US2840937A

US2840937A - Excavating apparatus

Info

Publication number: US2840937A
Application number: US599778A
Authority: US
Inventors: Jr Forbes R Clarke
Original assignee: UNITED ELECTRIC COAL Cos
Current assignee: UNITED ELECTRIC COAL Cos
Priority date: 1956-07-24
Filing date: 1956-07-24
Publication date: 1958-07-01
Anticipated expiration: 1975-07-01

Description

July 1, 1958 F. R. CLARKE, JR 2,840,937

EXCAVATING APPARATUS Filed July 24, 1956 2 Sheets-Sheet 1 IN V EN TOR.

F. R. CLARKE, JR

EXCAVATING APPARATUS July 1, 1958 2 Sheets-Sheet 2 Filed July 24, 1956 F H INVENTOR. J BY I i United States Patent 2,84%,937 Patented July 1, 1958 ice EXCAVATING APPARATUS Forbes R. Clarke, Jr., Du Quoin, 11L, assignor to The United Electric Coal Companies, (Chicago, 111., a cerporation of Delaware Application July 24, 1956, Serial No. 599,778

3 Claims. (Cl. 37-189) The present invention relates to improvements in excavating apparatus, and particularly, to improvements in excavating apparatus of the character disclosed in the Patent Nos. 2,757,462 and 2,757,463, both issued on August 7, 1956, and both assigned to the assignee of the present application.

In excavating apparatus of the character referred to, an excavating wheel including two spaced parallel rows of cutting blades is rotated and simultaneously moved horizontally sideward into a bank of earth material to effect excavation. Each blade has a generally radially extending leading edge disposed adjacent the outboard side of the wheel and an inner side surface inclined from the leading edge of the blade toward the other row. As the wheel is rotated and moved sidewardly in the manner defined, the leading edges of the blades in the leading row cut material from the bank and the inclined surfaces thereof move the excavated material into the space between the rows. The inclined surfaces of the blades in the other row and the face of the bank being excavated retain the excavated material in the space between the rows, and the said inclined surfaces of the blades in both rows force the excavated material in the direction of wheel rotation to deliver the material onto a discharge conveyor extending rearwardly from the wheel.

In practice, the excavating capacity of the apparatus above described was not as great as may have been expected and manners of increasing capacity were sought. In this connection, it was proposed, as described and claimed in said Patent No. 2,757,462, to provide a plurality of radially extending fingers between corresponding blades in-the two rows. However, this proposal has not been an optimum solution and has resulted in additional problems, including clogging of material in the space between the blades and necessity for frequent repair of the fingers.

It is the object of the present invention to provide improved auxiliary earth moving means for apparatus of the character defined overcoming the disadvantages of the said prior proposal and assisting the blades to a substantial extent in discharging excavated material from the space between the blades.

Another object of the invention is to provide improved mounting means for said auxiliary earth moving means facilitating convenient installation, repair and replacement of the auxiliary earth moving means, affording longevity of service and preventing damage to the earth moving means in the event of excessive load.

A particular object of the invention is the provision of an improved auxiliary earth moving member, in the form preferably of a chain, extending laterally between the trailing edges of corresponding blades in the two rows adjacent but spaced from the peripheral edges of the blades to break up excavated material in the space between the rows and to assist the blades in moving excavated material in the direction of movement of the rows.

A further object of the invention is the provision of an improved auxiliary earth moving member as defined and an improved mounting therefor including a connection at one end of the member of less strength in shear than the member itself, so that the member is not destroyed upon occurrence of excessive load.

Other and more specific objects and advantages of the invention will become apparent in the following detailed description of a preferred embodiment of the invention.

Now, in order to acquaint those skilled in the art with the manner of making and using the excavating apparatus of the invention, I shall describe, in connection with the accompanying drawings, a preferred embodiment of the invention and a preferred manner of making and using the same.

In the drawings:

Figure 1 is a fragmentary side elevation of excavating apparatus of the type to which the present invention relates;

Figure 2 is a plan view, on an enlarged scale, of a pair of blades and my improved material impelling auxiliary earth moving means; and

Figure 3 is a fragmentary side elevation of the earth moving means shown in Figure 2.

Referring now to the drawings, and particularly to Figure 1, the apparatus to which the invention relates is shown as including a frame or digging ladder 10 carrying a rotatable digging or excavating wheel 26 at the outer end thereof. As is known, the ladder 10 is adapted to be pivotally supported on a vehicle for horizontal and vertical swinging movement and for transportation from place to place, the vehicle including means supporting the ladder and carrying power drive means for imparting the necessary movements to all movable parts of the apparatus.

