US2166678A

US2166678A - Disk harrow

Info

Publication number: US2166678A
Application number: US144650A
Authority: US
Inventors: Brenneis Louis; John F Schuck
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1937-05-25
Filing date: 1937-05-25
Publication date: 1939-07-18
Anticipated expiration: 1956-07-18

Description

July 18, 1939 l.. BRENNEIS Er AL 2,156,678

DI SK HARROW Filed May 25, 1937 5 Sheets-Sheet 1 July 18, 1939. L.. BENNEls E-r AL 2,165,578

` DISK HARRow l Filed May 25, 1957 5 Sheets-Sheet 3 ATTORNEYS. A

July 18, 1939. x.. BRENNEIS 1=:r AL 2,166,678

DISK HARROW 5 Sheets-Sheet 5 Filed May 25, 1937 A r ToR/vfrs.

Patend July 18, 1939 UNITED STATES PATENT OFFICE DISK HARROW Delaware Application May 25, 1937, Serial No. 144,650

14 Claims.

Our invention relates to. earth-working implements, and is particularly applicable to disk harrows of the two-gang tandem type.

One of .the objects of our invention is to relate the two gangs mechanically to each other and to the associated tractive means by a novel interconnecting linkage that will automatically seek a position of equilibrium with the two gangs of the harrow diverging at a desirable angle, and will substantially maintain that position against the tendency of the gangs to close together when the harrow is operatedon sloping ground.

In one form of the invention it is our purpose to provide automatic means to limit the angle of divergence when the harrow is employed on soft ground or encounters a soit spot in the area being worked. With respect to the interrelationships existing among the two gangs and the tractive means, we have the further object of proy viding a wide latitude of adjustment in the linkage whereby the working characteristics of the harrow may be varied to meet the requirements of particularly operating conditions.

Another of the 'objects of our invention is to provide interconnecting means whereby the harrow may be oiset either to its closed or, its open side, and, here again, we propose to provide a substantial range of adjustment for .the extent of such oset.

A further object of our invention is to make provision in the construction of the aforementioned linkagefor automatically moving the gangs out of normal divergent relationship when the harrow is turned in a. direction towards its open side. In some forms of our invention it is our object merely to bring the two gangs into substantially parallel relationship preparatory for such a turn, but in most forms of our invention we propose to move the two gangs into opposite divergence to actively favor turning of the harrow in the new direction.

In the transportation of a two-gang harrow to and from a working area, it is essential that the two gangs be maintained in the parallel or nonoperative disposition. In one form of our invention it is our object to so design the interconnecting linkage thatyit may be adjusted to seek a position ot equilibrium with the two gangs in parallel relationship. In another embodiment of our invention it is our object to provide a releasable means to lock the linkage in rigid disposition with the two gangs parallel.

A further object of our invention is to provide latch means on the harrow that may be readily .manipulated by the operator from his seat on the tractive means to releasably lock the interconnecting linkage with the two gangs of the harrow in parallel position. In the preferred form of our invention we propose to incorporate in this latch means for selectively rendering the latch inoperative or operative at the choice of the operator.

The above and other objects and advantages of our invention will be apparent from the detailed description to follow. 1

In the drawings, which are to be taken as illustrative only:

Fig. 1 is a plan view of the preferred form of our harrow in non-operative or traveling disposition;

Fig. 2 is a plan view of a modication of our invention with the two gangs in operative or divergent disposition;

Fig. 3 is a fragmentary section taken as indicated by the line 3-3 of Fig. 2;

Fig. 4 is a view similar to Fig. 2, showing the disposition of the two gangs when the harrow is conducted in a change of direction towards it open side; y

Fig. 5 is a fragmentary section taken as indicated by the line 5-5 of Fig. 1, showing the construction of a latch employed in the preferred form of our invention;

Fig. 6 is a horizontal section taken as indicated by the line 6-6 oi Fig. 5;

Fig. 6a is a fragmentary View of the latchtaken as indicated by the arrow 6a of Fig. 6;

Fig. '7 is a plan view view of the second form of our harrow in operative disposition with the linkage adjusted for operation of the harrow in a path offset to the left of the tractive means;

Fig. 8 is a similar view showing the disposition of the two gangs automatically achieved in a right-hand turn;

Fig. 9 is a pian view of a third form of our harrow shown in traveling or in operative position, this form being distinguished from the second form by reversal of lthe linkage left for right;

Fig. 10 is a third formof a two-gang harrow incorporating the principles of our invention, in which form the interconnecting linkage maneuvers the rear gang by a thrust action instead of a pull action, the harrow being shown in parallel or non-operative disposition;

Fig. 11 shows the harrow of Fig. 10 in divergent or operative disposition;

Fig. 12 is an enlarged fragmentary 'view in plan of the harrow shown in Figs. 10 and 1l, the en- 'larged View serving to show the construction of a pull bar latch incorporated in this form of the invention; and

Fig. 13 is a side elevation of the latch.

