The device (30) comprises a displaceable inner piston (50) and an outer piston (54) which is displaceable in relation to the internal piston (50) surrounding said inner piston in a radial manner.

The biasing force is applied to the inner plunger (12) when the inner plunger (12) is engaged to the outer plunger (7).

The plunger barrel assembly comprises an inner and an outer plunger barrels.

The folded plunger assembly (200) is provided with an inner plunger barrel (102), an outer plunger barrel (104) and a plunger plug (106).

The rotation of the chassis (8) causes the inner plunger (12) to rotate relative to the outer plunger (7) and disengage the outer plunger (7) to remove the biasing force from the drive spring (6) on the inner plunger (12).

An actuator assembly includes an inner piston (36), an actuator housing (34), and an outer piston (32).

The system further has a piston lock assembly for selectively locking the first outer piston to the second inner piston.

Further push of the plunger barrel in forward direction, creates a vacuum between the plunger plug 110 and inner plunger barrel 108.

The inner plunger barrel housing inside the outer plunger barrel is also provided with a second piston seal 150 at proximal end.

The internal piston is hollow and includes a thin membrane front.

The inner piston may include a lower surface that directly, or through an intervening sliding pin, actuates an engine valve in response to the application of fluid pressure on the inner piston.

A carpule for a dental syringe provides an internal piston disposed between a front septum and a rear plunger.

The device uses a first cylinder having an external thread, and an internal piston.

The system has a plurality of linear actuators each having a first outer piston concentric with a second inner piston.

The inner, or signal, plunger (18) is maintained in coaxial relationship with the ground sleeve by means of a dielectric spacer member (108, 108', 108'') mounted on the inner plunger (18).