Chain Drive System For Use In A Theatre

Abstract

A system for suspending a vertical curtain (especially a theatrical curtain) and for driving the curtain to move horizontally (for example, between a position covering a stage and a position not covering a stage). The curtain is suspended directly from a drive chain, along at least a portion of the drive chain, by chain attachment structures. Also, a rotating switch that can be actuated by a switch attachment structure supported by the drive chain. Also, the use of a dedicated encoder sprocket which is separate from the guide sprockets.

1 . A system for suspending a curtain and for driving a curtain in a generally horizontal direction, the system comprising:
 a curtain;   a drive chain loop;   a plurality of chain attachment structures; and   a plurality of sprocket assemblies;   wherein:   the drive chain loop is made at least substantially entirely of drive chain;   the plurality of sprocket assemblies each comprise: a sprocket, and a support sub-assembly structured and/or located to support the sprocket in an at least generally horizontal position so that all of the sprockets of the plurality of sprocket assemblies have an at least generally coplanar orientation;   the drive chain is in sprocket-and-chain engagement with each sprocket of the plurality of sprockets;   the plurality of chain attachment structures are mechanically connected to the drive chain; and   the curtain is mechanically connected to each of the chain attachment structures of the plurality of chain attachment structures so that the curtain will move when the chain is driven to move.   
     
     
         2 . The system of  claim 1  wherein the drive chain loop is made at least substantially entirely of standard roller chain. 
     
     
         3 . The system of  claim 1  wherein each chain attachment structure, of the plurality of chain attachment structures comprise:
 a U-shaped bracket; and 
 a wire clip member. 
 
     
     
         4 . The system of  claim 3  wherein the U-shaped bracket member includes:
 a base portion that is structured to act as a roller chain plate; and 
 a pair of arms, each arm defining at least one hole, with the pair of arms extending from the base portion in an at least generally perpendicular direction. 
 
     
     
         5 . The system of  claim 4  wherein:
 the wire clip member includes:
 a generally U-shaped portion including a base portion and a pair of arms extending from the base portion, and 
 a pair of securement arms respectively extending at an angle from each arm of the U-shaped portion; 
 
 the wire clip member is shaped so that the securement arms respectively engage with the holes defined in the generally U-shaped bracket member; and 
 the wire clip member is further structured so that its generally U-shaped portion is slightly compressed from its at-rest position when it is engaged with the U-shaped bracket member. 
 
     
     
         6 . The system of  claim 5  wherein the securement arms respectively extend at a generally acute angle from the pair of arms of the wire clip. 
     
     
         7 . The system of  claim 6  wherein the wire clip is made from cylindrical spring wire. 
     
     
         8 . A system for suspending a curtain and for driving a curtain in a generally horizontal direction, the system comprising:
 a curtain;   a loop;   a plurality of curtain support structures;   a switch attachment structure;   a switch assembly; and   a plurality of loop supporting assemblies;   wherein:   the curtain, the loop and the plurality of curtain support structures are located, structured and/or connected so that the curtain is pended from the loop by the plurality of curtain support structures;   the plurality of loop supporting assemblies each comprise: a loop guide, and a support sub-assembly structured and/or located to support the loop guide in an at least generally horizontal position so that all of the loop guides of the plurality of loop guides have an at least generally coplanar orientation;   the loop is engaged with and defined in its shape by each loop guide of the plurality of loop guides;   the switch attachment structure is mechanically connected to the loop;   the switch assembly comprises a switch movable between a first position and a second position; and   the switch assembly, the loop and the switch attachment structure are structured and/or located so that the switch attachment structure will: (i) move the switch by physical interference from the first position to the second position when the loop and switch attachment structure move past the switch assembly in a first direction; and (ii) move the switch by physical interference from the second position to the second position when the loop and switch attachment structure move past the switch assembly in a second direction which is opposite the first direction.   
     
     
         9 . The system of  claim 8  wherein the switch rotates between the first position and the second position about an axis of rotation that is at least generally vertical. 
     
     
         10 . The system of  claim 9  wherein:
 the switch comprises a first protrusion and a second protrusion; and 
 the switch attachment structure hits the first protrusion to rotate the switch as it moves past the switch assembly in the first direction; and 
 the switch attachment structure hits the second protrusion to rotate the switch as it moves past the switch assembly in the second direction. 
 
     
     
         11 . The system of  claim 8  wherein:
 the loop is made at least substantially entirely of drive chain; 
 the loop guides are sprockets; and 
 the loop is in chain-and-sprocket engagement with the loop guides. 
 
     
     
         12 . The system of  claim 11  wherein the chain is standard roller chain. 
     
     
         13 . A system for suspending a curtain and for driving a curtain in a generally horizontal direction, the system comprising:
 a curtain;   a drive chain loop;   a plurality of chain attachment structures;   a plurality of sprocket assemblies;   an encoder sprocket; and   an encoder   wherein:   the drive chain loop is made at least substantially entirely of drive chain;   the plurality of sprocket assemblies each comprise: a guide sprocket, and a support sub-assembly structured and/or located to support the sprocket in an at least generally horizontal position so that all of the sprockets of the plurality of sprocket assemblies have an at least generally coplanar orientation;   the drive chain is in sprocket-and-chain engagement with each sprocket of the plurality of sprockets;   the plurality of chain attachment structures are mechanically connected to the drive chain;   the curtain is mechanically connected to each of the chain attachment structures of the plurality of chain attachment structures so that the curtain will move when the chain is driven to move;   the encoder sprocket is not in chain-and-sprocket engagement with the drive chain;   the encoder sprocket is structured, located and/or connected to rotate corresponding to motion of the drive chain; and   the encoder is operatively coupled to the encoder sprocket to quantitatively detect rotation of the encoder sprocket.   
     
     
         14 . The system of  claim 13  wherein the encoder sprocket is engaged with one of the guide sprockets so that rotation of the guide sprocket will drive the encoder sprocket to rotate.