Device for simultaneously masking and bracing a plurality of hairpin arrangements to be welded, in particular hairpin pairs, of a stator, wherein (i) the plurality of hairpin arrangements are distributed in a circumferential direction on a plurality of concentrically arranged circular paths (16a, 16b, 16c) or on portions of concentric circular paths (16a, 16b, 16c) such that (ii) the hairpin arrangements are arranged in radially aligned rows which are spaced apart from one another in the circumferential direction via radial gaps extending in the radial direction, and wherein (iii) the individual hairpin arrangements in a radially aligned row are spaced apart from one another in the radial direction via annular gaps (18a, 18b) extending between the concentrically arranged circular paths (16a, 16b, 16c), wherein the device comprises: (a) a positioning unit for positioning the device with respect to the stator to be machined, (b) a masking unit which comprises a plurality of openings (80a, 80b, 80c, 80d) for each receiving one of the plurality of hairpin arrangements arranged in the radially aligned row, wherein the plurality of openings (80a, 80b, 80c, 80d) are delimited by circumferential sides (73a, 73b), which are opposite one another in the radial direction and extend in the circumferential direction, and by radial sides (71a, 71b) of the masking unit, which are opposite one another in the circumferential direction and extend in the radial direction, (c) an actuating unit which is designed to be movable relative to the positioning unit, (d) a first coupling unit (40a, 40b), by means of which the actuating unit and the positioning unit are operatively coupled to the masking unit such that a relative movement between the positioning unit and the actuating unit causes a movement of the circumferential sides (73a, 73b) toward one another in the radial direction in order to mask and brace the hairpin arrangements received in the openings (80a, 80b, 80c, 80d) in the radial direction, wherein the first coupling unit comprises at least one first coupling element (42a, 42b), and (e) a second coupling unit, by means of which the actuating unit and the positioning unit are operatively coupled to the masking unit such that the relative movement between the positioning unit and the actuating unit causes a movement of the radial sides (71a, 71b) toward one another in the circumferential direction in order to mask and brace hairpin arrangements received in the openings (80a, 80b, 80c, 80d) in the circumferential direction, wherein the second coupling unit comprises at least one second coupling element (52a, 52b). (i) the plurality of hairpin arrangements are distributed in a circumferential direction on a plurality of concentrically arranged circular paths (16a, 16b, 16c) or on portions of concentric circular paths (16a, 16b, 16c) such that (ii) the hairpin arrangements are arranged in radially aligned rows which are spaced apart from one another in the circumferential direction via radial gaps extending in the radial direction, and wherein (iii) the individual hairpin arrangements in a radially aligned row are spaced apart from one another in the radial direction via annular gaps (18a, 18b) extending between the concentrically arranged circular paths (16a, 16b, 16c), (a) a positioning unit for positioning the device with respect to the stator to be machined, (b) a masking unit which comprises a plurality of openings (80a, 80b, 80c, 80d) for each receiving one of the plurality of hairpin arrangements arranged in the radially aligned row, wherein the plurality of openings (80a, 80b, 80c, 80d) are delimited by circumferential sides (73a, 73b), which are opposite one another in the radial direction and extend in the circumferential direction, and by radial sides (71a, 71b) of the masking unit, which are opposite one another in the circumferential direction and extend in the radial direction, (c) an actuating unit which is designed to be movable relative to the positioning unit, (d) a first coupling unit (40a, 40b), by means of which the actuating unit and the positioning unit are operatively coupled to the masking unit such that a relative movement between the positioning unit and the actuating unit causes a movement of the circumferential sides (73a, 73b) toward one another in the radial direction in order to mask and brace the hairpin arrangements received in the openings (80a, 80b, 80c, 80d) in the radial direction, wherein the first coupling unit comprises at least one first coupling element (42a, 42b), and (e) a second coupling unit, by means of which the actuating unit and the positioning unit are operatively coupled to the masking unit such that the relative movement between the positioning unit and the actuating unit causes a movement of the radial sides (71a, 71b) toward one another in the circumferential direction in order to mask and brace hairpin arrangements received in the openings (80a, 80b, 80c, 80d) in the circumferential direction, wherein the second coupling unit comprises at least one second coupling element (52a, 52b).