US3695366A - Hydraulic hammer with back pressure isolation - Google Patents

Hydraulic hammer with back pressure isolation Download PDF

Info

Publication number
US3695366A
US3695366A US87966A US3695366DA US3695366A US 3695366 A US3695366 A US 3695366A US 87966 A US87966 A US 87966A US 3695366D A US3695366D A US 3695366DA US 3695366 A US3695366 A US 3695366A
Authority
US
United States
Prior art keywords
bore
hammer
hydraulic
fluid
venturi
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
US87966A
Other languages
English (en)
Inventor
Ernst F Klessig
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.)
Dresser Rand Co
Worthington Corp
Original Assignee
Worthington Corp
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 Worthington Corp filed Critical Worthington Corp
Application granted granted Critical
Publication of US3695366A publication Critical patent/US3695366A/en
Assigned to DRESSER-RAND COMPANY, CORNING, NEW YORK A GENERAL PARTNERSHIP OF NEW YORK reassignment DRESSER-RAND COMPANY, CORNING, NEW YORK A GENERAL PARTNERSHIP OF NEW YORK ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: DRESSER INDUSTRIES, INC., A DE. CORP.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • 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

  • hydraulic hammer constructions still require further improvement of various peripheral facets of their operation.
  • one difficulty common to many existing commercial hydraulic hammer constructions is the undesirable, uncontrolled variations in the frequency of reciprocation of the hammer element.
  • variations in back pressure in the fluid flow path extending from the piston to the outlet occur, the resistance opposing the driving of the hammer element varies and the rate at which the hammer element is driven will therefore vary.
  • the means for isolating the first surface of the piston from back pressure variations comprises a venturi located downstream of the first surface and in the flow path established therebetween and the outlet during the return stroke of the hammer.
  • the venturi is defined by'an annular projector on a spool serving as the control valve, which land is of lesser diameter than a bore in which the spool reciprocates.
  • FIGURE illustrates a preferred form of a hydraulic hammer embodying the invention.
  • FIG. 1 An exemplary embodiment of a hydraulic hammer made according to the invention is illustrated in the FIGURE and is seen to include a casing, generally designated 10, having a central bore 12 therein. Disposed within the bore 12 for reciprocation therein is a hammer element, generally designated 14, having an upper end including an annular reduced diameter portion 16 and a pressure responsive piston 18. The hammer element 14 also includes a lower, enlarged hammer 20 which is disposed within an enlarged diameter portion 22 of the bore 12.
  • a tool mount 24 Secured to the lower end of the casing 10 is a tool mount 24 having a central bore 26 receiving a movable tool 28 which is disposed to be struck by the hammer 20 and which has a lower, work performing end (not shown).
  • that portion of the tool 28 illustrated could be an anvil having its lower end operatively associated with a selected tool to be used in conjunction with the hammer.
  • the lowerend of such an anvil may ride on the upper end of the tool.
  • the tool 28 includes a key way 30 and a key 32 which extends through the tool mount 24 and the key way 30 to restrict the movement of the tool 28 within the tool mount 24 to the length of the key way 30.
  • the casing 10 includes an inlet 34 which may be connected to any suitable source of hydraulic fluid under pressure to serve as 'a source of energy for reciprocating the hammer 20 within the casing 10 to impart energy to the tool 28.
  • a conventional accumulator 36 In fluid communication with the inlet is a conventional accumulator 36.
  • the casing 10 further includes an outlet 38 and a second accumulator 40 in fluid communication with the outlet 38.
  • a port 42 transverse to the bore 12 in the casing and in fluid communication with the inlet 34 is arranged to permit the application of fluid under pressure to a lowermost surface 44 of the piston 18 of the hammer element 14. As will be seen, this application of fluid under pressure serves to move the hammer element l4 upwardly in the bore 12 for its return stroke.
  • a series of small grooves 45 extend upwardly partially to the port 46 from the port 42 for purposes to be seen.
  • a port 46 normally in fluid communication with the port 42 through the bore 12 and reduced diameter portion 16 provides fluid under pressure to a hydraulically operated control valve spool, generally designated 50, which is operative to control the reciprocation of the hammer element 14 within the bore [2.
