US1820735A - Grinding machine - Google Patents

Description

Aug. 25,1931.

w. F. FRASER GRINDING MACHINE Filed Sept. 15, 1926 4 Shegts-Sheet 1 9 a NQQ , INVENTOR. E Fraser BY E E Warren ATTORNEY.

Aug. 25, 1931. w. F. FRASER GRINDING MACHINE Filed Sept. 15, 1926 4 5765179511661 2 INVENT0VR. Warren 1". Fraser BY} A TTQORNEY.

Aug. 25, 1931. w. F. FRASER 1,820,735

- GRINDING MACHINE Filed Sept. 13, 1926 4 Sheets-Sheet 3 [NVEN TOR. Warren E Fraser BY M A TTORNE Y.

Patented Aug. 25, 1931 WARREN r. FRASER, or'wns'rnono, uassnonnsn'rrsy enrnnmo MACHINE I Application filed September 13, 1926. serial No. 134,957, i

This invention relates to improvements in machines for performing a grinding, polishing or like operation, and more particularly to machines of this type which are constructed to perform their various functions automatically.

Various automatic machines have been developed heretofore but their utility has been restricted due to their construction and prim p10 ciple of operation. It has been common in such machines to drive or rotate the work by rotatable supporting means exerting an end pressure thereon. For this reason such Inachines have not been satisfactory for grinding or polishing fragile objects of hollow thin walled construction of the type of automotive pistons. If excessive pressure is applied upon the ends of work of this type, the work often is distorted. While a; cylindrical surface may be formed upon the work during the grinding operation, nevertheless, when the work is removed from the machine there is a tendency to spring into a distorted form due to the release of the excessive end pressure.

It is one object of the invention to overcome these difficulties and to provide a ma chine constructed and arranged for supporting and driving work so that it may be ground to the desired shape and size without danger of distortion.

It is a further object of the invention to construct and arrange the supporting and rotating mechanisms so that certain types of work which could not be handled conveniently in machines as constructed heretofore may be supported and positively rotated against the tangential thrust of grinding.

Heretofore, it has been deemed impossible to grind satisfactorily on an automatic cylindrical grinding machine various types of work of large size and peculiar construction, such as pistons and the like of a more or less fragile nature, inasmuch as no satisfactory arrangements had been provided for feeding work to and from the machine.. It is essential in certain grinding operations that the work be finished with an accurately ground surface and such work could not be handledconveniently by dropping and sliding from the holding and supporting member. Slidingoi fimshedjwork pieces into a container necessitates handling with extreme carc to revent undesirable contact between one fin-- rshedpiece of work and another which might mar their highly finished surfaces.

It is another obj ect of the invention to pro vide mechanism for feeding'and conveying a piece of work to a Work supportlngmernbe'r without stopping the machine, and thereafter removing the finished piece of work from the carrier preferably automatically without marring or injuring the surface of the work.

In accordance with the invention ama chine is provided comprising a rotatably mounted wheel adapted to perform a polish? Ing, grinding or like operation and which is hereinafter referred to as a grinding operation. This wheelis' constructed and arranged to move toward and away from the operative grinding zone to bring'the work to size and thereafter permit dischargothereof. A mechanism, which may include'a tur ret wheel, is provided for feedingsuccessive .work pieces separately into theg'rinding zone. In the grinding zone the work is taken up by a yielding supporting member and held during the grinding operation independent of the conveying mechanism, at

which time a positively rotated driveris brought into contact with a projection upon the work for rotating the same, After the grindin operation is completed,'the driver is withdrawn andthe'work released to the conveying mechanism and brought to a" point where it may be automatically discharged. The'invention will-be more clearly understood from the followingdescriptionin con junction with the accompanying drawings; in. which, v

Fig; 1 is a plan view of grinding machine embodying the invention; Fig. 2 is-"an' end elevation of the same as viewed from one side of the machine; i

Fig. 3 is an end elevation asfvi-ewed from the opposite side of the machine;

Fig. 4 is a partial section 1 elevational view Fig. 5 is a fragmentary sectional View through a piston while in operative relation to the driver and grinding wheel of the machine; and

Fig. 6 is a View of a modified form of work supporting and driving member adapted to engage projections on the work or to enter recesses therein.

