US2511070A - Two-way plow - Google Patents

Description

J- M. MARKEL June 13, 1950 TWO-WAY PLOW 4' Sheets-Sheet l Filfed Sept. 15, 1945' v m N June 13, 1950 ,J. M.'MARKEL 2,511,070

TWO-WAY PLOW Filed Sept. 13, 1945 4 Sheets-Sheet 2 @MJNDM J. M. MARKEL TWO-WAY PLOW June13, 1950 4 Sheets-Sheet 3 Filed Sept. 13, 1945 J. M. M ARKEL June 13, 1950 4 TWO-WAY PLOW 4' Sheets-Sheet 4 Filed Sept. 15, 1945 ED EIVENTOR iwmwawa Patented June 13, 1950 UNITED STAT ES PATENT OFFICE TWO-WAY PLOW John M. Markel, Rockford, IIL, assignor to J. 1. Case Company, Racine, Wis., a corporation of Wisconsin 18 Claims.

This invention relates to improvements in'two way plows.

It is a primary object of the invention to improve, sirnplify and make more certain of operation the controls of a generally conventional two way plow.

One broad object of the invention is to combine the convenience of automatic operation with the trouble free and relatively frictionless movement of oscillatory, as distinguished from reciprocatory, parts. Another broad object of the invention is. to provide a plow of the character described in which the wheels are not merely automatically self-adjusting as to height, but are positively actuated in each cycleof operations toward their position-s resulting in maximum height of the main frame, from which they may move successively by gravity'to the other positions.

Since the objects otherwise pertain specifically to the particular controls hereinafter to be disclosed, additional purposes of this invention will appear more fully in connection with the following disclosure thereof.

In the drawings:

Fig, 1 is a plan view of a device embodying the invention.

Fig. 2 is a view inside elevation of the device shown in Fig. 1 as it appears with the wheels in road position.

Fig. 3 is a fragmentary view in side elevation of the device shown in Fig. 1 as it appears when adjusted for plowing.

Fig. i is a fragmentary front elevation, on an. enlarged scale of the device shown in Fig. 1, portions thereof being broken away.

,Fig. 5 is a fragmentary plan view on an enlarged scale of the device shown in Fig. 1, portions thereof being broken away.

Fig. 6 is a detail view taken in section on the line 66 of Fig; 4.

Fig. 7 is a detail view taken on the line 1-1 of Fig. 4.

Figs. 8 and 9 are fragmentary detail views similar to Fig. 7, showing the parts in different relative positions.

Fig. 10- is a fragmentary detail view in perspective illustrating some of thepa-rtsshown in Figs. 6 tov 9.

The general. organization will first be described in, order that the application of this invention thereto will be appreciated,

Themain frame I5 has the shape, in plan, of. a rearwardly opening U, comprising-side members 16, IT, and a front which includes the forwardly converging members l8, l9, joined by a cross member 20. At their forward ends the converging members I8 and [9 are inclined downwardly and joined at 2| to provide a support for the kingpin 22 on which the fabricated drawbar 23 is pivoted. The drawbar has means at 24 for the adjustable support of the hitch 25.

At the rear ends of the frame sides [6 and I1, offset'bracket 26, 21 provide outboard bearings for the axle rock shafts 2-8, 29, which extend through, and have bearings in, the frame sides l6, IT and the offset brackets 2-6, 21. The axle rock shafts have crank portions 38, 3|, which support the axles 32, 33 on which the wheels 35, 36, are rotatably journalled. Braces 31, 38 may connect the respective cranks with the forwardly projecting arms 39, 40, with which the respective axle rock shafts 2B, '29 are provided, the purpose of which will hereinafter be described.

