JPH11193197A - Crane jib overhang, containment device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Left lock that reduces shock at the time of single top jumping and that occurs when the single top and the support stand interfere with each other when the jib is extended, or when the top boom and the connection bracket are locked. An object of the present invention is to provide a crane jib overhanging / retracting device that reliably prevents a pin from coming off. SOLUTION: A single top link 5 in which one is rotatably mounted on a top end of a boom 2 and a single top 5 is mounted on the other, and in conjunction with a lock operation of left lock pins 63, 67 by a left lock cylinder 61. Top link driving means 1 for rotating single top link 13 upward
5, the flow rate reducing means 40 for reducing the flow rate flowing into the left lock cylinder 61, and the changeover switch 37) are switched to either overhang or retracted, and the mode changeover switch 36 is inserted with the left lock pins 63, 67. And a controller 38 that outputs a flow rate reduction command to the flow rate reduction means 40 when the mode is switched to a jib extension / retraction device for a crane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane jib overhang and storage device.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS. As shown in FIG. 6, the crane top boom 3
A supplementary hook 6 is wound around the tip sheave 4 rotatably attached to the tip of the top boom, and a main sheave 7 attached rotatably to the tip of the top boom 3 has a main hook similar to the supplementary hook 6. A hook (not shown but having a larger allowable load than the auxiliary hook 6) is wound. The main hook 10 is used for low-speed, high-load work because the main hook 10 has a large hanging load because of a four-wire wire rope, but has a low line speed. The auxiliary hook 6 is used for high-speed, low-load work because of a single-hook wire. .
However, when the auxiliary hook 6 is used for jib work, the tip sheave 4 interferes when the jib 21 is extended and retracted.
The single top 4 that rotatably supports the tip sheave 4 together with the tip sheave 4 needs to be retracted to a place where there is no hindrance as shown in FIG.

In FIG. 6, a single top 5 is detachably attached to a bracket 9 attached to a lower portion of a front end of a top boom 3 by a fixing pin 11. The tip sheave 4 is axially mounted on the single top 5 by a tip sheave shaft 12. One end of a single top link 13 is mounted on the tip sheave shaft 12, and the other end of the single top link 13 is rotatably mounted on a guide sheave shaft 14 of a guide sheave 8 provided above the top boom 3. ing. A top link drive device 15 that rotates the single top link 13 is provided at the tip of the top boom 3. Further, the single top 5 is lifted forward and upward to the position shown in FIG.

In FIGS. 8 to 10, first to fourth brackets 31 to 34 are fixed in the left and right and up and down directions at the tip of the top boom 3, respectively.
1 is provided with pin holes 31a and 31b. The second bracket 32 to the fourth bracket 34 are provided with pin holes 32a to 34a, respectively. Rotating bracket 20
Pin holes 41 respectively engaging with the pin holes 31a to 34a at the distal end of the top boom 3 in the horizontal direction and the vertical direction of the base end.
c-44c each forked bracket 41a, 41b-
44a and 44b are provided. In the rotating bracket 20, an upper lock pin 63 and a lower lock pin 67 are installed on the axis of the pin holes 31a, 41c, 32a, and 42c, and the upper lock pin 63 is also provided on the axis of the pin holes 31b and 55c. A left lock cylinder 61 on which an integrated third connecting pin 64 is installed is provided. Similarly, the pin holes 33a,
The upper lock pin 73 is located on the axis of 43c, 34a, 44c.
And a lower lock pin 77 (see FIG. 12), and a right lock cylinder 71 is provided.

