US2598455A - Power hammer construction - Google Patents

Description

May 27, 1952 E. A. SMITH 2,598,455

POWER HAMMER CONSTRUCTION med June ze, 1951 2 SHEETS- SHEET 1 SHELL.

lN/ENTOR. 'EOWASDA-5MITH- May 27, 1952 E. A. sMn-H POWER HAMMER CONSTRUCTION O 2 SHEETS-SHEET 2 Filed June 26, 1951 INVENTOR. EDWARDA-5MII'H.

O )PM `ATTUf/VEI/.i

Patented May 27, 1952 UNITED svi- ATi-:s PATENT POWER HAMMER CQNSTRUCTIQN Edward A. Smith, Chatham, 1N. .1.,Yassgfnor 'to Raymond Concrete Pile Com-pany, iNeW York, .-N. Y., .a `corperation of NewJersey Application June 26, 1951SerialLNo.2,33620 (einigte.)

AThis invention -relates to power hammers particularly adapted, `among 4other possibilities, `for use in the installation of :piles Iand the like. 'The invention will be explained'in connection witha form of hammer adapted for driving hollow metal cores :such -as are placed inside cf lmetal pile shells Jfor driving the latter into place, but it-will be understood that various features ofthe invention are `adaptedior lother possible uses.

In vpreparing lto drive metal pile shells, itis the general -practice to vsuspend a hollow core from -the boom-of a crane, in a vertical position above the vdesired location of the pile, a -stea-m hammer vwith its -ram Aalso ybeing suspended 'above the core in `position to drive the core into -the earth while its lower rend y-is surrounded by vsucceeding sections of the pile shell. :When the vertical dimension of the conventional type of steam hammer is added-to the height ofthe usual pile lcore, it will be apparent that to secure the necessary head room for the assembly, it '-becomesnecessary -to use a crane withavery Along boom-and the Whole assembly becomes very cumbersome and inconvenient -to handle.

Heretofore in some instancesefforts have been made to provide va -more convenient assemblyrequil-ing `less head -room Aby using a single piston hammerfand ramof afsizevto twithin'the upperend ofthe core. However, such'an arrangement has 'two serious disadvantages, -rst, because lof the `necessity of using a steam cylinder small enoughito 'be received-within the limiteddiameter of the core, the `power -of "the hammerand the consequent-maximum possible Weight of the -ram are'unduly limited, fand secondly, such lsingle piston hammers can deliver yonly a limited -number of blows `per minute 'as compared -with the double piston-differential typesof hammers often used fior rapid'pile driving. For these '-reasons the assembly of a single acting hammer `within a core permits lonly comparatively slow pile driving, Withtheresultthat-such an arrangementis ordinarily 'useful only Aon vsmall jobs Wherethe saving cost of moving `the equipment to and from'the job VVis more important than the cost-of the actualpile driving.

lv'The present invention avoids these vdifficulties and involves Ynovel arrangements permitting powerful rapidly operating double acting types o igharnmers andvdiierentialxtypes of hammers to be :constructed and adapted `to be arranged `in assembly .with the upper end of a pile core with the Ventire ram as well as-the greater'part of the remainder of the Yhammer mounted 'within the upper end of the core, thus minimizing "the required head -room for-the core and'hammer assembly, yet permitting full advantage to'vbeV taken of Y theuse 'ci -double acting or differential typesgf hammers. Y y

The ope'ration as Awell as 'the shapeof 4such double acting and differential types of lhammers as heretofore -constructed are such -that Afor-several reasons hereinafter brought'out, they could not in practice lbe mounted to 4operate withinithe conventional typeof 'pile core. Mcre specifically, the j'present invention relates to various features making possible for the frst 'time the assembly and yoperation of these general *types of lfiavrnm-eur's within the -u-pper endgof a `c ore yor the like.

Further objects, features Ivandiiclvantages orf the inventionv hereof `will appear from the Jdetailed description given below, taken in connection with the accompanying drawings iwhich forma part of this specification and illustrate fby way of exampie,preferred embodiments of the invention.

