LOCATING & CLAMPING DEVICESLOCATING & CLAMPING DEVICES

IN JIGS & FIXTURESIN JIGS & FIXTURES

BY BY

DINBANDHUDINBANDHU

INTRODUCTIONINTRODUCTION

Production work-holding devices Production work-holding devices used to manufacture duplicate parts used to manufacture duplicate parts accurately. accurately.

PURPOSEPURPOSE

To make a correct relationship To make a correct relationship between the cutter, tool and work between the cutter, tool and work piece.piece.

DEFINATION DEFINATION

FIXTUREFIXTURE::

Locates and clamps the Locates and clamps the work piece.work piece.

JIGJIG: :

Locates & clamps the Locates & clamps the work piece and guides the cutting work piece and guides the cutting tool.tool.

ELEMENTS OF JIGS & FIXTURESELEMENTS OF JIGS & FIXTURES

Locating ElementsLocating Elements

Clamping ElementsClamping Elements

Tool Guiding and Setting ElementsTool Guiding and Setting Elements

LOCATIONLOCATION

Location refers nothing but the position, Location refers nothing but the position, used to establish a desired relationship used to establish a desired relationship between the work piece & work-holding between the work piece & work-holding devices.devices.

Correct location provides a good accuracy.Correct location provides a good accuracy.

Locating points are directly proportional to Locating points are directly proportional to D.O.F.D.O.F.

3-2-1 PRINCIPLE3-2-1 PRINCIPLE

3-2-1 PRINCIPLE3-2-1 PRINCIPLEPINSPINS

RESTRICTEDRESTRICTED

3 PINS 5 DOF3 PINS 5 DOF

2 PINS 3 DOF2 PINS 3 DOF

1 PIN1 PIN 1 DOF1 DOF

6 PINS 9 DOF6 PINS 9 DOF

3-2-1 PRINCIPLE CONTD…..3-2-1 PRINCIPLE CONTD…..

3 pins are inserted at base plane3 pins are inserted at base plane 2 pins are inserted at vertical plane2 pins are inserted at vertical plane 1 pin in third plane positively locates part1 pin in third plane positively locates part

Thus, its also known as “Six Point Locating Thus, its also known as “Six Point Locating Principle”Principle”

LOCATING DEVICESLOCATING DEVICES PIN LOCATORPIN LOCATOR::

A round pin is used to hold the A round pin is used to hold the workpiece in position. workpiece in position.

Pins are longer in length & used Pins are longer in length & used for horizontal location. for horizontal location.

FLAT LOCATORSFLAT LOCATORS::

Used for locating flat machined Used for locating flat machined faces of the component.faces of the component.

Fig(3) has better arrangement than Fig(3) has better arrangement than Fig(2) due to its capacity to take and Fig(2) due to its capacity to take and load for having provision of swarf load for having provision of swarf clearance.clearance.

DIAMOND PIN LOCATORDIAMOND PIN LOCATOR:: Used to constrain pivoting of the

workpiece around principle locator. The principle locator should be longer than diamond pin.

CYLINDRICAL & SPHERICAL CYLINDRICAL & SPHERICAL LOCATORSLOCATORS::

Unlike with cylindrical Unlike with cylindrical locators,locators,

Spherical locators are Spherical locators are impossible impossible to bind due to to bind due to the same distance the same distance between the opposite side of the between the opposite side of the

contact area. contact area.

VEE BLOCK LOCATORSVEE BLOCK LOCATORS::

Mainly used to locate round shafts & Mainly used to locate round shafts & cylindrical workpieces.cylindrical workpieces.

Its having advantage of centralizing Its having advantage of centralizing feature.feature.

CLAMPINGCLAMPING

Require to hold the workpiece Require to hold the workpiece against the cutting forces.against the cutting forces.

PrinciplesPrinciples:: 1.Position1.Position 2.Strength2.Strength 3.Productivity3.Productivity 4.Operator fatigue4.Operator fatigue 5.Workpiece variation5.Workpiece variation

CLAMPING DEVICESCLAMPING DEVICES SCREW CLAMPSCREW CLAMP: :

Widely used for jigs & fixtures , Widely used for jigs & fixtures , offers the tool offers the tool designer almost designer almost unlimited application potential unlimited application potential lower costs & less complex designs.lower costs & less complex designs.

Used to grip the workpiece on its Used to grip the workpiece on its edgesedges..

STRAP CLAMP:STRAP CLAMP:

Simplest and most commonly Simplest and most commonly used clamp. o used clamp. o Also known as lever clamp, made of Also known as lever clamp, made of

rectangular platesrectangular plates

WEDGE CLAMP:WEDGE CLAMP:

The horizontal The horizontal movement of movement of wedge wedge causes upward vertical causes upward vertical clamping force on workpiece.clamping force on workpiece.

CAM CLAMP:CAM CLAMP:

Quick acting clamp which Quick acting clamp which is is extensively used extensively used in jigs & fixtures due in jigs & fixtures due to its to its rapid & convenient action.rapid & convenient action.

SWING PLATE CLAMPSWING PLATE CLAMP::

Employed for quick loading & Employed for quick loading & unloading of light workpieces.unloading of light workpieces.

The clamp is operated by swinging The clamp is operated by swinging the plate in position and locking it by the plate in position and locking it by turning the screw which passes through turning the screw which passes through its center. its center.

TOGGLE CLAMPTOGGLE CLAMP::

Quick acting clamp & its Quick acting clamp & its operation depends upon the operation depends upon the movement of rigid link.movement of rigid link.

Widely used for holding sheet Widely used for holding sheet metal parts in position.metal parts in position.

PIVOTED CLAMPPIVOTED CLAMP::

Clamp is pivoted at the center Clamp is pivoted at the center to simplify the operation.to simplify the operation.

Eliminates the use of spanner Eliminates the use of spanner for clamping.for clamping.

REFRENCESREFRENCES

Jig & Fixture Design by Edward G. Jig & Fixture Design by Edward G. HoffmanHoffman

Jigs & Fixtures by Joshi P.H.Jigs & Fixtures by Joshi P.H. IIT IIT Kharagpur Notes on Jigs & Notes on Jigs &

FixturesFixtures Images from GoogleImages from Google Workshop Technology-II by Hajra Workshop Technology-II by Hajra

ChoudharyChoudhary

THANK UTHANK U