WO2010065972A1 - A method of inhibiting a boom moment from exceeding a predetermined amount about an axis - Google Patents

A method of inhibiting a boom moment from exceeding a predetermined amount about an axis Download PDF

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Publication number
WO2010065972A1
WO2010065972A1 PCT/ZA2009/000105 ZA2009000105W WO2010065972A1 WO 2010065972 A1 WO2010065972 A1 WO 2010065972A1 ZA 2009000105 W ZA2009000105 W ZA 2009000105W WO 2010065972 A1 WO2010065972 A1 WO 2010065972A1
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WO
WIPO (PCT)
Prior art keywords
boom
piston
cylinder assembly
arrangement
axis
Prior art date
Application number
PCT/ZA2009/000105
Other languages
French (fr)
Inventor
Johannes Jacobus Fourie
Original Assignee
Johannes Jacobus Fourie
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 Johannes Jacobus Fourie filed Critical Johannes Jacobus Fourie
Publication of WO2010065972A1 publication Critical patent/WO2010065972A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F17/00—Safety devices, e.g. for limiting or indicating lifting force
    • B66F17/006—Safety devices, e.g. for limiting or indicating lifting force for working platforms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F11/00—Lifting devices specially adapted for particular uses not otherwise provided for
    • B66F11/04—Lifting devices specially adapted for particular uses not otherwise provided for for movable platforms or cabins, e.g. on vehicles, permitting workmen to place themselves in any desired position for carrying out required operations
    • B66F11/044—Working platforms suspended from booms
    • B66F11/046—Working platforms suspended from booms of the telescoping type