  • the spool 50 includes a reduced diameter portion 52.
  • the spool 50 is shiftable within a bore 54 to a first position (illustrated in the FlGURE) wherein fluid under pressure from the inlet 34 passing through the port 42 and the port 46 is fed along the reduced diameter portion 52 to the upper end of the bore 12 via a conduit 56 in communication with both the bore 54 and the bore 12 and applied to an upper surface 58 on the piston 18 of the hammer element 14.
  • the surface 58 is larger than the surface 44 so that when fluid under pressure is applied to the former, notwithstanding the fact that fluid under pressure is also applied to the latter, the hammer element 14 will be driven downwardly to strike the tool 28.
  • a second position of the spool 50 within-the bore 54 is one wherein the spool 50 is shifted upwardly from the position shown in the FIGURE and wherein an enlarged lower end 60 blocks off the path of fluid under pressure from the inlet 34 to the upper end of the bore 12 while an enlarged upper end 62, in conjunction with the reduced diameter portion 52 permits fluid in the upper end of the bore above the surface 58 to exit to the outlet 38 via a conduit 64. lnterposed between the conduit 64 and the outlet 38 and hydraulically prior to the point of connection of the accumulator 40 to the outlet 38 is a restriction or orifice 65 for purposes to be seen.
  • Positioning of the spool 50 is controlled by a differential pin device including pins 66 at the lowermost end of the spool 50 and pins 68 at the opposite end thereof.
  • the pins 66 have a lesser efi'ective area than the pins 68 and are continuously subjected to inlet pressure.
  • the pins 68 are intermittently subjected to inlet pressure dependent upon the position of the hammer 14 within the bore 12 and when such is the case, the spool 50 will be driven by the pins 68 to the position shown. When such is not the case, the pins 66 will drive the spool 50 upwardly to the second mentioned position above.
  • the exemplary embodiment of the invention includes means by which the back pressure against the surface 58 during the return stroke of the hammer element 14 is maintained constant so that cycling frequency will be constant.
  • a venturi is located in the flow path from the upper endof the bore 12 to the outlet 38 and which is established when the valve 50 is in the second position mentioned above.
  • the venturi 70 is carried on the upper end of the reduced diameter portion 52 of the spool 50.
  • the venturi 70 is generally defined by an annular projection having a diameter less than the diameter of the bore 54 and greater than that of the reduced diameter portion 52; an upstream tapered short side 74; and a downstream tapered long side 76. That is, the longitudinal extent of the upstream side 74 of the projection 72 is less than the longitudinal extent of the downstream side 76.
  • annular venturi effectively isolates the pressure in the conduit 56 from pressure variations normally encountered in the return conduit 64.
  • venturi 70 on the spool 50
  • the same could be located at any one of a variety of downstream points in fluid communication with the outlet 38.
  • the casing 10 is generally fonned as a casting and the various conduits contained therein are frequently defined by bores, the forming of a restriction in one of the conduits would require a rather complex machining or casting operation.
  • the formation of the venturi 70 on the spool 50 may be accomplished relatively easily during the formation of the reduced diameter portion 52 thereon.
  • the exemplary embodiment further includes a bypass conduit 80 which extends between the inlet 34 and the outlet 38 and which is normally closed by a bypass valve, generally designated 82.
  • the bypass valve 82 is mounted for reciprocation within a bore 84 in the casing 10. One end of the bore 84 is closed by a plug 86 which serves to position a spring 88 in a recess 90 formed in the body of the valve member 82 to bias the valve member 82 against a seat 92 surrounding the bypass conduit 80.
  • the bypass valve 82 intermediate its ends, includes a reduced diameter portion 93 which normally permits fluid under pressure to flow from the inlet 34 to the port 42 for use in driving the hammer in the manner mentioned previously.
  • the bypass valve 82 further includes a pair of pressure responsive surfaces 94 and 96 with the surface 94 being larger than the surface 96.
  • the recess 90 terminates in a third pressure sensitive surface 98 on the valve 82. The arrangement is such that the combined areas of the surfaces 96 and 98 is greater than the area of the surface 94 but the surface 94 is greater in size than the surface 96 alone.