In the construction shown in Fig. 1, a front gang or tool-holding member generally vdesignated 20 is connected to a rear gang or toolholding member generally designated 2| through an inter-gang pivot generally designated 22.

The rear gang 2| comprises a plurality of concavo-convex disks 23 mounted on a gang rod 24'that is incorporated in a rear gang frame 25, the frame including the usual rectangular frame extension 21. The front gang 20 is of similar construction comprising a plurality of concavo-' convex disks 28 mounted on a gang rod 29 that is incorporated in a front gang frame 30 having the usual rectangularextension 32. Itis contemplated that in the operating disposititon of the ha rrow, the end 33 of the rear gang and the end 34 of the front gang will be the leading ends,

the concave faces of the disks in each gang' being turned towards the leading ends thereof.

Any suitable pivotal means for connecting the two gangs known to the art maybe incorporated in our invention. We prefer, however, to construct our harrow with the connecting means shown in the drawings,` which means includes a pair of crossed links 3B and 31, a semi-circular member 38 extending from one of the gangs, and a pair of semi-circular members 39 extending from the other gang. In the specific construction shown in Fig.' 1, for example, the semicircular member 38 is a bar mounted on the rear of the front gang frame 30, and the semicircular members 39 are two complementary bars extending flatwise from the rear gang frame 25 to slidingly engage the upper and lower edges of the semi-circular member 38. It will be noted that the semi-circular members 39, in effect, cooperate to confine the semi-circular member 38, and the links 36 and 31 in turn serve to confine the semi-circular members 39, the result being an assembly having an interlocked character.' We have found that such a pivotal connection has certain advantages over other types known in the art, including the tendency to keep the two

gang rods

24 and 29 in a common plane.

As previously stated, the preferred form of our invention is characterized by a novel linkage for inter-relating the two gangs and a tractive means, such as a tractor, for operating the harrow. This linkage,.as depicted in Fig. 1, includes a lateral draw bar 40, a connecting member 4I providing a draft connection between the dra'w bar 40 and the rear gang 2|, a longitudinal draw bar 42, a link 43 interconnecting the two draw bars, and a pull bar 44 associated with th'e draw bar 40 and link 43 for the purpose of providing a draft connection between the harrow and the tractive means. Y

The lateral draw bar 40, which may be an angle-iron, as shown, is connected to the leading end of the front gang frame 20, preferably by means permitting universal movement. For example, the bar may pivot about a pin or bolt 41 carried by a small bracket 48, which bracket, in turn, is pivotally mounted on an arm 49 extending forward from the front gang frame 30, the arm being secured to the frame by suitable means such as bolts 50.

The forward end of the connecting member 4I is pivotally joined to the draw bar 40 near the free end thereof. In the particular construction shown, the connecting `member is a round bar, and the forward end is simply bent for insertion in a suitable aperture in the draw bar 40, a plate 53 being bent around the edge of the draw bar to provide reinforcement at the aperture. The rear end of the connecting member 4I is pivotally joined to the rear gang frame 25 at a point odset from the inter-gang pivot 22 towards the leading end of the gang. To provide such a joint, a plate 54 may be mounted on the front end of the rear gang frame and provided with a bolt 55 extending through an eye in the connecting member 4 I.

