Conveyors: power-driven – With means to facilitate working – treating – or inspecting... – Conveyor lowers the load to at least one of a plurality of...
Reexamination Certificate
2001-01-03
2003-12-09
Bidwell, James R. (Department: 3651)
Conveyors: power-driven
With means to facilitate working, treating, or inspecting...
Conveyor lowers the load to at least one of a plurality of...
Reexamination Certificate
active
06659262
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a conveyance apparatus which allows a workpiece supported by a conveyor to pass through a plurality of treating processes while changing its position, and more particularly to a conveyance apparatus which is suitable for a surface treatment line such as a car body painting line in vehicle manufacture. Further, the present invention relates to a conveyance path connecting a pretreatment process and a drying process, used, for example, for painting parts of a vehicle.
2. Description of the Prior Art
In a painting line for a vehicle, there are many treating processes such as pretreatment, electrodeposition, washing, painting, and drying and a workpiece is transferred among these treating processes by a conveyor. When painting of a comparatively large body of, for example, a four-wheel car is required by dipping, as shown in
FIG. 17A
, a workpiece W which has been transferred on a floor conveyor FC located on a floor is transferred to an overhead conveyor HC for hanging support. The overhead conveyor HC is enabled to move up and down in a vertical manner relative to the pretreatment and electrodeposition line. In such a condition, the workpiece W is moved vertically for dipping treatment while passing above pretreatment and electrodeposition baths and the like and then transferred again to the floor conveyor FC.
Also, in the case of electrodeposition, to obtain fine painting quality, it is known that the workpiece is rotated in an electrodeposition paint bath to change its position to a successive variety of positions (e.g. see Japanese Patent Publication No. Hei 6-104920 and Japanese Unexamined Patent Publication No. Hei 2-111481).
On the other hand, when painting of a comparatively small body of a two-wheel vehicle is required, as shown in
FIG. 17B
, it is possible to perform all painting processes using the overhead conveyor HC. Accordingly, it is not necessary to transfer the body in the middle of the painting line as with the four-wheeled vehicle. However, as far as the dipping treatment is concerned, the vertical operation is conducted in the same manner as shown above.
In the following description, a workpiece position of a type in which the workpiece is mounted and supported on a floor conveyor is called a floor conveyor position, a workpiece position of a type in which the workpiece is hung and supported is called an overhead conveyor position, and a workpiece position of a type in which the workpiece is substantially supported in a level plane at the side of the conveyor is called a side conveyor position. Further, rotation in a plane parallel to and perpendicular to the direction of travel is called vertical rotation, while rotation in a plane at right angles to the direction of travel is called horizontal rotation.
Also, for example, in the manufacture of a fuel tank, body frame or the like as parts for a motorcycle, when the tank or the frame which undergoes electrodeposition painting and the tank or frame which does not undergo electrodeposition painting are transferred on a common line, as shown in
FIG. 23
, a diverging point is provided in a line at the upstream side of an electrodeposition bath and a line A is used for the workpiece being painted, whereas a by-pass line B is used for the workpiece not being painted and these lines join in the junction at the downstream side of the electrodeposition bath.
Further, in the case of, for example, painting parts or the like of a vehicle, as shown in
FIG. 27
, for example, after a workpiece W conveyed by means of a carrier G along a workpiece conveyance path H has been immersed in an electrodeposition bath (not shown) at a pretreatment process A, the workpiece W after being removed from the electrodeposition bath is transferred to a drying process C to dry a paint film. At this time, in order to prevent hot air from the drying process C from entering the pretreatment process A, a hot air isolating zone B is generally provided between the pretreatment process A and the drying process C. The hot air isolating zone B is shortened to save a space by having an equipment formed in such a construction that, a workpeice conveying path H of the hot air isolating zone B slants, and a workpiece conveying path H of the drying process C is located at a higher position, thereby making it difficult for the hot air from the drying process C to enter the pretreatment process A.
SUMMARY OF THE INVENTION
In a process wherein the workpiece position must be changed to the floor conveyor position and the overhead conveyor position, if the workpiece has to be transferred from one conveyor to another whenever the workpiece position is changed, loss of time is caused. It is therefore desired not to transfer the workpiece while being conveyed at least in one continuous process even though the workpiece position is changed.
Further, in a method such as a dipping treatment wherein a conveyance line is continuously changed vertically, the proportion of time not suitable for dipping but required only for moving the workpiece in and out of a bath becomes large relative to the substantial dipping time of the workpiece. Accordingly, it is also desired to improve this loss of time. Also, in the case of the overhead conveyor, there is some possibility that the painting quality deteriorates when dust or the like falling from the overhead conveyor adheres to the workpiece. It is therefore desired to realize a conveyance method which keeps such falling substances from adhering to the workpiece. It is therefore a first object of the present invention to solve the above-mentioned disadvantages.
Also, if the above-mentioned by-pass line B is installed, there are disadvantages that the equipment construction including the conveyance apparatus is large in size, and the equipment cost is high, and conveying control becomes complicated.
It is therefore a second object of the present invention to solve the above-mentioned disadvantages.
Furthermore, the hot air isolating zone B having the slanting conveying path as mentioned above is still too long, therefore, it is preferable to further shorten the zone B.
It is therefore a third object of the present invention to minimize the distance between a pretreatment process and a drying process and to reduce the equipment space further, in a conveyance apparatus in which difference in height is provided for a workpiece conveyance path for the pretreatment process and a workpiece conveyance path for the drying process.
To solve the above-noted disadvantages, according to the first invention, a conveyance apparatus has a conveyor for supporting a workpiece and is adapted to allow the workpiece to pass through a plurality of treating processes while changing a workpiece position, wherein a position control mechanism for changing the workpiece position is provided so that the workpiece position required for each treating process can be continuously changed without transfer of the workpiece.
According to the present invention, the workpiece is conveyed to a plurality of treating processes which require different workpiece positions while being supported by the same conveyor and the position control mechanism is provided to allow the workpiece to be changed to the most suitable workpiece position for each process. Thus, it is no longer necessary to transfer the workpiece to another type of conveyor for each process and continuous conveyance is possible. It is therefore possible to reduce the number of transfer processes that have been required for the conventional conveyance apparatus and improve the efficiency for conveyance of the workpiece among the plurality of processes.
This position control mechanism can be arranged to either control the workpiece position to provide a floor conveyor position in which the workpiece is supported above the conveyor and an overhead conveyor position in which the workpiece is hung and supported below the conveyor; or to allow the workpiece to be supported substantially in a level plane on the side of t
Furusawa Shunichi
Nishida Hidenobu
Bidwell James R.
Honda Giken Kogyo Kabushiki Kaisha
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