Syringe with dose metering device
AssigneesRobert Charles Turner, Rury Reginald Holman, Owen Mumford Limited
InventorsRury R. Holman, Jeremy M. J. Marshall
Life of this patent
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Abstract
A generally pen-like syringe incorporates a dose metering device provided by a cap 7 rotatable with respect to a pen body 8 to a position related to the dose of medicament (for example insulin) to be injected. The rotation compresses a coil spring 6, which is prevented from unwinding by cooperating ratchet teeth. When the dose is to be injected, a trigger slide 42 is moved to the left causing the ratchet teeth to come out of engagement. This permits the spring 6 to unwind, thereby rotating a drive sleeve 1, drive gear 3 and a drive plunger 2. The drive plunger 2 is formed with a quick pitch screw thread so that its rotational movement is accompanied by axial movement to cause medicament to be discharged from a cartridge and injected through a needle.
Claims8
A syringe for injecting a set dose comprising:
- a body;
- a spring on the body;
- a dose-setting device mounted on the body and connected to the spring, the dose-setting device being moveable to a selected set position against the bias of the spring, wherein movement of the dose-setting device to the selected position is accompanied by straining of the spring;
- a latch on the body arranged to retain the dose-setting device in the set position against the bias of the spring;
- and
- a latch release means on the body to release the latch to cause the set dose to be expelled from the syringe, the force for expelling the set dose being provided by the spring.
Dependencies are inferred from the claim text.