The digging wheel 26 may be mounted for rotation in various manners on the ladder 10, and is provided with outboard drive means which may be disposed at either or both sides of the wheel. By way of example, in the structure disclosed herein, the digging ladder 10 includes a pair of spaced parallel beams 12 supporting a drive motor 14 and a speed reducer 16. The speed reducer 16 includes a drive shaft 18 rotatably supported at its ends by bearings 20 mounted on the beams 12. At the outer end thereof, each beam 12 is provided with a bearing block 22 rotatably supporting a digging wheel shaft 24 in spaced parallel relation to the shaft 18. The digging wheel 26 is mounted on the shaft 24 for rotation therewith and includes two spaced rows of cutting blades or cutters 30 each including a leading edge 32 disposed at the outboard side of the respective row of blades and an inwardly facing surface 34 inclined from the leading edge of the respective blade toward the other row of blades. At one side thereof, wheel 26 is spaced from the adjacent beam 12 to accommodate the mounting of a plurality of sprockets 36 on the shaft 24. A like number of sprockets 38 are mounted on the drive shaft 18 in alignment with the sprockets 36, and chains 40 are reeved over aligned pairs of the sprockets 36 and 38 to provide a drive connection or power transmission between the motor 14 and the excavating wheel. While a chain drive at one side of the wheel is shown herein as satisfactory, it will be appreciated that other drive means of a known nature may be provided at either or both sides of the wheel.

The digging ladder 10 includes a plurality of struts 42 extending downwardly therefrom to support a conveyor belt 44% and its associated frame 46. The conveyor 44 is conventional in form with the upper run thereof comprising the material carrying surface. The conveyor is of a Width substantially equal to the distance between the two rows of cutting blades 30 and is supported with its end disposed immediately to the rear of the blades to receive material cut thereby.

In the embodiment illustrated, the cutting blades Sil are adapted to effect a downward cutting action on a bank of material, the wheel 26 being rotatable in a counterclockwise direction. With the excavating wheel rotated in this direction, a guide plate 48 is suitably secured, as by welding, to the forward portions of the conveyor frame 46 and extends into the space between the two rows of cutting blades at the lower portions thereof. The guide plate 48 is positioned adjacent the periphery of the cutting wheels and is arcuately curved in a path generally conforming to the periphery of the blades. The plate 43 terminates at its rearward end adjacent the upper run of the conveyor belt 44 to direct material cut and moved by the blades from the space between the wheels onto the belt. The belt 44 is driven by suitable means (not shown) to convey the excavated material to a point of discharge.

In operation, the excavating wheel 26 is rotated in the manner described and the digging ladder and the apparatus carried thereby are supported to be moved horizontally and vertically. The apparatus is moved into position so that the peripheral edges of the cutting blades 4 are disposed adjacent the face of a bank of material to be excavated. As the excavating wheel is rotated, the ladder 10 is swung in one direction in a horizontal arc to move the cutting blades in the leading row sidewardly into engagement with the bank of material to commence a cut. The leading edges 32 of the cutting blades 36 in the leading row cut into the bank to remove material therefrom, the blades 30 being so disposed with respect to one another and the rate of advancement of the wheel into the bank being such that the material is cut up into relatively small pieces which are forced, by the inclined surfaces 34 of the blades 30, into the space between the wheels. The inclined surfaces 34 of the blades 30 in the other or trailing row prevent the passage of cut material from the space between the wheels in a direction transverse to the wheels. The wall of the bank being excavated forms an end wall which, with the two wheels, defines a chamber receiving the material cut from the bank by the blades of the leading row. Gravity, centrifugal force, the peripheral speed of the cutting blades 30 and the impelling action of the inclined surfaces 34- of the blades force the material within the said chamber downwardly and toward the rearward portions of the excavating wheel. The cut material is thus forced by the inclined surfaces of the blades onto and over the guide plate 48 and thence onto the upper run or carrying surface of the conveyor belt 44, which conveys the excavated material to a convenient point of discharge.

The above described action continues until the ladder 10 has been moved to one limit of its horizontal swinging movement, or the cutting blades in the leading row become disengaged from the surface of the bank of material being excavated. At such time, the ladder 10 and the excavating wheel are advanced inwardly into the bank so that the cutting blades 30 in the other row are moved into position to effect a cut. The ladder 10 and excavating wheel 26 are then swung horizontally in the opposite direction so that the blades in the said other row Will perform the cutting operation above described and the blades in the first-named row will assist in the material impelling or moving function previously described. In continued operation of the apparatus, the digging ladder 10 and the excavating wheel 26 are oscillated in a horizontal plane with respect to the bank of material being excavated, with the wheel being advanced toward the bank at the end of each swinging stroke. The ladder 10 may also be lowered or raised to position the wheel for horizontal oscillation at different levels, to accommodate excavation over a wide area of the face of the bank.

