Lifter
The hoist is a historical tool for gradually lifting or lowering very heavy loads using muscle power alone.
Structure and mode of operation
A lifting drawer consists of a long lever whose axis of rotation is gradually increased to lift the load. This is done by alternately placing two iron bolts in two rows of holes in the opposite planks of a wooden frame.
To lift the load, the lever arm is moved up and down in individual steps and the bolt relieved of the load is raised by one position in the row of holes. Overall, the load can therefore be raised a maximum of the length of a vertical lifting drawer.
The raised load is lowered in the same way as it is lifted, only the bolts are moved down one position in the row of holes.
The lifting load is a collapsible and easily transportable hoist . Due to its small footprint, it was secured against slipping under load with wooden or iron struts .
History and title
One of the earliest illustrations and descriptions of a hoist can be found in the book "Recueil de machines" from 1617 by Franyois Thybourel and Jean Appler.
In 1723 Jacob Leupold mentions the German lever door in his book "Theatrum machinanrum", which was already described in 1651 by Daniel Schwenter.
Christopher Polhem invented the Swedish lever hoist in 1740.
Lifting shutters were further developed and protected with numerous patents until the 19th century, such as B. Friedländer and Josephson's hoist in Berlin 'For the gradual lifting of heavy loads' with DRP class 35 no.31798 from January 18, 1885. When building the Wittenberg Elbe bridge, the Berlin company Belter & Schneevogel used 32 hoists each with 2, 5 t load capacity for lifting the beams, each weighing 80 t. The simultaneous movement of all levers took place on command, which in this case was even carried out by soldiers.
Lifting shutters allow the load to drop back a little between two lifts, by which it must then be lifted again. Therefore, they were later displaced by winches and then completely lost their importance with the increasing motorization of forestry in the 20th century.
On September 30, 1953, the municipality of Anspach was officially awarded a coat of arms, which shows two bells and a lever door.
In some areas of Germany the lifting drawer is called a lifting drawer or a rocking box. In the 4th part of the Krünitz Encyclopedia , the lever drawer is also known as a tree hoist or wood lifter . In Frisian, the lifter is called Heewe for short . If the lever is at an angle, it is also called a lifting jack .
Special forms
A distinction is made between the German, French and Swedish lever handles. The latter was also used to raise marksmen . In the French lever drawer, the variable axes of rotation are formed by the incisions of a saw-like toothed rod on two opposite sides and standing vertically.
From this the stick winch is developed and later also the rack and pinion winch .
literature
- Johann Friedrich Lempe: The concept of machine theory with regard to mining , Volume 1, Verlag Siegfried Lebrecht Crusius, Leipzig 1795
- B. Harres: The School of Architecture , Volume Two, First Section, The Carpenter's School, Otto Spamer Publishing House, Leipzig 1863
- Friedrich Meinert: Textbook of Mathematics , Part 3, Mechanical Sciences, Halle 1795
Web links
- The loading of tree trunks with the hoist as an educational film by the IWF Göttingen from 1971, author: Arnold Lühning.
- A felled oak is loaded with a hoist in an educational film from the IWF Göttingen from 1980, author: Arnold Lühning.
- Lifting door of the Westerwald Landscape Museum, Hachenburg
- Description and pictures of the Anspacher Heblade
Individual evidence
- ↑ Herders Conversations-Lexikon , Freiburg im Breisgau 1855, Volume 3, p. 246.
- ^ Meyers Großes Konversations-Lexikon , Volume 9, Leipzig 1907, p. 25.
- ↑ Handbook on the History of Natural Sciences and Technology, Prof. Dr. Ludwig Darmstaedter, Springer Verlag, 1908, page 112.
- ↑ Handbook on the History of Natural Sciences and Technology, Prof. Dr. Ludwig Darmstaedter, Springer Verlag, 1908, page 171.
- ↑ Handbook on the History of Natural Sciences and Technology, Prof. Dr. Ludwig Darmstaedter, Springer Verlag, 1908, page 183.
- ↑ Prof. Ad. Ernst: The hoists. Theory and Critique of Executed Constructions , Volume 1, Springer Verlag, 1903, pp. 86–87.
- ↑ Approval for the use of a coat of arms for the municipality of Anspach in the district of Usingen, administrative district of Wiesbaden from September 30, 1953 . In: The Hessian Minister of the Interior (ed.): State Gazette for the State of Hesse. 1953 No. 42 , p. 912 , item 1182 ( online at the information system of the Hessian state parliament [PDF; 4.0 MB ]).
- ↑ Johann Friedrich Lempe: The concept of machine theory with regard to mining , Volume 1, Verlag Siegfried Lebrecht Crusius, Leipzig 1795, p. 107.
- ^ Heinrich August Pierer: Encyclopedic Dictionary of Sciences, Arts and Crafts , Volume 9, Hahn Altenburg, 1828, page 220 .