US2408361A - Rotary tiller - Google Patents

Description

Patented Oct. 1, 1.946

ROTARY TILLER John Peter Bagan, Portland, Oreg., assigner of one-third to Anthony R. Wanasek, Marshfield Oreg. Y

Application August 9, 1944, Serial No. 548,706

10 Claims.

This invention relates to a machine adapted for use for plowing or tillingthe soil, grading or levelling the ground, weeding, etc., and is more particularly concerned with the type of machine in which a spirally shaped cutter blade is rotated in contact with the earth surface to be worked, serving to cut, pick up, disintegrate and Vredeposit the surface layer of earth. Prior workers, recognizing the merits of such a machine have vmade many attempts to provide a practical embodiment thereof which is capable of operation by a relatively unskilled person under varying soil conditions. Many difficulties have been encountered and as a result no such machine has, up to the present time, attained general acceptance and widespread use. f e

A primary cause of the difficulties heretofore encountered in providing a practical machine of this sort has been the spiral cutter.

An object of my invention is to provide a spiral cutter which eliminates many of the difliculties heretofore encountered, such as the tendency of the machine to act as a conveyor, moving the earth laterally of the machine so as to produce ridges and furrows instead of a smooth flat tilled surface and the tendency `of the machine to moveV laterally. A further object of my inventionis to provide a simple, easily constructed, inexpensive, easily operated machine which is relatively free of parts likely to break or function improperly.

In general my machine consists of a simple frame carried on two wheels which supports the transverse rotary tiller and drive mechanism. Due to the fact that the rotary tiller of my invention is balanced so as to be relatively free of a tendency to move the earth laterally or itself to move laterally, it is unnecessary to provide special means, such as coulters, to hold theY machine in line or to provide special means to deposit the earth lifted by the spiral blades in a smooth layer..

A machine embodying my invention and illus- Atrative thereof is shown in the accompanying drawings, in which,

Fig. 1 is a top plan view of the machine,

Fig. 2 is an elevation of the rear of the machine,

Fig. 3 is an elevation of the left side of the machine, 1

Fig. 4 is an elevation of the right side of the machine showing the means for driving the rotary cutter,

Fig. 5 is a right end elevation of the rotary cutter, Y

(c1. en -41) Fig. 6 is a left end elevation of the rotaryY cutter,

Fig. '7 is a section on the line 1-1 of Fig. 2 and Figure 8 is a fragmentary rear view of the rotary cutter showing the overlapping of the blades. Y

Referring to the drawings, l is the platform of the machine which maybe made of wood or metal. Attached to and forming a part of this platform andV lending strength andrigidity to it are fthe angle irons 2 and 3. Angle iron 2, secured to the front edge of the platform, has one edge projecting downwardly several inches providing a baflie which catches earth thrown upwardly and forwardly by the rotary cutter. 'Ihe angle iron 3 is secured to the platformI parallel to but spaced from the rear edge thereof and has one edge projecting upwardly. The draw frame which is illustrated as a simple V consists of the side members 4 and 5 bolted to the platform through the angle irons Y2 and `i andattached at their front ends to the drawY plate 6. The ends of the platform carry the angle irons 1, I at the right endy and 8, 8 at the left end. Angle irons 1 and 1 and angle irons 8 and 8' are bolted together through the platform with the edges of angle irons 'land 8 projecting upwardly and the ends of angle irons I and 8' projecting downwardly providing vertical flat end surfaces to which are secured the end plates 9y and I0. End plate 9 carries the housing II and mounted on the housing II and on the end plate I0 are the vertically adjustable wheel supports I2 and I3 which, in the form illustrated, are designed to be operated .by means of a crank (not shown) on rods I2' and I3'. Vertical adjustment of the wheels I4 and I5 determines the depth of penetration of the rotary cutter into the ground.

Wheels I4 and I5 may be of any suitable type. The type illustrated having a relatively wide V-' shaped tread is preferred.

The housingr Il contains a suitable number of meshed pinions such as Athree (I6, I1 and I8), the uppermost of which, I6, rotates with the shaft I9 which extends through the bearing 20 carried by the plate 9 and the lowermost of which, I8, rotates with the shaft 22 which is keyed to the shaft 23 of the rotary cutter. The middle pinion I1 merely transmits motion from the pinion IB to the pinion I8.

