US2308793A - Pile shield - Google Patents

Description

J. UPTON PILE SHIELDy '.Ian. 19, 1943.

Fil-ed Nov. l24, 1959 4 sheets-sheepY 1 orney Jan, 19, 1943. J, UPTQN 2,308,793

PILE SHIELD FiledfNoV. 24, 1939 4vSheets-Sheeb 2 dan, "19, 1943. J, UPTON 2,308,793

PILE SHIELD Filed Nov. 24, 1939 4 Sheets-Sheet 3 Patented Jan. 19, 1943 I ILE SHIELD John Upton, Cambridge, Mass., assigner, by

mesne assignments, to Anderson Products, Inc., Cambridge, Mass., a corporation of Massachusetts Application November 24, 1939, serial No. 305,833

12 claims. (c1. 61-54) This invention relates to means for protecting marine piles.

It is well known in many of the harbors of the world that the piling supporting docks and other harbor structures 'is being seriously aiected by the inroads of certain marine borers, particularly the cl1el1ura,limnoria and teredo.

The progress of these borers along coastal waters is surprisingly rapid, and the rate of destruction of piling is likewise rapid after infestation has taken place.

It is customary for these borers to attack the piles throughout the entire length between the mud line and high water mark. Through the use of test blocks which are now maintained through cooperative action by dock owners the situations prevailing in different harbors are well known. Where the attacks are developing inseriousness, consideration must be given to means for protecting the piles or replacing them when damaged too badly, and it is obvious that this is a serious matter, as the number of piles in use is tremendous and th cost of replacement great.

This invention is primarily concerned with providing a means of protecting the pile against attack, or if attack has started, of checking the progress of the borers and preventing further damage thereafter.

In my earlier patent for Pile shield, 2,181,526, issued November 28, 1939, I have disclosed the broad invention of a pile `shield suitable for this purpose, and this present application is particularly concerned with improvements thereon.

In the above named application it was contemplated that the tubular outer shield could be made of any suitable material and in any convenient form. Through experimentation and practical tests I have evolved a particular type of tubular construction which is both economical, easy to assemble, and which, because of the cheapness of materials of which it is made, offers no temptation to harbor thieves.

In addition', the particular closure means at the lower end of the shield, or sand checks as they are generally referred to, has been made in anew portion broken away to show the relationship of the sand checks withthe pile.

Fig. 2 is a section on the line 2-2 of Fig. 1 showing the relationship of the staves and connected parts at a joint.

Fig. 3 is a plan view of the bottom section of the shield carrying the sand checks, the section being shown in two halves and hinged for ready application to the pile.

Fig. 4 is a perspective of one half of the lowest sand check carrying section.

Fig. 5 is a fragmentary section on the line 5-5 of Fig. 4, showing in addition a spring restrainer.

Fig. 6 is a detail of the stave construction showing the means for assembling and interlocking the stave sections at the joints.

Fig. 7 is an elevation of one half of the bottom section carrying the sand checks, the sand check construction being the same as that shown in Figs. 1 and 3.

Fig. 8 is a perspective illustrating the supporting band on which the sand checks are mounted prior to attachment to the staves.

Figs. 9 and 10 illustrate sand checks formed as a group from single sheets of material. 5

Fig. 11 is a perspective view showing the sand checks of Figs. 9 and 10 in assembled position prior to application to a pile.

Fig. 12 is a modied form of sand check construction.

Figs. 13 and 14 illustrate sand checks formed as groups from single sheets of material, but including in addition spring backer plates.

Fig. 15 shows a complete group of sand checks and backer plates formed from a single sheet of material and adapted to be folded to finished form.

Fig. 16 is a. fragmentary perspective showing sand checks made according to the disclosure in Fig. 15 in finished form with the springs in position.

Fig. 17 illustrates a modification of the supporting band prior to forming.

Fig. 18 is a fragmentary perspective of the sup- 21 is another form of sand check. 22 is a section on the line 22--22 of Fig. 21. 23 is still another modication of. sand 24 is a section on the line 2li- 24 of Fig. 23. 25 is a further modification of sand check.

Fig. 26 is a section on the line 26-28 of Fig. 25.

Referring now to the drawings, in Fig. 1 is shown a pile 2, partially eaten away by the marine borers, embedded in the bottom 4 and supporting a superstructure 8.

