US3216508A

US3216508A - Rotary spading machine

Info

Publication number: US3216508A
Application number: US299739A
Authority: US
Inventors: Horowitz Alexandre
Original assignee: ONTWIKKELINGMAATSCHAPPIJ MULTINORM NV
Current assignee: ONTWIKKELINGMAATSCHAPPIJ MULTINORM NV
Priority date: 1963-08-05
Filing date: 1963-08-05
Publication date: 1965-11-09
Anticipated expiration: 1982-11-09

Description

Nov. 9, 1965 A. HOROWITZ ROTARY SPADING MACHINE '7 Sheets-Sheet 1 Filed Aug. 5, 1963 a confac/ c/rc/e b=9enerafing0hcle c mva/uie c/rc/e INVENTOR ALEXANDRE HOROW/TZ ATToRNEYs Nov. 9, 1965 A. HOROWlTZ 3,216,508

ROTARY SPADING MACHINE Filed Aug. 5, 1963 7 Sheets-Sheet 2 a comacf circle b generating circle Fig. 6A

hypofhefic surface over which ihe circle; rolls wii'houf Slip.

F ig.6B

INVENTOR A LEXANDRE HOROW/ 7'Z ATTORNEY5 Nov. 9, 1965 A. HOROWITZ ROTARY SPADING MACHINE 7 Sheets-Sheet 3 Filed Aug. 5, 1963 INVENTOR ALEXA NDRE HOROW/ 7'Z ATTORNEY5 Nov. 9, 1965 A. HOROWlTZ 3,216,508

ROTARY SPADING MACHINE Filed Aug. 5, 1963 '7 Sheets-Sheet 4 I I I 2111111111 ALEXANDRE' HOROW/TZ ATTORNEYS 7 Sheets-Sheet 5 INVENTOR ALEXANDRE HOROW/TZ A. HOROWITZ ROTARY SPADING MACHINE Nov. 9, 1965 Filed Aug. 5, 1963 ATTORNEYS Nov. 9, 1965 A. HOROWITZ 3,216,508

ROTARY SPADING MACHINE Filed Aug. 5, 1965 7 Sheets-Sheet 6 Fig. 2/

Fig. 20

INVENTOR ALEXANDFE HOROW/T Z lax/Why ATTORNEYS Nov. 9, 1965 A. HOROWITZ 3,216,508

ROTARY SPADING MACHINE Filed Aug. 5, 1963 7 Sheets-Sheet 7 INVENTOR ALEX/ANDRE HOROW/TZ WWW/W ATTORNEY5 United States Patent Ofiice 3,216,508 Patented Nov. 9, 1965 3,216,508 ROTARY SPADING MACE Alexandre Horowitz, Eindhoven, Noord Brabant, Netherlands, assignor to N.V. Outwikkelirigmaatschappij Multinor'm, Amersfoort, Netherlands, a corporation of the Kingdom of the Netherlands Filed Aug. 5, 1963, Ser. No. 299,739 14 Claims. (Cl. 17295) The present application is a continuation-in-part of the copending patent application filed November 19, 1954, having the Serial No. 470,086, by the same named inventor and issued on February 4, 1964, as Patent No. 3,120,279.

The present invention relates to a machine for cultivating the soil, more particularly, to a rotary spading machine for simulating the manual spading and turning over of the soil.

It has long been known that from an agricultural point of view spading of the soil to dig up lumps of earth and turn these lumps over or on their sides is the best possible Way of preparing soil for cultivation. However, it is readily apparent that hand spading of the soil is impractical in cultivating large areas since a considerable amount of labor and time would be required. I

When preparing soil for cultivation by spading, the lumps of soil should be dug up and then turned over through an angle of at least 90 prior to depositing back on the ground. In this position, the soil will be exposed to the atmosphere and the weeds and other growths in the top of the lumps of soil will be buried so that this plant material will be killed.

The conventional apparatus for preparing the soil for cultivation consisted of the plowshare which was pulled through the soil in order to plow the soil and turn the soil over. The use of a plowshare has several disadvantages which may be listed as follows:

(1) A substantial amount of power is necessary to pull the plowshare through the soil.

(2) When slippery soil is being plowed, the tractor which is conventionally used to pull the plowshare will slide over the soil due to the heavy resistance of the plowshare in moving through the soil.

(3) The plowshare is unable to adequately prepare the soil for cultivation from an agricultural point of view.

This inadequate preparation will be apparent by pointing out that in plowing heavy clay soil long strips of the soil are wholly or partially turned. The soil, however, is not broken up into desired lumps of soil. Thus, instead of the desired lumps of soil, one merely has long strips of soil in the cultivated ground.

Another aspect of inadequately preparing the soil for cultivation is that the sliding movement of the plowshare on the bottom of the furrow may clog up the bottom of the furrow so as to hinder the penetration of the bottom of the furrow by the roots of the plants. Further, the clogging of the bottom of the furrow will hamper the drainage or absorption of rain water so that during heavy rainfalls polls of water will accumulate upon the plowed field. Prior to plowing of the soil, all of the water falling upon the soil will be absorbed therein so that there is 100% penetration of the water in unplowed soil. In contrast thereto, there may be only a 5% penetration of the water in the furrows of plowed ground when the bottoms of the furrows have been clogged by the plowshare.

As it became desirable to cultivate larger areas of land attempts were made to devise apparatus which would replace the conventional hand tilling of the soil. Such forms of appartus were essentially structures attempting to simulate manual spading of the soil. One form of an early cultivator comprised a drum-like member which had a plurality of curved digging blades extending outwardly from the periphery thereof. This drum-like cultivator was then pullled over the ground by horses or a tractor, and the digging blades purported to dig up and turn over the lumps of soil in a manner similar to that accomplished by hand spading of the soil. The rolling movement of the drum-like member over the ground enabled the substantially involute shaped digging blades to penetrate into the ground and after passing the deepest point of penetration to lift out of the ground a lump of earth. The size of the lump of earth depended upon the depth to which the digging blades penetrated the soil.

