Drawing board mounted on single column - has spring connection between foot lever and clamping levers as safety device should pneumatic spring fail

摘要

The single-column drawing board has weight compensation in the form of a pneumatic spring mounted in a telescopically displaceable tube containing two parallel clamping levers mounted on either side of the tube. Movement is by a brake rod actuated by a foot lever. A non-positive connection produced by a spring is provided between the foot lever and the clamping levers which produces an effective safety device preventing the board from dropping down should the pneumatic spring fail. Only the difference between the thrust of the pneumatic spring and the weight of the actual drawing board is decisive for initiating the safety measure.