US2141596A - Automatic steady rest for grinding machines - Google Patents

Description

' 1933- G. CROMPTQN. JR

AUTOMATIC STEADY REST FOR GRINDING MACHINES Filed Nov. 19, 1956 2 Sheets-Sheet l 1938. G. CROMPTON. JR

AUTOMATIC STEADY REST FOR GRINDING MACHINES Filed Nov. 19, 1956 2 Sheets-Sheet 2 Y 0 W0 0: WV, f0 o 0 1 5 o/u 9 no 2 M6 w 3 m m 8 v7 7 @7 25 Other objects will be in part obvious or in part which fits usual dog 33 fastened to the shaft 30. 25

40 rests; feeding apparatus which may be of any desired 40 5 front elevation the base for one of the steadyand automatic actuating apparatus 5| for the 4,5

. 55 two slideway castings attached in position. ure 5, I may'provide'any suitable apparatus for 5 Patented Dec. 27, 1938 UNITED STATES PATENT OFFICE AUTOMATIC STEADY REST FOB GRINDING MACHINES George Crompton, Jn, Worcestei,'Mass., assignor to Norton Company, Worcester, Mass, a corporation of Massachusetts Application November 19, 1936, Serial No. 111,570 7 Claims. (01. Bi ses) The invention relates to steadyrests for grind- Referring first to Figure l, the invention may ing machines. g be embodied in or applied to a cylindrical grind- One object of the invention is to provide a ing machine, sometimes referred was a plain steadyrest system for a grinding machine faciligrinding machine, having a base casting l tating the grinding of shafts, especially long which, as shown in Figure 2, includes walls ll shafts. Another object of the invention is to and l2 having flat and V ways [3 and I4, reeliminate the necessity for continual adjustments spectively, formed thereonfor the support of a of steadyrests in the grinding of longand espetable or carriage l5 which, as shown in Figure l, cially flexible shafts. Another object of the inhas fastened. thereto the usual swivel table 16 vention is to permit the more accurate grinding having front and back ways ll, l8 by means of 10 of shafts and the like. Another object of the which, referring again to Figure 1', a headstock invention is to achieve extreme accuracy in the l9 and a tailstock 2|] are attached to the table setting of a steadyrest, and more especially in the 1 Sand therefore also the carriage l5. The headsetting of a plurality of steadyrests. Another stock has associated therewith a stand 2| for the object of the invention is to move a plurality of usual motor 22 having a pulley 23 driving a pull5 steadyrests synchronously. Another object of the ley 24 by means Of be t 2 The S a t 6 P invention is to increase the production of shafts which the pulley 2:? is mounted is connected by and the like which are ground. Another object gearing, not shown, in the head Hi to the usual of the invention is to increase production and work spindle, also not shown, which is accurately accuracy in the grinding of any object held bejournalled in the head l9 and receives headstock 20 tween centers and rotated. Another object of work center 2'! adapted to fit in one of the center the invention is to provide a complete grinding holes provided in the work piece, in this case a machine of increased accuracy and with autolong shaft 30. Connected to the work spindle is matic operation of one or more steadyrests. the usual face plate 3| with radial slot 32 in pointed out hereinafter. Tailstock 20 includes a hand wheel 35 for moving The invention accordingly consists in'the feathe usual tail center 36 horizontally, and suitable tures of construction, combinations of elements means, not shown, for