US3460278A - Control for a dragline - Google Patents

Control for a dragline Download PDF

Info

Publication number
US3460278A
US3460278A US499348A US3460278DA US3460278A US 3460278 A US3460278 A US 3460278A US 499348 A US499348 A US 499348A US 3460278D A US3460278D A US 3460278DA US 3460278 A US3460278 A US 3460278A
Authority
US
United States
Prior art keywords
signal
bucket
reel
proportional
signals
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
US499348A
Other languages
English (en)
Inventor
Joseph A Pesavento
Darl C Washburn Jr
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.)
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric 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 Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Application granted granted Critical
Publication of US3460278A publication Critical patent/US3460278A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/46—Dredgers; Soil-shifting machines mechanically-driven with reciprocating digging or scraping elements moved by cables or hoisting ropes ; Drives or control devices therefor
    • E02F3/48—Drag-lines

Definitions

  • This invention relates to a semi-automatic control system for a dragline, and more particularly to a control system of the type described in which hoist (up and down) and drag (in and out) directional signals for the dragline are obtained from a single master controller with two courses of movement at an angle to each other, for example around intersecting axes.
  • a dragline includes a bucket suspended from an inclined boom by means of a cable, the bucket 'being designed such that when it is pulled toward the base of the boom by a second cable, it will scrape soil or other material from the surface being excavated.
  • the aforesaid first and second cables are normally wound upon motordriven reels such that rotation of the respective reels in one direction or the other will determine the position of the bucket and its direction of movement.
  • the present invention seeks to provide a new and improved system for operating a dragline, which system eliminates much of the physical coordination and skill required of the operator by prior-art control systems for such equipment.
  • an object of the invention is to pro vide a control for a dragline in which the hoist and drag directional signals for the dragline bucket are derived from a single master switch having two courses of movement.
  • the operator simply has a single lever which he can move toward and away from himself and also up or down.
  • the lever is 3,460,278 Patented Aug. 12, 1969 mounted on what can be compared to a ball and socket joint.
  • the operator In order to pull the bucket toward the base of the boom along a horizontal path, the operator simply pulls the levertoward himself. Conversely, to move the bucket away from the base of the boom along a horizontal axis, he will simply push the lever away from himself.
  • Up and down movement of the backet is controlled by moving the lever up or down, as the case may be.
  • the control system is such that for any position of the control lever, the reels on which the cables are wound are automatically rotated in one direction or the other to position the bucket as demanded by the control lever.
  • Another object of the invention is to provide a control system of the type described above in which movement of the two course control lever produces signals which are proportional to the desired velocity components of the dragline bucket. In this way, the further the operator moves the control lever from its central or null position, the faster will be the velocity of the bucket in the desired direction.
  • a dragline including a housing 10 mounted for pivotal movement on a base or tub 12, and adapted to move over the ground by means of crank-driven shoes 14.
  • a first cable 20 is wound upon a reel 22 in housing 10; passes around pulley 17 mounted on housing 10 and pulley 18, and is connected to the top of the dragline bucket 24.
  • a second cable 26 is wound upon reel 28 in housing 10 and is connected, as shown, to the forward upper edge of the dragline bucket 24.
  • Reel 22 is connected to a reversible hoist drive motor 34 through mechanical gearing schematically represented in the drawing by broken line 36.
  • the reel 28 is connected to drag drive motor 30 through mechanical gearing represented by broken line 32.
  • the motors 34 and 30 are controlled by suitable motor control circuits 38 and 40, respectively.
  • B Length of boom 16 between point 0, O and point R Length of cable 20 between point x and point x, y (i.e., length proportional to active cable removed from hoist drum 22).
  • R Length of cable 26 between point x, y and point 0, O (i.e., length proportional to active cable removed from drum 28).
  • command signals R and R for driving motors 30 and 34 and, hence, reels 22 and 28 can be derived, assuming that the angles ,0 and t can also be determined.
