Hook (device)
The hook is a curved or angularly curved device for hanging or hooking objects, usually made of metal, wood or plastic.
Basics
The hook is a rod that is used as a simple machine in such a way that self-locking occurs. To do this, it is sufficient to place one end of the rod against the direction of the force and block the other. Whatever is pulled over the hook locks into place as long as there is a force. For example, the nail in the wall works as a coat hook.
In most cases, however, the hook is - literally - curved.
The hook is subjected to bending and often tensile loads. The counterpart in a hook connection can be another hook or a ring implemented as an eye .
There are two ways to release the hook connection:
- Strain relief , the self-locking is released
- Overload until the moment bends the hook so far that the counterpart slides - this can be achieved:
Special forms
- Snap hook , closed by a resilient part to form an eye, in order to prevent the hook connection from loosening due to strain relief
- Angled hook , a rod bent at right angles or bent by a little more than 90 °
- Barbs , weapons or fishhooks
- Meat hook, an S-shaped curved rod with a pointed end for hanging soft objects on a bar
application
Hooks as tools, machine parts or other utilities
- Brummel hook : for the quick connection of cords in paragliding and lines in sailing
- Catch hook , a braking device on aircraft carriers
- Rock , ice , climbing or throwing hooks : as a safety device in climbing, for hammering in, screwing or throwing
- Fender hook , in sailing or shipbuilding a hook attached to a screw-on plate for hanging a fender
- Crochet hook
- Hook plow , the oldest form of the plow, without an iron ploughshare
- Releasing hook , a maritime term; some of these hooks can also be loosened under load
- Crane hook , actively to close to an eye and to open again
- Coat hooks
- Poker , an angle hook for controlling and cleaning a fireplace
- Screw hook with wood or metal thread for screwing on or screwing
- Storm hook , to secure moving parts of the building when strong wind forces occur, similar to a trailer coupling
- Trailer hook , in sailing or shipbuilding an eye that is firmly connected to a snap hook
Not a real catch
- The so-called "tow hook" for land vehicles is usually actually a towing eye
Hook with a push spur or push weapon with barbs
- Ango , a barbed spear
- Boat hook
- Epee breaker , a historical weapon that caught the blade of the opponent's weapon
- Tear hook
- Grappling hook
- in a broader sense: halberd
Advanced systems
Tricky arrangements of the hook are also simple machines in the sense of mechanics : they do work by changing the direction of forces or movements
- Hook and eye:
- the coupling, known from toy trains in the basic form of hook and eye , is more complex in the case of railroad and trailer coupling
- Velcro fastener , also a combination of hook and eye - a classic example of bionics
- Two hooks:
- Hook and corrugated wheel : a simple one-turn lock, with a spring-loaded hook as a ratchet
Natural examples
- the fang and the claw
- the hooks called burdock on the seed coats of various plants ( burdock , velcro grass )
To the origin of the word
The word hook is related to rake and hoe or hoe (as an ax) , this linguistic relationship primarily relates to the shape, but also to the extended mode of action: These two tools are also deflected wedges.
