US2910274A - Excavating apparatus - Google Patents

Description

Oct. 27, 1959 L.-F. SCOTT I 2,910,274

EXCAVATING APPARATUS Filed June 7, 1956 4 Sheets-Sheet 1 INVENTOR.

Oct. 27, 1959 sco v 2,910,274

VEXCAVATING APPARATUS Filed June 7, 1956 4 sheet -shed 2 a I ea? ATTOR 'Y Oct. 27, 1959 F. SCOTT 2,910,274

' EXCAVATING APPARATUS Filed June 7, 1956 4 Sheets-Sheet 3 INVENTOR.

AOAFf/V I? @6077 ATTOR/V'li? Oct. 27, 1959 L.'F. scoTT- 2,910,274

EXCAVATING APPARATUS Filed June 7, 1956 4 Sheets-Sheet 4 INVENTOR.

(ORE/V E SCOTT This invention relates to excavating apparatus and more particularly to a machine for digging holes for pouring bell-shaped footings,

In my prior Patent No. 2,743,904, dated May 1, 1956, there is disclosed a machine for digging bell-shaped foot in gs which, in use, has proved to be very successful. The

United States Patent machine of the present invention is generally of the type disclosed in my prior patent but incorporates improved features which make the present machine even more desirable than the machine of my prior patent.

It is an object of the present invention to provide a machine for digging holes for bell-shaped footings which is designed so that the bucket of the machine can be enlarged to a relatively great diameter in relation to the .Closed size of the bucket so that a hole having a relatively large undercut beneath the ground surface can be readily excavated.

Another object of this invention is to provide a machine that is admirably adapted for digging bell-shaped footing holes with flat base surfaces.

A further object of the invention is to provide a ma chine of the above described type that can be readily collapsed to a compact size for shipment wtihout any dismantling of the machine.

A further object of the invention is to provide a-ma chine of the above described type that is equally adaptable for drilling'vertical holes as well as holes inclined operative position and showing the manner in which it is operated to dig bell-shaped footing holes.

Fig. 2a is a fragmentary side elevational view showing the bucket of the machine in the dumping position.

Fig. 3 is a fragmentary side elevational view of the column of the machine.

Fig. 4 is a fragmentary side elevational view of the lower portion of the column of the machine as viewed in right angles to the showing in Fig. 3.

Fig. 5 .is a sectional View taken along the lines 5-5 in Fig. 3 and showing the manner in which the column is supported from the boom of the machine.

Fig. 6 is a sectional view taken along the lines 6-6 in Fig. 3 and showing generally the bucket supporting structure.

Fig. 7 is a sectional view taken along the lines 7-7 in Fig. 3.

Fig. 8 is a sectional view taken along the lines 8--8 in Fig. 3 and showing the door construction for the bottom portion of the bucket.

Fig. 9 is a vertical sectional view taken along the lines I 9- 9 in Fig. 3.

'end' of column section a.

Patented Oct. 27, 1959 ice Fig. 11 is a sectional view taken along the lines 11-11 in Fig. 9.

Fig. 12 is a diagram showing the fluid circuit of the machine. i Fig. 13 is a wiring diagram showing the electrical circuit of themachine.

The invention generally comprises a column assembly that is adapted for mounting on the boom of a basic crane unit. Referring to Fig. l, a conventional crane is shown at 10 which includes a cab 12 mounted for horizontal swinging movement on a base provided with caterpillar tracks 14. A power unit 16 Within the cab provides the motive power for the crane, such as' for swinging the cab, actuating the tracks 14 and operating the various reel drums within the cab. The boom 18 is pivotally connected to the cab platform as at 20 and is arranged to be elevated and lowered by means of a boom cable 22 connected to the boom as at 24, extending rearwardly to the cab over the guide pulley 26 and wound on the power reel 28. At its free end, boom 18 is fashioned with a pair of arms 30 (Figs. 3 and 5) on which are mounted bearing brackets 32. A gimbal ring 34 has a pair of diametrically opposite pins 36 journalled in bearing brackets 32. A circular plate 38 reinforced on its underside by a peripheral flange 40 has a pair of diametrically opposed pins 42 rigidly mounted thereon. The free ends of pins 42 are journalled within brackets 44 mounted on ring 34 and spaced circumferentially from pins 42. Thus, plate 38 is-mounted for universal pivotal movement at the end of boom 18. Plate 38 is centrally apertured for receiving an upper column 46. Column 46is fashioned as a steel tube and has four structural angles 48 extending vertically on the outer surface thereof. The angles 48 provide the outer surface of the tube with a generally rectangular shape. On the top side of plate 38, four rollers 50 are mounted for engaging two of the angles 48;

