Patent GB-190015109-A (GB)
Title: Improvements in Automatic Valve Gearing and appliances therewith for Steam Engines and other Fluid Motive Power Engines
Inventor: LAMBERT GEORGE LEWIS
Filed: 1900-08-24
Granted: 1901-08-24
Abstract: 15,109. Lambert, G. L. Aug. 24. Valve gear; stop gear.-Relates to automatic expansion valve gearing of the disengaging or releasing type, suitable for engines with separate admission and exhaust valves at each end of the cylinder, in which the disengagement is effected by vertically-sliding tappet rods, and comprises improvements on the inventions described in Specifications No. 4340, A.D. 1877, No. 3193, A.D. 1881, and No. 10,871, A.D. 1886. Fig. 1 shows a front elevation, and Fig. 2 a side elevation of the gear. The spindles of the two exhaust valves and of the two admission valves are reciprocated vertically by four cams on the shaft 36 ; those of the admission valves being furnished with disengaging- mechanism situated between the dash-pot and closing cylinders 61, 65, by which the connection between the valve spindles 6, 6 and the rods 58 can be broken and the valves allowed to close. The disengagement is effected by tappets 3 mounted on vertically-sliding tappet rods 1, 1 with inclined faces capable of acting on rollers 57 carried by levers by the movement of which the disconnection is brought about. The lower ends of the rods 1 pass through tubular rods 21 expanded at the middle to form open straps or rings 22 and capable of sliding in suitable brackets 29, 30. Pivoted to each ring 22 is a lever 19 linked to an arm 28 on the weigh shaft and connected each with one of the rods 1 by collars 16. The weigh shaft is adjusted by the engine governor. Each ring 22 is also connected by a pin 32 and sliding block with a lever 38 mounted on a shaft 41, and the two levers 38 are rocked separately by means of the cams 33, 34 on the main cam shaft 36. By these means the tappet rods 1 are reciprocated vertically, while at the same time they receive the additional adjustment requisite to vary the point of cut-off in accordance with the action of the governor. In order to allow the grade of expansion to be regulated independently by hand, the rods 1, 1 are screwed into the tappets 3, and provision is made for simultaneously rotating them by a hand-wheel 14 through toothed pinions. In this way the position of the tappets on the rods can be adjusted as desired. The details of the disengaging-gear between the rods 6 and 58 are shown in vertical section in Fig. 4, and in sectional plan in Fig. 5. The cylinder 61 is connected to the piston in the cylinder 65 by rods 63, and the cylinders 65, to which the valve rod 6 is attached, is connected to the piston in the cylinder 61 by a rigid connecting-piece 59. In the connecting-piece 59 slides a block 51 to which the rod 58 is jointed. By means of sliding detents 48 the block 51 can be looked to the piece 59 or released therefrom, the actuation of the detents being effected by arms on the shaft 50. On the shafts 50 are mounted the levers, which, as stated above, are acted on by the tappets 3. Means are also described for disconnecting the governor from the weigh shaft 28 and for locking the shaft 28 and so causing the admission valves to close permanently if an excessive speed is reached. This gear is shown in Figs. 10 and 11. The shaft 28 is actuated by the governor by means of a lever 75 loose thereon, but capable of being secured to it by a latch 73. The latch is operated by a short arm 74 worked by a lever 67 having a roller running in a camlike slot in a fixed disc 81. On the occurrence of an excessive movement, the lever 67 acts on the latch so as to release the lever 75 from the shaft 28, and at the same time the shaft 28 is locked by a notch in the disc 81 engaging with a pawl 80.