US2757463A - Excavating apparatus and method - Google Patents

Description

1mg 7, 1956 F. F KQLBE 2,757,463

EXCAVATING APPARATUS AND METHOD Filed April 12, 1952 470 2 E 5 36} S E r J Z6 M :w

T1 n l I laziufi tias fi 1 92525 f 3 ;/2 Agai ullllll 38 INVENTOR.

BY 5W4. 6m @M 2,757,463 nxoava'rnso arranaros AND METHOD Frank E. Kellie, Chicago, Iii assignor to The United Electric Coal Companies, Chicago, Iii, a corporation of Delaware Application April 12, @522, Serial No. 281,950 ill Ciaims. (til. 37--l19ll) The present invention relates to excavating apparatus, and particularly to apparatus of the type adapted for removal of earth materials in mining operations or the like.

The invention is particularly adapted for the removal of soil covering mineral deposits to be mined by openpit methods, but is also capable of use in removing soil and mineral deposits in underground mines.

Heretofore, excavating apparatus adapted for removal of overburden in open-pit mining has included a large rotatable wheel carrying a plurality of digging buckets at its periphery adapted to cut into and scoop up a quantity of soil and to discharge the same radially inwardly of the wheel when the buckets reach their uppermost position of travel. The bucket wheel is normally mounted for rotation at the end of a supporting ladder, and a belt conveyor is provided on the ladder and extends alongside and generally parallel to the plane of the wheel to carry soil excavated by the wheel to a point of disposal. To transfer the soil from the wheel to the conveyor, it is necessary to provide a slope sheet extending into the wheel beneath the uppermost positions of the buckets to transfer the soil sideways to the conveyor.

Bucket wheel excavators have the disadvantage that the soil contained in the buckets must travel to approximately top center of the wheel before the soil gravitates to the slope sheet. Accordingly, the soil has a substantial vertical drop, equal approximately to the radius of the wheel, with the result that the slope sheet and the conveyor belt are subjected to considerable impact causing rapid wear, deterioration and damage to the enumerated members and other members of the structure. Because of the time involved in the vertical drop of the soil and due to the fact that the soil must be moved transversely of the wheel, bucket wheels must be run quite slowly, such, for example, as three or four revolutions per minute. The soil removal capacity of bucket wheel excavators is limited, since increased capacity of the individual bucketspor the provision of an increased number of buckets, is gained only by increasing the size of the wheel, which leads to a necessity for decreased speed of operation. In addition to the foregoing, the Wheels must be operated at slow speed since centrifugal force tends to hold the soil in the buckets if the wheel is operated fast.

A further disadvantage of bucket wheel excavators is that dirt or soil accumulates on the inside of the buckets. if only of an inch builds up each revolution, in a half hour approximately an inch of material has built up, and sometimes the build-up is more rapid than the example given. This materially reduces the capacity of the buckets and also causes the remaining material to fall more slowly from the buckets so that the wheel must be operated at reduced speed. In order to keep the buckets relatively clean, electric heaters and complicated mechanical systems of cleaning have been utilized. in general, however, the wheels have been cleaned by hand, which involves a considerable loss of time.

Since the conveyor belt in bucket wheel excavators extends parallel to the wheel and the material is fed to atent the belt transversely of the wheel and bolt, the belt is subjected to transverse strain and is also required to accelerate the material transferred thereto, which results in decreased serviceability of the belt.

Another disadvantage is that large rocks and frost lumps are carried by the teeth of the buckets to top center of the wheel and then dropped, with substantial impact, to the belt. The impact further accelerates deterioration of the belt and, in addition, the belt is not adapted to carry such large rocks or lumps of material.

An object of the present invention is to provide excavating apparatus overcoming the disadvantages of the bucket wheel excavators and wherein the buckets are eliminated.

Other objects of the invention are to provide excavating apparatus that is self-cleaning, has a greater capacity for a given size, has unlimited speed of operation, is of simplified construction, requires less repair, breaks up all material fed to the conveyor to proper size for handling by the conveyor and feeds the material to the conveyor in the direction of travel of the conveyor.

