US3874792A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lamp housing for use in photographic enlargers or the like
Assignee: Agfa Gevaert AG
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Filing: 1973-08-01
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Granted: 1975-04-01
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Expires: 1993-08-01
Abstract
Abstract A convertible light confining device for use in lamp housings of photographic projection printers resembles a hollow truncated pyramid through which the light passes in a direction from the top plane toward the base plate or vice versa. The sides of the truncated pyramid have rectangular or trapezoidal central portions which are pivotable inwardly about axes located in the top plane to form a second light duct of constant cross-sectional area or a second light duct which resembles a hollow truncated pyramid having a base plane coinciding with the top plane of the first truncated pyramid and a top plane which is smaller than but coplanar with the base plate of the first pyramid.
Inventors
- 👤 James Turner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:56
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/32; G03B27/52; G03B27/54; G03B27/545
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
146 words
In a lamp housing, particularly for use in photographic projection printers, a light confining and guiding device comprising a plurality of walls movable between first positions in which said device constitutes a first light duct in the form of a first hollow truncated pyramid with spaced apart top and base planes and contiguous sides which confine light that enters said first duct by passing across one of said planes and issues from said first duct by passing across the other of said planes, and at least one second position in which said device constitutes a different second light duct having the form of a second hollow truncated pyramid with spaced apart top and base planes and contiguous sides the area of at least one of said planes of said second pyramid being different in size from the area of the corresponding plane of said first pyramid.
Claim 2
Dependent Claim
146 words
In a lamp housing, particularly for use in photographic projection printers, a light confining and guiding device comprising a plurality of walls movable between first positions in which said device constitutes a first light duct in the form of a first hollow truncated pyramid with spaced apart top and base planes and contiguous sides which confine light that enters said first duct by passing across one of said planes and issues from said first duct by passing across the other of said planes, and at least one second position in which said device constitutes a different second light duct having the form of a second hollow truncated pyramid with spaced apart top and base planes and contiguous sides the area of at least one of said planes of said second pyramid being different in size from the area of the corresponding plane of said first pyramid.
Claim 3
Dependent Claim
38 words
A light confining device as defined in claim 1, wherein the length of said first light duct, as considered in the direction of the passage of light therethrough, is identical with the length of said second light duct.
Claim 4
Dependent Claim
27 words
A light confining device as defined in claim 1, wherein one of said light ducts is located within the confines of the other of said light ducts.
Claim 5
Dependent Claim
35 words
A light confining device as defined in claim 1, wherein said second light duct has a first open end in one of said planes and a second open end in the other of said planes.
Claim 6
Dependent Claim
41 words
A light confining device as defined in claim 4, wherein the area of said first end is identical with the area of said one plane and the area of said second end is different from the area of said other plane.
Claim 7
Dependent Claim
22 words
A light confining device as defined in claim 1, wherein said walls constitute portions of the sides of said first light duct.
Claim 8
Dependent Claim
32 words
A light confining device as defined in claim 6, wherein said walls are pivotable between said first and second positions about axes which are located in the region of said top plane.
Claim 9
Dependent Claim
30 words
A light confining device as defined in claim 7, wherein said walls are further movable at right angles to the respective axes in the course of said pivotal movement thereof.
Claim 10
Dependent Claim
32 words
A light confining device as defined in claim 7, wherein each side of said first light duct further comprises corner portions flanking the respective wall in the first position of such wall.
Claim 11
Dependent Claim
20 words
A light confining device as defined in claim 9, further comprising a frame which is rigid with said corner portions.
Claim 12
Dependent Claim
45 words
A light confining device as defined in claim 9, wherein said walls make with said base plane a first angle in said first positions thereof and a second angle in said second positions thereof, said second angle being at least equal to said first angle.
Claim 13
Dependent Claim
57 words
A light confining device as defined in claim 11, wherein said second angle is greater than said first angle and each side of said first light duct further comprises a sill adjacent to said base plane, extending between the respective corner portions and being flush with the respective wall in said first position of the respective wall.
Claim 14
Dependent Claim
30 words
A light confining device as defined in claim 1, wherein said walls are rectangular and the cross-sectional area of said second light duct is substantially constant from end to end.
Claim 15
Dependent Claim
23 words
A light confining device as defined in claim 1, further comprising means for simultaneously moving said walls between said first and second positions.
Claim 16
Dependent Claim
28 words
A light confining device as defined in claim 14, wherein said means for moving comprises means for biasing each of said walls to one of said positions thereof.
Claim 17
Dependent Claim
32 words
A light confining device as defined in claim 14, wherein said means for moving comprises followers provided on said walls and means for moving said walls by way of the respective followers.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |