US1887101A - Dredge - Google Patents

Description

NOV. 8, 1932. w MAC'AULAY I 1,887,101

DREDGE Filed Aug. 2. 1930 3 Sheets-Sheet 1 INVENTOR. Wo/zer A7 Macau/ag A TTORNEYS.

Nov. 8, 1932. w. B. MACAULAY ,8

' DREDGE Filed Aug. 2. 1930 3 Sheets-Sheet 2 IN V EN TOR.

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Nov. 8, 1932.

W. B. MACAULAY DREDGE 5 Sheets-Sheet 3 Filed Aug. 2. 1950 U, 0 mm n 7 Z r W.. B h

Patented Nov. 8, 1932 UNITE-DTYV'ST'ATES' PATIENT" oFF1cE WALTER B MAOAULAY, F OAKLAND, CALIFORNIA, ASSIGNOR TO YUBA. MANUFAC- TUBING COMPANY, or

1 01mm 1 1 I SAN FRANCISCO, CALIFORNIA, CORPORATION OF CALI- manner Application flled Au gust 2, 1930; Serial No. 472,562.

My invention relates to bucket .dredges especially of the type provided with a digging ladder and a conveyor. 7

It is customary in the use of such dredges to float them on a body of Water either natural or artificial and to lower the digging ladder below the surface of the water and against the material to bedredged. A line of buckets on the ladder is operated to convey the material 0 through the water and above the level of the water to discharge onto the barge portion of the dredge. Dredges of this character are usually of considerable size and the ladder which supports the entire line of buckets is relatively large and massive. I, Necessarily therefore the auxiliary construction for supporting and maneuvering the ladder is of relatively great size and weight. In the past considerable difficulty has been encountered dredged when carried by the buckets along the upper side of the ladder is prone to spill over and discharge onto the ladder itself. Although some of'such discharged material falls clear of the ladder and some additional portion eventually is dislodged, nevertheless, a considerable amount of such material remains on the ladder. The material thus deposited not only increases the weight of the ladder tremendously thereby necessitating extra strong construction and support but also in numerous instances interferes with any auxilary mechanism which may be supported on the ladder, such as for instance, rollers for supporting the upper run of the line of buckets. Attempts have heretofore been made to discharge such accumulated material by means of a stream of water flowing from 40 the upper end of the inclined ladder toward the lower end to efl ect a sluicing action. This expedient is effective on the upper portion of the ladder but is absolutely ineffective forthe lower or immersed portion of the ladder inasmuch'as the water used for sluicing together with the material carried away by. it is dissipated immediately upon merging with the water upon which the dredge is floating.

It'is therefore an object of my invention to provide a means for preventing undue accumulation of materialflon a dredge ladder.

due to the fact that ,the material being.

Another object of my invention fis to provide a construction for a dredge ladder which is comparatively light in weight.

, The foregoing and I other objects are attained in the embodiment of the invention as shown in the drawings, in which Figure 1 is a simplified showing of the forward portion of a dredge embodying a ladder constructed in accordance with my invention.

Figure 2 is a side elevation to an enlarged scale of the upper portion of a ladder in ac cordance with my invention.

Figure 3 is a side elevation tothe same scale as Figure 2 of the lower portion of a 'dredgeladder' in accordance with my inven dredge'ladder of my invention.

' Figure 9 is a diagrammatic plan of the con-' trolling lines for a dredge ladder..

Figure 10 is similar to Figure 9 but discloses a modified form of control lines fora dredge ladder.

In its preferred form, the dredge of my invention includes a ladder comprising a pair of side plates joined intermediate their ends by a plurality of diaphragms which present a minimum obstruction to material discharging from the bucket lines encompassing the ladder and the ladder is further provided with a deflector adjacent the lower or immersed end thereof for directing the flow of discharged material.

In the form of my invention shown herein there is provided a dredge, generally designated 6. At its forward endof the dredge is provided with a boom or gantry 7 which is re tained in place by suitable tackle 8 anchored to the dredge frame 9. Suspended from the outer end of the gantry 7 is additional tackle 11 adapted normally to extend below the surface of the water, indicated at 12, to support the lower, immersed .end of a ladder 13. The upper end of the ladder is carried 011 a shaft 1d mounted in the dredge frame 9. By suitably operating the tackle 11 the lower end of the ladder 13 can be raised and lowered into and out of the water to control the point at which the dredging operation occurs. The

ladder usually is operated about in the posi tion shown in Figure 1 at a considerable inclination to the horizonta Lateral movement of the ladder and of the forward end of the dredge is controlled by'lines running over sheaves and located by stationary piles 15 according to either of the schemes shown in Fi ures 9 and 10.

t the lower end of the ladder 13 is disposed a tumbler 16 about which passes a conveyor 17 including a line of buckets 18. The upper run 19 of the line of buckets follows closely the upper edge of the ladder 13 and passes about an upper tumbler 20 on the shaft 1 1. Thelower or return run 21 of the conveyor follows for a distance the lower edge of the ladder 13 and then depends there-from in a curve to return to the lower tumbler 16 and repeats the circuit. The conveyor or line of buckets thus encompasses the ladder 13. V In constructing the ladder 13 I preferably provide a pair of side plates 22 and 23 which are substantially co-extensive and are disposed in parallel relationship. The plates eX- tend substantially from the upper tumbler 20 to the lower tumbler 16 to provide a pair of parallel beams. In practice the side plates are preferably fabricated of a plurality of smaller platesections but in effect they are continuous and I therefore refer to them in the claims as side plates. These plates 22 and 23 are preferably reinforced along their edges with suitable angles such as 24 and are in general provided with the usual structural features The upper edges of the side plates 22 and 23 are customarily provided with a series of spaced rollers 26 adapted to support the upper run 19 of the line of buckets.

