JPH0340863Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a crane boom, and particularly to a mounting device for a cylinder that extends and retracts the boom.

BACKGROUND TECHNOLOGY As shown in FIG. 9, a hollow inner boom 2 is telescopically fitted into a hollow outer boom 1 which is pivotally connected to a vehicle body so as to be vertically swingable.
It is known that the piston rod 4 of the telescopic cylinder 3 and the cylinder tube 5 are connected by pins 6 and 7 over the inner boom 2 and the inner boom 2.

Problems to be Solved by the Invention The pin 6 is fitted into the boss 8 of the outer boom 1, the pin 7 is fitted into the boss 9 of the inner boom 2, and the inner and outer booms 1 and 2 are of sheet metal welded structure. Therefore, it is difficult to align the centers of both bosses 8 and 9, and since they are eccentric by e, the cylinder 3 cannot be installed parallel to the inner and outer booms 1 and 2. During installation, twisting occurs based on the eccentricity e, and when the piston rod 4 is extended or contracted, the piston does not slide parallel to the cylinder tube 5, which damages the seal between the piston and the inner surface of the cylinder tube 5, causing oil leakage. Leakage may occur or breakage may occur due to excessive force (unbalanced load) being applied to the connection between the cylinder 3 and the inner/outer booms 1 and 2.In addition, if the above-mentioned deviation of the center of the boss is large, In some cases, the cylinder 3 cannot be connected to the inner and outer booms 1 and 2.

Means and action for solving the problem The pin fitted into the cylinder side rod boss is shaped to have a diameter smaller than its inner diameter and a pair of parallel surfaces on both sides in the direction of expansion and contraction of the piston rod, and this pair of parallel surfaces and the cylinder side rod boss The piston rod and the outer boom are connected by tightly fitting a key between the piston rod and the inner circumferential surface of the piston rod, and the pin and the cylinder side rod boss can be firmly fixed so that they do not move slightly in the direction of expansion and contraction of the piston rod.
It is designed to allow relative displacement in a direction perpendicular to the direction of expansion and contraction of the piston rod.

Embodiment Inside an outer boom 10 made of a hollow elongated material with a rectangular cross section, first, second, third, and fourth inner booms 11, 12, 13, and 14 made of a hollow elongated material with a rectangular cross section are arranged in order to be able to expand and contract. 1, 2, 3, and 4 sliding guide bushes 15, 16, 17, and 18 are inserted into the boom of a five-stage telescoping crane.

The first cylinder 20 is connected to the first and second pins 21 and 22 between the outer boom 10 and the first inner boom 11.
The first inner boom 11 and the second inner boom 1
The second cylinder 23 is connected to the second inner boom 12 and the third inner boom 12 by the first and second pins 24 and 25.
A third cylinder 26 is connected to the inner boom 13 by first and second pins 27 and 28, and the fourth inner boom 14 is extended and contracted by first and second ropes 29 and 30.

In other words, the first, second and third cylinders 20, 2
3, 26 cylinder tubes 20a, 23a, 2
A pair of cylinder side tube bosses 3 are installed on both sides of 6a.
1 are fixed respectively, and both side walls 11a, 12a, 1 of the first, second and third inner booms 11, 12, 13 are fixed respectively.
A boom-side tube boss 32 is fixed to each of the boom-side tube bosses 3a, and each of the second
The pins 22, 25, 28 are fitted to connect each cylinder tube 20a, 23a, 26a to the first, second and third cylinder tubes.
It is connected to inner booms 11, 12, and 13.

A connecting rod 33 fixed between both side walls 10a of the outer boom 10 and first and second rods fixed to both side walls 11a and 12a of the first and second inner booms 11 and 12, respectively.
A pair of boom-side rod bosses 36 are fixed to the brackets 34 and 35, respectively, and the first, second, and third
Piston rods 20b of cylinders 20, 23, 26,
Cylinder side rod bosses 27 are fixed to 23b and 26b, respectively, and each cylinder rod boss 3
7 is fitted between each pair of boom-side rod bosses 36, and the first pins 21, 24, 27 are inserted between them.
are fitted, and are prevented from coming off and rotating with a plate 38.

