Abstract: In a video recorder with a rotary head drum, a lower drum (1) and drum base (2) are joined together by laser welding to simplify assembly and reduce manufacturing cost.

Abstract: According to a first aspect the present invention is related to a head drum arrangement allowing a much easier mounting of the rotary transformer. The head drum arrangement comprises a non-rotating lower drum and a rotating upper drum, which are connected by a shaft fixed in the lower drum. The upper drum is mounted on the shaft by a bearing and preferably by two ball bearings. A rotary transformer is arranged between the lower drum and the upper drum having a fixed stator and a rotor rotating jointly with the upper drum. The rotor is non-positively held in its position by the magnetic force of a permanent magnet accommodated in the upper drum.

Abstract: According to a first aspect the present invention is related to a head drum arrangement allowing a much easier gap adjustment of the rotary transformer. The head drum arrangement comprises a non-rotating lower drum and a rotating upper drum, which are connected by a shaft fixed in the lower drum. The upper drum is mounted on the shaft by a bearing and preferably by two ball bearings. A rotary transformer is arranged between the lower drum and the upper drum having a fixed stator and a rotor rotating jointly with the upper drum. The stator and the rotor are separated by an air gap. Finally, a compressible, elastic spring is arranged between the lower drum and the upper drum, such that the length of the spring defines the air gap between the stator and the rotor of the rotary transformer. Advantageously, the invention allows defining the air gap of the rotary transformer without requiring additional members like washers, spacers or something similar.

Abstract: According to a first aspect the present invention is related to a head drum arrangement allowing a much easier mounting of the rotary transformer. The head drum arrangement comprises a non-rotating lower drum and a rotating upper drum, which are connected by a shaft fixed in the lower drum. The upper drum is mounted on the shaft by a bearing and preferably by two ball bearings. A rotary transformer is arranged between the lower drum and the upper drum having a fixed stator and a rotor rotating jointly with the upper drum. The rotor is non-positively held in its position by the magnetic force of a permanent magnet accommodated in the upper drum.

Abstract: A device for sending and receiving electromagnetic waves comprises an antenna with a waveguide, a sending card and a receiving card. The sending card and the receiving card each extend essentially from the waveguide, and therefore from the antenna axis, in a plane perpendicular to this axis and between them form an angle greater than 90°.

Abstract: The invention proposes the use of a reel, for instance for a device for electromagnetic wave communication, comprising a first component movable in rotation in relation to a second component about an axis and at least one first cable fixed to the first component at at least one point. The first cable is fixed to the second component at at least one point and the first cable is wound spirally about the axis. The reel comprises at least one second cable wound spirally about the axis and separated from the first cable by a first flange perpendicular to the axis.

Abstract: A device for sending and receiving electromagnetic waves comprises an antenna with a waveguide, a sending card and a receiving card. The sending card and the receiving card each extend essentially from the waveguide, and therefore from the antenna axis, in a plane perpendicular to this axis and between them form an angle greater than 90°.

Abstract: As is well known from video recorders, the rotary drum comprises a rotary part (upper drum) and a stationary part (lower drum), and forms a drum unit with a drum base (2) by means of which the drum is being arranged with a tilt angle with respect to the plane of recorder's tape deck chassis.