US3034265A - Grinding machine rapid advance motor - Google Patents

Description

May 15,' 1962 J. DECKER 3,034,265

GRINDING MACHINE RAPID ADVANCE MOTOR Filed Sept. 7, 1960 6 Sheets-Sheet l INVENTOR. JACOBDECKER TTORNEYS May 15, 1962 J. DECKER GRINDING MACHINE RAPID ADVANCE MOTOR 6 Sheets-Sheet 2 Filed Sept. '7, 1960 INVENTOR. J/ICOB DECKER flTTOR/VEYS May 15, 1962 J. DECKER 3,034,265

GRINDING MACHINE RAPID ADVANCE MOTOR Filed Sept. 7, 1960 6 Sheets-Sheet 5 8 INVENTOR. 84 4 JA 00B DECKER R P v /24 yWI 21 M L J HTTORNEYS May 15, 1962 J. DECKER GRINDING MACHINE RAPID ADVANCE MOTOR 6 Sheets-Sheet 4 Filed Sept. 7, 1960 lZZ INVENTOR. JACOB DECKER yzytk flTTOfPN EYS May 15, 1962 Filed Sept. '7, 1960 J. DECKER GRINDING MACHINE RAPID ADVANCE MOTOR 6 Sheets-Sheet 6 CIR BYPASS FEED RATE 60/? VAL V155 H AZ 5 Z/9Z/9 CR FAST-SLOW/NFEED /LS MOTOR RHTE 6 2272292 99 c'o/vnqcrs FOR as 0/? ca/vmcrs FOR 2L5 F i .5B

INVENTOR. JACOB DECKER United States Patent f 3 034,265 GRINDING MACHINE RAND ADVANCE MOTOR Jacob Decker, Cincinnati, Ohio, assignor to The Cincinnati Milling Machine Company, Cincinnati, Ohio, a corporation of Ohio Filed Sept. 7, 1969, Ser. No. 54,440 1 Claim. (Cl. 51-165) ance after a grinding operation is completed. The feed movement takes place during the cutting portion of the grind cycle. A hydraulic piston'and cylinder is generally used in the plain and angular slide types of hydraulic grinders equipped for automatic cycle to provide axial translation of a crossfeed screw during the rapid movement. The crossfeed screw is then rotated by a feed motor to provide the feed movement. Although this is a practical and successful mechanism for these machines, it has not proved to be adaptable to the universal type grinder which is distinguished in one respect from the plain and angular slide machines by its wheelhead which is mounted on a swivel base to allow for angular adjustment of the cutting surface of the wheel relative to the axis of a workpiece. It is desirable to provide an automatic cycle for the universal grinder, however, even though serious limitations are imposed on the infeed mechanism of such an automatic universal grinder. The mechanisms must not interfere with the swivel mounting of the wheelhead and should not substantially add to the shop space required for operation of the machine. Therefore, conventional use of the crossfeed screw is inconvenient since it limits the swivel movement of the wheelhead. The hydraulic piston and cylinder adds --bulky structure to the rear of the machine and becomes impractical as a means for furnishing rapid translation of the feed mechanism.

It is therefore an object of this invention to furnish an infeed mechanism which does not interfere with the swivel mounting of a universal grinder wheelhead.

It is a further object to supply an infeed mechanism for an automatic cycle machine which can be contained within the base of the machine with no resulting increase in bulk of the machine which would cause additional shop space requirements. I

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof, and it it to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claim, without depart ing from or exceeding the spirit of the invention.

When constructed in accordance with the preferred form of this invention, a grinder infeed mechanism utilizes a rack and pinion drive, the rack being fixed to the wheelhead and the pinion being fixed on a rotatable drive shaft supported in the machine base on which the wheelhead is received. This rack and pinion arrangement provides both the rapid movement of the wheelhead toward and away from the workpiece and also the slower feed movement. The pinion is connected to the feed motor by a driving train which includes, between the feed motor and the pinion, a rapid advance motor so that the pinion can be driven either by operation of the rapid advance motor or by operation of the feed motor through the rapid advance motor. The drive shaft rotates around a fixed axis and by placing the axis about which the wheelhead is made to swivel on this same axis, the engagement between the drive shaft and the wheelhead can be maintained for any angular position of the wheelhead. The rapid rotation of the drive shaft producing rapid movement of the wheelhead is provided by a paddle type motor. The body of the motor is carried on the drive shaft. The drive shaft extends into the motor body where a paddle extending from the shaft is received for limited rotary movement. The motor body is easily contained within the base of the machine where the drive shaft is supported. When the paddle is rotated to produce rapid movement, this motor body is in a fixed position relative to the base, but during feed movement it rotates with the drive' shaft. The feed power is furnished by a separate feed motor during feed but which is utilized as a brake mechanism to restrain rotationof the body of the paddle motor when that motor is operated.

