Abstract: An assembly for anchoring and lockably securing articles such as tool storage boxes to the bed of a pick-up truck includes an elongated hollow beam fastenable to a truck bed and having through one wall thereof a plurality of longitudinally spaced apart perforations. Elongated members that are securable at a rear-end thereof to a tool box or other such article have enlarged heads that are insertable through the perforations in the beam wall. A locking bar longitudinally slidably held within the beam is provided with a plurality of longitudinally spaced apart cutout sections alignable with the perforations through the beam wall with the locking bar in a first, unlocked position in which the locking members may be inserted through the perforations and cutout sections. With the locking bar slid to a second locking position, portions of the locking bar engage the heads of the locking members protruding inward through the perforations, thereby preventing withdrawal of the locking members.