and on the bottom side of plate 38 are mounted another four rollers 52 for engaging the other two angles 48 on column 46. Thus, column 46 is guided for vertical movement through plate 38; and because of the gimbal ring mounting described, column 46 is adapted for universal pivoting movement relative to the boom.

Referring now to Fig. 9, it will be observed that the lower. end of column 46 has a collar 54 fixed thereon.

A bearing assembly 56 is bolted to the underside of collar 54. Bearing assembly 56 comprises a tubular sleeve 58 having upper and lower tapered bearing races 60 and 62 mounted therein. To the upper end of tube 58, there is clamped a plate 64; and to the lower end,

there is clamped a plate 66. Upper plate 64 (Fig. ll)

comprises two sections 68 and '70 secured together by bolts 72. Lower plate 66 (Figs. 7 and 9) is similarly formed as. two sections 74 and 76 clamped around the lower end of sleeve 58 by means of bolts 78. Within sleeve 58, there is arranged a lower column member '80 comprising two axially aligned sections 8tia and 80b and having bearing races. 82 and 84 thereon. Roller bearings 86 are arranged between the respective races on sleeve 58 and column member 84 to journal the column member 80 for rotation on a vertical axis below the lower end of upper column member 46. A jamb nut 88 is threaded to the upper end of column member 80a for adjusting the hearings to the desired fit. Below the lower race 82 on column member 86a, there is arranged a collar 99; and oil seals 92 are arranged between sleeve 58 and jamb nut 88 in collar 90. Lower plate 66 provides a supporting platform for a hydraulic motor 94 which, through a gear reduction 96, drives a pinion 98. Pinion 98 meshes with a pinion 1G0 keyed to the lower Column section 80b has a collar 102 Welded to the upper end thereof, and this collar is secured as by bolts 104 to the hub 10'6 of pinion 100. A shroud 108 on bottom plate 66 encloses pinions 98 and 100. The hydraulic motor 94 and gear reduction 96 provide the drive for lower column member 80. With this arrangement, when motor 94 is actuated, lower column member 8% is rotated about a vertical axis while the upper column member 46 remains stationary.

Referring now to Figs. 2, 3, 4, 7 and 9, the means for raising and lowering the column assembly comprises a cable 110 wound around a reel 112 in cab 12 and extending around a guide pulley 114 at the end of boom 18 and then downwardly around a pair of pulleys 116 mounted on and below lower plate 66 and then upwardly to plate 38 where the free end is anchored as at 118. When cable 110 is wound up on reel 112, the whole column assembly is shifted vertically upwardly as guided by rollers 50 and 52 on plate 38.

Lower column 80 supports a bucket assembly 120.

