US3815766A - Backhoe swing mechanism - Google Patents
Backhoe swing mechanism Download PDFInfo
- Publication number
- US3815766A US3815766A US00123460A US12346071A US3815766A US 3815766 A US3815766 A US 3815766A US 00123460 A US00123460 A US 00123460A US 12346071 A US12346071 A US 12346071A US 3815766 A US3815766 A US 3815766A
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- US
- United States
- Prior art keywords
- hydraulic
- motors
- support bracket
- swing
- motor
- 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
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
- F15B11/20—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors controlling several interacting or sequentially-operating members
Definitions
- This invention relates to a novel combination of elements so arranged and so designed as to provide pivotal movement of any mechanism about a relatively fixed pivot point.
- the apparatus will find application in backhoes in which a backhoe boom is swung about a vertical axis or in an articulated vehicle as a steering means to pivot the front and rear section with relation to each other, or finally in any other apparatus in which rotational or swing movement about axis is desired.
- the torque developed by the swing structure should be as great as possible, be uniform across the entire movement, and have a relatively high, uniform velocity.
- a cushioning device should be included at each end of the swing stroke to reduce to a minimum the impact of the swing unit when it meets a mechanical stop at the end of the movement.
- Conventional swing systems utilize two conventionally plumbed cylinders and mechanical linkages that provide the 180 swing movement required. Normally, one cylinder provides the total swing movement in one direction while the other cylinder provides the total movement in the opposite direction.
- Mechanical linkages or trunnion elements are used to convert the straight line cylinder motion into the circular motion required to swing the unit.
- External rubber bumpers are used at the end of the stroke to reduce the impact of the unit when the system reaches the end of its rotational movement, and control valve unlatch devices are often used to cut the power at the end of the stroke in an attempt to reduce impact by reducing the torque at this critical time.
- the preferred embodiment of the present invention is a combination of two hydraulic motors operating between a fixed support and a pivotal member and having one or more novel subcombinations employed therewith.
- These novel units include a sequence valve which senses the position of the swing member and directs hydraulic energy to the motors in such a manner as to obtain more desirable qualities of torque output delivered to the swing member.
- a check and relief valve unit has been designed to further smooth out the variable torque characteristics delivered to the swing member by providing resistance to swing during certain phases of the swing movement and to prevent runaway load and thus check cavitation.
- a third subcombination involves a bleeder unit which is designed to reduce the system input energy to a minimum and still maintain a desirable velocity with full torque (at system pressure) when the swing unit is near the rotational limit of its swing.
- This bleeder unit in conjunction with other elements also provides for a smooth deceleration to the rotational velocity when the swing member approaches the end of its rotational movement.
- a swing bracket member is also used which provides space and construction advantages desirable in a backhoe.
- FIG. 1 is a side elevational view of the subject matter of this invention incorporated into the stand of a backhoe and operating to pivot the boom;
- FIG. 2 is a plan view of the apparatus taken partly in section and disclosing the fluid circuit, the hydraulic motors, and the sequence valves as attached to the support stand for the backhoe;
- FIG. 2A is a sectional view of a one-way restrictor employed in a port of the hydraulic motor
- FIG. 3 is a sectional view of the sequence valve taken along a horizontal center line so as to disclose the components thereof;
- FIG. 4 is a view disclosing the hydraulic motors and the sequence valves partially in section and the hydraulic circuit schematically for operating the apparatus. This view discloses the apparatus in stage 1 of its operation;
- FIG. 5 is a similar view to FIG. 4 disclosing the apparatus in stage 2 of its operation;
- FIG. 6 is a similar view to FIG. 5 disclosing the apparatus in stage 3 of its operation;
- FIG. 7 is a similar view to FIG. 6 disclosing the apparatus in stage 4 of its operation;
- FIG. 8 is a perspective view of the forward section of the backhoe stand with portions broken away disclosing the mounting of the hydraulic motors and sequence valves;
- FIG. 9 is a view disclosing the hydraulic rams and sequencevalve operating on a trunnion block.
- FIG. .10 is a plan view disclosing the invention in its association with an articulated vehicle when employed as a steering means.
- the invention is incorporated in a backhoe B which is mounted on a tractor T in a conventional and well-known manner.
- the backhoe comprises the support stand S having stabilizer arms A which provides a stabilized platform for the mast N of the backhoe.
- the mast N supports a dipper stick D which in turn supports a bucket or shovel R and hydraulic motors M are pro-. vided to perform the digging operation.