In accomplishing the objects of the invention, I provide an excavating apparatus having a cutting wheel com prising two spaced rows of cutters or cutting blades rotated at the same speed and in the same direction. The cutters of each row are inclined from the outside toward the inside of the wheel in the direction of rotation of the cutters. The space between the rows of cutters defines the soil accumulating and moving space of the excavator and determines in part the capacity of the excavator.

The cutters or cutting blades are adapted to be moved, while rotating, sideways against a bank of soil. The inclined blades of the row which is moved against the soil cut the soil and move it into the space between the rows of cutters. The cutters of the other row are inclined in the opposite direction. Thereby the pairs of spaced cutters of the two rows of cutters carry the soil between them. The bank against which the excavator is operating forms an end wall for the spaces between the pairs of spaced cutters of the two rows of cutters. The cut! material is urged away from the bank of soil by the blades due to the inclination and rotation of the blades. A guide plate extends into the space between the rows of cutters and the material cut by the blades is moved onto the plate which guides the material onto a conveyor belt extending toward the rows of cutters. The conveyor belt is operated at substantially the same speed as the feed of material thereto so that the belt need not accelerate the material.

The excavating apparatus of the present invention has the advantages that: the soil need travel only the length of the cutting blades to bedischarged; centrifugal force and peripheral speed cooperate to discharge the material cut; the wheel may be operated at any desired speed; the soil being cut effects an automatic cleaning of the cutting blades; the soil is moved onto the belt in the direction of travel thereof; the wheel may be moved sideways at such rate that the soil is broken up for ready transporta tion by the conveyor belt; lumps or rocks of a large size are automatically kept out of the space between the cutting rows; and for a predetermined digging capacity the structure of the present invention is much lighter and smaller than the bucket type wheel.

One further disadvantage of bucket wheel excavators is that the cutting action was necessarily made in an upward direction. Accordingly, the supporting ladder had to support the entire weight of the wheel, the material therein, the conveyor and the material thereon. While the apparatus of the present invention may be operated to have an upward cutting action, the weight of the digging structure itself is smaller than in the case of a bucket type wheel of comparable capacity. Furthermore, one

decided advantage of the present apparatus is that it is particularly adapted for cutting in a downward direction, whereby a part of the weight of the cutting wheel, the conveyor and the material may be supported on the ground so that the supporting structure may be made of lighter section and more economical construction than was heretofore possible.

While reference has been made hereinbefore to a cutting wheel having spaced rows of cutting blades thereon, the preferred embodiment of the present invention includes a pair of relatively narrow wheels, each having a singlerow of blades thereon, the wheels being spaced from one another for the reception therebetween of mechanism for driving the wheels, and of the guide plate and the conveyor. This construction has the advantages that the structure is lighter and more compact and the capacity of the space between the rows of cutters is in creased.

Other objects and advantages of the invention will become apparent from the following detailed description of preferred embodiments of the invention, wherein ref erence is made to the accompanying drawings, in which:

Figure l is a side elevation of excavating apparatus of the present invention adapted to cut downwardly and shown engaging a bank of soil to be removed;

Figure 2 is a plan view of the apparatus shown in Figure 1; and

Figure 3 is a side elevation, similar to Figure l, of apparatus adapted to cut upwardly.

Referring to the drawings, and particularly to Figures 1 and 2, the apparatus of the present invention includes a frame or digging ladder, indicated generally at 10, which is adapted to be pivotally supported for horizontal and vertical swinging movement. The manner of supporting the frame or ladder is well known and is not shown herein. The frame or ladder 10 is further particularly adapted for mounting on a vehicle in a well known manner for transportation from place to place. Such vehicles are of a well-known type and carry power drive means for imparting the necessary movements to all movable parts of the apparatus of the present invention.

The frame or digging ladder 10 forms a framework or housing within which a conveyor belt 12 is disposed. A pulley or roller 14 for the conveyor belt 12 is rotatably mounted on a shaft 16 which is suitably supported on the frame 10. A housing or casing 18 is suitably secured in well known manner to the housing or framework formed by the frame 10, and is adapted to enclose a drive shaft 20, gearing 22 and a cross shaft 24. The drive shaft extends through and is rotatably supported by the frame 10, and is adapted, at the end thereof that is not shown, for connection with a power drive means for rotating the shaft 20 in a suitable manner. At its free end, the shaft 20 is connected with the cross shaft 24 through the gearing 22 to establish driving connection between the shafts 20 and 24. The gearing 22 may be of any desired construction or formation, but is shown as including a worm gear 26 fixedly secured to the free end of the drive shaft 20 and a gear 28 fixedly secured to the cross shaft 24 and meshing with the worm gear 26.

