Abstract: A method for cultivating plantable soils, more particularly forest soils, by breaking-up and working-in plants and parts of plants lying upon the soil, for example leaves, needles, twigs and branches. To this end, a plurality of elements, flexible in all directions, tautened by centrifugal force, and secured to a shaft, are caused to rotate by the said shaft, the radius of rotation of the ends of the said elements being greater than the selected distance between the axis of rotation of the shaft and the surface of the ground. In order to be able to mechanically cultivate larger areas of substantially uneven and non-homogeneous forest soils, the horizontal axis of rotation of the shaft is also subjected to an oscillating pivoting motion about a vertical axis, the axis of rotation of the shaft being kept substantially radial to the pivot-axis and being moved in a circle which is parallel to the surface of the ground.

Abstract: A cutter for an impact-type cutting machine having a cutter shaft which is eccentrically provided on a drive shaft and is adapted to eccentrically rotate around the drive shaft axis. The cutter has an opening therein into which the cutter shaft is inserted with play therebetween. The hole in the cutter extends in the longitudinal direction of said cutter. A central portion of the hole substantially coincides with the center of gravity of the cutter.

Abstract: A control for an excavator controls the position of the bucket cutting edge to a desired depth accurately by a calibrating laser receiver mounted on the excavator stick member and passed through a stationary laser plane wherever the stick is moved into or out of a trench. Linear position encoders monitor the length that the actuating cylinders are extended and lookup tables convert the encoder outputs to angle representations for determining the positions of the laser receiver and the cutting edge. Other lookup tables are utilized to avoid time-consuming iterative calculation procedures to provide real-time digital process solutions of trigonometric functions. The apparatus includes a unique laser receiver comprising a plurality of linearly aligned photo receptors with associated circuitry for producing an output representative of the receptor illuminated or, if a group of receptors are illuminated, the centermost receptor illuminated.

Abstract: A position sensing apparatus and method useful for surveying, marking, and grading implement sensing and control is disclosed. The position sensing apparatus includes two laser reference stations, each of which projects a laser beam that periodically sweeps in a plane across the area to be surveyed. Each time a laser beam strikes the opposite reference station, a radio timing signal is broadcast by that reference station. The position sensing apparatus also includes a portable sensing station that comprises a laser beam receiver, a radio reciever, and a programmed computer. The planar position of the portable sensing station relative to the reference stations is computed by a triangulation technique based on the relative timing of detection of the laser beams by the laser beam receiver and the reception of the radio timing signals by the radio receiver. Elevation is determined according to the height at which one of the laser beams strikes the laser beam receiver.

Abstract: A rotary tilling device has a cutting device having a plurality of cutters each of which is rotatably mounted on a supporting member. The cutter has a vertical portion and a lateral portion at an end of the vertical portion and has edges on both sides of the vertical and lateral portions. The cutter is held by a stopper in a tilling position when rotated in a tilling direction, and is released in a grass cutting position when rotated in the opposite direction.

Abstract: A fully automated earthgrading machine and system is disclosed.

Abstract: A control for an excavator controls the position of the bucket cutting edge to a desired depth accurately by a calibrating laser receiver mounted on the excavator stick member and passed through a stationary laser plane wherever the stick is moved into or out of a trench. Linear position encoders monitor the length that the actuating cylinders are extended and lookup tables convert the encoder outputs to angle representations for determining the positions of the laser receiver and the cutting edge. Other lookup tables are utilized to avoid time-consuming iterative calculation procedures to provide real-time digital process solutions of trigonometric functions. The apparatus includes a unique laser receiver comprising a plurality of linearly aligned photo receptors with associated circuitry for producing an output representative of the receptor illuminated or, if a group of receptors are illuminated, the centermost receptor illuminated.

Abstract: A rotary tilling device has a cutting device having a plurality of cutters each of which is rotatably mounted by a bolt on a supporting member at a base end thereof. The cutter has a vertical portion and a lateral portion at an end of the vertical portion and has edges on both sides of the vertical and lateral portions. A stopper for receiving the cutter in a tilling position and a spring plate for resiliently holding the cutter in the tilling position are provided on the supporting member.

Abstract: A rotary tiling device has a cutting device having a plurality of cutters each of which is mounted on a supporting member at a base end thereof in such a manner that the cutter is rotatable about a first center. The cutter has a vertical portion and a lateral portion at an end of the vertical portion and has edges on both sides of the vertical and lateral portions. The base end has an arcuated periphery about a second center. The first center is offset from the second center, so that in grass cutting operation, the arcuated periphery is positioned in a position which is further outward than its position in the soil cutting operation.

