Patent GB-655232-A (GB)
Title: Improvements in or relating to starting devices for internal combustion engines
IPC: F02N3/02
Filed: 1948-10-25
Abstract: 655,232. Turning-gear. PALFI, J. Oct. 25, 1948, No. 27760. [Class 7(v)] In a starting device of the kind in which a drum 15, Fig. 2, with a cord 23 wound thereon and provided at its free end with a, hand grip, is mounted coaxially with the engine shaft 4 and in driving connection therewith when the drum is rotated and comprising axially engageable and disengageable clutch parts 11 and 10 on the drum and the engine shaft, respectively, there is provided means for feeding the drum clutch part 11 towards the clutch part 10 when the drum is rotated in the starting direction and for retracting the drum clutch part 11 when the latter is rotated in the opposite direction, consisting of interengageable cam elements, such as part 25 and threaded spindle 33, carried by the drum and the starter housing 1, respectively. The starter housing 1 has adjustable feet 2 so that it may be supported by the engine 3 and aligned with the shaft 4, the latter having a pulley 5 for emergency pull-cord operation, which pulley has the clutch part 10 attached thereto. Within the housing 1 is the clutch part 11 slidably mounted in sleeves 12 held in the boss of the druw 15, which latter comprises a casing accommodating a clock-type return spring 16, the inner end of the spring being anchored to the casing 15 whilst the outer end is anchored to a stationary ring 17 secured to the housing 1. A pulley 22 secured to the drum 15 has wrapped around it the starting cord 23. Within a bore in the boss slides the nut 25 that is joined to the clutch part 11 by transverse pins 28, whilst through the nut 25 passes the spindle 33, the lower part of which carries a cross pin 43. To start the engine the cord 23 is pulled so that drum 15 and nut 25 rotate, the spindle 33 is prevented from rotating by a square part 37 engaging a corresponding hole in a friction disc 38, the latter being pressed against the housing 1 by a spring 40, and since the spindle is urged outwardly by a spring 41, the pin 43 enters the nut 25 and the spindle moves outwardly until the inner end of portion 37 abuts disc 38. Further travel of the spindle is opposed by spring 40 and, due to reaction, the nut 25 begins to move inwardly carrying the clutch part 11 into engagement with clutch part 10, further travel of the nut is prevented so that the spring 40 is overcome and the disc 38 is moved away from the housing 1 whereupon the spindle 33 and disc 38 rotate with the casing 15. The disc 38 does not therefore oppose the pull of the cord 23. A spring stop in the nut 25 prevents the clutch part 11 being advanced too far prior to engaging clutch part 10. When the engine fires the clutch part 11 is cammed outwardly carrying with it the nut and spindle assembly whereupon the cord 23 is released and the spring 16 rotates the casing 15 backwards to return the parts to their initial positions. Should the engine backfire a reverse rotation is imparted to nut 25 which releases the thrust on spindle 33 against disc 38 so enabling it to frictionally grip the housing 1 to lock the spindle; the nut 25 will then thread along the spindle and withdraw the clutch part 11. In a modification, the clutch part 10, Fig. 9, is formed on a flange 4a of shaft 4, the latter being extended to form a bearing 4b for the pulley 22 provided with clutch part 11 on which pulley the starting cord 23 is wound; the bearing permitting axial as well as rotational movement of the pulley to facilitate meshing of the clutch parts 10 and 11. The pulley is formed with a boss 22b around which is coiled the return spring 16 having its outer end anchored to a cup 115 fixed to the housing 1, the spring also serving to axially bias the rotating parts to separate the clutch parts 10 and 11. The boss 22b houses the spindle 33 that is formed at its inner end with two quick-pitch cam grooves 126 arranged to be engaged by cross pins 143 in the boss 22b to provide for the meshing of the clutch parts 10 and 11 and subsequent cranking of the engine. The outer end of spindle 33 is contoured and coacts with a friction disc as in Fig. 2. In a further modification the driven clutch part is formed on a spring-loaded sleeve that is keyed to the engine shaft whilst the cross pins are constantly in engagement with the cam grooves and the friction disc operates with both its surfaces. A multi-plate clutch may be used to replace the single friction disc.