The shaft 42 extends through, and is journalled in, the frame sides l6 and I1 and the offset brackets 26, 21, slightly to the rear of the axle rock shafts 28, 29. Shaft 42 provides a rotatable mounting for the invertible subframe 43 to which the beams 44, 45 of the respective plow bottoms 46, 4'5. are attached. The invertible subframe 43' may be provided with a central longitudinally extending frameelement 48 to which beams 44, 45 are connected. Also connected to the central frame member 48 are the coulter brackets 49, 49. in which the adjustable stems 50, 5|, supporting the coulter disks 52, 53, are mounted. As plainly shown in Fig. 2, the respective plow bottoms andtheir associatedv coulters are relative- 1y inverted on the subframe 43 so that one set will be held aloft in an inoperative position when the other set is in use. It will, of course, be undcrstood that the number of plow bottoms attached to the subfra-me may be multiplied in the usual manner, the two shown being illustrative. It willalso be understood that, as is usual in a plow of this type, the plow bottoms 46, 41, are lefts and rights so that, intheir alternate use in successive traverses forth and back across a piece of land, the land may always be turned in the same direction to avoid leaving a broad furrow in the middle of the field.

The controls whereby the'positions of the invertible subframe 45 and the independently adjustable axle rock shafts 28, 29 are regulated and determined in accordance with the present invention will now be described.

During: a plowingoperation, as well as during travel on the road, the forward end of the subframe 43 is normally fixed by a pawl 55 which acts thereon from above and the hooked end '56 of a bell crank 51 which engages the end of the subframe from beneath. Both pawl 55 and the bell crank 5? may be pivoted on the same pintle 58. The tension spring 56 acting on the pawl holds it normally in the position shown in Fig. 6, but permits it to oscillate in a clockwise direction when displaced by the downwardly swinging movement of the end of subframe 43, which always turns counterclockwise in the direction indicated by the arrow in Fig. 6.

The bell crank 51 has a forwardly extending arm at 6B in the path of a roller 6| mounted on handlever 62 for pivotal movement about the shaft 63. The handlever 62 is free of any connection with the shaft 63, being merely supported thereon and secured by collar 64 against displacement axially of the shaft. The handlever 62 may be provided with a laterally projecting anchorage 65 for the tension spring 59 of pawl 55.

When the upper end of handlever 62 is pulled forwardly from the position shown in Figs. 6 and 8, the engagement of roller 6| with the arm 66 of bell crank 51 will disengage the anti-friction roller 66 of the bell crank hook 56 from beneath the subfranie 43, thereby allowing the subframe to swing counterclockwise as viewed in Fig. 9, the subframe being impelled to rotate in this direction due to the drag of the earth on the plow bottom il engaged therein. As soon as the inverting movement of the subframe 43 is commenced, the operator will release the handlever 62 which, subject to the bias of spring 59, will be returned to its normal position where it will intercept the other end of the now inverted subframe 43 to hold the subframe in its inverted position with the plow bottom 46 now in operative plowing position in the earth.

The length of the subframe 43 at each side of the shaft 42 on which it is pivoted is greater than the height of the shaft 42 above the ground. Consequently, as each successive end of the subframe is released in the manner just described it will, in its downward movement, in the course of its counterclockwise rotation, strike the earth and lift the entire frame as the frame is drawn forwardly by the towin tractor. Offset from shaft 52 toward the respective ends of the subframe 43, at each side thereof, are the cam elements 68 so positioned and formed that in the first quarter rotation of the subframe 43, they will engage and release the arms 69, 76, with which the axle rock shafts 28, 29, are respectively provided.

In the positions of the rock shafts respectively shown in Fig. 3, the arms 69 and 10 project at different inclinations but both are in the path of the appropriate cam 68 and will be positively actuated as the subframe inverts. However, as each arm approaches the vertically downward position in which arm 10 of rock shaft 29 is illustrated in Fig. 2, the arm will be released by the cam due to the fact that the cams rotate about the center of shaft 42, whereas the rock shafts 28, 2t oscillate about their own centers, forwardly of shaft 42. Thus the cams 68 will automatically disengage themselves from the respective arms after movin each rock shaft positively to the position illustrated in Figure 2.

The rock shafts have three effective positions, each representing a different location of the wheel with respect to the frame of the apparatus. Fig. 2 illustrates the road position in which the wheel is so far beneath the main frame [5 as to carry the lowermost plow bottom 41 well above the surface of the ground traversed. In Fig. 3

the respective wheels 35, 36 are in the positions they occupy during plowing, the wheel 36 operating in the furrow at the level of the plow bottom 41, while the wheel 35 operates on the land. These various positions of the rock shafts 28, 29 and the wheels and axles supported thereby are determined by a set of stops with which the arms 39, 40 on the respective rock shafts are engageable' These stops will be described as illustrated in Figs. 2 and the stops on the opposite side of the apparatus being similar.

