US3747886A - Load balancer with safety control - Google Patents

Load balancer with safety control Download PDF

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Publication number
US3747886A
US3747886A US00181906A US3747886DA US3747886A US 3747886 A US3747886 A US 3747886A US 00181906 A US00181906 A US 00181906A US 3747886D A US3747886D A US 3747886DA US 3747886 A US3747886 A US 3747886A
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United States
Prior art keywords
cylinder
arm
air
load
flow
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Expired - Lifetime
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US00181906A
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English (en)
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A Carlson
R Watson
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ConocoPhillips Co
Interlake Cos Inc
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Individual
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Assigned to CONCO-TELLUS INC. reassignment CONCO-TELLUS INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: HEICO, INC.,
Assigned to INTERLAKE COMPANIES, INC., THE, A CORP. OF DE reassignment INTERLAKE COMPANIES, INC., THE, A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: CONCO-TELLUS INC.
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
    • B66C23/005—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes with balanced jib, e.g. pantograph arrangement, the jib being moved manually
    • 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
    • Y10S414/00—Material or article handling
    • Y10S414/13—Handlers utilizing parallel links

Definitions

  • ABSTRACT A load balancer having a load support arm with a power cylinder having a piston operably connected to the arm with a control circuit including a pilot operated valve for directing pressure fluid to the cylinder to maintain a constant pressure on the cylinder piston in all positions of the load support arm with means for limiting the rate of movement of said load support arm in the event that .either the load is lost or there is a loss of fluid pressure acting on said piston when there is a load on the load support arm.
  • a parallelogram arm system includes a load support arm and a piston and cylinder device connected to the parallelogram arm system.
  • a control circuit applies fluid pressure to the cylinder in an amount sufficient to balance the weight of the load in all positions of the para]- lelogram arm system, and safety controls make certain that there is no rapid rate of movement of the load sup port arm in the event that either the load is lost from the load support arm, which would result in rapid upward movement of the load support arm or there is a loss of fluid pressure acting on the cylinder which would result in a rapid rate of descent of the load support arm when carrying a load.
  • Load balancers are disclosed in prior patents owned by the assignee of this application.
  • Olsen US. Pat. N 0. 3,259,351 discloses a load balancer having the basic configuration of a parallelogram arm system.
  • a control circuit includes a pilot valve responsive to a control pressure and pressure in the cylinder acting on the parallelogram arm system for balancing a load in all positions of the parallelogram arm system.
  • This patent does not disclose any safety control for limiting movement of the parallelogram arm system when there is a loss of load nor a safety control which becomes operative when there is a loss of pressure fluid to limit the rate of descent of the load support arm of the parallelogram arm system.
  • Olsen US. Pat. No. 3,259,352 discloses a load balancer with a control circuit therefor, a safety control for controlling the rate of ascent of the load support arm thereof.
  • This safety control requires the use of a pressure piloted variable orifice valve.
  • the disclosures of the aforesaid Olsen patents in their disclosure of the parallelogram arm system and the connection of a piston and cylinder thereto are incorporated herein by reference.
  • This disclosure relates to an improved load balancer having safety controls limiting the rate of movement of the parallelogram arm system and the load support arm thereof in the event of possible, but improbable, conditions arising.
  • An object of this invention is to provide a new and improved load balancer with safety controls limiting the rate of rise of the load support arm thereof in the event that there is either a loss of load or the control circuit therefor is rendered operative when a load is not on the load support arm and for limiting the rate of descent of the load support arm whena load is carried thereon and there is a loss of pressure fluid for the load balancer.
  • Another object of the invention is to provide a load balancer as defined in the preceding paragraph wherein the structure for limiting the rate of rise of the load support arm in the event a load is lost from or not present on the load support arm includes a second fluid circuit connected to the power cylinder for the load balancer with the second fluid circuit having a reservoir, a fluid line extending between the reservoir and the power cylinder, and a velocity control valve in the line permitting free fluid flow from the reservoir to the power cylinder and restricting the flow from the power cylinder to the reservoir when the flow is above a predetermined rate.
  • Still another object of the invention is to provide a load balancer having a parallelogram arm system including a load support arm with a power cylinder having a piston connected thereto, a control circuit for maintaining a fluid pressure acting on the piston in the cylinder, and means for limiting the rate of descent of the load support arm in the event there is a loss of fluid pressure including a velocity control valve in a fluid exhaust passage of the control circuit with the velocity control valve having a normal position to permit normal fluid flow therethrough and movable to an airflow restricting position in response to a predetermined rate of flow therethrough whereby the rate of flow from the power cylinder is limited to a value sufficient to prevent rapid downward movement of the load support arm but still permit movement thereof at a normal rate during normal operation of the load balancer.
  • FIG. 1 is a side elevation of the load balancer
