Abstract: The invention is a micro-tuning device for pianos and other keyboard-operated stringed musical instruments. A mass is secured to a single string or choir of strings in the musical instrument by an attachment device between the bridge and the agraffe, nut or V-bar, thereby reducing the speaking length and increasing the pitch of the string.

Abstract: An assembly for a combustion chamber monitoring camera comprises an image-forming optical system (20) whose object space (26) is a combustion chamber and whose image plane (5) is coincident with the photosensitive element of the camera, and whose focal point (24) on the object space side is situated outside the optical system (20), and a structure (22) enclosing the optical system (20). On the object space side of the optical system (20), a solid baffle plate (38) is placed having a hole (1) made cocentrical with the center axis of the optical system (20) and situated at the focal point (24) of the entire optical system on the object space side, or in the vicinity thereof. A structure (22,40) encloses the optical system (20) in such a manner that purging air can be fed via the hole (1) along a channel (32,34) positioned between the optical system (20) and the enclosing structure (22,40) thereof in the combustion chamber.

Abstract: An assembly for a combustion chamber monitoring camera comprises an image-forming optical system (20) whose object space (26) is a combustion chamber and whose image plane (5) is coincident with the photosensitive element of the camera, and whose focal point (24) on the object space side is situated outside the optical system (20), and a structure (22) enclosing the optical system (20). on the object space side of the optical system (20), a solid baffle plate (38) is placed having a hole (1) made cocentrical with the center axis of the optical system (20) and situated at the focal point (24) of the entire optical system on the object space side, or in the vicinity thereof, and the structure (22, 40) encloses the optical system (20) in such a manner that purging air can be fed via the hole (1) along a channel (32, 34) positioned between the optical system (20) and the enclosing structure (22, 40) thereof in the combustion chamber.