JP2006232465A - Balance type crane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate generation of rapid motion on an arm of a crane even when a worker erroneously operates an operation part of the crane in a balance type crane. <P>SOLUTION: When the worker leaves the hand from a returning type push button SW29 during pressing operation by any cause, feeding of primary air of high pressure fed out from an air stop control valve 47 to the other entrance of an AND valve 75 is stopped. Therefore, since feeding out of a pilot pressure from the AND valve 75 to an air feeding stop valve 77 is stopped, feeding of air from the air feeding stop valve 77 to an air cylinder 79 is also shut-off. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a balanced crane that transports an object to be transported using a fluid pressure such as air pressure as a driving source.

In general, a balanced crane hangs a load on a tip of a movable arm extending in a horizontal direction from a main body mechanism attached to a support column, and uses a hydraulic cylinder (for example, an air cylinder) as an actuator to move the load from a certain place to a desired place. To be transported. That is, the operator grasps the handle portion at the tip of the movable arm and operates the operation portion of the handle portion, so that a predetermined air pressure is supplied from the fluid pressure circuit (for example, a pneumatic circuit, hereinafter referred to as a pneumatic circuit) of the body mechanism. When the air cylinder is supplied, a lifting force is generated in the movable arm, whereby the movable arm moves up in a state where a load is hung on the lifting tool of the handle portion. When an operator lowers the air pressure supplied to the air cylinder by operating the operation unit after rotating the movable arm in the horizontal direction and moving the load above a desired location, the load on the load is reduced. The movable arm moves down. Thereby, a load can be conveyed to a desired position (for example, refer nonpatent literature 1).
http://www.toyokoken.co.jp/products/p_04/02denki/01_bmes.htm

  By the way, in the conventional balanced crane having the above-described configuration, when the operator accidentally switches the pressure of the air supplied from the pneumatic circuit to the air cylinder from the high pressure to the low pressure in a state where the load is lifted by the arm provided in the crane. As a result, there is a possibility that the arm suddenly falls with the load on it. On the contrary, when the operator accidentally switches the pressure of the air supplied from the pneumatic circuit to the air cylinder from the low pressure to the high pressure without the luggage being loaded on the arm, the arm is thereby loaded with the luggage. Therefore, there is a risk that the ascending operation suddenly occurs.

  Therefore, in view of the above, a balanced crane has been proposed that includes a mechanism that makes an emergency stop of the cylinder operation when an abrupt operation occurs in the air cylinder.

  In the balanced crane according to the proposal, when the arm suddenly lifts or falls suddenly, the emergency stop mechanism is activated to stop the sudden movement of the arm. However, it is also assumed that an operator who is surprised by the sudden movement of the arm will release the emergency stop mechanism in a reflexive manner in an attempt to stop the sudden movement. When the mechanism is released, this causes a problem that the rapid movement of the arm resumes.

  Accordingly, an object of the present invention is to prevent a sudden movement of the crane arm even if an operator erroneously operates the operation section of the crane in a balanced crane.

  A balanced crane according to the present invention includes a fluid pressure actuator (79) for generating an upward force on a movable arm (5) supported so as to be swingable in a vertical direction, and a fluid pressure supply source (81). A pressure regulating valve (55) provided in a circuit connected to the fluid pressure actuator (79), for adjusting the fluid pressure supplied from the fluid pressure supply source (81) to a predetermined pressure and outputting the fluid pressure; The pressure regulating valve (55) and the fluid pressure actuator (79) are interposed between the pressure regulating valve (55) and the fluid pressure actuator (79) to open / close. When the first control valve (77) is controlled to open, the first control valve (77) is opened, and the fluid pressure in the fluid pressure actuator (79) is adjusted to the pressure regulating valve (55). When the pressure is released and the pressure is released by the first control valve 77) was closing operation comprises a configured operating switch mechanism (47) so as to close the fluid in the fluid pressure actuator (79).

  In a preferred embodiment according to the present invention, the pilot pressure output through the operation switch mechanism (47) between the operation switch mechanism (47) and the first control valve (77) is the first pressure. Is connected by a circuit for outputting to the control valve (77).

  In another embodiment, the pilot pressure circuit is configured to control the opening / closing operation of the first control valve (77) by the pilot pressure output through the operation switch mechanism (47). A second control valve (75) is further provided.