The column section 80b is split longitudinally to provide diametrically opposite vertical slots 122 (Fig. 6) and has a pair of angles 124 welded thereto on each side of the slots 122. At its lower end, column section 80b is provided with a fixed collar 126 and below collar 126, column section 80b is fitted with an auger 128. Links 130 have their lower ends pivotally supported on collar 126 as at 132. The upper ends of links 130 are pivotally mounted on bucket 134 as at 136. Bucket 134 is of cylindrical shape and is split axially into two half sections 134a and 13412. One of the links 130 has its upper ends pivotally connected to the bucket section 134a and the other link 130 has its upper ends pivotally supported on the bucket section 13411. Each bucket section has a pair of arms 138 welded thereto as at 140 and extending upwardly therefrom as shown in Fig. 3. Each set of arms 138 is reinforced by braces 142 and 144. At their upper ends, arms 138 are pivotally connected as at 146 to a support assembly 147. Assembly 147 includes a top plate 148 comprising two sections 150* and 152. Plate 148 has a plurality of vertically extending, radially arranged spacer plates 154 welded to the underside thereof; and to the lower ends of spacer plates 154, there is welded a second support plate 156. An anchor plate 158 which extends through the slots .122 in lower column section 801) is connected to aligned pairs of spacer plates 154 by means of bolts 16!) (Fig. 6). The support assembly 147 which comprises support plates 148 and 156 is guided for vertical movement on the two angles 124 by means of rollers 162 mounted on support plate 148 and rollers 164 mounted on lower support plate 156.

The means for raising and lowering this assembly is shown in Fig. 9 and comprises a cylinder 166 pivotally supported as at 168 within upper column member 46. Within cylinder 166 is arranged a piston 170 to which is connected a piston rod 172. The lower end ofpiston rod 172 extends downwardly through bearing assembly 56 and has a swivel connection as at 174 with a rod 176. Rod 176 extends downwardly through lower column member 8017 and supports anchor plate 158 at its lower end. Thus, as the piston 170 moves vertically within cylinder 166, support assembly 147 is moved vertically of lower column member 80b and at the same time, when motor 94 is actuated, anchor plate 158 provides a driving connection between lower column member 80b and support assembly 147 which in turn rotates the bucket.

As pointed out previously, the bucket itself comprises two sections 134a and 1341:. Each of these sections is semi-cylindrical in shape and its side wall is provided with openings 178 having cutting blades 180 secured to the trailing side of the openings so that when the bucket is rotated, the earth that is cut away by the blades 180 falls into the bucket through the openings 178. The openings 178 and blades 180 are staggered on the two sections of the bucket so that in effect they extend throughout the vertical extent of the bucket. 1 Each.

bucket section has the lower portionthereof cut away angularly as at 182 so that when the bucket is open as shown in broken lines in Fig. 2, the edges 182 are generally parallel to the base of the hole being excavated.

The upper end of bucket 134 is substantially open while the lower end of the bucket is provided with a door assembly mounted on collar 126 at the lower end of column section b (Fig. 8). Collar 126 has a pair of diametrically opposed radially extending arms 184 mount ed thereon. Each armis reinforced by an angular plate 186 at the rear side thereof; and on the forward side of each arm in relation to the direction of rotation of the bucket, there is arranged a cutting blade 188. Cutting blades 188 are angularly inclined as shown in Fig. 3 and are provided with teeth members 190 which extend downwardly to about the level of the ends of the lowermost blades on the side wall of the bucket. On each reinforcing angular plate 186, there is hinged about a horizontal axis as at 192 a bottom door member 194. Each bottom door member 194 extends around collar 126 less than 180 and has an auxiliary bottom door member 196 hinged thereto as at 198. As is best illustrated in Fig. 8, it will be observed that each bottom door 194 and its associated auxiliary section 196 extends substantially around 180 of collar 126. The auxiliary door sections 196 are hinged to the sections 194 so that they can pivot upwardly as shown in broken lines in Fig. 10 and downwardly to a substantially horizontal'position. The pivotal movement of doors 194 about hinges 192 are controlled by chains 200 which are attached at their upper ends to lower support plate 156 of support assembly 147 and at their lower ends to the door sections 194 as at "282. With this arrangement, it will be observed that when support assembly 147 moves downwardly on lower column member 801'; to open bucket 134, doors 194 pivot downwardly to the open position shown in Fig. 2a; and when support assembly 147 moves upwardly on column section 8% to the position shown in Figs. 3 and 4, doors 194 are pivoted upwardly to the closed position by chains 200.

