US2004180A - Power hammer - Google Patents

Description

POWER HAMMER Filed Feb. 4, 1931 4 Sheets-Sheet 1 //v VEN 70F? June 11, 1935. c. v. ADAMS 1 ,00 80 POWER HAMMER 1 Filed Feb. 4; 1931 4 Sheets-Sheet 2 C. V. ADAMS POWER HAMMER June 11, 1935.1

Filed Feb. 4, 1931 4 Sheets-Sheet. 5

B E RE Filed Feb. 4, 1931 4 Sheets-Sheet 4 Patented June 11, 1935 PATENT \QTFPFEICEE rPoWEnHAMm-R "'CampbellV. Adams, Chicagnflll.

Anplication rEebruanyi'zi,

1931, Serial No. 513,269

Myinvention relates broadlyzto powerrhammers and morezparticularly to 'theltype of LIJOWGl'lhflIIlmers known as pile hammers, .in which :a .:ram is automatically operated. :by motive 'fluidl'supp1ied=to=the.cylinder:to impart motion to theeram. Although' I shall :refer :throughout thepresent disclosure to .this :particular adaptation :of imyrinvention, :it is to-be understood ithatrmy invention is not :to-ibe limited ftOiSllCh use :solely, but may be .used broadly in the construction of power hammers.

Two different types :of power ihammers have heretofore ibeen provided. :Of these types, Lthe single-acting hammer utilizes ithel-motive fluid-on the "up stroke of the piston toraise the :ram :and

thereafter .to exhaust :the motive 'fluid zto :permit the piston and the ram to fall -by gravity and strike a blow dueto acceleration ofigravity only. On :the other hand, rdoubleeacting "hammers not only utilize :the pressure of themotive fluid against the piston .to raise the ram, butalsoito accelerate the down stroke of :the ram. Several-different principles of fluid distribution have heretofore been :used in the operation of double-acting hams mers.

may be first admitted to the cylinder beneath the piston to raise the :ram and 'then iused -expansively at both ends of the cylinder during the down stroke before being exhausted from the upper end of the cylinder only. A still ifurther l and third form .of motive fluid distribution 'is where a constant supply ofiluid at a uniform pressure is maintained in 1 the lower end of the cylinder below the piston, while forthe down stroke a quantity of fluid is admitted fromithe 1 lower end to the upper end of the cylinder :and,

ill)? because of the limitations of design, must :of necessity be used expansivelyrto complete the stroke before being exhaustedto atmosphere; My in-,

vention belongs largely to this latter type of? double-acting hammers, but :differs essentially therefrom by the manner which the'rfluidisdistributed so that the advantages inherent the construction andoperationof i bothlsingle and double-acting power hammers, as :wellqas man-y other teatures, may be combined in a single structure. i

The principle' of operation of a single-acting hammer advantageously permitsathe use of .a

heavy ram lbut inherently limits the rapidity .of succession of blows :of rthe ram, while in the double-acting type rapidityiof succession :of blows by the ram is advantageouslyobtainecl,zbuttthe principle; or: operation-inherentlyrequiresrallighter ram ito Ebesused. 1n lhammers :of :either :of these types ihaving equal striking energy, the .number of Fblows struck within-1a given 3 time :mustibe i definitely'fixed rbyzthe :ratio o'fvram weight to :dead weight. Eurthermore, the established ratio between ram weight and dead weight also determines the area of *piston available for lifting the ram. :Also, due to' the =method of fluid:distribution in certain of these-priortypesof power hammers, -and particularly in the-'double-acting com pound typesy leakage .of fluicl past %the valve or piston. has quite ffrequently prevented the hammer 'from startingiriwh'en th'e motive fluid is admitted and ofttimes has caused the hammer to start 1 operating b'ut without delivering any blows. Many other disadvantagesand=detrimental efiects in the r operation of powerihammers caused chiefly by the manner (if-"fluiddist'ribution have been experienced heretofore andhave caused considerable trouble in their practical use.

