JPH025665B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a support device for a counterweight truck in a large crane. (Prior Art) In large cranes, a counterweight truck 40 is sometimes used as shown in FIG. 7 to prevent overturning. This trolley 40 is equipped with a counterweight 41 on the upper part and wheels 42 on the lower part.As shown in FIG. It is connected to a counterrope 6 that hangs down from a mast 5 that supports the boom 4 of the crane main body 1. Therefore, it is necessary for this dolly 40 to be able to travel together with the crane body 1 by following the movement of the crane body 1 by the crawler traveling body 3, that is, the straight movement (forward or backward movement) and the lateral movement (movement to the left or right). It is also necessary to enable the crane body 1 to rotate integrally with the rotating body 2 about the rotation center C ₀ . Further, in this type of large crane, the length of the mast 5 and the length of the counterweight support rope 6 change depending on the length of the boom 4. For this reason,
Counterweight support rope 6 for truck 40
In order to facilitate the connection of the carriages 40, it is desirable that the height h above the ground of the carriage 40 is adjustable. Therefore, carts as shown in FIGS. 9 and 10 have been proposed. This truck 40 has wheel supports 43a to 43d supported at four locations at predetermined intervals in the front, rear, left and right directions in the lower part thereof, respectively, so as to be able to freely turn around turning centers Ca to Cd perpendicular to the truck 40. Suspension links 45a to 45d are supported vertically swingably at the lower portions of the wheel supports 43a to 43d via pivots 44a to 44d, respectively, and suspension links 45a to 45d are supported at the tips of each of the links 45a to 45d via axles 46a to 46d, respectively. Wheel 42a
~42d is rotatably supported, and each wheel support rest 4
Suspension cylinders 47a-4 provided between 3a-43d and the links 45a-45d
7d adjusts the height h of the truck 40, and each of the wheel supports 43a to 43d is adjusted to the center of rotation Ca by the steering cylinders 48a to 48d.
It is possible to change (steering) the direction of the wheels 42a to 42d by turning around Cd. In the case where a link type suspension is used in this way, each axle 46a to 46d and each wheel 4 are
The grounding points 2a to 42d are connected to the respective wheel supports 43a to 4.
3d, and the amount of eccentricity l' will also change as the height h of the truck 40 is adjusted. However, in the conventional truck 40, each wheel 42
a to 42d suspension links 45a to 45
d are arranged in the same direction, that is, when the trolley 40 moves straight, the pivot shafts 44a to 44d of the links are located forward in the direction of travel, and the axles 46a to 46d are located at the rear in the direction of travel, and during steering, for example, when the trolley 40 moves straight, When changing (steering) the direction of the wheels 42a to 42d from the state to the traversing state or vice versa, each wheel support 43a to 4
3d are turned in the same direction around the turning centers Sa to Cd by the steering cylinders 48a to 48d, and the grounding points of the wheels 42a to 42d remain eccentric by an eccentric amount l' from the turning centers Ca to Cd. The truck 40 is turned and displaced in the same direction, and the truck 40 moves in the opposite direction to the turning direction of the wheel supports 43a to 43d by an amount corresponding to the eccentricity l'. The revolving structure 2 of the crane body 1 moves (swings), causing the suspended load to sway, creating a very dangerous problem. (Purpose of the Invention) The present invention has been made to solve these problems, and it is possible to maintain the cart in a fixed position without moving the cart even if the direction of the wheels of the counterweight cart is changed (steering). To provide a support device for a counterweight truck in a large crane that can be safely used by smoothly steering the crane while the crane is stopped, preventing swinging of a suspended load without adversely affecting the revolving body of the crane body. (Structure of the Invention) The present invention is a counterweight truck that is connected to the rear part of a revolving body of a crane main body in a large crane, and in which wheels are mounted at a plurality of locations at predetermined intervals in the front, back, left and right sides of the bottom of the truck. The support body is rotatably supported around a rotation center perpendicular to the truck, and a suspension link is supported at the lower end of each wheel support body via a pivot shaft so as to be swingable in the vertical direction. wheels are rotatably supported through respective axles, and a suspension is provided between each link and each wheel support body to adjust the height of the cart above the ground by vertically swinging the suspension link. A cylinder is provided, and the above-mentioned truck is provided with a steering mechanism for turning and steering each wheel support body about the above-mentioned turning center, and the suspension links of the corresponding left and right wheels are arranged in opposite directions with respect to each turning center. The wheel supports are arranged so that the suspension links of the front and rear wheels facing each other are opposite to each other with respect to each turning center as a reference. (Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 6. In the figure, 10 is a counterweight truck,
The plane shape is formed into a horizontally elongated rectangular shape, and the revolving body 2 of the crane main body 1 shown in FIGS. 7 and 8 is formed on the upper surface.