As the object of this invention is to stop the destruction of the pile in accordance with the method disclosed in my pending application, Serial No. 157,709, I contemplate in this present case 'positioning a generally similar structure about the pile, which structure consists of a tubu'-, lar shield 8 having a bottom closure means I8, which closure means is composed of members referred to as sand checks.

This structure, the lower end of which vis embedded in the bottom as at l2, is filled with sand -M which acts in a two-fold manner; first, to seal the pile from the surrounding water, rendering the water conditions at the pile stagnant, there- -by eliminating the oxygen supply on which the continued existence of the borers depends; and

l sand.

The tubular shield 8 consists of a plurality` of sections, there being a lower section I8 which carries the sand checks. an intermediate section I8, and an upper section 20. There may, of course, be additional sections, depending on the length of the pile and also on the length of the sections. These matters of dimensions are primarily one of convenience. The connection between the sections is such that there will be a certain degree of flexibility so that if the pile is bent, the shield may bend with it.

Referring now particularly to the lower section I8 which carries the sand checks, it will be seen that this section consists of a plurality of short section staves 22, of which in the present instance there areAtw'elve used ina complete circumference. When the staves 22 and sand checks forming the lower section are in position about the pile, they are bound circumferentially by a hoop 2Q having any suitable takeupmeans, as, for example, an adjustable bolt connection shown at 26 in Figs. 1 and 2. 1

The length of the section staves 22 is such that when the sand checks are in position thereon, an appreciable length of stave will extend below the sand checks for purposes that will be described hereafter.

In the preferred form the lower section I8 is made in'two halves, each half consisting of six section staves 22 which are held together through the metal unit that comprises the sand checks themselves and the sand check supporting band 28 shown plainly in Figs. 7 and 8. That is, the sand checks are mounted on the supporting band 28, and to this band by suitable screw means 28 or otherwise the section staves 22 are attached.

It should be pointed out here that the number of section staves in a circumference and the number of sand checks may be varied as found convenient, but in the typical case it has been found that the use of twelve staves and twelve corresponding sand checks constitutes a satisfactory construction. i

In Fig. 3 the Vsection staves 22 are shown in end view. and it will .benoted that each of the staves is milled along its longitudinal edges in uniform manner so that there may be suitable interlocking xbetween the adjacent staves without,

volve angles which will result in edge formations which may not be easily chipped or cracked oil. and at the same time. the interlocking must be sufficiently substantial so as to prevent the. escape of sand contained within the shield.Y

The tongue and groove construction used in connection with the staves of the lower section is also used in connection with the stave formation of all of the other sections. This uniformity results in ease of manufacture and interchange, ability of the staves.

Further details of the stave construction are shown in Figs. 2, 4, 6 and 7.

The sand check construction to which staves 22 are attached is as follows. The sand check supporting band 28, shown in Figs. 7 and 8, consists of a continuous strip of metal bent into a generally semi-circular por-tion to form six sides vof a length approximately that of the width of the section staves. The supporting band 28 may be made from -a single piece of metal by notching the upper edge at suitable places and then bending .fthe upper portions through ninety degrees .to form horizontally extending flanges 30. These flanges may be held together at their abutting ends by the band stifl'eners 32, which may be spot welded in place on--the under side of the iiange joints. Other means of connecting the flanges 20 to provide the necessary s'tiifening maybe used, as, for example, by bolting band stiiieners 32 in place, or a construction as shown in Figs. 17 and 18 may be used, in winch the flanges 38 instead of being notched as in Fig. 8 are merely slit,as at 21, and then bent along the diagonal lines 3| to give the formation shown in Fig. 18 after flanges 30 have been bent downwardly to the horizontal. Bolts or rivets may be inserted through the holes 33 to maintain the triangular portions firmly together, or these areas may be spot welded -if desired.

In this way a supporting band is made which isv very rigid and well adapted to carry the loads imposed thereon, but it is to be understood that the construction of the supporting band 28 may be modified as seems convenient, as long as i-t results in a structure to which the staves and sand checks may be attached.

The sand checks proper are designated as 34 in the several views. All of the sand checks are preferably stamped from sheet metal and may be uniform in dimensions. The rear end of each sand check is substantially the length of one side of ythe supporting band 28, and, of course, substantially the same Width as the section stave 22. Each sand check tapers -to a narrow front end, as at 36, and has along its edges triangularly shaped wings 88. 'I'hese wings are plainly shown in Figs. 3, 4, 5 and 7. When in position yeither off or on :the pile, the sand checks'overlap, and in the case of the overlying sand checks the wings 38 bend upwardly, while with |the underlying sand checks they bend downwardly.y The wings have a strengthening effect, adding to the rigidity of the sand checks 'and at the same time facilitating the sliding of the checks one over the other by providing a rounded edge at the line of engagement between the sections.

The sand checks are attached to the supporting band 28 through members which I'call hinges,

as at 48. `These hinges are straps of metal appropriately bent and welded .'to the sand checks on the latters upper surface.` 4As can be seen in however, tending to split away the edges of the Vlli Fig. 4,.two hinges 40 are attached .to each ysand check, and these hinges extend downwardly therefrom, back of the vertical portion of supporting band 28, around the bottom thereof, and bend upward in hook fashion. as at 4|, to terminate against the lower inner surface of the supporting band 28. The material of `which hinges 40 are made is such that the sand checks may be moved upwardly through an arc with sufficient v checks so that Ithe latter may l-n -turn force down not only the checks against which they rest but also the underlying sand checks which are in engagement with the overlying members.

The springs 42 are preferably in the form shown, but obviously they may take other forms if found convenient or desirable. In Fig. '7 the springs 42 are attached directly to the staves 22 by staples 44, and this is the construction generally used when the lower section I6 with the sand checks therein is -assembled at the factory for shipment to the job. In some cases, however, I have found t-hat it is more desirable to assemble the sand'ohecks in relation to staves 22 right on the job so that the staves'may be shipped directly thereto in quantity from the lumber mill while the sand checks are assembled on the supporting band at another plant.

When this situation prevails, in order that the springs may be mounted and operative ragainst ythe Vsand checks, I have provided the form shown in Figs. 4 and 5 in which, in addition to the supporting band 28, a backer plate 46 is added. There is a backer plate positioned behind each overlying sand check. This backer plate is secured to the supporting band 28 by spot welding or otherwise, and the spring 42 is clipped in position on the backer plate, as at 48. Thus the entire sand check unit may be made apart from the staves and at -the point of use the staves may be quickly attached to the sand checks lthrough the use of screws, nails or any other convenient attaching means.

However, whether the lower seotion I6 is assembled at the factory bef-ore shipment tothe job or whether it is assembled at the job, the finished units operate in identical fashion.

As shown in Fig. 3, the two halves of the lower section are ordinarily hinged together by what I have termed a base hinge 50 which is merely in this case a metal strap nailed to or screwed to the outside of the adjacent staves of the two halves. In practice the vertical dimension at the midpoint of hinge 50 is somewhat less than the vertical dimension of the side portions that are attached to the staves, so that there may be easy flexing of the hinge, but at the same time there will be an adequate area of metal to provide sufficiently rigid attachment to the staves. If desired, the edges of the attachment portions may be formed into flanges as illustrated in Fig. 7 at 5I. Other forms of hinges could, of course, be used, provided they were of adequate strength and flexibility. The number of hinges holding' the two halves of the lower section together may 'be increased to as many as may seem expedient.

Having the halves hinged in this fashion facilitates application of the lower'or base section IB to the pile. The section is opened in the manner shown in Fig. 3, positioned about the pile, and then drawn together through the use of hoop 24. When thus secured about the pile the sand checks will be forced upwardly through an arc to assume the position shown in Fig. 1. The

arc through which they will move is determined by the 'diameter of the particular pile, and of course this angle will shift slightly as the sand checks are slid downwardly along the pile to the final position of repose. In any event, the sand checks are continuously urged inwardly and downwardly by the springs 42 so that the inner ends of the checks tightly engage the circumference of the pile, and of course, in this position the checks overlap continuously to form av substantially' sand-tight closure means toward the lower end of the shield.

