| 摘要 |
1495671 Loading syringes W SARSTEDT [trading as WALTER SARSTEDT KUNSTSTOFFSPRITZGUSSWERK] 2 April 1975 [2 April 1974] 13437/75 Heading A5R [Also in Division Fl] The retraction stroke of a piston and cylinder syringe 1, 2 is effected using a device to which the syringe is releasably mounted and which itself comprises a piston and cylinder 13, 14 which, when unlocked from their telescoped position, Fig. 1, by operation of pawl 20, move apart to their Fig. 3 position due to the lower pressure induced on the left hand side of the piston 13 during telescoping. An abutment 24 retracts the syringe cylinder 1 to draw in blood from a patient via a cannula (not shown) attached to mount 6. The device piston has its rod 12 screwed into a support casing such that the device cylinder 14 moves over the piston. The retraction stroke may be stopped slightly short by the engagement of pawl 20 in a second detent 17". In this way, release of the pawl from detent 17" allows completion of the stroke as determined by a stop 12' engaging cylinder plug 11 such that any small blood droplets remaining in the catheter are sucked in. In a modification Figs. 5-8 (not shown) the syringe is releasably mounted to the device by means other than co-operation of flange 5 and fingers 10. In either modification cylinder vent plug 15 may be replaced by a plug having a vent bore including a check valve, an axial air inlet bore in parallel with the vent bore, and a rotatable exterior disc having different diameter bores which can be selectively aligned with the axial bore whereby the rate of air ingress into the cylinder during its outward movement, and thereby the syringe retraction stroke speed, can be varied as desired. |
