US3680919A

US3680919A - Excavating machine

Info

Publication number: US3680919A
Application number: US66226A
Authority: US
Inventors: Melvin K Rear; Robert L Greivell
Original assignee: American Hoist and Derrick Co
Current assignee: American Hoist and Derrick Co
Priority date: 1970-08-24
Filing date: 1970-08-24
Publication date: 1972-08-01
Anticipated expiration: 1989-08-01

Abstract

An excavating apparatus including a digging unit having an endless digging wheel adapted for digging in both hard and soft terrain. Weighted members are detachably mounted on the digging wheel for selectively controlling the inertia thereof for digging in hard terrain. A cleaning assembly is mounted on the digging unit for removing spoil adhering to the digging wheel when digging in soft terrain. The cleaning assembly includes a selectively adjustable deflector mechanism adapted for discharging such spoil to one or both sides of the digging unit, as desired. Retaining covers are mounted on the digging unit adjacent the lower end thereof to prevent a build-up of excavated spoil thereon.

Description

United States Patent Rear et a1.

[54] EXCAVATING MACHINE [72] Inventors: Melvin K. Rear, Chesterland; Robert L. Greivell, Chagrin Falls, both of Ohio [73] Assignee: American Hoist and Derrick Company, St. Paul, Minn.

[22] Filed: Aug. 24, 1970 [21] Appl. No.: 66,226

[56] References Cited UNITED STATES PATENTS 2,721,733 10/1955 Driehaus ..299/89X 7/1868 Jones ..51/169 51 Aug. 1, 1972 2,914,866 12/1959 Vanderberg et a1. ..37/97 3,067,533 12/1962 Howard ..37/94 1,472,563 10/1923 Loken ..37/94 Primary ExaminerErnest R. Purser Atl0rneyTeare, Teare & Sammon [5 7] ABSTRACT An excavating apparatus including a digging unit having an endless digging wheel adapted for digging in both hard and soft terrain. Weighted members are detachably mounted on the digging wheel for selectively controlling the inertia thereof for digging in hard terrain. A cleaning assembly is mounted on the digging unit for removing spoil adhering to the digging wheel when digging in soft terrain. The cleaning assembly includes a selectively adjustable deflector mechanism adapted for discharging such spoil to one or both sides of the digging unit, as desired. Retaining covers are mounted on the digging unit adjacent the lower end thereof to prevent a build-up of excavated spoil thereon.

22 Claims, 7 Drawing Figures PATENTEDAus 1 I972 3,680.91 9

sum 1 UF 2 mlmlmlmn m 1 mum'lm J Le Mum 4 IN VEN TORS Z2 MEL. V//\/ K. REAR BY ROBERT LGREI VELL 95m, 9 6 s A TTORNEYS PATENTEUAUG 1 m2 SHEET 2 OF 2 w n i4 Em F INVENTORS MELVIN K REAR ROBERT L.GF?/EVELL A TTORNE Y5 BACKGROUND OF THE INVENTION This invention relates in general to excavating apparatus, and more particularly, is directed to an improvement in such apparatus to enable digging in both soft and hard terrain. When digging in hard terrain, such as frozen ground, coral or the like, it is necessary that the digging wheel be of such construction to provide a sufiiciently high rotational inertia to enable the digging wheel to be maintained at a predetermined rotational speed. Usually, the .speed of rotation for digging in soft terrain is relatively higher than that for digging in hard terrain. When a machine having a relatively heavy digging wheel is employed for use in digging soft terrain, there is a tendency for the machine to become unbalanced, and thus, making it difficult for the operator to control the excavating machine, also when weights are used there is less room for spoil. In the past, various attempts have been made to overcome this condition, but these have not proven to be entirely satisfactory. For example, additional weight has been added to the stationary structure of the digging unit supporting the digging wheel, but this has been found to be unsatisfactory in that such weight must be transmitted through the supporting structure to the digging wheel resulting in increased wear and maintenance on the excavating machine. Therefore, it has been found desirable to construct a digging wheel which will be suitable for digging in both soft and hard terrain and obviate such problems.

