the rigid tube 34 of the roller cover 32 thus permitting the roller cover 32 to easily slide over the roller assembly 16 except when tabs 38 are engaged as described below fig4 shows a detailed section view of a portion of the roller assembly 16 with a roller cover 32 mounted thereon the locking lever 18 is in the locked position and the retainers 30 are in the extended position such that tabs 38 are extended radially into contact with the rigid tube 34 of the roller cover 32 in this position the tabs 38 exert sufficient force on the rigid tube 34 of the roller cover 32 that the roller cover is not readily slidable along the roller assembly 16 the roller assembly 16 remains rotatable relative to the shaft 20 it is within the scope of the invention to utilize retainers 30 having other shapes in particular tabs 38 may have alternative shapes or may be comprised of alternative structures for example the tabs 38 may have a sloped profile as discussed below with regard to fig1 further the retainers 30 may include no tabs 38 or an alternative tab structure such as but not limited to a series of small teeth a rubber coating or a coating composed of another non slip material fig5 shows a detailed section view of the same portion of the roller assembly 16 as is depicted in fig4 however the locking lever 18 is in the released position the tabs 38 are retracted radially inward towards the shaft 20.