US Patent 7448139 Surveying stake cap

A survey marker cap assembly (20) includes a cylindrical body (22) that has a top (34) with a connection shaft (38) that extends upwardly from the center of the top (34) through a hole (42) presented by a circular disk (40) that is placed upon the top (34) of the cylindrical body (22). The connection shaft (38) presents a dome (44) that extends radially over the disk (40) to secure the disk (40) upon the cylindrical body (22) and the dome (44) presents a female dimple (46) therein for centering with a plumb bob. The cylindrical body (22) and disk (40) consist of the same or different metals and the cylindrical body (22) includes threads (32) disposed there within for placement on a surveying stake.