US2398556A - Surface treating machine - Google Patents

Description

April 1946- w. s. PEARSON 2,398,556

SURFACE TREATING MACHINE Fild Feb. 28, 1944 4 Shets-Sheet 1 5. Tauszw.

April 16,- 1946. s; PEARSON 5 SURFACE TREATING MACHINE I Filed Feb. 28, 1944 4 Sheets-sheaf, 2

William 6.7earson.

AP I 1946- v w. S. PEARSON 2,398,556

SURFACE TREATING MACHINE Filed Feb. 28, 1944 4 SheetsShee-t 3 S ZI ili z'am SJean'son.

April 16, 1946. w. s. PEARSON SURFACE TREATING MACHINE Filed Feb. 28, 1944 4 Sheets-Sheet '4 i l i' lf m 5.1%amm Patented Apr. 16, 1946 SURFACE TREATING MACHINE William S. Pearson, Severnalark, Md., assignor to Peerco, Inc., Park Ridge, 111., a corporation of Illinois Application February 28, 1944, Serial No. 524,272

14 Claims.

This invention is directed to an improved machine for treating the surfaces of objects such as by grinding, polishing or buffing the same.

It is an important object of the present invention to provide a machine of the above character which is well adapted for so treating objects which have a multiplicity of surfaces, this machine being arranged so that a plurality of such surfaces may be treated simultaneously.

Itis another object of the present invention to provide an improved surface treating. machine havin a plurality of operating elements for simultaneously treating surfaces of an article requiring different length work strokes.

It is still another object of the present invention to provide an improved surface treating machine having a plurality of operating elements for treating a multiplicity of surfaces requiring different length work strokes and having means for interchanging, between the elements, the different strokes so that each element is worn evenly and thus the life thereof is extended.

It is another object of the present invention to provide such a machine having a plurality of working elements together with operating means including limit members which delimit the length of the working stroke of each of the tools, the tools being so mounted that they can be quickly manipulated with respect to the delimiting members so that each tool will assume the working stroke previously passed through by another. In other words, there is'provided herein an arrange-v ment of limiting means whereby the stroke length of the tools can be interchanged for successive operations.

By way of exemplification of my invention, the machine shown herein is adapted for surface treating a forked member such as a cable end having a pair of parallelly extending, spaced legs, each leg being provided with a boss through which connection receiving apertures are drilled. In manufacturing such a device it is necessary to smooth down the sides of the bosses after the drilling operation, this smoothing operation being performed heretofore on a milling machine. Preferably the opposite sides of each of the. prongs are treated together so that working pressures are in opposite directions. The treatment of the outer surface of one of the prongs requires a relatively long stroke of the tool or disk, while the treatment of the inner surface can be accomplished only by a relatively short stroke of the tool. In other words, the grinding area on the'inner and outer surfaces of each of the bosses may be of different dimension. Thus it will be seen that when the surface treating disks operate on one of the bosses, one of the disks will pass through a longer stroke and the other through a shorter stroke. On the other hand, when the device is moved relative to the device so that the disks can operate on the other boss, the disk which formerly operated through a longer stroke on the outer side of-the first boss must now operate through a shorter stroke on the inner side of the second boss. Likewise the disk which formerly passed through a shorter stroke on the inside of thefirst boss must now pass through a longer strokeon the outside of the second boss. l

Accordingly, it is another important object of the present invention to provide apparatus of the above character with a plurality of surface treating implements, each of which is adapted to be operated through a working stroke of different length than that through which the other passes, therealso being provided means for varying the stroke length of each implement so that each may be madeto assume the stroke of the other during a successive operation.

It is another important object of the present invention to'provide an apparatus having the above characteristics and yet in which there is provided for each of the implements a direct driving connection to a source of power.

It is a further object of the invention to pro vide a novel delimiting arrangement whereby the working stroke of each of the disks is changed with each shaft in the device being worked upon.

