US2640307A

US2640307A - Multiple lift type disk harrow

Info

Publication number: US2640307A
Application number: US162764A
Authority: US
Inventors: Robertson Jackson Perry
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-05-18
Filing date: 1950-05-18
Publication date: 1953-06-02
Anticipated expiration: 1970-06-02

Description

June 2, 1953 J. P. ROBERTSON 2,640,307

MULTIPLE LIFT TYPE DISK HARROW Filed May 18, 1950 6 Sheets-Sheet 1 36' 619 L9 60 2 54 I 7 I a;

30 7 5? j /0 63a 65a IN V EN TOR.

J. P. ROBERTSON MULTIPLE LIFT TYPE DISK HARROW June 2, 1953 6 Sheets-Sheet 2 INVENTOR. my ywfwvfop/w 477'0R/Y6Y Filed May 18, 1950 June 2, 1953 J. P. ROBERTSON MULTIPLE LIFT TYPE DISK HARROW 6 SheetsSheet 3 Filed May 18, 1950 INVENTOR; 2 lofiewfoow,

Jacfibow gig/u;

ATTOR VFY June 2, 1953 J. P. ROBERTSON MULTIPLE LIFT TY PE DISK HARROW FiledMay 1 1950 6 e heet 4 47a I/II m 1953 J. P. ROBERTSON 2,640,307

MULTIPLE LIFT TYPE DISK HARROW Filed May 18, 1950 S Sheets-Sheet 5 Y INVENTOR.

June 1953 J. P. ROBERTSON 0 MULTIPLE LIFT TYPE DISK HARROW Filed May 18, 1950 s Sheets-Sheet 6 IN V EN TOR;

UTE-E5 fie Patented June 2, 1953 UNITED- STATES PATENT OFFICE MULTIPLE LIFT TYPE DISK HARROW Jackson Perry Robertson, Columbus, Miss.

Application May 18, 1950, Serial No. 162,764

My invention relates broadly to agriculture equipment and more particularly to a lift type multi-disc harrow.

This application is a continuation-in-part of my application Serial No. 35.805 filed June 29, 1948 for Multiple Lift Type Disc Harrow.

One of the objects of my invention is to provide an improved construction of multiple disc harrow including means for conveniently and rapidly converting a single unit harrow to a multiple unit harrow and vice versa and maintaining the harrow in such converted condition throughout a desired operation.

Another object of my invention is to provide a construction of multiple unit harrow in which a screw-type strut is provided for maintaining multiple unit harrow in ganged position while being readily adjustable to a position permitting the elevation of certain of the gangs for operating the harrow as a single unit implement.

Still another object of my invention is to provide an improved construction of pivot means for interconnecting the unit of a multiple unit harrow for insuring rigidity of the chassis structure of the implement during ganged operation thereof.

Still another object of my invention is to provide an improved construction of mounting means for the-disc gangs of a multiple disc harrow for facilitating replacement and repairs to the equipment.

Still another object of my invention is to provide an improved construction of hinged connection between the frame sections of a multiple gang harrow for facilitating orientation of one frame section with respect to an adjacent frame section when converting from multiple unit operation to single unit operation and vice versa.

Still another object of my invention is to provide a construction of journalling means for the units of a multiple gang harrow for facilitating rotation of the harrow discs during propulsion of the harrow.

A still further object of my invention is to provide adjustable means for a multiple disc harrow for controlling the depth of penetration of the earth by the harrow discs, the adjustable means being accurate and precise for controlling the depth of penetration of the earth by the discs with corresponding accuracy.

Still another object of my invention is to provide an improved construction of locking means for maintaining the multiple units of the harrow in linearly aligned relation during harrowing operations.