A clear understanding of the construction and operation of this invention may be obtained from the fol-lowing detailed description and the attached drawings wheretions broken away for clarity.

FIG. 2 is a sectional view of the infeed mechanism of the grinder in FIG. 1 on line 2-2.

FIG. 3 is a section of FIG, 2 on line 33.

FIG. 4A and FIG. 4B show the hydraulic feed circuit of the machine.

FIG. 5A and FIG. 5B show the electrical control cirbase 13 of the machine and is pivotally adjustable thereon. The exposed portion of FIG. 1 shows the location of the feed mechanism which is contained in the base 18 by the motor enclosure portion 20 of the base. The cross feed shaft 22 extends through the motor enclosure portion to the front of the machine where it is geared to a handwheel assembly 106 (FIG. 4B) and the hydraulic feed motor 118, located at the front of the machine below the table.

The section view in FIG. 2 shows the structural details of the paddle motor. The wheelhead 10 which carries a grinding wheel 24 and guard 26, is located on the ways 14- in the intermediate member 12. The intermediate member is located on the top of base 18 and is pivotally adjustable on the swivel surface 28. Y A rack 30 is fixed to the wheelhead .10 and extends parallel to the ways 14. The rack is engaged by split pinion 32. The lower part 32a of the split pinion is fixed to a drive shaft 34 and the upper part 3% is fixed to a torsion bar 36. The torsion bar is received through the drive shaft 34 and has secured thereto a clamp 38 held against rotation relative to drive shaft 34 by pins (not shown). The torsion bar and drive shaft 3-4 have a relative twist which is preserved by the split pinion being engaged with the rack on one end and the clamp 38 on the other end. This twist eliminates backlash between the rack and pinion. The dfive shaft is supported in the motor enclosure portion 20 of the base 18 in tapered annular bearings 40 and 42. The housing or body of the paddlemotor 43 is comprised of a top member 44, a middle member 46, and a lower member 48 on which a worm wheel form has been machined. The body is received on the shaft 34 and held Patented May 15, 1962 in place by nuts 59 and 52. The drive shaft 34 is rotat- ,able in limited amount relative to the body in annular bearings 54 and'56. These bearings 54 and 56 also hold the shaft and body rigidly concentric relative to each other. The worm wheel form of the lower portion 48 of the motor body is engagedby a worm 58 which is fixed on the'cr'ossfeed shaft 22.

FIG. 3. shows a cross section of the paddle motor received on the drive shaft 34. The motor body encompasses a cavity 62 which'is concentric with the shaft 34 and has a radial wall member fid'fixe'd'therein. This wall, which is connectedto memberdti limits the cavity 62 man angular arcrof less than 360 degrees around the shaft. Extending from the shaft is the paddle segment 65 which is fixed to theshaft and received in the cavity The paddle segment may be swung within the limits of the cavity 52 from oneside of the wall 64 to the other to produce the limited rotary movement ofthe shaft 3'4 relative-to the body of themotor 43; Positive stops 68 are "fixed in each side of the wall 64 to engage stop pa ds' .70 of the paddle segment 66 as that segmentis caused to move frorrron'e end of the arcuatecavity to the other end.

to fluid passage 76 (FIG. 2). That line opens through port 72 (FIG. 3) tothe c'avity in the paddle motoron one side of the paddle segment 66 which swings to rotate shaft '34. Atthe same time, fluid line 90 which connects to fluid passage 73 (FIG. 2-) opening through port 74 (FIG. 3) to thecavity on the other side of the paddle I segment and line 92 (PEG. 4A) are connected through motion mechanism in the driving train between the feed motor 118 and the wheelhead 10 to produce a fixed amount of rapid movement of the wheelhead. When the peddlesegment completes its swing, the rapid advance movement is stopped, and the pressure switch 3P3 (FIG.

