(57) The invention provides a positioner by which a member (1), which may be massive and,
for instance, a part of a valve, may be moved to a pre-determined position. The movement
of the member (1) is controlled by a pneumatic valve (2) that is connected to a lever
(14). The lever (14) is pivoted at two locations (13a and 20) which can both be moved
transversely to the lever (14). By moving the first location (13a) the pneumatic valve
(2) is open to move the member (1) and movement of the member (1) moves the second
location (20) to tilt the lever 14 back to a position in which the pneumatic valve
(2) is again closed.
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