- Other conventional details of the backhoe are not enumerated unless material to our invention.
- This swing and support bracket 10 has a U-shaped cutout portion formed by vertical section 12, horizontal flange sections 11, I1
- FIG. 2 The circuit which controls the proper expansion and contraction of each of the hydraulic motors 20 and 20 is disclosed in FIG. 2.
- the right motor and its component parts will be referred to by an integer and the left cylinder and its components will be designated by the same integer with an additional prime mark.
- a three position, four-way flow control valve V may be employed.
- Such a valve is conventional and well known in the art and may additionally include such elements as crossover relief valves and system or circuit relief valves.
- Directing fluid to this directional control valve V is a conduit 51 and an exhaust conduit 52 which are connected to the conventional tractor hydraulic system (not shown).
- the valve V then directs fluid alternatively to parallel circuit 55 or 56 and exhausts fluid from the opposite circuit.
- Parallel circuit 53 has a branch conduit 60 leading to port of sequence valve 200 and a second branch conduit 61 leading to port 101 of sequence valve 200'.
- Parallel circuit 56 has a branch conduit 62 leading to port 101 of sequence valve 200 and a branch conduit 63 leading to port 100 of sequence valve 200'.
- Sequence valve 200 is then connected to hydraulic motor 20 by a first conduit 64 which enters the hydraulic cylinder through inlet 104 and is connected to the sequence valve 200 at port 102.
- a second conduit 65 conducts fluid from port 103 of sequence valve 200 to the upper end of hydraulic motor 20 through port 105.
- Identical conduits connect sequence valves 200' with hydraulic motor 20 through ports 102', 103', 104 and 105 in the same manner as disclosed for the right hydraulic motor and sequence valve.
- the hydraulic motors 20 and 20 are of the structure amply disclosed in US. Pat. No. 3,296,942 issued to V.A. Nelson and reference is made to that patent for a more complete disclosure. However, the major features (see FIG. 2) will be herein pointed out.
- the hydraulic motor 20 comprises a cylinder 22 having operating therein a reciprocating piston 23 which acts upon piston rod 21.
- the rod 21 passes through the piston 23 and extends therebeyond a distance such that a retaining member 24 may be held thereon by a nut 25.
- the retaining member 24 is cup-shaped, having a disk 30 surrounding the rod 21 and a flange 26 for holding a ring 27 thereon.
- the ring 27 is a short cylindrical member which is carried by the retaining member 24 in a loose manner such that the ring has limited movement in a direction perpendicular to the rod 21. V-shaped grooves or troughs 28 are then placed in the exterior surface of the ring 27. Assume now that the piston 23 of hydraulic cylinder 22 is being retracted and that fluid is being displaced from the head end of this cylinder. As the ring 27 moves downwardly in juxtaposition with the inlet of the cylinder, the efflux jet moves it into a close fitting relationship with the port 104 and would restrict fluid flow from the head end of the cylinder but for the grooves 28 which meter the hydraulic fluid at a decelerated rate.
- a oneway restrictor 119 and 119' arranged in conjunction with ports 104 and 104. (See FIGS. 2 and 2A).
- the coupling element for port 104 has therein an enlarged chamber 120 which houses a disk-like insert 121 whose diameter may be somewhat less than the diameter of the chamber 120.
- the insert 121 is additionally provided with an aperture 122 through its center and grooves 123 across its lower face.
- flow out of chamber A causes the insert 121 to seat against surface 125 and the flow is restricted to metering orifice 122.
- These one-way restrictors 119 and 119' also have an independent function of preventing cavitation as will be later explained.
- sequence valves 200, 200 Interconnected between the motors 20, 20' and the support stand S are sequence valves 200, 200. These valves are pivotally connected to the support stand at 41, 41' and the hydraulic motors at 42, 42. The right sequence valve will now be described in detail (FIG. 3)
- a housing 201 having a bore 202, passing therethrough.
- Reciprocable within this bore 202 is a threaded spool 203 which is further connected to an eye bolt 204 mounted on pivotal connection 42.
- the spool 203 is sealingly reciprocated within valve housing 201 by a collar 205 and O-rings 206 and 207 as shown.
- a snap ring 208 holds the collar 205 within the housing 201.
- the spool itself is provided with a bored center section 209 extending from the bottom of the spool upward to the midpoint of the spool.
- the spool 203 is cross-drilled at 210 adjacent the upper end of bored passage 209 and at 211 which is near the midsection of the bored passage 209.