Abstract: There is disclosed a plowing depth detecting system for a rotary plow adapted to detect an actual plowing depth on the basis of distance data with respect to the ground received from a distance sensor attached to the rotary plow which is vertically movably connected to a vehicle through a link mechanism. The distance sensor provides a microprocessor with distance data with respect to the ground rearwardly of the rotary plow. The microprocessor determines a value of actual plowing depth of the rotary plow on the basis of this distance data and a correction value according to a working condition of the rotary plow.

Abstract: A non-contacting range sensing and control device for controlling the position of a grading implement relative to a datum is disclosed. The device includes a non-contacting distance measuring device that periodically measures the separation distance between the distance measuring device and the datum. Also included is a reference circuit that defines consecutive first, second, and third intervals for comparison to the separation distance, and a comparison circuit that periodically compares the intervals to the separation distance, and generates a positive error signal if the separation distance is within the limits of the first interval, generates no error signal if the separation distance is within the limits of the second interval, and generates a negative error signal if the separation distance is within the limits of the third interval.

Abstract: A system for guiding a vehicle along a pre-determined rectilinear path which comprises a vehicle having a laser fixed thereon so as to direct a laser beam along the direction of motion of the vehicle towards a target carrying beam reversing means positioned on the vehicle path so as to direct the beam back to the vehicle.

Abstract: An agricultural implement for clearing a field of crop residue after harvest is attached to the linkage of a tractor and serves to cut and shred stalks of plants planted in two parallel rows. It comprises two sheave-shaped rollers on a common axle serving to crush the stalks and to flatten them onto the ground, and two flail-type fast-rotating shredders whose cutter bars cut and shred the stalks pressed on the ground by the rollers, while slightly penetrating in to the soil surface and cutting the upper root portions as well. Each shredder consists of a drum with pivotally attached cutter bars; both shredders are mounted on a horizontal shaft which is driven by the tractor power-take-off through a gear. A casing collects the shredded particles and spreads them on the ground behind the implement.

Abstract: The invention comprises a crank-linkage arrangement for a hydraulic servo valve, used on a road planer, to give the valve more sensitivity. It has a valve-operating crank coupled to a leverage-type linkage. The linkage responds to movements of a ground-engaging ski, which tracks the road surface, by displacing a same degree as does the ski, but by effecting a greater displacement of the crank. Limit stops on either sides of a limb of the linkage prevent any damaging overtravel of the crank.

Abstract: A blade cross slope sensor includes a first T-member having a stem mounted on the drawbar of a road grader for rotation about a first axis parallel to the axis about which the blade rotates and being coupled to the blade for rotation through the same angle. A yoke is pivotal on the arms of the T-member and a second T-member is pivotal on the yoke about a second axis perpendicular to the first axis. A scissors assembly has a first portion mounted on the grader main frame for pivotal movement about a third axis parallel to the direction that the grader travels and a second portion coupled to the first portion for pivotal movement about a fourth axis parallel to the third axis. The second scissors portion is also pivotally connected to the arms of the second T-member which defines the true cross slope of the blade.

Abstract: A blade control device comprises a change-over switch for providing light receiving position deviation signal sent out from a light receiving device into a light receiving device control system as a command value, and a device for measuring the change in the height of the light receiving device, whereby a topographic survey is conducted based on the height change of the light receiving device.The blade control device may further be provided with a second change-over switch for providing the command value outputted from a manual command value setter during a manual operation into the light receiving device control system, whereby returning the blade to a previous position is carried out in accordance with the operation of the second change-over switch.

Abstract: A seated-operator type tractor has a vehicle proper (1), equipped rearwardly thereof with a link mechanism (6) and a scraper (9) for ground-leveling. The vehicle (1) is further provided with: a position-controlling mechanism (34) for controlling up-and-down position of the scraper (9); an automatic control mechanism for maintaining the scraper (9) in its left-and-right horizontal posture, by a sensor (50) therefor; a controlling valve (24) for controlling blade-angle adjustment of the scraper (9); and a manual switch (47) disposed near at hand of the seated operator, for shifting over the vehicle (24).

