Recoil starter

A recoil starter includes a reel/cam unit defined with a rope reel wound with a starter rope and urged to pivot in a direction of reeling the starter rope, and a cam in a cylindrical shape for transmitting rotation of the rope reel to an output shaft on a side of an engine. A damper unit connects the rope reel and the cam, and a reel support shaft supports the rope reel and the cam. A draw-out preventing unit restricts the reel/cam unit from being moved along the reel support shaft. One side of the cam is extended to form a cylindrical extended portion, where the rope reel is fitted to an outer side of the cylindrical extended portion. The cylindrical extended portion is rotatably fitted to an outer side of the reel support shaft.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a recoil starter for starting an engine by rotating a rope reel by pulling a starter rope wound around the rope reel, transmitting rotation of the rope reel to a cam by way of a damper unit, and rotating a drive pulley or a flywheel magnet connected to a side of the engine by rotating the cam.

2. Background Art

There has already been known a recoil starter for transmitting rotation of a rope reel rotated by pulling a starter rope to a cam, and rotating a drive pulley on a side of an engine by way of a one-directional rotating mechanism of a centrifugal ratchet or the like engaged and disengaged with and from the cam. Other than such a recoil starter integrating the rope reel and the cam, further, there is a recoil starter having a structure in which the rope reel and the cam are constituted by separate members, a damper unit is interposed between the both members to elastically connect the both members, rotation of the rope reel is transmitted to the cam by way of the damper unit to thereby absorb shock propagated to the hand by a variation in a load or the like in starting the engine.

Further, there is known a recoil starter of a damper type in which a reel support shaft in a cylindrical shape for rotatably supporting a rope reel and a cam are formed integrally with an output shaft of an engine to direct to an inner side on an axial line of the output shaft of the engine from the inner side of a starter case formed to cover a side face thereof arranged with the output shaft of the engine. An opening penetrated from the output shaft of the engine to an outer side of the starter case is formed at a center of the reel support shaft, and the output shaft of the engine is made connectable to the outer side of the starter case by way of the opening. According to the recoil starter, the rope reel and the cam rotatably supported by the reel support shaft are supported so as not to be drawn out from the reel support shaft by a draw-out preventing plate screwed to fix to the starter case. The rope reel and the cam are constituted by separate members, a diameter of the rope reel is larger than that of the cam and therefore, the draw-out preventing plate is engaged with both of the rope reel and the cam so as not to be drawn out from the reel support shaft, as disclosed in JP-A-16-60446.

SUMMARY OF THE INVENTION

However, although the rope reel and the cam are constituted by separate members, the both members need to be connected by way of a damper unit (ordinarily, a damper spring) and therefore, an operation of fitting the rope reel and the cam to the reel support shaft and an operation for locking the one end of the damper spring by the rope reel and locking other end thereof by the cam is needed and such attaching operations are troublesome.

Further, when the starter rope wound around the rope reel is cut or a portion thereof is going to be worn, the starter rope needs to be interchanged. A distal end of the starter rope is tied and a tied knot thereof is arranged at a space portion provided on an inner peripheral side from a hole formed at a groove bottom of the rope reel. The space portion is opened to the side face. According to a constitution of engaging the draw-out preventing plate with both of the rope reel and the cam, also the opening is covered by the plate and therefore, when the starter rope is interchanged, first, the draw-out preventing plate is detached, the distal end of the starter rope is grabbed to draw out from the opening of the side face, a new starter rope is wound around the rope reel, the distal end is drawn out from the opening, and the draw-out preventing knot is made to be contained in the space portion. Further, an operation of screwing the draw-out preventing plate is needed again. Therefore, the operation is troublesome and complicated.

It is a problem of the invention to provide a recoil starter capable of interchanging a starter rope without detaching a draw-out preventing plate and capable of facilitating an operation of attaching a rope reel and a cam.

In order to resolve the above-described problem, according to a first aspect of the invention, there is provided a recoil starter including: a reel/cam unit including: a rope reel wound with a starter rope one end of which is arranged on an outer side of a starter case and urged to pivot in a direction of reeling the starter rope; and a cam in a cylindrical shape for transmitting rotation of the rope reel to an output shaft on a side of an engine; a damper unit for connecting the rope reel and the cam; a reel support shaft for supporting the rope reel and the cam; and a draw-out preventing unit for restricting the reel/cam unit from being moved along the reel support shaft, wherein: one side of the cam is extended to form a cylindrical extended portion; the rope reel is fitted to an outer side of the cylindrical extended portion; an the cylindrical extended portion is rotatably fitted to an outer side of the reel support shaft.

According to a second aspect of the invention, the draw-out preventing unit is a plate attached to the starter case to be engaged with an outer peripheral edge of the rope reel of the reel/cam unit.

