What is this part for in VCRs ?
 

I haven't found a different/better place in the forum to post this post - hope this is the right one.

This part marked in the red box(photos are attached to this post) most likely comes from the VCR: JVC HR-S7711, but it is also probably in, for example: JVC HR-S7722 or Philips VR 20D(clone of: JVC HM-DR10000 ?).

What is it for ? What does it do - how does it work ? Is it useful or is it better to remove it ?

If I good know(remember) the tape runs over that white roller, and I guess the whole part of this part can go up and down. Maybe it is part of the equipment of this device working for: "tracking", because it is probably not a Dynamic Drum System as far as I know(it(DDS) is probably from the bottom of the drums) ?

It's a tape tension/tape speed dampener, The inertia of the weight acts as a load which helps put some tension on the tape before it enters the drum so it will have a better head to tape contact. Don't remove it, A lot of people think it's useless but it is not.

Thank you for your answer and information. :)