Inthe drawings:

Fig. 1 is an elevational view, partly --section, showing the' upper end portionsof a pile'core with a double tpistonsteam hammer assembled therewith inaccordancewiththe invention;

Eig. 2 is an elevational view of one offthepile cores alone and showing an lupper 4end :portion thereon Aconsiaucted `in vaccordance with the present invention;

Fig. '3 'is lan elevational viewoi a typical metal pile 4shellwhich is to beidrivenby'the assemblypi- Fig. 41 'when positionedrtherewith;

Fig. -4 -an enlarged wertical sectional viewk oi the upper 1portion of the apparatus shown 2in Fig. `1';

f Fig. 5 -is a side -elevationalfview -of the upper portion -of Fig. -4 showing certain-valve operating mechanism `in further'detaih fFig. -6 1`is Va 'sectional view 4taken Vsubstaritial-ly alongline 46 -of Figfll; J

Fig. '7 is a sectional view partly brokenfaway.

taken substantiallyalong-line T.-JI of Figi;

Fig. I8 is a 'vertical sectional view taken substantially-alongline 8-f8 of Fig 4v; and

iFigsQ is a yvertical sectional viewlcorresponding to'Fig. 4,-b1 1t showing analternative Vernbcdiment of the invention.

Referring tothe drawings infurtherdetail'and more yparticularly to `the core Aas tshown-1in r-Fig. 2, it first noted that f-this core may sbe gof .afwell known construction, except that lthe Yupper section I-*ithereof formedion its "upperfendiwith a portion ii6 'of enlarged diameter.` "The upper rim Vof this :latter `lportion iis surrounded by -a-reinforcing ring or the like Il welded thereon and having at oppositely spaced positions two pairs of lugs or the like i8, I8' between which lifting links are received as hereinafter described. With the embodiment of the invention shown in Fig. 9 and as hereinafter described, the upper end of the core does not need to be formed with a portion of enlarged diameter.

Referring now particularly to Figs. 1 and 4, the hammer assembly as shown comprises a body member 2B which includes an upper cylinder 2l of relatively large diameter and a lower cylinder portion 22 of smaller diameter, these cylinder portions respectively containing pistons 2i and 22 of corresponding sizes. These pistons are integral with or rigidly mounted upon a single piston rod 23 having a lower portion 23a terminating in a tapered end 23h tted within a corresponding cavity in the upper end of a ram 24 (Fig. l). This tapered end is locked in position within the ram by a transverse pin as indicated at 25.

` It will be noted that the lower and smaller cylinder portion of the hammer as well .as the ram are received within the working portion of the core l which is of normal diameter, whereas the lower part at least of the larger cylinder portion of the hammer is received in the enlarged portion I6 of the core. As will be noted from the upper portions of Figs. 2 and 3, this enlarged portion is intended in use to be located above the upper end of the pile shell, that is, above the normal working parts of the core.

The lower end ofthe smaller cylinder portion 22 of the hammer (Fig. 4) is closed oir by an annular member 26 which is secured and sealed in place as by the use of a plurality of bolts 2l. The piston rod portion 23a reciprocates within the central aperture and this member 26. A ram guide cylinder 28 is secured as by welding about the lower rim of the member 26 and serves as a cylinder through the lower end of which the ram reciprocates when actuated. This ram guide cylinder also serves in conjunction with the body member to enclose and retain together the hammer and ram assembly when same is withdrawn from the core.

VAt a position just above the ram 24, a thick rubber bumper 30 encircles the piston rod portion 23a. This bumper may be in the form of a split ring of ilexible rubber which may be put into place, or readily removed for replacement when desired, through a hand hole 3| formed in the side wall of the ram guide cylinder (Fig. 1). The purpose of this bumper is to cushion the upper end of the ram with respect to the lower l surface of the member 26 when the hammer is being used in such a way as to drive (i. e. to pull) the core up out of the pile shell, if the core, after driving the shell, should become jammed as it sometimes does against easy upward removal by the crane.

As shown in Fig. 1, the ram 24 is at its position of impact and for reasons hereinafter explained, the impact is preferably applied against a cap block assembly 32 of the type disclosed in U. S. patent to Kinneman No. 2,184,745. 'Ihis type of cap block comprises upper and lower rigid members as at 33, 33 between which are located a stack of so-called Belleville washers or the like 34 to provide an assembly which will cushion the impact to a predetermined degree which does not vary materially even after receiving a large number of impacts. The lower end of this cap block rests upon an anvil block 35` forming a part of the core structure. For the purposes of the particular hammer assembly herein described, an important characteristic of this type of cap block is that neither its normal vertical dimension before impact, nor its compressed vertical dimension upon impact vary materially even after a large number of impacts. For reasons hereinafter further explained, this greatly facilitates the proper actuation and timing of the valves of the double piston type of hammer herein disclosed, whereas if for example a wooden cap block were used which would become more and more compressed after repeated blows, then the position of impact of the ram with respect to the core would change upon successive impacts so as to require readjustment of the valves which control the timing of the impact.