According to a third aspect of the invention, the draw-out preventing unit is a push nut attached to an end portion of the reel support shaft.

According to the first aspect of the invention, there is constructed a constitution in which the rope reel is fitted to the outer side of the cylindrical extended portion formed on one side of the cam, the cam and the rope reel are integrally coupled to be unitized, and the reel/cam unit is fitted to the outer side of the reel support shaft. Therefore, essential portions of the recoil starter can simply and swiftly be integrated.

Further, the draw-out preventing unit for restricting the reel/cam unit from being moved along the reel support shaft may restrict either one of the rope reel and the cam from being moved and therefore, the unit may be small-sized and can be light-weighted. Further, a knot of a distal end of the starter rope can directly be exposed to outside and therefore, when the starter rope is interchanged, a remaining portion thereof inside of the rope reel may be extracted by grabbing the knot without needing to detach the plates, and an interchanging operation can simply be carried out.

Further, the cam can be made to be small-sized and therefore, the cam can follow high speed rotation in starting. Also the plate for draw-out preventing needs not to hold the cam and therefore, the plate becomes compact, and light-weighted and cost can be reduced.

By the reel/cam unit constitution, a space of the damper unit is determined by coupling the rope reel and the cam and therefore, accuracy is improved.

According to the second aspect of the invention, an outer diameter of the cam is reduced. The plate for draw-out preventing may be engaged with the outer peripheral edge of the rope reel and need not to be engaged with the cam. Therefore, a space for taking in wind for cooling the engine can be ensured.

According to the third aspect of the invention, the push nut may be to a degree of being slightly larger than the reel support shaft and can simply and solidly be attached to the end portion of the reel support shaft.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An embodiment of the invention will be explained in reference to the drawings as follows. InFIG. 1throughFIG. 5, a recoil starter is integrated to an inner portion of a starter case1formed to be attached to one side of an engine E arranged with an output shaft C thereof. A rope reel3wound with a starter rope2one end of which is drawn out to outside of the starter case1is rotatably supported by a reel support shaft4formed to project from an inner side of the starter case1in a direction of the output shaft of the engine. An end portion on a base portion side of the starter rope2is retained to the rope reel3so as not to be drawn out therefrom. The other end is drawn out to an outer side of the starter case1, and by pulling the other end, the starter rope2is drawn out from the rope reel3, and the rope reel3is driven to rotate centering on the reel support shaft4.

The reel support shaft4is formed in a cylindrical shape and is divided into a large diameter portion4aand a small diameter portion4bby way of a middle stepped difference5.

An outer peripheral side of the rope reel3is formed with a groove6for containing the starter rope and an inner peripheral side thereof is formed with a space portion7. As shown byFIG. 2throughFIG. 4, the starter rope2is arranged with a knot8of a rope distal end at inside of the space portion7through a hole (not illustrated) formed at a bottom portion of the containing groove6.

Further, a side face of the space portion7is formed with an opening portion9for exposing the knot8and an opening portion10for engaging one end22aof a damper spring22, mentioned later.

At a side face of the rope reel3, a spiral spring11for reeling back the drawn out starter rope2to the rope reel3by rotating the rope reel3rotated by pulling the starter rope2in a reverse direction is contained in a spring case12and the spring case12is arranged on an outer side of an inner peripheral edge13formed on one side of the rope reel3. As shown byFIG. 5, an end portion11aon an outer peripheral side of the spiral spring11is retained by a hook14provided at the starter case1, further, an end portion11bon an inner peripheral side is retained by a hook15, a rotating force is accumulated in the spiral spring11when the rope reel3is rotated by pulling the starter rope2to operate such that the starter rope2is reeled back to the rope reel3by rotating the rope reel3in a reverse direction by the rotating force accumulated in the spiral spring11by letting the starter rope2go.

A cam16for transmitting rotation of the rope reel3to a side of the output shaft C on a side of the engine E is rotatably supported by a side of a front end portion of the reel support shaft4formed at the starter case1.

Next, as shown byFIG. 2, one side of the cam16is formed with a cam claw18engaged and disengaged with and from a centrifugal ratchet17formed at a drive pulley19integrally connected with the output shaft C of the engine E in a circumferential direction, and by engaging the cam claw18with the centrifugal ratchet17of the drive pulley19, rotation on a side of the cam16is transmitted to the output shaft C of the engine E by way of the drive pulley19. After starting the engine E, by rotating the drive pulley19by the engine E, the centrifugal ratchet17is constituted to be pivoted in a direction of being disengaged from the cam claw18by a centrifugal force to cut transmission of rotation between the side of the engine E and the side of the cam16.

