US1693723A - Grinding machine - Google Patents

Description

m vn LE, ame. HCE. cm@ nGd Mmm amp .wn R .m g .l r o Dec. 4, 1928 R. c. MITCHELL GRINDING MACHINE Original Filed Aug. 8.A 1921 8 Sheets-Sheet 2 ImfnT l Dec. 4, 1928.

R. C. MITCHELL GRINDING MACHINE Original Filed Aug. 8, 1921 8 Sheets-Sheet 5 Ng wd i 8 Sheets-Sheet 4 Dec. 4, 1928.

R. C. MITCHELL -c-MNDING MACHINE Original Filed Aug. 1921 Dec. 4, 1928. 1,693,723 R. C. MITCHELL Y GRINDING MACHINE original'med Aug. a. 1921 s sheets-sheet 5 [mieli-131;

Dec. 4, 192s.

R. C. MITCHELL GRINDING MACHINE Original Filed Aug. 8. 1921 8 Sheets-Sheet 6 rm @um Mam/M Dec. 4, 1928.

R. C. MITCHELL GRI NDI NG MACHINE Original Filed Aug. 8. 1921 8 Sheets-Sheet 7 8 Sheds-Sheet 8 Dec. 4, 1928.

R. c. MITCHELL v GRINDING MACHINE original Filed A'gQs. 1921 Patented lec. 4, 1928.

UNITED STATESl PATENT oFFICE. y

RAYMOND C. MITCHELL, OF SPRINGFIELD, OHIO, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO BARBER-COLMAN COMPANY, A. CORPORATION OF ILLINOIS.

GRINDING MACHINE.

applicati@ filed August a, 1921, seriai My invention -has Afor its general object to improve grinding machines--and in some of its features morev particular'l grinders of the sort shown in my prior atent No. 1,335,905, and my pending application Serial No. 403,999, filed August 16, l920-in matters affecting flexibility of operation; concerning ranges of speed of the work-rotating and table-traversin operations and cross-feeding without ta le reciprocation; accuracy' of setting for taper grinding; smoothness of operation and avoidance of shock and jars; eiiciency and convenience of' manual control; and economy and general improvement in mechanical construction making for minimum expense in manufacture. Y

Other and further objects of my invention will become apparent from the following description, taken in conjunction with the aecompanying drawings, wherein I have shown a preferred form of grinder embodying my invention. a

In the drawings, which in some respects are diagrammatic, departing from shopdrawing proportions whereV exaggeration seemed to clarify the construction, Fig. l is a .front elevation of a grinder embodying my invention; Fig. 2 is a side elevation thereof;

Fig. 3 is a plan detail viewed from line,

3-3 of Fig. 2; Fig. 4 is a detail in elevation viewed from line 4-4 of Fig. 2;.Fig, 5 Ais a front elevation with parts broken away tol show gearing and gear housing; Fig.- 6 is a section on line 6 6 of Fi 5;'Fig. 7'is a detailed'section on line 7 of Fig. 1; Fig. S is a plan detail of a portion of the tabledriving gearing, Fig. 9 is a schematically extended View 1n plan of portions of the table-driving and work-rotating gearings; Fig. 10 is a detailed section on line 10-10 of Fig. G; Fig. 11 is a detailof the hit-or-miss con-l trol devices on the front plate; Fig. 12 is an enlarged detail, With'parts broken away, of some of the control devices, viewed from'thc front of-the machine; Fig. 13 is a section on line 13-13 of Fig. 12; Fig. 14 is a front elevation with parts broken away of a modilied table-check and'Fig. 15 is a section on line 15-15 of Fig. 14.

0n t-he'main frame 20 the slide table 21 is mounted vfor longitudinal reciprocation drive 32 an 210.490.479. ,Renewed october 1, V

and upon the table the swing plate 22 is centrally pivoted in knownV fashion, head-stock 23 and foot-stock 24 being mounted on said. swing plate for longitudinal adjustment thereon in .known manner.` Grinding wheel. 25 Vis mounted in the carrier 26, capable of transverse or cross-eedingmotion at right angles to the line of table travel, and constructed and mounted for the usual adjustments.

