US3803983A - Reciprocating hydraulic hammer - Google Patents

Reciprocating hydraulic hammer Download PDF

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Publication number
US3803983A
US3803983A US00165539A US16553971A US3803983A US 3803983 A US3803983 A US 3803983A US 00165539 A US00165539 A US 00165539A US 16553971 A US16553971 A US 16553971A US 3803983 A US3803983 A US 3803983A
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US
United States
Prior art keywords
hammer
valve
piston
reservoir
chamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00165539A
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English (en)
Inventor
L Amtsberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chicago Pneumatic Tool Co LLC
Original Assignee
Chicago Pneumatic Tool Co LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Chicago Pneumatic Tool Co LLC filed Critical Chicago Pneumatic Tool Co LLC
Priority to US00165539A priority Critical patent/US3803983A/en
Priority to GB2395172A priority patent/GB1362607A/en
Priority to GB5534472*A priority patent/GB1362608A/en
Priority to CA144,271A priority patent/CA956542A/en
Priority to FR7222037A priority patent/FR2147572A5/fr
Priority to DE19727227134U priority patent/DE7227134U/de
Priority to DE2235817A priority patent/DE2235817A1/de
Priority to US422259A priority patent/US3892279A/en
Priority to CA195,041A priority patent/CA963768A/en
Application granted granted Critical
Publication of US3803983A publication Critical patent/US3803983A/en
Assigned to NATIONAL WESTMINSTER BANK USA reassignment NATIONAL WESTMINSTER BANK USA SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: CHICAGO PNEUMATIC TOOL COMPANY
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
    • F03C1/00—Reciprocating-piston liquid engines
    • F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
    • F03C1/03—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with movement in two directions being obtained by two single-acting piston liquid engines, each acting in one direction
    • F03C1/035—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with movement in two directions being obtained by two single-acting piston liquid engines, each acting in one direction one single-acting piston being always under the influence of the liquid under pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D9/00—Portable percussive tools with fluid-pressure drive, i.e. driven directly by fluids, e.g. having several percussive tool bits operated simultaneously
    • B25D9/06—Means for driving the impulse member
    • B25D9/12—Means for driving the impulse member comprising a built-in liquid motor, i.e. the tool being driven by hydraulic pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L23/00—Valves controlled by impact by piston, e.g. in free-piston machines
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S173/00—Tool driving or impacting
    • Y10S173/04—Liquid operated

