFERTH.

ABRADING MACHINE 7 Sheets-Sheet 3 Filed Oct. 10, 1950 \M D V \N lnuentar Hamid l7. S cyferth (2% Q ""52 8.

vmw

Oct. 2"], 1953 H. SEYFERTH 2,656,651

, ABRADING MACHINE Filed Oct. 10, 1950 7 Sheets-Sheet 4 HIH IIIII IIIIIII 1 INVENTUR. Harold D. .S ferih M. y ,M/W

Oct. 27, 1953 H. N. SEYFERTH 2,656,651

ABRADING momma Filed Oct. 10, 1950 7 Sheets-Sheet 5 INVENTQ Hamid I7. yf h Oct. 27, 1953 Filed Oct. 10, 1950 H. N. SEYFERTH ABRADING MACHINE 7 Sheets-Sheet 6 Oct. 27, 1953 H. N. SEYFERTH ABRADINC MACHINE 7 Sheets-Sheet 7 Filed Oct. 10, 1950 Patentecl Oct. 27, 1953 ABRADING MACHINE Harold N. Seyferth, East Detroit, Mich., assignor to Ex-Cell-O Corporation, Detroit, Mich., a corporation of Michigan Application October 10, 1950, Serial No. 189,372

13 Claims. 1

The invention relates to machines for finishing workpieces having complex curves surfaces, and it is more particularly concerned with machines in which the finishing is effected by the abrasive action of a tool on the workpieces.

The machine of the present invention, while capable of finishing workpieces of a wide variety of shapes, is particularly well adapted for finishing turbine blades that have been previously machined to the desired shape and approximately the finished dimensions by a machine such as that disclosed in my copending application Serial No. 189,371, filed October 10, 1950. In the machine referred to, the blade is shaped by taking a series of closely spaced longitudinal cuts with the spacing of the tool and work controlled by cam means so as to generate the desired surface contour.

The primary object of the present invention is to provide a machine by which the tool marks and excess stock left on the workpiece in the shaping operation can be removed quickly and efficiently to produce a finished turbine blade precisely dimensioned and smoothly finished.

Another object is to provide an improved turbine blade finishing machine which reduces loading unloading time, as well as operating time, thus enabling the blades to be produced quickly and at minimum cost.

Still another object is to provide a machine for finishing curved surface workpieces arranged to employ a novel cam having a surface of revolution completely free of abrupt rises or falls and capable of being produced easily and cheaply from a master pattern, exhibiting the surface to be reproduced.

A further object is to provide controls for machines of the above general character which renders their operation substantially automatic.

Qther objects and advantages of the inventionwill become apparent from the following detailed description of the preferred embodiment illustrated in the accompanying drawings, in

g which:

Figure l is a perspective view of a machine embodying the features of the invention.

Fig. 2 is a perspective view of a typical article adapted to be finished by the machine, the article being a turbine blade.

Fig. 3 is a sectional view taken in a vertical Fig. 5 is a fragmentary elevational view of the machine as viewed from the left end.

Fig. 6 is a fragmentary plan view of the outer end of the work holding spindle and the controls associated therewith.

Fig. 7 is a fragmentary elevational view of the machine as viewed from the right end.

Fig. 8 is a sectional view taken in offset planes substantially on the line 8--8 of Fig. 7.

Fig. 9 is a sectional view taken in a vertical plane substantially on the line 9--9 of Fig. 7.

Fig. 10 is a diagrammatic view showing the relative positioning of the tool and workpiece.

Fig. 11 is a schematic diagram of the hydraulic circuit of the machine.

Fig. 12 is a schematic diagram of the elec trical circuit of the machine.

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawings and will describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions and uses falling within the plane through the axis of the work holding spindle and showing the tool slide in elevation.

Fig. 4 is a sectional View of the work supporting frame with the tool slide, the work holding spindle and associated elements shown diagrammatically.

in the appended claims.

Referring to Figs. 1, 3 and 5 of the drawings, the exemplary machine comprises a generally rectangular box-like base 20 from which rises an upright frame including a pair of end members 2| and 22 joined adjacent their upper ends by an inwardly offset vertically disposed web 23. Extending between the end members below the web is an inclined apron 24 which serves to direct metal chips and liquid coolant through an opening 25 in the top wall of the base 20 into a compartment or sump within the base.

Supported on the machine frame at the front thereof is a tool spindle and drive assembly 26. This assembly may be of conventional construction and, as shown more clearly in Fig. 3, comprises a base member 21 bolted or otherwise suitably secured to the web 23 of the frame. The basemember 2! is formed with suitable ways for supporting and guiding a slide 28. at the upper end of which is journaled a rotary spindle 29 which projects at one side of the slide and carries a suitable abrasive tool, in. this instance a grinding wheel 30; Also mounted on the slide 25 is a motor M arranged to rotate the spindle 29 at high speed through the medium of a driving belt 3!. As shown in Fig. 1, the belt and associated rotating elements are enclosed in a coolant and chip-proof guard 32.

