be made to blow in the desired direction in order to have the medium flow act on the projectile in both directions it is possible to used guides which are arranged in spaced apart relationship and which blow alternately in one direction and in the other direction furthermore it is possible thereby to use guides which are provided with a partition 50 as is schematically indicated in fig7 as a result of which the channel in said guides is divided into two parts 51 and 52 which channels are connected to different medium supply lines whereby the two sides of the guides are each provided with outlet openings 53 and 54 depending on the direction in which the projectile is to be transported through the section either channel 51 or channel 52 may be supplied with medium as is indicated in fig1 both the introducing station 11 and the decelerating station 10 may be provided with a type of guides similar to guide 7 in introducing station 9 guides 7 will blow medium in the direction in which the projectile is to be transported while in decelerating station 10 guides 7 will blow medium in the direction in which the projectile 8 is to be decelerated from the above it will be apparent that the invention provides a very advantageous weaving device wherein transport energy can be imparted to the projectile during its passage through the weaving section by means of.