JPH028952Y2 - - Google Patents

Description

[Detailed explanation of the invention] (1) Technical field The present invention relates to a multi-stage boom used in crane vehicles, aerial work vehicles, etc., and in particular, the intermediate boom is extended and contracted by a hydraulic cylinder, and the tip boom is extended and contracted using a cable such as a wire. The present invention relates to a multi-stage telescopic boom that can be extended and retracted.

(2) Prior Art In the conventional boom of the above-mentioned type, each stage boom had a rectangular cross section as shown in Figure 1, so the cable for extending and retracting the first stage boom 3 was connected between the base boom 1 and the intermediate boom 2. However, securing the space for passing the cable in this way would make the outer size of the base boom 1 unnecessarily large (on the contrary, the outer dimensions of the base boom 1 would be (If the size of the intermediate boom 2 is kept to the necessary limit, the dimensions of the intermediate boom 2 can only be made small.) Also, due to installation space issues, if the cable end fixing fitting a of the reduction cable is attached to the bottom of the boom, the cable can be pulled out to the bottom of the base boom. Since the hole (b) must be provided, there was a problem in that the strength of the boom was not ensured and the design was disadvantageous.

(3) Purpose of the invention The present invention provides a boom structure that is advantageous in terms of the above-mentioned boom external dimensions and boom strength.

(4) Structure of the invention In this invention, hydraulic cylinders are installed between three adjacent booms that are inserted in a telescopic manner, and the base boom 1 and the middle boom 2 are connected to each other. Between the booms 3, an extension cable whose both ends are fixed to the tip of the base boom 1 via two extension drive sheaves provided at the tip of the middle boom 2 is connected to the rear of the front boom 3. The base stage boom 1 is suspended from a folding guide fixed at the end, and is connected to the base stage boom 1 via two reduction drive sheaves installed at the base end of the middle stage boom 2.
In a multi-stage telescopic boom in which a retraction cable with both ends fixed to the tip end is suspended from a folding guide fixed to the rear end of the first stage boom 3, the base stage boom is hollowed out as shown in Fig. 2. The middle-stage boom and the first-stage boom are each formed into a hollow pentagonal cross-section with a downwardly convex bottom plate, and the middle-stage boom and the first-stage boom are formed with a rectangular cross section. The reduction cable is inserted and installed in two spaces along the axis of the boom having a triangular cross section at two locations on the left and right formed between each bottom plate, and the reduction cable is installed by passing through the space along the boom axis line at two locations on the left and right that have a triangular cross section, and In space,
A sliding pad that slides into contact with the bottom plate of the middle stage boom is arranged on the upper surface thereof, and rope end fasteners each having a through hole along the boom axis are fixed to the end of the base stage boom tip side of the reduction cable. It is configured to be inserted and fixed into the through hole.

Since the space A formed as described above has a triangular cross-section, there is sufficient space to pass the reduction cable, so there is no need to make the outer shape of the base boom 1 larger than necessary, and the space A has a triangular cross section. Since the cable end stopper can also be placed inside A, there is no need to provide a cable extraction hole on the bottom surface of the base stage boom 1.

In addition to the three-stage boom, the above-mentioned configuration can also be applied between three adjacent boom cylinders at the intermediate stage or base stage (or first stage) in a boom with four or more stages.

(5) Embodiment A first embodiment in which the present invention is applied to a three-stage telescoping boom will be described below in Fig. 3. This embodiment is a boom used for a truck-mounted crane, and as shown in FIG. 3, the base end boom 1 is equipped with a fulcrum pin insertion boss 11 and a bracket 12 for connecting a luffing cylinder (not shown) at the rear, and an intermediate boom. 2. The tip boom 3 is inserted into each. Between the intermediate boom 2 and the base boom 1, the rod side end of the cylinder tube 4a of the hydraulic cylinder 4 and the piston rod 4b are connected with pins, respectively, and the intermediate boom 2 has brackets on both sides of its tip. 2a,
Two extension drive sheaves 5, 5' are pivotally supported on 2a',
There are two reduction drive sheaves 8, 8' inside the rear end.
is pivotally supported and attached to the side wall 22. The tip boom 3 has a boom head with a pulley for suspending a hook attached to the head, and folding guides 7 and 10 for extension and retraction cables are fixed to the rear end. For the cable using wire rope or chain, the extension cable 6 is suspended around the folding guide 7, guided toward the boom tip, and then wrapped around the extension drive sheave 5, 5' to the top of the proximal end of the boom 1. The reduction cable 9 is suspended from the folding guide 10 and then from the reduction drive sheave 8, 8', guided toward the boom tip, and fixed to the lower inner surface of the proximal end of the boom 1. ing. With the above configuration, in this three-stage boom, when the hydraulic cylinder 4 extends, the intermediate boom 2 extends, the extension cable 6 is pulled by the intermediate boom 2, the tip boom 3 similarly extends, and the hydraulic cylinder 4 also extends. When it is retracted, the intermediate boom 2 is retracted and the retraction cable 9 is retracted by the intermediate boom 2.
is pulled, and the tip boom 3 is simultaneously retracted.

