Traversing hoists – Methods
Reexamination Certificate
1999-12-16
2001-10-30
Brahan, Thomas J. (Department: 3652)
Traversing hoists
Methods
C212S276000
Reexamination Certificate
active
06308844
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for handling an equipment inside a building by a crane installed outside.
Of late years, a large crane is more frequently used in a construction project and maintenance project of, for example, power station or chemical plant as a means for shortening the project schedule and making up for a lack of skilled labors and field labors. Particularly in a maintenance project, it is frequently needed to replace a component part of a product installed there.
In carrying out a replacement work, advanced operation technique to the order of millimeter is required of a large crane to avoid possible trouble such as interference with existing facilities. Such replacement work is disclosed in Japanese Laid-Open Patent Publication No. Hei 8-435777 (1996).
Generally, in removing a product out of a place, there occurs a phenomenon that, as the load of the product transfers from the installation surface of the product to the large crane, the boom of the large crane moves downward and the boom top shifts from the vertical line above the product. This means that a tension is applied from the wire to the product installed on the ground in the forward direction of the boom.
As the product is set free horizontally at the moment when being lifted off from the installation surface (as soon as the product is fully lifted up), it is swung forward by the afore-mentioned tension.
In carrying a product into a place and installing it, on the other hand, as the load of the product is transferred from the large crane to the contact surface (installation position), the boom of the large crane moves backward from the vertical line above the product and accordingly a horizontal load is applied from the wire to the product in the backward direction of the boom.
Conventionally, installation using a large crane was mostly applied to a new construction project. Because a product which required lifting operation in the course of the construction was lifted from an outdoor temporary storage yard, cares were taken so that interference with adjacent objects would be avoided even if the product swung upon the lift-off.
Beside, when carrying a product into a place, it was sufficient to rely only upon the crane operator's skill to achieve required accuracy of the carriage because the product was to be placed down on a foundation structure which was constructed in consideration of some impact.
In a maintenance project, on the other hand, if no measures are taken when removing a product out of a limited place in a building where existing facilities stand in the neighborhood of the product, it is possible that the product swings as soon as it is lifted up and may collide against the existing facilities.
Besides, when a replacement product is carried into a place and the products is adjusted to its installation position or matched to the existing mating piping, controlling the moving range of the replacement product is necessary for fine adjustment and how the afore-mentioned horizontal load from the wire can be eliminated is an important point.
As a means to solve these problems, one of the methods could be to shift the boom in the opposite direction prior to lifting up a product. According to Japanese Laid-Open Patent Publication No. Sho 64-38397 (1989), by inputting data acquired though a load test in an arithmetic unit prior to actual lifting operation, it is said to be possible to quantitatively predict at time of actual lift-off how much the boom needs to be shifted beforehand in the opposite direction for a given load. A similar method is also known according to Japanese Laid-Open Patent Publication No. Hei 1-167199 (1989).
According to Japanese Laid-Open Patent Publication No. Hei 9-79826 (1997), it is said to be possible to detect a change in the crane working radius caused by bowed deformation of the crane jib due to load, using a tachymeter employed for land survey and multiple reflecting mirrors mounted on the jib.
According to Japanese Laid-Open Patent Publication No. Hei 1-256497 (1989), by detecting a change in the boom length and derricking angle caused by deflection of the boom during actual lifting operation and correcting the derricking motion of the boom automatically, it is said to be possible to prevent swinging of a product upon lift-off. Similar methods are also known according to Japanese Laid-Open Patent Publication No. Hei 1-256496 (1989), and Laid-Open Utility Model Publication Nos. Hei 5-46882 (1993) and Hei 63-4989 (1988).
SUMMARY OF THE INVENTION
With regard to the method described in Japanese Laid-Open Patent Publication No. Sho 64-38397 (1989) and others, where the shift of the boom in the opposite direction is obtained automatically at time of the lifting operation by registering the load data obtained from a prior test, it is difficult to completely eliminate the swing during the lifting operation because external obstructive factors (e.g. weather condition such as wind) during the actual lifting operation cannot be taken into account.
With regard to the method described in Japanese Laid-Open Patent Publication No. Hei 9-79826 (1997), where a change in the crane jib radius is detected using a tachymeter and reflecting mirrors, method for relating the obtained change to the crane operation is not clearly described.
Moreover, because the measuring point is established on each crane jib, resulting in more frequent measurement and higher data volume, it is difficult to feed back the data to the crane operation in a short period of time.
With regard to the method described in Japanese Laid-Open Patent Publication No. Hei 1-256497 (1989), where a change in the boom length and derricking angle is detected, it is not easy to take measurement because specific detector is required for each crane. Moreover, method for preventing collision against existing structures in the neighborhood caused by the swing of the product upon lift-off (the product which has been fully lifted up from the ground) is not clearly described.
Therefore, an object of the present invention is to provide accurate control in handling an equipment inside a building in vertical direction, using a crane installed outside.
Fundamental requirement of the means for achieving the object of the present invention is a method for handling an equipment inside a building by a crane installed outside; said method being employed when leading a wire hanging from the boom of a crane installed outside into said building through an opening provided on said building, and lifting up or down an equipment inside said building by said wire; said method including a process for moving said boom up or down toward a correct position for lifting said equipment vertically in the course of transferring dead weight of said equipment between said wire and a structure inside said building; said method allowing to accurately handle an equipment inside a building in vertical direction even if the inside of the building cannot be observed from the operator's cage of the crane.
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patent: 5907111 (1999-05-01), Josten et al.
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Hasegawa Hiroshi
Miura Jun
Miyahara Ryohei
Okada Hisako
Ushiroda Kouichi
Antonelli Terry Stout & Kraus LLP
Brahan Thomas J.
Hitachi , Ltd.
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