US2181526A - Pile shield - Google Patents

Description

J. UPTON PILE SHIELD Nov. 28, 1939.

Filed Aug. e, 1937 4 sheets-sheet 1 /1 n (//ron ATTORNEY INVENTOR i BY .C.

NOV. 2& 1939. H L UPTON v 2,181,526

PILE SHIELD Filed Aug. 6, 1937 4 Sheets-Sheet 2 ATTORNEY Nov. 281 1939.

J. UPTQN PILE SHIELD Filed Aug. 6, 1957 4 Sheets-Sheet 5 |NVENTOR BY 75k/7 (//zon ATTO NEY Patented Nov. 2s, 1939 UNITED STATES PILE SHIELD John Upton, Wayland, Mass.,

assignor, by direct and mesne assignments, to Anderson Products, Inc., Cambridge, Mass., a corporation of Massa-y chusetts vApplication August 6, 1937, Serial No..157,709

lis claims. (C1. 61-54) This invention pertains to a means and method ofv protecting wooden piles such as are used in various forms ofv marine construction work.`

.The wooden lpiles that are in general. use in harbors, both in this country and abroad, are subject to severe damage by certain marine amphipod Crustacea, particularly the teredo navalis, Limnoria and Chelura. These forms of marine life are found in large numbers in practically all harbors in the tropic and temperate zones.

Many ways have been tried to eliminate the destructive results occasioned by these animals. The piles have been treated by creosoting before beingplaced in the Water. This has proved of "mate-rial assistance, as the worms do not find such conditions favorable. However, the great mass of the piles now in use in harbors are un.- treated and are being rapidly eaten away. The problem, therefore, that confronts those in charge of maintaining marine structures, such as docks, wharves, piers, and the like, is how to prevent or arrest further destruction of the piling.

y The prior art shows that many means in the form of shields placed about the piles in one form or another have been attempted. The problem is one of long standing and involves structures of large cost and hence it is significant that up to the present time no satisfactory shield to prevent this damage has been devised.

Of those that have been used there is no record thatrthey have accomplished the result'intended and it is common knowledge among authorities on this subject that there is no means available on the market today which can satisfactorily cure this condition.

It is well knownthat when a pileis surrounded by sand or other divided inert material which Willpack closely about a pile, circulation of water thereabout is checked and destructive animal life present in the pile is promptly eliminated, as the animals die upon the exclusion of oxygen which would normally be brought to them by water circulating about the pile. Thus, we iind that the portion of a pile which is embedded in f the bottom is not attacked and likewise, if that portion of a pile extending from the bottom to the high water mark is surrounded by a column of sand which may be retained in position by a tubular member, the latter portion will also be preserved from attack by these marine Worms, or, if the worms have been present in the pile they will die shortly after column of sand or similar material. v

This feature has long been known and many attempts have been made to provide a tubular the application of the shield about the pile extending from the bottom to above high water in which sand might be positioned. The theory is simple. The difficulty has resided in making a shield from which the sand will not escape. On itsface this should not seem diicult but the situation in practice is this. In harbors the mudline, that is, the surface of the bottom, constantly shifts from one cause or another. As harbors are deepened, the mud about the pile tends to slide gradually downwardly toward the deeper portions of the harbor and in this way portions of the pile which had previously been embedded in the bottom will become uncovered. Thus, any shieldwhether of metal or concrete, which is aixed to a pile so that it may not move longitudinally becomes of little use when the mudline has dropped below the bottom of the shield for upon arrival of this conditio-n the worms promptly find the unprotected; wood and recommence their destructive efforts.

