Jacks are also called weightlifters, jacks, jacks, etc. They mainly include hydraulic jacks, screw jacks, horizontal jacks and separate jacks. The screw jack is generally only used for mechanical maintenance work. By pulling the handle back and forth, the pawl will push the ratchet clearance to rotate, and the small bevel gear will drive the large bevel gear to rotate the lifting screw, so that the lifting sleeve can be lifted or lowered to achieve the lifting tension function. According to the relative motion mode of screw and nut, screw drive can have the following four motion modes:
1. The nut is fixed, as shown in Figure(a), the screw rotates and moves back and forth. This structure is mainly supported by the fixed nut, which is simple in structure, but takes up a large space. Commonly used in screw presses, screw jacks, etc.
2. Nut drive, as shown in Figure (b), the screw moves in a straight line, and the screw should be equipped with anti-rotation mechanism. The nut rotation requires bearing, which makes the structure complex, and the screw stroke occupies the size, so the application is less. 3、 The nut rotates and moves in a straight line, as shown in Figure (c), because the screw is fixed, the supporting structure at both ends is relatively simple, but the accuracy is not high. 4、 Screw rotation, as shown in figure (d), the nut moves in a straight line, which takes up a small space and is suitable for long-stroke screw. The bearing and nut anti-rotation mechanism at both ends of the screw make its structure more complex. The moving mechanism of lathe lead screw and tool rest mostly adopts this movement mode. Beijing Lingying Hoisting Machinery Factory, the gold manufacturer of screw jack, is mainly engaged in lifting tools such as jack, sling, manual hydraulic carrier, chain hoist, electric hoist, miniature electric hoist, explosion-proof electric hoist, non-standard electric hoist, wire rope electric hoist, chain hoist, etc.
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