In order to provide bucket 134 with a substantially continuous cylindrical wall when the bucket is closed, arcuate plates 204 generally of triangular shape are welded one to each of the radial rms 184. Plates 204 generally close the opening at each side of the bucket defined by theinclined edges 182 of the two bucket sections. In addition, there is provided at the outer end of each blade 188 a small arcuate scraper blade 206.

In soft, sticky clay, there may be a tendency for the clay excavated to hang as a mass and remain on the bottom door structure described. To insure discharge of substantially all the dirt excavated from the bucket, there is provided a pair of pushers 288 rigidly suspended from lower plate 156 of support assembly 147 by means ofbraces 210.and 212. Pushers 203 are disposed one at each side of lower column section 8% and are fashioned with inclined faces 214 that are arranged to move down with support assembly 147 to bodily push the dirt or clay oil of doors 194 when the bucket is opened (Fig. 2a).

The motive fluid for motor 94 and hydraulic cylinder 166 is provided by a pump 216 in the cab 12 of the crane unit. The fluid circuit of the machine is shown in Fig. 12. Pump 216 connects through a manually operated shut-off valve 218 in the cab 12 with the inlet of hydraulic motor 94 by means of a pressure supply conduit 220. The outlet side of motor 94 connects with a solenoid actuated pressure relief valve 222 which in turn connects with the exhaust line 224 back to the reservoir of pump 216. A bypass conduit 226 between valve 218 and motor 94 connects with a four-way solenoid valve 228. The exhaust side of valve 228 has exhaust conduit 224 connected thereto. One pressure port of solenoid valve 228 connects as by a conduit 230 with .the lower end of cylinder 166 and the other pressure port or solenoid valve 228 connects with the upper end of cylinder 166 as by conduit 232. 5

The electrical circuit for controlling the actuation ofvalves 222 and 228 is shown in .Fig. 13. This circuit includes a battery 234 having a pair of normally open spring biased switches 236 and 238 in circuit with one side thereof. Switch 236 is connected with one side of solenoid 240 of valve 228 and to one side of solenoid 242 of valve 222. Switch 238 is connected to one side of the other solenoid 244 of valve 228. The other sides of these solenoids connect with the other side of battery 23.4 as shown. Solenoid 240, when energized, is arranged to direct pressure fluid through conduit 230 to close the bucket; and solenoid 244, when energized, is arranged to :direct pressure fluid through conduit 232 to open the bucket. Solenoid 242, when energized, closes relief valve ;222,. The solenoid actuated pressure relief valve 222, when closed, insures sufiicient back pressure in line 226 foclose'the bucket when it is rotating rather freely without substantial resistance.

Referring now to Figs. 1 and 2, the pressure conduit 220 and the exhaust conduit 224- as well as the electrical leads from battery 234 (notshown in Figs. 1 and 2) extend from the cab 12 around a three-sheave pulley 246 down along upper column 46 to their respective components. To eliminate the necessity for reeling and unreeling these conduits and electric cable, pulley 246 is suspended from one end of a cable 248 which wraps around a pulley 250 supported by arms 252 at the upper end of column 46. Cable 248 extends downwardly through column 46 and has a counterweight 254 connected to the other end thereof. With this arrangement, as the column 46 is raised and lowered, pulley 246 lowers and raises so as to take up the slack in these conduits and electric cable.

In digging a bell-shaped footing with the machine of this invention, the crane unit is located such that the auger 128 is .disposed at the center of the hole to be excavated. B y reason of the gimbal support between the endof boom 18 and column46, column 46 will be vertically disposed unless it is intentionally shifted to an angular inclination.