The descending mudline condition yhas also been appreciatedin the` prior `art as there have been devised pile shields which merely rest on the bottom andv as the bottom is washed away the shield descends therewith and theoreticallyr the shield continuously holds the sand or other material within the shield about the pile. However, in practice this type of shield has not functioned as might normally have been expected for the fact that the'bottom inevitably'washes away at some portion about the circumference of the y shield. sufiicient to lprovide a smallopening between the harbor bottom and thebottom of the shield and immediately, .upon the development of this situation, the sandA contained within the shield promptly ilows downwardly and out through the opening. That this can happenso readily is because sand, in water, is very fluid. To overcomey thisjdifiiculty the prior art shows the introduction of bottom closure devices, usually in the form of inwardly extending radial sections kor gaskets which fit more or less closely about the pile and are relied on to retain the sand with inthe shield. These, however, likewise have not proved successful in preventing the escape oi' sand once the harbor bottom has washed away below the bottom of the shield at so-me point. The reasons whyA this last mentioned type of shield has notv functioned are somewhat com- 5 pleX, and need not be described yin detail. It is believed sufficient -to say that they will not work and no device ofthe prior art will be found in practical use, although the demand for such a unit is wide spread. l

any shifting that may take place in the niudline of the bottom in which the pile is driven. My invention may be used in connection withnew piles to prevent subsequent destruction by the aforementioned Crustacea or it may be applied to a pile already attacked with a result that such animal life will be killed and destruction arrested.

Other objects of my invention will become apparent as the description proceeds Awith the aid of the accompanying drawings, in which:

Fig. 1 shows two piles partially destroyed,

around one of which my pile shield has been applied but not filled with sand or other protective material;

Fig. 2 is a perspective view of one of the upper sections of my pile shield;

Fig. 3 is a section on the line 3 3 of Fig. 2 illustrating the internal spacers used to prevent the pile from touching the shield;

Fig. 4 is a sectional detail showing the means for maintaining the sections in telescoping relation;

Fig. 5 is a plan view of the bottom section of my unit prior to application on a pile, showing a preferred form of sand check;

Fig. 6 is a section on the line 6 6 of Fig. 5;

Fig. '7 is a sectional view showing the device shown in Fig. 5 as applied to a pile including a skirt member attached to the bottom of the shield;

Fig. 8 shows one-half of a skirt adapted to be attached to the bottom of a shield, having its lower edge at an angle to conform with the slope of the bottom;

Fig. 9 is a section on the line 9-9 of Fig. 5 showing spring means for exercising downward pressure on the sand checks;

Fig. l is a section on the line lU--IU of Fig. 5 showing the hinge mechanism;

Fig. 11 is a section on the line H-II of Fig. 5 showing the nature of the overlapping segmental sand checks; v

Fig. 12 is a View similar to Fig. 5 showing the bottom section with a modified form of sand check positioned about a` pile;

Fig. 12a is a sectional perspective of the form of sand check shown in Fig. 12;

Fig. 13 illustrates the condition that prevails when my unit is in position about a pile and lled with sand or similar material;

Fig. 14 illustrates the manner in which my unit settles about the pile as the bottom is washed away while at the same time preventing the escape of the material within the unit;

Fig. 15 is a View similar to Fig. 13 with the exception that the shield has a sloping vbottom skirt adapted to conform to the slope of the bottom;

Fig. 16 is a view similar to Fig. 14 showing the situation after the sloping bottom of Fig. 15 has been washed away;

Fig. 1'7 shows a further modification of the sand checks in which the segmental sections are integral with the side wall;

Fig. 18 is a section on the line lf3- I8v of Fig.

17, the dotted line illustrating the position the sand check assumes when in position about a pile;

l Fig. 19 is an elevation partly in section showing a replacement unit adapted for easy insertion in the uppermost undamaged original section;

Fig. 20 is a sectional view showing a modiiied form of hook and spacer used in supporting one section on another;

Fig. 21 is a vertical section on the line 2|-2I of Fig. 20 showing the manner in which the spacers hold the shield away from the side of the pile.

Referring now to Fig. 1 it will be seen that the pile 2 is surrounded by a tube or shell composed of a plurality of sections il and 6 and a bottom section 8. The upper sections 4 and 6 may be of any convenient length and number provided, however, that the upper end of the topmost section is above the range of attack of the worms.