While express reference has been made hereinbefore to operation of the device in such manner that the cutting blades effect a downward cut, it will be appreciated that the blades may be operated in the opposite direction so as to effect an upward cut, as has been described in said Patent No. 2,757,463.

Referring more particularly to Figures 2 and 3, the present invention affords improvements in apparatus of the character above described by providing improved auxiliary earth moving means extending laterally between cor 'esponding blades in the two rows for assisting the excavating or main blades 30 in the functions of breaking up the excavated material and conveying the material in the direction of wheel rotation. in the drawings, particularly Figures 2 and 3, I have shown my auxiliary earth moving means associated with the improved blades and blade sets described and claimed in the copending application of Frank P. Kolbe, Serial No. 599,804, filed July 24, 1956. For a detailed description of the blades, blade sets and their mounting, reference is made to said application. I

According to the present invention, my improved auxiliary earth moving means comprises a narrow member, preferably flexible, extending transversely between aligned or paired main blades in the two rows at the trailing edges of the blade and adjacent the peripheral edges thereof. The said member is preferably a chain but may suitably comprise a rigid bar or the like, a length of wire rope or cable. I prefer the chain as being most effective and least troublesome, and a chain is shown in the accompanying drawings as constituting the preferred embodiment of the invention.

The location of the auxiliary earth moving member is quite critical, as is its area. Specifically, if the entire space between transversely aligned blades in the two rows were closed at the trailing edges of the blades by means of a plate or a plurality of fingers, the space between the two blades would rapidly become clogged with excavated earth materials and the blade means would carry the excavated earth around past the discharge point at the guide plate 48 and back over the top of the wheel so that the excavating capacity of the wheel would be very rapidly reduced to such extent as to render wheel operation impractical. Moreover, even if only one or two members were disposed between corresponding blades in the two rows, and said members included portions extending adjacent the periphery of the cylindrical surface of the wheel per se, the tendency for material to clog between the blades would still be so pronounced as to render the auxiliary earth moving means impractical. In particular, even if a single auxiliary earth moving member were extended transversely between corresponding blades adjacent the periphery of the cylindrical drum or wheel, clogging would occur to a highly objectionable degree. on the other hand, the auxiliary earth moving means tends to lose material impelling effectiveness in proportion generally to its spacing from the peripheral surface of the wheel per se. According to the present invention, I prefer to employ a single auxiliary earth moving member extending transversely between corresponding blades in the two rows, the member being spaced substantially from the periphery of the wheel per se and being spaced inwardly a relatively short distance from the peripheral edges of the blades at the trailing edges thereof. This structure aifords the distinct advantages of eliminating clogging and yet affording a member appreciably assisting in the material impelling functions of the excavating blades. The auxiliary earth moving member moreover passes in close proximity to the guide plate 48 to perform a scraping function relative thereto to prevent excess accumulation of material on the guide plate.

In a specific preferred embodiment of the present invention, clevis means 50, in the form preferably of a pair of spaced parallel plates 52 having aligned apertures therein, are secured, suitably by welding, to the trailing edge of each blade 30 adjacent but spaced inwardly from the peripheral edge of the blade. The clevis means 50 on each pair of aligned blades are adapted for reception between the plates thereof of the end links of a chain 54. The chain 54, as originally installed, preferably is of a length to extend relatively tautly between the blades 39, and the chain is detachably secured at its opposite ends to the clevis means by bolts or like fasteners 55. The chain or other auxiliary earth moving member is thus adapted to be installed and replaced conveniently and rapidly.

A flexible auxiliary earth moving member, such as a chain or cable, affords advantages in apparatus of the character defined in that the same is adapted to yield, and after. periods of use to stretch, so that the same is well adapted to withstand shock loads imparted thereto and is capable of assuming a shape most advantageous for the above described functions of the auxiliary means.

