Abstract: A check valve with a valve seat formed in the valve housing wherein two side-by-side locking members are pivotably mounted in the valve seat for movement between an open and closed position. The locking members have their pivoting edges mounted adjacent and parallel to each other in the housing and have bearing bushings formed along the adjacent edges which engage side-by-side shafts whose ends are engaged to the valve housing. A pair of locking springs each have their windings engaged to one of the shafts which are located between the bearing bushings. Each of said springs has a first shank portion which is rigidly supported by an abutment of the valve housing and a second shank portion which engages the locking member mounted on the same shaft of the corresponding spring to urge the same into a closed position relative to the valve seat.

Abstract: A flap valve is provided which includes a valve housing having a valve seat defined therein, on one side of which is a flow inlet chamber and on the other side of which is a flow discharge chamber, at least one locking element pivotably mounted in the valve housing for movement between an open and closed position relative to the valve seat, and at least one locking spring mounted in the flow inlet chamber of the housing having one portion which is rigidly held in the valve housing and a pivotable lever arm which engages the locking element to urge the locking member into the closed position. The lever arm of the spring and the locking member are slideably coupled together so that the force required to open the locking member increases only slightly or preferably decreases during the opening pivotable movement of the locking member.

Abstract: In an oil spraying device for the delivery of oil admixed with compressed air, a connection means is provided to connect the ends of a spring which contacts the control flap to vary the torque imparted to the control flap. For this purpose, the spring ends are loosely coupled with the control flap and the housing so that the length of the spring arms effecting control may be varied to vary its lever action. The spring is also mounted outside the pivot axis of the control flap.

Abstract: A check valve controlled by the medium passing through comprising: a housing having an input opening on one side defining a valve seat and an output opening communicative with the input opening, a locking member disposed over the input opening of the valve seat and positioned on the seat, the locking member having a pivot axis at one end, a bearing cap mounted in and engaging the walls of the discharge opening, the cap having a pair of bearing side plates formed at one end, the side plates having laterial recesses formed therein for receiving the pivot axis of the locking member. There is also a spring coupled to the housing for urging the locking member against the valve seat.

Abstract: A flap valve, in particular a check valve comprising a valve housing and a valve seat formed therein, a plate-like locking member cooperating with the valve seat, the locking member being pivotably mounted to the housing, a locking spring extending across a remote front face and having a longitudinal axis substantially crosswise with respect to the pivot direction of the locking member. The locking spring is held axially pretensioned with one end on the valve housing and with another end on the locking member and the locking spring has the form of a leg spring and at least one winding connecting the legs. The windings are mounted substantially parallel to the front face of the locking member.