  • Circuitry for accomplishing the foregoing includes a rheostat 46 connected through gear reducer 47 (represented by broken line) to drum 22 for producing a first alternating current electrical signal on lead 48 proportional in magnitude to the length, R of cable 20 between points x, y and x 35;.
  • a second rheostat 42 is connected through gear reducer 43 (represented by broken line) to reel 28 and is adapted to produce an alternating current electrical signal on lead 44 proportional in magnitude to the length, R of cable 26 between point 0, O and point x, y.
  • An alternating current signal generator 50 is arranged to produce a signal on lead 52 which is proportional in magnitude to the distance, B between points 0, O and x 31 this signal being of constant magnitude.
  • the signal proportional to B on lead 52 is applied through a first squaring multiplier 54, the output of multiplier 54 being inverted in inverter 56'to produce the signal -B
  • the signal proportional to R on lead 48 and the signal proportional to R on lead 44 are passed through squaring multipliers 58 and 69, respectively.
  • the signal at the output of multiplier 58, is, therefore, R
  • the signal at the output of multiplier 60 is inverted in inverter 62 to produce the signal -R
  • the signals --B R and R are applied to an operational amplifier 64 which adds them to produce an electrical quantity equal to R B R Reverting again to Equation I given above, it can be written as:
  • the inputs R B and R comprise one-half of the equation given above. Therefore, if a fourth input comprising 2BR cos 6 is applied to the fourth input lead 66 for the operational amplifier 64, all of the input signals will balance each other and the output of the operational amplifier 64 on lead 68 will be zero.
  • the output from the operational am lifier 64 is applied to a servomotor 70 which will be caused to rotate in one direction or the other, depending upon the output signal on lead 68.
  • the servomotor 70 rotates the rotor of a resolver, generally indicated by the reference numeral 72.
  • Resolver 72 may, for example, be of the type manufactured by the Ford instrument Company, Long Island City, N.Y. and includes a pair of windings 74 and 76 wound at right angles to each other on a rotor element connected through linkage 78 to the servomotor 70.
  • One or more stator windings are included in the resolver 72, only one winding 30 being utilized in the present instance.
  • the basic operation of a resolver is exemplified by its computation of the sine and cosine of an angle.
  • the stator winding 80 is supplied with a variable alternating current voltage proportional to ZBR In the present case this voltage, proportional to ZBR s derived by multiplying the signal proportional to B by the signal proportional to R in multiplier 82 to roduce an output signal proportional to BR
  • Two signals proportional to BR are summed in adder 84 to produce the signal ZBR
  • the shaft 78 is turned to represent a particular angle, and the two rotor windings 74 and 76 provide output voltages that are proportional to the product of the signal applied to stator winding 80 times the sine and cosine of the angle to which the shaft 78 was turned.
  • the shaft 78 of servomotor 70 is also connected to one gear 86 of a mechanical differential device 88.
  • the differential device 88 includes two beveled gears 90 and 92 rotatable about shafts which are at right angles with respect to the shaft 78.
  • the gear 92 is connected to a dial 94 which is adjusted for the angle 0, this angle being fixed since the position of the boom 16 is fixed with respect to horizontal.
  • the operation of the differential device 88 is such that the degrees of rotation of bevel gear 90 will be equal to the degrees of rotation of gear 86 minus the degrees of rotation effected by the dial 94. Since the angular position of shaft 78 is equal to 0 and since 0 is equal to given above, it will be appreciated that subtraction of from +ip gives the angle 1p.
  • angular rotation of gear 90 is equal to b; and since the gear 90 is connected to the rotor of a second resolver 96 through coupling 98, the rotation of the rotor of resolver 96 will be a number of degrees equal to 0.
  • the rotor of resolver 96 again includes two windings 100 and 102 at right angles to each other, only the winding 102 being utilized in the present instance. In this case, however, the two stator windings 104 and 106 are energized by signals ab and respectively. The manner in which at and y are derived will be described hereinafter.
  • the output on rotor winding 102 will be equal to the magnitude of the input signal on one stator times the cosine of the angle representing the angular position of the rotor, plus the magnitude of the other input signal times the sine of the angle.
