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Links
Concept sheet | Science and Technology
What Is a Link?
- A link is the basic mechanical function that connects different parts of a technical object.
- A linking component is an intermediate part that is sometimes needed to connect other parts.
Links and linking components can be shown in an object’s construction diagram.
Construction Diagram of a Pair of Scissors
Construction Diagram of a Pen
What Are the Types of Links?
The parts of a technical object can be linked in several ways.
Some of these types are determined by the motions they allow or limit between linked parts.
The main types of links are listed below.
Embedded link
Possible motion : none
Advantages | Disadvantages |
|---|---|
| Stable connection that can withstand heavy loads | May cause deformation of parts |
K-FK, Shutterstock.com
Embedded or fixed links are used to assemble the structure of railway bridges.
Pivot link
Possible motion : rotation along a single axis
Advantages | Disadvantages |
|---|---|
| Generally simple to design | May require lubrication |
Door hinges are linking components that enable a pivot link.
Slide link
Possible motion : rectilinear translation along a single axis.
Advantages | Disadvantages |
|---|---|
| Controls the amplitude of translational motio | Requires high machining precision |
| Can support heavy loads | May require lubrication |
The runners attach the drawer to the cabinet, while allowing the translational motion required to open and close it.
Sliding pivot link
Possible motion : independent or simultaneous rotation and rectilinear translation along the same axis.
Advantages | Disadvantages |
|---|---|
| Generally simple to design | May require lubrication |
| Requires high machining precision |
The rods on which the foosball figures are mounted are connected to the game table by a sliding-pivot link.
Helical link
Possible motion : helical along a single axis.
Advantages | Disadvantages |
|---|---|
| Transforms rotation into rectilinear translation | May require lubrication |
| Requires high machining precision |
A helical link between the clamping screw and the clamp frame allows the screw to translate as it rotates.
Ball-joint link
Possible motion : rotation along several axes.
Advantages | Disadvantages |
|---|---|
| Great freedom of movement | May require lubrication |
The ball joint link that connects the handle and base of a video game controller allows the handle to move along several different axes.
Planar link
Possible motion : rectilinear translation along one plane and rotation around an axis that is perpendicular to the same plane.
Advantages | Disadvantages |
|---|---|
| Very stable due to a large contact surface | High friction |
The planar link that connects the mouse to a table allows rectilinear translation along the table’s plane as well as rotation around an axis perpendicular to the table’s plane.