Poles designed for carrying the Ark were affixed to its two sides. These poles were made of acacia wood overlaid in gold. All the vessels of the Mishkan had these carrying poles for traveling in the dessert, and when Israel camped they were removed. Only the poles of the Ark of the Covenant were never removed, by special commandment. These poles reached the curtain and protruded slightly outwards from the curtain in the Kodesh. (Source: Exodus 25, 12-15) 
The Cherubim
Contents:   Part I,    Part II,    Part III,    Part IV,    Part V,    Part VI,    Part VII