FI97464B - Single-cable grab bucket for discharging bulk goods - Google Patents

Abstract

The invention concerns a single-cable grab bucket for discharge of bulk goods, which comprises lifting members 5 for raising and lowering the grab bucket; a hydraulic cylinder 1 fitted with a piston 2 for opening and closing the grab bucket; a hydraulic circuit 7 which connects a cylinder space 8 above the piston 2 with a cylinder space 9 beneath the piston 2; and a remote-controlled hydraulic valve 4 situated in the hydraulic circuit 7. The hydraulic circuit 7 comprises in addition a non-return valve 3 which, when the empty grab bucket is lowered onto a stack of bulk goods which is to be unloaded, and the hydraulic valve 4 is closed, allows an automatic activation of the hydraulic cylinder 1 in a pre-set position of the grab bucket's filling and tranfer functions. <IMAGE>

Description

97464

Unit rope grab for unloading bulk material.

The invention relates to a unit rope handle according to the preamble of claim 1 for unloading bulk goods.

In addition to the lifting mechanism, the actual grab cranes usually also have a grab closing mechanism. In mobile cranes used in the construction industry, as well as in port cranes, such 10 machinery is usually lacking, and various attempts have been made to resolve the issue when using a grab. Many different types of solutions have been developed for lifting machines that do not have a separate grab opening / closing mechanism, but there are mainly two different types. One of these has a complex lever system constructed in the kah-15 mar, which alternates between the closing and opening positions when the grab is lowered onto the platform. In these, the opening of the grab cannot be performed freely. In addition, such a complex linkage has been shown to be prone to interference and wear. Most commonly, a construction is used in which the closing / opening mechanism, hydraulic or electric, is placed in the grapple itself and the power unit in the crane. This system is expensive and the hydraulic hoses or electrical cables required for the power supply are easily damaged. However, a simple, reliable and effective solution has not been found, judging by the fact that ^ ·; more and more people have switched to the above-mentioned expensive and easily damaged type of power grab} *>>.

DE-C-717032 and DE-C-807543 disclose unit rope grabs according to the preamble of claim 1.

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It is an object of the present invention to provide a relatively simple and reliable grapple for use in hoists without a separate grapple opening / closing mechanism. In order to achieve this object, the grapple according to the invention is characterized by the matters set out in the characterizing part of claim 1.

The grapple solution according to the invention has no internal or external power units, the hydraulic system used in it is completely closed and the control is handled remotely wirelessly, e.g. from a crane. An important advantage of the solution according to the invention is a considerable increase in the service life of the device compared to the solutions used so far, and in addition an important advantage is the possibility to use a grapple in all types of cranes without any prior preparation.

In addition, the grapple solution according to the invention improves occupational safety and operational efficiency thanks to a non-energy-operated non-return valve, which is an integral part of it. When lowering the grab, for example in the hold of a ship, usually on a very uneven pile, it may tilt or tip over during the tuning phase. This is dangerous in 20 situations where there are stevedores in the hold. An accustomed crane driver reacts to this immediately by tightening the hoisting rope and possibly moving the grab to another position. The non-return valve used in the solution according to the invention ensures that in such a dangerous situation the driver does not have to react to a steering movement other than a lifting movement.

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The invention will now be described with reference to the accompanying drawings, in which:. . ·. Fig. 1 schematically shows a prior art grab arrangement with the bucket part closed, Fig. 2 shows the grapple shown in Fig. 1 in its opened state 35, and Figs. 3 and 4 show the invention. an embodiment of a hydraulic cylinder for use in a grapple arrangement according to

The grapple solution according to Figures 1 and 2 comprises lifting members 5 connected to the upper part of the cylinder 1. Inside the cylinder 1 there is a piston 2, the piston rod of which is connected to the opening members of the bucket part (cavity) 6. The cylinder space 8 above the piston 2 is connected to the cylinder space 9 below the piston 2 by a hydraulic circuit 7 comprising a remote controlled hydraulic valve 4 (e.g. radio controlled solenoid valve) and a non-return valve 3. The grab works as follows: to unload the goods in the bucket part 6 valve 4, whereby the piston 2 15 of the cylinder 1 is pushed into the extended position (Fig. 2), and the bucket part is emptied. The function of the valve 4 is preferably such that it remains open only as long as it is given a control command, in which case the goods to be unloaded can be unloaded by sprinkling if desired. After emptying the bucket part, the grapple 20 is transferred onto the unloaded mass stack and lowered until it rests on the base. In this case, when the lifting member 5 is lowered, the cylinder 1 can move downwards with respect to the piston 2, whereby the hydraulic fluid flows through the non-return valve 3, the hydraulic valve 4 is closed, from the space 8 above the piston 25 to the space below the piston 9. • ·:. · Position. In this case, when lifting the grapple with the lifting member 5 »a # · #. the bucket part 6 is filled with the bulk material to be unloaded and at the same time • · the bucket part closes (Fig. 1). The grapple is emptied 30 by opening the hydraulic valve 4 by remote control, whereby the pressurized hydraulic fluid can flow from the space 9 below the piston 2 to the space 8 above the piston 2. Such ·.?. the grab arrangement allows the cylinder 1 to be tuned to the required space for filling and closing the bucket part automatically by simply lowering the grab onto the pile to be dismantled. Remote control is only required during the opening phase of the bucket part 6.

4 97464

Depending on the type of grapple, positioning a normal hydraulic cylinder may be difficult. In such cases, a double-acting telescopic cylinder 10 shown in Fig. 3 can be used according to the invention, the operation of which is essentially the same as that of the one-piece cylinder shown in Figs. 1 and 2. Such a telescopic structure allows the cylinder to be placed in a smaller space than a one-piece cylinder.

In order to increase the efficiency of the cylinder used in the grapple according to the invention, a compensating tank 11 provided with a rubber film and a breather 12 can be attached to the upper part of the cylinder, which compensates for the difference in oil volumes on different sides of the pistons. Such a surge tank 11 is suitable for both one-piece cylinder-15 blades and a telescopic cylinder.

Figure 4 further schematically shows the control means 14,15 of the telescopic cylinder 10 for holding the telescopic cylinder straight.

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Claims (2)

5 97464 A unit rope grab for unloading bulk material, comprising lifting means (5) for raising and lowering the grab; a hydraulic cylinder (1) provided with a piston (2) for opening and closing the grapple; a hydraulic circuit (7) connecting the cylinder space (8) above the piston (2) to the cylinder space (9) below the piston (2); and a remote-controlled hydraulic valve (4) in the hydraulic circuit (7), the hydraulic circuit (7) further comprising a non-return valve (3) which allows the hydraulic cylinder (4) to be lowered when the empty grapple is lowered onto the unloaded mass stack and the hydraulic valve (4) is closed. (1) automatically tuning to the 15 positions required by the grab filling and transfer functions with the cylinder (1) pushed downward by gravity relative to the piston (2) with the lifting members (5) in an unloaded condition, allowing the non-return valve (3) to move the hydraulic fluid from above the piston (2); 8) in the space (9) below the piston (2), characterized in that the cylinder is a telescopic cylinder (10). Grapple according to Claim 1, characterized in that a membrane-operated hydraulic fluid expansion tank (11) is arranged in the upper part of the cylinder (1, 10). 25 i 1. • ** ♦ 1 »» I 1 ·% ·% »• · 1 ·« »» • «•« · «· · • · · · $ i ': 6 97464