Other and further objects of my invention reside in the improved features of construction of the multiple gang harrow set forth in the specification'hereinafter following by reference to the accompanying drawings in which? 7 Claims. (01. 559-30 Figure l is a plan view of the improvedmultiple unit harrow of my invention; Fig. 2 is a side elevational View of the multiple unit harrow of my invention looking in'the direction of arrow A in Fig. 1; Fig. 3 is a view similar to the view shown in Fig. 2 with one of the units of the multiple unit harrow raised to elevated position; Fig. 4 is an enlarged transverse sectional view taken substantially on line 44 of Fig. 1 showing the arrangement of the harrow discs in one of the harrow units; (Fig. 5 is a horizontal sectional view taken substantially on line 55 of Fig. 4; Fig. 6 is a fragmentary transverse sectional view taken substantially on line 66 of Fig. 5; Fig. 7 is a fragmentary vertical sectional view taken substantially on line 'i-I of Fig. 5;

Fig. 8 is an elevational view of one of the bearing members employed for the suspension of the harrow gangs in the structure of my invention; Fig. 9 is a transverse sectional view taken substantially on line 9--9 of Fig. 2 showing the adjustable means for elevating and lowering the harrow units for controlling the depth of penetration of the harrow discs; Fig. 10 is a vertical sectional view taken substantially on line ill-I0 of Fig. 2; Fig. 11 is an elevational view partially in section of the adjusting means employed in the multiple unit harrow structure of my invention; Fig. 12 is a transverse sectional view taken substantially on line 12-42 of Fig. 11; Fig. 13 is a fragmentary plane view on an enlarged scale of the hinge structure provided by the multipleunits of the harrow of my invention; Fig. 14 is a transverse sectional view taken substantially on line i l-l4 of Fig. 13; Fig. 15 is a transverse sectional view taken substantially on line l5l5 of Fig. 13; Fig. 16 is a fragmentary front elevational view looking in the direction of arrow B- in' Fig. 13 and. showing the locking means for the harrow sections before insertion of the securing bolt; Fig. 17 is a view similar to the view shown in Fig. 16 but illustrating the locking bolt in position, the view being taken substantially on line 17-11 of Fig. 13; Fig. 18 is a transverse sectional view taken substantially on line Iii-i8 of Fig. 13; Fig. 19 is a transverse sectional view taken substantially on line l9-l9 of Fig. 13; Fig. 20 is a transverse sectional view taken substantially on line 20-40 of Fig. 1; Fig. 21 is a vertical sectional view taken substantially on line 2|"-2| of Fig. 20 and Fig. 1; Fig. 22 is a side elevational view of a modified form of my invention by which the rear harrow units may be selectively maintained in predetermined angular positions with respect to the forward harrow units,

Fig. 23 is a view similar to the view shown in- Fig. 22 but'showing theremote rear harrow unit raised and maintained in a 90 position with respect to the plane of the axes of the forward harrow units; Fig. 24 is a fragmentary plan view of the front and rear frame structures utilized in the form of my invention shown in Figs. 22-23 and showing the special construction of hinge members which I provide for selectively maintaining the rear harrow units in selected angular relation to the forward harrow units; Fig. 25 is an enlarged fragmentary plan view showing the structure of one of the hinges'employed inthe structure of Figs; 22-2 l; Fig. 26 is a verticalsectional view taken on the line 26-45 of Fig. 25; and Fig. 27 is a vertical sectional view taken on line 21-27 of Fig. 26.

Myinvention i directedto the type of multiple unit harrow described in my co-pending application No. 35,895 supra ofwhich this application is a: contmuation-in-part and wherein I provide means. for adjusting the depth of penetration of the earthby the harrow discs. I provide a leading and trailing or front and rear harrow unit where the leading. harrow unit is pivotally connected to a frame which couples to the hitch connected to the tractor. The trailer harrow unit; is: pivotally connected with the leading harrow unit through special hinge means. and may. be locked in coplanar relation by an arrangement of special bolt fittings in accordance withmyinvention. The entire harrow structure may; be elevatedv or lowered by special screw means manually adjustable to precisely and accurately, regulate the depth of penetration of thevearths surface by the harrow discs. When the multiple :unit harrow structure is to be operated in singlegang arrangementinstead of multiple gang arrangement the locking bolts are removedand the trailing. unit is moved to a posidon-superimposed over the leading harrow unit. The mass of the trailing harrow unit then becomes effective as ballast in aiding in the penetration of the earth by the discs of the leading har ow-u i I- -provide specialbearing and mounting means for-the gangs. ofdiscs to facilitate rotation of therdiscsas the-harrow ispropelled by the pulling-tractor. Completely replaceable gang units ardproyided accordance with my invention for facilitating-'- replacement and repair of the narr w;

