US2818689A - Grinding apparatus - Google Patents

Description

Jan. 7, 1958 M. A. JENNINGS ETAL 2,818,689 GRINDING APPARATUS Filed July so, 1956 1 s Sheets-Sheet 1 FIG.

4 INVENTORS MELVIN A. JENNINGS WESLEY JENNINGS BY V w ATTORNEYS 3 She'ets-Sheet 2 I l l NN v N o .1. m m MIN #T HM 8 4 ,4 NW;

INVENTORS MELVIN A. JENNINGS WESLEY JENNINGS any/52w.

Jan; 7, 1958 M. A. JENNINGS ET AL GRINDING APPARATUS Filed July 30, 1956 ATTOBbLYS Jan. 7, 1958 M. A. JENNINGS ET AL 2,818,689

GRINDING APPARATUS 5 Sheets-Sheet 3 Filed July 30, 1956 INVENTORS BY WES LEY JENNINGS ATTORNEYS MELVIN A. JENNINGS '7 has! GRlNDlNG APPARATUS Melvin A. Jennings, Vassar, and Wesley Jennings, Royal Oak, Mich.

Application July 30, 1956, Serial No. 600,777

18 Claims. (Cl. 51103) This invention relates to apparatus for use in conjunction with a grinding wheel and has for one of its primary objects the provision of means for presenting a workpiece to a grinding wheel, turning the workpiece relatively to the grinding wheel about the axis of the workpiece so that the entire surface of the workpiece adjacent to the grinding wheel is traversed by the grinding surface, and discharging the workpiece from the apparatus after completion of the grinding stage, all of the foregoing operations being accomplished automatically.

Another object of the invention isto provide apparatus of the kind referred to which includes yieldable frictional means for yieldably holding a workpiece against the grinding wheel and for simultaneously turning the workpiece relatively to the grinding surface.

Another object of the invention is to provide apparatus of the kind described which is adjustable so as to be capable of use with workpieces of varying size.

A further object of the invention is to provide such apparatus as has been described which is capable of presenting a workpiece to the grinding wheel at different positions relative to the latter so as to promote even wear of the grinding surface.

A further object of the invention is to provide automatically operable means for initiating the grinding of a workpiece and for automatically discharging a finished workpiece.

Other objects of the invention will be described in detail or will become apparent from the following description of the invention when read in conjunction with the appended claims and the accompanying drawings, in which:

Figure 1 is a side elevation of apparatus constructed in accordance with the invention;

Figure 2 is a top plan view on an enlarged scale of a portion of the apparatus shown in Figure 1;

Figure 3 is a sectional view taken on the line 3-3 of Figure 2; and

Figure 4 is a fragmentary plan view diagrammatically illustrating a modification of a portion of the apparatus.

Apparatus constructed in accordance with the invention comprises a frame 1 having supporting legs 2 on which is mounted a bed or upper plate 3. In the disclosed embodiment of the invention, the frame includes forwardly projecting arms 4 which may be secured by bolts 4a or the like to the supporting structure 5 of a grinding wheel 6 which is mounted for rotation about the axis of a horizontal shaft 7, the grinding wheel being shielded by a suitable hood 6a. Alternatively, the grinding wheel and its driving motor (not shown) may be mounted on the same framework that supports the remaining parts of the apparatus.

On the bed 3 is rigidly secured a base member 8 and slidably mounted on the base 8 is a lower guide plate 9 provided with an upwardly projecting dovetail 10 which extends laterally of the plate 9, i. e., parallel to the shaft 7 on which the grinding wheel 6 is mounted. Mounted for sliding movement on the lower guide plate 9 is an intermediate guide plate 11 which is provided in its under side with a recess or guideway 12 for reception of the dovetail 10. The upper surface of the intermediate guide plate 11 is provided with a dovetail slot 13 which extends fore and aft of the plate, and the slot 13 receives a mating dovetail 14 formed on the lower surface of an upper guide plate 15. The bed plate 8 is provided with an upstanding part 16 in which is rotatably journalled a shaft 17, the forward part of which is threaded as at 18 and extends through an upstanding part 19 provided with a threaded opening and formed at the rear end of the lower guide plate 9. The shaft 17 is equipped with a handwheel 20 which may be rotated manually so as to cause corresponding rotation of the screw-threaded shaft 17, thereby enabling the position of the lower guide plate 9 to be adjusted relatively to the base 8. The lower guide plate 9 also is equipped with an upstanding part 21 which journals a threaded shaft 22 received in a threaded opening in a part 23 formed at one side of the intermediate guide plate 11. A hand wheel 24 is mounted on the free end of the shaft 22 so as to facilitate turning of the shaft and adjustment of the intermediate guide plate 11 laterally relative to the lower guide plate 9. Similar apparatus comprising an upstanding part 25 on the intermediate guide plate 11, a screw threaded shaft 26 received in a threaded opening in the upper guide plate 15, and a handwheel 27 on the shaft 26, is provided for adjusting the upper guide plate 15 longitudinally relatively to the intermediate guide plate 11.