While as indicated above the exemplary machine is shown equipped with a rotary grinding wheel, it will be appreciated that other types of abrasive tools such as abrasive belts or the like may be employed if desired. When equipped with the type of tool illustrated, the spindle and drive assembly 26 is mounted so that the slide 28 is adjustable in an inclined-but generally ver tical path for varying the effective height ofthe. wheel 3%. The spindle 29, in this instance, is arranged transversely of the path of adjustment: so that its axis is in intersecting right angularly disposed planes, one of which is vertical and the other inclined to the horizontal. The-wheel 3,0.- 15% mounted at the upper end of; this. spindle; in a.

position so as to tangentially engage the surface of the work and through adjustments of the slide. compensation may be made for tool-s of different diameter.

Adjustment of the spindle slide 28 is effected in the present instance by means of a feed screw (not shown) adapted to be rotated. by a hand. wheel 34 located adjacent the lower edgeof the basemember 2i or alternatively by a handwheel. 35 located adjacent one side of the base mem -.v her. As shown in Fig. 3.. the spindle and drive assembly isequipped with a wheel truing. dresser 38 which may be similar to that disclosed in the patent to Gilbert D. Stewart, No. 2,351,159, issued. June 13, 1944. Mechanism similar to that disclosed ha the patentto M. A. Mathys, No. 2,310,977, issued February 16, 1943, may be provided for automatically adjusting the position of the grinding wheel after each truing action. As the dresser and adjusting mechanism form, no. part of the present invention, it is not believed necessary to describe. them in detail, but. referonce may be had to the above noted patents for a description. of their construction and mode of operation.

For supporting a workpiece W in operative. relation tothe grinding wheel 30, an. auxiliary frame 49 is mounted at the top. of the machine frame for oscillating or pivotal movement about a horizontal axis and for linear translation along said axis. Provision is made for holding the workpiece abovethe wheel 30 so that they pivotal; movements of the frame Ml are effective to. move the. work toward or from the wheel and thus determine the depth of. cut, that is, the amount of stock removed by the wheel. Rotation of th workpiece together with the traverse movements of the frame serve to present the entire work surface to the action of the wheel. To enable the machine to remove surface irregularities and excessmaterial from the workpiece and produce a finished piece of precisely the desired dimensions, provision is -madefr rocking the frame on itspivot to vary the relative positions of the tool and work in timed relation to. the rotation of the workpiece and its linear translation with the frame. v 7

Referring to. Fig. 2 of the drawings, the turbine blade W illustrated is typical of the type. of work that can be finished by the machine of the in-- vention. It has a transversely disposed root portion 4| shaped for mounting in a dovetailed slot and a blade portion 42 which is convex on one side and concave on the opposite side. The blade portion conventionally has relatively sharp leading and trailing edges and it may be twisted about its longitudinal axis to present a generally spiral configuration. V

For machining purposes, the blade is initially formed with an integral lug 43 at the tip end and this lug center drilled for the accommodati n 0f a tail center which assists in accurately locating and supporting the blade during the machining process. The lug and the adjacent unfinished portion of the blade is cut off at a later stage of the manufacturing process.

Referring now to Figs. 3-5 of the drawings, the auxiliary frame 49 comprises an elongated top member 45* having depending flanges 4B and 4'! at opposite ends. Support for the frame is provided by bearings 48 and 49 seated in the legs 46 and .41 and respectively engaging over opposite ends of an elongated rod 50. The rod 50 extends axially. through acylinder 5| formed in a bracket 52, rigidly. supported on the rear portion of the machine frame. A piston 53 is fixed to the intermediateportion of the rod 50 within the cylinder. The opposite ends of the cylinder are closed by heads 54 apertured for the passage of the projecting ends of the rod so that the piston may be; shifted back and. forthwithin the cylinder by introductionof. pressure fluid alternately into 0 p posite ends of the cylinder. At least one of the bearings. 48, 49 is confined against movement axially of the rod 5.9 so that the auxiliary frame 40 is constrained to, reciprocate with the rod.

Thebearings 48. and 49 in addition to afford ing an operative connection between the piston rod 56, and the auxiliary frame 40, also. serve asv trunnion bearings permitting the frame to pivot about the axis of they rod. Preferably this axis is located adjacent therear edge of the auxiliary frame so that the weight of the frame tends to rock its forward portion downwardly or toward the tool spindle 29 which it overlies.

Referring now to Fig. 3 of. the drawings, it will be notedv that a depending flange or web 55 is. provided on the underside of the top member 45 in parallel spaced relation to the end flange 46. These two flanges provide support for a rotatable worl; holding spindle Eli disposed with its axis parallel to. and offset forwardly from the pivotal axis of theauxiliary frame.