  • FIG. 2 is a schematic illustration of a fluid actuated balancer control circuit with the safety controls incorporated therein;
  • FIG. 3 is a vertical central section of a velocity control valve incorporated in a fluid line.
  • FIG. 4 is a fragmentary section of the pilot operated valve of the primary control circuit and showing a velocity control valve mounted therein and as a central section therethrough.
  • the load balancer is shown generally in FIG. 1 and includes a base member 10 which can be either a floor mounted pedestal or can be suspended from an overhead mount.
  • the base member 10 mounts a parallelogram arm system with a first arm 15 pivotally mounted to the base member 10 by a pivot-mounting 16.
  • a sec ond arm 20 is a load support arm and is pivoted to the first arm at a pivot pin mounting 21.
  • a third arm of the parallelogram system 22 is pivoted to load support arm 20 by a pivot connection 23 and a fourth arm 25 is pivotally connected at 26 and 27, respectively, to the first arm 15 and the third arm 22 to complete the parallelogram arm system.
  • the lower end of the load support arm 20 has means for supporting a load which in the form shown is a simple hook 30.
  • a counterweight 31 connected to an end of the first arm 15 balances the weight of the arms when not supporting a load and a power cylinder structure indicated generally at 35 is provided for balancing a load supported on the load support arm by means such as the hook 30.
  • the power cylinder 35 has a piston 36 (FIG. 2) with a piston rod 37 which connects to a plate 38 which is guided for up and down movement on the base member 10 by a pair of rollers 40 and 41 secured to the base member 10 and movable within a guide slot 42 in the plate 38.
  • the piston rod 37 is connected to the plate 38 by a pin 45.
  • the lower end of the cylinder is connected to a bracket 46 extending from the base member at a mounting 47.
  • the plate 38 has a generally horizontal slot 50 which receives a roller 51 connected to and defining the pivot 27 for interconnecting the third arm 22 and fourth arm 25 of the parallelogram system whereby the power cylinder acting on the plate 38 is operatively connected to the parallelogram system.
  • a roller 51 connected to and defining the pivot 27 for interconnecting the third arm 22 and fourth arm 25 of the parallelogram system whereby the power cylinder acting on the plate 38 is operatively connected to the parallelogram system.
  • As fluid under pressure is directed to the underside of the piston 36 to exert upward force on the piston rod 37, this force acts on the roller 51 to correspondingly change the relation of the parallelogram arm system with pivoting of the first arm about the pivot 16 to lift the load support arm 20.
  • the construction of the load balancer parallelogram arm system is shown more particularly in ONeill US. Pat. No. 3,402,911 owned by the assignee of this application.
  • the parallelogram arm structure is shown in more detail and it will be noted that there are a pair of the plates as plate 38 in this application in spaced apart relation with the connection of the piston rod 37 being intermediate the spaced apart plates.
  • the ONeill patent shows the power cylinder disposed above the parallelogram arm system with the load balancer depending from an overhead support. However, the function is the same in either arrangement of the power cylinder, that is, either above or below the parallelogram arm system.
  • a line 60 is connectable to a source of fluid under pressure such as a factory air line, and extends to a pilot operated valve indicated generally at 61 having two operating positions and a center closed position.
  • the valve is shown in the center closed position wherein the air supply line 60 is blocked and also an air exhaust line 62 leading from the valve is blocked.
  • This control box includes a pair of load, no-load toggle switches 66 and 67 and a pair of load adjustment regulators 68 and 69 in the form of pressure regulating valves. These components are in parallel between a line 70 branching from the air supply line 60 and a line 71 leading to an air pilot 72 for the pilot operated valve 61.
  • the pressure regulating valves 68 and 69 can be set to two different air pressures when the same two different weight loads are being handled repeatedly, and then the appropriate toggle switch 66 or 67 can be operated.
  • either of the pressure regulating valves 68 or 69 can be suitably adjusted. This adjustment is done visually since the in-- crease in pressure can be directed into the line 71 and pilot 7 2.
  • the pressure existing in line 63 is also directed to a pilot section 81 of the pilot operated valve 61 and when the pressure from cylinder 35 reaches a value equal to the pressure acting on pilot 72 there will be the same pressure on pilot 81 which will bring the pilot operated valve 61 back to the center closed position to maintain the parallelogram arm system in a desired position.
  • the previously known control circuit has been subject to safety problems.
  • One safety problem has arisen when a load is lost from the load support arm 20 as by falling off the hook 30. This causes a raising of the load support arm and of the piston 36 for a reduction of pressure in the lower part of the cylinder 35 which is a detection that the control valve 61 or pilot operated valve 61 should move upwardly with the result that additional air is supplied to the lower side of the cylinder which could cause a runaway condition.
  • the safety control provided under this condition also takes into account the possibility that the controls in control box 65 might be operated to supply pressure to the underside of the cylinder 35 when there is no load present on the load support arm 20. This would result in the same fast rate of ascent of the load support arm as when a load is lost from the arm.
  • the safety control includes a second fluid circuit including an oil reservoir provided with a removable cover 91 having an air vent 92 and a pair of baffle plates 93 extending into the reservoir and downwardly from the underside of the cover 91.
  • the reservoir is connected to the top side of the cylinder 35 and above the piston 36 by a line 94 which has a velocity control valve therein. This velocity control valve is located within the reservoir 90 and is shown in detail in FIG. 3.
  • the valve includes a spool locked to a land 101 within a section of the line 92 by an annular shoulder 102 and a snap-ring 103.