5 'Myinvention is designed with a view of obviating such undesirable limiting factors and detrimental efiects and is a radical departure from former types in that the'motive fluid is:distributed to the cylinder in a manner obtaining exceptionally eflicient operation. Primarily, the

object of the invention resides in providing a source of fluid supply for maintaining a substantially-constant fluid pressure =in the lower end of the cylinderbelowthe piston during the oporation of the hammer whereby the fluid "will act to raise the'ram andthenat the proper time during the upward movement-of the piston fluid will be supplied, at the-same pressure, to the upper end of the cylinder above'said piston, either by a communicating passage controlled by-a valve or indirectlybya source of 'fiuidsupply controlled by a'vailve, to chec'kthi-s upward movement or the ram and to "remain in the upper end of the cylinder at a constant pressure during the down stroke of the ram, being exhausted at the end of this -stroke 'by a controlled "valve, so that during this down stroke of the ram, flu'id of-the same pressure will be prov ided to act simultaneously upon both sides of the piston. Another object-of the invention is to provide a simple means of controlling the distribution of the motive fluid in the manner aforesaid, comprising essentially any formor type of valve, capable of operation in the usual way, that is to say, by the movement of the piston, piston rod or :extension thereof, or ram, witha simple form of cam arm arrangement, or the like, for actuating the valve as motion is imparted to the piston and ram by the motive fluid. A further object of the invention resides in the eflicient construction and arrangement of the cylinder housing and associated parts employed to protect the moving parts, such as the ram and valve mechanism, the cylinder being also enclosed to insulate it from loss of heat and to provide a cool exterior surface, when employing a heated fluid and also to make the hammer adaptable for sub-aqueous work. The housing may comprise several parts so connected together that either part may be removed to obtain access to the valve, ram or cylinder, without removing or even disturbing the mounting of the cylinder within .thehousing. The following advantages, as well as others, are the result of my invention:

(a) Employment of a heavy ram of the singleacting type capable of operating withthe same rapid succession of blowsas does a ram of the double-acting type.

.(b) The provision of a ram exceedingly heavy in proportion'to dead weight for a selected driving energy and velocity'of impact, thereby producing a more e'fiicient-blow, byreasoncof less loss of energy during impact, than is possible in other hammers of this type having the same total weight;

Increasing the numberof blows within a given time and with the same fluid pressure for a given ratio of ram weight to dead weight.

((1) Greater economy in fluid consumption per unit of energy delivered bythe blow.

(6) Causing the wire-drawing or throttling of the elastic fluid during opening and closing movement of the valve to occur at a period in either stroke where the detrimental eflects thereof are of no material consequence.

(f) Preventingthe leakage of fluid pastthe valve or piston from hindering the starting operation or from initiating the starting stroke Without delivering a blow.

(y) By altering the. stroke'of the ram, the

dead weight may bevaried to any desired figure while the fluidpressure, weight of ram, striking energy and velocity of impact stant.

(h) Providing greater latitude in the designl of the hammer to meet.;specified conditions by increasing or decreasing the stroke without requiring a corresponding change of the number of blows struck per minute In order to apprise those skilled now describe a preferred embodiment thereof taken in connection with the drawings which form a part hereof. 1

In thedrawings: Q t

Figure 1 is a side view partly in elevation and partly in section, with a portion of the housing removed, of a power hammer embodying my invention; l I

Fig. 2 is a similar view, but showing a portion of the operating elements of the power hammer in section;

Fig. 3 is a horizontalsectional view taken on line 33 of Fig. 1; I

Fig. 4 is'a horizontal view looking down upon the power hammer, with the cylinder head removed, one-half of the view-being in elevation and the other half of the view being in section, to illustrate the manner of operating the valve actuating arms'andof supporting the cylinder within thehousing;

ma be kept conin the art how. to practice and construct my invention, I shall Figs. 5 to 8, inclusive, diagrammatically illustrate the different positions of the valve and slide bar operating the tripping arms, for a complete cyclic movement of the piston and ram; and

Fi 9 is a view similar to Fig. 2, showing the cylinder, ram, valve actuating arms, cam and slide bar in elevation.

The power hammer disclosed herein is adapted to be operated by a motive fluid such as steam or compressed air, and is designed principally as a power pile driver, but it is equally applicable-for analogous purposes, as, for example, wherever a percussive blow is used, such as in rock drilling, riveting machines, concrete breaking or tamping and the like.

