US2857612A

US2857612A - Oscillating doctor knife bar and cutting angle adjustment

Info

Publication number: US2857612A
Application number: US493327A
Authority: US
Inventors: Albert M Fischer
Original assignee: DAVENPORT MACHINE AND FOUNDRY
Current assignee: DAVENPORT MACHINE AND FOUNDRY; DAVENPORT MACHINE AND FOUNDRY Co
Priority date: 1955-03-10
Filing date: 1955-03-10
Publication date: 1958-10-28
Anticipated expiration: 1975-10-28

Description

oct 28, 1958 A. M. FISCHER 2,857,612

OSCILLATING DOCTOR KNIFE BAR AND CUTTING ANGLE: AnJusTlmzm Filed March 10, 1955 5 Sheets-Sheet 1 e W mw f ma U Y Maz/@ ATTORNEY Oct. 28, 1958 A. M. FISCHER 2,857,512

' OSCILLATING DOCTOR KNIFE BAR AND CUTTING ANGLE ADJUSTMENT Filed March l0, 1955 5 Sheets-Sheet 2 INVENToR 2) wer/V, /avie BY MM; f m

ATTO R N EY A. M. FISCHER oscn. TING nocToR KNIFE BAR AND CUTTING ANGLE ADJUSTMENT Oct. 28, 1958 5 sheets-sheet s Filed March 10, 1955 -mlhmw Oct. 28, 1958 A. M. FISCHER 2,857,612

OSCILLATING DOCTOR KNIFE BAR AND CUTTING ANGLE ADJUSTMENT A Filed March l0, 1955 5 Sheets-Sheet 4 NVENTOR 4455er/Z /scf/fe ATTO R N EY Oct. 28, 1958 A. M. FISCHER 2,857,612

oscILLATING DocToR KNIFE BAR AND CUTTING ANGLE ADJUSTMENT Filed March l0, 1955 5 Sheets-Sheet 5 l INVENTOR ATTO R N EY United States Patent 4 OSCILLATING DOCTOR KNIFE BAR AND CUTTING ANGLE ADUSTMENT Albert M. Fischer, Dowagiac, Mich., assignor to Davenport Machine and Foundry Company, Davenport, Iowa, a corporation of Iowa Application March 10, 195s, semi No. 493,327

4'c1aims. (ci. 15-2565) The present invention relates to doctor knives for moving surfaces and is more particularly directed to an apparatus for adjusting the cutting angle and depth of 'cut of oscillating doctor knives, and to a means for the simple accomplishment of coordinated oscillation while the surface served is in motion.

The art has long recognized that present day doctorknife assemblies are inecient in their operation when the material per se is changed from those conditions for which the cutting angle of the knife assembly is initially set or designed to operate under. In such instances where the optimum cutting angle `must be determined by trial and error the dryer apparatus, for example, must be shut down while the cutting angle is being adjusted. Further, when the knife blade becomes dull most known assemblies require the lengthy process of sharpening or honing or the replacement of the dull blade. The cutting angle available for a single assembly is limited by the inherent design features of the particular doctor knife assembly. Therefore, as different materials are fed, these being dictated by production pressures, the eiciency of the doctor knife may be reduced because variations in cutting angle are not readily available. Further, when the blade becomes worn, the thermal eihciency of the dryer is reduced due to incomplete removal of material from the drum and in instances of maladjustment scoring of the surfaces served frequently occurs. Present day known designs do not provide a structure capable of prolonging the life of a blade by changing its cutting angle during operation.