ing each point of connection. In the drawings,

the longitudinal draw bar 42 has spaced apertures 59a, 59h, and 59e to receive a bolt 60 in an eye at the end of the link 43, and the lateral draw bar 40 has a series of apertures 63a-63f to receive a bolt 64 that passes through an eye at the other end of the link 43. An apertured plate 65 bent to fit around the edge of the draw bar 40 may be provided with the bolt 64. It will be apparent from the interconnection of the linkage elements thus far described that if the link 43 is freely pivoted to both the draw bars 1 and disposed as indicated, for example, in Fig. l, the link will have no effect on the lateral draw bar 40 `through a considerable range of positions of that draw bar. Through such a range, any forwardly directed force applied to vthe lateral draw bar 40 will be distributed between the leading ends of the two gangframes and will tend to turn the gangs into diverging disposition. By I interconnecting the link 43 and the pull bar 44 to fix the angular relation therebetween, preferably with the pull bar secured to the bolt 64, as shown, we introduce forces, however, that modify the action of the lateral draw bar 40 and the angular relationship of the two gangs. By the introduction of the opposing forces, we achieve a linkage that will automatically seek a disposition in which the forces are in equilibrium, the angular relationship of the two gangs with respect to each other being, in effect, the resultant of those forces. By making provision for varying the angle between the link 43 and the pull bar 44 along with the other adjustments previously described, we are enabled to vary the factors involved in the equilibrium of the linkage and thereby affect not only the divergence of the two gangs in the operation of the narrow, but also the degree of offset of the path of the harrow with respect to the path of lthe tractive means connected to the pull bar.

Adjustability of the angle between the link 43 and the pull bar 44 may be provided in any one of several ways known to the art. For example, we may provide a pair of arcuate members B6 supported between an intermediate point on the link 43 and the end of an arm 61 integral with the link, one of the arcuate members being above and the other below the pull bar 44. These arcuate members are provided with matched apertures 68a-68y, and the pull bar 44 may be substantially registered withl any one of the pairs of apertures either by passing a bolt through the apertures and thepull bar. or, as shown in Fig. 1, by passing bolts through the apertures lying to each side of the given aperture.

When the two gangs are disposed in parallel relationship, as indicated in Fig. 1, the disk har.

row runs forward freely without fighting the ground. This non-operative disposition of the to rely upon some latch means tomaintain thel two gangs parallel temporarily when the harrow is merely traveling. A suggested construction for such a traveling latch is indicated in Fig. 1 and more particularly in Figs. 5, 6, and 6a.

Secured as by bolts 18 to the forward member 1| of the front gang frame 38 is a pair of standards 12. The standards are interconnected by a cross bar 13, thereby defining a rectangular space through which extends the rod 4| that connects the lateral draw bar 40 with the rear gang frame 25. Secured to each standard 12 above the cross bar 13 is a plate 14, the purpose of the two plates being to provide guide means for a vertically movable latch member 15. Each of the plates 14 carries a pair of angle-irons 11 to serve as guide rails for a guide flange 18 extending laterally from the latch member 15.

The latch member 15 is of rectangular configuration with a latching edge 19'adapted to engage a complementary recess 88 in the member 4|. The latch member 15 is formed with a large aperture 82 to receive means for controlling the latch. This control means may comprise, as shown in the drawings, a latch lever 83 pivotally mounted on a pin 84 extending between two latch standards 85, the latch standards being in turn mounted on the cross bar 13. The upper end of the lever 83 has an eye to receive a rope 86, or similar flexible member, for manipulation by the operator, and has a lower end that forks into a pair of operating feet 81 extending into the aperture 82. A suitable spring 88 acting between the lever 83 and a point on the gang frame 30 tends to keep the lever rocked rearward. When an extensive tug by the operator on the rope 86 moves the lever 83 forward to an extreme position, the two feet 81 move upward against a wall 98 of the latch member and raise the latch member clear of the recess 88.

Since the traveling latch is required only when the harrow is being transported, it is desirable to have some means for retaining the latch in an inoperative position while the harrow is working soil, especially since, in the turning movements of the harrow, the recess 88 may come into registration with the latching edge 19 of the latch member 15. For such reason we provide an auxiliary latch 9| mounted on a pin 92 between the two standards 85, the latch being adapted to engage a shoulder 93 on the latch member 15 to hold the latch member elevated at an ineffective position. A suitable spring 94 acting between the auxiliary latch 9| and a pin 95 serves to urge the auxiliary latch continuously towards the latching member 15, so that engagement by the auxiliary latch is automatic-whenever the latching 'member 15 is elevated the required distance.

A feature of our invention is that the traveling latch may be either operatively or inoperatively disposed merely by manipulation of the rope 86 on the part of the operator. The preferred form of the mechanism for changing the traveling latch from inoperative to operative disposition, in other words, for releasing the auxiliary latch 9|, includes a trip finger 96 plvotally mounted to and between the two forks of the latch lever 83 in a position to trip the auxiliary latch 9| in the course of the upward movement of the feet 81. Normally, the finger 96 is held in tripping position against a lug 91 by the action of a spring 98 anchored to a second lug 99. On the downward movement of the feet 81 carrying the finger 96 towards the auxiliary latch 9|, the finger will pivot against the tension of the spring 98 to brush past the auxiliary latch without tripping the auxiliary latch.

