JPH0645985U - Telescopic mast telescopic mechanism for lifting - Google Patents

Abstract

(57) [Summary] [Purpose] The expansion / contraction mechanism for the lifting / lowering telescopic mast shall be such that the lifting / lowering telescopic mast can be used cleanly and easily without the risk of hydraulic oil leakage, and there is play between the mast members. Shall also be able to smoothly expand and contract. [Structure] The expansion / contraction mechanism 20 includes an inner mast member 12
Sprockets 25d and 25u are rotatably attached to the lower end and the upper end of a, respectively, and a chain 26 is wound around these sprockets endlessly. In addition,
A part of the portion of the chain 26 stretched between both sprockets is connected to the base end of the outer mast member 12b via a connecting member 26a. Then, the sprocket 25 attached to the lower end of the inner mast member 12a
d is driven by the electric motor 27.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a telescopic mast extension mechanism for elevating a work floor of an aerial work vehicle.

[0002]

[Prior art]

 An aerial work vehicle used for building interior work, etc., has an elevating telescopic mast mounted on a traveling carriage that can travel freely. This elevating telescopic mast is mounted vertically on an undercarriage (base) of a traveling trolley, and on the outer periphery of the inner mast member so as to be vertically movable relative to the inner mast member. It is composed of an outer mast member that can be telescopically expanded and contracted. At the lower end of the outer mast member, a work floor for the workers to board is horizontally installed. Therefore, by expanding and contracting the elevating telescopic mast, the worker on the work floor can move to an arbitrary height, and the work of attaching the plate material to the high ceiling part can be easily performed. it can.

By the way, as shown in FIG. 3 (A), the conventional expansion / contraction drive of a telescopic mast for lifting / lowering uses a hydraulic drive that uses an extension operation of a single-acting hydraulic cylinder 33 built in the mast 32 and reduction of its own weight. The method 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, hydraulic oil is supplied from the hydraulic pressure supply device 34 mounted on the chassis 31 into the oil chamber 33b formed on the bottom side of the hydraulic cylinder 33, so that the hydraulic cylinder 33 is extended and the vertical expansion / contraction is performed. Extend the mast 32. On the other hand, by gradually discharging the hydraulic oil from the oil chamber 33b, the weight of the outer mast member 32b and the work floor causes the hydraulic cylinder 33 to reduce its own weight, and the ascent / descent telescopic mast 32 is reduced. Since the hydraulic cylinder 33 is reduced by its own weight, it is not necessary to operate the hydraulic pressure supply device 34 when the elevating telescopic mast 32 is contracted, so that energy saving operation can be performed accordingly.

[0004]

[Problems to be solved by the device]

 However, such a hydraulic drive system has a problem that the floor surface of the building may be contaminated due to leakage of hydraulic oil. Further, there is a problem that it is troublesome because the hydraulic oil needs to be regularly maintained. Furthermore, when the telescopic mast for raising and lowering is reduced by utilizing the self-weight reduction of the single-acting hydraulic cylinder, due to the fitting play between both mast members and the mounting play between the tip of the piston rod and the outer mast member, As shown in FIG. 3 (B), 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 indicated by a star in the figure. There is also a problem that it is caught in a part and the reduction operation is not performed smoothly.

Conventionally, in addition to this hydraulic drive system, as shown in FIG. 4, the tip of the wire 44 extended from the electric winch 43 attached to the lower end portion of the inner mast member 42a is attached to the inner mast member 42a. There is also a case where a wire type telescopic drive system is adopted in which the outer mast member 42b is fixed to the lower end portion of the outer mast member 42b while being hung around the sheave 45 attached to the upper end portion thereof. In this drive system, by winding the wire 44 with the winch 43, the outer mast member 42b is pulled up, the elevating telescopic mast 42 is extended, and the wire 44 is unwound from the winch 43, so that the outer mast member 42b is removed. It is lowered by its own weight and the like, and the elevating telescopic mast 42 is contracted. However, with this wire type telescopic drive system, there is no risk of hydraulic oil leaks, etc., but the elevating telescopic mast 42 can be used cleanly, but as with the hydraulic drive system described above, the reduction operation is not performed smoothly. There is no change in that there is.

The present invention has been made in view of the above problems, and it is assumed that the telescopic mast for lifting and lowering can be used cleanly and easily without fear of hydraulic oil leakage, and further there is backlash between mast members. It is an object of the present invention to provide a telescopic mast extension / contraction mechanism that allows the elevating telescopic mast to be smoothly extended / contracted even if there is.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the expansion / contraction mechanism of the present invention comprises sprockets rotatably attached to the lower end and the upper end of the inner mast member, and an endless chain is wound around these sprockets. Part of the portion of the chain stretched between both sprockets is connected to the 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]

[Action]

 In such a telescopic mechanism, the outer mast member is pulled up by the chain with respect to the inner mast member by operating the electric motor to drive the sprocket on the lower end side and rotating the chain in the direction to raise the connecting member. Thus, the elevating telescopic mast can be extended. Further, by rotating the chain in the direction of raising the connecting member, the outer mast member is pulled down by the chain. Therefore, even if there is some catch between the mast members, the elevating telescopic mast can be smoothly reduced. Since this telescopic mechanism does not use hydraulic oil, the elevating telescopic mast can be used for the cleaner without fear of hydraulic oil leakage.

