The device (8) has a blocking mechanism (61) arranged between a lower part of a support frame (28) and a lower part of front edge of a herb container (7) so as to connect the lower part of the container on the frame. The mechanism includes an engagement axle (64) arranged in the container. The mechanism includes a helicoidal spring (67) producing retaining and engagement force between the engagement axle and a hook (63) that co-operates with a blocking retaining element (65). A switching mechanism controls the force produced by the spring.
