Opening/closing chuck and method of manufacturing fingers

Abstract

A finger includes a pair of overhanging portions that project out laterally from a main body portion. Outer peripheral surfaces of the overhanging portions are made up from five surfaces including upper surfaces, side surfaces, lower surfaces, first end surfaces, and second end surfaces. Crowning is applied to the intersections between these surfaces.

What is claimed is: 
     
         1 . An opening/closing chuck comprising a pair of fingers configured to slide inside of a guide groove of a body, and which are slidably supported in directions to approach toward and separate away from each other;
 wherein the fingers each include a pair of overhanging portions configured to project out laterally from a main body portion, outer peripheral surfaces of the overhanging portions are made up from five surfaces including upper surfaces, side surfaces, lower surfaces, first end surfaces, and second end surfaces, and crowning is applied to intersections between these surfaces.   
     
     
         2 . The opening/closing chuck according to  claim 1 , wherein the upper surfaces and the lower surfaces are perpendicular to the side surfaces. 
     
     
         3 . The opening/closing chuck according to  claim 1 , wherein the upper surfaces and the lower surfaces are tapered surfaces configured to come into closer proximity to each other toward the side surfaces. 
     
     
         4 . The opening/closing chuck according to  claim 1 , wherein, in the guide groove of the body, crowning is applied to an intersection between a wall surface facing toward the upper surfaces and a wall surface facing toward side surfaces of the main body portion. 
     
     
         5 . The opening/closing chuck according to  claim 1 , wherein crowning is applied to a location where stepped portions in the guide groove face toward the lower surfaces. 
     
     
         6 . The opening/closing chuck according to  claim 3 , wherein the overhanging portions include recesses centrally in the longitudinal direction of the upper surfaces, the side surfaces, and the lower surfaces, together with crowning regions at both ends of the recesses, and grease reservoirs open on bottom surfaces of the recesses. 
     
     
         7 . A method of manufacturing a pair of fingers configured to slide inside of a guide groove of a body of an opening/closing chuck, and which are slidably supported in directions to approach toward and separate away from each other;
 wherein the fingers each include a pair of overhanging portions configured to project out laterally from a main body portion, and outer peripheral surfaces of the overhanging portions are made up from five surfaces including upper surfaces, side surfaces, lower surfaces, first end surfaces, and second end surfaces, wherein the upper and lower surfaces are perpendicular to the side surfaces;   the method of manufacturing the fingers comprising a step of applying crowning at intersections of the five surfaces, by a combination of performing grinding with respect to the side surfaces by a first machining tool, and performing grinding with respect to the upper surfaces and the lower surfaces by a second machining tool.   
     
     
         8 . A method of manufacturing fingers configured to slide inside of a guide groove of a body of an opening/closing chuck, and which are slidably supported in directions to approach toward and separate away from each other;
 wherein the fingers each include a pair of overhanging portions configured to project out laterally from a main body portion, outer peripheral surfaces of the overhanging portions are made up from five surfaces including upper surfaces, side surfaces, lower surfaces, first end surfaces, and second end surfaces, and the upper surfaces and the lower surfaces are tapered surfaces configured to come into closer proximity to each other toward the side surfaces;   the method of manufacturing the fingers comprising a step of applying crowning at intersections of the five surfaces, by performing grinding with respect to the side surfaces and simultaneously performing grinding with respect to the upper surfaces and the lower surfaces, using a single machining tool.   
     
     
         9 . The method of manufacturing the fingers according to  claim 8 , wherein:
 the overhanging portions include recesses centrally in the longitudinal direction of the upper surfaces, the side surfaces, and the lower surfaces, together with crowning regions at both ends of the recesses, and grease reservoirs open on bottom surfaces of the recesses; and   by the step, crowning of the crowning regions is applied.