1. Field of the Invention
The present invention relates to a vibratory barrel finishing apparatus and, more particularly, to a long-travel annular vibratory barrel type finishing apparatus for line-processing.
Vibratory barrel finishing apparatuses are broadly divisible into two types: a box-type and a circular-type. The vibratory barrel finishing apparatus of the present invention possesses the advantages inherent in both these two types of apparatus, i.e. an oval path having adaptability for long line-finishing which is an advantage peculiar to the box-type apparatus and a spiral flow of mass which is an advantage of the circular-type apparatus.
2. Description of the Prior Art
German Patents DBP1047993, DBP1036092 and U.S. Pat. No. 3,071,900, disclose vibratory finishing apparatuses in which the line of the conventional box-type vibratory barrel is extended. In this known type of apparatus, however, a huge driving means is required for effecting the driving, separation and circulation of mass, resulting in an impractically high cost of production. A circular type apparatus having an extended line is disclosed in Japanese Patent Publication No. 16558/1975, as well as in Japanese Patent Laid-open Publication No. 141995/1978. The length of the extended line, however, is only twice as large as that of the conventional barrel.
The vibratory barrel finishing apparatus disclosed in the Japanese Patent Publication No. 16558/1975 has a vibrator disposed at the center of the vibratory machine body. The finishing barrel has a corner angle which is a right angle or an acute angle and has a separating device projecting from the barrel body. Thus, this apparatus has an assymmetrical construction and, therefore, cannot be incorporated in a processing line. It is presumed that this apparatus cannot provide a satisfactory processing effect.
The Japanese Patent Laid-open Publication No. 141995/1978 states that "It makes possible to incorporate not single vibrator but a plurality of vibrator in the space extending along the length of the barrel." Judging from the above-statement, as well as from the attached FIGS. 1-9 and associated description which lacks a consideration of synchronized rotation of unbalanced weights, it is considered that the inventor of this invention has made a serious mistake. Namely, it is known that non-synchronized vibrations of a plurality of vibrators applied to the mass in the barrel causes a random movement of the mass or overflowing of the mass from the barrel. The aforementioned Japanese Patent Laid-open Publication No. 141995/1978 teaches how to overcome the above-mentioned problem by inclining the barrel wall outwardly. This, however, complicates the construction extraordinarily and causes a rise of the cost, as well as suppression of the finishing effect due to an obstruction of the flow of the mass.