- a groove 212 is provided near the midsection of the bored passage 209 so as to be concentric about cross drill 211.
- This groove 212 is further provided with metering notches 213 and 214 near its extremities.
- the central bore 202 of the valve housing 201- is also provided with four annular grooves.
- the first groove 220 is adjacent a passage 230 which leads through a restrictor 231, a check valve 251 to port 101.
- a second groove 221 also leads to port 101 through a second passage 235.
- a third groove 222 leads to port 103 through a channel 240 while groove 223 leads directly to ports 100 and 102 of sequence valve 200.
- sequence valve 200 senses the position of its associated hydraulic motor in its rotational movement about pivot 40, 40 and to direct the flow of input fluid to the proper side or sides of the piston 23 so as to obtain the desired torque output on the support bracket 10.
- the valve has two basic positions as shown in FIG. 4. In this stage of operation sequence valve 200 is in the fully open position while sequence valve 200 is in the fully closed position. In either of these positions hydraulic fluid may pass freely between ports 100 and 102 and 100' and 102 depending solely upon pressure differentials as grooves 223 and 223 always maintain this channel in an open condition. In the fully opened position port 101 is connected to port 103 by channel 235, groove 221 and channel 240.
- ports 100, 101, 102, and 103 may be in communication with each other through groove 212, cross drill 211, the bored passage 209 and the upper cross drill 210.
- cross drill 210 approaches groove 220 and passage 230 and continued downward motion of the spool 203 will place cross drill 210 in juxtaposition with passage 230.
- the gradual opening and closing of this cross drill 210 from the passage 230 constitutes a variable orifice or variable restrictor means.
- the variable orifice formed by the cross drill 210 and groove 220 cooperates through passage 230 and fixed resistor 231 of check valve 251 to form the bleeder unit or bleeder means. A unique capability of this bleeder unit will be described in the disclosure relating to the mode of operation.
- a check and relief value means 300 is interposed between port 103 and groove 222 of the valve housing.
- the check valve 301 comprises a collar 302 fixed within orifice 103 and operating on a spring 303 which urges directional poppet 304 into a position closing off channel or passage 240.
- the end section of poppet 304 is of a reduced diameter and isfurther provided with cross drill 306 which permits hydraulic fluid flowing from the upper end of hydraulic motor 20 to pass through a passage 341 to relief valve 310.
- Relief valve 310 comprises a threaded bolt 311 which serves as a seat for spring 313 which in turn urges valve 314 towards its seated position.
- the valve seat 315 is cupshaped in form and has an orifice 316 through its bottom portion.
- a cylindrical guide element 320 is interposed between the spring and the valve ball and acts as a guide in urging the valve towards its seat.
- a passageway 317 conducts fluid from the relief valve to channel 240.
- FIG. 9 discloses the subject matter of this invention operating on a trunnion block T in which the piston rods 21, 21' are transversely spaced for obtaining the rotational movement with respect to support stand S.
- the backhoe would be attached to the trunnion block.
- This invention may easily be adapted to operating in such manner although minor modifications and the dimensions of the sequence valves may have to be recalculated and modified somewhat with reference to simple geometry.
- FIG. 10 discloses the utilization of the subject matter of this invention in an articulated vehicle 400.
- the vehicle 400 may have two frame members 401 and 402 pivotable about a common axis 403.
- the hydraulic motors are then interconnected between frame members 402 and 401 by appropriate pin connections 420, 420, 421 and 421.
- the hydraulic system of the articulated vehicle may be utilized to provide power for the subject matter of our invention and conventional flow control valves may be used therewith to control the action of the hydraulic motors 20, 20'.
- each motor operates on the swing mount 10 through a lever arm L or L which are continually changing in dimension.
- L has its maximum dimension while in stage 2, (60 120 of rotation) neither L nor L is maximized while in stage 3 (120 168 of rotation) L has its maximum dimension.
- Stage 4 represents the functioning of the bleeder means during the last few degrees of rotation.
- FIGS. 4 through 8 for a discussion of the mode of operation of the system.
- Hydraulic fluid is then directed through branch conduits 60 and 61' to ports 100 and 101.
- the fluid under pressure is then directed through the valve housing 201, groove 223 and out port 102 through conduit 64 to port 104 and acts against the rear face of piston 23, thus driving the rod 21- forward.
