on the first bar 32 over the entire stroke of the carriage 16 furthermore the linear motor is capable of providing a precise dynamic response that allows perfect synchronization with the operating steps of the lathe advantageously in order to protect the sliding guides of the carriage and the gap region against the penetration of dirt that might compromise the efficiency of the linear motor a barrier that closes the compartment 28 in an upward region is arranged above the sliders 24 said barrier is constituted by a first strip 33 which is fixed to the top of the wall 3 and by a second strip 34 which is fixed to the top of the posts 4 the two strips 33 34 protrude longitudinally toward each other and support respectively along their opposite edges a double brush 35 and a single or double brush 36 whose upper bristles engage between the bristles of the double brush 35 the bristles 35 and 36 together with the strips 33 and 34 therefore form a seal of the compartment 28 that however allows the passage of the vertical arms 20 of the brackets 17 and 18 of the carriage 16 the invention is susceptible of numerous modifications and variations shown in fig5 7 and 8 in which the elements and parts that are equal.