|Title:||Drive mechanisms suitable for use in drug delivery devices|
|Abstract:|| The present disclosure is directed to a dose setting mechanism that may be used with a drug delivery device. The dose setting mechanism may include an inner body having a helical thread along an outer cylindrical surface of the inner body, and a drive sleeve for driving a piston rod in an axial direction, the drive sleeve positioned within at least a portion of the inner body. The dose setting mechanism may further include a dose dial sleeve rotatably engaged with the helical thread of the inner body and a dial grip connected to the dose dial sleeve and releasably connected to the drive sleeve. Further when a dose is set, the dial grip is rotated so that both the dose dial sleeve and the drive sleeve rotate with respect to the inner body.|
|Inventor(s):|| Veasey; Robert Frederick (Warwickshire, GB), Langley; Christopher Nigel (Warwickshire, GB), Wimpenny; Steven (Warwickshire, GB) |
|Assignee:|| SANOFI-AVENTIS DEUTSCHLAND GMBH (Frankfurt Am Main, DE) |
|Filing Date:||Oct 01, 2014|
|Claims:||1. A disposable injection device comprising, an exterior housing having a first part and a second part permanently connected to each other, where the exterior housing contains a multi-dose cartridge of medicament containing a displaceable piston and a dose setting and delivery mechanism, where the exterior housing has a first end where the medicament is expelled during dose delivery and a second end where a user sets a dose by rotating a dose dial grip that is part of the dose setting and delivery mechanism, where the dose setting and delivery mechanism further comprises, a) a web rotationally fixed to an inside portion of the external housing and comprising a threaded circular opening; b) a non-circular cross section piston rod having a threaded outer surface threadedly engaged with the circular opening in the web, where a first end of the piston rod has a pressure foot abutting a second end of the displaceable piston in the multi-dose cartridge, and where the piston rod is configured to rotate and translate towards the first end of the exterior housing causing the displaceable piston to move axially to expel a set dose; c) a nut having external splines, where the nut is configured to, i) rotate relative to the piston rod during dose setting, ii) move an axial distance proportional to a set dose, and iii) not rotate relative to the piston rod during dose delivery; d) a spring configured to store energy during dose setting and to release the stored energy during dose delivery causing the piston rod to rotate and translate axially through the web; e) a dose dial sleeve configured, i) to threadedly engage with the exterior housing, ii) to be axially displaceable relative to the piston rod during dose setting, and iii) to rotate with the piston rod during dose delivery; and f) a unidirectional coupling configured to prevent rotation of the piston rod during dose setting and to allow the piston rod to rotate during dose delivery, where the dose dial grip is releasably engaged with a cylindrical drive sleeve that extends about the piston rod, where the releasable engagement is through a clutch such that during dose setting the drive sleeve and dose dial grip are rotationally fixed, and where axial movement of the drive sleeve releases the stored energy in the spring to cause the piston rod to rotate and translate through the circular opening in the web. |
2. The mechanism of claim 1 further comprising a "T" shaped dose button configured to be depressed to deliver a set dose and to drive the drive sleeve in an axial direction.
3. The mechanism of claim 1 where further comprising a dose dial sleeve having an external surface with numerals indicative of a set dose.
4. The mechanism of claim 1 further comprising a clicker associated with the drive sleeve and configured to cause a series of audible and tactile clicks upon dose setting and dose delivery.
5. The device of claim 1 further characterized in that the nut is configured to prevent setting of a dose greater than a remaining amount of medicament in the cartridge.
6. The mechanism of claim 1 further characterized in that the nut does not rotate relative to the drive sleeve.