Thumbtack
From Wikipedia, the free encyclopedia
A thumbtack (known as a pushpin or a drawing-pin in the UK, India, Australia and New Zealand) is a short nail or pin with a large, slightly rounded head made of metal which is used to fasten documents to a background for public display and which can easily be inserted or removed by hand.
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[edit] Types of thumbtack
The most common thumbtacks are made by attaching a brass stem to a flat brass head. Some have coloured plastic tops, to make them more attractive.
Map pins, or push pins, are also a type of thumbtack. Map pins have a handle-like cover of plastic, which brings the pin out of the wall, allowing quick and easy removal from surfaces. Some other map pins have a round 1mm head to allow for easy removal. Both types come in a variety of colors. Map pins are safer than flat-headed thumbtacks when dropped on the ground or discarded on a surface, since they will not normally rest with the point upward.
[edit] History
The map pin was invented by Edwin Moore around 1900, the year in which he founded the Moore Push-Pin Company [1].
As far as is currently known, the thumbtack was invented by the clockmaker Johann Kirsten in the year 1903 in the town of Lychen in Uckermark, Germany [2]. He sold the rights to the invention to Otto Lindstedt, a businessman, who received a patent for the thumbtack on 8th January 1904. Lindstedt became a wealthy man while Kirsten, the clockmaker, remained in poverty.
Other sources ascribe the invention of the thumbtack to Austrian factory owner Heinrich Sachs in 1888 [3].
[edit] Physics
A thumbtack can be inserted by hand because of the large area of its head relative to the area of its point. When a relatively low pressure is applied across the large head of a thumbtack, a high pressure will be applied by the tip of the thumbtack. The low pressure on the head means the thumbtack will not pierce a person's finger. The high pressure at the tip allows it to pierce the surface to which the document is being fastened.
The thumb tack has a flat head in order to place the thumb, where as the drawing pin has a longer head which is gripped between two fingers to place.
[edit] Facts
- A thumbtack can be made to spin on its tip like a spinning top by holding the pin (with head facing up) between thumb and forefinger and rapidly spinning and releasing it in one fluid motion.
- Push pins can be loaded directly into the breech of a Tippmann 98 Custom paintball gun and fired as projectiles. A flying pushpin rapidly loses stability after a few feet due to poor aerodynamics.
- Thumbtacks are used as a weapon in professional wrestling.
