A positioning system comprising a first working element having a first tubular shaft with a first longitudinal center axis and having a receiving section, a second working element having a second tubular shaft with a second longitudinal center axis, an arc element with a holding element and a curved rail extending curvedly along an arc direction, wherein the curved rail is arranged on the holding element and the holding element is configured to be detachably and positively fastened on the receiving section by a fastening element, and a guiding element having a holding section and a guiding section, wherein the holding section is adapted to be guided on the rail and the guiding section is adapted to receive the second tubular shaft and guide it in a center direction perpendicular to the arc direction when the holding section is guided on the rail, characterized in that the holding section has a locking element which is configured for positively securing the guiding element to the rail, wherein the locking element blocks displacement of the holding section in a transverse direction in a locking position and allows displacement of the holding section in the transverse direction in a release position, wherein the transverse direction is perpendicular to the direction of the arc and perpendicular to the center direction, and wherein the fastening element comprises a rocker lever having a first projection at a first end and an actuation surface at an opposite second end, wherein the projection is adapted to engage in a groove of the receiving section, and wherein the rocker lever is configured such that the fastening at the receiving section, using the rocker lever can be released or engaged with one hand. a first working element having a first tubular shaft with a first longitudinal center axis and having a receiving section, a second working element having a second tubular shaft with a second longitudinal center axis, an arc element with a holding element and a curved rail extending curvedly along an arc direction, wherein the curved rail is arranged on the holding element and the holding element is configured to be detachably and positively fastened on the receiving section by a fastening element, and a guiding element having a holding section and a guiding section, wherein the holding section is adapted to be guided on the rail and the guiding section is adapted to receive the second tubular shaft and guide it in a center direction perpendicular to the arc direction when the holding section is guided on the rail, characterized in that the holding section has a locking element which is configured for positively securing the guiding element to the rail, wherein the locking element blocks displacement of the holding section in a transverse direction in a locking position and allows displacement of the holding section in the transverse direction in a release position, wherein the transverse direction is perpendicular to the direction of the arc and perpendicular to the center direction, and wherein the fastening element comprises a rocker lever having a first projection at a first end and an actuation surface at an opposite second end, wherein the projection is adapted to engage in a groove of the receiving section, and wherein the rocker lever is configured such that the fastening at the receiving section, using the rocker lever can be released or engaged with one hand.