Optical instrument including a focusing eyepiece and an endoscope

Claim 1

An optical instrument comprising, in combination, a focusing eyepiece and an endoscope coupled therewith, the eyepiece comprising: a cylindrical body, a first support carrying a first lens sealed to one end of the cylindrical body nearest the endoscope, an external sleeve rotatably and slidably mounted on the cylindrical body so as to surround said body, said sleeve having a second support carrying a second lens which is in axial alignment with the first lens and being sealed to one end of the sleeve so that the sleeve and the second support form a cap that closes off the open end of the cylindrical body furthest from the endoscope, means for causing sliding axial movement of the sleeve relative to the cylindrical body during rotation of the sleeve thereby to adjust the relative spacing between the first and second lenses for focusing said instrument, an annular seal located between the cylindrical body and the sleeve that permits the sleeve to rotate and slide axially relative to the cylindrical body while maintaining a sealing relationship between them, and a complementary assembly means for coupling the eyepiece and the endoscope together, said complementary assembly means comprising a cylindrical skirt that extends radially outward from the first support and co-axially with the endoscope and containing a first portion having a first inner diameter and a second portion, aligned with said first portion, and having a second inner diameter larger than said first inner diameter and being located closer to the end of the eyepiece to be coupled to the endoscope than said first portion, said skirt mating with a cylindrical collar projecting outwardly from the end of the endoscope to be coupled to the eyepiece, the outer diameter of the cylindrical collar being substantially equal to the inner diameter of the skirt to provide a relatively tight fit with a resilient annular seal between the collar and the skirt that allows separation of the eyepiece and the endoscope only by relative axial movement between them while maintaining a sealing relationship between them when they are coupled together.