US3722390A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Extension tube for photographic lenses
Assignee: Ernst Leitz Wetzlar GmbH
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Filing: 1972-02-15
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Granted: 1973-03-27
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Expires: 1992-02-15
Abstract
Abstract An extension tube for a photographic lens having a diaphragm preselection ring and a diaphragm blade ring resiliently urged into the position of the smallest diaphragm aperture. The tube is provided with a preselection ring and with an inner ring of its own. Interengaging means on the lens and on the extension tube keep the lens preselection ring arrested in its position of the smallest diaphragm aperture when the lens is mounted on the extension tube. The extension tube inner ring is provided with a first stud on its front and with a second stud on its rear, both studs extending in axial direction. The front stud engages the lens diaphragm blade ring and the rear stud engages the camera diaphragm lever so that the action of the camera diaphragm lever is transmitted through the extension tube to the lens diaphragm blade ring and the diaphragm preselection operation of the lens is maintained when the extension tube is inserted between the lens and the camera body.
Inventors
- 👤 W Schlapp
- 👤 O Boss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:52
CPC Classifications
G; G03; G03B; G03B9/00; G03B9/02; G03B9/07; G03B17/00; G03B17/02; G03B17/12; G03B17/14
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
303 words
An extension tube for photographic lenses with a diaphragm preselection ring and a spring loaded rotatable lens diaphragm blade ring which is resiliently urged against an abutting surface projecting from the preselection ring, and with a bayonet ring for coupling the lenses to SLR camera bodies which include a diaphragm lever arm, the exTension tube comprising: a. a tube body; b. bayonet socket (8) on the front surface of the tube body for coupling the lens to the extension tube and a positive bayonet ring (7) on the rear surface for coupling the extension tube to the camera body; c. a diaphragm preselection ring (6a) rotatable on the tube body and being provided with a scale of f-stop numbers on its outer surface to anyone of which the preselection ring may be set relative to an index mark on the tube body, said preselection ring also being provided with a stop member (6c) projecting from its inner surface; d. an inner ring (11) rotatable within the tube body and being provided with a first lug extending in axial direction to the front (14) and with a second lug extending in axial direction to the rear (13), the first lug engaging the lens diaphragm blade ring when the photographic lens is mounted in the extension tube and the second lug engaging the diaphragm lever arm when the extension tube is mounted to the camera body; and e. spring means (12) urging the inner ring in an abutting contact with the stop member of the preselection ring so that the inner ring will be rotated against the stop member upon withdrawal of the diaphragm lever arm from engagement with the second lug, thereby also rotating the first lug so that the lens diaphragm blade ring can follow this first lug under its own spring load.
Claim 2
Dependent Claim
303 words
An extension tube for photographic lenses with a diaphragm preselection ring and a spring loaded rotatable lens diaphragm blade ring which is resiliently urged against an abutting surface projecting from the preselection ring, and with a bayonet ring for coupling the lenses to SLR camera bodies which include a diaphragm lever arm, the exTension tube comprising: a. a tube body; b. bayonet socket (8) on the front surface of the tube body for coupling the lens to the extension tube and a positive bayonet ring (7) on the rear surface for coupling the extension tube to the camera body; c. a diaphragm preselection ring (6a) rotatable on the tube body and being provided with a scale of f-stop numbers on its outer surface to anyone of which the preselection ring may be set relative to an index mark on the tube body, said preselection ring also being provided with a stop member (6c) projecting from its inner surface; d. an inner ring (11) rotatable within the tube body and being provided with a first lug extending in axial direction to the front (14) and with a second lug extending in axial direction to the rear (13), the first lug engaging the lens diaphragm blade ring when the photographic lens is mounted in the extension tube and the second lug engaging the diaphragm lever arm when the extension tube is mounted to the camera body; and e. spring means (12) urging the inner ring in an abutting contact with the stop member of the preselection ring so that the inner ring will be rotated against the stop member upon withdrawal of the diaphragm lever arm from engagement with the second lug, thereby also rotating the first lug so that the lens diaphragm blade ring can follow this first lug under its own spring load.
Claim 3
Dependent Claim
74 words
An extension tube as claimed in claim 1, and further comprising a groove (9) in the front surface of the tube body for accepting a pin (4a) of the lens preselection ring, the groove being so positioned on the circumference of the front surface that the lens can only be properly mounted in the extension tube when the lens preselection ring has been set to a position which corresponds to the smallest diaphragm aperture.
Claim 4
Dependent Claim
51 words
An extension tube as claimed in claim 1, and further comprising an annular shoulder (6b) projecting from the outer circumference of the front surface of the extension tube in forward direction for covering the lens preselection ring along all of its circumference when the lens is mounted in the extension tube.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |