Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B66—HOISTING; LIFTING; HAULING
  • B66D—CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS
  • B66D1/00—Rope, cable, or chain winding mechanisms; Capstans
  • B66D1/28—Other constructional details
  • B66D1/40—Control devices
  • B66D1/42—Control devices non-automatic
  • B66D1/44—Control devices non-automatic pneumatic of hydraulic
• • 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
  • B66C23/88—Safety gear
  • B66C23/90—Devices for indicating or limiting lifting moment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B66—HOISTING; LIFTING; HAULING
  • B66D—CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS
  • B66D5/00—Braking or detent devices characterised by application to lifting or hoisting gear, e.g. for controlling the lowering of loads
  • B66D5/02—Crane, lift hoist, or winch brakes operating on drums, barrels, or ropes
  • B66D5/24—Operating devices
  • B66D5/26—Operating devices pneumatic or hydraulic

Definitions

• the present invention relates to hydraulic systems for emergency shutdown and operation of a crane and more particularly to such hydraulic systems which are capable of controlling the load of a crane during an emergency control situation.
• NMD Maritime Directorate
• the emergency release switch or handle shall be effectively secured against inadvertent use, and the winch shall automatically, with a soft characteristic, return to normal hoisting, braking or holding conditions when the emergency release is disconnected".
• item 5.11 requires that "the brakes shall be designed and constructed in such a way that it, within the shortest possible time, will be possible to lower and stop the full hook capacity manually and under full control in case of power failure or failure in the control system.
• an alternative emergency power system independent of the main power system, may be required".
• This invention provides a hydraulic control system for operation of a winding means having a drive means associated therewith.
• the control system comprises a means for generating hydraulic power, conduit means capable of supplying hydraulic power to the drive means, a plurality of valving means capable of selectively supplying the hydraulic power to the drive means and a plurality of hand operable control means capable of effecting several operating modes of the control system by directing the hydraulic power to a select group of said conduit means and said valving means for a particular mode.
• One of the operating modes besides normal operation, is a mode for letting out a load on the winding means when the normal hydraulic power is lost, while controlling the speed with which the load unwinds the winding means.
• Additional operating modes for the control system include a means for letting out a load on the winding means when there is a an accidental over-load, while maintaining a substantially constant tension from the winding means to the load; and a means for letting out a load on the winding means when there is an accidental over-load and there is total loss of normal hydraulic power.
• Figure 1 is a diagra atic schematic representataion of one embodiment of the hydraulic system designed for the present invention, wherein one mode of operation, i.e. the emergency non-powered load lowering mode for the auxiliary or whip drum, is highlighted.
• one mode of operation i.e. the emergency non-powered load lowering mode for the auxiliary or whip drum
• Figure 2 is a diagramatic schematic representation of one embodiment of the hydraulic system of the present invention in which another mode, i.e. the emergency non-powered load lowering mode for the main drum, is highlighted.
• Figure 3 is a diagramatic schematic representation of one embodiment of the hydraulic system of the present invention wherein another mode, i.e. the emergency release with constant tension with power unit operating, is highlighted.
• Figure 4 is a diagramatic schematic representation of one embodiment of the hydraulic system of the present invention wherein another mode of operation is shown, i.e. the emergency release mode without power unit operating, is highlighted..
• Figure 5 is a perspective view showing the manual system for effecting a shutdown, in the event of an emergency, in which the system is designed to automatically set all of the brakes on the crane when the system is activated by the operator. In the event of a power failure it is designed to automatically set all of the brakes on the crane.
• Figure 6 is diagramatic schematic representation of the emergency shutdown of the electrical element of the emergency shutdown shown in figure 5.
• Figure 7 is a diagramatic schematic representation of one embodiment of the hydraulic circuit for the crane emergency shutdown system, shown in perspective in figure 5.
• the present invention is shown and represented by a single hydraulic system that is only one possible embodiment of such a control system.
• This hydraulic system is capable of operating in several different modess a normal control mode, an emergency non-powered load lowering mode for the main drum, an emergency non-powered load lowering mode for the auxiliary or whip drum, an emergency release mode with and without constant tension for the auxiliary or whip drum (with the addition of some valves and minor modification to the circuit the emergency release could be used for the main drum or in combination on both drums) .