The power hammer comprises a suitable housing 4' providedwith opposed guideways 2 in which guides of the usual supporting frame (not shown) are arranged to allow vertical movement of the hammer. Sheaves 33 may be arranged upon a cylinder head 4 to receive cables or like flexible members controlling the vertical movement of the hammerwithin the frame.

Cylinder block 5 is attached to cylinder head 4. A piston 6 having a ram 7 attached at its lower end is adapted to operate in cylinder 5. The lowerend of cylinder 5 is reduced in diameter at 8 to provide an auxiliary chamber 9 receiving an auxiliary piston II! which forms a seal at the lowerend of cylinder. 5. The usual piston rings Il may be employed to assure a tight seal.

Motive fluid for operating the power hammer may be supplied by means of an inlet pipe connection 12, shown in Fig. 4, which communicates with a horizontal passage. I 3. Passage I3 communicates in turn with an annular chamber l4 disposed in cylinder 5 below piston 6 and directly communicating with the cylinder below the piston at [5. Enlargement [6 formed on cylinder 5 provides a valve chamber 11 opening into chamber M at one side. Although I have shown a specificform of valve l8 arranged for actuation in valve chamber I1, it will be specifically understood that the fluid distribution may be accomplished by a valve of any type and location. A rock pin l9, suitably mounted in fluid-tight relation in end heads 25 of enlargement 86, carries an admission trip arm and an exhaust trip arm 2|, formed on an enlarged boss 22, mounted exteriorly of enlargement l6, and also carries valve I8 in valve chamber l1. Valve it controls the admission and exhaust of motive fluid of two passages; One of these passages, passage 23, is vertically arranged and formed in the wall of cylinder 5 to provide controlled communication between valve chamber ill and the cylinder above piston 6. The other passage 24 acts as an exhaust for the motove fluid thus supplied to the cylinder above. the piston.

Timed movement of valve It, by means of a slide bar 26 operating trip arms 23 and 2 l, controls the distribution of the motive fluid to the upper cylinder only, so that during the entire cyclic movement of piston 6 fluid will be supplied at full pressure below the piston, and will be supplied at the same or full pressure above the piston during the cushioning period of up stroke and accelerating period of the down stroke. As piston 6 reaches its position of impact, the motive fluid in the cylinder above the piston is exhausted to atmosphere, or otherwise, through passages 23 and 24. Fluid will again be admitted to the cylinder above the piston appreciably before the end of the upstroke. The purpose of admitting it at this period in the operation is to allow it to act as a cushion for the ascendingpiston,'ithe motive fluid thereafter remaining the chamber above the piston during the'down'stroke. Accordingly, the power hammer disclosed herein is adapted to have motive fluid of substantiallyfthe same and constant pressure acting'on'both'sidesof the piston during the down'stroke. I find, therefore, that ram it may be made exceedingly "heavy in'proportion to dead weight for a selected driving energy and velocity of impactit being understood thatdead weight comprisesall parts of thehammer serving to resist the net upward reaction of the fluid against the cylinder head "4. Not only may'the ram be made exceptionally heavy in' proportion to dead weight, which is one of the advantages of a single-acting hammer, buta more rapid succession of blows may beobtained,*wh1'chis one of the advantages of a hammer of the double-- actingtype.

The manner in which valve i=8 provides for this mode of fluiddistribut-ion will be clearly understood by referring toFi'gs. 5 to 8, inclusive.

Fig. 5 illustrates the position of valve {lBatithe moment of impact. I V v Assume now that piston 6 is at the position of the beginning of release, as shown Fig. 8 and is approaching the position as shown in Fig. 5 which is the position of impact. and that it will continue on "to the position of drift as shown in Fig. 9; Cam 26' o-nslide'bar 26 engages exhaust trip-arm 2'! to revolve valve l8 clockwise to uncover passage 23, and thereby to place it in commun'ica tlon with exhaustpassage 24. The motive-fluid is then exhausted toa'tmosphere.

