Abstract: A case provided with an information carrier consisting of a tape, one side of which has a structure carrying optically readable information as well as an apparatus for writing, reading or erasing such information. In the dustproof case containing a tape having on one side a structure carrying optically readable information, the tape is accomodated on two reels. The case is provided with one window through which a part of the tape between the reels is visible and with pressing means for urging that visible part of the tape against the window. This pressing means may be a wheel and the window may have the shape of a cylindrical lens.

Abstract: An apparatus for controlling the monoplanar motion of an object, more in particular a tape containing optically readable information, comprising two opposite clamping means on either side of the object. The object as well as at least one of the clamping means are accommodated within a dustproof case. One of the clamping means can be moved relative to the other by generating an (electro)magnetic field outside the case.

Abstract: A case provided with a conveying means for conveying tape-like information carrier as well as an apparatus for writing, reading or erasing information to be utilized in combination with such a case. A case for an information carrying tape, provided with two reels. No rotary parts extend through the wall. Each reel is rotatably mounted and can also move axially between a position in which it is locked and one in which it can rotate. If no (electro)magnetic field is present each reel is in the locked position. If outside the case a rotary (electro)magnetic field is generated which penetrates to a reel, this reel is moved from the locked into the unlocked position and subsequently rotated by the field.

Abstract: A transmission apparatus utilizes the shear resistance in the laminar flow of hydraulic fluid in the active gap between the opposing surfaces of the transmission plates in order to control the transmission of torque. The apparatus comprises at least one plate having a perforated active surface and provided with at least one flowpath away from the active surface, the flowpath connecting the perforations with the non-active space around the perforated plate, and at least one corresponding plate having a non-perforated active surface spaced apart from the active surface of the perforated plate by an active gap. The active gap, the perforations, and the flowpath are arranged and dimensioned such that the resistance to radial flow in the gap is several times the resistance to flow through the perforations and the flowpath in order to create and maintain in the gap at a tangential laminar flow without an effective radial flow component.