clamping the tail center 36 and arrangements of parts, as will be exemplified in adjusted position. The apparatus'described is 0 in the structure to be hereinafter described, and not-in itself novel and constitutes a preferred emthe scope of the application of which will be inbodiment of means for holding and rotating the dicated in the following claims. shaft 30 between centers and also supporting it In the accompanying drawings in which is for reciprocatory movement relative to a grindshown one of various possible embodiments of the ing wheel 40. The latter is fastened to a wheel mechanical features of this invention, spindle 4| journalled in a wheel head 42 which is Figure l is a front elevation of a cylindrical mounted on slideways, not shown, normal to the grinding machine especially adapted for the slideways l3, [4, whereby the grinding wheel grinding of long shafts and having apparatus .acmay be caused to approach and recede from the cording to the invention including four steadyshaft 36. The machine preferably includes cross Figure 2 is an :enlarged transverse sectional type and is herein shown as including a shaft 45 view taken along the line 2--2 of Figurel through which may be the driving screw shaft and which the work table and one of the steadyrests; is operated by a ratchet 46 and pawl 41 together Figure 3 is a fragmentary view showing in with suitable micrometer control indicated at 50 a rest apparatus and in vertical section the slidepawl il of a type now well known and which is way for the upper steadyrest element; moved by the main reversing lever V 52 which Figure 4 is a plan view of the upper steadyrest controls the travel of the carriage l5. This mechelement; anism is not herein described in detail as any 50 Figure 5 is a fluid pressure diagram showing equivalent or substitute therefor may be pro- 50 the connections for operating the steadyrests and vided, and the cross feed may be hydraulic or a so o Operating the Work table carriage; mechanical or .of any other desired type, many Figure 6 is a perspective view of one of the base now being well known in the art. castings of a steadyrest unit together with the Referring toFigure 1 in connection with Figreciprocating the carriage I5. Relative reciprocation of the work piece and grinding wheel 40 is desired so far as certain features of the invenpiston 58 fastened thereto and located in a closed cylinder 59. PipesBIl and BI are connected to opposite ends of the cylinder 59 and lead from opposite sides of a main control valve casing 62. The bottom of the valve casing 62 is connected to a pump 63 while the top thereof is connected to an exhaust other suitable fluid from a tank 65 while thepipe 54 exhausts into the tank 65 by way of a throttle valve 66. A movable valve member 61 in the casing 62 is connected to the pivot shaft 68 of the reversing valve member 52. A suitable snapover or load and fire device, not shown, is provided to achieve a reversal in direction of travel of the carriage I5 as distinguished from a mere stop. The carriage I5, as shown in Figures 1 and 2, has a T slot 10 in which are' adjustably fastened striking dogs II, 12 to engage the reversing lever 52, thus to reverse the direction of travel of the carriage I5. The'foregoing brief description of a typical hydraulically actuated plain cylindrical grinding machine is given not by way of limitation but in order more readily to illustrate the preferred application of the invention.

Referring now to Figure 1, for the grinding of a long shaft 39 it has been customary to provide steadyrests. If a shaft were a. rigid body, steadyrests might be dispensed with but even a steel shaft of the relative dimensions shown is a flexible body when dealing in measurements of a thousandth of an inch and less. In fact, even very much shorter shafts may require one or more steady rests for precision grinding to within small limits owing to the inevitable spring which develops in the ing ground. 7 r

In the illustrative embodiment of the invention, I showfour steadyrest mechanisms 15 but more 'or less may be provided, depending upon the particular requirements. mechanisms may be cate of all the others.

Referring now to Figure 2, each steadyrest has a base casting 76 having an overhanging portion 71 which fits on the ways I! and may be clamped thereto by means of L head bolts gage dovetailed lip portion 19 of the table 'IS and. which bolts may be tightened by nuts 80 shown in Figures 2 and 3. Casting 'IB also has a foot Each of these steadyrest and preferably is a dupliportion 8| which rests on table I6. The casting I6 likewise includes parallel side portions82 between which extends a block;83 which is bored out to form a cylindrical bore 84 in which fits a piston 85 backed up by a spring 86, Piston 85 has a piston rod'8l extending through a cylinder head 88 which may fit in screw threaded engagement with the block 83;

Referring now to Figure 5, a pipe 9!! is connected to the pump 63 and is also connected to a horizontal pipe 9i which extends between stationary portions 92, 93 of the'machine base. The

pipe 9I does notmove, but slidably mounted on' it is an oversizedcylinder 94 having cylinder heads 96 bored to'receive the pipe 9| with a'fluid pipe 64. Pump 63 draws oil or shown, and it is is a'roller II8 which shaft or rod as it is bedescribedand fully shown for the 18 which enable member of the valve ,has two positions, shown respectively, the former tion by its individual control valve I02. cylinderbore 84 hasa bleed'hole I35 in the bottight sliding fit. Approximately in the center of the pipe 9I is an orifice 91 so that the cylinder 94 is filled with fluid under pressure at all times when the pump 63' is running. Considering now Figures 2 and 5, the cylinder 94 is attached to the under side of the carriage I5 and moves with it. A pipe 99 extends upwardly from the cylinder 94 to a long pipe I which is parallel to the cylinder 94 and in fluid connection with it. Connected to the pipe I 00 are a plurality of valve members I 9| individually controlled, as shown in Figures 1 and 2, by hand wheelsIOZ located on the front of the machine. On the upper part of each valve II'II is a fitting I03 which is connected to a flexible hose or pipe I04, there being four of these hoses in the illustrative embodiment of the invention as well as four of the valves IilI where four steady rest mechanisms 75 are provided. Each hose or flexible pipe I54 is connected to a nipple I05 located in the side of the block 83 and communicating with the inside of r the bore 84 thereof.

slideway casting nism which may III} for each steadyrest mechabe U shaped in cross section, as preferablycarefully ground to provide accurate, smooth slideway surfaces for a steadyrest element III which is shown out of the machine in plan view in Figure 4. This slideway 'member IIIl has flanges II2 through which extend suitable bolts I I3 by means of which it is fastened to the sides 82 of the casting 16 which it bridges. In the bottom'of the slideway III] is an opening I I 5 for an actuating lever II 6 pivoted on a shaft II! which extends between the side portionsBZ. On the upper end of the lever I I6 engages the head of the bolt II9 which projectsv intoa cutout portion I20 of thesteadyrest member II I. The bolt II9 may be suitably tightened in position by means of a nut IZI. V

I provide further a similar IIOiz in which. is located a steadyrest member II'Ia having a cut-out portion I290, into which projects a bolt II9a the head of which is engaged by a roller IIBz on the end of ,a lever IIGa pivoted on a. shaft 'I Ila. extending between the side portions 82, the slideway I I Elabein'g fastened to the base H3 in a manner similar to that slide member H6 and HM located in a III]. The other ends of the levers have ball portions I25 and 125m collar portion I26 formed onthe piston rod 81 for the piston 85.

Referring again to Figure 5, I provide a twoway valve I39 in the line 90 adapted in the position shown to'connect the two sections of the 'pipe 90 and in another positionv todisconnect the two sections of the pipe and connect the lefthand section thereof to a discharge pipe 'I3I which empties into the reservoir 65. The mov- V 7 I30 may be operated by a lever I32'which, as shown in Figure 1, may be located on the front of. the machine and which in full and dotted lines, representing the positionin which the two sections of the pipe 95 are connectedrtogether, and the latter representing the position in which the left-hand section of the 'pipe90 is connected to the exhaust pipefll 3 I.

All of the 'steadyrests maybe operated in unison by means of the control lever I 32. Any one of thesteadyrests, however, may be put out of ac- Each slideway member 1 I plurality of steadyrest mechanisms grip the work tom thereof through which any oil leaking past the piston 85 may discharge. This oil may coilect in a groove I35 running lengthwise of the and H511, respectively. Extending through these end plates are bolts I46 and I48a respectively on which are located springs I41 and him respectively. These springs insure the retraction of steadyrest elements III and la whenever the pistons 85 move upwardly in the cylindrical bores 84 of the blocks 83.