The bottom section 8 is of special construction differing from sections 4 and E and will vbe described hereinafter. The tubular sections 4 and 6 may be made in any convenient manner in eitherY one or more pieces, provided they may be positioned readily about the pile.

Fig. 2 shows one suitable form of section I have employed. In this case the section is a continuous sheet of relatively thin metal having suitable resistance to corrosion from the water. A plurality of lugs li) and l2 are secured adjacent the long edges of the tube to cooperate with bolts I4 for securing the unit about the pile after it has been slipped thereover or thereabout. At`

the bottom of each section are a plurality of combination hooks and spacers I6 one of which is shown in detail in Fig. 4. These hooks are so arranged that the section above may be lowered telescopically within the section below so that the hook portions it! extend outside of the lower section thus to support the upper section thereabove. The portion of member I6 within the section, as at 2U, is utilized as a spacing member to prevent the pile from coming in contact with the shell or tube, should `the former not be centered with respect thereto. The distance between spacers 20 is governed by the diameter of the pile with which the shell is used.

The lowest regular section of the tube, in this case section 6,- rests on a special bottom section which is shown in Figs. 5, 6 and 7. This bottom section 8 is, in my preferred form, made in two halves, 22 and 24, having flanges 26 and 28 adapted to be bolted together to form a tubular member. The tube so formed is of the proper diameter to allow the section immediately above to be telescopically installed and positioned by means of hooks I 8.

Intermediate of the ends of the bottom section d are a plurality of segmental sections which I have termed sand checks. In Fig. I have shown six sand checks, 32, 34, 35, 3856 and 42, the edges of which overlap and of which every other one, as 32, 34 and 36, overlies adjacent segments 38, 11E! and 42. Considering sand check 36 illustrative of the overlying sand checks it will be seen that it is hinged at 43 to a supporting portion im which is secured to the wall of the bottom section. The hinge construction is shown in Fig. while Fig. 9 illustrates a coil spring i5 that I use to urge the sand checks downwardly. One end of the spring rests on the shield wall, the other on the overlying sand check. Movement, however, below the horizontal is prohibitedby the flange 46 ofthe sandcheckI pile.

which engages the bottom of the horizontal portion of support 44.

The underlying sand hinged to supports 44 -at y43, have their radial edges bent downwardly. as at 48, shown in Fig; 11.' This isto prevent binding when the sand checks v are swung upwardly in `assuming their position about a pile.k

It will be observed in Figs. 1, 6, 7, y 13, 14, 15 and 16 that there is a substantial distance between the sand checksy and the lower edge of the bottom section to .which the sand checks are attached. That portion of the yshell which Figs. l2 and 12a show a modied form of sand check. In this case the segmental sections while similar in form to those shown in Fig. 5 are not hinged to, but rather are integral with, the supports 44 that are secured to the semi-cylindrical sections 22l and 24. When sand checks of this type are positioned about a pile they bend upwardly along the lines 54. Since the metal of whichthese checks may be made is relatively thin gauge, it may be necessary to provide additional spring means of some sort Kto more firmly urge the segments against the pile that centering of the pile may be definitely accomplished. Such spring means is shown fat 5S in the form of a coiled spring having vone end resting against the Wall of the tube and the other end pressing downwardly on the lsand check.l Fig. 12 is also illustrative of the situation that developes when oneof the sand checks comes to rest on some projection 55 that may extend from the pile, as for example, a Iportion not eaten away by the worms' or a stub of a branch not cut off closely when the tree was felled. When an underlying segment happens to come to rest against a projection as shown it will of necessity raise the adjacent overlying sections a slight amount so that there may be clearance between the sand checks andthe pile.

lThis, of course, is an undesirable condition, but, by virtue of the loperation of my -skirt`50 extending below the sand checks, escape ofl sand' is prevented.

Fig. 17 illustrates a still further modification of the manner of construction of the sand checks. In this case, segments 58 are integral with the side wall 22, bending upwardly7 as at B0 in Fig. 18 when applied about a pile. Additional spring means, such as shown in Fig. 12a, may Abe used to urge the segments against the pile with greater force, if necessary, to maintain the lower end of the `shield centered with respect to the Having thus described the general construction of my unit I shall now explain the method of application and operation in the prevention of the escape of sand or other materialr therefrom.

The two halvesof the bottom section 8, each of which already has the sand checks properly positioned and fastened therein, and an-.appropriate skirt extending therebelow, are secured about the pile.

4checks 38.40 and 42,

In order to determine the properV type ofskirt to be used in connection with. the bottom section, consideration is given to the nature of the bottom in which the pile is em-y bedded. If the bottom is substantially level,

a skirt of uniform width with such as 50 shown 5 -in Figs. 1, 7 and 17 is secured to the lower edge ofthe bottom section to provide a length of not less than 8 inches, in the ordinary case,

from the sand check to the bottom of the skirt. If, however, the diameter of the tube is'increased for use with piles` of larger diameter, the distance from the bottom of the sand check to the bottom lof the skirt should be correspondingly increased and conversely, if smaller tubes v are used, ythe skirt length 'may be reduced. The reason'for this will presently appear. If, on the other hand, vthe bottom in which the pile is it shall penetrate the bottom a substantially -uniform distance about its entire circumference. Of course, however, the bottom skirt and the bottom section may be made integral as at 49 in Figs. 12a, 13, 14, 15 and 16, but I have found it more convenient to follow. the aforementioned procedure.

After a skirt has been selected to match the 'embedded is sloping, as shown for example in i Slope of the harbor bottom, the bottom section with skirt attached forced downwardly along the pile and the rst-main section 6 is positioned thereupon with its Vlower end inside of bottom section 8. The hooks I8 ofcourse support section 6 in position. The shield thus `far assembled is then forced downwardly further and another section, as for example 4, is positioned on top of the preceding section in the same manner. This procedure continues until the tube thus assembled strikes bottom andthe upper end is above the portion attackedby the Crustacea. Usually by this time, the weight vof,

the tube itself rwill cause the lower edge vof the l skirt to cut into the bottom a distance determined bythe nature of the bottom material. Suchva condition is shown in Fig. 1. If, by any chance, the pile about which the shield is positioned is crooked, the shield will be able to conform to the pile because the telescoping jointsv are not rigidly connectedv and the tube may bend at these overlapping areas. This is a point of considerable importance as the number of warped and distorted piles is larger than might be supposed.

With the shield in itsfmal vertical position about thepile and with the lower end embedded a suitable distance in the bottom, I have provided means .in the form of my sandv checksfor accurately, centering the lowery end of the shield with respect to the pile. This is, accomplished by makingthe sand checks of suitable sizewith pile varies but, howeyerthatmay be, the overlapping;` segments .forming the sand checks,` prof vide an inverted bottom section iii-,ting rela-V tively closely about. the pile and having, such iiexibility` thatV the bottom section witl'r` the sand` i checks.attachedisfreeto slide stillfurther downwardly along.. the. pile as the bottom materialmaybe washed away.

The'sand checks when set. at an angle in the neighborhood of` degrees and urged down- 19 wardly lay-springs 45 or liti provide an efficient and positive means for maintaining, the pile centered.l with, respect, to the bottom section 8. Any lateral force that mightbe exerted against the bottom of thev pile in any direction by move- 155 ment ofthe current or bottom or otherwise will in Figs. 1, 2J 3. and'fi.

253 tact with the wall of the tube atv any point.

This is very. important because I have found that ifthe. pile, due to a warped or crooked condition, should touchthe wall at any point a void will invariably be formed immediately. below the point" of contact when the tube is subsequently filled-withisand. The` formation ofsuch a void would 'permit the Crustacea to continue their destruction at this point and, furthermore, should the void by chance be adjacent a joint of the tube it is possible that Crustacea might work .their way through the joint to renew the damage toV the pile.