• the entire hydraulic system for the crane includes a number of components not represented in the hydraulic control system for the four modes of operation, shown in Figures 1-4, and for ease and simplification only those components of the overall crane hydraulic system necessary for the emergency control operating modes of the crane hydraulic system are referred to and shown in the following description.
• the crane emergency control hydraulic system that is shown in figures 1 through 4 includes a pair of operator control elements: one for normal crane control and the other for emergency crane control, 2 pair of brakes: one for the main hoist drum, and one for the auxiliary or whip hoist drum; a pair of motors and their associated boxes: one for the main hoist drum and one for the auxiliary or whip hoist drum; a bank of four detented hand control valves for switching the crane hydraulic control system into one or another of its operating modes, a pressure make-up system for providing emergency power in the event of loss of power, such power make-up system being independent of the normal crane operating power system, and of several directional control valves controlling the direction of pressure flow generated either by the normal crane operating power system or the pressure make-up system, through the lines for effecting the different modes of operation.
• the crane control system has been shown in each of its independently operating modes by highlighting those elements of the emergency hydraulic control system that are used in each of the individual operating modes.
• the hydraulic control system will be described in terms of its several modes of operations.
• the typical crane system is a Skagit Series Three Hundred Pedestal Crane powered by a two hundred and seventy horse power (270 h.p.) diesel engine operating at one thousand nine hundred and eighty (1980) rpm.
• the system could also be employed with other types of prime movers such as an electric motor.
• the horsepower rating of the prime mover is dependent on the hoist capacity and speed. The engine supplies
• the engine power is controlled by means of a pair of operator controls that are operable in the normal crane operation condition.
• the emergency control system can be activated in any of a variety of siutations.
• the primary purpose for engaging the emergency controls would be a loss of power, either total electrical power or a total or partial loss of hydraulic power, that results in a loss of power to the hydraulic controls, or accidental overload.
• the first of the emergency control circuits to be described, the emergency non-powered load lowering sytem, is shown in Figures 1 and 2 for the auxiliary or whip drum and the main drum, respectively.
• Both the main hoist drum and the auxiliary or whip hoist drum are provided with this system in order to allow the crane operator to lower a suspended load without power being supplied by the crane's diesel engine for powering the hydraulic circuitry and yet still enable the operator to handle the suspended load under full control.
• the system provides a means for releasing the brakes for either the main hoist or the auxiliary or whip hoist, a means for controlling the speed with which the load suspended from either the main hoist or the auxiliary or whip hoist is lowered, and a means for stopping the load from lowering further, should that be ' necessary.
• the non-powered load lowering system is primarily designed for operation where there is a loss of electrical power or a loss of the engine and the resulting loss of the hydraulic pressure necessary to operate the crane hydraulic control system to lower the load in normal operation .
• use of the emergency non-powered load lowering system does require that the hydraulic motors of _the main hoist or the auxiliary or whi hoist (which ever is being used) be in operational condition, i. e. the shutdown emergency can not have been caused by a failure of the hydraulic motors such that they are no longer functional as motors (or as pumps in a reverse direction). should this be the case, then the non-powered load lowering system would not be able to function as anticipate .
• the crane operator pulls one of the several detented hand valve control elements which are located in his cab console and which are positioned preferably near his right hand or within easy reach.
• the functioning of the non-powered load lowering system for each of the two modes of operation, i.e. main hoist or the auxiliary or whip hoist is identical and many common components are used in each system.
• the operator activates the auxiliary or whip hoist non-powered load lowering mode by pulling the push-pull cable that triggers detented hand valve 20.
• valve 20 When valve 20 is repositioned to the left hand port (herein after all references to valve ports are relative to the particular drawing Figure being described) pressure from accumulator 11 will flow via line 80 into line 82 and then through valve 20 and up to line 95 and 97. The accumulator pressure will then be directed via line 97 to shuttle valve 62 where it is directed via line 100 and energizes control valve 67, and to shuttle valves 38 and 39. From line 95 pressure is directed to shuttle valve 23 and then to the pilot positioning element on directional control valve 28 which allows relief valve 26 to become functional at a reduced pressure by venting relief valve 26 pilot port to the cranes hydraulic reservoir 68. The pressure that is directed to - shuttle valve 38 goes via line 105 to the right hand pilot control element on directional valve 37.
• valve 42 also serves to isolate the normal hydraulic system. Movement of valve 42 to the left serves to isolate any incoming pressure from the auxiliary or whip hoist motor. The auxiliary or whip hoist motor creates the pressure in line 117 when the brake (47) is released and speed control valve 29 is actuated by the crane operator activating the control valve 67.