In the exemplary machine the spindle is formed. at its inner end with an enlarged head 6|. iournaled in a bearing 62 seated in the flange 5 5, The other end of the spindle extends through a sleeve, member 6.3. journaled in a suitable bearing seated in the flange 46.

The head portion 6! of the spindle is formed with an axial recess 91 socket 6 adapted to receive the shank portion of a chuck 65 which may be locked in place as by a set. screw 66. The chuck 65 may be, of the conventional type having oppdsfid, jaws operable. to grip or release a work-, piece. Actuation of the jaws is effected through the medium of a. rod 6] extending through an axial bore in. th ndle and roj ct at h outer end thereof. A knob 68 on the projecting end is available for manipulation of the chuck. .In the particular embodiment of the invention i1.lustrated,v the Work ol g p d is 1 rotatably coupled with the sleeve 53 as by a feather key 1'0 permitting relative axial move: ment of the parts. A coil spring H interposed between a shoulder '12 on the spindle and an opposed shoulder on the sleeve member urges the spindle to the right as viewed in Fig 3.

The axial positioning of the spindle is deter.- mined by an annular cam it supported on the outer side of the flange 46 coaxially of the spindle 60 and having an axially facing bearing surface 14. This surface forms a track for a follower roller 15 journaled on a stud l6 projecting radie ally from a collar Tl rigidly fixed to the spindle.

With this arrangement the spindle is adjusted axially incident to its rotation as determined by the contour of the cam track 14.

In loading the workpiece W into the machine the root portion 4| is gripped in the jaws of the chuck 65. For supporting the other end of the workpiece there is provided a tailstock 88 having a center 8| engageable with the lug 43. The tailstock 80 may be similar in construction to that shown in my copending application above referred to. For present purposes it is sufficient to note that the center 8| is carried by a slide 82 supported for movement axially toward and from the workpiece. The slide may be shifted manually as by a hand lever 84 (Fig. 3) or by a pressure fluid operated actuator including a piston 85 operating in a cylinder 86 formed within the bracket 83.

To regulate the position of the work relative to the tool 30, that is, the radial distance of the peripheral or operating surface of the tool with reference to the axis of the workpiece, as the work is rotated and shifted axially relative to the tool, cam means is provided for rocking the frame 40 about its pivotal axis. The cam means includes a barrel type cam 90 having a surface of revolution 9| generated in conformity with a master pattern so as to represent the finished contour of the workpiece. Cam 90 is formed with an axial bore 92 adapted to slidably receive the work holding spindle 60 and is nonrotatably secured in fixed angular relation to the spindle by a dowel pin 93 carried by a collar 94 keyed to the spindle. A nut 95 threaded on the spindle and bearing against the end of the cam 90 remote from the collar 94 holds the cam securely against the collar and against axial movement relative to the spindle.

For cooperation with the cam 90 a follower roller 96 is mounted on the machine frame directly below the cam. As shown in Fig. 3, the follower roller is supported for rotation about an axis parallel to the axis of the work holding spindle adjacent the upper end of a slide 9! supported and guided in a bracket 98 bolted or otherwise rigidly secured to the frame member 2| of the machine. Provision is made for adjusting the vertical position of the follower roller as required for tools of different diameters. For this purpose a stop screw 980. (Fig. 4) threaded into the lower end of the slide 91 has its head positioned to engage a shoulder or abutment 99 formed on the bracket 89. The screw may be provided with a hand wheel I for convenience of manipulation.

Power actuated means is provided fors'ffif'ting the slide 91 and follower roller 96 upwardly to raise the work supporting frame to a retracted position for convenience of loading and unloading the work. This power means also serves to control the rate at which the frame 40 is lowered to feed the workpiece to the tool. As shown in Figs. 3, ,4 and 11, the power actuated slide shifting means comprises a piston l0! working in a vertically disposed cylinder I02 formed in the bracket 98 below the abutment 89. The piston has a rod I03 projecting'from the upper end of the cylinder and operatively secured in a suitable manner to the lower end of the adjusting screw 98. Introduction of pressure fluid into one or the other end of the cylinder 182' will .70 accordingly raise or lower the frame 48 by pivotsented to the tool.

6 the preceding operation. As the tool marks left by the milling operation extend longitudinally of the workpiece the preferred relative traverse is effected by rotation of the workpiece about its longitudinal axis. Provision is therefore made for for rotating the work holding spindle to effect such relative traverse while the work is shifted axially as by linear traverse of the frame 40 to present successive areas of the workpiece for the action of the tool. In practice these two movements are coordinated so that the tool, in effect, describes a spiral path around the work extending from one end to the other of the surface area to be finished.

Rotation of the spindle 60 is effected in the present instance by a motor MI supported at one end of the frame 40. As shown in Fig. 5, a gear I04 on the motor shaft meshes with a pinion I eyed to a shaft I06. The shaft is journaled in a housing I01 which encloses the spindle supporting sleeve 53. As shown in Figs. 3 and 4, a worm I08 on the shaft cooperates with a worm wheel I 06 keyed to the sleeve 63 to complete the driving connection.

Preferably the motor MI is a. variable speed motor capable of driving the shaft I08 at at least two different speeds. For example, when operating on relatively flat surfaces it is desirable to traverse the work relatively slowly past the tool, whereas a much faster traverse is desirable when the narrow edge of the workpiece is pre- Motor speed may be conveniently controlled by a control device such as a two position switch LS4 actuated in timed relation with the rotation of the spindle 68. For actuating the switch LS4 a control member or disk H0 (Figs. 4 and 5) is keyed or otherwise nonrotatably fixed on the projecting end of the spindle 60. Arcuate shoes I09 supported on the outer face of the disk H8 engage the switch to close switch contacts LS4A for operating the motor at high speed. When the shoes are rotated out of engagement with the switch, contacts apart as shown in Fig. 5.

The invention also provides novel control 'mechanism whereby complicated curved areas such, for example, as the fillet F joining the root portion 4! and blade portion 42 of the blade may be finished with great precision. The peculiar tool and work movements required for such finishing will be appreciated when it is considered that the fillet in addition to following the general contour of the blade. portion, also follows the transverse alinement of the root portion. To impart the movements to the workpiece so as to engage the work and tool along this path, there is provided a work frame positioning cam H5 which supplements the spindle positioning action of the cam 13.

The cam H5 which is generally wedge shaped is interposed between an abutment or anvil H5 mounted on the flange 4I of the frame land a stop element H1 mounted onan upstanding bracket H8 rigid with the machine frame. As shown in Fig. 8, the face of the cam engaging the anvil H6 is flat while the opposite face is contoured to provide an inclined area I Hi, a sub *Staintially flat dwell area I20, 2. second inclined area III and another flat dwell area I22.

the frame 40 is urged to the right this cam surface engages the stop which thus determines the limit position of the frame. As the cam is withdrawn, the frame is allowed to advance slowly to the right and then is maintained in this position for an interval of sufficient length to permit a complete revolution of the workpiece. A further advance occurs as the inclined area IZI rides over the stop and there is a further dwell as the area -I22 engages the stop. This latter dwell is preferably also of suflicient length to permit a complete revolution of the workpiece. The movements of the table occasioned by the cam IIS combined with the axial shifting of the work holding spindle 60 by-the cam l3-enable the tool to follow and accurately finish the fillet F entirely around the blade.

For retracting the cam I I in the manner above described, there is provided a pressure fluid operated actuator comprising in this instance a cylinder I23 supported on the flange 41 adjacent one end of the cam. A piston I24 working in the cylinder has a piston rod I25 formed at its outer end with a T-shaped head I26 engageable with a T slot I21 in the adjacent end of the cam. By introduction of pressure fluid into one end or the other of the cylinder I23 the cam may be shifted in either direction as required. The supply of pressure fluid is controlled by a solenoid operated valve VI with which is associated a metering valve MVZ as shown in Fig. 11.

The pressure fluid operated actuators hereinbefore referred to are incorporated in a novel hydraulic system including suitable control valves and electrical operating and control devices for effecting operation of the machine in a completely automatic cycle. Pressure fluid for operating the actuators is supplied by a pump P driven by an electric motor M2. As shown in Fig. 11, the pump draws fluid from a sump or reservoir R by way of an intake conduit I30 and discharges it by way of a working pressure relief valve PRV to a branched pressure line I3 I. The pressure fluid is distributed to the various actuators under the control of valves whose operation can be best'described in conjunction with a de-- scription of the electrical control circuits shown in Fig. 12 ofthe drawings. This control system ispreferably operated at low voltage, operating current being obtained in this instance from a step-down transformer T having its primary winding connected across two of the leads of a three wire power line L which supplies current to the motors M, MI, M2 and M3. A switch S is provided in the power line L for shutting off all power to the machine when desired.

. MRI-2 to connect motor M across the line L.

Assuming that the machine is in a rest condition, thework supporting frame will be at its right-hand limit position with the frame raised 'to unloading position 'through the action of'the actuator for the follower roller slide 91. The workpiece is accordingly loaded in the machine by placing the root portion in the chuck 65 and closing the chuck jaws by operation of the knob 68. Cycle selector switch CS is set manually in the automatic position in which it is shown in Fig. 12 with its upper set of switch contacts CS-I open and its lower set of switch contacts CS-2 closed. Direction control DS switch is now set in its right position opening switch contacts DS-I and closing contacts DS-Z.

