Injection device with compression spring for engaging ratchet elements, for biasing an actuation button, and for biasing a locking element into a dose setting mode

Abstract

The present invention is generally directed to an injection device for selecting and dispensing a number of user variable doses of a medicament. The injection device comprises a housing () having a longitudinal axis (I), a dose setting member () rotatable relative to the housing () during dose setting, a drive member () which is rotationally constrained to the housing () in a first dose setting mode and which is rotatable relative to the housing () in a second dose dispensing mode, a locking element () which is permanently rotationally constrained to the housing () and movable relative to the housing () in a direction parallel to the longitudinal axis (I) between a first dose setting position and a second dose dispensing position, an actuation button () movable relative to the housing () in a direction parallel to the longitudinal axis (I) between a first dose setting position and a second dose dispensing position for switching the injection device between the first dose setting mode and the second dose dispensing mode, a ratchet () for transmitting torque from the dose setting member () to the drive member () during dose dispensing and allowing relative rotational movement between the dose setting member () and the drive member () during dose setting, the ratchet () comprising first ratchet features () rotationally constrained to the driver () and second ratchet features () rotationally constrained to the dose setting member (), and a spring (). The spring () biases the locking element () and the actuation button () into their first dose setting position and biases the first ratchet features () into engagement with the second ratchet features ().