To facilitate installation of the base sections I6 it is desirable that the pressure of springs 42 against sand checks 34-be relieved so that the sand checks may more readily be swung upwardly into installed position against the pile. To this end I provide spring restrainers 45 as in Fig. 5 having hook members at either end, one of which may engage the cross bar of the spring and the other may engage a staple 43 driven into the upper end of stave 22. After installation of the base sections has been completed. spring restrainers 45 are removed, allowing springs 42 to engage the appropriate sand checks 34, and staples 43 are either removed or driven down into the end of staves 22.

The dimensions of the shield and sand checks may be varied, depending on the size of the piles with which they are to be used, but from experience it has been found that piles run within such limitation that in most cases a single size of shield and sand checks will suffice to protect the big bulk of the piles now ln use.

, In positioning the lower or base -section I6 with the sand checks about the pile, it is customary to do this at or above the water level. Thereafter, as additional sections are added above, the lower section is gradually forced downwardly along the pile until the lower edge l2 has penetrated the bottom a suitable distance and the unit has reached a position of equilibrium.

After the application of the base section to the `pile it is then necessary to apply the upper sections. These upper sections are formed as follows. Each upper section consists of a plurality of section staves 52 of the same number as those in the lower section I6. The section staves 52 shown in Figs. 1, 2 and 6 arethe same width as the short section staves 22 and have the same tongue and groove formations along their longitudinal edges.

To the lower end of each section stave 52 is attached on the outer side a guide stave 5H and on the inner side a finger stave 56. The guide staves 54, as can be seen in Fig. 2, are somewhat.

tween the sections.

The guide staves 54 and finger staves 56 are for the purpose of positioning section staves 52 on the previously assembled section immediately below, and they are adequate to maintain the section staves in position as the latter are placed one at a time upon the upper end of a corresponding lower section stave.

Thus, in assembling the intermediate section I6 on lower section I6, a section stave -52 is placed end to end with one of the lower section staves 22, where it will be held in position through the engagement of guide stave 64 and linger stave 56 with the outer and inner sides of section stave 22. The arrangement of parts prior to engagement is shown in Fig. 6. All of the section staves of intermediate section I6 are thus positioned on the upper ends of the corresponding section staves 22of lower section i6 until the circumference is complete. Then, through the use of hoop 56 about the guide staves 54, the two sections are bound together. y gagement of the sections, however, is such that the lateral flexibility at the joint is adequate to take care of any movement of the pile.

Having assembled intermediate section I6, the two completed sections are now forced further down the pile and the upper section 20 is added. The procedure followed is the same as that already described, namely that the section staves 52 of the upper section are applied through the use of guide staves 54 and finger staves 56 to the section staves of intermediate section I6, and after all of the staves of the new section are in position, they are bound firmly in place through ment of voids. If these finger staves 56 were not so employed, voids would occur immediately below the point of contact between a. pile and the inner side of the shield, thereby providing an unprotectedarea favorablefor further borer adequately strong to carry the load. imposed by the use of hoop 60 about the next group of guide staves 54.

If it is found that the sections thus providedy give sufficient length to the shield to bring the upper end above the highest point of borer attack while the lower end is embedded in the bottom as shown in Fig. 1, the shield may be considered adequate for the purpose and the uper ends of section staves 52 are then bound together by the use of hoop 62. In this way a construction substantially sand tight and sufficiently strong is provided. Sand is then poured into the shield, displacing the water within and coming t'o rest on the sand checks 34.

Obviously, as the sand fills the shield more and more, the pressure on the sand checks Awill become greater. The increasing weight tends to slide the sand checks downwardly along the pile, but as they are connected to the shield itself through the medium of supporting band 26 attached to the lower section staves 2'2, the result is that the sand checks and shield are forced downwardly along the pile and the lower edge I2 is driven further and further intothe bottom until a point of equilibrium is reached. Since the lower end is sealed, such sand as may filter through the sand checks will be trapped thereunder, as at 64, and escape prevented through the bottom material, as at 66, which has been caught within the lower end of the penetrating shield.

As previously pointed out in my earlier Patent No. 2,181,526, the shield will move downwardly along the pile to a new point of equilibrium if the supporting bottom material is washed away to any degree, but the lower edge l2 during this period of movement will always remain embedded in the bottom so that escape of sandis prevented.

. The finger staves 56 also act as centering means A the sand within. 'Ihe section stave 52 maybe of any suitable length, it merely being necessary that under the internal pressure imposed by the sand no opening be created between Vthe staves. If there is any tendency for the staves to spread apart, additional bands, as 62 and 63 shown in Fig. 1, may be provided to maintain sand--tighti joints.

