US3811151A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Joint for collapsible ladders
Assignee: Zarges Leichtbau GmbH
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Filing: 1973-04-11
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Granted: 1974-05-21
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Expires: 1993-04-11
Abstract
Abstract A joint for collapsible ladders, wherein two members are pivotally connected to each by means of a hinge pin. Each member has a flange portion, through which the hinge pin extends, and a shaft portion adapted to be connected to the ladder stringer. A locking member comprising at least two parts adapted to be moved from a first locking position onto a second locking position and viceversa for locking the two members in at least two predetermined angular positions relating to each other. Biasing means connected to the two part of the locking member, which may be telescopically extended, for urging the locking member into one of the locking positions. The locking member being guidingly mounted on the hinge pin and includes a projecting portion which extends through an opening in the flange portion of each member when the locking member is in a locking position. Each flange portion having at least two openings each one of which is adapted to be aligned with a mating opening of the other flange portion when the ladder stringers are in a predetermined angular position to receive the projecting portion of the locking member and thereby lock the two ladder stringers in a predetermined angular position relative to each other.
Inventors
- 👤 W Kuemmerlin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:32
CPC Classifications
E; E06; E06C; E06C1/00; E06C1/02; E06C1/32; Y; Y10; Y10T; Y10T403/00; Y10T403/32; Y10T403/32254; Y10T403/32262; Y10T403/32319; Y10T403/32327
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
214 words
A joint for collapsible ladders, comprising in combination; two members each of which has a flange portion and a shaft portion; a hinge pin extending at least partially through said flange portion of each member for forming a pivotal connection between said two members; said shaft portion of each member being adapted to be connected to a ladder stringer of the collapsible ladder; a locking member comprising at least one locking rod portion and one guide rod portion which are parallel and which are adapted to be moved from a locking position to a non-locking position and vice-versa; said ladder stringers and two members being swingable about said hinge pin relative to each other when said locking member is in a non-locking position; said guide rod portion being guidingly axially movable in said hinge pin from said locking to said non-locking position and vice-versa; biasing members operatively connected to said guide rod portion for urging it into said locking position; said flange portion of each member having at least two openings each of which is adapted to be aligned with a mating opening in the other flange portion and said locking rod portion being adapted to pass through said openings to lock said two members in a predetermined angular position relative to each other.
Claim 2
Dependent Claim
214 words
A joint for collapsible ladders, comprising in combination; two members each of which has a flange portion and a shaft portion; a hinge pin extending at least partially through said flange portion of each member for forming a pivotal connection between said two members; said shaft portion of each member being adapted to be connected to a ladder stringer of the collapsible ladder; a locking member comprising at least one locking rod portion and one guide rod portion which are parallel and which are adapted to be moved from a locking position to a non-locking position and vice-versa; said ladder stringers and two members being swingable about said hinge pin relative to each other when said locking member is in a non-locking position; said guide rod portion being guidingly axially movable in said hinge pin from said locking to said non-locking position and vice-versa; biasing members operatively connected to said guide rod portion for urging it into said locking position; said flange portion of each member having at least two openings each of which is adapted to be aligned with a mating opening in the other flange portion and said locking rod portion being adapted to pass through said openings to lock said two members in a predetermined angular position relative to each other.
Claim 3
Dependent Claim
32 words
The joint for collapsible ladders as set forth in claim 1, wherein said hinge pin is hollow and has a central bore in which said guide rod portion is axially slidably movable.
Claim 4
Dependent Claim
39 words
The joint for collapsible ladders as set forth in claim 2, wherein said locking member includes two locking rod portions which are parallel to said guide rod portion and are connected to it by a manually adjustable yoke member.
Claim 5
Dependent Claim
67 words
The joint for collapsible ladders as set forth in claim 3, wherein both of said locking rod portions are equally radially spaced from said hinge pin but have different cross-sectional areas and said openings in said flange portions having corresponding different cross-sectional areas so that an alignment of openings of the same size in said flange portions permits the passage of a mating guide rod portion therethrough.
Claim 6
Dependent Claim
53 words
The joint for collapsible ladders as set forth in claim 4, wherein said locking rod portions are round anD have different diameters and the openings in the flange portions have a width in the radial direction relative to said hinge pin which substantially corresponds to the diameter of the coacting locking rod portion.
Claim 7
Dependent Claim
26 words
The joint for collapsible ladders as set forth in claim 3, wherein said two locking rod portions are differently radially spaced relative to said hinge pin.
Claim 8
Dependent Claim
50 words
The joint for collapsible ladders as set forth in claim 6, wherein both locking rod portions are formed as round-shaped rods of equal diameter, and said openings in said flange portions have a width in the radial direction which corresponds substantially to the diameter of the coacting locking rod portion.
Claim 9
Dependent Claim
48 words
The joint for collapsible ladders as set forth in claim 2, wherein said biasing means is formed as a coil spring, said guide rod portion defining an annular space within said central bore of said hinge pin, and said coil spring being axially disposed within said annular space.
Claim 10
Dependent Claim
83 words
The joint for collapsible ladders as set forth in claim 8, including at least one bushing slidably axially mounted within said central bore in said annular space, and a second coil spring coaxially mounted between said guide rod portion and said bushing, said coil spring abutting with one end against said hinge pin and with the other end against said bushing and said second coil spring abutting with one end against said bushing and with the other end against said guide rod portion.
Claim 11
Dependent Claim
27 words
The joint for collapsible ladders as set forth in claim 9, wherein said hinge pin, said guide rod portion and said bushing have substantially equal axial lengths.
Claim 12
Dependent Claim
132 words
The joint for collapsible ladders as set forth in claim 10, wherein said rod portion has at its free end a radially outward projecting first collar, said hinge pin has, at the end distance from said first collar when the locking member is in the locking position, a second radially inwardly projecting collar, and the bushing has, at the end adjacent to the first collar of the guide rod portion when the locking member is in the locking position, a third radially outward projecting collar and at the other end a fourth radially inward projecting collar, whereby the outer diameter of the first collar is larger than the inner diameter of the fourth collar and the outer diameter of the third collar is larger than the inner diameter of the second collar.
Claim 13
Dependent Claim
62 words
The joint for collapsible ladders as set forth in claim 11, wherein an opening is provided in each flange portion for each angular position in which the ladder is to be locked in position by the passage of a locking rod portion and the corresponding openings in each flange portion only overlap when these angular positions are assumed by the flange portions.
Claim 14
Dependent Claim
66 words
The joint for collapsible ladders as set forth in claim 12, wherein one of said overlapping openings in one of the flange portions when the two flange portions assume an acute angle relative to each other, is formed as a concentric circular slot with respect to the hinge pin which permits a swinging of both shaft portions when the locking member is in the locking position.
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) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |