Patent GB-567479-A (GB)
Title: Improvements in or relating to engine starting device
IPC: B64D47/00
Filed: 1943-09-28
Abstract: 567,479. Turning-gear. COMMUNICATIONS PATENTS, Ltd. Sept. 28, 1943, No. 15929. Convention date, Nov. 18, 1942. [Class 7 (v)] An engine-starting mechanism comprises two driving-members forming the armature and field respectively of an electric motor and arranged so that the first driving member is connected through step-up gearing to a flywheel, while the second is restrained from movement and then this first member is disconnected from the fly-wheel and is held stationary while the second driving member assists the fly-wheel in rotating the starting jaw. The housing for the starter consists of three sections 1 ... 3, the housings 1 and 2 being connected. by bolts 6 and housings 2 and 3 by bolts 7. The housing 3 has a flange 8 bolted to the engine crank-case 57. The starting motor 9 comprises an armature 10 and a field system 13 secured to a yoke 14 mounted in bearings 15, 16. The armature and the field are both restrained by ratchet or free-wheel devices against clockwise rotation (viewed from the left of Fig. 1). The arrangement is such that when connected for forward running, the armature rotates anti-clockwise while the ratchet mechanism prevents reaction rotation of the field yoke, while on "reversal," the armature is prevented from clockwise rotation and the field yoke rotates by reaction, also anti-clockwise. A series-wound motor is employed and " reversal " is effected by transposing armature brush connections. The yoke 14 carries a spider 22 serving as a carrier for planetary bevel gears 23 engaging a bevel ring on a fly-wheel 25 and a bevel gear 24 rotatable in one direction only and held stationary during fly-wheel acceleration. With the ratios shown, when the field is rotated, the fly-wheel is accelerated to twice the speed of the yoke 14. When the fly-wheel attains its full speed, the motor is " reversed." This causes rotation of the armature 10 and, by reaction, stopping of the yoke 14 and the planet carrier. The continued rotation of the fly-wheel will then be transmitted in reverse direction to the bevel gear 24 and thence to a uni-directional sun pinion 29 engaging planet gears 30 on a plate 39. The gears 30 coact with a stationary ring gear and the plate 39 serves through further reduction gearing described below to transmit the fly-wheel energy to the starter jaw 34. The rotation of the armature 10 transmits further power which is added to the fly-wheel energy. For this purpose the armature carries a pinion 37 connected through reversing idler pinions 38 to the gears 30 of the planetary system, Fig. 3. For a second stage of reduction, the pinion gear plate 39 has a hub formed as a sun-wheel 40 engaging planet pinions 41 engaging a second fixecl gear ring 45 and mounted on a pinion gear plate 43 formed with a sun pinion 54 engaging the planet pinions 46 of the final reducing train. These planets engage an internal gear 48 connected to the housing 2 through a multi-plate overload clutch 49. The pinions 46 of the final stage are carried by a plate 47 forming a flange on the hub of the jaw-advancing mechanism, the rotation of which advances the jaw 34 into engagement with the engine jaw 33. Thus, as soon as the motor is " reversed," the fly-wheel energy is added to the energy derived from the armature rotation to crank the engine.