Design of a Novel Cover of the Reflecting Schmidt Plate of the LAMOST

Based on various designs and tests a novel lightweighted curtain-type design of cover has been successfully implemented to meet the requirements of special protection and functions of the LAMOST reflecting Schmidt plate.In this paper,we first review the technical requirements for the cover. Before the final design is adopted,we investigated two prototypes of covers.Our subsequent work has been focused on the mechanical design, electronic control,and on-site installation/debugging of the cover of the novel design.The main functional part of the cover is a lightweighted curtain which is simply adapted from pieces of parachute cloth.On each side of the curtain,there is a group of sliders residing in a curved rail of a C-shaped cross section and driven by two groups of motors (two in each group)through a cable.The motors on two sides drive the opening and closing of the curtain under automatic control.Particularly,the ends of both rails can be folded by electrically controlled pull-push mechanisms to avoid mechanical interference so that the Schmidt plate can cover all the required inclination range (including the vertical orientation of the plate).The cover has been working propering on the LAMOST telescope,which confirms its secureness and reliability.