At the end of each of the arms 39, 40 is a roller 1|. In the lowermost position of the wheel respecting the frame as illustrated in Fig. 2, the roller H is engaged beneath the stop pawl 12 which has a finger 73 biased by a tension spring .'4 into position above the roller. The pawl is pivoted at 15 to a bracket 16 connected to the side member ll of the frame l5. The pawl is readily displaceable in clockwise direction by the roller 1! when the rock shaft 29 is oscillated counterclockwise during the inverting movement of the subframe 43 as already described. Obviously, however, as soon as the roller H passes beneath the pawl 12, the tension of spring 1 will bias the pawl to stop position above the roller H as illustrated.

The position of the axle rock shaft 29, wheel 36 and arm 46, illustrated in Fig. 3, is determined by stop pawl 18 which is pivoted at 19 to the bracket 16 and is movable on its pivot to and from stop position above the roller H of arm 40. This is the intermediate position of the wheel 36 with regard to the frame l5.

Wheel 35 is shown in Fig. 3 in its extreme upper position relative to frame [5. The arm 39 of its rock shaft 28 is engaged with one of the adjustable stop levers pivoted on the rock shaft 28 and adiustably positioned by an extension link which includes the screw-threaded barrel 8! and .screw 82, the screw having a crank 83 for its rotation and being fixed against axial displacement respecting bearing 84 carried by the support 85.

Each time the subframe is inverted, both of the .rock shafts will be adjusted automatically to the road positions shown in Fig. 2, due to engagement of the cam member 68 with the arms 69, 10, on the respective axle rock shafts as already described, Means is provided for manually releasin the respective rock shafts for clockwise rotation toward the intermediate or elevated positions as shown in Fig. 3, and such means is made to automatically arrest the movement of one of the rock shafts and its assocoated wheel in an intermediate position, and the other in its uppermost position in automatic timing with the respective positions of the subfrarne 43, and according to which plow bottom is positioned for operation. It will be apparent that if the left-hand plow bottom 4"! is in position for operation, the wheel 36 should be in an intermediate position and the wheel 35 in a raised positon. If, on the other hand, the plow bottom 46 is positioned for operation, the wheel 35 should be in an intermediate position and the wheel 36 in a raised position.

The shaft 63 already described is provided with a handlever 86 fast thereto. At its ends the shaft 63 carries upstanding arms 81, 88 (Fig. 4, Fig. 5). Intermediate the ends of these arms are apertures through which pass the links 89, 90, having at their forward ends nuts adjustably determinative of the position at which the arms 88 will act on the links. The respective links are connected at each side of the apparatus with the respectivexpawls-t 12 as: bestsh'own in Figs; 2

and 3; When'the upper en'd of lever 86 is pulled forwardly as. viewedzin Fig; 2; it will retract the respective pawls 1'2 fromthe path of the respective rollers ltonthe' arms 39, 4ll of the respective axle. ro'ch' shafts 28; 29, thereby allowing such arms andxr'ock shafts to oscillate clockwise under theweight'of the frame [5 andassociated parts.

Referring" again to Fig. 4;.it will be not'ed thateach of thearms tl and BS attached tQ the cross shaft 63""is: provided in its upper end with an elongatedislot'ilz. Through: these slots pass the links 93', 94 respectively, each provided at its end with a downwardly projectingfinger at' 95l Fig. 4 shows the rod 93 atlthe' lower end of its slot 92' in a position such that its finger 95 is engaged by the unslotted portion of lever 81. At the same time the link 94 is at the upper end of its slot 92 whereby its finger 95 will pass freely through slot 92 without being engaged by the lever 88. The links 93 and 9 3 are connected with the pawls 18 at opposite sides of the frame to control the position of such pawls. Intermediate their ends the links 93 and 94 are supported in bearings in the bell crank levers 96, 9?, respectively pivoted at 98, 99, and having their lower end portions depending in positions to be engaged by the cam members I00, H31, at diagonally opposite corners'of the subframe. The side of the subframe on which the plow bottom 48 is mounted will, at the time such plow bottom is elevated to its inoperative position as shown in Figs. 1 to 3, have its cam member I located inoperatively at the rear end of the subframe. The side of the subframe on which the plow bottom t? is mounted, such plow bottom being shown operative in Figs; 1 to 3, will have its cam member illl at the forward end of the sub-frame in a position of engagement with the bell crank lever 91. By virtue of such engagement, it has oscillated the bell crank lever 91 counterclockwise as viewed in Fig. 4 so that the link 95 is elevated to hold the finger 95 free of lever 88. Lever $6, on the other hand, not being engaged by cam member me, is in a position such that the link 93 which it supports isso lowered that its finger 95 is engaged by lever 81.