When merely dragging the drum-like cultivators over the ground, it was unexpectedly found that high traction forces were necessary to pull these cultivators during the plowing operation. These traction forces were even greater than those required to pull a plowshare through the soil when soil adhered to the plowshare. These high traction forces were due to the following:

(1) Friction between the convex surfaces of the digging blades and the undug soil.

(2) The forward component of force exerted against the digging blade by the soil as the cultivator was pulled over the ground.

The friction between the digging blade and the undug soil occurred as the digging blade was penetrating into the soil. This friction was substantial, particularly when attempting to plow heavy or wet clay soils.

With respect to the forward component of force, it is apparent that by pulling such a drum-like cultivator over the ground the rolling movement of the digging blade Wheel or drum is obtained by means of reaction forces exercised by the ground upon the leading convex surfaces of the digging blades which are in contact with the undug soil. As these digging blades penetrate into the ground, their convex surfaces slide along the undug soil during the transmission of the pulling or traction forces to produce a slow rotation of the digging blade drum. It is therefore apparent that a considerable amount of friction must be overcome during the penetrating movements of each digging blade. v I

As a result, these previously devised drum-like cultivators could be used only in light sandy soil. When attempting to plow wet clay, the weight of the cultivators had to be greatly increased so that the blades could penetrate into the soil. The addition of this weight, however, further increased the traction force necessary to pull the drum-like cultivator and the cultivator tended to compress the soil, thus in turn rendering more difiicult the penetration of the soil by the digging blades.

It is therefore the principal object of the present invention to provide a novel and improved cultivator for tilling the soil. k

It is another object of the present invention to provide a rotary spading machine which digs up lumps of soil and then deposits the lumps of soil upon the ground to simulate manual spading of the soil. I

It is a further object of the present invention to provide a rotary spading wheel with improved structure for pivoting digging blades in a predetermined manner.

It is a further object of the present invention to-provide a rotary spading machine which can be particularly adapted for the digging of ditches.

The present invention discloses a cultivator which is a considerable improvement over the drum-like cultivators previously known and solves the foregoing agricultural problems. The present cultivator essentially incorporates two measures which overcome the disadvantages of the prior art Cultivators. One feature of the present cultivator is the positive driving of the digging blade wheel and not merely pulling the cultivator over the ground so that the rotational movement of the digging blade wheel is no longer obtained by means of the reaction forces upon the leading convex surfaces of the blades by the ground. This measure in itself considerably reduced the power necessary to move the cultivator over the ground. The second feature resides in rotatably driving the digging blade wheel at such a speed relationship so that the rotary speed of the digging blade wheel is somewhat greater than would correspond with the rotary speed obtained when the digging blade wheel normally rolls over the ground.

The present cultivator essentially comprises a frame having one or more supporting wheels at one end thereof and at least one supporting member at another end thereof for controlling the operational depth. A digging blade wheel having a hub with a plurality of curved digging blades mounted thereon is rotatably mounted on a shaft carried by the frame. A power source comprising a motor is drivingly connected through a gear transmission to the digging blade wheel and is also connected to the supporting wheels of the frame. The gear transmission is constructed so as to drive the digging blade wheel at a particular speed relationship with respect to the speed of the frame over the ground surface.

Each of the digging blades is so shaped that a cross section of each blade in any plane perpendicular to the central axis of the digging blade wheel comprises an involute generated in the direction of rotation of the digging blade wheel. In addition, any point on the digging blade generates a cycloidal movement during the movement of this cultivator along the ground surface.

The digging blades may be either fixedly mounted in helicoidal positions on the digging blade wheel, or can be pivotally mounted on the wheel. A mechanism is provided in the hub of the digging blade wheel to pivot the digging blades through an angle of about 90 after each blade emerges from the ground bearing a lump of soil so that pivoting of the blade will deposit the lump of soil in either the same or in an adjacent furrow. Helicoidally mounted digging blades will deposit lumps of soil in the adjacent furrow.

Other objects and advantages of the present invention will be apparent upon reference to the acompanying description when taken in conjunction with the following drawings, wherein:

FIGURE 1 is a side elevational view of the rotary spading machine according to the present invention;

FIGURE 2 is a top plan view of the rotary spading machine illustrated in FIGURE 1;

FIGURES 3 through 5 are diagrams illustrating the cycloidal movement of the involute shaped digging blades, with FIGURE 3 representing a prior art cultivator;

FIGURES 6A and 6B are diagrams illustrating vectorially the relationships when the digging blade wheel rotates at different speeds with respect to the ground surface;

FIGURE 7 is an overall perspective view of a helicoidal digging blade wheel structure employed on the rotary spading machine of the present invention;

FIGURE 8 is a perspective view of a portion of a helicoidal digging blade mounted on the wheel structure of FIGURE 7;

' FIGURE 9 is a side elevational view of the concave or digging surface of a specially reinforced digging blade for the rotary spading machine of this invention;

FIGURE 10 is a front elevational view of a portion of a digging blade of FIGURE 9, with the reinforcing strip being shown in section;

FIGURE 11 is a perspective view of a digging blade Wheel of the present invention having pivotally mounted digging blades, with a portion of the wheel structure being cut away for purposes of clarity;

FIGURE 12 is a top plan view of another modification of a digging blade wheel provided with pivotally mounted digging blades;

FIGURE 13 is a side elevational view of the digging blade wheel shown in FIGURE 12;

FIGURE 14 is a partial sectional view taken along a plane perpendicular to the rotary axis of the digging blade wheel of FIGURES 12 and 13, and illustrating the mechanism for pivoting the digging blades;

FIGURE 15 is a partial sectional view taken along the rotary axis of a digging blade wheel of FIGURES 12 and 13, and further illustrating the pivoting mechanism shown in FIGURE 14;

FIGURE 16 is a view similar to that of FIGURE 14, and showing a modification of the mechanism for pivoting the digging blades;

FIGURE 17 is a side elevational view of a modification of the rotary spading machine of this invention;

FIGURE 18 is a top plan view of the modification shown in FIGURE 17;

FIGURE 19 is a side elevational view of the rotary spading machine of the present invention in another modification;

FIGURE 20 is a top plan view of the modification shown in FIGURE 19;

FIGURE 21 is a perspective view of a modified digging blade wheel according to the present invention, particularly adapted for use as a stone picker;

FIGURE 22 is a top plan view of a modified rotary spading machine provided with braking means;

FIGURE 23 is a side elevational view of a modified digging blade wheel provided with a deep cutting device;

FIGURE 24 is a top plan view of the modified digging blade wheel of FIGURE 23; and

FIGURE 25 is a top plan view of a modification of the present invention particularly adapted for digging a ditch.