The upper portion of the ladder 13 as particularly shown in Figure 2, is provided between the side plates 22 and 23 with a top plate 27 disposed slightly below the upper bounding edge of the side plates and eXtend ing parallel to the upper surface thereof. Material which is discharged from the buckets 17 adjacent the upper portion of the ladder 13 is deposited on the top plate 27 and is sluiced therefrom by a stream of water playing upon the upper end of the top plate. The top plate prefeably extends along the 1 adder 13 to a point adjacent the water line or the point of immersion of the ladder. The

sluicing action is therefore effective on the upper portion of the ladder to remove any deposited material and dissipate it into the body of water.

In order, however, to maintain the ladder 13 free from deposited material below the water line where its weight is particularly objectionable and where unsuccessful attempts have been made in the past to prevent the deposit of extraneous material, I preferably interrupt the top plate 27 and interposc between the side plates 22 and 23 a plurality of dialilhragms 31 which preferably are metal plates spanning the side plates 22 and 23 and secured thereto by any suitable means and additionally held by angles 32. The diaphragms 31 are preferably located in the ladder 13 at a considerable inclination with respect to the upper bounding edge of the side plates 22 and23 so that the diapnragms e2;- tend substantially vertically when the ladder 13 isin a digging position as is disclosed in Figure 1. The diaphragms 31 thus present a minimum obstruction to the discharge of material falling from the line of buckets 17 and permit the material to fall gravitational.- ly through the water and pass the lower line of buckets 17 to deposit on thebottom of the body of water. relatively quite thin they present 0111 a very small area upon which material can lodge and therefore insure that the weight of the ladder will be increased only an insignificant percentage by the interception of such discharging material.

Although the diaphragms 31 are quite effective for their purpose it is in practice difficult to continue their use to the extreme lowor end of the ladder 13 because of the strong bracing necessary for the lower tumbler 16 and the additional reinforcement required by the ladder at this point. I therefore construct the ladder particularly as shown in Figures 3 and 4c. The diaphragms 31 are not used in close proximity to the lower end but I preferably span the side plates 22 and 23 with a deflector 33 which is preferably a metal sheet of inverted V cross section located adjacent the upper bounding edges of the side plates 22 and 23 and extending from the lowermost diaphragm 31 approximately to the tumbler 16. The angle of the deflector 33 is such that the path of material falling into the buckets passes over the deflector without lodging thereon. That is, the effective angle of the deflector is the angle that the path of a piece of material falling over the deflector makes with the horizontal. It is the resultant of the angle of the ladder 13 with respect to the horizontal and the angle of inclination of the deflector 33 with the ladder 13. The angle referred to is preferably greater than the angle of repose of any material discharged by the bucket which, therefore, is directed away from the ladder 13 to fall to the bottom of the body of water.

In accordance with my invention there is provided a means for preventing undue accumulation of deposited material on the lad- Since the diaehra ms 31 are der of the dredge thereby enabling the designer to construct the ladder without regard to excessive overloads by virtue of deposited material and to provide a structural arrangement which is not only amply strong but is extraordinarily light for this class of service. Furthermore, there is provided not only a way of offering practically no obstruction to material adjacent the central portion of the ladder but there is also afforded a way of dissipating material which ordinarily would deposit adjacent the lower end of the ladder and near the lower tumbler.

I claim:

1. A dredge comprising a ladder, side plates on said ladder, and diaphragms spanning said plates and inclined to the longitudinal axis of said ladder.

2. A dredge comprising a ladder, side plates on said ladder, diaphragms spanning.

said plates and inclined to the longitudinal axis of said ladder, and a deflector spanning said plates between their upper edgesand adjacent to said diaphragms.

3. A dredge comprising a ladder having a longitudinal axis, parallel side plates on said ladder, a deflector spanning said plates adjacent one end of said ladder, and diaphragms inclined to said axis and spanning said plates between the ends of said ladder.

4. A dredge comprising a ladder adapted to be disposed normally at an inclination to the horizontal, parallel side plates on said ladder, and diaphragms spanning said side plates and adapted to be disposed normally substantially vertically.

5. A dredge comprising a ladder including a pair of coextensive, parallel side plates, an inverted V-shaped deflector fastened to the upper edges of said plates adjacent one end thereof, and a plurality of diaphragms fastened to and extending between said plates, said diaphragms being materially inclined to the bounding edges of said plates.

6. A dredge comprising a ladder havin a longitudinal axis, side plates on said ladder, and diaphragms spanning said plates, said diaphragms being inclined to said axis and defining substantially uniform passages vertically through said ladder.

In testimony whereof, I have hereunto set my hand.

- WALTER B. MAOAULAY.

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