JP2003002583A - Expansion mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten total time required to bring the whole extension boom to a target expansion condition, in an expansion mechanism using one expansion cylinder. SOLUTION: This mechanism is constituted to be switched between an ordinary expansion oil passage 136 wherein a space between an extension side oil chamber 131 of the expansion cylinder and the first outlet port 132 of an expansion operation selector valve 103 communicates with an extension side oil passage 130, wherein a differential selector valve 133 is interposed between a contraction side oil passage 134 of the expansion cylinder and the second outlet port 135 of the selector valve 103, and which makes the contraction side oil passage 134 of the expansion cylinder communicate with the second outlet port 135 of the selector valve 103 by switching the differential selector valve 133, and a differential extension oil passage 137 for communicating the contraction side oil passage 134 of the expansion cylinder with the first outlet port 132 of the expansion operation selector valve 103.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive hydraulic circuit for a telescopic cylinder of an telescopic mechanism that telescopically drives a boom stage that constitutes a multi-stage telescopic boom by one telescopic cylinder.

[0002]

2. Description of the Related Art As a telescopic mechanism for a multi-stage telescopic boom of a vehicle-mounted crane, an telescopic mechanism has been put into practical use in which a boom stage to be telescopically driven by one telescopic cylinder is telescopically driven. Since this telescopic mechanism has only one telescopic cylinder, it has the advantage that the weight of the entire telescopic mechanism can be reduced.

In this telescopic mechanism, one telescopic cylinder is installed in the telescopic boom, and the rod end is pivotally supported by the base boom base end. The expansion / contraction mechanism has a unique structure including a cylinder / boom connecting means, a boom-to-boom fixing means, and a fixing pin driving means.

The cylinder-boom connecting means is arranged at the rod-side end of the cylinder tube of the telescopic cylinder, and is selected by advancing and retracting the built-in connecting pin toward the connecting hole at the base end of the desired boom. It can be connected / disconnected to the boom base end.

The boom-to-boom fixing means is arranged at the inner boom base end portion of the adjacent booms, and the built-in fixing pins are moved toward and away from the fixing holes provided at appropriate positions of the outer booms so that the adjacent booms are adjacent to each other. Can be fixed and released.

The fixed pin driving means is arranged at the end portion of the telescopic cylinder on the cylinder tube rod side, and acts on the inner end of the fixed pin at the base end portion of the boom to drive it forward and backward.

Then, a cylinder-boom connecting process for connecting the telescopic cylinder and a target boom base end portion by the cylinder-boom connecting means, and a target boom and an outer boom by the boom-to-boom fixing means by the fixing pin driving means. Between the booms for releasing the fixation of the boom between the booms for releasing the fixation of the boom between the boom and the boom for fixing the boom between the boom and the outside boom by the fixing pin drive means. A fixed stroke, a cylinder / boom connection releasing stroke for releasing the connection between the telescopic cylinder and the target boom base end portion by the cylinder / boom connecting means, and an telescopic cylinder for the telescopic cylinder to extend / contract to the next target boom base end portion. The telescopic boom can be extended and retracted by repeating the following steps. It is.

[0008]

However, since the above-mentioned telescopic mechanism drives the boom stages to be telescopically driven by one telescopic cylinder one by one, only the telescopic cylinder is used during the above-mentioned telescopic stroke. Requires an extension / contraction cylinder extension / contraction process in which the boom stage is extended / reduced without performing extension / contraction drive, and the time required for this process is generated. Therefore, the total time required to bring the entire telescopic boom into the intended telescopic state is longer than that of the telescopic mechanism having a plurality of telescopic cylinders.

Therefore, the present invention intends to provide an expanding / contracting mechanism using a single expanding / contracting cylinder, which can shorten the total time required to bring the entire expanding / contracting boom into the desired expanding / contracting state. It is a thing.

[0010]

According to the invention described in claim 1 of the present application, the drive hydraulic pressure supply means for driving the telescopic cylinder that telescopes the telescopic boom is switched between the extension side oil chamber of the telescopic cylinder and the telescopic operation. An extension-side oil passage is connected to the first outlet port of the valve, and a differential switching valve is interposed between the contraction-side oil chamber of the telescopic cylinder and the second outlet port of the telescopic operation switching valve. Then, by switching the differential switching valve, the contraction-side oil chamber of the expansion cylinder and the normal expansion oil passage communicating with the second outlet port of the expansion-conversion operation switching valve, the compression-side oil chamber of the expansion cylinder and the It is characterized in that it can be switched to a differential expansion oil passage that communicates with the first outlet port of the expansion / contraction operation switching valve.

With this configuration, when the telescopic cylinder is extended by the differential extension oil passage, the amount of oil required for the extension is smaller than that required by the normal extension oil passage, so that the extension is required. The time is short. Therefore, it is possible to reduce the total time required to bring the entire telescopic boom into the desired telescopic state.

