Patent ID: 9713677
Date: 2017-07-25
CPC Classifications: A61M,H05K

Claim:
1. A method of operating a drive mechanism for use with an automatic medicament delivery device and notifying a user of medicament expulsion from the automatic medicament delivery device, the method comprising the steps of, a) providing a tubular housing having a proximal end and a distal end; b) providing a tubular extension member having an inner surface; c) slidably engaging a hollow tubular plunger rod having an outer surface within the inner surface of the tubular extension member, where the plunger rod has a proximal wall configured to engage and drive a slidable stopper within a medicament container; d) positioning a first resilient member inside the plunger rod, e) pre-tensioning the first resilient member in a pre-tensioned state so as to exert a force on the proximal wall of the plunger rod prior to activation; f) providing an engaging surface on the outer surface of the plunger rod; g) projecting a resilient tongue radially inward from the tubular extension member, the resilient tongue releasably engaged with the engaging surface to prevent axial movement of the plunger rod in a proximal direction and to maintain the first resilient member in the pre-tensioned state, h) slidably positioning an activation member within the tubular housing and rotatably fixed relative to the tubular housing, where the activation member is configured to activate the device; and i) engaging a second resilient member with and exerting a biasing force on the activation member in a proximal direction; and j) configuring a signal generating member to transmit an audible sound after activation to signal complete expulsion of medicament from the medicament container.