Still another object of the'present invention is to provide an improved supporting structure for the movable'implements whereby a minimum of force is required to urge the same through a working stroke" and whereby the efforts of the operator are thus available almost entirely for accomplishing the movement of the implements through their working stroke against the work piece. l

In accordance with the general features'of the present invention there is provided therein an improved grinding, polishin or buffing machine having a stationary base and a work holding assembly, said assembly being mounted in laterally shiftable relationship to, the base, direct drive motors and opposed disks therefor and means for rocking or oscillating the disks and motors toward and away from the work and thus over the surfaces to be treated, one of the disks being delimited to a shorter stroke and the other passing through a deeper stroke, said machine also including novel delimiting means operable with the shiftable work holding assembly to alternately delimit the working stroke of first one of the disks and then the other disk upon shifting thereof with the work holding assembly.

Other objects and advantages of the invention will become apparent from th following description and accompanying drawings in which:

Figure 1 is'a front view of a machineembodying my invention;

Figure 2 is a top plan view of the machine shown in Figure 1 with certain parts broken away; Figure 3 is a side view of the machine taken from the right-hand side of Figure 2;

Figure 4 is a fragmentary. crossesectionalview taken on the line IVIV of Figure 2;

Figure 5 is a fragmentary cross-sectional view taken on the line V-V of Figured Figure 6 is a fragmentary detail viewof the motor mounting and delimiting device;

Figure 7 is a fragmentary plan View of certain parts of the device showing-the relative positions of the surface treating implements;

Figure 8 is a view similar to Figure"? showing the succeeding positionof the implements;

Figure'9 is a fragmentary transverse sectional view showing the position'of certain of the parts delimiting one of the implements to a short stroke; and

Figure 10 is a view similar to Figure 9 showing the position of the parts when one of theimplements passes through a longer stroke.

It is .to beunderstood that the embodiments shown herein may be varied or modified without departing from the spirit and scopeof the invention assetforth in the appended claims,

Referring particularly to Figure 1, the device generally consists of a base provided with a superstructure including vertical-standards 2| extendingupwardlyfrom the rear sidethereotthese standards being bridged at their upper ends by a cross piece 22. y

The base 20 and the upper cross piece or bridge member 22 servesto support the grinding assembly which includes a pair=of motors 2 3 and 24 directly connected-to a pair of grinding disks '25 and 26,-respectively, through drive shafts Z'I-and 28 respectively.

As will be explained presently, the motor 23 and 24, together with their appurtenances, are rockingly. mounted on the base 20 to be moved forwardly-and rearwardly, independently of one another to perform a surface treating operation. As will also be explained in detail presentlythere is provided a work Lholding'structure shown generally at.29 which is laterally, slidabl mounted upon the baseZUand is thus movable laterally relative to the surface treating assembly to suecessively expose varying surfaces of the work piece 33 to the surface treating operation.

It is'to be understood that the various specific details and the structural features utilized in the present embodiment of my invention, while highly satisfactory for accomplishing the purposes of my invention may be varied, and certain other mechanical expedients may be used which also utilize the general principles of my invention.

The base 20 shown herein is essentially box-like in formation and is made up preferably of four heavy sheet steel plates which providea neat, easily maintained, rigid supporting structure. Referring specifically to; Figures 3 and 4, it will be seen that there is suitably secured to the'upper,

'- upper end of the depending part 34.

presently, serves to slidably retain the work holding assembly 29 in the assembly shown.

As will best be seen from Figure 4 the work holding assembly 29 is slidably secured to and maintained upon the base structure 20 by means of a supporting member 33. This supporting member 33 includes a downwardly depending flange part 34 which overlies the upper part of the rear surface of the cross plate 32, there being a shoulder 35 formed in the member 33 at the This shoulder slidingly abuts against the upper edge of the 'plate32 which serves as a sliding track therefor.

The-member 33is-also provided with an intermediate heavy portion 36 and a generally obliquely disposed, upwardly and outwardly extending portion 31.. It will be seen that the outer "surface of the enlarged portion 36 is in a plane lying outwardly of the outer surface of the plate member 32 and thus a pair of vertically extending braces 38may have the adjacent portion of their inner edges welded to the outer surface of the enlarged portion 35 of the -member 33 as shown at 39 in Figure 4.

These brace or supporting members 38 are pref erably wider at the upper end and tapered rearwardly toward the lower end thereof, whereby the lower ends may be slidingly fitted behind a holder .3 attached to the front plate 3| of the base 20.

