JPH0659387U - Work platform lifting device for aerial work platforms - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a workbench lifting device for an aerial work vehicle, which allows a large lifting amount of the workbench relative to the stroke of the cylinder. [Structure] Holding member 7 provided on vertical post member 6a
The cylinder 11 and the fixed sprocket 14 are attached to c, and the cylinder sprocket 12 is attached to the telescopic rod 11a of this cylinder 11. Further, a moving sprocket 15 is attached to the other end of the first chain 13 whose one end is fixed to the holding member and is wound around the cylinder sprocket 12 and the fixed sprocket 14, and the first sprocket 15 is wound around the moving sprocket 15. 2 chains 16
Has one end fixed to the holding member 7c and the other end connected to the workbench 7. As a result, it is possible to obtain a lift amount of the work table 7 which is four times as large as the stroke of the cylinder 11.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a work platform lifting device capable of lifting and lowering a work platform in an aerial work vehicle having a work platform attached to the tip of a boom.

[0002]

[Prior art]

 An aerial work vehicle is configured with a work platform on which a worker can ride at the tip of a boom that can be undulated, extended and retracted, and swiveled, and a vertical post is provided at the tip of the boom by a leveling mechanism to raise and lower the boom. It is held and attached so that it is always vertical regardless of, and the workbench is attached horizontally to this vertical post. In such an aerial work vehicle, the work platform on which the worker is mounted is moved to a predetermined work position (for example, near a utility pole) by raising, retracting, retracting, or turning the boom. To do. Raising, retracting, turning, etc. of the boom are performed by operating the drive levers for operating each operation by operating each operation lever.

When the workbench is moved to a predetermined work position to perform work, it may be necessary to move the workbench in the vertical direction depending on the content of the work. Conventionally, when the workbench is moved vertically, it has been performed by performing a combination of hoisting and extending and retracting operations of the boom. In this case, for example, in order to raise the work platform only in the vertical direction, it is necessary to simultaneously operate the two operating levers for raising and lowering and extending and retracting the boom to elevate and extend the boom. , When the workbench is located near a power pole, if the boom extension operation precedes the boom elevating operation, the workbench may come into contact with the power pole. Has a problem that requires skill.

Therefore, in order to solve such a problem, the present applicant attaches to the tip of the boom as shown in FIG. 3 so that only the workbench can be moved up and down without operating the boom. We proposed a workbench lifting / lowering device that lifts and lowers the workbench with respect to the vertical posts provided. In this lifting / lowering device, a workbench 27 is attached so as to be vertically movable with respect to a vertical post 26a, and a cylinder 31 provided on the vertical post 26a and a cylinder sprocket 32 attached to a cylinder rod 31a and It is composed of a chain 33 wound around a fixed sprocket 34. Since both ends of the chain 33 are fixed to the workbench 27 and the vertical post 26a, the workbench 27 can be moved up and down by the expansion and contraction operation of the cylinder 31. Since the expansion / contraction operation of the cylinder 31 can be performed by operating a single operation lever (not shown), even a worker unskilled in the operation can easily move the work table up and down.

[0005]

[Problems to be solved by the device]

 However, with the lifting / lowering device configured as described above, since the worktable lift amount was only 2 L when the cylinder stroke was L, the lift amount was insufficient depending on the work content, and the boom was again used. There was a problem that it was necessary to perform undulation and expansion / contraction operation. It is possible to use a cylinder with a long stroke as a means for solving this problem, but a cylinder with a long stroke increases the weight. Since this cylinder is installed near the vertical post attached to the tip of the boom or near the workbench, when the weight increases, the load at the tip of the boom increases, and when the boom is raised and extended, the vehicle body is not supported. There was a problem that the operating range of the boom (safe work range) where work could be performed without stability was narrowed.

