Abstract: A monitoring apparatus comprising a lens structure includes lenses and a reflector element which reflects the light rays passing through these lenses, thereby changing the first optical axis along which the light rays pass before being reflected into the second optical axis and which is further equipped with a camera element for taking the picture image of the object body which has been reflected from the reflector element and a drive for rotating the lens structure, with this second optical axis extending along its center, to enable monitoring of a wide field of vision.

Abstract: In a cassette casing having a supply reel, a take-up reel and a hollow cylindrical member, a magnetic tape is fed from the supply reel and, after having been spirally wound around the intermediate hollow cylindrical member, is wound on the take-up reel. To this end, the hollow cylindrical member is formed with a spiral guide rib with a pitch substantially equal to the width of the magnetic tape and threadedly or screwwisely received in an opening formed in the bottom plate of the cassette casing. When the cassette casing is placed in the position in which it is ready for operation within a video recording and reproducing apparatus, a rotatable magnetic head drum having a magnetic head is inserted into the cylindrical member. Thereafter, the cylindrical member is moved outwardly from the cassette casing by rotating it through a driving apparatus, whereby the magnetic tape wound around the cylindrical member is progressively transferred onto the head drum to the position for recording or reproducing.

Abstract: In a rotary head type magnetic tape video recording-reproducing device of the type in which a magnetic tape from a supply reel is wrapped around a rotary drum carrying magnetic heads along the path of revolution thereof at an angle other than 0.degree. relative to the axis of rotation of said rotary drum, and is taken up by a take-up reel for recording or reproducing, when a stop button is depressed or the power supply to a take-up reel driving motor is interrupted, the motor is stopped and then immediately reversed in direction for a predetermined time, thereby loosening the tension of the magnetic tape. This arrangement prevents the adhesion of the magnetic tape to the surfaces of the magnetic tape passages, especially of the rotary drum, due to the moisture or the condensation of vapor so that the smooth re-starting of the magnetic tape may be ensured.

Abstract: A tape cassette for a helical scan type recording and reproducing apparatus comprising upper and lower cylindrical members capable of engaging with each other and adapted to accept a magnetic head therein, and movable poles connected with the upper cylindrical members and capable of stretching a tape outward to prevent contact with various parts of the recording and reproducing apparatus in loading and retrieving the tape cassette. The upper cylindrical member has a helical projection to engage with a helical groove formed in a support member so that it moves also vertically with the rotation thereof so as to expose the magnetic head and take up the tape.