In FIG. 8, one end of a first link 52 is rotatably mounted on a first connecting pin 51 fixed to the upper surface of a rotating bracket 20, and a second link 54 is provided on the other end by a second connecting pin 53. Is rotatably connected at one end. At the other end of the second link 54, forked brackets 55a and 55b having a pin hole 55c are provided, and are detachably and rotatably connected by the pin hole 31b and the third connection pin 64. A rotary cylinder 56 rotatably mounted on the upper surface of the rotary bracket 20 by a fourth connecting pin 57
And the central portion of the first link 52 are rotatably connected by a fifth connecting pin 58. When the rotating bracket 20 is rotated by 180 ° in front of the top boom 3 to the position shown in FIG. 10, FIG. 11 (showing a state in which the wire rope in which the tilt cylinder 23 is contracted and the jib 21 is turned down is prepared for replacement). As shown, the support 20a of the rotating bracket 20
Comes to the lower surface 5a of the single top 5, the support 20a
Abuts against and supports the lower surface 5a of the single top 5.

A hydraulic circuit diagram at the time of overhang according to the prior art will be described with reference to FIG. (1). When the left lock pin is extended, when the solenoids SOL1a and SOL2 are excited, the pressure oil discharged from the hydraulic pump 25 is at the position a of the direction switching valve 26,
The air is supplied from the counter balance valve 65 to the extension chamber A of the left lock cylinder 61 via the extended position of the solenoid valve 81 and the a position of the solenoid valve 82. Left lock cylinder 6
The return oil of the first contraction chamber B is drained from the position a of the direction switching valve 26 to the tank 48 via the counter balance valve 65, the position b of the solenoid valve 86, and the extended position of the solenoid valve 81. (2). When SOL1a and SOL3 are excited, the hydraulic oil discharged from the hydraulic pump 25 receives the counterbalance valve via the position a of the direction switching valve 26, the position of the solenoid valve 83, and the position a of the solenoid valve 83. From 45, it is supplied to the extension chamber A of the rotary cylinder 65. The return oil from the contraction chamber B of the rotary cylinder 65 is drained from the position a of the direction switching valve 26 to the tank 48 via the counter balance valve 45, the position b of the solenoid valve 84, and the extended position of the solenoid valve 81. (3). When the right lock pin is extended When SOL1a and SOL5 are excited, the pressure oil discharged from the hydraulic pump 25 is counterbalanced via the a position of the direction switching valve 26, the extended position of the solenoid valve 81, and the a position of the solenoid valve 85. Right lock cylinder 71 from valve 75
Is supplied to the extension chamber A. The return oil from the contraction chamber B of the right lock cylinder 71 is drained from the position a of the direction switching valve 26 to the tank 48 via the counter balance valve 75, the position b of the solenoid valve 87, and the extended position of the solenoid valve 81. .

The operation of the prior art will be described. (1). As shown in FIG. 8, when the rotating bracket 20 on which the jib 21 is mounted is swung until it is stopped by the stopper 31c, as shown in FIG.
1 and a first forked bracket 4
The pin holes 41c provided in the first bracket 1a and 41b coincide with each other.
And the pin holes 42c provided in the second forked brackets 42a and 42b coincide with each other. (2). After the fixed lock pin 11 shown in FIG. 6 is pulled out and the bracket 9 and the single top 5 are separated, when SOL1a and SOL2 are excited as in the case of extending the left lock pin shown in FIG. The top boom 3 and the connection bracket 20 are locked by the lock pins 63 and 67.
Are linked.

(3) At the same time, as shown in FIG. 6, the plate 62 fixed to the upper lock pin 63 of the lock cylinder 61 rises, and as shown in FIG. The single top link 13 is lifted upward around the guide sheave shaft 14. (4). When the SOL2 is demagnetized as in the case of the overhang rotation shown in FIG.
6, the connecting bracket 20 is moved up and down by the left lock pin 6
It rotates around 3,67. As shown in FIG. 10, the connecting bracket 20 is projected forward to a position where the connecting bracket 20 is stopped by the stopper 33b, and a pin hole 33a provided in the first bracket 33 and a third forked bracket 43a,
43b (similar to FIG. 9 and omitted from the drawing), the pin holes 43c installed in the fourth bracket 34 and the pin holes 34a installed in the fourth bracket 34 at the lower part coincide with the pin holes 43a.
The pin hole 44c (not shown because it is the same as FIG. 9) installed at 44b matches. (5). When the right lock pin is extended as shown in FIG.
When L3 is demagnetized and SOL5 is excited instead, the top boom 3 and the connection bracket 20 are connected by the upper and lower right lock pins 73 and 77 of the right lock cylinder 71.