When the auger 128 is located at the proper point, -two way valve 218 is actuated to direct pressure fluid to motor 94 and the bucket 134 is caused to rotate. As the bucket rotates, reel 112 is slowly unwound to pay out cable 110 and thus permit the bucket assembly to descend. As the bucket rotates and descends, the blades 188 at the lower end of the bucket and the blades 180 around the side wall' of the bucket dig into the earth and form a cylindrical hole- When the bucket is filled, its rotation is stopped and reel 1 12 is actuated to elevate the bucket out of the ground. The boom 18 isthen swung to one side to a position where the dirt in the bucket can be discharged. The bucket is opened by actuating switch 238 which, as explained previously, causes pressure fluid to be directed to the upper end of cylinder 166. Piston 170 is thus caused to move downwardly, and this in turn shifts the support assembly 147' on which the arms 138 are pivoted downwardly. This causes a jackknifing of. arm 138, and links 130 to swing the bucket sections 134a and 134b apart and thereby open. At the same time, since support assembly 147 moves downwardly, doors 194 swing downwardly to dischange the dirt supported thereon. As support assembly 147 moves downwardly, dirt pushers 208 also travel downwardly to forceably discharge any dirt remaining on doors 194- (see Fig. 2a). When the cylindric al hole designated 256 has obtained the depth desired, the operator may then start to bell out the bucket while it is rotating. This produces the bell-shaped excavation 258 at the lower end of the cylindrical hole 256. The inclined side wall of this bell-shaped excavation is formed by the" blades 180 at the sides of the bucket and the bottom wall of this bell-shaped excavation is cutby the blades 188 as well as the lowermost blades 180 on the side wall of the bucket sections.

One of the features of the present invention resides in the linkage construction, namely, the links 130 and arms 138 that are designed such that as the half sections of the bucket bell-out, the lower edges of the lowermost blades 180 travel in substantially a'horizontal path, thus insuring For example, a bucket having a diameter of 3 wherethe links .130 are 3'1" in length and the distance between the pivots 146 of arms 138 and the pivots 136 on the bucket and the distance is 29 /2" with the bucket closed can 'be belled out to a diameter of about 11'6". Further.- more, with the dimensions proportioned as described, when the bucket is belled outwardly, the lower edges of the lowermost blades 1801 011 the sides of the bucket travel radially outwardly in a generally horizontal plane without shifting the column assembly vertically. Thus, even though the operator is not in a position to see the bottom of the hole being excavated, he is assured that the bottom of the hole will be generally flat. Furthermore, it will be .appreciated. that the cylindrical hole 256 is not limited in size to the closed diameter of the bucket. The size of hole 256 is limited to the maximum diameter to which the bucket can be opened.

It will be observed that the hydraulic motor 94 and the associated components lie within the cylindrical surface defined by the bucket 134 when closed. Thus, the whole drive assembly for the bucket can be lowered into the hole being excavated. When this fact is coupled with the fact .that the column 46 can'be lowered to a position wherein its extreme upper end is engaged by rollers 50 and that the boom 18 can belowered to a position inclined downwardly to the horizontal, it will be appreci-. ated that the depth of the hole to be excavated can be almost as great as the length of the column assembly. This is also made possible, of course, by the gimbal support between the column assembly and the end of the boom. As an example, in a machine such as shown in the'drawings Where the length or" the column assembly from the. upper end of column 46 to the lower edge of the bucket 134 is 31', ,a hole having a depth of 30 can be readily excavated.

Another feature of the machine of this invention has to do with the construction which enables it to be col lapsed to a relatively compact size for transporting the machine from one location to another without in any way dismantling it. The machine in condition for transporting is shown in Fig. 1. Boom 18 is lowered to a generally horizontal position as shown by means of boom cable 22 and at the same time, the column assembly is pivoted to a position tucked beneath the boom by means of a crowd line 268 which connects with arms 138 as 18 and wraps around a reel 272. With the column as sembly in the position shown in Fig. 1 wherein the bucket 134 is disposed below the boom 18 and just forwardly of the caterpillar tracks 14, itwill be observed that the upper end of column 46 extends forwardly a relatively short distance beyond the forward end of boom 18.