, 4A) is operated. Pressure continues to be supplied to the Fluid under pressure is selectively supplied 'to the cavity:

through ports 72 and 74 in th'e shaft 34, which are terminal cndsof fluid lines 76 and '78 (FIG; 2') and the ports 64:: (the port including an adjustable ball restriction in the wall member 64). Lines 76 and 78 are'selectively connectable to a source of fluid under pressure and to {drain to supply fluid under pressure to the cavity d2 between the paddle segment 66 and one side of the wall member 6-4- and to remove fluid from the cavity between the paddle segment and the other side of the wall member. This causes the paddle-segment to swing within the cavity from engagement with one side of the wall member 64 to'e ngagementwiththe other side. In swinging,

the paddle segment rotates the drive shaft 34 to which it is fixed.

FIG. 4A and FIG. 4B show the hydraulic circuit of and relief valve RV are assumed to bei-in operation-as are all of'the electrical elements of the machine. To

paddle motor through line .92 however. I This holds the paddle segment against the wall in the rnotor housing and the paddle motor becomes a rigid part of the driving train. 7 V

When pressure switch SP8 is operated solenoid ZSOL is energized and the'plunger of the pilot valve 126 is caused toshift left and pressure from line 84 is applied the grinding machine described. The hydraulic pump P T initiate the cyc1e,.a lever-8ilf(FlG. 4B) of the cycle. 7

start valve EZ/is pulled forward and the full pressure line' 84 is connected to a hydraulic line 86 connected to-the pressure'switch 5P8. Conversely, pushing lever 80in the opposite direction connects pressure line 84 to'line 85.

This will operate pressure switch 4P8 and terminate automatic cycling. Upon the operation of the pressure switch 5P8, solenoid ISOL (FIG. 4A) is energized to shift the plunger of valve 94- down; Fluid lines 34 and 88 are connected and lines 90 and 92 are connected in the Wheelhead control valve 94. Line 92 connects through valve 168 to the drain line 124. Pressureis connected through the selector valve .96 (FIG. 4A) from line 88 to line 98 nected through valve 96 (FIG. 4A) to line 9% which is now connected to the main return line 92. The fluid is Z and the shifter bracket 100 (FIG. 4B). Line 174 is conallowed to escape from the right side of the shifter 10% (1 16.413). The shifter .moves to the right and meshes gear 192 with gear 194 in the handwheel mechanism 1%. Gear 104 is mounted to rotate gear 108 which in turn is meshed with gear lltl on the end of the crossfeed shaft Worm gear 116., The worm gear 116 is driven by'the hydraulic feed motor 1-18 through gears 12%: and 12,2. As long as thehydraulic feed motor .is maintained in a static condition the paddle motor body of the paddle motor 43 (FIG. '2) will not be allowed to turn since the described gear traiirand hydraulic feed motor are all mechanically connected and furnish a braking mechanism to oppose rotation of the paddle motor body. When switch SP8 is closed, fluid-under pressure is also supplied from line 84 through'valve 94 to line 88 which connects r to line 128; I The plunger of the motor cut-off valve 130 shifts right when pressure is in line 1 28. Line 132 is connected .to line 134. At the same time, the plunger of. the pilot valve 136 has shifted left since solenoid 4SOL is also energized when pressure switch 3P8 is operated and pressure from. line 84 is connected to line 138 to shift a the plunger of the fast rate cut-off valve 144} to the right. I

At this time lines -88 and 144 are connected in the pressure reducing valve 142. Fluid under pressure, moves through the pressure reducing valve 142 to line1 144. From there,-the reduced pressure fluid goes throughthe check valve -1{i6; line 134, valve 139, line 132 to the motor' reversing valve 148. where it connects to line 150;