[0009]

Problems to be Solved by the Invention (1). The top link drive device 15 shown in FIG.
Since the lever ratio (L2 / L1) ≒ 20 for 3,
Even if the left lock cylinder 61 is operated normally, since the single top 5 moves at a speed about 20 times that of the cylinder, there is a problem that the shock increases at the time of starting and stopping. (2). In the jib overhang process, the upper and lower left lock pins 63,
67 are inserted into the pin holes 31a and 41a and the pin holes 32a and 42a, respectively.
With SOL2 demagnetized, the rotary cylinder 5
At 6, the jib 21 is rotated to the overhang position. The lock pin extension circuit of the left lock cylinder 61 has a counter balance valve 65 so that the left lock cylinder 61 does not contract. However, if the left lock cylinder 61 contracts even a little due to leakage of the spool of each valve, etc. The top link drive device 15 has a lever ratio (L2 / L1) ≒ 20 with respect to the two rotating shafts 14 and 153.
0 times lower. At this time, when the jib 21 is extended forward by the rotary cylinder 56, the support table 2 above the rotary bracket 20.
0a and the single top 5 interfered. (3). When the right lock pin extends, the SOL 2 remains demagnetized, so the upper lock pin 7 of the right lock cylinder 71
While the top boom 3 and the rotating bracket 20 are locked by the 3 and the lower lock pin 77 in the same manner as in FIG. 63 and 67 are pin holes 31
a, 41a and 32a, 42a.

The present invention has been made in view of the above-mentioned conventional problems, and it is intended to reduce the shock at the time of jumping up the single top 5 and to prevent interference between the single top 5 and the support base 20a when the jib 21 is extended. Alternatively, the left lock pin 61, which is generated when the top boom 3 and the connection bracket 20 are locked,
It is an object of the present invention to provide a crane jib overhanging / retracting device that reliably prevents the 67 from coming off.

[0011]

In order to achieve the above object, a first aspect of the present invention relates to a crane jib overhanging / retracting device according to the present invention, which is attached to and detached from a storage position juxtaposed on a side surface of a crane boom. A jib freely stored, a rotating bracket to which the jib is attached, a left lock pin for rotatably attaching the end of the boom and the rotating bracket in a substantially horizontal plane, a left lock cylinder for attaching and detaching the left lock pin, A rotating cylinder that is mounted between the end of the boom and the rotating bracket, rotates the rotating bracket around the left lock pin to the extended position of the front jib and the retracted position of the rear jib, and detachable to the lower part of the boom tip A single top freely mounted, a tip sheave rotatably mounted on the single top, a hydraulic pump that supplies hydraulic oil to the left lock cylinder and the rotating cylinder, and a jib tension In a jib extension / storage device of a crane having a changeover switch for switching storage and a mode changeover switch having at least a mode for inserting a left lock pin, one is rotatably mounted on the upper end of the boom and the other is single. A single top link with a top mounted thereon, a top link driving means for rotating the single top link upward in conjunction with a locking operation of a left lock pin by a left lock cylinder, and a flow reducing means for reducing a flow rate flowing into the left lock cylinder. And a controller that outputs a flow rate reduction command to the flow rate reduction means when the mode changeover switch is switched to either the overhang / retraction mode and the mode changeover switch is switched to the insertion position of the left lock pin. Features.

