Pliers
A pair of pliers (from the Old High German zanga : 'pliers', 'bitchess'; related to the Greek dáknein = 'bite') is a two-legged tool in which the active points ( gripping jaws , cutting edges , etc.) act in opposite directions on the workpiece, fixing or processing. In contrast to scissors, however, these do not slide past each other.
In modern times, pliers are forged from alloyed and unalloyed tool steels . For simple pliers, unalloyed tool steels with a carbon content of 0.45% are used. Higher quality and more heavily stressed pliers are made of materials with a higher carbon content and / or alloy elements such as chromium or vanadium .
Pliers usually consist of three areas: handles, joints , technically referred to as trade and pliers head (with the points of action). Such joint pliers work according to the lever principle : Two bilateral levers are connected to one another by a joint. As a rule, the handles form the longer lever arms (= force arm), the shorter lever arms (= load arm) form the pliers head. According to the law of levers, the manual force applied to the handles is converted to shorten the path and transferred to a workpiece by means of the pliers head. The force in the jaws, which perform a grip-like movement when the legs are pressed together, increases with the transmission ratio. In the case of pliers with which large forces are to be generated, the distance from the center of the pivot pin to the handle must therefore be large and the distance from the center of the pivot pin to the gripping jaws or cutting edges must be as small as possible.
Different from the basic type of pliers, there are special shapes, some of which are also widely used, such as the grip pliers based on the toggle-lever principle .
history
The oldest pliers were probably used to grip and move hot objects (coal, crucibles , forgings, etc.) and, like the oldest (Egyptian) type of pliers, were probably constructed on the principle of tweezers . Joint pliers have been known since ancient Greece. The earliest known depictions include Greek vase paintings showing tongs as an attribute of the Greek god of smith and fire, Hephaestus .
The differentiation of the craft branches, but especially the accelerated technical development in modern times (mechanization, motorization, expansion of electrical engineering, electronics and telecommunications, etc.) repeatedly required new types of pliers. The latest developments include special pliers for processing fiber optic cables .
technical features
In contrast to other hand tools, pliers are not designed for a specific task (such as hammers , drills , screwdrivers , saws , etc.). Their variety is therefore almost unlimited.
According to ISO 5743, pliers with cutting edges should have a hardness of at least 55 HRC on the cutting edge , and at least 42 HRC on the gripping surface of the pliers head. In addition, they should bear the manufacturer's brand or the supplier's name.
Classification according to purpose
Basic types of pliers are:
- Pliers for shaping / reshaping, such as crimping pliers , round nose pliers, blind riveting pliers
- cutting / separating pliers, such as side cutters, bolt cutters, punch pliers, wire stripping pliers, pincers
- Gripping / holding pliers such as the magnifying glass pliers such as circlip pliers , pipe wrenches, water pump pliers , grip pliers
- combined pliers, such as combination pliers
Multi-function tools often have pliers as a central element
Pincer joints
Depending on the application and quality of the pliers, a distinction is made between several types:
- the applied trade, the basic shape of the pincer joint, in which the pincer legs are simply placed on top of each other and connected to the hinge pin and
- the pushed through trade, in which one leg of the pliers is passed through an opening in the other leg.
- With some articulated tongs (e.g. grill tongs ), the legs are elastically connected to one another at one point, so that they have to be pressed together to grip.
Push-through joints are difficult to manufacture, but guidance in the joint is still given if the joint pin has greater play due to wear. Thrust trades are therefore mostly for fine mechanical precision pliers, especially side cutters, but also z. B. used for water pump pliers and other adjustable pliers.
Handles
There are numerous types of handles that pliers are equipped with:
- Uncoated, smooth handles are inexpensive and particularly suitable for regular cleaning and disinfection as well as in environments where the handle material would not withstand the heat (forge, glass production)
- Uncoated handles with a surface structure make it easier to hold on
- Plastic-coated handles are inexpensive and only enlarge the grip of the pliers to a small extent, but improve the gripping security compared to uncoated surfaces
- Multi-component handles are made of plastics with different elasticities in order to work ergonomically and over the long term with the pliers or to reduce impact loads. These handles can be colored, for example as a trademark of the manufacturer or to visually represent certain properties.
