Patent GB-631698-A (GB)
Title: Improvements in reversing mechanisms for fuel-injection engines
IPC: F01L13/00
Filed: 1947-06-17
Abstract: 631,698. Starting ; regulating; valve gear. NORDBERG MANUFACTURING CO. June 17, 1947, No. 15945. Convention date, Aug. 1, 1940. [Classes 7 (v) and 7 (vi)] In a reversible internal combustion engine of the fuel-injection type, wherein the fuel-injecting means is operated by cams on a camshaft driven from the engine crankshaft and wherein a reversing mechanism is adapted, upon performing its full stroke between its forward and reverse positions, to adjust the phase relationship between the crankshaft and camshaft for the desired direction of operation of the engine and wherein a lead-adjusting device is adapted to vary the timing of the fuelinjecting means in each direction of operation of the engine, the drive train from the crankshaft to the camshaft includes a controlling member which, when rotated, changes the phase relationship between the shafts both for establishing forward and reverse running conditions and also for timing the fuel injection, a driving connection from the reversing mechanism to the controlling member is adapted upon full stroke of the reversing mechanism to rotate the controlling member sufficiently for engine reversal, and the driving connection includes a reversible-motion transmitting-mechanism which is adapted to be reversed by full stroke of the reversing mechanism and to be actuated by the lead-adjusting device and thereby to adjust a shiftable element which rotates the controlling member through a limited lead-adjusting range in one or the other direction depending upon the position of the reversible-motion transmitting-mechanism which in turn depends upon the position of the reversing mechanism. A pinion on a two-stroke engine crankshaft has half the pitch-circle diameter of a ring gear 32, Fig. 4, on a cage 33 journalled on the camshaft 17, which latter is displaced angularly to condition the engine for reverse operation. The camshaft 17 turns at crankshaft speed due to bevelled planet-wheels 35 meshing with a sun gear 36 fixed on .the controlling member 34 and a driving gear 37 fast on the camshaft 17, since the controlling member is stationary except during reversal of the engine. Cams 18 and the camshaft operate variable-feed " Bosch " type fuel-pumps. The camshaft 17 is angularly displaced by means of a rack 47, Fig. 2, which is actuated through the reversing mech anism 44, operated by compressed air or any other suitable means, that has an oil dashpot 42 connected to its piston rod 45. Air admitted to either conduit 53 or 54 depending upon the desired direction of engine rotation, acts on a stepped piston 56 and moves it outwardly until the piston ports 65, 66 do not register with their respective conduits 63, 64 but connect the latter with conduits 53, 54, respectively. Upon completion of the rack stroke the reversing mechanism 44 is vented and the piston 56 moved inwardly by its compressed spring so that a latch 58 locks the rack 47 by engaging in one of its recesses 59 or 61 to prevent the air being cut off until the reversing mechanism has completed its full stroke. The rack 47 has inclined teeth that mesh with the helical teeth of a gear 71, Fig. 4, splined onto the member 34, so that axial movement of the gear 71 across the rack face entails limited rotation of the member 34 and hence camshaft 17. The outer end of the member 34 is counter-bored to receive an axially-movable plunger 72, Fig. 8, whilst a cylindrical block 73 is swivelled in the plunger 72 and connected with the gear 71 by a flat cross-pin 76. Since the gear 71 rotates through 108 deg. a part of its teeth, at two diametrically opposite points, are dispensed with to enable the cross pin 76 to be secured to the gear 71. The member 34 is axially slotted to permit axial movement of the cross pin and associated parts and the plunger 72 is arcuately slotted 79 to allow angular movement of the cross pin 76. The outer end of the plunger 72 is bifurcated to provide two lugs 81 that are pinned to a pair of channeled links 83 in each of which slides a block 87, the two blocks being pivoted to a slider 89 travelling in a guide way 91 to move at right angles to the axis of the member 34. The slider 89 is connected by link 92 through a servo-motor (not shown) with a governor 93 which is shown in Fig. 4, with the slider 89 and associated parts in the low engine-speed position, these parts constituting the reversible-motion transmitting- mechanism. The other ends of links 83 are pinned to a yoke that is pivoted to a threaded member 95, Fig. 4, engaging a nut 97, the latter being journalled at 99 and provided with helical teeth 101 which mesh with gear 71 so that whilst the nut 97 is turned by angular movement of the gear 71 it is unaffected by its axial movement. Since the plunger 72 is connected through the link system with the governor, the angular position of the camshaft, and hence the timing of the fuel pumps varies in accordance with engine speed in either direction of engine rotation. Thus engine reversal is effected by two concurrent adjustments of the angular position of the camshaft relatively to the crankshaft, the basic adjustment establishing the conditions for reversal and the second being a variable adjustment brought about solely by axial displacement of the gear 71. Specification 630,460 is referred to.