JP2000264593A - Assisting arm for works - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive assisting arm for works easy to make locking and releasing of a spherical joint and capable of widening the degree of freedom of the facing of a working device. SOLUTION: This assisting arm 40 for works is fitted with a fixture 41 to be attached to the forefront of a sub-boom 19, a universal joint 43 connected with the fixture 41, a drive device 45 coupled with the universal joint 43, and a grasping tool 47 mounted on the drive device 45. The fixture 41 may be attached in a plurality of directions in position avoiding a sheave 27 installed at the forefront of the sub-boom 23, and in mounting in any direction, the grasping tool 47 is held in a position not interferring with the sheave 27 or a rope W extending down from it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work assist arm, and more particularly, to the replacement of an insulator, a switch, and the like on a utility pole.
In addition, the present invention relates to a work assist arm used for gripping an electric wire.

[0002]

2. Description of the Related Art When exchanging insulators, switches and the like on a utility pole, an aerial work vehicle as shown in FIG. 9 may be used. The aerial work vehicle 1 has a telescoping boom 9 that can move up and down on the vehicle body 3, and a worktable 17 on which a worker M can be mounted at a tip end of the telescoping boom 9. Move to a higher position.

In order to perform insulator replacement work using this aerial work vehicle 1, two workers board the work table 17,
One worker M temporarily holds the electric wire using the holder, and the other worker M replaces the insulator. For this reason, at least two workers are required, thus reducing the overall work efficiency.

[0004] Therefore, there has been proposed a work assist arm for temporarily holding an electric wire instead of an operator for temporarily holding an electric wire. As shown in FIG. 10, the work assisting arm 100 is attached to the inside of the worktable 17 as necessary, and includes a plurality of arm members 103 connected via a spherical joint 101 and the arm member 103. And a gripping device 105 swingably provided at the distal end portion 103. The gripping device 105 is configured to be opened and closed by a built-in hydraulic actuator.

Further, as shown in FIG.
A work assist arm 109 is provided at the tip of a sub-boom 107 which is provided on a vertical post 13 provided at the tip of the sub boom 107 so as to be able to move up and down and pivot. As shown in FIG. 12, the work assisting arm 109 has a rectangular cylindrical arm main body 111 and a gripping device 113 disposed at a distal end of the arm main body 111. A spherical joint 117 having a spherical member 115 is provided between the arm body 11 and the holding device 113, and the holding means 113 is configured to be swingable in all directions with respect to the arm body 111.

The opening and closing of the gripping device 113 is performed by a hydraulic cylinder (not shown), and the hydraulic cylinder is driven by a driving source provided in the arm body 111. The drive source is the control box 119 and the power unit 12
1 and a battery 123, and the power unit 1
Reference numeral 21 includes an electric motor, a hydraulic pump, and a tank. The operating oil in the tank is supplied to the hydraulic cylinder and the lock release cylinder of the gripping device 113 through the nylon hose 125 by receiving power supply from the battery 123.

[0007]

However, FIG.
The work assist arm 100 shown in FIG. 1 has only a single function of holding only, so that the work content is limited and the usability is poor. In addition, a spherical joint 101 that opens and closes a brake by hydraulic pressure is used as a joint of the work assist arm 100, and the opening and closing of the brake is performed by a battery-driven hydraulic pressure generating device 126. Charging is required, increasing costs.

Further, a work assist arm 109 shown in FIG.
In addition to the above problems, the work assist arm 109
Can be connected to the sub-boom 107 only in one direction, so that the orientation of the gripping device 109 can be changed only within a predetermined range, and it is possible for a certain work but not applicable to other works. Problems arise.

The present invention has been made in view of such a problem, and can be applied to operations other than gripping. The mechanism for locking and unlocking the spherical joint is easy, and the degree of freedom of the orientation of the working device is increased. It is an object of the present invention to provide a large and inexpensive work assist arm.

[0010]

In order to solve the above-mentioned problems, a work assisting arm according to the present invention includes a lifting device (for example, a telescopic boom in the embodiment) provided on a base (for example, a vehicle body 3 in the embodiment). 9) A workbench or a lifting / lowering device on which a worker can be mounted is provided at the tip of the sub-boom so as to be able to move up and down, and is disposed at the tip of a sub-boom having a rotatable sheave at the tip. The work assist arm includes fixing means (for example, the fixing tool 41 in the embodiment) that can be mounted on the sub-boom, a working device (for example, the gripping tool 47 in the embodiment) for performing a predetermined operation, and a working device attached to the fixing means. And a working device holding means (for example, the universal joint 43 in the embodiment) for holding the fixing means, and the fixing means can be attached in a plurality of directions at positions avoiding the sheave. Preferably, the working device is held in a position that does not interfere with the sheave and the rope extending downward from the sheave.

