suction cup
a) hemispheres filled with air
b) airless hemispheres
1. handle
2. airtight seal
3. Magdeburg hemisphere
4. air pressure
5. vacuum
A suction cup is a cup-shaped structure made of elastic material that is pressed against a smooth surface by a negative pressure . For this purpose, a cavity, enclosed by elastic material, is pressed in during attachment and the previously contained air is displaced. The pressure generated by the surrounding medium, usually air, exerts a force on the hollow body. This creates the impression that it is sucking on.
The principle of the suction cup is used by numerous aquatic animals in different shapes, for example in the form of sucking mouths, suction feet or suction tentacles like the octopus . In addition to the force effect due to negative pressure, adhesion through glandular secretions such as mucus in snails is often involved.
Even before these natural suction cups could be reproduced by human hands, which required skills in handling rubber or other suitable materials, animal suction cups were used. For example, ship owners were used to catch sea turtles. Fishing with octopuses is also known from the Mediterranean Sea . The Odyssey already describes the power of the suction cups of an octopus, on which the stones still hang when you pull it out of the sea.
Suction cups in technology
Artificial suction cups are primarily used to temporarily attach objects to smooth surfaces - such as kitchen appliances on work surfaces, navigation devices on windscreens or heating rods on aquarium panes. The suction force that can be achieved is proportional to the pressure difference and the effective area. A single suction cup can carry a heavy weight. Vacuum lifters are used in construction based on the same principle.
Suction cups in dentistry
At the beginning of the 20th century, when the functional impression to generate the suction effect and thus the hold of a full denture was not yet invented in dentistry , suction cups were built into upper jaw prostheses . However, over many years of use, these produced jaw defects and even perforations of the palate , whereupon this aid was abandoned.
Web links
Individual evidence
- ↑ Peter Toschkoff: Fastening of upper full dentures with special consideration of the suction devices: Inaugural dissertation . Ludwig Maximilians University, 1934 *.