JP2567985Y2 - Telescopic mast extension mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telescopic mechanism of a telescopic mast for raising and lowering a work floor of an aerial work vehicle.

[0002]

2. Description of the Related Art An aerial work vehicle used for an interior construction work of a building or the like is constructed by mounting a telescopic mast for raising and lowering on a movable traveling vehicle. The elevating telescopic mast is vertically mounted on an inner mast member which is vertically mounted on a chassis (base) of a traveling vehicle, and is mounted around an outer periphery of the inner mast member so as to be vertically movable with respect to the inner mast member. It is configured to be telescopically expandable and contractable from the outer mast member. At the lower end of the outer mast member, a work floor for boarding a worker is horizontally mounted. For this reason, by extending and retracting the elevating telescopic mast, the worker on the work floor can move to an arbitrary high place, and can easily perform a work of attaching a plate material to a high ceiling portion. it can.

[0003] By the way, as shown in FIG. 3 (A), the conventional telescopic drive for raising and lowering the telescoping mast is performed by a hydraulic drive using a single-acting hydraulic cylinder 33 built in the mast 32 and a self-weight reduction. The system was often adopted. That is, the bottom end of the hydraulic cylinder 33 is attached to the lower end of the inner mast member 32a, and the tip of the piston rod 33a of the hydraulic cylinder 33 is attached to the inside of the upper end of the outer mast member 32b. Then, the hydraulic cylinder 3
The hydraulic cylinder 33 is extended by supplying hydraulic oil into an oil chamber 33b formed on the bottom side of 3 to extend the elevating telescopic mast 32. On the other hand, by gradually discharging the hydraulic oil from inside the oil chamber 33b,
The hydraulic cylinder 33 is reduced in its own weight according to the weight of the outer mast member 32b and the work floor, and the retractable mast 32 is reduced. By reducing the weight of the hydraulic cylinder 33, the hydraulic supply device 34 does not need to be operated when the elevating mast 32 is reduced, so that energy saving operation is possible.

[0004]

However, in such a hydraulic drive system, there is a problem that the floor of a building may be stained by leakage of hydraulic oil. In addition, there is a problem that it is troublesome because periodic maintenance of the hydraulic oil is required. Furthermore, when the elevating mast is reduced by using the self-weight reduction of the single-acting hydraulic cylinder, the play between the mast members and the play between the end of the piston rod and the outer mast member are reduced. 3
As shown in (B), there is a possibility that the outer mast member 32b may be inclined with respect to the inner mast member 32a. In this case, both members 32a and 32b are positioned at the portions indicated by ★ in the drawing. There is also a problem that the reduction operation is not performed smoothly due to being caught.

Conventionally, in addition to the hydraulic drive system,
As shown in FIG. 4, the outer mast is wound around the sheave 45 attached to the upper end of the inner mast member 42a while the tip of the wire 44 drawn out from the electric winch 43 attached to the lower end of the inner mast member 42a. A wire-type telescopic drive system fixed to the lower end of the member 42b may be employed. In this driving method, the outer mast member 42b is pulled up by winding the wire 44 by the winch 43 to extend the elevating telescopic mast 42, and the wire 4
4, the outer mast member 42b
Is lowered by its own weight, etc.
Is to be reduced. However, in this wire-type telescopic drive system, although there is no possibility of hydraulic oil leaking, the telescopic mast 42 for raising and lowering can be used cleanly, but as in the hydraulic drive system described above, there is a possibility that the contraction operation may not be performed smoothly. There is no change in point.

The present invention has been made in view of such a problem, and makes it possible to use an elevating mast for raising and lowering cleanly and easily without worrying about leakage of hydraulic oil. It is an object of the present invention to provide a telescopic mechanism of a telescopic mast for raising and lowering which enables the telescopic mast for raising and lowering to be smoothly extended and retracted.

[0007]

In order to achieve the above object, a telescopic mechanism according to the present invention comprises a sprocket which is rotatably mounted on a lower end and an upper end of an inner mast member, and a chain is attached to these sprockets endlessly. Wrapped around. A part of a portion of the chain stretched between the two sprockets is connected to a base end of the outer mast member via a connecting member. The sprocket attached to the lower end of the inner mast member is driven by an electric motor.

[0008]

In such a telescopic mechanism, the outer mast member is moved relative to the inner mast member by operating the electric motor to drive the sprocket at the lower end and rotating the chain in a direction to raise the connecting member. The elevating mast can be extended by the chain and lifted by the chain. Further, by rotating the chain in a direction to raise the connecting member, the outer mast member is pulled down by the chain. For this reason, even if there is some catch between both mast members, the elevating telescopic mast can be smoothly reduced. Since the hydraulic mechanism does not use the hydraulic oil, the telescopic mast for raising and lowering can be used cleanly without fear of leakage of the hydraulic oil.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows an aerial work vehicle 10 equipped with a safety device for a lifting device according to the present invention. The aerial work vehicle 10 is a traveling carriage 11 that can travel freely.
A telescopic lifting mast (elevating device: hereinafter, referred to as an elevating mast) 12 is provided in front of the upper part. The lifting mast 12 includes an inner mast member 12 a vertically attached to the traveling vehicle 11 and an inner mast member 1 a.
An outer mast member 12b movably arranged up and down on the outer side of the outer mast 2a is configured to be telescopically extensible. On the lower rear side of the outer mast member 12b,
A work floor 13 is attached, and an operator M can board the work floor 13. A gart 14 surrounding the space above the work floor 13 is attached to the upper part of the outer mast member 12b, and the worker M who has boarded the work floor 13 enters the work g It is not necessary to fall from 13.

