Grease nipple

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A grease nipple on a plain bearing
A grease nipple on the driver's door of a VW Beetle convertible from 1956

A grease nipple or Grease nipple is a small piece, about a bearing by means of a grease gun with a lubricant can be supplied. This process is also known as smearing .

In some applications the term oiler is also used (e.g. for hub gears ). Helmet workers have a foldable cap to protect against the ingress of dust. In contrast to most grease nipples, the openings of lubricators are often not closed by a non- return device so that the oil can run freely through the bore.

Grease nipples are used in equipment, machine and vehicle construction. They are increasingly being displaced by central lubrication systems; in modern cars and motorcycles, they have lost their importance due to the introduction of low-maintenance rod ends with a lifelong grease filling. Grease nipples can still be found frequently in the construction machinery sector or on agricultural machinery .

functionality

Grease nipples are connected to the associated component by a thread. The nipple connection allows a positive fit of a grease gun. The bore or cavity of most grease nipples is now closed from the inside by a small ball which is pressed against the opening from below by a spring. The pressure built up by the grease gun moves the ball into the interior of the nozzle, allowing the grease to flow past the ball. The function therefore corresponds to that of a check valve . When the pressure drops, the ball returns to its original position, seals the opening bore against dirt and at the same time prevents grease from escaping from the nozzle.

Standardization in Germany

Logo of the German Institute for Standardization DIN 71412
Area lubrication
title Conical grease nipple
Latest edition 1987-11
ISO -
Logo of the German Institute for Standardization DIN 3404
Area lubrication
title Button head grease nipples
Latest edition 1988-01
ISO -
Logo of the German Institute for Standardization DIN 3402
Area lubrication
title Ball grease nipple
Latest edition 1969-03 (withdrawn from 1986-11 without replacement)
ISO -

Lubricating nipples are (, Form B Form C 45 ° 90 °) in a straight (Form A) or angled construction with different conical Einsetzgewinden in DIN standardized 71,412th Form D used to be a variant for motorcycles with an M6 thread shortened by 2 mm compared to form A. Conical grease nipples are suitable for hand-operated and machine-operated grease guns.

  • Designation example, conical grease nipple DIN 71412-A M8x1
This is a grease nipple in accordance with DIN 71412 of form A (straight) with a nominal thread diameter of 8 mm and a thread pitch of 1 mm; the thread is tapered.

Until September 1962, conical grease nipples were referred to by DIN as conical bead grease heads .

Button head grease nipples (formerly: flat grease heads) have fine threads for screwing in (form A), are intended for lubrication points with large volumes of lubricant and are standardized in DIN 3404, until August 1962 also as form B with drive-in pins. Because of the form-fitting connection, button head grease nipples are suitable for hand-operated and machine-operated grease guns.

  • Designation example button head grease nipple AM ​​16 × 1.5 DIN 3404
This grease nipple according to DIN 3404, form A (with threaded pin) has a cylindrical metric fine thread M 16 × 1.5.

Even funnel grease nipple to DIN 3405 have cylindrical fine thread . Because of the particularly flat nipple head, they are particularly suitable for flush and recessed installation. However, a non-positive connection of the lubrication device is necessary.

Ball lubrication nipples according to DIN 3402 are hardly relevant anymore, the last edition of the standard dates from March 1969 and was withdrawn in November 1986. They have a tapered thread, a lubricating head of normal length and require a non-positive connection of the lubricator nozzle when lubricating. Like funnel-type lubrication nipples, they have the advantage that lubrication from angular positions is possible without the use of an elastic link.

literature

  • Klaus Günter Krieg, Wedo Heller, Gunter Hunecke: Guide to DIN standards. Development - construction - production, BG Teubner Verlag, Stuttgart 1983, ISBN 978-3-519-06320-9 , p. 68.
  • Wilhelm Matek, Dieter Muhs, Herbert Wittel, Manfred Becker: Machine elements . Standardization - Calculation - Design, 13th edition, Friedrich Vieweg & Sohn Verlag, Braunschweig 1994, ISBN 978-3-322-94344-6 , pp. 481-483.
  • Wolf-Dieter Franke: Lubricants and their application. C. Hanser Verlag, Munich 1971, ISBN 978-3-4461-0027-5 , pp. 138-140, 161.
  • Georg Heinz Göttner: Introduction to lubrication technology. Volume 2, Basics - Interrelationships - Applications, K. Marklein Verlag, 1966, pp. 199-204.

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