US2923518A

US2923518A - Hydraulic duplicating mechanism for machine tools and the like

Info

Publication number: US2923518A
Authority: US
Inventors: Goodrich Max
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-08-27
Filing date: 1953-08-27
Publication date: 1960-02-02
Anticipated expiration: 1977-02-02

Description

Feb. 2, 1960 DRI CH 2,923,518

M. GOO HYDRAULIC DUPLICATING MECHANISM FOR MACHINE TOOLS AND THE LIKE Filed Aug. 27. 1953 3 Sheets-Sheet 1 INVENTOR 1- My aaoax c/ BY w ZVh/Zw M /CMWM ATTORNEY Feb. 2, 1960 M. GOODRICH HYDRAULIC DUP LICATING MECHANISM FOR MACHINE TOOLS AND THE LIKE Filed Aug. 27, 1953 3 Sheets-Sheet 2 0 0 a 2 W u/ w 4 4 w v, A 3 x 7 0 0 47 a T. 5 2 6 I 6% /r fl c K r m u I II Il fl In H 0 M a 1 006 8241M a 2/ mnm 7 a Z7 4/ 7 2 8 p w a U d St tes Pa m 0,

HYDRAULIC DUPLICATING MECHANISM FOR MACHINE TOOLS AND THE LIKE Max Goodrich, Holt, Mich.

Application August 27, 1953, Serial No. 382,535

Claims. (CL251-3) The present invention relates to improvements in hydraulic duplicators attachable to such machine tools as vertical mills, boring mills, lathes, planers, shapers, and

the like for controlling the movement of the tool.

Devices of the type to which the present invention pertains are well known commercially and a great many noncommercial proposals pertaining to such devices ap-,

extremely fine work and which permits the practical manufacture of an attachment of high precision performance.

Thus, an object of the invention is to provide an improved hydraulic tracer unit so designed that the sensitivity of the tracer finger to all changes in contour of the master template, or the like, is transferred to the valve mechanism which controls the manipulating fluid in such a manner that the sensitivity of the tracer finger thus transferred is undiminished, unretarded and in direct proportion. 7

Another object is to provide novel structural arrangement in devices of the type described for obviating the tendency toward chatter in the performance of extremely fine duplication.

2 Fig. 4 is an exploded perspective view of the sectional structure of the control valve,

Fig. 5 is a detail of the connection between the valve and stem structure, t p

Fig. 6 is a view similar to Fig. S taken through'the ports of the dampening structure, V

Fig. 7 is atop view of Fig. 3, and v I Fig. 8 is a detail of the structure for maintaining the valve chamber full of oil.. I i I,

As shown in Figs. 1 and 2, the duplicator attachment 10 is carried upon suitable cross slide structure 12 attached to the vertically movable spindle structure of the milling machine 14 so as to follow the movement, of the tool 16. Adjustment of the attachment 10 in a horizontal plane is providedto align the tracer finger 18 with the tool 16 as well as withthe template 20 mounted on a bracket 22 to move with the table 24 upon which the work 26 to be machined is carried. V

The carriage structure 28 of the attachment 10 comprises a lower split bushing portion 30 in which the tracer stem housing 32 is vertically. slidable. A suitable at tachment bolt 34 having a handle 36 is provided'for clamping the split sleeve30 upon the housing 32 following vertical adjustment, As shown, the housing 32 has an extremely threaded surface 38 to receive the adjustment nut 40 in position for rotation between the upper surface 42 of the sleeve 30 and the lower surface44 of the thrust plate 46 attached at 48 to the carrier 28. A surface of the nut-40 may. have graduations marked thereon to aid in the vertical adjustmentof the housing 32 upon manual rotation of the adjustment nut 40.

Referring to Fig. 3, the tracer finger 18 is heldin the stem 52 by a clamp screw 54. With the finger 18 .out of contact with the template 20 the stem 52 is vertically supported by the stem holder 56 which takes the form of an externally threaded bushing screwed into Another object of the invention is to provide a tracer the free movement of the A further object is' to provide a conveniently located-"' regulator for actuatingthe control valve. wherebyjthe operator may bring the tool into contact with the, work with extreme care. These and other objects and advantages of the present invention residing in the combination, construction and arrangement of the component parts will appear from the following specification and the appended claims.