According to the first aspect of the invention, when the left lock cylinder is extended and the tip of the boom and the rotating bracket are rotatably locked by the left lock pin, the single top link is formed by the top link driving means. Rotate upward around the fulcrum at the top of the boom tip. At this time, when the controller inputs a signal indicating that the changeover switch has been switched to either the overstretched or retracted state and the mode changeover switch has been switched to the insertion of the left lock pin, the flow rate reduction means is issued by the flow rate reduction command from the controller. Reduces the flow rate flowing into the left lock cylinder, the extension speed of the left lock cylinder decreases.

For this reason, even if the lever ratio of the top link drive device is increased, the shock of starting and stopping when the left lock cylinder extends is reliably reduced, and operability and durability can be improved. .

According to a second aspect of the present invention, there is provided a crane jib overhanging / retracting device according to the first aspect, wherein the flow rate reducing means is a discharge volume control device for a hydraulic pump, and a flow rate control for controlling a flow rate flowing into a left lock cylinder. A pressure control valve for limiting the pilot pressure of a pilot-operated directional control valve interposed between the hydraulic pump and the left lock cylinder.

According to the second aspect of the present invention, the flow rate reducing means is a commonly used device, and is versatile so that the cost is reduced and the maintenance is easy.

According to a third aspect of the present invention, there is provided a crane jib overhanging / retracting device, comprising: a jib removably stored in a storage position juxtaposed on a side surface of a boom of a movable crane; and a rotating bracket to which the jib is attached. A left lock pin for rotatably attaching the end of the boom and the rotating bracket substantially in a horizontal plane,
Mounted between the left lock cylinder for attaching and detaching the left lock pin, the end of the boom and the rotating bracket, and rotating the rotating bracket around the left lock pin to the extended position of the front jib and the retracted position of the rear jib. A rotary cylinder to be supplied, a hydraulic pump for supplying pressure oil to the left lock cylinder and the rotary cylinder, and a changeover switch for switching between extension and storage of the jib;
In a jib extension / retraction device of a crane having a mode changeover switch for switching to a mode for inserting a left lock pin, when pressure oil is supplied to a rotary cylinder from a hydraulic pump, pressure oil is also supplied to the left lock cylinder. It is characterized by that.

According to the third aspect, when the hydraulic oil is supplied from the hydraulic pump to the rotary cylinder, the hydraulic oil is always supplied to the left lock cylinder. For this reason, when the jib is extended and retracted, the left lock pin is reliably prevented from coming off from the end of the boom and the rotating bracket, and safety is improved.

According to a fourth aspect of the present invention, there is provided a crane jib overhanging / retracting device according to the third aspect, wherein the single top is detachably attached to a lower end of the boom, and the single top is rotatably mounted on the single top. A single top link with one end rotatably mounted on the top end of the boom and a sheave end, and a single top link with a single top mounted on the other and a single top link rotated upward in conjunction with the lock operation of the left lock pin by the left lock cylinder And a top link driving means for causing

According to the fourth aspect, when the left lock cylinder is extended and the tip of the boom and the rotary bracket are rotatably locked by the left lock pin, the top sheave is driven by the top link driving means. A single top link with a single top rotatably mounted on one side is rotated upward about a fulcrum at the top end of the boom. Therefore, the locking of the left lock pin and the rotation of the single top link are performed on the left lock cylinder, thereby simplifying the device and reducing the cost.

According to a fifth aspect of the present invention, there is provided a crane jib overhanging / retracting device, comprising: a jib removably stored at a storage position juxtaposed to a side surface of a boom of a mobile crane; and a rotating bracket to which the jib is attached. A left lock pin for rotatably attaching the end of the boom and the rotating bracket substantially in a horizontal plane,
Mounted between the left lock cylinder for attaching and detaching the left lock pin, the end of the boom and the rotating bracket, and rotating the rotating bracket around the left lock pin to the extended position of the front jib and the retracted position of the rear jib. The rotation cylinder to be inserted, the right lock pin for inserting the boom tip and the rotation bracket at the extension position of the front jib, the right lock cylinder for attaching and detaching the right lock pin, and the left and right lock cylinders and the rotation cylinder. In a crane jib overhanging / retracting device having a hydraulic pump for supplying oil, a changeover switch for switching between extension and storage of the jib, and a mode changeover mode for inserting a left lock pin, a right lock is provided from the hydraulic pump. When the pressure oil is supplied to the cylinder, the pressure oil is also supplied to the left lock cylinder.