Line 159'connects with the hydraulic feed motor "118 the crossfeed shaft 22'and the worm. 58 (FIG. 2) to effect rotation of the paddle motor *body 48 and the drive shaft 34 to produce a feed movement of the wheelhead on the ways toward the table 16 (FIG. 1). Fluid is exhausted from the feed motor 1 1% (FIG. 4B) by way of fluid line 1 52 which connects with line 154 in the motor reversing valve 148 (FIG. 4A). Line 154 carries the fluid to the fast rate cut-olf valve the plunger of which has shifted to the right to connect lines 15 and 156. A The return fluid from. the feed-motor passes through the fast grind rate valve 158 to the returnline IMdraining tQ the fluid reservoir. The setting of the fast grind rate valve then controls the Wheelhead feed rate for the first period of the grinding cycle. 5 V

After apredetermined amount of feed movement, so-

amount of feed at this slower rate, the feed is stopped completely by a positive stop (not shown) engaged by the handwheel mechanism 106. After a predetermined time, solenoid ISOL is deenergized and the plunger of the wheelhead control valve 94 is caused to shift back to the position shown. Lines 84 and 90 are connected and lines 88and 92 are connected. This reverses thefiuid pressure differential in the paddle motor 43 and thepaddle segment swings rapidly back to its initial position.

The rotation of the drive shaft 34 (FIG. 2) is reversed and the wheelhead rapidly retracts from the workpiece, the amount of retraction being equal but opposite to the rapid advance movement. The feed motor 118 (FIG. 4B) and the gear train connecting to the paddle motor body again act as a brake to restrain the movement of the paddle motor body relative to the machine base. At

-the end of the rapid retraction, the fluid pressure diiferential in the paddle motor holds the motor body and drive shaft in a relatively fixed relationship.

When the plunger of the wheelhead control valve Q4 changes its position to connect lines 88 and 92, and lines 84 and 9!}, pressure through line 90, the crossfeed selector valve 96, and line 174 attempts to move the shifter bracket 100 (FIG. 4B) to the left, tending to engage gears 164 and 110 to reverse rotation of the crossfeed shaft 22. At the same time, the pressure in line 90 is causing the plunger in the reversing valve 148 (FIG. 4A) to move upward to the position shown at a rate controlled by the restriction 166. During the shift, lines 132 and 152. and lines 150 and 154 are momentarily connected. This provides a momentary reversal of the feed motor 118 allowing the backlash between the gears 164 and 110- to,be adjusted to allow these gears to mesh. Lines 132 and 150 and lines 154 and 152 are reconnected then and the fluid motor 118 again runs in the original direction. Solenoid SSOL is energized at the same time that the rapid retraction takes place and the plunger of valve 171 shifts to the left to connect pressure line 84 to line 170. When pressure is in line 170, the plunger of valve 168 shifts left. Line 154 is connected to drain line 124. The feed motor 118 runs at a rapid rate now to restore the wheelhead to its starting position. Since at the start of the retraction stroke, the feed motor and rapid retraction motor may be both operating at the same time for a brief period, the worm wheel 114 (FIG. 4B) driven by the feed motor 118 is furnished with an over-running clutch (not shown) to prevent the rapid retraction movement of the paddle motor from turning the hydraulic feed motor and causing interference with the normal motor action when the rapid retraction takes place. 7

The hydraulic feed motor runs until the wheelhead has reached its initial position relative to the work table and solenoids ZSOL and SSOL are deenergized. The plunger of the motor cut-off valve is caused to move left and to block line 134 from line' 132. The plunger of the rate valve by-pass valve 168 moves to the right to block line 154 from the return line 124 and the hydraulic system is returned to its initial static condition ready for another cycle.

r The electrical control circuit for the wheelhead mechanism described is shown in FIGS. 5A and 5B. (Horizontal reference locations on FIGS. 5A and 53 will be indicated as a number prefixed with the letter Z and parenthesized herein.) To start the machine, the master start switch SW1 (FIG. 5A,. Z20) is momentarily closed to connect relay 3M (Z20) across the control voltage lines LL1 and LL2 through closed contacts of the stop switch SW2 and contacts of switch SW1. Relay 3M is energized and picks up. The hydraulic pump motor MTRS (Z6) is then energized through contacts of the relay 3M which connect the motor MTR3 to power supply lines L1, L2, L3. When the hydraulic pressure produced by the pump P (FIG. 4A) which is driven by motor MTR3 reaches a preset level, the pressure switch 1P8 is operated and its contacts (FIG. 5A, Z23) are closed. Switch SW1 may be momentarily closed again to pick up the grinding wheel motor start relay 1M (Z23). When relay 1M is picked up, the grinding wheel motor MTR1 (Z3) is connected to power lines L1, L2, L3 through contacts of the relay 1M.

