DEVICE INDICATOR OF THE GRADE OF OBSTRUCTION OF FILTERS FOR ADMISSION AIR

摘要

1. Indicating apparatus (10) for indicating the degree of dirt in suction air filters, including a cup-shaped housing (11), which is sealed at the open end face (14) by a cover (15) provided with viewing windows (16), a piston (25) which is sealed from the housing wall (20) by a diaphragm (21) and is displaceable from a position of rest to an indicating position in a direction opposite the force of a resetting spring (67) as a result of the difference in pressure in front of and behind the filter, and an angle lever in an indicating chamber (46) for transmitting the piston movement to an indicating disc (70), which is rotatable behind the viewing windows (16) and is mounted in an axis-parallel manner relative to the piston axis (26), wherein the angle lever is disposed with its pivotal axis extending transversely relative to the piston axis (26) and is pivotably mounted, via journals (51; 52), in an insert sleeve (29), which is secured in the housing, and wherein its first lever arm (53) acts on the indicating disc (70), and its second lever arm (60) is brought into abutment with the end face (27) of the piston facing said arm in each operating position by means of a recoil spring (64), characterised in that the piston (25) divides the interior of the housing (11) into a low-pressure vacuum chamber (45), which is situated adjacent to the housing base (12) and is provided with a connecting aperture (13) for connection with the filtered air chamber of the suction air filter, and the indicating chamber (46), and in that the angle lever is a U-shaped rocker (47), which includes a cross-piece member (50) extending parallel to the pivotal axis of said rocker, two flanges (48, 49) which are connected to the journals (51, 52) and form the second lever arm (60), and a notched projection (56) which is spaced from the pivotal axis, and in that a lock pawl (90) is provided, which is pivotably mounted in the insert sleeve (29) in an axis-parallel manner relative to the pivotal axis of the rocker (47) and engages behind the notched projection (56) in order to prevent the rocker (47) moving back from the indicating position to the position of rest.