Drug Delivery Device and Method for Eliminating a Clearance of the Piston Rod for Drug Delivery Devices

Patent metadata

Field	Value
Publication number	US-2016015904-A1
Application number	US-201414773326-A
Country	US
Kind code	A1
Filing date	Mar 10, 2014
Priority date	Mar 13, 2013
Publication date	Jan 21, 2016
Grant date	—

Abstract

The piston rod arrangement is in an assembled state before use and comprises a piston rod, a bung, which is intended to be driven by the piston rod, a body member, and a drive member. The piston rod is threadedly engaged with the body member, and the drive member is threadedly engaged with the piston rod and movable relative to the body member. A mechanism is provided defining unit steps of movement of the drive member and corresponding unit steps of movement of the piston rod. The piston rod is arranged in contact with the bung or at a distance from the bung that is less than a distance of one corresponding unit step of movement. When the piston rod, the bung and the drive member are assembled in the body member, the piston rod is advanced with respect to the body member towards the bung, until the piston rod is stopped by the bung. The drive member is rotated until the piston rod begins to advance again and the drive member is then stopped, and the piston rod is fixed at or near the position obtained.

First claim

1 - 18 . (canceled)

19 . A drug delivery device, comprising:
a piston rod arrangement in an assembled state before the first use, comprising
a piston rod,
a bung,
a body member, the piston rod being threadedly engaged with the body member,
a drive member threadedly engaged with the piston rod and provided to advance the piston rod, and
the drive member being movable relative to the body member, a mechanism being provided for defining unit steps of movement of the drive member and corresponding unit steps of movement of the piston rod, wherein
the piston rod is arranged in contact with the bung or at a distance from the bung that is less than a distance of one corresponding unit step of movement.

20 . The drug delivery device according to claim 19 , wherein
the piston rod is arranged at a distance from the bung that is less than a distance of half a corresponding unit step of movement.

21 . The drug delivery device according to claim 19 , wherein
the mechanism defining unit steps of movement is formed by a feature acting between the body member and the drive member.

22 . The drug delivery device according to claim 19 , further comprising:
a dial member coupled with the drive member, wherein the mechanism defining unit steps of movement is provided by a feature formed on the body member and on the dial member.

23 . The drug delivery device according to claim 19 , further comprising: a first part and a second part of the drive member, coupled in such a manner that the first part and the second part can rotate relative to one another, wherein the second part is threadedly engaged with the piston rod.

24 . The drug delivery device according to claim 23 , further comprising:
a button member comprising an operation button, the first part of the drive member being arranged between the second part and the button member, and a first locking feature of the button member, the first locking feature being engaged with a corresponding feature of the first part of the drive member, the first locking feature rotationally locking the button member with the first part.

25 . The drug delivery device according to claim 24 , further comprising:
a second locking feature of the button member, the second locking feature being engaged with a corresponding feature of the second part of the drive member, the second locking feature rotationally locking the button member with the second part.

26 . The drug delivery device according to claim 19 , further comprising:
a first part and a second part of the drive member, wherein the second part is threadedly engaged with the piston rod, and a coupler fastened to the second part, the first part and the second part being releasably rotationally locked by the coupler.

27 . The drug delivery device according to claim 26 , further comprising:
a ramp feature provided on the body member, and a further body member provided with a corresponding ramp feature, the ramp features transforming a relative rotation of the body member and the further body member into a relative shift.

28 . The drug delivery device according to claim 19 , further comprising:
threads threadedly engaging the piston rod with the body member, and further threads threadedly engaging the piston rod with the drive member, wherein the thread of the body member has an area of contact on the body member and the thread of the drive member has an area of contact on the drive member, the areas of contact being in contact with the piston rod in such a manner that no backlash between the drive member, the piston rod and the body member interferes with an advancement of the piston rod by the drive member or that a backlash between the drive member, the piston rod and the body member is so small that the backlash only causes a reduction of the advancement of the piston rod by less than a distance of one corresponding unit step of movement.

29 . The drug delivery device according to claim 19 , wherein the drug delivery device is a disposable device.

30 . The drug delivery device according to claim 19 , wherein the drug delivery device is a variable dose device.

31 . A method for eliminating a clearance of a piston rod for drug delivery devices, comprising the steps of:
assembling a piston rod, a bung, and a drive member provided for generating a movement of the piston rod in a body member in such a manner that the bung is stationary with respect to the body member, and the piston rod is threadedly engaged with the body member and with the drive member, wherein either a) the piston rod is advanced with respect to the body member towards the bung, until the piston rod is stopped by the bung, the drive member is rotated until the piston rod begins to advance again, and the drive member is then stopped, and the piston rod is fixed at or near the position obtained, or b) a frictional force is used to generate a torque acting between the body member and the drive member, the body member is shifted in the direction towards the bung, driving the piston rod into contact with the bung and generating a rotation of the piston rod, which causes a rotation of the drive member against the action of the torque, and the piston rod is driven into contact with the bung against the action of said torque by a force loading the bung with a resilient force.

32 . The method of claim 31 , wherein either
a) the piston rod is advanced with respect to the body member towards the bung, until the piston rod is stopped by the bung, the drive member is rotated thus rotating the piston rod by the threaded engagement of the piston rod with the drive member, until the piston rod begins to advance again relative to the body member by the threaded engagement of the piston rod with the body member; and the drive member is then stopped, and the piston rod is fixed at or near the position obtained, or b) a frictional force is provided acting between the body member and the drive member, the body member is shifted in the direction towards the bung, driving the piston rod into contact with the bung and generating a rotation of the piston rod, by the threaded engagement of the piston rod with the body member, which causes a rotation of the drive member against a torque generated by said frictional force, and the piston rod is driven into contact with the bung against the action of said torque by a force loading the bung with a resilient force.

33 . The method of claim 31 , wherein
the drive member is rotated in increments of unit steps of movement generating a corresponding advancement of the piston rod as long as the piston rod is free to advance, and the drive member is stopped at the end of a unit step of movement that is not accompanied by a corresponding advancement of the piston rod.

34 . The method of claim 31 , wherein
a backlash between the piston rod, the drive member and the body member is determined beforehand, the drive member is rotated in increments of unit steps of movement generating a corresponding advancement of the piston rod as long as the piston rod is free to advance, and when a unit step of movement is not accompanied by a corresponding advancement of the piston rod, the drive member is further rotated until the backlash is removed.

35 . The method of claim 31 , wherein
the drive member is rotated in increments of unit steps of movement generating a corresponding advancement of the piston rod as long as the piston rod is free to advance, after an increment that is not accompanied by a corresponding advancement of the pis

Assignees

• Sanofi Aventis Deutschland

Inventors

• Plumptre David Aubrey
• Draper Paul Richard
• Mercer David Richard
• Rekaya Naceur
• Griffin Paul
• Veasey Robert

Classifications

• A61M5/31551 Primary

  including axial movement of dose setting member · CPC title

• A61M2005/31516

  reducing dead-space in the syringe barrel after delivery · CPC title

• A61M2207/00

  Methods of manufacture, assembly or production · CPC title

• A61M5/31585

  performed by axially moving actuator, e.g. an injection button · CPC title

• A61M2207/10

  Device therefor · CPC title