JPH07277680A - Fall preventive device of crane truck - Google Patents

Abstract

PURPOSE:To increase the maximum suspending capacity of a crane extremely by making it possible to store the main boom within the car width of a crane truck, and reducing the maximum transmitting stress as well as increasing the moment arm length to transmit the bending force between a main beam and an auxiliary beam. CONSTITUTION:In the transmission of the bending force between a main beam and an auxiliary beam, a joint 13 is connected to the main beam 4 a little loose by pins 14 and the like, so that the lower surface of the upper jaw of the box form joint 13 provided at the base end of the auxiliary beam 10 held by the second jack 15 of a crane truck which can be lifted up, is abutted and engaged to the top surface of the main beam 4 at the base side from the first jack 6, and the upper surface of the lower jaw 11 of the joint 13 is abutted and engaged to the lower end of the extension 9 of the main beam 4 at the front side from the first jack 6. As a result, the body frame of the crane truck lifted up from the ground surface is maintained horizontally in cooperation with the first jack 6 of the crane truck which cannot be lifted up. An earth plate 6c of the first jack 6 which can be mounted and demounted can be stored in a storing box 40 installed to the lower side of the auxiliary beam 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fall prevention device for a mobile crane having a large maximum lifting capacity.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 9, a guide member laterally mounted on a vehicle body frame is slidably fitted between a laterally extended position of a crane vehicle and a retracted position within the vehicle width. The left and right main outriggers each having the first jack E vertically attached to the tip of each main beam C, and the pin G at the tip of each main beam.
A fall prevention device for a crane vehicle provided with an outrigger device in combination with an auxiliary outrigger in which a second jack F is vertically attached to the tip of a supplementary beam D that is detachably attached by means of Japanese Utility Model Publication No. 61-39752. However, since the main beam C must be retracted and stored within the vehicle width when the mobile crane travels on the road, the main auxiliary beams C and D
The moment arm length H between the upper and lower pins G, G when transmitting the bending force between them cannot be increased, and there is a drawback that the dramatic improvement in the maximum lifting capacity of the crane is hindered.

[0003]

The problem to be solved is that the main beam can be stored within the width of the crane vehicle, and the moment arm length for transmitting the bending force between the main and auxiliary beams is increased. At the same time, the maximum transmission stress due to the pin connection between the main and auxiliary beams is reduced, and the maximum lifting capacity of the crane can be improved to about 500 tons.

[0004]

According to the present invention, when the bending force is transmitted between the main and the auxiliary beams, the upper surface of the main beam extends in abutment engagement with the lower end of the main beam extension portion which is extended shorter than the first jack of the main beam. A lower jaw, a box-like joint having an upper jaw whose lower surface abuts and engages with the top surface of the main beam on the base side of the first jack, and a box-shaped joint with the upper and lower jaws opened downwardly, The box-shaped joint is fixed integrally with the box-shaped joint, the size of the opening is set so that the first jack mounting portion of the main beam can be inserted into and removed from the box-shaped joint, and the supplementary beam is added to the main beam. The most main feature is that a loose connecting means is provided between the main beam and the main beam so as to be separable.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a front view of an embodiment of the present invention showing a longitudinal section of a main part, and FIG. 2 is a plan view thereof.
A turntable of a crane swivel in which a floor plate 1a having a full width of the vehicle is integrally welded to the top of a box-shaped body frame 1 of an automobile that runs longitudinally in the front-rear direction, and a detachable multi-stage telescopic boom is cantilever-supported (not shown). No. 2) is detachably mounted on the body frame 1 and has the same structure as before. Reference numeral 2 is a wheel of an automobile suspended from the body frame 1.

A hollow main beam 4 having a rectangular cross section, which is slidably fitted in a guide member 3 which is horizontally installed on the lower side of the vehicle body frame 1, is moved by a hydraulic cylinder 5 to the side of a crane vehicle shown in the figure. The right main outrigger 7 is formed by sliding the sliding position between the overhang position and the storage position in the vehicle width, and vertically attaching the first hydraulic control jack 6 to the tip of the main beam. A box for integrally supporting the guide members 3 of the main outriggers 7 in opposite directions capable of projecting to the left and right of the crane car in order to lift the crane car horizontally, and to respectively support both ends of the guide member combination. It is also the same as before that the shaped bracket 8 is welded to both sides of the body frame before and after the turntable mounting portion to form the outrigger device.

