US1663760A - Grinding machine - Google Patents

Description

J. N. HEALD' ET AL GRINDING MACHINE March 27, 1928. 1,663,760

Filed Feb. 12. 1926 3 Sheets-Sheet 1 March 27, 1928. v 1,663,760 J. N. HEALD ET AL I GRINDING MACHINE Filed Feb. 12. 1926 3 Sheets-Sheet 2 March 27, 1928. 1,663,760

6 J. N. HEALD ET AL GRINDING MACHINE Filed Feb. 12. 1926 3 Shgets-Sheet 5 Patented Mar. 27, 1928.

UN T STATES PATENT OFFICE.

JAMES N. HEALD, or WORCESTER, ALBERT TURNER, or SHREWSBURY, AND enonen KIMMEL, or SPRINGFIELD, MASSACHUSETTS, ASSIGNORS To THE HEALD MA- CHINE COMPANY, or woRCESTEn, MASSACHUSETTS, A CORPORATION or MASSA- CHUSETTS.

GRINDING MACHINE.

Original application filed October 7, 1922, Serial No. 593,113. Divided and this application flied a February 12, 1926.

The present invention relates to grinding machines, and particularly to improvements in the construction and operation of the wheel feeding 'instrumentalities of a 'ma-' chine for grinding exterior cylindrical surfaces,although, obviously, not limited to'a machineof Such type. e

The present application is a division from our prior'application Serial 'No. 593,113, filed October 7 1922. e v

" The several features of the invention are described hereinafter and specifically pointed out in the appended claims, referencebe ing had to the accompanying drawings,}' I

tating 'work back'and forth in contact with,

wherein g I Fig. l is a view in front elevation of a grinding machine embodying the invention.

Fig. 2 is a similar View, on.a larger Scale, showing the wheel feeding mechanism removed from the frontof the machine. Fig. 3 is a top plan View of said mecha- IllSIll.

Fig. 4: is a transverse sectional view of said mechanism.

Figs. 5 and 6 are, respectively, planand. sectional views of a mechanism for varying the stroke of a feeding pawl; p

Figs. 7 and 8 are, respectively, front and sectional views on an enlarged scale, of an adjusting device carried by the hand wheel of the machine.

Fig. 9 is a plan view, partly in section, of a feed actuating mechanism adapted to operate independently of the travelof the table. Figs. 10 and 11 are front views of said feed actuating mechansim, showing it, 118;: Spectively, in operative and inoperative position.

Like reference characters refer to like parts in the difierent figures. i

The invention is shown in connection with a grinding machine for operation on extev rior cylindrical surfaces, having a base. 1 whichprovides longitudinalways 2 for the.

reciprocatory movement of awork. carrying table 3; the work tobe ground issupported in the well known manner between centers 4' and 5 provided, respectively, by a head stock 6 and.a tail stock 7, both carried by table 3 and adjustable thereon to. accommodate pieces of work of different lengths.

Serial No. 87,798. I I

ters 1 and 5;' this rotation, inconjunction' "with the vsimultaneous reciprocation'of the work afforded by movement of table 3, sub

jects"alliportions'of'its surface to the action suitably' journalled in a head or slide 9, the

latter, Jb'yfitsinov'ementin suitable trans-f verse ways "9, Fig; 4, procu'ring the feed of thc' gr nding'wheel toward and from the The movement oftable 3, to carry the rothe grinding v'vheelS, may be effected by any desired means, such as a fluid pressure controlling and'reversing mechanism of the 'type,jror instance, disclosed in the co endl-Ieald and Turn'er, Serial No. 574,940, filed July 14, 1922. The construction and oper-' ation of this mechanism. for reciprocating of a rotating grinding wheel which is the work forms nopart of the present invention, it beingsufiicient to note. that a reversingvalve' for the motive. fluid, not Shown,1s operableby a lever 10, the latter having a pin-and Slot' connectiomlikewise not shown, with a rocking member 11, whos e upperend projects into the path of a pair of adjustable, dogs, 12 and; 13 .carried by, the. table, 3. These stopsor dogs 12, andl3 env gage the member 11 alternately whereby ,to reverse the direction of, travel of the table,.3 at each engagement; their. longitudinal adjustment determines,,the,throw,, or length of i table travel, .forany givenoperation.

The: cross feed movement of wheel .head 9 is obtained bythe-usual mainv screw Shaft 14, A Fig.4, which cooperateswith a nut 14', at-; tached to the wheel head, to cause movement of the latter toward and fromthe work.. In i one of its aspects, theinyention contemplates the feed-of the. grinding wheel toward the work in response to the reciprocations of the .1 table 3, thestops' or dogs 12 and13 ,belng utilized for successive; actuationsfof the wheel feeding mechanism to procure agpre determined feed of the grinding wheel each traversing movement of the work.