Definitions

  • THIS INVENTION relates to a method of inhibiting a boom moment from exceeding a predetermined amount about an axis.
  • the invention relates to a method of inhibiting a boom moment from exceeding a predetermined amount about an axis and to a boom arrangement.
  • Booms are used for a variety of purposes.
  • a boom is mounted on a support for angular displacement relative to the support about an axis.
  • a boom mounted for angular displacement relative to a support on a vehicle, or a carriage, or the like, for example is often used to raise and lower a work platform, or basket, or the like, for example, mounted at a remote end of the boom, or as part of a crane, or the like, for example.
  • Such a boom carrying basket is often used to position one or more individuals at an elevated position to perform a task, such as, to position a fireman at an elevated position to douse a fire, to position an electrician at an elevated position to perform maintenance tasks on cables, or the like, for example.
  • Such booms are often longitudinally adjustable between an extended condition and a retracted condition. Typically, such booms are displaced into retracted conditions when not in use and are extended, in use, to reach greater heights, distances, or elevations, if desired.
  • Typical boom systems are relatively complex, often requiring an angular elevation of the boom to be determined and used as input to a computerised system for stability control purposes.
  • Such computerised systems are generally inappropriate for use on vehicles used in harsh environments, such as, rail infrastructure maintenance vehicles, for example.
  • the inventor believes that a need exists for providing a simplified, noncomputerised boom arrangement arranged to at least inhibit a moment of a boom about an axis from exceeding a predetermined amount.
  • a method of inhibiting a boom moment from exceeding a predetermined amount about an axis including: providing a boom mounted on a support for angular displacement about an axis; selectively pressurizing and depressurizing a piston and cylinder assembly operatively associated with the boom to cause the boom to displace angularly about the axis, the piston and cylinder assembly being operatively connected relative to the boom to act on the boom at a generally constant lever arm distance from the axis; and interrupting pressurizing of the piston and cylinder assembly should an internal pressure of the piston and cylinder assembly reach a predetermined pressure, thereby to inhibit a boom moment about the axis from exceeding a predetermined amount.
  • Selectively pressurizing and depressurizing a piston and cylinder assembly operatively associated with the boom to cause the boom to displace angularly about the axis may include feeding a pressurized fluid to the piston and cylinder assembly through a passage.
  • Interrupting pressurizing of the piston and cylinder assembly should an internal pressure of the piston and cylinder assembly reach a predetermined pressure may include interrupting the feeding of the pressurized fluid to the piston and cylinder assembly in response to the internal pressure of the piston and cylinder assembly reaching a predetermined pressure.
  • Interrupting the feeding of the pressurized fluid to the piston and cylinder assembly in response to the internal pressure of the piston and cylinder assembly reaching a predetermined pressure may include actuating a solenoid valve operatively connected in the passage to block the passage.
  • Actuating a solenoid valve operatively connected in the passage to block the passage may include permitting the solenoid valve to be actuated by the internal pressure of the piston and cylinder assembly when the internal pressure of the piston and cylinder assembly reaches the predetermined pressure.
  • a boom arrangement including: a boom; a support on which the boom is mounted for angular displacement about an axis; a piston and cylinder assembly operatively associated with the boom to cause the boom to displace angularly about the axis in response to selectively pressurizing and depressurizing the piston and cylinder assembly; and an actuation arrangement operatively connecting the piston and cylinder assembly with the boom, the actuation arrangement being arranged to cause the piston and cylinder assembly to act on the boom at a generally constant lever arm distance from the axis.
  • the axis may be parallel to the ground.
  • the actuation arrangement may define an elongate element and a guide arrangement extending part circumferentially about the axis at a generally constant radius, on which guide arrangement the elongate element is carried, such that, when the elongate element is pulled the elongate element acts on the boom at a generally constant lever arm distance from the axis defined by the guide arrangement.
