Research On The Grab Open-closed Problem And Steel Wire Vibration Of Four-Drum Grab Unloader

Nowadays, the grab bucket ship-unloader is the main mechanical equipment which is used on bulk cargo port all over the world. In order to suit for the upsizing high-speed development, the grab bucket ship-unloader have experienced many development. On grab driven-way, it have experienced several develop progresses. For example: automatic guided vehicle, towing vehicle, four-reel which include differential planet gear, electrical differential. The deadweight of the automatic guided vehicle is so heavy that towing vehicle and four-reel gradually be widely used on large grab bucket ship-unloader. four-reel vehicle rope-round system are increasingly accepted by customers because it is simple and convenient .With the study and manufacture of large grab bucket ship-unloader, there are two prominent problems. One is the grab bucket can not open and close at certain positions. The other is that open-closed rope and supporting rope change quickly from relaxation to tension when the grab bucket working .At the same time the wire cables will violent bounce.The article focus on the open and close of grab bucket of four-reel grab bucket ship-unloader and analyses the specific parameter relations between span ,unit mass ,tension and sag of wire cable and deduces the specific transform formulas. Combined with concrete examples and the formulas above-mentioned and all kinds of restrictive conditions, the wire cable with certain span and the open and close of grab bucket are analyzed in this paper .It also simplifies the great amount computational processes by procedures compiled through VB language. Combined with the actual work situations of four-reel grab bucket ship-unloader, based on the study of the vibration of elastomer, this paper analyzes the vibration of wire cable on drooping position, discusses the differences between the vibration of string and wire cable, relates the actual progresses of vibration of wire cable in detail and simple explains the possible influence caused by the neglected and interrelated factors during model building processes.In a word, the study on the drooping and vibration of wire cable can not only be used on four-reel grab bucket ship-unloader but also on shore bridge and other kinds of cranes.