| 摘要 |
The columns (4, 5) or spindles (4.1) are held against rotation in the fixed mold platen (2). The spindle nut is coupled rigidly with the rotary bush (17) which has an engagement connecting the bush on build-up of closure pressure, in direct, long-line contact with the spindle. During opening and closure of the moving platen (3), this rotates freely with the bush, relative to the spindle. The bush is coupled to the rotary drive (14, 15) and is mounted for axial motion in bearings in the moving platen. The bush is held fixed with a frictional connection; this is coupled against rotation by axial sliding relative to the moving platen. The spindle nut in the rotary bush is axially supported by a fixed stop on the moving platen remote side; on the other side it is axially supported by a first spring unit. Between the fixed bearing support and the moving platen, a second spring unit is located. Its spring constant exceeds that of the first. The spring constant of the first unit is co-ordinated, such that when opening and closure is effected by the spindle drive (12, 13), both first and second spring units remain undeflected. The rotary bush is positioned relative to the spindle nut by resting on the first stop on one hand and by resting against the undeflected spring unit on the other. Positioning is such that the rotary bush is disengaged from the spindle in this state. The spring constant of the second unit is so selected that when closure force is imposed through the spindle, the first spring unit is initially compressed, whereupon the rotary bush moves relative to the spindle nut such that complete frictional engagement of the rotary bush is achieved with the spindle. Then the second spring unit is compressed, causing axial sliding of the rotary bush relative to the moving platen. This locks the frictional coupling. Further preferred details of the closure unit are provided, covering thread form, rotary bush engagement, conical clamping and the braking ring system. Closure force is applied by one or more hydraulic units. Drive is effected by an electric motor turning the spindle nut.
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