  • the guide arrangement may be fast with the boom.
  • An end portion of the elongate element may be secured relative to the boom.
  • An opposed end portion of the elongate element may be secured relative to a piston rod of the piston and cylinder assembly.
  • the elongate element may be in the form of a chain.
  • the boom arrangement may further include pressurizing means for selectively pressurizing the piston and cylinder assembly by feeding a fluid to the piston and cylinder assembly, to cause the piston and cylinder assembly to pull the elongate element.
  • the boom arrangement may further include interruption means for interrupting pressurizing of the piston and cylinder assembly by interrupting the feeding of the fluid to the piston and cylinder assembly should an internal pressure of the piston and cylinder assembly reach a predetermined pressure, thereby to inhibit a moment of the boom about the axis from exceeding a predetermined amount.
  • the interruption means may include a solenoid valve for interrupting the feeding of the fluid to the piston and cylinder assembly in response to the internal pressure of the piston and cylinder assembly reaching the predetermined pressure.
  • the solenoid valve may be operatively connected to the piston and cylinder assembly to be actuated by an internal pressure of the piston and cylinder assembly when the internal pressure of the piston and cylinder assembly reaches the predetermined pressure.
  • Figure 1 shows a schematic three dimensional view of a height adjustable work platform embodying a boom arrangement in accordance with an embodiment of the invention
  • Figure 2 shows a schematic side view of the height adjustable work platform shown in Figure 1 of the drawings, a boom of the boom arrangement being in a retracted condition;
  • Figure 3 shows a schematic side view of the height adjustable work platform shown in Figures 1 and 2 of the drawings, the boom of the boom arrangement being in an extended condition;
  • Figure 4 shows a schematic diagram indicating interruption means of the boom arrangement, the interruption means being arranged, in use, to interrupt pressurizing of a piston and cylinder assembly of the boom arrangement by interrupting feeding of fluid to, or removal of fluid from, the piston and cylinder assembly should an internal pressure of the piston and cylinder assembly reach a predetermined pressure;
  • Figure 5 shows a schematic diagram of the boom arrangement and shows how pressurizing of the piston and cylinder assembly is interrupted should an internal pressure of the piston and cylinder assembly reach a predetermined pressure, thereby, in use, to inhibit a boom moment about an axis from exceeding a predetermined amount.
  • a boom arrangement in accordance with an embodiment of the invention, is generally indicated by reference numeral 10.
  • the boom arrangement 10 is shown embodied in a height adjustable work platform, generally indicated by reference numeral 12.
  • boom arrangement 10 is shown in an embodiment in which the boom arrangement 10 is embodied in a height adjustable work platform 12, it will be appreciated that the field of application of the boom arrangement 10 is not limited to such an application only, but extends to boom arrangements in general, irrespective of the particular application. Accordingly, the boom arrangement 10 can be embodied in a crane, or the like, for example.
  • the boom arrangement 10 includes a boom 14.
  • the boom arrangement 10 further includes a support 16 on which the boom 14 is mounted for angular displacement about an axis 18, as indicated by arrows AA in Figures 2 and 3 of the drawings.
  • the axis 18 is parallel to the ground (not shown).
  • the boom 14 is selectively extendable and retractable, as indicated by arrows EE.
  • a piston and cylinder assembly is provided, as generally indicated by reference numeral 20.
  • a pair of piston and cylinder assemblies 20 is provided.
  • a single piston and cylinder assembly 20 can be used instead.
  • a second piston and cylinder assembly 20 is provided for safety reasons in the event of failure of one of the piston and cylinder assemblies 20.
  • the piston and cylinder assembly 20 is operatively associated with the boom 14 to cause the boom 14 to displace angularly about the axis 18 as indicated by arrows AA in response to selectively pressurizing and depressurizing the piston and cylinder assembly 20. It will be appreciated that, selectively pressurizing and depressurizing the piston and cylinder assembly 20, causes a piston rod 22 of the piston and cylinder assembly 20 selectively to extend and retract, as indicated by arrows BB.
  • An actuation arrangement generally indicated by reference numeral 24, operatively connecting the piston and cylinder assembly 20 with the boom 14, is provided.
