Safety-Couplings | GERWAH Backlash-free safety couplings


	GERWAH^® Safety - Couplings Product information

GERWAH backlash-free safety couplings work as spring- loaded positive couplings.
The special roller or ball guides guarantee a totally backlash-free transmission of the torque in both directions of rotation. (Patented)

The couplings are therefore especially suitable for use in speed and direction controlled drives.
Uniform loading of the rollers and balls guarantees high system stiffness, which is important especially for modern servo drives.
The roller and ball guides simultaneously guarantee high reliability and switching frequencies when used withhigh dynamic servo drives.

In the event of an overload the rollers or balls move out the guides (Figure 2 and 3). This results in an axial movement (S) which activates a proximity switch or limit switch that immediatly makes contact to switch off the drive.
To avoid damage to the safety coupling, the drive must be switched off immediatly after an overload.
The drive is shut down in order to allow the safety coupling to re-engage. The motor is then run at a very low speed or turned by hand. The coupling re-engages by itself, without any outside intervention, in the original angular position (C=synchronous engagement option) or in the next position (D=continuous engagement option).
After the re-engagement, which is clearly audible and displayed through the limit switch, the safety coupling again features the original disengaging torque moment.
After eliminating the cause of the overload the drive can be turned on again.


	GERWAH backlash-free safety couplings were developed for especially dynamic drives.




	Advantage of the system GERWAH^®

	The safety couplings work exclusively with specially selected disk spring with pronunced degressive characteristic. (See Figure 1 and 4) This advantage guarantees shortest switching times and a low residual torque. The couplinmgt disengages immediatly when the cut out torque is exceeded. The torque drops immediatly to a small residual value, typically 2 to 5%. The switching work required of our couplings corresponds to only a fraction of that of conventional safety couplings with progressive characteristic. (See Figure 1) This is a decisive advantage because even ultrashort suges in speed are rendered harmless by safety coupling.