'I'he operation of the traveling latch may be -readily understood from the foregoing descrip- "latch member. is not in operative disposition, the

operator gives the rope 86 a slight tug suflcient to release the auxiliary latch 9-| but not suiiicient to cause the two feet 81 of the latch lever to hold the latch member at a height to permit re-ensagement by the auxiliary latch. Arriving at the area to be worked, the operator gives the rope 86 an'extensive tug suilicient to carry the shoulder 93 of the latch member 15 upward into the range of the auxiliary latch 9|. Thereafter, the traveling latch will remain inoperatively disposed so that incidental registration of the recess 88 with the latch edge 19 will not cause the linkage to be locked.

The means previously mentioned for limiting the divergence of the two gangs of the harrow when operating in especially soft soil may comprise simply a split collar |88 adjustably mountagainst either the traveling latch mechanism orl the cross bar 13 overlying the connecting member 4|.

The harrows shown in Figs. 2, 4, 7, and 8 differ from the harrow of Fig. l essentially in the omission of the traveling latch. A means for engagemen't with the collar |88, however, is provided in the form of a short bar |83 mounted on the frame member 1| in spaced relation thereto by suitable bolts |84 and spacers |84a, as indicated in Figs. 2 and 3.

At what disposition of the two gangs of the harrow the interconnecting linkage is in equilibrium depends upon the adjustment of the linkage as a whole. While any one of the various adjustments will more or less aiect both the angle of divergence o f the two gangs and the offset disposition of the harrow with respect to the tractor, nevertheless changes in the angular relation oi the link 43 and the pull bar 44 have the greatest effect on the divergence of the two gangs, and the shifting of the bolt 64 along the lateral draw bar 48 and of the bolt 68 along the longitudinal draw bar 42 primarily affect the offset of the harrow with respect to the tractive means. As the disposition of the pull bar 44 with relation tothe arcuate members 86 is shifted registration with the apertures 00a, the two gangs of the harrow will be increasingly divergent at the equilibrium disposition of the interconnecting linkage. As the connection of the pull bar 44 and the link 43 with the lateral draw bar 40 vis shifted from the aperture 03a towards the aperture 63e of the lateral draw bar, and as the connection of the link 43 to the longitudinal draw bar 42 is shifted 'rearwardly from the aperture 59a. towards the aperture 59o, the oifset relationship of the harrow tends to shift from the left side to the right side of the path of the tractor, the terms right and left being used with respect to the direction of travel.

With the adjustment shown in Fig. 1, if the interconnecting linkage were not locked by the traveling latch, the linkage would come into equilibrium with the gangs slightly divergent and traveling substantially directly behindthe associated tractor. For greater divergence of the two gangs, the pull bar 44 would be adjusted toA the lei't, for example, into registrationwith the aperture 68e as shown in Fig.l 2. 'I'he disposition of the interconnecting linkage would tend to maintain the divergence shown in Fig. 2, and the collar |00 on the connecting member 4| would prevent increase of that divergence in soft ground. .1 In Fig. 7 the pull bar is moved into registration with the aperture 30! to further increase the divergence of the two gangs, and the

bolts

58 and 64 are shifted to the apertures 01a and 63a. respectively to cause the harrow to be oifset to the left. In general, it is more difficult to olfset a harrow towards its closed side than towards its open side, but, as indicated by Fig. 7, our harrow may be readily offset towards its closed side. When the two gangs of a disk harrow are in parallel relationship, the harrow may be turned in either direction,- and when the two gangs of the harrow are in diverging relationship, the harrow may be readily turned towards its closed side. When the two gangs are divergent, however, a turn towards the open side of the harrow may be accomplished only with dimculty if .the divergent relationship is maintained throughout the turn. A feature of our linkage is that in making a turn towards the open side of the harrow, the linkage automatically rotates the two gangs towards each other to favor the desired turn. Thus, when a turn to the right is made with the harrow in the operative `position of Fig. 2, the linkage. automatically reverses the divergence of the two gangs so that during the -course of the turn the right-hand side becomes the closed side, as shown in Fig. 4, the reversed divergence actually favoring the right-hand turn. Likewise, with theharrow in the operative disposition shown in Fig. '1, the linkage automatically reverses the divergence of the two gangs for a turn to the right, as shown in Fig. 8.

In the turning movement of the harrow, a

tendency may be noted for the lateral draw bar directionv towards the open side of the harrow. It may be said that the draw bar 40 is a freely pivoted means for balancing against each other the turning moments ofthe two gangs.

The harrow of Fig. 9 di'ers from the construction shown in Figs. 2, 4, 7, andi! only in the reversal of the linkage, identical numbers being used to indicate corresponding parts. In this particular construction the leading ends of the two gangs are reversed, andthe connections of the two draw bars to the gangs are reversed.

Another form of our linkage that may be incorporated". in a harrowconstruction is indicated by Figs. 10 to 13. In the construction shown, the inter-gang pivot is at one side of the'harrow instead of being centrally located. Thus, an arm |06 extending diagonally forward from the rear gang frame |01 and an arm |08 extending diagonally to the rear from the forward gang .frame |09 are pivotally connected together by a suitable bolt or pin ||0. A lateral draw bar ||3 is pivotally connected by a bolt ||4 to a small plate ||5 that extends forward fromvthe frame |09 near one corner thereof and is also pivotally connected to the forward endiof a link ||6 that extends rearward to control the open end of the rear gang frame |01. The latter pivotal connection may be obtained by simply bending the forward end of the link ||6 downward to pass through a complementary aperturein the draw bar` ||3, the drawing showing a suitable clip ||1 for reinforcement of the, draw bar around the aperture.

T'he link ||6 has an adjustable collar ||3 corresponding to the collar |00, previously described. and adapted to cooperate for the same purpose with a stop means in the form of avshortbar I I9 mounted on the forward gang frame |09.

At the front'of the front gang frame |09, an angle-iron |21 is mounted to provide pivotal connection between the gang frame and a longltudinal draw bar |20. For the purpose of varying,

the points of connection, the angle |21 may have a plurality of apertures |29, as previously described. The forward end of the longitudinal .draw bar |28 is connected with the lateral draw bar |3 by means of a link |30, the link having the same pivotal connection as the rearward extending link ||6, and a forwardly extending pull bar |32. The longitudinal draw bar |28 may have a plurality of apertures |33 as before described, for the purpose of varying the connection between the draw bar and the link |30.

The latch is urged continuously towards engagement with the racks by a suitable spring |44 in tension between the latcih arm and an eye-bolt on the pull bar |32.

Preparatory to transporting this 'particular harrow to the working area, the operator pulls the rope |43 taut to hold the latch in inoperative position while he maneuvers the tractor into the traveling position indicated by Fig. 10. Ordinarily, the maneuver consists simply of backing up` the tractor to close the two gangs of the harrow together. When the harrow is in the required position, the operator releases the rope to ilx the adjustment of the interconnecting linkage.

Upon arriving at the working area, the operator holds the latch open while he eases the tractor forward until the interconnecting linkage is unfolded to a desired degree, and then he releases the' latch to x the angle between the pull bar |32 and the link |30. It will be noted that in moving the two gangs into divergent disposition, the interconnect-ing linkage thrusts rearward on the trailing en'd of the rear gang frame instead of pulling forward on the leading end thereof. A feature of the construction is that the operator may, without leaving his seat on the tractor, conveniently change the angle between the pull bar and the link |30, thus changing the degree of divergence between -the two gangs.

The forms of our inventiondescribed herein in specific detail for the purposes of disclosure and illustration suggest a wide range of modification and substitution without departing from the essence of our concept. We reserve the right to all such modifications and substitutions that properly come within the scope of our appended claims.

We claim as our invention:

1. In a ground-working tool,` the combination of: a front tool-supporting member; a rear toolsupporting member; means pivoting said members for relative movement between parallel and angled positions; draft means including draw bars connected to opposite sides of said front toolsupporting member, a link interconnecting said draw bars, a pull bar having connection with said link and adapted for connection to a tractive vehicle; a draft connection from said draft means to a point on said rear member spaced from the point at which force is exerted upon said rear member by said pivoting means; said connection between said link and pull bar securing said link and pull bar together to transmit forward pull of said tractive vehicle to said draw bars and to said draft connection while said front and rear members occupy relatively angled posilink interconnecting said draw bars; a pull bar` having connection with said link and adapted for connection to a tractive vehicle; means limiting l the anglebetween said members; a draft connection from one of said draw bars to a point on said rear member spaced from the point at which force is vexerted upon said rear member by said pivoting means; said connection between said link and pull bar securing said link and pull bar together to transmit forward pull of said tractive vehicle to said draw bars and to said draft connection while said front and rear members occupy relatively angled positions, and to transmit laterai pull of said tractive vehicle to said link, whereby when the tractive vehicle is turned around the diverging ends o f said members, said rear member is urged into position parallel to said front member; and releasable means for retaining said members in parallel position.