  • the actuation arrangement 24 is arranged to cause the piston and cylinder assembly 20 to act on the boom 14 at a generally constant lever arm distance, as indicated by arrow C, from the axis 18.
  • the actuation arrangement 24 defines an elongate element 26 and a guide arrangement 28 extending part circumferentially about the axis 18.
  • the guide arrangement 28 defines a part circumferentially extending surface on which the elongate element is carried, the surface extending part circumferentially about the axis 18 at a generally constant radius.
  • the elongate element 26 can be in the form of a chain, such as a leaf chain, or the like, for example.
  • the elongate element 26 is carried on the guide arrangement 28, such that, when the elongate element 26 is pulled, the elongate element 26 acts on the boom 14 at the generally constant lever arm distance C from the axis 18 defined by the guide arrangement 28, thereby to cause the boom 14 to be raised.
  • the guide arrangement 28 forms part of or is fast with the boom 14.
  • An end portion 26.1 of the elongate element 26 is secured relative to the boom 14.
  • An opposed end portion 26.2 of the elongate element 26 is secured relative to the piston rod 22 of the piston and cylinder assembly 20.
  • the boom arrangement 10 further includes pressurizing means, generally indicated at 30.
  • the pressurizing means 30 can be in the form of an hydraulic pump, or the like, for example, for selectively pressurizing the piston and cylinder assembly 20 by feeding a fluid to the piston and cylinder assembly 20 through a passage 32.
  • an associated return line and storage tank is provided as well.
  • the piston and cylinder assembly 20 is caused selectively to extend, or retract, in response to feeding fluid to, or removing fluid from, the piston and cylinder assembly 20.
  • the piston and cylinder assembly 20 is arranged to pull the elongate element 26 in response to being pressurized to cause the piston and cylinder assembly 20 to retract.
  • the boom arrangement 10 further includes interruption means, generally indicated at 34, for interrupting pressurizing of the piston and cylinder assembly 20 by interrupting the feeding of fluid to, or removal of fluid from, the piston and cylinder assembly 20, should an internal pressure of the piston and cylinder assembly 20 reach a predetermined pressure, thereby to interrupt further extension, or retraction, of the piston and cylinder assembly 20.
  • interruption means generally indicated at 34, for interrupting pressurizing of the piston and cylinder assembly 20 by interrupting the feeding of fluid to, or removal of fluid from, the piston and cylinder assembly 20, should an internal pressure of the piston and cylinder assembly 20 reach a predetermined pressure, thereby to interrupt further extension, or retraction, of the piston and cylinder assembly 20.
  • the interruption means 34 includes a solenoid valve 36 for interrupting the feeding of the fluid to, or removal of fluid from, the piston and cylinder assembly 20.
  • the solenoid valve 36 is arranged to interrupt fluid flow to, or from, the piston and cylinder assembly 20 in response to the internal pressure of the piston and cylinder assembly 20 reaching the predetermined pressure.
  • the solenoid valve 36 is operatively connected to the piston and cylinder assembly 20 to be actuated by an internal pressure of the piston and cylinder assembly 20 when the internal pressure of the piston and cylinder assembly reaches the predetermined pressure. To this end, the solenoid valve 36 is operatively connected to the piston and cylinder assembly 20 through a pilot line 38 to be exposed to the internal pressure of the piston and cylinder assembly 20.
  • an operator of the boom arrangement 10 can selectively cause the boom to displace angularly about the axis 18. This is typically achieved by regulating the pressure in the piston and cylinder assembly 20.
  • the operator can selectively cause the boom 14 to extend and retract. Extension and retraction of the boom 14 can be controlled in any appropriate manner, such as, by an electrical system with associated transmission elements, or a hydraulic system with associated conduits, or the like, for example. As an angular position of the boom 14 about the axis 18 and the length of the boom 14 are varied, a moment of the boom about the axis 18 varies.
  • the moment of the boom 14 is inhibited from exceeding a predetermined amount. Since the piston and cylinder assembly 20 acts on the boom 14 at a generally constant lever arm distance C, this can be achieved by restricting the pressure in the piston and cylinder assembly 20 from exceeding a corresponding appropriate amount. Accordingly, as soon as the pressure in the piston and cylinder assembly 20 reaches the predetermined amount, fluid flow, or feed, to, or from, the piston and cylinder assembly 20 is automatically interrupted through the interruption means 34.