The work holder 29 itself includes a sleeve 4| non-rotatably mounted in an upstanding plate 12 which is secured in turn to a horizontal plate 43. Within the collar or sleeve 4| is rotatably and non-slidably mounted a shaft 44 having at its outer end a handwheel 45 and at its inner end 7 a plurality of sets of graduated threads 46 which side of the front base plate 3.1, as by welding or the like, a cross plate 32 which, as will be seen are adapted to be screwed into the threaded end of a fitting to be worked upon and also to be removed from the fitting by rotation of the handwheel45, The plates 42 and 43 are secured as by welding or thelike toa platesuch as'that shown at '4'! in Figure .4, the plate 41 being disposed between the supports or braces 38 and being pivotally secured thereto as by apin 48.

With this constructionit will be seen that the threads 43 together with the fitting .33 secured thereto may be rocked into an upright position such as shown .by the dotted lines in Figure 4, this rocking movement being about the pin 38 and being limited by bolt 41a inplate 41 which-engages the edges ofsupports 38. When in this position the fitting may be exchanged for anotherto be subsequently worked upon. Thereafter the operator, after he has turned the handwheel idsuificiently to secure the fitting tightly on its respective set of threads 46, may rock the entire assembly on the plate 41 forwardly into the position shown in full lines in Figure 4.

To the end that this forward rocking movement may be delimited to the desired degree there is provided herein on the oblique portion 31 of the member 33, a pair of opposed stop members each of which includes a portion 49 terminating inwardly in vertically disposed plate sections 50 which are each preferably aligned tosupportingly abut one of the bossesSila of the fitting 39 being worked upon.

The portions 43 of thedelimiting members are preferably maintained upon the oblique portion 31 ofthe supporting member 33 by means .ofsuitablebolts 5i the shanks of whichextend through laterally disposed slots 52 in the member 37. Thus, when the nuts53 of these bolts areloosened, the plate portions 50 may be drawn closer toward one another or spread further apart in mounted upon the angle member made up of plates 42 and 43, the shaft member 44 rotatably mounted in the sleeve and carrying the manipulating hand or wheel 45 and threads 46, all of which are mounted upon plates 41; which assembly is in turn pivotally secured as at 48 between the braces 38, and the upstanding plates 50, the latter being of less thickness than the bosses 30a of the fitting and being aligned therewith.

.For purposes to be described more fully pres-, ently, it is desirable. to first grind the opposedsides of one of the bosses 30a of the fitting and then subsequently to shift the entire work holding mechanism 29 to bring the surfaces of the other boss into alignment with the path of the surface treating implements and 26. Accord.- ingly, it will be seen that movement of the above described assembly laterally will accomplish this purpose.

Such movement is attained herein by means of an eccentric assembly 54 shown best in Figure 1. This assembly includes a disk 55 rotatably mounted at its center as shown at 56 to the plate 32 mounted at the upper end of the front plate 3| of the base 20. This disk is provided witha crank handle 51 by means of which it maybe rotated as desired. Connected off center of the disk 55 as at 58 is one end of a pitman 59, the other end of which is pivotally secured as at 60 to the outer face 36 of the enlarged portion of the member 33 slidably mounted upon the plate 32 as previously described. Preferably a stop bracket 5! is bolted to the outer surface of the plate 32 in such a position that it engages the pitman 59 to precisely position the respective bosses a of the tool in readiness for surface treatment in a manner to be described presently.

In Figure 1 it will be seen from the misalignment of the center of the handwheel 45 with the grinding disks 25 and 26 that the left-hand boss 30a of the fitting is aligned therebetween. This position is identical to that shown in Figure 2. After the grinding or finishing operation has been performed on the left-hand boss in a manner to be described presently, it will be seen that movement of the handle 51 of the eccentric disk 55 in a counter-clockwise position will shift the supporting member 33 together with the work holding assembly 29 described above, to the left, whereupon the right-hand boss 30a of the tool is brought into alignment to be worked on by the disks 25 and 26. During this movement it will be seen that the pitman 59 has had the right-hand end thereof raised and moved to the left, whereby it has moved these parts as indicated 1 To the end that the fitting 30 may be held tightly in its horizontal position as shown in Figures 2, 3 and 4 and so that the fitting will not shift under the influence of the action of disks 25 V and 26, there is 'provided an arm 62 having a handle 63. This arm is mounted upon a vertical member 64 which is pivotally secured through a boss 65 formed in the obliquely disposed portion 31 of-the supporting member 33. The remote end of the arm 62 is preferably curved as'shown at 66, this curved portion overlying the upper side of the fitting to hold it tightly down in its horizontal'position and into its abutting engagement with the respective plates 50 which underlie each of the bosses 30a. 1