When the handlever 85 is pulled forwardly to retract the paw-ls "l2 and release the axle rock shafts 28, 29, from their road positions, the same rearward oscillation of the arms 81, 88 which re tracts pawls 12' will, in the indicated positions of the parts, retract the pawl 18 on the righthandside of the machine without retracting the paw-1 E8 on the left-hand side of the machine, the differential elfect on the respective Dawls being due to the operation of the cam member Elli on the bell crank lever 9'! as already described. Thus, the axle rock shafts, when released, will move clockwise to different positions, the arm 43 being arrested by pawl 18 at the left-hand side of the machine, While the corresponding pawl at the right-hand side of the machine is retracted to allow arm 39 to move into engagement with stop lever 88 as shown in Figure 3.

To hold the parts releasably in these positions, thehandlever 86 has a pawl I03 notched at I04 for engagement with support I05 and biased toward such engagement by tension spring I06. When the upper end of the lever 86 is pulled forwardly, the biasing spring H assures engagement of the notch me with support I05 to hold bothiof the pawls'lz and one or the other of 6"- thepawls 18 in their retracted positions. It will, of course; be u'nderstood that the question as to which of the pawls- 1*8- is retracted will depend upon which side of the subframe 43 is up permost and which of the cam members I00 01" I ll l is in operative relation tothe corresponding bell crank 'lever 9t or'sr.

When it is desired to reverse the apparatus preliminary to starting a new fur-row, it" is necessary to release-the several pawls 12, 1 3- atboth sides of the machine so that when the subframe t3 isinvertedl it willbe arrestedinaprope'rpos'i tion fora repetition of the cycle of movements above described! To efiectsuch release without any conscious-attention on the partof the operator, the rearwardly dire-cted'roller carrying arm of handle is previcled; shown in Fi s. 7 and 9, with a pin lil'l', and the pawl Hi3 is pro-- vided with a tail piece I03 depending therefrom which, asshown inFig. 8; immediately overliespin it when the pawl lllt i'sengaged with-support I85.- Fig. 9' shows how, when the handlever 62 is operated to effect release of subframe 43* for inversion; the pin l'flTen'gage's the tail piece Hit-"to lift the-pawl N33 to disengage its notched portionfrom the support member [05, therebyreleasinghandlever' Bfi'and allowing the latch pawl's' i2" and stop pawls 18" toresume theirnormal positions pursuant to their respective bias, as shown in Fig. 2.

Asalso'indicate'd in Fig. 2', therespective hand-'- levers '62, may be provided with appropriate forwardly projecting handles carried by support I89 in positions" convenient/for manipulation by' an operator'r'iding t'he'towing tractor;

. t will be apparent from the foregoing description of my improved control mechanisms that I have provided an improved lock controlling subframe'inv'ersion; that the release of the subframe for inversion inherently effectsthe resetting of the latches and stop pawls 1-2 and 1'8- at bothsides "oithe apparatus; that the subframe 43, in the courseof its inversion, automatically moves lllldfiXl-YQCK shafts andwheels positively to their respective road'positi'ons; and that the manipulation of handleve'r 86- then releases the axle rock shafts and wheels for movement to'plowing' positions at varying levels as determined automatically by the subf-rame in accordance with which plow bottom is positioned for Operation and which is supported ininactive position.