Limit switch LSI is actuated as a result of the preceding movement to starting position so that switch contacts LSI--A open and switch contacts LSI-B are closed. Limit switch LS2 is held open by engagement therewith of a pin I32 cammed by the control disk III] and LS3 is held open by a stop member I33 fixed to the piston rod 50 (Fig. 4). Limit switch LS4 is engaged by one of the shoes III on the disk IID closing switch LSl-A and opening switch LS I-B. Limitswitch LS5 has" its switch contacts LSEi-A open and switch contacts LS5-B closed due to the switch actuator I34 being in a raised position. This actuator is carriedon'an extension I35 of the lower end of the work frame camming piston II.

I An automatic cycle may'now be initiated by momentary closure of cycle start switch (IS-3. Closure of this switch completes an energizing circuit for control relay CRI which completes a holding circuit for itself by closing switch CRI-I. Switch CRI-Z is closed to complete an-en'ergizing circuit for solenoid SV3 which shifts valve V3 to direct pressure fluid into the upper end of the cylinder I82. This pressure fluid circuit extends by way of conduit I40 which branches from the pressure line I3I, conduit I4I, valve V3, conduit I42, metering valve MVI and conduit I43 to cylinder I02. Metering valve MVI includes an adjustable orifice member I44 which determines the "rate of flow of fluid to the cylinder and. thus the rate of descent of the work supporting frame Itmay be appropriate to note at this point that when valve V3 is shifted to its alternate position by the biasing spring I45, cylinder I02 is connected to the drain I45 by way of the conduit I43 and through a check valve I46 in metering valve MVI, conduit I42, valve V3 and conduit I41 which is a branch of the drain I45. The metering orifice is thus by-passed so that the upward movement 'of the piston IUI and the work supporting frame is effected at a rapid rate.

Closure of switch CHI-3 completes a circuit by way of limit switehLS4-A for motor relay MR2 which closes switch MRZ-I to connect the 'LSfi-B interrupts the circuit' for infeed cam solenoid SV2 and the closure of limit switch Lsfi -A completes an energizing circuit for outfeed cam solenoid SVI. ,The latter solenoid energi zes and shifts valve VI to direct pressure fluid to the inner end of the cam actuating cylinder IZS 'PressurefIuid flow is by way of a'conduit I48 branching'from the pressure line 'I3I, valve 9 VI and conduit I49 extending to the inner end of the cylinder I23.

Fluid exhausted from the opposite end of the cylinder I23 is discharged by way of a conduit I50, metering valve MV2, conduit II, valve VI and conduit I52 to drain I45. Fluid thus discharged is directed through a metering orifice defined by an adjustable member I53 which restricts the rate of flow and thus limits the withdrawal movement of the cam to a predetermined desired speed. The movement of the cam in the opposite direction is effected at a higher rate by reason of the by-pass around the orifice afforded by the check valve I54.

In finishing the particular workpiece illustrated, the metering valve is set to effect a withdrawal of the cam H5 at a rate such that the stop member I I7 rides down the inclined surface H9 and engages the dwell I substantially as the Work is brought into operative engagement with the tool. The dwell I20 is of sufficient length to permit the work to make a complete revolution wherein the fillet F is finished with the cam I3 cooperating in positioning the work with respect to the spindle. The stop then rides down the inclined surface I2I and engages the dwell I22 which also is of sufficient length to permit a complete revolution of the work.

Shortly before the cam H5 is shifted far enough to disengage the stop from the dwell I22,

the actuator piston I24 uncovers a port connected by a conduit I55 with direction valve DV. The plunger of the valve DV is shifted to the left so as to direct pressure fluid through the conduit I56 to the right end of the cylinder 5I and thus initiate feed of the work supporting frame to the left. The workpiece is therefore traversed longitudinally relative to the tool and at the same time is rotated continuously by the motor MI. As described heretofore, the motor speed is regulated in accordance with the requirements of the particular surface area being finished by alternate operations of the limit switches LS4-A and LS4-B.

Fluid flow to the cylinder 5| is by way of the conduit I40, branch conduit I51, valve DV and conduit I56. Fluid is exhausted from the other end of the cylinder by way of a conduit I 58, metering valve MV3, conduit I59, metering valve MV4, conduit I60, valve DV to drain I45. Metering valves MV3 and MV4 are respectively fitted with adjustable orifice members I6I and I62. In the present setup the orifice member I62 is adjusted to provide a relatively slow feed properly coordinated with the rotative speed of the work to enable the tool to operatively engage the entire area of the workpiece. Orifice member I6I which is set for a substantially higher rate of feed has no effect upon the operation of the machine in this particular cycle.