With reference to the drawings wherein like reference numerals indicate the same parts throughout the various views, a specific embodiment and several modifications of the present invention will next be described in detail.

With particular reference to FIGURES 1 and 2, the rotary spading machine of the present invention comprises a frame 1 upon which a digging blade wheel structure 2 is mounted toward the rear thereof, while supporting wheels 3 and 4 are mounted on the frame toward the front thereof.

The construction of the digging blade wheel 2 is shown in greater detail in FIGURES 7 and 8 and comprises a tubular hub 5 which is rotatably mounted upon a shaft 6 which is stationary and mounted on the frame 1. The

hub 5 is provided at both ends with circular flanges 7 and 8.

A plurality of curved digging blades 9 (for example, three, four or six) are mounted helicoidally between the flanges 7 and 8 by means of projecting portions 9A and bolts 10, and each blade has an involute section when viewed axially of the blade wheel 2 with the involute being generated by a base circle coaxial with the wheel structure.

The involute cross section of the digging blades can be achieved during actual manufacture by fabricating the digging blades from portions having circular and straight cross sections.

The diameter of flange 7 is smaller than the diameter of flange 8 so that the dug-up lumps of earth may easily slide off helically shaped digging blades. The diameter of flange 8 is approximately equal to that of the contact circle which will presently be defined in detail.

In order to maintain the bottom of the furrow being formed in a straight line, parallel to the surface of the ground, the digging blade means should have such a length that it could be so spaced on the digging blade wheel that the tips of adjacent digging blades describe cycloidal curves which overlap each other inside the soil beneath the surface of the ground. Thereby a furrow is excavated whose bottom is of approximately uniform depth throughout the whole length thereof.

With

reference to'FIGURES

9 and 10, one edge of the digging blade 9 is reinforced near its tip in order to resist the'impact of heavy loads and to prevent distortion of the digging blades when penetrating into the soil.

This reinforcing structure comprises a crescent-shaped strip 27 which is fastened to the edge of the digging blade 9 by a number of bolts 27a whose heads are countersunk so that the tops of the heads will be flush with the digging blade surface. This reinforcing strip 27 is sharpened along its edge 2712 as illustrated in FIGURE 10, which is the cutting edge for the lateral side of the lump of earth to be dug up. The rear of the reinforcing strip 27 is shaped so as to decrease friction with the soil. The thick portion of the strip indicated at 270, is used for fastening the digging blades 9 to the flange 8 by the bolts 10, as described above.

If desired, the digging blades 9 may be further reinforced by employing special supports between the rear surface of the digging blade 9 and the flange 8.

Propulsion of the spading machine on the road with the digging blade wheel 2 in the raised position is obtained through the driving wheel 3 alone. The driving wheel 3 is rigidly mounted on a hollow shaft 11 which is rotatably mounted in the frame 1. A removable shaft 12 is rotatably supported within the hollow shaft 11 and the supporting wheel 4 is mounted on the shaft 12 with the result that the wheel 4 is freely rotatable.

A second frame structure 13 is pivotally attached to the hollow shaft 11 and carries a freely rotatable rear wheel 14, with a steering handle 15 being attached to this second frame 13. The shaft of the rear wheel 14 is positioned behind the shaft 6 of the wheel structure 2 when viewed in the direction of forward movement of the spading machine. The frame 13 also carries a pinion 16 to which is attached a hand wheel 17. The pinion 16 meshes with a rack 18 which is attached to the machine frame 1 near the shaft 6. The rear portion of the frame 1, together with the digging blade wheel 2, can be raised or lowered by rotating the pinion 16. A ratchet engageable with the pinion 16 may be employed to lock the frame 1 in a desired working position.

When the digging blade wheel 2 is raised, the spading machine can move freely since this digging blade wheel does not contact the ground surface. The freely rotatable supporting wheel 4 will be pulled somewhat laterally, as indicated by the dashed position as shown in FIGURE 2, because the digging blade wheel 2 is positioned laterally of the longitudinal center line of the spading machine. The balance of forces can also be obtained by using two adjustable supporting wheels. The spading machine can also be kept in equilibrium by the use of a counterweight 19, as shown in FIGURE 2.

The driving wheel 3 is driven by a motor 20 located at the front of the spading machine and mounted on the frame 1. The motor 20 powers the drive shaft 21 and power is transmitted to a shaft 24 through

gears

22 and 23. The shaft 24 transmits power to the hollow shaft 11 by a worm 25 meshing with suitable gearing on the hollow shaft 11. The driving of the wheel 3 in this manner will determine the forward speed of the spading machine.

The digging wheel 2 is driven by the gear 22 through a worm 26 which meshes with suitable gearing on the hub of the wheel 2.

In order to obtain the results of the present invention, the digging blade wheel must be driven at a particular speed relationship with respect to the speed with which the spading machine is propelled over the ground surface.

Contrary to the situation with the digging blade wheel 2 in its raised position, during which the wheel 3 propels the machine over the road surface, the actual propelling of the machine in its operative position (digging blade wheel lowered) is produced by the digging blade wheel, which crawls through the ground. The supporting wheel 3 once again determines the forward speed 6 of the spading machine, this time by exerting a braking force on the forward movement of the machine. This result is obtained with the aforementioned particular speed relationship. This speed relationship can be clearly described geometrically by reference to the following terms:

Contact circle.A cross section of the cylindrical surface defined by the points on the digging blades which merely contact the surface of the earth without penetrating into the same.

lnvolute circle.A base circle for generating the in volute profile of the digging blades on the digging blade wheel structure.

Generating circle-Since the cycloid is generated by a point upon the circle which rolls along a straight line, it is this circle which isreferred to when describing the cycloidal movement of the digging blade Wheel.

