Delay mechanism for automatic injection device

Abstract

A delay mechanism for staging the operation of an automatic injection apparatus (20) to ensure medication contents are properly delivered prior to the needled syringe (32) of the apparatus being retracted. In one form, the delay mechanism includes a shuttle (50), a follower (110), a locking member, a damping compound, and a driver and a driver biasing element (44). The shuttle is for a needled syringe of the apparatus and includes a first latching element. The follower includes a second latching element and a cammable surface, which second latching element is for cooperating with the first latching element to limit motion of the shuttle relative to the follower in a second direction opposite the first direction. The locking member is movable from a locking position to a release position by engagement with the syringe plunger during an injection, the locking member, when in the locking position, preventing rotation of the follower relative to the shuttle, the locking member, when in the release position, allowing rotation of the follower relative to the shuttle. The damping compound is between the follower and a supporting surface to dampen rotation of the follower relative to the shuttle. The driver is rotatably fixed relative to the shuttle and includes a camming surface. The shuttle allowing retracting of the syringe needle into the housing of the automatic injection apparatus after injection.

Description

technical field

[0001] The present invention relates to drug injection devices, and more particularly to a delay mechanism for an automatic injection device. Background technique

[0002] Patients with many different diseases often have to self-inject the drug. Various devices have been developed to assist in these injections. One type of device is an automatic injection device. Devices of this type, when triggered by the user, cause the needle of the syringe provided in the housing of the device before triggering to be automatically inserted into the user's body and thereafter to automatically inject a dose of medicament through the inserted needle. Automatic injection devices of known type then automatically advance the shroud to cover the needle when the dose has been administered. In another type of automatic injection device, there is a more satisfactory configuration for some applications, wherein instead of an advancing shroud, the device will automatically retract...

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