Movement of the work frame 40 to the left continues until the tool reaches the end of the surface being finished, at which time limit switch LSI is actuated to open normally closed contacts LSI-B. Actuation of the limit switch may be efiected in any suitable manner as an incident to the table approaching its limit position as, for example, by means of a stop element I65 fixed to the spindle 50, as shown in Fig. 4. With limit switch LS I-B open the next opening of limit switch LS2 by the pin I32 on disk I I0 as the work is rotated to an unloading position results in the deenergization of control relay CRI. Relay CRI open switch contacts CR I -2 deenergizing solenoid SV3. This permits the valve V3 to shift under spring actuation to its table raising position, wherein the upper end of the cylinder I02 is connected to drain, thus allowing the piston IOI to raise the table rapidly to the unloading position. The opening of switch contacts CHI-3 interrupts the circuit for either of the motor relays MR2 or MR3 which may be energized at this time. As a result the work spindle driving motor MI is stopped.

Switch contacts CRI- I are also opened, deenergizing solenoid valve SVI. As the work frame 40 moves upwardly, limit switch LS5 is disengaged from the actuator I34 opening switch contacts LSE-A and closing switch contacts LS5-B. Closure of the latter switch contacts completes an energizing circuit for solenoid SVZ which shifts valve VI to direct pressure fluid to the cylinder I23 to effect inward feed of the cam I I5. As previously explained, such inward movement takes place at a rapid rate.

As the cam I I5 approaches its inner limit position, piston I24 opens a port connected by a conduit I66 with the direction valve DV, thus directing pressure fluid to the right end of the valve and shifting the valve plunger into a position to initiate feed of the work supporting frame 40 in the opposite direction or to the right. This movement takes place at a rapid traverse rate since the fluid flow to the left end of the cylinder is by-passed around the orifices I6I and I62 by way of the check valves I61 and I68 associated therewith. As the work supporting frame reaches its right limit position, limit switch LSI is actuated by the stop member I33 to deenergize control relay CRI. Deenergization of control relay CRI brings the machine to a complete stop with the work supporting frame in the raised position, so that the work may be unloaded and a new workpiece loaded therein.

At times it may be desirable to provide for rapid traverse movements of the work support ing frame 40 in the same direction as the feed movement. Under such conditions a limit switch LS3 is arranged for actuation by or in response to the movement of the frame to a predetermined position. Closure of switch LS3 energizes a sole.- noid SV4 which shifts a pilot valve PV to operate a valve V4 to its alternate position. Valve V4 when so operated establishes a bypass around the metering valve MV4 by connecting conduit I59 with conduit I60 by way of conduits I69 and I10. Upon opening of the switch LS-3 solenoid SV4 is released and the pilot valve is returned by a spring to reset valve V4 for feed operation.

The control system may be readily changed to adapt the machine to start grinding at the tailstock end of the workpiece rather than at the headstock end, as above described. To eifect such operation, the conduits I55 and I65 leading from the cylinder I24 to the direction valve DV are reversed. Additionally the direction selector switch DS is operated to the left position, closing switch contacts DS-I and opening switch con tacts DS-2. The driving motors are started in the manner heretofore described by closure of the motor switch MS and the cycle is started by closure of the cycle starting switch Cid-3. In this case, however, control relay CRI completes its holding circuit by way of switch URI-I, direction switch DS-I and a switch TRI closed by a delayed action relay TR. This relay is energized by closure of a limit switch LSI-A incident to the work supporting frame moving to its left-hand limit position. Operations then proceed in sub stantially the manner above described.

The control circuits may also be conditioned for manual control by operating the cycle control switch CS to its alternate position, closing switch CS-i and opening switch OS-rZ. When set for manual operation inward movement of the feed control cam H is initiated by closure of control switch CS4, Outward movement of the cam switch is initiated. by closure of control switch CS5. Automatic control of the cam is precluded by, the, opening of control switch CS6. Closure of control switch CS1 permits the work spindle drive me motor Ml. to be'started and stopped manual? 13!. by, closure of a switch CS8. To. permit, such operation, a manually settable. switch is first actua atcd tov the. manual control position, closing switch CS5. and opening swi h CS1 The. machine. may.- be. stopped at any time re-. eardless. of the settingof the cycle. selector switches by Opening a normally closed master stop switch SSE. Likewise, the. tool spindle mo r. may. be. stopped by: actuation. of a stopswitch SS2; and, when the. machine is set for automatic. operation, the cyclecmay be interrupted at any. time by, opening a. stop. switch SS3. In thelatter instance the cycle may be, restarted at the. point of; interruption by. momentary closure. of. con trol witch CS.3;.