Abstract: A land leveling device having a frame supported on wheels for earth traversing movement forwardly thereof; a first pair of blades borne by the frame in rearwardly convergent oblique relation to each other; a second pair of blades borne by the frame rearwardly of the first pair in rearwardly divergent oblique relation to each other; and means for deploying the frame in a substantially horizontal attitude substantially continuously during said earth traversing movement.

Abstract: The control is mounted on the turntable of a conventional motor grader or similar scraper, in a direction parallel to an axis through the points of attachment to the turntable of the rods of two rams which control the angle of the blade of the scraper to the horizontal. The control is used to hold the blade angle at a first angle when the scraper is moving in one direction and at a second angle when moving in another direction. In the control are two vials mounted side-by-side and adjustable by a motor to be centered at the aforesaid first and second angles. A control box on the cab enables the operator to selectively adjust the electric current of the device to respond to one vial or the other depending on the direction of movement of the scraper. If the blade is off the desired angle, a signal from the vial actuates a hydraulic valve control to energize one or both rams to raise or lower and thus restore the blade to the preselected angle.

Abstract: An integrated shredder/plow combination for reducing trash to facilitate its being mixed with the soil by the action of the trailing plow portion of the combination is disclosed. The shredder portion includes a unique arched structure positioned above a housing enclosing the shredder's cutting blades which permits the plow's drag to be transmitted directly to the tractor hitch so as to bypass the shredder assembly. The shredder assembly is thus not subjected to the large longitudinal forces associated with plowing operations as well as the high side loading encountered during turns and as a result of ground countour. This prolongs shredder operating lifetime and increases its reliability. By positioning the plow assembly immediately aft of the shredder mechanism, the cut-up vegetation, or trash, is more effectively turned under as it is in an agitated, suspended condition when it encounters the burying action of the trailing plow assemblies.

Abstract: A path indicating apparatus for indicating a path so that a moving vehicle movable in the horizontal and vertical directions, such as an aircraft, may move along such a predetermined path. The predetermined path is defined as an intersecting line of two scanning planes which are formed by scanning signals having a narrow beam width in a horizontal plane and a vertical plane, respectively. The vehicle is provided with a plurality of detectors arranged in the horizontal and vertical directions for detecting the signals being scanned in the horizontal and vertical planes, respectively, so that the detectors arranged in the vertical and horizontal directions may detect deviation of the vehicle in the horizontal and vertical planes, respectively. The vehicle is responsive to the detected signals from the respective detectors to determine the moving direction to be taken by the vehicle so that the vehicle may move along the path and the vehicle is steered responsive to the determined direction outputs.

Abstract: Disclosed is an electro-optical and microcomputer based method and apparatus for automatically guiding tractors and other farm machinery for the purpose of automatic crop planting, tending and harvesting. Also disclosed are means for automatic picking, excavating and other off-road uses in relatively confined areas.

Abstract: A method of resurfacing a road or the like wherein existing surface profile is first measured as a function of distance over the road surface. A desired profile is then identified as a function of measured road profile by simulating travel of a vehicle over the road surface and observing the quality of vehicle ride and/or pavement dynamic load while the spatial wavelength characteristics of measured profile are progressively attenuated. When ride quality and/or dynamic load of desired preselected standard is obtained, a resurface control signal is obtained as a conjoint function of distance along the road surface and the difference between measured profile and spatially attenuated profile. Road resurfacing equipment is also disclosed for selective removal of pavement surface material or selective deposition of paving material as a function of the control signal so obtained to achieve the desired resurfaced road profile.

Abstract: An earth working machine having an earth shaping blade (30) employs a control system for maintaining the blade (30) at a desired slope relative to a reference grade irrespective of lateral movement of the blade (30) or deflection of front and rear frame sections (15, 18). A ground engaging trailing wheel (96) mounted at the rear of the blade (30) senses rotation of the blade (30) relative to the direction of machine travel resulting from rotation or lateral shifting of the blade (30) and operates a potentiometer (124) to produce a control signal proportional to the magnitude of blade rotation. A first pair of accelerometers (128, 130) mounted on the blade (30) for rotation by the trailing wheel (96) produces blade controlling signals respectively corresponding to the change in slope and pitch of the blade (30) relative to the front frame section (15) of the machine.