I' claim:

1. In a device of the character described, the combination with a frame and" an inver-- tible implement-carrying subi'rame engageable with'theground during inversion for raising'said" main frame, of wheels'forthe mainframe, piv= oted wheel supports upon which such wheels" are mounted and adjustable by oscillation of saidsupports to a plurality of positions respecting said frame, meansselectively operablefor lock-- ing sail.v wheel supportstosaid main frame for determining thepos-itions of oscillation of said supper-ts andtherefore the positi'o'ncf said wheels; and means carried in partby the main frame and in part by the invertible subtrame and em gage-able in the inversion of the subframe for automatically actuating said wheel position-determining me'ans.

2; Ina" device of the character described; the combination witha mainframe and an invertible implement carrying subframe' carried on the main frame and'engageablewith theeround during inversion for r'aising "sait:l' main" frame; of'

wheelsfor the mainframe; axlerock shafts for said wheels mounted in the main frame for adjustment to a plurality of wheel positions respecting the main frame, and means respectively carried by the invertible subframe and said axle shafts and engageable with each other in the inversion of the subframe for positively actuating said rock shafts in said direction toward one of said positions.

3. In a device of the character described, the combination with a main frame and an invertible implement-carrying subframe, of wheels for the main frame, axle rock shafts for said wheels mounted in the main frame for adjustment to a plurality of wheel positions respecting the main frame, and means respectively carried by the invertible subframe and said shafts and engageable in the inversion of the subframe for positively actuating said shafts toward one of said positions, manually releasable means for latching said shafts in the said positions to which they are positively actuated in the inversion of the subframe, said shafts being biased for movement toward other positions upon release of said latching means, a plurality of detents selectively adapted to define said other positions for the respective shafts and the wheels thereon, and means for selectively determining which of said detents will be operative with respect to each shaft, said subframe being provided with ofiset means for selectively actuating said last mentioned means in the inversion of said subframe whereby the respective positions to which the respective shafts and wheels move relative to the main frame upon release of said latching means will be predetermined by the position of the subframe.

4. In a device of the character described, the combination with a main frame and an implement-carrying subframe invertible on the main frame, of wheels and axles, axle carriers pivoted to the main frame for oscillation and adjustable to at least three positions wherein said axles and wheels are at different levels respecting the main frame, releasable latching means for securing the carriers in corresponding positions from which said carriers are biased to move toward respective other positions on release, stops determinative of the respective other positions of the carriers, means for the release of said latching means including means for selectively withdrawing one of said stops from the path of oscillation of one of said carriers, and means mounted in part on the invertible implementcarrying frame for determining, according to the position of inversion of such frame, the stop Withdrawn from the path of which particular carrier, whereby the relative positions of said wheels respecting said main frame will be dependent upon the inversion position of the implement-carrying frame.

5. In a device of the character described, the combination with a main frame and an invertible implement carrying subframe mounted thereon, of wheels for the support of the main frame, axle rock shafts for said wheels mounted for oscillation in the main frame and having wheel-carrying crank portions whereby to adjust the relative height of the wheels respecting the main frame, arms on said shafts oscillatory therewith, a series of two pawls and a stop in the path of oscillation of each of said arms, the first pawl of each series comprising means determining the maximum separation of said wheels and main frame and the stop determining the minimum separation thereof, means for retracting concurrently the first pawl of each series, said rock shafts being biased by the weight of said main frame to move said arms toward the respective stops upon the release of said first pawls, means for selectively moving one of the second pawls of the respective series from the path of its respective arm whereby to allow one of said arms to move to its stop while the other is arrested by the second pawl of its series, and means including parts relatively engageable in the inversion of the subframe and respectively supported by the subframe and the main frame for determining which of said series will have its second pawl retracted from the path of its respective arm, according to the position of inversion of the subframe.

6. The device of claim 5, in which the last mentioned means comprises a link connected with each of the second pawls and adjustable laterally between first and second positions, a support for each link movable to effect such lateral adjustment, cam means on the respective ends of said subframe respectively engageable with different supports according to the position of inversion of the subframe, whereby the link laterally displaced will depend on the subframe position, and actuating means for said links with which said links are selectively engageable and releasable depending upon their position of lateral displacement on their respective supports.

