# [Theory of Machines] Why is Belt in a Belt drive a Link

Hello every1...

I'm a mechanical enggineering student...
I've been studying theory of Machines...
My academic syllabus includes only "Simple Mechanisms"...
Now in Simple Mechanisms...the first thing we get to know is a "Kinematic Link"...

Definition of a Kinematic Link:-it is a rigid or resistant body having relative motion with respect to other link/elements of the machine/mechanism

But I just dont get how a belt in a belt drive[and chain in a chain drive ] is link...
because if I stand on a single part of a chain I'll find the other parts moving[except for the ones in a straight line moving in a particular direction]...and these individual parts of the chain together form a chain[same should apply for belt drive...with a very large number of individual parts..I think]
Moreover I also dont get how Belt-pulley forms a higher pair...

Lastly is it a part of "Complex Mechanisms"...
Plz help me ...
any ideas on this are welcome...
Thanxxxx

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Any Idea...anyone...??
Any ideas are welcome...Please do post if you have any idea...

Have I posted it in the Wrong section..and so not getting any help??
Which section should I post it in??
[Actuall I found "Conceptual evaluations" as tag for the sub section title ... and so posted it here]

Sorry..for bumping...

Belt/chain drive is not regarded as a single link, they make what is known as a higher pair, & it is considered as an equivalent to two lower pairs(or kinematic link).

Belt pulley is a higher pair because it has line contact & no slippage(ideally)

Belt/chain drive is not regarded as a single link, they make what is known as a higher pair, & it is considered as an equivalent to two lower pairs(or kinematic link).

Belt pulley is a higher pair because it has line contact & no slippage(ideally)
Thanxx...
Belt/chain drive is not regarded as a single link
That did solve my confusion...
and
ya..they do make a higher pair...
But can u tell me where can I find[or can u give/write] me a document which explains how the "Chain-Sproket" Kinematic pair results in a constrained motion with a single Degree of Freedom...

any help appreciated...

But can u tell me where can I find[or can u give/write] me a document which explains how the "Chain-Sproket" Kinematic pair results in a constrained motion with a single Degree of Freedom...
what are the possible relative motions between a chain & a sprocket?

Hint: chain cannot slip on the sprocket