A turnbuckle, stretching screw or bottle screw is a device for adjusting the tension or length of ropes, cables, tie rods, and other tensioning systems. It normally consists of two threaded eye bolts, one screwed into each end of a small metal frame, one with a left-hand thread and the other with a right-hand thread.
Applications –
i) Aircraft- Turnbuckles have been used in aircraft construction, especially during the early years of aviation.
ii) Shipping- Turnbuckles are used for tensioning a ship's rigging and lashings. This device is also known as a bottle screw
iii) Sports- Turnbuckles find common use to tension the ropes in professional wrestling rings and boxing rings, where they serve as the attachment between the ring ropes and ring posts.
iv) Entertainment industry- Turnbuckles are used in nearly all rigging performed in the entertainment industry, including theatre, film, and live concert performances.
v) Pipe systems- Turnbuckles are used in piping systems as a way to provide minor adjustments for field inconsistencies.
vi) Orthopaedics- A type of splint is used for upper limb to produce gradual stretching over contracted joint by its turn buckle mechanism.
vii) Buffers and chain coupler
viii) Guy-wire
ix) Mechanical joint