US2029815A

US2029815A - Dredging apparatus

Info

Publication number: US2029815A
Application number: US740475A
Authority: US
Inventors: Ewing Williard Rea
Original assignee: MCWILLIAMS DREDGING Co
Current assignee: MCWILLIAMS DREDGING Co
Priority date: 1934-08-18
Filing date: 1934-08-18
Publication date: 1936-02-04
Anticipated expiration: 1953-02-04

Description

W. R EWING DREDGING APPARATUS Filed Aug.' 18, 1934 3 Sheets-Sheet 1 DREDGING APPARATUS Filed Aug. 18, 1954 5 sheets-sheet 2 Eb. 4, i936.

W. R. EWING DREDGING APPARATUS Filed Aug. 18, 1934 5 Sheets-Sheet 5 Patented Feb. 4, 1936 UNITED srATss DREDGING APPARATUS Application August 18,

8 Claims.

This invention relates to hydraulic dredging apparatus and mo-re particularly to means for anchoring the same.

In accordance with known practices, on floating hydraulic dredges, two anchors are customarily employed, the anchors being spaced laterally from the dredge boat at points approximately opposite the front end, during operation. Prior to the use of the present invention, these anchors were lifted and moved, from time to time, as the dredging process required, by means of barges or boats separate from the main dredge boat. These barges were provided with hoisting apparatus to raise and lower the anchors but in- 1 asmuch as the anchors for large dredges were often quite heavy, several men were required to hoist an anchor, move it to a new position and drop it. This manner of moving the anchor required considerable time, during which dredging operations had to cease and the anchors were often not dropped the same distance in advance of the dredge boat so that care had to be exercised in order to avoid uneven dredging or cutting. Also, where the dredging operation was in a swamp, navigation of the auxiliary anchor barges was difficult or impossible.

It is an object of the present invention to provide means to remedy these conditions by providing an arrangement for anchoring a dredge boat which is capable of operation in all kinds of places.

It is a further object to provide anchor moving and locating means which are capable of speedily and accurately moving anchoring devices and without the use of auxiliary barges or the like.

Other objects and advantages reside in certain novel features of the arrangement and construction as will be apparent from the following description, taken in connection with the accompanying drawings, in which:

Figure l is a fragmentary plan view of a dredge boat showing portions of the invention attached thereto;

Figure 2 is a view in side elevation of a portion of the apparatus of Figure 1 and showing one of the anchors in position;

Figure 3 is a diagrammatic showing, in plan View, illustrating the operation of the invention;

Figure 4 is a fragmentary plan view illustrating the construction of a detail of the supporting structure; and Figure 5 is a fragmentary plan view of the front end of a dredge boat constructed in accordance with the invention and showing means which can be operated from the main dredge boat 1934, Serial No.A 740,475

adapted to support parts of the A frame, the ladder and an anchor boom thereof.

Referring to the drawings in detail and particularly to Figures l and 2 it will be seen that a portion of a hull of a dredge boat is indicated by the reference character H. A suitable enclosure l2 may be provided for housing the engine, pump, hoisting drums etc. in accordance with known practices.

Near the front end of the dredge boat, a supporting structure or gallows` frame i3 is provided, which, by means of cables or chains supports the upper end of an A-frame lli and through it, the front end of the ladder l5, to which the cutter l5 and suction line il of the hydraulic dredge are attached. The ladder l5, together with the cutter I6 and suction line Il are supported on the A-frame l by means of cable i3 (connected to a suitable drum on the deck, not shown) and the pulley blocks iii and chains "55. The A-frame M and the ladder l5 are pivotaHy mounted on the front end of the dredge boat at two points spaced slightly inwardly from the sides of the hull. As indicated in Figure 5, a single casting I3 may be employed for this purpose. In the arrangement shown, the A-frame It is pivoted to the members I8 slightly above the top of the deck while the ladder i5 is pivoted to these members at the front of the hull H and some distance below the deck.

r.T wo cables i9 (see Fig. 2) of xed length normally support the A-frame lli on the gallows frame I3. In accordance with the present invention the stress on these cables may be wholly or partially relieved by the auxiliary supporting structure indicated by the

reference characters

2t, 2i, 22, 23, although the primary purpose in this auxiliary assembly is to provide means for supporting the two anchor booms shown at 24. I'lhe anchor booms constitute important parts of the invention and will be explained hereinafter.

In order to support the anchor booms so as to cause them to operate properly, it is necessary to provide fixed pivot points for them. For this purpose boom feet 25 (see Fig. 5) are secured to the hull just outside the location of the pivotal supports i3 for the A-frame and ladder. This readily solves the problem of supporting the lower ends of the anchor booms. To support the upper ends of the anchor booms is not so simple, It would naturally be supposed that cables could easily be rigged from the anchor booms to suitable points on the supporting cables I9 but it has been found by experience that this arrangement is not at al1 satisfactory. The A-frame must be held in fixed position by the cables I9 and this cannot be accomplished if booms are hung on them.

