Ball coupling with roll damping
The ball coupling with roll damping , official: ball coupling with stabilizing device for center, is at the tiller mounted by supporters and works as a stabilizer together with the towing vehicle- trailer coupling . Such devices can also be retrofitted to existing drawbars.
purpose
The purpose is to reduce the yaw rate around the vertical axis of the trailer (rolling) and to increase its natural resonance frequency through damping . Together with other measures, higher train speeds can be achieved.
The yaw moment of inertia describes the moment of inertia around the vertical axis. To avoid lurching, it should be as small as possible. A high yaw moment of inertia arises when the trailer has large masses mainly in the front or rear. In return, a low yaw moment of inertia occurs when the largest masses are on the axle.
Customary versions
In the past, several versions were common, such as the Orismat 2000 or the Westfalia SSK, which works similarly to today's versions . Two versions of the ball coupling with roll damping are currently on the market:
- At the manufacturer AL-KO , the friction linings attack the clutch ball laterally (across the direction of travel),
- at the manufacturer Winterhoff, they attack the ball from the front and back (along the direction of travel).
construction
In all versions, damping is achieved through friction .
Separate friction strips
One of the first versions (Orismat) from 1977 made use of separate attachments that had to be mounted on both the shaft of the trailer coupling and the drawbar hitch. On both sides of the horizontal axis there were friction or sliding strips articulated to the shaft holder, onto which friction linings connected to the holder to the drawbar hitch were clamped. The contact pressure was set according to the instructions.
Friction shoes acting on the coupling ball
The Westfalia SSK was one of the first designs in which spring-loaded braking elements acted directly on the coupling ball. The contact pressure is selected to build up to 350 Nm of damping torque . The ball head must not be lubricated so that this torque can be achieved . Any protective coatings on brand-new ball heads or dirt and corrosion must also be completely removed. Insufficiently cleaned surfaces of the ball and friction linings are expressed by creaking noises during driving. Current versions have at least two exchangeable friction linings in the coupling's hitch.
Mode of action
After coupling, springs are internally preloaded by a lever; this spring force acts on the ball head of the towing vehicle via the friction linings. The spring travel is dimensioned in such a way that the pressing force is sufficient up to the wear limit. The user can usually recognize the progress of wear by means of limit markings that are permanently attached to the coupling.
Regulations
From a permissible total trailer weight of 1.0 to 1.2 × the empty weight of the towing vehicle, a "ball coupling with stabilization device for center-axle trailers" in accordance with ISO 11555-1 in the version dated July 1, 2003 is required for 100 km / h approval if neither the trailer nor the towing vehicle have recognized technical equipment for trailer stabilization.
Web links
Individual evidence
- ↑ a b 9th Exemption Ordinance to the StVO of October 15, 1998, accessed on March 31, 2014
- ↑ kuhnert-anhaenger.de , accessed on March 31, 2014