'I'he tongue and groove constructions shown are of importance, and I have found that sand may be adequately retained and the section staves held together along their edges through the use of an edge construction consisting of one shallow, longitudinal groove and a tongue substantially the reverse of the shallow groove just referred to, so that in effect the engagement between its adjacent edges constitutes a double tongue and groove formation, eliminating entirely any likelihood of the breakage of the tongues.

Thus, referring to Fig. '4, the groove along one edge of section stave 22 is indicated at 66, while the adjacent tongue is shown at 10. On the other edge of the same stave the -groove formation is at 12 and the tongue formation at 14. For ease in manufacture, the sides of the tongues and grooves are flat surfaces, but they might be curved if preferred. At any rate, the general angle formed by the sides converging at the bottom of the groove and at the top of the tongue is obtuse. passage of sand about the corners. In a preferred construction the angles of the sides of groove 66 and tongue 14 are at 135 degrees, while the angles of the sides of tongue 10 and groove 12 are at 105 degrees.

In Figs. 9, 10 and 11 is shown a modified form of sand check construction. In this structure the sand checks instead of being formed individually are formed as a group by cutting them from n. single sheet of material. Thus, in Fig. 9 the sand checks 16 are connected together and integral with the band 16, The length of band 16 is such that when it is suitably bent at the dotted lines 80, it will fit Within the multiple sides of the lower section of the shield. 'I'he checks 16 are of substantially the same size as the individual checks 34, previously described. These checks are to be bent downward when in adjusted position along the lines 62 and the wings 64 are to be bent in the same manner as the wings of the individual checks.

In Fig. 10 is shown the other group of sand checks,rwhich, together with theV structure of Fig. 9, constitute a continuous group. In Fig. l0 the/sand checks, designated at 66, are similar to checks 16 except that they are staggered in relation thereto so that the groups when overlapped will provide a complete closure. Checks 66 are integral with the connecting band 66, 4which band is a trifle shorter than band 16, so

that whenthe two bands are bent at lines 66 and 66 to form the construction shown in Fig. 11,

I'he angularity also minimizes the.

they will nest together properly. Both bands 'f may preferably have holes 80 punched therethrough forready attachment to the section staves 22. f

The assembled construction is shown in Fig. 11, in which the two bands 18 and 88 overlying each other form the equivalent of the sand\checl supporting band 28, previously referred to. The bands may be conveniently attached to section staves 22 by screws 82 inserted'through holes 90. The sand checks 16 and 86 are underlying and overlying respectively and urged downwardly by the coil springs 42 which are in engagement with the overlying checks 86.

If necessary, to prevent the sand checks from being forced below a horizontal plane, which is the desirable position for them to assume prior to application to a pile, stops, not shown, may be provided.

The individual sand checks 34 or the checks 16 and I6 formed as a groupmay have their ends serrated, as at 94 in Fig. 12. This construction is occasionally found advantageous where it is desired to insure against any upward movement of the shield after installation on a pile, before the sand is placed therein. The teeth 94 dig tightly into the pile upon any attempted upward movement and thus guarantee maintenance of position at the lowermost` point reached.

Other sand check constructions which may be provided are shown in Figs. 13 to 16 and Figs. 19 to 26. It will be observed in Fig. 4 that it has been considered desirable to provide a backer plate 46 associated with the supporting band 28 so that the sand checks and springs may be assembled as a unit prior to attachment to the staves.

In Figs. 13 and 14 and Fig. 15 a modification of this construction is shown. Figs. 13 and 14 taken together constitute a group of sand checks which will form one half of the total number required. Sand checks in Fig. 13 are connected integrally with band |02, while sandchecks |04 in Fig. 14 are connected integrally with band |06. Band |02 has additionally connected thereto the upwardly extending backer plates |08 which serve the same purpose as backer plates 46 shown in Figs. 4 and 5. That is, when sand checks |00 and |04 are combined, checks |00 will constitute the underlying checks, while checks |04 will be the overlying checks, and springs 42 may be attached to backer plates |08 to exert a downward force on the overlying checks |04.

