Patent GB-191214324-A (GB)
Title: Improved Mechanism for Driving Rotary Magnetos on Internal Combustion Engines to Facilitate Starting.
Inventor: LAWRENCE BENJAMIN
IPC: F02P15/12
Filed: 1912-06-19
Granted: 1913-06-19
Abstract: 14,324. Lawrence, B. June 19. [Cognate Application, 21,582/12.] Magnetos, driving.-Trip mechanism for ignition magnetos is constructed so that it.can be operated either by hand or from the driving- shaft at will. Fixed to the driving-shaft B, Fig. 1, by a sliding feather B<2> is a sleeve B' engaging a sleeve A', fast on the magneto shaft, by means of pins or rollers B' and slots having helical portions A<2> and straight portions A<3>. Journaled on an extension of the magneto is a cam ring D, Figs. 1 and 2, which may be rotated against the action of a spring by a cord D<2>, and is provided with two cam peaks having faces D<4>, D<5> shaped as shown. Bearing on the cam ring D is a sleeve E having cam blocks E<1> which normally rest on the slow-pitch parts D<6> of the cam faces D<4>. External and internal flanges B<4>, E<4> on the sleeves B<1>, E respectively are provided with lugs B<7>, E<5> which interengage when the blocks E<1> ride up the faces D<4>. Rotation of the ring D is limited to about 180 degrees by a stop D<8> co-operating with two shoulders D<15>. When the ring D is rotated by the cord D<2>, the sleeve E also rotates until stopped by a pin E<7> contacting with a spring blade D<9>, whereupon the blocks E<1> ride up the faces D<4>, thus bringing the flanges B<4>, E<4> and lugs B<7>, E<5> into contact and pushing the sleeve B<1> back against the action of a spring C. This brings the pins B<3> to the ends of the slots A<2>, as shown in Fig. 1, thus rotating the magneto shaft backwards. Further rotation of the ring D allows the blocks E<1> to ride down the cam faces D<5>, and the pins B<3> to be forced along the slots A<2> so as to rotate the magneto shaft forward sharply. Normal drive then ensues through the straight portions A<3> of the slots, the lugs B<7>, E<5> being kept apart by the end of the spring D<9> bearing on a flange E<6>. Longitudinal displacement of the sleeve E on return of the ring D to its normal position is prevented by engagement of the faces E<3> with the shoulders D<7>. If it be desired to start the engine by cranking, the ring D is first rotated to bring the lugs B<7>, E<5> into contact, after which the mechanism operates as before except that the ring D is stationary and the sleeve E is rotated. In order, in this case, to obtain repetitive action of the trip until full speed is attained, a finger D<10>, Fig. 3, may be arranged to be inserted, as shown, between the ring D and the sleeve E, and to be removed by a cam D<11> on the ring D. Alternatively, the lugs B<7>, E<5> may be held in contact by a lever device applied to the ring E. As speed rises they are prevented from engaging by centrifugal pawls F, the ends of which F<1> fall behind shoulders F<2>. Fig. 3 also shows a modified method of connecting the sleeve B<1> to the driving-shaft, in which a helical feather G' on the sleeve slides in a helical groove G<2> in the cover B<5>. A torsion spring G is placed between the cover B<5> and the sleeve B<1> so as to tend to unwind when the trip is made. Trip mechanism operated by the driving-shaft only is described in the Provisional Specification, and is shown in Fig. 1 thereof. Mounted on the magneto spindle A is a lever B, shaped to engage at its ends a pawl C, fixed on a pin E, adapted to be secured in any position in a slot in a bracket K. Blocks G, attached to a driving-disk I by pins H, are connected by springs F which bear on a flat-sided boss on the lever B. Retention of the lever B by the pawl C thus bends the springs F until the end of one of the pins H releases the lever by pushing the pawl aside. This impact is sufficient at high speeds to force the pawl to the dotted position, in which it is retained by a spring D.