The handset activates electromechanical relays which, in turn, switch the drive currents. There are almost no restrictions as regards the selection of handsets and operating equipment.
(control without relay)
With this control concept, the drive currents are switched directly via the handset. Here, so-called X or Y cables are often used. With certain drive types, this functionality can also be integrated directly into the drive casing.
Mechanical retracting function:
Mechanical disconnection – because of the mechanical design, this function should only be activated in an emergency. Regular use might have a negative effect on the drive function.
The drive gear can be disconnected from the drive mechanism via a mechanical clutch element. This allows the corresponding furniture parts to be adjusted manually. Operation of the disconnection process is via a lever which is integrated in the drive casing; the lever can be activated remotely via cable controls or Bowden cables.
The clutch of the lowering function must be open during the entire downward movement.
Electrical retracting function:
This permits the emergency operation of a drive system in the event of a power failure. Depending on the type, the drive is supplied with power from either one or two 9-volt batteries.
As a result of the extremely reduced capacity of the sources of power, the drive movement is restricted to a single emergency operation. In particular, please note that in many cases it is not possible to carry out a drive movement under load.
The drive carries out a rotary movement. The double drive has a function between that of the rotation actuator and that of the linear actuator. Here, an internal straight movement is first converted into a rotary movement via an external fitting system. This is why the double drive is normally considered to be a linear actuator.