Flexible or portable closure – partition – or panel – With hood – canopy – shield storage chamber – or outrigged... – For roll type
Reexamination Certificate
1999-09-27
2001-06-12
Purol, David M. (Department: 3634)
Flexible or portable closure, partition, or panel
With hood, canopy, shield storage chamber, or outrigged...
For roll type
C160S290100, C160S311000
Reexamination Certificate
active
06244324
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an extendable and retractable barrier.
BACKGROUND OF THE INVENTION
Assemblies making use of an axially movable member threadedly mounted on a screw and connected to a spiral spring motor, in lowering and raising a window shade are illustrated by U.S. Pat. No. 4,427,050 to Toppen and U.S. Pat. No. 4,523,620 to Mortellite. As the axially movable member rotates when the shade is lowered, the spring motor is increased in tension. Also known as exemplified by U.S. Pat. No. 5,484,051 to Nagai et al, is the use of an axially movable member threadedly mounted on a rotatable ball screw shaft coupled to a rotatable shaft of an electric motor, with rodless cylinders including pistons movable by fluid pressure, for vertically moving a workpiece. In addition, as illustrated by U.S. Pat. No. 5,370,367 to Zaguroli, Jr., an axially movable ball nut threadedly mounted on a ball screw fixed within a drum reel for a cable, is known to be rotatable by regulated air pressure applied to the drum reel. In an embodiment of the zaguroli device, piston and cylinder shock absorbers pressurized by a source of compressed air, oppose cable wind up.
However, none of this prior art provides a barrier attached, in use, at both ends to support surfaces, and extendable and retractable beneficially in response to a changing environment of use. In such case, extension or retraction of the barrier as needed, could prevent damage to, or tearing or even destruction of, the barrier. Moreover, none of this prior art provides a barrier in combination with an extension and retraction mechanism that exerts substantially constant force regardless of the barrier extent. Furthermore, none of this prior art provides a barrier useful as a visual barrier and extending between coupled passenger rail cars for reducing the possibility that a visually impaired person intending to step into a rail car, might accidentally step off a train platform onto the tracks.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided an extendable/retractable barrier including an end attachable to a support surface, and an opposite end fixed to a rotatable cylinder in operative connection with a barrier extension and retraction mechanism. Beneficially, the extension and retraction mechanism exerts a substantially constant opposing force against barrier extension and likewise a substantially constant retractive force, regardless of the barrier extent. Advantageously, this mechanism includes a shaft and an axially movable nut threadedly mounted thereon and connected to gas springs, and axial movement of the nut on the shaft upon extending the barrier, applies force to the gas springs. In a preferred embodiment, a ball screw nut is threadedly mounted on a ball screw, and is connected to gas springs having a substantially flat force curve.
The term “substantially” for purposes of this description, is best understood by consideration of force vs. displacement from which it can be seen that for certain gas springs only a small increase in force results with increased displacement, whereas by comparison a very significant increase in force occurs with increased displacement for a spiral spring as in the Toppen or Mortellite or Zaguroli devices. Thus, the term “substantially” is intended to embrace a small amount of change in force, typically less than about 20 to 30% change, usually about 5 to 10% change, but in any event is intended to distinguish from a change of 50% or more.
Advantageously, the rotatable cylinder is disposed in a housing having an opening through which the barrier is extended and retracted. Beneficially, the opening is formed in part by a wall of the housing having an angled wall portion, and a second rotatable cylinder is disposed within the housing at the entrance to the opening.
In a useful embodiment, the rotatable cylinder for the barrier is disposed in a first housing, and the shaft, axially movable nut and gas springs are disposed in a second housing, and the first housing and the second housing are disposed in a side-by-side relationship, and are fastened to, but easily separable from, one another for interchangeability of housings.
Beneficially, the attachable barrier end includes at least one eyelet to be captured, retained and released by a cooperating mechanism attached to a support structure. A preferred latch and release mechanism includes an elongated mounting plate to be attached to a support structure, and a plurality of spaced apart projections extending from the mounting plate and disposed generally perpendicular to the mounting plate. The projections include aligned apertures, and the mechanism includes a spring-biased retention pin movable between an eyelet retention position, and an eyelet release position in which it is retracted clear of the eyelet.
Additional advantages and beneficial features of the present invention are set forth in the drawing and detailed description, and in part will become apparent to those skilled in the art upon examination of the drawing and detailed description or may be learned by practice of the invention. In the drawing and detailed description, there are shown and essentially described only preferred embodiments of this invention, simply by way of illustration of the best mode contemplated of carrying out this invention. As will be realized, this invention is capable of other and different embodiments, and its several details are capable of modification in various respects, all without departing from the invention. Accordingly, the drawing and the detailed description are to be regarded as illustrative in nature, and not as restrictive.
REFERENCES:
patent: 1097949 (1914-05-01), Sparks
patent: 1119499 (1914-12-01), Donaldson et al.
patent: 1217210 (1917-02-01), Packer
patent: 2503773 (1950-04-01), Schuster et al.
patent: 3465805 (1969-09-01), Lyman
patent: 4427050 (1984-01-01), Toppen
patent: 4523620 (1985-06-01), Mortellite
patent: 5148848 (1992-09-01), Murray et al.
patent: 5292169 (1994-03-01), O'Brian
patent: 5370367 (1994-12-01), Zaguroli, Jr.
patent: 5484051 (1996-01-01), Nagai et al.
patent: 5860440 (1999-01-01), Murray et al.
Ketcham David P.
Quates Robert B.
Kroboth Timothy R.
Purol David M.
Total Retraction Inc.
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