• the control valve is a modulating joy stick of the dead-man type having two axes of operation.
• the joy stick control handle is located to the front and right of the operator.
• the joy stick control is used by the operator to release the auxiliary or whip hoist brake and to control the now non-powered crane load to lower the load at a controlled speed as determined by the crane operator's use of the joy stick.
• movement of the joy stick or operator control handle to the operator's left applies pressure to the hoist brake.
• a variable pressure is directed to the auxiliary or whip hoist brake sufficient to release the brake. The operator therefor can start and stop load lowering as desired.
• Movement of the operator control handle only in a forward direction will cause an increase in the speed with which the load can be lowered. Combining the two movements, or moving the operator control handle at a forty-five degree angle, the operator can thereby release the brake and also start lowering or stop lowering the load.
• the speed control line from valve 67, line 102 actually delivers its pressure to the left hand pilot positioning element of valve 29. This piloting allows the load induced pressure to enter line 108 and turn motor and pump 25.
• the pump 25b out-put pressure port is connected to the low pressure side of the auxiliary or whip hoist motor which is the suction port when the motor is acting as a pump.
• Pressurized fluid is forced to travel via line 87, via line 86, via line 94 to the auxiliary or whip hoist motor 45 completing the closed loop. Pressurized fluid from line 86 also flows thru check valve 17 to line 80 and into accumulator 11 or the control circuit.
• flow control valve 30 which is set at a fixed flow and is pressure and temperature compensating to thereby limit the flow and the resulting maximum speed of the auxiliary or whip hoist drum when the auxiliary or whip hoist load is lowering.
• flow through the modulating directional control valve 29 is controlled directly by the crane operator via the operator control handle in the cab.
• the pressure signal to the left hand pilot port, piloting the valve to the right, is related to the pilot pressure which in turn is related to the degree to which the operator control handle of valve 67 is moved in the forward direction.
• the crane operator can control the speed with which a load is lowered to an infinite degree of variation by moving the operator control handle within the upper left hand quandrant of the operator control valve 67.
• the crane operator merely moves the non-powered load lowering operator control valve 67 to its normal or centered position. This movement blocks the pressure porting on the operator control and serves to relieve the pressure on the modulating valve 29 (or speed control valve 29), and the pressure on the brake 47 allowing the brake 47 to reset and stop the load from continuing to lower.
• the de-activation of the non-powered load lowering system is accomplished simply by having the crane operator replace the non-powered load lowering auxiliary or whip hoist handle of detented valve 20 to its normal position. This action isolates the non-powered load lowering system and allows the crane's normal operation to be reactivated. Therefore if power is later restored, the operator can proceed to operate the crane in a normal manner.
• the design line speed for load lowering is in the range of from 0 feet per minute when the brake is set to approximately 60 feet per minute as determined by the flow control valve 30.
• the loading required per line is approximately 1,000 pounds to provide this full line speed. Less of a load will reduce the maximum load lowering speed.
• the non-powered load lowering system in the Skagit 300 Series Crane is designed to be capable of handling the crane's full rated capacity.
• the line speeds and pulls given in this paragraph are typical of the Skagit 300 series Cranes. However, the line speeds and pulls for a NPLL system used for another model or make crane may differ considerably from the above.
• the accumulator hand pump is equipped with a hand pump element in order to feed pressure via line 83, through check valve 14 into line 80 and then into the accumulator.
• This hand pump is primarily designed to provide a pressure build-up means should the pressure of the accumulator 11 be bled off prematurely.
• the emergency non-powered load lowering system is also operable in a mode for operating the main hoist drum in a matter very similar to that as described above for the auxiliary or whip hoist drum.
• the crane operator merely pulls the appropriate push-pull cable located in the cab to reposition detented valve 19 which serves a similar function to that of detented valve 20 for the auxiliary or whip hoist drum.
• detented valve 19 When detented valve 19 is repositioned, the pressure flow is conducted from accumulator 11 via line 80 to line 82 and into and through the left hand port of detented valve 19. The pressure is then directed into line 96 and line 98.
• Pressure from line 98 is also directed to shuttle valve 62 and thence to operator control 67, activating the operator control in a manner similar to that for the auxiliary or whip hoist drum mode of the non-powered load lowering system.