It will be observed from Figure 2 that the levers H6 and Ilfia are duplicates of each other. Furthermore, the axis of the cylindrical bore 84 and of the piston 85 intersects the axis of the work piece 38 and lies at an angle of 45 to the horizontal plane of the work piece axis and also 45 to the vertical plane of the work piece axis. Furthermore, the steadyrest element I II is mounted to move horizontally andthe steadyrest element I I la is mounted to move vertically. The steadyrest element I I I has two steadyrest shoes I58 and I5I which have plane surfaces for tangential contact with the work piece 38, the plane of the surface of the shoe I58 being parallel to the axis of the. piston 85 and inclined at 45 to'the horizontal. The contacting tangential plane of the shoe I5I is inclined 45 to the horizontal and is normal to the axis of the piston 85 and it follows that it is, therefore, normal or perpendicular to the contacting surface of the shoe I511. The steadyrest element I I la has but a single contacting shoe I52, the contacting surface of which is parallel to the axis of the piston 85 and also parallel to the surface of the shoe I58. While some of these relationships may be changed, it will be seen that this represents a balanced construction. Movement of a thousandth of an inch (or any other distance, for that matter) of the element III is accompanied by exactly equal movement of the element I I la.

As a result of this geometrical arrangement, the work piece 38 cannot be pushed out of its normal position coaxial with the centers 21, 35. of the grinding machine. Stating this in another way, the work piece 38;is held in a given or constant position as the steadyrests advance. Nevertheless, each steadyrest may exert any pressure on the work piece and may advance automatically in response to the hydraulic pressure of the system described. This hydraulic pressure represents aforce rather than a positive movement by reason of the provision of a pressure relief valve 55 in the pipe line 98, as shown in Figure 5.

It follows from the foregoing that, in case a piece, it will be truly centered thereby and the machine work centers 21 and 36 are relieved of the load of the work piece. In fact, once the work piece is centered by a plurality of steadyrests I5 as described, the center 36 may be backed off altogether so that it no longer centers the work piece (wherefor the other center 21 will no longer center the work piece), provided any suitable machine altogether.

means is provided to prevent endwise movement of the shaft 38. .In the operation of the machine, the centers 21v and 36 will preferably be kept in their usual positions relative to the work piece 38 or merely backed off a few thousandths of an inch in order to prevent endwise movement of the shaft 30. Nevertheless distinct advantages are achieved by providing a plurality of steadyrest mechanisms which automatically and accurately locate the work piece in so much as accuracy of location of the center holes in the work piece is no longer a matter of such importance. In other words, the work piece may be ground to concentricity with its previously turned cylindrical surface rather than to concentricity with the end center holes.

The automatic operation and centering of the steadyrest mechanisms renders it possible to grind a long shaft like the shaft 38 with no interruptions for adjustment of steadyrests and by a continuous grinding operation and with greater accuracy than has heretofore been possible. The uncertainties of operator control are'greatly reduced by this automatic centering mechanism described.

The relationship of the surfaces of the shoes I58, I5I and I52 is such as to make a three-sided box for the work piece, the grinding wheel 48 being atone of the other sides so that the work piece cannot move therefrom but is locked in position. Furthermore, as the shoes I58 and IE2 face each other, steadyrest elements cannot advance beyond the point where they are in tangency with the work piece as otherwise they would have to compress the shaft 38 which is virtually impossible, that is to any appreciable or significant extent with the pressures involved. The several shoes I58, I5I and I52 may be made of very hard material, for example they may be removable plates of pressed boron carbide or other similar substance or, on the other hand, they may be,

simply case hardened surfaces. It will be seen that the location of the various steadyrest mechanisms I5 may be varied on the machine within reasonable limits by reason of the flexibility of the pipes I84 and also one or more of the complete mechanisms may be readily removed from the Vital parts of the mechanisms including the slideways III] and steadyrest elements III may be readily removed and replaced if they lose their accuracy on account of wear. 7 If desired, I may provide removable cover plates I56 for the slideway members I I8 and similar cover plates, not shown, for the slideway mem hers I I8a to keep dirt out of the apparatus.