In the drawings,

Fig. 1 is a perspective view of a vertical milling mav chine equipped with my improved duplicator attachment,

'Fig. 2 is a perspective view of the tracer and control valve unit shown in its mounting structure,

Fig. 3 is a vertical cross-sectional view of the trader and control valve unit shown in Fig. 2,

the internally threaded counterbored lower end 58 of the stem housing 32. To remove all s1ack between this threaded connection,. a spring 60 is inserted between the upper end of the stem holder 56 and the shoulder 62; the spring 60 being sufiiciently strong as to prevent any side movement between the threaded connection when there is side pressure on the tracer finger 18.

The stem 52 has a concentric slightlyenlarged cylindrical portion 64 which is provided with an extremely close sliding fit within a narrow annular surface constituting what is-characterized herein as an annular fulcrum 66; in practice the clearance between the sliding parts constituting the sliding fit being in the orderrof V 'of the cylindrical portion 64 is attached to engage to support the stem 52; the seat portion 68 being disposed 'at to a radial line between a point of contact between the edge 70 and the seat portion 68 and the point of intersection of the longitudinal axis of the cylindrical portion 64 with a medial plane through the annular 'fulcrum 66. 60

The axial extent of that portion of the annular fulcrum 66which forms the .0002" sliding fit with the cylindrical portion 64 is in the order of 1A3". With this narrow bearing and with .0002" clearance, side movement inall directions may take place at, the lower, end of the tracer finger 18 to the order of A with the tracer finger of usual length, namely, in the order of 3" to 5" below the fulcrum 66. With the seat portion 68 located and constructed as above described, only slight movementof the edge 70 will take place on the seat 68 and such movement will not produce any appreciable upward camrning movement to the stem 52. Clearance is provided at 72 f between the lower end and the stern 52tto accommoj'nut118 holds the socket 117 in position. V 'Iheadjustable connection between the upper threaded end'pf the rod 116 andthe valve spool 120,'best shown Fig. ,5, comprises an internallythreaded' sleeve 122 date the side movementfofthe finger 18 inall directions,

"The ster n 52 is extended a substantial distance above the fulcrum 66, preferably: a distance approximating the distance to: the lower end, of the finger18 to provide the up er end 74 and the annular ball, seat 76 withapproxi- ,mately the sameamount ofside movement as may take place at the lower end ofthe tracer finger 18..

. -To transfer both axial and lateral movement of the stem 52 to' the sectional valve shown in Fig. 3, a ball 78 rests upon the seat 76' and reacts against a similar annular. seat 80 defined in the" externally threaded pin abutment member82 which is-also the i nner race of the ball gazette, a e

bearing. structure84; The outer race for the bearing 84 :takes the for'ni pf a sleeve 86pressed intoa counter- ,hore at the upper end of the stern housing 32. Retainng rings 88 hold the bearings 84 positioned. Below the nner race portion of the member 82 is a threaded port1on 89-to;wliich a tubular guide 90 for the inner race is threaded. At the lower end of the guide 90 is a bushing 92' having a sliding fit on the stem 52 at a point adjacent the annular fulcrum 66s0 any deflection of the bushing 92 upon sidemovement of the finger 18 will be extremely small andiunappreciable at the upper end in the plane of the bearing 84. Thus, it will become apparehtthat the ,member 82 is supported inthe stem 32 only for vertical movement to be imparteclthereto by theball78 by both axial and' -l'ateral movement. of the seat 76. 1

To attach the stem 32to the main valve. body 94, the

f u'pper" end of the.stem 32 is threaded to the plate 96 which iii-turn is piloted upon the valve end plate 198' and, at-

tached to the body 10 by screws 100. Hardened hushmgs 102 and 104 are pressed into a central opening 106 in the plate 98 and shaped to provide an, oil chamber 108.