SUMMARY OF THE INVENTION The present invention contemplates providing an excavating machine including a digging unit having a digging member adapted for digging in both hard and soft terrain. A flywheel means is detachably mounted on the digging member adapted for selectively controlling the inertia thereof. The flywheel means comprises a plurality of segmental weight members. The digging member comprises a wheel-like support member adapted for rotation in a generally vertical plane about its geometrical center, and the weight members are arranged in generally symmetrical relation adjacent the periphery thereof. In addition, the support member includes a relatively narrow web extending generally radially outwardly from the geometrical center thereof being adapted for supporting the weight members thereon. A cleaning means is mounted on the digging unit being adapted for removing spoil adhering to the support member when the weight members are removed therefrom. A selectively adjustable deflection assembly is supported on the digging unit to enable the spoil to be discharged to one or both sides thereof. The cleaning means includes scraper members detachably mounted on the digging unit. The scraper members are mounted in spaced relation with respect to one another to enable the support member to rotate therebetween, and thus, engage any spoil adhering thereon for removal therefrom. In addition, retaining covers are detachably mounted on the digging unit adjacent the lower end thereof to prevent spoil from adhering to the digging wheel'during operation thereof.

As can be seen from the foregoing arrangement, an excavating machine is provided which can be readily and easily converted for digging in either soft or hard terrain. Further, such arrangement prevents the digging wheel from becoming unbalanced during operation when digging in soft terrain, thus enabling the operator to maintain control of the excavating machine. In addition, when the soft terrain is in a damp or muddy condition, such is prevented from adhering to or is removed after adhering to the digging wheel so as not to interfere with the operation thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of the excavating apparatus of the present invention shown having the weighted members removed, and the scraper members in the installed position;

FIG. 2 is a side elevation view of the excavating apparatus illustrated in FIG. 1 showing the weighted members in the installed position, and the scraper members removed therefrom;

FIG. 3 is a cross-sectional view taken along the line 33 of FIG. 1;

FIG. 4 is a cross-sectional view taken along the line 4-4 of FIG. 2;

FIG. 5 is a cross-sectional view taken along the line 5-5 of FIG. 2;

FIG. 6 is a perspective view of one form of segmental weighted member which may be employed in the present invention; and

FIG. 7 is a perspective view of one form of scraper member which may be employed in the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The digging apparatus of the present invention is illustrated, generally at 2, as including a chassis 5 adapted for movement along the ground on traction treads 6. A digging unit 12 is supported on a boom 14 which is pivotally connected to the chassis 5, such as at 16, for movement in a generally vertical plane for raising and lowering the digging unit 12 between the storage and digging positions. The digging unit 12 includes an endless digging member or wheel 18 mounted for rolling engagement on rotatable members or

rollers

20, 22, and 24 for rotation in a generally vertical plane. The

rollers

20, 22 and 24 are supported in spaced relation from one another by

support struts

26 and 28 which are mounted on the boom 14. An endless drive chain 30 is operably connected between a drive sprocket 21 and the roller 22 to impart rotational movement to the digging wheel 18. Referring now to FIG. 2, when digging in hard terrain, such as frozen ground, coral or the like, a plurality of weighted members 46 may be provided which may be detachably mounted on the digging wheel 18 to increase the rotational inertia thereof, and thus, create a flywheel-like effect for maintaining the rotational speed of the digging wheel within a predetermined range. Referring now again to FIG. 1, when diggingin soft terrain, and more particularly terrain which is relatively damp or wet, a cleaning assembly 31 may be provided which may be mounted on the digging unit 12, and as shown, may include a plurality of scraper members 32 adapted for removing spoil which has adhered to the digging wheel during the excavating operation. As the spoil created while excavating in hard terrain will not normally adhere to the digging wheel, the weighted members 46 are necessarily removed from the digging wheel prior to the installation of the cleaning assembly 31. Retaining covers, such as at 25 may be mounted on the digging unit 12 on opposite sides of the digging wheel 18 being adapted to prevent spoil from adhering to and building up on those portions of the digging wheel not cleaned by the cleaning assembly.

Referring now to FIG. 4, the digging wheel 18 is shown as being generally rectangular in configuration, and when-viewed in radial transverse cross-section has a radially extending dimension substantially greater than its widthwise dimension. As shown, the digging wheel 18 comprises a pair of generally flat, ring-like plates 54 and 56 which may be mounted together in side-by-side relation. The plates 54 and 56 may be connected together in any suitable manner, but preferably are joined together in clamped relation along one edge, such as the inner edge, by a pair of generally circular, ring-

like base members

58 and 60 which are adapted for rolling engagementwith the

rollers

20, 22 and 24 in a manner well known in the art. The

base members

58 and 60 may be held together in such clamped position by suitable fasteners, such as rivets 62, which are mounted in spaced relation about the

base members

58 and 60. Further, each of the base members carries a plurality of tooth members, such as at 64, which are adapted for coacting engagement with gears, such as at 65, which are operably connected to the roller member 20 for imparting movement to the digging wheel as well known in the art.