Connecting brackets 11 and 12 for connecting the connecting rod 7 and wire rope 8 connected to the counterweight support rope 6, and a connecting bracket 13 for connecting the counterweight support rope 6 are provided protrudingly, and a plurality of columns 14 for preventing the counterweight from falling off are detachably attached. A counterweight 15 is mounted on the trolley 10. At the bottom of the truck 10, wheels are installed at a total of four locations, front and rear, left and right, via wheel supports 16a to 16d. Each of these wheel supports 16a to 16
d has the same structure, and hereinafter, the structure of one wheel support 16a will be explained based on FIG. , c, and d. In FIG. 3, the wheel support 16a is
0 through a swing bearing 17 so as to be able to swing freely around a swing center Za, and this wheel support 16
A suspension link 20a is supported in the lower part of the suspension link 20a via a bearing member 18a and a pivot 19a so as to be swingable in the vertical direction, and a pair of wheels 22a and 23a are rotatably supported in the middle part of the link 20a via a wheel 21a. pins 24a, 2 are supported between the wheel support 16a and the link 20a.
A suspension cylinder 26a is suspended via 5a. In this case, each wheel 22a, 23a
may all be idle wheels, but in the illustrated example, one of the wheels 22a and 23a
is a drive wheel driven by a drive motor 27a and a chain transmission mechanism 28a provided at the tip of the link 20a, and the other wheel 23a is an idling wheel. On the other hand, the rod end of a steering cylinder 31a is connected to a steering portion 29a provided on the upper part of the wheel support 16a by a connecting pin 30a, and steering is performed by expansion and contraction of this cylinder 31a. Note that the head side of the steering cylinder 31a is connected to a predetermined location of the truck 10 by a connecting pin 32a (the fourth
(see figure). 33a is a swivel joint. Each wheel support 16a configured as described above.
16d is arranged with respect to the trolley 10 as follows. First, the turning center of each wheel support 16a to 16d
Regarding the positional relationship between Za and Zd, as shown in Figure 4, the wheels that correspond to each other on the front, rear, left and right sides should be taken into account so that they do not interfere with each other during steering.
Distances La and Lb, Lc and Ld from the center line Y along the longitudinal direction of 0 to each turning center Za to Zd of the left and right corresponding wheel supports 16a and 16b, 16c and 16d
are the same (La = Lb, Lc = Ld), and the wheel supports 16a, 16c, 16b correspond to each other in the front and rear from the center line X along the left and right direction of the truck 10.
and the distance Wa from each turning center Za to Zd of 16d.
