The invention relates to an injection device comprising an elongate housing and a cap removably mounted over a forward end of the housing. The cap comprising at least one slot extending forwardly from its rear edge the at least one slot being configured to engage with an outwardly projecting protrusion on an outer surface of the housing when the cap is mounted on the housing. A rearward portion of the cap includes rearwardly extending engagement features provided on each side of the at least one slot, the engagement features being configured to locate within a cavity in the housing when the cap is mounted on the housing. The cavity is provided with corresponding surfaces which align with the cap engagement features so as to hold the outwardly projecting protrusion within the cut-out.本發明係關於一種注射裝置,包含一狹長殼體及一蓋體,該蓋體可移除地安裝於該殼體的一前端。該蓋體包含自其後邊緣向前延伸的至少一狹長孔;該狹長孔係配置成當該蓋體係安裝於該殼體上時與該殼體的一外表面上的一向外凸出凸件接合。該狹長孔的一後部包括向後延伸接合特徵,係提供於該狹長孔的每一側上,當該蓋體係安裝於該殼體上時,該等接合特徵係配置位於該殼體的一腔體內。該腔體係具有與該蓋體的接合特徵對齊的對應表面,以將向外凸出凸件固定於該切口內。1‧‧‧注射器裝置10‧‧‧殼體12‧‧‧後本體部12a‧‧‧後部13‧‧‧鄰接面16‧‧‧蓋體16a‧‧‧握面17‧‧‧後邊緣18‧‧‧觸發按鈕20‧‧‧觀察窗22‧‧‧切口24‧‧‧切口