In accordance with the present invention, a floating spar or strut member 22 is supported from the gallows frame I3 and A-frame I4 by a set of

cables

29 and 23, together with the bracing cables 2|. The location of the strut 22 is irnportant. As shown in Figure 1, it is slightly in front of the front edge of the boat so that the ends of the strut occupy positions slightly in front of, and slightly outside of the feet 25 for the anchor booms.

The upper ends of the anchor booms 24 are suspended from the outer ends of the strut 22 by means of cables 26. Auxiliary cables 21 may also extend from the ends of the strut 22 to some intermediate points of the anchor booms 24.

By employing the strut 22 and the cables 20, 2| and 23 arranged as shown, there is Very little tendency to raise the A-frame due to the weight of the booms 24.

' This will be apparent when it is noted that because of the length of the strut 22, the outer ends of the strut, at the points where the

cables

20 and 23 are attached thereto, are outside of the shortest line from the gallows frame I3 to the A-frame I4. Thus, with the anchor booms 25 f not attached to the strut 22, this member is under compression due to the weight of the A-frame. When the anchor booms 24 are suspended on the ends of the strut 22, the resultant forces on the strut 22 may change from compression to tension, but the strut and the A-frame will not move. The horizontal component of the force resulting from the weight of the booms will be taken up by the strut 22 and by the cables 29 so long as the booms are in advance of the front Y end of the dredge boat. There will be very little if any vertical stress thrown upon the

cables

29 and 23 by the booms. In fact, it is possible to make the cables 26 and 2'! of such a length that the ends of the booms are at the same height as the strut 22 in which case there would be no vertical component of force on the

cables

20 and 23. Under these circumstances, the booms could not be used to best advantage, however, because their ends would not be spaced as far from the dredge boat as in the arrangement indicated. Two anchors (one of which is shown at 28 in Figure 2) are employed to hold the front end of the dredge boat in position. During digging operations, these anchors are set at points spaced laterally from the front end of the boat, and are connected to the boat through cables 29 which run over sheaves 39 on the ladder I5, sheaves 3l on the A-frame and from there to suitable drums 32 on the main deck which may be operated by an electric motor 33 or the like. By hauling in one cable 29 and letting out the other, the dredge boat may be swung about either of the rear spuds 34 (see Fig. 3).

In order to move the anchors 23 from one location to another, cables 35 are connected thereto and pass upwardly through sheaves 36 on the anchor booms 24, thence to sheaves 31 on the upper part of the A-frame I4, downwardly along the A-frame I4 to sheaves 38, located as low on the A-frame as is convenient and from there to drums 39 on the deck. The drums 39 may be actuated by suitable gearing and clutches from a shaft 40 driven by an electric motor III.

Because of the fact that the sheave 38 is located rather low on the A-frame I4, the tendency to raise the A-frame by pulling on the cables 35 is slight, even though the load on these cables is high and the booms 24 are swung out laterally to considerable extent.

In the showing of Figures 1 and 2, the booms 29 are shown broken away. They may be of considerable length and during normal operating conditions would extend out laterally at nearly right angles to the longitudinal center line of the boat (see Fig. 3). Cables 42 of fixed length are used to limit forward movement of the booms 2. In Figures 1 and 2 these are also shown as broken away.

The operation of the anchoring and anchor moving means is as follows:

Assuming that the anchors 23 are in position at points beneath the ends of the booms 24, digging operations may be carried on, the entire dredge boat being swung about one or the other of the spuds 3G by pulling on one or the other of the cables 29 to move the cutter and suction line back and forth across the channel. As the dredging proceeds the boat is moved forward, gradually to the dotted line position indicated, although the anchors remain in the same position.

In moving the boat forward, one Spud, and then the other, is raised as the dredge is swung back and forth by the cables 29 so that the dredge is walked forward. Thus in Figure 3, the spud 34 shown at the top of the figure may be raised. The boat then pivots about the Spud shown on the lower side of the figure, and as the boat is swung toward the right (as viewed from the left of the drawing) the left spud is advanced. If the left Spud is now set, the right one raised, and the dredge swung to the left, the boat is advanced correspondingly. This provides means for Inoving the dredge forward accurately as the digging proceeds. To secure best operation, it is important to also move the anchors forward accurate distances, although the anchors n eed not be moved every time the boat swings back and forth.

If now it is desired to move the anchor 28 shown in Figure 3 forward, the dredge is swung t-o the right, (as viewed from the left of the gure) so that the boom 24 shown is approximately over the anchor. The cable 42 will then be loose because of the position of the boom. By operating the right hand drum 39, the right hand cable 35 will be tightened and the anchor` lifted. Due to the fact that the end of the strut 22 is in advance of and outside of the boom foot 25, the boom 24 will tend to swing forward by gravity. It is not necessary to exert much force on the cable 35, therefore7 to swing the anchor forward. The forward movement of the boom 24 being limited by the cable 42, the anchor may be accurately positioned before being dropped.

After the anchor 28 has been positioned, the boat may be swung to the left and the anchor not shown in Figure 3 may be advanced in the same way.

