Abstract: A plunger for a syringe may include a plunger head for fluid dense limiting a fluid chamber of the syringe, and a piston rod fixed to the plunger head. The piston rod may be formed by several longitudinally extending axial webs that have an outwardly radial extension from the longitudinal axis and lead into a common crossing section. A free activation edge, which radially protrudes the radial extension, may be provided on the piston rod and engageable with a vibration activator of a hollow body of the syringe to emit an acoustic signal. A swinging arm body may be arranged between two axial webs and couple the activation edge with the crossing section such that in case of a vibration activation in an axial direction the swinging arm body has a radial swinging arm length between the activation edge and the crossing section of at least 40% of the radial extension.

Abstract: A plunger for a syringe may include a plunger head for fluid dense limiting a fluid chamber of the syringe, and a piston rod fixed to the plunger head. The piston rod may be formed by longitudinally extending axial webs that have an outwardly radial extension from the longitudinal axis and lead into a common crossing section. A free activation edge, which radially protrudes the radial extension may be provided on the piston rod and engageable with a vibration activator of a hollow body of the syringe to emit an acoustic signal. A swinging arm body may be arranged between two axial webs and couple the activation edge with the crossing section such that in case of a vibration activation in an axial direction the swinging arm body has a radial swinging arm length between the activation edge and the crossing section of at least 40% of the radial extension.

Abstract: For a plunger for a syringe, particularly an injection syringe, which comprises a hollow body receiving the plunger, comprising a plunger head for fluid dense limiting a fluid chamber of the syringe, and a piston rod fixed to the plunger head with an actuation section, at which the plunger can be actuated for inserting into the hollow body, wherein the piston rod is formed by several longitudinally extending axial webs that comprise an outwardly radial extension rK from the longitudinal axis and lead into a common crossing section, which receives the longitudinal axis, wherein at least one free activation edge, which radially protrudes the radial extension rK, is provided on the piston rod, which when inserting the plunger, is engageable with a vibration activator of the hollow body such that an acoustic signal is emitted, it is intended, that a swinging arm body arranged between two axial webs couples the activation edge with the crossing section such that in case of a vibration activation in an axial direct