The 20.1, 30.1 and 40.1 ELAs are now available in standard versions with incremental encoders, absolute encoders, protective bellows (flexible protection boot) or a “free shaft end.” Herewith, Pfaff-silberblau said it meets the increasing demand for special options and add-on parts for its linear actuators.

For position measurement or for electric synchronisation of several ELAs, the linear actuators can now be ordered with a factory installed incremental encoder (IE) or an absolute multiturn encoder (AME), which are mounted on the drive’s second shaft end.

Depending on the specific version, the IE supplies 10 or 20 impulses per revolution. Its standard voltage supply is 11 to 27 VDC, and the output level can be selected as 5 or 11-27 volts.

The AME offers a maximum overall resolution (encoder capacity) of 25 bits, and 256 steps per revolution are pre-programmed (max. of 13 bits). Up to 4,096 revolutions can be counted (maximum of 12 bits).

The supply voltage lies between 11 and 27 VDC. There are two options available for reading out acquired data. First, the absolute multiturn encoder with an RS 422/ SSI interface transmits a pre-set gray code (programmable output code). When data is transmitted via Profibus-DP at a transmission rate of 9.6 kBaud to 12 MBaud, the output code is parameterised according to PNO Class 2. The address can be set using a DIP switch. Other rotary transducer versions are also available upon request.

Additional new features for the ELAs from Pfaff-silberblau include the standard “free shaft end” for manual re-adjustment of the linear actuator using a handwheel, as well as precisely fitted bellows for deployment in harsh environments.

Said Pfaff-silberblau: “The latter feature protects the shaft housing and the sealing package against external influences such as dirt, shavings, or other deposits; and outdoors, it offers protection against rain, snow and ice.”

The bellows consist of a thermoplastic that is resistant to the influence of weather, ozone and light. Although as a standard, it is configured for the temperature range from -10°C to 60°C, it is also available upon request in special versions for extremer temperatures.

Pfaff-silberblau’s electromechanical linear actuators with the ELA 20.1/ 30.1 and 40.1 model sizes can be supplied for use in potentially explosive atmospheres containing dust and gas in accordance with EU Directive 94/9/EC.

Depending on the size and version, they have standard stroke lengths of 200 to 800mm and a maximum dynamic axial load of 1,300kg. Speeds can reach up to 84mm per second depending on the load and the ratio.

Added Pfaff-silberblau: “The self-locking trapezoidal screw and an optional brake ensure ideal safety, and the encapsulated construction and high-grade lubrication ensure a long service life.”

For longer duty cycles and more stringent requirements with regard to positioning accuracy, there is a variety of standardised ball screws available.

Pfaff-silberblau will be showing some of its ELA versions at the Motek 2006 in Sinsheim in Hall 4 at Booth 4327. Besides a series of electromechanical screw rams, an extensive range of worm-gear screw jacks and spectacular applications, other exhibits will include the PHOENIX Lifting column from Pfaff-silberblau’s subsidiary ALLTEC.