The drive shaft I9 preferably is driven at two or more selected speeds through the transmission 25 from the propeller shaft 26. Propeller shaft 26 extends forwardly and is provided with .means (not shown) for attachment to a power source such as a tractor of known type which may be coupled to the draw plate 6 to move the machine and has a power take-off adapted to be coupled to the shaft 26 to rotate it. The propeller shaft preferably is provided with the two universal joints only one of which, 2l, is shown, the other being in front of the clutch 29 which is adapted to slip'when excessive forceis applied and thus to protect the rotary cutter and its drive mechanism against breakage,

a furrow or clear the way for the lower end .of the housing 3| is a dirt baffle hinged to the rear edge of the platform I and provided at its lower edge with the endwise adjustable levelling bar32.

The rotary cutter, as stated above, comprises the shaft 23, one end of which is keyed to and driven by the shaft 22. The other end is rotatably supported by the 'bearing 33 carried by the end plate |i3. The rotary cutter as illustrated in Figs. 5,k 6 and '7 comprises four 'balanced cutter sections a, b, c and d mounted on the shaft 23. It is to be understood, however, that the invention is not limited to four such sections since any number thereof, i. e. one, two, three, four or more of such sections may be employed depending upon the length of rotary cutter desired. The cutter sections are identical and therefore only one need be described in detail. The diameter and length of each cutter `section and the pitch of the spiral blades thereof may vary within wide limits depending 'upon the size of the machine and the kindof Work tobe done. For convenience I shall describe a cutter which I havefound to be well adaptedjfor plowing farmland of the types commonly used for growing corn, wheat and other grain crops, cotton, and Vegetables such as potatoes. This cutteris madel in sections about 'V14 inches long and -14 .inches in diameter and with four sections. Each section comprises four blade members in two groups, Two of the four blade members 3'4 and 'constituting one group start at a line around the shaft at an angle of 180'fr`om eachothe'r'and extend spirally 180 around the shaft with equal pitch. vThe other two blade members 3B and 37 constituting the other group start at a line `on'the shaftadjacent the ends of blades 34and 35 atan angle of"180 from each other but" at an angle of about 90 from'V the ends of blades :i4V andV 35 and extend around the shaft 180 at'the same pitch which is the reverse of the pitch of blades34 and 35. rIhe pitches of the blades are suchA that they tend to convey earth toward their adjacent ends as the cutter rotates in Contact with the earth to be treated, that is,'in the same angular direction as the wheels ld and l5. As stated, the diameter of the cutter, that is the distance between the opposite edges ofA two blades at the points of their intersection wth'a plane perpendicular to the axis of the cutter may be, say, 14inches and the length of each blade longitudinally of the shaft 7 inches, making the length of the cutter section 14 inches and the'pitch of the blade equal to its diameter, Y

It is preferable slightly to overlap the adjacent ends of blades 34| and 35 and blades 36 and 3'! as shown in Figure 8. The overlap, that is `the distance, longitudinally o f the shaft that blades 34 and 35 extend between blades 36 and 31 and vice versa may amountto an inch more or less. This overlapping is a desirable but optional feature. It has been found to relieve or distrib- 30 is a disc mount ed on the frame of the machine and set at an' angle and adapted to engage the ground andeut- 4 ute the strain on the free ends of the blades. The opposite ends of the blades are reinforced and supported by the flat knife members 38 and 39 which lie in planes perpendicular to the axis of the rotary cutter. Each blade 34, 35, 3E and 37 consists of a right helicoidal portion 40 adjacent andsecured to the axle of the cutter and an oblique helicoidal 'portion 4I extending outwardly from the right helicoidal portion 40. The relative widths of the portions 4) and 4I may vary within wide limits, that is, the Width of portion 410 may be equal to or greater than or less than the width of portion 4|, but generally for soil tillingfpurp'oses theportion 4| is somewhat wider than the portion'A in the ratio of 2 to l or greater. The angle between the two portions also may vary. Portion 4B is always perpendicularto the axis of the cutter, that is, it is always a right helicoid but the portion 4| may depart from the perpendicular to the axis of the cutter by an angle from say 10 to about-75. AAn angle of about 30 between -the line of intersection of the portion 4| with a plane which coincides with the axis of the cutter and a line in said plane which is perpendicular to the axis of the cutter generally is preferred for ordinary soil cultivation purposes. The two portions 40 and 4| of each blade may be integral or they -may be made separate from cach other andl welded, riveted or bolted together. The v blades may be cast or formed by working' sheet metal. The tips of the blades may be rounded as shown at' 42.