  • the surfaces 94, 96 and 98 and the spring 88 act such that when'inletpressure is applied against the surface 96 and the surface 94 (as will always be the case) and is applied to the surface 98 (as will usually be the case) the valve 82 will be in the position shown. However, when inlet pressure is not applied to the surface 98, the valve will shift downwardly from the position shown to open the bypass 80 whereupon fluid under pressure from the inlet 34 will flow directly to the outlet 38 bypassing entirely the control valve 50. As
  • the bore section 100 is of slightly greater diameter than the shank of thehammer element 14 but, for-purposes to be seen, is of the same diameter as the diameter of the piston 18.
  • the relief of fluid pressure against the surface 98 so as to permit the valve 82 to open for bypass purposes is accomplished by means of a port 104 in the bottom of a stationary sleeve 1106 embracing the shank of the hammer element 14. Also-included are a series of small grooves 105 extending upwardly a short distance from the port 104 to permit the establishment of fluid communication to the port 104 through the bore section 100 slightly before the reduced diameter portion moves to the upper boundary of the port 104.
  • a channel 108 is in fluid communication with the port 104 and a bore 110 which empties into the hollow center 112 of the spool 50. From the hollow center 112, fluid may flow through a radial bore 114 in the uppermost end of the spool 50 to the conduit 64 to the outlet 38.
  • the arrangement is such that when the hammer element 14 has been driven downwardly past a position wherein it would normally encounter the tool 28 and not yet has encountered the tool, the side of the piston 18 will enter the bore portion 100 thereby blocking fluid communication between the inlet 34 via the port 42 to the surface 98. Simultaneously, the reduced diameter portion 16 on the hammer element 14 will establish fluid communication between the port 102 and the port 104 thereby permitting the fluid under pressure bearing against the surface 98 to flow to the outlet 38 via the path mentioned previously.
  • a hydraulic hammer made according to the invention employing the venturi can be used in a hydraulic system wherein there are large variations in back pressure without affecting the rate of reciprocation of the hammer element during operation thereof.
  • the flow characteristics Fluid under pressure from the inlet 34 is applied to i of the hydraulic fluid around the venturi are such that pressure variations downstream of the same are effectively isolated from the flow path above the venturi so that a constant back pressure will be applied to the piston during the return stroke thereof resulting in a constant rate of operation.
  • a hydraulic hammer comprising:
  • first means establishing constant fluid communication between said second surface and a source of hydraulic fluid under pressure
  • second means alternately establishing fluid communication between said first surface and said source or a hydraulic fluid outlet;
  • means associated with one of said second means and said fluid outlet defining a venturi to maintain back pressure against said first surface at a relatively constant level when said second means establishes fluid communication between said first surface and said fluid outlet.
  • a hydraulic hammer comprising:
  • means for reciprocating said hammer within said bore including 1. means for driving said hammer in one direction within said bore,
  • means including a surface to be subjected to hydraulic fluid under pressure, for driving said hammer within said bore in a direction opposite said one direction, and
  • venturi defining means defining a venturi in said second flow path for isolating pressure fluctuations downstream of the isolating means from fluid in said second flow path and upstream of the isolating means whereby bore in the casing adjacent said first surface and with 10 said fluid outlet, and a valve spool having a reduced diameter portion received within said second bore for reciprocal movement therein to interconnect said fluid outlet and said casing bore end in one position of movement within said second bore; and said venturi defining means comprises an annular projection on said reduced diameter portion having a lesser diameter than the diameter of said second bore.
  • a hydraulic hammer according to claim 5 wherein the sides of said projection are tapered with the side of said projection adjacent said outlet having a greater longitudinal extent than the opposite side of said land.

