RU2730730C1 - Operating method of boom self-propelled crane and device for implementation thereof - Google Patents

Abstract

FIELD: lifting devices.SUBSTANCE: invention relates to jib cranes. Boom lifting device comprises counterweight and A-like frame. Auxiliary counterweight is installed on transport trolley connected to rotary platform by two telescopic crossarms.EFFECT: increasing and maintaining constant crane lifting capacity at change of boom reach.2 cl, 9 dwg

Description

The invention relates to structural elements of self-propelled boom cranes, and in particular to devices and a method of operation for lifting and lowering crane booms in cases significantly exceeding the rated lifting capacity of the crane.

It is advisable to use the invention to maintain high mobility of the crane and multiple increase in its passport capacity in most existing jib cranes by upgrading them.

This is especially true for pneumatic-wheeled cranes, including automobile cranes and truck cranes.

Known hoisting cranes, the boom device of which includes a boom, counterboom, two traverses located symmetrically relative to the vertical plane passing through the boom axis, counterboots and the vertical axis of rotation of the turntable.

The ends of each crosshead are connected to a transport cart loaded with an auxiliary counterweight.

To ensure rigidity, the carts are connected by a spacer.

Each joint of the traverse is connected by a cable to the bogie to the counterboom, the position of which is changed by the boom chain hoist (Germany 3019220, France 2457245, GB, USA 2050295 A1)

Disadvantages:

1. High labor intensity of the crane preparatory work.

2. Limited mobility.

3. The need for reassembly and disassembly when moving from one construction site to another.

4. The lifting capacity of the crane is variable when the boom reach is changed.

There is a known method of increasing the carrying capacity (RF 2593179, 28.04.2014), in which the carrying capacity remains constant when changing the boom reach.

Disadvantages:

1. Limited mobility of the crane.

2. The increased length of the crane makes it difficult to turn and move the crane.

3. Complexity of crane control.

Technical challenge:

1. Create the most optimal way to increase and maintain a constant lifting capacity of the crane when changing the boom.

2. Reduce weight and dimensions along the length of the crane.

3. Maintain high mobility of the crane.

4. Simplify crane control.

The solution to the technical problem can be carried out in two directions:

A) for cranes with straight booms and jib pulley, it is necessary to install an A-frame and an auxiliary counterweight;

B) for cranes with a hydraulic drive of telescopic booms, it is sufficient to install an auxiliary counterweight, since in most cases the limiting factor for increasing the lifting capacity is not the strength of the boom, but the load stability of the crane.

In addition to boom 2, the design of the slewing platform 1 of the crane includes telescopic racks 3, 4 of the A-shaped frame 5, which provides a multiple reduction in the load on the boom 2 of the crane.

To maintain the load stability of the crane, in addition to the factory counterweight, it is necessary to install an auxiliary counterweight 7 loaded on the transport trolley 8 rigidly connected to two telescopic traverses 9, 10 (Fig. 1, 3) with a turntable 1.

In this case, the following condition must be met: the restoring moment M ₁ is equal to or greater than the overturning moment M ₂ , i.e.

M ₁ ≥M ₂

Extending the counterweight is a setting motion.

In the process of lifting loads of various weights, the counterweight 7 overhang can remain unchanged based on the above condition.

The diagram (Fig. 1) shows the initial position of the boom 2 and the A-frame 5 and their working position.

The lifting and lowering of the load 11 is carried out by cargo winches 12, 13 and their cargo ropes 15, 16.

Changing the boom 2 is performed by a winch 14 and a boom rope 17 (Fig. 1).

Changing the departure of the auxiliary counterweight 7 is made by telescopic traverses 9, 10 (Fig. 1, 3), mounted on the transport trolley 8 on split supports 39, 40, 41, 42 (Fig. 1, 1-1, 3, 5).

When towing, the transport trolley 8 is supported by paired cylinders 18-21 (Fig. 1, 1-1, 2), and when the turntable rotates or when the crane is turned, it leans through jacks 22-31 on paired rollers 32-38, 50-52.

