Machine vise with clamping force detector

A machine vise for clamping a workpiece between a stationary jaw and a movable jaw, comprising;

• a body having a stationary jaw fixed thereto;
• a movable member having a movable jaw fixed thereto, said movable member being movable relative to said body;
• a support portion formed on one of said body and said movable member;
• an internally threaded member fixed to the other of said body and said movable member;
• a feedscrew member rotatably supported by said support portion, and engaging said internally threaded member, for moving said movable member relative to said body by a rotating motion thereof, to clamp the workpiece between said stationary jaw of said body and said movable jaw of said movable member;
• said feedscrew member including a radially outwardly extending flange portion which prevents the feedscrew member from moving in an axial direction thereof relative to said support portion, due to a reaction force which is produced upon clamping of said workpiece by said rotating motion of said feedscrew member with said externally threaded portion thereof engaging said internally threaded member;
• and
• means for detecting an axial force exerted between said support portion and said flange portion of said feedscrew member, said detecting means being positioned there between and detecting an axial force which is exerted on said support portion via said flange portion and said detecting means due to said reaction force,
• said detecting means comprising a strain member which is susceptible to a compressive strain in said axial direction due to said axial force, and at least one strain gage attached to said strain member which generates an output signal indicative of said compressive strain of said strain member,
• said strain member consisting of a ring including an axially intermediate portion which has an annular groove in an inner surface thereof, and which has a plurality of cutouts formed in an outer surface thereof, said cutouts being parallel to an axis of said ring,
• whereby a clamping force of said workpiece is detected based on said output signal, according to a predetermined relation between said clamping force and said axial force.

A machine vise for clamping a workpiece between a stationary jaw and a movable jaw, comprising:

• a body having a stationary jaw fixed thereto;
• a movable member having a movable jaw fixed thereto, said movable member being movable relative to said body;
• a support portion formed on one of said body and said movable member;
• an internally threaded member fixed to the other of said body and said movable member;
• a feedscrew member rotatably supported by said support portion, and engaging said internally threaded member, for moving said movable member relative to said body by a rotating motion thereof, to clamp the workpiece between said stationary jaw of said body and said movable jaw of said movable member;
• said feedscrew member including a radially outwardly extending flange portion which prevents the feedscrew member from moving in an axial direction thereof relative to said support portion, due to a reaction force which is produced upon clamping of said workpiece by said rotating motion of said feedscrew member with said externally threaded portion thereof engaging said internally threaded member;
• and
• means for detecting an axial force exerted between said support portion and said flange portion of said feedscrew member, said detecting means being positioned there between and detecting an axial force which is exerted on said support portion via said flange portion and said detecting means due to said reaction force,
• said detecting means comprising a strain member which is susceptible to a compressive strain in said axial direction due to said axial force, and at least one strain gage attached to said strain member which generates an output signal indicative of said compressive strain of said strain member,
• said strain member comprising a ring including an axially intermediate portion which has an annular groove in an inner surface thereof, and which has a plurality of cutouts formed in an outer surface thereof, said cutouts being parallel to an axis of said ring,
• whereby a clamping force of said workpiece is detected based on said output signal, according to a predetermined relation between said clamping force and said axial force.