In order to reduce wear to a blade or damage to a surface due to uneven or excess pressures, present day construction of doctor knife apparatus generally has provided for an oscillating movement of the entire doctor knife assembly transverse the face of the drum paralleling the axis of the drum Where, for example, dryer drum surfaces are being served. That is to say in some designs the knife, the knife bar, the knife bar support, the .support axles, the bearings, and even the bearing supports have been designed to oscillate with the knife. Such a system has a relatively large power requirement. Minimization of these relatively large power requirements of drum and oscillating apparatus has long been sought. Further, the

equipment and mechanism for accomplishing such movement is expensive to produce, install, maintain and repair. In such oscillating systems where the entire assembly oscillates the oscillation frequently damages the alignment of the equipment with which it is associated. No known doctor knives, either oscillating or stationary, have been designed to change the cutting angle or angle of attack of the knife blade to a served surface, for example, a rotating drum, during continuous operation. Some adjustment of cutting or attack angle is required in all doctor knives, whether they serve a planal or cylindrical surface. In the previously known doctor knives, the equipment must be stopped and the operation shut down in order to change the cutting angle of the blade. Since -knife a reduction of adjustments cannot be made during operation the thermal efliciency of the dryer surface is impaired and damage to the surface served often results from unavoidable changes during service. It will be seen that the novel construction hereinafter described avoids these numerous diculties encountered by presently known doctoring knives.

Further deficiencies are found in, for example, double 'drum dryers of the present day construction, wherein end dams are utilized to maintain the material within the confines of the working surface. These dams are maintained in position by end dam pressure spindles. The pressure` of the spindles tends to force the dryer frames out of alignment and cause damage to bearings, knife bar bearings, et cetera. Spacers and bracing structures are normally provided below the drum to prevent misalignment. These,

however, are not completely satisfactory. No known doc.

tor knife assemblies assist in providing bolstering support. Therefore, an object of the present invention is to pro vide an oscillating doctor knife assembly which will oscillate only the knife bar with the knife blade.

continuous oscillation even during the changeV in cutting angles. l

A further object of the present invention is to provide an oscillating doctor knife which is adjustable in its angle of attack without interruption of continuous operation.

A still further object of the present invention is to pro-A vide an economically fabricated doctor knife constructiom,

adaptable to a variety of planal or cylindrical surfaces and materials, which is easily maintained and repaireds, A further object is to provide a doctor knife construc-y tion having as a result of reduced pressure of the doctor power requirement to the moving surfaces served.

Another object of the present invention is to provide a.` knife bar assembly which will serve as a tie rod and assistY in counteracting the outward thrust and stresses ofthe end dam pressure lspindles in, for example, a single` or multiple drum dryer.

Another object is to provide a knife bar assembly which assures thermal efficiency of the surface served.

A still further object of the present invention is to pro-` vide an oscillating doctor knife which can be adjusted in cutting angle approach to present at all times a sharp, well-defined blade point to the served surface and thus prolo-ng the serviceabilityI of the blade, during continuous operation of the knife assembly.

These and other objects will become apparentV to those skilled in the art as theV description of the present inven tion proceeds.

In the drawings:

Figure 1 is a front elevation of the oscillating knife'bar with cutting angle adjustment and mounted over a served surface on a frame shown cutaway.

Figure 2 is a cross section view taken on line II-II of Figure 1.

Figure 3 is a cross section view taken on line III--III of Figure 1.

Figure 4 is a cross section view taken on line `Iv-Iv et Figure 1.

Figure 5 is a cut away perspective detail showing theV mechanism permitting oscillation to proceed while-ad? justments of the cutting -angle areV being made. Q

Figure 6 is a top plan view of double ydrtuudryei's andj a illustrating a` plural installation of doctor knife units in accord with the present invention showing the knife cases removed and indicating the ltie rod function of the doctor knifeiassembly- :Figure ,1-7 liis f.; a. schematic vrdiagram showing. a .blade @in contact withsa drum f surface.

v A4 E-igiire. is a schematicI diagram showing a worn blade. 2Eigure--9 is.a schematicvdiagramshowing an adjusted worn blade.

. Figure 1.0j is .a schematic `diagram `demonstrating :the compound .adjustment possible in thestructure herein described` and showingthe .independent movements .that are coordinated to, givefvariations in -the angle of blade contact .,witlLa surface.V

,Eigu-re l1'` is,a,full. section ,elevation View showing the universal connection shownin, Figure4.

GENERAL 'DESCRIPTION 'TVI-hepresent invention provides a:doctor knife apparatus having concentric shafting,.and anV outer cylindrical case forminga 4knifeabar. .The knifebar or outer cylindrical case Vis displaced from concentricity ,with .the concentric shfting by a pairof eccentrics mounted on van outer or main shaft. The main yshaft has an oscillating drive shaft concentrically mounted within oneendvthereof toprovide oscillating motion to the outer eccentrically rotatable mounted cylindrical case or knife bar. The linkage between `the-drive shaft and case through the` main shaft isaccongplished by a'drive pin. The cylindrical., case or knifejbarcarries a knife clamping plate and a doctor blade. Means associated with the outer eccentrically rotatably mounted `cylindrical..case or knife bar are provided to rotatel the blade carrying case about the eccentrics. Additional means are provided to rotate the .main shaft and associated eccentrics independently of any rotation in the eccentrically vmounted cylindrical case.

'In the preferredembodiment of the present invention, when; for example,V the surface served is a rotating drum, adoctor knife assembly is provided offset from the drum faceland extending longitudinally across the convex face of the drum parallel to the axis of rotation of the drum. Thedoctor knife assembly or apparatus comprises a pair fdbearing mounts or bearing supports mounted on, or attached to, the housing or dryer frame; bearings mounted in lthe bearing mounts; a main shaft rotatably mounted Within'the bearings and extendingacross the face of the drum parallel with the axis of rotation of the drum,at least aone end--of the main shaft being tubular and concentrically-bored toreceive and journal-an oscillating drive shaft; and the main shaft being longitudinally slotted near-theainner end of the concentric longitudinal bore to provide a pair ofguideways through the opposite walls of thexmain'shaft; a Vdrive pin penetrating said drive shaft projecting outwardly therefrom through the slots provided therein andl beyond the outer circumference of the-main shaft; agrooved receiving ring fixed against longitudinal movement'in :the cylindrical case being in clearance rela tionship around the main shaft and having the drive pin ofathe id rive; shaft inserted in :the groove .of theA ringfor causing `axialxmovement-of the knife casein coordination with the oscillation of the drive shaft; anda pair Aof eccentrics keyed on the main shaft near: eacheen'd `rthereof forfmovementfwith the main. shaft between the bearings -of thefmain shaftaand; outboard of the longitudinalslotshin the main shaft. Concentrically mounted over the keyed eccentricsA in" rotatable relation thereto is a cylindricalcase or knife bar tube having a tangential external ledge 'for attachment ofta-.knifel clamp .plate and a 'doctorknife blade. Hubbed arms are adjustably secured to the cylindricalicasezor sleeveat eitherk end thereof, the armsubeing provided with pivotal levers depending from the .hubsat either .end i of the doctor knifel assembly. `Shoulders integral .with-.the .cylindrical case :inboard of.: saidhubs. and split rings .outboardof Asaid; hubsare,l providedtofmaintaimsaidhubfand associated arms ill/aligned axial relation with said eccentrically mounted sleeve or knife bar. Independently adjustable means are provided on the end of each of the depending arms for adjustably rotating the lever arms to cause resulting rotation of the cylindrical case or knife bar about the axis of the eccentrics.

. A bearing housing at one end gof the main shaft is pro- Y vided with a worm and Worm gear. The worm gear is keyed to the mainV shaft. A worm is provided With'a hand SPECIFIC DESCRIPTION Referring with more particularity to the drawings a moving surface shown as a rotating drum drycrllfris shown in Figure l having a drum 12 rotatable aboutan axis. In Figure 6 a double drum dryer 13 is illustrated. The axles 14 ofthe drums 15 are mounted,.in bearings` within a frame 16,having end ldams.17 and 18. The end i dams 17 and 18 laterally confine the material fedbetween the drums15 (Figure 6). VMounted on the frame 16 are a pair of bearing supports 19 and 20, respectively, each provided withbearing receiving means.l i bearing support 19 and 2i) are bearings 22 and 23. One

of saidjbearing V supports .20 comprises a combination` bearing and Wormgear housing 24. The purposelof the worm gear.` drive will be ,morefully understood as- 1the l description proceeds.