Definitions

  • a feature of the invention lies in the employinent of an hydraulically operable piston for driving the hammer on a work stroke, an in an hydraulically operable plunger for automatically returning the hammer and piston to starting position.
  • Another feature lies in a pressurized oil reservoir defined by a jacket in surroundingrelation to an end portion of the tool, whereby the paths of fluid flow to'effect operation of various elements of the tool are shortened to a minimum with consequent reduction of energy losses that would otherwise arise from leakage and friction.
  • Another feature of the invention lies in a slide valve incorporated in the tool to control flow of reservoir oil to and from one end of the driving piston.
  • the valve is shifted mechanically near the end of the return stroke by means of the returning piston; and is shifted under hydraulic pressure from the reservoir during the work stroke.
  • a further feature lies in the use of plungers hydraulically dampened by reservoir oilto absorb energy of the moving hammer beyond its usual impacting position.
  • Another feature lies in a. dumping plunger valve which is responsive to pressure of reservoir oil to cause dumping of fluid from the reservoir and dissipation of its energy, when the hammer has moved to a predetermined low position as when the tool is removed clear of the work or when the work steel has suddenly dropped into a void area.
  • a still further feature of the invention lies in the organized arrangement of the return plunger, the damping plungers, the dumping valve, and an hydraulically operable ram for shifting the control valve in one direction whereby this arrangement they are all directly subject to constant pressure of oil in the reservoir for their operation.
  • FIG. 1 is a longitudinalsectionn of an hydraulic hammer illustrating the invention, which view is taken on line l-] of FIG. 2; i I
  • FIG.-2 is a plan view of the top end of FIG. 1;
  • FIG. 3 is a section taken an line 33 of FIG. 1;
  • FIG. 4 is a section taken on line 44'of FIG. 1;
  • FIG. 5 is a section taken on line 5-5 of FIG. 1;
  • FIG. 6 is a longitudinal section taken on line 66 of FIG. 5;
  • FIG. 7 is an enlarged detail of the valve mechanism shown in FIG. 6.
  • the hydraulically operable hammer illustrating the invention is designed primarily for use as a pavement breaker.
  • the tool is mountable to a boom (not shown) on a motor vehicle by means of brackets 10 (FIG. 5) fixed to a side area of the tools housing 11.
  • the boom is hydraulically operable to selectively raise or lower the tool so as to bring a work steel 12 into or out of pressed relation with the work.
  • the general housing Ill includes a fronthead l3 bolted at 14 in end relation to an elongated cylinder or jacket section 15.
  • the cylinder provides a chamber 16 which serves as a pressure oil reservoir.
  • the reservoir is sealed at its rear by means of an end wall I7 and is sealed at its opposite end by means of an annular shoulder 18 provided by the fronthead 13.
  • An inlet 19 to the reservoir is connected by means of a hose line 21 with an hydraulic pressure supply system 20 mounted upon the motor vehicle.
  • the supply system is equipped with suitable controls which enable it to be employed, not only for hydraulically filling and pressurizing the reservoir, but also for hydraulically operating the boom.
  • an internal or second housing 22 Axially arranged within the reservoir in spaced relation to the end wall 17 and to the surrounding wall of the reservoir is an internal or second housing 22.
  • the latter includes a lower section 23 having an annular wall, the bottom end of which is seated upon the shoulder 18.
  • Housing section 23 defines a cylindrical hammer chamber 24 which connects directly with a coaxial bore 25 extending through the fronthead.
  • the work steel is slidably received in the fronthead and it projects at its tail end into the hammer chamber where it is subject-to being pounded by the hammer.
  • a retaining cap 28 threadedly engaged over the forward end of the fronthead has an internal shoulder 29 which is cooperable with a flange or collar 31 located intermediately of the ends of the work steel to retain the latter within the tool against endwise escape.
  • the collar 31 is also cooperable with a second shoulder 32 within the fronthead to limit the extent of projection of the work steel into the hammer chamber.
  • the hammer is caused to be driven on a work stroke under pressure of reservoir hydraulic fluid applied to an integral piston portion 34 of the hammer and it is adapted to be mechanically returned under pressure'of the reservoir fluid applied to an end of a return plunger 35.
  • the piston 34 is defined by means of an elongated stem that is fixed axially to the hammer but is of relatively reduced diameter.
  • the piston is slidably received in a bushing 36 fixed by bolting in a backhead section 37 of the internal housing.
  • the backhead 37 seals over the rear end of the hammer chamber 24 and it is rigidly seated upon an annular rear end wall 38 of the lower housing section 23 by means of a group of bolts 39.
  • the bolts pass through side ears 41 of the backhead and are threadedly tightened in the annular shoulder 18.
  • the backhead defines a piston chamber 42 rearwardly of the piston.
  • a shuttle valve 43 (FIGS. 1, 6, 7) axially slidable in the piston chamber rearwardly of the piston, controls the application to and relief of reservoir hydraulic pressure fluid from the piston.
  • the valve is slideable between a pair of axially spaced annular shoulders 44 and 45 of the piston chamber to open and closed positions relative to a ring of oil feed ports 46 and a ring of oil discharge ports 47 formed in a valve bushing 48.
  • the rearwardly disposed shoulder 45 is defined by the inner face of a plug 49 bolted to the upper end of the backhead over the piston chamber.
  • the feed ports 46 connect through an annulus with a group of larger feed ports 51 communicating with the reservoir 16.
  • the discharge ports 47 connect through an annulus with a larger discharge port 52 that opens laterally into a return line passage 53.
  • the latter leads to an outlet 54 provided by an adapter 55.
  • the adapter is bolted to the external face of the end wall 17.
  • the outlet connects by means of a nose line 56 with a sump (not shown) in the external hydraulic pressure supply system.
  • the return passage 53 is defined in part by means of a tube 57 (FIG. 1) that is fixed at its lower end in an offset portion of the backhead 37 (FIG. 4), extends through the back wall 17 and is fixed in the adapter 55.
  • the return passage also connects by means of a second large discharge port 58 with an annulus 59 surrounding the piston bushing 36.
  • a group of relief ports 61 in the piston are registrable during a work stroke of the piston with a group of drain ports 62 in the piston bushing 36 to relieve pressure oil from a cavity 63 in the piston through the annulus 59 to the return passage 53, as in FIG. 1.
