Flexible or portable closure – partition – or panel – Plural strip – slat – or panel type – Venetian blind type
Reexamination Certificate
2000-02-11
2001-09-18
Johnson, Blair M. (Department: 3634)
Flexible or portable closure, partition, or panel
Plural strip, slat, or panel type
Venetian blind type
C160S084040, C160S17300V, C242S373000, C242S378400
Reexamination Certificate
active
06289965
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to counterbalances, and more particularly relates to take-up drums for use with spring motors.
BACKGROUND OF THE INVENTION
Spring motors are well-known and generally comprise a flat ribbon of spring metal which is pre-stressed on one side and coiled so as to have a natural or relaxed state in which the spring forms a tightly wound coil. The coil is normally disposed on or in a storage or take-up drum. The free end of the coil is attached to the hub of an output or drive drum onto which the spring is back wound by rotating the output drum in the direction to back wind the spring thereon. When the holding force by which the spring is back wound on the output drum is released, the curling property of the spring rewinds the latter onto or into the storage or take-up drum towards its natural or relaxed state. This resulting motion can be utilized in a number of applications requiring reciprocating motion such as with seat belts, cordless blinds and the like.
The spring member in such spring motors can be of constant or variable force depending upon the intended use for the motor. The variable force characteristic can be obtained in a number of ways including tapering the width and or thickness of the spring as disclosed in U.S. Pat. Nos. 5,482,100 and 5,531,257. Such patents are directed to the use of spring motors in conjunction with a cordless window blind.
In the aforementioned patents, a cord drum is provided lateral to, and concentric with, the drive drum such that rotation of the cord spool causes rotation of the drive drum. Rotation of the drive drum in turn uncoils the spring from the take-up drum and back winds the spring onto the drive drum. A cord is connected between the cord drum and the bottom rail of the blind. When the blind is extended downwardly, this rotation pulls the cord from the cord spool which in turn rotates the cord spool, the drive drum, and the take-up drum. The spring motor facilitates smooth motion of the bottom rail.
In still further devices, the cord spool or spools are provided in a linear arrangement with the axis of the take-up drum, drive drum and cord spools being parallel. Typically, two cord spools are provided, one adjacent the drive drum, and one adjacent the take-up drum. In order to transfer torque from the cord spools to the drive drum, the cord spools are provided with radially extending gear teeth which mesh with mating teeth on the drive drum. In one case, the cord spool teeth mesh with teeth of an idler gear mounted proximate the take-up drum, and the idler gear then meshes with the drive drum. The take-up drum and idler gear are mounted on the same axis and concentric with one another, with the take-up drum being provided with a recess on one side about which the idler gear rotates.
While such systems are workable, the idler gear and take-up drum can tend to bind and not freely rotate, which necessarily detrimentally affects performance of the coil spring. More specifically, if the take-up drum is not allowed to freely rotate, the coil can tend to “grow” in that it is not tightly wound about the take-up drum. As a result the coil spring loses force and may become disengaged from the take-up drum. Such binding can occur because the rotational force on the gear necessarily side loads the axle or hub or around which it rotates causing excess friction and/or disproportionate rotation of the idler spool.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, a spring motor is provided which comprises a frame, a drive drum rotatably mounted to the frame, an idler gear rotatably mounted to the frame, a take-up drum rotatably mounted and concentric with the idler gear, and a coil spring interconnected between the take-up drum and the drive drum. The idler gear is operably connected to the drive gear such that rotation of the idler gear causes rotation of the drive drum. The idler gear is rotatable independent of the take-up drum and the coil spring is biased into a wound orientation on the take-up drum.
In accordance with other aspects of the invention, the idler gear includes a cylindrical hub with first and second ends, and a toothed flange radially extending from the first end. The first and second ends are rotationally supported by the frame with the take-up drum being rotationally supported on the cylindrical hub. A cylindrical hub includes first and second laterally spaced bearing surfaces around which the take-up drum rotates.
In accordance with another aspect of the present invention, a blind is provided comprising a head rail, a bottom rail, a plurality of slats between the head rail and the bottom rail, at least one cord interconnecting the head rail, bottom rail and the plurality of slats, and a spring motor mounted in one of the head rail and bottom rail. The spring motor comprises a frame, a drive drum rotatably mounted to the frame, an idler gear rotatably mounted to the frame and operably connected to the drive gear, at least one cord spool rotatably mounted to the frame and operably connected to the idler gear, a take-up drum rotatably mounted on, and concentric with, the idler gear, and a coil spring interconnected between the take-up drum and the drive drum. Rotation of the idler gear causes rotation of the drive drum, rotation of the cord spool causes rotation of the idler gear, and the idler gear is rotatable independent of the take-up drum. The at least one cord is connected to the at least one cord spool. The coil spring is biased into a wound orientation on the take-up drum.
In accordance with another aspect of the present invention, an idler gear and take-up drum assembly for a spring motor is provided which comprises a central hub having a through aperture and first and second ends, a flange radially extending from the first end of the central hub, and a spool rotationally mounted onto the central hub. The central hub is adapted to support the first and second ends for rotation within the through aperture, and the spool includes a hub with first and second radially extending flanges.
In accordance with yet another aspect of the invention, a spring motor is provided which comprises a frame, a drive drum rotatably mounted to the frame, a take-up drum rotatably mounted to the frame, a coil spring interconnected between the drive drum and the take-up drum, a cord spool rotatably mounted to the frame, and means for transferring torque from the cord spool to the drive drum while permitting the take-up drum to rotate freely. The drive drum, take-up drum, and cord spool are linearly aligned with parallel axes of rotation, and with the take-up drum being interposed between the drive drum and the take-up drum.
These and other aspects and features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 13251 (1855-07-01), Bixler
patent: 322732 (1885-07-01), Lang
patent: 842401 (1907-01-01), Goodell
patent: 927090 (1909-07-01), Anderson
patent: 948239 (1910-02-01), McManus
patent: 1636601 (1927-07-01), Givens
patent: 1721501 (1929-07-01), McKee
patent: 1731124 (1929-10-01), Carper
patent: 1789655 (1931-01-01), Iwata
patent: 1951659 (1934-02-01), Kesner
patent: 2037393 (1936-04-01), Roberts
patent: 2049518 (1936-08-01), Schier
patent: 2110983 (1938-03-01), Carver
patent: 2175549 (1939-10-01), Nardulli et al.
patent: 2250106 (1941-07-01), Lorentzen
patent: 2260101 (1941-10-01), De Falco
patent: 2266160 (1941-12-01), Burns
patent: 2276716 (1942-03-01), Cardona
patent: 2324536 (1943-07-01), Pratt
patent: 2325992 (1943-08-01), Wirthman
patent: 2350094 (1944-05-01), Butts
patent: 2390826 (1945-12-01), Cohn
patent: 2410549 (1946-11-01), Olson
patent: 2420301 (1947-05-01), Cusumano
patent: 2509033 (1950-05-01), Carver
patent: 2520629 (1950-08-01), Esposito
patent: 2535751 (1950-12-01), Nardulli
patent: 2598887 (1952-06-01), Burns
patent: 2687769 (1954-08-01), Gershuny
patent: 2824608 (1958-02-01), Etten
patent: 2869801 (1959-01-01), Foster
patent: 28
Johnson Blair M.
Marshall Gerstein & Borun
Newell Operating Company
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