Referring to th drawings in more detail,- reference character I designates a hitch frame extending in a vertical direction and providing means for connection to a tractor through the lift arms designated at 2, 3 and t extended-forwardly to thetractor. The lift arms 2, 3 andi" which arecarried bythe angle frame member to.

of the forward substantially horizontally extending. frame member 8. The substantially horizontallyi'extending frame member 8 provides mquntingmeans. for sets of harrow discs which are illustrated; more particularly in Fig. l. The substantially. horizontally extending frame membend issubstantiallyvin the shape of a trapezoid and is laterally braced to provide a rigid frame by the angularly disposed angle frame members 9 and I8. These angularly disposed angle frame members 9 and i8 serve in coaction with the side frame angle members H and [2 as a support for the sets of harrow discs shown more particularly inFig. 4.

The sets of harrow discs are arranged to revolve as the harrow is drawn forwardly over the field to be cultivated. The sets of harrow discs are represented mounted in their operative positions beneath the substantially horizontally extending frame 8'at id and i5 and consist of assemblies bolted together by bolt members 16, one of the ends of which is indicated in Figs. 2 and 3. The disc assemblies Hi and it are symmetrical in arrangement and are indicated as, consisting of harrow discs i1, i8, i3 and 2.0 assembled-together in spaced relation by sleevelike spacer means indicated at 21, 22 and 23 con stituting the assembly i i. A reserve arrangement of disc and spacer members constitutethe assemblyin harrow unit 15 consisting of spaceddiscs Ha, 48a, to and 28a, spaced by spacer members Zia, 22a and 23a, corresponding to'discs. i7, l8, l9 and 29 andspacer members M, 22' and 23 of the harrowdiscassembly M. The axesof the harrow disc assemblies hi and lfi-extend at an obtuse angle with respect to each other and with respect to the front of theframe member 8. The harrow discs are scalloped at their. peripheral edges for pulverizing th earth. The spacer members 2| and-23'ofharrow disc assembly it are journalled in bearings Zdand 25.d epending from the horizontally extending frame member 8 while sleeve members-21a andiiia-are journalled in bearings 24a and 250. depending from the horizontally extending'frame memben 8. Inasmuch as the detailed constructionpf the bearings and the detailedassembly-of the hare row disc units it and 15 are similar to the structure and-mounting of the rearwardly disposed harrow units, reference is made to the descripa tionhereinafter following of the rearwardly dis posed harrow units 26 and Zlfor a more com.- plete understanding of both the mounting and assembly of the harrow units.

I arrange in a positioncoplanar. with the horizontally extending frame. member 8 a pair of.

frame members

28 and 29 disposed rearwardly of the frame member 3. The frame members 28; and 29 are individually hinged to the frame member 8'by means of very special constructions of hinges which are illustrated more clearly in Figs. l3, l4 and 15. Referring toFig. 13. it willv be observed that the rearwardly extending angl frame 813 of frame member 8 provides a support for pairs of upwardly extending plate members Ella and 31a which are welded to the top ofangle member 81) in spaced positions thereonandextend beyond the rear edge of angle -member 8b. The rear frame 29 which is coplanar-.with-the forwardly arranged frame member 3. is provided on its leading edge fram 29' with apair otter-- tically extending spaced

plate members

32a and 33a which extend between the spaced late members Staand 3la-and are pivotallyconnected thereto by bolt members 340: width-enabling, frame member 29 to be raisedfrom a substantially coplanar position with framev membertas represented in Figs. 1 and 2 -to. a position'superimposed overthe harrow disc assemblies carried by framemember 8. When the reaizframe mem her- -29 ispositioned coplanar with then-forwardly; frame r. 13- 1 ngle framesgfltpandizsi abut each other as shown more clearly in Figs. 14 and 15. The

frame members

29 and 8 are maintained in the said coplanar relation by means of a locking bolt 36a which extends through a pair of depending lugs represented at 31a and 38a. The lug 31a is shown more particularly in Figs. 16, 1'1 and 18 as having a substantially U-shaped section which is recessed at the forward portion thereof as represented at 31a to allow the entry of the hexagonally shaped head end 36a of bolt 36a. The lug 38a is formed by a pair of depending plates between which the bolt 360. extends and is secured by washer and nut combination 3611". Thus the bolt 36a is carried in the lug 31a and substantially maintained against dislodgement and passes beneath the angle frames 8b and 29' and between