It wili be. apparent from, the foregoing that the, invention, provides. abrading. machine of novel and advantageous character, particularly W ll? adapted; for. finishing, workpieces having complex curved, surfaces, The machine is easy toload, and. unload: and is rapid and eflicient inoperatiOn, Through. the. medium. of the novel operating. and control. systems incorporated in the machine, the manual labor involved in thefinishing. 0f. workpieces such. as turbine blades is practically. eliminated and the time required forfinishing such workpieces issubstantially-4 reduced. Overall costs ofrsuch. operationsare thus held; at; a low figure.

I.- claim as my invention;

1-, In a. machine. foi operating on workpieces haying. complex curvedsurfaces of revolution, in. combination, a base, a slide mountedon said base, a driven abrasive tool carried by said slide, a framesupported onsaidbase for pivota-Lmovement about an axisdisposedat-one side oh-said. tool. and: for-.linear translation along said axis, worleholding means onsaidframe spaced from its .pivotaliaxisso as topresent-a held work piece to the tool when the frame is rocked-dnone direction to. an operating position, a cam supported-.on. saidlframein axial alinernent' with the workpiece, said-cam. having asurface of-=revolution derived-from a pattern exhibiting the contountobereiiroduced; on the workpiece, a cam follower. on said base engageable b3 said cam, said -carn-and. foilower coacting to vary the; position. of: the workpiece relative to said-tool in accordance with said-contour, means for rotating said worlcholding means and said; cam in sy n-' chronisr'n, a pressure fluid; operatedactuator adapted whenjfi uid is supplied thereto to rock; said f rame from operating position to retracted position; said frame returning to operated position by gravity upon exhaustcf'iiu'id from the actuator, valve mechanism controlling the supplyiand, exhaust of fluid toand 'fromsaid; actuator, said .mechanis'm vincludinga metering valve operative to, control the.- exhaust of fluid from the actuatorandthereby regulate the. speed of movement of the frame; toward operating.- position,

andia checlg. valve. operative, to estabjlish a bye;

p d, eidmeie inavalve and permitrapide 12 movement of the frame toward retracted posi tion. a

2. In a. machine for'operating on workpieces having complex curved surfaces of revolution, in combination, a base, a slide mounted on said base, a driven abrasive tool carried by said slide, a frame supported on said base for pivotal moves ment. about an axis disposed at one side of said tool and for linear translation along said axis, work holding means on said frame spaced from its pivotal axis so. as to. present a held workpiece. to the tool when the. frame is rocked in one direction to an operating position, a cam supported on said frame in axial alinement with the workpiece, said cam havin a surface of: revolution derivedfrom a. pattern exhibiting the contour to be reproduced on the workpiece, a cam follower on said base. ene eeable by said cam, said. cam and followe coaoting to vary he position. f the. w rkp ece. relative to said tool in accordanc wi h said; con our, means for rotatin said: worl; holding means, and said cam in synchronisrn, power actuated; means for translating said: frame so as to traverse the workpiece and, cam axially relative to said tool and said rollower, and control, means inch; ing a. second cam, shiftable. in timed e a ion. to. the. rotation of said work; holding means for oordina ing. the rate; or movement of said frame with, the. liotative Speed aid 1 1 01 11 means 3-. In; a. machine for: nish n workpieces; hav e ompl x urved surf ce in. combinatiom a. ase, a driven abras ve. tool upported; on said. base, W011i; supporting means; mounted on. said: base fo mov me a dir ction; to. feed: the.

o k; o. and. tract t. from th tool: and; a. dis m t on t r rerseh worn past the tool, a.

n atiyc nc dcnt o; he; t tion. o said; pindlfi:

for imparting axial movements to the spindle; a. eco d; am norm l posit ned o b o k, aid WQii upp r i m ans; ag ins movem nt. by. aid-p wer actu tcdlmeans. and: an ctu or-t r;- w ih raW n "d seco d: amifroni;sa dzblpclsina ina har dmiper ntroll m i l ment he. work; sucportinsi mean uchiwithclr ali n ma hine o h. Q KQifiGGS.. iWr' om x: urs ssh urfaces; om-binati m. haemadrirenab i e oo supp rted ongsaid. means: m un on; aid: ionto .d-theworkla dr etrac i ti rom h ool -n adircctioir. o raverse tha -enemas. the 0 1;. a work; holdens indle. uppo ed: sa Work. snumrtina; means for rotatiop and; mo h m an r ota ing; aid: p ndles. newer actu t d. an r in ai i work; supnortinsr a d: rayere nadir ction; means;

' o. v hcs otati n of-sai.

limo emcntseto t esn nd cia.

4 ,ca slaeainstmovementby saidi new r: riu ted; eans. pressure fluid: peratedi mea o h ft ng: aid; s condi to; permit:

on ro l d movement f: said; Work; supportin -2 means b i aid p w. actuatedm ans.andicontroli means; cia ed:

for; rewlgtipgjherate;ofwvithdrawal;

a tion of aid: first came. and; therebyon imi ed; axiah more! pindle;

tn saidupressure fluidt-oper-l' 13 cause the tool to describe a predetermined path about the workpiece.