The present invention has been made in view of the above problems, and obtains a workbench lifting device for an aerial work vehicle capable of significantly increasing the lifting amount of the workbench relative to the stroke of the cylinder. Is intended.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, in an aerial work vehicle equipped with a workbench lifting device according to the present invention, a cylinder and a second sprocket are attached to a holding member provided on one of the vertical post member and the workbench. , The first sprocket is attached to the telescopic rod of this cylinder. Also, a third sprocket is attached to the other end of the first chain, one end of which is fixed to the holding member and which is hung around the first sprocket and the second sprocket, and hung around the third sprocket. The second chain has one end fixed to the holding member and the other end fixed to the other of the vertical post member and the workbench.

[0008]

[Action]

 In such a workbench lifting device, when raising and lowering only the workbench vertically without performing boom hoisting, expansion and contraction, etc., a workbench larger than the stroke of the cylinder used as the drive means is used. The amount of elevation can be obtained.

[0009]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, an example of an aerial work vehicle having a workbench lifting device according to the present invention is shown in FIG. This aerial work vehicle has a swivel base 2 that can swivel on a vehicle body 1, and an extendable and retractable boom 3 is attached to the swivel base 2 so as to be capable of hoisting. The telescopic boom 3 is composed of a telescopically (nestedly) telescopically extensible base boom 3a, an intermediate boom 3b and a tip boom 3c. The base boom 3a is pivotally supported on the swivel base 2 via a support shaft 2a. It can be undulated. The telescopic boom 3 is telescopically operated by a telescopic cylinder (not shown) provided inside, and is hoisted and raised by an undulating cylinder 4 provided between the swivel base 2 and the base end boom 3a. .

A support member 6 pivotally supported by a pin 3d and swingably moved up and down is attached to the tip of the tip boom 3c, and the support member 6 is attached so as to be constantly vertical through the leveling mechanisms 5a and 5b. Has been. The support member 6 has a vertical post 6a, and a pair of brackets 7a and 7b of a workbench 7 are rotatably attached to the vertical post 6a. Further, a workbench 7 is attached to the other end of the bracket so as to elevate itself through an elevating device.

In the aerial work vehicle constructed as described above, the work table 7 is moved to a predetermined work position by turning, elevating or retracting the boom 3 to perform work. At this time, depending on the content of the work, it may be necessary to move the work position vertically from the position where the work was being performed. Therefore, the workbench lifting device as shown in FIG. 1 raises and lowers the workbench.

In the workbench lifting device shown in FIG. 1, the expansion and contraction operation of the cylinder is transmitted by a chain and a sprocket to raise and lower the workbench. A workbench-side lifting guide 7d is attached to the workbench 7, and a holding member 7c that is slidably fitted to the lifting guide 7d is provided between the brackets 7a and 7b. As a result, the work table 7 is supported so as to be vertically movable and horizontally rotatable with respect to the vertical post 6a. A hydraulic cylinder 11 for expanding and contracting by hydraulic pressure is provided as a driving means for moving the work table 7 up and down. The operation of the hydraulic cylinder 11 is performed by supplying a hydraulic pressure to the hydraulic cylinder 11 by operating a single operating lever (not shown) provided inside the workbench 7.

The hydraulic cylinder 11 is attached to the holding member 7c so that the cylinder rod 11a side is located downward, and a cylinder sprocket (first sprocket) 12 is rotatably attached to the tip of the cylinder rod 11a. ing. A fixed sprocket (second sprocket) 14 is rotatably attached to the holding member 7c. One end of each sprocket 12, 14 is fixed to the holding member 7c and the other end is rotatably attached. The first chain 13 to which the moving sprocket (third sprocket) 15 is attached is wound around. The moving sprocket 15 is configured to be movable up and down with respect to the holding member 7c. One end of the sprocket 15 is fixed to the holding member 7c and the other end is attached to the workbench 7. The second chain 16 connected to the chain connecting member 17 is wound around.

