A needlestick prevention device for an injection device (1) having a hollow needle (2) comprises a sheath having a first member (9) for attachment to the injection device (1) and a second member (10) slidable longitudinally relative to the first member (9) to expose or to cover the needle (2), and spring means (11) biasing the second member (10) to cover the needle (2). The first and second members (9, 10) have interengaging guide means (13) and locking means (14), including a first guide part (23) operative to allow free longitudinal sliding movement of the second member (10) relative to the first member (9), and a second guide part (24) operative on movement by manual relative rotation of the first and second members (9, 10) and following release of a force urging the second member (10) to expose the needle (2). The spring means (11) urges the second member (10) to cover the needle (2) and to operate the locking means (14) to retain the second member (10) covering the needle (2). This allows free movement of the second member (10) in the first guide part (23), allowing for filling of the syringe (1), but then automatic sheathing and locking when the user simply twists the second member (10) relative to the first (9).
展开▼