Pin,110.'rides on the top of the member 82 with a closelsliding fit which permits very little oil to pass by yetthe pin 110 is freely slidable in the bushings 102 and .104; At its upper end, the pin 110 abuts a metallic washer 112 and acts, through a resilient cushion or pad. 114, preferably of synthetic rubber, upon the push 'rod 116.. The lower threaded end of the rod, 116 receives a socket 117 which holds. thecushion 114. between the the annular port areas plishedby removing the threaded cap 142. A plunger 44 against whichithe spring 138abuts at itsupper eiid has a manual push rod 146' which may be depressed to build up the compression upon the spring 138 should the valve spool 120 become stuck in its raised position.

The four-way valve construction for selectively directing the hydraulic fiuidto opposite ends of the cylinder 148 attached to thespindle structure functions in a well known manner. Movable valve spool 120 is provided with lands 150 which are machined with "great accuracy as to width, spacing; and diameter. To provide corresponding' accuracy of construction in the fixed ported structureof the valve, the sectional construction of Fig. 4 is stacked withinthemain through bore 152 and comprises an upper section 154, an intermediate section 156 and a lower section 158 Between these sections are spacer port rings 160 and 162 which are milled to provide radial ports with the surface 168 between the teeth 166 being inclined, This arrangement provides the spacer rings 160 and 162 with, maximumstren gth. Also, the 1 rings 160 .and 162 may be ground on opposite sides to control their thickness with great accuracy as well as the thickness of 170 between the surface ref-the

sections

154, 156 and 158 spaced .by the

rings

160 and 162 and regulated by thelands 150.

It will be understoodth t.the end surface of each

section

154, 156 and 158 are conveniently groundparallel and the overall length readilyfheld to extreme accuracy. Thus, the structure of Fig. 4 when stacked within the bore 152 will have its over, all length accurately held and the port areas 170 will beaccurately located with respect lower endof the rod 116 and the washer 112. The lock having an annular flange 124. To expand the upper end er the rod ,116 to lock it to the sleeve .122, the rod .116 is first drilled to onedepth by a small drill, then to a lesser depth with alarger drill. The larger holeis then tapped and the end of the rod 116'is slotted at 116' at right angles beyond the depth of the smallfdrill. Thus,

screw 126 may be rotated and advanced to engage the shoulder 116" formed between the holes of" difierent diameter. to expand the externally threaded slotted. end; of the rod 116' into locking engagement with the internal threads of the sleeve 122. At the upper end the valve spool 120 is counterbored at 128'to receivethe flange 124 of the-sleeve 112'. An annular groove" 1-30' in'the .shoulder 174.

to each other as well as with respect to ,the lands150. Acap172 bolted to the body 94 locatesthe fixed valve structure of Fig. 4 between Thecap 142 is threadedinto the cap '172 gasket at 174 and'an O-ring 176 ducted by an appropriate passageway in body 94 to the ports. of section 156 and. depending on the direction of movement1oflandsL150 will either flow into chamber .187 or 189 throughqthe port areas.170. Chambers '187 and 189 are. in communication with cylinder connections 188 and. 190, respectively, by means of passageways formed in body .94, not shown, and the ports of sec fvvhen the rod,116' is held. against. rotation by a suitable .wrenchiengaging the slots, the pointed. end'of' the set tions .154 and 158, will provide communication with the exhaust passageway of connection 186 whereby communieatien" of connection188 withthe pressure fluid opens 190 l to the'exhaustand vice versa to move the cylinders 148 u in the desired directioncounterbore 128 receives a two-piece locking ring 132.

Iiloted upon the sleeve 122. is aslidable collar. 134 having a radial flange portion '136'to provide a seat for. the spring 138 and a thin cylindrical lower end portion 140 of slightly lesser diameter than the lockjring 132 tohold i the same in its groove 130 to lock the sleeve 122 to the spool 120.

