An object of the present invention is to provide a tensioner that has a reduced number of components and lighter weight and is easy to assemble. The tensioner according to the present invention is configured such that a base member is detachably and mechanically joined to a rear end opening of a cylindrical plunger with a closed front end against the resilience of biasing means that is accommodated inside the plunger such as to be freely extend and contract. The joint between the plunger and the base member is a mechanical connection that is one of a thread engagement, a press-fit, and a pin connection.

Tensioning apparatus (10, 30, 130) for applying a required tension to a line means (12, 32, 132). A body (14, 34, 134) is provided which provides first (26, 50, 150), second (20, 60, 160) and third (28, 52, 152) parts with contact surfaces engagable with the line means so as to urge the line means from a straight alignment to provide a required tension therein. The second part (60, 62) may be adjustably movable relative to the first (50, 150) and third (52, 152) parts.

A manual drive assembly for a manually-operated window treatment based on a drive chain formed as a loop, may incorporate one or more intermediate tensioners disposed between two ends of the loop. The loop may be formed between a manual clutch mechanism coupled to the window treatment and an end tensioner. The one or more intermediate tensioners may serve to limit slack in the loop such that sides of the loop cannot be pulled to create a large loop, for example, having a gap of four inches or greater, between the hanging sides of the cord.

An object of the present invention is to provide a tensioner lever that can reliably prevent displacement or detachment of a torsion coil spring, prevent the torsion coil spring from interfering with an attachment surface, and allow smooth attachment of the tensioner lever to the attachment surface. The tensioner lever includes a lever body having a shoe surface, and a torsion coil spring pressing the shoe surface toward a chain. The lever body includes a base part and a cylindrical boss. The torsion coil spring includes a helical part loosely fitted on an outer circumferential surface of the boss, a pressing arm making contact with the lever body, and a support arm supported on the attachment surface. The outer circumferential surface of the boss includes a restricting protrusion formed at a position closer to the attachment surface than the helical part.

The problem to be solved is to provide a tensioner lever that inhibits friction-induced wear or seizure on a surface of a pivoting support boss contacting a shoulder bolt so that high durability is achieved, and that is easily producible and enables cost reduction. As a solution to the problem noted above, the tensioner lever includes a shoe having a traveling surface, a lever body, and a pivotal support boss provided at a proximal end of the lever body to allow a distal end thereof to swing. The shoe and the lever body are integrally formed and assembled together by double injection molding. The lever body includes a slide bearing member, and a connecting part that connects the slide bearing member and the shoe. The slide bearing member, the connecting part, and the shoe are made of the same synthetic resin, and configured as a continuous one-piece component.

A tensioning rail (2) for tensioning an endlessly circulating tensioner (4) is provided, wherein the tensioning rail (2) for tensioning the ternsioner (4) is curved in a longitudinal direction (L), the tensioning rail (2) has a base wall (6) and two jaws (8) protruding from the base wall (6), and the tensioning rail (2) has at least one U-shaped profiled segment (10) and a T-shaped profiled segment (12), which are each formed by the base wall (6) and the jaws (8), wherein the tensioning rail (2) includes a guiding element (14) for a rotary bearing (16) in the U-shaped profiled segment (10) and a guiding element (18) for a contact bearing (20) in the T-shaped profiled segment (12).

A manual drive assembly for a manually-operated window treatment based on a drive chain formed as a loop, may incorporate one or more intermediate tensioners disposed between two ends of the loop. The loop may be formed between a manual clutch mechanism coupled to the window treatment and an end tensioner. The one or more intermediate tensioners may serveto limit slack in the loop such that sides of the loop cannot be pulled to create a large loop, for example, having a gap of four inches or greater, between the hanging sides of the cord.

A chain tensioning device which combats natural build-up of chain slack. In controlling the chain slack, the torque at which a chain jumps occurs is delayed resulting in a higher jump torque performance.

An object of the present invention is to provide a chain guide mechanism that can readily integrate all the components in a simple structure and enhance work efficiency during assembly or maintenance. The chain guide mechanism of the present invention is configured to be able to integrally support, on a frame, components including a plurality of sprockets, a chain, a fixed chain guide, and a pivoting chain guide. The frame includes a pivoting chain guide holding part that holds a mounting boss of the pivoting chain guide in a state of a loose fit. The pivoting chain guide holding part is configured to allow the mounting boss to be fitted therethrough from one side.

An object of the present invention is to provide a tensioner lever capable of consistently exerting appropriate reaction force to various tension fluctuations in conjunction with varying chain behavior, and reducing vibration and noise when the chain runs. The tensioner lever of the present invention includes a torsion coil spring having a pressing arm in which a distal end portion abuts on a lever body to form a first load point, and a support arm in which a distal end portion abuts on a support part provided to an attachment surface to form a first support point. The tensioner lever further includes a spring load adaption structure configured to form one or both of a second loading point and a second support point when a certain level or more of load is received from the chain.