JP2019142623A - Expansion mechanism - Google Patents

Abstract

To provide an electromagnetic switching valve for pinning and holding when the B pin cylinder 3 and the C pin cylinder 2 are single acting.SOLUTION: A hydraulic pressure supply part 1 includes an air pressure source 20, a check valve 21 that passes air from the air pressure source 20 and blocks return, an air pressure supply electromagnetic switching valve 22 that can be switched to the three positions of shutting off air from the check valve 21, communicating with a first outlet port 24, and communicating with a second outlet port 25, a first pneumatic passage 26 through which air sent from the first outlet port 24 flows, a first pneumatic/hydraulic conversion part 32 that converts the pneumatic pressure from the first pneumatic passage 26 into hydraulic pressure and supplies hydraulic pressure to the first hydraulic cylinder 3, a second pneumatic passage 27 through which air sent from the second outlet port 25 flows, and a second pneumatic/hydraulic conversion part 33 that converts the pneumatic pressure from the second pneumatic path 27 into hydraulic pressure and supplies the hydraulic pressure to the second hydraulic cylinder 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an expansion / contraction mechanism (hereinafter referred to as “one-cylinder expansion / contraction mechanism”) that expands / contracts an expansion / contraction boom of a mobile crane using a single expansion / contraction cylinder, and in particular, the hydraulic / pneumatic circuit of the single-cylinder expansion / contraction mechanism. Regarding technology.

  The one-cylinder extension / contraction mechanism has one extension / contraction cylinder installed in the extension / contraction boom. One end of the telescopic cylinder is pivotally supported by the base end portion of the base boom. Further, the single cylinder expansion / contraction mechanism has a fixed pin (hereinafter referred to as “B pin”) and a hydraulic cylinder (hereinafter referred to as “B pin cylinder”) for moving the B pin forward and backward in the movable portion of the expansion cylinder. There is an inter-boom fixing means for fixing the two booms to be fixed by B pins. Further, the single cylinder expansion / contraction mechanism has a connecting pin (hereinafter referred to as “C pin”) and a C pin cylinder that expands / contracts the C pin in the expansion / contraction cylinder movable part, and includes a specific boom that expands and contracts and a telescopic cylinder movable part. Cylinder / boom coupling means coupled by a C pin.

The one-cylinder expansion / contraction mechanism has a hydraulic pressure supply unit composed of a hose reel or the like for supplying hydraulic pressure from the expansion cylinder fixed side to the B pin cylinder and the C pin cylinder arranged in the expansion cylinder movable unit. In the one-cylinder expansion / contraction mechanism having the above-described configuration, the specific boom and the expansion / contraction cylinder are connected by the hydraulic pressure supplied from the hydraulic pressure supply unit, and the fixed state between the specific boom and the adjacent outer boom is released. In this state, the boom is extended and retracted step by step by extending and retracting the telescopic cylinder.

  In the one-cylinder expansion / contraction mechanism, the B-pin cylinder and the C-pin cylinder are arranged in the expansion / contraction cylinder movable part, so that the hydraulic line from the hydraulic source on the expansion cylinder fixing side to the B-pin cylinder and the C-pin cylinder becomes very long. . Therefore, in order to ensure the smooth operation of the B pin and the C pin under low temperature operation, it is necessary to increase the inner diameter of the hydraulic pipe line, and the size of the hose reel increases.

Therefore, the applicant arranges an air over hydraulic booster (hereinafter referred to as “AOH booster”) in the movable part of the telescopic cylinder, and applies air pressure to the long pipe section from the fixed side of the telescopic cylinder to the movable part of the telescopic cylinder. A one-cylinder expansion / contraction mechanism (hereinafter referred to as “AOH type”) that is excellent in responsiveness at low temperatures by being used has been proposed (Patent Document 1).

  Furthermore, the applicant has a single cylinder expansion / contraction mechanism with excellent maintainability when the electromagnetic switching valve breaks down by arranging two AOH type air pipes and arranging all necessary electromagnetic switching valves on the expansion cylinder fixed side. (Hereinafter referred to as “twin hose type AOH type”) (Patent Document 2).

Japanese Patent Laid-Open No. 2006-141542 WO2017 / 150706A1 publication

  However, in the twin hose type AOH type described in Patent Document 2, when the B-pin cylinder and the C-pin cylinder are single-acting, a dedicated electromagnetic switching valve for holding when the pin is pulled out on the expansion cylinder fixed side (patent The second electromagnetic switching valve 38) shown in FIG.

  Therefore, in the present invention, paying attention to the characteristic that the air pressure can be released to the atmosphere and there is no need to prepare a return passage, a check valve is used instead of the B pin cylinder and the C pin cylinder pull-out holding instead of the electromagnetic switching valve. Therefore, we propose a one-cylinder expansion / contraction mechanism with a hydraulic supply unit that is inexpensive, has excellent equipment mounting properties, and has a low risk of failure.

The telescopic mechanism of the present invention includes a telescopic cylinder that is internally mounted in an telescopic boom in which a plurality of booms are telescopically fitted, and one end of which is pivotally supported by a base end portion of a base boom, a fixing pin, and the fixing A telescopic cylinder movable part having a first hydraulic cylinder for advancing and retracting the pin, and fixing means for inter-boom fixing that fixes two adjacent booms of the plurality of booms by the fixing pin, and the connecting pin and the connecting pin are advanced and retracted A cylinder / boom coupling means that has a second hydraulic cylinder to be expanded and contracted in the movable part of the telescopic cylinder, and that couples the specific boom to be expanded and contracted among the plurality of booms and the telescopic cylinder movable part by the coupling pin; And a hydraulic pressure supply unit that supplies hydraulic pressure to the cylinder and the second hydraulic cylinder, and the specific boom and the telescopic cylinder movable unit are connected to each other, and An expansion / contraction mechanism that expands / contracts the plurality of booms one step at a time by extending / contracting the expansion / contraction cylinder in a state where the fixed state of the specific boom and the adjacent outer boom is released, the first hydraulic cylinder, The second hydraulic cylinder is a single-acting hydraulic cylinder that is spring-biased on the return side, and the hydraulic pressure supply unit passes an air pressure source and a check valve that passes air from the air pressure source and blocks the return. And an air pressure supply electromagnetic switching valve that can be switched to three positions: shutting off air from the check valve, communicating with the first outlet port, and communicating with the second outlet port, and is sent from the first outlet port. A first pneumatic passage through which air flows, a first pneumatic-hydraulic converter that converts pneumatic pressure from the first pneumatic passage into hydraulic pressure and supplies hydraulic pressure to the first hydraulic cylinder, and the second outlet Second air pressure through which air sent from the port flows And a second air-hydraulic converter that converts air pressure from the second air pressure path to oil pressure and supplies the oil pressure to the second hydraulic cylinder, and the air pressure source, the check valve, The air pressure supply electromagnetic switching valve is disposed on the expansion cylinder fixed side, and the first automatic quick exhaust valve, the first air hydraulic pressure conversion unit, the second automatic quick exhaust valve, and the second air hydraulic pressure conversion unit. Is arranged in the movable part of the telescopic cylinder.

  The telescopic mechanism of the present invention includes a hydraulic pressure supply unit that is inexpensive, has excellent equipment mounting properties, and has a low risk of failure by using a check valve instead of an electromagnetic switching valve to hold the B pin cylinder and C pin cylinder. This cylinder expansion / contraction mechanism can be provided.

1 is a hydraulic / pneumatic circuit diagram showing a hydraulic pressure supply unit according to an embodiment of the present invention.

  A hydraulic pressure supply unit 1 according to an embodiment of the present invention will be described with reference to FIG. The hydraulic pressure supply unit 1 supplies hydraulic pressure to the C pin cylinder 2 and the B pin cylinder 3 of the single cylinder expansion / contraction mechanism. Since the telescopic boom and the telescopic cylinder to which the present invention is applied are the same as those described in Patent Document 2, detailed description thereof is omitted. As shown in FIG. 1, in the hydraulic pressure supply unit 1, hydraulic pressure is supplied to the B pin cylinder 3 of the boom fixing means 4 and the C pin cylinder 2 of the cylinder / boom coupling means 5.

  The C pin cylinder 2 arranged in the telescopic cylinder movable part 6 advances and retreats the C pin 7 incorporated toward the connection hole of the target boom (specific boom). The C pin cylinder 2 selectively connects / disconnects the telescopic cylinder movable part 6 and the specific boom. The C pin 7 is biased to the connecting side by a tension coil spring 8. The C pin cylinder 2 and the C pin 7 are related by a C pin drive lever 9. The C pin cylinder 2 is a single action hydraulic cylinder. The C pin cylinder 2 expands when hydraulic pressure is supplied via the hydraulic line 10. When the C pin cylinder 2 is extended, the C pin 7 is driven to the release side. When the hydraulic pressure supply to the hydraulic line 10 is cut off, the C pin cylinder 2 is contracted by the urging force of the tension coil spring 8, and the C pin 7 is driven to the connection side.

The B pin cylinder 3 disposed in the telescopic cylinder movable part 6 drives the B pin 11 of the specific boom forward and backward. The B pin 11 is biased to the fixed side by a compression coil spring 12. The B pin cylinder 3 has a built-in compression coil spring 13 and is biased toward the contraction side. The B pin cylinder 3 is a single acting hydraulic cylinder. The B pin cylinder 3 and the B pin 11 are associated by a B pin drive lever 14. The B pin cylinder 3 is supplied with hydraulic pressure via one hydraulic line 15 and extends. The extended B pin cylinder 3 drives the B pin 11 to the release side. When the hydraulic pressure supply to the hydraulic line 15 is interrupted, the B pin cylinder 3 is reduced by the urging force of the compression coil spring 13. At the same time, the B pin 11 is driven to the fixed side by the urging force of the compression coil spring 12.

  As shown in FIG. 1, the hydraulic pressure supply unit 1 includes an air pressure source 20, a check valve 21, and an air pressure supply electromagnetic switching valve 22 on the telescopic cylinder fixed side 23. Air from the air pressure source 20 is supplied to the air pressure supply electromagnetic switching valve 22 via the check valve 21. The air pressure supply electromagnetic switching valve 22 is a 5-port 3-position switching valve that blocks air from the air pressure source 20 (exhaust upstream air), communicates with the first outlet port 24, and communicates with the second outlet port 25. It is possible to switch to 3 positions of communication.

  The hydraulic pressure supply unit 1 also includes a first pneumatic path 26 and a second pneumatic path 27 that connect the telescopic cylinder fixed side 23 and the telescopic cylinder movable unit 6. Air from the first outlet port 24 of the air pressure supply electromagnetic switching valve 22 is sent to the first air pressure passage 26. Air from the second outlet port 25 of the air pressure supply electromagnetic switching valve 22 is sent to the second air pressure path 27. A first pneumatic hose reel 28 is used for the first pneumatic path 26, and a second pneumatic hose reel 29 is used for the second pneumatic path 27.

The hydraulic pressure supply unit 1 further includes a first automatic rapid exhaust valve 30, a second automatic rapid exhaust valve 31, a first air hydraulic pressure conversion unit 32, and a second air hydraulic pressure conversion unit 33 in the telescopic cylinder movable unit 6. Specifically, the first AOH booster 34 is used as the first air hydraulic pressure conversion unit 32, and the second AOH booster 35 is used as the second air hydraulic pressure conversion unit 33. As shown in FIG. 1, the air exiting the first outlet port 24 of the air pressure supply electromagnetic switching valve 22 passes through the first air pressure passage 26 (first air pressure hose reel 28) and the first automatic quick exhaust valve 30. Via the first air hydraulic pressure conversion unit 32 (first AOH booster 34). The hydraulic pressure output from the first air hydraulic pressure conversion unit 32 (first AOH booster 34) is supplied to the B pin cylinder 3 (first hydraulic cylinder) via the hydraulic line 15. Further, the air exiting the second outlet port 25 of the air pressure supply electromagnetic switching valve 22 passes through the second air pressure path 27 (second air pressure hose reel 29) and the second automatic quick exhaust valve 31 to the second air. It is supplied to the air hydraulic pressure conversion unit 33 (second AOH booster 35). Then, the hydraulic pressure output from the second pneumatic / hydraulic converter 33 (second AOH booster 35) is supplied to the C pin cylinder 2 (second hydraulic cylinder) via the hydraulic line 10.

  As shown in FIG. 1, the air pressure supply electromagnetic switching valve 22 and the controller 40 are connected by a signal line 41 and a signal line 42. The air pressure supply electromagnetic switching valve 22 is driven by a signal from the controller 40. The controller 40 outputs a predetermined drive signal corresponding to the expansion / contraction process of the single cylinder expansion / contraction mechanism.

  Table 1 shows the expansion / contraction state of the C pin cylinder 2 and the B pin cylinder 3 shown in FIG. 1, the energization state of the air pressure supply electromagnetic switching valve 22, the check valve 21, and the check valve 21. Indicates the state. As shown in Table 1, the one-cylinder expansion / contraction mechanism is stopped (STEP 0) from the boom fixing release step (STEP 1), the boom extension step (STEP 2), the boom fixing step (STEP 3), the cylinder / boom connection releasing step ( One boom is extended by going through the steps of STEP 4), telescopic cylinder reduction step (STEP 5), and cylinder / boom connection step (STEP 6). When extending a plurality of booms, the steps from STEP 1 to STEP 6 are further repeated. Note that the single cylinder telescopic mechanism can contract the telescopic boom by reversing the above steps.