AA main shaft .25 is rotatably mounted in the bearings.

19 and 20. On one end of the main'shaftV 25 and the worm gear housing24 is keyed a worm 4gear26.V Each end of the main shaft 25 is secured outboard ,of the bearing supports 19 and 20 thus preventingtheshaft from shifting longitudinally. Various securingrmeans Amaybe employedythe simplest being split rings 27 and-28 re tained "in suitable grooves in the main 'shaft 25. 'lhe wo-rmV gear end ofthe main shaft 25 is tubular, beingprovided with a concentricbore 29 extending longitudinallyf` into 7the A.main shaft'25. Near' the extreme inner. Vendof.

the bore 29, the main'shaftZS is provided Witha pair of longitudinal slots 3i) and 31 through the Wall ofthe` mainfshaft 25 communicating the main shaft outer cir,- cumference with the concentric bore 29.

Concentrically mountedv within the bore 29 is an oscillating drive shaft 32. The drive shaft 32 is reciprocatingly-ournaled in the bore 29. At the inner end33 of .the .drive-shaft 32' is a drive'pin34 secured through the drive shaft 32. The pin34 extends radially-outward from the drive shaft V32 into and through the elongate slots 30 and 31 through the wall` of the'main shaft 25. The drive pin 34, attached to the drive shaft 32; can thus float-reciprocatingly in theslots Y3i) and 31. A

grooved receiving ring 35 receives the extensions of the y pin 34 where it extends beyond the outer circumference of the main shaft25. The drive pin 34 rides in close tolerance inthe groove 36 of the receiving ring 35- and the receiving ring 35 responds toany reciprocatory'movement of the drive shaft 372. of the. grooved receiver ring 35,- the -groove36 is defined by the internal shoulder of the ring 35 and an abutting' annulus 35a having any inside diameter smaller than the diameter of groove 36 so as to retain the drive pin 34in the groove 36. The receiving ring 35 is a hollow cylinder and is in clearance relationship with the main shaft 25. The importance of this receiving ring 35 will 1become increasingly apparent as the description proceeds;

.A pair of-

eccentrics

37 and 38 are secured as by afkey 37a to thel main shaft 25 inboard of the end dams17 '4 Within earch` In the preferred construction and 18 and outwardly of the slots 30 and 31 in the main shaft 25. The

eccentrics

37 and 38 are in fact cylinders having anoffset axis from the axis of the drive shaft 32.

A cylindrical case'or knife bar sleeve 39 is concentrically mounted on the

eccentrics

37 and 38 for rotatable movement thereover and in sliding reciprocating motion therealong. The cylindrical case 39 has a tangential flanged ledge 40 for mounting a doctor knife blade 41 and a doctor clamp plate 42 thereon. The blade 41 is preferably secured by the clamp plate 42 and the thumb screws 43 are provided for alignment. Bolts 44 through the ange 40 and the blade 41 draw the blade 41 securely against a machined step 45 in the anged ledge or shoe 40. Thus, the cylindrical case or sleeve 39 is rotatable on the

eccentrics

37 and 38 and carries a blade mounting ledge 40 to which thte blade 41 is attached. On the inside of the cylindrical case 39 a shoulder 46 is provided against which the receiver ring 35 is positioned. A spaced annular groove 47 is provided in the inside of the cylindrical case 39 for accommodating a snapring 48 against which the other side of the receiver ring 35 abuts. Thus, the cylindrical case 39 may be rotated about the receiver ring 35, but the case 39 is moved longitudinally as the receiver ring 35 is oscillated by the drive pin 34 in response to longitudinal movement of the drive shaft 25.