Preferably, a pair of oppositely disposed flange-like rings 66 are mounted on the digging wheel 18 which project generally perpendicularly outwardly therefrom in opposite directions from one another being adapted to coact with the retainer covers 25 to retain spoil from entering the interior of the digging wheel. As shown, the rings 66 may be connected to the plates 54 and 56, respectively, in any suitable manner, such as by welding or the like. In the form shown, the retaining rings 66 are mounted radially outwardly from the inner edge of the digging wheel 18 in overlying relation to the teeth 64, and thus, also prevent spoil from adhering to and building up along the inner edge of the digging wheel adjacent the teeth 64 to prevent clogging of the spaces therebetween and interfere with the rolling contact of the inner edge with the

roller members

20, 22 and 24.

Preferably, a plurality of cutter members 40 are mounted in spaced relation along the outer periphery of the digging wheel 18. As shown, the cutter members 40 are generally T-shaped in configuration including a generally flat, horizontally extending support member 42 which is connected to the outer edge of the digging wheel 18 by means of a relatively thin, radially extending, web-like leg 44. Preferably, the support member 42 is angularly oriented with respect to the outer edge of the digging wheel 18 being adapted to scoop up the excavated material and throw it upwardly and outwardly from the trench formed duringthe excavating operation. As shown, each of the support members 42 is adapted for mounting a plurality of digger teeth, as at 43. Preferably, the teeth extend forwardly in a direction of rotation of the wheel and outwardly toward the opposite sides thereof being adapted to direct the excavated spoil toward the opposite sides of the digging wheel 18 as it is thrown up out of the excavated trench.

To selectively control the inertia of the digging wheel 18, the weighted members 46 may be mounted on one, but preferably are mounted on opposite sides of the digging wheel as shown in FIG. 4. Referring now to FIG. 6, each of the weighted members may be generally arcuate in configuration so as to conform generally to the configuration of the digging wheel when in the installed position. The weighted members 46 may be mounted in space relation about the digging wheel 18, but preferably are mounted in end-to-end relation to provide a more uniform distribution of the weight thereof, and thus, provide a better balance for the digging wheel 18. In the invention, only one pair of semi-circular, segmental members need be provided, but preferably six or more are provided to facilitate handling and installation of the same on the digging wheel. The weighted members 46 may be detachably mounted on the digging wheel in any suitable manner, but as shown, may be provided with a plurality of openings 52 disposed in predetermined spaced relation lengthwise thereof being adapted to receive suitable fasteners therethrough, such as bolts 48 adapted for threaded connection to a suitable connector, such as a nut or the like. Referring again to FIG. 4, the digging wheel may be provided with similarly spaced openings which are adapted for alignment with the openings 52 being adapted to receive the bolts 48 therethrough for securing the members 46 on the digging wheel 18.

Referring again'to FIG. 6, the segmental weighted members 46 are preferably of an elongated construction being defined by inner 45 and outer'47 edges. Preferably, each of the members 46 is generally rectangular in transverse cross-section having its major access extending generally parallel to the major access of the digging wheel 18. Preferably, the outer edge 47 of the members 46 is mounted in circumferential alignment with the outer edge of the digging member to take full advantage of the weight thereof when in the installed position (FIG. 4).