As shown byFIG. 2, side faces of the rope reel3and the cam16opposed to each other are respectively formed with ring-like recess portions20,21to be opposed to each other, and the damper spring22constituting a damper unit is contained in the ring-like recess portions20,21. The damper spring is formed by a shape of a torsional coil spring, the one end22aof the damper spring22is contained at inside of the space portion7formed at the outer peripheral side of the ring-like recess portion20as described above, other end22bof the damper spring22is locked at inside of a bulged portion25(refer toFIG. 6) formed to project to an outer peripheral side of the ring-like recess portion21of the cam16, thereby, the rope reel3and the cam16are elastically connected in a rotational direction by way of the damper spring22and the cam16is rotated in a direction reverse to a regular rotational direction by way of the damper spring22in accordance with rotation of the rope reel3.

According to the above-described constitution, when the starter rope2is pulled to rotate the rope reel3, rotation of the rope reel3rotates the drive pulley19by way of the damper spring22, the cam16and the centrifugal ratchet17, and the output shaft C of the engine E connected to the drive pulley19is rotated, although a load of the cam16is increased by increasing a rotational load by a resistance in starting the engine, the damper spring22is twisted to absorb the load and therefore, the shock is not directly transmitted to the side of the starter rope2and the engine E can smoothly be started.

Meanwhile, as shown inFIG. 6in, a side of the cam16opposed to the cam claw18is formed with a cylindrical extended portion26. The cylindrical extended portion26is formed with two snap pieces27opposed to each other, and a front end of each snap piece27is formed with a locking projected portion28. Each snap piece27is formed elastically deformably between two slits29formed in an axial direction of the cylindrical extended portion26. Further, as shown byFIG. 1andFIG. 2, the rope reel3is fitted to an outer side of the cylindrical extended portion26, and the locking projected portion28is locked by an engaging portion30on an inner side of the inner peripheral edge13of the rope reel3. Thereby, the rope reel3and the cam16are integrally coupled to be unitized as a reel/cam unit U. The reel/cam unit U is fitted to an outer side of the reel support shaft4.

In order to integrally couple unitize the rope reel3and the cam16, first, the end portion of the starter rope2wound around the rope reel3is made to pass through a hole (not illustrated) formed at the bottom portion of the containing groove6to pass from the space portion7on the inner peripheral side through the opening portion9of the side face to make the knot8, and the starter rope2is made to be locked so as not to be drawn out from the rope reel3. Further, the damper spring22is arranged at the ring-like recess portion20on the inner peripheral side of the space portion7, and the one end22ais contained at inside of the space portion7by passing a hole (not illustrated) of an outer peripheral wall of the ring-like recess portion20. Next, the cylindrical extended portion26of the cam16is fitted to a through hole at a center of the rope reel3and the front end locking projected portion28of the snap piece27is locked by the engaging portion30on the inner peripheral side of the rope reel3. At this occasion, the other end portion22bof the damper spring22is made to pass through a groove31(refer toFIG. 6) of an outer peripheral wall of the ring-like recess portion21to be engaged with an inner side space portion32of the bulged portion14. Thereby, the rope reel3and the cam16are integrally coupled to constitute the reel/cam unit U.

In this way, the rope reel3having the starter rope and the cam16and the damper spring22are integrally coupled to unitize and therefore, the reel/cam unit U may be integrated previously, as shown byFIG. 5, an end portion11bof the spiral spring11of the spring case12may be retained by the hook15of the rope reel3and the spring case12may be fitted to an outer side of the small diameter portion4bof the reel support shaft4. At this occasion, the other end portion11aof the spiral spring may be locked by the hook14of the starter case1. The front end of the reel/cam unit U is engaged with the stepped difference5of the reel support shaft4to be positioned thereby. Therefore, main portions of the recoil starter can be integrated simply and swiftly.

Next, as shown byFIG. 1,FIG. 2andFIG. 4, a plate33in a shape of a doughnut is screwed to be fixed to the starter case1as a draw-out preventing unit, engaged with the outer peripheral edge of the rope reel3supported by the reel support shaft4to restrict the reel/cam unit U from moving in the axial direction of the reel support shaft4to prevent from being drawn out from the reel support shaft4.

According to the above-described recoil starter constitution, there is constructed a constitution in which it is not necessary to provide a flange portion for engaging with the rope reel3as in the background art and the knot8at the distal end of the starter rope2is exposed and therefore, after finishing to integrate all of parts, the starter rope2can be integrated thereafter.

The cam16can be made small-sized and therefore, the cam16can follow high speed rotation in starting. Also the plate33for draw-out preventing does not need to hold the cam16and therefore, the plate33becomes more compact, light-weight and cost can be reduced.

By the reel/cam unit constitution, a space of the damper spring22is determined by coupling the rope reel3and the cam16and therefore, accuracy is improved.