This generating circle is a circle which makes a rolling movement over a surface without slipping. Normally when a wheel rolls over a surface, the generating circle corresponds with the outer circumference of the wheel which is in contact with the surface. If, however, the rotation of the wheel is somewhat greater than would correspond with the correct rolling (without slipping) over the surface, the radius of the generating circle is somewhat reduced so that the wheel in question may be considered to roll over a hypothetical surface which is positioned closer to the rotational axis of the wheel than the surface in contact with the outer circumference of the wheel.

This relationship may be further clarified by reference toFIGURES 6A and 613 where FIGURE 6A illustrates the situation wherein the wheel rolls without slipping over a surface. V represents the forward velocity of the vehicle, V represents the velocity of the circumference of the Wheel relative to the surface, and w repre sents the angular velocity of the wheel.

It is pointed out that the'velocity of the circumference of the wheel at the lowest point of the wheel is zero which means that there is rolling without slipping. Thus the linear speed at this lowest point of the wheel with respect to the surface is zero.

In FIGURE 6B, a situation isshown wherein the angular velocity of the wheel is somewhat greater than would correspond with the correct rolling (with-out slipping) over the surface. It is noted that the velocity of the outer circumference of the wheel with respect to the surface at the lowest point of the wheel is no longer zero but has a small negative value.

It can be further appreciated that under these circumstances the correct rolling occurs on a hypothetical surface which is at a shorter distance from the rotational axis of the wheel dependent upon the increase in angular velocity of the wheel with respect to the situation illustrated in FIGURE 6A.

Therefore, FIGURE 68 illustrates the situation which actually exists in the rotary spading machine according to the present invention.

In view of this speed relationship, geometrically speaking, the radius of the generating circle of the cycloid is somewhat smaller than the radius of the contact circle.

With reference to the diagrams of FIGURES 3 through 5, the principles of the present invention will be further described in these schematic presentations of the speed relationship between the digging blade wheel and the forward speed of the spading machine when viewing the digging blade wheel in a plane perpendicular to its rotary axis.

FIGURE 3 represents the speed relationship resulting when a drum-like cultivator is dragged over the ground according to the prior art. In this figure, the generating circle b of the cycloidal movement has the same radius as the involute circle 0 from which the involute cross section of the digging blades is generated. Also in this figure, the generating circle b has the same radius as the contact circle a-it being noted that the radius of this contact circle represents the shortest distance from the rotary axis of the digging blade wheel to the ground surface. It is thus seen that in FIGURE 3, the radii of the contact circle a, the generating circle b, and the involute circle are identical. The generating circle b is illustrated in eight different positions, together with the corresponding positions, adopted by a single digging blade. Each point on a digging blade follows a cycloidal curve.

In position I, a typical digging blade just contacts the ground surface. In position VIII, the digging blade has obtained its maximum length of penetration into the ground, i.e. since b equals c the digging blade is deeply buried. The point of the digging blade which is located at the surface of the soil in each position operates as the pivoting point of the shovel during its movement below the surface of the ground. The actual digging up action of the digging blade occurs only after the digging blade has reached its greatest depth of penetration into the soil which corresponds to position V but is not identical with the greatest length of penetration of the digging blade.

In FIGURE 4 is illustrated the various positions I-VIII of a digging blade carrying out a cycloidal movement wherein generating circle b has a smaller radius than the contact circle a. The involute circle 0 of the involute has the same radius as the generating circle b.

In FIGURE 5, the generating circle b also has a radius smaller than the contact circle a. The base circle 0 of the involute, however, has the same radius as the contact circle a.

In both FIGURES 4 and 5, there occurs a retracting movement of the digging blade in the soil. This movement provides for thinner slices of soil being dug up so that the portions of soil cannot stick between adjacent digging blades. This retracting movement also withdraws the contact surface of the digging blade from the undug soil in front of the digging blade, thus reducing the friction between the digging blade and the undug soil.

It has been determined that the speed relation illustrated in FIGURE 5 provides the best results with the present spading machine. In this relationship the radius of the involute circle c is greater than the radius of the generating circle b and identical with contact circle a. Specifically, these results are attained when the radius of the generating circle b is from 100% to 30% of the radius of the contact circle a. Preferably and for optimum results, the radius of the generating circle should be from 80% to 60% of the radius of the contact circle. It has also been discovered that the radius of the involute circle should be less than the radius of the contact circle.

' The speed ratios of the various components of the power trains in the spading machine of the present invention are such that when the driving wheel 3 is rolling on the ground surface, the speed at the bottom of the contact circle a of the digging blade wheel 2 is small, but in an opposite direction with respect to the forward -movement of the machine over the ground. 7

The following is a specific example through which the aforementioned speed relationship is obtained.

Speed of motor 20 3000 rev/min. Gear ratio 22 1:5. Gear ratio 23 4:5. Worm ratio 25 1:20. Worm ratio 26 1:20. Diameter of contact circle of the shovel-bearing wheel 2 24". Diameter of driving wheel 3 24". Speed of the machine 3 ft./sec.=2 m./h.

To further illustrate the principles of the present invention, the following are the dimensions of a digging blade wheel and circles as described above, similar to 8 the 6-bladed spading machine illustrated in FIGURE 1 of the drawings:

Cm. Outer diameter of digging wheel 105 Diameter of contact circle a 51 Diameter of generating circle b 45 Diameter of involute circle c 48 Spading depth 27 The above dimensions will give the proper relationship for achieving the results of the present invention as described above. The lower limit of the diameter of the generating circle is 17 cm. which is about 30% of the diameter of the contact circle.

If the diameter of the generating circle falls below the lower limit of 30%, then the lumps of earth dug up by the digging blades will be thrown out too far because of the centrifugal force of the rapidly rotating shovel wheel. This will not produce the result of the present in vention, namely to dig up lumps of earth and deposit them in place on the surface of the ground.