- One-component handles are somewhat simpler versions of the multi-component handles
- ESD handles are common in electronics when electrostatic charges can damage the product. The handle has a very low conductivity to allow static charges to flow away.
- VDE handles are insulated up to a specified voltage level so that no noticeable current flows when touching dangerous lines (phase). The head of the pliers is also partially insulated in order to avoid short circuits by touching live parts.
Eyelets on handles are used for fall protection, for example when working at great heights.
Pliers for manual work
The most common types of pliers include:
- Electronics pliers - smaller versions of different pliers for fine work, often combination and needle-nose pliers as well as side cutters
- Flat nose pliers - gripping and holding pliers for sheet metal and other flat objects
- Gripping pliers , gripping aid - as an extended arm for gripping objects on the floor without bending down deeply
- Grip pliers - adjustable gripping and holding pliers, for clamping and automatically holding objects
- Pincers - primarily for gripping nail heads and pulling out the nail by rolling the pliers over their rounded jaws
- Combination pliers, combination pliers - in addition to the flat, the jaws also have a transversely concave area for gripping round material; often also equipped with side cutting edges
- Monierzange ( Rabitz- , Flechter- , Rodel pliers for twisting the wire, as for joining -) reinforcing iron to be able to cut through the steel concrete construction, usually formed as an extension of pincers around the wire following the same; the wire twisting pliers are available for finer wires
- Pipe wrench - heavy gripping pliers for holding and powerfully turning ( threaded ) pipes; In contrast to the lighter water pump pliers, mostly continuously adjustable
- Round-nose pliers (also known as jewelry bending pliers) - similar to needle-nose pliers with round jaws for forming wire eyelets and cylindrical metal strips
- Blacksmith tongs - extended gripping or pincers for holding glowing metal parts in the forge and on the anvil
- Circlip pliers - for inserting and removing of retaining rings
- Needle- nose pliers (also needle nose pliers ) - straight and cranked, also known as cranesbill pliers ; flat-nosed pliers with elongated jaws that narrow at the front and are mostly rounded at the back; often used for gripping wire and electronic components
- Water pump pliers - technical name for the most frequently used pliers with a wide adjustment range; for gripping objects that are too big for the combination pliers, and for lighter work as a replacement for the heavy pipe wrench
Pliers for cutting through materials
- Wire stripping pliers - different designs that cut into the outer cable insulation in order to be able to pull it off
- Bolt cutters - heavy, mostly geared pliers for cutting through metal parts up to approx. 20 mm in diameter
- Wire cutters - side cutters with cutting edges angled or rounded lengthways to the cutting edge in order to fix the steel cable when cutting
- Cable cutter - side cutter with cutting edges angled or rounded lengthways to the cutting edge in order to fix soft round material when cutting through
- Hole punch pliers - for punching holes in soft material such as leather, textiles and cardboard
- Center cutter - a smaller, more handy form of bolt cutter, with or without leverage
- Pipe cutting pliers - usually has a single blade that cuts through plastic pipe with or without additional transmission (and ratchet mechanism ) that is positioned by the other, angled and wider jaw
- Side cutter - for cutting wire and soft flat material
- End cutter - similar to pincers with better leverage; can be used like a side cutter with cutting edges transverse to the longitudinal axis
Special pliers
- Bending pliers - for bending pipes and metal profiles
- Wire twisting pliers, Tying pliers - for twisting fine wires, e.g. for screw locking or sealing
- Core pliers - for removing the drill core remaining in the drill hole during core drilling
- Piston ring pliers - for applying the outwardly expanding piston rings in order to insert the piston into the cylinder
- Parrot tongs - for processing ceramic tiles
- Balancing weight pliers (balancing pliers, weight pliers) - for clamping balance weights to wheel rims
- Conductor's pliers - for punching and marking paper
- hydraulic tongs
- Hydraulic rescue set - for freeing jammed and buried people
- Demolition or demolition pliers - for cutting up reinforced concrete components
- Harbor tongs - for lifting crucibles in glass production
Medical forceps
A special type are forceps for medical purposes. They are also available in a wide variety of shapes. As a rule, they are made of low-corrosion steel (to reduce corrosion during sterilization ). Examples are swab forceps and umbilical cord forceps . Furthermore, there are so-called extraction forceps in dental surgery , which in their current form go back to John Tomes (1815–1895). There are different pliers for the different positions, types and sizes of teeth. In obstetrics serve forceps for vaginal surgical termination of birth .