7. The device of claim 5, in further combination with means effective upon each inversion of the subframe for positively resetting said rock shafts with their respective arms in engagement with the first pawls of their respective series.

8. In a device of the character described, the combination with a main frame, of an invertible implement-carrying subframe mounted for step by step rotation on the main frame and provided at its left and right sides with relatively offset members, left and right supports pivotally mounted on the mainframe in positions to be alternatively engaged and displaced by said members according to the position of the subframe, wheels for the main frame, left and right axle rock shafts for said wheels in oscillatory connection with the main frame and by rocking of which said wheels are adjustable to at least three positions of vertical adjustment respecting the main frame, left and right arms connected respectively with the left and right rock shafts for movement therewith, a latch means releasably engageable with each of said arms for determining first positions of said rock shafts and wheels, a release member in operative connection with both of said latch means for concurrently releasing the arms, left and right retractible stops with which the left and right arms are respectively selectively engageable upon release by said latch means, connections for the retraction of the stops, and left and right selective couplings from said connections to said release member and operatively connected to be actuated between operative and inoperative positions by the left and right supports respectively whereby said connections will be selectively coupled to and released from coupling engagement with said release member according to the positions of the left and right offset members, and further left and right stop means with which the left and right arms are engageable when their respective stops are retracted as determined by the position of inversion of the subframe.

9. In a device of the character described, the combination with a main fram open at its rear, of a subframe rotatably mounted on the main frame for inversion and provided with 'implement- *carrying portions, axle rock shafts pivoted to the main frame at each sideof thesubframe and offset from the axis of subframe rotation, said axle rock shafts having'cran-ks and axles carried by the cranks, wheels mounted on the axles and movable with'their respective-rock shafts through a predeterminedseries of at least three positions of verticaladjustmentrespecting the main frame, arms carried by the respective rock shafts, and means carried by the subframe and engageable with the respective arms during a limited portion of the rotation of the subframe and disengageable'therewith during subsequent rotation because of the offset of the rock-shafts from the axis of subframe rotation, the engagement of said arms and subframe means being adapted in the course of each subframe inversion to move the rock shafts positively to predetermined positions of wheel adjustment respecting the main frame.

10. The device of claim 9, in further combination with meansfor rele'asably latching the rock shafts in the positions to which they are positively adjusted, releasing means for said latching means, stops for selectively determining second positions of the respective rock shafts upon release of said latching means, the respective rock shafts having members engageable with their respective stops,andmeans effective in eachposition of inversion'of the sub-frame for selectively coupling said latching means to a given stop for selectively retracting the selected stop to permit the rock shaft controlled thereby to move to a third position while the other rock shaft is arrested by its stop in a second position,

11. In a device of the character described, the combination with a main frame, of axle rock shafts journalled therein for oscillation through a predetermined range of positions and provided with cranked axles, wheels mounted on the axles for selective adjustment with said shafts between at least three positions with respect to said frame, a subframe invertibly mounted in said main frame, means for locking the subframe to the main frame in each position of subframe inversion, a stop arm connected with each rock shaft, stops in the path of oscillation of the respective arms and engageable thereby to determine selected arm positions, a plurality of said stops being retractible from the path of each arm, retracting means in operative connection with the first stop in the path of each arm for the simultaneous release of the respective arms, said rock shafts being biased for movement from the positions determined by said first stops upon release thereby, connections from the second retractible stop in the path of each arm provided with couplings selectively engageable with said retracting means, coupling-actuating members for each of said couplings determinative of coupling engagement between said connections and said retracting means, and cams at opposite sides of the invertible subframe and selectively engageable with the respective coupling-actuating means according to the position of subframe inversion for selectively effecting coupling engagement of one of said connections to said actuating means in one subframe position and the other of said connections to said actuating means in another of said subframe positions, together with third stops with which the respective arms are engageable when they pass their respective second stops through operation of said retracting means during engagement of said coupling means as "determined by the position of inversion of said subframe.

