towards and away from the crossbars to which they are attached said rail ends facing adjacent guide ends defining the limits of play between the rails and the guides in a well known manner the ends of the healds 10 are associated with strip shaped stops 15 16 mounted on the crossbars 4 5 and which drive the healds 10 in the manner described below in relation to fig2 and 3 the guide elements 13 14 of the lamellar healds 10 are dimensioned in such a way relative to the rails 6 7 that the rails 6 7 shall guide the healds 10 only laterally but will not drive the healds via their ends during lifting and lowering movements the brackets 8 of the rails 6 7 are fastened by screws 9 to the crossbars 4 5 said screws passing through slots 17 of the brackets 8 fig2 running in the longitudinal direction of the healds 10 in this way the position of the rails 6 7 is adjustable in the longitudinal direction of the lamellar healds 10 relative to the crossbars 4 5 when the heald frame is raised in the direction of the arrow a at the middle shed position or when it is at its upper end position then the lower ends of the healds 10 shall rest against the lower damping stop 16 as shown in fig2 when the frame is lowered in the.