  • the signals X and y are derived from a two-axis master controller, under the control of the operator, and identified generally by the reference numeral 108. It includes a generally horizontal handle 110 (shown vertical in the drawing for purposes of explanation) secured to a shaft 112 mounted for rotation on a ring member 114. The ring member 114, in turn, is mounted for rotation on shafts 116 and 118. In this manner, up and down move ment of the handle 110 will cause the shaft 112 to rotate; while movement of the handle forward (out) or reverse (in) will cause shafts 116 and 118 to rotate.
  • the shaft 112 is connected to the wiper brush of a rheostat 120 having its opposite ends connected to a source of alternating current voltage 121.
  • a center tap on the rheostat 120 is grounded, as shown.
  • the signal R increases at the input to control circuit 38 in a manner hereinafter described to cause the circuit 38 to rotate motor 34 in one direction; whereas when the handle 110 is moved downwardly, the phase of the signal R is reversed in phase such that it causes the control circuit 38 to rotate motor 34 in the other direction.
  • the speed of motor 34 is determined by the magnitude of the signal R derived from winding 102. Consequently, the speed of the bucket 24, up or down, will be dependent upon the amount of movement of handle 110 up or down from its center position. For instance, if the operator Wishes to move the bucket 24' upwardly at a faster rate, he will simply push the handle 110 upwardly to a further extent from its center position.
  • up or down movement of the bucket is determined by the phase of the signal R which phase is determined by the position of the center tap of rheostat 120 on either side of its grounded center point.
  • a direct current directional output in the motor control circuit 38 is derived from the alternating current signal R in accordance with conventional techniques through the use of a phase detecting AC/DC transistor chopper demodulator, filter and amplifier, not shown, to produce a plus or minus 20 watt direct current signal of about 40 milliamperes.
  • Movement of bucket 24 along the x-axis is affected in a somewhat similar manner. That is, the shaft of master controller 108 is connected to the wiper brush of a second rheostat 126 energized by source 127 and having a grounded center tap. In this manner, forward (out) or backward (in) movement of the handle 110 will cause the alternating current voltage applied to winding 104 to change in magnitude, the further the handle 110 is moved fromv its center position, the greater the magnitude of the alternating current signal. Furthermore, when the center tap of rheostat 126 is on one side of the grounded center tap, the signal applied to winding 104 will be 180 out of phase with respect to that when the Wiper brush is on the other side of the center tap.
  • the signal on winding 102 will be equal to the magnitude of the signal (ab cos 0+1] sin 1,11). In accordance with Equation VI given above, this is equal to the desired control signal R for motor control circuit 40. Assuming that the control handle 110 is in its center position as shown, the output signal R will be zero and the motor 30 and reel 28 will be stationary. When, however, the handle 110 is pulled in reverse, for example, a signal will be produced on winding 102 of resolver 96 to cause the motor 30 and reel 28 to rotate in a clockwise direction, thereby causing the bucket 24 to move toward the housing 10'.
  • the control circuitry for motor 34 is similar and includes a squaring multiplier 132 which produces an output applied through inverter 134 to produce the signal B
  • the signal R is applied through squaring multiplier 136 and inverter 138 to produce the signal R
  • the signal R is applied through squaring multiplier 140 to produce the signal R and the three signals R R -B are applied to an operational amplifier 142 along with a fourth signal derived from a rotor winding 144 on resolver 145.
  • the signals R R and B could be derived from multipliers 54, 58 and 60; however, separate multipliers are shown herein for purposes of illustration.
  • the stator Winding 146 of resolver has applied thereto a signal proportional to ZBR as is derived from multiplier 148 and adder 150 in the manner described above in connection with circuits 82 and 84.
  • the signal on lead 152 from rotor winding 144 will be proportional to ZBR cos 0 to satisfy Equation II given above.
  • the output of the operational amplifier 142 is applied to a servomotor 154 similar to servomotor 70 described above.
  • the shaft 156 of servomotor 154 is connected to the rotor of resolver 145 and also to a first bevel gear 158 of a second differential 160.
  • Gear 162 of differential is connected to a dial 164 which, in this case, is rotated to an angle corresponding to 0 this angle being that between vertical and the dimension B, and is fixed for a particular operating condition of the dragline due to the fact that the position of the boom 16 is fixed.
  • control signals R and R will be produced to rotate reels 28 and 22 so as to manipulate the bucket 24 as desired by the operator.
  • the speed at which the bucket 24 moves along the x and y axes is, as mentioned above, determined by the amount of movement of the handle 110 from its center position forward or reverse and up or down. Thus, in order to move the bucket 24 faster, the operator will simply move the handle 110 further from its center position in either plane.
  • a control system for material handling apparatus in which a material handling device is suspended from a boom by a cable wound upon a first reversible motordriven reel and wherein the device is pulled toward the base of the boom by a cable wound upon a second reversible motor-driven reel;
  • the improvement comprising a single master controller movable along a first course and along a second course at an angle to the first course for controlling vertical and horizontal movement of the device respectively, means for producing a first electrical signal which varies as a function of the position of the controller along said first course, means for producing a second electrical signal which varies as a function of the position of the controller along the second course, and circuitry connected to said controller and responsive to said first and second signals for controlling said motordriven reels and the position of said device, said circuitry including a first servo system for controlling one of said motor-driven reels and a second servo system for con trolling the other of said motor-driven reels, each of said servo systems incorporating a mechanical differential device including a plurality
  • a material handling device is suspended from a boom by a first cable wound upon a first reversible motordriven reel and wherein said device is pulled toward the base of the boom by a second cable wound upon a second reversible motor-driven reel;
  • means for developing electrical signals B, R and R which are proportional to the lengths of the sides of the triangle defined by said boom and the active lengths of said first and second cables, means for producing an electrical signal proportional to ZBR means including apparatus responsive to the electrical signals proportional to R R B and ZBR for developing an electrical signal R for controlling the rotation of said first reel in acccordance with the equation:
  • means for developing an electrical signal proportional to ZBR means including apparatus responsive to the electrical signals proportional to R R E and ZBR for developing an electrical signal R for controlling rotation of said second reel in accordance with the' equation:
  • a material handling device is suspended from a boom by a first cable wound upon a first reversible motordriven reel and wherein said device is pulled toward the base of the boom by a second cable wound upon a second reversible motor-driven reel; the improvement of means for generating three electrical signals proportional to B R and R wherein B, R and R are proportional in magnitude to the lengths of the sides of the triangle defined by said boom and the active lengths of said first and second cables, means for producing an electrical signal proportional to 2BR cos where 6 is the angle between the boom and the active length of said second cable, means including apparatus responsive to the signal proportional to R R B and ZBR cos 0 for controlling rotation of said second motor-driven reel, means for producing an electrical signal proportional to ZBR cos 0 where 0 is the angle between said boom and the active length of said first cable, and means including apparatus responsive to the signals proportional to R R B and 2BR cos 0 for controlling rotation of said first motordriven reel.
  • a control system for material handling apparatus in which a material handling device is suspended from a boom by a first cable wound upon a first reversible motordriven reel and wherein said device is pulled toward the base of the boom by a second cable wound upon a second reversible motor-driven reel; the improvement comprising a single master controller movable along a first course and along a second course at an angle to the first course for controlling combined vertical and horizontal movement of said device, means for producing a first signal which varies as a function of the position of the controller along said first course, means for producing a second signal which varies as a function of the position of the controller along the second course, said first and second signals being proportional to the vertical and horizontal components respectively of a desired resultant velocity for said device, circuit means coupled to said master controller for converting said first and second signals to a third signal proportional to that component of said desired resultant velocity which is in line with the first cable, circuit means coupled to said master controller for converting said first and second signals to a fourth signal proportional to that component of