  In an embodiment different from the above, the operation switch mechanism (47) includes the fluid pressure supply source (81), the first control valve (77), or the second control valve (75). Including a mechanical valve (51) interposed therebetween.

  In an embodiment different from the above, the fluid pressure output from the mechanical valve (51) when the mechanical valve (51) is pressed is supplied to the second control valve (through the pilot pressure circuit). 75), the first control valve (77) is opened through the second control valve (75), and the fluid pressure is applied to the second control valve (75) by releasing the pressure. When the output is interrupted, the first control valve (77) is closed through the second control valve (75).

  In an embodiment different from the above, between the fluid pressure supply source (81) and the second control valve (75), the fluid pressure from the fluid pressure supply source (81) is changed between the second pressure control source (81) and the second control valve (75). The control valve (75) is connected by a circuit for output, and the circuit is opened only when the fluid pressure from the fluid pressure supply source (81) is equal to or higher than a predetermined pressure. Is further provided to the second control valve.

  In another embodiment, the second control valve (75) is configured such that the fluid pressure from the fluid pressure supply source (81) is equal to or higher than a predetermined pressure and the mechanical valve (51) is pressed. Thus, the AND valve outputs fluid pressure for opening the first control valve (77) only when fluid pressure is output from the mechanical valve (51).

  Moreover, in the balance type crane which concerns on embodiment different from the above, the upward biasing force is provided to a suspended load and the said suspended load can be moved manually.

  Furthermore, in another embodiment different from the above, air pressure is used as the fluid pressure.

  According to the present invention, in a balanced crane, even if an operator mistakenly operates the operation part of the crane, it is possible to prevent a sudden movement of the crane arm.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a side view showing the appearance of a balanced crane (hereinafter simply referred to as “crane”), which is a type of crane according to an embodiment of the present invention.

  As shown in FIG. 1, the crane includes a column 1, a crane main body (hereinafter simply referred to as “main body”) 3, a first arm 5, a parallel rod 7, and a second arm 9. And a handle portion, that is, a third arm 11.

  The support column 1 is fitted with a base 13 for erecting the support column 1 in a vertical direction with respect to an installation surface such as a floor surface of a work place on the lower end side, and the main body 3 is mounted on the upper end portion thereof. The air supply port 15 is provided near the upper end portion. The base 13 is formed so that the shape viewed from both side surfaces thereof and the shape viewed from the front and back surfaces thereof have a substantially trapezoidal shape, and has a rectangular hole at the center in the vertical direction. And in the state which the support | pillar 1 was inserted and inserted in this hole, the bottom part is attached and fixed to the floor surface etc. of a work place via fastening members (not shown), such as a plurality of sets of bolts and nuts.

  The air supply port 15 communicates with a pneumatic circuit (not shown here) built in the main body 3, and is connected to the high-pressure air source 81 to thereby supply high-pressure air supplied from the high-pressure air source 81. Is guided to the pneumatic circuit (not shown). A primary air supply unit 33 shown in FIG. 2 is provided at a portion of the support column 1 near the air supply port 15.

  The main body 3 is pivotally supported at the upper end of the support column 1 so as to be freely rotatable forward / reversely in the horizontal direction within an angle range regulated by a θ-axis turning stopper 17 provided at the upper end. The part 3 supports the first arm 5 and the parallel rod 7 so as to be swingable in the vertical direction (vertical direction) as shown in the figure. The main body 3 incorporates the above-described air circuit (not shown) and an air cylinder (not shown here). The air circuit (not shown) receives the high-pressure air supplied from the high-pressure air source 81 through the air supply port 15 and controls the driving of the air cylinder (not shown). The configuration and operation of the pneumatic circuit (not shown) will be described in detail with reference to FIG.

  The air cylinder (not shown) functions as an actuator of the first arm 5, and a piston (not shown) inside the air cylinder (not shown) is so-called reciprocating operation by the air pressure from the pneumatic circuit (not shown). By doing so, the first arm 5 is swung in the vertical direction.

  The first arm 5 and the parallel rod 7 are pivotally supported at their base end portions so as to be pivotable toward the main body portion 3 side, and the respective distal end portions are pivotally supported at the link member 19 as pivotable. Has been. That is, a parallel link is formed. Accordingly, the first arm 5 and the parallel rod 7 are integrally swung in the vertical direction by an air cylinder (not shown) while maintaining a parallel space therebetween via the link member 19.

  The second arm 9 is pivotally supported on the base end side of the second arm 9 via the attachment member 21 via the mounting member 21 so as to be able to rotate forward / reversely in the horizontal direction, and the third arm, The handle portion 11 is pivotally supported via a mounting member 23 so as to be freely rotatable forward / reversely in the horizontal direction. As shown in FIG. 1, the second arm 9 is swung in the vertical direction by the first arm 7 and the parallel rod 9 in a state that is always parallel to the installation surface of the crane.

The handle portion 11 includes a grip portion 25 for an operator (not shown) to grip, and the main body 3 described above.
A toggle lever (switching lever) 27 for operating a pneumatic circuit (not shown) built in the vehicle, a return type push button switch (hereinafter simply referred to as “push button SW”) (safety button) 29, And a hanging tool 31 for hanging a load to be transported. For example, a turn head broach, a cutting head used for a milling machine for machining the outer peripheral surface of a crankshaft of an internal combustion engine, etc. (not shown) Is mentioned. The handle portion 11 is provided with an air pressure switching portion 35 shown in FIG.

  FIG. 2 is a diagram illustrating a configuration of a pneumatic circuit provided in a crane according to an embodiment of the present invention.

  As shown in FIG. 2, the pneumatic circuit includes a primary air supply unit 33, a pneumatic switching unit 35, and a pneumatic pressure adjustment / output unit 37.

  As described above, the primary air supply unit 33 is provided in the vicinity of the air supply port 15 of the support column 1 shown in FIG. 1 and introduces high-pressure air from the high-pressure air source 81. The primary air supply unit 33 includes a filter 39, a pressure regulating valve 41, and a pressure gauge 43. The filter 39 removes dust contained in the high-pressure air supplied from the high-pressure air source 81 via the connection port (that is, the air supply port) 15 and sends the dust to the pressure regulating valve 41. The pressure regulating valve 41 receives high-pressure air supplied through the filter 39, adjusts the pressure of the air to a predetermined pressure (decompression), and then sends the air to the air pressure adjustment / output unit 37 side through the main line.

  As described above, the air pressure switching unit 35 is provided on the third arm shown in FIG. 1, that is, the handle unit 11, and includes the air pressure switching valve 45 and the air stop control valve 47. The pneumatic switching valve 45 is attached to the handle portion 11 and a two-stage switching type three-port two-position switching valve (hereinafter simply referred to as “switching valve”) 49 having two positioning portions as shown in the figure, for example. And a switching lever (toggle lever) 27 for the operator to switch the switching valve 49.

  The switching valve 49 sends high pressure primary air supplied from the primary air supply unit 33 through the main pipeline as a pilot pressure to the high / low pressure setting switching valve 69 on the air pressure adjustment / output unit 37 side through the pilot pipeline. When the switching lever 27 is switched to the high pressure side by the operator, the switching valve 49 sends high pressure air to the air pressure adjustment / output unit 37 side through the pilot line, and when the switching lever 27 is switched to the low pressure side, Air in the pilot line to the low pressure setting switching valve 69 is released to the atmosphere.

  The air stop control valve 47 includes, for example, a spring offset human-powered three-port two-position switching valve (hereinafter simply referred to as “switching valve”) 51 and a return-type pusher attached to the handle portion 11 as shown in the figure. And button SW29. The switching valve 51 sends high pressure primary air supplied from the primary air supply unit 33 through the main pipeline as a pilot pressure to the other inlet of the AND valve 75 of the air pressure adjustment / output unit 37 through the pilot pipeline. The return type push button SW29 is a so-called off return type push button SW, and moves the switching valve 51 in the direction opposite to the biasing force of the spring only when being pressed by the operator. That is, the switching valve 49 uses the high-pressure air supplied from the primary air supply unit 33 through the main pipeline as a pilot pressure only when the return-type push button SW29 is pressed by the operator, through the pilot pipeline ( It is sent to the other inlet of the AND valve 75). When the return type push button SW29 is released, the air in the pilot line connected to the other inlet of the AND valve 75 is released from the switching valve 51 to the atmosphere.

  As described above, the air pressure adjustment / output unit 37 is built in the main body 3 shown in FIG. The air pressure adjusting / output unit 37 includes a check valve 53, a pilot control pressure adjusting valve 55, flow rate adjusting valves 57, 59, 73 with check valves, a primary air pressure check valve 61, a high pressure setting pressure adjusting valve 63, A low pressure setting pressure regulating valve 65, a pressure gauge 67, a high / low pressure setting switching valve 69, an OR valve 71, an AND valve 75, and an air supply stop valve 77 are provided. When high-pressure air is supplied as pilot pressure from an OR valve 71, which will be described in detail later, through the flow regulating valves 57 and 59 with check valves, the pilot control pressure adjustment valve 55 supplies primary air through the main line and the check valve 53. The high-pressure air that regulates the primary air supplied from the section 33 side to a predetermined pressure is sent to the air supply stop valve 77 through the main line. The pilot control pressure regulating valve 55 is also connected to the primary air supply unit 33 through the main line and the check valve 53 when low pressure air is supplied as a pilot pressure from the OR valve 71 through the flow rate adjusting valves 57 and 59 with check valves. The low-pressure air regulated to the predetermined pressure from the primary air supplied from the air is sent to the air supply stop valve 77 through the main line.

  The high-pressure setting pressure regulating valve 63 sends high-pressure air that regulates the primary air supplied from the primary air supply unit 33 through the main line to a predetermined pressure to the high / low-pressure setting switching valve 69 through the main line.

  The high / low pressure setting switching valve 69 employs, for example, a spring offset pilot type three-port two-position switching valve as shown in the figure. The high / low pressure setting switching valve 69 is a high pressure setting pressure regulating valve that resists the biasing force of the spring only when the air pressure regulated to a relatively high pressure is sent from the air pressure switching valve 45 through the pilot line as a pilot pressure. By connecting the 63 side and the OR valve 71 side, high pressure air supplied from the high pressure setting pressure regulating valve 63 side is sent to one inlet of the OR valve 71. When the air is released from the air pressure switching valve 45 to the atmosphere through the pilot line, the high / low pressure setting switching valve 69 allows communication between the high pressure setting pressure regulating valve 63 side and the OR valve 71 side by the biasing force of the spring. Be blocked.

  The low-pressure set pressure regulating valve 65 sends low-pressure air, which is regulated to a predetermined pressure from the primary air supplied from the primary air supply unit 33 through the main pipeline, to the other inlet of the OR valve 71 through the main pipeline.

  As is clear from the above description, only when the high / low pressure setting switching valve 69 communicates with the high pressure setting pressure regulating valve 63 side and one inlet of the OR valve 71 at one inlet of the OR valve 71. High-pressure air is supplied from the high-pressure setting pressure regulating valve 63 side. On the other hand, the low pressure air is always supplied to the other inlet of the OR valve 71 from the low pressure setting pressure regulating valve 65 side. The OR valve 71 uses the high-pressure air as a pilot pressure when high-pressure air is supplied to the one inlet, and the low-pressure air when low-pressure air is supplied only to the other inlet. Air is supplied as pilot pressure to the flow rate control valves 59 and 57 with check valves and the pilot control pressure regulating valve 55 through the pilot line.

  As the primary side air pressure check valve 61, for example, as shown in the figure, a spring offset pilot type 5-port 2-position switching valve is employed. The primary air pressure check valve 61 adjusts the air pressure of the primary air to the flow regulating valve 73 with a check valve only when the air pressure of the primary air supplied from the primary air supply unit 33 through the main line is equal to or higher than a predetermined pressure value. To one inlet of the AND valve 75. That is, the primary air pressure check valve 61 is configured such that the pressure of the primary air supplied from the primary air supply unit 33 side through the pilot line and the main line is against the urging force of the spring, By connecting the non-return valve-equipped flow control valve 73 side, high-pressure air supplied from the primary air supply unit 33 side is sent to one inlet of the AND valve 75. The primary air pressure check valve 61 is configured such that when the pressure of the primary air supplied from the primary air supply unit 33 through the pilot pipe and the main pipe is below the biasing force of the spring, the biasing force of the spring This prevents communication between the primary air supply unit 33 side and the flow rate adjusting valve 73 side with a check valve. Then, the air in the pilot line between the primary air pressure check valve 61 and the AND valve 75 is released to the atmosphere.

  As apparent from the above description, the primary side air pressure check valve 61 is connected to one inlet of the AND valve 75 only when the flow rate adjusting valve 73 with check valve and the primary air supply unit 33 side communicate with each other. The primary air of a predetermined pressure is supplied as a pilot pressure through the primary air pressure check valve 61. Further, the other inlet of the AND valve 75 is primary through the pilot line, the air stop control valve 47, and the main line only when the operator presses the return push button SW29 of the air stop control valve 47. Primary air from the air supply unit 33 side is supplied as a pilot pressure.

  The AND valve 75 is supplied with primary air at a predetermined pressure through a flow regulating valve 73 with a check valve and a primary air pressure check valve 61 at one inlet, and through the air stop control valve 47 at the other inlet. Only when primary air of a predetermined pressure is supplied, a pilot pressure of a predetermined pressure is sent to the air supply stop valve 77.

  As the air supply stop valve 77, for example, as shown in the figure, a spring offset pilot type 5-port 2-position switching valve is employed. The air supply stop valve 77 is connected to the pilot control pressure regulating valve 55 side through the main line only when a pilot pressure of a predetermined pressure, that is, a pilot pressure larger than the urging force of the spring is supplied from the AND valve 75. The air cylinder with a silencer (hereinafter simply referred to as “air cylinder”) 79 communicates. Then, the primary air supplied from the primary air supply unit 33 side through the pilot control pressure regulating valve 55 is sent to the air cylinder 79.

  That is, when the high / low pressure setting switching valve 69 is set so that low pressure air is supplied from the OR valve 71 to the pilot control pressure regulating valve 55 as the pilot pressure, the low pressure setting pressure regulating valve 65 sets the predetermined pressure. The regulated low-pressure air is sent from the primary air supply unit 33 to the air cylinder 79 through the air supply stop valve 77. On the contrary, when the high / low pressure setting switching valve 69 is set so that high pressure air is supplied from the OR valve 71 side as the pilot pressure to the pilot control pressure regulating valve 55, the high pressure setting pressure regulating valve 63 High-pressure air regulated to a predetermined pressure is sent from the primary air supply unit 33 to the air cylinder 79 through the air supply stop valve 77.

  The case where low-pressure air is supplied from the air supply stop valve 77 to the air cylinder 79 is, for example, a case where no load is hung on the hanging tool 31 shown in FIG. The case where high-pressure air is supplied to the cylinder 79 is a case where a load is hung on the hanging tool 31.

  As described above, the air cylinder 79 is built in the main body 3 shown in FIG. 1 together with the air pressure adjustment / output unit 37, and is supplied with high-pressure or low-pressure air supplied through the air supply stop valve 77. As a result, the piston reciprocates. When the operator raises and lowers the load, the piston reciprocates through the first arm 5. When the piston reciprocates, the volume of air in the air cylinder 79 changes, and the air pressure fluctuates as it is. Since the fluctuation of the air pressure leads to a change in the upward biasing force applied to the load, a smooth crane operation cannot be performed. Therefore, the pilot control pressure regulating valve 55 functions to keep the air pressure in the air cylinder 79 at a predetermined pressure.

  Next, the operation of each part in the pneumatic circuit having the above configuration will be described.

  When the operator operates the switching lever 27 to set the switching valve 49 to the high pressure side, the high pressure primary air regulated to a predetermined pressure in the high pressure setting pressure regulating valve 63 is converted into the high / low pressure setting switching valve 69, The pilot pressure is sent to the pilot control pressure regulator 55 through the OR valve 71 and the like. The pilot control pressure regulating valve 55 regulates the primary air pressure to a predetermined pressure based on the pilot pressure, and sends the regulated high-pressure air to the air supply stop valve 77.

  Further, when the operator operates the switching lever 27 to set the switching valve 49 to the low pressure side, the air at one inlet of the OR valve 71 is released to the atmosphere in the high / low pressure setting switching valve 69. Therefore, the low pressure primary air regulated to a predetermined pressure in the low pressure setting pressure regulating valve 65 is sent to the pilot control pressure regulating valve 55 as a pilot pressure through the OR valve 71 and the like. The pilot control pressure regulating valve 55 regulates the primary air pressure to a predetermined pressure based on the pilot pressure, and sends the regulated low-pressure air to the air supply stop valve 77.

  When the return push button SW29 is pressed, high pressure primary air is sent from the air stop control valve 47 to the other inlet of the AND valve 75 as a pilot pressure. In this case, if primary air equal to or higher than a predetermined pressure value is sent from the primary side air pressure check valve 61 to the one inlet of the AND valve 75 as a pilot pressure, the AND valve 75 supplies the air supply stop valve 77. Pilot pressure is supplied. Therefore, the pilot control pressure regulating valve 55 and the air cylinder 79 are communicated with each other via the air supply stop valve 77.

  However, if the operator releases his / her hand from the return-type push button SW29 during the pressing operation for some reason, the high pressure that has been sent from the air stop control valve 47 to the other inlet of the AND valve 75 is thereby released. Primary air supply is interrupted. For this reason, since the pilot pressure is not sent from the AND valve 75 to the air supply stop valve 77, the pneumatic circuit between the pilot control pressure regulating valve 55 and the air cylinder 79 is cut off.

  Therefore, in the crane having the above-described configuration, when the switching operation of the air pressure supplied to the air cylinder is mistaken, the worker who notices it loses the normality, and the handle portion 11 that has been gripped up to that time is conditionally reflected. It is assumed that they will be separated. For this reason, the supply of the high-pressure primary air that has been sent from the air stop control valve 47 to the other inlet of the AND valve 75 is interrupted, whereby the air in the air cylinder 79 is blocked and the arm is closed. It has become possible to prevent a sudden drop / rise operation.

  FIG. 3 is a diagram illustrating a configuration of a pneumatic circuit provided in a crane according to another embodiment of the present invention.

  The pneumatic circuit provided in the crane according to the present embodiment is different from the pneumatic circuit shown in FIG. 2 in the configuration described below. That is, in the present embodiment, as shown in FIG. 3, the AND valve 75 shown in FIG. 2 constitutes an air stop control valve 47A on the air pressure switching unit 35 side on the air pressure adjustment / output part 37 side. The main pipelines required for the connection between the spring offset human-powered three-port two-position switching valve (hereinafter simply referred to as “switching valve”) 51A and the primary air supply unit 33 are removed. A flow rate adjusting valve 73 with a check valve on the air pressure adjustment / output unit 37 side and a switching valve 51A (on the air pressure switching unit 35 side) are directly connected through the pilot line, and the air pressure adjustment / output is connected to the switching valve 51A. The air supply stop valve 77 on the side of the section 37 is directly connected through the pilot pipe line.

  In other words, the switching valve 51A has a pilot pressure of a predetermined pressure, that is, a magnitude exceeding the urging force of the spring of the air supply stop valve 77 in a state where the return-type push button SW29 is pressed by the operator. Pilot pressure is supplied to the air supply stop valve 77 through the pilot line. However, this pilot pressure does not use high-pressure primary air supplied from the primary air supply unit 33 through the main pipe as a pressure source, but a pilot pressure supplied through the flow regulating valve 73 with a check valve and the pilot pipe. The pressure is used as a pressure source.

  Since the configuration other than the above is the same as the configuration shown in FIG. 2, in FIG. 3, the same components as those shown in FIG. Omitted.

  In the above configuration, when the operator releases his / her hand from the return-type push button SW29 that is being pressed for some reason during the work, the air stop control valve 47A thereby sends the air to the air supply stop valve 77. The supply of pilot pressure is interrupted. Therefore, the air supply stop valve 77 closes the main pipeline connecting the pilot control pressure regulating valve 55 and the air cylinder 79 by the action of the urging force of the spring.

  Therefore, also in this embodiment, when the switching operation of the air pressure supplied to the air cylinder is mistaken, the operator who notices it loses the normality, and the handle portion 11 that has been gripped so far is conditionally reflected. Even in such a case, the air in the air cylinder 79 is blocked and the arm can be prevented from suddenly dropping / raising.

  The preferred embodiments of the present invention have been described above, but these are merely examples for explaining the present invention, and the scope of the present invention is not limited to these embodiments. The present invention can be implemented in various other forms. For example, in each embodiment of the present invention, an air cylinder and a pneumatic circuit for supplying a predetermined air pressure to the air cylinder are used as the arm actuator. However, as the arm actuator, a hydraulic cylinder and a hydraulic cylinder are used. A hydraulic circuit that supplies a predetermined hydraulic pressure may be used, or a mechanism that uses fluid pressure other than air pressure and hydraulic pressure may be used as an actuator for the arm.