  • the relief ports 61 are blocked off and a group of feed ports 64 in the piston become connected with the piston chamber 42 to admit reservoir pressure oil to the piston cavity 63, as in FIGS. 6 and 7.
  • the shuttle valve 43 is defined by an open ended cylindrical body or skirt which is slidable to cover and uncover the several feed and discharge ports 46 and 47.
  • the body of the valve is joined by means of a group of radial spokes 65 (FIGS. 4, 7) with an axially extending valve operating rod 66.
  • An upper section of the valve rod rearwardly of the spokes extends slidably into an axial bore 67 of the plug 49.
  • the bore is extended by means of a relatively reduced counterbore 68 through a terminal stem 69 of the plug.
  • a ram 71 slidable in this counterbore 68 constantly abuts the upper end of the valve rod under ambient pressure of reservoir fluid.
  • the ram 71 functions under pressure of reservoir fluid to slide the valve forwardly or downwardly so as to uncover the discharge ports 47 and to cover the feed ports 46 preparatory to a subsequent return stroke, as appears in FIG. 1.
  • a longer oppositely lower extending section of the valve rod extends slidably through a bushing or adapter 72 into the piston cavity 63.
  • the valve rod is of reduced diameter relative to that of the cavity so as to provide a surrounding clearance allowing communication of the cavity with the piston feed ports 64.
  • the adapter 72 includes a flange which is bolted over the and of the piston.
  • the adapter has a lower sleeve or stem portion which guides the valve rod and extends into the piston cavity. This stem is of reduced diameter relative to the piston cavity so as not to block communication of the piston cavity with the ports 64.
  • the adapter 72 has an oppositely upper extending sleeve or stem 73 which also guides the valve rod and projects with a substantial surrounding clearance into the piston chamber 42 rearwardly of the piston.
  • stem 73 On a return stroke of the piston, the stem 73 is carried freely into the interior of the valve 43 so as to abut the spokes 65 and slide the valve to a partially shifted condition, as appears in FIGS. 6 and 7.
  • the drain or return ports 47 are covered and the feed ports 46 are uncovered.
  • the side ports 64 of the piston are brought into communication with chamber 42; and, as the valve is being shifted pressure fluid enters through ports 46 to chamber 42 from where it enters ports 64 to fill and pressurize the piston cavity 63.
  • the pressure developing in chamber 42 and the cavity 63 decelerates the returning piston and causes its return movement to stop slightly short of and before the face of the hammer can bottom against the stationary flange 74.
  • the pressurization of cavity 63 exerts a bias over the lower end of the valve rod to shift the valve away from the piston for a slightly further distance until the valve abuts the upper shoulder 45. Reservoir pressure acting over the smaller diameter end of the ram 71 is insufficient to resist this further shifting action.
  • the hydraulic bias in cavity 63 acting on the valve rod serves to hold the valve in its open and fully shifted condition until the pressure in cavity 63 is subsequently relaxed which occurs at about the time of impacting action of the hammer during a work stroke. following shifting of the valve to its open condition, rapid pressurization of chamber 42 acts upon the piston to drive it over a forceful work stroke.
  • the manner in which the piston hammer is returned and in which the valve is shifted to its open condition is of decided advantage.
  • the hydraulic deceleration and stopping of the returning piston before the hammer can contact the stationary flange 74 avoids undesirable forces being imparted 'by the hammer to the internal housing 22.
  • the hydraulic stopping of the piston before it can shift the valve into abutment with the end shoulder 45 also is of decided advantage in that undesirable compressive forces of the piston upon the valve are avoided.
  • hammer and piston are shown in a preferred form as an integral unit, they may be incorporated in the tool as separate elements.
  • the reservoir 16 connects separately with each plunger bore by means of a restricted passage 79 in the wall of the fronthead with ports 82 that are located a shorst distance above the bottom of the plunger bore. Reservoir pressure fluid entering the plunger bore biases the plunger upwardly until a tapered upper shoulder abuts a complementary shoulder of the bore. In this condition, a reduced diameter stem 81 of the plunger projects into the hammer chamber. The upper end of the stem 81 of each plunger will normally be cooperable with the opposed underface of the hammer during a work stroke.
  • the plungers 76 have a slight taper about their lower ends normally positioned opposite the ports 82 so as to restrict flow through the latter back to the reservoir as the plungers are pressed downwardly by the hammer. This flow is further restricted as the plungers are moved further down by the hammer to carry their tapered ends in further restricted relation to the ports 82.
  • the hammer 26 is caused to be returned upon completion of its work stroke by means of the hydraulically biased return plunger 35 (FIGS. 6, 3).
  • the plunger is slidable in parallel relation to the axis of the hammer in an eccentrically located bore provided by a bushing 83 fitted in the shoulder 18 of the fronthead.
  • the underside of the bore is connected with the reservoir by a passage 84 opening into the reservoir through the shoulder 18 of the fronthead.
  • Pressure fluid from the reservoir constantly filling the passage 84 continuously pressurizes the plunger into abutment with the underface of the hammer.
  • the passage 84 is sufficiently large enough to allow rapid escape to the reservoir of fluid displaced by the plunger when the hammer is moving downward on a work stroke.
  • the shuttle valve 43 When the shuttle valve 43 is caused to be shifted toward the end of a work stroke by the ram 71 so as to discontinue application of reservoir oil to the piston andto open the piston chamber 42 tothe return line 53, the pressure of oil in the reservoir then effectively acts through the passage 84 upon the return plunger 35 to move the hammer on areturn stroke.
  • the diameter of the return plunger is relatively small so as to permit a desired easy or slowed return of the hammer.
  • a dumping plunger valve 85 (FIGS. 5, 6) is provided to cause the reservoir oil to bed umped and its energy relieved through the return line 53 when the tool is lifted from the work. This dumping action prevents the piston from being returned from a work stroke by the return plunger 35. This is desired to immediately stop further undesirable reciprocation of the hammer.
  • the dumping valve extends parallel to the piston and hammer and is slidablein'a busning 86 fitted in an offset side portion of the backhead 37.