While the receiver ring 35 has been described as rotatable within the shoulder 46 and the snap-ring 48, it may also be held tightly therebetween and prevented from movement independent thereof. The annular receiving ring groove 36 thus becomes the surface within which the pin 34 rotates. The -reciprocation of the knife bar or case 39 still is controlled by the reciprocation of the pin 34 with the drive shaft 32.

At each end of the cylindrical case 39 are collar-like brackets or hubs 49 and 50 rotatably and adjustably Vattached to the cylindrical case or knife bar 39. The adjustable attachment is accomplished by means of set pins 51 and 52, each having an eye 53 and 54 at their outer extremity. "The brackets or hubs 49 and 50 accommodate the set pins 51 and 52 which lock the brackets 49 and 50 in a desired position-on the ends of the cylindrical case 39. Clearance is provided between the brackets 49 and 50 and the bearing supports 19 and 20 so that as the cylindrical case or knife bar 39 is oscillated the moving brackets 49 and 50 do not contact any part of the frame 16 or the bearing supports 19 and 20. Lateral movement of the hubs 49 and 50 along the cylindrical case 39 is restricted by annular shoulders 49a and 50a on the case 39 and split rings 55 and 56 seated in annular grooves 57 and 58 in the surface of the case 39 near the ends of the case 39.

Arms

59 and 60 in the nature of levers depend from the brackets or hubs 49 and 50. Knife pressure adjusting means 61 and 62 mechanically and linkedly extend to adjustably engage the

lever arms

59 and 60. The movement of the adjusting screws 61 and 62 causes arcuate movement of the

levers

59 and 60 and corresponding rotational movement of the case 39.V The

arms

59 and 60, in the nature of levers, are pivotal where they attach to the brackets 49 and 50. By thus pivoting the

arms

59 and 60 rockably from the brackets 49 and 50, rotational adjustment of the case 39 is provided and the pivoted

arms

59 and 60 can clear any associated apparatus in the manner of a pivotal link. The knife pressure adjusting screws 61 and 62 are actuated by handwheels 63 and 64 rotatable in fixedly mounted blocks 63a and 64a, correspondingly left and right as shown in Figure 4.

Internally threaded actuating members 65 and 66 are threaded onto the knife pressure adjusting screws 61 and 62, and are pivotally connected to the depending ends of the arms v59 and 60 through unique pivotal blocks 67 and 68, respectively. Then blocks 67 and 68 are pivotally mounted at one end to the

arms

59 and 60 and rotatably connected thereto in -the manner of a universal.

The rotatable connector is further right angularly and rotationally mounted in the pivot blocks 67 and 68 as clearly shown in Figure l. The mechanism shown in Figure 4 provides a suitable steady rest or guide against any objectionable rotational movement. Element 65 is shown as an internally threaded sleeve having an outer sleeve 65a slidably mounted thereover said sleeve 65a having a cylindrical projection 65b extending right angularly .therefrom journaling through arm 67. This novel arrangement provides a universal action maintaining each main part in proper alignment yet permitting angular movement of the parts. Thus arm 59 can swing in an arc in response to lineal movement of block 65 along screen 61. The universal vcoupling provides in accordance with the mechanical requirements of the respective member the movement of internally threaded members 67 and 68 along screw 61 and 62 permitting a swinging or arcing movement of

arms

59 and 60 without binding members 67 and 68 to screws 61 and 62 respectively.

Assuming the set pins 51 and 52 to be locked to the case 39, rotation of the handwheels 63 and 64 causes corresponding lateral movement in the actuating members 65 and 66 and through the linkage with the universal joint arcuate movement of the

arms

59 and 60. The

arms

59 and 60 are moved causing rotation of the brackets 49 and 50 land subsequent rotation of the case 39. The bearing housing 20 comprising one of the bearing supports has therein a worm 69. The worm 69 is in operable engagement with the worm gear 26. The worm gear 26 is keyed to the main shaft 25. A worm handwheel 71 is operably attached to the shaft of worm 69.