Abstract: Apparatus for breaking rock found in soil, such as in a field used for farming, includes a hood-like housing. A work shaft and a drum are positioned under the hood with the work shaft preceding the drum in the normal direction of movement of the apparatus. Flail-like parts are located on the outer surface of the work shaft and travel along a circular path. Prongs are provided on the drum and also move around a circular path. The circular path of the prongs is located lower than the circular path of the flail-like parts and at their closest point the circular paths are approximately tangent to one another where rock or other material is transferred from the prongs to the flail-like parts.

Abstract: In combination with a conventional laser beam control system for controlling an earth scraping and storing apparatus, such as a box blade for example, for leveling terrain, an improvement detecting when the box blade is full and overflowing is imminent and sensing the level of the box blade relative to the ground. The improvement overrides the functions of the conventional laser beam controls, when desirable, whereby overfilling and bogging down of the box blade is prevented and whereby rough terrain is readily and effectively leveled.

Abstract: Method and apparatus for planting seeds in a field. An anti-cohesion liquid chemical is injected at 30 to 50 p.s.i. into a narrow ribbon of soil, no more than two inches wide and two inches deep. Immediately thereafter, the soil ribbon is vigorously agitated at 900 to 2000 r.p.m. to insure coating of all of the soil particles with the chemical to a depth below that at which the seed is to be planted. The seeds are then placed at precise locations within and covered by the treated soil, and the soil over them is firmed.

Abstract: A surface grading device adapted to be towed over a surface to be graded, capable of self adjustment in accordance with a pre-established signal such as a laser beam, capable of grading cross sloping surfaces, capable of minimizing blade deflection caused by carrier wheels hitting a flaw in grade, and adaptable for highway towing along a single lane of a highway.

Abstract: A mobile grading machine and method with a scraper structure including a grading blade supported by caster wheels trailing therebehind. A trailing connection is disposed between the scraper structure and the caster wheels in fixed lateral relation relative to the ends of the blade. A fixed towing connection is carried at a leading portion of the scraper adapted to be coupled to a towing assembly of a tractor in a manner so as to support the grading structure for terrain following movement. A laser sensor or receiver is carried by the grading machine for raising and lowering the grading blade as the receiver falls and rises in traveling across a field. The grading blade and receiver are sufficiently closely spaced longitudinally so as to cause the receiver to detect a change in the surface of the terrain substantially coincident with the arrival of the blade at the detected change.

Abstract: A backhoe includes a computer capable of automatically controlling the depth or lowermost point of the backhoe bucket. The computer is programmable to provide level operation of the backhoe, will have preset common depths and programmable depths, and further include an automatic empty and return cycle, and to maintain a given level or slope of a desired ditch. Special resistors are positioned at all of the pivot points of the backhoe to act as sensors for relaying information to the computer. The output of the computer controls hydraulic valves which, in turn, operate the outriggers, boom, crowd and bucket of the backhoe assembly.

Abstract: An automatic control device for an earth working equipment is directed to remove influence of acceleration on an inclinometer mounted on a vehicle body and thereby to effect an accurate blade control. An acceleration compensation arithmatic circuit receives outputs of a pair of inclinometer and removes an acceleration component by performing integration twice. This circuit is also designed to remove an integration error. Further, according to the invention, a Doppler radar system and an engine speed/throttle opening system are employed for detection of overload applied to the blade so that one of the detection systems which is most suitable for an actual work can be selected. Furthermore, the device includes both blade height controllers and tilt controllers and performs the two control operations most effectively.

Abstract: A motor powered lawn edger is converted to a lawn cultivator, a snow blower, or an ice chipper by removal of the lawn edging blade and its housing, and substitution therefor of a cultivating, blowing or chipping blade and an appropriate housing.

Abstract: A beam receiver secured to an upper portion of a blade of an earth working equipment can rotate in a horizontal plane and move in a vertical direction and, accordingly, can catch a laser beam from a beam projector regardless of a direction of the equipment. When the beam has been deviated out of the beam receiver, the direction of the deviation is detected so that the beam can be received by the beam receiver again. The height of the beam receiver relative to the blade can be adjusted and the level of the blade can thereby be controlled very accurately.

Abstract: A cultivating machine has groups of soil working tines that are mounted on an elongated support that is driven to rotate about a horizontal axis. The tines are mounted in spaced apart groups and guide members converge at the rear of the groups to form ridges of worked soil. Each group includes tine units that are formed by opposing bracket portions clamped to the support. Strikers can be mounted on the support between groups of tines and the strikers are pivotable about respective horizontal axes spaced from the support's axis of rotation. The strikers are positioned to excise crop leaves or emerged growth on the ridges. Hoods and a grating ensure that the top layer of worked soil is free of debris. Screening plates having obliquely upwardly and inwardly inclined inner edges are located at the lower, front, outer corners of the hood to prevent the rearwardly adjacent time groups from displacing soil too far laterally.

