The present invention relates to a handle assembly (100) for an implant delivery device for folding or unfolding at least one medical implant by means of at least one tension thread, wherein the handle assembly (100) comprises a drum (14) for winding the tension thread thereon by rotating the drum (14); a knob (9) to be rotated by a user of the handle assembly (100) in order to fold or unfold the medical implant, the knob (9) being interconnected with the drum (14) such that the drum (14) is rotated when the knob (9) is rotated; and a displacement limiter for limiting the length or displacement by which the tension thread (11) may be at least one of wound onto or unwound from the drum (14) by rotating the knob (9).