The housing 24 of the worm 69 and associated bearingsy 72, as necessary, are provided in the bearing support 24. As the worm 69 is rotated the worm gear 26 is actuated, thus rotating the main shaft 25 and the

eccentrics

37 and 38 mounted thereon.

A reciprocating drive device 73 is provided outboard of the bearing support 20 and is directly connected to the drive shaft 32. The reciprocating device 73 is aligned with the drive shaft 32. While the drive device 73 illustrated, consisting of a fluid operated cylinder, represents one satisfactory means of accomplishing positive reciprocation of the drive shaft 32, other equivalent mechanical expedients wellknown in the art are intended to be descriptively included such as rack and pinion, hydraulic and pneumatic double acting pistons, and various cam, screw gearing and eccentric arrangements and reversible direct electric drives. In cooperation with the reciproeating drivedevice 73, timing means are intended to be included for varying the frequency of oscillation as desired. The hydraulic lines 77 and 78 supplying power to the drive device 73 are indicated in Figure l.

Operation In the operation of the oscillating knife bar and cutting angle adjustment of the present invention, the worm handwheel 71 is rotated to adjust the cutting angle of the doctor knife blade 41 to the desired angle for the particular material to be removed from the cylindrical or planal served surface 74. The worm handwheel 71 operates the Worm gear 26 which is keyed or otherwise secured to the main shaft 25, thus rotating the main shaft 25. This rotation of the main shaft 25 will vcause corresponding rotation of the

keyed eccentrics

37 and 38. Rotation of the

eccentrics

37 and 38 on the axis of the main shaft 25 will change the angular relation between the main shaft 25 and the cylindrical case 39 carrying the knife blade 41. The angular relationship as between blade 41 Vand served surface 74 will be altered correspondingly but the action of the

eccentrics

37 and 38 is predominantly cam-like in nature serving to back ot from Aor approach the blade 41 to the surface 74 served. The action of eccentrics either backs off the blade 41 in relation to the surface served 74 or moves the blade 41 into closer relationship with the served surface 74. Position 7' 'BfinlFigure 10 demonstratesgthis, adjustment .on au exaggerated' scale.

The set pin 51 or` S2 in one of the brackets '49-or 50 is withdrawn. `The other set pin 51 or 52 is left in vits locked'position in the cylindrical case 39 andthrough the'bracket-49 or 50. vThe screw -61 or62 engaging the arm 59 orl 60 is rotatedby means of handwheel V63 or 64 soas torotatethe cylindrical' case 39 by arcuately movingfthe-bracket49'or 50 which-is still locked Ainto engagementwwithxthe case 39. lThis movement pivots the case 39` and-'the associated-knife blade 41- into or out of engagement-with the cylindrical or planal working surface andtthus changes the attack angle of the' blade V41 when coordinatedA withA the-action ofthe eccentrics 37 and38. When 1drumdryers-15 are servedy'this compound adjustment'gresultsinia variety of cutting angles being made available at -the'drumsurface. 'T he pressure of the blade 41 on rthe 4surface is controlled `primarily by 'the rotation of the case"39^and theseadjustments are made without interruption'of movementin the drum dryers or `the reciprocation-of 'the blade :41. The other handwheel 63 or 64 is then Vrotated in the same direction until 'its set pin`-51 or '52 which was withdrawn drops Vinto a' hole 75 or76 provided inthe case or knife bar'39. The set pin'holes'75 and"76-are `in alignment to thatthe motion in both screws is thus coordinated. From this position the handwheels V63 and-64 krotating `the case`39are Vused to regulate the pressure forcingftheyknife blade 41 vagainst the drum surface'74.

