Why is double helix structure of DNA important?

Answer 1

#Herringbone gears are a type of double helical gear, meaning that they have both a left hand and right hand element to cancel thrust or side loading on their bearings. A true herringbone has a 30° helix angle, 20° transverse pressure angle, and an AGMA stub whole depth factor. They may have a center groove between the two hands, but this is not absolutely necessary. Herringbone gears are cut on specialized machines that cut both hands at the same time, precisely locating the apex of the two helixes.

#The double helical form balances the inherent thrust forces.

[Double helical gears, invented by André Citroën and also known as herringbone gears, overcome the problem of axial thrust presented by 'single' helical gears by having teeth that set in a 'V' shape. Each gear in a double helical gear can be thought of as two standard, but mirror image, helical gears stacked. This cancels out the thrust since each half of the gear thrusts in the opposite direction. They can be directly interchanged with spur gears without any need for different bearings.

Where the oppositely angled teeth meet in the middle of a herringbone gear, the alignment may be such that tooth tip meets tooth tip, or the alignment may be staggered, so that tooth tip meets tooth trough. The latter type of alignment results in what is known as a Wuest type herringbone gear.

With the older method of fabrication, herringbone gears had a central channel separating the two oppositely-angled courses of teeth. This was necessary to permit the shaving tool to run out of the groove. The development of the Sykes gear shaper now makes it possible to have continuous teeth, with no central gap.]

#Double helical gears give an efficient transfer of torque and smooth motion at very high rotational velocities.

#A disadvantage of herringbone gears is the high cost due to special gear shaping equipment and special cutting tools.

-Also during assembling a gear box ,aligning is to be given special attention

Answer 2

It is ideal for the replication of DNA, The double helix is also formed by antiparallel strands of DNA.