At the forward end of the frame work supporting means generally designated 28 is provided for supporting a workpiece in a position to be engaged by the grinding wheel 6. In the embodiment of the invention disclosed in Figures 1-3, the work supporting means comprises a work rest 29 including a blade 30 removably held in a slotted holder 31 by a set screw 32, the holder 31 being secured to the forward part of the intermediate guide plate 11 by suitable means such as bolts 33. The work supporting means also includes a pair of guide rollers 34 and 35 mounted on the intermediate guide plate 11 by means of journal bearings 36 and 37, brackets 38 and 39, and bolts 48 and 41, and about which more will be said subsequently. Also mounted on the forward end of the intermediate guide plate 11, but at a position spaced from the work supporting means 28, is a work receiving member or platform 42, the platform being supported at a height corresponding to the height of the work rest blade 30 by a bracket having a vertical leg 43 fixed to the under side of the platform 42 and having a slotted horizontal leg 44 adjustably secured to the guide plate 11 by a bolt 45.

The invention includes a work handling member 46 operable to receive a workpiece from the platform 42 and transfer it to the work supporting means 28 and assist the latter in supporting the workpiece in grinding position. As disclosed in Figures 1-3, the work handling member comprises a plurality of disc-like plates 47, 48 and 49 which are held in vertically spaced relation at their centers by hubs 5t) and 51 formed on the plates 48 and 49, respectively. Each of the plates is provided with a central opening for the reception of the enlarged upper end of a shaft 52 which is journalled for rotation in upper and lower bearings 53, 54, respectively, carried by a sleeve 55. The sleeve 55 extends through a circular opening A formed in the upper guide plate 15, through a forwardly and rearwardly extending slot B formed in the intermediate guide, plate 11, through a laterally extending slot C formed in the lower guide plate 9, through a forwardly and rearwardly extending slot D formed in the base 8, and through a forwardly and rearwardly extending slot E formed in the frame top 3 at its forward end. At its upper end the sleeve 55 is provided with a radially extending flange 56 which rests on the upper guide plate and is secured to the latter by means of screws 57, and at its lower end the sleeve is securedby s'c'rews'58 to a plate 59 whichis centrally bored as at; 60 to provide a passage through which the shaft 52' extends. At the periphery of 'the plate 59 is a plurality of threaded openings into each of which-is threaded the upper end of a rod 61, the intermediate portions of the latter passing through aligned'threaded openings formed inilpper and lower plates 62 and 63, respectively, which support a gear reduction housing or fluid coupling transmission device 64, and the lower. ends of the threaded tie rods .61 aretreceived in a plate65 to which is secured an electri motor, 66 having means'(not shown) to connectwit' to apower source. The positions of the several partsmay be adjusted and secured by-nuts 61a on the tierodsi61. .The motor armature 67 isconnected to the input shaft 68. of the transmission device 64 by a coupling 67-of knownconstruction and the output shaft '70 of thedevice 64 is connected to the shaft 52 by asimilar coupling 71.

I :In order toprovide a positive drive transmitting connection from the vshaft-52 to the work handling member 46, a metal bar 72 having a centrally located sleeve =73 is positionedon the upper end of the shaft 52- and is keyed to the latter by a pin 74 which passes through aligned openings formedin the sleeve 73 and in the shaft 52. The-:bar72 is keyed to the driving member '46 by'means ofpins 75 which pass through openings formed ineach of the three'disc-lik-e parts 47, 48 and 49 and which are held infixed relation with respect thereto by means of nuts 76 threaded onto the reduced threaded vends .of thezpins.