When the surface treating operation is completedthe operator merely swings the handle 83 outwardly, whereupon the remote end of the arm 62swingsout of its overlying engagement with the fitting to permit the manipulation .of the handwheel 45 and the appurtenant parts, together with a fitting. into the vertical position shown in dotted lines in Figure 4. As indicated previously, the motors 23 and 24, together with their respective grinding disks 25 and 26 are mounted in the mechanism so that theymay be swung forwardly and rearwardly tocarrythe respective disks "through an oscillatory working stroke against the respective surfaces of the bosses 30a of the fitting 30 being worked upon. As will best-be seen from Figure 3 the side plates 3la of the base 20 are each provided with a centrally upstanding portion 61 through which extends a rocking rod assembly for the motors. This rocking rod assembly as best shown in Figure 4 includes a rod 68 which is provided with an operating lever 10 that is suitably keyed thereto. This rod 68 extends entirely across the machine as best shown in Figure l. Rocking movement imparted to the rod 68 by manipulation of the lever 10 is imparted to the motor 23 and the respective disk25 by virtue of the mounting arrangement for that motor and the association thereof with the rod 68.

To this end the motor 23 is mounted upon a generally L-shaped mounting element 1| having a vertically extending leg portion 12 disposed on the outside of the base 20"and a substantially horizontal motor receiving portion 13 extending inwardly over the left-hand side of the base as viewed in Figures 1 and 2. The motor 23 is pro-'- videdwith the usual mounting lugs 14 which are secured, by means of bolts 15 to the horizontal portion 13 of the mounting member H. The mounting member H is supported in the position shown by virtue of the extension 'of the remote end of the rod 68 through the skirt portion I2 thereof as shown best in Figure l. The rod 68 being enlarged as at 15 to maintain the attached relationship and preferably the rod 68, is keyed to the mounting member'll in any suitable manner so as to permit a slight lateral movement of the motor 23 and its mounting member N thereupon. If desired, suitable means may be provided for rockingly supporting the inner portion of the horizontal member 13 such as, for instance, the inner end thereof may be bent downwardly and recessed to receive the upper portion of the rod 68. With such a construction it will be seen that the parts are entirely open and thus may be easily cleaned and maintained and at the same time the mounting member H is keyed to the rod to be rocked forwardly and rearwardly by movement of the handle III while the mounting member II together with the motor 23, mayslide laterally for purposes to be described presently.

The motor 24 is similarly mounted in that it is secured by means of mounting lugs 11 to a horizontal portion 18 of a'rockable mounting member 19 having a downwardly depending part similar to that shown at 12 in the case of the mounting member "II for the motor23. In order that the mounting member 19 together with the motor 24 may be rocked forwardly and rearwardlyindependently oi; heu-inovement'ei the motor iii-and in o d that in. motor 24 withits. m untins member 79 may shif s ightl t ally 119011 i s g mechanism. the d pen i g por n 80 of themour tin mernb r 19 is adapted to, ro atebly receive the rod 68. In this instance it is to be noted that the mounti g member is n t k ye to the rod 68 t may reek iree y t a may shift s g ly laterally there In th s p rtion of thea s m ly there is pr vi d ma ipulating handle 82qw'hieh is s cur ly ted to t upper ortion of. the d ding section 80 of the mounting member 19. Thus it will be seen that rocking movement imparted tothe lever 82 will directly e fe the mou t ng member 9 and ro the am freely up n therodfifl, If desired, the inner p rtion ofthe hor zontal section 18 of the mounting memb r .19 may e eonst ue edto supeerting y abut an inward; aligned p r otthe edfiii the manner previously des ribed in coniunetion with the h r zonta p rti n 13 f the mounting member 1!. Y

