Cannon crane
The cannon crane ( Swedish : Styckekranen ) in Stockholm on the east side ( Östra Brobänken (eastern bridge bank) ) of the island of Skeppsholmen is a wooden port crane from the 18th century. It is still functional today and is the only one of its kind that has been preserved.
As early as 1647 there was a pedal crane at this point for hoisting or lowering guns onto warships after the fleet had been transferred to the galley yard (Swedish: gälarvarv) on Skeppsholmen. This original crane was in operation for a hundred years until 1749 and had to be demolished due to significant defects. In 1751 it was replaced by today's cannon crane. An identical stepping crane had been in Skeppsgården (today Blasieholmen) since 1628 for arming the Vasa . The cannon crane consists of an eight-sided conical wooden structure without a brick base on wooden girders sunk deep into the ground with a completely rotatable eight-sided roof and boom, no rotatable roof top as with the pedal cranes in Germany. The entire crane building (height: 7.70 m to the edge of the roof) including the roof and boom are clad with sheet metal. The lifting force was provided by up to 20 crane runners in the two 4 m high treadmills. In addition to the weight of the load, the large number of winch drivers had something to do with the high accuracy of the cannon setting, whereby the load was lowered very slowly with pauses. Two hemp ropes run from the two rope drums sitting on the pedal wheel axle with a lateral flange over two sheaves in the boom end through a maiden known from sailing ship rigging instead of a hook, in whose keep (circumferential groove) the end rope for attaching the load runs. The rope ends run over two more pulleys back into the boom, where they are attached. This type of cable pick-up is very rare in pedal cranes, in which the (rounded) middle tread axle section usually also functions as a cable winch, here running through two steel support straps attached to the crane column. A slewing gear similar to a Dutch windmill was available for rotating the crane roof, as the Spreet beams with a central codend attached to both sides of the roof show (hence the rarer name Styckekvarnen - the cannon mill). Two doors on the sea and land side grant access.
In the course of its history, especially after the war port was relocated in the late 18th century, the crane was sometimes rented for a fee to private individuals, ship captains and trading houses, which helped the Swedish Navy to maintain its ships. In 1935, after 184 years of activity, the crane ceased operations and became a state-protected monument. In 1967 it received a new sheet metal cover and was temporarily rented to various organizations as a space. In 1978 a fire caused by carelessness damaged the crane. The Östermalm fire brigade tried to put out the fire, but the fire had destroyed significant parts of the crane such as one of the pedal bikes. However, it could be repaired again, the pedal bike was rebuilt according to the old specifications. Now the cannon crane was first marked as a monument, but fell into disrepair in the decades that followed. A commission was convened and money was raised so that a comprehensive repair could be carried out, during which both pedal bikes and other components were replaced. The cannon crane, which was 252 years old at the time, has been fully operational again in its old splendor since September 2003 and can be viewed. Two smaller guns in front of the crane indicate its former activity.
literature
- Hans-Liudger Dienel , Wolfgang Meighörner: The Tretradkran . In the series: History of Technology (publications by the Deutsches Museum ), Munich 1995 and 1997; ISBN 3-924183-33-3
- Katarina Juvander: Styckekranen på Skeppsholmen . Sverige Statens fastighetsverk, Stockholm 2005
- Michael Matheus : Medieval harbor cranes . In: Uta Lindgren (Ed.): European technology in the Middle Ages. 800-1400 , Berlin 2001 (4th edition, pp. 345-348); ISBN 3-7861-1748-9
- Andrea L. Matthies: Medieval Treadwheels. Artists' Views of Building Construction . In: Technology and Culture , Vol. 33, No. 3 Johns Hopkins University Press , Baltimore 1992 (pp. 510-547); ISSN 0040-165X
Web links
- History and description of the crane on Skeppsholmen (Swedish)
- Description with interior photos (swedish)
- History and description of the crane (Swedish)
- Illustrated brief description of various port cranes from the 14th to the 18th century (Swedish)
Coordinates: 59 ° 19 ′ 38.2 " N , 18 ° 5 ′ 4.5" E