Abstract: The invention is an inner seal collar for inserting into pipes in order to seal leakage points in the pipes, comprising an expandable strip which is bent into the shape of a ring and which is preferably made of steel sheet, parts of the strip at least partly overlapping in the circumferential direction, and comprising a locking device which has at least two parallel rows of teeth, wherein a separate clamping pinion engages into at least two of the rows of teeth. The invention comprises a separate blocking pinion paired with each of the at least two clamping pinions, the blocking pinion pushing against the corresponding clamping pinion via a respective spring element and being engaged with the clamping pinion, and each of the blocking pinions is also engaged with the corresponding row of teeth.