The present invention, in some embodiments thereof, relates to automatic injectors and, more particularly, but not exclusively, to force containment in automatic injectors.
U.S. Pat. Nos. 6,500,150, 6,824,529, and 6,843,782 disclose a drug delivery device having a base member defining a skin-contacting surface, a syringe serving as a reservoir for the drug, and means for expelling drug from the syringe. The syringe is connected to the base member such that the longitudinal axis of the syringe is substantially parallel to the skin surface. A delivery needle is in communication with the syringe. The needle has an angled bend which directs the tip of the needle substantially perpendicular to the skin-contacting surface. In use, the tip of the needle is adapted to penetrate the skin of the subject.
For such relatively slow release, an automatic expulsion device has also been suggested. U.S. Pat. No. 5,858,001 discloses a liquid drug delivery device adhered to the skin of a subject by a base member defining a skin-contacting surface having an adhesive coating. A columnar cartridge serves as reservoir for the drug and is incorporated in a housing which is connected to the base member such that in use the longitudinal axis of the cartridge is disposed substantially parallel to the skin-contacting surface. A delivery needle communicating in use with the interior of the cartridge penetrates the skin of the subject when the housing snaps downward relative to the base member. This action also causes the actuation of a citric acid/sodium bicarbonate gas generator which generates a gas to move a piston within the cartridge, compressing the drug compartment. This compression causes a stopper to be penetrated by a conduit in communication with the delivery needle, allowing the drug to be ejected from the compartment through the needle and into the subcutaneous tissue of the subject.
Additional background art includes U.S. Pat. No. 6,189,292. U.S. Patent Publication No. 20130253434, U.S. Patent Publication No. 2009/0093792, U.S. Pat. No. 7,967,795.