The inward extent and circumferential spacing of the spacersl 2G is determined by the diameter of the pile coupled with the extenty the pile deviatesfrom its normal vertical axis. Ii the pile happened to be very crooked it would be necessary to have the spacers 2li extend inwardly aV greater distance in order to be sure that the f. pile could not touch the wall.`

With the unit in position as in Fig. i, and, of course, filled with water, sand or other yrelatively finely divided inert material is introduced in anyconvenient manner at the top of the tube andas the tube-is gradually filled the water therein is displaced. The sandbegins to pile up on the Sand'checks and as this proceeds the sand checks are urged downwardly to exert greater pressure atitheir ends against the pile, minimizing whatever clearance may have been present: initially. At the same time the weight of the sand; as it collects on the bottom formed by the sand checks, is transferred to the bottom section 6 through the supports Il@ attached thereto with a result 'i that the bottom edge of the skirt is driven deeper and'deeper into the mud. A conditionof equilibrium is reached when either the bottom edge ofthe skirt has gone so deeply into the mud that the mud within the skirt has risen high enough to engage the underside of the' sand checks or a suiicient amount' of sand has filtered between the sand checks to fill the small remaining space between the top of the mud within the skirt andthe bottomvof the sand checks.

isv well embedded in the mud and there is no possibility of the shield rising as it, through the sand checks, carries the heavy load of the column of sand which lls the shield. A similar ."situation is developed when the diagonally cut.

In either` event, the bottom edge of the shield skirt used and; in such;v case a; condition; of

equilibrium is reached after the lowerl edge; ofv

Where:- the;` bottom is quite hard the depth to whichvtheslfrieldfwill sink.; in the; bottom is still less-;but,.,in1v any event, it;will always penetrate the bottom. suii'icientlyA tof, adequately seal' the sandwithinfthe tube.

It shouldbepointed out; however, that, when the tube is` first positionedfabout the pile and prior to being lled with sand the weight of the tube itself is not sufficiently great-to drive it into even a soft bottom more than theidepth of the skirt thatiextends below the sand checks. This is essential in order that the bottom material Vbetween the shell and the pile shall not extend upwardly far enough to raise the sandchecks away, from their normal positionagainst the pile. Ifthis latter situation were permitted to develop the sand; with which the tube is subsequently lled would be less securely contained within the tube andless of its weight would be transferred through the sand checks to the shield. If, upon inspection of the bottom,`it was determined that the bottom was so soft that the shield under its own weight would settle a distancegreater than the length of the normal skirt, then it is anticipatedthat a longer skirt would be used-in such a situation.

The mechanism thus rfar described is obviously adequate to holdal column ofisand about a pile, escape at the bottom being prevented by the depthj of penetration of the lower end of the tube.` However, it is necessary to make provision for the situation that develops when the mudline is lowered as the bottomis washedY away. As has been pointedy out before; the deptnto which the shield sinks; in the bottomA is determined by the nature of the bottom. All bottom material is ina,- more or less fluid stateand,y offcoursais thoroughly saturatediwith water. At the position of equibrium, it is, apparent that the bottom material under the shield stops further descent when the lateral support offered by the adjacent bottom material is equal tothe outward; force exerted by that portion of the bottom which is immediately below the shield. When the surface material is washed away as at 6'2v in Fig. 14 it is apparent thatv the lateral support accordedv the bottom material `located at 64 in Fig. 13 is largely eliminated with the result that the materialy 64 of Fig. lS'moves laterallyto the position shown in Fig. 14. With this portion of the bottom dis,- placed-the loaded shield moves downwardly until a new position of equilibriuinis reached as shown in Fig. 14. Naturally this gradual settling of the shield is a continuous process which takes place as rapidly as lateral support oiY bottom materiall 64A is removed to an extent suiiioient to permit.' the supporting material to shift sidewise. The heavy load imposed on the shield through the sand checks is always adequate to keep the lower.` edge of the shield asuilicient dis- 75,`

tance in the bottom to eliminate any possibility of escape of sand. i

If the bottom'is particularly hard so that the lower edge is capable of penetrating only a short distance, I have found that the seal formed by the bottom material that extends upwardly within the skirt and the sand that may filter past the sand checks' toy flll the space beneath the segments, is capable of preventing leakage of sand from the shield, regardless of changing bottom conditions.

Where the bottom is sloping, the action explained above will also prevail and this` is illustrated by the showing in Figs. and 16 in which case the bottom material 66 has been washed away causing failure of lateral support for material 68 which under the pressure of the shield is forced laterally to the position shown in Fig. 16, thus permitting the bottom edge of the shield to remain embedded in the bottom.

v Theprinciple involved in the act-ion just described is illustrated by the common experience had when one is standing in the surf on asloping vsand beach.y The feet settle a certain distance in the sand until a position of equilibrium is reached.

If the sand about the ankles is then washed away the feet Awill again settle a distance approximately the same as that obtained in the first position of equilibrium.

During the winter, the ice present in northern harbors tends to damage the upper sections which, as stated are of sheet material. If this situation develops I have devised a means and method of making repairs in a simple manner. The damaged portions are removed from the shield by merely drawing them upwardly from the section below, unbolting the joint and removing the shield from the pile. Because of the fact that, when initially installed, the telescoping ksections t quite snugly, it has been found dinicult in inserting a new sectionto secure a satisfactory t if vusing a section similar to the original. Instead I have found it more convenient to use a unit similar to that shown by section 10 in Fig. 19. 'Ihis section has afunnel-like bottom, the smallest portion of which is substantially smaller than the upper end of the section into which it is to be inserted, but then broadens out suiiciently to limit the distance it may penetrate the section below. In thel use of this section l0, I merely'position it about the pile clamping the longitudinal joint together as in Fig.` 2, and then lowering it down on the top remaining section of the original shield. Then, by pouring into section 1l! additional sand, the shield is in condition to carry on until it may be again damaged bysubsequent winters.

-Fg. illustrates a modified means for supporting one section on another. Instead of using the external hooks shown in Fig. 4, I have used internal hooks 12 which have, extending diag-Y onally upward therefrom, the spacers 14. The hooks 12 are secured to section Eby spot welding or in any other-convenient manner and these hooks are spaced at such distances about the inner circumference of the section that they will be adequate to prevent the pile positioned within from touching the shield at any point. The spacers 14 operate in the same manner and have the same functions as' spacers 2D heretofore described. This method of supporting the section provides adequate flexibility at the joint as was the case when using the hooks of the types shown in Fig. 4. Fig. 21 is a section on the line -2l--2l of Fig. 20 showingthe manner in which .before the distance between ber adapted to be the spacers prevent the pile from touching the wall of the shield.

By having a skirt of' proper length, displacement upwardly of the sand checks by the bottom when the shield is initially lowered into place, is prevented. This is essential, for, if the segments were swung upwardly .and disengaged from'the pile, lateral shifting of the shield will take place. Obviously it takes but little movement sideways the pile and shield at one point will exceed the length of ar segment, and should this happen, the sand when poured in would force that segment unsupported by the pile, downwardly below the horizontal, thus creating a large void through which the sand ycould readily escape.

From the foregoing description of preferred forms of my invention it will be seen that I have provided an effective means for preventing destruction of submerged piling my amphipod Crustacea or other marine animals. In addition my structure is easy to make and install and the cost is far below that of installing a new pile. I have also provided a device which constantly maintains the sand sealed within the tube regardless of changing bottom conditions. distinctly understood, however, that I do not intend my invention to be limited to the precise forms shown but only by the appended claims.

