Device for rapidly changing objectives with the aid of threaded fastening

1. Device for removably fitting an objective with an external thread on a corresponding internal thread of an optical instrument, comprising an instrument adaptor having at one end an external thread corresponding to the external thread of the objective, and at an other end, a bayonet mount for fixably holding a bayonet base, and further comprising an objective adaptor which has at one end a bayonet base to be connected to the bayonet mount of the instrument adaptor, and at an other end an internal thread corresponding to the internal thread of the optical instrument, wherein the instrument adaptor comprises a mounting ring having the external thread, and a coupling ring having the bayonet mount, the mounting ring and coupling ring being rotatable relative to one another about a longitudinal axis of the instrument adaptor and being fixable in any selectable position relative to one another.

2. Device according to claim 1 , wherein, on a side opposite the external thread, the mounting ring has a mount for rotatably and fixably holding a base, and on a side opposite the bayonet mount, the coupling ring has a base which can be inserted into the mount of the mounting ring and can be locked in a longitudinal direction of the instrument adaptor.

3. Device according to claim 2 , wherein the base of the coupling ring has a circumferential groove, and the mount of the mounting ring has at least one fixing element to be brought into engagement with the circumferential groove.

4. Device according to claim 3 , wherein the bayonet base is formed by a conical outside surface of the objective adaptor which is flattened by two diametrically opposite, mutually parallel flat surfaces, and the bayonet mount is formed by a conical inside surface corresponding to the conical outside surface of the objective adaptor, of the instrument adaptor or of the coupling ring of the instrument adaptor, the conical inside surface having at least one location an interruption with a clear distance which corresponds to spacing of the flat surfaces of the objective adaptor such that the bayonet base can be pushed laterally through the interruption into the bayonet mount and can be locked in the longitudinal direction by rotation.

5. Device according to claim 4 , wherein, at two diametrically opposite locations, the conical inside surface has similar interruptions such that the bayonet base is adapted to be pushed longitudinally into the bayonet mount and locked in the longitudinal direction by rotation.

6. Device according to claim 1 , wherein the bayonet mount has at least one fixing element which can be brought into engagement with the bayonet base.

7. Device according to claim 1 , wherein, on a side opposite the internal thread, the objective adaptor has an external thread overtopping the bayonet base and corresponding to the external thread of the objective.