Assume piston 6 is moving upwardly "as shown in Fig; 6, oam 2- 6 on slide bar 26 functions to operate admission trip arm 2ll to rotatevalve I 8 counterclockwise whereby to close oil passage 23 from communication with exhaust 24, and to place passage 23 in communication with valve chamber ll. The particular structure shown places chamber I! under f-ull fluid pressure at all times. Motive fluid is accordingly supplied to the upper part of cylinder '5 above piston 6 at full and constant pressure prior to the completion of the up stroke'of the piston so that acushion is providedquicklyto retard and to check this upward movement. Continued "admission of motive fluid above the piston at the same and constant pressure asexists below the piston allows the piston to descend by gravity and to be further accelerated injits ,descent'by the unbalanced pressure existingabove the piston until the piston reaches its position "of impactwhereupon release.

of the motive fluidabo-ve the piston is effected.

6am 26' on slide bar j2'oimoves exhaust trip arm 21, as shown in Fig. 8, to rotateyalve 1 8 clockwise to the position shown in Fig. 5, which, of course, exhausts the motive fluid above the piston to the atmosphere. 7 ,It will be notedthat the woenmwmg or throttling of the elastic fluid by valve "l8 during any period either in the up or down strokes "does not seriously influence the eflici'ency or" the hammer, this being the result of the valve 1 8 opening and closing at periods either in the up and down strokes, where detrimental effects 'of this sort are of no material consequence; I i

The power hammer herein described may be constructed with its moving parts, such as ram B and valve operating mechanism 20; 2-! and 26, ex

der when usingaheatedfluid, thereby presenting a 0001 exterior surface to the touch and in addition reducing condensation in the cylinder by keeping the cylinder walls warm.

l r In order to providerelatively-quick access to and ram to remain mounted in housing i when possible. To accomplish this end, I provide diametrically opposed flanges 35 on cylinder 5,-

which flanges 3,6 are adapted to be bolted to the opposed flanges 32 0f housing part 30 by means of cap screws 31, as shown in Fig. 4. Flanges 3'6 are adapted to fit snugly between flanges 32 and 33 as theresult of laterally extending shoulders 33 formed on opposite sides of flangestfi, thcse' shoulders providing a seat against which the flanges 32 and 33 may snugly fit. A connecting web 39 carriesflanges .36 on cylinder '5. However, at the reduced lower end 8 of the cylinder, this web is reinforced by horizontal enlargements 49.. 'Cap screwed! do not pass through flanges 33. These cap screws 31 can. only be removed after housing cover 3! hasbeen removed. I

If it is desirable to obtain access to the cylinder, 7

ram or valve parts forthepurposes of repair or the like, cap screws i3] need not be-removed upon removal of housing cover 13!. It willbe noted in Figs. 1, 3 and 4 that directly below flanges 36 a ram guide is provided to guide ram 1' in its up and down movements. A guideway 43 is formed'on oppositexsides of ram 1,- as shown in Fig. 3, to receive guides 42. Guides "42 are provided with outwardly extending flanges 44, which arefadapted to .be clamped between flanges 232 and 33 of housing parts Y30 and 3!. Cap screws 45 function to secure guides 42 inposition'. Housing cover 31 may be also removed without remov ing cap screws '45 or disturbing the mounting of ram 1 within the housing Slide bar 26 ismounted upon ram 1. A portion of the ram at its upper endis' cut away at 11, as indicated in Figs. 1, 3 and 10, and pocket :48 is provided to receive'a head 49 carried by slide bar 2'6. Head 49 is clamped in position in pocket 48 by means of cover plates 51 removably secured in position by means of bolts 52. The slide bar 2 6 will thus move with ram 'Tin its up and down strokes, in order that its cams" 26f will operate the trip arms .20 and. .21.

Although piston rod .53 may beof thesame diameter as the auxiliary packing piston I0, I have shown it of smaller diameter and extending downwardly toconnect with ram 1 by means of a split bushing 54. A spherical head 55 is formed on the lower end of piston rod 53 'so that the'upper face 56 of this head may bear against the lower end of splitbushing 54, as shown in Fig. 2. The upper end of "this "bushing. 54'may be suitably bolted at 51 to ram 1.

