JPH0238803B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is utilized in the field of a hydraulic cylinder for extending and retracting a multi-stage crane boom in which several boom tubes are inserted into a telescope. In this field, when multiple hydraulic cylinders are installed in a crane boom, each
Rather than arranging the hydraulic cylinders between the boom cylinders, the number of assembly steps is reduced if the two hydraulic cylinders are connected in a flexible manner by some method and then arranged between the boom cylinders. There are fewer bosses, connecting pins, etc., making the installation space more compact. It is increasingly being adopted for these reasons.

The present invention relates to a system for connecting two hydraulic cylinders when disposed within such a crane boom.

(Prior Art) The prior art in this field includes the one shown in FIG. This conventional technology uses two hydraulic cylinders 4 and 5.
are arranged in parallel and U is attached to the body of those hydraulic cylinders.
The belt-shaped metal fittings 6, 7, which appear to be in the shape of a letter, are wound so as to butt against each other, and the butt parts are connected with bolts to fix them together.The fixation is achieved by friction between the band-shaped metal fittings 6, 7 and the cylinder body. It is designed to be held by force and the frictional force of the abutting portions connected by bolts.

By the way, when a crane boom is lifting a load near its maximum crane capacity, the boom angle of elevation is increased to lift the load as shown in Figure 2, so the force acting in the direction of the boom axis reaches from several tons to several tens of tons. In addition, when a suspended load is hoisted high in the air and then lowered at high speed and suddenly stopped midway, an impact load twice that amount is applied. In such a case, in the conventional technology, the force can only be supported by frictional force, and the band-shaped fittings 6 and 7 themselves are easily deformed by the force acting on the boom, so the hydraulic cylinder 4 is It has a defect that it tends to shift in the longitudinal direction. Therefore, if the above-mentioned severe use is repeated, the misalignment between the hydraulic cylinders 4 and 5 will gradually increase, causing damage to the fixed piping between the hydraulic cylinders 4 and 5, and damage to the proximal boom of the intermediate boom. There was a problem that the insertion position was twisted, leading to the boom being crushed.

In addition, in the manufacturing process for assembling the hydraulic cylinder into the boom cylinder, it is not possible to secure the belt-shaped metal fittings after the hydraulic cylinder is inserted into the boom cylinder. Although both hydraulic cylinders 4 and 5 must be secured with metal fittings, the securing positions of both hydraulic cylinders 4 and 5 must be centered very precisely so that the pin hole at the tip of the piston rod is perfectly aligned with the boss on the boom tube side when the piston rod is fully retracted. There is a problem that must be kept. Otherwise, the later assembly process inside the boom will be delayed. However, when lashing with band metal fittings, it is difficult to find a reference point for the lashing position, so centering is difficult unless a fairly large jig is used, which requires a large amount of work or requires large-scale assembly equipment. There were difficulties in terms of manufacturing costs.

(Object of the invention) The present invention solves the problems encountered in the above-mentioned prior art, and can easily absorb excessive force acting on the boom.
To provide a method for connecting a plurality of hydraulic cylinders, which can eliminate misalignment between installed hydraulic cylinders and damage to a piping system caused by this, and can simplify assembly process work and reduce the number of work steps.

(Configuration of the Invention) The configuration of the present invention will be explained based on FIG. Reference numeral 1 designates a first hydraulic cylinder disposed between the proximal boom a and the intermediate boom b, which includes a cylinder tube 11, a piston 12, and a piston rod 13, and has an oil chamber 1 divided by the cylinder tube 11 and the piston 12.
4. It has an oil chamber 15 divided by the piston rod 13 and the piston 12. In addition, oil grooves 16 and 17 are bored in the piston rod 13.
6 communicates with the oil chamber 14, and the oil groove 17 communicates with the oil chamber 15. 18 is a port for connecting both oil grooves 16 and 17 to a hydraulic power source. 3 is a hole through which a pin 3P for fixing to the base end boom a is passed, and 4 is a hole through which a pin 4P is to be passed through for fixing to the base of the intermediate boom b. Reference numeral 5 denotes a flange erected near the tip of the cylinder tube 11, and is formed integrally with the cylinder tube 11, and its flange surface 51 is formed parallel to a plane perpendicular to the cylinder axis direction. Further, oil grooves 54 and 55 are bored in this flange 5, and bolt holes 52 for passing connecting bolts 53 are bored in parallel to the cylinder axis direction. 6 is a mounting seat provided at the rear end of the cylinder tube 11, and bolt 8
A female thread 61 for screwing 1 is cut. Oil chamber 1
4 and the opening end of the oil groove 54 of the flange 5, an oil feed pipe 9 is installed with each end welded.

2 is a second hydraulic cylinder disposed between the intermediate boom b and the tip side boom c, and the cylinder tube 2
1, a piston 22, and a piston rod 23, and has an oil chamber 24 defined by the cylinder tube 21 and the piston 22, and an oil chamber 25 defined by the piston rod 23 and the piston 22. Reference numeral 7 denotes a hole through which a pin 7P for fixing to the tip of the boom on the tip side is passed. Reference numeral 26 is the bottom surface of the rear end of the cylinder tube 21, which is the joint surface with the flange surface 51, and oil grooves 27 and 28 are bored in the thick part thereof.
Also, a female thread 56 into which the connecting bolt 53 is screwed is bored. 2P is oil groove 27, 28 and oil groove 5
4 and 55. This is a sealing member interposed on the joint surface between 4 and 55. 8 is a mounting seat provided at the tip of the cylinder tube 21 and has a bolt through hole 82 bored therein. Oil chamber 2
5 and the open end of the oil groove 27 at the rear end of the cylinder tube 21, an oil feed pipe 10 is installed with each end welded. The first hydraulic cylinder 1 and the second hydraulic cylinder 2 configured in this way have the rear end bottom surface 26 of the cylinder tube 21 connected to the flange surface 51.
The mounting seat 8 is fixed to the mounting seat 6 with a dowel bolt 81, and the mounting seat 8 is fixed to the mounting seat 6 with a dowel bolt 81. It is now possible to connect and fix them so that they are constrained to each other.