The spading machine of the present invention is operated in the following manner:

During the transfer of the spading machine to the land to be cultivated, the gear 22 is disconnected from worm 26. The frame 1 is raised so that the digging blade wheel 2 does not touch the ground. Engine 20 will propel the driving wheel 3. Whenit is desired to commence the plowing, gear 23 is disconnected from worm 25 and the driving wheels (one or both) are locked, then gear 22 is shifted into engagement with worm 26 and the ratchet of gear 16 is disengaged. Motor 20 now drives only the digging blade wheel 2. The digging blade wheel 2 will dig into the ground until its deepest point of penetration has been reached. This depth of digging is controlled either by bearing flange 8 on one side of the wheel, by laterally projecting elements (not shown) attached to the digging blades, or through a limiting connection between the frame 1 and the secondary frame 13 After the digging blade wheel has penetrated into the ground, the driving wheels are released and gear 23 is again engaged with worm 25. At this point the actual plowing begins. The spading machine is steered 'by a handle 15. During the movement of the machine the dug-up earth is sliding downwardly and laterally off the helicoidally mounted blades 9 and will to some extent be deposited rearwardly of the machine as the result of centrifugal force. The dug-up lumps of earth are rotated through an angle of about prior to being deposited back on the surface of the ground.

The above described embodiment employs digging blade wheels having digging blades helicoidally mounted on the wheel structure. The rotary spading machine of the present invention, however, also employs digging blades which are not helicoidal in shape, but whose bases are parallel with the rotary axis of the digging blade wheel. If it is desired to deposit the dug-up lumps of soil laterally into an adjacent furrow or directly into the same freshly plowed furrow, the digging blades can be operated through a mechanism which pivots the blades.

In FIGURE 11 there is illustrated a modified digging blade wheel employing pivotally mounted digging blades. This digging blade wheel comprises

coaxial cylinders

60 and 61. -Digging blades 63 are mounted onblade shafts 62a which are inserted into the tubular member 62. The pivoting or tilting mechanism is mounted within the cylinder 60 which engages the lower end of the digging blade shaft 62a to pivot the digging blades in a predetermined manner.

Under certain circumstances, it is desirable to position the tubular members 62 so that they cross over the main shaft 5 of the digging blade wheel and are not positioned radially to this shaft. As a result, the digging blade shafts remain in one or more planes perpendicular to the main shaft 5 but the axes of the blade shafts do not intersect the central axis of the main shaft 5.

The digging blade shafts can be fastened either to the center or to either side of the digging blades. Both arrangements will facilitate the depositing of lumps of soil directly into the freshly plowed furrow. Pivoting mechanism operates to pivot the digging blades at the right moment to accomplish this deposition of the lumps of soil. In the digging position, the blade has its surface substantially parallel to the central axis of the wheel structure and the blade is pivoted about 90 after lifting a lump of soil to deposit this lump on its side.

A further modification having pivotable digging blades is illustrated in FIGURES 12 through 16. This modification of the digging blade wheel is particularly adapted for use on a rotary spading machine attached to a tractor and driven by the tractor power take-off shaft. The wheel has a plurality of adjacent digging blade wheels with each wheel comprising four pivotally mounted digging blades.

This spading machine is mounted on the conventional 3-point hitch found on agricultural tractors. Changing of the gear ratio of the tractor will change the speed of the digging blade wheel and hence vary the generating circle. Generally, the contact circle will remain constant.

The digging blades are pivotally mounted on the rotary spading machine with a cam mechanism being provided to pivot the digging blades in a predetermined manner. The digging blades similarly have involute cross-sections and are mounted on the end of curved supporting arms which in turn are pivotally mounted on the hub of the spading machine. During the actual penetration of the digging blades into the soil, the surface of the digging blade is parallel to the rotary axis of the digging blade wheel. After the digging blade emerges from the soil bearing a lump of earth, the blade is then tilted to an angle of about 90 to dump the lump of soil in the same or in an adjacent furrow.

Each digging blade 9 is fixed upon a curved supporting arm 90 with said arms being rotatably mounted on a casing 91. The casing 91 is mounted around a cylindrical hub 92 which is coaxial with the main shaft 5. A mechanism for pivoting the blades 9 according to a predetermined manner is enclosed in the casing 91. As can be seen from FIGURE 12, the digging blade may be mounted at its center line to the supporting arm 90 (full lines), or at one side of the center line.

The adjacent casings 91 are angularly displaced with respect to each other. This produces a more uniform load on the engine as the digging blades penetrate into the soil at different times. Further, it facilitates the pivoting movement of the blades as the displacement of one blade is not hindered by a blade in an adjacent set of blades.

A mechanism for pivoting the digging blades of FIG- URES l2 and 13 is illustrated in FIGURES l4 and 15 and will be described in detail. Each curved support arm 90 is fixed to a shaft or stub axle 93 mounted inbores 94 and 95 of the casing 91 in such a manner that the various shafts 93 extend in a plane substantially perpendicular to the main shaft of the digging bladewheel. A portion of each of the shafts 93 between the

bearings

94 and 95 has been flattened on opposite sides. Through a hole in this flattened portion a bolt 96 supports a follower arm 97 in a position perpendicular to the shaft 93 in a direction toward the axis of the main shaft 5. A roller 98 which is essentially a cam follower, is rotatably mounted on the end of the arm 97. A- cylindrical cam block 99 is fixedly mounted coaxially on the shaft 5. The cam block is provided with a curved cam groove 100 around its circumference. A major portion of the groove is such that the rollers 98 are kept in a position as indicated in the upper portion of FIGURE 15. The digging blades 9 are then in the digging position.

In a further portion of the cam groove the curvature changes so that after about a 45 rotation of the digging blade wheel, the shaft 93 is rotated through an angle of at least 90. The digging blades 9 are then in what might be called the delivery or deposit position for dumping the lumps of soil. In the lower portion of FIGURE 15, the shaft 93 is illustrated as being midway between these two above-mentioned positions. The pivotingmov'ement of the digging blade begins when the' digging'blade is in the position indicated at VIII in FIGURES. However, this moment can be delayed if required. In the last portion of the cam groove 100 the roller 98 is returned to its position as indicated in the upper portion of FIGURE 15. The digging blade willthen again'be brought in its digging position.

In this modification as illustrated in FIGURES 12-15, each set of digging blades has its own cam block for guiding the pivoting movement of the digging blades.