Any suitable form of construction at'the lower endof the housing maybe provided toaccommodate the pile. There has-been shown, however, a dolly plate BU-carriedby .a retainer 61' suitably attached-to the lower end of housing I by means of the same bolts 10 asusecureinterposed seat 62. An impact plate 63 is disposed between the seat and the top of dolly plate 60.

Cylinder head 4 may be secured to the top of cylinder 5 in any suitable way. It will be noted in Fig. 4 that inwardly extending flanges 65 are formed at the upper end of housing parts and 3|, but these flanges are so formed as to provide spaces 66 through which inlet pipe l2 and exhaust pipe 61 are carried.

It will be understood that various details of construction of the housing may be changed without departing from the scope of the invention.

It is not essential that the motive fluid be supplied to the cylinder above the piston from the same source supplying the cylinder below the piston. An exceedingly simple design may be obtained where the source of supply is the same, but the same advantageous results flowing from this form of fluid distribution may be had if separate sources are provided. It has been found that the inherent characteristics of the device disclosed resulting from this form of fluid distribution permit a wider latitude. in the design of a power hammer to meet specified conditions. For instance, by altering the stroke, the dead weight may be reduced or increased and the fluid pressure, weight of ram, striking energy and velocity of impact may be kept constant. The number of blows struck per minute may also be kept practically constant if desired, as'the stroke is varied,

by properly proportioning the design of the cylinder. Not only may be above advantages as well as many others be obtained, but greater economy in fluid consumption per unit of energy delivered by the blow is possible, due primarily to avoidance of exhausting fluid from large clearance space beneath piston 6, and to the lessened initial condensation occurring in the cylinder, as the hot fluid entering the upper end of the cylinder on down stroke comes only in contact with surfaces previously heated by fluid underneath the piston.

Without further elaboration, the foregoing will so fully explain the gist of my invention, that others may, by applying current knowledge, readily adopt the same for use under varying conditions of service, without eliminating certain features, which may properly be said to constitute the essential items ofnovelty involved, which items are intended to be defined and secured to me by the following claims.

I claim:

1. In a pile driving hammer, a cylinder, a piston operating in said cylinder, a ram driven by said piston, and valve means for supplying mo- .tive fluid at uniform pressure to said cylinder below said piston whereby the fluid will act to raise said ram and then at the proper time during the upward movement will be supplied to and remain in said cylinder above said piston substantially at the same and uniform pressure to cushion the upward movement and to assist in accelerating the descent of said ram said valve means releasing the fluid above said piston after said ram has travelled downwardly to the position of impact, maintaining the fluid pressure constant against said piston until said point of impact securing a rapid succession of strokes combined with a heavy ram weight for the total weight and striking energy employed.

2. In a pile driving hammer, a cylinder, a pis- 7 ton operating in said cylinder, a ram driven by said piston, and valve means for supplying a motive fluid at a substantially constant pressure to saidcylinder above and below said piston whereby said fluid will be admitted at the proper time to said cylinder above'said piston to cushion the upward movement and to assist in accelerating descent of said ramand will remain therein at the same constant pressure until said ram has descended to the point of impact to secure a rapid succession of strokes combined with a heavy ram weight for the total weight and striking energy employed, whereupon the fluid will be exhausted by said valve means, said fluid remaining in said cylinder, below said piston during the descending movement of said piston and acting to raise said ram when said fluid above said piston is exhausted.

3. In a pile driving hammer, the combination of acylinder, a piston operating in said cylinder, a ram operated by said piston, a source of fluid supply for maintaining a motive fluid of substantially constant pressure in said cylinder below said piston, and valve means for supplying a motive fluid of substantially the same constant pressure to said cylinder above said piston to cushion the upward movement and exhausting said 'fluid from above said piston as said piston reaches its position of impact whereby motive fluid will simultaneously act on both sides of said piston at a constant pressure until impact of said ram during said downward movement, maintaining the fluid pressure constant against said piston until said point of impact securing a rapid succession of strokes combined with a heavy ram weight for the total weight and striking energy employed.