'The arrangement of the parts described thus far is such that the lower guide plate 9 may be adjustedtfon wardly or rearwardly relatively to the base 8 and the frame 3. so as to position the work supporting means 29 the desired distance from the grinding wheel '6. The

intermediate guide plate 11 then may be adjusted laterally relatively to the parts belowit so as to adjust the. axis of rotation of the member 46 relatively to the center line of the grinding wheel. Then the upper guide plate '15 may be forwardly or rearwardly adjustedrelatively to the parts below it so as to vary the distance from the peripheral edge of the member 46 to the work supporting means 29. ,It will be understood that the motor 66 audits associatedparts, including the shaft 52, will move whenever the upper guide plate is caused to move, whether movement of'the latter is caused by operation of its associated adjusting means 25, 26, 27 or by adjustment of one or both of the guide plates 9 and 11, but in either event such movement of the motor and parts will be permitted withoutinterference because of the provision of the slots B, C, D, and E in those parts of the apparatus located below the guide plate 15.

As is'best shown in'Figure 2,not'all of the diameters of-the plates forming the work handling member 46 are the same. The lowermost plate 49 is the largest in diameterandits periphery provides a ledge or part 77 projecting radially beyond the other twoplates so as to provide. a support for a workpiece in a manner yet to be described. Between the upper plate 47 and the lower P1316'49.18.I1d extending around the periphery of the intermediate plate 48 is a yieldable strip 78 of rubber or the like materiaL'the strip being doubled over at its center topresent'a smooth surface and having its upper edge received between the discs 47 and 48 and its lower edge rec'eivedbetween the dis-cs 48 and 49. The edges of the strip are removably clamped in position between the plates 47 and 49 by means of bolts 49a which pass through aligned openings in the discs and in the doubledover strip, the bolts having nuts 58a on their lower ends.

In assembledcondition, the strip 78 provides a .yield v able peripheral edge for the plate 48 which may be radially inwardly depressed for a purpose to be explained.

As is best shown in Figure 2, the upper disc-like plate 47 of the work handling member 46 is cut away at least at one and preferably at two places along its periphery as at 79, and the rubber-like strip 78 is similarly cutaway as at 80 so as to provide at leastone and preferably two diametrically opposed workpiece receiving openings 81 in the work handling member and which are rotatable with the member 46 from a work loading station opposite the receiving platform 42 to a work grinding station opposite the grinding wheel 6 and return. The lower disc-like plate 49 also is provided with a number of Cut outs or interruptions 82 corresponding to the number of work receiving openings 81, but in each instance the interruption 82 is angularly spaced ahead of the adjacent opening 81 in the direction of rotation of the member 46.

Means is provided for loading the work handling member automatic-ally and in the disclosed embodiment comprises a lever arm 83, having a cam surface 84 thereon fixed to the lower end of a collar 85 which is mounted on a post86, the latter being secured to the upper guide plate 15. The arm 83 extends towards the rear of the apparatus and normally is biased by a spring 87 towards a position at one side of the apparatus so as to locate the cam surface 84 in the path of a cam 88 fixed to the underside of the lowermost plate 49 of the work handling member 46. Also'secured to the collar 85, but at the upper end thereof, is. an arm 89 which lies atop the load ing platform 42vand has its forward end curved as at 90 so as partially to embrace a workpiece located on the platform in a position corresponding to the chain line showing designated W-1 in Figure 2.