Referring now to FIG. 3, the cleaning assembly 31 comprises a pair of oppositely disposed scraper members 32 which are mounted on opposite sides of the digging wheel 18. As shown, the boom 14 may include a pair of laterally extending beams 15 which extend rearwardly from the chassis 6 along opposite sides of the digging wheel. A generally vertically oriented support plate 33 extends generally upwardly from the beams 15 being adapted to support the scraper members 32 thereon. As shown, the support plate 33 is pro vided with a generally T-shaped cutout portion 35 adjacent the upper end thereof being adapted to receive the upper portion of the digging wheel therein. Each of the scraper members 32 includes a blade-like scraper plates 36 which is angularly disposed with respect to the vertical plane of rotation of the digging wheel 18. Preferably, each of the plates 36 extends generally inwardly toward the digging wheel and forwardly in a direction opposite to the direction of movement of the digging wheel passing through the cutout portion 35. Each of the plates includes opposed inner edges 37 which extend generally parallel toward one another defining a slot 39 having a transverse width sufficient to enable the digging wheel 18 to pass therebetween when the weighter members 46 are not mounted thereon. The scraper plates 36 may be mounted on the support plate 33 in any suitable manner, but as shown, are supported, such as by welding or the like, adjacent the upper ends of support arms 34 which may be secured to the support plate 33 in any suitable manner, such as by bolts 38 or the like. Preferably, the edges 37 of the scraper plates 36 are offset with respect to the geometrical center of the digging wheel so as to be angularly oriented with respect to the direction of rotation thereof to provide a slight slicing action for facilitating removal of spoil adhering to the digging wheel. The support arms 34 may be made of any suitable material, such as angle iron or the like, and are preferably anchored in position by means of braces, such as at 41 which are connected at their upper end to the support arms 34 and at their lower end to the boom beams to provide a firm supporting structure for the scraper plates 36. By this arrangement, spoil adhering to the digging wheel will be continuously removed upon rotation of the digging wheel.

' Referring again to FIGS. 2 and 4, the retaining covers are preferably of a generally semi-circular configuration, and may be rigidly mounted on the digging unit in any suitable manner. Preferably, the retaining covers 25 include brackets 74 which are connected to the boom beams 15 and support struts 26 and 28 by suitable fasteners, such as bolts 76 or the like. By this arrangement, the covers 25 will remain relatively stationary during rotation of the digging wheel, and will close off the open center of the digging wheel 18 to prevent loose spoil from entering therein and building up adjacent the lower end of the digging wheel during the excavating operation. As shown in FIG. 4, the retaining plates 25 extend radially laterally alongside the digging unit in generally close proximity thereto having a sufficient transverse distance therebetween to enable rotation of the digging unit 18 in the space therebetween. Preferably, the covers 25 extend radially outwardly terminating adjacent the retaining rings 66 thereby defining a chamber 68 which encloses the lower half of the digging wheel; By this arrangement, the'rings 66 coact with the covers 25 adjacent the inner side of the chamber to prevent and/or minimize the entrance and build-up of spoil within the interior portion of the digging wheel as defined by the rings 66.

When digging in extremely damp or muddy terrain, a supplementary cleaning assembly 69 may beprovided as shown in FIGS. 1 and 5. The cleaning assembly 69 includes a pair of oppositely disposed scraper members 70 having blade-like scraper plates 72 similar to the plates 36 of the scraper rnembesr 32. Preferably, the plates 72 include substantially parallel cutting edges 73 which are oriented in a generally horizontal direction so as to remove any extremely damp or muddy spoil adhering to the digging unit before it begins its movement along the upper portion of the digging unit. This has been found necessary as most of the loosely clinging muddy or damp spoil will drop off of the digging unit before contacting the scraper plates 36, and thus, very likely fall into the space between the retaining covers 25. As shown, the plates 72 may be attached to the retaining covers 25 by support arms 78 which may be secured thereto by suitable fasteners, such as bolts 75 or the like. Preferably, the retaining covers are cut out, as at 77 to enable the plates 72 to extend inwardly into close proximity adjacent the digging wheel 18 providing a sufficient space therebetween to enable the digging wheel to rotate freely without contacting the opposed edges 73. As previously stated, the covers 25 extend radially outwardly having their marginal edges 77 disposed adjacent the ring 66 to close off the chamber 68, and thus, prevent the damp or muddy spoil from entering the chamber 68. As damp or muddy spoil can readily be removed from the digging wheel, the edges 73 mayextend generally perpendicular with respect to the direction of movement of the digging wheel in contrast to the angular orientation specified with respect to the edges 37 of the scraper plates 36.

A deflecting mechanism 90 is operably associated with the cleaning assembly 31 to distribute the spoil removed from the digging wheel 18 to one or both sides of the digging unit. In the form shown, the deflecting mechanism comprises deflecting

members

92 and 94 which may be pivotally mounted on a generally horizontally extending support rod 96 which is mounted on the support plate 33. As shown, the rod 96 projects generally perpendicularly and forwardly from the plate 33 with the

plates

92,94 being adapted for swinging movement in a generally vertical direction about the horizontal axis of the rod 96, as indicated by the arrows 97. In the normal operating, that is, when discharging spoil to both sides of the digging unit, the deflecting