The fixing means can be attached in a plurality of directions at positions avoiding the sheave, and the working device is connected to the fixing means via the working device holding means. The orientation of the working device can be changed. Also, regardless of the direction in which the fixing means is attached, the working device is held at a position where it does not interfere with the sheave and the rope extending downward from the sheave. Can be moved up and down to a desired position. For this reason, the work device enables gripping of wires and the like, and the work performed by two workers can be performed by one worker, thereby improving work efficiency.

The working device includes a driving device (for example, the hydraulic motor 96 in the embodiment) for generating a driving force, and tool means (for example, a hydraulic motor 96 in the embodiment) that can be mounted on the driving device and operate by receiving the driving force to perform predetermined work. It is preferable that the working device holding means has a universal joint that swings the drive device in all directions.

The drive unit for generating the driving force of the working unit and the tool unit are separated from each other, and the tool unit can be mounted on the drive unit, so that a tool according to the work content can be used, thereby improving the usability. be able to. Further, when the working device holding means has a universal joint for swinging the driving device in all directions, the direction of the tool means mounted on the driving device can be adjusted, and the work can be performed efficiently. be able to.

The universal joint has an operation lock means (for example, the pressing member 73 and the spring 75 in the embodiment) for locking the operation, and an operation lock release means for releasing the operation lock of the operation lock means (for example, a single unit in the embodiment). It is preferable to have a dynamic cylinder 71). By operating the operation locking means, the universal joint can be locked and the direction of the tool means connected to the universal joint can be fixed in a desired direction. By activating the operation lock releasing means to release the operation lock of the operation lock means, the direction of the tool means can be adjusted in a predetermined direction.

It is preferable that the operation lock releasing means is a manual hydraulic pump for manually supplying pressure oil to the operation locking means and releasing the operation lock of the operation locking means. As a method of releasing the operation lock of the operation lock means, there is a method of using a hydraulic pressure generating device that operates by receiving power supply from a battery.However, using a manual hydraulic pump eliminates the need for power supply, thereby reducing economical efficiency. improves.

The fixing means has a plurality of insertion holes (for example, the first insertion hole in the embodiment) which can be inserted through the sub-boom from a plurality of directions.
It is preferable to have the insertion hole 55 and the second insertion hole 56), to select one of the insertion holes, mount the fixing means on the sub-boom, and mount the working device in a predetermined direction. Since the fixing means can be attached to the sub boom from multiple directions,
The degree of freedom of the orientation of the working device connected thereto is increased, the orientation of the working device can be adjusted according to the work content, and usability and work efficiency can be improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIGS. This embodiment shows an aspect of an aerial work vehicle having a telescoping boom that can swing freely on a vehicle body. This aerial work vehicle 1 is, as shown in FIG.
An outrigger jack 5 is provided on the left and right sides of the front and rear sides of the vehicle body 3 so as to protrude to the side of the vehicle body 3 and to stably support the vehicle body 3 by grounding its lower end. At the front center of the vehicle body 3, there is provided a swivel 7 which projects upward and is capable of swiveling. A telescopic boom 9 is provided above the revolving base 7 so as to be vertically swingable.

An up-and-down cylinder 11 is pivotally connected between the bottom of the telescopic boom 9 and the bottom of the swivel 7 so that the up-and-down cylinder 11 moves up and down when the up-and-down cylinder 11 expands and contracts. ing. At the tip of the telescopic boom 9, there is provided a vertical post 13 that always extends in the vertical direction regardless of the angle of the telescopic boom 9. A horizontal arm 15 protruding in the horizontal direction is provided on a side portion of the vertical post 13, and a work table 17 on which a worker M can be mounted is provided at a distal end of the horizontal arm 15.

A sub-boom 19 is provided above the vertical post 13. As shown in FIGS. 2 and 3, the sub-boom 19 includes a sub-boom holding portion 21 provided at the tip of the vertical post 13 so as to be pivotable and undulating.
A sub-boom main body 23, which is slidably provided in the axial direction with respect to the sub-boom holding section 21, and a work assist arm 40 attached to the distal end of the sub-boom main body 23.
And The winch 2 is attached to the sub boom holding section 21.
The winch 25 is provided with a rope W wound thereon.

