Patent ID: 8651988

Claim:
A tensioning device for a traction element, comprising a tensioning arm, a machine part on which the tensioning arm is arranged so that the tensioning arm can pivot, and an idler or deflection pulley mounted on the tensioning arm so that the idler or deflection pulley can rotate via a roller bearing located on the tensioning arm, and a protective cap covers a bearing region of the idler or deflection pulley and is secured on the idler or deflection pulley with a friction or positive fit connection, the idler or deflection roller is a formed sheet-metal sheave consisting of an inner axially extending sheet-metal wall having an end integrally connected with a radially outwardly extending sheet-metal wall, and an outer axially extending sheet-metal wall is integrally connected to an outer end of the radially extending sheet-metal wall, and for connection of the protective cap, the inner axially extending sheet-metal wall includes a snap-in groove, which is formed by deforming a free end region of the inner axially extending sheet-metal wall conically outwardly, and the free end region of the inner axially extending sheet-metal wall has a reduced thickness in comparison to a wall thickness of the sheet-metal walls of the sheet-metal sheave away from the conically outwardly shaped free end region.