To this end a member 15, pivoted to the machine frame at 16, carries a roller 17 which is disposed in the path of pro'ections 18 and 19 provided, respectively, by t e dogs 12 and 13. A link connects member 15 to a rocker arm 21, the latter adapted to swing on the axis provided by a shaft 22, on WhlC is also journalled a ratchet wheel 23. A spring 24, attached to arm 21, acts yieldingly todraw said arm about its axis in aclockwise direction, Fig. 2, and thus holds the roller 17 of member 15 in position to be engaged by the travelling projections 18 and 19. These projections, at each engagement with roller 17, act to depress the free end of member 15 and thus, through link 20, to rolar. displacement of ratchet wheel 23 is communicated to the feed-screw, to efl'ect a lateral shifting of the wheel head 9; the feedscrew, however, has only a very small angular movement, in comparison to the angular movement of ratchet wheel 23, because of the gearing 26, 27,the arrangement being such as to require, for instance, five completerevolutions of the ratchet wheel for one revolution of the feed screw.

At eachengagement of the roller 17 with the travelling projections 18 and 19, the member 15 is always depressed to the same level, due to the fact that no further downward movement of the roller 17 can be produced, by further movement in either direction of the table 3, after said roller reaches the horizontal alined surfaces 18' and 19 of said projections. In this way, the operative stroke of arm 21 is made to terminate always at the same point, and thus the feed of ratchet wheel 23 by pawl 25 is not subjectto any such accidental variation as would be apt to result from the table 3 traveling at a high speed, or from the tendency of said table, by reason of its inertia, to drift beyond the point selected for its reversal. In-

other words, regardless of variations in the movements of the table, the movements of the roller 17 produced by said tablenever exceed a predetermined amount, and the excess movements of the ,table are without efiect on said roller.

In conjunction with the above described means for insuring the stoppage of pawl 25 always at-the same point on its operative stroke, the invention provides means for adjusting the travel of said awl on its re turn or inoperative stroke, w iereby the op erator is enabled to fix with exactitude the number of ratchet teeth on wheel 23 that will be picked up by the pawl, for any given feedin operation. To this end, the return or cloc wise movement of arm 21, under the influence of spring 24, is subject to limitation by means of an irregular rotatable cam 28 disposed in. the path of a projection 29 of link 20, Fig. 5. The cam 28 is journalled on a stationary stud 30, as shown in Fig. 6, and is provided with suitable means for turning it by hand, such as a knob 31. A spring'pressed pin 32, cooperating with suitable shallow depressions 33 in the bottom of cam 28, insures the correct disposal of said cam in the various positions of adjustment to which it may be turned, for the purpose of opposing its high, low, or intermediate portions, as desired, in the path of projection 29. The handle 31 is preferably so inscribed as to indicate the adjustment of the cam 28', with reference to an index mark on the stud 30, as shown in Fig. 5,-thus enabling the operator to fix in advance the number of ratchet teeth on wheel 23 tobe picked up by pawl 25 at each stroke of arm 21, to give a fine, medium or coarse feed of the grinding wheel, as desired. It should be noted that the cam 28, although irregular,

has a smooth peripheral surface, without jogs or breaks, by reason of which it can be turned in either direction to adjust the amount of feed by simply turning the handle or knob 31 ;the parts for which it acts as a stop do not have to be touched by the operator.

The feeding mechanism provides the usual hand wheel 34, which is also loosely journalled on shaft 22, the same as the ratchet wheel 23. Said hand wheel 34 has secured thereto a radially disposed bracket 35, Figs. 7 and 8, which provides a journal portion 36 for the reception of a rotatable member 37, the latter adapted to be turned by a knob 38, Fig. 7. The connection of knob 38 to member 37, for turning the latter, is by means of a spindle 39, securecb to said handle and keyed to said member; the spindle 39 provides :1. normally projecting toothed portion 40, adapted to mesh with the teeth of ratchet wheel 23. A spring pressed pin 41-, adapted to enter a series of notches 42 provided by member 37, operates as a friction lock to prevent accidental displacement of member 37 and spindle 39 and thus serves to insure rotation in unisonof hand wheel 34 and ratchet wheel 23, except when the handle38 is seized and turned on its own axis, or when said handle is pulled back to retract the pinion teeth 40 from their engagement with the teeth of wheel 23; this last named retraction is accomplished by the compression of a spring 43, which normally holds the pinion teeth neea co and ratchet teeth in engagement, as shown in Fig. 8, to lock the hand wheel and ratchet wheel together.

The hand wheel 34 carries on its periphery an inwardly projecting plate or shield 44, Figs. 2 and 8; this shield 44 is referably, though not necessarily, carried y the bracket of said hand wheel and, being disposed in overlying relation to the ratchet teethof wheel 23 is adapted, when carried into the zone of action of pawl 25, to prevent operative engagement of said pawl with said ratchet teeth. In other words, the shield 44 may be set or fixed to intercept the pawl, following a predetermined automatic feed of the grindingwheel by said pawl, whereby to discontinue said feed as soon as the Work has been ground down to a predetermined diameter.

