Such mechanism requires no spring adjustment and has no backlash.

The upper end-piece (17) of the fuel assemblies does not comprise a bladed bearing support.

Since the stopper restricts the spring so as not to buckle the spring, a force efficiency of the spring increases.

It is thereby not necessary to replace the spring with a spring having a different tension.

During both the pumping and charging strokes of the piston, the piston return spring can assist the tappet return spring, but the tappet return spring does not assist the piston return spring.

Such mechanism requires no spring adjustment and has no backlash.

The compression coil spring (16) has a long pitch portion (18) at the center portion of the compression coil spring (16), and short pitch portions (17) at both ends of the compression coil spring (16).

A spring lock restrains movement of the spring shaft when a lift assist is not required, and releases the spring shaft when a lift assist is required.

The spring (38) is fixed against rotating.

The heel spring and toe spring comprise a foot spring.

The proposed spring device consists of a helically wound spring wire threaded onto the screw, which is unprotected and produces a limited spring force.

alarm mainspring with sliding attachment

The piston spring (15) has a spring constant which is higher than a spring constant of the element spring (20).

As analysed above, these conditions were not fulfilled.

Therefore a valve spring is not required.