Switchable rocker arm

A rocker arm for transmitting rotational motion from a camshaft to opening and closing motion of a combustion valve in an internal combustion engine, said rocker arm comprising:

• a body having a first wall and a second wall spaced laterally from said first wall such than a central opening is provided between said first wall and said second wall, said first wall having a first wall aperture extending therethrough along an axis and said second wall having a second wall aperture extending therethrough along said axis;
• an inner follower which selectively reciprocates along a reciprocation axis relative to said body, said inner follower being located within said central opening and being configured to follow a lobe of said camshaft, said inner follower having an inner follower first portion which extends through said first wall aperture and also having an inner follower second portion which extends through said second wall aperture;
• a lost motion spring which biases said inner follower to move relative to said body along said reciprocation axis in a first direction;
• and
• a lock member moveable along a lock member axis between 1) a coupled position in which said lock member engages said inner follower first portion and said inner follower second portion, thereby preventing said inner follower from moving relative to said body along said reciprocation axis past a predetermined position of said inner follower relative to said body in a second direction which is opposite of said first direction and 2) a decoupled position in which said lock member permits said inner follower to move relative to said body along said reciprocation axis past said predetermined position in said second direction.