A sub-boom head 29 having a rotatable sheave 27 is provided at the tip of the sub-boom main body 23 so as to be freely inserted and removed. A head through hole (not shown) penetrating in the horizontal direction is provided at an end of the sub boom head 29 on the winch side, and a boom through hole (not shown) penetrating in the horizontal direction also at the tip of the sub boom main body 23. ) Is provided,
When the sub-boom head 29 is inserted into the tip of the sub-boom main body 23, the boom through-hole and the head through-hole communicate with each other to form a communication hole (not shown).
By inserting the bolt 59 into this communication hole, it is possible to prevent the sub boom head 29 from coming out of the sub boom main body 23. A rope W extended from the winch 25 is wrapped around the sheave 27, and a hook 3
1 is provided. By suspending a device such as a switch on the hook 31 and winding up the winch 25, the device can be moved to a desired height.

A work assist arm 40 is provided on the left side (the lower side in FIG. 2) of the sub-boom head 29 shown in FIG. The work assist arm 40 has a fixture 41, a universal joint 43, a driving device 45, and a gripping tool 47. FIG. 4A is a plan view of the tip of the sub-boom 19, and FIG. 4B is a front view of the tip of the sub-boom 19. The fixing tool 41 is disposed in a state of being fitted to the tip of the sub-boom main body 23 and to the right of the sub-boom head 29, as shown in FIG.

The fixing tool 41 is composed of a pair of rectangular plates 4 provided with a predetermined gap in the width direction of the sub-boom main body 23.
9 and two connecting rods 51 and two connecting plates 53 for connecting the plates 49 to each other. Two connecting rods 5
1, 51 connect the upper and lower right edge portions of the pair of plates 49, and
A plurality of connecting plates 53 connect the left and right edges of the pair of plates 49. The gap between the pair of plates 49 is
The gaps between the pair of connecting rods 51 and between the pair of connecting plates 53 are slightly larger than the height dimension of the sub-boom main body 23. Also, the connecting rod 51 in the longitudinal direction of the sub-boom main body 23
The gap between the sub-boom main body 23 and the connecting plate 53 is arranged to be larger than the height dimension of the sub-boom main body 23.

For this reason, a first insertion hole 55 for inserting the sub-boom main body 23 in the horizontal direction and a second insertion hole 56 for inserting the sub-boom main body 23 in a direction perpendicular to the first insertion hole 55 are formed in the fixture 41. Have been. First insertion hole 55
When the sub-boom main body 23 is inserted into the sub-boom main body 23, the upper surface of the sub-boom main body 23 comes into contact with the lower surfaces of the connecting rods 51 and the connecting plate 53 provided on the upper part of the plate 49, and the fixing tool 41 is held by the sub-boom main body 23. . When the sub-boom main body 23 is inserted through the second insertion hole 56 shown in FIG. 5, the upper surface of the sub-boom main body 23 and the lower surfaces of the two connecting rods 51 abut, and the fixing tool 41 is held by the sub-boom main body 23. You.

As shown in FIG. 4 (b), the pair of plates 49 are provided with two through holes 57, 58 at the left central portion and the central upper portion of each plate 49. After the sub-boom main body 23 is inserted through the first insertion hole 55 of the fixing tool 41, the sub-boom head 29 is connected to the sub-boom main body 23.
Communication hole (not shown) formed when inserted at the tip of
With the through hole 57 and the communication hole with the bolt 5.
By inserting the nut 9 into the tip of the bolt 59 and screwing the nut 61 to the tip of the bolt 59, the sub boom head 29 and the fixing tool 41 can be prevented from coming off from the tip of the sub boom main body 23.

Further, as shown in FIG. 5, after the sub-boom main body 23 is inserted into the second insertion hole 56 of the fixture 41 so that the universal joint 43 faces downward, the sub-boom head 29 is When inserted into the distal end, the through hole 58 communicates with the communication hole (not shown), and a bolt 59 is inserted into the communicating through hole 58 and the communication hole, and a nut is screwed into the through hole 58 so as to face the sub boom head 29. It is possible to prevent the fixing tool 41 with the changed shape from coming off from the distal end portion of the sub-boom main body 23. For this reason, since the fixing tool 41 can be attached to the tip of the sub-boom main body 23 while changing its direction, it is possible to adjust the direction of the gripping tool 47 shown in FIG.

