US4257491A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scaffold apparatus
Assignee: Prescon Corp
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Filing: 1979-01-29
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Granted: 1981-03-24
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Expires: 1999-01-29
Abstract
Abstract An enclosed scaffold is suspended from a plurality of wire lines attached near the apex of a hemispheric dome surmounting the cylindrical sides of a containment structure, e.g. a tank. The scaffold is attached to the wire lines by hydraulically actuated cable gripping and climbing devices which may be manually or automatically controlled to raise and lower the scaffold. A wheel mounted car rides on the face of a buttress on the exterior of the containment structure wall. A boom mounted on the car is pivotally attached to the top of the scaffold. By means of a hydraulic thruster mounted on the car, the points of attachment of the scaffold to the boom can be moved away from or toward the buttress and wall as needed to provide room for the scaffold to hang level when it moves over the curved part of the structure. To balance torques on the scaffold tending to keep it from hanging level, guide channels carried by the lower part of the car engage rollers carried by the lower part of the scaffold, the roller position with respect to the guide channels being adjustable by screw jacks. The radial component of the force exerted on the scaffold by the wire lines keeps the car wheels in positive engagement with the buttress at all points above the springline. Below the springline, guide rails temporarily bolted to the buttress hold the car wheels against the buttress, thereby to maintain the scaffold level. The scaffold may be adapted to different buttress configurations and may be adapted to receive and suspend pup scaffolds for operating over the vertical part of the structure wall.
Inventors
- 👤 Homer H. Presnall, Jr.
- 👤 Earl G. Cutler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:21
CPC Classifications
E; E04; E04G; E04G3/00; E04G3/24; E04G3/22; E04G3/243; E04G3/28; E04G3/30
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
130 words
Scaffold apparatus comprising a car adapted to move over a surface curved in elevation; positionable means adapted to be positioned relative to such surface; said positionable means including connector means for use in making a pivotal connection to a scaffold, support means movably mounting the connector means on the car, thrust means for moving the connector means relative to the car; said car including a chassis carrying rotatable means to support the car on such surface and a boom extending transversely to the chassis providing said support means for the connector means; and said boom including a pair of racks each connected at one end to the chassis and a cross member reciprocably movable on said racks, said connector means including a pair of hangers positioned on said cross member.
Claim 2
Dependent Claim
130 words
Scaffold apparatus comprising a car adapted to move over a surface curved in elevation; positionable means adapted to be positioned relative to such surface; said positionable means including connector means for use in making a pivotal connection to a scaffold, support means movably mounting the connector means on the car, thrust means for moving the connector means relative to the car; said car including a chassis carrying rotatable means to support the car on such surface and a boom extending transversely to the chassis providing said support means for the connector means; and said boom including a pair of racks each connected at one end to the chassis and a cross member reciprocably movable on said racks, said connector means including a pair of hangers positioned on said cross member.
Claim 3
Dependent Claim
22 words
Apparatus according to claim 1, said thrust means comprising a hydraulic jack, said support means including guide means for said connector means.
Claim 4
Dependent Claim
25 words
Apparatus according to claim 1, said thrust means comprising gear means adapted for engaging said racks and hydraulic jack means for moving said gear means.
Claim 5
Dependent Claim
52 words
Apparatus according to claim 3, said gear means comprising a pair of gears rotatably disposed on said cross member, said gears engaging said racks to move the cross member in and out relative to the chassis as the gears are rotated in one direction and the other by said hydraulic jack means.
Claim 6
Dependent Claim
19 words
Apparatus according to claim 4, said boom including means for limiting the travel of said gears on said racks.
Claim 7
Dependent Claim
87 words
Scaffold apparatus comprising a car adapted to move over a surface curved in elevation, positionable means adapted to be positioned relative to such surface, said positionable means including connector means for use in making a pivotal connection to a scaffold, support means movably mounting the connector means on the car, thrust means for moving the connector means relative to the car, and said car including first guide means cooperable with second guide means on a scaffold to level such scaffold when pivotally connected to said connection means.
Claim 8
Dependent Claim
87 words
Scaffold apparatus comprising a car adapted to move over a surface curved in elevation, positionable means adapted to be positioned relative to such surface, said positionable means including connector means for use in making a pivotal connection to a scaffold, support means movably mounting the connector means on the car, thrust means for moving the connector means relative to the car, and said car including first guide means cooperable with second guide means on a scaffold to level such scaffold when pivotally connected to said connection means.
Claim 9
Dependent Claim
107 words
Scaffold apparatus comprising a car adapted to move over a surface curved in elevation, positionable means adapted to be positioned relative to such surface, said positionable means including connector means for use in making a pivotal connection to a scaffold, support means movably mounting the connector means on the car, thrust means for moving the connector means relative to the car, said positionable means including a scaffold pivotally connected to said connector means, and the pivot axis of said connector means being located at a distance from the point of suspension of said scaffold, said car and said scaffold including cooperable guide means for leveling the scaffold.