According to the fifth aspect, when the hydraulic oil is supplied from the hydraulic pump to the right lock cylinder, the hydraulic oil is always supplied to the left lock cylinder. For this reason, when the right lock cylinder is extended, the left lock pin is reliably prevented from coming off from the tip of the boom and the rotating bracket, thereby improving safety.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. In the following description, the same reference numerals are used for the same components as those used in the description of the related art.

In FIG. 1, at the front end of the top boom 3 of the most advanced boom 2 of the mobile crane 1, a single top 5 mounted on a single top link 13 similar to the prior art described with reference to FIG. Tip sheave 4 supported
The auxiliary hook 6 is hung on a wire rope 16 wound on a guide sheave 8 pivotally supported on the top end of the top boom 3.

The details of the link driving device 15 will be described with reference to FIG. A first lever 152 is provided at the tip of the top boom 3.
A roller 154 is attached to a tip end of the first lever 152. One end of a second lever 155 is fixed to the tip of the lever shaft 153 by serration or a key. The other end of the second lever 155 is a forked lever 13 fixed to the base end of a single top link 13 rotatably mounted on a guide sheave shaft 14 provided on the top boom 3.
a and the lock pin 159a, 1 via the connecting rod 158.
59b. When the lock cylinder 60 is shortened, the roller 154 of the first lever 152 is close to the upper surface of the link 62 fixed to the lock cylinder 61. When the lock cylinder 61 is extended, the upper surface of the link 62 contacts the roller 154. Contact and push up, 1st lever 1
By rotating 52 the single top link 13
Is rotated to lift the single top 5 and the tip sheave 4 upward.

A hydraulic circuit diagram at the time of overhang according to the prior art will be described with reference to FIG. (1). When the left lock pin is extended When SOL1a and SOL2 are excited, similar to the prior art,
Upper and lower left lock pins 63, 67 on the left lock cylinder 61
To connect the top boom 3 and the connection bracket 20. (2). When SOL1a and SOL3 are excited during overhang rotation, as in the prior art,
The connection bracket 20 is extended forward around the upper and lower left lock pins 63 and 67 by the rotary cylinder 65, and the upper and lower left lock pins 63 and
By 67, the top boom 3 and the connection bracket 20 are continuously connected. (3). When the right lock pin is extended When SOL1a and SOL5 are excited, as in the prior art,
Upper and lower left lock pins 73, 77 of right lock cylinder 71
The top boom 3 and the connection bracket 20 are connected with the upper boom 3 and the lower left lock pins 63 and 67, respectively.
Is continuously linked.

Referring to FIG. 4, a conventional hydraulic circuit diagram at the time of storage will be described. (1). When the right lock pin is contracted When SOL1b and SOL4 are excited, the pressure oil discharged from the hydraulic pump 25 passes from the counter balance valve 75 to the right lock cylinder 71 via the position a of the direction switching valve 26 and the storage position of the solenoid valve 81. It is supplied to the contraction chamber B. The return oil of the extension chamber A of the right lock cylinder 71 is drained from the position a of the direction switching valve 26 to the tank 48 via the counter balance valve 75, the position b of the solenoid valve 85, and the storage position of the solenoid valve 81, The upper and lower right lock pins 73 and 77 of the right lock cylinder 71 are pulled out of the top boom 3 and the connection bracket 20.