lugs

31a and 38a for maintaining frame member 29 in coplanar relation to frame member 8. The rear frame member 29" of frame member 29 extends toward the center of the implement and terminates in a depending plate 39a shown more particularly in Figs. 20 and 21. The depending plate 39a carries a bolt member 40 therein which'is directed transversely through a coacting plate 39 slotted at 39' to permit the entry of bolt 40, the plate 39 being carried by the extension 28" of the frame member 28 having complementary parts to the parts of frame member 29 heretofore explained. Thus when frame members 29" and 28" are aligned in coplanar relation they may be locked in this relation by bolt member 49 which is secured in position by tightening nut and against slotted plate member 39 represented in Fig. 21.

The frame member 28 is provided with symmetrically arranged component parts which are identical with the component parts explained in connection with frame member 29 including the

plates

32 and 33 which coact with sets of plates 30 and 3| carried by angle frame 8b of frame member 8, the said plates being pivotally connected by

bolts

34 and 35 all arranged in a manner similar to the correspondingly numbered parts heretofore described by reference characters bearing subscripts a. Similarly the locking bolt 36 is arranged to extend through the depending

lugs

31 and 38 in a manner similar to the arrangement of locking bolt 36a heretofore described. The

frame members

28 and 29 may be independently raised over the frame member 8 as represented for example in Fig. 3 in which the frame member 28 is shown in elevated position while frame member 29 is shown in coplanar position with respect to frame member 8.

The harrow disc assemblies 26 and 21 carried by

frame members

28 and 29 are symmetrically arranged and are displaced from the center of th implement as shown in Fig. 1. The harrow disc assemblies 26 and 21 are disposed on axes extending at an obtuse angle which is symmetrically opposite to the obtuse angle on which the axes of harrow disc assemblies [4 and 15 extend. The discs are arranged in the harrow discs assemblies 26 and 21 in positions which are in echelon with respect to the discs in the forwardly disposed harrow disc assemblies M and I for insuring the pulverizing of the earth as the harrow is advanced over the field. I have designated the harrow discs in the harrow disc unit 26 at 4|, 42, 43 and 44 spaced by

sleeve members

45, 46 and 41 respectively. The component parts of the harrow disc assembly 21 have been designated by corresponding reference characters bearing subscripts a where the discs are designated as lla, 42a, 43a and 44a spaced by sleeves 6 45a, 4Baand 41a. In Fig. 41 have shown the manner of assembling the harrowdiscs with the spacing sleeves therebetween and through which the bolt member Mia-extends and is secured therethrough by the headed end 480/ bearing against plate 490. arrangedat one end of the assembly and extending through plate 50a. at the other end of the assembly and locked by means of nut 48a" at'the end of the assembly. The assembly for discs M, 42, 43 and 44 is carried ou in a similar manner.

The individually hinged

frame members

28 and 29 are each polygonal in shape as represented inplan view in Fig. l and have the angle frames which interconnect the forward and rearward angle frames 28' and 28" and 29' and 29" inclined at an angle extending toward the rear of the implement. "The angle of inclination of the side frame members 28" and 28" and angle frames 29" and 29- is such that when the multiple disc. assemblies are mounted thereon with the axes of the assemblies extending normeal to the direction of th angle frame members 28", 28", 29 and 29" the harrow discs are maintained at the proper obtuse angles for the most efficient operation in coaction with the forwardly disposed harrow units. 14 and i5.

The manner of journalling the rearwardly disposed harrow units 26 and 21 has been illus- 2 trated more clearly in Figs. 4-8 wherein the manner of suspending the bearings from the angle frame members 29" and 29"" has been clearly brought out. It will be observed that bracket members 5Ia and 52a. are secured to the vertically extending flange portions of the angle frame members 29" and 29" respectively by bolt members 53a and 54a. The bracket members 5m and 52a depend downwardly and are provided with horizontally extending portions Ma and 52a which serve. as supporting means :for the

journal boxes

55a and 56a. Each journal box is formed as represented more particularly in Fig. 7 by upper and lower