Fr m t e fo e oing it w ll be seen t at t r is provided ein an pparatus in l ding a a 20 upon w ch is moun eda work holdin me h rosin-29. this Work h ding me anism being eoiprocable'laterally in the apparatus relative to the-base to dispose various parts of the work successively in a pOSitiOnto have thesurfaces thereof oufied, ground 'orpolished. will be seen from Figure- 2, when the eccentric mechanism, 54 is in the position shown in Figure 1, the left-hand bosstw of efitting 30 is aligned between the grinding disks 25 and 2 6. After the grinding or other surfacing operation has been performed in a manner to be explained presently upon the last mentioned lug, it will be seen that the handle 51 may be manipulated as previously described, whereupon the other lug 30a, is brou ht into oprratin position and disposedbetween the disks 25 aud t. Thereafter the operation may be re.- peated upon this second lug. Alsoit will be seen that there is providedherein a stationary b'ase upon which the motors together with their respective disks are mounted for rocking forwardly and'rearwardly to perform the surface treating operation, this rocking operation being independent in eachof, the respective motors and disks, It will also be "seen that a slight amount of lateralplay-is permitted between the rocking bar 68 and the respective motors, thus permitting an eificient grinding orbutfing operation in a mannerto be explained presently.

To the end that the motors '23 and 24 may be additionally supported and also to the end that the motors, togetherwith their respective disks may be urged resiliently toward one another during the grinding, bufilng or polishing operation, each is provided with a hanger 83 and 84 respectively. These'hangers are arranged to swingingly engage in suitable apertures in opposite ends of the respective motors and are each provided with ofiset portions 85 and 86 in the bridging portions thereof respectively, I

-"he' ged in. the fisetstt and 6 are raphl ng elements 8! and 88, respectively which comprise the lower ends of springs 89 and 90 respectively. These springs are each provided with bolts 9! and 52 respectively at the upper ends thereof which are formed to grapple the cross bar 22 of the super structure of the apparatus. From Figure 1 it will be seen that the bolts 9| and 92 are secured to the respective springs by nuts 93 and 94 which, when rotated, will progress upwardly or downwardly on he respective bolt tov vary the tension of the respeeti-ve spring. The c oss piece 22 of th sup r tr cture s rovided with a plurality'or apertures 95 in the upper side thereof, these apertures being' arranged to receive suitable pins such as those shown at 96 which serve to retain the upper ends of bolts 92 inwardly of the lower ends of the spring. Further adjustment. oi'the tension or the springs and particularly of the tendency thereof to d aw the motor and the respective dis s .5 and 26 inwardlytoward one anot er and a ai st the work may be accomplished by setting t e pin 96 into holes nearer the center of the cross piece 22 or into outwardly disposed holes 95,

ith the foregoi g nstructio it i l b seen that se ral ad anta es are deri d y the s in rra g me t shown he ein.- rst, the s in s tend to uppo t he mot r and. thus r e th pe t oi much ii'ert in mo ing th same r ing the mani ulatio or handl s 1. a d 82 to r ck t e motors and he disk towa d a d away r m the wo k, In o her wordst prin s b la ga s he We ght r th m t rs nd. i s- Se ond, the springs, when the mQUOl'S in their rearward position and at rest as shown in Figure 3, permit the disks 25 and 26 to spread slightly apart from one another and also tend to urge the disks toward one another as tension thereon is increased by forward movement of the motors and disks into operative position. The practical advantage of this feature of the spring assembly is that the disks tend to abut the surfaces of the respective bosses resiliently and thus are spring pressed, in eifect, against the surface being worked upon rather than being rigidly mounted so as to cut off, in a single stroke, a certain thickness progressively from the surface being worked upon. This feature has been found to accomplish the desired results very effectively and yet greatly increase the life of the surface treating implements particularly if the implements are grinding wheels as disclosed herein.

It will be seen that in View of the lateral play of the motors and the disks during the surface grinding operation, and due to the resiliency imparted to the contact between the disks and the work, some means must be provided for delimiting the inward movement of the disks toward one another under the influence of the springs so that the depth of the grinding is delimited to a desired degree, thereby leaving the finished lug 300. with a predetermined thickness.