With respect to the imposition of shock loads on the auxiliary earth moving member 54, the present invention affords an improved mounting for said member so that the same will not be damaged when excessive load is applied thereto. Specifically, at least one connection of the auxiliary earth moving member 54 to the excavating blades 30 is so formed as to have less strength in shear than the member itself, so that when the auxiliary earth moving member is subjected to excessive load, the said connection will be sheared before damage is sustained by the auxiliary member. In the preferred embodiment disclosed herein, the improved mounting of the chain 54 is accomplished by provision of at least one bolt 56 of a diameter less than that of the material of the chain to accommodate shearing of the bolt rather than breaking of the chain when the chain is subjected to excessive load.

in a practical physical embodiment of excavating apparatus of the character defined, the excavating blades 3% are each approximately 3 feet long and 26 inches high. Aligned or paired blades in the two rows are preferably spaced apart approximately 4 /2 feet at the forward edges of the teeth thereof, approximately 3 /3 feet at the leading edges of their main plates, and approximately 2% feet at the trailing edges of the blades. With such blades, the chain 54 to be employed is preferably a one inch high test steel chain approximately two feet eight inches long in the original installation. The blades, due to a step in the peripheral edge thereof, are approximately 22 inches high at their trailing edges and a clevis means 5% is preferably secured to the trailing edge of each blade at a point approximately 4 inches inward from the peripheral edge of the blade. The plates 52 of each clevis are of a size and strength to withstand shear stress well in excess 3f the shear strength of the bolts 56 employed. in the :onstruction specified, the material of the chain 54 is apiroximately one inch in diameter, and to mount the chain 11 accordance with the present invention, one of the bolts 56 is preferably a 4; inch diameter bolt, and the other :olt has a diameter of inch, the latter bolt being the irst element of the assembly to shear upon application of xcessive load to the chain.

i In use, when the excavating wheel is'rotated and one ow of blades 3% is advanced sidewardly into the bank of aaterial to be excavated, the transversely extending hains 5d engage the material forced into the space beween the two rows of blades and assist in moving the ma- :rial onto the conveyor 44, the chains also acting to reak up any large chunks of material between the two aws of excavating blades and to perform a cleaning funcon relative to the guide plate 48 so that excavated ma- :rial is continuously forced onto the conveyor. In the vent an excessive load is applied to one of the chains, he of the mounting bolts 56 therefor is adapted to shear r l I l l l 6 to prevent breaking of the chain, the other bolt retaining the chain on the wheel to prevent loss of the chain and to accommodate ready reassembly thereof.

in view of the foregoing, it is to be appreciated that the auxiliary earth moving means of the present invention affords marked advantages in apparatus of the character defined and appreciably increases excavating capacity, first, by assisting in the material irnpelling functions of the blades, and second, by maintaining the guide plate clean. The improved mounting for the auxiliary member enhances its usefulness and convenience and insures longevity of service.

While I have shown and described what I regard to be a preferred embodiment of my invention, it is to be appreciated that various changes, rearrangements and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

I claim:

1. For use in an excavating machine having two spaced rows of earth-cutting blades rotatable in vertical planes about a common horizontal axis and swingable as a unit in a horizontal path, with each row including a plurality of circumferentially spaced blades and with each of said blades including a generally radial leading edge disposed adjacent the outboard side of the respective row and including an inwardly facing surface inclined from the leading edge of the blade toward the other row of blades to force material cut by the rotating blades into the space between said rows and in the direction of rotation thereof, and with the blades in the two rows being of the same number and being paired generally transversely of the planes of rotation of said rows, the improvement comprising auxiliary earth moving means assisting the inclined surfaces of said blades in moving the earth cut by said blades in the direction of movement of said blades, said means being a narrow member extending between a pair of transversely spaced blades at their trailing edges and adjacent the periphery of said blades.

2. For use in an excavating machine having two spaced rows of earth-cutting blades rotatable in vertical planes about a common horizontal axis and swingable as a unit in a horizontal path, with each row including a plurality of circumferentially spaced blades and with each of said blades including a generally radial leading edge disposed adjacent the outboard side of the respective row and including an inwardly facing surface inclined from the leading edge of the blade toward the other row of blades to force material cut by the rotating blades into the space between said rows and in the direction of rotation thereof, and with the blades in the two rows being of the same number and being paired generally transversely of the planes of rotation of said rows, the improvement comprising auxiliary earth moving means assisting the inclined surfaces of said blades in moving the earth cut by said blades in the direction of movement of said blades, said means being a chain, fastening means secured at the rear edges of each pair of transversely spaced blades for detachably and pivotally connecting the ends of the chain to the respective blades adjacent the periphery of said blades.

3. The machine of claim 2 fasteners associated with each shear than said chain.

wherein at least one of the chain has less strength in References Cited in the file of this patent UNITED STATES PATENTS 1,666,841 Auspitzer Apr. 17, 1928 1,710,781 Mills Apr. 30, 1929 2,731,742 Johansson Jan. 24, 1956