GN 491


  • Type R1: Right hand thread, shaft journal at one end
  • Type R2*: Right hand thread, shaft journal at boths ends
  • Type L1*: Left hand thread, shaft journal at one end
  • Type L2*: Left hand thread, shaft journal at both ends

* normally not available from stock

Guide tube DIN 2391

Steel chrome-plated SCR

End pieces / Slider


plastic coated

black, RAL 9005, textured finish

Fixing surface / mounting surface

machined, blank

Spindle with trapezoidal thread

  • Steel, blank
  • with ball-bearing
  • Positioning accuracy ±0.2 mm/300 mm travel

Follower nut, gun metal

Cylinder head screw DIN 912 /

Hexagon nuts DIN 985

Steel, zinc plated

In addition to the standard travel lengths specified in the above table for the double tube linear actuator GN 491 any length inside the maximum length is available.

In order to measure the movement and positioning of the sliders, digital position indicators can be added.

  • Installation kits GN 491.1  for position indicators

  • Mounting facilities of end pieces 
  • Technical information / Load data of Double tube linear actuators 

Mounting facilities of the end pieces

Horizontal with screws for thread d4 or bore d5



From outside, with screws for thread d3

From inside, with screws for bore d6

From inside, with screws for bore d5 / d7


Mounting facilities at the slider

Mounting with screws for thread d4 or bore d5


Assembly of position indicator and handwheel

Useage of installation kit, position indicator and handwheel, see table


dFx in NFy in N for length l =--Fz in N for length l =--MxMyMz
--5001000150050010001500in Nmin Nmin Nm

The specified forces Fy and Fz cause a flexure of the guide tube of approx. 0.5 mm.


The slider is moved via a bearing-type trapezoidal thread spindle and a aguide nut. The slider is guided through two parallel chrome-plated tubes, resulting in a high load capacity and allowing high bending moments to be compensated by the linear actuator.

For type GN 492, a second slider and an adapter plate extend the options for applications.

These double tube linear actuators have been designed for manual operation (handwheel). With the appropriate lubrication, they can also absorb rotary spindle speed of as much as 250 rpm.

The positioning accuarcy is 0.2 mm / 300 mm travel, the maximum revers play is 0.1 mm.

To measure the adjustment or the positioning, digital position indicators DD52R / DD51 may be attached.



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