GB1039803A - Rocker arm for an internal combustion engine - Google Patents

Abstract

1,039,803. I.C. engine valve gear. FORD MOTOR CO. Ltd. Jan. 11, 1965 [Jan. 17, 1964], No. 2141/64. Heading F1B. An internal combustion engine rocker arm has two independent members 7, 9 independently pivotable by appertured forked ends on rocker shaft 5, a rotatable sleeve 15 being embraced by the forked ends. A clutch spring 31 e.g. of round wire or flat strip, encircles sleeve 15 and has tapered ends 35 and 33 respectively engaged by tapered portion 29 and the tapered portion 23 of a screw-threaded adjusting insert 19. When the valve is closed the ends of spring 31 force the members 7, 9 downwardly into contact with push rod 17 and valve stem 27. The initial valve opening movement applies tension to the end of spring 31 to lock the spring coil on to sleeve 15 which when rotated applies tension to the other end of the coil spring to move the valve stem 27 downwardly. In modifications stops are fitted to members 7, 9 to act in the event of clutch spring failure sleeve 15 either extends through forked ends 11, 13, Fig. 1 (not shown) or is replaced by an inwardly extending boss on one of the members and a clip holds member 9 and valve stem 27 together. In another embodiment Figs. 4, 5 (not shown) each rocker arm is of plastics moulded around a sleeve 39 and a spring 31. A metal insert 49, provides for the screw-threaded adjustment and a metal insert 41 forms the valve stem bearing surface. In another embodiment both free ends of a spring 58, Fig. 6 (not shown) are fixed to a common plate 63 which is bolted to a metal insert 65 in one arm of the rocker and a bight 60 of the spring engages a metal plate 67 on the other arm. The lengths of spring between the ends and the bight each encircle the sleeve 55. In another embodiment a plastics rocker arm moulded to a sleeve 75, Fig. 8 (not shown) is engaged by a saddle 79 mounted on a central post 73 which passes through the sleeve 75 with sufficient clearance to allow pivotal movement of the rocker arm. A nut 81 mounted on post 73 provides for adjustment of valve train clearance.