4. In a pile driving hammer, a cylinder, a piston operating in said cylinder, a ram driven by said piston, means for supplying motive fluid at uniform pressure to said cylinder below said piston whereby the fluid will act to raise said piston, and separate means mechanically engaged by said piston during its movement for controlling the flowof motive fluid regardless of the position of said piston in said cylinder, whereby at the proper time-during the upward movement of said ram motive fluid of the same and uniform pressure as exists in said cylinder below said piston will be supplied to said cylinder above said piston, to cushion upward movement and to assist in accelerating descent of said ram, and to be released therefrom by said separate means after said piston has travelled downwardly to its position of impact, maintaining the fluid pressure constant against said piston until said point of impact securing a rapid successon of strokes combined with a heavy ram weight for the total weight and striking energy employed.

5. The combination in a pile driving hammer, of a cylinder, a piston operating in said cylinder, a ram connected to and driven by said piston, means for admitting fluid continuously at a con stant pressure to said cylinder below said piston, and means automatically controlled and mechanically operated by said piston for admitting and exhausting fluid to said cylinder above said piston only so that the fluid may act over the entire diametrical area of said piston, the actuation of said last means being so arranged as to relieve said cylinder above said piston of any fluid pressure other than atmospheric during the entire period of upward movement of said piston previous to admission of the fluid to said cylinder above said piston, and subsequently, at

the proper time during said upward movement of said piston to allow the fluid at substantially the same pressure as exists in said cylinder below said piston to be supplied to said cylinder above said piston whereby gradually to stop the upward movement of said piston without compressing the motive fluid, and then to continue permitting the continuous supply of the fluid above said piston at the same pressure as exists below said piston, throughout the entire downward movement of said piston until reaching its point of impact to secure a rapid succession of strokes combined with a heavy ram weight for the total weight and striking energy employed, and then to release the fluid from above said piston to atmosphere and there continue again to keep said cylinder above said piston relieved of all pressure during the accelerating period of upward movement of said piston.

6. In a pile driving hammer, the combination of a cylinder, a piston operating in said cylinder, a ram connected to and driven by said piston, means for supplying motive fluid continuously at constant pressure to said cylinder at the annulus below said piston whereby the fluid will act to raise said piston with uniform acceleration, and separate means automatically controlled and mechanically operated by movement of said piston for controlling the flow of the fluid to said cylinder above said piston whereby at the end of the acceleration period of the upward movement of said piston motive fluid of substantially the same constant pressure as exists in said cylinder below said piston will be supplied to said cylinder above said piston to act over the entire diametrical area thereof to aid in uniformly decelerating and to assist in uniformly accelerating descent of said piston, and to be released therefrom by said separate means, automatically controlled and mechanically operated by movement of said piston, after said piston has traveled downwardly to its position of impact to secure a rapid succession of strokes combined with a heavy ram weight for the total weight and striking energy employed, said separate means continuing to relieve said cylinder above said piston from fluid pressure until said piston has again ascended to a point where motive fluid is again admitted.

'7. In a pile driving hammer, a cylinder, a piston in said cylinder, a ram driven by said piston, a source of motive fluid, and means for supplying the fluid above and below said piston at substantially constant unit pressure, said means including a passage in communication with an annulus in said cylinder below said piston for supplying motive fluid thereto continuously from said source, said means also including a valve and a passage having one end communicating directly with said cylinder above said piston while other end of passage is controlled by said valve, and means moving with the piston for positively operating said valve so that when said piston has moved to a predetermined portion of its upward stroke said valve will connect said passage communicating with said cylinder above said piston with said source of motive fluid whereby to supply motive fluid thereto to check the upward movement of said piston, said motive fluid being admitted to said cylinder above said piston at the same constant unit pressure as to said cylinder below said piston, said piston movable means permitting said valve to remain in its said actuated position supplying motive fluid at constant pressure to said cylinder above said piston until said piston has reached the impact position of its down stroke, said piston movable means thereupon actuating said valve through contact to connect said passage with an exhaust and thereafter continuing to keep cylinder above said piston relieved of fluid pressure during the ascending stroke until cushioning period is again reached.

CAMPBELL V. ADAMS.

Images