With the ratchet wheel 23 in the exact position that it assumes for a given desired diameter, the hand wheel 34 is adjusted, relative to the ratchet wheel 23, to bring the shield 44 into position for just intercepting pawl 25 this is done by retractin knob 38 so as. to allow free movement of the and wheel Without disturbing the exact setting of the ratchet wheel. Thereupon, the knob 38 is released, allowing the hand wheel and ratchet wheel to be locked together again by the meshing of pinion teeth'40 with the teeth .of the ratchet wheel. With the shield 44 thus adjusted in fixed relation to a predetermined toot-hon the ratchet wheel 23, the grinding wheel 8 can be fed backward to allow the introduction of an unground piece of work; with this setting of the shield 44 maintained, subsequent automatic feeding of the grinding Wheel by the action of pawl 25 is always interrupted at the proper time, to

prevent the work from being ground below the predetermined desired diameter. It is to be noted in this connection that the stepby-step rotation of knob 38, past the successive notches 42, provides for a delicate adjustment of the shield-44 in bringing it exactly to. its desired pawl-intercepting osition. This delicate adjustment. is usefu not alone in obtaining the exact setting of shield 44, but can also 'be availed of to readjust said shield from time to time, to compensatefor the gradual wearing down of the surface of grinding wheel 8.

In another of its aspects, the inventionflinvolves mechanical means for procuring the feed of the grinding wheel on straight incuts, i. e., when there is no traversing of the wheel by the work and hence no engagement of member 15 to actuate pawl 25. Under these conditions, the drive for the feed is from a suitably journalled rotating shaft 58, Figs. 3, 9, 16 and 11, said shaft being drivenfin any smtable manner as by. means of-Ia sprocket wheel 59 thereon which may be connected by a sprocket chain, not shown,

'one of which (the with a suitable driving sprocket on the main shaft of the machine, not shown. On one end said shaft 58 carries an eccentric pin 60, the latter projecting into the hole or opening 61 of a member 62,.and carrying a contact roll 63. The member 62 is pivoted at 64 to the arm 21, and on one position of said member, as illustrated in Fig. 11, a spring pressed pin 65, engageable in a notch provided by extension 66 of. arm 21, maintains said member 62 under the influence'of the rotating eccentric contact roll 63, whereby to produce the oscillation of lever 21 and the consequent automatic feed of the grinding wheel, through pawl 25 and ratchet wheel 23. It will be understood that the limitin 6, here ofore described in connection with the table feed of the grinding wheel, is also operable, under these conditions, to produce a fine, coarse, or medium feed of the grinding Wheel. When the table feed is inoperative, or when it is desired to feed by hand mechanism shown in Figs. 5 and i instead of mechanically, the pin 65 is reconnection with this type of mechanical feed, which is useful' more especially in grinding short pieces that do not .require traverse of the wheel, the cessation of feed, when the work is ound to size, is accomplished for each piece by a proper setting beforehand of shield 44, in recisely the same manner as described for t e table-feed mechanism, to throw out the pawl 25.

We claim:

1. In a grinding machine, wheel feeding mechanism comprising a ratchet-wheel and pawl, the latter being movable on its operative stroke always to the same point, anirregular but peripherally smooth cam without jogs or breaks in its surface for limiting the rentrn or inoperative stroke of said pawl, and indicating means associated with said cam for procuring its. adjustment for the desired number of ratchet-wheel teeth to be passed over by said pawl'on its inoperative stroke, the cam being turnable in either direction of rotation to the desired adjustment, by reason of its smooth surface, without-the necessity of otherwise moving the parts for which 'it acts as a stop.

2. In a grinding machine, wheel feedin mechanism comprising a ratchet-wheel an' pawl, an irregular but peripherally smooth rotatable cam without jogs or breaks in its surface for limiting the return or inoperative stroke of said pawl, a spring pressed pin and a cooperating series of depressions, 1pm or the series) is 10-. cated in said rotata le cam to accurately determine the various positions thereof, and indicating means associated with said cam for procuring its adjustment for the desired number of ratchet-wheel teeth to be passed over by said pawl on its inoperative stroke, the cam being turnable in either direction of rotation to the desired adjustment, by reason of its smooth surface, without the necessity of otherwise moving the parts for which it acts as a stop.

3. 'In a "grinding machine, a rotating shaft, a grinding wheel feeding mechanism comprising a ratchet-wheel and pawl, a

a collar pivotally connected to said member,

a pin on said collarewhereby it may be con:

nected to said member in two different positions, an eccentric on said shaft located in said collar, whereby the ratchet and pawl mechanism may be operated from, said 1'0- tating shaft or not, depending on-the position of said collar on said member.'

JAMES N. HEALD. ALBERT TURNER. GEORGE C. KIMMEL.

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