How many links make up a pantograph mechanism___________________?
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Answer: A. lower pairs
Explanation
A pantograph mechanism is a linkage system used to reproduce drawings or motions at different scale proportions. All movable joints connecting the rigid links of a pantograph allow relative rotation around fixed pivot pins. These pivoting pin joints are classified kinematically as lower pairs because they involve surface contact between links. Kinematic pairs are classified as lower pairs when two elements have surface contact, such as pin joints and sliding blocks. A pantograph consists of a parallelogram linkage where all connecting joints are traditional turning or revolute pairs. Grashof conditions and mobility equations confirm that a standard pantograph operates with four lower turning pairs.
Higher pairs involve point or line contact, such as gear teeth meshing or cam followers rolling on surfaces, unlike pantograph pins. Rolling pairs involve pure rolling motion without slipping, which is not the primary joint type in a pantograph. Turning pairs and spherical pairs describe specific joint freedoms, but lower pairs is the broad kinematic category requested.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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