Further, in the invention described in claim 2 of the present application, in addition to the configuration described in claim 1, the telescopic mechanism control device further includes an telescopic boom hoisting angle detector, and the controller According to a detection signal from the telescopic boom hoisting angle detector, the differential switching valve is controlled to be switchable to the differential extension oil passage only when the telescopic boom has a predetermined hoisting angle or more. Is characterized by.

When the telescopic cylinder is differentially extended, the extension output is reduced as compared with the normal extension. Therefore, the extension operation is performed in a range where the boom hoisting angle in which the reaction force between the booms of the telescopic boom is large is small. Is not preferable. Therefore, according to the configuration of the invention described in claim 2, the telescopic cylinder can be differentially extended only when the boom hoisting angle that enables the extension operation by the differential extension oil passage is equal to or larger than a predetermined angle. .

Further, in the invention described in claim 3 of the present application, in addition to the configuration described in claim 1, the expansion mechanism control device further includes an expansion cylinder load detector, and the controller is The differential switching valve is controlled to be switchable to the differential extension oil passage only when the expansion cylinder has a load equal to or less than a predetermined load, based on a detection signal from the expansion cylinder load detector.

When the telescopic cylinder is differentially extended, the extension output is reduced as compared with the normal extension. Therefore, it is not preferable to perform the extension operation in a state where the load of the telescopic cylinder is large. Therefore, according to the configuration of the invention described in claim 3, it is possible to differentially extend the telescopic cylinder only when the telescopic cylinder capable of the extension operation by the differential extension oil passage has a predetermined load or less.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Telescopic machine with one telescopic cylinder
Configuration of Structure FIG. 1 is a cross-sectional view taken along the telescopic cylinder of a six-stage telescopic boom in which an telescopic mechanism including one telescopic cylinder is used, and shows a base end portion in a fully contracted state. Telescopic boom 10
Inside the base boom 11, the second boom 12, the third boom 13, the force boom 14, the fifth boom 1
5 and the top boom 16 are each telescopically inserted. Reference numeral 1 denotes a telescopic cylinder, which includes a cylinder tube 2, a cylinder tube rod side end portion 3,
It is composed of a rod 4 and a rod end portion 5. The telescopic cylinder 1 is installed in the telescopic boom 10, and the telescopic cylinder rod end 5 is pivotally supported by the base end 11 a of the base boom 11. The main configuration of the expansion / contraction mechanism including one expansion / contraction cylinder will be described below. (Cylinder / boom connecting means) FIG. 2 is a sectional view taken along line AA of FIG. 20 is a cylinder / boom connecting means,
Cylinder tube rod end 3 of the telescopic cylinder 1
Connecting pin drive cylinder 21, connecting pin drive lever 22, connecting pin 23, and connecting hole 16b of the connecting boss 16c arranged at the top boom base end 16a.
It consists of The connecting pin 23 is slidably assembled in the connecting pin receiving hole 26 of the trunnion member 25 that constitutes the end portion 3 of the telescopic cylinder rod side. The connecting pin drive lever 22 is pivotally supported from the trunnion member 25 to a support 24 integrally formed above. In FIG. 2, the connection hole 16b is the base boom base end portion 1
Although only those provided on 6a are shown, as indicated by the chain double-dashed line in FIG. 1, the second boom base end 12a, the third boom base end 13a, the force boom base end 14a, the fifth boom base end 15a, Similarly for each connection hole 1
2b, 13b, 14b, 15b are provided.

The connecting pin 23 and the connecting pin drive lever 2
A pair of 2 is arranged on the left and right. Connecting pin drive lever 2
One end of 2 is pivotally attached to the connecting pin 23, and the other end is pivotally attached to the rod end 21a and the cylinder end 21b of the connecting pin drive cylinder 21, respectively. (Connecting means between booms) 50 shown in FIG. 2 is the top boom 1
6 is a boom-to-boom connecting means, and is a top boom base end portion 1
The top boom fixing pin 16d and the fifth boom 15 slidably assembled to the fixing pin housing member 16e of 6a.
Fixing hole 5 provided in the fixing boss 52 attached to the side surface of the
1 and 1. Reference numeral 33 is a connecting member provided at the inner end of the top boom fixing pin 16d. The connecting member 33 has a box shape with a part of the opening, and can be connected to a fixed pin drive lever of a fixed pin drive means described later. As shown in FIG. 2, a pair of top boom fixing pins 16d are arranged on the left and right. Similarly, the second boom base end 12a and the third boom base end 1 (not shown)
Similarly, a pair of second boom fixing pin 12d, third boom fixing pin 13d, force boom fixing pin 14d, and fifth boom fixing pin 15d are arranged on the left and right sides of 3a, the force boom base end portion 14a, and the fifth boom base end portion 15a, respectively. There is.

