a valve structure in which a valve member moves into and out of contact with first and second valve seating areas , the valve member contacting the seating areas with different forces . the movable valve member is comprised of block members coupled together so that a change in their relative longitudinal positions produces a corresponding change in their relative transverse positions . a stem member moves the block members to spaced longitudinal positions and produces different longitudinal separating forces between the block member in these positions thereby to urge one of the block members in a transverse direction with different forces against the valve seating areas . the application of forces directly through block members and indirectly through springs is employed to provide different valve seating forces . block members for valve port blocking and valve port opening are utilized . a shock absorbing structure incorporating a movable spring holder is also utilized .