To this end each of the downwardly depending portions l2 and of the motor mounting members H and 1'9 is provided with a stop bolt 9'! each of which is provided with a lock nut 98, whereby it may be secured tightly, in a given, set position. Thus it will be seen that if the nuts 98 are loosened and then the bolts 91 are each screwed outwardly a slight distance the springs will be enabled to draw the motor mountings together with the motors and the respective disks inwardly to a greater degree, thereby to grind a greater depth from the surface of the bosses 3011 respectively, whereby these bosses are made thinner by the grinding operation. Likewise it will be seen that if a lesser depth is to be ground from the surface of the bosses or a l ghter polishing pressure is desired. he bol s 9'! may be screwed further inwardly of the re pective parts on which they are mounted. Thus the inward movement of the'motor mountings, and the, motors together with their disks unde the influence of the supporting springs 89 and ,90 is delimited. It will be understood of coursetllfi t the bolts 91 may be calibrated in any suita le manner whe eby predete m ned d s a s between the working faces of the disks may be obtained quickly and easily. From Figure 1 it will surface treating positionsuccessi'vely; for successive grinding, polishing or bufilng operations. There is also included, a nov'elarrangement for opposed grinding, buffing, or polishing disks, these disks being movable forwardly and rearwardly, into and out of surface treating position andyet beingdriven by a direct drive from a respective motor. The arrangement also includes means for permitting a certain amount or play in the disks and yet resiliently urging the disks toward oneanother a predetermined, regulated amount which is delimited when the desired thickness of material has been ground from the device being worked upon or when the bufi'ing or polishing pressure ha reached a predetermined intensity. 1 Another aspect of the present invention is directed to increasing, the life of the working medium upon the face of the disks and 26. It

; will be understood that if "the width of the surfaces on bosses a as viewed in Figures 7 and 8 I are less than the radialdepth of the surface on the respective disk and the disks are moved forwardly into working contact with the device being ground only sufficiently far to utilize a peripheral margin of substantially the width of the surface being ground, then the grinding implement will deteriorate over this portion of the surface while the inner part thereof remains intact. Furthermore, as in the present instance, because of the yoked formation of the fitting 30, one of the disks (that grinding the outer surface of the respective boss) may move further forward than the oppositeidisk which i simultaneously grinding the inner surface of that boss.

If this condition prevails for each of the successive grinding operations, it will be seen that one of, the disks will likewise be worn only at the outer peripheral part thereof, while the other is "worn more evenly due" to the further progressive movement thereof over the outer side of the boss.

It is this condition which i availed of in the present invention to increase the life of both the disk by an alternating arrangement to be described presently. Thi alternating arrangement, 'it is to be noted, permits each of the opposed grinding disks to be subjected alternately to. different grinding strokes and thus, while the successive stroke of each disk is different, the alternating from one character of stroke to the other results in an overall operation, whereby each disk is utilizing its entire surface during the grinding cycle and each is passing through a cycle identical to the other so that one does not wearbefore the other nor does one wear unevenly as to the other.

To the end that the oscillating, working strokes of the disk 25 and 26 may be alternated as above described, there is provided herein as best shown in Figures 7 and 8, a pair of spaced rocking arms 99 and I00. Thesearm are weighted at their outer ends as shown at IOI and I02 and are rockinglysecured on rods I03 and I04 respec:

tively, which extend therethrough. To th en that the arms 99 and I00 may not shift laterally upon the rods I03 and I04, sets of stop pins I05 and I06 are arranged on each side thereof respectively. The weights IOI and I02 are of uch magnitude that they tend to rock the arms into a position shown in Figure 4, thereof are elevated.

As best shown in Figure 1 the rods I53 and I04 are welded to the laterally slidable work supporting assembly 29 as at 'I03a and Wild respectively.

It will'be noted that the arms 99 and I00 are spaced apart a distance less than the distance between the forwardlyfinclined edges 3l'b at the upper part of. side panels 3M of thepedestal or support 20. The spacing between the arms 99 and I00 is such that when thetwork holding assembly 29 is shifted to the right as shown in the drawings, the arm I is in alignment with the right-hand 'side'or panel 3Ia and thus in alignment' withthe stop nut '3Ic protruding from the respective inclined surface 3Ib. On the other hand, when the Work holding assembly 29 is shifted to the left in order that the disks 25 and 26 may operate upon the other lug of the fitting, the positions of arms 99 and I00 are reversed in that the arm I00 is drawn out of alignment with the respective stop nut 3Ic while the arm 99 is moved into alignment with its respective stop nut 310 at the left of the apparatus By reference to Figures 3, 9 and 10, it will be seen that when the arm I00 is aligned with the respective side wall or panel 3Ia as shown in Figure 9, it will serve as a. stop or wedge between the respective stop nut 3Id and the respective motor mounting base 'I8 t0 limit the forward movement of the respective motor and disk under the influence of manipulation of the handle 10. As will best be seen in Figures 9 and 10,the