- the hydraulic'fluid in conduit 61 enters port 101 of sequence valve 200 and is blocked at that point by check valve 251 and spool 203 closing the passage 235 since sequence valve 200 is in its fully closed position.
- both rods 21 and 21 must extend to pivot the support bracket about its pivot point which is flange connection 1313 (See FIG. 1). As rod 21 extends fluid must be drawn into chamber C so as to flll a void.
- the fluid in chamber C is now being directed to the sump through the one-way restrictor 119', port 104, conduit 64, and around the spool 203'.
- the torque begins to increase at 60 degrees; the angular velocity of the swing mount 10 must decrease, and the one-way valve 119 will cause the fluid in chamber C to resist any tendency of the boom structure to run away, thus preventing cavitation.
- check and relief valve 310 which resist flow from chamber B provides additional resistance to prevent cavitation.
- chambers A, B, and D are still subject to system pressure with chamber C being directed to sump through oneway restrictor 119 in port 104.
- the energy load which must be absorbed is the kinetic energy of the swinging mass as well as input energy of the supply fluid.
- the pressure in chambers A and C initially represent resistance to torque generated by the supply fluid since displacement of fluid from these chambers is opposed by the one-way resistors I19 and 119 and chamber A is exposed to system pressure.
- the bleeder unit is most effective in reducing the input energy, thus reducing the quantity of total energy. required to be absorbed by the cushioning action within chamber C. Consequently, as deceleration is initiated, the spool 203 of sequence valve 200 is moving towards its fully closed position and all ports of valve 200 will be interconnected. As cross drill 210 approaches conduit 230, the input energy is increasingly exhausted through conduit 62 to sump.
- the variable orifice should preferably have such dimensions as will permit the input energy to be increasingly diminished but yet maintain sufficient energy in the system to provide an acceptable velocity potential for continued swing of the backhoe even though it has been stopped.
- variable orifice comprising cross drill 210 approaching conduit 230 may begin to open at 168 of swing movement, and deceleration resulting from cushion ring 27' may occur at 177.
- the bleeder means 250 bleeds no flow at 168 and just less than full flow at 183 at system pressure the following observations may be made:
- deceleration begins and input flow will be increasingly exhausted to the sump.
- chamber C will create negative torque so as to absorb the larger portion of the KE, and the supply line pressure will increase, any pressure surge being minimized by bleeder 250.
- the bleeder 250 being properly proportioned permits such movement.
- the variable orifice will bleed off only 6 GPM at system pressure, a maximum velocity potential of 3 GPM at system pressure will be available to develop torque and continue rotation.
- This velocity potential may also be referred to as the pep" within the system at the extreme limits of rotational movement. ln other words the operator of the backhoe is able to obtain good deceleration characteristics and excellent response to continued rotational movement after bringing the support bracket 10 to zero angular velocity in the vicinity of 168 to 183.
- the bleeder unit performs 4 unique functions in that it:
- bleeder means herein depicted comprises a variable orifice in series with a fixed orifice
- the applicants also clearly consider flow sensitive devices as substitutes therefor. For example a spool valve operative upon a certain pressure differential might be interposed between the sequence valve and the hydraulic motors with the pressure differential being measured across a fixed orifice.
- a pressure from the input conduit upon a preset flow through the orifice into the actuating motor, a pressure from the input conduit.
- a backhoe having a support stand attached to a tractor, a swing support bracket pivotally connected to said support stand and supporting a boom, dipper stick and shovel of the backhoe with hydraulic motors for operation thereof, the improvement comprising:
- directional flow control means operably connected to said conduit means for selectively delivering fluid pressure to the hydraulic motors whereby rectilinear expansion and contraction of the motors create rotational movement of the swing support member about its pivotal axis on the support stand, and
- sequence valve means are interposed in said conduit means between the directional flow control means and the hydraulic motors for sensing the position of the hydraulic motors as they rotate the support bracket about its pivotal connections and for directing fluid pressure sequentially first to the head end of one motor only, then to both the cylinder end of said one motor and the rod end of the other motor, and then to both ends of said one motor and to the rod end of said other motor.
- a spool connected to each of said hydraulic motors and disposed within said valve housings for reciprocal movement therein, said spool and said valve housing cooperative for controlling torque output delivered to the swing support member by directing flow to hydraulic motors in proper sequence.
- bleeder valve means are interposed between said sequence valve means and said directional flow control means for reducing fluid flow delivered to the hydraulic motors as the swing support bracket approaches the limit of its rotation.