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Control Of Multiple Motors (AREA)
  • Control And Safety Of Cranes (AREA)
US499348A 1965-10-21 1965-10-21 Control for a dragline Expired - Lifetime US3460278A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US49934865A 1965-10-21 1965-10-21

Publications (1)

Publication Number Publication Date
US3460278A true US3460278A (en) 1969-08-12

Family

ID=23984924

Family Applications (1)

Application Number Title Priority Date Filing Date
US499348A Expired - Lifetime US3460278A (en) 1965-10-21 1965-10-21 Control for a dragline

Country Status (2)

Country Link
US (1) US3460278A (enrdf_load_stackoverflow)
JP (1) JPS4812562B1 (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3851749A (en) * 1972-05-23 1974-12-03 L Vidal Drag lines for concrete
US3934126A (en) * 1973-12-28 1976-01-20 Oleg Alexandrovich Zalesov Control device for a dragline excavator
US4035621A (en) * 1973-12-03 1977-07-12 General Electric Company Excavator data logging system
US4542600A (en) * 1984-11-06 1985-09-24 Mobil Oil Corporation Method for controlling the depth of dragline excavating operations
US4684854A (en) * 1986-06-16 1987-08-04 Dresser Industries, Inc. Method and apparatus for adding additional D.C. motors and control thereof
US4743814A (en) * 1987-02-06 1988-05-10 Sankey Edwin W Static power conversion for adding DC motors
US6140787A (en) * 1997-07-23 2000-10-31 Rsi Technologies Ltd. Method and apparatus for controlling a work implement

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2633649A (en) * 1947-02-28 1953-04-07 Page Engineering Company Dragline bucket and boom control
US2978820A (en) * 1957-11-13 1961-04-11 American Hoist & Derrick Co Drag line crane
US3084805A (en) * 1961-08-24 1963-04-09 Robert B Mckinnon Control device for cranes
US3144146A (en) * 1960-11-17 1964-08-11 Westinghouse Electric Corp Mimic positioning controller

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2633649A (en) * 1947-02-28 1953-04-07 Page Engineering Company Dragline bucket and boom control
US2978820A (en) * 1957-11-13 1961-04-11 American Hoist & Derrick Co Drag line crane
US3144146A (en) * 1960-11-17 1964-08-11 Westinghouse Electric Corp Mimic positioning controller
US3084805A (en) * 1961-08-24 1963-04-09 Robert B Mckinnon Control device for cranes

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3851749A (en) * 1972-05-23 1974-12-03 L Vidal Drag lines for concrete
US4035621A (en) * 1973-12-03 1977-07-12 General Electric Company Excavator data logging system
US3934126A (en) * 1973-12-28 1976-01-20 Oleg Alexandrovich Zalesov Control device for a dragline excavator
US4542600A (en) * 1984-11-06 1985-09-24 Mobil Oil Corporation Method for controlling the depth of dragline excavating operations
US4684854A (en) * 1986-06-16 1987-08-04 Dresser Industries, Inc. Method and apparatus for adding additional D.C. motors and control thereof
AU603359B2 (en) * 1986-06-16 1990-11-15 Dresser Industries Inc. Method and apparatus for adding additional D.C. motors and control thereof
US4743814A (en) * 1987-02-06 1988-05-10 Sankey Edwin W Static power conversion for adding DC motors
US6140787A (en) * 1997-07-23 2000-10-31 Rsi Technologies Ltd. Method and apparatus for controlling a work implement

Also Published As

Publication number Publication date
JPS4812562B1 (enrdf_load_stackoverflow) 1973-04-21

Similar Documents

Publication Publication Date Title
US2465624A (en) Computer device for solving trigonometric problems
US4351152A (en) Electronic constant speed control for a hydrostatic transmission
US3636325A (en) Analog-programmed control system for excavators having jibs
US3460278A (en) Control for a dragline
US3857078A (en) Actuating system
US3586184A (en) Control apparatus and method for an excavating shovel
US3058242A (en) Control system for earth moving machine
US3206663A (en) Machine tool position control servomechanism with positioning rate control
US3283230A (en) Momentum compensation in control means for electrical positioning means
US3500150A (en) Tool radius offset control for a closed loop multiaxes numerical control system
US2417229A (en) Electric computer
US2486781A (en) Angle calculating apparatus for use with unstable platforms
US2796565A (en) Electrical control system
US3144146A (en) Mimic positioning controller
US3246129A (en) Cutter compensation system for automatic machine tool
SE7613820L (sv) Anordning vid servosystem med sluten servokrets.
US2406856A (en) Apparatus for controlling rotation
US4117385A (en) Tracer control circuit
JPS5952254B2 (ja) 油圧シヨベルの直線掘削自動運転装置
US2715497A (en) Electric integrating computer for radar trainer
US3178563A (en) Interpolating arrangements especially for the automatic control of machine tools
GB1093559A (en) Apparatus for generating a curve from digital data
US2859396A (en) Scanning system
US2788478A (en) Limit stop control circuit for syncro system
US3943764A (en) Sailboat steering indicator system