The cross shaft 24 is rotatably supported in the housing. 18.and extends to opposite sides of the housing. Wheels 30 and, 32 are secured to each end of the shaft 24 and are suitably secured to the shaft for rotation therewith by means of a key 34. Each of the wheels 30 and 32 comprise a hub portion 36 and a plurality of cutters, or cutting blades, 38 secured to the hub portion 36 and extending in a radial direction therefrom. The hub portions 36 have been shown as comprising octagonal drums, to each surface of which one blade 38 is suitably secured, as by welding, or the like. The use of a polygonal drum for the hub portions 36 is convenient, since such drums provide flat surfaces to which the blades 38 may be readily secured. It will be. apparent, however, that the hub portions 36 can be formed in any manner desired andmay constitute, for example, cylindrical plates rather than polygonal drums. Likewise, the cutters 38 are preferably formed separately from the hub portion 36 and suitably secured to the peripheral surfaces of the hub portion 36, but it will be apparent that the blades can be secured in any desired manner to the hub portions 36 and may, in fact, be formed integrally therewith.

As shown in Figures 1 and 2, the blades each present a leading edge 48 with the leading edge 4-0 of each of the blades being preferably sharpened to provide a cutting edge adapted to be moved against a bank of material. As shown in the drawings, the cutting blades 38 each comprise a plate of metal secured to the flat peripheral surfaces of the octagonal drum 36 and extending diagonally thereof. It will be appreciated, however, that the blades 33 can take any desired configuration, so long as the blades each present, according to the present invention, an inclined surface 42 extending from the blades leading edge it), which is adjacent the outer side of wheel hub 36, inwardly toward the inner side of the wheel hub 36. As is shown in Figure l, the blades 38 are preferably provided also with an inclined peripheral edge leading downwardly from the leading edge of the blade to the trailing edge thereof.

As shown in Figure l, the cutting blades 38 are adapted to effect a downward cutting action on the bank of material indicated in the drawings and the wheels 30 and 32 are rotated in a counterclockwise direction. As is shown in Figure 2, the excavating apparatus of the present invention is adapted to be moved transversely, that is, along the surface, of the bank of material to remove a layer of material from the bank, the blades 38 of one wheel effecting the cutting action. As will be ap reciated from Figure 2, the downward cutting action of the blades 38 of the wheel 32 forces the cut material into the space between the cutting wheels 30 and 32, and forces same downwardly in the direction of rotation of the cutting wheels in a manner to be described in greater detail hereinafter. A guide plate 44 is suitably secured, as by welding, to the lower portions of the frame 10 and extends into the space between the cutting wheels 30 and 32 at the lower portion thereof. As is clearly shown in Figure l, the guide plate 44 is positioned adjacent the periphery of the wheels 30 and 32 and is arcuately curved in a path generally conforming to the periphery of the wheels. The plate 44 terminates at its rearward end adjacent the upper run, or carrying surface, of the conveyor belt 12. The plate projects forwardly from its point of support into the space between the wheels to receive material from the space between the wheels and guide same onto the conveyor belt 12. The plate 44 may suit-- ably terminate at its forward end at the bottom of the apparatus, as is indicated at 45, or may be extended, as is indicated by dotted lines and the numeral 47, to a position adjacent the forward side of the apparatus. In the latter case, the plate is preferably supported by a bracket or bracket plate, such as that shown indotted' lines and indicated at 48, extending between the forward end of the plate 44 and the housing 18. The conveyor 12 extends toward the wheels 30 and 32 and terminates adjacent the periphery thereof and has its longitudinal axis extending parallel to the planes of the two wheels and centrally of the space between the wheels. The conveyor 12 is driven in any suitable manner and leads either directly to a point of disposal or to other conveyors or the like which eventually lead to a point of disposal.