I claim:

1. A pile shield comprising a plurality of ilexibly connected tubular sections, a sectional bottom for said shield comprising a plurality of overlapping segments exibly vconnected to said shield, auxiliary means for urging said segments downwardly whereby a pile positioned within said segments will be centrally located with respect to said shield and a skirt extending below said segments a substantial distance whereby peneof the bottom by said skirt when said will not exceed the distance to said segtration shield is unloaded from the lower edge oi said skirt ments.

2. A 'pile shield comprising a tubular mempositioned about a pile, means for retaining loose material comprising a sectional bottom, said bottom formed from a plurality of inwardly extending overlapping segments flexibly connected to said shield, auxiliary means for urging said segments downwardly, and a skirt of substantial length extending below said bottom.

3. In a pile shield, a segmental bottom closure means comprising a plurality of segmental sections hingedly connected to said shield, said sections alternately overlyingy and underlying each other, the underlying sections having their radial edges rounded downwardly.

4. A tubular section for use with a pile shield comprising a tube formed of sheet material, means at one end of said section for maintaining said section in telescopic relation with the end of an adjacent section, and spacer means extending internally of said section to prevent a pile about which said section may be positioned from touching the inner wall of said section, the distance each said spacer means extends in'- wardly from said/section Wall being such that twice said distance plus the diameter of said pile is .less than the internal diameter of said section.

5. A pile protector comprising a tube, means for maintaining the lower edge of said tube continuously embeddedin the bottom in which said pile is positioned regardless 'of changes in the within said shield I wishit to be adjacent bottom formation, said means cornn prising a bottom closure member kof 'VariabIeinternal diameter attachedv to said tube and ,closing the space between said tube .and .said-pile land positioned a substantial distance abovealthe lower end. of said tube, and meansforxurging said tube continuously downward comprisingfa quantity of i'inely dividedloose material .positioned between said tube and pile, thefweight-.of .which is substantiallycarried by saidffbottom.

6. A pile shield comprising 4a tubularsmember, a variable area closure member connectedtorsaid tubular member, said tubular memberrhaving a skirt extending a substantial distanceobelowfsaid closure member, and a plurality of internally aextending spacers attached to saidiztubuiarz'member, said spacers being of insuicient. length to centersaid pile with 4respect to Ysaid tubular member, lbut of such length and frequency to .prevent vsaid lpile iirom touching said Atubular member between said closure member and a-:predetermined'point above.

'7. A pile shield comprising a plurality oitubular sect-ions mounted one on the other to form an articulated tube, each section being/divisible throughoutits length, the top of one section cooperating with the bottom of the-section immo-- diately above to produce a Vtight but Aflexible joint, a plurality of internally extending, circunr- `be vpositioned about a pile, means for closing the space between said shield and pile near the bottom of said shield,-means for holding the lower end of said shield substantially concentric with said pile, askirt attached to the lower end of said shield, said sections and skirt being substantially unobstructed longitudinallyon their outer surfaces whereby the shield may settle into .the bottom material under its own :weight to a point of equilibrium, said closure'means `being :positioned a sufficient distance above fthe lower edge of said skirt `so as tobe unaffected by said bottom material when said shield has reached said position of equilibrium.

9. The combination of a pile embedded in bottom material and a shieldpositioned thereabout and spaced from said pile by finely divided inert shiftable ,materiaL 'the lowerend lof said shield being embedded in said bottom material, closure `means attached to said Ashield and separatingsaid bottom material that is within vsaid shield and said nelytdividedimaterial, the combinedweight `ofsaid shield and iinely dividedinert-material being4 sucient to move said shield andsaidima terial downwardly` along said pile when a certain amount lof bottom material surrounding said shield.l but above the lower endl of saidv shieldhas been removed.

