# US 10,441,722 B2 · Drug delivery device with spring mechanism

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- Number: US 10,441,722 B2
- Document ID: US10441722B2
- Status: Granted
- Kind: B2
- Application number: 15/568,574
- Filed: 2016-04-29
- Published: 2018-06-07
- Granted: 2019-10-15
- Earliest claimed: 2016-04-29
- Assignees: Novo Nordisk A/S
- Applicants: Novo Nordisk A/S
- Inventors: Ebbe Kiilerich
- Web page: https://patentgrep.com/patent/US10441722B2

## CPC

- A61M 5/31553: {without axial movement of dose setting member}
- A61M 5/20: Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically (A61M5/142 takes precedence)
- A61M 5/2033: {Spring-loaded one-shot injectors with or without automatic needle insertion (multishot dosing syringes A61M5/31525, needle insertion only A61M5/3287)}
- A61M 5/31535: {Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose}
- A61M 5/31536: {Blocking means to immobilize a selected dose, e.g. to administer equal doses}
- A61M 5/3155: {by rotational movement of dose setting member, e.g. during setting or filling of a syringe}
- A61M 5/31558: {using scaling up or down transmissions, e.g. gearbox}
- A61M 5/31575: {using scaling up or down transmissions, e.g. gearbox}
- A61M 5/3158: {the component being manually operated or triggered by an axially moving actuator operated by user, e.g. an axially movable injection button}
- A61M 5/31583: {the piston rod being moved by the rotational movement of a component directly in contact with it}
- A61M 5/31593: {Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir}
- A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)}

## Abstract

A drug delivery device comprises an housing, an axially displaceable piston rod, a rotatable drive member, a spring housing, a torsion drive spring coupled to the spring housing respectively the drive member, dose setting means allowing a user to simultaneously set a dose amount to be expelled and strain the torsion drive spring correspondingly by rotation of the drive member, and a release member being axially moveable relative to the housing between a proximal initial position and an actuated distal release position. The spring housing is helically coupled to the housing such that the spring exerts a tangential force on the spring housing to thereby bias the spring housing in the proximal direction, whereby the spring housing thereby exerts a proximally directed biasing force on the release member. The spring housing can be moved helically in the distal direction when a distally directed force is exerted on the release member.

## Claims

### Claim 1

A drug delivery device comprising or adapted to receive a drug-filled cartridge, comprising:
a housing,
an expelling assembly comprising:
a piston rod adapted to engage and axially displace a piston in a received cartridge in a distal direction to thereby expel a dose of drug from the cartridge,
a drive member defining an axis,
a spring housing,
a torsion drive spring coupled to the spring housing and respectively the drive member,
dose setting means allowing a user to simultaneously set a dose amount to be expelled and strain the drive spring correspondingly by rotation of the drive member, comprising:
a dose setting member which during dose setting is rotationally coupled to the drive member and adapted to rotate in a first direction to set a dose, and
a ratchet mechanism allowing the drive member to be held in a set rotational position against the bias of the strained torsion drive spring,
release means adapted to release the strained torsion drive spring to rotate the drive member to expel the set dose amount, the release means comprising a release member being axially moveable relative to the housing between a proximal initial position and an actuated distal release position,
wherein:
the torsion drive spring housing is helically coupled to the housing, the spring exerting a tangential force on the spring housing to thereby bias the spring housing in the proximal direction,
the spring housing exerts a proximally directed biasing force on the release member when actuated, and
the spring housing can be moved helically in the distal direction when a distally directed force is exerted on the release member.

### Claim 2 (depends on 1)

A drug delivery device as in claim 1, wherein the release member is axially fixed relative to the drive member.

### Claim 3 (depends on 1)

A drug delivery device as in claim 1, wherein the dose setting member is adapted to rotate in an opposed second direction to reduce a set dose.

### Claim 4 (depends on 3)

A drug delivery device as in claim 3, wherein the ratchet mechanism can be adjusted in both the first and the second direction.

### Claim 5 (depends on 4)

A drug delivery device as in claim 4, wherein the ratchet mechanism is in the form of a two-way ratchet mechanism allowing a set dose to be diminished.

### Claim 6 (depends on 4)

A drug delivery device as in claim 4, wherein the ratchet mechanism is in the form of a releasable one-way ratchet mechanism allowing a set dose to be diminished.

### Claim 7 (depends on 1)

A drug delivery device as in claim 1, wherein the spring housing is helically coupled to the housing by means of protrusions received in corresponding inclined slots.

### Claim 8 (depends on 7)

A drug delivery device as in claim 7, wherein the inclined slots are formed in the housing.

### Claim 9 (depends on 1)

A drug delivery device as in claim 1, wherein the spring housing is helically coupled to the housing by means of:
proximally open inclined slots extending from the housing, and
distally extending inclined fingers extending from the spring housing and adapted to slidingly engage the inclined slots.

### Claim 10 (depends on 1)

A drug delivery device as in claim 1, wherein the torsion drive spring is pre-strained.