In operation, the apparatus shown in the drawings and described hereinbefore is suitably supported and driven in the manner described hereinbefore. In addition, the frame 10 and associated apparatus may be suitably supported by a supporting beam structure or the like. The apparatus is moved into position so that the peripheral surfaces of the cutting blades 38 will engage the surface of the bank of material to be cut. As the wheels are rotated, I the supporting structure and the wheels are swung in a horizontal arc to move the cutting blades 38 of one wheel, for example, the wheel 32, into engagement with the bank of material to commence As the rotating cutting wheels traverse or move along the surface of the bank of material, the leading edges 430 of the cutting blades 38 on the wheel 32 cut away a layer of the bank of material. The blades 38 are so disposed with respect to one another and the rate of advancement of the wheel into the material of the bank is such that the material is cut up into relatively small pieces which are forced, by the inclined surfaces 42 of the blades 38, into the space between the wheels 30 and 32. Any large rocks or the like will not be fed through the blades, due to the spacing and disposition thereof. The inclined surfaces 42 of the blades 38 of the wheel 30 prevent the passage of cut material from the space between the wheels in a direction transverse to the wheels. The wall of the bank of material being out forms an end wall which, with the two wheels, defines a chamber within which the material cut by the one wheel is retained. Gravity, centrifugal force, peripheral speed of the cutting blades 38 and the impelling action of the inclined surfaces 42 of the blades 33 force the material within the chamber, defined hereinbefore, downwardly and toward the rearward portions of the cutting wheels.

guide plate is used, that is, plate terminates as at 45', the cut material, so forced downwardly and rearwardly, is forced onto the guide plate 44 and as further material is forced onto the guide plate, the material is moved rearwardly over the guide plate and onto the upper run or carrying surface of the conveyor belt 12. T he longer or extended plate, indicated at 47, is preferably utilized for the excavation of clay and like materials so that the same will fall directly on the guide plate and be forced rearwardly thereover to reduce the tendency of such materials to become stuck within the space between the wheels. In this respect, the bracket 48 preferably comprises a generally triangularly shaped metal plate intersecting the space between the wheels so that the same acts to break up the clods or masses of material being moved onto the guide plate. If desired, a plurality of spaced brackets or breaker plates may be employed. The conveyor belt 12 is driven in a suitable manner and, preferably, at substantially the same rate of speed as the speed of feed of material to the belt so that the belt need not accelerate the material. The travel of the carrying surface of the belt 12 is in the same direction as the direction of feed of material thereto so that the belt is not subjected to transverse strain and, accordingly, is adapted for continued and long service in the apparatus.

In the apparatus of the present invention, as shown in Figures 1 and 2 and as described hereinbefore, the forces of gravity, centrifugal force and peripheral speed cooperate to force the material cut by the cutting blades onto the conveyor. The dirt need not travel any substantial distance in being discharged from the space between the wheels or being discharged from the cutting blades and, accordingly, there is no necessity for providing a time delay for allowing the material to take the desired course. Therefore, the wheels may be operated at any desired speed and the device is not subjected to severe impact, as is the case in bucket wheel excavating apparatus, as described hereinbefore. Furthermore, the dirt being cut in passing over the blades 38 automatically performs a cleaning action thereon so that there is seldom any necessity for stopping the excavating apparatus to clean the same. The conveyor belt is not subjected to impact or transverse strain, nor is it required to accelerate the material fed thereto. Accordingly, the life of the conveyor belt is increased greatly over that of conveyors used with bucket wheel excavators. From the foregoing, it will be appreciated that the excavating apparatus of the present invention has greater capacity for excavation and removal of material for a given size than any bucket wheel cleaner of a comparable size, and, in fact, even greater than the capacity of bucket wheel excavators of substantially larger size.

The operation, described hereinbefore, continues until the frame It) has been moved to one limit of its horizontal swinging movement, or the cutting blades 38 of the wheel 32 become disengaged from the surface of the bank of material being cut. At such time, the frame 10 and cutting wheels 30 and 32 are advanced toward or into the bank of material so that the cutting blades 38 of the wheel 30 are moved into of a layer of material away from the wall of the bank of material. The frame 10 and wheels 30 and 32 are then swung in the opposite direction so that the blades 38 of the wheel 30 perform the cutting operations described hereinbefore with respect to the wheel 32, and the Wheel 32 assists in the material impelling operations described hereinbefore with respect to the wheel 30. In continued operation of the apparatus of the present invention then, the supporting frame 10 and wheels 30 and 32 are oscillated in a horizontal plane with respect to 30 and 32 are rotated to action, as described herein since a substantial portion of the weight of the apparatus and the weight of the material removed thereby may be directly supported upon the ground. This support may be obtained solely by the engagement of the peripheral surfaces of the blades 38 with the ground, or may be accomplished by support of the apparatus on the ground through the frame 10, or both.