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  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Forklifts And Lifting Vehicles (AREA)

Abstract

The boom arrangement (10) includes a boom (14) and a support (16) on which the boom (14) is mounted for angular displacement about an axis (18), as indicated by arrows AA. A piston and cylinder assembly (20) is provided, which assembly (20) is operatively associated with the boom (14) to cause the boom (14) to displace angularly about the axis (18) as indicated by arrows AA in response to selectively pressurizing and depressurizing the assembly (20). An actuation arrangement (24) is arranged to cause the assembly (20) to act on the boom (14) at a generally constant lever arm distance, as indicated by arrow C, from the axis (18).

Description

A METHOD OF INHIBITING A BOOM MOMENT FROM EXCEEDING A PREDETERMINED AMOUNT ABOUT AN AXIS
Field of the Invention
THIS INVENTION relates to a method of inhibiting a boom moment from exceeding a predetermined amount about an axis. In particular, the invention relates to a method of inhibiting a boom moment from exceeding a predetermined amount about an axis and to a boom arrangement.
Background to the Invention
Booms are used for a variety of purposes. In many cases, a boom is mounted on a support for angular displacement relative to the support about an axis. For example, a boom mounted for angular displacement relative to a support on a vehicle, or a carriage, or the like, for example, is often used to raise and lower a work platform, or basket, or the like, for example, mounted at a remote end of the boom, or as part of a crane, or the like, for example. Such a boom carrying basket is often used to position one or more individuals at an elevated position to perform a task, such as, to position a fireman at an elevated position to douse a fire, to position an electrician at an elevated position to perform maintenance tasks on cables, or the like, for example.
Such booms are often longitudinally adjustable between an extended condition and a retracted condition. Typically, such booms are displaced into retracted conditions when not in use and are extended, in use, to reach greater heights, distances, or elevations, if desired.
When such booms are mounted on a vehicle, or a carriage, or the like, for example, and such booms are extended generally vertically, a moment is normally exercised about an axis about which the boom is angularly displaceably mounted on the vehicle. Should the boom then be lowered toward the horizontal, such a moment increases. Depending on the length and mass of the boom and any load which may be carried by the boom, the moment can increase to an amount causing the vehicle to topple over.
Typical boom systems are relatively complex, often requiring an angular elevation of the boom to be determined and used as input to a computerised system for stability control purposes. Such computerised systems are generally inappropriate for use on vehicles used in harsh environments, such as, rail infrastructure maintenance vehicles, for example.
The inventor believes that a need exists for providing a simplified, noncomputerised boom arrangement arranged to at least inhibit a moment of a boom about an axis from exceeding a predetermined amount.
Summary of the invention
According to a first aspect of the invention, there is provided a method of inhibiting a boom moment from exceeding a predetermined amount about an axis, the method including: providing a boom mounted on a support for angular displacement about an axis; selectively pressurizing and depressurizing a piston and cylinder assembly operatively associated with the boom to cause the boom to displace angularly about the axis, the piston and cylinder assembly being operatively connected relative to the boom to act on the boom at a generally constant lever arm distance from the axis; and interrupting pressurizing of the piston and cylinder assembly should an internal pressure of the piston and cylinder assembly reach a predetermined pressure, thereby to inhibit a boom moment about the axis from exceeding a predetermined amount. Selectively pressurizing and depressurizing a piston and cylinder assembly operatively associated with the boom to cause the boom to displace angularly about the axis may include feeding a pressurized fluid to the piston and cylinder assembly through a passage.
Interrupting pressurizing of the piston and cylinder assembly should an internal pressure of the piston and cylinder assembly reach a predetermined pressure may include interrupting the feeding of the pressurized fluid to the piston and cylinder assembly in response to the internal pressure of the piston and cylinder assembly reaching a predetermined pressure. .
Interrupting the feeding of the pressurized fluid to the piston and cylinder assembly in response to the internal pressure of the piston and cylinder assembly reaching a predetermined pressure may include actuating a solenoid valve operatively connected in the passage to block the passage.
Actuating a solenoid valve operatively connected in the passage to block the passage may include permitting the solenoid valve to be actuated by the internal pressure of the piston and cylinder assembly when the internal pressure of the piston and cylinder assembly reaches the predetermined pressure.
According to another aspect of the invention, there is provided a boom arrangement including: a boom; a support on which the boom is mounted for angular displacement about an axis; a piston and cylinder assembly operatively associated with the boom to cause the boom to displace angularly about the axis in response to selectively pressurizing and depressurizing the piston and cylinder assembly; and an actuation arrangement operatively connecting the piston and cylinder assembly with the boom, the actuation arrangement being arranged to cause the piston and cylinder assembly to act on the boom at a generally constant lever arm distance from the axis.
