An ortho-planar spring has a platform (14) movably coupled to a base (10) and being movable linearly with respect to the base along at least a portion of an axial direction (22) perpendicular to both a base surface and a platform surface. A resilient and flexible connecting structure (18) is connected to and between the base and platform. The connecting structure is bendable to develop (i) an axial force along the axial direction to bias the platform in a stable position with respect to the base, and (ii) non-axial forces which substantially sum to zero to preserve the orientation of the platform with respect to the base. Thus, the spring is very compact and does not have rotation between the deflecting ends. The spring may be associated with a valve opening (213), and a button (214) for restricting flow through the valve opening, to bias the button at a position with respect to the valve opening.