In the operation ofthe apparatus, the work supporting means 28 and the work handling member 46 may be adjusted relatively to the grinding wheel in the manner previously described so as to condition the apparatus for use with an annular or disc-like casting or workpiece W such as is disclosed in the drawings. The grinding wheel 6 will be caused to revolve in the direction of the arrow a (Figure 1) and the motor 66 will be started so as to rotate the work handling member in the direction of the arrow b in Figure 2. A workpiece W will be placed on the loading platform 42 at the position marked W-l and as one orthe other ofthe work receiving openings 81 comes opposite'the platform 42, the corresponding cam 88 will engage the carnsurface 84 on the lever arm 83 causingboth of' the lever arms 83 and 90 to be rocked clockwise, as is viewed in Figure 2. Clockwise rocking of the-lever arm 90 will push the workpiece W from the W1 position towards the work handling member 46, i. e., to the position shown by chain lines and markedW-2, and the movements of the parts will be so timed that the workpiece W will be pushed into one of the openings 81 whereupon continued rotation of the member '46 will cause'that part of the yieldable strip 78 angularly rearwardly of and adjacent to the opening 81 to bear against the periphery of the workpiece W and propel it off the platform 42. As the work handling member and the workpiece move clockwise, as viewed in Figure '2, the edge of the workpiece will engage the guide roller 34 and the yieldable strip 78 will be radially depressed, but since the strip 78 is formed of rubber or similar highfriction material, the workpiece will be rotated about the guide roller 34 until it is in a position to be moved forwardly under the force of the expansion of the depressed yieldable strip'78, atwhich time it will occupy the space between the rollers 34 and 35 in the position shown in full lines in Figure 2 and will have its forward peripheral edge supported by the work rest 30. Throughout themovement of the work receiving opening 81 from the loading station to the grinding station,.the workpiece W also will be supportedby the'ledge'or part "77 of the member 46 and when the workpiece is in the grinding position the part 77 will assist thework supporting means 7 29 in supporting the workpiece.

to the grinding wheel, the former should be so spaced from the latter that the peripheral edge of t he strip 78 v will remain in contact with the workpiece. This assures that rotation of the work handlingmember will cause the workpiece to be rotated about'its own axis so as to present its entire peripheral edge to the wheel and have all of the snags or projections 91 (Figure 3) ground off. When a snag is presented to the grinder, the workpiece may be thrust rearwardly as will be permitted by the yieldability of the strip 78 so as not to require a complete grinding otf of the snag in one pass. This arrangement promotes longer life, for the grinding wheel and the grinding of the workpiece is not adversely affected inasmuch as theworkpiece will be rotated a number of revolutions about its own axis before it is discharged so as to assure that each snag will pass the grinding wheel a number of times.

81 approaches or is at the loading station, the notch 82 just ahead of that opening will pass under a workpiece at the grinding station so as to remove the support for the rear edge of the workpiece. At this time the workpiece will up andslide 011 the work rest 30 and will fall away by gravity through an opening F formed in the forward parts of the lower and intermediate guide plates 9 and 11 and be received in a chute or the like (not shown). Subsequent workpieces will be handled in the manner just described.

Eventually, the grinding wheel will wear to such an extent that it no longer will ,grind 0E snags cleanly. At this point an adjustment may be made of either or both of the guide plates 9 and 15 to compensate for the Wear of the grindingwheel. If the center of the work handling member remains on the center line of the grinding wheel so that the workpiece engages the grinding wheel tangentially at the center of the latter, the grinding wheel soon would be worn to-a concave shape. To prevent this from occurring, the work handling and supporting members may be adjusted laterally by operation of the adjusting screw 22 to as to position the work handling member and the work supporting means 29 to one side or the other of the center line of the grinder.

line of the grinding wheel 6, so as to enable more even wear of the latter to take place, but will not otherwise change the operation of the apparatus.

In Figure 4 there is shown an alternate arrangement which may be used when the center lines of the work handling member and the grinding wheel do not coincide. In this arrangement a loading platform 42a is of suflicient length to extend completely across the grinding wheel 6 so as to provide means for supporting the workpiece W at the grinding station. The work handling member 46a may consist of a single disc-like plate 49a having one or more work receiving openings 81a 7 therein, and a corresponding number of work discharging openings or recesses 82a, the receiving and discharging openings being alternately located about the periphery of the plate 49a. In the operation of the embodiment shown in Figure 4, a workpiece will be placed on the platform 42a in a position to be engaged by loading means such as the arm 89, previously referred to, when the work receiving opening 81a is opposite the loading station, the loading arm acting to propel the workpiece into the opening 81a in the manner previously described.

Continued rotation of the member 46a in the directionindicated by the arrow d will move the workpiece to the This adjust-. ment will locate the workpiece laterally .of the center grinding position; shown in Figured. The position of the member 46a have been so adjusted relatively to, the grinding wheel 6 that there is not suflicient cleargrinding wheel to allow the workpiece to pass the grinding wheel. Therefore, the part 77a will assist the platform in supporting the workpiece by holding the latter against the grinding wheel and rotating it about its own axis during the return movement of the opening 81a until such time as the interruption 82a moves opposite the grinding station. The depth and configuration of the interruption 82a are such that the ground workpiece will be received therein and carried past the grinding wheel to a position where the workpiece may drop oh? the platform 42a. If desired the member 46a may be provided with a rubber or the like part, similar to the strip 78, to provide a high-friction edge surface for engagement with the workpiece.

