JPH0680792U - Multi-stage telescopic boom - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a multi-stage telescopic boom capable of sufficiently shortening the length in the fully contracted state. An outer end of a cylinder rod 14b of a telescopic cylinder 14 provided in an innermost inner boom 13 is pivotally attached to an outer tab 11 and a cylinder rod 14b side of a cylinder tube 14a is pivotally attached to an outermost inner boom 12. Has been done. The rollers 19 that roll on the inner surface 13a of the innermost inner boom 13 are provided on the left and right of the rear end of the cylinder tube 14a. For this reason, the inner boom can be moved deeper in the contraction with respect to the outer boom than in the case where the rear end portion of the cylinder tube 14a is provided with the roller, and the multi-stage telescopic boom 10 can be moved.
Can be shortened in the fully contracted state.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a telescopic (nested) multi-stage telescopic boom.

[0002]

[Prior art]

 For example, a multi-stage telescopic boom 30 provided in an aerial work vehicle as shown in FIG. 3 includes a first boom (outer boom) 31 that is freely attached to a vehicle body and can be telescopically inserted into the first boom. The second boom (outermost inner boom) 32 and the third boom (innermost inner boom) 33 that is telescopically inserted into the second boom are telescopically (nested). To be done. In such a multi-stage telescopic boom 30, each telescopic boom is extended and retracted by using the operation of the telescopic cylinder 34 incorporated in the boom and the pulley mechanism including a sheave and a wire (both not shown) provided in the boom. Done.

The expansion and contraction of the second boom 32 with respect to the first boom 31 is directly performed by the operation of the expansion and contraction cylinder 34 including the cylinder rod 34b and the cylinder tube 34a. The telescopic cylinder 34 is provided in the internal space of the third boom 33, and the outer end of the cylinder rod 34b is pivotally attached to the vehicle body mounting portion side (lower end side) of the first boom 31. The cylinder rod side of the tube 34a is pivotally attached to the lower end side of the second boom 32. As a result, when the telescopic cylinder 34 is telescopically operated, the second boom 32 telescopes with respect to the first boom 31.

Expansion and contraction of the third boom 33 with respect to the first and second booms 31, 32 is performed by using a pulley mechanism including sheaves and wires. The pulley mechanism is composed of a sheave attached to the inside of the tip side surface of the second boom 32 and a wire wound around the sheave. One end of the wire is attached to the first boom 31 and the other end is It is attached to the third boom 33. In such a pulley mechanism, when the second boom 32 extends with respect to the first boom 31, the other end of the wire is pulled in the extension direction as the sheave moves in the extension direction. It moves in the extension direction with respect to the second boom 32.

Therefore, when the telescopic cylinder 34 is provided in the inner space of the third boom 33 as described above, the inner surface 33a of the third boom 33 and the telescopic cylinder 34 slide when the boom is telescopic. It will be. For this reason, the roller 39 is provided at the end (rear end) of the cylinder tube 34a opposite to the cylinder rod side so that the lower surface of the telescopic cylinder 34 and the inner surface 33a of the third boom 33 do not directly slide. There is.

[Problems to be solved by the device]

However, in such a multi-stage telescopic boom 30, there are cases where the hydraulic equipment 41 is provided at the inner tip of the third boom 33. In this case, when the boom is contracted, the roller 39 provided at the rear end of the telescopic cylinder 34 and the hydraulic device 41 interfere with each other. Therefore, when the boom is contracted, the hydraulic device 41 immediately before the hydraulic device 41 interferes with the roller 39. It can only be reduced. Therefore, when the roller 39 is attached so as to project from the cylinder tube 34, there is a problem that the length of the multi-stage telescopic boom 30 in the fully contracted state cannot be sufficiently shortened.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a multi-stage telescopic boom capable of sufficiently shortening the length in the fully contracted state.

[0008]

[Means for Solving the Problems]

 To achieve the above object, in the multi-stage telescopic boom of the present invention, a telescopic cylinder for telescopically expanding the boom is provided in the innermost inner boom. The outer end of the cylinder rod is pivotally attached to the outer tab, and the cylinder rod side of the cylinder tube is pivotally attached to the outermost inner boom. Then, rollers that roll on the inner surface of the innermost inner boom are provided on the left and right of the end of the cylinder tube opposite to the cylinder rod side.

