Device for transmitting optical signals between two structural units (1, 2) that are rotatable relative to one another, wherein the first structural unit comprises - a first lens (1.2), - a first bearing ring (1.3, 1.3') and - a first clamping sleeve (1.5), which has a conical surface (1.51), and the second structural unit comprises - a second lens (2.2), - a second bearing ring (2.3, 2.3'), - a second body (2.4, 2.4'), - a second clamping sleeve (2.5), which has a conical surface (2.51), and - a clamping element (2.6, 2.6'), wherein the first bearing ring (1.3, 1.3') and the second bearing ring (2.3, 2.3') are assigned to a bearing (3, 3') by which the first structural unit and the second structural unit are connected together so as to be rotatable about an axis, and in each case - the first lens (1.2) has been secured to the first bearing ring (1.3, 1.3'), centrally with respect to the axis, by a first conical connection (I; I') with the aid of the first clamping sleeve (1.5), - the second lens (2.2) has been secured to the second body (2.4, 2.4'), centrally with respect to the axis, by a second conical connection with the aid of the second clamping sleeve (2.5), characterized in that: the second body (2.4, 2.4') has been secured to the second bearing ring (2.3, 2.3'), centrally with respect to the axis, by a third conical connection (III, III') with the aid of the clamping element (2.6, 2.6'); and the first structural unit has a sleeve (1.4), which is arranged radially between the first clamping sleeve (1.5) and the first bearing ring (1.3), such that the first conical connection has been established by the first clamping sleeve (1.5) and the sleeve (1.4), or the first bearing ring (1.3') has a conical surface (1.31'), wherein the first conical connection (I') has been established by the first clamping sleeve (1.5) and the conical surface (1.31') of the first bearing ring (1.3'). - a first lens (1.2), - a first bearing ring (1.3, 1.3') and - a first clamping sleeve (1.5), which has a conical surface (1.51), and - a second lens (2.2), - a second bearing ring (2.3, 2.3'), - a second body (2.4, 2.4'), - a second clamping sleeve (2.5), which has a conical surface (2.51), and - a clamping element (2.6, 2.6'), wherein the first bearing ring (1.3, 1.3') and the second bearing ring (2.3, 2.3') are assigned to a bearing (3, 3') by which the first structural unit and the second structural unit are connected together so as to be rotatable about an axis, and - the first lens (1.2) has been secured to the first bearing ring (1.3, 1.3'), centrally with respect to the axis, by a first conical connection (I; I') with the aid of the first clamping sleeve (1.5), - the second lens (2.2) has been secured to the second body (2.4, 2.4'), centrally with respect to the axis, by a second conical connection with the aid of the second clamping sleeve (2.5), the second body (2.4, 2.4') has been secured to the second bearing ring (2.3, 2.3'), centrally with respect to the axis, by a third conical connection (III, III') with the aid of the clamping element (2.6, 2.6'); and the first structural unit has a sleeve (1.4), which is arranged radially between the first clamping sleeve (1.5) and the first bearing ring (1.3), such that the first conical connection has been established by the first clamping sleeve (1.5) and the sleeve (1.4), or the first bearing ring (1.3') has a conical surface (1.31'), wherein the first conical connection (I') has been established by the first clamping sleeve (1.5) and the conical surface (1.31') of the first bearing ring (1.3').