 | This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Scharfenberg coupler" – news ·newspapers ·books ·scholar ·JSTOR(December 2014) (Learn how and when to remove this message) |
| Part of a series on |
| Rail transport |
|---|
 |
| Infrastructure |
| Rolling stock |
| Urban rail transit |
| Other topics |
 Transport portal |
TheScharfenberg coupler[1] (German:Scharfenbergkupplung, abbreviatedSchaku) is a commonly used type of fully automaticrailway coupling.
Designed in 1903 by Karl Scharfenberg inKönigsberg, Germany (todayKaliningrad, Russia), the coupler has gradually spread from transit trains to regular passenger service trains, although outside Europe its use is generally restricted to mass transit systems. TheSchaku is superior in many ways to theAAR (Janney/knuckle) coupler because it also automates electrical and pneumatic connections and disconnections. However, there is no standard for the placement of these electro-pneumatic connections. Some rail operators have placed them on the sides while others have placed them either below or above the mechanical portion of the coupler.[dubious –discuss]
Scharfenberg and the abbreviation Schaku are registered trademarks of Voith Patent GmbH.[2][3] For this reason, only couplings fromVoith can use this name. The associated coupling principle is also referred to as latch type design.[4] It is not protected by a patent and is used with fully compatible couplers from manufacturers such asDellner orWabtec.
The face of the Scharfenberg coupler has a protruding cone and a matching cup. Inside the cone there is a rigid metal hoop connected to a revolving, spring-loaded metal disk with a notch on the opposite side. When ready to couple, the spring turns the disk so the hoop is extended from the cone. As the cars meet, the hoop enters the cup on the other coupler, stopping against the disk. The hoops are then pressed back into their own coupler, causing the disks to rotate until the notches align with the hoops. After the hoops have entered, the notches on the disks spring back into the hoop extended position, locking the coupling. In the coupled position, forces on the hoops and disk will balance out, which means that the Scharfenberg, unlike many other couplers, is not dependent on heavy latches to stay locked.
Small air cylinders, acting on the rotating heads of the coupler, ensure the engagement of the components, making it unnecessary to use force to get a good coupling. Joining portions of a passenger train can be done at very low speed (less than 3 km/h or 2 mph in the final approach), so that the passengers are not jolted. One problem with the coupler is that it is often hard to connect it in a curve. Planned coupling is normally done on a straight flat track, while there has been trouble coupling a broken down train at an unplanned place.
Rail equipment manufacturers such asAlstom offer theSchaku as an option on their mass transit passenger cars and locomotives. Presently, Scharfenberg couplers are in use on the following passenger transit systems:
 |
.jpg)
Coupler heads for passenger trains that work according to the Scharfenberg principles:[10][11]
Couplers for freight trains based on the Scharfenberg principles:[12][13]
Media related toScharfenberg coupler at Wikimedia Commons