As stated, two', three or more cutter sections maybe mounted end to end on the same shaft or aX-le.- The adjacent blades of adjacent sections should then be set at an angle of to each other on the shaft. I

The described 'cutter' construction has many advantages over yrotary spiral cutters heretofore employed particularly-in that iteliminates end thrust and'tendency of the machine to swerve from a straight forward path and the corresponding tendency to transport earthlaterally of the machine land produce ridges'and valleys is eliminated. While therefissometendency to move the-earth to the middle of each section 3no objectionable .production` of 'a ridge has been found to occur inpractice. This probably is due tothe fact that' there are four blades operating on the ground near the'centerl of each section and to the further fact that each sectionis too sh0rt'.to produce -an objectionable. ridge.V Ihe short `sections also avoid `thel difficulty frequently encountered in plowing or tilling rough ground with a. relatively long. rotarylspiral cutter. The ground rarely is so rough orf-uneven that the end thrust ofthe .oppositelypitchedfblades of each sectionv do not encounter-enoughearth substantiallyvto balance each other. Moreover, the end thrust of anyzsingle pairlof blades is so small that the Inachineisv notcaused -to move laterally from its normal forward path. The. Gutter operates smoothly and generally maintains a uniform depth and consumes power quite uniformly except when it strikes some obstruction such as a root or stone and thus avoids excessive wear and Vbreakagefof the driving mechanism. The cutter generally remains lclear of earth and masses lofrvegetation such as `vines even under relatively adverse conditions such as spots of veryv wet ground and heavy growth of vines.

I have found it to be advantageous in some instances, although not essential, tov-includedn the machine a clod breaker consisting of a row of teeth similar to the teeth of a harrow mounted between the end plates 9 and l0 and extending downwardlyr and rearwardly in the principal path of the earth thrown rearwardly by the rotary cutter. I

It will be nted that I have not provided coulters or other means for guiding the machine, i. e. for resisting any tendency of the machine to shift sidewise due to end thrust of the rotary cutter.V The use of coulters is, of course, not excluded.y

I have shown the wheels I4 and I-5 as being adjustable vertically and have shown means for quickly or frequently adjusting the wheels when the machine is in motion. In many instances, however, I have found that very little wheel adjustment is necessary.- A given adjustment may Yserve for an entire eld being cultivated and may serve for all of the fields of a farm and for treatments (plowing, cultivating, etc.) at different seasons of the year. The provision of means for the adjustment of the wheels while the machine is in motion or the omission of all means for adjusting the wheels is, therefore, within the scope of my invention.

While I prefer to provide for operation of the rotary cutter at two or more speeds, it'is to be understood that it is within the scope of -my invention to omit' this feature as well as the use of the slip clutch for protection of the cutter when it strikes an obstruction. Modification of the frame of the machine, the use of different kinds of wheels and the provision of suitable bearings, universal joints and oiling and greasing means therefor are, of course, al1 within the skill of a mechanic andare within the purview of my invention.

I claim:

1. A rotary spiral tiller comprising a frame, supporting wheels and draft means, a spiral cutter mounted for rotation on the tion to engage the ground andr means for driving the rotary cutter, said rotary cutter comprising at least one section having a central shaft and at least one pair of spiral blades mounted thereon in predominately non-overlapping relationship to each other longitudinally of the shaft and oppositely pitched to move material toward each other when the cutter is rotated so that the forward edges thereof move downwardly as the cutter is moved forwardly, each blade eX- tending substantially 180 raround the shaft and the adjacent ends of the blades being equally spaced circumferentially of the shaft and the adjacent ends of blades of opposite pitch alternating with each other around the shaft.

2. A rotary tiller as defined in claim 1 in which the cutter section comprises a central shaft, a rst group of spiral blades of the same length and pitch mounted on the same portion of the shaft at equal angular distances from each other and a second group of blades cf the same length and pitch mounted on the adjacent portion of the shaft at equal angular distances from each other, the number of blades in each group being equal and each blade of the iirst group being equally angularly spaced between two adjacent blades of the second group and the pitches of the two groups of blades being opposed to each other so that as the cutter rotates in contact with earth each group of Iblades will move earth toward the other grou 3. A rotary tiller as defined in claim 1 in which the cutter section comprises a central sha-ft, a first group of spiral bladesV of the same length and pitch mounted on the same portion of the frame in a posi shaft `at equal angular distances from each other and a second group of blades of the same length and pitch mounted on theV adjacent portion of the shaft at equal angular distances from each other, the numbers of blades in each group being equal and each blade of the first group being equally angularly spaced between twoV adjacent blades of the second group and the pitches of the tworgroups of blades being opposed to each other so that the cutter rotates in contact with earth each group of blades will move earth toward the other group, and the adjacent ends of the blades of the two groups overlapping each other longitudinally of theshaft.

