Patent ID: 8490913

Claim:
A retention mechanism for a dispenser for retaining an end plug of an exchangeable roll of material, the retention mechanism comprising: an insertion slot extending between a receiving end and a seating region for inserting a bearing pin of the end plug, the seating region including seating ribs rigidly fixed to the seating region for maintaining a correct axial position of the bearing pin; the bearing pin being provided with at least two portions, a first portion with a first diameter, and a second portion with a second diameter, the second diameter being smaller than the first diameter and forming a circumferential groove in the bearing pin; a pin discriminator structure which is rigidly fixed to at least the receiving end of the insertion slot and narrows the receiving end of the insertion slot such that the pin discriminator structure protrudes into the circumferential groove when the bearing pin is in the receiving end to allow only bearing pins which have a maximum outer diameter in the second portion substantially equal to or is less than the second diameter to enter the insertion slot; and a rejecting slot extending from the seating region which is dimensioned such that only bearing pins with a predetermined maximum diameter in the first portion which is smaller than the first diameter can enter the rejecting slot, and which extends in a direction that is non-parallel to a direction in which the receiving end extends.