FIG. 4 is a schematic diagram showing an arrangement example in which a hydraulic cylinder according to the present invention is applied to a three-stage boom. The first hydraulic cylinder 1 connects the tip of the piston rod 13 between the proximal boom a and the intermediate boom b.
The cylinder tube 11 is connected to the base with a pin 3P, and the tip of the cylinder tube 11 is connected to the intermediate boom base with a pin 4P. It is fixed to the hydraulic cylinder 1 and the tip of the piston rod 23 is connected to the tip of the tip boom c by a pin 7P. Note that the hydraulic cylinder according to the present invention can be applied to a four-stage boom or a boom of five or more stages equipped with a boom tube that retractably accommodates the proximal end boom a in FIG. Even in the case of a four-stage boom or a boom of five or more stages, which is provided with a boom cylinder that is retractably housed in the boom c, it can be similarly arranged between three appropriate boom cylinders. In any case, by telescopically moving the hydraulic cylinders 1 and 2 arranged in this way, the intermediate boom b and the distal end boom c are designed to be telescopically moved.

(Effects of the Invention) The effects of the present invention will be explained in comparison with the prior art. In the present invention, the boom axis component force of the lifted load acting on the boom is directly received by the integral component of the hydraulic cylinder. When lifting a heavy object by raising the boom elevation angle as shown in Figure 2,
The boom axis component force acts on the first hydraulic cylinder 1 via the distal end boom C and the second hydraulic cylinder 2, and is transmitted to the proximal boom a. When force is transmitted from the second hydraulic cylinder 2 to the first hydraulic cylinder, it is received by the flange 5, which is an integral component protruding orthogonally to the direction of force action, so that the second hydraulic cylinder 2 and the first hydraulic cylinder
There is no room for misalignment between the hydraulic cylinder 1 and the hydraulic cylinder 1. However, in the case of the prior art, when the boom axis component force is transmitted between the two hydraulic cylinders 4 and 5, the frictional force between the hydraulic cylinder 5 and the band-shaped fitting, the frictional force of the abutting portion of the band-shaped fitting, and the frictional force between the band-shaped fitting and Since it is transmitted only by the frictional force between the hydraulic cylinders 4 (see Figure 1), the force of several tons to several tens of tons cannot be supported, and a shift occurs between the hydraulic cylinders 5 and 4 in the boom axis direction. Moreover, if the band-shaped metal fittings become deformed due to long-term use, the deviation becomes critical and causes damage to the piping connecting the hydraulic cylinders 4 and 5, oil leakage, and even breakage of the boom. Therefore, the present invention makes it possible to provide a highly reliable crane boom in this respect.

Further, according to the present invention, the process of assembling and assembling the hydraulic cylinders is extremely simple and can be performed with a small number of man-hours. This is because in the hydraulic cylinder of the present invention, the finished dimensions of the flange surface 51 and the rear end bottom surface 26 of the cylinder tube 21 are determined in the machining process using a machine tool, so that in the assembly process it is sufficient to simply tighten the bolts. This not only simplifies the manufacturing process of the crane boom, but also allows the hydraulic cylinder to be easily disassembled and reassembled at the repair stage after shipment, allowing repairs to be carried out not only at the manufacturing factory but also at a service factory. In this respect, the present invention has disadvantages in centering work in the assembly process, requires a large number of assembly man-hours, and cannot be repaired satisfactorily unless the manufacturing factory is equipped with special jigs. The benefits are far greater.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the prior art, Fig. 2 is an explanatory diagram of the usage state of a crane boom, which is the field of application of the present invention, Fig. 3 is a configuration diagram of the present invention, and Fig. 4 is a three-stage crane boom of the present invention. FIG. 2 is a schematic diagram illustrating the state of the force acting on the crane boom, showing an example in which the crane boom is applied and arranged. 1; first hydraulic cylinder, 2; second hydraulic cylinder, 5; flange, 51: flange surface, 6, 8;
Mounting seat.

Claims (1)

[Claims] 1. In order to extend and retract the three boom cylinders fitted into the telescope, connect the first hydraulic cylinder 1 between the proximal boom and the intermediate boom with the tip of its piston rod 13 connected with a pin 3P to the base of the proximal boom, The tip of the cylinder tube 11 is connected with a pin 4P to the base of the intermediate boom, and the second hydraulic cylinder 2 is connected between the intermediate boom and the tip side boom with the tip of its piston rod 23 connected with a pin 7P to the tip of the tip boom.
and connect the cylinder tube 21 to the first hydraulic cylinder 1.
The first hydraulic cylinder 1 has a flange 5 integrally formed near the tip of the cylinder tube 11 with a flange surface 51 parallel to a plane perpendicular to the cylinder axis direction. The second hydraulic cylinder 2 has a rear end bottom surface 26 of the cylinder tube 21 formed on the joint surface with the flange surface 51, and a mounting seat 6 is provided at the rear end of the cylinder tube 11. A mounting seat 8 facing the mounting seat 6 is provided at the distal end, and the flange surface 51 of the flange 5 and the rear end bottom surface 26 of the cylinder tube 21 are connected to each other, and the flange 5 and the rear end of the cylinder tube 21 are connected to each other. and the mounting seats 6 and 8 are connected with bolts and fixed together.