Metal working – Method of mechanical manufacture – Assembling or joining
Patent
1989-08-14
1990-11-27
Lawrence, Evan
Metal working
Method of mechanical manufacture
Assembling or joining
29430, 295274, 118320, 118630, 118DIG11, 198373, 427 33, 427425, B05D 104, B05D 140, B23P 1100
Patent
active
049725696
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a method for rotatingly tranferring a hollow cylindrical article while maintaining its outer surface without any contact and an apparatus for practicing the method, and more particularly to a method for coating a hollow cylindrical article and an apparatus therefor which are advantageously applied to spray coating , jet washing or drying an electrophotographic photocondutor drum or a belt, or the like.
BACKGROUND ART
Electrostatic spray coating a cylindrical article such as, for example, a drum has been conventionally carried out by rotating drums one by one while holding them vertical, as disclosed in Japanese Patent Application Lain-Open publication No. 61672/1987.
Unfortunately, with such conventional coating, when spraying the liquid under conditions evenly forming droplets on to the drum to a degree sufficient to form a smooth film, the droplets flow down in the axial direction of the drum, resulting in the thickness of the film in the axial direction of the drum being non-constant. Also, rotation of the drums while holding them horizontal, in addition to that while holding them vertical, when electrostatic spray coating the drums one by one, results in a potential gradient which increases at the end of the drum, leading to an increase in the amount of liquid applied to the end, resulting in the thickness of the film formed on the drum being uneven. In order to avoid such a problem, it is required to arrange dummy drums on both sides of the drum to be coated. However, this substantially reduces the efficienty in coating the liquid on the drum. Furthermore, coating the drums one by one requires a drum holding and rotating mechanism for each drum, leading to not only an increase in cost but also to a failure in coating the drum symmetrically about its center in its axial direction, so causig a deterioration of the uniform spray coating on the drum. Also, this causes the drum holding and rotating mechanism to be coated likewise, resulting in a failure in the stable operation of the mechanism.
Moreover, in spray coating, it is desirable to spray liquid from a spray head continuously. Intermittent spraying of the liquid causes the liquid to dry in the spray head, leading to a failure in coating because the film formed by dried spray in the spray head is partially dissolved during a subsequent coating operation, producing foreign matter, thus, continuous coating is desired. However, conventional continuous coating leads to wastage of the liquid, resulting in an increase in cost.
SUMMARY OF THE INVENTION
The present invention has been made in view of the foregoing disadvantage.
Accordingly, it is an object of the present invention to provide a method for rotatingly transferring a hollow cylindrical article which is capable of being advantageously applied to coating or surface treating the article, and an apparatus for practicing such a method.
In the present invention a flange which is formed at its central portion with a hole is fitted to each of the two ends of a hollow cylindrical workpiece and a shaft is inserted through the hole in the flange. Then, the shaft is horizontally supported and rotated by means of a pair of vertically movable rotating rollers arranged at least two positions at each of the two ends of the shaft in such a way that they are spaced from each other by an interval equal to or greater than the length of one workpiece. The shaft is configured to cause the workpiece to be rotated coaxially in relation to the hole in the flange and is formed at that portion thereof against which each of the rotating rollers abuts into a circular shape sufficient in section to allow it to pass the hole of the flange. A pusher is arranged to transfer the workpiece on the shaft. Also, a plurality of flanged workpieces are successively inserted through the hole in the flange from one end of the shaft horizontally supported and rotated about its axis by means of the rotating rollers to join the workpieces together through both their ends in succession. Subseq
REFERENCES:
patent: 3157549 (1964-11-01), Morain
patent: 3743124 (1973-07-01), Jarvis
patent: 3859118 (1975-01-01), Snyder
patent: 3904346 (1975-09-01), Shaw et al.
Aoki Motohisa
Nakayama Ryuuji
Taguti Jiro
Umehara Tadashi
Lawrence Evan
Mitsubishi Kasei Corporation
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