attached as well the sleeve could also be welded onto the slat corner sleeve member 22 has a flat top section 25 which compliments outward edge 24 of slat 12 sleeve member 22 has vertically extending side segments 34 36 which extend alongside the long flat sections of slat 12 side segments 34 36 can be of equal length as generally shown in fig2 and 5 as is commonly understood slats 12 typically contain a heddle rod 38 defined along the length thereof for receipt of the heddles along the length of slat 12 side segments 34 36 preferably extend at least to heddle rod 38 in an alternative embodiment the length of side segments 34 36 are different as illustrated in fig1 and 3 for increased rigidity and stability it may be preferred to extend one of the side segments beyond the heddle rod 38 on the opposite side of slat 12 sleeve members 22 can be attached to slats 12 in any conventional manner including adhesives welding or mechanical attaching devices in the embodiments illustrated locking mechanisms 20 include at least one bolt 26 which extends through outward edge 24 of slat 12 bolts 26 engage in a device which is housed within opening 16 of slat 12 an example of this type of conventional device is illustrated and described with particularity in u s pat no 5 477 889 bolts 26 can also be used to.