Next, the elevating mast 12 is extended and retracted.
The expansion mechanism according to the present invention will be described with reference to FIG.
The extension mechanism 20 includes a lower sprocket 25d rotatably attached to a lower end of the inner mast member 12a,
An upper sprocket 25u rotatably attached to the upper end of the inner mast member 12a, and a chain 2 endlessly wound around these sprockets 25d and 25u.
6 are provided. A connecting member 26a is attached to a part of a portion of the chain 26 that is stretched behind the two sprockets 25d and 25u.
The connecting member 26a is connected to the outer mast member 1
2b is fixed inside the base end.

The telescopic mechanism 20 has an electric motor 27 for rotating and driving the lower sprocket 25d, and an electromagnetic brake 28 integrally attached to the electric motor 27. The electric motor 27 is attached to a lower end portion of the inner mast member 12a via a bracket 27a, and power is transmitted from an output shaft thereof to a lower sprocket 25d via a speed reducing means 29. Therefore, by rotating the electric motor 27 forward and backward, the lower sprocket 25d is also driven forward and reverse. The electromagnetic brake 28 has a built-in solenoid (not shown). When the solenoid is not excited (when the electric motor 27 is not operated), the electromagnetic brake 28 locks and the outer mast member 1
The so-called self-propelled rotation of the electric motor 27 is prevented by the weight of 2b itself and the weight of the worker M (the weight mounted on the work floor 13). When the solenoid is excited (when the electric motor 27 operates), the lock operation is released and the rotation of the electric motor 27 is permitted.

According to the telescopic mechanism 20 configured as described above, when the electric motor 27 is operated to rotate the chain 26 in the direction in which the connecting member 26a rises, the outer mast member 12b is pulled up by the chain 26. ,
It moves up and down with respect to the inner mast member 12a. Thus, the elevating mast 12 can be extended, and the worker M can move to an arbitrary height together with the work floor 13.

On the other hand, if the chain 26 is rotated in the direction in which the connecting member 26a descends, the outer mast member 12b
Is lowered by the chain 26 and moves downward with respect to the inner mast member 12a. At this time, there is a possibility that the outer mast member 12b is inclined with respect to the inner mast member 12a due to a loose fit between the two mast members 12a and 12b, so that the two mast members 12a and 12b may be caught. However, in this telescopic mechanism 20,
Since the outer mast member 12b is forcibly pulled down by the chain 26, the outer mast member 12b can be smoothly moved down even if there is such a catch. In this manner, the lifting mast 12 can be smoothly reduced in size, and the worker M can move down from a height with the work floor 13.

Since the hydraulic mechanism is not used in the telescopic mechanism 20, there is no need to worry about leakage of hydraulic oil.
2, that is, the aerial work vehicle 10 can be used cleanly. Also, since no maintenance of the hydraulic oil is required, handling is easy.

[0015]

As described above, in the telescopic mechanism of the present invention, not only the outer mast member is raised but also lowered with respect to the inner mast member by the endless chain. For this reason, if this telescopic mechanism is used,
At the time of the contraction operation of the elevating telescopic mast, the telescopic operation can be smoothly performed even if there is a catch between the two mast members. Further, since the hydraulic mechanism is not used in the present expansion and contraction mechanism, there is no need to worry about hydraulic oil leakage and maintenance of the hydraulic oil. Therefore, if this telescopic mechanism is used,
The telescopic mast for raising and lowering can be used cleanly and easily.

[Brief description of the drawings]

FIG. 1 is a side view of an aerial work vehicle equipped with a telescopic mechanism of a telescopic mast for lifting according to the present invention.

FIG. 2 is a side view of the extension mechanism.

FIG. 3A is a schematic view of a conventional telescopic mechanism,
(B) is a side sectional view of a conventional elevating telescopic mast.

FIG. 4 is a schematic view of a conventional telescopic mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Aerial work vehicle 12 Telescopic lifting mast 12a Inner mast member 12b Outer mast member 13 Work floor 20 Telescopic mechanism 25d, 25u Sprocket 26 Chain 26a Connecting member 27 Electric motor 28 Electromagnetic brake 29 Deceleration means

Claims (1)

(57) [Scope of request for utility model registration] 1. An inner mast member vertically mounted on a base and an outer mast member mounted on the outside of the inner mast member so as to be vertically movable with respect to the inner mast member. A vertically movable telescoping mechanism for a vertically movable telescopic mast that is configured to freely move up and down a work floor or the like attached to the outer mast member, wherein the lower and upper ends of the inner mast member are rotatable. Two sprockets to be attached, a chain wound around these sprockets endlessly, and a connecting member for connecting a part of a part of the chain stretched between the two sprockets to a base end of the outer mast member. A sprocket attached to a lower end of the inner mast member of the two sprockets; Stretch mechanism of the elevating telescoping mast, characterized in that it is composed of the sprocket and a motor for rotating.