  • This valve spool has a central transverse wall 105 provided with a small opening 106 and with the wall of the valve spool having two circumferentially disposed rows of flow passage openings 107 and 108.
  • a movable sleeve 110 has a left-hand part thereof, as viewed in FIG. 3, surrounding a part of the spool 100 and is limited in its movement to the right by a snapring 111 positioned in a groove in a wall of the section of the line 94.
  • the sleeve 110 is urged to a normal position shown in FIG. 3 by a spring 112 acting between a spring retainer 115 abutted against the right-hand end of the spool 100 and an aperture effectively secured to the sleeve 110 by a snapring 117 fitted into a groove in the sleeve 110.
  • the disc 116 senses the rate of flow from right to left through the velocity control valve and when the force resulting from pressure drop thereacross exceeds the force of the spring 112 the sleeve 110 moves toward the left to a position indicated by a broken line 120 wherein the sleeve blocks the circumferential rows of openings108 whereby the only flow-through the valve is through the small opening 106 which limits the rate at which oil can be displaced from the upper side of the cylinder 35 and therefore limits the rate of movement of the piston 36 and the parallelogram arm system including the load support arm 20.
  • valve spring 112 will shift the sleeve 110 to the normal position shown in FIG. 3 whereby there can again be uncontrolled flow in either direction through the velocity control valve.
  • this velocity control valve there can be normal operation without any restriction caused by the velocity control valve, but the valve does limit the rate of flow of oil from the top of the cylinder to the reservoir to make certain that there is not a runaway rate of rise of the load balancer.
  • This safety control incorporates a velocity control valve, indicated in the schematic illustration of FIG. 2 at 130, mounted within the body of the pilot-operated valve 61. This is particularly shown in FIG. 4 wherein the body of thepilot-operated valve 61 has an air passage 131 and a chamber 132. A multi-apertured disc 133 is mounted in the chamber and is urged against a retention snap ring 134 by a spring 135 in the chamber and surrounding a part of the air passage .131. Flow from the pilot-operated valve 61 to exhaust is from right to left as viewed inFIG. 4 and in normal operation, the rate of flow is sufficiently small that the disc 133 remains in the position shown in FIG.
  • the spring returns thedisc 133 to position shown in FIG. 4, where it is held against the snap ring 134 and there is substantially free flow of air through the velocity control valve to permit normal adjustment movement of the load balancer under the urging of an opera- 101'.
  • a load balancer a frame, a load support arm movably mounted on said frame, a power cylinder having a piston movably connected to said arm to act against a load connected to said arm, means connectable to a source of fluid under pressure for applying fluid to said cylinder, a control circuit interposed be tween said means and said cylinder, said control circuit including a pilot operated valve for directing fluid to and from said cylinder, said valve being responsive to a control fluid pressure and cylinder fluid pressure whereby an imbalance in said fluid pressures causes said valve to restore 'a balance in said pressures, and safety control means for limiting the rate of movement of said load support arm in one direction in the event the load is removed from the load support arm and in the opposite direction in the event there is a loss of fluid under pressure, including a second fluid circuit connected to said cylinder and having a reservoir with a restricted rate of fluid flow from the cylinder to the reservoir.
  • a load balancer as defined in claim 1 wherein a line connects said cylinder and reservoir and a velocity control valve in said line permitting free fluid flow from the reservoir to said power cylinder and restricting the flow from the power cylinder to said reservoir when the flow is above a predetermined rate.
  • a load balancer comprising a base member, a generally horizontal first arm pivotally mounted to said base member for rotation about a horizontal axis; a generally vertical second arm adapted to receive a load to be hoisted and balanced by said assembly, said second arm being pivotally connected to one end of said first arm; a third arm pivotally connected to said second arm; and a fourth arm pivotally connected at one end to the other end of said first arm and at its other end to said third arm, said arms between said pivotal connections forming a parallelogram; and means for applying a generally vertical force to said third arm, said means comprising an air-actuated piston, a cylinder in which said piston is reciprocable, a pressure regulating circuit connected to said cylinder to maintain a constant pressure on the piston in all positions of said assembly, and means for limiting the rate of movement of said second arm in the event that either the load is lost or there is a loss of air pressure acting on said piston, including a fluid line connecting said reservoir to said cylinder to communicate'with the side of the piston opposite the air-actu
  • a load balancer a frame, a load support arm movably mounted on said frame, a power cylinder having a piston movably connected to said arm to act against a load connected to said arm, means connectable to a source of air under pressure for applying air to said cylinder, a control circuit interposed between said means and said cylinder, said control circuit including a pilot operated valve for directing air to and from said cylinder, said valve being responsive to a control air pressure and cylinder air pressure whereby an imbalance in said air pressure causes said valve to restore a balance in said pressures, an air exhaust passage from said pilot operated valve, and a velocity control valve in said exhaust passage having a normal position to permit normal air flow and movable to an air flow restricting position in response to a predetermined rate of flow therethrough, said velocity control valve including a body with an air passage and a chamber, a multiapertured disc movable in said chamber and having a diameter greater than the air passage, spring means urging said disc away from an end of said air passage and in a

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Hydraulic Control Valves For Brake Systems (AREA)
US00181906A 1971-09-20 1971-09-20 Load balancer with safety control Expired - Lifetime US3747886A (en)

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US18190671A 1971-09-20 1971-09-20

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US (1) US3747886A (en:Method)
JP (1) JPS5312663B2 (en:Method)
AU (1) AU465628B2 (en:Method)
CA (1) CA967455A (en:Method)
ES (1) ES406852A1 (en:Method)
FR (1) FR2158190B1 (en:Method)
GB (1) GB1359943A (en:Method)
IT (1) IT961405B (en:Method)
SE (1) SE395874B (en:Method)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3880393A (en) * 1973-06-04 1975-04-29 Conco Inc Load balancer with balance override control
US3883105A (en) * 1974-06-05 1975-05-13 Reizou Matsumoto Load handling equipment
US3917200A (en) * 1973-12-14 1975-11-04 Jay Johnson Pneumatic boom support for hand tools
US4421450A (en) * 1977-05-13 1983-12-20 Kono Toshio Cargo handling apparatus
US4659278A (en) * 1984-02-27 1987-04-21 Stahl Aufzuge & Co. KG Manipulator based on the pantograph principle
US4666364A (en) * 1984-06-19 1987-05-19 Stahl Aufzge Gmbh & Co. Kg Low friction cylinder for manipulators, based on the pantograph principle and equipped with a pneumatic balancer control
US6615710B1 (en) * 1999-11-30 2003-09-09 Ishigaki Company Limited Screw press apparatus
USD712945S1 (en) * 2013-08-01 2014-09-09 Vallon Gmbh Telescope-handling arm
US20240083720A1 (en) * 2021-03-19 2024-03-14 Staccato Technologies Ab Pneumatic load balancing system and method

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS585447Y2 (ja) * 1976-08-11 1983-01-29 ヤンマー農機株式会社 コンバインにおける刈取部上下用油圧作動装置
CN108297130B (zh) * 2018-01-10 2020-09-01 浙江大学 一种用于码垛机器人的减重方法
CN108408598B (zh) * 2018-03-15 2019-05-14 中国石油大学(华东) 一种水下气缸式动态平衡吊装作业装置

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2901219A (en) * 1957-04-04 1959-08-25 Gardner Denver Co Load balancer for hoists
US2939431A (en) * 1957-04-04 1960-06-07 Gardner Denver Co Load balancing device
GB1012460A (en) * 1963-02-07 1965-12-08 Jerry Kirsch Constant speed reciprocable hydro-pneumatic retarding device
US3259352A (en) * 1965-06-22 1966-07-05 Conco Engineering Works Inc Loading balancer assembly
US3307819A (en) * 1965-04-12 1967-03-07 Cocito Joe Michael Disc valve for vacuum board
US3402911A (en) * 1966-10-06 1968-09-24 Conco Engineering Works Inc Loading balancer
US3434493A (en) * 1967-09-18 1969-03-25 Ltv Electrosystems Inc Flow-sensitive shutoff valve
US3561471A (en) * 1968-10-29 1971-02-09 Asa D Sands Safety valve
US3635442A (en) * 1969-10-08 1972-01-18 Ingersoll Rand Co Air balancer safety system
US3675899A (en) * 1970-05-27 1972-07-11 Lorne J Mckendrick Hoist and balancing apparatus

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2901219A (en) * 1957-04-04 1959-08-25 Gardner Denver Co Load balancer for hoists
US2939431A (en) * 1957-04-04 1960-06-07 Gardner Denver Co Load balancing device
GB1012460A (en) * 1963-02-07 1965-12-08 Jerry Kirsch Constant speed reciprocable hydro-pneumatic retarding device
US3307819A (en) * 1965-04-12 1967-03-07 Cocito Joe Michael Disc valve for vacuum board
US3259352A (en) * 1965-06-22 1966-07-05 Conco Engineering Works Inc Loading balancer assembly
US3402911A (en) * 1966-10-06 1968-09-24 Conco Engineering Works Inc Loading balancer
US3434493A (en) * 1967-09-18 1969-03-25 Ltv Electrosystems Inc Flow-sensitive shutoff valve
US3561471A (en) * 1968-10-29 1971-02-09 Asa D Sands Safety valve
US3635442A (en) * 1969-10-08 1972-01-18 Ingersoll Rand Co Air balancer safety system
US3675899A (en) * 1970-05-27 1972-07-11 Lorne J Mckendrick Hoist and balancing apparatus

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3880393A (en) * 1973-06-04 1975-04-29 Conco Inc Load balancer with balance override control
US3917200A (en) * 1973-12-14 1975-11-04 Jay Johnson Pneumatic boom support for hand tools
US3883105A (en) * 1974-06-05 1975-05-13 Reizou Matsumoto Load handling equipment
US4421450A (en) * 1977-05-13 1983-12-20 Kono Toshio Cargo handling apparatus
US4659278A (en) * 1984-02-27 1987-04-21 Stahl Aufzuge & Co. KG Manipulator based on the pantograph principle
US4666364A (en) * 1984-06-19 1987-05-19 Stahl Aufzge Gmbh & Co. Kg Low friction cylinder for manipulators, based on the pantograph principle and equipped with a pneumatic balancer control
US6615710B1 (en) * 1999-11-30 2003-09-09 Ishigaki Company Limited Screw press apparatus
USD712945S1 (en) * 2013-08-01 2014-09-09 Vallon Gmbh Telescope-handling arm
US20240083720A1 (en) * 2021-03-19 2024-03-14 Staccato Technologies Ab Pneumatic load balancing system and method

Also Published As

Publication number Publication date
DE2241173B2 (de) 1977-06-30
SE395874B (sv) 1977-08-29
JPS4837577A (en:Method) 1973-06-02
GB1359943A (en) 1974-07-17
FR2158190A1 (en:Method) 1973-06-15
AU4454672A (en) 1974-01-17
CA967455A (en) 1975-05-13
DE2241173A1 (de) 1973-03-29
IT961405B (it) 1973-12-10
AU465628B2 (en) 1975-10-02
JPS5312663B2 (en:Method) 1978-05-02
FR2158190B1 (en:Method) 1976-01-23
ES406852A1 (es) 1975-10-01

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AS Assignment

Owner name: CONCO-TELLUS INC., MENDOTA, IL. A CORP. OF DE.

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:HEICO, INC.,;REEL/FRAME:003828/0909

Effective date: 19810101

AS Assignment

Owner name: INTERLAKE COMPANIES, INC., THE, A CORP. OF DE, DEL

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:CONCO-TELLUS INC.;REEL/FRAME:005199/0803

Effective date: 19891113