A stitcher (1) for connecting strips of rubber material (4, 5) into a substantially continuous strip according to this invention comprises a surface (3), a stitching head (6) placed over it having a stitch unit (7) for stitching the strips of rubber material together along a stitch line, which stitch line includes an angle having a longitudinal direction (L) of the continuous strip, a drive mechanism for driving a relative movement of the stitching head with respect to the surface along a first (X) and a second (Y) direction, wherein the second direction is oriented transverse to the first direction, and a control device (11) for controlling the drive mechanism such that the stitch unit follows the stitch line. In one embodiment the stitching head is rotatably connected to the drive mechanism wherein the axis of rotation extends transverse to the surface. The stitching head furthermore comprises a wheel (15) that is placed at a distance from the axis of rotation, wherein the wheel with its tread abuts the surface.

An auxiliary tool for fixing a free end of an adhesive tape wrapped around a strand comprises a base plate and a rotatable ring with a receptacle.

The invention provides a sonotrode (100) for welding a material, the sonotrode (100) comprising a welding section (110) configured for contacting the material, wherein the welding section (110) defines a rounded shape (111) in a cross-section parallel to a longitudinal axis (A) of the sonotrode (100), wherein the rounded shape (111) approximates a circular sector (20), wherein the circular sector (20) has a central angle .sub.c selected from the range of 25-300, and wherein the circular sector (20) has a central radius r.sub.c selected from the range of 5-30 mm, and wherein the sonotrode (100) has a width W perpendicular to the longitudinal axis (A) [and to the cross-section], wherein W is selected from the range of 10-100 mm.