In the drawings I have shown a machine embodying and illustrating the invention comprising a base 1 provided with slideways 2 for a slide 3 movable thereon. The slide 3 is constructed with suitable bearings of any well known construction (not shown in de-, tail) for rotatably mounting a spindle 4 upon which a wheel 5 of suitable polishing or abrading material is mounted. The wheel 5 may be rotated at. a suitable speed for polishing or grinding by anydesired means, such; as a pulley6 mounted on spindle 4 and driven in any suitable manner, such as by a belt, from any convenient source of power. A main drive shaft 8 for actuating the various mechanisms of the machine is mounted in suitable bearing surfaces 9 in the base 1 and is provided with a pulley 10 suitably-secured thereto and adapted to be rotated from any convenient source of power, such as by a belt.

In the machine illustrated the wheel 5 may be moved toward and from the work to grind the work to a predetermined size. For this purpose a grooved cam 12'is mounted upon the main drive shaft 8. for rotation therewith and is provided with a groove 13 adapted to receive a follower roller 14 suitably mounted upon the end of one arm of a bell crank lever 15 which is pivotally mounted upon a shaft 16. The outer end of the other arm of the bell crank lever is provided with a slot 17 adapted to engageapin 18 on a depending portion 19 of a slide 20 adjustably mounted upon slideways 21 in the base 1. The slide 3 may be adjusted relative to the slide 20 to change the position of the operative surface of the wheel 5 by an adjusting screw 22 engaging a threaded hole 23 in the slide 3 and appropriately secured against endwise movement in an upwardly extending boss 24 on the slide 20 by a collar 25 between the boss and a shoulder on the screw and by a hand wheel 26 appropriately secured upon the end of the screw and engaging the boss.

In accordance with the-invention the work to be ground is supported for rotation so as to minimize distortion during grinding. One suitable construction for this purpose may comprise spindles 30 and 31 rotatably mounted in bearing surfaces 32 and 33 in brackets 34 and 35 respectively attached to the base- A driving pulley 36 is secured upon the spindle 3O bya set screw 37, and is mountedthereon between the bearing sur-. faces '32 so as to prevent axialmovement of the spindle. A pulley 38 likewise issecured upon the spindle 31 by a set screw 39, and is an automotive piston; and the member 43 is provided with center for engaging a center hole 45 in the work.

A rod 46 having a driver 47 at one end thereof is positioned within the opening 40 and is mounted for rotation within a hearing 48 on. a bracket 49 integral with or otherwise appropriately secured to bracket 34,1and is provided with a key 50 engaging a slot 51 in the member 42for operative connection with the pulley 36. r In order that the rod 46 may be moved axially relative to the work supporting member 42 to bring the work driver 47 into contact with aprojection within the work, :a pair of collars 52 are adjustably mounted uponthe rod by set screws 53 on either side of a yoked portion 54 of a lever 55, pivoted to swing in a horizontal planeabout the stud 56 in the basel, so that any movement of the lever is transmitted to the rod. The lever 55 is held yieldingly against an adjustable stop screw 57 in the bracket 34 by a spring 58 extending between a pin 59 on-the-lever and a pin 60 on a bracket 61, thereby holding the work driving member 47 in any desired position. 7

The work driver 47 may be retracted from engagement with the work to permit discharge thereof. In the construction illustratedthis may be accomplished by a mechanism operating automatically intimed relation with the other mechanisms of the machine. Thus, a lever -pivotally mounted uponastud 71 in the base of the machine is provided at one end with a roller72 adaptedto engage a groove 73 in a cam 74 secured upon the main drive shaft 8. The other end of the lever 70is provided with a forked portion 75 adapted to engage the pin 76 on a collar 77 .adjustably mounted by means of a set screw-78 upon a shaft 79 which in turn is mounted in bearings 80 and 81 in the bracket 61 so that any motiontransmitted from the cam 74 moves the shaft 79 axially in its bearings. During the major portion of a cycle of operations, the shaft 7 9 is held out of contact with .the lever 55,'but] at intervals in proper timed relation with the othermechanisms the shaft 79 moves toward the left (as viewed in Fig. 1) ,and swings the lever'55 to withdraw the work driver 47' from. engagement with the work and move it into an inoperative position within the recess82 of the work supporting member 42. v