[0009]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described 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. This aerial work vehicle 10 is configured to include a retractable lift mast (lift device: hereinafter referred to as lift mast) 12 in front of an upper portion of a traveling carriage 11. The elevating mast 12 is telescopically extendable from an inner mast member 12a vertically attached to the traveling carriage 11 and an outer mast member 12b vertically arranged outside the inner mast member 12a. It is configured. A work floor 13 is attached to the lower rear side of the outer mast member 12b, and a worker M can board the work floor 13. Further, a gart 14 surrounding the space above the work floor 13 is attached to the upper part of the outer mast member 12b, and a worker M who has boarded the work floor 13 enters inside the gart 14 by It does not have to fall from the work floor 13.

Next, an expansion / contraction mechanism according to the present invention for expanding / contracting the lifting mast 12 will be described with reference to FIG. The expansion / contraction mechanism 20 includes a lower sprocket 25d rotatably attached to the 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 these sprockets 25d, 25u. And is chained endlessly and has a chain 26. A connecting member 26a is attached to a part of the portion of the chain 26 stretched to the rear side of both sprockets 25d and 25u. The connecting member 26a is fixed to the inside of the base end portion of the outer mast member 12b.

Further, the extension / contraction mechanism 20 has an electric motor 27 that rotationally drives the lower sprocket 25 d, and an electromagnetic brake 28 that is integrally attached to the electric motor 27. The electric motor 27 is attached to the lower end of the inner mast member 12a via a bracket 27a, and power is transmitted from its output shaft to the lower sprocket 25d via a speed reducing means 29. Therefore, by rotating the electric motor 27 in the normal and reverse directions, the lower sprocket 25d is also driven in the normal and reverse directions. The electromagnetic brake 28 has a solenoid (not shown) built therein, and when the solenoid is not excited (when the electric motor 27 is not operated), the electromagnetic brake 28 is locked and the weight and work of the outer mast member 12b itself is reduced. The weight of the person M (the weight loaded on the work floor 13) prevents the electric motor 27 from rotating so-called self-propelled. When the solenoid is excited (when the electric motor 27 is operating), the lock operation is released and the electric motor 27 is allowed to rotate.

According to the expanding / contracting mechanism 20 configured in this manner, the outer mast member 12 b is pulled up by the chain 26 by operating the electric motor 27 to rotate the chain 26 in the direction in which the connecting member 26 a is raised. , Moves up and down relative to the inner mast member 12a. In this way, 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, when the chain 26 is rotated in the direction in which the connecting member 26a descends, the outer mast member 12b is pulled down by the chain 26 and moves downward with respect to the inner mast member 12a. At this time, the outer mast member 12b may be inclined with respect to the inner mast member 12a due to the looseness of the fitting between the both mast members 12a and 12b, and the two mast members 12a and 12b may be caught. However, in this extension / contraction mechanism 20, the outer mast member 12b is forcibly pulled down by the chain 26, so even if there is such a catch, the outer mast member 12b can be smoothly moved downward. In this way, the lifting mast 12 can be smoothly reduced, and the worker M can descend from a high place together with the work floor 13.

Since no hydraulic oil is used in the telescopic mechanism 20, the lifting mast 12, that is, the aerial work vehicle 10 can be used cleanly without fear of hydraulic oil leakage. Further, since maintenance of the hydraulic oil is unnecessary, it is easy to handle.

[0015]

[Effect of device]

 As described above, in the telescopic mechanism of the present invention, the endless chain not only pulls up the outer mast member with respect to the inner mast member, but also lowers it. For this reason, by using the present expansion / contraction mechanism, it is possible to perform the expansion / contraction operation smoothly even when there is a catch or the like between the mast members, especially during the contraction operation of the elevating expansion / contraction mast. In addition, since this telescopic mechanism does not use hydraulic fluid, there is no need to worry about hydraulic fluid leakage or maintenance of hydraulic fluid. Therefore, the use of this telescopic mechanism makes it possible to use the telescopic mast for raising and lowering cleanly and easily.

[Brief description of drawings]

FIG. 1 is a side view of an aerial work vehicle having a telescopic mast extension / contraction mechanism according to the present invention.

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

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

FIG. 4 is a schematic view of a conventional expansion / contraction mechanism.

[Explanation of symbols]

 10 High-altitude work vehicle 12 Telescopic lifting mast 12a Inner mast member 12b Outer mast member 13 Working floor 20 Telescopic mechanism 25d, 25u Sprocket 26 Chain 26a Connecting member 27 Electric motor 28 Electromagnetic brake 29 Reduction means

Claims (1)

[Scope of utility model registration request] 1. A telescope-like expansion and contraction from an inner mast member vertically mounted on a base and an outer mast member mounted on the outer side of the inner mast member so as to be vertically movable with respect to the inner mast member. An expansion / contraction mechanism of a vertically movable telescopic mast that is freely configured to be telescopically moved to vertically move a work floor or the like attached to the outer mast member, and is rotatably attached to a lower end portion and an upper end portion of the inner mast member. Two sprockets to be attached, a chain wound around these sprockets endlessly, and a connecting member for connecting a part of the portion of the chain stretched between the two sprockets to the base end of the outer mast member. Attached to the 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.