complementary parts

56a and 56a" which are secured by bolt :members 51a. and 5801. which extend through the horizontally extending flange 52a and are secured by fastening nuts 51a. and 58a to the top thereof. A similar arrangement is provided for connecting bracket 5 la with journal box 55. The parts of the journal box 560. and 56a" enclose the combined spaced member and sleeve bearing 41a. The sleeve bearing 41a is shown in elevation in Fig. 8 as including a multiplicity of .spaced

flanges

41a, 41a", 41a' and 41a"" distributed intermediate the end flanges 41a" and 41a. The

end flanges

41a and 41a" serve as spacer means bearing against the

discs

44a and 43a while the intermediate flanges serve as bearing means to allow control rotation of the disc. assembly within the

journal boxes

55a and 56a. Lubrication is provided through the journal boxes 55a and 5611 through the lubrication ports 69a and 61a. The associated harrow disc unit :26 is mounted in a manner similar to the harrow disc unit 21 on'brackets 5| and 52 employing component parts for the bearings similar to the component described for mounting harrow disc unit 21. l I

I provide very special means for controlling the depth of cut for theharrow foreither of the positions of the-harrow; that is, with the multiple disc units operating in'coplanar relation or with the rearward harrow disc units moved to superimposed position above the forward harrow disc units. "This depth control mechanism is illus- 7 t e e rm rlea r nd es 3 em. -9- Th dept co tr l mechanisi cons ts-9 he r-9 screw members; QLoppositescrew th eaded pitch represented at GZ, and-.63. Screw member, 2 terminates in a block 64 :whichis-piyoted ate5 {to the up r ly extende hit h rame. I. T e-. .crew m mb 5 t mi ates i abhtk fifiwh hi i oted; e ween b cke :t moun ed. on angle na membe 8b att e sc r. p t esh t am? memb 8- A lindr callmemb thi v n e ially extendin screw threaded .cesses 68 and .59 :t re riehtand lef -ha d 5 c threa s t n b.etwee n 'ensesest e. sc hreaded members 6.2 andfie Ahand whe l fis -provid for revolving cylind ical member for retractin or extendi the screw-th eads embers 5 2. an 163 depending uponithe di ectio .o ro atio o .hand wheel ,69. A nut .liLis pry ided-, on; s crew threaded member 82, andcoac .withthe en O screw threaded recess t8 ving ,to *lQGkfjJhB ex.- pension and contraction device into,v a predetermined set position-when adjusted to-a desiredselected, position. .Withjrame members .28 and 29 locked in coplanar relationwith frame member; 8 .the .entire harrow frame-may :be elevated about the pivotal connections lid and .ibwith the tractor hitch frame for therebycelevatingboth the forwardly disposed xharrowcdiseassemblies i4 and 15 asv well. as the. .rearwardly disposed harrow disc assemblies -26. and '21 and clearing the surfaceoverwhich the implement .is operated. :.-When the locking bolts 36-and 36w are removed and ii'ramemembers 2a and e29 shifted to angular positions superimposed over the forwardlydisposed harrowdisc assemblies the double screw device continues to iunctioh to elevate the harrow= disc assemblies 4 d and l 5 above the surface over which the implement operates and-inthisposition the tractor may. move the harrow readily from one location to another d or to and from the field in which i the implementisto be used. Where the de th of penetration of the surface of the earth bytheharrovcdiscs mustbe controlled the double -.scr.ew may beaoperated by hand wheel 69 to exert pressure lbetweenizthe tr actor hitch frame I and the iramesfi and/01:8, -28, and 29 for directin -the frames downwardly and inclined at such an angle that; the harrow-:;discs ;.-willpenetrate :the earths surface.- to the. idesiredtdegree thereby controlling =thesdepthof cultivation by use of the -implement M .Oimyinvention.witlra .very. highdegree of preci- .sion.