Proceeding next to FIGURE 16, there is'show'n'a-modified pivoting mechanism utilizing a longer moment arm between the stub axle of the digging blade and'the cam follower. This reduces the forces exerted on the mechanism without the necessity for enlarging the outer dimensions of the hub of the digging blade wheel. In this modification the cam follower engages the cam profile over an arc distance of at least 45 and'prefe'rably from that area of the 'cam groove which is nearest to the stub axle upon which that particular follower arm is mounted.

A portion of one digging blade wheel is shown in FIGURE 16 and is illustrated at200'. This'unit comprises a central stationary shaft 201' having a cam block 202 fixedly mounted thereon, with'a cam groove 203 being provided in the circumference 'of the 'cam block. The cam block is enclosed by a'rotatable tubular hub 204, the rotary axis of which coincides with the central axis of the shaft 201. Tangentially supported in bearings 205 and-206 along the outer circumfer'ence of the hub 204, are three stub axles 207. Secure'd'to the end 208 of the stub axle is a diggingblade (not shown) which has an involute cross section as described previously.

Mounted on each stub axle 207 is a curved follower arm 209 extending in the annular space between the outer circumference of the cam block 202 and the inner circumference of the hub 204. On'the inner end of the follower arm 209' is mounted a shaft 210 upon which is rotatably mounted a roller 211 which functions as a cam follower and is engageable with the' cam groove 203.'

As-is clearly apparent from FIGURE 16, the cam follower 211 engages the cam groove 203 over are distance of about 90 from that area ofthe cam'groove which is nearest to the stub'axle 207; Accordingly, a sufficiently long lever arm is obtained, as indicated at A, for pivoting the stub axle 207 and the digging blade mounted thereon. Accordingly, the forces ex'ertec l between the cam follower 211 and the cam'block 202*are considerably reduced and remain well underthe maximum limits whereby the operatinglife of thepivoting mechanism is considerably lengthened? Because of'the position of the cam' follower'211 With respect to the stub axle 207, a rather large movement willhave to be imparted to this cam' follower by the cam profile 203 in order to achieve a pivotin'g of the digging blade through an angle of at lea'st'90.

Where the rotary spading machine comprises a plurality of such spading units, positioned adjacent each other, no difiiculties are experienced as in an axial direction with respect to the central shaft 201 sufiicient space is provided for each spading unit.

FIGURES 17 and 18 show a rotary spading machine frame 1 and a digging blade wheel 2 with a front supporting wheel 30 and an upwardly and downwardly displaceable rear supporting wheel 31. The'digging blade wheel 2 can be raised or lowered into the soil with the aid of the wheel 31. The wheel '30' and the digging blade wheel 2 are driven in the same manner as in the embodiment illustrated in FIGURES 1 and 2.

A multi-unit spading machine is shown in FIGURES blades are mirror images of each other.

19 and 20. The frame 1 carries three

digging blade wheels

50, 51 and 52 mounted in corresponding bearings and driven by

chains

50a, 51a and 52a. Through the staggered position of the digging blade wheels a compact and space saving construction is obtained which enables a wider tract of ground to be spaded. Digging blade wheel 52 in the rearward portion deposits dug up soil in the furrow of wheel 51 and this in turn deposits its dug up soil in the furrow of wheel 50. The frame 1 is provided at both ends with supporting wheels 53 which may raise or lower the body so as to vary the height of the digging blade wheels above the ground similar to the modification illustrated in FIGURES 17 and 18. The seat for the operator of the machine may be provided on top of the plow.

Proceeding next to FIGURE 21 there is shown a further modification of the present invention which is particularly adapted for picking up the stones from a field or digging up potatoes or other tuberous plants. In this modification the digging blades are so positioned on the wheel that the surfaces are parallel to the rotary axis of the digging blade wheel. As a result dirt dug up by these blades is transported into the interior of the wheel. From the interior of the wheel the soil can be ejected laterally of the wheel or handled in any other desired .way. Accordingly, the soil may be sieved inside the wheel whereupon the soil is returned to the ground after having passed through the sieve. Stones, however, will be laterally discharged therefrom.

In this modification a digging blade wheel comprises a flange 71 attached to a hub 70, with the flange 71 .carrying a plurality of digging blades 72, with each blade having a plurality of tines thereon. These fork-like digging blades are attached to a ring 73. A basket-shaped sieve 75 is suspended from the hub 70 and remains in the correct position by gravity. The dug-up soil descends into the sieve. Because of the tilted position of the sieve, the stones or the like will roll laterally out of the wheel through opening 74 and may be easily gathered. The speed of rotation of this wheel should be so low as to prevent discharge of the dug-up soil by centrifugal force. The width of this wheel can be substantially greater than the width of a shovel bearing wheel having helicoidally shaped blades.

In FIGURE 22 there is illustrated a rotary spading machine having a single digging blade wheel 2 driven by the motor 20. In order to slow down the forward movement of the machine resulting from the rotation of the shovel bearing wheel, the spading machine drags a harrow 28 or imilar agricultural implement which has a braking effect. At the same time, the surface of the soil is graded or leveled.

FIGURES 23 and 24 illustrate a digging blade wheel .81 to which is added a star-shaped wheel of sheet metal 80 attached coaxial on the side of the digging blade wheel. This star wheel functions as a deep cutter for cutting up any impermeable layer of the sub-soil. In FIGURE 23 a top soil is indicated at 82, and the impermeable layer of the sub-soil which is penetrated by the star wheel is indicated at 83.

Proceeding next to FIGURE 25, there is shown a modification of the rotary spading machine of the present invention which is particularly adapted for digging a ditch.

.This modification essentially comprises an arrangement of a pair 'of similar digging wheels 2 positioned adjacent each other and coaxially, but with the digging blades being inverted symmetrically with respect to the vertical central plane of the spading machine. As'a result, the digging The arrangement of digging wheels is pulled by a tractor 29. The wheels are driven through a transmission enclosed in the housing 2a and powered through a conventional power take-off shaft of the tractor. The digging blades 9 may be of the helicoidal type or of the pivoting type. Thus the digging action of these two digging blade Wheels will dig up lumps of dirt and throw the lumps of the dirt to the side of the furrow which is dug. The result Will be a clean ditch having a width substantially equal to the combined width of the two digging blade wheels.

