Device for locking a flat, preferably discoid substrate onto the substrate plate of a vacuum coating apparatus

In a device for locking a flat, discoid substrate 9 provided with a central opening 38 onto a substrate plate 22 provided with a centering post 35 projecting above the substrate bearing surface 42 of a vacuum coating apparatus for transporting the substrate from one to the other treatment station and/or for putting the substrate into or taking it out of the treatment chamber or transport chamber 13, 14 through an airlock, the centering post 35 has a cross-sectional area enabling the centering post 35 to pass through the central opening 38 and it is provided with an annular groove which runs approximately at the level of the upper surface of the substrate remote from the plane of the substrate bearing surface 42, while an endless slantingly wound coil spring 37 is placed into the annular groove 40, and upon the action of a force (P) directed radially toward the spring flattens the outer torus surface enveloping the spring 39, and thus locks the substrate pushed over the spring 37 at the upper edge of the opening 38 in the manner of a snap fastener.