Wc, Wb and Wd are equal (Wa=Wc, Wb
= Wd). In the illustrated example, by setting the above distances as La=Lb, Lc=Ld Wa=Wc, Wb=Wd, and La>Lc>Wa, the stability of the cart 10 is ensured while The depth W in the front-rear direction is made smaller than the width L in the left-right direction of the truck 10, thereby making the truck 10 smaller. In this case, the above distances may be arranged so that La=Lb=Lc=Ld Wa=Wc=Wb=Wd. On the other hand, each of the wheel supports 16a to 16d and suspension links 20a to 20d (however,
20b to 20d are not shown; the same applies hereinafter);
In other words, the positional relationships between the respective axles 21a to 21d and the pivot shafts 19a to 19d of the suspension links 20a to 20d (however, 19b to 19d are omitted, the same applies hereinafter) are such that they correspond to each other on the left and right, and correspond to each other in the front and back. Those who do this are turning their comrades against each other. That is, in this embodiment, when the truck 10 moves straight, the axle 21a of the front left wheel support 16a and the axle 21d of the rear right wheel support 16d are eccentric forward with respect to the turning centers Za and Zd during steering, Axle 21b of front right wheel support 16b
The axle 21c of the rear left wheel support 16c is arranged eccentrically rearward with respect to the turning centers Zb and Zc during steering. Also, during steering, each wheel support 16a~
16d are configured to simultaneously turn in the same direction around the turning centers Aa to Zd, and the telescoping hands of the cylinders 31a to 31d for the steering are arranged so that the cylinders 31a, 31c, and 31 which are adjacent to each other in the front and rear
b and 31d have the same expansion and contraction properties, and cylinders 31a, 31b and 31 which are adjacent to each other on the left and right
c and 31d are arranged so that their expansion and contraction directions are opposite. In the illustrated example, when the truck 10 moves straight, the front left cylinder 31a and the rear left cylinder 31c are in an extended state, and the front right cylinder 31b and the rear right cylinder 31d are arranged in a contracted state. In addition, all the expansion/contraction positions of the cylinders 31a to 31d may be arranged in the opposite direction to that shown in the drawing. Next, the operation of the above device will be explained. The above-mentioned trolley 10 has a counterweight 15 on the upper part.
7 and 8 on each of the connecting brackets 11 and 12 provided on the top thereof.
A connecting rod 7 whose tip end is connected to the revolving body 2 of the crane main body 1 shown in the figure and a rear end of a wire rope 8 are connected, and a counterweight support rope 6 is connected to a connecting bracket 13 for use. In this case, the height H of the truck 10 is adjusted by swinging the suspension link 20a by the suspension cylinder 26a of each wheel 22a to 22d, 23a to 23d, and the connection work of the counterweight support rope 6 is performed. make it easier. The crane main body 1 is driven by the crawler traveling body 3, that is, is moved straight or sideways, and is turned by a turning mechanism (not shown). When turning, the vehicle is steered as shown in FIG. 5 and FIG. 6, respectively. Each wheel support 16a at this time
The directions of the steering cylinders 31a to 16d are shown in Table 1, and the expansion and contraction relationships of the steering cylinders 31a to 31d are shown in Table 2.

【table】

[Table] In Table 2, turning is based on when the vehicle is traveling sideways. When moving the crane body 1 straight in this way,
Each wheel support 16a to 16d and each wheel 22a
22d, 23a to 23d are held as shown in FIG.
8d, the crane body 1 is rotated in synchronization with the traveling speed of the crane body 1 by the traveling body 3. As a result, the truck 10 is moved straight together with the crane main body 1. In this case, the trolley 10 does not move straight while being towed by the crane main body 10, but moves straight on its own, so that the crane main body 10 is smoothly moved straight without being overloaded. Next, when moving the crane body 1 sideways, the steering cylinders 31a, 3
1c and reduce the steering cylinder 3.
By stretching 1b and 31d, each wheel support 1
6a to 16d are all turned in the same direction (clockwise in Fig. 4) and steered to the state shown in Fig. 5. In addition, when steering from the traversing state shown in FIG. 5 to the straight-ahead state shown in FIG. 4, each of the wheel supports 16a to 16d is turned in the opposite direction (counterclockwise direction in FIG. 5). In this case, each wheel 22a to 22d and 23a
The grounding points of ~23d are the wheel supports 16a~16.