members

92 and 94 are supported in an inclined position by brackets 98 so as to extend generally outwardly and downwardly from the rod 96. As shown, the longitudinal central axis of the rod 96 extends substantially within the plane defined by the major transverse axis of the digging member 18 so that spoil removed therefrom will be distributed evenly between the

members

92 and 94 when it adheres uniformly to the digging wheel 18. An auxiliary bracket 99 may be provided which is adapted for mounting on the support plate 33 being adapted to support the plate 92 in a raised angular position for discharging spoil removed from the digging wheel to one side of the digging unit. Preferably, when in the raised position, the upper surface 102 of the plate 92 is generally coextensive with the upper surface of the plate 94. As both

plates

92 and 94 are free to pivot about the support rod 96, the plate 92 may remain in the lowered position and the plate 94 may be raised so as to have the upper surface 104 thereof form an upper extension for the upper surface 102 of the plate 92 for discharging the spoil removed from the digging wheel to the opposite side of the digging unit, when desired.

We claim: 1. In an excavating machine including, a chassis, a digging unit mounted on said chassis for rotational digging movement thereon, said digging unit including an endless digging member having a plurality of cutter members mounted thereon and projecting outwardly therefrom, flywheel means for varying the inertia of said digging unit and maintaining the rotational speed of said digging member, said flywheel means including a plurality of weight members, and said weight members each being detachably connected to said digging member for selective connection or removal from said digging member to control the inertia and rotational speed thereof in accordance with the consistency and hardness of the terrain being excavated.

2. In an excavating machine in accordance with claim 1, wherein said digging member being defined by a circular outer periphery in side elevation, and

said weight members are mounted on said digging member adjacent said outer periphery being generally arcuate-shaped in side elevation so as to generally conform to the peripheral shape of said digging member when in the installed position thereon.

3. In an excavating machine in accordance with claim 1, including selectively adjustable deflection means adapted for discharging excavated material to one or both sides of said digging unit.

4. In an excavating machine in accordance with claim 1, wherein said digging member comprises an endless, wheellike support member adapted for rotation about a generally horizontal axis, and

said weight members are detachably mounted in symmetrical relationship on said support member.

5. In an excavating machine in accordance with claim 4, wherein said weight members are mounted in substantially end-to-end relation adjacent the periphery of said support member.

6. In an excavating machine in accordance with claim 4, wherein said support member is of a generally ring-like construction, and

the cross sectional area defined by a plane extending radially through said support member has the greatest transverse dimension in the radial direction.

7. In an excavating machine in accordance with claim 4, wherein said weight members are mounted on at least one side of said support member.

8. In an excavating machine in accordance with claim 4, wherein said support member includes a base adapted for mounting said support member on said digging unit, and

a relatively flat ring extending outwardly from said base adapted for mounting said weight members thereon.

9. In. an excavating machine in accordance with claim 8, wherein said cutter members include a digger tooth mounted adjacent the outer end thereof, and

said digger tooth is connected to said support member by a relatively thin web-like arm.

10. In an excavating machine in accordance with claim 1, including retaining means mounted on said digging unit adapted to retain excavated material outwardly of said digging unit.

11. In an excavating machine in accordance with claim 10, wherein said digging member is of a ring-like construction having an open center, and

said retaining means comprises a pair of spaced,

retaining plates mounted on said digging unit on opposite sides of said digging member being positioned radially inwardly thereof for enclosing the open center to prevent spoil from entering therein.

12. In an excavating machine in accordance with claim 11, wherein said plate members are rigidly mounted on said digging unit, and

said digging member rotates relative to said plate members.

13. In an excavating machine in accordance with claim 1, including scraper means adapted for mounting on said digging unit, and

said scraper means adapted for removing soil adhering to said digging member when said flywheel means is removed therefrom.

14. In an excavating machine in accordance with claim 13, wherein said scraper means includes a pair of detachable scraper assemblies mounted on opposite sides of said digging member,

said scraper assemblies each including a scraper member extending inwardly toward said digging member into the position formerly occupied by said weight members when installed on said digging member, and

said scraper member being mounted in stationary relation on said digging unit to enable said digging member to move relative thereto upon rotation thereof for removing excavated spoil adhering to said digging member.

15. 'In an excavating machine in accordance with claim 13, including selectively adjustable deflection means for discharging spoil scraped from said digger member by said scraper means to the side of said digging unit,

said deflection means including a pair of deflection plates pivotally mounted on said digging unit, and

support means on said digging unit for supporting said deflection plates in a lowered angular position for discharging said excavated spoil to both sides of said digging unit or one of said deflection plates in a raised angular position and the other of said deflection plates in a lower angular position for discharging said spoil to one side of said digging unit.

