US3572920A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Projector for photographic transparencies
Assignee: Robert Bosch Elektronik und Photokino GmbH
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Filing: 1969-09-19
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Granted: 1971-03-30
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Expires: 1989-09-19
Abstract
Abstract A slide projector wherein the slide changer is reciprocable between two end positions and through a median position in which a slide which is transported by the slide changer from the tray to projection position begins to open a diaphragm. The drive for the slide changer comprises a disengageable coupling which yields when the slide changer offers excessive resistance to movement in a direction to place a slide into projection position. A manually operable blocking device intercepts the slide changer before the latter reaches its median position so that the coupling is then disengaged and the slide which is pushed by the slide changer cannot reach its projection position and cannot open the diaphragm.
Inventors
- 👤 Rolf Heinzmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:46
CPC Classifications
G; G03; G03B; G03B23/00; G03B23/02; G03B23/04; G03B23/046
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
170 words
In a slide projector, a combination comprising a slide changer movable between two end positions and through a median position; drive means for moving said slide changer and including a yieldable coupling which normally drives the slide changer during movement from one to the other end position but can yield if said slide changer is blocked; diaphragm means movable from a normal sealing position in which it prevents projection light from reaching the screen to an open position; motion transmitting means operative to move said diaphragm means from said sealing position to said open position during movement of said slide changer from said median to said other end position; and blocking means including a blocking member movable by hand to an operative position in which the blocking member intercepts said slide changer while the latter receives motion from said coupling and before the slide changer moves beyond said median position so that said coupling yields and the diaphragm means remains in its sealing position while the changing cycle is completed.
Claim 2
Dependent Claim
170 words
In a slide projector, a combination comprising a slide changer movable between two end positions and through a median position; drive means for moving said slide changer and including a yieldable coupling which normally drives the slide changer during movement from one to the other end position but can yield if said slide changer is blocked; diaphragm means movable from a normal sealing position in which it prevents projection light from reaching the screen to an open position; motion transmitting means operative to move said diaphragm means from said sealing position to said open position during movement of said slide changer from said median to said other end position; and blocking means including a blocking member movable by hand to an operative position in which the blocking member intercepts said slide changer while the latter receives motion from said coupling and before the slide changer moves beyond said median position so that said coupling yields and the diaphragm means remains in its sealing position while the changing cycle is completed.
Claim 3
Dependent Claim
25 words
A combination as defined in claim 1, wherein said blocking means further comprises detent means for releasably holding said blocking member in its operative position.
Claim 4
Dependent Claim
34 words
A combination as defined in claim 2, wherein said blocking means further comprises release means for rendering said detent means ineffective in response to movement of said slide changer from said one end position.
Claim 5
Dependent Claim
43 words
A combination as defined in claim 3, wherein said release means comprises a retaining member operative to engage said blocking member in response to movement of said slide changer from said one end position to thereby retain the blocking member in operative position.
Claim 6
Dependent Claim
45 words
A combination as defined in claim 4, wherein said blocking means further comprises resilient means arranged to move said blocking member away from operative posItion when said detent means is ineffective and in response to movement of said slide changer to said one end position.
Claim 7
Dependent Claim
44 words
A combination as defined in claim 2, wherein said detent means comprises a sleeve reciprocably accommodating said blocking member and a detent spring provided on said blocking member and engaging said sleeve in response to movement of the blocking member to its operative position.
Claim 8
Dependent Claim
27 words
A combination as defined in claim 6, wherein said blocking means further comprises a return spring arranged to bias said blocking member away from said operative position.
Claim 9
Dependent Claim
46 words
A combination as defined in claim 7, wherein said blocking means further comprises a release lever pivotally mounted on said slide changer and arranged to engage said blocking member when it is in its operative position while said slide changer moves from said one end position.
Claim 10
Dependent Claim
47 words
A combination as defined in claim 8, wherein said release lever comprises a projection and said blocking member is provided with a notch which receives said projection during movement of the slide changer from said one end position when said blocking member is in its operative position.
Claim 11
Dependent Claim
46 words
A combination as defined in claim 9, wherein said projection is arranged to disengage said detent spring from said sleeve in response to entry into said notch so that said lever thereupon holds the blocking member in operative position against the opposition of said return spring.
Claim 12
Dependent Claim
47 words
A combination as defined in claim 8, wherein said release lever is yieldably mounted on said slide changer so that it can bypass said blocking member during movement of the slide changer to said one end position and while said blocking member dwells in its operative position.
References Cited (Backward Citations)
US2949814A
Cited
US2979987A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-29 | 1974-09-28 | 1975-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-29 | 1978-09-28 | 1979-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-29 | 1982-09-28 | 1983-03-30 | $7700.00 | Window Closed / Lapsed |