Conveyors: power-driven – Conveyor system for moving a specific load as a separate unit – System includes a load supported by a conveyor portion which...
Reexamination Certificate
2002-10-18
2004-10-12
Hess, Douglas (Department: 3651)
Conveyors: power-driven
Conveyor system for moving a specific load as a separate unit
System includes a load supported by a conveyor portion which...
C198S678100, C198S680000, C198S687000
Reexamination Certificate
active
06802413
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to hanging conveyance equipment and a learning system for learning operating conditions of the equipment in advance.
PRIOR ART
Japanese Unexamined Patent Publication No. H11-349280 discloses conventional hanging conveyance equipment. This equipment includes a carriage fitted with a work hand, which can move vertically and be positioned horizontally two-dimensionally with respect to it. The work hand can hold a work and move vertically with the work hanging from it. The carriage can run along a path, below which a number of work supports are arranged. The work hand can load and unload each of the work supports.
In this type of hanging conveyance equipment, the carriage can be stopped accurately in the stop position set above each of the work supports. However, if the work supports are installed or fixed at different degrees of accuracy, the work hand of the carriage in each of the stop positions is displaced with respect to the associated work support laterally and/or angularly around a vertical axis. When a work is lowered onto each the work supports, and when the work on each of the work supports is lifted, the position of the work hand may need to be highly precise. In this case, as disclosed in the foregoing publication, amounts of horizontal two-dimensional positioning for the work hand can be preset for each of the work supports. When the work hand is lowered from the carriage in the stop position for the work support, the work hand can be positioned horizontally two-dimensionally with the associated amounts of positioning.
Specifically, in Japanese Unexamined Patent Publication No. H11-349280, with the carriage in the stop position above each of the work supports, the amounts of horizontal two-dimensional displacement of the work hand with respect to the work support are detected. On the basis of the detected amounts, amounts of positioning for the work hand are set for the work support. Accordingly, both when the work on each of the work supports is lifted to be conveyed from it, and when a work is lowered to be supplied to each the work supports, the work hand is positioned with respect to the carriage only on the basis of the associated amounts of positioning.
In this type of hanging conveyance equipment, the work hand is hung from the carriage by belts that can be extended and taken up. It is possible to lift the work on each of the work supports by lowering the empty work hand to a position where the hand can hold the work. The lowered empty hand may be in a horizontal position. It is possible to lower a work with the work hand by lowering the hand to a position where the load can be unloaded. The lowered work hand holding the work may be inclined because of various factors, such as a shift of the center of gravity of the work, different amounts of extension of the belts, and low producing accuracy of the head of the work. The heads of all works may be inclined uniformly and low in producing accuracy accordingly. The inclination of the work hand leads to horizontal two-dimensional displacement of the hand with respect to the work support. It is consequently impossible to lower the work accurately to a predetermined position on the work support only by positioning the work hand with the same amounts when the work is lifted and when the work is lowered.
SUMMARY OF THE INVENTION
The object of the present invention is to provide hanging conveyance equipment that can load and unload works safely and accurately by solving the foregoing conventional problem.
According to a first aspect of the present invention, hanging conveyance equipment is provided, which comprises a carriage, a number of work supports and a work hand. The carriage travels along a horizontal travelling path, which has stop positions arranged along it. Each of the work supports is fixed below one of the stop positions. An amount of work-lifting positioning and an amount of work-lowering positioning are set for each of the work supports. The work hand can hold a work hanging from it. The work hand is supported by the carriage in such a manner that the work hand can be positioned horizontally two-dimensionally with respect to the carriage. The work hand can vertically move with respect to the carriage to load a work onto or unload a work from each of the work supports. When the work hand is lowered from the carriage in each of the stop positions to lift a work from the associated work support, the work hand is positioned horizontally two-dimensionally in accordance with the amount of work-lifting positioning for the support. When the work hand is lowered from the carriage in each of the stop positions to lower a work onto the associated work support, the work hand is positioned horizontally two-dimensionally in accordance with the amount of work-lowering positioning for the support.
The work supports may be fixed at low or different degrees of accuracy with respect to the horizontal travelling path, along which the carriage travels. In such a case, when the work hand is lowered to a position over each of the work supports to load or unload the support, the hand might otherwise be displaced horizontally two-dimensionally with respect to a fixed position on the support. The displacement would make it impossible to place a work in the fixed position on the work support, or to normally lift a work supported in the fixed position.
As stated already, an amount of work-lifting positioning and an amount of work-lowering positioning are set for each of the work supports. When the work hand is lowered from the carriage in each of the stop positions to lift a work from the associated work support, the work hand is positioned horizontally two-dimensionally in accordance with the amount of work-lifting positioning for the support. When the work hand is lowered from the carriage in each of the stop positions to lower a work onto the associated work support, the work hand is positioned horizontally two-dimensionally in accordance with the amount of work-lowering positioning for the support. There may be a case where the empty work hand is lowered to a position over one of the work supports to lift a work from the support, and where the work hand holding a work is lowered to a horizontally two-dimensionally different position over the same support. Even in this case, the work hand can be lowered safely and securely or reliably.
After the empty work hand is lowered, it can hold a work and then be lifted without problems. When the work hand holding a work is lowered so that the work can be placed on each of the work supports, the hand and work may be inclined due to various factors as stated earlier. The inclination would otherwise displace the work horizontally two-dimensionally with respect to the work support. However, the work hand is positioned in accordance with the associated amount of work-lowering positioning so that the inclined work can be placed accurately in the fixed position on the work support.
The amount of work-lowering positioning for each of the work supports may be the associated amount of work-lifting positioning corrected with an amount of correction equivalent to the error between the position of the work hand holding a work and lowered to a predetermined height over the work support and the position of the hand lowered to the height without holding a work. This obviates the need to find both the amount of work-lifting positioning and the amount of work-lowering positioning for each of the work supports by a learning process or the like. Consequently, the time and labor required for the learning process etc. are reduced, and it is easy to operate the conveyance equipment.
The work hand may be positioned with respect to the carriage in parallel with the horizontal travelling path, laterally at right angles to the path and angularly around a vertical axis. In practice, however, if the carriage can stop accurately in the stop positions, the work hand does not need to be positioned in parallel with the travelling path. In other words, practically, the
Daifuku Co. Ltd.
Goodwin & Procter LLP
Hess Douglas
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