Thus, the machine can be collapsed to a relatively compact size and thenecessity for removing the column assembly from the boom is eliminated when it becomes necessary to transport the machine from one location to another.

I claim:

1. In an excavating apparatus, the combination of a support, a vertically extending column on said support, a generally cylindrical bucket mounted for rotation adja cent the lower end of said column, said lower end of the column terminating adjacent the lower end of said bucket, said bucket being split axially into two half sections, a'vertically shiftablejzsupport on said column, each of said bucketsections having an arm thereon pivotally con nected to said vertically shiftable support, a link pivotally connecting each of said bucket sections with said lower end of said column whereby when said last mentioned support is shifted vertically downwardly, said arms and links swing the two bucket sections bodily outwardly;

2. The combination set forth in claim 1 wherein said arms and links are related in length and angularity with respect to one another such that when said last mentioned support is shifted vertically downwardly, the lower opposite edge portions of the two bucket sections swing out wardly in a generally horizontal plane.

3. The combination set forth in claim 1 including a bot tom door structure for said bucket and means operatively connecting said bottom door structure with said vertically shiftable support for opening and closing said bottom door structure in response to vertical movement of said last mentioned support.

4. In an excavating apparatus, the combination of a support, a vertically extending column on said support, a generally cylindrical bucket at the lower end of said column, said bucket being split axially into two half sections, a cylinder on said column having a piston rod projecting downwardly towards said bucket, a pair of arms fixed one on each of said bucket sections, said arms extending upwardly above the upper end of the bucket and pivotally connected at their upper ends to said piston rod for swinging in a vertical plane, a pair of links pivotally connected at one end to the lower end of said column and pivotally connected at their opposite ends one to each of said bucket sections for swinging in a vertical plane whereby as said piston rod is projected downwardly and retracted, said arms and links cause said bucket sections to swing bodily outwardly to opened and inwardly to closed positions, respectively, said arms extending upwardly above said bucket a distance at least generally equal to the vertical extent of said bucket, the lower end of said column terminating adjacent the lower end of said bucket and a door structure for the lower end of the bucket hinged to the lower end of said column, said door structure including downwardly swingable door sections and actuating means interconnecting said door sections with said piston rod whereby said door sections are permitted to swing downwardly to facilitate discharge of the bucket when the bucket sections are swung to open position.

5. The combination set forth in claim 4 wherein said actuating means for said door sections comprise collapsible tension members.

6. In an excavating apparatus, the combination of a support, a vertical column on said support, said column comprising an upper section non-rotatably mounted on said support and a lower section rotatably mounted on the upper section, drive means on the upper section for rotating said lower section, a generally cylindrical bucket supported adjacent the lower end of said lower column section, said lower column section terminating adjacent the lower end of said bucket, said bucket being split axially into two half sections, means movable axially of said lower column section above the bucket and forming a pivot support for said two bucket sections, arms on said bucket connected with said pivot support and link means pivotally connected at one end with each of said bucket sections and pivotally connected at the opposite end with the lower end portion of said column whereby when said pivot support is moved downwardly, said bucket sections swing outwardly to open and when said pivot support is moved upwardly, said bucket sections swing inwardly to closed position.

7. The combination set forth in claim 6 wherein said pivot support, said arms and said link meansare related such that the lower opposite edge portions of the two bucket sections swing outwardly in a substantially horizontal plane when said pivot support is agtuated vertically of said lower column sectionwhilethe lower column section is in vertically fixed position.

8. The combination set forth in claim '6' including a cylinder supported on said upper column section having a piston rod projecting downwardly towards said bucket, said pivot support being connected with said piston rod for movement therewith.

9. The combination set forth in claim 6 including a cylinder supported on said upper column section having a piston rod projecting downwardly towards said bucket, said pivot support being rotatable with said lower column section and having a swivel connection with said piston rod. V

10. The combination set forth'in claim 6 wherein said lower column section is provided with axially extending diametrically opposed slots, said pivot support including a plate within said lower column section extending outwardly through and movable axially within said slots so as to be rotated "by said lower column section.

