Patent GB-370480-A (GB)
Title: Improvements in starting and reversing gear for internal combustion engines
IPC: F01L13/00
Filed: 1931-01-01
Abstract: 370,480. Reversing; starting; stopping; regulating. BLACKSTONE, G. M., CARTER, F., and CARTER, E., Rutland Engineering Works, Stamford, Lincolnshire. Jan. 1, 1931, No. 36. [Classes 7 (v) and 7 (vi).] In a reversing gear comprising forward and reverse cams adapted alternatively to actuate the inlet and exhaust valves and the fuel-supply pumps, the movement of a control member first lifts the valve levers in their working planes, then displaces rollers axially on the ends of the levers, and finally lowers the levers so that the rollers fall on the alternative cams. The gear is also utilized during part of its range for controlling the power output in both forward and reverse directions. The invention is described as applied to a " spring injection " engine having 8 or 12 cylinders arranged in two banks each having a cam shaft 5 and a fulcrum shaft 9 provided with eccentrics on which the valve levers 3, 4 are pivoted. Each inlet valve 1 is actuated from the corresponding lever 3 through a rod 6 and lever 7, and the exhaust valves 2 are actuated directly from the levers 4. Fuel pumps such as are described in Specifications 228,261, [Class 7 (vi), Internalcombustion engines. Valves &c. for], 229,213, [Class 102 (i), Pumps &c.], and 229,966, [Class 7 (vi), Internal-combustion engines, Valves &c. for], are actuated by cams on the shafts 5 through levers 11. The fulcrum shafts 9 are turned for reversing and regulating by means of a hand-wheel 54 geared to a disc 55 provided with a pin 57 engaging a slot 58 in a rack bar 59, the disc 55 being also geared to an indicator needle 63. When the levers 3, 4 have been lifted from their cams, the cam followers are displaced axially, to bring them over the reverse cams, by forks 50 carried by sliding rods 51 connected by bell cranks 52 to a rod 53 carrying a roller 61 engaging a slot 60 in the rear face of the disc 55. The shafts 9 also carry cams 10 adapted to engage pins 10a on the fuel-pump levers 11 and to lift the rollers 12 from the corresponding cams on the shaft 5, so that the injector plungers (normally forced back by the pump to an extent permitting the reception of a predetermined quantity of fuel) are held down ; fuel is thus prevented from entering the injection chamber 13, and the fuel pumped in excess passes a relief valve. Compressed air for starting is supplied from a container through a conduit 20 and a valve 21 to a starting-air chamber 22, Figs. 2 and 4, on each cylinder, the chamber being provided with an inlet valve 23 and a valve 24 opening into the cylinder. During starting, the valve 23 is actuated by a cam 27 on the shaft 5 through a lever 26 on the fulcrum shaft 9 and a push rod 25, the valve 24 being opened by air pressure and closed by a spring 28. A bellcrank lever 29 between the rod 25 and the valve 24 is given sufficient lost motion to allow the rod to fall into the position shown in Fig, 4 during normal running, leaving the valve 23 open and lifting the roller of the lever 26 off its cam 27. When stopping, by turning the shaft 9 to render the valve levers 3, 4 inoperative, a cam 30 on the shaft 9 engages an additional lever 31 lying over the lever 26, so that the starting-air valve 24 is opened, allowing air to be drawn into and expelled from the cylinders to stop the engine quickly by wire-drawing the air current during and after the closing of the ordinary inlet and exhaust valves. The main starting-air valve 21 is opened by means of a pedal 35 connected to a bell crank 37 pivoted at 36 to a lever 32, which is connected to the valve 21 and carries a roller 33 engaging a cam 34 on the shaft 9. When the roller 33 is on a high part of the cam; depression of the' pedal 35 will open the valve 21, but when the shaft 9 is turned to the stopping position the roller '33 lies over a low part of the cam, from which it is lifted by a spring 40, so that depression of the pedal 35 only depresses the roller idly. In operation, with the needle 63 at the "full speed ahead " position a, Fig. 1, rotation of the hand-wheel 54 to move the needle from a to b turns the fulcrum shaft 9 to diminish slightly the period of opening of the inlet and exhaust valves, and the amount of fuel passing through the injection chamber diminishes to zero at position b; between a and b it is possible to open the main starting-air valve 21. From b to d the valve levers 3, 4 continue to be lifted until they are clear of the cams; and at c the valves 24 are opened by lever 31 to enable wire-drawing past the valves 2 to ensure stoppage. Between d and e the.lever rollers are moved from the forward to the astern cams, at f the valves 24 are' closed, at g the main starting- air valve 21 can be opened, and h is the "fullspeed astern" position.