In addition to the fixing boss 52 mounted on the side surface of the fifth boom, a plurality of fixing bosses are arranged on the side surface of the fifth boom in the longitudinal direction thereof in accordance with the extension length of the top boom 16. Each fixing boss has a fixing hole. Regarding the arrangement of the fixed boss, the base boom 11, the second boom 12, the third boom 1
3. The force boom 14 has almost the same configuration.

FIG. 3 is a view taken along the line BB of FIG. Reference numeral 34 is a ball lock mechanism of the fixing pin 16d. A notch 36 is formed in the fixing pin 16d, and the spring-biased ball 35 of the ball lock mechanism 34 is notched by the notch 36.
By being fitted into the fixing pin 16d, the end portion 53 of the fixing pin 16d is held at the fixed position between the booms where the fixing pin 16d enters the fixing hole 51 of the outer boom. (Fixed Pin Driving Means) Reference numeral 40 shown in FIG. 3 is a fixed pin driving means, which is composed of a fixed pin driving cylinder 41, a fixed pin driving lever 42, and a roller 44. The fixed pin drive lever 42 is a support 45 formed integrally with the end portion 3 of the telescopic cylinder 1 on the cylinder tube rod side.
Is swingably supported by a pair, and a left and right pair are arranged. A roller 44 is provided at one end of the fixed pin drive lever 42.
Is rotatably supported, and the other ends thereof are pivotally attached to the rod side end portion 41a and the cylinder side end portion 41b of the fixed pin drive cylinder 41, respectively.

The fixed pin drive means 40 is entirely integrated with the end portion 3 of the telescopic cylinder 1 on the cylinder tube rod side. Therefore, the fixing pins 12d to 16 of the boom-to-boom fixing means 50 and the like of the top boom 16 arranged at the base end portion of each stage boom by the expansion and contraction operation of the expansion and contraction cylinder 1.
The roller 44 can be positioned in the connecting member 33 of any fixed pin of d, and the fixed pin can be driven. At that time, when the telescopic cylinder 1 extends and contracts, the connecting member 33 provided at the inner end of the fixing pin has a box-like shape with an opening.
The fixing pin drive lever 42 can pass through the opening portion of the connecting member 33 of the fixing pin which is not intended. Configuration of Control Device for Extension Mechanism FIG. 4 shows a block diagram and a hydraulic circuit diagram of a control device for the extension mechanism according to the embodiment of the present invention. (Expansion / contraction mechanism operating means) 60 is an expansion / contraction mechanism operating means, and includes an expansion / contraction operating lever 61 and a final boom state input means 6
3. Comprised of expansion and contraction related information display means 70,
It is located in the crane cab (not shown). The expansion / contraction operation lever 61 converts the expansion / contraction operation lever operation amount into an electric signal and outputs it to the controller 65. The final boom state input means 63 is for inputting the final boom state when the telescopic boom 10 is telescopically extended by the telescopic mechanism, and is operated integrally with the telescopic related information display means 70 described later. is there. The operation signal of the final boom state input means 63 is also output to the controller 65. The expansion / contraction related information display means 70 graphically displays information related to the operation of the expansion / contraction mechanism in response to a signal from the controller 65.

The expansion / contraction related information display means 70 can switch the display contents, and FIG. 5 shows a display screen by the expansion / contraction related information display means 70. A plurality of extension lengths 71 of telescopic booms and boom extension ratios 72 of each stage of booms indicating the boom condition are displayed, and the box-shaped cursor 73 can be moved up and down by the feed / return key included in the final boom state input means 63. It is like this. When the set key included in the final boom state input means 63 is operated after moving the box-shaped cursor 73 to the line of the desired boom condition, the final boom state of the desired telescopic boom is input to the controller 65. be able to.
The selected last boom state is indicated by the circle mark 74. (Expansion / contraction state detecting means) 75 is an expansion / contraction state detecting means, and includes the following detecting means. That is, 8
Reference numeral 0 is a boom base end position detecting means,
It detects which boom the boom connecting means 20 is located at the base end position and outputs the signal to the controller 65. Reference numeral 90 denotes a cylinder length detecting means, which detects the cylinder length of the telescopic cylinder 1 and outputs a signal thereof to the controller 65. The controller 65 reads out the specified expansion / contraction length determined by the stored position of the fixing hole of the boom fixing means based on the detection value of the cylinder length detection means 90, and reads the specified expansion / contraction length from the boom. It is the length of expansion / contraction in the expansion / contraction process. Reference numeral 110 is a connecting pin state detecting means, which detects the state of the connecting pin driven by the cylinder / boom connecting means 20 and outputs a signal thereof to the controller 65. A fixed pin state detecting means 120 detects the state of the fixed pin driven by the fixed pin driving means 40 and outputs the signal to the controller 65.

FIG. 6 shows the boom base end position detecting means 80.
It is a specific example of FIG. 2, and is a DD arrow view of FIG. Proximity switches 82 to 86 are attached to the trunnion 25 located at the end portion 3 of the telescopic cylinder 1 on the cylinder tube rod side via the supports 81, 81. 1
6f is a detection piece attached to the base boom base end portion 16a. FIG. 6 shows a state in which the proximity switch 86 detects the detection piece 16f of the top boom base end portion 16a. Similarly, the proximity switch 82 is also attached to the other boom base end.
The detection pieces 12f to 15f are provided at positions corresponding to .about.85, and the proximity switches 82 to 85 detect the detection pieces, respectively. With this configuration,
Depending on which proximity switch detects the detection piece, it is possible to determine which boom the connecting pin 23 of the boom / cylinder connecting means 20 is located in the connecting hole of the base end portion of the boom.

FIG. 1 shows a state in which the cylinder length detecting means 90 is attached to the telescopic boom 10.
The cylinder length detecting means 90 is the base boom base end portion 11a.
The cord 91 pulled out from the length detector 95 is connected to the support 94 of the end portion 3 on the cylinder tube rod side of the telescopic cylinder 1 through the guide rollers 92 and 93. The cord 91 is moved in and out of the length detector 95 as the telescopic cylinder 1 extends and contracts, and the length of the telescopic cylinder 1 is detected by the amount of the cord 91 pulled out. ing.

FIG. 7 is a view taken along the line CC of FIG. 2, showing the details of the connecting pin state detecting means 110. Reference numerals 112 and 113 are proximity switches attached to the cylinder portion of the connecting pin driving cylinder 21.
Is a U-shaped detection piece attached to the rod portion of the connecting pin drive cylinder 21. In FIG. 2, the connecting pin 23 of the cylinder / boom connecting means has the connecting hole 16b of the top boom 16.
When the cylinder and the boom are in the connected state, the one proximity switch 112 detects the detection piece 111 at this time. The connecting pin drive cylinder 21 is driven, and the tip of the connecting pin 23 is connected to the connecting hole 1
Upon exiting from 6b, the other proximity switch 113 detects the detection piece 111.

Reference numeral 120 in FIG. 3 shows a specific example of the fixed pin detecting means. 122 and 123 are proximity switches attached to the cylinder portion of the fixed pin drive cylinder 41, and 121 is the connection pin drive cylinder 41.
It is a U-shaped detection piece attached to the rod part of. FIG. 3 shows the tip portion 5 of the fixing pin 16d of the base boom end portion 16a.
3 is in the state of releasing the fixation between the booms from the fixing hole 51 of the fifth boom 15, and at this time, the one proximity switch 123 detects the detection piece 121. When the fixed pin drive cylinder 41 is driven and the tip portion 53 of the fixed pin 16d enters the fixed hole 51, the other proximity switch 122 detects the detection piece 121. (Other Detectors) Reference numeral 140 shown in FIG. 4 is an overload prevention device, which is generally mounted on a vehicle-mounted crane. Detection signals from the telescopic boom hoisting angle detector 141, the telescopic boom length detector 142, and the telescopic boom moment detector 143 are input to the overload prevention device 140. The overload prevention device 140 calculates the telescopic cylinder load based on the input signal. The overload prevention device 1
From 40, signals of the telescopic boom hoisting angle and the telescopic cylinder load are output to the controller 65. (Drive hydraulic pressure supply means) 100 is a drive hydraulic pressure supply means, which receives a signal from the controller 65 and drives the telescopic cylinder 1, the cylinder / boom coupling means 20, and the fixed pin drive means 40 which constitute the telescopic mechanism. It is a thing.

FIG. 4 shows an example of a concrete hydraulic circuit which constitutes the driving hydraulic pressure supply means 100. The drive hydraulic pressure supply means 100 is an expansion / contraction cylinder 1, a pilot type switching valve 103 interposed between a counter balance valve 104 and a hydraulic pressure source, and a tank, and an electromagnetic proportional that sends a pilot pressure for switching the pilot type switching valve 103. Valve 10
1, 102 and a flow control valve 109. The solenoid proportional valves 101 and 102 are proportionally controlled by a signal from the controller 65.

Reference numeral 130 is an extension side oil passage that connects between the extension side oil chamber 131 of the telescopic cylinder 1 and the first outlet port of the pilot type switching valve 103. 133 is a reduction side oil chamber 134 of the telescopic cylinder 1 and the pilot type switching valve 1
03 is a hydro valve interposed between the third outlet port 135 and the second outlet port 135, and by switching the hydro valve 133, the reduction side oil chamber 134 of the telescopic cylinder 1 and the second of the pilot switching valve 103. The normal expansion / contraction oil passage 136 communicating with the outlet port 135, the reduction side oil chamber 134 of the expansion / contraction cylinder 1 and the first of the pilot type switching valve 103.
Can be switched to the working extension oil passage 137 that communicates with the outlet port 132 of the. 138 is the hydro valve 13
A solenoid switching valve for supplying / discharging the switching pilot pressure from the hydraulic pressure source 3 is adapted to be switched by a switching signal from the controller 65. The hydro valve 133 and the solenoid switching valve 138 constitute the differential switching valve described in claim 1.

The connecting pin drive cylinder 21 and the fixed pin drive cylinder 41 are respectively connected to the solenoid switching valve 10
Connected to the oil pressure source and the tank via 7, 108,
The solenoid switching valves 107 and 108 are the controller 6
Switching operation is performed by a signal from 5. Operation of the telescopic mechanism From the fully contracted state of the 6-step telescopic boom 10 shown in FIG.
Corresponding to the extension operation of the telescopic mechanism until the top boom 16 and the fifth boom 15 shown in FIG.
The control contents of the control device of the present invention will be described. (Boom condition setting) Telescopic boom 10 is in the fully contracted state,
The undulation angle is assumed to be the maximum undulation angle. At this time, as shown in FIG. 1, the cylinder / boom connecting means 20 is in a connected state with the base end portion 16b of the top boom 16, and all the boom-to-boom fixing means of each stage boom are in a fixed state. The boom condition is selected on the display screen of the expansion / contraction related information display means 70 shown in FIG. 5 by the feed / return key included in the final boom state input means 63. Now, let's say the top boom (6
The third stage) grew by 93%, and the fifth boom (fifth stage) was 9%
Suppose you have selected No. 5 boom condition, which grows by 3%. When the set key included in the final boom state input means 63 is operated, the selected boom condition is output to the controller 65 and stored in the controller 65. Next, as long as the telescopic operation lever 61 is operated to the extension side and the operation is continued,
Thereafter, the controller 65 automatically controls the telescopic mechanism, repeats the cycle of the telescopic mechanism, and continues the telescopic operation until the boom condition set above is satisfied. When the extension / contraction operation lever 61 is returned to the neutral position, the controller 65 stops the operation of the extension / contraction mechanism at that time. (Boom-to-boom fixing release process) The controller 65 outputs a signal for pulling out the fixing pin 16d to the fixing pin driving means 40.
Specifically, a signal is sent to the solenoid switching valve 108 of FIG. 4, the fixed pin drive cylinder 41 is driven, and the fixed pin 16d is moved to the extraction side. That is, when the fixed pin drive cylinder 41 of the fixed pin drive means 40 is extended, the fixed pin drive lever 42 swings, and the roller 44 positioned at one end of the fixed pin drive lever 42 moves inside the fixed pin 16d. It acts on the opening side 37 of the connecting member 33 located at the end. Then, the ball 35 of the ball lock mechanism 34 is pushed back by disengaging the notch 36 of the fixing pin 16d, and the tip portion 53 of the fixing pin 16d comes out of the fixing hole 51 of the fifth boom 15. As a result, the fixing between the top boom base end portion 16a and the fifth boom 15 by the boom fixing means 50 of the top boom 16 is released. (Boom expansion / contraction process) The fixing pin 16d of the boom-to-boom fixing means 50 of the top boom base end portion 16a and the fixing hole 51 of the fifth boom 15 are fixed by a signal from the fixing pin state detecting means 120 shown in FIG. When the release is confirmed, an extension signal is output from the controller 65 to the driving hydraulic pressure supply means 100, and the telescopic cylinder 1 is moved to the top boom 16.
The expansion operation of is started.

Specifically, at this time, the controller 6
5 receives signals of the telescopic boom hoisting angle and the telescopic cylinder load from the overload prevention device 140, the hoisting angle is equal to or greater than a predetermined angle, and the hoisting cylinder load is equal to or less than the predetermined load. Therefore, the solenoid switching valve 138 is used. The switching signal is output to. Then, the pilot pressure acts on the hydro valve 133 and the hydro valve is switched, so that the reduction side oil chamber 134 of the telescopic cylinder 1 and the pilot switching valve 1 are switched.
The first outlet port 132 of 03 is switched to the differential extension oil passage 137.

From the controller 65 of FIG. 4 to the solenoid proportional valve 1
A signal is output to 01, the pilot pressure is applied to the pilot-type switching valve 103 to switch the pilot type switching valve 103, and the telescopic cylinder 1 extends to extend the top boom 16.

At this time, since the expansion / contraction cylinder 1 is expanded by the differential circuit, the expansion speed is higher than that when the hydro valve 133 is switched to the normal expansion / contraction oil passage 136. Therefore, the time required for the boom expansion and contraction process becomes short.

Further, the controller 65, based on the signal from the cylinder length detecting means 90, receives the fixed pin driving means 40.
The fixing pin 16d gripped by the Fifth boom 1 is
When it is determined that the target fixing hole 54 of 5 has approached a predetermined distance, a telescopic cylinder deceleration signal is output to the drive hydraulic pressure supply means 100. Specifically, during the boom extension process, the cylinder length detecting means 9 described above is used.
0 is the controller 65 for the extension length signal of the telescopic cylinder 1.
When the controller 65 determines that the deceleration start point has been reached, the controller 65 starts decreasing the output signal value to the solenoid proportional valve 101. The pilot type switching valve 103 is gradually switched to the neutral side, and the opening area of the spool is reduced. The flow rate passing through the pilot type switching valve 103 is reduced regardless of the load on the telescopic cylinder 1 due to the action of the flow control valve 109, so that the extension speed of the telescopic cylinder 1 is reduced. When the deceleration end point is reached, the output from the controller 65 to the solenoid proportional valve 101 becomes constant at a predetermined low value. That is, the extension speed of the telescopic cylinder 1 is kept low. When the controller 65 determines that the fixing pin 16d has reached the target position of the fixing hole, the boom-to-boom fixing process described below is performed.

After the end of the boom extension / contraction stroke, the cylinder length detecting means 90 of the extension / contraction mechanism controller detects the extension / contraction length of the extension / contraction cylinder in the target boom extension / contraction stroke. The controller 65 reads out the specified expansion / contraction length determined by the stored position of the fixing hole of the boom-to-boom fixing means based on the detection value of the cylinder length detecting means,
The specified extension / contraction length is the extension / contraction length in the target boom extension / contraction process. Further, the controller 65 further determines the boom state after the extension / contraction operation from the boom state before the extension / contraction operation and the extension / contraction length in the boom extension / contraction stroke. (Boom-to-boom fixing stroke) The configurations of the boom / cylinder connecting means 20, the boom-to-boom fixing means 50, and the fixing pin driving means 40 are the same before and after the boom expanding / contracting stroke, and therefore will be described using FIG. 2 used previously. 55 is a fixed boss provided on the side surface of the tip portion of the fifth boom 15,
A fixing hole 54 is provided inside thereof. A signal is output from the controller 65 of FIG. 4 to the solenoid valve 108, and the fixed pin drive cylinder 41 of the fixed pin drive means 40 is output.
When is reduced, the tip portion 53 of the fixing pin 16d enters the fixing hole 54. The balls 35 of the ball lock mechanism 34 of the boom-to-boom fixing means 50 of the top boom base end portion 16a enter into the notches 36 of the fixing pin 16d, and the fixing pin 16d is held with its tip portion 53 inserted in the fixing hole 54. . As a result, the top boom base end portion 16a and the fifth boom 15 are fixed. (Cylinder / boom connection release process) Further, when the extension side operation of the extension / contraction operation lever 61 is continued, the controller 65 connects the cylinder / boom connection means 20 to the connection pin 2.
Output a 1-out signal. Specifically, a signal is sent to the solenoid switching valve 107 of FIG. 11, the connecting pin drive cylinder 21 is driven, and the connecting pin 23 is moved to the extraction side. That is, from the state shown in FIG.
When the connecting pin drive cylinder 21 of the boom connecting means 20 is extended, the connecting pin 23 is connected to the top boom base end portion 16a.
It is pulled out from the connection hole 16b. As a result, the connection between the cylinder tube rod side end 3 of the telescopic cylinder 1 and the top boom base end 16a is released. (Expansion / contraction cylinder expansion / contraction process) The connecting pin state detecting means 1
When the disconnection between the cylinder / boom connecting means 20 and the top boom base end portion 16a is confirmed by the signal from the controller 10, the controller 65 causes the driving hydraulic pressure supplying means 10 to be released.
A signal is sent to 0, and the telescopic cylinder 1 independently starts the telescopic operation without driving any boom. In this case, since the telescopic cylinder 1 performs the contracting operation, the hydro valve 133 that constitutes the differential switching valve does not switch to the differential oil passage 137 side, and normally remains in communication with the telescopic oil passage 136 side. .

Specifically, as the contents of the expansion / contraction cylinder expansion / contraction process, a signal is output from the controller 65 of FIG. 4 to the solenoid proportional valve 102, and pilot pressure is applied to the pilot type switching valve 103 to switch the expansion / contraction cylinder 1 to contract. To do.

