Abstract: A lens barrel includes: a fixed frame; a zoom ring rotatably held around an outer periphery of the fixed frame; a contact member; and a biasing member. The zoom ring has a first sliding surface to a fourth sliding surface. When the contact member moves on the first sliding surface, a first load is applied to the biasing member; when the contact member moves on the second sliding surface, a second load greater than the first load is applied to the biasing member; and when the contact member moves on the third sliding surface, a load which varies in a range from the first load to the second load is applied to the biasing member.

Abstract: A lens barrel includes: a fixed frame; a zoom ring rotatably held around an outer periphery of the fixed frame; a contact member; and a biasing member. The zoom ring has a first sliding surface to a fourth sliding surface. When the contact member moves on the first sliding surface, a first load is applied to the biasing member; when the contact member moves on the second sliding surface, a second load greater than the first load is applied to the biasing member; and when the contact member moves on the third sliding surface, a load which varies in a range from the first load to the second load is applied to the biasing member.

Abstract: A magnetic recording and reproducing system including a reel base for supplying or taking up a tapelike magnetic recording medium, and a tension band for braking the reel base, which is wound around the reel base through a predetermined angle. First and second retainers are provided for holding opposite ends of the tension band, respectively. The first and second retainers are pivotally attached to a pivotal tension arm. The tension arm has a tension post so that the magnetic recording medium is brought into sliding contact with the tension post. An urging member is provided for adjusting the tension of the magnetic recording medium to a desired value. The system also includes a control member which has a contact portion capable of being brought into contact with a guide portion of the second retainer.

Abstract: A magnetic recording and reproducing device according to the present invention is designed such that when a holding, moving and driving unit is pivoted for recording or reproducing operation which is of frequent occurrence, a pivot shaft of metal which drives for rotation the holding, moving and driving unit is rotated by being supported by and in friction contact with a bearing which is formed of a portion of a base of metal for the sake of driving for pivotal movement, thereby reducing changes with time to members which changes are produced by forces on the pivot shaft which forces, in turn, are caused by reaction forces from the cassette.