US2885862A - Power hammer construction - Google Patents

Description

United States Patent OfiFice 2,885,862 POWER HAMlVIER CONSTRUCTION Edward A. Smith, Chatham, N.J., assignor to Raymond International Inc., New York, N.Y., a corporation of New Jersey Application November 1, 1955, Serial No. 544,225

2 Claims. (Cl. 61-76) This invention relates to fluid pressure operated power hammer constructions of types particularly adapted, for example among other. uses, for the driving of piles and the like. More specifically the invention concerns hammers of the above-indicated class and of the type having a base, and a cylinder and piston assembly mounted at a predetermined distance above such base and connected thereto by vertical columns, along which columns a heavy ram assembly isadapted to be reciprocated vertically by the cylinder and piston means. Such ram at its lower side is arranged to strike against so-called cap block means at or within the hammer base, or against whatever other desired element or elements the hammer is adapted to apply impacts.

Hammers of this general type have been in extensive usefor many years, despite the fact that samehave involved some serious difliculties so far as concerns the problems of rapidly assembling the various parts thereof with respect to the columns and by means which will permit the several units of the assembly quickly to 'be taken apart for repair and replacementand still .having columns of such form as to be durable. Frequently, also, the particular columns, hammer base and cylinder assemblies have had to be adjusted and fitted with respect to each other for each particular hammer, so that the main units of such hammer were not quickly useable interchangeably.

f In hammers of the type above referred to, ordinarily four of the columns are provided for holding the base and the cylinder castings in thedesired spaced relation to each other and to provide guides for the ram. Initially years ago it was the practice to form such columns with shoulders where they engaged near their upper and lower ends the hammer base and the cylinder assembly respectively, for holding the latter in predetermined spaced relation. And for retaining the ends of such columns in place, transverse keys were inserted through apertures in the columns. Since the rams of such hammers weigh many thousands of pounds and apply correspondingly heavy impacts, it will be apparent that the whole hammer assembly will be subjected to repeated heavy shocks throughout the times during which the hammer is in use. Thus in order uniformly to distribute among the four columns such powerful forces as were applied thereto, it was necessary that same be all of effectively uniform length and so keyed or retained in position that the forces on .the shoulders of the severalcolumns would be uniform and that the columns be strong enough to resist stretching or breaking at the points where shoulders or other changes of diameter occurred thereon and also at the points where slots were provided for the keys. It was found, however, that such shoulders were prone to be starting points for breakage of the columns and that there was a tendency of the key means for holding the column ends in place to become dislodged or displaced far enough to loosen the assembly and prevent uniform distribution of the loads between the columns, further promoting breakage thereof at the an attempt to avoid such shoulder formations on the columns with their related difliculties, it has for many years been the practice with many hammers to form the upper and lower ends of the columns respectively with upwardly and downwardly directed tapered portions closely fitting correspondingly tapered sockets in the cylinder member and in the base member, key means or the like also being generally provided to insure that these tapered portions would be held tightly in their sockets. While this construction avoided the shoulders on the col umns and the problems of breakage of the columns at said shoulders, and otherwise provided a generally dependable construction, yet in order uniformly to distribute the loads among the four columns, it was necessary very accurately to fit the tapered portions with respect to the tapered sockets in the cylinder piece and base member. But this task, whenever new parts had to be installed because of wear or breakage, generally involved sending the whole hammer assembly to a properly equipped factory, and even there the fitting operations might require as many as tentdays of work by experts. And the necessity of shipping. heavy hammer assemblies from very remote points where pile driving work is often done, back to a factory for such replacements and fitting of new parts, has long been a serious cost factor in the maintenance of pile driving hammers with the above-described types of shoulders or slots thereon; In

column means.

i The present invention provides a novel and relatively simple form of column construction and assembly of the class above referred to, which avoids the above-noted difiiculties and makes it possible readily to take apart and reassemble such hammer constructions whenever necessary in the field, without incurring the expense of returning same" to a factory and without requiring the services of specially trained experts. At the same time the invention makes possible the use interchangeably of various different hammer bases, cylinder assemblies, ram assemblies and columns without special fitting and adjustment thereof.

In accordance with the invention, the column means are provided in the form of through bolts positioned in apertureswhich extend vertically through the base, the ram, thecylinder piece and the cylinder head. Such bolts are each surrounded by tubes, the lower ends of which engage the upper surface of the hammer base and the upper ends of which engage the lower surface of the cylinder-member so that such tubes form spacers for retaining the base and cylinder at the desired predetermined distance apart when the bolts are tightened in place, such tubes also ,at the same time providing guides for the ram in a form which is easily replaceable if and when same become worn.

Another long-standing difficulty with differential type hammers of. the class and types above referred to has involved the provision of a reliable and economically operable valve arrangement for controlling the admission and discharge of fluid pressure from the cylinders. With such types of hammers it has been the common practice to mount a valve-operating slide bar on the hammer ram to extend above such ram for actuating the valve mechanismmounted on the cylinder. And in order that such slide bar, when in its uppermost position, need not extend up higher than the upper portion of the cylinder head, forthis reason among others, it has been the common practice to mount the valve adjacent the lower portion of the cylinder piece. However, since the intake and'exhaust ports to the cylinder have to be located at the upper end of the cylinder, the positioning of the valve nearthe lower end of the cylinder involves wastage of a substantial volume of the pressure fluid with each stroke of the hammer. That is, there had to be provided a fairly voluminousf'ree passage from the valve adjacent Patented May 12, 1959 the lower end of the cylinder extending up to the intake port at the top of the cylinder in the cylinder head piece, so that each time the valve acted to shut ofi the flow of pressure fluid, the contents of this passage would be discharged and lost along with the fluid exhausted from the cylinder. It should be noted that in differential type hammers, the pressure conditions are such that, if the fluid pressure on its way into the upper end of the cylinder is throttled by reason, for example, of a small fluid passage, even by a rather small percentage, then the fluid pressure portion of the driving force of the hammer will be diminished by a much larger percentage. Thus if the valve is located down adjacent the lower portion of the cylinder, while this may be convenient from a mechanical standpoint, it will involve a very serious decrease of the hammer force unless the passage from the valve to the top of the cylinder is quite voluminous and thus wasteful of pressure fluid.

However, the present invention provides a novel, improved and dependable valve operating mechanism which is largely located adjacent the lower end of the cylinder, but which is constructed and adapted to actuate a valve located up in the cylinder headpiece so that the abovenoted waste of fluid under pressure is avoided. At the same time, the important cam pieces for accurately operating the valve with proper timing, are located adjacent the lower portion of the cylinder where rugged, dependable slide bar means is made available to actuate same dependably in accordance w'th movements of the adjacent ram. Also at the same time the novel valve operating mechanism is such that the cylinder assembly with the valve operating mechanism thereon, can be quickly removed as a unit and replaced by another, without any serious or troublesome steps being necessary to retime the valve, this being made possible in part by reason of the fact that the new cylinder assembly will come accurately into a predetermined position by reason of the improved columns arrangement above referred to.

Further objects, features and advantages of the invention hereof will appear from the detailed description given below in conjunction with the accompanying drawings which form a part of this specification and illustrate by way of example, a preferred example of the invention.

In the drawings:

Fig. l is a view largely in vertical section showing various portions of a preferred form of hammer such as used for pile driving purposes and embodying the invention;

Fig. 2 is a side elevation of the same hammer assembly as viewed in a direction at right angles to the view of Fig. 1, portions here also being shown in vertical section;

Fig. 3 is a side elevational view like that of Fig. 2, but greatly enlarged and with various portions broken away;

Fig. 4 is another vertical sectional view of the same embodiment of the invention taken at right angles to the view of Fig. 3, on a similarly enlarged scale and certain parts being broken away; and

Fig. 5 is a horizontal sectional view taken substantially along line 5-5 of Fig. 4.

I Referring now to Figs. 1 and 2 of the drawings in further detail, the principal portions of the hammer there shown may comprise a base 10, a cylinder and piston assembly 11 with a cylinder head assembly 11a secured on the upper end thereof. The cylinder and head assembly are supported and retained in' spaced relation to the base by means of column assemblies as indicated at 12. Ordinarily, as above stated, there will be four of such column assemblies, the axes of which will be located at the corners of a rectangle, although for clearness only two of the column assemblies are indicated in Fig. 2. A ram assembly 13 is mounted to be reciprocated vertically along the column means by reason of connection thereto of a piston rod 14, which in turn is connected to the differential pistons 15 and 16 within the cylinder piece.

The base 10 may be of a well known form adapted to contain a cap block assembly 17, such for example as is disclosed in the co-pending application of Edward A. Smith, on which US. patent No. 2,723,532 was granted on November 15, 1955, such cap block assembly acting to apply impacts for example to a so-called follower 18 or other member which is to receive the impacts. Buffer means as at 19 of suitable known form may be provided on the upper surface of the base to cushion impacts of the ram in cases when the ram movement is not stopped by engagement with the cap block assembly.

