Parking valve for manual operation of a spring-loaded trailer parking brake

The parking valve (1) has a housing (2) with connections (29, 30) for lines (12, 31) and a venting connection (32). A push rod (16) slide is in the housing. A power sole in the form of a friction member (20) acting with a counter-surface (21) has to be overcome for manual operation, moving between its two end positions.