Further, based on the signal from the cylinder length detecting means 90, the controller 65 causes the connecting pin 23 of the cylinder / boom connecting means 20 to move the base end portion 15a of the fifth boom.
When it is judged that the connecting hole 15b has been approached to a predetermined distance, the expansion / contraction cylinder deceleration signal is output to the drive hydraulic pressure supply means 100. Specifically, during the expansion / contraction cylinder contraction process, the cylinder length detection means 9 described above is used.
0 is the controller 65 for the expansion / contraction length signal of the expansion / contraction cylinder 1.
When the controller 65 determines that the deceleration start point has been reached, the controller 65 starts decreasing the output signal value to the solenoid proportional valve 102. The pilot type switching valve 103 is gradually switched to the neutral side, and the opening area of the spool is reduced. The flow rate passing through the pilot type switching valve 103 is reduced regardless of the load on the telescopic cylinder 1 due to the action of the flow control valve 109, so that the extension speed of the telescopic cylinder 1 is reduced. When the deceleration end point is reached, the output from the controller 65 to the solenoid proportional valve 102 becomes constant at a predetermined low value. That is, the contraction speed of the telescopic cylinder 1 is kept low.

The target position for shifting to the cylinder / boom coupling stroke is, together with the signal from the cylinder length detector 90,
It is determined by the signal from the boom base end position detecting means 80. Specifically, it is determined that the proximity switch 85 shown in FIG. 6 has reached the target position by detecting the detection piece 15f installed on the base end portion 15a of the fifth boom,
The process moves to the cylinder / boom coupling process described below. (Cylinder / boom connection process) A connection signal is output from the controller 65 to the cylinder / boom connection means 20. Specifically, when a signal is output from the controller 65 to the solenoid valve 107 of FIG. 4 and the connecting pin drive cylinder 21 shown in FIG. 2 is contracted, the connecting pin drive lever 22 swings and the connecting pin 23 moves. Enter into the connection hole 15b of the base end portion 15a of the fifth boom. As a result, the cylinder tube side end 3 of the telescopic cylinder 1 and the fifth boom base end 15a are integrally connected.

After that, when the fifth boom 15 is extended by repeating the above-described strokes to reach the desired final boom state shown in FIG. 8, the control device of the telescopic mechanism ends its operation. As compared with the conventional telescopic cylinder that does not use a differential circuit, the total time from the start of the telescopic operation to the final boom state is shorter.

According to the telescopic mechanism of the invention of the present application, regardless of whether or not the boom is driven, the speed at the time of extension of the telescopic cylinder is increased to shorten the time, so that the telescopic boom 10 as a whole is It goes without saying that the total time can be shortened not only in the case of extending the telescopic boom 10 but also in the contracting operation of contracting the entire telescopic boom 10.

[0039]

According to the invention described in claim 1 of the present application, when the expansion cylinder is extended by the differential extension oil passage, the time required for the extension is longer than that by the normal extension oil passage. Since the amount of oil required for the extension is small, the time is short. Therefore, it is possible to reduce the total time required to bring the entire telescopic boom into the desired telescopic state.

According to the second aspect of the present invention, since the telescopic mechanism control device switches the differential switching valve to the differential extension oil passage only when the telescopic boom has a predetermined undulation angle or more. The telescopic cylinder can be differentially extended only when the extension angle is equal to or more than a predetermined angle at which the extension operation can be automatically performed by the differential extension oil passage under the control of the extension mechanism controller.

According to the third aspect of the present invention, the expansion mechanism control device switches the differential switching valve to the differential extension oil passage only when the load of the expansion cylinder is less than or equal to a predetermined load. The expansion cylinder can be differentially expanded only when the load is equal to or less than a predetermined load at which the expansion operation can be automatically performed by the differential expansion oil passage under the control of the expansion mechanism controller.

[Brief description of drawings]

FIG. 1 is a cross-sectional view along a telescopic cylinder of a 6-stage telescopic boom in which a telescopic mechanism including one telescopic cylinder is used.

FIG. 2 is a sectional view taken along line AA of FIG.

3 is a BB arrow view of FIG. 2. FIG.

4A and 4B are a block diagram and a hydraulic circuit diagram of a control device for an expansion / contraction mechanism according to an embodiment of the present invention.

FIG. 5 is a display screen of expansion / contraction related information display means.

FIG. 6 is a specific example of a boom base end position detecting means.

FIG. 7 is a view taken along the line CC of FIG.

FIG. 8 is a view showing a state in which the top boom and the fifth boom are extended at the maximum hoisting angle of the telescopic boom.