Reference numeral 9 denotes an extension portion of the main beam 4 which is shorter than the first jack 6 and is extended. When the bending force is transmitted between the main beam and the supplementary beam 10 added to the main beam, the extension portion of the main beam 4 is provided. A lower jaw 11 whose upper surface abuts and engages with the lower end of 9;
The box-shaped joint 13 is provided with an upper jaw 12 whose lower surface abuts and engages with the top surface of the main beam on the base side of the jack 6, and the upper and lower jaws 12 and 11 are opened downward. The opening is integrally fixed to the end, and the opening has a size such that the first jack mounting portion of the main beam 4 can be inserted into and removed from the box-shaped joint 13. Moreover, the main beam 4 and the box-shaped joint 13 at the supplementary beam joining position are connected by a pin (which may be a bolt) 14 which can be freely inserted and removed.
The upper and lower jaws 12 and 11 are connected loosely so that they are pressed against the main beam 4. The reference numeral 45 designates a hanging fitting of the auxiliary beam 10.

Therefore, since the horizontal distance L (see FIG. 4) between the upper and lower jaws 12 and 11 can be made larger than the height M of the first jack mounting portion of the main beam 4, the ground plates 6c and 15c, respectively.
The first jack 6 of the main beam and the auxiliary beam 10 which are grounded
The upper and lower jaws 1 of the box-shaped joint are used for cargo handling work in which the crane truck is lifted up and supported by the second jack 15 at the tip.
Not only the moment arm length for transmitting the bending force between 2, 11 and the main beam 4 is significantly increased from the conventional one,
The contact between the upper and lower jaws and the main beam becomes a substantially surface contact due to bending strain and the like, so that the lifting capacity of the crane for lateral suspension can be significantly improved.

FIG. 7 shows an embodiment of the hydraulic circuit of the device of the present invention, in which the directional control valve 17 connected to the discharge port of the hydraulic pump 16 is used.
The high pressure side oil chambers (upper oil chambers) 6a and 15a at the time of grounding driving of the first jack 6 and the second jack 15 are connected in parallel to the A port of each of the ports through the intermittent valves (selection valves) 18 and 19, respectively. Further, to the port B of the direction switching valve 17, low pressure side oil chambers (lower oil chambers) 6b and 15b are connected in parallel when the first jack and the second jack are grounded. Reference numerals 20 and 21 are pilot-operated check valves inserted into the oil passages to the upper oil chambers 6a and 15a, respectively, for holding the first and second jacks in the crane vehicle lifting position, and 22, 23, respectively. Is a hydraulic hose detachably connected to the main beam 4 so that the auxiliary beam 10 can be attached to and detached from the main beam 4, 24 and 25 are quick joints at both ends of the hydraulic hose, and 26 and 27 are main beams with respect to the guide member 3 4 is a hydraulic hose connected to the hydraulic oil passage of the first jack 6 so that it can be expanded and contracted. 28 and 29 are upper and lower oil chambers of the other first and second jacks, and ports A and B of the direction switching valve 17. Similarly, a branch oil passage connected in parallel is shown.

Reference numeral 30 denotes a main relief valve connected to the discharge port of the pump 16. A vent port 31 of the main relief valve 30 is connected to a small relief valve 3 having a low set pressure via a switching valve 32.
3 or a small relief valve 34 with a high set pressure can be connected. Therefore, when the switching valve 32 is in the neutral position shown in the drawing, the vent port 31 is connected to the tank T and the pump 16 is operated without load. However, the switching valve is switched to operate the small relief valves 33, 34. If either of them is connected to the vent port 31, the set pressure of the main relief valve 30 is limited to the set pressure of the small relief valve.

Accordingly, the set pressure of the small relief valve 33 is lowered so that the main outrigger mounting portion of the crane vehicle cannot be lifted when the first jack 6 is driven to be grounded, and the first or second
If the setting pressure of the small relief valve 34 is set high so that the main outrigger mounting portion can be lifted when the jack is grounded, the crane can be operated by the second jack 15 of the auxiliary beam 10 that is connected to the main beam 4. After raising the car horizontally, the first
The jack 6 is grounded so that the crane vehicle is not lifted up, and the bending and bending of the main beam 4 and the auxiliary beam 10, that is, the boom inclination is excessive during the side loading and unloading work in which the hanging load of the crane is extremely large. It is possible to eliminate the risk that the crane safety device will operate in an untimely manner and prevent the load of the rated load from being lifted.
Use the jack 6 to lift the body frame 1 horizontally,
It is also possible to carry out a light cargo handling work and to attach / detach the crane swivel to / from the vehicle body frame.