disposition of bolts lfl'lthrough the ends of arms 99 and I00 permits a variation of the limited strokes of the respective disks depending upon the degree to which the bolts are screwed into or out of the ends of the respective arms. As will be seen in Figure 10, when the arm 99 is in the positionin Figure 7 the bolt I0'I thereof will not beinterposed between the respective motor base. I3 and the respective inclined surface 3Ib and thus manipulation of the lever 82 will enable the disk 25 to be rocked forwardly into an extreme position as shown in Figure '7 so that the surface treating operation will be accomplished over the radially inner portion of the abrading surface thereof. Thus it will be seen that in the first of two successive operations required to surface both of the bosses 30a of the fitting 30, the innerporticn of the disk 25 will be utilized while the outer portion of disk 26 wil1tbe utilized by virtue of the interposition of the end of arm I00 between the motor base 10 and the upper; forcarried arms 99 and I00 to the left' also, whereby arm 99 is now brought into alignment with the respective side panel 3Ia, while the arm I00 is moved out of alignment withits respective panel 3Ia so asto be forced into the extreme lower position by oscillation of the motor base I8 siml-f 'lar to the position of arm 99 as shown in Figure 10. j'Thus in this instance and as shown by the wherein the inner ends on said work holding assembly to move laterally r therewith, and abutment members for engaging said stop members, said abutment members being so spaced that only one thereof is in-alignment with the respective stop member for each lateral position of the work and so that the other is in alignment with its respective member when the work holding assembly is shifted laterally for a successive operation upon other surfaces of the work piece, whereby each motor and the respective surface treating member thereof passes through alternate limited and long strokes when rocked into surface treating engagement with the work piece. a i

3. In a surface treating machine, a supporting assembly including a base, a work holding assembly including means for mounting the same laterally slidingly on the base and a surface treating assembly including a plurality of motors 'mounted in axial alignment and tomove forwardly, independently of one another and having surface treating members mounted on the shafts thereof in opposed spaced relationship to receive a work piece therebetween so that a plurality of opposed surfaces on said work piece may be treated simultaneously, independent, rock- 'in'gly supported mounting members for each of said motors, a stop assembly for alternately delimiting the rocking movement of said mounting laterally for a successive operation upon other surfaces of the work piece, whereby each motor and the respective surface treating member thereof passes through alternate limited and long strokes when rocked into surface treating engagement with the work piece, and means for urging said surface treating members resiliently toward one another and against opposed sides of the work during the surface treating operation.

4. In a surface treating machine, a supporting assembly including a base, a work holding assembly including means for mounting the same laterally slidingly on the base and a surface treating assembly including a plurality of motors mounted in axial alignment and for forward and rearward rocking movement and having surface treating members mounted on the shafts in opposed spaced relationship to receive a work piece therebetween so that a plurality of opposed surfaces on said work piece may be treated simultaneously, means for delimiting the forward movement alternately of one and then another of said motors during surface treating strokes thereof including a pair of limit members arranged to slide laterally with said work holding assembly, one of said limit members being aligned with each of said motors, said limit members being so spaced and arranged that in one position of the work holding assembly one of said limit members serves to delimit the stroke of the respective motor and in another position of the work holding assembly another limit memberidelimits the stroke of its respective motor, said first named limit member then affording full oscillatory movement of its respective motor.) V

5. In a siufacetreating machine, a work-holding assembly for inaintaining a work piece in a position to be treated; asurface treating assembly including axially aligned motors each having a surface treating; disk member on- ;the shaft thereof, each of said disk members being disposed in facing, spacedopposed relationship, said work holding. assembly" being arranged to maintain a' w'orkpieceso-tlfat-opposed surfaces thereof are aligned between, said'disks, means for. mounting said motors and said: disks for. oscillatory motion toward and away from said work piece, whereby.

alternately,'whereby each disktravels through a shorter and a longer stroke alternately with'each succeeding surface grinding operation. i