Now, to explain the main parts based on FIG. 4, in the boom of this embodiment, the cross-sectional shape of the base end boom 1 is a hollow rectangle, and the cross-sectional shapes of the intermediate boom 2 and the tip boom 3 are similar to each other, with the bottom plate facing downward. It has a convex hollow pentagonal shape, and when the boom is inserted, a space A with a triangular cross section is surrounded by the lower part of the bottom plate 1a and side plate 1b of the proximal boom 1 and the V-shaped bottom plate 2b of the intermediate boom 2. Two locations will be formed along the boom axis. On the other hand, sheave 8 for reduction drive,
8' is installed so that the sheave grooves 8a, 8a' are located in the space A in the vertical cross section, and as a result, the reduction cable 9 suspended on the folding guide 10 at the rear end of the tip boom 3 is Reduction drive sheave 8,
After being hung around the boom 8', it can be guided toward the tip of the boom through this space A. The reduction cable 9 that has reached the boom tip in this manner is fixed in the same space A in the boom tip device by a cable end fastener 11 shown in FIG. That is, this rope end fastener 11 as a whole is space A.
It is a triangular prism 11a having approximately the same cross section as the base boom 1, and is bolted into the space A at the tip of the base end boom 1, and has a sliding pad 11b fixed to its upper surface that makes sliding contact with the outer surface of the intermediate boom 2. A through hole 11 is provided approximately in the center of the triangular prism 11a.
C is perforated and the cable end fitting 9a of the reduction cable 9 is attached to this hole.
is passed through and fastened with a nut 11d.

(6) Effects of the invention In this invention, a hollow pentagonal cross-section intermediate stage boom is inserted into a hollow rectangular cross-section base stage boom, and a reduction cable is inserted into the space formed in this state along the boom axis line of a triangular cross-section. Since it is designed to be inserted through the base boom and the middle boom, the shape of the middle boom can be increased even though it is a multi-stage telescopic boom in which the reduction cable is inserted between the base boom and the middle boom. If the inner height of the base boom is the same, the inner height of the base boom can be smaller than the conventional example, and conversely, if the inner height of the base boom is the same, the inner height of the middle boom can be increased, which is advantageous for ensuring strength in terms of boom design. be.

In addition, since the end of the reduction cable was fixed to the cable end fastener fixed in the triangular space at the tip of the base boom, there was no need to provide a cable extraction hole on the underside of the base boom. Therefore, this aspect is also advantageous in terms of strength.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the conventional boom structure, Figure 2
The figure is a conceptual diagram showing the configuration of the present invention, Figure 3 is a partial cross-sectional side view showing the entire embodiment of the present invention, and Figure 4 is a line AA in Figure 3 showing the main part of the embodiment. arrow view,
FIG. 5 is a perspective view showing the cable end fastener of this embodiment. 1; Base position boom (base end boom of the embodiment),
2; Middle boom (middle boom of the embodiment); 3;
Advance boom (tip boom of the embodiment), 4; Hydraulic cylinder, 5, 5'; Sheave for extension drive, 6; Cable for extension, 7; Folding guide, 8, 8'; Sheave for reduction drive, 9; Reduction drive rope; 10; folding guide; A; space having a triangular cross section.

Claims (1)

[Scope of utility model registration request] Between the three adjacent booms 1, 2, and 3 inserted in a telescopic manner, a hydraulic cylinder 4 is installed in the base boom 1 and the middle boom 2, and between the base boom 1 and the front boom 3. The middle boom 2
Two extension drive sheaves 5 provided at the tip of the
The extension cable 6, which has both ends fixed to the tip of the basic boom 1 via the cable 5', is hung around the folding guide 7 fixed to the rear end of the first boom 3, and then the middle boom 2 is attached.
Two reduction drive sheaves 8 provided at the base end of the
In a multi-stage telescopic boom, a retraction cable 9 whose both ends are fixed to the tip of the base stage boom 1 via a base stage boom 1 is suspended from a folding guide 10 fixed to the rear end of the front stage boom 3. The stage boom 1 has a hollow rectangular cross section, the middle stage boom 2 and the front stage boom 3,
Each bottom plate is formed into a hollow pentagonal cross section with a downward convexity, and when the middle boom is inserted into the base boom, the cross sections at two places on the left and right are formed between the bottom plates of the middle boom and the base boom. The reduction cable 9 is installed through a triangular space along the axis of the boom, and the top surface of the reduction cable 9 is in sliding contact with the bottom plate of the middle boom in the left and right triangular space at the tip of the base boom. The sliding pads 11b are arranged, and the cable end fasteners 11 each having a through hole 11c along the boom axis are fixed, and the end of the base boom tip end of the reduction cable 19 is prevented from being inserted into the through hole 11c. A boom structure characterized by the fact that it can be worn.