A connecting arm 63 projecting to the left side (downward in FIG. 4) of the sub-boom is provided at the front end of a plate 49 disposed on the left side of the front end of the sub-boom 19 shown in FIG. A universal joint 43 is provided at the distal end of the universal joint 43 so as to extend in parallel with the extending direction of the sub boom 19. FIG. 6 is a cross-sectional view of a portion corresponding to the arrow IV-IV in FIG. 4A. As shown in FIG. 6, the universal joint 43 has a housing 65, a spherical member 67, and a single-acting cylinder 71. ing.

The housing 65 includes a base housing 65a fixed to the connection arm 63 and a base housing 65a.
a inside housing 65b screwed into the inside of the proximal housing from the inside tip to the middle
And a tip housing 65c attached to the outside of the tip of the inner housing 65b by screwing. A spherical spherical member 67 is provided inside the distal end of the distal end housing 65c.
Are slidably held. A pressing member 73 for pressing the spherical member is provided inside the inner housing 65b so as to be slidable in the left and right directions in the inner housing 65b.
A spring 75 is interposed between the bottom of the pressing member 73 and the bottom of the inner housing 65b. The spring 75 constantly presses the pressing member 73 toward the spherical member 67. For this reason, the sliding of the spherical member 67 can be fixed (locked).

The pressing member 73 is connected to the rod-side distal end of a single-acting cylinder 71 provided at the bottom of the base housing 65a. For this reason, when the single-acting cylinder 71 is contracted, the pressing member 73 moves toward the single-acting cylinder 71 against the spring 75, and the operation lock of the spherical member 67 can be released.

The single-acting cylinder 71 is connected to a hydraulic circuit 77 shown in FIG. The hydraulic circuit 77 includes a supply line 79 for supplying hydraulic oil to the single-acting cylinder 71, a return line 81 for returning hydraulic oil in the single-acting cylinder 71, and a supply line 79.
And a relief line 83 for keeping the internal pressure constant. The supply pipe 79 is provided with a strainer 87 and a manual hydraulic pump 89 for removing dust in the working oil stored in the oil tank 85 from the upstream side. The manual hydraulic pump 89 is provided so as to be hung in the work table 17 shown in FIG. 2, and has an operation lever 91 operated by the worker M.
When the operating lever 91 is operated, the operating oil in the oil tank 85 shown in FIG.
1, the single-acting cylinder 71 is contracted, the pressing of the pressing member 73 is released, and the operation lock of the spherical member 67 is released.

One end of the return line 81 is a single-acting cylinder 7.
It is connected to a supply pipe 79 between the first hydraulic pump 89 and the manual hydraulic pump 89, and the other end is opened into the oil tank 85. The return line 81 is provided with a stop valve 93. When the stop valve 93 is opened, the hydraulic oil in the single-acting cylinder 71
And presses the pressing member 73 by the spring 75 to the spherical member 6.
7 to lock the operation of the spherical member 67. That is, the spherical member 67 can be locked or unlocked by operating the manual hydraulic pump 89 and the stop valve 93.

A square shaft 94 is connected to the spherical member 67 shown in FIG. 6, and a driving device 45 is connected to the tip of the shaft 94. The driving device 45 has a hydraulic motor 96 inside a housing 95, and the hydraulic motor 9
A tool attachment / detachment adapter 98 for detachably attaching a tool to the drive shaft 97 at the distal end of the actuator 6 and transmitting the driving force of the hydraulic motor 96 is provided.

The gripping tool 47 shown in FIG. The gripping tool 47 is configured so that the tip thereof opens and closes by the driving force of the driving device 45. It should be noted that other tools can be attached to the drive device 45 in addition to the gripping tool 47 in accordance with the work content.

Next, the operation of replacing the insulator provided on the utility pole D using the work assisting arm 40 of the present invention will be described.
First, with the telescopic boom 9 stored on the vehicle body 3 shown in FIG. 8, the aerial work vehicle 1 is moved below the utility pole D around the work site, the outrigger jack 5 is extended, and the lower end thereof is grounded. To stably support the vehicle body 3. And
The worker M rides on the work table 17 and operates an operation device (not shown) provided in the work table 17 to turn the turntable 7, raise and lower the telescopic boom 9, and extend the telescopic boom 9. The table 17 is moved near the insulator 33 installed on the upper part of the telephone pole D.