The ram 13 may be of a suitable known type, the details of construction of which, except as hereinafter noted, form no part of the present invention. It will be noted, however, that in typical instances where the present invention has been successfully used, such rams have a weight of some 15,000 pounds, which gives an indication of the rugged and dependable requirements for all parts of such hammers if they are to be kept in use for substantial periods without breakage.

The differential cylinder and piston assembly and the cylinder head 11, 11a, 15, 16 etc., may also be of conventional known types of construction and therefore the details of which need not here be described, except for the features hereinafter noted with respect to the column means and the valve operating mechanism. The valve per se, which is indicated at 20 and which controls the intake and exhaust of pressure fluid to the cylinder, may be of the Corliss type and the particular arrangement of the passages therein and associated therewith may be de-' signed in accord with known practices, one example of such a valve mounted on a cylinder head being disclosed in the US. patent to Edward A. Smith, No. 2,598,455, granted May 27, 1952.

Referring further to Fig. 2, each of the column means 12 may comprise in effect a through bolt as at 21, formed at its lower end with a tapered headpiece 22 received within a correspondingly tapered socket formed in the bottom portion of the base of the hammer. It will be noted that each such bolt extends directly up through a corresponding aperture in the hammer base, the lower and upper portions of such apertures being bored to closely fit the bolt, whereas in the mid-portion of the base, the aperture may be cast of a diameter large enough to have clearance with respect to the bolt as indicated at 23. A tubular sleeve as at 24 surrounds each such bolt within the space between the upper surface of the ham mer base and the lower surface of the cylinder piece 11, so that such sleeves, made of accurately predetermined length, can be slid into place on each bolt to provide accurate spacers between the hammer base and cylinder member. The hammer ram 13, as will be noted, is also provided with apertures within which the sleeves 24 are slidably received, such apertures as at 25 and 26 within the lower and upper portions of the ram, being bored accurately but slidably to fit the sleeves, whereas the remaining portion of the apertures in the ram may be cast of a larger diameter as at 27 to receive the sleeves with suitable clearance.

The cylinder member and the cylinder head also are formed with aligned apertures for each bolt formed similarly to those in the ram and hammer base and each bolt or column member is threaded at its upper end to receive nuts as at 28, which when tightened down, act in cooperation with the bolts to pull the base upwardly against the lower ends of the sleeves 24, while forcing the cyclinder member 11 down against the upper ends of the sleeves 24, thus holding the entire hammer in assembled condition.

In assembling the main parts of the hammer, the base 10 is first slipped down over the bolts 21 until the tapered bolt head portions 22 are firmly engaged in the conical sockets therefor; then the tubular sleeves 24 are slipped down in place on the bolts 21; then the ram is slid down into place on the column means; and the cylinder and cylinder head assembly finally is slid down into place onto flleupper end portions of the bolts, whereupon the nuts 28are firmly screwed in place. In order quickly to take apart the assembly, corresponding steps may be taken in the reverse order, as will be readily understood.

The use of tapered head portions as at 22 for the lower ends of the bolts, avoids any abrupt changes in the diameter of these members at any point and consequent liability of-breakage at such points. Yet, since the bolts may be drawn up firmly with uniform tension into place within their tapered sockets by means of the threaded nuts 28, there is no necessity of individually fitting each tapered bolt portion with respect to its particular tapered socket as was the case in prior constructions above referred to wherein the predetermined accuracy of such fitting of tapered parts had to be depended upon to insure that the loads would be uniformly distributed among the several column means. With the present invention, the tubular sleeves 24 may all be easily made of the same accurately predetermined length and even though such sleeves become compressed somewhat in length in use while the bolts :will become elongated by stretching, yet all the column means will carry exactly the same load if the nuts 28 are all tightened to a uniform degree. Thus the main units of the hammer may be all assembled to- ,gether very quickly, and if any of the tubular sleeves 24 become worn and need replacing, this can readily be done upon taking off the nuts 28 and separating the hammer parts.

Reference will now be had particularly to Figs. 3 to in describing the valve operating mechanism. A slide bar 30 is mounted in upstanding position on the ram 13, the lower end of this bar being secured in fixed position within a socket 31 in the ram and locked by the use of a transverse key member as at 32. The upper end portion of this side bar has afiixed thereon a downwardly directed cam portion 33 arranged alongside and adjacent an upwardly directed cam portion 34. These cam portions respectively are adapted, upon movement of the ram, to engage rockable trip members 35 and 36 which are fixed upon a small rockable shaft 37, to which is also fixed a lever 38. The shaft 37, as shown in Fig. 5, is mounted in bearings formed in a U-shaped bracket 40, suitably bolted to the lower portion of the cylinder member. The outer end of lever 38 is pivotally and detachably connected to a valve-operating rod 41, the upper end of which is also pivotally and detachably connected to a valve-operating lever 42, which is fixed upon and rocks with a shaft 43 which is connected to and rotates 'with the valve piece 20. Shaft 43 may be mounted in a suitable bracket 44 bolted to the side of the cylinder head member 12.