• the operator control 67 is used in this instance in the same matter as with the auxiliary or whip hoist drum mode forward movement of the operator control handle causes an increase in the speed with which the load is lowered by directing pressure to the left hand pilot positioning port of the modulating directional (speed) control valve 29. Movement to the left of the operator control handle, directs pressure via line 101 to directional control valve 51 which is in its upper most position, directing pressure into line 120 and into shuttle valve 48 and then into main hoist brake 46. Judicious movement of the operator control handle in the upper left hand quandrant of the control allows for controlled lowering of the load on the main hoist brake in a manner similar to that for the non-powered load lowering system mode for the auxiliary or whip hoist.
• the load is allowed to start lowering thus causing the main hoist motor to rotate backwards and act as a pump. This creates a load-induced flow that travels to line 118. From line 118 the load-induced flow is directed to directional control valve 42 where it is ported to a blocked passage, since directional control valve 42 has been piloted to the right thereby blocking out crane normal circuit. From line 118 the load-induced flow is directed to directional control valve 37 which has been piloted to the right allowing load induced flow to directly transmit through the left hand position and into line 116 directing the load induced flow to directional control valve 35. Valve 35 is in its normal position and the load-induced flow enters line 113 and goes to flow control valve 30.
• flow control valve 30 is set at a fixed flow and is pressure and temperature compensated to limit the maximum speed with which the main hoist drum is allowed to lower. From flow control valve 30, via line 110 the load-induced flow is directed to repositioned modulating directional control valve 29, i.e. the speed control valve, which has been piloted to the right allowing the load induced flow to enter into line 108 which directs it to check valve
• the pump suction port is connected to the crane hydraulic reservoir 68 as with the auxiliary or whip hoist motor non powered load lowering mode.
• the pressure flow is directed via line 87 to lines 85 and 86 and to check valve 24 where the flow is blocked.
• the pressure flow in line 85 is directed to and through check valve 17 and into line
• the flow in line 86 is directed to the main hoist motor 44 completing the closed loop, and line 94.
• the flow entering the main hoist motor 44 serves to prevent the motor 44 from cavitating and the flow in 25b line 94 is blocked at motor 45 and eventually at check valve 52.
• the additional flow created by motor and pump 25 when combined with the load induced flow which has passed through the make-up motor 25(a) provides enough pressure and flow to prevent the main hoist motor 44 from cavitating. Any excess flow is returned to the main crane hydraulic tank 68 through relief valve 26 and/or relief valve 15 when the relief valve settings have been reached.
• the de-activation of the main drum non-powered load lowering mode is accomplished by simply placing the detented valve's 19 push pull handle back to its normal position.
• auxiliary or whip hoist In addition to having the non powered load lowering system associated with the auxiliary or whip hoist there is also an emergency release system for the auxiliary or whip hoist.
• a situation may occur wherein the hook on the auxiliary or whip hoist might become caught or fouled on some moving object, such as a work boat or barge requiring that the auxiliary or whip hoist line be effectively released in order to follow the direction of the moving object and to thereby avoid possible damage to either the moving object on which it is fouled or to the crane itself. If the hook should become so caught or fouled, the crane operator is provided an additional push pull handle for the emergency release system. The crane operator pulls the push-pull handle to activate detented valve
• the pressure that is directed from the precharged accumulator 11 and from the crane's normal control circuit pilot oil supply 103 assuming that the engine is still operating will (a) release the auxiliary or whip hoist brake through a series of shuttle valves; (b) isolate the crane's normal hydraulic speed and direction control circuit through a series of directional control valves; (c) engage the constant tension circuit, assuming that the engine is still operable, through directional y ⁇ OHE control valves; and, (d) activate or engage the make-up circuit if and when it is detected that the engine is not operable, or loss of normal systems hydraulic pressure occur as highlighted in Fig. 4.
• pressure from the crane's normal hydraulic system, generated by the diesel engine in the Skagit series 300 crane is directed via line 103, the pilot oil supply line, to line 104 and to check valve 18.
• Line 104 channels the crane's hydraulic pressure to the pilot port of directional control valve 36 repositioning valve 36 to the right.
• the pressure that enters check valve 18 goes into the accumulator line 80 and then, along with accumulator pressure, is directed via line 80 to line 82 and thence through the repositioned detented control valve 21.
• the pressure flow leaving valve 21 enters line 89 where the pressure is directed to line 90, 91 and 92.