I preferably provide for rtating the grinding wheel,^driving the work and reciprocating the table from the common power shaft 27, which itself may be driven in any suitable fashion as by a pulley rigging 28,

such shaft being preferably carried in brackets mounted on. the exterior of the frame casting 20. It may drive the grinding wheel spindle by belt`29 running over pulleys on the respective shafts and suitable idlers on the belt-trunk 30 that, to accommodate mo'vements of wheel carrier 26, is pivoted on the power shaft 27 and has adjustable link-connection at 31 to-the wheel carrier. The power shaft 27 ma be connected by a silent chain dy suitable sprockets with the jack; shaft 33, which-acts as a driver from which motion may be imparted to both the tablereciprocating mechanism' and tlie workdriving mechanism. Shaft 33 and as much as is possible of the gearing and shaftingl associated therewith, and the control devices, are all mounted in a sub-frame 34 that is structurally independent of main frame 20, so that assembly of most of the parts as to whichnice fitting is necessary, may be made Y .without providing shaft bearings in the Amain frame. The sub-frame 34 is preferably integral with the front plate 34 whichoovers a large orifice in the front of the main frame and is readily demount-able with all its mechanism. Preferably the sub-frame is made as a gear box closed at ends and sides to form a convenientpil'well.

As is schematically shown in Figs. 8 and 9, jack shaft 33 has its pinion 35 arranged to drive gear 36 on what I may term the main shaft 37 of the gear-nestfrom which power may be transmitted through one set of speedchanging gearing 38 to drive the table reciprocating mechanism and also, through another speed-changing transmission 39 to drive one of the is shifted longitudinally within the shaft.

the work-rotating mechanism (which, as in On reverse-gear shaft 54, that is supported my co-pending application No. 403,999, is wholly gear driven).

Table driving mechanism.

, shown provides a hollow shaft 41 paralleling 'l L `the main shaft 37' andhas loosely mounted upon itthe four gears 42.0f different sizes constantly meshing with the inversely vary- .ing gears/43 on the` main shaft. A rod 44 slides in the hollowY shaft, carrying a -yielding key 45 as shown in Fig. 10, that is springpressed laterally to protrude its blade` through a slot 46 in a hollow shaft, so that it may clutch into the suitable hub-slot of any gears 42, accordingly. as the rod For speed-changing control shaft 47 runs through the face plate 34"and carries handle 48 "co-acting with index dial 49, such ad \\`\44. Preferably spacing rings 52 between shaft aving thereon a gear 50 (Fig. 10) meshing with a cylindrical rack 51 on rod gears 42 present beveled edges to co-act with the beveled ends of plate\45 to insure passage of clutch plate from engagement with one gear 42 with another with a snap action. Said rings serve to prevent the possibility of; two being clutched to shaft 41 at the same time.

Thus, from constantly running shaft 37 shaft .,41 will be run practlcally constantly at #any one of., four selected speeds.'

Table reversing gearing is provided in conjunction with the change-speed gearing` preferably-:interposed between the four speed transmission and the high-and-low speed gearing. Reversing gear shaft( 54 (Figs. 8 and 9) parallels shaft 41 and is constantly driven therefrom, but in the effective geartrain I preferably provide a shock-absorbing or yielding connection for taking up strains that otherwise might be caused by changing the gear ratio in'thev four-speed transmission while the machine is running. 55

is a gear on shaft 41, constantly driven there,- bv and meshing with gear 56 on shaft 54. Gear 55, however, preferably has yielding connection with shaft 41. Fixed on shaft 41 is a three-armed spider 57, (Figs. 6 and 10), between the arms of which spoke-lugs 58 of gear 55 extend, springs 59 being interposed between the spider arms and spoke lugs, to give the tooth rim of the gear the capability to yield in a direction opposed to the driving rotation of the gear, fer` shock absorption purposes. In short, thejspider drives the rim through the spring.

that extends through front plate 34 and carries the manual and automatic lever means i Vfor effecting reversals of the direction of table traveled. A suitable flop-over device 65 of known construction insures that the clutch sleeveI will always stand in one or the other of its cluif-hing positions.