Abstract: A laser beam level control system for an earth-moving machine is provided with an automatic override function to temporarily block blade-down signals and raise the blade when lowering it or leaving it at its previous height would increase the force required to drive the machine across the ground above a preselected value which does not exceed the tractional force capability of the machine's drive wheels or exceed the machine's available horsepower.

Abstract: A rotatable flail-type agricultural implement is disclosed which includes a central axle and a plurality of radially and circumferentially spaced, flexible, hammer-supporting chains presenting a plurality of ground crop-engaging flails upon rotation of the axle. The axle is preferably composed of a pair of elongated, telescopically interfitted sections, at least one of which is shiftable, such that the effective width of the implement can be varied to accommodate different crop row spacings. In addition, the axle sections include complemental, spiral key and keyway structure for maintaining the flexible hammer chains in a substantially constant, spaced relationship to the central axle, irrespective of variances in the axle length.

Abstract: A hammer plow is provided with a series of disks spaced along and rotatable with a sleeve that turns about an axle on a number of bearings located therebetween. Each of the disks has a plurality of hammers rotatably attached thereto, which are free to rotate in complete circles. The rotatable length of the hammers is shorter than the distance from the points of attachment to the disks to the sleeves or spacers therebetween. A hammer striking an obstruction in ground to be plowed will not break, but is free to counter-rotate relative to the disk to which it is attached. Numerous agricultural and construction grading operations can be performed in a single pass of the device over ground to be plowed.

Abstract: An attitude control system for controlling a pitch angle in relation to a horizontal pitch reference in systems wherein the components of pitch angle and horizontal pitch combine to determine a parallel path of travel with respect to a horizontal reference plane. The attitude control system consists of a slope sensor for measuring and compensating for pitch attitude changes in conjunction with a grade control system for monitoring horizontal reference. The present attitude control system is applicable to trenching machines whereby soil conditions affecting pitch angle are compensated in conjunction with horizontal pitch to control a predetermined grade or the pitch angle can be utilized alone to control slope of an excavation line.

Abstract: An improved guidance device for use with an earthworking machine, more especially a drain tile laying machine, comprising a earthworking element mounted about a pivot connection. This guidance device comprises a signal emitter and two signal receivers mounted on the earthworking element of the machine. The two signal receivers are mounted on the element in a longitudinal spaced apart relation, so as to distinguish between a depth change or an attitude change in the element. The guidance device also comprises operating means including an electronic control circuit and an hydraulic operating circuit for adjusting the attitude or depth of the element depending on the indication given by the signal receivers.

Abstract: Flail members are mounted on a rotatable drum by providing a plurality of angularly spaced rows of longitudinally spaced openings in the drum. A tube rectangular in cross section extends through each opening and is secured rigidly to the drum for receiving a clevis with a sliding fit with the inner end of a flail member being attached to the clevis. Transverse openings through the walls of the tube and the legs of the clevis are aligned with each other in a direction longitudinally of the drum for receiving a rod which extends inwardly of the drum and longitudinally thereof. Detachable means locks the rod in place.

Abstract: Apparatus including a digger for digging a trench to a predetermined level which is maintained by control apparatus responsive to a laser beam plane. The earth removed by the digger is directed into screening apparatus, and at least some of the fine particles therefrom are spread over the bottom of the trench to a predetermined depth. A roller unit follows the digger and presses a system of channels in the trench bottom. The coarser particles from the screening apparatus are then spread over the trench bottom and the channels. If desired, the apparatus may include means for directing a sealant over the surfaces of the channels before the coarse particles are directed thereover.

Abstract: A delimber attachment for a tractor comprises an elongate drum mounted transversely and rotatably within a downwardly opening enlosure. The drum has a plurality of chains connected at one thereto. A frame extends forwardly from the enclosure. A hinge connector near a forward end of the frame hingedly connects the delimber to the tractor for upward and downward pivoting. A cable receiver is located near a top portion of the enclosure. A hydraulic damping cylinder is connected near a first end to the delimber and extends upwardly and forwardly therefrom. The cylinder has a clasp near a second end of the cylinder for connecting the cylinder to the tractor above the hinge connector.