In this manner sand checks may be assembled complete and ready for use, including the springs, prior to attachment to the lower section staves. Holes ||0 and |l2 are provided in bands |02 and |06 through which attaching means may extend to connect the bands to staves 22. Band |06 is slightly shorter than band |02 so that when bent along the vertical dotted lines the two will nest together properly.

A still further modiiication of sand check construction is shown in Fig. 15. This construction results in substantially that provided by the forms of Figs. 13 and 14 except that the sand checks and backer plates are all from one sheet of material. Thus, sand checks ||4 and backer plates ||8 are connected integrally with band ||6. Sand checks |20 are integral with band |22, and in addition bands ||6 and |22 are integral with each other.

In the formation of this unit band |22 is bent upwardly along line |24 until it rests against band ||6. Sand checks ||4 and |20 are then bent downwardly along lines |26 and |128 to a position at right angles with bands ||6 and |22.

Sand checks ||4 are the underlying'fmembers,

while sand checks |20 are the overlying members adapted to receive the downward pressure of springs 42 which may be attached to backer plates ||8. I

A fragmentary perspective of the completed construction is shown in Fig. 16. The construction, of course. includes suitable holes |30 through the bands through which connecting means may pass to the staves. Other holes |32 in the backer plates are provided for additional securing means.v

By this construction economies in production may be 'eiected inasmuch as the entire unit may be stamped in one operation from a single sheet of material. Having bands ||6 and |22 integral provides additional ,rigidity when the unit is in completed folded position.

It is understood, of course, that the wings, indicated as |34 in Figs. 13, 14, 15 and 16, will be bent upwardly in the ca se of the overlying sand checks and downwardly in the case of the underlying sand checks, so that there may be easy movement of the checks against each other as they are swung upwardly through varying arcs when in engagement with the pile, coupled with the necessary rigidity.

In Figs. 19 to 26 are shown a number of other modifications of sand checks which may be used. One of the principal requirements in a sand check is that it be strong against transverse bending, because the load imposed on-each checkl by the column of sand is considerable. In all of the constructions heretofore described the wings 38 and |34 provide flanges which greatly increase the rigidity of the checks. Other forms of flanges and other means' for strengthening the checks are shown in Figs. 19 to 26.

In Fig. 19 the sand check |36 has wings |38 in the 4form of segments of a circle which arey bent upwardly from the plane of the sand check proper, as shown by the section in Fig. 20.

Another form of sand check is shown in Fig. 2l in which the sand check proper |40 is made of a sheet of corrugated material, the corrugations extending longitudinally of the check and of uniform dimension throughout the length. In addition to the corrugations which give increased rigidity, segmental wings |42 are provided of suicient area to materially add to the rigidity. A cross-section of this construction is shown in Fig. 22.

Still another form is shown in Fig. 23 in which the sand check |44 is corrugated, as can be seen by the section in Fig. 24. 'I'hese corrugations, however, decrease in width from the wide to the narrow end so that the same number of corrugations of proportionately changing dimensions are presentthroughout the length of the check. The rounded downwardly extending outer edges of the corrugations, as at |46, provide a straight longitudinally extending surface adapted to engage an adjacent sand check of the same construction but in inverted position to provide a sand-tight joint with a minimum of friction when the two are moved relative to each other.

Another form of sand check is shown in Fig. 25 in which the sand check |48 has wings |50 in the form of generally trapezoidal areas bent upwardly at suitable angles as shown in Fig. 26 to provide the additional rigidity necessary.

It can thus be seen that I have provided a com struction adequate for the purpose, easy to install, adapted. to be made in quantity production and of materials so cheap and relatively valueless that they will not be subject to theft by harbor thievesj which is often the case whereshields of metal are used.

The shield may be increased in length to provide protection for longer piles, and furthermore, any damage to the shield may be easily repaired through the installation of new individual section staves.

I claim:

1. A pile shield comprising a plurality of sections, each section comprising a plurality of vertically extending section staves, each section stave except those of the bottom section being positioned over a corresponding sectionstave of the section below, each section stave except those of one section having attached tov one end an outer guide stave and an inner finger stave whereby each of said section staves may be individually positioned upon lower section staves, and means for binding the section staves of each section together to form a completed tubular shield.