As indicated in the lower portion of Fig. 4, if found desirable, the member 26 on its upper surface may be formed or provided with a drip retaining ring 35 to catch condensate from steam in higher parts of the hammer. This condensate may be drawn away by removing a side plug 31 when necessary and while the hammer is out of the core.

The steam passage and valve arrangements for controlling the operation of the hammer pistons will now be described. As in the case of double piston differential hammers heretofore used, the arrangement of the valves is such that the steam supply is constantly connected to the space between the pistons 2l', 22', whereas pressure is supplied to the space above the large upper piston only during the greater part of the down stroke and momentarily during the final part of the upstroke to cushion the nal upward movement. That is, just before the moment of impact, the steam pressure in the space above the upper piston is released and a passage from this space remains open to exhaust until the upstroke is nearly completed, whereupon pressure is again admitted above the piston 2 I to cushion and stop the upstroke. Admission of the iiuid pressure above the upper piston thereafter is continued and acts with the aid of gravity to force the piston assembly down again, the active and e'ective piston area then being equivalent to the area of piston 22. (That part of the area of piston 2| which is in excess of the area of piston 22 will have the same pressure thereon both above and below and thus will be ineiective in contributing force to the downstroke; and that part of the area of the piston 2i' corresponding to the area of piston 22 will be subject to pressure on the upper side and this will be effective together with gravity in causing the downstroke, since the underside of piston 22 is not under pressure.)

The main control valve may preferably be of the Corliss type mounted on the top of the hammer within an extension portion 23a of the body of the hammer. As shown in Fig. 8, this valve may comprise a cylindrical member 38 formed on its side with a passage 39 adapted either to connect a steam inlet passage 40 with a passage 4l entering the larger cylinder or for connecting the passage 4l with an exhaust passage 42. As shown in Figs. 4 and 5, a cam or lever member 43, is adjustably secured to one end of the valve member 38, this lever member being adapted to be operated by a, reciprocating rod 44 which passes through a suitable stufhng box down into the larger cylinder space 2 I. During the greater part of the upstroke, the valve member 38 will be in a position so that its passage 39, as indicated by dotted lines in Fig. 8, will connect the passage pin 69 or by other suitable means. Normally this buttery valve is positioned as indicated by full lines in Fig. 6 so as to offer no substantial restriction to the passage of steam into and through the valve member 38 to the large cylinder. However, when it is desired to have the hammer impart an upward impact, then the butterfly valve is moved to the angle indicated by dotted lines in Fig. 6, thereby somewhat restricting the admission of pressure. This will not only reduce the cushioning effect at the end of the upstroke to a sufficient degree to permit the bumper to strike an upward blow against the hammer assembly, but also, during the subsequent downstroke of the hammer, the admission of fluid pressure will be so restricted that the hammer will not impart strong downward impacts` As above noted, the cap block 32 against which the ram impact is imparted (lower part of Fig. i) should be of a type which does not progressively change its normal vertical dimensions as the result of repeated impacts. The advantage of a cap block of this type will now be apparent after considering the above description of the control valve and steam passage arrangements. That is, assuming that a cap block were used of a type such, for example, as of wood, which would become pounded successively to smaller and smaller vertical dimensions, then the location with respect to the core at which the impact takes place will move downward somewhat with each succeeding blow. Consequently either the timing of the cut olf of the pressure above the larger piston would have to be changed, or else the maximum possible period of maintenance of such pressure for most effective action of the hammer will be decreased. Any step-by-step shifting of the timing of the valves would, of course, involve complicated and possibly undependable mechanism. Also, if a wooden cap block` is used, there will not only be a variation in the force of successive blows, but also the ram will tend to damage the remainder of the hammer assembly because of over-stroking unless the wooden block is changed at inconveniently frequent intervals. It may further be noted that if the ram were to impart its impact directly to the anvil block or directly to any other solid member, then no cushioning effect would be provided and severe destructive shocks would be imparted to the piston and ram assembly and other parts. But with the type of cap block above disclosed, all such diiliculties are readily avoided.