5. In a machine for finishing workpieces having complex curved surfaces, in combination, a driven abrasive tool, work supporting means including a frame swingable about an axis spaced laterally from said tool and for linear translation about said axis, a first power actuated means for swinging said frame between operating and retracted positions, rotary cam means for determining the operating position of said frame, a second power actuated means for translating said frame and said cam means, a, work holding spindle rotatably supported on said frame, a motor for rotating said spindle and said cam means, and control mechanism including control devices for initiating and interrupting the operation of said power actuated means and said motor for effecting in sequence the swinging of said frame to operating position, rotation of the spindle with the workpiece in operative engagement with the tool, translation of the workpiece relative to the tool, swinging of the frame to retracted position, and translation of said frame back to starting position.

6. In a machine for finishing workpieces having complex curved surfaces, in combination, a driven abrasive tool, work supporting means including a frame swingable about an axis spaced laterally from said tool and for linear translation about said axis, a first power actuated means for swinging said frame between operating and retracted positions, rotary cam means for determining the operating position of said frame, a second power actuated means for translating said frame and said cam means, a work holding spindle rotatably supported on said frame, a variable speed motor for rotating said spindle and said cam means, and control mechanism including control devices associated with said power actuated means for effecting in sequence the swinging of said frame to operating position, rotation of said cam means and said spindle with the workpiece in operative relation with the tool, and translation of the workpiece axially relative to the tool, said mechanism also including control means for periodically varying the speed of said motor in timed relation to the rotation of said spindle.

'7. In a machine for finishing workpieces having complex curved surfaces, in combination, means for supporting a workpiece for movement toward and from an abrasive tool, cam means controlling the position of the workpiece relative to the tool to determine the depth of cut taken by the tool, means for rotating the workpiece and said cam, means for imparting axial movement to the workpiece, and control mechanism for effecting in sequence rotation of the workpiece in engagement with the tool with the workpiece restrained against axial movement to cause the tool to describe a generally circular path :around the workpiece, and simultaneous rota- :tion and axial translation of the workpiece to cause the tool to describe a generally spiral path around the workpiece from one end to the other of the same.

8. A machine as set forth in claim 7 characterized by the provision of means in the control mechanism operative when the tool reaches said "other end of the workpiece to shift the workpiece out of engagement with the tool and to interrupt its rotation.

9. In a machine for operating on workpieces having complex curved surfaces of revolution, in

combination, a base, a slide mounted on said base, a driven abrasive tool carried by said slide, a frame supported on said base for pivotal movement about an axis disposed at one side of said tool and for linear translation along said axis, a work holding spindle on said frame spaced from the pivotal axis of the frame so as to present a held workpiece to the tool when the frame is rocked in one direction to an operating position, a cam supported on said frame in axial alinement with the spindle, said cam having a surface of revolution generated from a pattem exhibiting the contour to be reproduced on the workpiece, a cam follower on said base engageable by said cam, said cam and said follower coacting to vary the position of the workpiece relative to said tool in accordance with said contour, means including a variable speed motor for rotating said spindle and said cam in synchronism, power actuated means for translating said frame to traverse the workpiece and cam axially relative to the tool and follower, a pair of electrical switches operable selectively to effect operation of said motor at different speeds, a disk mounted on and rotatable with said spindle, and switch actuating elements carried by said disk for actuating said electrical switches at predetermined points in the rotation of said spindle.

10. In a machine for operating on workpieces having complex curved surfaces of revolution, in combination, a base, a slide mounted on said base, a driven abrasive tool carried by said slide, a frame supported on said base for pivotal move-' ment about an axis disposed at one side of said tool and for linear translation along said axis, 'a work holding spindle on said frame spaced from the pivotal axis of the frame so as to present a held workpiece to the tool when the frame is rocked in one direction to an operating position, a cam supported on said frame in axial alinement with the spindle, said cam having a surface of revolution generated from a pattern exhibiting the contour to be reproduced on the workpiece, a cam follower on said base engageable by said cam, said cam and said follower coacting to vary the position of the workpiece relative to said tool in accordance with said contour, means including a variable, speed motor for rotating said spindle and said cam in synchronism, power actuated means for translating said frame to traverse the workpiece and cam axially relative to the tool and follower, a pair of electrical switches operable selectively to effect operation of said motor at different speeds, a third electrical switch adapted when. actuated to stop said motor, a disk mounted on and rotatable with said spindle, and actuating elements for said switches mounted on and rotatable with said disk.

11. In a machine for finishing workpieces having complex curved surfaces, in combination, a base, a driven abrasive tool supported on said base, work supporting means mounted on said base for movement in a direction to feed the work to and retract it from the tool and in a direction to traverse the work past the tool, a work holding

Images