초록 ▼

A positive drive for window shades and the like is characterized, first of all, by an opposed pair of channel-shaped tracks confining the right and left side margins of the shade and each also housing one run of an endless chain reaved under a pulley at the bottom and over a sprocket at the top. The

A positive drive for window shades and the like is characterized, first of all, by an opposed pair of channel-shaped tracks confining the right and left side margins of the shade and each also housing one run of an endless chain reaved under a pulley at the bottom and over a sprocket at the top. The bottom of the shade carries a rigid hem bar having eyelets in its ends sized to pass the chain but not a pair of stops carried by the latter that engage the hem bar and unwind the shade off the roller it is wound upon at the top when an exposed run of one of the chains is pulled. Right and lefthand one-way clutches are interposed between the sprockets and roller operative when the shade is lowered to disengage and permit relative rotational movement between the shade drive mechanism and the roller until the stops engage the eyelets in the hem bar. These same clutches engage when the shade is raised to link the drive mechanism and shade roller together for conjoint rotation.

대표청구항 ▼

The drive mechanism for window shades and the like which comprises: a pair of channel-shaped tracks arranged in side-by-side spaced parallel and opposed relation to one another; a pair of drive wheel means positioned in spaced relation atop the tracks for rotation about a common axis extending trans

The drive mechanism for window shades and the like which comprises: a pair of channel-shaped tracks arranged in side-by-side spaced parallel and opposed relation to one another; a pair of drive wheel means positioned in spaced relation atop the tracks for rotation about a common axis extending transversely therebetween; a pair of idler wheel means positioned in spaced relation at the bottom of the tracks for rotation about a common axis extending transversely therebetween in aligned relation with one of the drive wheel means; endless loop actuating means reaved around the aligned drive and idler wheel means; a pair of transversely aligned stop-forming means attached to the actuating means; a shaft extending between the drive wheel means linking same together for conjoint rotation; a roller mounted upon the shaft for relative rotational movement independent thereof; a shade wound upon the roller, said shade having a bottom margin and side margins confined within the channel-shaped tracks for movement therein between a raised and lowered position; rigid means extending along the bottom margin of the shade, said means having eyelets at the opposite ends thereof sized to pass the actuating means while forming abutments to the passage of the stop-forming means; and left and righthanded one way clutch means operatively interconnecting the drive wheel means and the roller, said clutches being operative to engage and form a driving connection between the drive wheel means and said roller effective to raise the shade upon actuation of the actuating means in one direction, and said clutches being operative to disengage the drive wheel means from said roller and permit relative rotational movement to take place therebetween upon actuation of the actuating means in the opposite direction, said stop-forming means and eyelets being operative to interengage with the clutches thus disengaged to lower the shade.