[Explanation of reference numerals] 1 is a telescopic cylinder, 2 is a cylinder tube, 3 is a cylinder tube rod side end, 4 is a rod, 5 is a rod end, 10 is a telescopic boom, 11 is a base boom, 12 is a second boom, 13 Is a third boom, 14 is a force boom, 15 is a fifth boom, 16 is a top boom, 1
6a is the base end of the top boom, 16c is a connecting boss, 16b
Is a connecting hole, 16e is a fixed pin housing member, 16d is a fixed pin, 16f is a detection piece, 20 is a cylinder / boom connecting means, 21 is a connecting pin drive cylinder, 22 is a connecting pin drive lever, 23 is a connecting pin, and 25 is a connecting pin. Trunnion member, 33
Is a connecting member, 34 is a ball lock mechanism, 35 is a ball,
36 is a notch, 40 is a fixed pin drive means, 41 is a fixed pin drive cylinder, 42 is a fixed pin drive lever, 50 is a boom boom fixing means for the top boom, 51 and 54 are fixing holes for the fifth boom, and 52 and 55 are fifths. Boom fixing boss, 53 is a tip of a fixing pin, 60 is a telescopic operating means, 6
1 is a telescopic operation lever, 63 is a final boom state input means,
Reference numeral 65 is a controller, 70 is expansion / contraction related information display means, and 7
5 is an expansion / contraction state detecting means, 80 is a boom base end position detecting means, 82 to 86 are proximity switches, 90 is a cylinder length detecting means, 91 is a cord, 95 is a length detector, 100 is a drive hydraulic pressure supplying means, 101 And 102 are solenoid proportional valves, 103
Is a pilot type switching valve, 104 is a counter balance valve,
109 is a flow control valve, 107 and 108 are solenoid switching valves, 110 is a connecting pin state detecting means, 111 is a detecting piece,
Reference numerals 112 and 113 are proximity switches, 120 is fixed pin state detection means, 121 is a detection piece, 130 is an extension side oil passage, 13
1 is an extension side oil chamber, 132 is a first outlet port of a pilot type switching valve, 133 is a hydro valve, 134 is a reduction side oil chamber, 135 is a second outlet port of a pilot type switching valve,
136 is a normal expansion / contraction oil passage, 137 is a differential expansion oil passage, 138.
Is a solenoid valve, 140 is an overload prevention device, 141 is a telescopic boom hoisting angle detector, 142 is an telescopic boom length detector, and 143 is an telescopic boom moment detector.

Claims (3)

[Claims] 1. A telescopic boom in which an intermediate boom and a top boom are telescopically inserted in the base boom, and a rod end of the telescopic boom is supported by the base end of the telescopic boom. One telescopic cylinder and the rod end of the cylinder tube of the telescopic cylinder are selectively moved by retracting the built-in connecting pin toward the connecting hole at the base end of the desired boom. A cylinder / boom connecting means that can be connected / released to / from the boom base end, and a built-in fixing pin that is located at the inner boom base end of the adjacent boom and that moves toward the fixing hole provided in the proper position of the outer boom. By this means, boom-to-boom fixing means capable of fixing and releasing the adjacent booms to each other and the end portion of the telescopic cylinder on the side of the cylinder tube rod. An expansion / contraction mechanism configured by a fixed pin driving means that moves forward / backward by acting on an inner end of the fixed pin at a base end portion, the drive hydraulic pressure supply supplying a drive hydraulic pressure to a hydraulic actuator included in the expansion / contraction mechanism. Means, a telescopic mechanism operating means for inputting a final boom state of the telescopic boom and operating the telescopic mechanism until the final boom state is reached, a cylinder length of the telescopic cylinder, and a connecting pin of the cylinder / boom connecting means. An expansion / contraction state detecting means for detecting the connection state, the fixing state of the fixing pin of the boom-to-boom fixing means, and the boom base end position of the boom where the cylinder / boom connecting means is located; and the extension / contraction mechanism operating means. A controller that receives an operation signal and a detection signal from the expansion / contraction state detection means and outputs a drive signal to the drive hydraulic pressure supply means. In a telescopic mechanism that telescopically drives the intermediate boom and the top boom step by step under the control of the telescopic mechanism control device, the drive hydraulic pressure supply means includes an extension side oil chamber of the telescopic cylinder and a first outlet port of the telescopic operation switching valve. And a differential switching valve between the contraction-side oil chamber of the telescopic cylinder and the second outlet port of the telescopic operation switching valve. By switching between the contraction side oil chamber of the telescopic cylinder and the second side of the telescopic operation switching valve.
It is possible to switch between a normal expansion oil passage communicating with the outlet port of the expansion cylinder, and a differential expansion oil passage connecting the reduction side oil chamber of the expansion cylinder with the first outlet port of the expansion operation switching valve. Stretching mechanism. 2. The telescopic mechanism according to claim 1, wherein the telescopic mechanism control device includes a telescopic boom hoisting angle detector, and the controller receives the detection signal from the telescopic boom hoisting angle detector. The expansion / contraction mechanism is controlled so that the differential switching valve can be switched to the differential extension oil passage only when is greater than or equal to a predetermined undulation angle. 3. The telescopic mechanism according to claim 1, wherein the telescopic mechanism control device includes a telescopic cylinder load detector, and the controller determines that the telescopic cylinder is predetermined by a detection signal from the telescopic cylinder load detector. The expansion / contraction mechanism is controlled so that the differential switching valve can be switched to the differential extension oil passage only when the load is equal to or less than the load.