Floating optical sensor mount

Abstract

A piston-cylinder actuator ( 20 ) includes a unique mount ( 36 ) for an absolute-position sensor ( 30 ). The mount ( 36 ) is made from a bearing material provides a flexible connection between the sensor mount ( 36 ) and the cylinder housing ( 40 ). This flexible connection allows the piston rod ( 32 ) to deflect naturally, under its own weight or under other laterally-directed forces, while maintaining the distance and perpendicularity between the sensor ( 30 ) and the rod surface ( 34 ), within acceptable limits. The sensor mount ( 36 ) is made from a bearing material that will allow it to float directly on the rod surface ( 34 ) without scuffing or otherwise damaging the rod surface ( 34 ), particularly the markings or other indicia on that surface ( 34 ). Due to the flexible connection between the sensor mount ( 36 ) and the cylinder housing ( 40 ), the proper distance between the sensor ( 30 ) and the rod surface ( 34 ) can be maintained at all times.

1 - 15 . (canceled) 
     
     
         16 . A piston-cylinder actuator, comprising:
 a cylinder assembly including a cylinder housing that defines a cylindrical volume, the cylinder housing having a longitudinal axis;   a piston assembly generally movable relative to the cylinder assembly along the longitudinal axis, the piston assembly including a piston rod having indicia extending longitudinally on a surface of the rod;   a sensor capable of reading the indicia on the piston rod; and   means for supporting the sensor relative to the piston rod;   where the support means includes a bearing surface for interfacing with the piston rod and an aperture transverse the bearing surface to provide the sensor with access to indicia, and the support means is flexibly connected to the cylinder housing to pivot relative to the cylinder housing while maintaining the sensor at a substantially constant position along the longitudinal axis relative to the cylinder housing.   
     
     
         17 . An actuator as set forth in  claim 16 , where the support means includes a sensor mount made of a bearing material. 
     
     
         18 . An actuator as set forth in  claim 16 , where the cylinder assembly includes a seal gland mounted in the cylinder housing, the seal gland having a central aperture for receipt of the piston rod. 
     
     
         19 . An actuator as set forth in  claim 18 , where the seal gland is separate from the sensor mount. 
     
     
         20 . An actuator as set forth in  claim 18 , where clearance between the sensor mount and the piston rod is less than clearance between the seal gland and the piston rod. 
     
     
         21 . An actuator as set forth in  claim 18 , where a wire lock provides a flexible connection between the seal gland and the sensor mount. 
     
     
         22 . An actuator as set forth in  claim 18 , where the sensor mount is connected to the cylinder housing with a retaining wire that forms a wire lock. 
     
     
         23 . An actuator as set forth in  claim 22 , where the flexible connection between the sensor mount and the cylinder housing is provided by ensuring sufficient clearances between the retaining wire, the seal gland, and the sensor mount. 
     
     
         24 . An actuator as set forth in  claim 16 , where the mount is made of a bearing material. 
     
     
         25 . An actuator as set forth in  claim 16 , where the mount includes a collar that defines a passage therethrough for receipt of the piston rod. 
     
     
         26 . An actuator as set forth in  claim 16 , where the mount includes a collar that extends around the piston rod 
     
     
         27 . An actuator as set forth in  claim 16 , where the sensor is an optical sensor. 
     
     
         28 . A method of providing a flexible connection for a sensor mounted on a piston-cylinder assembly comprising the steps of:
 a) separating an optical sensor mount assembly from a seal gland assembly,   b) providing less clearance between the sensor mount and a rod than the clearance between a seal gland and the rod,   c) providing a wire lock connection between the seal gland and sensor mount   d) building in sufficient clearances between the wire lock, seal gland, and sensor mount to allow ‘flex’ between the seal gland and sensor mount.