Abstract: A cylinder lock having a removable barrel that includes a control tumbler. The barrel is retained in the housing of the lock by a nib that is formed on either the barrel or the interior of the housing. A longitudinal nib slot is formed on the other of either the barrel or the interior of the housing. The nib and the nib slot are aligned with one another only when the barrel is in an unlocking position for permitting the barrel to be removed from the housing. In this manner, the barrel may be removed from the housing only when both the barrel is in the unlocked position and when a special control key has been inserted into the barrel for withdrawing the control tumbler into the barrel.

Abstract: A fastener unit for use on a composite nonmetallic surface which includes a channel of composite nonmetallic material, which may be bonded or riveted to the supporting surface, and has at least one opening through it, and a fastener assembly which includes a basket having an opening in its center and slotted deflectable end walls, a retainer member, including a flat portion with tabs projecting into openings in the side flanges of the channel and a tubular portion extending into the opening in the central web of the channel, and a nut having a base portion with tabs received in the openings in the end walls of the basket. Clearances are provided so that the nut has limited lateral floating movement. The nut is removable from the remainder of the unit by deflecting the end walls of the basket, which permits the nut to be replaced.