Abstract: A venetian blind (10) includes a headrail (11), a series of horizontal slats (12), a bottom rail (18) and lift cords (14) to raise and lower the slats and bottom rail, the slats each including spaced marquise shape apertures (22), called rout holes, through which a lift cord (14) passes. The spaced elliptical apertures are of less width and less length than the conventional rout holes heretofore employed. A substantial reduction of visible light through the apertures is achieved in the slats-tilted-closed position by a reduction of about 73% in the light-passing open space between the lift cord and the rout hole edges. The smaller size of the rout holes increases the structural rigidity and integrity of the remaining slat portions next to the rout holes and reduces the visual defect of the larger holes.

Abstract: Venetian blind slats are stacked and clamped onto a support, and confined laterally, while leaving ends beyond the desired length to which they are to be cut, un-confined. Then in one stroke in a direction perpendicular to the support, the ends of the stack are sheared-off by a punching tool having a cutting edge which contacts longitudinal margins prior to the center of the slats.

Abstract: A venetian blind tilt drum eliminates the separate staples, crimped sleeves and bullet-like members normally used to connect the vertical legs of a cord tilt ladder to the drum. The tilt drum is of one-piece construction and includes a top surface from which preferably three cord impalement integral barbs extend. A first barb of generally pyramidal shape is positioned on an upper top surface of the drum on the drum vertical centerline, parallel to the longitudinal axis of the drum and with a pointed vertex of the barb extending above that axis. A pair of similar second and third barbs also integral with the drum are offset from the drum vertical centerline, with each pointed vertex also parallel to the drum longitudinal axis but extending in an opposite direction than the first barb. Depending on the particular tilt ladder construction the upper distal ends of the tilt ladder both may be impaled on the first barb or one distal end impaled on the second barb and the other distal end impaled on the third barb.