Abstract: The invention provides a valve which comprises a body defining a passageway therethrough, a valve seat in the passage, a valve closure disposed in the passageway adjacent the valve seat, and an operating spindle projecting transversely into the passageway, the arrangement being one wherein movement of the spindle into the passageway causes the closure to be urged against the valve seat to close the valve, and movement of the spindle in a direction out of the passageway permits movement of the closure away from the seat to open the valve, the operating spindle being coupled to the closure by means of an intermediate articulated arm or roller.