The intermediate portion of each of the first pins 21, 24, 27 that fits into the cylinder-side rod boss 37 has a smaller diameter than the inner diameter of the cylinder-side rod boss 36, and the piston rods 20b, 23b, 2
Both sides of the expansion/contraction direction of 6b are cut out to form a pair of parallel surfaces 39, 39.
9, 39 and the inner peripheral surface 3 of the cylinder side rod boss 37
7a, a pair of keys 40 each having a substantially semicircular cross section are press-fitted and fixed to each of the first pins 21, 2.
4 and 27 and the cylinder-side rod boss 37 are firmly connected so as not to move slightly in the direction of expansion and contraction of the piston rod, and are also connected so that a gap 41 is formed between them in a direction perpendicular to the direction. There is.

Note that a hole 42 facing the first pin 21 is formed in both side walls 10a of the outer boom 10.
Tighten and loosen the bolts 43 and remove the plate 38.
The first pin 21 can be press-fitted and pulled out by attaching and detaching the first pin 21, thereby allowing the first, second, third, and fourth inner booms 11, 12, 1 to be attached and removed from the outer boom 10.
3, 14 can be extracted, and the first, second, third, and fourth booms 11, 12, 13, and 14 can be removed from the
Connected via the second and third cylinders 20, 23, 26, and inserted into the outer boom 10 in that state, the first
The piston rod 20b of the cylinder 20 is connected to the first pin 21
It can be connected to the outer boom 10 with.

Since it is like this, each of the first pins 21, 24, 2
7 and the cylinder side rod boss 37 can be relatively displaced between the key 40 and the parallel surface 39 in a direction perpendicular to the piston rod expansion/contraction direction. It can be absorbed by relative displacement, and no twisting occurs.

Therefore, the piston and sealing material are not damaged and oil leakage occurs, and various parts are not damaged due to excessive force.

In addition, a pair of keys 40 are provided in the direction of expansion and contraction of the piston rod.
Since the piston rods are firmly connected without any slight movement, the piston rods do not rattle and make abnormal noises when expanded or contracted, nor do they cause abnormal wear or damage.

Effects of the invention The inner boom can be extended and contracted with respect to the outer boom 10 by extending and contracting the piston rod of the cylinder.

In addition, the cylinder side rod boss 37 and the pin can be relatively displaced in the direction perpendicular to the direction of piston rod expansion and contraction, so even if the center of the cylinder side rod boss 37 and the center of the boom side rod boss 36 are misaligned, the pin can be fitted smoothly and assembled. The work is easy and there is no possibility of failure to assemble, and since there is no twisting, the piston seal will not be damaged, resulting in no oil leakage or damage to various parts.

Also, the pin and cylinder side rod boss 37 are
Since the piston rod is firmly connected by the key 40 so that it does not move slightly in the direction of expansion and contraction, there is no rattling sound, abnormal wear, or damage when the piston rod is expanded or retracted.

[Brief explanation of the drawing]

1 to 8 show embodiments of the present invention.
The figure is a cross-sectional front view, Figure 2 is a cross-sectional plan view, Figure 3 is a left side view, Figures 4 and 5 are - lines in Figure 1,
- Line sectional view, Figure 6 is a perspective view of Figure 2, Figure 7
8 are a front view and a sectional view of the plate attachment portion of the second pin, and FIG. 9 is a sectional view of a conventional example. 10 is the outer boom, 36 is the boom side rod boss,
37 is the cylinder side rod boss, 39 is the parallel surface, 4
0 is the key.

Claims (1)

[Scope of utility model registration request] The inner boom is telescopically inserted into the outer boom 10, and the cylinder tube of a telescoping cylinder is connected to the inner boom with a pin so as to be swingable in a direction perpendicular to the piston rod expansion and contraction direction. A cylinder side rod boss 37 is provided on the outer boom 10, and a pair of boom side rod bosses 36 are provided on the outer boom 10.
are provided on both sides of the cylinder side rod boss 37, and a pin is fitted over each boss to connect the piston rod to the outer boom 10, and both ends of the pin are fixed to the boom side rod boss 36. Then, insert the middle part of the pin into the cylinder side rod boss 3.
7, and has a shape having a pair of parallel surfaces 39 on both sides in the direction of expansion and contraction of the piston rod,
This pair of parallel surfaces 39 and the cylinder side rod boss 3
7. A boom for a crane characterized in that a key 40 is tightly fitted between the cylinder side rod boss 37 and the inner peripheral surface of the cylinder rod boss 37 so that the cylinder side rod boss 37 can be displaced relative to the pin in a direction perpendicular to the direction of expansion and contraction of the piston rod.