Double acting pneumatic serateurs.

摘要

1. Pneumatic secateurs, particularly for the work of pruning or of crop gathering in arboriculture, viticulture or horticulture, comprising a body (1) at the forward end of which are placed two blades of which one pivoting blade (6) is actuated by a pneumatic device comprising at least one driving piston (10) disposed with a capability of fluid-tight axial sliding in this body, the piston or pistons bounding, at the interior of the said body, a chamber or chambers (C3, C4) disposed in front of the piston or pistons (10, 12) and a chamber (C2) disposed behing the single piston or behing the primary piston (10), whilst the pneumatic distributor comprises : on the one hand, a fixed body or assembly (3, 29) comprising an opening permitting the establishement of a communication between the inlet (22) of compressed fluid and the chamber or chambers (C3, C4) disposed in front of the piston or pistons (10, 12), an opening permitting the placing in communication of the said compressed fluid inlet and the chamber (C2) disposed behind the single piston or behind primary piston (10), and an opening permitting the establishment of a communication between the said rear chamber and the atmosphere ; and, on the other hand, movable members disposed in alignement and constituted by : - an admission device the opposed lower and upper seats of which bound, respectively, the opening permitting the establishment of a communication between the compressed fluid inlet (22) and the chamber or chambers (C3, C4) disposed in front of the piston or pistons (10, 12), and the opening permitting the placing in communication of the said compressed fluid inlet and the chamber (C2) disposed behind the single piston or the primary piston (10) ; - an escape valve (28) the operation of which is, in part, connected to that of the admission device and controlling the opening to atmosphere of the chamber (C2) disposed behind the single piston or behind the primary piston (10) ; - and a pusher member (30) adapted to act on the said admission device ; the said pneumatic distributor comprising further means for returning of its movable members, characterized in that the admission device is constituted by a single inlet valve (27) having two opposed faces and capable of being seated either onto the lower seat bounding the opening placing into communication the inlet (22) for compressed fluid and the chamber or chambers (C3, C4) disposed in front of the driving piston or pistons (10, 12) of the movable blade, or on the upper seat bounding the opening placing into communication the said inlet of compressed fluid and the chamber (C2) disposed behind the single piston or behind the primary piston (10).