4. A rotary tiller as defined-in claim 1 in which A the cutter section comprises a central shaft, a first group of spiral blades of the same length and pitch mounted on the same portion of the shaft at equal angular distances from each other and a second group of blades of the same length and pitch mounted on `the adjacent portion of the shaft at .equal angular distances from each other, the numbers of blades in each group being equal and each blade of the first group being equally angularly spaced between two adjacent blades ofthe second group and the pitches of the two groups of Yblades being opposed to each other so that as the cutter rotates in contact with 'earth each group of blades will move earth toward the other group, each blade of each group of blades consistingof an inner right Ahelicoidal portion and an outer oblique helicoidal portion.

5. A rotary tiller as defined in claim 1 in which the cutter section comprises a central shaft, a rst group of spiral blades of the same length and pitch mounted on the same portion of the shaft at equal angular distances from each other and a second group of blades of the same length and pitch mounted on the adjacent portion of the shaft at equal angular distances from each other, the numbers of blades in each group being equal and each blade of the first group being equally angularly spaced between two adjacent and pitch mounted on the blades of the second group and the pitches of the two groups of blades being opposed to each other so that as the cutter rotates in contact with earth each group of blades will move earth toward the other group, and flat knife members perpendicular to the central shaft and overlying 'the remote ends of the blades.

6. A rotary tiller as defined in claim 1 in which the cutter section comprises a'central shaft, a first group of spiral blades of the same length and pitch mounted on the same portion of the shaft at equal angular distances from each other and a second group of blades of the same length adjacent portion of the shaft at equal angular distances from each other, the numbers of blades in each group being equal and each blade of the first group being equally angularly spaced between two adjacent blades of the second group and the pitches .of the two groups of blades being opposed to each other so that as the cutter rotates in contact with earth each group of blades will move earth toward the other group and the length of each blade longi- .tudinally of the shaft being about equal to its radial dimension.

'7. A rotary tiller comprising a frame, supportonfthe` same vportion ofthe shaft and equally spaced from each other, a second group of at least two spiral blades of the Asame length and pitch mounted on the adjacent portion of the shaft andequally spaced from each other, the numbers of blades in each group being equal and the blades of one group being of the same size but of equal and opposite pitch to the blades of the other group, the adjacent ends of each group ofv blades overlapping each other longitudinally of the shaft and -each blade of each group being equally spaced between two adjacent blades of the `other group, each blade of each group consisting of an inner right helicoidal portion and an outer oblique helicoidal portion.'

3; A rotary tiller as defined in claim 7 in which eachv section has four blades and the pitch of eachY blade is substantially equal to its outer diameter.

9; A spiral tiller as defined in claim'? in which each section has four blades each of which encompasses about 180of the circumference of the shaft and has a pitch substantially equal to its outer diameter.

10. A spiral tiller comprising a frame, supporting wheels and draft means, a spiral cutter mounted for rotation on said frame in Contact with the ground and means for rotating the same in such a direction that the forward edges of the blades of the cutter move downwardly as the tiller moves forwardly, said cutter comprising a horizontal shaft and a plurality of cutter sections each consisting of four spiral blades of equal length and pitch mounted on the shaft, the pitch of the blades being substantially equal to their outer diameters, eachgblade consisting of an in-A ner right helicoidal portionr and an outer oblique helicoidal portion, the latter being inclined at an acute angle with the shaft toward the direction that the spiral blades will move material when rotated in the direction deiined, a pair of said blades being of the. same pitch and equally spaced from each other on one portion of the shaft and a second pair of saidV blades being of the same pitch and equally spaced from each other on the adjacent portion of the shaft, the pitch of the rst pair of blades being opposite to that of the second two blades sothat each pair of blades tends to move material toward the other when the cutter is rotated in the direction specied, each blade being of such a pitch as to extend substantially 180 around the circumference of the shaft, the adjacent ends of each pair of blades overlapping each other along the shaft and being equally spaced around the shaft and the remote ends of each blade being supported by flat knife members lying in planes perpendicular to the shaft and covering said ends of the blades.

JOHN PETER BAGAN.

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