If the digging blade wheels are provided with helicoidally mounted digging blades, it is necessary to have the tip of the blade which penetrates the soil positioned at that side of the digging blade Wheel Which faces rearwardly with respect to the direction of movement of the rotary spading machine. As a result, a furrow of maximum width is dug by overlapping the work of two adjacent digging blade wheels.

Thus, it can be seen that the present invention discloses a rotary spading machine which closely simulates a manual grading of the soil. The spading machine may be provided with fixedly mounted helicoidally shaped digging blades or with pivotally mounted digging blades which can be pivoted in a predetermined manner by mechanisms supported in the hub of the digging blade wheel. The rotary spading machine may be further modified as described above, to accomplish several important agricultural tasks.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

What is claimed is:

1. A rotary spading machine comprising a frame supported for movement over the ground surface, a wheel structure mounted for rotation on said frame, a plurality of digging blades mounted on said Wheel structure for rotation therewith and curving outwardly therefrom in the direction of rotation thereof, a portion of each blade when viewed axially of the wheel structure defining an involute generated by a base circle coaxial with the axis of rotation of said wheel structure, driving means for rotating said wheel structure in the direction corresponding to the direction of movement of the machine over the ground surface at such a speed that the generating circle of the cycloidal movement of said digging blades has a radius of 90% to 30% of the radius of the contact circle formed by the cross section of a cylindrical surface contacting those points on said blades which contact the ground surface without penetrating the same, the base circle of said involute having a diameter greater than the diameter of said generating circle and smaller than the diameter of said contact circle.

2. A rotary spading machine as claimed in claim 1, wherein said digging blades are mounted helicoidally on said wheel structure, the leading edge of one blade coinciding with the trailing edge of the next adjacent blade when viewed in an axial direction.

3. A rotary spading machine as claimed in claim 1, wherein said digging blades are so spaced around said wheel structure that each blade will start penetrating into the soil when the preceding blade has completely entered into the soil.

4. A rotary spading machine as claimed in claim 1, wherein the generating circle of the cycloidal movement of said digging blades has a radius of from to 60% of the radius of the contact circle formed by the cross section of a cylindrical surface contacting those points on said blades which contact the ground surface without penetrating the same.

5. A rotary spading machine comprising a frame supported for movement over the ground surface, means for propelling said frame over said ground surface, a wheel structure mounted for rotation on said frame, a plurality of digging blades mounted on said wheel structure for rotation therewith and curving outwardly therefrom in the direction of rotation thereof, a portion of each blade when viewed axially of the wheel structure defining an involute generated by a base circle coaxial with the axis of rotation of said wheel structure, driving means for rotating said wheel structure in the direction corresponding to the direction of movement of the machine over the ground surface at such a speed that the generating circle of the cycloidal movement of said digging blades has a radius of 90% to 30% of the radius of the contact circle formed by the cross section of a cylindrical surface contacting those points on said blades which contact the ground surface without penetrating the same, the base circle of said involute having a diameter greater than the diameter of said generating circle and smaller than the diameter of said contact circle.

6. A rotary spading machine comprising a frame supported for movement over the ground surface, a wheel structure mounted for rotation on said frame, a plurality of digging blades mounted on said wheel structure for rotation therewith and curving outwardly therefrom in the direction of rotation thereof, a portion of each blade when viewed axially of the wheel structure defining an involute generated by a base circle coaxial with the axis of rotation of said wheel structure, digging blades being so spaced on said wheel structure that the tips of two adjacent digging blades describe cycloidal curves overlapping each other below the surface of the soil, driving means for rotating said wheel structure in the direction corresponding to the direction of movement of the machine over the ground surface at such a speed that the generating circle of the cycloidal movement of said digging blades has a radius of 90% to 30% of the radius of the contact circle formed by the cross section of a cylindrical surface contacting those points on said blades which contact the ground surface without penetrating the same, the base circle of said involute having a diameter greater than the diameter of said generating circle and smaller than the diameter of said contact circle.

7. A rotary spading machine comprising a frame supported for movement over the ground surface, a wheel structure mounted for rotation on said frame, a plurality of digging blades pivotally mounted on said wheel structure for rotation therewith and curving outwardly therefrom in the direction of rotation thereof, said digging blades being pivotable over an angle of at least 90, a portion of each blade when viewed axially of the wheel structure defining an involute generated by a base circle coaxial with the axis of rotation of said wheel structure, driving means for rotating said wheel structure in the direction corresponding to the direction of movement of the machine over the ground surface at such a speed that the generating circle of the cycloidal movement of said digging blades has a radius of 90% to 30% of the radius of the contact circle formed by the cross section of a cylindrical surface contacting those points on said blades which contact the ground surface without penetrating the same, the base circle of said involute having a diameter greater than the diameter of said generating circle and smaller than the diameter of said contact circle.

8. A rotary spading machine comprising a frame supported for movement over the ground surface and having a stationary shaft thereon, a wheel structure having a tubular hub mounted for rotation on said stationary shaft, a plurality of digging blades mounted on said wheel structure for rotation therewith and curving outwardly therefrom in the direction of rotation thereof, a portion of each blade when viewed axially of the wheel structure defining an involute generated by a base circle coaxial with the axis of rotation of said wheel structure, said digging blades each having a stub axle with said stub axles being pivotally mounted on said hub tangentially with respect thereto, a cam follower mounted on each of said stub axles and extending into said hub, a cam fixedly mounted on said stationary shaft, said cam having a groove with side surfaces, said cam side surfaces being engageable by said cam follower to swing said cam follower through a 90 arc, said are being in a plane transverse to and symmetrical to a plane including the axis of the respective stub axle and perpendicular to the axis of the shaft, said cam follower pivoting said digging blades through an angle of about in ,a predetermined manner as said wheel structure rotates on said shaft, driving means for rotating said wheel structure in the direction corresponding to the direction of movement of the machine over the ground surface at such a speed that the generating circle of the cycloidal movement of said digging blades has a radius of 90% to 30% of the radius of the contact circle formed by the cross section of a cylindrical surface contacting those points on said blades which contact the ground surface without penetrating the same, a base circle of said involute having a diameter greater than the diameter of said generating circle.