  • the dumping valve has an upper flat end which normally projects into the reservoir 16; its opposite lower end projects through the bushing 86 and is in constant contact with the upper surface of the hammer 26 under bias of reservoir oil pressure.
  • the dumping valve normally blocks communication of the reservoir through the bushing 86 with a dumping port 87. The latter is connected by the annulus 59 with the return passage 53.
  • a conventional pressure surge accumulator 88 (FIGS. 1, 2) is connected with the outlet passage 54 as a protective measure to reduce the pressure of the returning fluid on the return hose 56.
  • the inlet feed line 21 is continuously open so that the reservoir 16 in which the internal housing 22 is fully immersed is completely filled and constantly pressurized with fluid continuously being supplied to it from the hydraulic system.
  • This huge volume of reservoir oil serves as an accumulator due to its compressibility. It is of such volume that it will feed one stroke of the piston with a pressure drop of less than 800 p.s.i. in the reservoir.
  • the close proximity of the reservoir to the internal housing and to the piston chamber therein facilitates an extremely high flow rate that occurs when the hammer has attained its maximum velocity just prior to impacting.
  • the annulus style reservoir 16 in surrounding relation to the internal housing provides very convenient access of pressure fluid for obtaining the auxiliary functions of the return plunger 35, the damping plungers 76, the dumping valve 85, and the ram 71, all of which are directly exposed to reservoir fluid.
  • Reservoir pressure fluid then flows through feed ports 46 to chamber 42 and through the piston feed ports 64 to pressurize the piston cavity 63.
  • the fluid pressure then developing about the returning piston acts to decelerate its movement and brings it to a stop before its end wall 75 can abut against the stationary wall 74 and before its stem portion 73 can shift the valve into abutment with the upper shoulder 45, all as earlier explained.
  • the pressure developing in the piston cavity 63 acts to bias the valve to its fully shifted condition and to hold it there until the subsequent work stroke of the piston is substantially completed.
  • the pressure developing over the piston finally drives the piston on a forceful work stroke into impacting relation with the work steel 12.
  • the return plunger 35 On the work stroke, the return plunger 35 is moved ahead by the hammer to force the oil below it through passage 84 back into the reservoir.
  • the energy being imparted by the return plunger to the oil forced back to the reservoir is added to the energy of the reservoir fluid acting upon the piston to further increase the drive and impacting force of the hammer.
  • the piston and hammer automatically recycle until the work steel obtains a low condition wherein its collar 31 abuts the shoulder 29 of the retaining cap.
  • the work steel may obtain this low or dropped condition wherein the return plunger is disabled from returning the hammer and piston, not only when the work steel drops into a void or soft ground area, but also when the tool is lifted by the operator out of its pressed relation to the work.
  • the hammer is progressively dampened by the plungers 76, as earlier explained.
  • the hammer will automatically resume its cycling when the operator actuates the boom to carry the tool to a new position in pressed relation of the work steel to the work.
  • the dumping valve 85 is held in constant abutment with the hammer under pressure of the reservoir fluid and moves in unison with the hammer.
  • the stop serves to prevent the dumping valve from sliding free of its bushing 86 and dropping into the reservoir should the tool, for some reason, be turned front end up, as may occur during portage of the tool apart from the boom.
  • a reciprocating hydraulic hammer including a fronthead having an annular shoulder at a rear end thereof, an outer housing fixed at a base end to the shoulder, an inner housing confined within the outer housing and also fixed at a base end to the shoulder, the outer housing defining a reservoir surrounding the inner housing and filled with pressurized hydraulic fluid, an inlet through the outer housing connected with an external system for maintaining the reservoir continuously filled and pressurized with hydraulic fluid, a hammer reciprocable in the housing to pound a work steel received in the fronthead, a plunger biased against a bottom end of the hammer by pressure of the fluid in the reservoir urging the hammer on a return stroke, a piston above the hammer having an end of a diameter greater than that of the plunger subject to pressure of hydraulic fluid from the reservoir to drive the hammer on a work stroke, the piston having unitary movement with the hammer on a return stroke of the hammer, and valve means having response to movement of the piston on a return stroke to communicate the reservoir with the said end of
  • a reciprocating hydraulic hammer comprising a cylinder, a hammer piston reciprocable therein having an end subject to hydraulic pressure to drive it on a work stroke, a chamber in the cylinder adjacent said end, hydraulic pressure fluid feed ports to the chamber, a shuttle valve in the chamber controlling application of fluid through the feed ports to the chamber to drive the piston, the valve being shiftable in one direction to a condition closing the feed ports and shiftable in an opposite direction to an initial position opening the feed ports and to a further position abutting an end of the chamber, first biasing means constantly biasing the valve to its closing condition, means for returning the piston following a work stroke, means carried by the piston having cooperation with the valve on its return movement to shift the valve against the biasing means to its initial position opening the feed ports, means for hydraulically arresting the return movement of the piston as the valve obtains its initial position, and means subject to pressuree of fluid entering the chamber through the feed ports to bias the valve to its further position against the opposed first biasing means.
  • a reciprocating hydraulic hammer including a cylinder, a valve chamber in the cylinder, a piston hammer reciprocable in the cylinder having one end exposed to the chamber, radial inlet ports for admitting hydraulic pressure fluid to the chamber to drive the piston on a work stroke, radial drain ports axially spaced from the inlet ports for relieving the chamber of said fluid, and a shuttle valve for controlling admission of the fluid through the inlet ports and its relief through the drain ports; wherein the shuttle valve has a cylindrical open ended body movable in one direction to uncover the inlet ports and to cover the drain ports and movable in the opposite direction to obtain a reverse condition relative to the inlet and drain ports, a rod extending axially through the interior of the body of the valve and projecting beyond opposite ends thereof, and

