Europaisches Patentamt 19 European Patent Office Office europeen des brevets © Publication number : 0 623 743 A1 EUROPEAN PATENT APPLICATION © Application number : 94303283.! © int. ci.5 : F02N 5/02, F02N 3/02 (22) Date of filing : 06.05.94 © Priority : 07.05.93 JP 131421/93 @ Inventor : Ohnishi, Hisao 29.10.93 JP 294542/93 1-16, Aoba-cho, Mizushima 24.02.94 JP 52883/94 Kurashiki-shi, Okayama (JP) @ Date of publication of application : @ Representative : Irons, Mark David et al 09.11.94 Bulletin 94/45 Page White & Farrer, 54 Doughty Street _ London WC1N 2LS (GB) (84) Designated Contracting States : DE FR GB IT © Applicant : NIKKARI CO., LTD. 482-1, Otami Okayama-shi, Okayama (JP) © Power storage type recoil starter. © A power storage type recoil starter used for, for example, an engine of a lawn mower includ- ing spiral springs that are wound when a starter 56 55 rope of a recoil pulley is pulled to rotate the starter wheel of the engine. The spiral spring is coiled up by a repeated pulling action of the starter rope and then suddenly recoiled by re- leasing a locking mechanism, thus rotating the main shaft of the engine powerfully to start the engine. CO co CM CO LU Jouve, 18, rue Saint-Denis, 75001 PARIS 1 EP 0 623 743 A1 2 BACKGROUND OF THE INVENTION holders by the rotation of the second drum in a direc- tion opposite to the starting direction so that the re- 1. Field of the Invention winding force of the spring is stored in the second drum as a rotational force in the starting direction, a The present invention relates to a power storage 5 locking mechanism which restrains the rotation of the type recoil starter for facilitating the start of internal second drum in the starting direction, and a release combustion engines. mechanism which releases the locking mechanism and disengages the clutch mechanism simultaneous- 2. Prior Art ly- 10 The object of the present invention is accomplish- Small internal combustion engines are equipped ed by another unique structure for a recoil starter with a recoil starter, and the starting of the engine is structure wherein a starter wheel which is attached to accomplished by pulling a starter rope that is recoiled. the main shaft of an engine and a recoil pulley which In such recoil starters, a certain amount of exper- rotates the starter wheel in the starting direction are ience is necessary to start the engine. The trick is to 15 installed separately, and between these two ele- pull the starter rope strongly at the time the air in the ments are provided: a first drum which is rotated by cylinder of the engine is compressed immediately pri- the recoil pulley in the opposite direction from the or to the firing of the plug. However, this operation is starting direction, a rotatable second drum, a speed not skillfully performed by inexperienced persons reduction mechanism which is installed between the and people who have limited strength. These people 20 recoil pulley and the first drum, a one-way clutch tend to pull the starter rope with an uneven strength mechanism which allows the rotation of the first drum and at a relatively slow speed. The result is that the in the starting direction and restrains the rotation of spark of the plug is small, and ignition does not easily the first drum in the direction opposite to the starting occur. Especially in recent engines equipped with direction, a flat spiral spring which is installed be- electronic ignition devices, the spark is small, and 25 tween the first and second drums so as to be wound starting is not easy. by the rotation of the first drum in the starting direc- The problem can be solved by an engine equip- tion so that the rewinding force of the spring is stored ped with a starter motor. However, this motor is ex- in the second drum as a rotational force in the starting pensive and increases the weight of the engine. Es- direction, a locking mechanism which restrains the ro- pecially for garden equipment which is carried and op- 30 tation of the second drum in the starting direction, and erated with the engine mounted thereon, such a a release mechanism which releases the locking weight increase is not welcome. In addition, there are mechanism. also problems in terms of power consumption. The object of the present invention is accomplish- ed by still another structure for a recoil starterwhere- SUMMARY OF THE INVENTION 35 in a starter wheel which is attached to the main shaft of an engine and a recoil pulley which rotates the star- Accordingly, it is a primary object of the present ter wheel in the starting direction are installed sepa- invention to solve the problems described above. rately, and between these two elements are provided More specifically, in the present invention, power is with: a first drum which is rotated by the recoil pulley stored in a recoil starter via flat spiral springs, and at 40 in the opposite direction from the starting direction, a the time of starting, the stored power is released all rotatable second drum, a speed reduction mecha- at once so that the starter is rotated at a high speed nism which is installed between the recoil pulley and to start the engine. the first drum, a one-way clutch mechanism which al- In order to accomplish the object, the recoil star- lows the rotation of the first drum in the starting direc- ter of the present invention uses a unique structure ts tion and restrains the rotation of the first drum in the wherein a starter wheel which is attached to the main direction opposite to the starting direction, and a flat shaft of an engine and a recoil pulley which rotates spiral spring which is installed between the first and the starter wheel in a starting direction are installed second drums so as to be wound by the rotation of the separately, and between these two elements is pro- first drum in the starting direction so that the rewind- vided: a first drum which is rotated by the recoil pulley so ing force of the spring is stored in the second drum as in the direction opposite from the starting direction, a a rotational force in the starting direction. second drum which is coupled to the first drum so as With any one of the above structures of the pres- to be rotated, a speed reduction mechanism which is ent invention, even if the recoil pulley is driven at a installed between the recoil pulley and the first drum, slow speed and in a small amount via a starter rope, a clutch mechanism which makes and releases a cou- 55 repetition of this driving for several times can cause pling between the first and second drums, flat spiral a starting force to be stored by the flat spiral spring. springs which are installed between the second drum Accordingly, an increased high-speed rotational force and spring holders so as to be wound out of the spring can be applied to the starter wheel by the spiral 2 3 EP 0 623 743 A1 4 spring, so that the engine can be started without any driving wheel 24 and rotates the driving wheel 24. failure, and energy saving is also accomplished. A first drum 26 and a second drum 36 are instal- led between the recoil pulley 16 and the starter wheel BRIEF DESCRIPTION OF THE DRAWINGS 14. 5 The first drum 26 is rotated by the recoil pulley 16 Figure 1 is a longitudinal cross sectional view of in the opposite direction (called the "anti-starting di- the power storage type recoil starter of the pres- rection") which is opposite from the starting direction ent application; of the starter wheel 14 (called the "starting direction"). Figure 2 is a perspective view thereof; The second drum 36 is rotated by the first drum 26 via Figure 3 is a right-side view of the starter wheel 10 a clutch mechanism 28 which is installed between the of the recoil starter of Figure 1 ; first drum 26 and the second drum 36. Figure 4 is a right-side cross sectional view of the When the second drum 36 is rotated, it winds out second drum and two spring holders along with flat spiral springs 32 installed between the second flat spiral springs used in the starter of Figure 1 ; drum 36 and spring holders 30 as seen in Figure 4 so Figure 5 is a right-side cross sectional view of the 15 that the rewinding force of the springs 32 is stored as ratchet used in the starter of Figure 1 ; a rotational force in the starting direction when the ro- Figure 6 is a longitudinal cross sectional view of tation of the second drum 36 in the starting direction another type of the power storage type recoil (shown by arrow B in Figure 3) is restrained by a lock- starter of the present invention; ing mechanism 34. Figure 7 is a right-side view of the one-way clutch 20 More specifically, a drive shaft 38 of the driving used in the starter of Figure 6; wheel 24 is inserted as an input shaft into a planetary Figure 8 is a right-side cross sectional view of the type speed reduction mechanism 40. The outer cir- ratchet used in the starter of Figure 6; cumference of this speed reduction mechanism 40 is Figure 9 is a right-side cross sectional view of the formed as a rotation outputting member.