Gears oJ-60 constantly mesh with gear 66 on a cross-shaft 67.from which a'rackgear 68 may be driven throughv either the i high-speed or low-speed train, or allowed to idc. according tothe positionof the handle 69 on the front plate 34. As diagrammatically7 shown in 8,shaft 67 has loosely mounted thereon gear 70 that is in a reducing train leading to pinion 71 that meshes withy rack-gear 68,v and also carries a loosepinion 72 that is in an accelerating train leading to the pinion 71, these gear-elements 70'and 72 having confronting clutch members 7 3 for coaction with a clutch member 74 non-rotatably mounted on shaft 67 and slidable thereon from ancutral central'positio-n into positive clutch engagement with either of the gearelements 70 and 72. lA shifter lever -75 controllin to be cammed axially by a pin and slot arrangement 77, the slotted Sleeve of which is carried by control handle69.

One of the gears of the train driving rackgear 68 may mesh with pinion 78 directly on the shaft of a hand wheel 79 mounted on the front plate 34 for enabling'the table to be moved by hand power. The rackear 68, it will he understood, meshes direct y with a rack 86 carried by the table as shown in Fig. 5.

It will now lbe apparent that according to the selective positioning ofcontrol handle 69, table travel will be in the higher range. of Speed or the lower rangenof speed, or the table may be caused to remain stationary by throwing said handle into middle, neutral pofr clutch 74 is mounted on a slide rod 76 lll) sition; and in whichever range 0f speed-,the l s machine ma be 'caused to function table travel may e at any one of four selective speeds within that range accordingly" with the 'selective position of handle 48.

` Work rotating mechanism.

In my prior application, Serial No.403,999,

gear mechanism for impartingv rotation to the driving element 23 of the head-stock is bearings fixed in said table and said shaft 81A This shaft 81 being slidable through pinion upon reciprocation of the table. Connection is effected between shaft 81 and driving element 23 through a gearing in the swiveled housing 82 to drive a shaft 83 that may slide longitudinally through said housing-contained gearing, and that is equipped with a flexible joint -84 acting, in connection with the swivelling operation of the housing, to accommodate lateral displacement of the swing-table. In any position of the head-stock as to axial adjustment on theswing-plate, and lateral adjustment caused' by movement of the swingplate the drive from shaft 81 is effective.

is of square or other non-circular section and slides through a rotatable pinion 85 which is held against longitudinal movement by its mounting in the bracket 86 (Fig. 5) cast in or otherwise secured to the sub-frame. 84. This pinion may also be driven in high or low speed ranges, and with a speed-variation in either range, as diagrammatically shown in Fig. 9. To this end the change-speed transmission 39 has gears 42 and control mechanism worked from handle 48 identical in substance with the changespeed transmission described heretofore, the yieldingly mounted gear 55 thereof having a broad toothed surface making constant engagement with a gear 87 that has clutch-hub members-on both sides and that is slidable axially on shaft 88. In central position this gear turns the shaft 88 idly. At opposite ends of its sliding throw its clutch members engage clutch elements of gears 89, 89', loose on shaft 88 and respectively meshing with small and large gears 90-90 fixed on shaft 91, one of said gears meshing with the pinion 85, so that said pinion is driven in its high speed range when gear 87 is shifted to the left (Fig. 9) and low speed range when the gear'87 is shifted to the right. Shifter' arm 92 engages the sliding gear 87 and the slide rod 93 for said arm is worked from control handle 94 on the front plate, the short shaft 95 (Fig. 5) for said arm having a finger 96 engagin between collars 97 on said rod 93.

It wil now be apparent that by handle 94 the gearing for work-rotation may be thrown from neutral, inert condition into low-speed or high-speed ratio, and by operation of handle 48', any one of four selective speeds withinthe general range may be employed.

A11/tornati@ tablen--Reoz'procation and mtomatw cross-feeding.