(2). At the time of storage rotation When SOL1b and SOL4 are excited, the pressure oil discharged from the hydraulic pump 25 is moved from the counter balance valve 75 to the contraction chamber of the right lock cylinder 71 through the position a of the direction switching valve 26 and the storage position of the solenoid valve 81. B. At the same time, the air is supplied from the counter balance valve 45 to the contraction chamber B of the rotary cylinder 56 via the position a of the solenoid valve 84. The return oil of the extension chamber A of the rotary cylinder 56 is drained from the position a of the direction switching valve 26 to the tank 48 via the counter balance valve 45, the position b of the solenoid valve 83, and the storage position of the solenoid valve 81, and is rotated. The rotation bracket 20 is rotated to the storage position by the cylinder 56.

(3). When the left lock pin is contracted When SOL1b and SOL2 are excited, the pressure oil discharged from the hydraulic pump 25 passes from the counter balance valve 75 to the right lock cylinder 71 via the position a of the direction switching valve 26 and the storage position of the solenoid valve 81. It is supplied to the contraction chamber B. At the same time, the air is supplied from the counter balance valve 65 to the contraction chamber B of the left lock cylinder 61 via the position a of the solenoid valve 82. The return oil of the extension chamber A of the left lock cylinder 61 is
The counter balance valve 65 is drained from the position a of the directional control valve 26 to the tank 48 via the storage position of the solenoid valve 81, and the upper and lower left lock pins 63 and 67 of the left lock cylinder 61 are connected to the top boom 3. Bracket 20
Extract from

In FIG. 5, the changeover switch 36 is extended,
When the mode switch 37 is switched to the left lock pin lock, the overhang or storage signal and the left lock pin lock signal are transmitted to the controller 38.
To enter. Then, the controller 38 outputs a control signal for reducing the discharge volume to a predetermined value to the solenoid 39a of the discharge volume control valve 39 constituting the discharge volume control device 40 of the hydraulic pump 25 shown in FIG. 3 or 4. Instead of controlling the discharge volume of the hydraulic pump 25, a control signal is output from the controller 38 to the flow control valve 47 or the pilot pressure control valve 46 as shown by a two-dot chain line in FIG. The amount of pressurized oil may be reduced.

The operation of the above configuration will be described. (1). When the changeover switch 36 is extended or stored,
When the mode changeover switch 37 is switched to the left lock pin lock, a control signal for reducing the discharge volume to a predetermined value is output from the controller 38 to the solenoid 39a of the discharge volume control valve 39 shown in FIG.
The discharge volume of No. 5 is reduced to a predetermined value. For this reason, the extension speed of the left lock cylinder 61 is reduced, and the shock when starting and stopping the left lock cylinder 61 is reliably reduced.

(2). When the connecting bracket 20 is extended forward by the rotary cylinder 56 by exciting the SOL 3 in the same manner as in the prior art during the overhang rotation shown in FIG. 3, the pressure oil is always supplied to the extension chamber A of the left lock cylinder 61. Therefore, the top boom 3 and the connection bracket 20 are connected by the upper and lower left lock pins 63 and 67. Therefore, the left lock pins 63 and 67 are reliably prevented from coming out of the top boom 3 and the connection bracket 20 while the connection bracket 20 is being extended forward by the rotary cylinder 56.

(3). At the time of the overhang rotation shown in FIG. 3, SOL5 is excited as in the prior art, and the right lock cylinder 71 is used to excite the upper and lower right lock pins 73,
When the top boom 3 and the connection bracket 20 are connected by 77, the pressurized oil is always supplied to the extension chamber A of the left lock cylinder 61. Therefore, the top boom 3 and the connection bracket 20 are connected by the left lock pins 63 and 67. Is done. For this reason, the right lock pin 7 of the right lock cylinder 71
While the top boom 3 and the connection bracket 20 are being connected by the third and third 77, the left lock pins 63 and 67 are reliably prevented from coming off from the top boom 3 and the connection bracket 20.

[Brief description of the drawings]

FIG. 1 is a side view of a mobile crane equipped with a jib overhanging / retracting device according to the present invention.

