The mandrel is the key part of hot rolling tension reel for coils. Coiling temperature is between 550 to 850 oC . The mandrel has mainly two types: link wedge type and double wedge type.
Unk wedge type can also be divided into two kinds: link wedge coupling drive and link wedge-spline drIve.
For link wedge-coupling type tension reel, the mandrel is mainly composed of rnandrel body, spreader bar, segment, link, wedge and spreading cylinder Spreader bar has multistage slopes and segment is supported by multistage wedge Segment is connected with spreader bar by link so segment does not drop off With compression spring in the middle of wedge, wedge can firmly contact segment and pyramid surface. There is a gap between the upper surface of wedge and segment, which can reduce the impact of coil head to mandrel during coiling coil. Mandrel body is installed on two bearings. Power is transmitted by crowned-teeth coupling in the rear. It is very convenient to dismantle, and due to there is no gear impact during working. mandrel rigidity is improved. lt’ s very beneficial to control the dynamic tension.
The spreadding principle of mandrel: spreader bar moves inside mandrel body in axial direction driven by hydraulic cylinder, the slant of spreader bar pushes the wedge inside radial hole of mandrel body to move outward The wedge upper surface pushes segment to expand outward Wedge diameter will expand After coiling coils, preader bar moves in the opposite direction driven by hydraulic cylinder, and pulls segment inward to shrink through link Wedge moves inward and mandrel diameter becomes smaller to discharge state Then you can begin to discharge coil.