16. In an excavating machine in accordance with claim 13, wherein said scraper means includes at least one pair of v generally vertically-oriented scraper members and at least one pair of generally horizontally-oriented scraper members rigidly mounted on said digging unit,

a deflection assembly mounted on said digging unit below said vertically-oriented scraper members for discharging spoil scraped from said digging member outwardly away from said digging unit,

the retaining means mounted on said digging unit adapted to retain excavated material outwardly of said digging unit,

said retaining means comprising a pair of retaining plates mounted on opposite sides of said digging member, and

said horizontally-oriented scraper members are mounted on said digging unit forwardly of said vertically-oriented scraper members for scraping spoil from said digging member to prevent said spoil from entering the space between said retaining plates before reaching said vertically-oriented scraper members.

tion when viewed in side elevation for covering the lower portion of said digging member. 18. A scraper apparatus for use in an excavating machine having a digging unit including an endless digging member adapted for rotation in a generally vertical plane about a horizontal axis, comprising at least one pair of oppositely disposed scraper assemblies mounted on said digging unit and projecting inwardly toward one another,

said scraper assemblies each including a scraper member extending inwardly toward said digging member for removing spoil adhering to said digging member,

a selectively adjustable deflection mechanism mounted on said digging unit for discharging excavated spoil away from said digging unit,

said deflection mechanism including a pair of deflection plates pivotally mounted on said digging unit, and

support means on said digging unit for supporting said deflection plate in a lowered angular position for discharging said excavated spoil to both sides of said digging unit or supporting one of said deflection plates in a raised angular position and the other of said deflection plates in a lowered angular position for discharging spoil to one side of said digging unit.

19. A scraper apparatus in accordance with claim 18,

wherein said excavating machine includes retaining means comprising a pair of spaced, retaining plates mounted on said digging unit on opposite sides of said digging member, and

another pair of scraper assemblies mounted on said digging unit on opposite sides of said digging member for scraping spoil from said digging member prior to removal of said spoil from said digging member by said one pair of scraper assemblies to prevent said spoil from entering into the space between said retaining plates.

20. A scraper apparatus in accordance with claim 19,

wherein each of said scraper members include oppositely disposed edges spaced from one another a distance sufficient to enable movement of said digging member therebetween.

21. A scraper apparatus in accordance with claim 19,

wherein said scraper members of said one pair of scraper assemblies are disposed in a generally vertically-.

oriented position and said scraper members of said other pair of scraper assemblies are disposed in a generally horizontally-oriented position in the normal digging position of said digger member.

22. A scraper apparatus in accordance with claim 21,

wherein members.

Claims

1. In an excavating machine including, a chassis, a digging unit mounted on said chassis for rotational digging movement thereon, said digging unit including an endless digging member having a plurality of cutter members mounted thereon and projecting outwardly therefrom, flywheel means for varying the inertia of said digging unit and maintaining the rotational speed of said digging member, said flywheel means including a plurality of weight members, and said weight members each being detachably connected to said digging member for selective connection or removal from said digging member to control the inertia and rotational speed thereof in accordance with the consistency and hardness of the terrain being excavated.

2. In an excavating machine in accordance with claim 1, wherein said digging member being defined by a circular outer periphery in side elevation, and said weight members are mounted on said digging member adjacent said outer periphery being generally arcuate-shaped in side elevation so as to generally conform to the peripheral shape of said digging member when in the installed position thereon.

4. In an excavating machine in accordance with claim 1, wherein said digging member comprises an endless, wheel-like support member adapted for rotation about a generally horizontal axis, and said weight members are detachably mounted in symmetrical relationship on said support member.

6. In an excavating machine in accordance with claim 4, wherein said support member is of a generally ring-like construction, and the cross sectional area defined by a plane extending radially through said support member has the greatest transverse dimension in the radial direction.

8. In an excavating machine in accordance with claim 4, wherein said support member includes a base adapted for mounting said support member on said digging unit, and a relatively flat ring extending outwardly from said base adapted for mounting said weight members thereon.

9. In an excavating machine in accordance with claim 8, wherein said cutter members include a digger tooth mounted adjacent the outer end thereof, and said digger tooth is connected to said support member by a relatively thin web-like arm.