12. The device of claim 11, in which the first and second stopsin the path of each arm comprise pivoted 'dogs. v

13. The device of claim 11, in which the second stop in the path of each arm comprises a pivoted dog, the connecting means being a link inpivotal connection with the dog, and the coupling means comprising a lug on the end of the link disposed in an elongated aperture with which said release means is provided, said lug being engageable with or disengageable from said release means according to its position in the aperture as determined by one of said cams and a cam-operated coupling-actuating means. 14. In a device of the character described, the combination with a mainframe and an invertible implement-carrying subframe, of means for locking the subframe to the main frame against inversion, a release lever for said locking means, adjustable wheel supports provided with wheels for the main frame, means effective upon each inversion of the subframe for resetting the wheels in a predetermined position of adjustment of their respective supports with regard to the main frame, releasable latch means for holding the respective wheel supports in the positions to which they are adjusted, stops determining a plurality'of positions to which the respective supportsare movable upon release from said latch means, certain of said stops being retractible to permitsaid-supports to move to successive positions, means for releasing the latch means and 'for selectively retracting one of said supports, means carried in part by the sub-frame for determining which of said supports is retracted, nd means connected with said lever for resetting said latch means and the retracted support preliminary to inversion of the subframe.

15. In a turnover plow, the combination with a main frame and invertible subframe, of wheels for the main frame, carriers for said wheels movable respecting the main frame and by which the wheels are individually mounted for respective adjustment to determine the height of said main frame, said subframe being positioned to engage the ground during inversion for raising main frame, and means on said carriers and means on the sub-frame engageable, at such times as the main frame is raised to substantially its maximum height, with said means on said carriers for transmitting motion from said subframe to the respective carriers in the course of subframe inversion for positively adjusting such carriers toward their positions resulting in maximum height of said main frame in each subframe inversion.

16. In a turnover plow, the combination with a main frame and invertible subframe, of wheels for the main frame, axles for the wheels, axle carriers pivoted to the main frame for oscillation, stop means connected with the main frame and determinative of selected positions of oscillation of the carriers whereby to control the height of the main frame respecting said wheels, tripping means for retracting certain of said stop means, and means respectively mounted on the subframe and the main frame engageable in the inversion of the subframe for conditioning said tripping means for retracting a selected stop means for automatically varying the relative positions of said wheels relatively to the main frame in accordance with the position of the subframe, upon actuation of said tripping means.

17. In a device of the character described, the

combination with a main frame and an implement-carrying subfraine invertible on the main frame, of wheels and axles, axle carriers pivoted to the main frame for oscillation and adjustable to at least three positions wherein said axles and Wheels are at different levels respecting the main frame, releasable latchin means for securing the carriers in corresponding positions from which said carriers are biased to move toward respective other positions on release, stops determinative of the respective other positions of the carriers, means for the release of said latching means including means for selectively withdrawing one of said stops from the patch of oscillation of one of said carriers, means mounted in part on the invertible implement-carrying frame for determining, according to the position of inversion of such frame, the stop withdrawn from the path of which particular carrier, whereby the relative positions of said wheels respecting said main frame will be dependent upon the inversion position of the implement-carrying frame, and means for maintaining said means for the release of said latching means in released position to prevent inadvertent latching of said carriers.

18. In a device of the character described, the combination with a main frame and an implement-carrying subframe invertible on the main frame, of wheels and axles, axle carriers pivoted to the main frame for oscillation and adjustable to at least three positions wherein said axles and wheels are at different levels respecting the main frame, releasable latching means for securing the carriers in corresponding positions from which said carriers are biased to move toward respective other positions on release, stops determinative of the respective other positions of the carriers, means for the release of said latching means including means for selectively withdrawing one of said stops from the path of oscillation of one of said carriers, means mounted in part on the invertible implement-carrying frame for determining, according to the position of inversion of such frame, the stop withdrawn from the path of which particular carrier, whereby the relative p0- sitions of said wheels respecting said main frame will be dependent upon the inversion position of the implement-carrying frame, means for maintaining said means for the release of said latching means in released position to prevent inadvertent latching of said carriers, means for freeing said subframe for inversion and means on said freeing means for releasing said maintaining means when said subframe is freed for inversion.

JOHN M. MARKEL.

REFERENCES CITED The following references are of record in the

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