In the lifting device configured as described above, the work table 7 is lifted and lowered by operating the operation lever. The case of raising the work table 7 will be described below. When the operator operates the operation lever, the cylinder rod 11a extends by the stroke L as shown by the chain line. At this time, the first chain 13 hung around the cylinder sprocket 12 has one end fixed to the holding member 7c and further hung around the fixed sprocket 14, so that the moving sprocket 15 attached to the other end. Is operated to pull up (upward in the direction of the arrow). The moving amount of the moving sprocket 15 is twice the moving amount (2L) of the cylinder stroke L.

When the movable sprocket 15 moves upward, the work table 7 connected to the other end of the second chain 16 wound around the movable sprocket 15 ascends. At this time, since one end of the second chain 16 is fixed to the holding member 7c, the amount of movement of the work table 7 is twice the amount of movement of the movable sprocket 15. Therefore, according to such a lifting / lowering device for the workbench, the workbench 7 can be lifted 4 L with respect to the stroke L of the cylinder 11. As a result, it is not necessary to use a cylinder with a long stroke, and the amount of lifting and lowering of the workbench 7 can be made large. Therefore, work efficiency is improved without reducing the safe work range due to an increase in the load at the tip of the boom. Can be achieved.

In the above embodiment, the case where the workbench is raised has been described, but if the cylinder is contracted, the workbench is lowered due to the weight of the workbench. Therefore, if the worktable has been lifted at the same amount as before, and if you want to lower the workbench as well, keep the workbench at the intermediate position of the cylinder stroke and then perform boom extension / contraction operations. The workbench may be moved to a predetermined work position. As a result, since it is possible to move up and down from the work position, it is possible to improve work efficiency.

Further, although the above embodiment shows the case where the holding member is attached to the vertical post, the present invention is not limited to this, and the holding member is attached to the workbench and the cylinder is attached to the holding member. Alternatively, sprockets or the like may be attached. In this case, the configuration is symmetrical with the above embodiment, such as by mounting the cylinder rod upward.

[0018]

[Effect of device]

 As described above, in the work platform lifting device for an aerial work vehicle according to the present invention, the cylinder and the fixed sprocket are attached to the holding member provided on the vertical post member, and the cylinder sprocket is attached to the telescopic rod of this cylinder. . A moving sprocket is attached to the other end of the first chain, one end of which is fixed to the holding member and which is hung around the cylinder sprocket and the fixed sprocket, and the second chain which is hung around this moving sprocket is , One end is fixed to the holding member and the other end is connected to the worktable. This makes it possible to obtain a four-fold increase / decrease of the work table with respect to the stroke of the cylinder.

[Brief description of drawings]

FIG. 1 is a detailed side view of a workbench periphery of an aerial work vehicle having a workbench lifting device according to the present invention.

FIG. 2 is a side view showing an aerial work vehicle having a workbench lifting device according to the present invention.

FIG. 3 is a side view showing in detail around the workbench of an aerial work vehicle having a workbench lifting device according to a conventional example.

[Explanation of symbols]

 2 swivel base 3 telescopic boom 6 support member 6a vertical post 7 workbench 11 cylinder 12 cylinder sprocket (first sprocket) 13 first chain 14 fixed sprocket (second sprocket) 15 movable sprocket (third sprocket) 16 second chain 17 Chain connecting member

Claims (1)

[Scope of utility model registration request] 1. A boom in which an operation such as ups and downs is freely arranged on a vehicle body, and a vertical post member which is attached to the tip of the boom via a leveling mechanism so as to be always held vertically. A workbench attached to a vertical post member so as to be vertically movable, a holding member provided on one of the vertical post member and the workbench, a cylinder attached to the holding member, and an extension / contraction of the cylinder. A first sprocket rotatably attached to a rod, a second sprocket rotatably attached to the holding member, and one end fixed to the holding member and hung on the first sprocket and the second sprocket. A first chain, a third sprocket rotatably attached to the other end side of the first chain, and one end of the third chain to the holding member. A work platform lift of an aerial work vehicle, comprising: a second chain fixedly attached to the third sprocket and wound around the third sprocket and the other end of which is fixed to the other end of the work platform. apparatus.