FIG. 2 is a perspective view showing details of a top link driving device of the jib overhanging / retracting device according to the present invention.

FIG. 3 is a hydraulic circuit diagram of the jib projecting / retracting device according to the present invention at the time of projecting.

FIG. 4 is a hydraulic circuit diagram of the jib overhanging / storing device according to the present invention at the time of storage.

FIG. 5 is a diagram showing a pump discharge volume control system of the jib overhanging / retracting device according to the present invention.

FIG. 6 is a side view showing details of a conventional boom tip portion.

FIG. 7 is a side view showing a state where a tip sheave of FIG. 6 is flipped up.

FIG. 8 is a plan view showing the jib projecting state of FIG. 6;

9 is a partial cross-sectional side view showing a shortened state of the lock pin driving device of FIG. 8;

FIG. 10 is a plan view showing an extended state of the jib in FIG. 8;

FIG. 11 is a diagram showing a state in which the wire rope is ready for replacement in a state where the jib is extended.

FIG. 12 is a hydraulic circuit diagram of the related art at the time of overhang.

[Explanation of symbols]

1: Mobile crane, 2: Boom, 3: Top boom,
4 ... tip sheave, 5 ... single top, 6 ... auxiliary hook, 7 ... main sheave, 8 ... guide sheave, 9 ... bracket, 11 ... fixed lock pin, 12 ... tip sheave shaft, 13
... single top link, 13a ... bifurcated lever, 14 ...
Guide sheave shaft, 15 ... Link drive device, 152 ... First
Lever, 153: lever shaft, 154: roller, 155 ...
Second lever, 158 ... Connecting rod, 159a, 159b
... lock pin, 16 ... wire rope, 20 ... rotating bracket, 20a ... support base, 21 ... jib, 23 ... tilt cylinder, 25 ... hydraulic pump, 26 ... directional control valve, 27 ... pilot valve, 29 ... control pump, 39 ... Discharge volume control valve, 39a ... solenoid, 30 ... rotary device, 31 ... first
Brackets, 31a, 31b, 32a to 34a, 41c
~ 44c, 55c ... pin hole, 32 ... second bracket, 3
Reference numeral 3: third bracket, 34: fourth bracket, 40: discharge volume control device, 41a, 41b: first forked bracket, 42a, 42b: second forked bracket, 43a, 4
3b: third forked bracket, 44a, 44b: fourth forked bracket, 45, 65, 75: counter balance valve,
46 ... Pilot pressure control valve, 47 ... Flow control valve, 51 ...
1st connection lock pin, 52 ... 1st link, 53 ... 2nd connection lock pin, 54 ... 2nd link, 55a, 55b ... bifurcated bracket, 56 ... rotary cylinder, 57 ... 4th connection lock pin, 58 ... 5th Connection lock pin, 60: left lock pin drive, 61: left lock cylinder, 62: plate, 63: upper left lock pin, 67: lower left lock pin, 6
4. Third connecting lock pin, 70 right lock pin driving device, 71 right lock cylinder, 73 upper right lock pin,
77 ... lower right lock pin.

Claims (5)

