Tail stock for a long vertically suspended workpiece that will experience heat expansion

Abstract

A tailstock for supporting a workpiece along a vertical rotary axis includes a base member, and a housing having a wall including a first end, and a second end, an outer surface, and an inner surface defining a central passage extending between the first and second ends defining a longitudinal axis. The second end is coupled to the base member. A workpiece support extends through the central passage. The workpiece support includes a first end, a second end and an intermediate portion extending therebetween. A linear bearing is coupled to the base member in the central passage. The linear bearing slideably receives the second end of the workpiece support. A displacement sensor assembly includes a stationary portion mounted relative to one of the base member and the housing, and a moveable portion mounted to the second end of the workpiece support.

1 . A tailstock for supporting a workpiece along a vertical rotary axis comprising:
 a base member;   a housing having a wall including a first end, and a second end, an outer surface, and an inner surface defining a central passage extending between the first and second ends defining a longitudinal axis, the second end being coupled to the base member;   a workpiece support extending through the central passage, the workpiece support including a first end, a second end and an intermediate portion extending therebetween;   a linear bearing coupled to the base member in the central passage, the linear bearing slideably receiving the second end of the workpiece support; and   a displacement sensor assembly including a stationary portion mounted relative to one of the base member and the housing, and a moveable portion mounted to the second end of the workpiece support.   
     
     
         2 . The tailstock according to  claim 1 , further comprising: a rotating member mount coupled to the first end of the workpiece support. 
     
     
         3 . The tailstock assembly according to  claim 2 , further comprising: a biasing member arranged between the rotating assembly support and the linear bearing, the biasing member establishing a preload on the rotating assembly member. 
     
     
         4 . The tailstock assembly according to  claim 3 , wherein the biasing member comprises a coil spring. 
     
     
         5 . The tailstock assembly according to  claim 2 , further comprising: a shield member slidable mounted at the first end of the housing about the rotating assembly mount, the shield member including a first end portion, a second end portion, and an intermediate portion extending therebetween. 
     
     
         6 . The tailstock assembly according to  claim 5 , further comprising: a cap member provided at the first end portion of the shield member, the cap member supporting a bearing. 
     
     
         7 . The tailstock assembly according to  claim 6 , wherein the bearing comprises a Graphalloy® linear bearing. 
     
     
         8 . The tailstock assembly according to  claim 6 , wherein the bearing comprises a tapered roller bearing. 
     
     
         9 . The tailstock assembly according to  claim 8 , wherein the tapered roller bearing includes a first bearing element arranged at a first surface of the cap member and a second bearing element arranged at a second, opposing surface of the cap member. 
     
     
         10 . The tailstock assembly according to  claim 6 , further comprising: a rotating member rotatable operatively coupled to the rotating member mount through the cap member. 
     
     
         11 . The tailstock assembly according to  claim 10 , further comprising: a support sleeve arranged between the rotating member and the cap member. 
     
     
         12 . The tailstock assembly according to  claim 10 , wherein the rotating member comprises a stainless steel cone. 
     
     
         13 . The tailstock assembly according to  claim 1 , wherein the linear bearing includes a plurality of internal splines that cooperate with external splines provided on the workpiece support, wherein the linear bearing constrains relative rotation of the workpiece support. 
     
     
         14 . A method of supporting a rotating member of a tailstock comprising:
 rotating a rotating member coupled to a workpiece support slidably mounted in a housing of the tailstock;   vertically displacing the rotating member along a longitudinal axis in a first direction; and   measuring an amount of vertical displacement of the rotating member.   
     
     
         15 . The method of  claim 13 , wherein measuring the amount of vertical displacement includes directing a laser displacement sensor mounted to the housing at a target mounted to the workpiece support. 
     
     
         16 . The method of  claim 13 , further comprising: biasing the rotating member along the vertical axis toward a second direction opposite the first direction. 
     
     
         17 . A method of processing a workpiece comprising:
 supporting the workpiece on a tailstock extending along a vertical axis;   thermally processing the workpiece with a processing device; and   vertically displacing a portion of the tailstock assembly resulting from thermal expansion of the workpiece.   
     
     
         18 . The method of  claim 16 , wherein supporting the workpiece includes mounting the workpiece on a rotating member coupled to a workpiece support. 
     
     
         19 . The method of  claim 17 , wherein vertically displacing the portion of the workpiece includes vertically shifting the workpiece support. 
     
     
         20 . The method of  claim 16 , further comprising: sensing an amount of vertical displacement of the workpiece through a displacement sensor. 
     
     
         21 . The method of  claim 19 , further comprising: vertically displacing the processing device based on the amount of vertical displacement of the workpiece.