' trolling valve chatter" p when the widths of the'lands 150 areonly in the order a of .00 widerthan the .port area 170. as is done when extremely fine duplication is desired. ,Any tendency for f the valves' eerl'zam vibratepor chatter is overcome by Referring-WOLFE. 6;.the structure 'is shown for conwhiclif has a tendency to, develop maintaining the'valve chamber full ofoil and metering From .this it should appear that thespring 13 8 acts downwardly on the valve spool120 indirectly through the collar 134 and flange 124 while the rod 116 acts upwardly" 'onthe valve spool 120 through the flange'124 I and the lock ring 132. By adjusting the sleeve 122 along: the rod 116, the position offthe valve spool 120" relative 't'oits fixed ports may be adjusted." Thismaybeaccomneedle, valve 182. )p g mentbffthevalv'e spoolfis controlled 'byrthe' flow l shown in Fig. 61 if depen the valve chamber,

Fig. 3 is showri inplan view with the oil pressure inlet connectionat' 184,, the'oilfpressure exhaust connection at "186' and the oi the oil between opposite. ends otthe valve chamber between 'paiss'ages 178;"and' .18 0 regulated by the adjustable In this'umanner, the rate of moveof oil past the needle 'valve182.

, Itwill be apparent that the ,oil' check arrangement dentupon maintaining of oil in Referring to Fig. 7, thecap 172 of pressure; connections leading to opposite ends of the cylinder 148'beingindicated at 188'and 190.

1 64 defined. between radial teeth 166 the bottom plate 98 and the be sealed withinthe chamber] in The intake 6 To-conduct oil from the connection 184 a horizontal passage 192 opens into the lower endof the vertical threaded hole 194. An inclined passage 196 extends from adjacent the upper end of the hole 194 into the cen- 'tral opening 198' in the cap 172 which defines the upper portion of the valve chamber. 4 V r A screw 200 having a gasket 202 beneath its head is threaded into the hole 194 to regulate the flow of oil in the

passages

192 and 196; the oil under pressure seeping along the spiral clearance between the threads of the hole 194 and the threads of the screw 200, the clearance being regulated by the diameter of the threads of the screw 200.

The oil in the valve chamber which enters through the passage 196 is exhausted through the passage 204 into the chamber 206 and out the passage 208 into the exhaust connection 186. The chamber 206 is in the form of a hole threaded at its upper end to receive the screw 210 which seals the upper end of the chamber 206 and acts as an abutment for the spring 212 which holds the ball valve 214 to its seat. The pressure of the spring 42 controls the oil pressure within the valve chamber.

As more clearly shown in Figs. 2 and 3 a collar 216 embraces the lower end 58 of the stem holder'56 and is removably aflixed thereto in any suitable manner as, for example, by means of a pin 218. A manual knob 220 is provided for rotating the collar 216 and the stem holder 56 as a unit relative to the stem housing 32. Such rotation will result in the stem holder 56 being raised or lowered depending upon the direction of rotation due to its threaded connection at 222 with the lower end 58 and the housing 32. To limit the amount of rotation of the collar 216 to a partial revolution, an armate recess 224 is machined from the end thread of the housing 32 to provide shoulders 226 at the ends of the recess 224 with which a pin 228 carried upon the collar 216 will engage.

It will be appreciated that when the collar 216 is rotated in one direction the seat portion 68 acts upon the edge 70 to lift the stem 52 and move the valve spool 120 into its up position to raise the tool 16. When the operator Wishes to lower the tool 16 into engagement with the work 23 rotation of the collar 216 in the opposite direction will enable the operator to cautiously approach the work with the tool. Thus, the collar 216 provides a conveniently located control means for raising and lowering the tool 16 relative to the work. When the tracer finger 18 is to engage and follow the template 20, the collar 216 will be rotated to remove the seat 68 from the edge 70 thus transferring the support of the tracer stem to the tracer finger 18.

I claim:

1. In a hydraulic duplicator attachment for machine tools and the like, a fluid control valve, means for actuating said valve comprising a tracer finger, an elongated axially movable stem carrying said finger, fixed port struc ture regulated by said valve, a housing for said stem, a seat carried byrsaid housing at its lower end and having a central aperture through which said stem extends, an annular radially extending shoulder on said stem and engageable with said seat to support said stem, said stem housing having a reduced annular portion directly adjacent and above said seat defining a narrow closely fitted annular fulcrum for said stem and defining the pivotal plane of said stem, said stem having clearance with said housing above and below said plane for limited pivotal and axial action in all directions about said fulcrum.

