US3669198A - Fluid operated drop hammer with valved piston - Google Patents

Fluid operated drop hammer with valved piston Download PDF

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Publication number
US3669198A
US3669198A US18239A US3669198DA US3669198A US 3669198 A US3669198 A US 3669198A US 18239 A US18239 A US 18239A US 3669198D A US3669198D A US 3669198DA US 3669198 A US3669198 A US 3669198A
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United States
Prior art keywords
cylinder
piston
ram
spaces
fluid
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Expired - Lifetime
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US18239A
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English (en)
Inventor
Roger M Elliott
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BSP International Foundations Ltd
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BSP International Foundations Ltd
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Assigned to BSP INTERNATIONAL FOUNDATIONS LIMITED reassignment BSP INTERNATIONAL FOUNDATIONS LIMITED CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: BRITISH STEEL PILING COMPANY LIMITED, THE
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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D7/00—Methods or apparatus for placing sheet pile bulkheads, piles, mouldpipes, or other moulds
    • E02D7/02—Placing by driving
    • E02D7/06—Power-driven drivers
    • E02D7/10—Power-driven drivers with pressure-actuated hammer, i.e. the pressure fluid acting directly on the hammer structure

Definitions

  • This invention relates to drop hammers in which a hammer weight is operated by at least one fluid pressure ram.
  • a drop hammer including a fluid pressure operating mechanism comprising a ram having an upwardly extending cylinder and piston assembly, conduit means for interconnecting the spaces of the cylinder on opposite sides of the piston to permit a flow of fluid between said spaces, and valve means for said conduit means to isolate said cylinder spaces from each other, said valve means being displaceable by an increase of pressure within one of the cylinder spaces so as to shut off said flow whereby admission of pressure fluid to the other of said fluid spaces causes relative displacement between the cylinder and piston.
  • Said conduit means may be disposed internally of the ram and pass through the piston.
  • a frame of the hammer has the ram cylinder secured to it by its upper end, the hammer weight being guided by the frame and being secured to a piston rod that projects downwardly from the cylinder and that is attached to said ram piston.
  • Closure of the valve means in this arrange ment may be actuated by an increase in pressure in the cylinder space above the piston so that continuation of a pressure fluid flow to the space below the piston so that continuation of a pressure fluid flow to the space below the piston will then raise the piston and rod.
  • the valve means comprises a displaceably mounted member arranged to be exposed at opposite sides to the fluid in said one space of the cylinder and to atmospheric pressure respectively.
  • Resilient means may bias the member to a position in which the conduit means interconnects said cylinder spaces unless so displaced by a pressure increase in said space to a value substantially greater than atmospheric.
  • the moving part of the ram is connected to the hammer weight by means permitting a limited relative displacement therebetween in the direction of ram movement and damping means are provided to reduce the relative speed between the piston and cylinder at the end of a downwards hammer stroke.
  • damping means may comprise a receiving space to which the ram pressure fluid is supplied and an insertion element for said space, said element and space being associated with the ram piston and cylinder or parts movable with the piston and cylinder respectively, the element being arranged to enter said space during the final part of said downwards stroke, there being a restricted fluid exit from the space while its volume is being reduced by the entry of the element whereby an increased resistance is offered to relative movement between the piston and cylinder during the final part of the stroke.
  • FIG. 1 is a schematic illustration of a drop hammer according to the invention including its hydraulic circuit
  • FIG. 2 is a detailed sectional view of the hydraulic ram of the hammer in FIG. 1,
  • FIG. 3 is a schematic illustration of an alternative form of drop hammer according to the invention.
  • FIG. 4 is a schematic diagram of an automatic switching means for a drop hammer according; to the invention.
  • FIG. 5 is a side elevation, the left-hand half being shown in section, of a modified form of ram for the hammer of FIG. I, and
  • FIG. 6 is a similar side elevation illustrating a further modification of the ram of the hammer of FIG. 1.
  • the hammer comprises a frame 2 that can be mounted upon a pile (not shown) to be driven, a hammer weight 4 being vertically displaceable on guide means 24 of the frame by a hydraulic ram 6 that is attached at the upper end 8 of its cylinder 10 to the frame 2 and at the lower end 12 of its piston rod 14 to the hammer weight, the connection at 15 incorporating resilient shock-absorbing means, such as a rubber bushing.
  • Respective fluid lines l6, 17 lead to connections l8, 19 respectively in the upper and lower ends of the cylinder at opposite sides of a piston 20 slidable in the cylinder and to which the upper end of the rod 14 is secured.
  • the piston 20 has a neck portion 22 threaded to the rod 14 and locked in position by a screw 241.
  • a cylindrical bore 26 opens to the piston upper face and a passage 28 from the lower side of the head leads to an annular recess 30 in the bore wall.
  • a cup-shaped spool 32 fits closely in the bore and is slidable from the position shown, by the action of the spring 34 compressed between the upper end of the rod 14 and a counterbore 36 in the underside of the spool, to bear against a circlip stop 38 at the upper end of the bore 26.
  • an aperture 40 in the cylindrical wall of the spool is aligned with the recess 30 so that there is a through path for hydraulic fluid between the upper and lower cylinder spaces on opposite sides of the piston.
  • the piston rod has a hollow center 42 so that the space occupied by the spring 34, and hence the underside of the spool 32, is in direct communication with the exterior.
  • a hydraulic pump 44 supplies a pressure flow through line 17 to connection 19 of the cylinder.
  • the fluid can flow freely through the piston to the upper part of the cylinder but a pressure relief valve 48 in the upper cylinder line 16 prevents return flow to receiver tank 52 until the pressure at the connection 18 has reached 100 psi.
  • a non-return valve 54 is placed in parallel with the pressure relief valve 48 so that fluid can also bypass the valve 48 to be drawn into the upper cylinder space from the line 16.
  • an enclosed tank 56 can be placed in the line 16 immediately beyond the non-return valve 54 and so provide a readily available source of fluid for this counterflow.
  • the cycle can be repeated, after the hammer weight has impacted the dolly, by switching the control valve 46 again.
  • automatic switching means can be provided so that the cycle is self-repeating.
  • Such means may comprise a port on the side of the cylinder, as indicated at 58, that will communicate with the lower cylinder space when the piston is in its top position, the pressure rise which occurs when the piston attains this position being relayed by control line 60 to operate the valve 46 and so connect the lower space again to the tank return.
  • the switching of the valve 46 to raise the piston and weight can then be actuated by a trip 51 connected by the falling weight immediately before the end of its stroke.
  • the sleeve 64 begins to enter the bore 66 and the seal 70 reaches the wall of the counterbore 68. Fluid in the remaining free volume of the counterbore can then escape to the outlet 19 only through such a clearance as there is between the closely fitting sleeve 64 and wall 66 and through narrow passages 72, 74, 76 leading from the bottom of the counterbore 68, that are controlled by an adjustable restrictor plug 78.
  • the retardation of the piston and piston rod is therefore applied in an increasing rate in the final part of the downward stroke rather than completely suddenly at the end of the stroke, but, because of the resilient connection between the rod and the hammer weight this has little effect on the speed of the weight at impact.
  • a bypass bore 80 is provided to give direct communication between the connection and the main space below the piston and the passages 72, 74, 76 do not therefore restrict the inflow of fluid.
  • the spool 32 may be fixed to or form part of the piston, which would then have limited freedom of movement on the rod 14 to open and close the path between the cylinder spares.
  • springs may be provided to exert a downwards force on the weight, either directly or through its attached ram part, one possible arrangement of such springs being shown at 81 in FIG. 1: this may be required particularly when a construction according to the invention is to be employed for such work as rock-breaking where the ram is likely not to be mounted vertically.
  • FIG. 3 shows a drop hammer in which piston 82 rests on a pile dolly (not shown) while its cylinder 84, which is integral with or is secured to the hammer weight, slides on the piston to impact the dolly.
  • piston 82 rests on a pile dolly (not shown) while its cylinder 84, which is integral with or is secured to the hammer weight, slides on the piston to impact the dolly.
  • Parts similar to those described in the embodiment of FIGS. 1 and 2 are indicated by the same reference numbers and it will be noted that movement of the spool 32 against its spring 34 is now determined by a rise in pressure in the lower space of the cylinder.
  • Fluid lines 16, 17 now connected to the cylinder lower and upper spaces respectively, may form part of an external hydraulic circuit similar to that shown in FIG. 1; the non-return valve 54 and tank 56 are now unnecessary, however, since the total internal volume of the upper and lower cylinder spaces remains substantially constant during operation.
  • pressure fluid is supplied through the line 17 to the upper cylinder space so that when the spool 32 rises to isolate the upper and lower spaces from each other, the continuing flow of fluid from the line 17 raises the cylinder.
  • the arrangement may operate in the same manner as the first-described embodiment and similar damping means may be provided for the end of a working stroke, although these are not illustrated in FIG. 3.
  • FIG. 4 An alternative form of automatic switching means is illustrated diagrammatically in FIG. 4.
  • This comprises a solenoid 100, operating the valve 46 as in FIG. 1 to control the flow to the ram cylinder.
  • a timer 102 having manual adjustment means incorporates in it an amplifier to provide a switching signal to the solenoid 100.
  • the solenoid 100 is energized so that the valve 46 admits hydraulic fluid to the ram cylinder to raise the hammer weight and the timer 102 is simultaneously set in operation.
  • the timer provides a signal to de-energize the valve so that the hammer weight drops.
  • the impact detector 104 On impact of the weight at the end of its stroke, the impact detector 104 generates a signal that sets the timer 102 in operation again and re-energizes the valve solenoid 100 so that the cycle is repeated.
  • FIG. 5 shows a further modified cylinder and piston arrangement, similar in many respects to the construction illustrated in FIG. 1. It may be noted here, however, that the damping means provided are different from that earlier embodiment.
  • the sleeve 64 now carries no collar and lower end bore 66 open into an upwardly widening counterbore 86. As the piston nears the lower end of the cylinder, therefore, the sleeve enters an increasingly restricted passage so that a progressive damping of the ram motion is generated.