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Percussive Tools And Related Accessories (AREA)
US00165539A 1971-07-23 1971-07-23 Reciprocating hydraulic hammer Expired - Lifetime US3803983A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
US00165539A US3803983A (en) 1971-07-23 1971-07-23 Reciprocating hydraulic hammer
GB2395172A GB1362607A (en) 1971-07-23 1972-05-22 Tool having a hydraulically reciprocable hammer
GB5534472*A GB1362608A (en) 1971-07-23 1972-05-22 Tool having a hydraulically reciprocable hammer
CA144,271A CA956542A (en) 1971-07-23 1972-06-08 Reciprocating hydraulic hammer
FR7222037A FR2147572A5 (de) 1971-07-23 1972-06-19
DE19727227134U DE7227134U (de) 1971-07-23 1972-07-21 Hydraulischer kolbenhammer
DE2235817A DE2235817A1 (de) 1971-07-23 1972-07-21 Hydraulischer kolbenhammer
US422259A US3892279A (en) 1971-07-23 1973-12-06 Reciprocating hydraulic hammer
CA195,041A CA963768A (en) 1971-07-23 1974-03-14 Reciprocating hydraulic hammer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00165539A US3803983A (en) 1971-07-23 1971-07-23 Reciprocating hydraulic hammer

Publications (1)