11. In an excavating apparatus, the combination of a support, a vertical column on said support, said column comprising an upper section non-rotatably mounted on said support and a lower section rotatably mounted on the upper section, drive means on the upper section for rotating said lower section, a generally cylindrical bucket supported adjacent the lower end of said lower column section, said bucket being split axially into two half sections, each of said bucket sections including an arm fixed thereon and extending upwardly thereof, said lower column section extending downwardly into the bucket and terminating adjacent the lower end thereof, said lower column section having a vertically shiftable support thereon above the bucket, said armsconverging upwardly toward and being pivotally supported at their upper ends on said last mentioned support'and a pair of links pivotally connected at one end to each of said bucket sec tions and converging downwardly with the opposite ends pivotally connected with the lower end portion of said lower column section.

12, The combination set forth in claim 11 wherein each bucket section is provided with cutting blades on the outer side thereof, one of said blades on each bucket section being disposed adjacent the lower edge thereof and diametrically opposite the corresponding blade on the other bucket section.

13. The combination set forth in claim 12 wherein said arms and said link means are related in length and angularity with respect to one another such that when said vertically shiftable pivot moves downwardly on said lower column section and said lower column section is held in vertically fixed position, said opposite blades at the lower edges of said two bucketsections move outwardly in a substantially horizontal plane.

14. The combination set forth in claim 11 including a door structure for said bucket mounted at the lower end of said lower column section, said door structure providing a bottom wall for said bucket when said bucket sections are in closed position, said door structure includingdoor sections adapted to swing downwardly to facilitate discharge of the contents of the bucket and means extending between and forming a linkage interconnecting said door sections with said vertically 'shiftable support for actuating said doors in response to raising and lowering of said vertically shiftable support.

15. The combination set forth in claim 14 wherein said door structure includes a pair of radially extending plates fixed adjacent the lower end of said lower column section, said door sections being hinged to said radially extending plates. 7

16. In an excavating apparatus, the combination of a support, a vertically extending column on said support, a generally cylindrical bucket at the lower end of said column, said bucket being split axially into two half sections, a cylinder on said column having a piston rod projectipg downwardly towards said bucket, each of said bucket sections having an arm extending upwardly therefrom and pivotally connected at its upper endto said piston rod, a pair of links pivotally connected at one end to the lower end of said column and pivotally connected at their opposite ends one to each of said bucket sections whereby as said piston rod is projected downwardly and retracted, said arms and links cause said bucket sections to swing bodily outwardly to opened and inwardly to closed positions, respectively, and including a member connected to said piston rod and extending downwardly into said bucket whereby when said piston rod moves downwardly to open the bucket, said member moves downwardly through the bucket, said member having means at the lower end thereof engageable with the dirt in the bucket to displace it downwardly and out of the lower end of the bucket when said member is moved downwardly through the bucket.

17. In an excavating apparatus, the combination of a support, a vertical column on said support, said column comprising an upper section non-rotatably mounted on said support and a lower section rotatably mounted on the upper section, drive means on the upper section for rotating said lower section, a generally cylindrical bucket supported adjacent the lower end of said lower column section, said bucket being split axially into two half sections, each of said bucket sections including an arm fixed thereon and extending upwardly thereof, said lower column section having a vertically shiftable support thereon above the bucket, said arms converging upwardly toward and being pivotally supported at their upper ends on said last mentioned support and a pair of links pivotally connected at one end to each of said bucket sections and converging downwardly with the opposite ends pivotally connected with the lower end portion of said lower column section, and including a dirt pusher comprising a member suspended from said vertically shiftable support and movable downwardly into the bucket in response to downward movement of said last mentioned support, said last mentioned member providing a means for pushing the contents of the bucket downwardly out the lower end thereof.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Apr, 25, 1956

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