Claim 10
Dependent Claim
107 words
Scaffold apparatus comprising a car adapted to move over a surface curved in elevation, positionable means adapted to be positioned relative to such surface, said positionable means including connector means for use in making a pivotal connection to a scaffold, support means movably mounting the connector means on the car, thrust means for moving the connector means relative to the car, said positionable means including a scaffold pivotally connected to said connector means, and the pivot axis of said connector means being located at a distance from the point of suspension of said scaffold, said car and said scaffold including cooperable guide means for leveling the scaffold.
Claim 11
Dependent Claim
41 words
Apparatus according to claim 7, said scaffold including an upper portion and a lower portion, said connector pivotally connecting the car to the upper portion of the scaffold and said cooperable guide means acting on the lower portion of the scaffold.
Claim 12
Dependent Claim
87 words
Scaffold apparatus comprising a car adapted to move over a surface curved in elevation, positionable means adapted to be positioned relative to such surface, said positionable means including connector means for use in making a pivotal connection to a scaffold, support means movably mounting the connector means on the car, thrust means for moving the connector means relative to the car, said positionable means including a scaffold pivotally connected to said connector means, and said car and said scaffold including cooperable guide means for leveling the scaffold.
Claim 13
Dependent Claim
87 words
Scaffold apparatus comprising a car adapted to move over a surface curved in elevation, positionable means adapted to be positioned relative to such surface, said positionable means including connector means for use in making a pivotal connection to a scaffold, support means movably mounting the connector means on the car, thrust means for moving the connector means relative to the car, said positionable means including a scaffold pivotally connected to said connector means, and said car and said scaffold including cooperable guide means for leveling the scaffold.
Claim 14
Dependent Claim
41 words
Apparatus according to claim 9, said car including rotatable means to support said car on said surface, said scaffold including line climbing means adapted to engage flexible line means for suspending the scaffold and pressing said rotatable means against the surface.
Claim 15
Dependent Claim
39 words
Apparatus according to claim 9, said cooperable guide means including a track connected to said car, a roller movable in said track, linkage connecting said roller to said scaffold, and jack means for adjusting the position of said linkage.
Claim 16
Dependent Claim
101 words
Scaffold apparatus comprising a car adapted to move over a surface curved in elevation, positionable means adapted to be positioned relative to such surface, said positionable means including connector means for use in making a pivotal connection to a scaffold, support means movably mounting the connector means on the car, thrust means for moving the connector means relative to the car, said positionable means including a scaffold pivotally connected to said connector means, and said scaffold having an inset in its perimeter adapting the scaffold to fit around a buttress on such curved surface, said car being received in said inset.
Claim 17
Dependent Claim
101 words
Scaffold apparatus comprising a car adapted to move over a surface curved in elevation, positionable means adapted to be positioned relative to such surface, said positionable means including connector means for use in making a pivotal connection to a scaffold, support means movably mounting the connector means on the car, thrust means for moving the connector means relative to the car, said positionable means including a scaffold pivotally connected to said connector means, and said scaffold having an inset in its perimeter adapting the scaffold to fit around a buttress on such curved surface, said car being received in said inset.
Claim 18
Dependent Claim
36 words
Apparatus according to claim 12, said car including a chassis nested in said inset and a boom extending transversely from said chassis over the top of said scaffold, said support means being carried by the boom.
Claim 19
Dependent Claim
33 words
Apparatus according to claim 12, said scaffold including rotatable means for engaging such surface at either side of such buttress and said car including rotatable means for engaging the sides of such buttress.
Claim 20
Dependent Claim
59 words
Apparatus according to claim 12, said scaffold including rotatable means for engaging such surface at either side of such buttress, said car including at each side of the car rollers mounted thereon for engaging vertically extending mutually perpendicular surfaces removably secured to the sides of such buttress where the buttress continues along a vertical continuation of such curved surface.
Claim 21
Dependent Claim
53 words
Apparatus according to claim 12, said scaffold including rotatable means for engaging such surface at either side of such buttress, said scaffold further including docking stations at each side of buttress with pup scaffold means connected to the first said scaffold and adapted to be moved into and out of said docking stations.
Claim 22
Dependent Claim
43 words
Apparatus according to claim 16, said pup scaffold means being provided with eyes by which it can be pinned to the first said scaffold or suspended therefrom with wire lines and with support tubes by which it can be supported from adjacent structure.
Claim 23
Dependent Claim
98 words
Apparatus according to claim 12, in combination with a structure providing such surface and a plurality of lines connected to said structure at a top portion of said surface extending down through line climbing means included in said scaffold, said structure further providing a second surface that is straight in elevation which extends below the first said surface, and said structure including such buttress extending vertically along said second surface and thence upwardly along said curved surface, said buttress having perpendicular extensions along each side engageable with outriggers carrying rotatable means on said car on opposite sides thereof.
References Cited (Backward Citations)
US3095060A
Cited
US4132287A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-23 | 1984-09-22 | 1985-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-23 | 1988-09-22 | 1989-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-23 | 1992-09-22 | 1993-03-24 | $7700.00 | Window Closed / Lapsed |