Patent ID: 7926412

Claim:
A retractable assembly, comprising: an assembly housing formed by a cylinder; a linear drive mounted in said assembly housing; and a tubular holder, movably guided between a measuring position and a service position by means of said linear drive, for fluid-sealed reception of a sensor, with which a physical and/or chemical process variable is determinable, wherein: said linear drive includes a piston seated movably in said cylinder and loadable with a pressure-bearing medium on one or both ends; said tubular holder is fixed in said piston; an electrode shaft of the sensor is sealed in the piston by means of an O-ring; said piston has on its working end active for the measuring position a breach in the direction of the interior of said tubular holder; and said breach comprises four traversing bores arranged uniformly distributed around the periphery, via which bores the pressure chamber is connected with a sensor receiving space inside the tubular holder.