: One or both of the work supporting spindles 30 and 31 may be moved relatively towsrd'and away iron: each otherin timed relat-ion with the other mechanism to grip the work and support the same during the grinding operation and thereafter withdraw to release the work. In the construction illustratcd, the :1 indie is mounted for rotation without en wise movement, while the spindie 31 is constructed and arranged for both rotary and axial movement for thepurpose above referred to. The outer end oi the spim die 31. is provided with collars 84 and 85 held in position on the end of the spindle by a nut so and which are so constructed and arranged as to provide a groove for a collar 88 having diametrically positioned projecting pins 89 and 90. A lever 93, having yoked portions 94 and 95 adapted to engage pins 89 and 90, is pivotally mounted to turn about a stud 96 in the bracket 35, and is provided at its other end with a follower roller 97 adapted to engagethe operative surface ofa cam 98 secured upon the main drive shaft 8. A spring 99, which is secured at one end to a pin 100 on the yoked portion 94 of lever 93 and at the other end to a pin 101 on the bracket 35, serves to hold the roller 97 upon the cam 98 as Well auto yieldingly support the spin die 31 and member 43 against the work. The cam 98 is provided with a raised portion 103 arranged so that the spindle 31 and member 43 may be withdrawn from the Work in timed relation with the other mechanisms of. the machine after the grinding or polishing oper ation has been completed and the wheel 5 removed therefrom. w

A suitable mechanism for feeding successive workpieces separately into the grind ing zone and for conveying them therefrom after the polishing or grindingoperation has been performed may comprise, as illustrated,

' a turret wheel secured upon one end of a shaft 111 which is supported-for rotation in bearings 112 and 113'in a bracket 114 fixed to the base of the machine. Theturret wheel may be actuated intermittently in properly timed relation with theother mechanisms of the machine to feed work pieccsinto their opentire position'by. a mechanism comprising a Geneva plate-115 secured upon the. shaft 111 and operatively connected to a driving gear 116 suitably mounted on the main drive shaft 8 A gear 117 rotatably mounted on a stud 1 18 in the base of the machine arranged to mesh with the drive gear 116 and is constructed with anarm 119,. 1nt ral with or otherwise appropriately scour thereto, having a pin 120 at its outer end adapted to engage slots 121 in the Geneva plate to intermittently turn the plate and the turret wheel. A stop is provided to hold the turret Wheel against rotation except durlng the indexing period of movement and maycomprisea pgrtialcylindricalplate122 secured upon the arm 119 and adapted to mate with concave surfaces on the Geneva plate 115v when the pin 120 is not in engagement with one o'f-the slots 121. i n l .1

Thetu'rret wheel is provided witha lurality of openings 124 to receive successive pieces of work and convey them into r the grinding zone. Preferably, the turret wheel is provided'with spaced undercut arms 125 which are-substantially T-shaped and are so arranged as to provide partiallycylindrical openings into which thework pieces maybe inserted laterally. These arms are spaced to provide slots or spaces through which the work pieces may project into peripheral cons tact with the grinding wheel. Inthis (3011-. struction the work must be fed torthe' opens ings 124 in a direction parallel withthe axis of rotation of the turret and must leaye the'turret in a similar direction. Thisprevents the workifrom dropping out of the curret openings after leaving the grinding zone. The work blanks maybe inserted in the open+ ings 124 of the'turret by hand or by some mechanical device. If desired, a hopper or chute may be arranged to supply work'blanks automatically to the openings in the turret wheel as will be understood bythose skilled in the art. In order that the work blanks may be aligned so that they will be inproperposi-1 tion to be gripped by the work supporting members 42 and 43, a stop plate 126is secured to the bracket 61 for the work pieces torest against as they are inserted in the openings 125 of the turret wheel.

The finished ground or polished work pieces are carried by the turret wheel to a position for discharge diametrically opposite the grinding zone. Any suitable device may be employed to remove the work from the turret, such as an ejector 127 mounted on the right hand end of the shaft 79 (as viewed in Fig. 1.) The.camj74,preferably, is shaped and arranged upon the drive shaft 8 so as to move the upper portion of the lever 70 and shaft 79 carrying the ejector 127 toward the right (as viewed in Fig. 1), tov eject the work blank from its position in the opening 124 of the turret'wheel onto a, V-shaped trough or support. 128 while another work blank is being'ground or polished. 'p In Fig. 6 of the drawings af driver and work support of modified constrnctionis shown comprising a rod 130,corresponding to therod 46 of the machine illustrated in Fig. 4, within an opening 131 in a Work sup; port center 132 having a slot 133 for slid ably receiving a pin 134 in the rod130. .A workdriver 135 having lugs 136 for engage ing projections upon the work surrounds the Work center 132 and is operatively cons nected to the rod for rotation "therewith by the pin 134. As the main drive shafts isrotated, the arm 119 swings'so as to bring the pin 12O into engagement with one of the slots 121 causingthe turret wheel'110 t'o turn-s0 as to bring one of its work conveying openings 125 into the, grinding Zone just as'the' pin 120' leaves the slot 121. The spring 99 is arranged to actuate the lever 93 and cause the spindle 31 and work supporting member 43 to move at this moment to bring the center of member 43' into engagementwith the centerhole 45 of the work blank 44: and bring. said blank into engagement with the 'chamfered edge of the work supporting mem ber 42, thereby lifting the latter off the supporting surface of the opening 124. The cam 74 is shaped" and. arranged upon the shaft 8 so as to causethe rod 79 to move and permit'the spring 58 to move the lever -to the right (as. viewed in Fig. 1) and cause the driver 47 to move into position to engage a projection within the work blank to rotate the same. The position of the driver relative to the work may be controlled by the adjusting'screw 57.