It is desirable to maintain a slight tension on the cables 35 at all times in order that the booms may be held in operative position and in Order that the operator may be appraised of the posi.. tion of the anchors by noting the position 0f the booms. The clutches used for operating the drums 39 may be so constructed as to drag a little at all times so as to maintain the requisite tension on the cables 35.

While only one embodiment of the invention has been shown and described herein, it is obvious that many changes may be made without departing from the spirit of the invention or the scope of the annexed claims.

I claim:

1. In combination, a hydraulic dredge boat having a -gallows frame, an A-frame and a ladder mounted on the front end of a hull, two anchors for holding the front end of the hull in position for dredging, cables connected to said anchors and passing over sheaves on said ladder, operating drums mounted on the hull and connected to said cables for swinging the front end of said boat back and forth between said anchors, two anchor booms having their lower ends pivotally mounted on said hull, means for supporting the upper ends of said booms, comprising a strut member, cables for supporting said strut member laterally of the boat between the said gallows frame and said A-irame at a point slightly in advance of the lower ends of said booms, cables extending from said strut member to the upper ends of said booms and power actuated cable means connecting said anchors to said booms for supporting the anchors on said booms and for moving said booms.

2. In combination, a dredge boat having a gallows frame and an A-frame, two anchors for holding the boat in position for dredging and an arrangement mounted on the boat for moving said anchors, said arrangement comprising two anchor booms pivotally mounted on said boat, a strut member, means for supporting said strut member from said gallows frame and said A-frame, means for supporting said booms from said strut member and power actuated means for supporting said anchors on said booms and for swinging said booms.

3. In combination a dredge boat having a gallows frame and an A-frame on the front end thereof and two spuds on the rear end thereof, two anchors for holding the front end of the boat in position for dredging, cables connected to said anchors for swinging the dredge boat about one or the other of said spuds, and an arrangement mounted on said boat for moving said anchors, said arrangement consisting of two anchor booms having their lower ends pivotally mounted on the front end of said boat near the sides thereof, means for supporting the upper ends of said booms at points between said gallows frame and said A-frame and power actuated means for supporting the anchors on said booms and for moving said booms.

4. In combination, a dredge boat having a gallows frame and an A-frame on the front end thereof and two spuds on the rear end thereof, two anchors for holding the front end of the boat in position for dredging, cables connected to said anchors for swinging the dredge boat about one or the other of said spuds, and an arrangement mounted on said boat for moving said anchors, said arrangement consisting of two anchor booms having their lower ends pivotally mounted on the front end of said boat near the sides thereof, a strut member, means for supporting said strut member from said gallows frame and said A-frame in such position that it extends transversely of the boat with its ends above, slightly in advance, and slightly outside of the lower ends of said booms, means for supporting the upper ends of said booms from the said strut member and power actuated means for supporting said anchors on said booms and for swinging said booms.

5, In combination, a dredge boat having a gallows frame and an A-frame lon the front end thereof and two spuds on the rear end thereof, two anchors for holding the front end of the boat in position for dredging, cables connected to said anchors for swinging the dredge boat about one or the other of said spuds, and an arrangement mounted on said boat for moving said anchors, said arrangement consisting of two anchor booms having their lower ends pivotally mounted on the front end of said boat near the sides thereof, a strut member, means for supporting said strut member from said gallows frame and said A-frame in such position that it extends transversely of the boat with its ends above, slightly in advance, and slightly outside of the lower ends of said booms, means for supporting the upper ends of said booms from the said strut member and power actuated means for supporting said anchors on said booms and for swinging said booms, said last mentioned means including cables extending from drums on said boat to points on said A-frame, from there to the ends of said booms and from there to said anchors, the arrangement being such that the anchors are swung by gravity when supported on said booms.

6. In a dredge boat having a gallows frame and an A frame on the front end thereof, an anchor for holding said boat in position for dredging and an arrangement for moving said anchor, said arrangement including a boom having its lower end pivoted to the deck of said boat, means for supporting the upper end of said boom to enable said upper end to swing about an upper pivot point in advance of said gallows frame and in the rear of the upper end of said A-frame and means for supporting said anchor on said boom.

7. In a dredge boat having a gallows frame and an A frame on the front end thereof, an anchor for holding said boat in position for dredging and an arrangement for moving said anchor, said arrangement including a boom having its lower end pivoted to the deck of said boat, means for supporting the upper end of said boom to enable said upper end to swing about an upper pivot point in advance of said gallo-ws frame and in the rear of the upper end of said A-frame, means for supporting said anchor on said boo-m and means for limiting forward movement of said boom.

8. In a dredge boat having a gallows frame and an A frame on the front end thereof, an anchor for holding said boat in position for dredging and an arrangement for moving said anchor, said arrangement including a boom having its lower end pivoted to the deck of said boat, means for supporting the upper end of said boom to enable said upper end to swing about an upper pivot point in advance of said gallows frame and in the rear of the upper end of said A-frame, means for supporting said anchor on said boom and means for limiting forward movement of said boom, the arrangement being such that when the anchor is supported on said boom, the boom tends to swing forwardly by gravity action.

WILLIARD REA EWING.