drive motor 70 rotates the shed forming machine forwardly or rearwardly so that a possibly defective pick can be found and exposed simultaneously with the lever 67 the control lever 17 is swung clockwise which causes the shed forming machine to become uncoupled from the weaving machine the entire pick finding device can also be used as a braking mechanism for the shed forming machine the two teeth 15 and 16 being engaged in comparison to the inventive braking mechanism according to fig2 and 3 the braking mechanism according to fig4 includes the braking disk 60 which is axially movable on the drive shaft 6 the annular frusto conical braking surface 61 and the frusto conical counter surface 63 on the gear 64 the braking disk 60 is moved by the control lever 67 which is pivotally supported by the axle 68 and a roller 66 which is rotatably supported on the lever 67 and received in an annular groove 65 in the disk 60 for starting the braking operation the braking disk 60 is moved to the right by swinging the control lever 67 clockwise which causes the two friction surfaces 61 and 63 to move into frictional contact and to transmit the rotational forces of the drive shaft 6 onto the gear 64 during this braking operation the energy of the shaft 6 is transmitted through the gear 64 and pinion 75 to the drive motor 10 which is under current only a limited amount in order to brake particularly effectively the motor can be a braking or stop motor or a magnetic.