9. A rotary spading machine comprising a movable frame having a stationary shaft thereon, a Wheel structure having a tubular hub rotatably supported on said stationary shaft, said wheel structure including a plurality of digging blades each having a stub axle with said st-ub axles being pivotally mounted on said hub tangentially with respect thereto, a cam follower mounted on each of said stub axles and extending into said hub, and a cam fixedly mounted on said stationary shaft, said cam having a groove with side surfaces, said cam side surfaces being engageable by said cam followers to swing said cam follower through a 90 are, said are being in a plane transverse to and symmetrical to a plane including the axis of the respective stub axle and perpendicular to the axis of the shaft, said cam follower pivoting said digging blades in a predetermined manner as said wheel structure rotates on said shaft.

10. A rotary spading machine comprising a movable frame having a stationary shaft thereon, a wheel structure having a tubular hub rotatably supported on said stationary shaft, said wheel structure including a plurality of digging blades each having a stub axle with said stub axles being pivotably mounted on said hub tangentially with respect thereto, a cam follower arm mounted on each of said stub axles and extending radially into said hub and having a cam follower mounted on the inner end thereof, and a cam fixedly mounted on said stationary shaft and having a channel-shaped cam surface engageable by said cam follower to swing said cam follower through a 90 arc, said are being in a plane transverse to and symmetrical to a plane including the axis of the respective stub axle and perpendicular to the axis of the shaft, said cam follower pivoting said digging blades in a predetermined manner as said wheel structure rotates on said shaft.

11. A rotary spading machine comprising a movable frame having a stationary shaft thereon, a wheel structure having a tubular hub rotatably supported on said stationary shaft, said wheel structure including a plurality of digging blades each having a stub axle with said stub axles being pivotably mounted on said hub tangentially with respect thereof, a cam fixedly mounted on said stationary shaft and having a cam surface thereon, the tangential positions of said stub-axles being adjacent the periphery of the cam, and a cam follower mounted on each stub axle and engageable with said cam surface at an arc distance extending circumferentially about 45 90 from that area of the cam surface which is closest to that stub axle to which the respective follower is mounted whereby said digging blades are pivoted in a predetermined manner during the rotation of said wheel structure on said shaft.

12. A rotary spading machine comprising a movable frame having a stationary shaft thereon, a wheel structure having a tubular hub rotatably supported on said stationary shaft, said wheel structure including a plurality of digging blades each having a stub axle with said stub axles being pivotally mounted on said hub tangentially with respect thereof, a cam fixedly mounted on said stationary shaft and having a cam surface thereon, the tangential positions of said stub axles being adjacent the periphery of the cam, a cam follower arm mounted on each stub axle and extending into theannular space between said hub and said cam, the inner ends of said cam follower arms being positioned between the stationary shaft and the next adjacent stub axle, and a cam follower on the inner end of each follower arm and engageable with said cam surface at an arc distance extending circumferentially about 90 from that area from said cam surface which is closest to the stub axle on which the respective follower arm is mounted whereby said digging blades are pivoted in a predetermined manner during the rotation of said wheel structure on said shaft.

13. A rotary spading machine particularly adapted for digging ditches, and comprising a frame supported for movement over the ground surface, a pair of coaxial wheel structures mounted on said frame for rotation in the same direction, a plurality of digging blades helicoidally mounted on both of said wheel structures for rotation therewith and curving upwardly therefrom in the direction of rotation thereof, a portion of each blade when viewed axially of its respective wheel structure defining an involute generated by a base circle coaxial with the axis of rotation of said wheel structure, said digging blades on one wheel structure being positioned invertedly symmetrical to the digging blades on the other wheel structure so that said digging blades are mirror images relative to a plane between said wheel structures in the direction of movement of the machine, driving means for rotating both of said wheel structures in the direction corresponding to the direction of movement of the machine over the ground surface at such a speed that the generating circle of the cycloidal movement of said digging blades hasa radius of 90% to 30% of the radius of the contact circle formed by the cross section of the cylindrical surface contacting those points on said blades which contact the ground surface without penetrating the same, the base circle of said involute having a diameter greater than the diameter of said generating circle, the reverse positions of the digging blades on one wheel structure with respect to the digging blades of the other wheel structure discharging lumps of soil laterally outwardly from said pair of wheel structures.

14. A rotary spading machine particularlyadapted for digging ditches, and comprising a frame supported for movement over the ground surface, a pair of coaxial wheel structures mounted on said frame for rotation in the same direction, a plurality of digging blades pivotally mounted on both of said wheel structures for rotation therewith and curving upwardly therefrom in the direction of rotation thereof, a portion of each blade when viewed axially of its respective wheel structure defining an involute generated by a base circle coaxial with the axis of rotation of said wheel structure, said digging blades on one wheel structure being positioned invertedly symmetrical to the digging blades on the other wheel structure so that said digging blades are mirror images relative to a plane between said wheel structures in the direction of movement of the machine, driving means for rotating both of said wheel structures in the direction corresponding to the direction of movement of the machine over the ground surface at such a speed that the generating circle of the cycloidal movement of said digging blades has a radius of to 30% of the radius of the contact circle formed by the cross section of the cylindrical surface contacting those points on said blades which contact the ground surface without penetrating the same, the base circle of said involute having a diameter greater than the diameter of said generating circle, the reverse positions of the digging blades on one Wheel structure with respect to the digging blades of the other wheel structure discharging lumps of soil laterally outwardly from said pair of wheel structures.

References Cited by the Examiner UNITED STATES PATENTS 93,494 8/69 Stevens 17271 101,710 4/70 Chenoweth l72546 704,857 7/02 Castelin l72556 1,878,442 9/ 32 Hamshaw 172-43 2,342,032 2/44 Bagan l72532 3,012,616 12/6 1 Horowitz l7294 3,120,279 2/ 64 Horowitz l72546 X FOREIGN PATENTS 71,108 2/ 16 Austria.

965,868 2/50 France.

717, 174 2/ 42 Germany.

927,820 6/63 Great Britain.

ABRAHAM G. STONE, Primary Examiner.