Pliers for household use
Housekeeping pliers are mainly found in kitchen tools , cutlery and service cutlery . Examples of such pliers are:
- Ice tongs
- Pastry tongs
- Grill tongs
- Lobster tongs
- Snail tongs
- Spaghetti pliers
- Asparagus holder, tongs
- Tea tongs
- Sugar tongs
Tong-like devices are certain forms of the nutcracker and the tea-egg spoon.
literature
- Ingo Heindel , Roland Schuhmann : pliers . In: Reallexikon der Germanischen Altertumskunde . No. 34 . de Gruyter, Berlin / New York 2007, ISBN 978-3-11-018389-4 , pp. 422-430 .
- Franz Maria Feldhaus : The technology of prehistoric times, historical times and the primitive peoples. (Berlin 1914) 2nd edition (expanded to include later original contributions by the author). Munich 1965, pp. 1348-1351.
- Michael Allner: Tools . 2nd Edition. pietsch, Stuttgart 2020, ISBN 978-3-613-50881-1 , pliers, p. 24 .
ISO standards for pliers for trade and industry
- ISO 5745, Pliers and nippers - Pliers for gripping and manipulating - Dimensions and test values
- ISO 5746, Pliers and nippers - Engineer's and lineman's pliers - Dimensions and test values
- ISO 5747, Pliers and nippers - Lever assisted side cutting pliers, end and diagonal cutting nippers - Dimensions and test values
- ISO 5748, Pliers and nippers - End cutting nippers - Dimensions and test values
- ISO 5749, Pliers and nippers - Diagonal cutting nippers - Dimensions and test values
- ISO 6508-1, Metallic materials - Rockwell hardness test - Part 1: Test method (scales A, B, C, D, E, F, G, H, K, N, T)
- ISO 8976, Pliers and nippers - Multiple slip joint pliers - Dimensions and test values
- ISO 9242, Pliers and nippers - Construction worker's pincers - Dimensions and test values
- ISO 9243, Pliers and nippers - Carpenter's pincers - Dimensions and test values
- ISO 9343, Pliers and nippers - Slip joint pliers - Dimensions and test values
Web links
- Hand forging techn. Making flat-nose pliers ( Memento from July 28, 2013 in the Internet Archive )
Individual evidence
- ↑ General information about pliers on the homepage of the manufacturer Knipex
- ^ Franz Maria Feldhaus: The technology of prehistoric times, the historical time and the primitive peoples. 1965, p. 1348 f.
- ↑ Franz M. Feldhaus: The technology of antiquity and the Middle Ages. Potsdam 1931, p. 126.
- ↑ International Organization for Standardization (Ed.): ISO 5743 Pliers and nippers - General technical requirements . 3. Edition. ISO copyright office, 2004.
- ↑ Ralf Förster, Anna Förster: Introduction to manufacturing technology . Springer Vieweg, Berlin 2018, ISBN 978-3-662-54701-4 , 4.4.1 pliers.
- ↑ cf. exemplarily the coat of arms of Zangberg
- ↑ HAZET-WERK - Hermann Zerver GmbH & Co. KG. Retrieved November 17, 2018 .