An outer diameter of the cam can be reduced and an inner diameter of the draw-out preventing plate33for holding the included part can be reduced and therefore, a space for taking in wind for cooling the engine can be ensured.

The draw-out preventing plate33is engaged only with the outer peripheral edge of the rope reel3and is not engaged with the cam16, the knot8of the distal end of the starter rope2is exposed to outside and therefore, when the starter rope2is interchanged, it is not necessary to detach the plate33and an interchanging operation can simply be carried out.

The starter case1and the draw-out preventing plate33used in an ordinary recoil starter of a type without the damper spring can be used, and therefore, the starter case1and the draw-out preventing plate33suited for the recoil starter.

Further, the reel/cam unit U is not necessarily limited to a constitution of forming the snap piece27at the extended portion26so far as the reel and the cam can be coupled integrally by fitting the rope reel to the outer side of the cylindrical extended portion26of the cam. For example, the both members may be coupled by engaging a connecting pin, not illustrated, to the both members in a state of fitting the rope reel to the extended portion26.

Next, a drive shaft D on a side of an operating apparatus connected to the output shaft C of the engine E is made to be able to be connected to an outer side of the starter case1by penetrating the reel support shaft4. The large diameter portion4aof the reel support shaft4is fitted with a pipe P supporting an operating mechanism of a cutter portion or the like of a mower and the operating apparatus is connected to the engine portion by way of the starter case1containing the recoil starter.

The output shaft C of the engine E is formed with a connecting shaft36including a through hole35having a square section at a center portion integrally with a nut member34for attaching and fixing the flywheel magnet or the drive pulley19, and the connecting shaft36is arranged at inside of a center portion of the reel support shaft4formed at the starter case1in a state of screwing the nut member34to the output shaft C for attaching the drive pulley19to the output shaft C of the engine E. The drive shaft D for driving a rotating cutter or the like of the mower is arranged at the center portion of the pipe P and by inserting an end portion of the drive shaft D into the square through hole35of the connecting shaft36, rotation of the output shaft C of the engine E is transmitted to the rotating cutter portion of the mower by way of the connecting shaft36.

Further, the draw-out preventing unit of the reel/cam unit U is not limited to the plate33in the doughnut shape. For example, the unit may be a push nut37as shown byFIG. 7andFIG. 8. The push nut37is constituted by forming a circular hole38having an inner diameter slightly smaller than the small diameter portion at a center of a circular metal plate slightly larger than an outer diameter of the small-diameter portion4bof the reel support shaft4and formed with a cut portion39radially from an inner edge of the circular hole38and when the push nut37is press-fitted to the reel support shaft4, the push nut37cannot be moved in a reverse direction.

In this way, according to the push nut37, attachment thereof is simple, the reel/cam unit U can be prevented from being drawn out by only attaching the push nut37to the reel support shaft4, a total thereof can be made to be compact and light-weight, by the reel/cam unit constitution, the space of the damper spring22is determined by coupling the rope reel3and the cam16, accuracy is improved and therefore, accuracy of positioning the push nut37can be alleviated.

Next,FIG. 9andFIG. 10show an example4-constituting a power spring in place of the damper spring, a containing portion41of the power spring40is formed between a side face plate of the rope reel3and a side face plate of the cam16, an outer peripheral end portion40athereof is locked by a locking groove42of the rope reel3and an inner peripheral end portion53bis locked by a locking groove43of the cam16.

Also in this case, the reel/cam unit U integrally coupled with the rope reel3and the cam16is constituted by fitting the cylindrical extended portion26of the cam16to the through hole at the center of the rope reel3and locking the front end locking projected portion28by the engaging portion30of the rope reel3. Further, the plate33in the doughnut shape is screwed to be fixed to the starter case1as the draw-out preventing unit, the reel/cam unit U is restricted from being moved in the axial direction of the reel support shaft4by being engaged with the outer peripheral edge of the rope reel3to prevent the reel/cam unit U from being drawn out from the reel support shaft4. Further, the knot8at the distal end of the starter rope2contained at inside of the rope reel3is exposed to the inner peripheral side of the draw-out preventing plate33.

According to the above-described constitution, the draw-out preventing plate33does not need to hold the cam16and therefore, the plate33becomes compact, and light-weight and cost can be reduced.

The knot8of the distal end of the starter rope2is directly exposed to outside and therefore, when the starter rope2is interchanged, it is not necessary to detach the plate33and interchanging operation can simply be carried out.

Further, even when the recoil starter needs to be disassembled since the spiral spring11is cut, the reel/cam unit U can be detached as it is and therefore, there is not a concern that the power spring40jumps. When not unitized, only the cam16is detached precedingly and there is a possibility that the power spring40jumps.