11. In an excavating machine in accordance with claim 10, wherein said digging member is of a ring-like construction having an open center, and said retaining means comprises a pair of spaced, retaining plates mounted on said digging unit on opposite sides of said digging member being positioned radially inwardly thereof for enclosing the open center to prevent spoil from entering therEin.

12. In an excavating machine in accordance with claim 11, wherein said plate members are rigidly mounted on said digging unit, and said digging member rotates relative to said plate members.

13. In an excavating machine in accordance with claim 1, including scraper means adapted for mounting on said digging unit, and said scraper means adapted for removing soil adhering to said digging member when said flywheel means is removed therefrom.

14. In an excavating machine in accordance with claim 13, wherein said scraper means includes a pair of detachable scraper assemblies mounted on opposite sides of said digging member, said scraper assemblies each including a scraper member extending inwardly toward said digging member into the position formerly occupied by said weight members when installed on said digging member, and said scraper member being mounted in stationary relation on said digging unit to enable said digging member to move relative thereto upon rotation thereof for removing excavated spoil adhering to said digging member.

15. In an excavating machine in accordance with claim 13, including selectively adjustable deflection means for discharging spoil scraped from said digger member by said scraper means to the side of said digging unit, said deflection means including a pair of deflection plates pivotally mounted on said digging unit, and support means on said digging unit for supporting said deflection plates in a lowered angular position for discharging said excavated spoil to both sides of said digging unit or one of said deflection plates in a raised angular position and the other of said deflection plates in a lower angular position for discharging said spoil to one side of said digging unit.

16. In an excavating machine in accordance with claim 13, wherein said scraper means includes at least one pair of generally vertically-oriented scraper members and at least one pair of generally horizontally-oriented scraper members rigidly mounted on said digging unit, a deflection assembly mounted on said digging unit below said vertically-oriented scraper members for discharging spoil scraped from said digging member outwardly away from said digging unit, the retaining means mounted on said digging unit adapted to retain excavated material outwardly of said digging unit, said retaining means comprising a pair of retaining plates mounted on opposite sides of said digging member, and said horizontally-oriented scraper members are mounted on said digging unit forwardly of said vertically-oriented scraper members for scraping spoil from said digging member to prevent said spoil from entering the space between said retaining plates before reaching said vertically-oriented scraper members.

17. In an excavating machine in accordance with claim 16 wherein said retaining plates are semi-circular in configuration when viewed in side elevation for covering the lower portion of said digging member.

18. A scraper apparatus for use in an excavating machine having a digging unit including an endless digging member adapted for rotation in a generally vertical plane about a horizontal axis, comprising at least one pair of oppositely disposed scraper assemblies mounted on said digging unit and projecting inwardly toward one another, said scraper assemblies each including a scraper member extending inwardly toward said digging member for removing spoil adhering to said digging member, a selectively adjustable deflection mechanism mounted on said digging unit for discharging excavated spoil away from said digging unit, said deflection mechanism including a pair of deflection plates pivotally mounted on said digging unit, and support means on said digging unit for supporting said deflection plate in a lowered angular position for discharging said excavated spoil to both sides of said digging unit or supporting one of said deflection plates in a raised angular position and the other of said deflection plates in a lowered angular position for discharging spoil to one side of said digging unit.

19. A scraper apparatus in accordance with claim 18, wherein said excavating machine includes retaining means comprising a pair of spaced, retaining plates mounted on said digging unit on opposite sides of said digging member, and another pair of scraper assemblies mounted on said digging unit on opposite sides of said digging member for scraping spoil from said digging member prior to removal of said spoil from said digging member by said one pair of scraper assemblies to prevent said spoil from entering into the space between said retaining plates.

20. A scraper apparatus in accordance with claim 19, wherein each of said scraper members include oppositely disposed edges spaced from one another a distance sufficient to enable movement of said digging member therebetween.

21. A scraper apparatus in accordance with claim 19, wherein said scraper members of said one pair of scraper assemblies are disposed in a generally vertically-oriented position and said scraper members of said other pair of scraper assemblies are disposed in a generally horizontally-oriented position in the normal digging position of said digger member.

22. A scraper apparatus in accordance with claim 21, wherein said horizontally-oriented scraper members are mounted on said digging unit forwardly of said vertically-oriented scraper members so that said horizontally-oriented scraper members remove spoil from said digger member prior to any removal of spoil by said vertically-oriented scraper members.