In general the mechanism for automatically reversing the direction of table travel and for automatically effecting a cross-feed of the grinding wheel stand 26 are similar to those shown in my prior Patent No. 1585.905. Adjustable lugs 101 on the table may strike arm 102 Fig. 6) of a lever fast on the rock-shaft 64 which controls the table reversing clutch 62. A hand lever 103 provides for manual control in known fashion. An arm 104 of lever 102 (Figs. 11 and 12) co-acts with shiftable frame 105 carried on the cross-feed lerer 106 to depress the latter at each swing of arm 104 (when frame 105 is suitably positioned), cross-feed lever 106 operating through suitable ratchet' and pawl mechanism 107 (as more fully set forth in my said patent) to rotate, step by step, the cross-feed shaft 108. This shaft (Fig. 6) makes worm and worm wheel connection 109 with the vertical shaft 110 on which the wheel stand 26 centers, and the pinion 111 of such shaft meshes with rack 112 of the sliding head of said wheel stand.

It is very desirable, at times, to operate the cross-feed automatically when the table is not reciprocated, and of course under such circumstances cross-feed lever 106 will not be actuated by arm 104. I provide for the condition stated by arranging to drive the ratchet and pawl mechanism from a constantly rotated part of the gearing, at will, preferably by connections associated with the cross-feed lever 106 and so arranged that actuation of' said cross-feed lever from the conlstantly rotating part or from arm 104 are alternative, and cannot possibly be concurrent. For this purpose I bring the constantly rotating cross-shaft 67 of the reversing gear mechanism through the face-plate of the ma- -chine and equip it (Figs. 11 and 12) with an eccentric or cam 113 (although of course any constantly operated part, suitably positioned, might be utilized in lieu of shaft 67). The slide frame 105 I make adjustable along the lever 106 as by rock and pinion connection 105 to a point that takes it out of the range of motion of lever 104, and this frame I equip with a stud or block 114 that', with the frame at said extreme of movement, may serve to elevate into the path of operation of cam 113, a striker member 115 that takes the form of a bar pivoted co-axially with lever 106. As long as frame 105 is in any sition where it can be operated on by arm 104, block 114 is moved to the left of the position shown in Fig. 11 allowing the nose of striker member 115 to drop behind it, so removing the striker member from the field of operation of the cam 113. However, with the parts positioned as shown in Fig. 1`1, each rotation of shaft 67 will cause a depression of lever 106, and consequently a cross-feeding operation.

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To insure proper oilingy of the mechanism I provide an oil pump 117 (Fig. 6), mounted in proximity to the oil VWell of the gear casing, and preferably on the front plate 34. The spring pressed piston 118 is preferably worked by an eccentric 119 on a constantly running shaft of the gearing, and a piping connection 120 to the valved' intake side of the, pump chamber shown leads through a glass-fronted gauge chamber 121 i and to the lower p art of the oil'well. The

` front of the machine, the contracting adjustment of bolts 128 for the split cylinder caus ing it to grip with desired frictional resistance the solid roel 129. Striker blocks 130 mounted adjtistably on the sliding table (preferably in tandem with the lugs 101),

'may strike the rod 129 in suitably timed relation to the operation of lugs 101 on the table reversing mechanism, so that a portion of the momentum of thetable is taken up by the friction cliecledevice, and shocks to the ef'l'ective mechanism are greatly reduced and smoothness of operation most effectively enhanced. In Figs. Hand I have shown a modified construction in which spring pressed plungers 129', held in protruded position in respect to solid cylinder 1,27 by the action of springs.131, are employed, either spring resistance or frictional resistance being effective in'the checking operation.