In'both forms of the invention, the construction and arrangement of the parts forming the work handling member are such that any one of a plurality of varying size members may be used and the substitution of one member-for another may be accomplished quickly and simply. Referring to Figures 1-3, the disclosed work handling member 46 may be replaced by another having more ,or less work receiving and discharging openings by removing the pin 74 and lifting the member 46 oif the shaft 52. Then the integral sleeve 74 and the bar 72 may be slipped .05 the pins 75'and placed on similar pins of a similar work handling member which then may be mounted on the shaft 52. The interchangeability of parts enables the apparatus to be used for grinding articles of greatly varying size.

The disclosed apparatus is representative of preferred forms of the invention, but is intended as illustrative rather than definitive of the invention. The invention is defined in the claims.

vWe claim:

1. Apparatus for use in conjunction with a rotary grinding wheel comprising a workpiece handling member having a work receiving opening movable in a substantially horizontal plane from a work loading station to a work grinding station and return and having a work supporting part for supporting a workpiece throughout the movement of said work receiving opening from said work loading station to said work grinding station; means for supporting a workpiece at the grinding station, said work supporting part assisting said work supporting means in supporting a workpiece at said grinding station, said work supporting part being interrupted for a portion of its length so that during a portion of the return movement of said work receiving opening a workpiece at said grinding station is unsupported by said part and may be removed from said grinding station; and means for moving said member.

2. The construction set forth in claim 1 in which said member includes yieldable means carried by said member for ejecting a workpiece from said work receiving openat said grinding station and positioned to engage a workpiece during the return movement of said work receiving opening so as yieldably to hold the workpiece in grinding position at said grinding station.

3. Apparatus for use in conjunction with a rotary grinding wheel comprising a rotatable workpiece handling member having a work receiving opening rotatable in a ing tion to.a work grinding station and return and having a radially projecting part to provide support for a workpiece throughout the rotation of said work receiving opening from said work loading station to said work grinding station; means for supporting a workpiece at said grinding station, said part assisting said work supporting means in supporting a workpiece at said grinding station but being interrupted for a portion of its length so that durfor ejecting a-workpiece from saidwork'receiving opening at said grinding stationand positioned to engage a workpiece supported at the grinding-stationduring return movement of saidmember so as yieldably to"hold"-a'-woi'k-- piece in grinding position at saidgrinding station.

"5. Apparatus for-use in conjunction with a-grin'ding wheel'comprising a frame; aworkpiece handling-member having a work receiving opening; -'means 'mounting said rncmber'on' saidframefor movement of said'opening-in a substantiallyhorizontal planefroma-workpiece receiving station to-a workpiece grinding station'a'ndreturn, said member having a-workipiece-supporting'partfor supporting a workpiece throughout the movement df'saidopening from said receiving-station-to said grinding station; means for supporting a workpiece atsaid grinding station, said workpiece supporting part assisting-said work supportingmeans in supporting a workpiece at said grinding station'but'being interrupted for-aportion of its'length so that during a portion of'the return movement of said work-receiving opening 'a workpiece atsaid grinding station is unsupported by said part and 'may beremovedfrom said grinding station; and means carried bysaid frame'for moving said member.

6. The construction set forth-'in'claimiinwhich said member includes yieldable means carried by saidmember for ejecting a workpiece fromsaid woi-kreceivingopening at said grinding station and positionedito engage a workpiece supported at the grinding station :during return movement of said work receiving opening so-as yieldably to hold a workpiece in grinding position -at-said grinding station.

7. Apparatus for use in conjunction with a grinding wheel comprising a frame; a platform; means mounting said platform on said frame; work supporting means; means mounting said work supporting means on said frame at a position spaced from said platform; a work handling member having a workpiece receiving opening therein; means mounting said member on said frame for movement of said opening in a substantially horizontal plane from a work loading station adjacent to said platform to a work grinding station adjacent to said work supporting means and return, said member including a workpiece supporting part for supporting a workpiece throughout the movement of said opening from said loading station to said grinding station and for assisting said work supporting means in supporting a workpiece at said grinding station during at least a portion of the return movement of said opening, said workpiece supporting part being interrupted for a portion of its length so that during a portion of the return movement of said opening a workpiece at the grinding station is unsupported by said part and may be removed from the grinding station; and means for moving said work handling member.