The side view which shows the external appearance of the balance type crane which is 1 type of the crane which concerns on one Embodiment of this invention. The figure which shows the structure of the pneumatic circuit with which the balance type crane which is 1 type of the crane which concerns on one Embodiment of this invention is provided. The figure which shows the structure of the pneumatic circuit with which the balance type crane which is 1 type of the crane which concerns on other embodiment of this invention is provided.

Explanation of symbols

1 Prop 3 Crane body (main body)
5 First arm 7 Parallel rod 9 Second arm 11 Third arm (handle portion)
13 Base 15 Air Supply Port 17 θ Axis Turning Stopper 19 Link Member 21, 23 Mounting Member 25 Grip Part 27 Switching Lever (Toggle Lever)
29 Return-type pushbutton switch (SW)
31 Lifting tool 33 High pressure air source introduction part 35 Air pressure switching part 37 Air pressure adjustment / output part 39 Filter 41 Pressure regulating valve 43, 67 Pressure gauge 45 Air pressure switching valve 47 Air stop control valve 53 Check valve 55 Pilot control pressure regulating valve 57, 59 , 73 Flow control valve with check valve 61 Primary air pressure check valve 63 High pressure setting pressure regulating valve 65 Low pressure setting pressure regulating valve 69 High / low pressure setting switching valve 71 OR valve 75 AND valve 77 Air supply stop valve 79 Air cylinder 81 High pressure air source

Claims (9)

A fluid pressure actuator (79) for generating an upward force on a movable arm (5) supported so as to be swingable in a vertical direction;
A pressure regulating valve that is provided in a circuit that connects the fluid pressure supply source (81) and the fluid pressure actuator (79), and adjusts and outputs the fluid pressure supplied from the fluid pressure supply source (81) to a predetermined pressure. (55)
The circuit is interposed between the pressure regulating valve (55) and the fluid pressure actuator (79), and opens / closes communication between the pressure regulating valve (55) and the fluid pressure actuator (79). A first control valve (77) controlled by closing operation;
When the pressure is pressed, the first control valve (77) is opened, and the fluid pressure in the fluid pressure actuator (79) is maintained at a predetermined pressure by the pressure regulating valve (55). An operation switch mechanism (47) configured to close one control valve (77) and close the fluid in the fluid pressure actuator (79);
Balanced crane with The balanced crane according to claim 1,
Between the operation switch mechanism (47) and the first control valve (77), the pilot pressure output through the operation switch mechanism (47) is output to the first control valve (77). Balanced crane connected by a circuit. The balanced crane according to claim 2,
The pilot pressure circuit includes a second control valve (75) for controlling the opening / closing operation of the first control valve (77) by the pilot pressure output through the operation switch mechanism (47). A balanced crane. The balanced crane according to any one of claims 1 to 3,
The operation switch mechanism (47) includes a mechanical valve (51) interposed between the fluid pressure supply source (81) and the first control valve (77) or the second control valve (75). Including balanced crane. The balanced crane according to claim 4,
The fluid pressure output from the mechanical valve (51) when the mechanical valve (51) is pressed is output to the second control valve (75) through the pilot pressure circuit. The first control valve (77) is opened through the control valve (75), and the output of the fluid pressure to the second control valve (75) is interrupted by releasing the pressure, whereby the second control A balanced crane configured to close the first control valve (77) through a valve (75). In the balance type crane according to any one of claims 3 to 5,
Between the fluid pressure supply source (81) and the second control valve (75), the fluid pressure from the fluid pressure supply source (81) is output to the second control valve (75). A first circuit that opens and outputs the fluid pressure to the second control valve only when the fluid pressure from the fluid pressure supply source (81) is equal to or higher than a predetermined pressure. A balanced crane further comprising three control valves (61). The balanced crane according to claim 6, wherein
The second control valve (75) is configured such that the fluid pressure from the fluid pressure supply source (81) is equal to or higher than a predetermined pressure and the mechanical valve (51) is pressed. A balanced crane that is an AND valve that outputs a fluid pressure for opening the first control valve (77) only when a fluid pressure is output from the first control valve (77). The balanced crane according to claim 1, wherein an upward biasing force is applied to the suspended load, and the suspended load can be moved manually. The balanced crane according to claim 1,
A balanced crane in which air pressure is used as the fluid pressure.

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