This is because the set pressure of the main relief valve can be switched between high and low depending on which of the small relief valves 33 and 34 is connected to the vent port 31 of the main relief valve 30 and the valve is normally closed. Two sets of on-off valves 18 in position,
Depending on which one of 19 is opened, A of the directional control valve 17,
According to the fact that the first jack 6 or the second jack 15 can be selectively connected to the B port.

In the embodiment shown in FIG. 1, a part of the grounding board 6c of the first jack 6 projects laterally from the tip of the main beam extension 9 to the side of the crane vehicle, and when the main beam 4 is stored in the vehicle width, Since a part of the grounding board projects outside the vehicle width, as shown in FIGS. 5 and 6, a spherical head that can be engaged with the lower surface of the U-shaped angle 35 that is concentrically projected and fixed on the grounding board 6c. 36, the first
It is fixed to the lower end of the piston rod 37 of the jack and the U
The grounding plate 6c is attached to the lower end of the piston rod so as to be separable by horizontal movement by closing the opening of the letter-shaped angle 35 with the insertable / removable pin 38, and the contracted horizontal position of the grounding plate 6c of the first jack. When the storage box 40 that can be stored by moving is attached to the lower surface of the auxiliary beam 10 and the auxiliary beam is added to the tip of the main beam, the suspension board 39 hung on the crane hook as shown in FIG. After suspending the supplementary beam 10 in which it is stored and connecting it to the main beam 4 as shown in FIG. 3, the grounding board 6c in the storage box 40 is horizontally moved and attached to the piston rod 37 as described above. Change.

The supplementary beam 10 shown in the drawing is provided with a bracket 41 located at the back side of the storage box 40, and the bracket 41 and the bracket 42 on the grounding plate 6c are connected to each other by a U-shaped angle 35.
By connecting with the pin 38 that has been pulled out, the ground board 6
c is fixed in the storage box. It is apparent from the above description that when the pin 14 is pulled out and the auxiliary beam is detached from the main beam, the grounding plate 6c supported in advance by the piston rod 37 is horizontally moved and stored in the storage box.

The upper end of the first jack 6 is the main beam 4 as described above.
Although the embodiment in which the cylinder portion of the first jack 6 is housed in the main beam 4 as shown in FIG. 8 has been described above, the upper jaw 12 of the box-shaped joint 13 is described. Can be extended to the base end of the complementary beam 10. In this embodiment, the upper and lower jaws 12, 11
Since it is necessary to make the gap between the main beam 4 and the main beam 4 fitted between them relatively large, an empty space 43 is provided in the upper jaw 12, and the top of the box-shaped joint 13 is formed into a hollow arm shape. However, when the bending force is transmitted between the main supplementary beams 4 and 10, the free end of the hollow arm-shaped upper jaw 12 is bent to make surface contact with the top surface of the main beam 4. In FIG. 8, members designated by the same reference numerals as those in FIG. 1 indicate corresponding members, and the lower jaw 11 having a relatively small thickness is reinforced by a reinforcing member 44 welded to the lower surface thereof. .

[0016]

As described above, in the fall prevention device for a mobile crane according to the present invention, the upper jaw of the box-shaped joint at the base end of the auxiliary beam is more than the first jack when the bending force is transmitted between the main and auxiliary beams. The joint is loosely connected to the main beam so that the main beam on the base side abuts and engages, and the lower jaw of the joint abuts and engages on the lower end of the main beam extension beyond the first jack. do it,
Since the length of the moment arm for transmitting bending force between the main and auxiliary beams is increased and the maximum stress due to the bending force is made relatively small, the maximum lifting capacity of the crane can be dramatically improved. If it is possible, and the retractable grounding board of the contracted first jack is moved horizontally, it can be stored in the storage box attached to the lower surface of the auxiliary beam.
The weight of the mobile crane on the road can be reduced by the weight of the grounding board to improve the lifting capacity of the crane, and the amount of the main beam that can be stowed within the width of the vehicle to the side of the vehicle increases. Therefore, by changing the set pressure of the main relief valve, which limits the pump discharge hydraulic pressure, to high or low with a small relief valve,
When the ground output of the jack is selectively switchable between the output that can lift the main outrigger mounting part of the crane vehicle and the output that cannot lift the crane, the first jack can be replaced by the second jack of the supplementary beam. It is possible to function as an intermediate support for preventing the lifted crane vehicle from falling over, or to perform light cargo handling work promptly without attaching a supplementary beam, so that the cargo handling function of the crane truck can be increased.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of the present invention showing a main part in a vertical section.