The axis may be parallel to the ground.
The actuation arrangement may define an elongate element and a guide arrangement extending part circumferentially about the axis at a generally constant radius, on which guide arrangement the elongate element is carried, such that, when the elongate element is pulled the elongate element acts on the boom at a generally constant lever arm distance from the axis defined by the guide arrangement.
The guide arrangement may be fast with the boom.
An end portion of the elongate element may be secured relative to the boom. An opposed end portion of the elongate element may be secured relative to a piston rod of the piston and cylinder assembly.
The elongate element may be in the form of a chain.
The boom arrangement may further include pressurizing means for selectively pressurizing the piston and cylinder assembly by feeding a fluid to the piston and cylinder assembly, to cause the piston and cylinder assembly to pull the elongate element.
The boom arrangement may further include interruption means for interrupting pressurizing of the piston and cylinder assembly by interrupting the feeding of the fluid to the piston and cylinder assembly should an internal pressure of the piston and cylinder assembly reach a predetermined pressure, thereby to inhibit a moment of the boom about the axis from exceeding a predetermined amount. The interruption means may include a solenoid valve for interrupting the feeding of the fluid to the piston and cylinder assembly in response to the internal pressure of the piston and cylinder assembly reaching the predetermined pressure.
The solenoid valve may be operatively connected to the piston and cylinder assembly to be actuated by an internal pressure of the piston and cylinder assembly when the internal pressure of the piston and cylinder assembly reaches the predetermined pressure.
Detailed Description of the invention
An embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:
Figure 1 shows a schematic three dimensional view of a height adjustable work platform embodying a boom arrangement in accordance with an embodiment of the invention;
Figure 2 shows a schematic side view of the height adjustable work platform shown in Figure 1 of the drawings, a boom of the boom arrangement being in a retracted condition;
Figure 3 shows a schematic side view of the height adjustable work platform shown in Figures 1 and 2 of the drawings, the boom of the boom arrangement being in an extended condition;
Figure 4 shows a schematic diagram indicating interruption means of the boom arrangement, the interruption means being arranged, in use, to interrupt pressurizing of a piston and cylinder assembly of the boom arrangement by interrupting feeding of fluid to, or removal of fluid from, the piston and cylinder assembly should an internal pressure of the piston and cylinder assembly reach a predetermined pressure; and
Figure 5 shows a schematic diagram of the boom arrangement and shows how pressurizing of the piston and cylinder assembly is interrupted should an internal pressure of the piston and cylinder assembly reach a predetermined pressure, thereby, in use, to inhibit a boom moment about an axis from exceeding a predetermined amount.
Referring to Figures 1 to 3 of the drawings, a boom arrangement, in accordance with an embodiment of the invention, is generally indicated by reference numeral 10. The boom arrangement 10 is shown embodied in a height adjustable work platform, generally indicated by reference numeral 12.
Although the boom arrangement 10 is shown in an embodiment in which the boom arrangement 10 is embodied in a height adjustable work platform 12, it will be appreciated that the field of application of the boom arrangement 10 is not limited to such an application only, but extends to boom arrangements in general, irrespective of the particular application. Accordingly, the boom arrangement 10 can be embodied in a crane, or the like, for example.
The boom arrangement 10 includes a boom 14. The boom arrangement 10 further includes a support 16 on which the boom 14 is mounted for angular displacement about an axis 18, as indicated by arrows AA in Figures 2 and 3 of the drawings. The axis 18 is parallel to the ground (not shown). Typically, the boom 14 is selectively extendable and retractable, as indicated by arrows EE.
A piston and cylinder assembly is provided, as generally indicated by reference numeral 20. In this case, a pair of piston and cylinder assemblies 20 is provided. However, it will be appreciated that a single piston and cylinder assembly 20 can be used instead. Typically, a second piston and cylinder assembly 20 is provided for safety reasons in the event of failure of one of the piston and cylinder assemblies 20.
The piston and cylinder assembly 20 is operatively associated with the boom 14 to cause the boom 14 to displace angularly about the axis 18 as indicated by arrows AA in response to selectively pressurizing and depressurizing the piston and cylinder assembly 20. It will be appreciated that, selectively pressurizing and depressurizing the piston and cylinder assembly 20, causes a piston rod 22 of the piston and cylinder assembly 20 selectively to extend and retract, as indicated by arrows BB.
An actuation arrangement, generally indicated by reference numeral 24, operatively connecting the piston and cylinder assembly 20 with the boom 14, is provided. The actuation arrangement 24 is arranged to cause the piston and cylinder assembly 20 to act on the boom 14 at a generally constant lever arm distance, as indicated by arrow C, from the axis 18.