8. The construction set forth in claim 7 including means for transferring a workpiece from said platform to said work handling member when said opening is adjacent to said platform.

9. The construction set forth in claim 8 in which said transferring means comprises arm means having a cam surface thereon; means mounting said arm means on said frame for swinging movement thereof across said platform, and cam means carried by said work handling member in a position to engage said cam surface and cause said arm means to swing.

'10. The construction set forth in claim 7 in which said member includes yieldable means carried by said member for ejecting 'a workpiece from said work receiving opening at said grinding station and positioned to engage .a workpiece supported ..at the grinding. station '8 during return-movement of said member so as yieldably to hold a workpiece ingrinding-position at saidgrinding station.

1'1.'l1"he constructionset forth in claim 7 including means for-adjustingthe positions-of said work supporting-means and saidwork handling member relatively to said frame and to each other.

'IZuGrindingapparatus comprising a frame; a grinding-wheeh-means mounting said grinding wheelon'said frame; -'a platform means mounting said platform on said frame; work supporting 'means; means mounting said'work supporting means on-said frame at a position'space'd from said platform and adjacent to said grinding Wheel; a work handling member having a workpiece receiving opening therein; means mounting said member on said framefor movement of said opening in-a substantially horizontal plane from awork loading station adjacent'to said platform to a work grinding station adjacent to saidwork supporting means and return, said member including a workpiece supporting part for supporting a workpiece throughout the movement of said 'opening'from said loading station to said grinding station :a'n'ti for assisting said work supporting means in supportinga workpieceat said grinding station during at least a portion of the return movement of said opening, said workpiece supporting part being interrupted for a' portion of'itSLIengthsQ that during a portion of the return movement of said opening a workpiece ,at the {station is .unsupportefd'by said part and may be removed from the grinding .stationpand fmeansjfor movingsa'id work handling member.

"13."I he construction set forth in claim 12jincluding means fontrans'ferring a workpiece 'from said. platform .to said workhandling member whensai'd opening is adjacent to 'sa'idplafform.

14. The construction set forth in claim 13 in which said transferring means comprises armimeanshaving -a cam surface thereon; means mounting said arm means on said fraiue'for swinging movement thereof acrossfsaid platform, and cam means carried by-said workhandling member'in a position to engage said cam surfacevand cause said arm'means to swing.

15. The construction set forth in claim 12 in which said member includes yieidaole means carried by saidmember for ejecting a workpiece from said work receiving opening vat said grinding station and positioned to engage a workpiece supported at the grinding station during return movement of said member so as yieldably to hold a workpiece in grinding position at said grinding station.

16. The construction set forth in claim 12 including means for adjusting the positions of said work supporting means and said work handling member relatively to said frame and to each other.

17. Apparatus for use in conjunction with a rotary grinding wheel comprising a frame; a workpiece handling member on said frame having a work receiving opening movable in a substantially horizontal plane from. a work loading station to a.work grinding station and return and being capable of carrying a workpiece from said loading station to said grinding station; means on said frame for supporting a workpiece at said grinding station, said member havinga part for assisting said supporting means in supporting a workpiece at said grinding station, said partbeing interrupted for a portion of its length so that during a portion of the return movement of saidwork receiving opening a workpiece at said grinding station is unsupported by said part and may be removed from said grinding station; and means connected to said member for -mov-ing-the latter.

18. Apparatus for ,use in conjunction withaa grinding wheel comprising a frame; a -:w.ork handling member having ;a work receiving opening 'thereinpmeansqnounting said member on said frameformovement ofv saidwork receiving-opening from.arworkdoadingzstation; tosa :work

grinding station and return; a platform mounted on said frame and extending from said loading station to said grinding station for supporting a workpiece at each station, said member having a part for assisting said platform in supporting a workpiece at said grinding station, said part being recessed for a portion of its length so that during a portion of the return movement of said work receiving opening said recess receives a workpiece at the grinding station and removes it therefrom; and means connected to said member for moving the latter.

References Cited in the file of this patent UNITED STATES PATENTS

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