- hydraulic circuit means including a source of fluid energy connected to each motor by conduit means leading from said tractor hydraulic system
- directional flow control means operably connected to said hydraulic circuit for selectively delivering fluid energy to the hydraulic motors
- sequence valve means interposed in said hydraulic circuit between said directional flow control means and said hydraulic rams for sensing the position of said swing support bracket and for directing fluid energy to appropriate ends of said hydraulic rams either independently or simultaneously so as to maintain a more constant effective moment arm so as to provide relatively constant torque output on the swing member.
- check and relief valve means for opposing the exhaust fluid from the appropriate ends of said hydraulic motors so as to maintain said torque output more constant.
- fluid circuit means connected to said motorsfor delivering fluid energy thereto and including sequencing valves directing said energy sequentially first to one end of one motor only, then to both said one end and to the other end of the other motor and then to both ends of said one motor and to said other end of said other motor.
- a. exhaust limiting means are associated with said circuit means for controlling the torque delivered to said swing support bracket.
- a. exhaust limiting means are associated with said motors for controlling velocity of said swing assembly.
- a backhoe having a support stand attached to a tractor, a swing support bracket pivotally connected to said support stand about a vertical axis and supporting earth working equipment for rotational movement, the improvement comprising:
- said interconnection between the swing support bracket and said hydraulic motor means being on a vertical axis parallel to and displaced from the vertical axis connecting the swing support bracket and the support stand such that upon extension and retraction of the hydraulic motor means, the force applied to said swing support bracket by said motors is applied through a variable dimension lever arm, and
- fluid circuit means interconnected to said motors for delivering fluid energy thereto and including sequencing valves for directing said energy sequentially first to one motor and then to both motors so as to maintain the torque delivered to said swing support bracket more constant as the lever arm changes in response to rotational movement.
- a backhoe having a support stand attached to a tractor, a swing support bracket pivotally connected to said support stand and supporting earth working equipment for rotational movement, the improvement comprising:
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- Operation Control Of Excavators (AREA)
Abstract
Description
Claims (12)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US00123460A US3815766A (en) | 1970-05-04 | 1971-03-11 | Backhoe swing mechanism |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US3422770A | 1970-05-04 | 1970-05-04 | |
US00123460A US3815766A (en) | 1970-05-04 | 1971-03-11 | Backhoe swing mechanism |
Publications (1)
Publication Number | Publication Date |
---|---|
US3815766A true US3815766A (en) | 1974-06-11 |
Family
ID=26710705
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00123460A Expired - Lifetime US3815766A (en) | 1970-05-04 | 1971-03-11 | Backhoe swing mechanism |
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Country | Link |
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US (1) | US3815766A (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4201509A (en) * | 1978-10-04 | 1980-05-06 | Ford Motor Company | Backhoe swing cylinder hydraulic circuit |
US4457656A (en) * | 1981-01-30 | 1984-07-03 | Nolan Systems, Inc. | Stack assembling apparatus and technique |
US6422804B1 (en) * | 2000-02-18 | 2002-07-23 | Deere & Company | Inertia load dampening hydraulic system |
US6474064B1 (en) | 2000-09-14 | 2002-11-05 | Case Corporation | Hydraulic system and method for regulating pressure equalization to suppress oscillation in heavy equipment |
US6647721B2 (en) * | 2001-11-07 | 2003-11-18 | Case, Llc | Hydraulic system for suppressing oscillation in heavy equipment |
US20030230010A1 (en) * | 2001-09-25 | 2003-12-18 | Eric Sharkness | Hydraulic swing damping system |
US6666125B2 (en) | 2002-03-14 | 2003-12-23 | Sauer-Danfoss Inc. | Swing cylinder oscillation control circuit and valve for oscillating booms |