After the machine electrical circuits are energized and before the grinding cycle is commenced, a dog 130' (FIG. 4B) on the gearing of the internal portion106a of the handwheel mechanism 196 operates the limit switch 1LS.

(The handwheel mechanism is geared to the feed motor such that the internal portion 106a rotates relative to the linkages 132, 184 as the. feed motor 118 is operated. Also, with selector valve 96 (FIG. 4A) in the position shown, line 172 is not pressurized and the plunger 186 is forced down by the lever. 188 and spring 190 to allow limit SWitChlLS to be operated by the handwheel mechanism 196a; During setup, line 172 is connected to pressure linedd-through selector valve 96 to elevate plunger 1'86 and hold the limit switches 1LS and 2L5 in their lower positionas shown against an elevating bias force. in this condition limit switch 1LS operated and limit switch 2LS unoperated which puts the control circuit in a condi tion suitable for manual operation.) Relay GCR (FIG. SB, Z38) is picked up at the start of the cycle through contacts of the limit switch 1L3. The cycle start switch SW3 (FIG. 5B, Z25) may be closed now to start the grinding machine through a cycle of operation. When switch SW3 is momentarily closed, relay 10R (Z25) is momentarily picked up through contacts of the pressure switch 4P8, cycle stop switch SW4 and switch SW3. (By pulling the lever an (FIG. 4B) forward, contacts of pressure switch SPS (FIG. 5B, Z26) are momentarily closed and will start the cycle as previously described by furnishing a by-pass circuit aroundthe switch SW3.) When relay ICR is up, the relays 2CR1 (Z27) and 2CR2 (Z28) are picked up through contacts of relays lCR, 6CR, switch 4P8 and the switch SW4. Relays 2CR1 and ZCRZ latch up through contacts of relay 2CR1 and the tarry timer 2TR (normally closed, time opened, instantaneous closed). When relay 2CR1 is up, solenoid 1SOL (Z16) is energized and shifts the wheel-head control valve 94 (FIG. 4A) plunger to start the rapid infeed movement of the wheelhead. Therelay 2CR2 being up causes the motor control relay 5M to be picked up, When the relay 5M is up, the headstock motor MTRS (Z9) is connected to lines L1, L2, L3 through contacts of relay 5M. Motor MTRS rotates the workpiece during the grinding operation. Relay 2CR2 being up also causes relay 50R (Z37) to be picked up through contacts of relays 2CR2 and 7CR (normally closed) and solenoid 4SOL (Z19) is energized through contacts of relay SCR. This shifts the pilot valve 136 (FIG. 4A) left and a fluid return path is opened through the fast feed rate valve 158 from the feed motor 118 (FIG. 48).