' i 6. In a surface treating machine for treating opposed surfaces of an article, a pair of axially aligned motors having surface :treating disks disposed "at-the ends 'of'the shafts-thereof, said disksbeingarrang'ed in spaced, facing relationship, meansfor'mountingsaid motorsand said disks for forward and rear oscillatory movement, a Work holding (assembly onsaid machine mounted in laterally slidable relationship'thereto andme'ans for 'movin'g said work holding assembly laterally to'a'fford disposition of one set of opposed surfacesthereofin registration with the space between said disks and subsequent disposition of another set of surfaces thereof in registration with said space. 1 7. Iri' asurfacetreatingmachine for treating opposedsurfaces of an article," a pair of axially aligned motdrs' having surface treating disks disposed at theendsof the 'sha'ftsther'eof, said disks being arranged in spaced, facing relationship, means "for mounting said motors and said disks for forward and rear oscillatory movement, a workholding assembly on said machine mounted in laterally slidable relationship thereto and means for moving said work'holding assembly-laterally to afford disposition of one set of opposed surfaces thereof between said disks and subsequent disposition of another set of surfaces thereof between said disks, and means for resiliently urging said disks toward one another to afford resilient surface treating abutment thereof with said surfaces of the object to be treated and whereby each disk serves as a backing for the surface treating operation of the other.

8. In a surface treating machine, a work holding assembly for securing a work piece in a rigid position while opposed surfaces thereof are being ground or the like, said work holding assembly including a shaft upon which said work piece may be rigidly mounted, said shaft being arranged to be pivoted intoa substantially vertical position to afford application and removal of the work piece and being also arranged to be pivoted into a horizontal position whereby a set of opposed surfaces thereof are in position to be work piece, a pair of opposed-surface treating disks and a source ofpower directly-connectedto each of said disks, each source .of. power. and each disk being mounted for independent oscilla tory movement toward and awayfromthework piece, means for supporting the work;piec in.- eluding, plate membersdisposed p one side of the forks of said bifurcated-.element, -said plate members being less than theithickhessl of .the forks supported thereby to aiford, oscillation .of the surface treating elements along thesurfaces of said forks without obstructing said surface treating elements.

lOPIn an apparatus, for treating-the, surface of bosses disposed on the .forks ,ofrabifurcated work piece, a pair OfA'OPPQSBdi SUIfZ'OE treating disks and a source of power. directly rconnected to each of said disks eachsource of,power'andeach disk being mountedyfor independent oscillatory movement toward and away from-the workpiece, means for supporting the workpiece including plate members disposedononesideofthe forks of said bifurcated element, said -;plate imernbers being less than; the thickness of;. -=the ,forks ,supported thereby to afford-oscillation of the sure face treating ,el'ements aiong the surfaces of. said forks without obstructing saidlsurface; treating elements, said plate-like members being mounted for lateral movement to afford supportsfor work:

pieces having forks disposed in varying ,{spaced relationship.

11.. In asurface treating .machine for treating opposed surfacesof an.-article,,a pair of aligned driven shafts, surfacetreating toolsdisposed at thereof 11inv registration with; the space between the ,toolsand subsequent disposition of another set- :of surfaces thereof in registration with said space, and means for resiliently urging said tools axially toward one another to afford resilient surface treating-abutment thereof with the set of surfaces of the article to be treated and whereby' ach tool serves asa backing forthe surface treating operation of the other tool.

13. In a surface treating machine for treating opposed surfaces of an article, a pair of aligned driven shafts, surface treating tools disposed at the ends of the shafts, said tools being arranged in spaced, facing relationship, means for mounting said shafts .and said tools for oscillatory movement, into and out of working. position, a work-holding assembly on said machine mounted to travel substantially parallel to said shafts, means for moving said work-holding assembly to afford disposition, of one set of opposed surfaces thereof in registration with the space between the tools and subsequent disposition of another set of surfaces thereof in registration with saidspace, and means for resiliently counterbalancing said shafts, tools, and mounting means tofacili-tate the oscillatory movement thereof.

14 .In a surface treating machine, a pair of opposed surface treating members adapted to work on respectively opposite sides of a work piece disposed therebetween, a driven shaft and shaft supporting means for each-of said members mounted for independent oscillation transversely of the shafts and also relative longitudinal movement thereof with the treating members, an overhead frame structure, and spring members suspended from said framevstructure and con- S. PEARSON.

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