' =When the work is properly supported and rotated in thismanner the wheel 5 moves into the'grinding zone in contact with the work, and'the cam 12 is so constructed and so arranged upon the shaft 8 as to cause the wheel 5 to move into the grinding zone at this time. The cam 12, preferably, is so'shaped as to impart a relatively fast approach of the wheel 5 towards the work and-then a slow gradual feed to properly size the work. After the grinding or polishing operation is completed, the wheel is moved rapidly out of the grinding zone.

' As-the wheel recedes from the work, the upper portion of the lever will move toward the "left (as viewed in Fig. 1) and withdraw the work driver 47 from its driv ing position in contactwith the work blank. At the same time the cam 98 actu'ates the lever 93 to cause the work supporting member 43 to recede from its operative position in' contac t with the end of the work and release the work from the supporting members, permitting it to rest within the opening or pocket of'the turret wheel.. By this time the pin 120 has arrived in a position to turn the Geneva plate-in the direction shown by the arrow in Fig. 3 a sufficient distance to remove the finished piece of work from the grinding zone and bring the next piece ofwork into the grinding zone.

' Themachines operates continuously and automatically in this manner to bring successive work pieces into the I grinding zone and 'convey ground work to a point for discharge. WVith each intermittent movement of the turret Wheel a finished work piece is brought to a position diametrically opposite the grinding zone for discharge, that is, after the first four movements after initially starting the machine. The ejector 127 is then actuated, when the plate 122 mates with the convex surface on the Geneva plate, to discharge the work, upon the trough of support 128. The operator ,periodically;inserts new. pieces of work in'theopenings of the turret wheel after they-leave the ejectingpo'sitions; The use, of a grinding fluid :forcooling the work during the grinding operation is well known and understood in the art. .Forthis reason, and in order not to: complicate the illustration of the invention,-Zno provisions have been described or illustrated for supplying such a grinding fluid. i Su'cha device may the work blank from the supports for rec'ep-' t-ion by the feeding mechanism, and means for positively ejecting said blank from said feeding mechanism after completion of grinding.

2. A grinding machine'comprising a-rotatably mounted grinding Wheel, a turret mechanism; for feeding successive work blanks separately into the grinding zone'and for conveying ground work to a point for discharge, rotatable suports for h'oldingwork in an'opera tive grinding position out 'of contact with the turret-mechanism, Isa-id turret mechanism being constructed and arranged to feed work to and convey it fromthe grindg ing zone in a lateral direction, means for re leasing work from its support in the grinding zone tothe turret mechanism, and means for positively ejecting ground work from" the turret in 'an'axial direction". v 3. A grinding machine comprising r09 tatably mounted grinding wheel, a work r'eceiving turret having spaced undercut arms arranged to hold a multiplicity of duplicate work pieces in the turret, said work pieces being insertable axially between the adjacent arms, means to turn the't'urret and thereby successively present work pieces in the grind ing zone, centering supports 5 for lifting work piece'from 'co'nt-act with the turret arms and accurately positioning-it during the grinding operation, and mechanism for mo v rel easing the work piece.

in" the centering supportsfor engaging and ite and thereby successively present Work pieces in the grinding zone, means for lifting a Work piece from contact with the turret arms and centering and rotating it during the grinding operation, mechanism for releasing the Work from said centering and rotating means for reception again by the turret, supporting means located near a work piece in the turret to receive the Work, and a device actuated in timed relation with the turret movement to eject each finished work piece axially from the turret onto the support when the Work has reached a predetermined position.

5. A grinding machine comprising a rotatably mounted grinding Wheel, centering members which engage a Work piece during its grinding cycle, a driving member slidably supported Within one of the centering members, means to rotate the driving member during the grinding cycle, means to move the Wheel cyclically towards and from the Work, mechanism actuated in timed relation with the grinding cycle to Withdraw the driving member from contact with the Work and into its centering member, and means to automatically release the Work from the centering members.

Signed at Worcester, Massachusetts, this 10 day of September, 1926. WARREN F. FRASER.

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