US20120305280A1 (en) * | 2010-04-01 | 2012-12-06 | Oestling Thomas | Rock Drilling Machine And Use Thereof For Hindering Occurrence And Spreading Of Cavitation Bubbles |
US20160258451A1 (en) * | 2015-03-05 | 2016-09-08 | Paul S. Anderson | Hydraulic Cylinder Drive System |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2528985A (en) * | 1947-01-22 | 1950-11-07 | Wunsch Harry | Hydraulically actuated swing boom crane |
US2766730A (en) * | 1953-11-02 | 1956-10-16 | Edwards Miles Lowell | Condition responsive pneumatic control system |
US3047171A (en) * | 1959-10-12 | 1962-07-31 | Case Co J I | Swing mechanism for backhoe |
US3395812A (en) * | 1966-03-21 | 1968-08-06 | Wain Roy Corp | Boom swing system |
US3430503A (en) * | 1967-03-30 | 1969-03-04 | Ford Motor Co | Backhoe swing mechanism |
US3452882A (en) * | 1968-03-18 | 1969-07-01 | Massey Ferguson Inc | Swing mechanism for backhoes |
US3680723A (en) * | 1971-02-18 | 1972-08-01 | Case Co J I | Hydraulic control system for backhoes |
-
1971
- 1971-03-11 US US00123460A patent/US3815766A/en not_active Expired - Lifetime
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2528985A (en) * | 1947-01-22 | 1950-11-07 | Wunsch Harry | Hydraulically actuated swing boom crane |
US2766730A (en) * | 1953-11-02 | 1956-10-16 | Edwards Miles Lowell | Condition responsive pneumatic control system |
US3047171A (en) * | 1959-10-12 | 1962-07-31 | Case Co J I | Swing mechanism for backhoe |
US3395812A (en) * | 1966-03-21 | 1968-08-06 | Wain Roy Corp | Boom swing system |
US3430503A (en) * | 1967-03-30 | 1969-03-04 | Ford Motor Co | Backhoe swing mechanism |
US3452882A (en) * | 1968-03-18 | 1969-07-01 | Massey Ferguson Inc | Swing mechanism for backhoes |
US3680723A (en) * | 1971-02-18 | 1972-08-01 | Case Co J I | Hydraulic control system for backhoes |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4201509A (en) * | 1978-10-04 | 1980-05-06 | Ford Motor Company | Backhoe swing cylinder hydraulic circuit |
US4457656A (en) * | 1981-01-30 | 1984-07-03 | Nolan Systems, Inc. | Stack assembling apparatus and technique |
US6422804B1 (en) * | 2000-02-18 | 2002-07-23 | Deere & Company | Inertia load dampening hydraulic system |
US6474064B1 (en) | 2000-09-14 | 2002-11-05 | Case Corporation | Hydraulic system and method for regulating pressure equalization to suppress oscillation in heavy equipment |
US7032332B2 (en) | 2001-09-25 | 2006-04-25 | Cnh America Llc | Method of controlling a backhoe |
US20030230010A1 (en) * | 2001-09-25 | 2003-12-18 | Eric Sharkness | Hydraulic swing damping system |
US6886278B2 (en) | 2001-09-25 | 2005-05-03 | Cnh America Llc | Hydraulic swing damping system |
US6647721B2 (en) * | 2001-11-07 | 2003-11-18 | Case, Llc | Hydraulic system for suppressing oscillation in heavy equipment |
US6666125B2 (en) | 2002-03-14 | 2003-12-23 | Sauer-Danfoss Inc. | Swing cylinder oscillation control circuit and valve for oscillating booms |
US20120305280A1 (en) * | 2010-04-01 | 2012-12-06 | Oestling Thomas | Rock Drilling Machine And Use Thereof For Hindering Occurrence And Spreading Of Cavitation Bubbles |
US10184294B2 (en) * | 2010-04-01 | 2019-01-22 | Epiroc Rock Drills Aktiebolag | Rock drilling machine and use thereof for hindering occurrence and spreading of cavitation bubbles |
US20160258451A1 (en) * | 2015-03-05 | 2016-09-08 | Paul S. Anderson | Hydraulic Cylinder Drive System |
US9835182B2 (en) * | 2015-03-05 | 2017-12-05 | Paul S. Anderson | Hydraulic cylinder drive system |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: DRESSER INDUSTRIES, INC., A CORP. OF DEL. Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:INTERNATIONAL HARVESTER COMPANY;REEL/FRAME:004130/0646 Effective date: 19821101 Owner name: DRESSER INDUSTRIES, INC., A CORP. OF DEL., STATELE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:INTERNATIONAL HARVESTER COMPANY;REEL/FRAME:004130/0646 Effective date: 19821101 |
|
AS | Assignment |
Owner name: DRESSER FINANCE CORPORATION, DALLAS, TX., A DE COR Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:DRESSER INDUSTRIES, INC.;REEL/FRAME:004994/0061 Effective date: 19880831 Owner name: KOMATSU DRESSER COMPANY, E. SUNNYSIDE 7TH ST., LIB Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:DRESSER FINANCE CORPORATION, A CORP. OF DE.;REEL/FRAME:004994/0077 Effective date: 19880901 |