3. In a ground-working implement, the combination of a front tool-supporting member; a

' rear tool-supporting member; means pivoting said members for relative movement between parallel and angled positions; draft means including draw bars connected to opposite sides of said front member and a link interconnecting said draw bars; means adapted to connect said link with a tractive vehicle and to move said link angularly relative to said draw bars under lateral pull of said Vehicle; the connection of one of said draw bars to said front member and the connection of said link to one of said draw bars being adjustable for varying the offset of the implement; and a draft connection from said draft means to a point on said rear member spaced from the point at which force is applied to said rear member by said pivoting means, whereby movement of said draft connection relative to said front member during travel of the tractive vehicle around the diverging ends of said members in angled position urges said rear member towards a position parallel to said front member.

4. In a ground-working implement, the combination of a front tool-supporting member; a rear tool-supporting member; means pivoting said members for relative movement between parallel and angled positions; draft means including draw bars connected to said front member and a link connecting s aid draw bars; a-pull bar connected in xed position to said link and adapted for connection to a tractive vehicle, the connection of said pull bar to said link, the connection of one of said draw bars to said front member, and the connection of said link to one of said draw bars being adjustable for varying the offset of the implement; and a draft connection from said draft means to a pointon said rear member spaced from the point at which force is applied to said rear member by said piv- ,oting means, whereby movement of said draft connection relative-to said front member during travel of the tractive vehicle around the diverging ends of said members in angled position urges said rear member towards a position parallel to said front member.

5. In a ground-working implement, the cornbination of: a front tool-supporting member; a rear tool-supporting member; means pivoting said vmembers for relative movement between parallel and angled positions; draw bars connected to said front member; a link connecting said draw bars; a pull bar connected in fixed position to said link and adaptedv for connection to a tractive vehicle, the connection of said pull -bar to said link, the connection of one of said draw bars to said front member, and the connection of said link to one of said draw bars being adjustable for varying the offset of the implement; and a draft connection from one of lsaid draw bars to a point on said rear member nected to said front member; a link connecting.b

said draw bars; a pull bar adapted for connection to a tractive vehicle and'adapted for connection to said link in variable angular relationships therewith for varying the offset of the implement, the connection of one of said draw bars to said front member, and the connection of said link to one of said draw bars being adjustable for varying the offset of the implement; and a draft connection from one of said draw bars to a point on said rear member spaced from the point at which force is applied to said rear member by said pivoting means, whereby movement of said draft connection relative to said front member during travel of the tractive vehicle around the diverging ends of said members in angled position urges said rear member towards a position parallel to said front member.

7. In an offset disk harrow, the 'combination of a forward frame; disks carried by said frame; a rearward frame; disks carried by said rearward frame; means pivoting said frames for relative movement between parallel and angled positions; draw bars connected to said front frame; a link pivotally connected to said draw bars; means for adjusting the connection of said link to one of said draw bars; a rigid member connecting one of said draw bars to said rear frame; a pull bar adapted for connection to a tractive .vehicle and pivoted tosaid link and to said one draw bar -at their adjustable 'connection; and locking means releasable by the driver from his position on the tractive vehicle for securing said pull bar in the desired angular relationship with said link, whereby the travel of theftractive vehicle around the open ends of said frames in angled position moves said draw bars relative to said link to exert force through said rigid member to said rea'r frame urging said rear frame into a position parallel to said front frame.

8. In an oiset disk harrow, the combination ofi a forward frame; disks carriers by said frame; a rearward frame; disks carried by lsaid rearward frame; means pivoting said frames for relative movement between parallel and angled positions; draw bars connected to said front frame; a link pivotally connected to said draw bars; means for I at their adjustable connection; releasable means for retaining said frames in parallel position; and locking means releasable by the driver from his position on the tractive vehicle for securing said pull bar in the desired angular relationship with said link, whereby the travel of the tractive vehicle around the open ends of said frames in angled position moves said draw bars relative to said link to exert force through said rigid memaieaovs ber to said rear frame urging said rear frame into position parallel to said front frame.