From the foregoing, it will be appreciated that the present invention accomplishes the objects recited hereinbefore and provides, for a given capacity of material excavation, a much smaller apparatus than was heretofore regarded as possible. The apparatus also presents considerable economy in construction, as compared with the bucket wheel excavators heretofore used commercially. A further advantage is that the apparatus is self cleaning. Centrifugal action and gravity cooperate to discharge dirt, rather than opposing each other as in the bucket type wheel where the material is discharged radially inwardly of the wheel. Therefore, the apparatus presents considerable savings in time and expense of production and operation and its total excavating capacity over a period of time will greatly exceed that of bucket Wheel excavators larger than the excavating apparatus of the present invention.

Referring now to Figure 3, an embodiment of the present invention is shown wherein the cutting blades on the cutting wheels are adapted to effect a cutting action in an upward direction. The various elements and members of the embodiment of the invention shown in Figure 3 are substantially identical to the various elements and members of the embodiment of the invention shown in Figures 1 and 2, and, accordingly, similar or identical parts have been indicated by the same reference numerals with the sufiix a. While the parts and elements are substantially identical, the disposition thereof is, in effect, reversed from the disposition of the various parts and elements shown in Figures 1 and 2. In fact, the apparatus of Figure 3 may be accomplished simply by inverting the entire apparatus of Figures 1 and 2., with one exception, namely, the disposition of the guide plate 44a. Accordingly, it will be appreciated that Figure 2 can be considered as a top plan view of the apparatus shown in Figure 1 and as a bottom plan view of the apparatus shown in Figure 3. In the action of cutting upwardly, however, the guide plate must be repositioned, as is shown in Figure 3, to extend fully within the space between the cutting wheels and intersect that space so that the material forced in the direction of rotation by the wheels will feed the material onto the top of the guide plate 44a and over the plate onto the top or carrying surface of the conveyor 12a. In all instances, the guide plate extends between the rows of blades and toward the leading edges of the blades.

When cutting upwardly, the impelling action of the inclined surfaces of the blades 38a, centrifugal force and the peripheral speed of the blades must cooperate to overcome the force of gravity tending to prevent movement of material in the direction of rotation of the wheels. The wheels must, therefore, be operated at a speed sufficient to overcome the force of gravity on the material. When the wheels are rotated at slightly more than the speed required to move the material, the material will be moved, in substantially the same manner as described hereinbefore, around and onto the guide plate 44a. However, when the wheel is rotated at speeds substantially in excess of that required to overcome the force of gravity on the material, tne centrifugal force and peripheral speed may cooperate to throw the material upwardly a substantial distance so that same is not fed onto the conveyor 12a or is fed onto the conveyor 12a without passing over the guide plate 44a and with substantial impact. To prevent the occurrence of such conditions, the apparatus may be provided, in a customary manner, with a hood or shield 46 supported by frame 10a and extending over the upper portion of the wheels adjacent the periphery of the cutting blades to retain the material within the space between the cutting wheels, whereby same is forced onto and over the guide plate 44a to the conveyor 12a.

As pointed out hereinbefore, it is preferred that the apparatus of the present invention be operated to effect a downward cutting action so that a portion of the weight of the apparatus may be supported by the ground. The device is fully capable of use in performing an upward cutting action, as disclosed in Figure 3, but when subjected to such a use, the supporting structure for the cutting wheels must be made heavier than when the wheel is utilized in a downward cutting action since the support structure must bear the entire weight of the device plus the weight of the material being lifted.

From the foregoing, it will be appreciated that both embodiments of the invention provide improved excavating apparatus of simplified construction, which is subjected to less wear and impact, requires less repair and maintenance, and has increased capacity for any given size over bucket wheel excavators as used commercially. The embodiment of the invention shown in Figures 1 and 2 has certain advantages over the embodiment of the invention shown in Figure 3, but both embodiments of the invention overcome substantially all of the disadvantages of bucket wheel excavators, as outlined hereinbefore.