The movement of these rollers occurs along a radius relative to the central vertical axis 49 of the turntable 1 when it rotates or when the crane is turning.

Each of the traverses 9, 10 ends with welded flanges 43, 44, with conical protrusions 45, 46 (Fig. 1, 3, 4) to ensure the rigidity of the connection with the turntable 1.

Flanges 43, 44 are connected to flanges 47, 48 made in the form of conical funnels mating with conical protrusions 45, 46 of flanges 43, 44 (Fig. 1, 3, 4).

Jacks 22-31 and the aforementioned conical surfaces simplify the connection of the transport trolley 8 and the turntable 1, ensuring the alignment of the traverses 9, 10, flanges 43, 44 and 47, 48.

In turn, the flanges 47, 48 through the plates 59, 60 are welded to the turntable.

The second design involves the installation of telescopic traverses 9, 10 along the transport cart 8 during its towing (Fig. 6).

In this case, the traverse 9 is supported by the jack 53, and the traverse 10 is supported by the jack 54.

In this case, the jacks 53, 54 perform not only the lifting and lowering of the traverses 9, 10, but also ensure their rotation, respectively, along the radius R R (Fig. 6, 7).

Before installing traverses 9, 10 in working position, the upper part of supports 55-58 traverses 9, 10 must first be dismantled.

After the traverses have been installed, the position shown in FIG. 7 all upper parts of supports 55-58 must be installed in their design locations.

Figure 8 shows the fastening and installation of the traverse 9 on the jack 53 and the traverse 10 on the support 57.

The fastening and installation of traverses 9, 10 on all other supports and on the jack 54 is similarly made.

This scheme of operation and installation of traverses 9, 10 can significantly increase the reach of the auxiliary counterweight and, accordingly, increase the crane's lifting capacity.

Example.

It is necessary to determine the permissible weight of the load Q _A when installing the A-shaped frame (see Fig. 9).

Let's set the scale of forces 1 cm = 100 tf.

1. Determine the compression force of the arrow R Art.

According to the rated lifting capacity, at a given boom outreach, the crane can lift a load weighing Q = 300 tf.

Let's construct a segment AL equal to the force Q = 300 tf.

Let us expand the force Q - into two components in the direction of the boom AB and the direction of the boom rope BL

When the directions of the arrow and the arrow rope intersect, we get point B.

Thus, the compression force of the boom R st = 650 tf is determined.

2. Determine the permissible weight of the load Q _A on the boom when installing the A-frame.

We expand the force R st in the direction of the boom rope VK and the direction of the weight of the load KA. The intersection of these directions will define point K.

The resulting segment of the spacecraft gives the permissible weight of the load Q _A = 580 tf, which actually consists of the sum of two weights, i.e. Q _A = Q + ΔQ.

Q _A = 300 + 280 = 580 tf i.e. Q _A ≈2Q

Conclusion: The lifting capacity of the crane increases with an increase in the angle between the boom and the jib rope (due to the installation of the A-frame).

Positive effect

1. Multiple reduction of boom load.

2. The height dimension will allow for the smooth movement of the crane without dismantling the boom device.

3. The growth of the crane's lifting capacity does not cause a significant increase in the specific metal consumption coefficient determined by the ratio of the crane's weight to the lifting capacity.

4. The lifting capacity of the crane remains constant when the luffing radius is changed.

5. Maintaining high mobility of the crane.

Claims (2)

1. Arrangement of a boom system for lifting and lowering crane booms, including an auxiliary counterweight or simultaneously an auxiliary counterweight and an A-frame, characterized in that the auxiliary counterweight is mounted on a transport trolley, rigidly connected by means of flanges with tapered surfaces, by two telescopic traverses with a rotary crane platform. 2. A method of operation of a self-propelled jib crane for lifting and lowering crane booms, including the installation of an auxiliary counterweight and an A-frame, characterized in that the auxiliary counterweight is mounted on a transport trolley, rigidly connected by flanges having conical surfaces by two telescopic cross-arms with a rotary the platform of the crane, while providing a variable and necessary counterweight overhang and at the same time installing an A-shaped frame in the rear of the platform.

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