Then, the operator M operates the operating lever 91 of the manual hydraulic pump 89 shown in FIG.
The operation oil is supplied to the inside, and the operation lock of the spherical member 67 is released so that the orientation of the gripping tool 47 can be swung in all directions. The worker M holds the hot stick 35 or the like in his hand,
After adjusting the inclination of the tip of the gripping tool 47 using this, the stop valve 93 is opened to discharge the hydraulic oil in the single-acting cylinder 71, the operation of the spherical member 67 is locked, and Fix the orientation.

Then, the sub-boom 19 shown in FIG. 8 is moved up and down and extended. The extension operation of the sub-boom 19 is performed by hooking the hook 31 provided at the tip of the rope W wound around the winch 25 on the ring 37 provided at the base of the sub-boom main body 23 shown in FIG. It is performed by If the sub-boom main body 23 projects from the sub-boom holding portion 21 to a desired length by winding the rope W, the operation of the winch 25 is stopped,
The sub-boom main body 23 is fixed to the sub-boom holding section 21. The fixing is performed by inserting the pin 39 from the sub-boom holding portion 21 into the sub-boom main body 23.

When the gripping tool 47 shown in FIG. 8 is moved near the insulator 33 to be replaced, the driving device 45 is operated to open the tip of the gripping tool 47, and the upper part of the utility pole D is placed in the opened gripping tool 47. After adjusting the position of the gripping tool 47 with the raising and lowering of the sub boom 19, expansion and contraction, turning, and a hot stick so that the arm bar 34 attached in the horizontal direction comes to
The driving device 45 is operated, and the gripping tool 47 grips the arm bar 34. Then, the worker M uses the working rod to move the insulator 3
The nut 36 screwed into the lower part of the bolt 38 that penetrates through the 3 and projects downward from the insulator 33 is removed, and the insulator 33 is removed from the arm 34. Note that the elevation angle of the sub-boom 19 is limited, but the sub-boom 19 is raised and the insulator 33 is raised.
If the insulator 33 can be removed from the arm bar 34 without using the work bar, the sub boom 19 can be used.

Then, the new insulator 33 is gripped by the working rod, and the insulator 33 is mounted on the arm 34, and then the insulator 33 is gripped by the gripping tool 47. The operation of gripping the insulator 33 by the gripping tool 47 has been described above and will not be described. And
In order to fix the replaced insulator 33 to the utility pole D, an operator M screws a nut 36 to a bolt 38 projecting from a lower portion of the insulator 33 using a working rod. At this time, since the insulator 33 is gripped by the gripping tool 47, the worker M can concentrate on the work of attaching the nut 36 to the bolt 38. Thus, the work assist arm 40 allows the insulator 33 to be used.
, The insulator 33 can be replaced by one worker M.

In the above-described embodiment, the work assist arm 40
Although the replacement operation of the insulator 33 by the above has been described, the invention is not limited to this, and the work assist arm 40 can be used for gripping the electric wire or replacing the switch.

[0039]

As described above, according to the work assist arm of the present invention, the fixing means can be attached in a plurality of directions at positions avoiding the sheave, and the fixing means can be attached to the fixing means via the working device holding means. Since the working device is connected, the direction of the working device can be changed depending on the mounting direction of the fixing means. Also, regardless of the direction in which the fixing means is attached, the working device is held at a position that does not interfere with the sheave and the rope extending downward from the sheave. Thus, the work performed by two workers can be performed by one person, and the work efficiency can be improved.

Further, the working device has a driving device for generating a driving force, and tool means which can be mounted on the driving device and operate by receiving the driving force to perform predetermined work. In the case of having a universal joint for swinging the device omnidirectionally, a driving device and a tool device are separately provided, and the tool device can be mounted on the driving device, so that a tool according to the work content can be provided. Can be used and usability is improved. In addition, by providing the drive unit so as to be swingable in all directions by the universal joint, the direction of the tool means mounted on the drive unit can be adjusted, and the work can be performed efficiently.

Further, when the universal joint has an operation locking means for locking the operation and an operation lock releasing means for releasing the operation lock, the operation locking means is operated to lock the universal joint so that the tool means can be locked. The direction of the tool means can be adjusted to a predetermined direction by operating the operation lock release means to release the operation lock of the operation lock means.

When the operation lock releasing means is a manual hydraulic pump, the operation lock release means is operated by a battery compared with the prior art in which the operation lock is released using a hydraulic pressure generating device which operates by receiving power supply from the battery. Efficiency is improved because power supply is unnecessary.