They are eccentric by l with respect to the turning centers Za to Zd of d, but the eccentric directions are set in opposite directions for the left and right corresponding ones and the front and rear corresponding ones with respect to the bogie 10, respectively. By turning each of the wheel supports 16a to 16d in the same direction, the amount of eccentric movement of each wheel support body 16a to 16d is canceled out by the corresponding ones, and the bogie 1 is rotated during steering.
0 movement is suppressed to a minimum, the influence on the crane body 1 is also reduced, and swinging of the suspended load is thereby prevented. In addition, by turning all the wheel supports 16a to 16d in the same direction during steering as described above, the relationship between the rotational direction of each drive wheel 22a to 22d and the traveling direction (straight, traverse) of the bogie 10 can be changed. can be kept constant, driving wheel 2
There is no need to provide a hydraulic circuit switching circuit for 2a to 22d. Also, during steering, the number of cylinders 31a and 31c to be retracted and the number of cylinders 31b to be extended,
31d, the fluctuation in the oil level of the oil tank in the hydraulic circuit for that cylinder is small, and the difference in time required for steering each wheel support 16a to 16d is reduced, resulting in efficient steering. . Note that a motor-driven steering mechanism may be used in addition to the above-mentioned cylinder as the steering mechanism. (Effects of the Invention) As described above, the present invention allows the suspension links of the wheels, which are supported through the wheel supports at several locations on the front, rear, left and right sides of the lower part of the bogie, to be aligned with the center of rotation of the wheel supports. Since the front and rear corresponding parts and the left and right corresponding parts are arranged in opposite directions, the swing of each suspension link prevents the wheel axle from being eccentric with respect to the center of rotation of the steering wheel. By steering each wheel support in the same direction, the amount of eccentric movement of each wheel support can be canceled out between the corresponding ones, and the amount of movement of the bogie during steering can be minimized. This makes it possible to minimize the influence on the crane body and prevent the suspended load from shaking, making it extremely safe to use.

[Brief explanation of drawings]

Fig. 1 is a front view of an embodiment of the present invention when the bogie is running horizontally, Fig. 2 is a side view thereof, Fig. 3 is a sectional view of essential parts showing the support structure of the wheel support body, Figs. Figures 5 and 6 show the straight, lateral, and horizontal movement of the truck according to the present invention.
A plan view showing the positional relationship of the wheels during each turning operation, FIG. 7 is an overall side view showing the relationship between a general large crane and a truck, FIG. 8 is a schematic plan view thereof, and FIG. 9 is a Side view showing a conventional trolley, 1st
Figure 0 is a schematic plan view showing the positional relationship of the wheels. 1... Crane main body of a large crane, 2... Revolving body, 3... Crawler traveling body, 4... Boom, 5
...Mast, 6...Counterweight support rope, 10...Counterweight truck, 15...Counterweight, 16a-16d...Wheel support body, 17...Swivel bearing, 20a...Suspension link, 21a-21d ...Wheels, 26
a...Suspension cylinder, 27a to 27d
... Drive motor, 28a to 28d... Chain transmission mechanism, 31a to 31d... Steering cylinder, Za to Zd... Turning center.

Claims (1)

[Claims] 1. A counterweight truck connected to the rear of the revolving body of the crane main body of a large crane, in which wheel supports are installed perpendicularly to the truck at multiple locations at predetermined intervals on the front, back, left and right sides of the bottom of the truck. A suspension link is supported at the lower end of each wheel support via a pivot shaft so as to be swingable in the vertical direction, and a wheel is attached to each suspension link via an axle. Rotatably supported,
A suspension cylinder is provided between each of the links and each of the wheel supports, and the suspension cylinder swings the suspension link in the vertical direction to adjust the height of the truck above the ground. A steering mechanism is provided that steers by turning around a center, and the suspension links of wheels corresponding to each other on the left and right are oriented in opposite directions with respect to each turning center, and the suspension links of wheels corresponding to each other in the front and rear are provided. A support device for a counterweight truck in a large crane, characterized in that each wheel support is arranged so that the wheel supports are oriented in opposite directions with respect to each turning center.