What are locating devices?
Locating devices are the components that are used to quickly and easily position (or locate) the part with respect to the workpiece.
With the help of locating devices, the parts can be set up quickly and hence the machining can be done easily and quickly.
On the basis of nature of surface to be located, Locating devices are classified as;
- Plane locators
- Concentric locators
- Radial locators
Plane locators are used to locate flat parts.
Concentric locators are used to locate the workpiece from its axis. (For example, locating pins placed in a hole).
Radial locators are the locators which restrict the movement of a workpiece around a locator.
Types of locating devices
There are different types of locating devices in jig and fixture, as mentioned below.
- Flat locator
- Cylindrical locator
- Conical locator
- Jack pin locator
- Drill bush locator
- V locator
- Cylindrical locators in combination
- Outside pin locators
Let’s see each of these locating devices one by one.
#1) Flat locator
Flat locators are used for positioning of flat surface of the components.
The first image shows the workpiece is placed directly on the jig having a clearance.
The second and third image shows the button type locators which are fitted in a jig body.
#2) Cylindrical locator
Cylindrical locators are used for positioning parts that have drilled holes in it.
The cylindrical locator is fitted on a jig body as shown in the above image.
After this, the workpiece is inserted from the top so that it is positioned exactly where it is required.
To provide the clearance, the undercut is made on the jig body.
#3) Conical locator
The conical locator is shown in the above image.
The conical locators are used to position the workpieces that have drilled holes.
The conical locators have a capacity to accomodate a slight variation in surface texture of several components.
#4) Jack pin locator
Jack pin locator is used to support the rough workpiece from the bottom during its locating procedure.
In jack pin locator, the pin height can be adjusted to fit the variations in surface texture.
#5) Drill bush locator
Drill bush locators are used to position the workpieces that are cylindrical in shape.
For easy location purposes, the drill bush is provided with a conical opening and sometimes it is screwed on a jig body to get the adjusted height of the workpiece.
Also it provides a guide way to the tool.
#6) V locator
The V locator is used to locate the workpiece that has a circular or semi circular profile.
The V block should be used correctly such that the workpiece size does not affect its location (see above image).
The V block shown in the above image can also be used as a clamping device.
This can be done by using two V blocks, one fixed and other sliding.
The sliding V blocks can be moved by hand screw as shown in the image below.
#7) Cylindrical locators in combination
In the above image, you can see the diamond pin for the radial location.
The pin A shown in the above image arrests 5 degree of freedom while pin B will arrest the 6th degree of freedom.
The length of pin A is slightly more than pin B so that the workpiece can be located on pin A, and then it is rotated to locate pin B.
#8) Outside pin locators
Outside pin locators are used to locate the workpiece that has an irregular (or odd) profile.
The pins are arranged on a jig body following the outside profile of the workpiece as shown in the above image.