GB474342A - Eccentric link motion for piston engines - Google Patents

Abstract

474,342. Engine valve-gear. MANSA, J. L. March 10, 1937, No. 7052. Convention date, March 10, 1936. [Class 122 (ii)] In a single-eccentric valve-gear, the free end 5 of the eccentric-rod 4 is constrained to move in a flat circular arc whose centre is adjustable so that the direction of its radii is not substantially altered. The non-adjustable point 11 on the rocking-beam 6 to which the rod is secured is pivotally connected to the valve. The beam 6 is fulcrumed adjustably at 7 to a lever 8. Small adjustments of the lever effect the cut off ; moving the lever 8 to the point 10 reverses the engine. The point 11 may be arranged on the other side of the lever 8 on an extension of the beam 6. The distance 7-5 relative to the crank throw is such that the point 5 traverses substantially a flat circular path. The valve reaches its top position when the eccentric has rotated through an angle v. Constructions are described which permit continuous variations of the-admission from the maximum cut-off in one direction to the maximum in the reverse direction without the mid-position of the slide valve being substantially altered. In the construction shown in Fig. 2, the valve-rod 21 extends below the beam 6 and the link 12 is directed downwards. The distances between the points 11-20, 5-3, and 7-9, are equal to one another. The arms 7-5 and 5-11 are so designed that the lever 8, rod 9, and link 12 are parallel. In a modification,. the point 7 slides in a curved slot designed, to prevent the mean position of the valve altering with variation of cut-off. In a further modification, the lever 8 is arranged above the beam 6 and the point 11 is arranged between the points 7, 5. The eccentric may be displaced, e.g. 180‹ relative to the crank.