• Line 92 feeds the pressure flow to directional control valve 28 and to line 93.
• the flow from valve 28 is directed to relief valve 26, piloting the relief valve 26 to a preset relief valve.
• Line 93 channels the crane's hydraulic pressure to shuttle valve 50 and then to shuttle valve 49 and to the auxiliary or whip hoist brake 47, releasing the brake. With the release of the hoist brake 47 the auxiliary or whip hoist line is free to follow the load of the moving object and thus is able to pay out or to inhaul as required by the direction of the load of the object.
• the auxiliary or whip hoist drum rotates backwards thus causing the auxiliary or whip hoist 45 to rotate backwards and acts as a pump thus creating its own flow and pressure.
• this load-induced flow pressure generated by the auxiliary or whip hoist motor is proportional to the line tension created by the load of the moving object to which the hoist line is fouled. This load-induced flow acts directly on the hoist pump swash plate control.
• the pressure directed to line 91 is directed into the left hand position of repositioned directional control valve 36 where it is blocked.
• Line 91 also directs the pressure flow to the pilot port of directional control valve 35 porting it to the right, and to the pilot port of directional control valve 55 directing it to the right.
• the pressure flow entering line 90 directs the pressure flow to directional control valves 58, 59 and 61.
• the pressure directed to valve 61 enters the pilot port shifting directional control valve 61 downward and allowing the control pressure on operator control 66 to dump to crane hydraulic tank 68.
• the pressure directed via line 90 to directional control valves 58 and 59 enters the lower pilot ports on the directional control valves 58 and 59 repositioning the valves
• the directional control valve 60 is a torque limiting valve which has been installed adjacent to the hoist pump. This valve 60 is a spool type with two pilot ports at each end, one pressure port, one tank port and two work ports. The work ports are connected to the swash plate control ports 56a and 56b on the hoist pump through normally closed directional control valves 58 and 59 which are opened when the emergency release control is activated by the operator. The high pressure port of the hoist pump is connected to the lower pilot port of torque valve 60. The other two ports are ratio ports.
• a reduced pressure signal is connected to the ratio pilot port on the in-haul or upper end of torque valve 60.
• Pressure reducing valve 63 has been installed to provide this reduced signal from the crane's hydraulic control system.
• the other pilot ratio port, on the outhaul end of torque valve 60, is connected to the tank return circuit or to the crane hydraulic tank 68.
• the torque valve 60 is a valve with a 16:1 ratio - the area of the piston on the ratio port which is connected to the reduced pressure ratio port is 16 times larger than the piston on the lower pilot port.
• This port senses the load induced pressure in line 157 and thus when the load induced pressure exceeds the predetermined reduced pressure by a factor of 16 the valve will shift and cause pressure to be directed to the opposite side of the pump swash plate causing the drum to rotate in the opposite direction allowing the line to payout, when induced pressure becomes less than 16 times the predetermined minimum pressure, the valve will shift back to the in-haul positions. Valves with different ratios are available. The actual pressure of the reduced pressure signal is determined by the minimum line tension that is required by the Norwegian Maritime Directorate or other similar governmental or commercial regulations of standards or customer request, i.e. the reduced signal to the ratio port is set at approximately 100 psi.
• torque valve 60 it would take a pressure in excess of 1600 psi to cause torque valve 60 to shift. ith a fixed predetermined pilot signal at one end of torque valve 60 creating an imbalance, torque valve 60 will shift to the in-haul mode and control pressure will be transmitted through directional control valve 59 to the in-haul port of the hoist pump swash plate control. This causes the pump to go into the in-haul mode. Conversely with the opposite end of torque valve 60 sensing the load-induced pressure entering via line 123 and when the load-induced pressure exceeds the predetermined pressure, torque valve 60 will shift into the opposite direction.
• the operator merely waits until the auxiliary or whip hoist is in the in-haul mode. The operator then places the normal crane hoist control on the in-haul position and returns the emergency release handle to its normal position. Transition to a normal operation under these conditions is designed to be smooth and to function without problems. If the operator places the crane control system into the emergency release mode, that is by repositioning hand operated detented valve 21, and if during the operation of the crane in the emergency release mode a loss of control pressure occurs, as for example from loss of the prime mover, the diesel engine, or failure or loss of power due to the failure of one of the hydraulic components e.g.
