JPH0117995B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a lifting load detection device for a working vehicle.

(Prior Art) For example, in an aerial work vehicle a as shown in FIG. It is pivotally mounted so that it can be raised and lowered, and the raising and lowering angle is controlled by the raising and lowering cylinder e. Further, the boom d has a built-in telescopic cylinder (not shown), and is configured in a multi-stage telescopic type whose length is variable. Furthermore, a workbench g is attached to the tip of the boom d via a connecting member f. A hoisting device h is provided on the upper part of the connecting member f, and raises and lowers the load by feeding out and winding a wire j having a hook i at its tip.

In the above-mentioned aerial work vehicle a, the permissible load that can be lifted by the hoisting device h is limited according to the undulation angle and extension/contraction length of the boom d in order to prevent it from overturning. Therefore, when a hoisting device for hoisting a load at the tip of a boom is installed in such an aerial work vehicle, it is necessary to measure this hoisting load. Conventionally, electric means such as a strain meter have been used to measure this lifting load.

(Problems to be Solved by the Invention) As mentioned above, if electrical means are used as a means to measure the lifting load by the hoisting device, there is a problem not only in ensuring insulation but also in reliability in terms of accuracy. The problem was that it lacked sex.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a hoisting device 1 as shown in FIGS. 1 and 2.
A drum shaft 3 is connected to an output shaft 2a of a hoisting motor 2, and a drum 4 is screwed onto the outer periphery of the drum shaft 3 by a threaded portion 5. This threaded part 5 is formed between the drum shaft 3 and the drum 4, and for example, the threaded part 5 is formed between the drum shaft 3 and the drum 4.
A female thread 4c is provided on the inner periphery of the sleeve 4b, which is supported so that mutual rotation is restrained by a straight spline 4a and mutual axial movement is freely supported, and a female thread 4c is provided on the outer periphery of the drum shaft 3. It consists of a male thread 3a. A gap 6 between the drum shaft 3 and the drum 4, including the threaded portion 5, is sealed with fluid. Also, the drum 4 has a hoisting wire 7
is wound.

(Function) If configured by the above-described means, the threaded portion 5 is right-handed and the hoisting wire 7 is connected to the drum 4.
is wound counterclockwise as shown in Fig. 2, and when a load is suspended from the hook 8 at the tip of the hoisting wire 7, a counterclockwise couple is generated on the drum 4 as shown in Fig. 2. do. On the other hand, the threaded portion 5 has a left-handed internal thread 4c, which generates a force in the right direction in FIG. By measuring the pressure of this fluid, the magnitude of the load suspended from the hook 8 can be detected.

(Example) Examples of the present invention will be described in detail below.

The hoisting motor 2 of the hoisting device 1 according to the present invention, which is taken out from the tip of the boom d of the aerial work vehicle a, uses a forward-reverse rotation hydraulic motor with a speed reducer, but other electric motors may be used. The hoisting motor 2 is fixed to a bracket 9, and the output shaft 2a and the base end of the drum shaft 3 are connected by a key 10.

Also, the tip of the drum shaft 3 is attached to the bracket 9.
It is supported by a ball bearing 11a in a holder 11 which is integrally fixed with the holder 11. The drum shaft 3 has a communication hole 3b that communicates the gap 6 with the tip of the drum shaft 3, and is bent in the radial direction near the tip of the drum shaft 3 to form an opening 3c on the circumferential surface of the drum shaft 3. ing. On the other hand, holder 11
A groove 11b is provided on the inner circumference corresponding to the opening 3c, and a pressure outlet 11c is provided in a part of this groove 11b.
is open. Note that O-rings 11d for preventing leakage are fitted on both sides of the groove 11b. A pressure gauge 13 is connected from the pressure outlet 11c via a communication pipe 12.
The pressure of the hydraulic oil filled in the cavity 6 is measured. Furthermore, the communication pipe 12 is extended along the boom d explained in FIG.
Instead, a known pressure switch may be connected to control the lifting angle and extension/contraction length of the boom d explained in FIG. 4.

In order to allow the drum 4 and the drum shaft 3 to freely rotate relative to each other, ball bearings 4d, 4d are fitted at two locations on the base end side and the distal end side of the drum shaft 3.

In order to prevent oil leakage on both sides of the gap 6 in the axial direction, O-rings 4e and 4e are fitted between the drum shaft 3 and the drum 4 and between the drum shaft 3 and the sleeve 4b. A packing 4g is fitted between the sleeve 4b and the sleeve 4b. Further, a plug 6a for removing air from the gap 6 is screwed into a part of the drum 4.

The base end of the hoisting wire 7 wound around the drum 4 is fixed to a wire stopper 4h provided integrally with the drum 4.

Note that the O-ring 4e or 11 in the cavity 6
A replenishment line 14 as shown in FIG. 3 is provided to replenish any leakage of hydraulic oil from d or packing 4g, or leakage of hydraulic oil when the self-sealing coupling of the communication pipe 12 is attached or detached. The supply pipe line 14 is connected to the drain pipe line of the hoisting motor 2 and the communication pipe 12.
A check valve 14a is interposed between the
Hydraulic oil inside the hoisting motor 2 is supplied to the gap 6 via a communication pipe 12. In addition, in Fig. 3, 15 is a self-sealing coupling;
16 is a hydraulic switching valve for the hoisting motor 2.

Further, in the above-mentioned embodiment, the sleeve 4b was interposed between the drum 4 and the drum shaft 3, but this sleeve 4b is eliminated, and the internal thread of the threaded part 5 is provided directly on the inner circumference of the drum 4, so that the drum 4 can be It may be supported so as to be movable in the axial direction with respect to the drum shaft 3, for example, by a roller bearing.

Furthermore, the hoisting device 1 according to the present invention may be used not only for the above-mentioned aerial work vehicle, but also for other types of crane vehicles, and may also be used for vehicles other than these specially equipped vehicles. good.

(Effects of the Invention) As described above, this invention attaches the drum to the drum shaft by screwing it together, seals the fluid in the gap formed between them, and converts the couple acting between the drum shaft and the drum into fluid pressure. Since this method is used to detect lifting loads by taking out a It can be used in areas where it is necessary, and can have remarkable effects.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a longitudinal side view, FIG. 2 is a cross-sectional view taken along the - line, FIG. 3 is a pipe diagram, and FIG. 4 is an embodiment of the present invention. FIG. 2 is a side view of an effective aerial work vehicle. 1... Hoisting device, 2... Hoisting motor, 2a...
Output shaft, 3...Drum shaft, 4...Drum,
4b...Sleeve, 5...Screwed portion, 6...Gap,
7...Hoisting wire.

Claims (1)

[Claims] 1. In a work vehicle having a hoisting device, the hoisting device has a drum shaft connected to the output shaft of a hoisting motor, and the drum shaft and the drum around which the hoisting wire is wound are attached via a threaded part. , characterized in that a fluid is sealed in a gap between the drum shaft and the drum including the threaded portion, and the lifting load applied to the drum is detected by measuring the pressure generated in the fluid. Lifting load detection device for work vehicles.