  The operation of the hydraulic pressure supply unit 1 of the present invention will be described. As shown in Table 1, the C-pin cylinder 2 and the B-pin cylinder 3 are contracted in the stopping process (STEP 0) of the telescopic mechanism. That is, the telescopic cylinder movable portion 6 and the specific boom are connected by the cylinder / boom connecting means, and all adjacent booms are fixed by the boom fixing means. The air pressure supply electromagnetic switching valve 22 is not energized. Therefore, although air from the pneumatic pressure source 20 is supplied to the check valve 21, no air flows.

In the boom fixing release step (STEP 1), the B pin cylinder 3 is extended. Specifically, since the air pressure supply electromagnetic switching valve 22 is ON (communication) on the first outlet port side, the air from the air pressure source 20 passes through the check valve 21 and passes through the first outlet port 24 and the first outlet port 24. The air is supplied to the first AOH booster 34 through the pneumatic hose reel 28 and the first automatic quick exhaust valve 30. The hydraulic pressure generated by the first AOH booster 34 is supplied to the B pin cylinder 3 via the hydraulic line 15 and the B pin cylinder 3 extends. Then, the B pin 11 of the specific boom is driven to the release side against the urging force of the compression coil spring 12.

In the boom extension step (STEP 2), the specific boom is extended. Specifically, the first outlet port side ON (communication) of the air pressure supply electromagnetic switching valve 22 is continued. Therefore, the compressed air inside the first pneumatic hose reel 28, the first automatic quick exhaust valve 30, and the first AOH booster 34 after the check valve 21 is held by the check valve 21. Furthermore, the hydraulic pressure in the hydraulic line 15 and the B pin cylinder 3 after the first AOH booster 34 is also maintained. In this way, the B pin 11 can be held out by the check valve 21 without using an electromagnetic switching valve. That is, since air pressure is used, the air can be released to the atmosphere, and there is no need to prepare a return passage. Therefore, the check valve 21 that is a simple pneumatic device can be used. When the telescopic cylinder extends in the state described above, the specific boom connected to the telescopic cylinder movable portion 6 is extended.

In the boom-to-boom fixing step (STEP 3), the B pin cylinder 3 is reduced. Specifically, since the air pressure supply electromagnetic switching valve 22 is turned off at the first outlet port side and the second outlet port side is turned off, the compressed air inside the first pneumatic hose reel 28 after the first outlet port 24 is The air is supplied from the first exhaust port 50 of the air pressure supply electromagnetic switching valve 22. Then, the compressed air in the first AOH booster 34 is quickly exhausted from the first automatic rapid exhaust valve 30. Further, the hydraulic oil in the B pin cylinder 3 is pushed out by the urging force of the compression coil spring 13 and is absorbed by the first AOH booster 34 via the hydraulic line 15. As a result, the B pin cylinder 3 is reduced, so that the B pin 11 is moved to the fixed side by the urging force of the compression coil spring 12, and the specific boom is fixed to the adjacent boom.

In the cylinder / boom connection releasing step (STEP 4), the C pin cylinder 2 is extended. Specifically, since the air pressure supply electromagnetic switching valve 22 is turned ON (communication) on the second outlet port side, the air from the air pressure source 20 passes through the check valve 21 and passes through the second outlet port 25 and the second outlet port 25. The air is supplied to the second AOH booster 35 through the pneumatic hose reel 29 and the second automatic quick exhaust valve 31. The hydraulic pressure generated by the second AOH booster 35 is supplied to the C pin cylinder 2 via the hydraulic line 10 and the C pin cylinder 2 extends. Then, the C pin 7 is driven to the release side against the urging force of the tension coil spring 8.

In the telescopic cylinder reduction step (STEP 5), only the telescopic cylinder is contracted. Specifically, the second outlet port side ON (communication) of the air pressure supply electromagnetic switching valve 22 is continued. Therefore, the compressed air inside the second pneumatic hose reel 29, the second automatic quick exhaust valve 31, and the second AOH booster 35 after the check valve 21 is held by the check valve 21. Furthermore, the hydraulic pressure in the hydraulic line 10 and the C pin cylinder 2 after the second AOH booster 35 is also maintained. In this way, the C pin 7 can be pulled out and held by the check valve 21 without using an electromagnetic switching valve. That is, since air pressure is used, the air can be released to the atmosphere, and there is no need to prepare a return passage. Therefore, the check valve 21 that is a simple pneumatic device can be used. In the state described above, only the telescopic cylinder is contracted without expanding and contracting the boom.

In the cylinder / boom coupling step (STEP 6), the C-pin cylinder 2 is reduced. Specifically, since the pneumatic switching electromagnetic switching valve 22 is turned off at the first outlet port side and turned off at the second outlet port side, the compressed air inside the second pneumatic hose reel 29 after the second outlet port 25 is The air is exhausted from the second exhaust port 51 of the air pressure supply electromagnetic switching valve 22. Then, the compressed air in the second AOH booster 35 is rapidly exhausted from the second automatic rapid exhaust valve 31. Further, the hydraulic oil in the C pin cylinder 2 is pushed out by the urging force of the tension coil spring 8 and is absorbed by the second AOH booster 35 via the hydraulic line 10. As a result, the C-pin cylinder 2 is reduced, so that the C-pin 7 is moved to the connection side, and the telescopic cylinder movable portion 6 is connected to the next specific boom.

  As described above, the one-cylinder expansion / contraction mechanism of the present embodiment can use the check valve 21 instead of the electromagnetic switching valve, and can pull out and hold the B-pin cylinder 3 and the C-pin cylinder 2. . That is, the hydraulic pressure supply part of the single cylinder expansion / contraction mechanism can be made inexpensive, excellent in equipment mounting, and low in failure risk.

1: Hydraulic supply part 2: C pin cylinder (second hydraulic cylinder)
3: B pin cylinder (first hydraulic cylinder)
4: Boom-to-boom fixing means 5: Cylinder / boom connecting means 6: Telescopic cylinder movable part 7: C pin (connecting pin)
11: B pin (fixing pin)
20: Air pressure source 21: Check valve 22: Air pressure supply electromagnetic switching valve 23: Telescopic cylinder fixed side 24: First outlet port 25: Second outlet port 26: First air pressure path 27: Second air pressure Path 32: First pneumatic / hydraulic converter 33: Second pneumatic / hydraulic converter

Claims (1)

A telescopic cylinder that is internally mounted in a telescopic boom in which a plurality of booms are telescopically fitted, and one end of which is pivotally supported by the base end of the base boom;
An inter-boom fixing means having a fixed pin and a first hydraulic cylinder for moving the fixed pin forward and backward in a telescopic cylinder movable portion, and fixing two adjacent booms of the plurality of booms by the fixed pin;
A cylinder boom having a connecting pin and a second hydraulic cylinder for moving the connecting pin forward and backward in the telescopic cylinder movable part, and connecting the specific boom to be expanded and contracted among the plurality of booms and the telescopic cylinder movable part by the connecting pin. Connecting means;
A hydraulic pressure supply unit that supplies hydraulic pressure to the first hydraulic cylinder and the second hydraulic cylinder;
By extending and retracting the telescopic cylinder in a state where the specific boom and the telescopic cylinder movable part are connected and the fixed state of the outer boom adjacent to the specific boom is released, the plurality of booms are moved to one stage. An expansion mechanism that expands and contracts one by one,
The first hydraulic cylinder and the second hydraulic cylinder are single-acting hydraulic cylinders that are spring-biased on the return side,
The hydraulic pressure supply unit
An air pressure source,
A check valve that passes air from the air pressure source and blocks return;
An air pressure supply electromagnetic switching valve capable of switching to the three positions of shutting off air from the check valve, communicating with the first outlet port, and communicating with the second outlet port;
A first pneumatic passage through which air sent from the first outlet port flows;
A first air-hydraulic converter that converts air pressure from the first air pressure path to oil pressure and supplies oil pressure to the first hydraulic cylinder;
A second pneumatic path through which air sent from the second outlet port flows;
A second air-hydraulic converter that converts air pressure from the second air pressure path to oil pressure and supplies oil pressure to the second hydraulic cylinder;
Have
The air pressure source, the check valve and the air pressure supply electromagnetic switching valve are arranged on the telescopic cylinder fixed side,
The telescopic mechanism, wherein the first automatic rapid exhaust valve, the first pneumatic hydraulic pressure conversion unit, the second automatic rapid exhaust valve, and the second pneumatic hydraulic pressure conversion unit are disposed in the telescopic cylinder movable unit.

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