Further, the fixing means has a plurality of insertion holes which can be inserted into the sub-boom from a plurality of directions. One of the insertion holes is selected, the fixing means is mounted on the sub-boom, and the working device is oriented in a predetermined direction. In the case where the work device is mounted, the degree of freedom of the direction of the work device can be increased, the direction of the work device can be adjusted according to the work content, and usability and work efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a front view of an aerial work vehicle equipped with a work assist arm according to an embodiment of the present invention.

FIG. 2 is a plan view of a work table having a work assist arm according to one embodiment of the present invention.

FIG. 3 is a front view of a work table having a work assist arm according to one embodiment of the present invention.

FIGS. 4A and 4B show a part of the work assisting arm in one embodiment of the present invention, wherein FIG. 4A is a plan view of the work assisting arm, and FIG. 4B is a front view of the work assisting arm. .

FIG. 5 is a front view showing a state in which the mounting direction of the work assisting arm is changed according to the embodiment of the present invention.

FIG. 6 is a sectional view of a work assist arm according to the embodiment of the present invention.

FIG. 7 shows a hydraulic circuit connected to the work assist arm in one embodiment of the present invention.

FIG. 8 is a view for explaining the operation when the insulator is replaced by using the work assisting arm according to the embodiment of the present invention.

FIG. 9 is a diagram for explaining a conventional technique.

FIG. 10 is a diagram for explaining a conventional technique.

FIG. 11 is a diagram for explaining a conventional technique.

FIG. 12 is a diagram for explaining a conventional technique.

[Explanation of symbols]

 Reference Signs List 3 vehicle body (base) 9 telescopic boom (elevating device) 17 work table 19 sub boom 27 sheave 40 work assist arm 41 fixing tool (fixing means) 43 universal joint (work device holding means) 45 drive device 47 gripping tool (work device, Tool means) 55 First insertion hole (insertion hole) 56 Second insertion hole (insertion hole) 71 Single acting cylinder (operation lock release means) 73 Pressing member (operation lock means) 75 Spring (operation lock means) 89 Manual hydraulic pump M worker W rope

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shinsuke Ito 4-8 Onaridori, Kita-ku, Nagoya-shi Inside Chubu Electric Power Company (72) Inventor Kenichi Hyodo 4-8 Onaridori, Kita-ku, Nagoya-shi Chubu Electric Power Company Inside the North Sales Office (72) Inventor Takashi Mori 1015-2 Yamashita, Ryoji, Ryoke, Ageo City, Saitama Prefecture Inside Aichi Corporation Ageo Works Co., Ltd. Aichi Corporation Ageo Works (72) Inventor Fumio Watanabe 1152 Yamashita, Ryoke, Oji, Saitama Prefecture F-term (reference) 3F333 AA08 AB04 AC13 BA12 BB11 DA02 DA05 DB07 DB10 FG07 FH01

Claims (5)

[Claims] A work table on which a worker can ride is provided at a tip of a lifting device provided on a base, and is provided at the tip of the work table or the lifting device so as to be able to move up and down. In a sub-boom having a movable sheave, a work auxiliary arm disposed at a tip end of the sub-boom, a fixing means attachable to the sub-boom, a working device for performing a predetermined operation, and an attachment to the fixing means And a working device holding means for holding the working device, wherein the fixing means can be attached in a plurality of directions at positions avoiding the sheave, and the working device is attached in any direction. The work assist arm is held at a position not to interfere with the sheave and a rope extending downward from the sheave. 2. The working device includes a driving device for generating a driving force, and tool means that can be mounted on the driving device and perform a predetermined operation by receiving the driving force from the driving device and operating. The work assist arm according to claim 1, wherein the work device holding means includes a universal joint that swings the drive device in all directions. 3. The work assist arm according to claim 2, further comprising an operation lock unit that locks the operation of the universal joint, and an operation lock release unit that releases the operation lock of the operation lock unit. 4. The work assistance according to claim 3, wherein said operation lock releasing means is a manual hydraulic pump for manually supplying pressure oil to said operation locking means to release the operation lock of said operation locking means. arm. 5. The fixing means has a plurality of insertion holes which can be inserted through the sub-boom from a plurality of directions, and selects one of the insertion holes to mount the fixing means on the sub-boom. The work assist arm according to any one of claims 1 to 4, wherein the work device is attached in a predetermined direction.