The reciprocating drive device 73 is energized causing reciprocation of Ythedrive shaft 32. .Thefrequencyeof oscillation is adjusted as 'desired Vby timing means not illustrated. This recipro-cationof the Adrive shaft32 and its associated drive j-pin 34 causes corresponding longitudinaland axially oscillatory movement ofthe' cylindrical case 39 and its `associated blade 41. This'reciprocating-linkage is acomplished through the drive pin 34 reciprocating inthe slots `30 and 311through'themain shaft ry andthe connection, ofV the drive pin 34 in `the groove 36 of", the longitudinally xed receiving ring35. The Adrum 12y (where the surface doctored is cylindrical) is nowgrotated and a^slurry is fed, forrexample, tothe dryer.

If it isidesired to change the cuttingl angle of the blade 41 during operation, it is necessaryto operate the handwheel'71 to cause eccentric blade displacement and coustant surface contact while simultaneously operating handwheels`63 and 64 to revolve lthe case 39 and associated blade 41 ongthel eccentrics '37 and 38, as indi-cated, to maintaincontact pressure. It willbe understood that though manualmeans for this adjustment have been speficially described automatic adjustment `as by springs, hydraulic, or electrical actuationtnay be inserted without a departure from my structure.

lnFigures'v7,.8, 9, and l0 the eect of the blade adjusting structure on the blade .41 is indicated. In Figure 7 the blade 41`is shownrin angular point contact with a cylindrical drumsurface 74. The line X-X is a tangent ,to the surface atthe point of blade contact. The lower .side of the blade Y-Y' establishes an intersecting plane through the point. In Figure, 8. an exaggerated view of a worn blade 41 is shown engaged with the surface 74 of the drum 12. The wearing of the blade has created a new surface' W-W and the point of contact of the .blade has ybeen destroyed. ,InVFigure 9 it is seen that by increasing the original cutting angle a new edge at the point of contact ,with the drum has been established as between the wear plane W-'W andthe plane X-X' tangential to the cylindricalV drum surface 74 through the point. Such adjustments as these necessitate only a slight change of the cuttingangle and are accomplished, with the herein described .structure .without .operational interruption. Movement of `the

eccentrics

37 and 38 by turning the worm Ahandwliejel7.1, while the structure isstill reciprocating, accomplishes 'the changes'indicated with a minimum amountofinconvenienee. As shown'in'Figure ljthe individual' 'movements comprising vthe compound movement of a"gblade41'areindicated by the phantom line exaggeratedV positions aandb.

'Ini'Figure 6 a double'jdrum 'dryer y13 is shown-toillustrate `-a double'drum installationl of a doctor `knife in'accord witl'x'the 'present invention. -Various` plural installationsware encompassed in the scope -of thef-described structure. 'With particular reference -to :the

doubleL drum'installation (Figure 6)fit willV be seen that` the doctor knife assemblies ,compriseeifective-tie rods rendering-theentire structure more rigid despite the i constantoscillation of the `blade 41. `VThe'tie-rod effectl of the described doctorgknife assembly also counteljacts` the pressur es ontheA end damsl 17 and 18 rtending' to spread Vthel frameil.

It willbe seen that'the'change loftangle can'bemade. without stopping-the vdrumy or the oscillating'knife bar.

Similarly, depth 'of cut is, where desired, independently changed without interrupting continuous process operation. The advantages of; such anl operation are ap-3 cl'rocolate.;pulp,V or `plastic or semi-plastic vmaterialien planar or4 cylindrical'stabilized surfaces. vIn .association with continuous yeastfdryingequipment of all known types the apparatus described has proved itself to be unusually eflicient in minimizing power v,requirements and avoiding process` interruption.

[It is -thus seen that-,a novel and 'highlyl useful-arrangement has' been provided which will allow rdeptheand; cutting -angle adjustmentgof the doctor `blade during p operationand al novel system-has been provided-toA continuously oscillatejthe doctor blade. The apparatus has proved 4economical to fabricate, -1 simple-- to i installand easy4 to maintain.

