Abstract: A frame structure consisting of two compound units provided with mutually facing grooves undercut on either side, in which the first compound unit can be attached in a desired position to the second compound unit via a detachable coupling which comprises a turning part which can be turned from the outside manually via a handle about its longitudinal axis by about 90.degree. into its coupling or decoupling position, and which in its coupling position positively engages by means of a T-head at its one end in one of the two grooves and by means of anchoring means at its other end in the other of the two grooves and can be locked in this coupling position by means of an anti-rotation device.

Abstract: In a selective control device for plural kinds of oil-hydraulic actuators comprising an actuator selective valve for selecting an operative oil-hydraulic actuator from among plural kinds of oil-hydraulic actuators and a directional control valve for operating the selected actuator extendedly and retractedly, the actuator selective valve is provided with a quick extensional position which functions to connect an extensional pressure port thereof to a bottom side oil chamber of the selected actuator and also to connect a head side oil chamber to the bottom side oil chamber in order to extend the selected actuator quickly. The construction of the actuator selective valve eliminates a quick extensional valve adopted in a prior oil-hydraulic control device.