2. In a hydraulic duplicator attachment for machine tools and the like, a fluid control valve, means for actuating said valve comprisinga tracer finger, an elongated stern carrying said finger, a tubular housing for said stem, a narrow annular fulcrum for said stem located at the lower end of said housing which consists of a reduced annular portion with which said stem has a closely fitted axially slidable association, and a connection between '6 the upper end of said stem and said valve'for transferring axial movement to said valve upon pivotal and axial movement of said stem.

3. In a hydraulic duplicator attachment for machine tools and the like as defined in claim 2 wherein said con; nection comprises a ball disposed between a pair of annular seats.

4. In a hydraulic duplicator attachment for machine tools and the like as defined in claim 2 wherein said stem has an annular shoulder and said housing is provided With an annular seat directly adjacent said annular fulcrum upon which said shoulder is adapted to be supported.

5. In a hydraulic duplicator attachment for machine tools and the like as defined in claim 2 wherein said stemhas an annular shoulder and said housing is provided with an annular seat directly adjacent said annular fulcrum upon which said shoulder is adapted to be supported, that portion of said housing carrying said seat and fulcrum bsling axially adjustable to raise said stem and actuate said v ve.

6. In a hydraulic duplicator attachment for machine tools and the like, a lapped valve mechanism having opposite end portions for selectively controlling the flow of hydraulic 'fluid to opposite ends of an actuating cylinder upon minute movement of said valve structure, spring means for urging said valve structure in one direction, tracer mechanism for urging said valve structure in the opposite direction, and a hydraulic dampener for said valve structure to prevent chatter thereof comprising a closed hydraulic fluid circuit extending between the opposite ends of said valve structure with the latter functioning as a piston in said circuit and an adjustable restriction in said circuit for regulating the flow of hydraulic fluid therein.

7. In a hydraulic duplicator attachment for machine tools and the like, a lapped valve structure having opposite end portions for the regulation of the flow of fluid to opposite ends of a cylinder upon minute movement of said valve structure, spring means for urging said valve structure in one direction, tracer mechanismVfor urging said valve in an opposite direction, and aclosed hydraulic circuit for obviating chatter of said valve structure under the influence of said tracer mechanism connecting the opposite ends of the cylinder in which said valve functions as a piston and an adjustable restriction in said closed circuit for regulating the transfer of hydraulic fluid from one portion to the other thereof.

8. .In a hydraulic duplicator attachment for machine tools, movable valve structure for regulating the direction of fluid flow to and from a hydraulic actuator, a

tracer finger, a tracer stem structure connected between said finger and said valve structure for imparting the movement of said finger to said valve structure, an externally threaded stem housing concentrically encompassing said stem structure, mounting structure for said stem housing including a sleeve in which said stem housing is vertically slidable, and an internally threaded adjustment ring rotatably supported by said sleeve with which said stem housing is threaded for vertical adjustment of said stem housing in said sleeve upon rotation of said ring.

9. In a hydraulic duplicator attachment for machine tools, valve structure comprising a movable valve spool, a sectional sleeve valve in which said spool is reciprocated, said sleeve valve being in the form of a pair of ported sections separated by a relatively thin spacer section, said ported sections having end walls spaced by said spacer portion, said spacer portion being in the form of a ring having radial teeth on the inner circumference thereof with portions between said teeth being inclined to' ment of said tracer finger to said spool va'1v,e,1and

man mu:

Itracer fingen-andsaid.spo0l,va1ve for impartingih eforce transmitting; cushion memberimpossd betwcenpqaidV stem and saidspool valve. l H A 5 l 1 1 11 .L

. ,51 aL I Qm- V, UNITED STAT? PATENTS, -.2; 2 ;8.4 1 .52 531,719! R ll fi-g-l-qrr Ap 6 191 0 2;6'18,2 4 R m 1-, -1 1252