It willqbe understood Athat-.various modifications of my describedy invention may -bemade and such-modificationsgare -intended to beincluded vinthe scopeof my hereinafter appended claims, unlessthe -scope of' such,

claims negativesAV such inclusion.

Havingg'thus'describedj-my invention, -I/claim:

1.1m a doctor knife wasserriblyg-.the -combinationl in'- cluding: a -main `shaft -paralleling and f ois'et =from-`a served surface, journal means -'supper-ting said LAmain shaft; rcylindrical veccentric@members l operably secured to said main :shaft-in aligned-spaced relation.' thereon; a cylindrical case-'rotatablymounted over said-.eccentric members; means-within said case securing -said-.. shaft to said'casefor `axial-movement therewith; means'for selectively rotating said `shaft on its Vaxisgl-and ai knife support'rigidly longitudinally -and substantiallytangentiallymounted-fon said'cylindrical case and having-=a surface engaging bladeyattached thereto.

2. In a"doctorlknife-assemblyforserving-Ua #moving surface, the combinationincluding: a--main-shaft'paralleling andeoifsetf-from-a served surface, saidfmain shaft Ahaving a ,concentric longitudinal boreextending from one end-'thereof' and terminating `in.v a-radial longitudinal `s lotted guideway through 'the wally of saidmain shaft;l journal -means supporting said :main shaft; va

grooved -receiving -ring -mounted over-said -Inainl shaftl having a circurnferential keyway within-#the inner sur-` face thereofyaldrive shaftjournaled Within: the longitudinal-bore of, said main shaft; a-drivejpin-insertable. through sraidjmain shaft-guideway andjengageablewith` said circumferentially groovedreceiving ring and said drive pin being attached to saiddrive shaft;-a cylindrical case over said main shaft; and a reciprocating drive axially oscillating said drive shaft and said cylindrical case.

3. In a doctor knife assembly for serving a moving surface, the combination including: a main shaft par alleling and offset from a served surface, said main shaft having a concentric longitudinal bore extending from one end thereof and terminating in a slotted guideway through the wall of said main shaft; journal means supporting said main shaft; cylindrical eccentric members operably secured to said main shaft in spaced relation thereon; a cylindrical case rotatably mounted over said eccentric members; a grooved receiving ring xed to said case and having the groove thereof in cooperating alignment with the slotted guideway of said main shaft; a drive shaft journaled within the longitudinal bore of said main shaft, said drive shaft having a projection insertable through said main shaft guideway and engageable with said grooved receiving ring; eccentric adjustment means keyed to said main shaft; rotating means adjustably secured to said cylindrical case; a reciprocating drive operably secured to said drive shaft; and a knife support rigidly and substantially tangentially mounted on said cylindrical case having a surface engaging blade attached thereto.

4. In an oscillating doctor knife apparatus, for adjusting a doctor blade to a served surface independently from the motion of such surface and the oscillation of such blade, the combination including: bearing supports; a partially tubular main shaft in said bearing supports in parallel relation with a served surface and having a longitudinal slot through the tubular Wall portion; a drive shaft journaled concentrically in the tubular portion of said main shaft; a pair of eccentrics keyed to said main shaft in spaced relationship; a cylindrical case in close tolerance rotational engagement over said eccentrics and carrying ak knife blade; a grooved receiv ing ring in said case retained by said case from longitudinal movement; a drive pin projecting from said drive shaft through the slot in said main shaft and engaged in the groove of said receiver ring; geared means for rotating the said main shaft and said eccentrics; collarlike brackets lockably engaging the ends of said cylindrical case; lever arms depending from said brackets; actuating means for arcuately moving said lever arms thereby rotating said cylindrical case; set pins locking said brackets to said cylindrical case; and a reciprocating device longitudinally oscillating said drive shaft and said case.

Bouda June 18, 1929 Hornbostel May 17, 1949