[0009]

[Action]

 In such a multi-stage telescopic boom, when the inner boom is contracted with respect to the outer boom, there is nothing protruding at the rear end of the telescopic cylinder provided inside the inner boom, so the tip of the inner boom does not protrude. It does not interfere with the equipment provided in the. Therefore, the inner boom can be moved deeply into the outer boom.

[0010]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows an aerial work vehicle 20 including a multi-stage telescopic boom 10 according to the present invention. The body 1 of the work platform 20 is provided with a swivel base 2 which is capable of horizontally swiveling, and a multi-stage telescopic boom 10 mounted on the upper part of the swivel base 2 is pivoted on the swivel base 2 in an independent manner. The mounted first boom (outer boom) 11, the second boom (outermost inner boom) 12 that is retractably inserted into the first boom 11, and the second boom 12 is extendable and retractable. And a third boom (innermost inner boom) 13 inserted into the telescope (telescopically). A workbench 5 is attached to the tip of the third boom 13, and an operator who rides on the workbench 5 swings the swivel base 2 and raises and lowers the multistage telescopic boom 10 to extend and retract at an arbitrary height. Can be moved to.

Here, the telescopic operation of the second boom 12 with respect to the first boom 11 in the multi-stage telescopic boom 10 is directly performed by the telescopic operation of the telescopic cylinder 14 incorporated in the boom. On the other hand, the expansion / contraction operation of the third boom 13 with respect to the first boom 11 and the second boom 12 is performed by the extension and reduction pulley mechanisms (both not shown) built in the first boom 11 and the second boom 12. Be seen.

The extension pulley mechanism is composed of a sheave rotatably attached to the inside of the tip side surface of the second boom 12 and a wire wound around the sheave. One end of the wire is fixed to the base end of the first boom 11, and the other end of the wire is fixed to the base end of the third boom 13. Therefore, when the second boom 12 extends relative to the first boom 11, the other end of the wire is pulled in the same direction as the sheave moves in the extension direction, and the third boom 13 moves in the extension direction. Let Further, in the multi-stage telescopic boom 10, a reduction pulley mechanism (not shown) having the same structure is provided, and the third boom 13 is moved along with the reduction operation of the second boom 12 with respect to the first boom 11. The booms 11 and 12 are contracted.

As shown in FIG. 1, the telescopic cylinder 14 includes a cylinder tube 14a and a cylinder rod 14b, and tube bearings 14c into which cylinder tube pivot pins 17, 17 are inserted on the left and right of the cylinder tube 14a. , 14c are provided, and a rod bearing 14d into which the rod pivot pin 18 is inserted is provided at the tip of the cylinder rod 14b. Since the third boom 13 is housed inside the second boom 12, the cylinder tube 14a is located in the internal space of the third boom. Therefore, when the boom 10 is expanded and contracted by the expansion and contraction operation of the expansion and contraction cylinder 14, the cylinder tube 14a pivotally attached to the second boom 12 slides on the inner surface 13a of the third boom 13. Therefore, the rear end of the cylinder tube 14a is provided with a roller for preventing damage to the cylinder tube 14a during sliding.

The workbench 5 attached to the tip of the boom 10 is kept horizontal at the tip of the third boom (the rear end of the telescopic cylinder 14) on which the telescopic cylinder 14 slides. There is provided a leveling cylinder 4 for Therefore, when the boom 10 is contracted, the rear end of the telescopic cylinder 14 slides on the inner surface 13a of the third boom 13 in the direction of the leveling cylinder 4. Therefore, when the boom 10 is contracted, the size of the fully contracted state is the size until just before the rear end of the telescopic cylinder 14 and the leveling cylinder 4 interfere with each other. For this reason, if the roller is provided so as to project from the telescopic cylinder 14, the length of the boom 10 in the fully contracted state cannot be shortened sufficiently.