• Shifting directional control valve 42 to its right hand position insures that the load-induced pressure that is directed from auxiliary or whip hoist motor 45 via line 117 will be blocked.
• the repositioning of three-position directional control valve 37 to the right hand port allows a load-induced flow coming via line 117 into directional control valve 37 to enter line 116 r which directs the pressure to directional control valve 35.
• Pressure from line 90 splits into two sections and directs the pressure to the lower pilot ports of directional control valves 58, 59, and the pilot port of valve 61, should power return. If power does return then the directional control valves 58 and 59 are positioned to respond to the increased or reactivated pressure which would then flow as before to the swash plate of the hoist pump, valve 61 is. positioned such that normal crane, control functions remain locked out.
• each of the three flow control valves 31, 32 and 33 used in the release mode without constant tension are installed with a fixed flow and are pressure and temperature compensated to limit the maximum speed that the auxiliary or whip hoist drum is capable of paying out, (paying out only in this instance, since there is no capability for controlling inhaul due to the loss of hydraulic power).
• line 92 is connected to directional control valve 28, which is normally open and hence to the pilot port of relief valve 26, thus activating relief valve 26. Further, line 92 is connected to the auxiliary or whip brake 47 thru line 93 and shuttle valves 49 and 50, thus maintaining pressure on auxiliary or whip brake 47, and keeping the brake in the release mode.
• auxiliary or whip hoist line In this emergency release mode without constant tension the auxiliary or whip hoist line is free to pay out as necessary, and this is dictated by the load, and it will continue to pay out until either the auxiliary or whip hoist line is stripped from the drum or the operator deactivates the emergency release mode by simply returning the emergency release control handle and hence the detented directional control valve 21 to its original position.
• This deactivation eliminates pressure to the hoist brake and causes the brake to set, stopping pay out.
• a high pressure relief valve 34 has been installed in the circuit to allow for momentary payout speeds in excess of the speeds set and normally limited by the flow control valves 31, 32 and 33.
• Relief valve 40 is activated when the operator selects the emergency release mode. hen the load-induced flow and pressure in line 17 exceeds the relief valve 40 setting excess flow generated by the auxiliary or whip hoist motor acting as a pump will flow through relief valve 40 and discharge directly into line 86 thru check valve
• the hydraulic control system of the present invention also includes an emergency shut-down control system.
• This emergency shutdown control is designed to completely shut the engine
• the emergency shut-down is designed such that it automatically sets all of the brakes in the event of an electrical power failure.
• the non-powered load lowering or either of the emergency release system has been activated, only those systems not part of these emergency systems will be affected.
• the shut-down control is mechanically attached through a push pull cable and suitable linkage to a flapper valve on the engine air intake.
• the flapper valve is provided as standard equipment on all diesel engines, such as those used on the Skagit cranes. However, if other engines are employed in other types of cranes, then similar valves or other devices could be employed to effect the same result.
• the flapper valve on the Skagit diesel engine must be physically reset at the engine after emergency shut-down is -activated in order to restart the engine.
• the electrical switch is connected to a solenoid valve which is located in the crane's hydraulic control circuit.
• the solenoid valve is also a part of the crane's hydraulic system along with the other emergency shut-down systems and is positioned as shown in figure 7. Pilot oil is supplied from line 103 via line 163 thru energized solenoid valve 200 to line 129 thru valve 61 to the operator control 66.
• the emergency shut-down system is available for use with or without either of the two modes of the emergency release systems or the two modes of the emergency non-powered load lowering systems.
• the preferred mode is that the hydraulic control cirucit for the crane include all three of said circuits to maximize the safety of the crane.
• the above described hydraulic control circuit is but one embodiment of the type of fluid control circuit where such feautures as the emergency release with constant tension and the emergency non-powered load lowering system, particularly for use with a crane hoist or -a crane device, could be used.
• various fluid control systems could be use with similar results for appropriate applications.
• similar emergency control circuits could be used employing the benefits of the emergency release with constant tension system and the emergency non-powered

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Control And Safety Of Cranes (AREA)
• Fluid-Pressure Circuits (AREA)

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• 1984
  • 1984-02-03 EP EP84400241A patent/EP0118340A3/de not_active Withdrawn
  • 1984-02-03 AU AU24067/84A patent/AU2406784A/en not_active Abandoned
  • 1984-02-03 WO PCT/US1984/000152 patent/WO1984003084A1/en unknown

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