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)
  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
US87966A 1970-11-09 1970-11-09 Hydraulic hammer with back pressure isolation Expired - Lifetime US3695366A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US8796670A 1970-11-09 1970-11-09

Publications (1)

Publication Number Publication Date
US3695366A true US3695366A (en) 1972-10-03

Family

ID=22208316

Family Applications (1)

Application Number Title Priority Date Filing Date
US87966A Expired - Lifetime US3695366A (en) 1970-11-09 1970-11-09 Hydraulic hammer with back pressure isolation

Country Status (5)

Country Link
US (1) US3695366A (OSRAM)
CA (1) CA935354A (OSRAM)
DE (1) DE2155701C3 (OSRAM)
FR (1) FR2113667A5 (OSRAM)
GB (1) GB1360446A (OSRAM)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3792733A (en) * 1973-02-15 1974-02-19 O Crandall Beet harvesting machine
US3857448A (en) * 1971-11-15 1974-12-31 Proline Ind Pty Ltd Hydraulically operated tamper
US4094365A (en) * 1974-05-20 1978-06-13 Robert Bosch Gmbh Electrohydraulically operated portable power tool
US5052498A (en) * 1989-10-28 1991-10-01 Berema Aktiebolag Portable hammer machine
US20050145400A1 (en) * 2003-12-19 2005-07-07 Clark Equipment Company Impact tool
WO2012052601A1 (en) * 2010-10-21 2012-04-26 Unisto Oy Hammering apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109570421B (zh) * 2018-12-15 2023-11-28 浙江雅晶电子有限公司 一种to管座自动打扁机

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2881739A (en) * 1955-11-23 1959-04-14 Huppert & Co Ltd C Hydraulic percussion tool
US3213615A (en) * 1961-07-11 1965-10-26 Atlas Copco Ab Hydraulically actuated reciprocable tools
CA819486A (en) * 1969-08-05 Worthington Corporation Hydraulic hammer

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA819486A (en) * 1969-08-05 Worthington Corporation Hydraulic hammer
US2881739A (en) * 1955-11-23 1959-04-14 Huppert & Co Ltd C Hydraulic percussion tool
US3213615A (en) * 1961-07-11 1965-10-26 Atlas Copco Ab Hydraulically actuated reciprocable tools

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3857448A (en) * 1971-11-15 1974-12-31 Proline Ind Pty Ltd Hydraulically operated tamper
US3792733A (en) * 1973-02-15 1974-02-19 O Crandall Beet harvesting machine
US4094365A (en) * 1974-05-20 1978-06-13 Robert Bosch Gmbh Electrohydraulically operated portable power tool
US5052498A (en) * 1989-10-28 1991-10-01 Berema Aktiebolag Portable hammer machine
US20050145400A1 (en) * 2003-12-19 2005-07-07 Clark Equipment Company Impact tool
US7156190B2 (en) 2003-12-19 2007-01-02 Clark Equipment Company Impact tool
WO2012052601A1 (en) * 2010-10-21 2012-04-26 Unisto Oy Hammering apparatus
RU2589777C2 (ru) * 2010-10-21 2016-07-10 Мовакс Ой Ударное устройство

Also Published As

Publication number Publication date
CA935354A (en) 1973-10-16
GB1360446A (en) 1974-07-17
DE2155701A1 (de) 1972-05-10
FR2113667A5 (OSRAM) 1972-06-23
DE2155701C3 (de) 1975-10-09
AU3542071A (en) 1973-05-10
DE2155701B2 (de) 1975-02-06

Similar Documents

Publication Publication Date Title
US3664435A (en) Hydraulic hammer with automatic stopping action
US4899836A (en) Hydraulic percussion instrument and method of operating same
US4286929A (en) Dual pressure gas motor, and method of operation
US4062411A (en) Hydraulic percussion tool with impact blow and frequency control
US4878550A (en) Pilot-valve-controlled percussion drilling tool
US4231434A (en) Hydraulic impact device
US3695366A (en) Hydraulic hammer with back pressure isolation
EP0506850A1 (en) ROCK DRILL, HYBRID PNEUMATIC PERCUSSION.
JPH0723722B2 (ja) 流体で作動する衝撃機
US4034564A (en) Piston pump assembly having load responsive controls
US4768589A (en) Downhole hydraulic actuated pump
GB1302759A (OSRAM)
US5064005A (en) Impact hammer and control arrangement therefor
US4450920A (en) Hydraulic reciprocating machines
US4352318A (en) Expandable cushion plunger for piston and cylinder devices
US2119736A (en) Governed fluid operated pump
US4202656A (en) Downhole hydraulically actuated pump with jet boost
US4923373A (en) Hydraulic single piston pump for manual operation
US4341148A (en) Hydraulic sequencing valve
US5984026A (en) Pressure converter
US3853036A (en) Reciprocating fluid motor
US3232176A (en) Percussion tool
GB1043692A (en) Improvements in fluid pressure motive systems, primarily for borehole drilling
US3713367A (en) Fluid pressure operated motors
US4037520A (en) Fluid motor apparatus

Legal Events

Date Code Title Description
AS Assignment

Owner name: DRESSER-RAND COMPANY, CORNING, NEW YORK A GENERAL

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:DRESSER INDUSTRIES, INC., A DE. CORP.;REEL/FRAME:004720/0833

Effective date: 19861231