Abstract: In a slope control apparatus for the working tool of a motor grader or other earth working machine, the slope sensor used for controlling the slope of the tool is mounted on a revolving platform the attitude of which is corrected by a factor related to the rotational angle of the tool about a vertical axis and also related to the angle of the tool with respect to the line of flight axis of the machine. The apparatus is mounted in a fashion to allow the tool to be swung to a vertical position without damage to said apparatus.

Abstract: A laser beam level control system for an earth-moving machine is provided with an automatic override function to temporarily block blade-down signals and raise the blade when lowering it or leaving it at its previous height would increase the force required to drive the machine across the ground above a preselected value which does not exceed the tractional force capability of the machine's drive wheels or exceed the machine's available horsepower.

Abstract: The flail device comprises a rotatable drum, a series of circumferentially spaced channels extending lengthwise of the drum, support means in each channels, a rod received in each support means, and flexible flails attached to each support means at longitudinally spaced intervals thereon; each flail consists of a length of chain links and the rod in each support means passes through the end link of the flails which are extendible under centrifugal force when the drum is rotating.

Abstract: A controlling apparatus for bulldozer blade in which the control is carried out automatically or manually.The apparatus comprises an electromagnetic valve for controlling a cylinder of the bulldozer blade, a switch for changing the control of the bulldozer blade automatically or manually, a safety relay connected with said switch, the safety relay being adapted to be actuated only when the switch is maintained in a manual operating position, and a load reading relay adapted to be actuated by a signal fed from a load detecting circuit for supplying a signal to one of the solenoids of the electromagnetic valve.

Abstract: A tool-carrying vehicle, such as a road grader, is provided with an apparatus for maintaining a predetermined distance between its blade or other tool and a laser reference plane generated by a rotating laser beam. The apparatus includes a detector housing supported on a mounting extending upwardly from the blade, a detector support frame on the housing, a laser reference plane detector on the support frame, and electrical control circuitry. The mounting is movable to permit moving the detector housing relative to the vehicle in response to tool movement.The laser reference plane detector has first and second spaced apart laser beam detecting arrays. The detector may be provided with upper and lower movable carriages with one of the arrays positioned on each carriage, permitting the carriages to converge and diverge to vary the distance separating the detecting arrays and thereby control the degree of accuracy required of the tool.

Abstract: In a civil machine comprising a working tool provided on a vehicle with a travelling mechanism and a drive therefor, an automatic control system comprises a stroke detector for detecting the amount of stroke of a lifting cylinder operating to move the working tool up and down, an inclination angle detector for detecting the inclination angle of the vehicle, an arithmetic unit for obtaining data representative of the height of the working tool from the detection signals of the two detectors, and a control for operating the lifting cylinder by using the data to control the position of the working tool with high accuracy.

Abstract: An apparatus mounting on the main frame of a motorgrader for controlling grading and sloping of road shoulders and previously subgraded surfaces having a resilient suspension system for the moldboard depending from the main frame of the grader which is laterally spaced from the point of application of a control load by a universally-connected, double-acting hydraulic jack attached thereto; said moldboard being lifted against said resilient support relative to the main frame of the grader for grade control by a shoe, wheel or ski, which is mounted adjacent the one end thereof and arranged for sliding along a roadway or other previously graded surface as a horizontal reference, and tilted relative to the main frame for slope control by manipulation of the double-acting hydraulic jack controlled by a feedback controller which measures the error in actual moldboard tilt and compares it to a fixed vertical reference as determined by a pendulous sensor and corrects the same in establishing the desired slope to the

Abstract: A cultivating machine has tines mounted on an elongated horizontal support that is driven to move the tines forwardly through the soil towards the normal direction of travel. The tines are in groups along the length of the support and each group has a number of pairs of opposing units. Each unit includes bracket portions having two rims and a tine is fastened to each rim. Opposing portions are bolted together to form a whole bracket that mounts four tines around the support. Each tine is a strip-shaped member that is hook-like in configuration with an inner straight portion and an outer soil working portion having a pointed tip. The inner portion has a series of holes along its length which can be releasably fastened to a respective rim in any one of a plurality of positions that change the working length of the tine. A front hood partially surrounds the tines and support and a rod grating is positioned at the rear of the tines. A rear hood is connected to the machine and located behind the grating.