1 In Fi s.,.22;+2'7: I, have shown a modified form ,o f ;.my invention in; which. a special hinge con- .struction is .snbstituted. for ithelplate. members :3 i 3 la, and 33and3aheretoiorefldescribed. In this modified. arrangementthe rrame-memhers-zsand 29 are p vi i fi .td l iil l i ltheirainteriorlsides with horizontally extending vertically sdisposed rplate members H. and; did, whichare welded to :the rear frame .mcmhc ssiland 29 resp c ive y, a d project-over thefront rame member 8. =Thefront frame member} parriescoacting vertically .ext ll 1 1 35 'QlalfiSfl-Land 5112a. which; have a peripheral di ension. greater than 180. 'The ,shape .of thee tes i 2 ;;.and 1 52a, -is shown moreclearlyg M g. 26a wheredthercenter. .of the plate is located at 13c displaced above the stop-3.91am; SilllzffiGfiSzDflthB frame. members-- 8; 2 8 and -;2 9. {Ihat =.tc .-say,=the.plates 12and=12c are danger. ;.than:...semi-.circles. and enable the plate members flinand Jltw-tobe-journaled therein by 'holt members M and Ha-which extend through time cen r l a r ur s tlieinnla meme hers I Z; and 12a. enables the trailing frame members. and 29. to. be raised .with respect to the ,leading frame v member 8 about thecenters provided .bybolt members 34. and 34a heretofore described-and thebolt members 14 and Maprovidedin the special hinge units constitutedby plates '1 i.-12 and li and 12a.

The circular plates "and 12a. are eachprovided with spaced apertures which I have designatedv at l5c,-l.6c,-'iia.and 18a inFig. 26 and which correspond to similarly numberedapertnres without the sufiixla -provided inthe correspondinglyidentified plate 12. These spaced apertures are adjacent the periphe ral edge of eac cu ed s t en s ccdat uch incre e ofdistance as will enable bolt members 14 to be detachably extended therethrough for selectively ma nta ni the ear .0 trailing frame. .membe fiend i n. aselect cl ,anenl rpositionwith re- Shee to h o wa mtlc d siframemembe For examplev in Fig. 22 the -re mote harrow unit 25 is shown elevated in a position at approximately 4 with respect to the plane of the-axes of the forward narrow units represented at I4 and is by the passage. of bolts it and i l-a. through apertures/i5 and idea in

plates

12 and 12a. I referv to the aperturesuifi and 15a inorder .todesignate the corresponding apertures in the similar plate members 72. and; 12a.

In Fig. 23 "I have shown. the'remote. trailing narrow unitdt elevated to vertical position in which the. frame 28 is. secured by bolt'M-passing through aperture 7"! in plate T2.

It will also be understood that the rear or trailing

harrow units

29 and 27 may both be moved to. a position directlyover the forwardorleading harrow units it and i5 and maintained in position by bolt members extending through apertures 73 and We in plate -members l2 and 12a.

The other parts of the modified form of equipment shown in Figs. 22-27 are identified with the elements heretofore described in-connection with Figs. n21.

"In the operation of the harrow of my invention the complete unit as shown in'Figl 2 israised when it is desirable inturning the unit around. The entire unit also raised above theground level for transport to and from thelocations in which the unit isto be used. This raising operation is effected by the hydraulic system of the tractor and the three point implement-hook-up attachment which is al art of the tractor. I

Precision control of the depth of penetration ofthe harrow disc blades is effected primarily by the hydraulic system and hook-up attachmerit. The harrow unit is .of the. order of' 73fl lbs. in weight and. the iour discgang's are originally'attached to the main frame at f xed angles. The arrangement is such that there is a tendency for the harrow to produce a deeper depth of penetrationthan isdesirable, and also constitl tesa load resistance that may'be greater than the tractor capacity. Under theseconditionsthedesired cp hof p rat on s rceul edby mov n the hydraulic controL lever on the tractor ,up ,or down for correspondingly angular1y .sh. fting the complete narrow unit,

i si dl werins the. c mp te: narrow unit the hitch frame i remains in a substantially vertical position throughout the up and down movement of the complete unity as. controlled. by the hydra l ys m andhoQk-up a tachmen The frame mh rdeeisnated at: Balsa. rem ns s sub tantially.horizcntalrositicn. Thailand wheel 69 on the cylindrical member 61 may be revolved to operate the screw threaded

members

62 and 63 to regulate the depth of penetration of the rear sets of harrow discs 26 and 21 in relation to the penetration by the front sets of harrow discs M and I5. If the adjustable cylindrical member 61 is revolved to lengthen the effective length of screw threaded

members

62 and 63 the rear end of frame member 8 and the coacting frames 28 and 29 move below a horizontal gear line position and permits the rear sets of blades 26 and 2'! to cut deeper than the front sets of blades M and [5. By reversing the adjustment of hand wheel 69 the cylindrical member and associated screw members 67 are shortened in their effective length so that the frame member 8 and the associated

frame members

28 and 29 will move above a horizontal center line position and permit the front sets of disc blades l4 and. I5 to make a deeper penetration and deeper out than the rear blades 26 and 21. The left and right hand threads on screw threaded

members

62 and 63 coactingwith the cylindrical member or adjustment strut B1 assure a very accurate and exact adjustment of the position of the harrow discs.

