Covering plate

Abstract

A cover plate comprising:a body (111) comprising a first sub-part (113), a second sub-part (114), a third sub-part (115) and a fourth sub-part (116), wherein:the first sub-part (113) is adjacent to an edge of the body (111) along a radial direction of the body (111);the second sub-part (114) is adjacent to the first sub-part (113) and comprises a recessed member (1141) and a projection (1142) which are connected and located on the same circumference, characterised in that the second sub-part (114) further comprises a first side surface (1143) and a second side surface (1144) which are opposite to each other, and the projection (1142) is located higher than the recessed member (1141) and the first sub-part (113) in the second in a direction extending from the side surface (1144) to the first side surface (1143);andthe third sub-part (115) is concentric with the second sub-part (114) and circular, and the recessed member (1141) and the projection (1142) are enclosed in a closed ring,the fourth sub-part (116) is located between the second sub-part (114) and the third sub-part (115), wherein the fourth sub-part (116) is annular, and the fourth sub-part (116) is connected to the second sub-part (114) and the third sub-part (115),the cover plate (110) includes an explosion-proof groove (120) including a first groove section (121) and a second groove section (122), wherein the first groove section (121) is at least partially located on the recessed member (1141) and the second groove section (122) is located on the projection (1142).;