With all of the embodiments of the invention it will be apparent that an assembly is provided such as to permit the powerful rapid-blow type of double piston differential hammer to be used, and yet used in such a way that only a small part of the height of the hammer and ram assembly protrudes above the core. And by placing the upper larger cylinder of this type of hammer above the working part of the core, this cylinder can readily be made as large as desired and hence in practice there is no denite limit to the weight of the ram which can be used. (The lifting power of the hammer depends upon the pressure against the area of the underside of the large piston minus the area of the small piston.) The weight of the ram may be greatly increased if desired by increasing its length, and yet a hammer with an upper piston sufficiently large to lift such a heavy ram can still be provided and largely contained in the core, since the large cylinder part only of the hammer need be located above the working part of the core where the diameter is limited by the diameter of the pile shell. It, therefore, becomes possible with this invention to use a ram as heavy as desired within reasonable limits and also to increase greatly the number of blows per minute as compared with prior assemblies of single piston hammers within pile cores.

As above stated, with the embodiment of the invention shown in Fig. 9, the core 15 does not have to be provided with an enlargement at its upper end. Instead the flange formation at 'I6 at the lower part of the larger cylinder portion of the hammer may rest directly upon a rubber cushion ring H which in turn rests upon the upper end of the core 15. And with this embodiment the pistons as indicated at '18, 18 for temporarily gripping the core, are located in the lower end portion of the smaller cylindrical part of the hammer, the fluid pressure passage for controlling these pistons being indicated at 19 extending from an intake port within the upper end of the larger cylinder down to an annular passage 8| at the region of the piston 18, 'IB'. The construction and operation of other parts of the embodiment of Fig. 9 will be apparent from the above description of Fig. 4.

It may be noted that temporary gripping means in the form of pistons such as at 60, 60 of Fig. 4 and 18, 18 of Fig. 9 may be used for various types of hammers other than the differential types here disclosed, but which are double acting and which may consequently tend to rise in a core or casing during a part of the cycle of operation, in the absence of such gripping means.

Although certain particular embodiments of the invention are herein disclosed for purposes of explanation, various further modifications thereof, after study of this specication, will be apparent to those skilled in the art to which the invention pertains. 1Reference should accordingly be had to the appended claims in determining the scope of the invention.

What is claimed and desired to be secured by Letters Patent is l. The combination comprising: a tubular pile core; a double piston differential type of uid pressure hammer located in said core; a ram in said core beneath said hammer and connected to the piston rod thereof, the lower and smaller piston of the hammer being contained in a cylinder portion of external dimensions such that same is slidable within the normal working portion of the core, and the upper and larger piston of the hammer being contained in a cylinder portion larger than, and above the normal working portion of the cor'e.

2. The combination comprising: a tubular pile core; a double piston differential type of fluid pressure hammer located in said core; and a ram in said core beneath said hammer and connected to the piston rod thereof, the lower and smaller piston of the hammer being contained in a cylinder portion of external dimensions such that same is slidable within the normal Working portion of the core, and the upper and larger piston of the hammer being contained in a cylinder portion of larger diameter than, and above the normal working portion of the core, said hammer having control valve means for the pistons thereof located upon the upper end of th larger cylinder portion.

3. A double piston differential type of uid pressure hammer and ram assembly adapted for telescopic assembly with tubular pile cores and the like, comprising in combination: relatively large and smaller adjoiningV cylinder portions containing pistons` respectively of corresponding sizes and secured to a common piston rod, the smaller cylinder portion being lowermostl and having a tubular ram guide attachedl tovv and depending-'from-the lower enclthereoi and an elongated ram in'said guide secured at its'- upper end tti-said' piston, said smaller cylinder portion and said ramguide being adapted tobe slidably received within the working part of a pile core.

la The combination comprising: a tubular pile core having an upper end portion of enlarged diameter as compared with the diameter of the normal working portion of the core; a double piston differential type of iluid pressure hammer located in said core; and a ram in said core beneath said hammer and connected to the piston rod thereof, the lower and smaller piston of the hammer being contained in a cylinder portion of external dimensions such that same is slidable within the normal working portion of the core, and the upper and larger piston of the hammer being contained in a larger cylinder portion of external dimensions such that same is at least partially slidable within the enlarged core portion but not into said working portion of the core.

5. A fluid pressure operated hammer adapted for telescopic assembly with a surrounding casing or the like, said hammer having iluid pressure operated means in its side walls for frictionally gripping the interior walls of the casing or the like to prevent movement of the hammer with respect to the latter.

6. A fluid pressure operated hammer adapted for telescopic assembly with a surrounding casing or the like, said hammer having fluid pressure operated piston means in its side wall, movable transversely of the main axis of the hammer to frictionally grip the interior wall of the casing or the like, and conduit means extending from said p-iston means to the same source of fluid pressure as provided to operate the hammer.