FIG. 2 is a plan view of FIG.

FIG. 3 is a vertical cross-sectional front view of essential parts showing a stored state of a grounding board.

FIG. 4 is a vertical sectional front view showing a method of attaching / detaching the auxiliary beam to / from the main beam.

FIG. 5 is a detailed view of a main part when the grounding board is stored in the storage box of the auxiliary beam.

FIG. 6 is a plan view of the grounding board of FIG.

FIG. 7 is a hydraulic circuit diagram of first and second jacks.

FIG. 8 is a vertical cross-sectional front view of the essential parts of another embodiment of the present invention.

FIG. 9 is a front view of a main part of a conventional device.

[Explanation of symbols]

 1 body frame 2 wheels 3 guide member 4 main beam 6 first jack 7 main outrigger 9 main beam extension 10 auxiliary beam 11 lower jaw 12 upper jaw 13 box joint 14 pin 15 second jack 30 main relief valve 32 switching valve 33 Small relief valve with low setting pressure 34 Compact relief valve with high setting pressure 40 Storage box

Claims (4)

[Claims] 1. A leading end of a main beam slidably fitted between a laterally extended position of a crane vehicle and a retracted position within a vehicle width in guide members laterally mounted on a body frame, respectively. Outriggers combining the left and right main outriggers each having the first jack attached vertically and the auxiliary outriggers each having the second jack vertically attached to the tip of the auxiliary beam detachably attached to the tip of each main beam. A fall prevention device for a mobile crane equipped with a device, wherein an upper surface abuts on a lower end of a main beam extension portion which is extended shorter than the first jack of the main beam when transmitting bending force between the main and auxiliary beams. A lower chin to match,
A box joint having an upper jaw whose lower surface abuts and engages with the top surface of the main beam closer to the base than the first jack is integrally fixed to the base end of the auxiliary beam with the upper and lower jaws opened downward. The size of the opening is set so that the first jack mounting portion of the main beam can be inserted into and removed from the box-shaped joint, and the box-shaped joint at the supplementary beam joining position to the main beam and the main beam A fall prevention device for mobile cranes, characterized in that a loosely connecting means is provided between and freely separated. 2. A beam for accommodating the cylinder part of the first jack in the main beam, and extending the upper jaw of the box-shaped joint to the base end of the auxiliary beam so that the upper jaw has its free ends both the main and auxiliary beams. 2. The fall prevention device for a crane vehicle according to claim 1, wherein the device is configured as a hollow arm that comes into surface contact with the top surface of the main beam when a bending force is transmitted therebetween. 3. A grounding board is attached to the lower end of the piston rod of the first jack so as to be separable by horizontal movement, and a part of the grounding board is projected to the side of the crane vehicle from the tip of the main beam extension to contract. The fall prevention device for a mobile crane according to claim 1, wherein a storage box capable of storing the grounding board of the first jack by horizontal movement is attached to the lower surface of the auxiliary beam. 4. A main relief valve is connected to a pump discharge port of a hydraulic circuit capable of selectively controlling the first and second jacks,
A switching valve capable of selectively connecting any of small relief valves having different set pressures is provided at the vent port of the main relief valve, and the main outrigger mounting portion of the crane vehicle is lifted up when the first jack is grounded. The main relief valve setting pressure can be limited by a small relief valve with a low setting pressure, or the setting pressure of the main relief valve can be set high so that the main outrigger mounting part of a crane vehicle can be lifted. The fall prevention device for a mobile crane according to claim 1 or 2, wherein the pressure is reduced by a small relief valve.