Patent ID: 7934694
Filing Date: 2011-05-03
Classification: F15B,F16K

Abstract:
1. A single sided actuator comprising a cylinder, a pressure chamber defined by the cylinder, a spring return piston and an inner chamber area, in which a rack extends from an underside of said piston, in which said rack co-operates with a rotatable pinion mounted in said inner chamber area, and arranged normal to the rack, in which the pitch line of the rack is substantially aligned with the center of the piston, in which two or more return springs are arranged within said inner chamber area and are axially situated alongside the rack and the pinion, in which said return springs are arranged in equal groups of one or more on either side of the rack and pinion, such that the same spring pressure is provided on each side of the rack and pinion to ensure that a linear and balanced spring return force is always provided, and in which the rack and the pinion are shaped and dimensioned to provide sufficient space for said two groups of springs in the inner chamber area.