While I have shown what I regard to be preferred embodiments of my invention, it will be apparent that various modifications, changes and rearrangements can be made in the apparatus shown and described without departing from the scope of the present invention, as defined by the appended claims.

l claim:

1. Excavating apparatus comprising two rows of cutting blades, said rows being spaced apart, and means for moving said rows of bladcsin spaced planes, said cutting blades each being inclined to the plane of rotation thereot and including a leading edge disposed at the outboard side of the respective row, said leading edge of each blade constituting a cutting edge extending outwardly substantially from the base to the periphery of the blade and facing generally laterally of the respective row of blades to the outboard. side thereof.

2. Excavating apparatus comprising two rows of cuttors, and means for moving said rows, said cutters each including a cutting edge along one margin thereof extending substantially from the base of the respective cutter to the periphery thereof, said cutting edge of each cutter being disposed adjacent the outboard side of the respective row and comprising the leading edge of the cutter in the direction of movement of said rows, said cutters each including a surface facing toward the inboard side of the respective row inclined from said leading cutting edge thereof toward the other row, said cutting edges facing generally laterally of the respective row to the outboard side thereof to cut into material to be excavated upon movement of said rows transversely of the direction in which said rows are moved by said means, said inclined surface of each cutter forcing material cut by the cutting edge of the respective cutter into the space between said rows and in the direction in which said rows are moved by said means.

3. Excavating apparatus comprising two rows of cutting blades, said rows being spaced apart, and means for moving said rows of blades in spaced planes, said cutting blades each being inclined to the plane of rotation thereof and including a leading edge disposed at the outboard side of the respective row, said leading edge of each blade constituting a cutting edge extending outwardly substantially from the base to the periphery of the blade and facing generally laterally of the respective row of blades to the outboard side thereof to cut into material to be excavated upon movement of said rows generally transversely of the planes of movement thereof, the inwardly facing surface of each blade, due to the inclination of the blade to its plane of movement, being inclined from the leading edge of the blade toward the other row of blades to force material cut by the leading cutting edge of the blade into the space between said rows and in the direction of movement of said rows in said planes, and a guide plate extending into the space between said rows in the direction opposite the movement of said rows in said planes to receive thereon cut material forced in the direction of movement of said rows by said surfaces of said blades.

4. Excavating apparatus comprising two rows of cutting blades, said rows being spaced apart, means for moving said rows of blades in spaced planes, said cutting blades each being inclined to the plane of rotation thereof and including a leading edge disposed at the outboard side of the respective row, said leading edge of each blade constituting a cutting edge extending outwardly substantially from the base to the periphery of the blade and facing generally laterally of the respective row of blades to the outboard side thereof to cut into material to be excavated upon movement of said rows generally transversely of the planes of movement thereof, said blades, due to the inclination thereof, forcing material cut by the leading cutting edge of each blade into the space between said rows and in the direction of movement of said rows in said planes, and soil breaker mean in the space between said rows.

5. Excavating apparatus comprising a pair of spaced parallel wheels mounted for rotation about the same axis, means for rotating said wheels, and a plurality of outwardly extending cutters carried in a single row by each wheel, said cutters each including a cutting edge along one margin thereof extending substantially from the periphery of the respective wheel to the periphery of the cutter, said cutting edge of each cutter being disposed adjacent the outboard side of the respective wheel and comprising the leading edge of the cutter in the direction of wheel rotation, said cutting edges of the blades on each wheel lying generally in a common plane in the plane of rotation of the respective wheel, said cutters each including a surface facing toward the inboard side of the respective wheel inclined from said leading cutting edge thereof toward the other wheel, said'cutting edges facing generally laterally of the respective wheel to the outboard side thereof to cut into material to be excavated upon movement of said wheels transversely of the planes of rotation thereof, said inclined surface of each cutter forcing material cut by the cutting edge of the respective cutter into the space between said wheels and in the direction of wheel rotation.