2. A pile shield as set forth in claim 1 in which the engaging vertical edges of the section staves are formed to have a shallow groove and a low tongue along each edge of each stave, ad-

jacent edges of adjacent staves being adapted for interlocking engagement.

3. A pile shield as set forth in claim 1 in which the lowest section of said shield has attached about its inner circumference a bottom closure member of variable internal diameter and adapted to close the space between said shield and a pile about which it may be positioned. A

4. A bottom closure unit'for use with a pile shield, comprisingv a multi-sided supporting band, a plurality of overlying and underlying sand checks hingedly `connected thereto, said supporting band forming horizontal anges acting as stops to check the downward movement of said sand checks in relation thereto, backer plates connected to the outer side of said supporting band at intervals and extending upwardly therefrom, a spring connected to each said hacker plate and arranged to exert a downward force against an overlying sandV check, said hacker plates and springs being in such number and so positioned that a downward force will be exerted against all of the sand checks of said u'nit.

5. A bottom closure unit for use with a pile shield, comprising a multisided supporting band having vertical and horizontal areas with the horizontal area, extending inwardly from the upper edge of the vertical area, a plurality of overlying and underlying sand checks hingedly connected thereto substantially to the point of junction between said vertical and horizontal areas the horizontal area of said band acting as a stop rality of segments to provide variable internal diameter attached thereto, auxiliary means for urging said segments downwardly, and a skirt of substantial length extending below said bottom closure member. said tubular member and skirt comprising a. plurality of sections Ypositioned -one above the other, each of said sections comprising a plurality of vertically extending individual section staves, each section stave except thoseof the bottom section, which includes said skirt, extending upwardly from a corresponding section stave of the section below, means attached to each section stave whereby each stave may be individually connected to a lower section stave, and means for binding the section staves and the sections formed thereby together to form a completed shield.

8. A pile shield comprising a plurality of flexibly connected tubular sections positioned one above the other and forming a line of meeting between each pair of engaging sections, each section comprising a plurality of vertically extending staves, .each of said staves having formations .along its longitudinal edges adapted to engage adjacent formations on adjacent staves to form a substantially sand-tight joint, means for connecting said sections together comprising a plurality of short outer staves extending circumferentially about each of the lines of meeting of said sections to form a substantially sand-tight closure at each of said lines of meeting, a pluralitv of short inner staves each of which is connected to the inside end of a vertically extending stave so`as to overlie the inner end of the corre- 1 sponding stave of the next section, and a bottom closure member of variable internal diameter attached to the section staves of the bottom section.

9. In a pile shield, a segmental bottom closure means comprising a plurality of overlying and underlying segmental sections iiexibly connected to said shield, auxiliary spring means connected to said shield above said sections and engaging certain of said sections on their top sides to urge said segmental sections downwardly, and means for rendering said auxiliary means inoperable during installation of said bottom closure means about a pile.

10. A bottom closure uni-t for use with a generally cylindrical pile shield and adapted to be secured 'to the interior circumferenceV thereof,

comprising a plurality of sand checks arranged in overlying and underlying relationship, the overlying sand checks being connected to a band shaped to't the said interior circumference,

the underlying sand checks being connected to a band shaped to fit the said interior circumference, the band to which each group of sand checks is connected being polygonal -in` shape i whereby it may fit within said shield of corresponding internal configuration, the outer boundary of each of said sand checks being substantially parallel to and substantially the same length as the segment of the band to which it is connected, the connection of said sand checks to said bands including neans to prevent` movement of said checks below the horizontal while permitting upward movement thereof.

1l. A bottom closure unit for use with a pile shield, comprising a structural and supporting member polygonal in form and having a vertical exterior surface, a plurality of sand checks arranged in overlying and underlying relationship flexibly connected to said member and'extending' inwardly therefrom to partially close the area within said member, stop means connected to said member for limiting downward movement of said sand checks below the horizontal, the outer l stantially parallel and substantially the same length as the segment of the member to which it is connected.

12. A bottom closure unit for use with a pile shield, comprising a. multi-sided supporting band, a plurality of overlying and underlying sand checks hingedly connected thereto, stop means connected to said band for limiting the downward movement oi said sand checks in relation thereto, hacker plates connected to said supporting band and extending upwardly therefrom, and springs connected to said backer`plates and arranged to exert a downward force against said sand checks.

JOHN UPTON.

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