  • the resilient connection between the piston rod and the hammer weight prevents this having any significant effect on the speed of the weight at impact.
  • the inlet connection 19 opens into the counterbore 86 so that there is sufficient space between it and the sleeve 64 for the initial inlet flow when the weight is to be raised and no additional bypass connection is necessary.
  • connection between the cylinder spaces is made externally of the cylinder and piston, this being shown in FIG. 6 where a bypass valve arrangement is connected in a conduit 88 between the upper and lower fluid conduits 16, 17.
  • the valve comprises a body 90 housing the valve spool 32 and its spring 34 similarly to the piston in the construction shown in FIG. 1.
  • Passage 92 in the valve body has the aperture 40 of the spool 32 brought into register with it when the spring has forced the spool to its top position.
  • the underside of the spool is subject to atmospheric pressure, in this in stance by the provision of a side bore 94 in the valve body.
  • a drop hammer comprising, in combination, a carrier, a fluid pressure operating mechanism comprising a ram having a cylinder and piston assembly mounted on said carrier in an upwardly extending position, said piston dividing the cylinder interior into discrete spaces on opposite sides of the piston, conduit means arranged to interconnect said cylinder internal spaces, the conduit means being provided with valve means to isolate said spaces from each other, said valve means being displaceable by an increase of pressure in one of said spaces thereby causing a pressure force in that one space, which force displaces said valve means so as to shut off the flow between the spaces whereby admission of pressure fluid to the other of said spaces causes relative displacement between the cylinder and piston.
  • a drop hammer according to claim 1 wherein an upper end of the ram cylinder is secured to the carrier and a piston rod is attached to the ram piston to project downwardly from the cylinder, a hammer weight being secured to the piston rod and guide means being provided on the carrier for said weight.
  • valve means comprises a displaceable member arranged to be exposed at opposite sides to the fluid pressure in said one space of the cylinder and to atmospheric pressure respectively.
  • a drop hammer according to claim 4 wherein resilient means act upon the displaceable valve member to bias it to a position in which the conduit means interconnects said cylinder spaces.
  • a drop hammer according to claim 4 wherein an axial bore is provided in the ram piston in which the displaceable valve member is slidable, said member comprising an outer cylindrical portion sealingly fitting said bore and respective openings being provided in said bore and said cylindrical portion to be mutually registerable to interconnect said cylinder spaces.
  • a drop hammer according to claim 1 wherein a hammer weight is mounted on the carrier to be displaceable by the ram, connection means being provided between the weight and the ram and arranged to permit a limited relative movement therebetween in the direction of ram movement, damping means being provided on the ram to reduce the relative speed between the cylinder and piston at the end of a downwards hammer stroke.
  • a drop hammer according to claim 1 further comprising switching means for automatic cycling operation of the fluid pressure mechanism.
  • a drop hammer comprising, in combination,
  • a fluid pressure operating mechanism including a ram having a cylinder and piston assembly mounted on said carrier in an upwardly extending position, said piston dividing the cylinder interior into discrete spaces on opposite sides of the piston;
  • conduit means arranged to interconnect said cylinder internal spaces, the conduit means being provided with valve means to isolate said spaces from each other, said valve means being displaceable by an increase of pressure in one of said spaces thereby causing a pressure force in that one space, which force displaces said valve means so as to shut off the flow between the spaces, whereby admission of pressure fluid to the other of said spaces causes relative displacement between the cylinder and piston;
  • a hammer weight mounted on the carrier and displaceable by the ram
  • connection means disposed between the weight and the ram, said connection means being arranged to permit a limited relative movement between the weight and the ram in the direction of the ram movement;
  • damping means being provided on the ram to reduce the relative speed between the cylinder and the piston at the end of a downwards stroke, said damping means comprising an insertion element and a receiving space that contains the ram fluid, said element and receiving space being disposed on the ram piston and cylinder, or parts moving with said piston and cylinder, respectively, the element being arranged to enter the receiving space during the final part of the hammer stroke, exit of the fluid from the receiving space being restricted while the volume of the space is being reduced by the entry of the element thereinto, whereby an increased resistance is offered to relative movement between the piston and cylinder during the final art of the stroke.
  • a drop hammer accor ing to claim 9 wherein means are provided to adjust the restriction offered to the exit of the fluid from said space during the final part of said downwards stroke.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Placing Or Removing Of Piles Or Sheet Piles, Or Accessories Thereof (AREA)
  • Percussive Tools And Related Accessories (AREA)
  • Actuator (AREA)
  • Forging (AREA)
US18239A 1969-03-11 1970-03-10 Fluid operated drop hammer with valved piston Expired - Lifetime US3669198A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB02814/69A GB1261220A (en) 1969-03-11 1969-03-11 Improvements in or relating to drop hammers