A feature of importance is that in all positions of the actuator 85, the steadyrest surfaces are equi-distant from the axis of the work piece. The axis of the work piece is the axis of the machine centers. However, the steadyrest surfaces themselves govern the position of the geometrical axis of the work piece by moving so that they are at all times equi-distant from a given line and cause this geometrical axis to be the axis of rotation, a condition distinctly to be desired in grinding. Measurements from the steadyrest surfaces to the axis of the work piece are made normal to the planes of the surfaces, so that the measuring lines are the radii of the work piece.

It happens to be the case in the illustrative embodiment of the invention that the elements III and IIIa move equal increments. This is because the'dihedral angle of the surface I58 to the horizontal plane of the work piece axis is the same as that of the dihedral angle of the plane piece axis, viz. in both cases 45. 'It is further because the dihedral angle of the plane of the rest 15! to the horizontalplane of the work piece axis is the same as that of the rest surface I52 to the vertical plane of the work piece axis, via. 45". i It will be remembered that the element Ill moves in the horizontal plane of the work piece axis and the element ill a moves in the vertical plane of the work piece axis. However, the plane of the rest surface I52 might be at a dihedral angle other than 45 to the vertical plane of the work piece axis, in which case the lengths of the levers H6 and Iifia wouldrbe changed to cause the elements H l and l I la to move at different increments. With the plane of approach of each steady rest element known and the angles of steadyrest elements areprevented from moving beyond that point Where they center the work piece in the desired position and this may be achieved using three steadyrest surfaces as shown in the same general relationship, or it may be otherwise achieved. I

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanyingdrawings is to be interpreted as illustrative and not in a limiting sense.

I claim:-- V

1. A steadyrest mechanism for grinding machines and'the like comprising a steadyrest element having two surfaces in the form of a V, a second steadyrest element having a single surface, an actuator for both elements, and connections whereby all three surfaces remain equi-dis- V tant from a given line in all positions of the actuator, measurements being made normal to said surfaces from the said line. 2. In a grinding machine, a plurality of steadyrests each having two movable steadyrest elements, fluid actuating pressure mechanism for ments of all of the steadyrests against a work piece, and positive connections between the fluid of the rest I52 to the vertical plane of the work pressure actuating mechanism, and the steadyrest elements positively to move each steadyrest element in definite relation to the other steadyrest element of such steadyrest.

, 3. A steadyrest mechanism comprising an actuator,ifluid pressure means formoving the actuator, two steadyrest elements, two slideways for mounting said steadyrest elements for movement located in such positions that the line of advance of the actuator bears the same angular relation to each of the slideways, and actuating connections between the steadyrest elements and the actuator of similar characteristics.

4. In a grinding machine, a movable table or carriage, a steadyrest on said carriage, fluid pressure actuating mechanism on said carriage for said steadyrest, a fluid pressure pump located in the stationary part of the machine, and fluid connections between the pump and the fluid pressure actuator including a sliding piston and cylinder connection. a

5. A steadyrest mechanism comprising two steadyrest elements'and having three steadyrest surfaces, there beingtwo surfaces on one steadyrest in the form of a V, the dihedral angle of such V being twice that of the angle between the steadyrest surface on the other steadyrest element and the line of its advance, and positive connections between said steadyrest elements to cause them to move by equal increments at all times.

6. In a grinding machine, a base, a carriage mounted for movement on said base, a plurality of fluid pressure actuators on said carriage, fluid pressure means constituting a source of fluid under pressure in said base, fluid pressure connections between said fluid pressure means and each of said actuators, a plurality of steady rest elements having steady restsurfaces for each actuator, and mechanical connections between 7 each fluid pressure actuator and its steady rest elements whereby all steady rest surfaces of said elements move in loci equidistant from a given line in all positions of such actuator.

7. In a grinding machine, a plurality of fluid 7 pressure actuators, fluid pressure means constituting a source of fluid under pressure, fluid pressure connections between said fluid pressure means and each of said actuators, a plurality of steady rest elements having steady rest surfaces for each actuator, and mechanical connections between each fluid pressure actuator and its steady rest elements whereby all steady rest surfaces of said elements move in loci equidistant froma given line in all positions of such actuator.

GEORGE CROMPTON, JR.

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