Thus when the ram 13 moves downwardly, cam portion 33 will engage trip member 35, thereby tilting the lever 38 upwardly, and thus through the medium of members 41 and 42 will act to turn the valve piece clockwise as viewed in Fig. 3. Similarly, when the ram is on its upstroke, cam portion 34 will engage trip member 36, thereby causing the valve piece to be turned counterclocktfise.

When the hammer is to be taken apart and upon unscrewing the nuts 28, the cylinder and cylinder head assembly may he slid up and lifted off the column means 12 without requiring disassembly of any of the valve operating mechanism. Similarly, when the parts are reassembled, the cylinder and cylinder head assembly may be slid down into position and the valve operating trip members 35, 36 will assume the position shown in Fig. 3 with respect to the slide bar 30 and the cam portions thereon, ready for operation, usually without further adjustment, provided tubular members 24 of the column means are always selected of an accurately predetermined length for insuring proper spacing of the hammer base of the cylinder assembly,

6 and cylinder with respect to the position of travel ofrthe ram.

Since the ram is subject to heavy shocks in rapid succession, any valve-operating slide bar means carried thereby is subject to such shocks and the liability of destructive vibration, with consequent uneven wearing or injury of any cam parts thereon. Since the cam mechanism. 33 to .36 inclusive is all located adjacent the lower end of the cylinder member, the slide bar 30 may be kept relatively short in length and free of such vibration troubles. Yet with the cam mechanism in this position, same can still .readily be connected by the simple means comprising the valve rod 41, to the valve located up in the cylinder head, so that the above-mentioned wastage of fluid pressure is avoided, that is, the wastage which would occur if the valve were located down by the cam-operating mechanism therefor. Also, with such cam mechanism at this lower position, it is unnecessary that the slide bar at any time extend up far enough to interfere with, or strike, any parts located adjacent or above the upper portion of the hammer.

As to the details of construction of the various hammer parts other than those above specifically described, well known practices for the construction of hammers of this general class may be followed.

Although a preferred embodiment of the invention is herein disclosed for purposes of explanation, various other modifications thereof, after study of this specification, will be apparent to those skilled in the art to which the invention pertains. Reference 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:

1. In a fluid pressure operated power harmner construction of a type having a cylinder and piston assembly mounted in a position spaced above a hammer base and a ram assembly reciprocable by the piston in the space between said base and said cylinder assembly, a plurality of column means for interconnecting said cylinder assembly and base and for retaining same in a predetermined spaced relation, each of said column means comprising a through bolt, said base, ram and cylinder assemblies each being formed with apertures in the walls thereof and through which the bolts extend continuously from the lower portion of the base to the upper portion and tubular sleeves respectively of predetermined length embracing each of such through bolts, the lower ends of such sleeves abutting the base and the upper ends thereof abutting the underside of the cylinder assembly, said sleeves respectively extending through the apertures in the ram and comprising guides on which the ram vertically reciprocates.

2. In a fluid pressure operated power hammer construction of a type having a differential cylinder and piston assembly mounted in a position spaced above a hammer base and a ram assembly reciprocable by the piston in the space between said base and said cylinder assembly, a plurality of column means for interconnecting said cylinder assembly and base and for retaining same in a predetermined spaced relation, each of said column means comprising a through bolt, said base, ram and cylinder assemblies each being formed with apertures through which the bolts extend, means on such bolts forming guides on which the ram reciprocates and which also act as spacers between the base and cylinder assembly, a valve actuated slide bar fixed with respect to the ram and extending upwardly therefrom, a rockable valve mounted in the cylinder headpiece for controlling the intake and exhaust of pressure fluid for the cylinder, rockable trip members mounted on the lower portion of the cylinder assembly, linkage connecting said trip members and the valve, and cam means on said slide bar for actuating said trip members respectively thereby to cause turning of the valve to admit an exhaust pressure fluid in timed relation to the reciprocation of the ram, said ,cylinder andpiston assembly being slidably removable upwardly with respect to said column means and slide bar, while said valve, trip members and said linkage all remain in assembled condition on the cylinder assembly.

References Cited in the file of this patent UNITED STATES PATENTS 498,493 Sergeant May 30, 1893 647,274 Moran et a1. Apr. 10, 1900 Germany July 18, 191 0

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