10. Apile protector comprising a tube, means yfor maintaining the loweredgeoi said-tube continuously embedded in the bottom in which said pile is positioned regardless of changes in the adjacent bottom formation, said means comprisying a bottom closure member of variable'internal diameter andmeans for constantly urging said member to assume-aposition of maximum area wwhereby it will lit closely and movablyathe f pile about which said protector may be positioned,

saidfbottom closure Vmember positioned a suiiif-cientdistance above the lower edge of said tube n so as to be unaiected in` an upward direction'by @5 bottom material within said tube when said pro- `tector has settled to a point of equilibrium under Vthe inuence of its own weight, and meansior 'moving said protector a-further distancel down said pile to `a: point of yequilibrium at which thel lower edge of said tube will always be embedded in the bottom materiaLsaidmeansvfor moving said protector comprising a quantity of nely di- `-vided loose-material positioned betweensaid tube and pile the weight of which is substantiallycarl5 .ried by saidbottom member.

.11. A pile protector comprising a tube having its outer surface substantially unobstructed and its lower end adapted to penetrate the bottom" in which said pile is embedded, closure means con-"520 nected to said tube for tightly but slidably `closing the space between said tube and pile, said closure means being positioned a 4substantialidistance above the lower end of said tube whereby`A bottom material may form a seal within the lower '-25 end of said tube when said lower end is embedded Ain the bottom, means for moving said tube and vsealing material downwardly along said pile* upon the lowering of the bottom material surrounding said tube, said means comprising a quantity of 730 finely divided loose material positioned within said tube and exerting its weight through said closure means, the effective downward force exerted by said tube and contained loose material always exceeding the frictional force existing between said' closure means, loose material, and

12. Means for retaining loose material about the ysubmerged portion of apile comprising a tubular member positioned about said pile endg@ having its lower end arranged at an angle to ap- ...proximate the=slope of the bottom, said tubular vmember having a bottom closure member of bottom to a `position of equilibrium under the influence of itsown weight.

13. A shield" comprising a plurality of flexibly connected sections adapted to be positioned about Va pile-and to ,extend downwardly into the bot- 755 tom a suitabledistancathe lower .section of said shield comprised of aplurality ofdivisible` parts, each part having associated therewith movable Vmembers adapted to close the annular area be- `tweenrsaid pile and lower section, said members 60 being positioned a substantial distance above the lower end of said bottom section, each upper section comprising `a divisible tubular member, each upper section supported on the section below vby -a plurality of supports spaced about the lowercircumference of each section, a plurality of .internally extending'spacers associated with each upper section, the distance between said spacers lbeing'such as to prevent'said pile from engaging'the walls of said sections :at any point, 70 said spacers `extending inwardly .a distance insufcient to center-said pile with respect to `said sections.

14. A protective device for a partially submerged pile comprising .a tube about said pile being embedded a substantial distance in the bottom so that the bottom material forms a seal at the lower end of said tube, a bottom closure member of variable internal circumference associated with said tube, said closure member posi-v tioned a sufficient distance above the lower edge of said tube so as to be unaffected by bottom material within said tube` when said device has settled'to a point of equilibrium under the influence of its own weight, loose material `substantially iilling the space between said tube and pile, said tube through said bottom member as sisting in carrying the weight of said loose material, the combined weight of said tube and said loose material being suiicient to maintain the lower end of said tube embedded in the bottom `and to move said tube downwardly along said pile as surrounding bottom material is removed.

15. A method of protecting a pile comprising the steps of placing a tubev about said pile, centering said pile with respect to said tube at its lower end by means` closing the annular area between said pile and tube, embedding vthe lower end of said tube in the bottom to a depth less than the distance from the bottom edge to said closure means, "and iinally lling the space between said` pilev and tube with finely divided shiftable inert material, thereby causing said tube and inert material to move downwardly about said pile a furtherv distance to a point kof equilibrium. I

16. In a pile shield of tubular form a bottom closure means comprising alplurality of overlapping segmental sections, each section movably connected to the Wall 'of said tube whereby each segmental section may be 'moved through a substantial arc, each of said segmental sectionsr overlapping adjacentsegmental sections, means for preventing movement of said segmental seev tions below a position substantially transverse oir saidk tube, and auxiliary means urging said sections toward said transverse position.

i i JOHN UPTON.

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