The actuation arrangement 24 defines an elongate element 26 and a guide arrangement 28 extending part circumferentially about the axis 18. Typically, the guide arrangement 28 defines a part circumferentially extending surface on which the elongate element is carried, the surface extending part circumferentially about the axis 18 at a generally constant radius.
Typically, the elongate element 26 can be in the form of a chain, such as a leaf chain, or the like, for example. The elongate element 26 is carried on the guide arrangement 28, such that, when the elongate element 26 is pulled, the elongate element 26 acts on the boom 14 at the generally constant lever arm distance C from the axis 18 defined by the guide arrangement 28, thereby to cause the boom 14 to be raised.
Typically, the guide arrangement 28 forms part of or is fast with the boom 14. An end portion 26.1 of the elongate element 26 is secured relative to the boom 14. An opposed end portion 26.2 of the elongate element 26 is secured relative to the piston rod 22 of the piston and cylinder assembly 20.
As can best be seen with reference to Figure 4 of the drawings, in which like reference numerals have been used to designate similar parts, or features, unless other wise stated, the boom arrangement 10 further includes pressurizing means, generally indicated at 30. The pressurizing means 30 can be in the form of an hydraulic pump, or the like, for example, for selectively pressurizing the piston and cylinder assembly 20 by feeding a fluid to the piston and cylinder assembly 20 through a passage 32. Typically, an associated return line and storage tank is provided as well. Accordingly, the piston and cylinder assembly 20 is caused selectively to extend, or retract, in response to feeding fluid to, or removing fluid from, the piston and cylinder assembly 20. It will be appreciated that in the embodiment shown in the drawings, the piston and cylinder assembly 20 is arranged to pull the elongate element 26 in response to being pressurized to cause the piston and cylinder assembly 20 to retract.
The boom arrangement 10 further includes interruption means, generally indicated at 34, for interrupting pressurizing of the piston and cylinder assembly 20 by interrupting the feeding of fluid to, or removal of fluid from, the piston and cylinder assembly 20, should an internal pressure of the piston and cylinder assembly 20 reach a predetermined pressure, thereby to interrupt further extension, or retraction, of the piston and cylinder assembly 20. In this way, a moment, as indicated by arrow D in Figure 5 of the drawings, by the boom 14 about the axis 18, is inhibited from exceeding a predetermined amount.
The interruption means 34 includes a solenoid valve 36 for interrupting the feeding of the fluid to, or removal of fluid from, the piston and cylinder assembly 20. The solenoid valve 36 is arranged to interrupt fluid flow to, or from, the piston and cylinder assembly 20 in response to the internal pressure of the piston and cylinder assembly 20 reaching the predetermined pressure.
The solenoid valve 36 is operatively connected to the piston and cylinder assembly 20 to be actuated by an internal pressure of the piston and cylinder assembly 20 when the internal pressure of the piston and cylinder assembly reaches the predetermined pressure. To this end, the solenoid valve 36 is operatively connected to the piston and cylinder assembly 20 through a pilot line 38 to be exposed to the internal pressure of the piston and cylinder assembly 20.
In use, an operator of the boom arrangement 10 can selectively cause the boom to displace angularly about the axis 18. This is typically achieved by regulating the pressure in the piston and cylinder assembly 20. In addition, the operator can selectively cause the boom 14 to extend and retract. Extension and retraction of the boom 14 can be controlled in any appropriate manner, such as, by an electrical system with associated transmission elements, or a hydraulic system with associated conduits, or the like, for example. As an angular position of the boom 14 about the axis 18 and the length of the boom 14 are varied, a moment of the boom about the axis 18 varies.
To inhibit the moment of the boom 14 from exceeding a predetermined amount, so as to inhibit the boom 14 from causing a vehicle, or a carriage, or the like, on which it is mounted, from toppling over, the moment is inhibited from exceeding a predetermined amount. Since the piston and cylinder assembly 20 acts on the boom 14 at a generally constant lever arm distance C, this can be achieved by restricting the pressure in the piston and cylinder assembly 20 from exceeding a corresponding appropriate amount. Accordingly, as soon as the pressure in the piston and cylinder assembly 20 reaches the predetermined amount, fluid flow, or feed, to, or from, the piston and cylinder assembly 20 is automatically interrupted through the interruption means 34. It will be appreciated tήat when the interruption means 34 causes fluid flow to be interrupted, further extension of the boom 14 is also inhibited. This can be achieved by automatically causing electrical current flow to an electrical drive system, or fluid flow to a hydraulic system, arranged to cause the boom 14 to extend, to be interrupted, while still permitting electrical current flow to the electrical drive system, or fluid flow to the hydraulic system, to cause the boom 14 to retract.
In this way, a vehicle, or a carriage, or the like, on which the boom arrangement 10 is mounted can be inhibited automatically from toppling over.
It is to be appreciated, that the invention is not limited to any specific embodiment or configuration as hereinbefore generally described or illustrated.