At the end of rapid advance, pressure switch SPS is operated and relay SCR (FIG. 5B, Z29) is picked up through contacts of relays 7CR (normally closed) and 2CR2 and the pressure switch 3P8. Solenoid ZSOL (FIG. 5A., Z17) is energized through contacts of relay 3CR. The pilot valve 126 (FIG. 4A) shifts left and causes the motor cut-off valve to allow fluid to flow through the hydraulic feed motor 118 (FIG. 4B). The feeding movement of the wheelhead begins. As the feeding movement begins, the handwheel mechanism 106 begins to rotate and theldog 18!) moves to a position to allow limit switch 1L8 to be released. The contacts of limit switch 1L8 (FIG. 53, Z38) are opened and relay 6CR (Z38) is dropped. After apredetermined amount of feed movement, the limit switch 2L8 (FIG. 4B) is op erated as the roller 192 on the internal portion 196a of the handwheel mechanism 196 has been rotated to a position allowing the lever 184 to move up. The control relay 7CR (FIG. 5B, Z39) is picked up through contacts of limit switch ZLS. When relay 7CR picks up, relay SGR (Z37) is dropped and solenoid 4SOL (Z19) is deenergized. The fast feed rate cut-off valve (FIG. 4A) sends the return fluid from the feed motor 118 through the slow feedrate valve 162. The spark out timer 2TR (FIG. 5B,, Z34) is started when relay 7CR is pickedup and the contacts thereof in the timer circuit are closed. During the time that the timer 2TR is operating, the handwheel mechanism engages the positive stop (not shown) and further feed movement of the wheelhead is prevented. Shortly thereafter, the timer The infeed motor ,is not stopped when relay 21313-2 is dropped since a latch'circiiitexists through the-nort mally closed contacts of reIaysZCRZ md fiCR andfco'ntacts of relay 30R which holds relay ;;3 CR ener gized after the wheelheadh'as; started retractionniove- 'At this time, after relays ,Z CRl and 2CR2 merit. have dropped, the'plunger of the reversing valve 148 '(FIG. 4A) is shifting and momentarily eifects reversal of the feed motor 118 (FIG. 4B) to allow the gears 164 and 11% tomesh as the'shiiter 104) moves to the left; RelaydCR (FIG. 53, Z32) also picks up through contacts of relays 3CR and ZCR i (normally closed) when relay ZCRI is dropped. When relay 4CR V is picked up, solenoid 3SGL (FIG. 5A, Z18) is energized through contacts of relay 4CR and the feed motor exhaust fluid'is returned to the reservoir through the byepass valve 168 (FIG. 4A). Thefeed motor 118 now drives the handw'he'el 106 and the worm gear '58 in the opposite directionto retnrnthe handwh'eel and wheelhead to their starting positions; During the return to the starting position, the internal portion 1960 of the handwheel release limit switch ZLS. When the wheelhead and handwhe'el have returned to their starting positions, limit switch 1L5 is operated by the internal portion 196a of the handwheel mechanism 1%. The contacts of limit switch 1L5 (FIG. S B, Z38) are closed and relay 6CR is picked up. When relay @CR is picked up, relay 3CR (Z2?) is dropped and solenoid ZSOL (Z17) and relay 4CR (Z32) are deenergiz'ed. 1 When relay 4CR is deenergized, solenoid 3SOL (Z18) is'deenergi'zed. The electrical system and hydraulic system'are' now in their starting condition and the cycle maybe begun again.

What is claimed is: H In a'g'rinding'machine having a source of fluid under pressure, a base, a wheelhead, and an intermediate member mounted on the base and gpivotally adjustable thereon around an axis, said intermediate member having a way to siidably receive. the wheelhead, a mechanism to effect rapid'and feed movements of said wheelhead on said way comprising in combination, a rack fixed on said Wheelhead and parallel to said Way, a drive shaft supported in the base for rotation on said axis, said drive shaft having a radial paddle segment extending therefrom and a bore therethrough," a torsion shaft, received in said bore and extending thereth r'ough concentric with said axis, a split pinion engaged with said rack having one portion fixed on said torsion shaft and another portion fixed on 7 said drive shaft, means to maintain a predetermined relative twist between said drive shaft and torsion shaft operable to eliminate backlash between said rack and split pinion, a motor 'body received on said drive shaft and rotatable relative thereto having a worm wheel portion and a cavity therein concentric with said shaft, said cavity receiving said paddle segment and having a radial wall defining extreme angular positions of the paddle 7 segment therein, saidcavity havinga port on each side of said wall, a shaft journaled in the base having a worm engaged with said worm wheel portion operable to control rotation of'said motor body relative to said base,

means selectively to connect said source of fluid'nnder pressnr'e'to one ofsaid cavity ports to swing said paddle segment to one of said extreme angular positions and rotate said drive shaft for rapid movement of said-Wheelhead on said Way, a feed motor connected to said Worm shaft to rotate said worm for rotation of said motor body and drive shaft to effect a feed movement of said wheelhead on said 'Way after said paddle segment engages said wall, the paddle segment being held against said wall by said fluid under pressure at said one port, and means alternately to connect said other cavity port to pressure and to reverse said worm to retract the wheelh'ead.

References Cited in the file 0t this patent UNITED STATES PATENTS Germany 1 May 28, 1937

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