By use of the implement of my invention the effective ballast of the implement is readily controlled by either the distributing of the mass of the harrow units in coplanar relation as represented in Figs. 1 and 2 or concentrating the effective mass of the harrow units by the superimposed relation of the multiple disc units as represented by one of such units in the position illustrated in Figs. 3, 22 and 23. I have found the double screw device of my invention highly effective in the precision control of the depth of cultivation.

While I have described my invention in certain of its preferred embodiments which have been found to be particularly effective in production, manufacture and use, I realize that modifications may be made and I desire that it be understood that no limitations upon my invention are intended other than may be imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A multiple lift-type disc harrow comprising a coupling frame connectible to a tractor, a frame member connected with said coupling frame, gangs of discs carried by said frame member, a pair of separate frame members disposed side by side individually hingedly connected with the rear of said first mentioned frame member, and movable through an orbit appreciably greater than 90 degrees in the direction of said first mentioned frame member, gangs of discs carried by said pair of frame members, said first mentioned frame member carrying connecting means on the trailingedge thereof, and said pair of separate frame members carrying connecting means on the leading edges thereof aligned with the aforesaid connecting means, and disconnectible means interconnecting the aligned connecting means on both said frame member and the rearwardly disposed separate frame members for maintaining said pair of frame members in coplanar relation with respect to said first mentioned frame.

2. A multiple lift-type disc harrow as set forth in claim 1 which also includes additional disconnectible means interconnecting said pair of separate frame members, all of said disconnectible means when disconnected permitting said separate frame members to be individually and separately moved from a coplanar position with respect to said first mentioned frame member to a position over and above said first mentioned frame member.

3. A multiple lift-type disc harrow as set forth in claim 1 in which said pair of separate frame members have individual widths which are substantially one-half the width of said first mentioned frame member and where said pair of frames may be selectively oriented to a position over said first mentioned frame.

1. A multiple lift-type disc harrow as setforth in claim 1 in which the connecting means on the trailing edge of said frame member are substantially U-shaped and depend downwardly beneath the said frame member and wherein the connecting means on the leading edges of the pair of separate frame members comprise depending spaced members extendin in alignment with the aforesaid U -shaped members and wherein the disconnectible means interconnecting the aligned connecting means on both said frame and the rearwardly disposed separate frames constituted by both members extend through said U-shaped members and between said depending spaced members and are fastened with respect thereto.

5. A multiple lift-type disc harrow as set forth in claim 1 in which the connecting means on the trailing edge of said first mentioned frame member depend beneath the plane of said frame member and where the connecting means on the leading edges of said pair of separate frame members depend beneath the planes of said separate frame members in alignment with the aforesaid connecting means and wherein the disconnectible means interconnecting the aligned connecting means extends below the planes of both said frame and said pair of frame members when said pair of frame members and said frame member are disposed in coplanar relation.

6. A multiple lift-type disc harrow as set forth in claim 1 in which said pair of separate frame members abut with each other at the trailing edges thereof and have disconnectible means for fastening the rear edges of said pair of frame members in coplanar relation with respect to said first mentioned frame member and in coplanar relation with each other.

7. A multiple lift-type disc harrow as set forth in claim 1 in which said pair of separate frame members terminate in mutually abutting menibers wherein one of said members carries a disconnectible means therein and the other of said members includes a downwardly disposed substantially V-shaped notch operative to engage said disconnectible means when said pair of separate frame members are disposed in coplanar relation with respect to said first mentioned frame member and in coplanar relation with each other.

JACKSON PERRY ROBERTSON.

References Cited in the file of this patent UNITED STATES PATENTS Number