7. A double acting fluid pressure operated hammer adapted to be received in a casing or the like, said hammer having fluid pressure operated means thereon for gripping the interior wall of the casing, and connections for bringing the fluid pressure which operates the hammer during a predetermined part of its stroke into communication with said iluid pressure operated means to cause the latter to grip the casing during said part of the stroke.

8. A double acting fluid pressure operated hammer adapted to be received in a casing or the like to be driven by the hammer, said hammer having fluid pressure operated means thereon movable transversely of the axis of the casing for frictionally gripping the interior wall of the casing, and connections for bringing the fluid pressure which operates the hammer into communication with said fluid pressure operating means, said connections including means automatically to release pressure from said fluid pressure operating means at a time close to the moment of impact of the hammer, thereby releasing the gripping action on the casing to permit the casing to be freely driven by the impact.

9. A double piston diierential type of uid pressure operated hammer adapted for telescopic assembly with a surrounding casing or the like, said hammer having uid pressure operated means in its side wall for frictionally gripping the interior wall of the casing or tbe like, and conduit means for bringing said uuid pressure operated meansinto communication with and under the control ofA the samef fluidv pressure as provided inthe larger cylinder of the diiferential hammer.

10. In combination: a fluid pressure' operated hammern of a type having av piston and adapted to strike a downward blowy bythe action of uid pressure above suchY piston and havingv an automatically controlled valvefor releasin'gjsuch 'pressure at a time close tol the momentof impact;` av casing within which such hamm'erjis received, said; hammer having fluid" pressure means thereon foru grippingthe,r interior of; lthe casing; and. connections for bringiifigV saidj' fluid pressure operating means into communication with, and for operation by, said fluid pressure above the piston, to thereby cause said means to grip the casing during the downstroke of the hammer until release of such pressure.

11. The combination comprising: a tubular pile core; and a double piston differential type of fluid pressure hammer, the lower and smaller piston of the hammer being contained in a cylinder portion slidably received within the core, the upper and larger piston of the hammer being contained in a cylinder portion larger than and at least partially located above the normal working portion of the core.

12. The combination comprising: a tubular pile core; a double piston diilerential type of fluid pressure hammer, the lower and smaller piston of the hammer being contained in a cylinder portion slidably received within the core, the upper and larger piston for the hammer being contained in a cylinder portion too large to be received in the core; and a cushioning means interposed between -the upper end of the core and peripheral parts of the latter cylinder portion.

13. In combination: a fluid pressure operated hammer of a type having a piston and piston rod and adapted to strike a downward blow by the action of fluid pressure above such piston and having an automatically controlled valve for releasing such pressure at a predetermined time close to the moment of impact; a ram connected to the lower end of said piston rod; and a cap block beneath such ram adapted to impart blows from the ram to an anvil block, said hammer, ram and cap block being adapted to be received in a tubular casing connected to the anvil block to be driven thereby, said cap block comprising a plurality of superposed members, which are resilient to a predetermined limited degree in the direction of the axis of the ram, and which serve to maintain the cap block normally with a substantially constant vertical dimension prior to each impact.

14. In combination with a tubular pile core: a double piston differential type of ilud pressure hammer at least partially received in such core and connected to the upper end thereof by linkage means, said hammer having automatically controlled valve means and connections for maintaining substantially constant pressure between the pistons and for maintaining pressure above the larger piston during the greater part of the downstroke, and the final part of the upstroke for cushioning purposes; a piston rod connected to the hammer pistons and extending downwardly therefrom; a ram connected to the lower end of said piston rod; a bumper interposed between said ram and the lower part of the body of the hammer; and valve means for limiting the admission of pressure fluid above the larger piston, thereby to limit the cushioning of the upstroke whereby the hammer will strike anupward blow for imparting an upward blow through such linkage means to the core. Y

l5. A double piston diierential type of uid pressure operated hammer having interconnected upper and lower pistons, contained respectively in relatively large and smaller cylinders, and valve means and connections for maintaining substantially a constant pressure between saidpistons and for maintaining pressure above the larger piston during the greater part of its downstroke and the final part of its upstroke for cushioning purposes, said valve means including a push rod extending into the upper cylinder and positioned to be actuated by the larger piston as it approaches the limit of its upstroke to then actuate the valve means to admit pressure above the larger piston, and a fluid pressure operated means connected to receive operating uid pressure from the space between the pistons at a time near the end of the downstroke for restoring said valve means 10 to closed position.

EDWARD A. SMITH.

No references cited.

Images