9. In a draft frame for an implement including two tool-supporting members pivoted for rela\ tive movement between parallel and angled'positions, the combination of: a first draw bar adapted for pivotal connection to the front toolsupporting member` on one side of its center line; a second draw bar adapted for connection to the front tool-supporting member on the other side of its center line; means for varying the connection of the second. draw bar to the front toolsupporting member among a plurality of positions spaced parallel to the transverse axis of the front tool-supporting member; a link pivotally connected between the two draw bars; means adjustable longitudinally of said rst draw bar for pivotally connecting said link with said iirst draw bar, and means adjustable longitudinally of said second draw bar for pivotally connecting said link with said second draw bar.

10. In a ground-Working tool, the combination of a front tool-supporting member; a rear toolsupporting member; means pivoting said members for relative movement between parallel and angled positions; a draw bar having one point connected with one side of the front tool-supporting member. to one slide of said pivoting means and another point link connected with the rear tool-supporting member; and a bellcrank pivotally connected at its axis with said draw bar, one arm of said bell-crank being connected with said front tool-supporting member on the opposite side of said pivoting means from said rst point of connection with the front toolsupporting member, the other arm of said bellcrank constituting the pull bar for the groundworking tool.

11. In a ground-Working too1,'the combination of a front tool-supporting member; a rear tool-supporting unember; means pivoting said members for relative movement between parallel and angled positions; a linkage iiexibly interconnecting said tool-supporting members, said linkage including a draw bar having one point `con-v nected with one side of the front tool-supporting member to one side 'of said pivoting means and another point link connected with the opposite side of the rear tool-supporting member, a pull bar connected with said draw bar for pivotal movement relative thereto about a vertical axis intermediate said previously lmentioned points, whereby the two tool-supporting members cause opposite turning moments to be exerted on said draw bar, an arm movable with said pull bar about said vertical axis, and connecting means between said arm and said front member permitting pivotal movement of said pull bar and arm about said vertical axis and adapted to transmit forward pull from said arm to said front member.l` Y

12. In a ground-working tool, the combination of: a front tool-supporting member; a rear toolsupporting member; means pivoting said members for relative movement between parallel and angled positions; a draw bar having one point connected with the front tool-supporting member and another point link connected with the rear -tool-supporting-member; a second draw bar connected with the front tool-supporting member; and a bell-crank pivotally connected at its axis with said first draw bar, one arm of said bell-crank being connected with the second draw bar and the other arm of the bell-crank constituting the pull bar for the ground-working tool, said bell-crank being adjustable in the angular relation of its two arms.

13. In a ground-working tool, the combination of a front tool-supporting member; a rear toolsupportingmember; means pivoting said members for relative movement between parallel and angled positions; and a linkage flexibly interconnecting said tool members, said linkage including a draw bar having one point connected with the front tool-supporting member to one side of said pivoting means, connecting means between another point'onvsaid draw bar and a point on the rear tool-supporting member to one side of said pivoting means, means operatively connected with said connecting means to limit the movement of the linkage, a. pull bar connected with said draw bar for pivotal movement relative thereto about a vertical axis intermediate said rst mentioned points of said draw bar and adapted for connection with a tractive vehicle, an arm movable with said pull bar about said vertical axis, and connecting means between said arm and said front member permitting movement of said arm and pull bar about said vertical axis and adapted to transmit forward pull fromsaid arm to said front member.

14. In a ground-working tool, the combination of: a front tool-supporting member; a rear toolsupporting member; means pivoting said members for relative movement between parallel and angled positions; and a linkage flexibly interlconnecting said tool members, said linkage including a draw bar having one point connected With the front tool-supporting member to one side of said pivoting means, connecting means between another point on said draw bar and a point on the rear tool-supporting member to one lo side of said pivoting means, a latch cooperative with said connecting means to releasably retain the linkage at a desired position, a pull bar connected with said draw bar for pivotal movement relative thereto. about a vertical axis intermedi- 15 ate said first mentioned points of said draw bar and adapted for connection with a tractive vehil cle, an arm movable with said pull bar about said vertical axis, and connecting means between said arm and front member permitting movement of 20 said arm and pull bar about said vertical axis and adapted to transmit forward pull from said arm to said front member.

LOUIS BRENNEIS. CARLOS n NAJERA. JOHN F. sCHUCK.