Centering process in chucking work and apparatus therefor

Abstract

A process and apparatus for centering accurately and speedy a workpiece on a magnet chuck mounted on a work spindle. A pair of action pads spaced away from one another comes into engagement with the workpiece attracted to the work spindle, thereby performing the centering operation. The action pads are mounted on a support plate that can freely turn on a fulcrum. As the fulcrum makes head towards a rotational center of the magnet chuck, the action pads comes into abutment in a rocking manner against the workpiece that is held at off-center relation in the chuck, thereby compensating the off-center relation to keep a center of the workpiece in alignment with the rotational center of the chuck.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a turning machine equipped with a centering apparatus according to the present invention:

FIG. 2 is a schematic fragmentary view in perspective of a centering tool for the centering apparatus of FIG. 1:

FIG. 3 is a schematic view in perspective showing a workpiece attracted magnetically to a turret after having been centered using the centering apparatus:

FIG. 4 is a view in front elevation of the centering tool for the centering apparatus of FIG. 1:

FIG. 5 is a plan view of the centering tool of FIG. 4:

FIG. 6 is a view in side elevation of the centering tool of FIG. 4:

FIGS. 7(A) to 7(C) are illustrations explanatory of how a workpiece is centered by the centering tool of FIG. 1, in which the (A) shows a phase the workpiece is set off-center or lopsided towards any one side, the (B) shows another phase the workpiece is lopsided towards other side, and the (C) is a further another phase the workpiece is free of the lopsided condition:

FIG. 8 is a diagram illustrating inspection results of circularity and coaxiality measured in the workpiece after centered by the centering apparatus of FIG. 1: and

FIG. 9 is a diagram illustrating inspection results of circularity and coaxiality measured in the workpiece after centered by the conventional centering apparatus of FIG. 1.

Claims

1. A process for centering a workpiece attracted on a chuck mounted on a work spindle, using a centering tool comprising a support block and a pair of action pads lying on the support block with spaced away from one another in a way coming into engagement with a circular part of the workpiece; wherein the support block of the centering tool is supported to turn on a fulcrum; and wherein as the fulcrum of the support block moves head towards a rotational center of the chuck, the support block makes a rocking motion on the fulcrum in a way the action pads come into abutment from any one side against the workpiece that is held at off-center relation in the chuck, thereby compensating the off-center relation to keep a center of the workpiece in alignment with the rotational center of the chuck.

2. A process for centering a workpiece, as set forth in claim 1, wherein the chuck is a magnet chuck equipped on a machine tool to attract a cylindrical workpiece thereon and wherein the action pads is made to rise above the support block to come into either an outside or an inside circular surfaces of the workpiece, performing a centering operation of the workpiece on the chuck.

3. An apparatus for centering a workpiece; comprising a pair of action pads adapted to come into engagement with a circular part of the workpiece attracted to a chuck, a support block of the centering tool having mounted the action pads thereon in a fashion the action pads are spaced away from one another, and a moving part to bear the support block for free turning on a fulcrum of the support block; and wherein as the moving part gets the fulcrum of the support block moving head towards a rotational center of the chuck, the action pads alternately come into engagement from any one side against the workpiece that is held at off-center relation in the chuck, thereby compensating the off-center of the workpiece to bring a center of the workpiece in alignment with the rotational center of the chuck.

4. An apparatus for centering a workpiece, as set forth in claim 3, wherein the chuck is a magnet chuck equipped on a machine tool to attract a cylindrical workpiece thereon and wherein the action pads is made to rise above the support block to come into either an outside or an inside circular surfaces of the workpiece, performing a centering operation of the workpiece on the chuck.

5. An apparatus for centering a workpiece, as set forth in claim 3, in which the centering tool includes a support plate for the support block, a pair of action pads made in a fashion raised above the support plate, a shank having fastened to the moving holder and mounted the support plate to provide a fulcrum on which the support plate is allowed to turn freely, and a stopper fastened to the shank so as to came into abutment against recessed edges that are in opposition to one another on both sides of the stopper.

6. An apparatus for centering a workpiece, as set forth in claim 5, wherein the moving part having fastened the shank extending out of the support block of the centering tool is a holder mounted on a turret equipped on a machine tool.