Claims

Claims
1. A method of inhibiting a boom moment from exceeding a predetermined amount about an axis, the method including:-
- providing a boom mounted on a support, so that the boom is angularly displaceable about an axis;
- selectively pressurizing and depressurizing a piston and cylinder assembly operatively associated with the boom to cause the boom to displace angularly about the axis, the piston and cylinder assembly being operatively connected relative to the boom to act on the boom at a generally constant lever arm distance from the axis; and
- interrupting pressurizing of the piston and cylinder assembly should an internal pressure of the piston and cylinder assembly reach a predetermined pressure, thereby to inhibit a boom moment about the axis from exceeding a predetermined amount.
2. A method as claimed in claim 1 , wherein a pressurised fluid is fed to the piston and cylinder assembly through a passage to selectively pressurize and depressurize the assembly.
3. A method as claimed in claim 1 or claim 2, wherein feeding of the pressurized fluid to the piston and cylinder assembly is interrupted in response to the internal pressure of the piston and cylinder assembly reaching a predetermined pressure.
4. A method as claimed in claim 3, wherein interrupting the feeding of the pressurized fluid to the piston and cylinder assembly includes actuating a solenoid valve operatively connected in the passage to block the passage.
5. A method as claimed in claim 4, wherein actuation of the solenoid valve includes permitting the solenoid valve to be actuated by the internal pressure of the piston and cylinder assembly when the internal pressure of the piston and cylinder assembly reaches the predetermined pressure.
6. A boom arrangement including:-
- a boom;
- a support on which the boom is displaceably mounted so as to permit angular displacement of the boom about an axis;
- a piston and cylinder assembly operatively associated with the boom to cause the boom to displace angularly about the axis in response to selectively pressurizing and depressurizing the piston and cylinder assembly; and
- an actuation arrangement operatively connecting the piston and cylinder assembly with the boom, the actuation arrangement being arranged to cause the piston and cylinder assembly to act on the boom at a generally constant lever arm distance from the axis.
7. A boom arrangement as claimed in claim 6, wherein the actuation arrangement defines an elongate element and a guide arrangement extending part circumferentially about the axis at a generally constant radius, on which guide arrangement the elongate element is carried, such that, when the elongate element is pulled the elongate element acts on the boom at a generally constant lever arm distance from the axis defined by the guide arrangement.
8. A boom arrangement as claimed in claim 7, wherein the guide arrangement forms part of the boom.
9. A boom arrangement as claimed in claim 7 or claim 8, wherein an end portion of the elongate element is secured relative to the boom.
10. A boom arrangement as claimed in claim 9, wherein an opposed end portion of the elongate element is secured relative to a piston rod of the piston and cylinder assembly.
11. A boom arrangement as claimed in claim 10, wherein the elongate element is a chain.
12. A boom arrangement as claimed in any one of claims 6 to 11 , wherein the boom arrangement includes pressurizing means for selectively pressurizing the piston and cylinder assembly by feeding a fluid to the piston and cylinder assembly, to cause the piston and cylinder assembly to pull the elongate element.
13. A boom arrangement as claimed in claim 12, wherein the boom arrangement includes interruption means for interrupting pressurizing of the piston and cylinder assembly by interrupting the feeding of the fluid to the piston and cylinder assembly should an internal pressure of the piston and cylinder assembly reach a predetermined pressure, thereby to inhibit a moment of the boom about the axis from exceeding a predetermined amount.
14. A boom arrangement as claimed in claim 13, wherein the interruption means includes a solenoid valve for interrupting the feeding of the fluid to the piston and cylinder assembly in response to the internal pressure of the piston and cylinder assembly reaching the predetermined pressure.
15. A boom arrangement as claimed in claim 14, wherein the solenoid valve is operatively connected to the piston and cylinder assembly to be actuated by an internal pressure of the piston and cylinder assembly when the internal pressure of the piston and cylinder assembly reaches the predetermined pressure.
16. A boom arrangement substantially as hereinbefore described or exemplified.
17. A boom arrangement as specifically described with reference to or as illustrated in any one of the accompanying drawings.
18. A boom arrangement including any new and inventive integer or combination of integers, substantially as herein described.
19. A method of inhibiting a boom moment from exceeding a predetermined amount about an axis substantially as hereinbefore described or exemplified.
20. A method of inhibiting a boom moment from exceeding a predetermined amount about an axis including any new and inventive integer or combination of integers, substantially as herein described.
PCT/ZA2009/000105 2008-12-01 2009-11-30 A method of inhibiting a boom moment from exceeding a predetermined amount about an axis WO2010065972A1 (en)

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ZA2008/10197 2008-12-01
ZA200810197 2008-12-01

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115748448A (en) * 2022-12-07 2023-03-07 罗冬成 Highway bridge detection maintenance vehicle and working method thereof

Citations (1)

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Publication number Priority date Publication date Assignee Title
US4861224A (en) * 1988-06-14 1989-08-29 Hi-Ranger, Inc. Aerial lift including overload sensing system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4861224A (en) * 1988-06-14 1989-08-29 Hi-Ranger, Inc. Aerial lift including overload sensing system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115748448A (en) * 2022-12-07 2023-03-07 罗冬成 Highway bridge detection maintenance vehicle and working method thereof
CN115748448B (en) * 2022-12-07 2023-09-08 罗冬成 Road bridge detection maintenance vehicle and working method thereof

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