GB2452030A — Injection devices

USPTO Abstract

An injection device has a main drive module which can screwed into the back of a syringe housing 12 to prepare the injector ready for use. The drive module has a firing button and a drive plunger released for forward movement by pressing the firing button. The syringe housing slideably receives a syringe holder 36 whose forward movement is initially prevented by internally directed barbs 46 on a cylindrical latching sleeve 42. The latching sleeve is acted upon by a release ring 50 on the drive module such that as the drive module is screwed onto the syringe housing, the release ring splays the cylindrical shell to release the syringe carrier for forward movement. The barbs 46 also act as a latch to latch the syringe carrier in its rearward position when the drive module is unscrewed from the syringe housing, which returns the barbs 46 to their initial position before the syringe holder returns to its initial position.