Publications (1)

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US3669198A true US3669198A (en) 1972-06-13

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US18239A Expired - Lifetime US3669198A (en) 1969-03-11 1970-03-10 Fluid operated drop hammer with valved piston

Country Status (6)

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US (1) US3669198A (ja)
JP (1) JPS4948210B1 (ja)
BE (1) BE747207A (ja)
DE (1) DE2011600C3 (ja)
GB (1) GB1261220A (ja)
NL (1) NL164347C (ja)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4100977A (en) * 1976-05-21 1978-07-18 Bsp International Foundations Limited Drop hammers
WO1997048882A1 (fr) * 1996-06-19 1997-12-24 Nedikov, Vladimir Petrovich Mecanisme de percussion hydraulique
US20190226173A1 (en) * 2016-06-30 2019-07-25 Dawson Construction Plant Limited Pile Hammer

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5115777A (en) * 1974-07-31 1976-02-07 Mitsubishi Heavy Ind Ltd Yuatsusochiniokeru kukikonnyuboshisochi
NL182826C (nl) * 1976-06-15 1988-05-16 Alexander Julien Verstraeten Met een fluidum bedreven hei-inrichting.
JPS54132067A (en) * 1978-04-04 1979-10-13 Nissan Motor Co Ltd Lock-up torque converter
CH629868A5 (en) * 1978-05-11 1982-05-14 Losinger Ag Hydraulic pile hammer
US4172941A (en) * 1978-05-12 1979-10-30 Richardson-Merrell Inc. 7-[2-[ω-(1,3-Dithiolan-2-imino)substituted]-acetylamino]cephalosporanic acid derivatives
DK620184A (da) * 1983-12-29 1985-06-30 Pieter Wilner Apparat til nedramning af paele og fremgangsmaade ved dets anvendelse
CN109340214B (zh) * 2018-12-17 2023-07-18 广东力源液压机械有限公司 一种集成型大功率方向阀油缸及其控制方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7586A (en) * 1850-08-20 Machine for heading- bolts
US1662576A (en) * 1925-09-15 1928-03-13 Demag Ag Valve for pneumatic tools
US1665046A (en) * 1924-10-29 1928-04-03 Ralph H Tucker Pneumatic hammer

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7586A (en) * 1850-08-20 Machine for heading- bolts
US1665046A (en) * 1924-10-29 1928-04-03 Ralph H Tucker Pneumatic hammer
US1662576A (en) * 1925-09-15 1928-03-13 Demag Ag Valve for pneumatic tools

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4100977A (en) * 1976-05-21 1978-07-18 Bsp International Foundations Limited Drop hammers
WO1997048882A1 (fr) * 1996-06-19 1997-12-24 Nedikov, Vladimir Petrovich Mecanisme de percussion hydraulique
US20190226173A1 (en) * 2016-06-30 2019-07-25 Dawson Construction Plant Limited Pile Hammer
US10883242B2 (en) * 2016-06-30 2021-01-05 Dawson Construction Plant Limited Pile hammer

Also Published As

Publication number Publication date
BE747207A (fr) 1970-08-17
NL164347B (nl) 1980-07-15
DE2011600A1 (de) 1970-09-24
NL7003493A (ja) 1970-09-15
JPS4948210B1 (ja) 1974-12-20
DE2011600B2 (de) 1978-08-31
GB1261220A (en) 1972-01-26
NL164347C (nl) 1980-12-15
DE2011600C3 (de) 1979-05-03

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AS Assignment

Owner name: BSP INTERNATIONAL FOUNDATIONS LIMITED

Free format text: CHANGE OF NAME;ASSIGNOR:BRITISH STEEL THE, PILING COMPANY LIMITED;REEL/FRAME:004478/0278

Effective date: 19710824