Publication Number Publication Date
US3803983A true US3803983A (en) 1974-04-16

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ID=22599335

Family Applications (1)

Application Number Title Priority Date Filing Date
US00165539A Expired - Lifetime US3803983A (en) 1971-07-23 1971-07-23 Reciprocating hydraulic hammer

Country Status (5)

Country Link
US (1) US3803983A (de)
CA (1) CA956542A (de)
DE (2) DE2235817A1 (de)
FR (1) FR2147572A5 (de)
GB (2) GB1362607A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4165788A (en) * 1976-11-08 1979-08-28 Roger Montabert Hydraulic percussion apparatus
US4402370A (en) * 1981-05-15 1983-09-06 Abraham Gein Valveless pneumatic hammer
US4560207A (en) * 1984-03-01 1985-12-24 Caterpillar Tractor Co. Method and apparatus for fragmenting asphalt
US4850437A (en) * 1986-11-20 1989-07-25 Sudnishnikov Vadim B Single-blow pneumatic percussive tool
US20120195760A1 (en) * 2011-01-31 2012-08-02 Eurocopter Lead-lag damper device
US10821308B1 (en) * 2015-09-21 2020-11-03 David Krumrei Battering ram

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE7902872L (sv) * 1979-03-30 1980-10-01 Atlas Copco Ab Pneumatisk slagmekanism

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US384186A (en) * 1888-06-05 earth
US2960067A (en) * 1957-10-28 1960-11-15 Inv S Man Corp Single stroke air hammer
US3322038A (en) * 1964-04-09 1967-05-30 Sperry Rand Corp Hydraulic hammer
US3351256A (en) * 1965-10-05 1967-11-07 Bostitch Inc Fluid actuated driving apparatus
US3468222A (en) * 1966-07-06 1969-09-23 Hugo H Cordes Control for a ramming hammer with hydraulic drive
US3552269A (en) * 1968-03-27 1971-01-05 Krupp Gmbh Hydraulically operable linear motor

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US384186A (en) * 1888-06-05 earth
US2960067A (en) * 1957-10-28 1960-11-15 Inv S Man Corp Single stroke air hammer
US3322038A (en) * 1964-04-09 1967-05-30 Sperry Rand Corp Hydraulic hammer
US3351256A (en) * 1965-10-05 1967-11-07 Bostitch Inc Fluid actuated driving apparatus
US3468222A (en) * 1966-07-06 1969-09-23 Hugo H Cordes Control for a ramming hammer with hydraulic drive
US3552269A (en) * 1968-03-27 1971-01-05 Krupp Gmbh Hydraulically operable linear motor

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4165788A (en) * 1976-11-08 1979-08-28 Roger Montabert Hydraulic percussion apparatus
US4402370A (en) * 1981-05-15 1983-09-06 Abraham Gein Valveless pneumatic hammer
US4560207A (en) * 1984-03-01 1985-12-24 Caterpillar Tractor Co. Method and apparatus for fragmenting asphalt
US4850437A (en) * 1986-11-20 1989-07-25 Sudnishnikov Vadim B Single-blow pneumatic percussive tool
US20120195760A1 (en) * 2011-01-31 2012-08-02 Eurocopter Lead-lag damper device
US8985950B2 (en) * 2011-01-31 2015-03-24 Airbus Helicopters Lead-lag damper device to limit an end-of-stroke force peak
US10821308B1 (en) * 2015-09-21 2020-11-03 David Krumrei Battering ram

Also Published As

Publication number Publication date
GB1362607A (en) 1974-08-07
GB1362608A (en) 1974-08-07
DE2235817A1 (de) 1973-02-01
DE7227134U (de) 1973-05-24
CA956542A (en) 1974-10-22
FR2147572A5 (de) 1973-03-09

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Owner name: NATIONAL WESTMINSTER BANK USA, 175 WATER STREET, N

Free format text: SECURITY INTEREST;ASSIGNOR:CHICAGO PNEUMATIC TOOL COMPANY;REEL/FRAME:004681/0047

Effective date: 19861230