Therefore, in the multi-stage telescopic boom according to the present invention, the roller is attached as follows. This roller is composed of a pair of left and right rollers 19, 19 and is provided at the end (rear end) of the cylinder tube 14a opposite to the cylinder rod 14b side. The rollers 19 and 19 are rotatably attached to roller holding members 20 and 20 provided on the cylinder tube 14a so as to protrude from the lower surface of the cylinder tube 14a. As a result, when the multi-stage telescopic boom 10 is extended or retracted, the roller 19 rolls on the inner surface 13a of the third boom 13, the telescopic cylinder 14 is not damaged, and the multi-stage telescopic boom 10 can be smoothly extended and retracted. Become. Since the roller 19 does not protrude beyond the rear end of the cylinder tube 14a, the length of the boom 10 in the fully contracted state can be shortened.

Therefore, even when the entire multi-stage telescopic boom 10 in the fully retracted state is viewed as a whole, the dimension in the longitudinal direction can be made smaller by the amount that the third boom 13 is deeply contracted into the second boom 12. That is, the function as a multi-stage telescopic boom that is as short as possible in the fully retracted state and as long as possible in the fully extended state can be fully exerted.

In addition, in the above-mentioned embodiment, the case of the boom which can be laid down is explained, but in this case, since the inner surface of the inner boom on which the telescopic cylinder slides is only the bottom surface, the roller is installed from the bottom of the telescopic cylinder. It is supposed to be provided in a protruding manner. However, in the case where there are two sliding surfaces, for example in the case of a vertical lifting type boom, a roller should be provided at a position opposite to the position of the roller provided in the above embodiment. You may

Further, in the above embodiment, the three-stage telescopic boom has been described, but the multi-stage telescopic boom according to the present invention is not limited to the three-stage telescopic boom, and has more stages. It may be one or two-stage type. In the case of a two-stage multi-stage telescopic boom, the telescopic cylinder operates to directly extend and retract the boom, so the inner boom and telescopic cylinder do not slide when the boom is extended or retracted. The inner boom and telescopic cylinder slide when inserting the telescopic cylinder into the boom. Therefore, even a two-stage multi-stage telescopic boom needs to have a roller at the rear end of the telescopic cylinder.

[0019]

[Effect of device]

 As described above, in the multistage telescopic boom according to the present invention, the outer end of the cylinder rod of the telescopic cylinder provided in the innermost inner boom is pivotally attached to the outer tab, and the cylinder rod side of the cylinder tube is the outermost inner rod. It is pivoted to the boom. The rollers that roll on the inner surface of the innermost inner boom are provided on the left and right of the rear end of the cylinder tube. Therefore, the inner boom can be retracted deeper relative to the outer boom than in the case where a roller is provided at the rear end of the cylinder tube, and the length of the multi-stage telescopic boom in the fully retracted state can be shortened. You can Therefore, the function required for the multi-stage telescopic boom, which is as short as possible in the fully retracted state and as long as possible in the fully extended state, can be fully exerted.

[Brief description of drawings]

FIG. 1A is a plan sectional view of a multi-stage telescopic boom according to the present invention in a fully contracted state, and FIG. 1B is a side sectional view.

FIG. 2 is a side view of an aerial work vehicle equipped with the multi-stage telescopic boom.

FIG. 3A is a plan sectional view of a conventional multi-stage telescopic boom in a fully contracted state, and FIG. 3B is a side sectional view.

[Explanation of symbols]

 10 Multi-stage Telescopic Boom 11 First Boom (Outer Boom) 12 Second Boom (Outermost Inner Boom) 13 Third Boom (Inner Inner Boom) 14 Telescopic Cylinder 14a Cylinder Tube 14b Cylinder Rod 19 Roller

Claims (1)

[Scope of utility model registration request] 1. An outta boom, at least one inner boom telescopically inserted into the outta boom, and an expansion cylinder including a cylinder rod and a cylinder tube for expanding and contracting the outer boom and the inner boom. A multi-stage telescopic boom configured, wherein the telescopic cylinder is provided in an innermost inner boom of the inner boom, an outer end of the cylinder rod is pivotally attached to the outer tab, and the cylinder rod of the cylinder tube. The side is pivotally attached to the outermost inner boom in the inner boom, and rollers provided for rolling the inner surface of the innermost inner boom are provided on the left and right of the end portion of the cylinder tube opposite to the cylinder rod side. A multi-stage telescopic boom characterized by having.