In angular, or taper grinding, yit is often important to make very minute changes, laterally, in the positionlot the swing-plate, and I provide means for facilitating the obtaining of greatest nicety in making such adjustments, or securing for a second operation the identical position that was hadfor the first. As shown in Figs. 3 and 4, the end of lthe swing-tatie usually has a graduated scale 132 for aid in determining its adjustment, but

micrometric accuracy is difiicult to attain. I provide, therefore, on the slide-table and the swing-plate respectively, a micrometer andan adjustable stop soV related that the micrometer may be brought into operation at any point in the swing of the table, according to the setting of the movable stop, and

adjustments fromithat point determined With the greatest accuracy. Specifically 133 represents a frame'rigid on the slide table and having a cross-bar 134 along which a stop member 135 may be slid and secured in any adjusted position by screw 136. c The arm 135 of this stop-device projects into the path of the actuating stein 138 of a suitable rotary micrometer 139. The swing table may be roughly set to approximate position desired and then the stop-device 135 adjusted to press upon micrometer actuating it to show any selected reading. From this setting the operator can Work both ways with greatest nicety, and of course by noting the .micrometer reading at time of finishing one piece of Work, a duplicate can be reproduced. With greatest accuracy by maintaining the setting of the stop and Working until the micrometer reading is duplicated.

While I have herein described in detail a particular embodiment of my invention that is desirable in many details that I may claim for specific benefits, it will be understood that in the broader' aspects ot' my invention many changes and departures may be made from the specific construction shown Within the spirit of my invention and the scope of the appending claims.

I claim:

1. In a grinder. the combination of a slide table, a grinding -u'heelstand, cross-feed mechanism for the latter. automatic means for reciprocating the table, said table reciprocating means having operative connections to actuate the cross-feed mechanism. a constantly-moving part and means operatable from said constantly-moving part for actuating said cross-feed independently of table reciprocation.

2. ln a grinder, the combination of a slide-table, a grinding-Wheelstand, cross-feed mechanism for the latter, having a shiftable part. automatic means for reciprocating the table. said table reciprocating means having operative connections to actuate the crossfeed mechanism, a constantly-moving part and means operatahle from said constantly moving part for actuating said cross-feed independently of table-reciprocation, said shiftable parts being movable to render idle either operating mechanism alternativelv.

3. In a grinder, a slide-table, a swing-plate 'pivoted thereon, and a shiftable stop and a micrometer-gauge operatable by coaction With said stop, one associated With the table, ythe other with the plate.

4. In a grinder. the combination of a constantly-running shaft. a reciprocable slide table arranged to be reciprocated or stopped at will, a grinding wheel stand, crossfecd mechanism for thelatter including a vibratahle member (106) and dual means for actuating said member comprising an operating part moved hv the slide table. an operating part moved by the constantly running shaft and shiftable means for establishing operative connection between said member and either of said parts at will.

5. Structure as set forth in claim Aft. wherein the vibratahle arm carries tu'o elements for respective coaction with the tivo operating parts and one of these elements is arranged, but only When removed from coactive relation to its actua" ig part. te hold the other elc ment in coactive relation to the other actuating part.

6. Structure as set forth in claim 5, Wherein the respective operating parts are a lever (104) and a cam (113) and the tWo elements are a slide member (105) on the vibratable arm (106) and a striker member (115) for eoaetion with the cam, said slide member being arranged, vvhen moved ont of the path ot said lever (104) to latch the striker member in the path ot' the cani.

7. In a grinder, a slide-table, a swing plate pivoted thereon, a frame on the table having a stop thereon adjustable transversely of the table, and a micrometer gauge carried by the table having an actuating stem so disposed as to strike said stop when the table is swung.

8. In a grinder,- the combination With a frame, a driving shaft and a part to be driven; ot a tirst variable-speed selective transmission. a motion reverser anda second variable-speed selective transmission, connected together in series in said sequence, said first variable speed transmission being adapted to effect a continuons driving relation at one of a plurality of speeds and said second variable speed transmission being adapted to etl'eet a driving relation at either ot' two speeds or to interrupt the driving relation entirely.

i). In a grinder, the combination with a trame, a driving shaft and a part t0 be driven, ot' a gear train connecting said shaft and said part including, in tandem driving relation, two Variable-speed selective transmission gear mech anisms` one of said variable speed transu'iission mechanisms being adapted to eifel-t a continuons driving relation at any one of a plurality ot' speeds and the other variable speed transmission mechanism being adapted to effect a driving relation at either ot' t\vo speeds or to interrupt the driving relation entirely.

In testimony whereof I have hereunto subscribed m v naine this 12th day of July. 1921.

RAYMOND C. MITCHELL.

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