6. Excavating apparatus comprising a pair of spaced parallel wheels mounted for rotation about the same axis, means for rotating said wheels, a plurality of outwardly extending cutters carried in a single row by each wheel, said cutters each including a cutting edge along one margin thereof extending substantially from the periphery of the respective wheel to the periphery of the cutter, said cutting edge of each cutter being disposed adjacent the outboard side of the respective wheel and comprising the leading edge of the cutter in the direction of wheel rotation, said cutters each including a surface facing toward the inboard side of the respective wheel inclined from said leading cutting edge thereof toward the other wheel, said cutting edges facing generally laterally of the respective wheel to the outboard side thereof to cut into material to be excavated upon movement of said wheels transversely of the planes of rotation thereof, said inclined surface of each cutter forcing material cut by the cutting edge of the respective cutter into the space between said wheels and in the direction of wheel rotation, a guide plate extending into the space between said wheels toward the leading edges of said cutters to receive thereon the material cut and moved by said blades, and at least one bracket supporting the forward end of said guide plate, said bracket intersecting the space between said wheels to break up the material between said wheels.

7. Excavating apparatus comprising a shaft, a pair of wheels, one wheel being mounted at each end of said shaft, means for rotating said shaft, each wheel comprising a hub portion and a plurality of cutting blades on said hub portion extending generally radially of said shaft, said blades each including a cutting edge along one margin thereof extending substantially from the periphery of said hub to the periphery of the blade, said cutting edge of each blade being disposed adjacent the outboard side of the respective wheel and comprising the leading edge of the blade to cut into the material to be excavated upon movement of said wheels transversely of the planes of rotation thereof, said cutting edges of the blades of each Wheel lying generally in a common plane parallel to the planes of rotation of said wheels, the cutting blades of each wheel each presenting a surface facing toward the inboard side of the respective wheel inclined with respect to the plane of wheel rotation from the leading edge of the blade toward the other wheel, a guide plate in the direction of wheel rotation, over said guide plate and onto the carrying surface of said conveyor.

8. A method of excavating material from a bank comprising the steps of moving a series of cutting blades in of the bank, directing the cut material laterally away from said blades, and wedging the cut material between each 10 blade and a laterally opposed member to move the cut material away from the bank.

9. A method of excavating material from a bank comprising the steps of moving a series of cutting blades in a vertical direction, disposing the blades with their bases adjacent the face of the bank, moving the series of blades horizontally across the face of the bank to cut a layer of material off the face of the bank, directing the cut mate rial laterally away from said blades in the direction opposite the direction of horizontal movement thereof toward a second series of blades moved in the same manner as and in horizontally spaced relation to the first series, and wedging the cut material between laterally opposed pairs of blades to move the cut material away from the bank.

10. A method of excavating material from a bank comprising the steps of rotating a first: series of cutting blades in a vertical direction, disposing the blades with their bases adjacent the face of the bank, sweeping the series of blades horizontally across the face of the bank to engage the blades with and surface of the bank to cut a layer of material off the face of the bank, rotating a second series of blades in the same manner as the first the cut material rearwardly and sidewardly with respect to the bank by the second series of blades toward the first series, and wedging the cut material between horizontally opposed pairs of blades to move the cut material rearwardly away from the bank.

11. A method of excavating material from a bank comprising the steps of moving a series of cutting blades in a predetermined path, disposing the blades with their bases adjacent the face of the bank, moving the series of blades laterally of said predetermined path across the face of the bank to cut a layer of material off the face of the bank, directing the cut material laterally away from said blades toward a laterally opposed member, confining cut material between said blades and member and the freshly exposed surfaces of the bank, and wedging the cut material between said blades and member to move the cut material away from the bank.

References Cited in the file of this patent UNITED STATES PATENTS 779,442 Richmond et al. Jan. 10, 1905 847,330 Grossmith Mar. 19, 1907 969,569 Smith et al. Sept. 6, 1910 1,588,563 Wilson June 15, 1926 1,593,523 Wright July 20, 1926 1,684,147 Roberts Sept. 11, 1928 2,153,719 Kuhsel Apr. 11, 1939 2,291,669 Weimer et al. Aug. 4, 1942 2,520,040 Levin Aug. 22, 1950 FOREIGN PATENTS 333,967 Germany Mar. 7, 1921 362,436 Germany Oct. 28, 1922 406,809 Germany Dec. 3, 1924 601,461 Germany Aug. 24, 1934 628,075 Germany Apr. 2, 1936 100,754 Great Britain July 6, 1916 360,395 Great Britain May 1, 1930

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