[Claims] A jib (21) removably stored in a storage position juxtaposed on the side of a crane boom (2), and a jib (2).
1) a rotating bracket (20), a left lock pin (63, 67), and a left lock pin for rotatably mounting the end of the boom (2) and the rotating bracket (20) in a substantially horizontal plane. (63,67)
Is mounted between the left lock cylinder (61) for attaching and detaching and the tip of the boom (2) and the rotating bracket (20).
A rotating cylinder (20) for rotating the (20) around the left lock pin (63, 67) to the extended position of the front jib (21) and the retracted position of the rear jib (21), and the boom (2) Single top (5) and single top (5) detachably attached to the lower part of the tip
The sheave (4), which is rotatably mounted on the cylinder, the hydraulic pump (25) that supplies hydraulic oil to the left lock cylinder (61) and the rotary cylinder (56), and the extension and storage of the jib (21). In a crane jib extension / retraction device having a mode changeover switch (37) having at least a mode changeover switch (36) and a mode for inserting a left lock pin (63, 67), an upper end of a boom (2) is provided. Single top link with one rotatably mounted on the other and a single top (5) on the other
(5) and the left lock pin (63,
Single top link (13) in conjunction with the lock operation of 67)
The top link drive means (15) for rotating the upper part upward, the flow rate reducing means (40) for reducing the flow rate flowing into the left lock cylinder (61), and the changeover switch (36) A controller (38) for outputting a flow rate reduction command to the flow rate reduction means (40) when the mode switch (37) is switched to the insertion position of the left lock pin (63, 67). A crane jib overhang and storage device. 2. The control device according to claim 1, wherein the flow rate reducing means is a discharge volume control device for the hydraulic pump, a flow control device for controlling a flow rate flowing into the left lock cylinder (61), or a hydraulic pump and the left lock cylinder (61). A jib overhanging / retracting device for a crane, which is any one of pressure control valves for limiting a pilot pressure of a pilot-operated directional switching valve interposed therebetween. 3. A jib (21) removably stored in a storage position juxtaposed on a side of a crane boom (2), and a jib (2).
1) a rotating bracket (20), a left lock pin (63, 67), and a left lock pin for rotatably mounting the end of the boom (2) and the rotating bracket (20) in a substantially horizontal plane. (63,67)
Is mounted between the left lock cylinder (61) for attaching and detaching and the tip of the boom (2) and the rotating bracket (20).
A rotary cylinder (56) for rotating the (20) around the left lock pin (63, 67) to the extended position of the front jib (21) and the retracted position of the rear jib (21), and the left lock cylinder ( 61) and a hydraulic pump (25) for supplying pressurized oil to the rotating cylinder (20), and a jib (21)
In a crane jib overhanging / retracting device having a changeover switch (36) for switching overhang / retraction of the crane and a mode changeover switch (37) for switching to a mode for inserting the left lock pin (63, 67), a hydraulic pump ( A jib overhanging / retracting device for a crane, wherein when the pressurized oil is supplied from 25) to the rotary cylinder (56), the pressurized oil is also supplied to the left lock cylinder (61). 4. A single top (5) detachably attached to a lower end of a tip of a boom (2), and a tip sheave (4) rotatably mounted on the single top (5).
And one of them is rotatably attached to the top of the boom (2),
On the other hand, a single top link (13) equipped with a single top (5) and a left lock pin by a left lock cylinder (61)
Single top link in conjunction with lock operation of (63,67)
A crane jib overhanging / retracting device comprising top link drive means (15) for rotating (13) upward. 5. A jib (21) removably stored in a storage position juxtaposed on the side of a crane boom (2), and a jib (2)
Rotating bracket (20) with attached 1), left lock pin (3), and left lock pin (3) for rotatably mounting the end of boom (2) and rotating bracket (20) in a substantially horizontal plane. ) Is mounted between the left lock cylinder (3) and the end of the boom (3) and the rotation bracket (30), and the rotation bracket (30) is rotated around the left lock pin (63, 67). The rotating cylinder (56) that rotates between the extended position of the jib (21) and the retracted position of the rear jib (21), and the tip of the boom (2) and the rotating bracket ( 56) and the right lock pin (73,
77), a right lock cylinder (71) for attaching and detaching the right lock pins (73, 77), and a hydraulic pressure for supplying pressure oil to the left and right lock cylinders (61), (71) and the rotary cylinder (56). A pump (25), a changeover switch (36) for switching overhang / retraction of the jib (21),
A crane jib extension having a mode changeover switch (37) for switching to a mode for inserting the left lock pin (63, 67).
In the storage device, when hydraulic oil is supplied from the hydraulic pump (25) to the right lock cylinder (71), the hydraulic oil is also supplied to the left lock cylinder (61). -Storage device.