A device for locking a beam to an upright column. The beam is provided with hooks adapted to be inserted into holes in the upright column and to be locked by a member which is a part of a spring-activated lock device. The lock device can be extracted and moved to a position in which a first stop surface of the device rests on the outside of the beam below the hole. When the lock device is moved to a position such that a second stop surface of the lock device upon insertion of the beam into an upright moves the member to a locking position of the beam to the column.

The post is hollow and provided on one of the sides thereof with two longitudinal rows of openings having a generally T-shape, the lateral walls of the openings being convergent at the end thereof remote from the bar of the T. The rail is rigid with an L-shaped end plate which has a side parallel to the side of the post provided with the openings, which side carries projecting triangular tabs. The tabs are adapted to pass through the bars of the T of the openings and to bear on each side of the rectilinear part of the opening. A boss is locked between the convergent walls.

An upright adjustable rail mounting assembly for adjustably attaching horizontally mounting rails to a pair of slotted uprights by use of an adjustable locking bracket. The rail flanges facilitate mounting of a container assembly provided with means for engagement with the rails. The bracket and rail mounting assembly permit fractional adjustment vertically, and the locking bracket is removable for compact shipping. An alternative locking bracket has a bend to prevent angular disorientation of the bracket with respect to the mounting rail.

In connection means comprising a hook projecting from one structure member and shaped for engagement with an elongated hole having a portion of downwardly tapered shape in another structure member, the hook is complemented by a boss which projects from the same face of the said one member, but spaced from the hook in the vertical direction, and which engages in a said hole in the other member. In a preferred embodiment, the boss is of a shape, for example a truncated pyramid with a trapezium base, engageable by its sides with the sides of the same hole with which the hook is engaged. The hook and boss are integral with the said one member, the boss being disposed closely above the hook from which it is separated by a transverse web. The sides of the boss are undercut. A spring-loaded locking device may be provided in conjunction with the boss.

The specification discloses a furniture system in which a furniture unit is hung on a support by means of hooks which hook into apertures in the support, the unit being locked in place by a lock which is biased into engagement with one of the apertures in the support. The lock and furniture unit in which it is mounted include a detent system which holds the lock in an unlocked position when engaged, enabling one to remove the furniture unit from the support without having to simultaneously manually hold the lock in an unlocked position. The lock and the support further include an automatic release system which automatically releases the detent when the unit is first hooked into the support whereby the lock automatically snaps into its locked condition.