Patent Publication Number: US-6901899-B2

Title: Recoil starter

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a recoil starter, wherein a recoil rope is pulled to rotate a rope reel so that a rotation of the rope reel is transmitted to a drive pulley coupled to a crankshaft of an engine via a clutch mechanism such as a centrifugal clutch to thereby rotate the drive pulley, resulting in the engine being started. 
   2. Description of the Related Art 
   Among recoil starters where a rope reel is rotated by pulling a recoil rope wound around the rope reel, and a rotation of a cam rotated by a rotation of the rope reel is transmitted to a rotating member such as a flywheel magnet or a drive pulley that is coupled to a crankshaft of an engine via a clutch mechanism such as a centrifugal clutch, so that the crankshaft of the engine is rotated to start the engine, a recoil starter is known which is so constructed that a cushioning and force accumulating means is disposed between the rope reel and the cam so as to prevent shock due to abrupt load fluctuations on the engine side from being transmitted to the rope reel side and so as to facilitate starting of the engine by accumulating a rotational force of the rope reel in the cushioning and force accumulating means and releasing the rotational force accumulated in the cushioning and force accumulating means (see, e.g., Japanese Patent Application Laid-Open Publication No. 2001-132591). 
   In this conventional recoil starter, the rope reel rotated by pulling the recoil rope, the cam that transmits the rotation to the drive pulley coupled to the crankshaft of the engine via the clutch mechanism and a spring case that houses a spring as the cushioning and force accumulating means are each rotatably supported by a shaft formed within a casing. Additionally, a one-way ratchet mechanism is provided between the rope reel and the spring case such that the rotation of the rope reel in an engine starting direction is transmitted to the spring case. When the rope reel is rotated by pulling the recoil rope, the spring case is rotated together via the one-way ratchet mechanism, transmitting the rotation of the rope reel to the drive pulley via the spring case. When the drive pulley stops rotating due to a starting resistance of the engine, a rotational force of the rope reel is accumulated in the spring. Further, a one-way clutch is provided between the shaft and the spring case to prevent rotation of the spring case in the opposite direction. 
   In this conventional recoil starter, the spring case housing the cushioning and force accumulating means or spring, the rope reel around which the recoil rope is wound and the drive pulley for transmitting the rotational force to the crankshaft of the engine are each supported by the shaft within the casing; the one-way ratchet mechanism is provided between the rope reel and the spring case so as to transmit the rotation of the rope reel in the engine starting direction to the spring case; and the one-way clutch is provided between the spring case and the shaft to allow rotation of the spring case only in the engine starting direction, with the result that the manufacturing costs of the recoil starter are increased due to a large number of components required and a complex configuration of the components and a reduction in size and weight of the recoil starter is precluded due to large outer dimensions of the recoil starter, and particularly axial dimensions thereof. 
   SUMMARY OF THE INVENTION 
   The present invention has been made in view of the foregoing problems. 
   Accordingly, it is an object of the present invention to provide a recoil starter that is equipped with a cushioning and force accumulating means and capable of readily starting an engine and that can achieve not only a reduction in the number of components and the manufacturing costs thereof but also a reduction in size and weight thereof. 
   In accordance with the present invention, there is provided a recoil starter. The recoil starter comprises: a casing having a reel shaft formed therein and adapted to be mounted to an engine; a rope reel rotatably supported on the reel shaft and provided on an outer periphery thereof with a drum portion around which a recoil rope is wound; a recoil spring for rotationally urging the rope reel in a direction in which the recoil rope is rewound; a cam engageable, via a clutch mechanism, with a drive pulley coupled to the engine, for transmitting a rotation thereof to the drive pulley; and a cushioning and force accumulating means interposed between the rope reel and the cam, a rotational force of the rope reel accumulated in the cushioning and force accumulating means being transmitted via the cam to the drive pulley, to thereby start the engine; wherein a ratchet mechanism is provided between the rope reel and the cam such that, when the rope reel is rotated in an engine starting direction, the ratchet mechanism uncouples the rope reel and the cam from each other, and when the rope reel is rotated in the direction opposite to the engine starting direction by the rotational force accumulated in the recoil spring, the ratchet mechanism couples the rope reel and the cam to each other so that the cam is rotated together with the rope reel in said opposite direction. 
   Preferably, the clutch mechanism comprises a centrifugal clutch disposed on the drive pulley and provided with a centrifugal ratchet that operates to disengage from the cam by a centrifugal force. 
   Alternatively, the clutch mechanism may comprise a one-way clutch provided with a ratchet that is provided on the cam so as to engage with or disengage from an engagement portion formed on the drive pulley. 
   In a preferred embodiment of the present invention, the cushioning and force accumulating means comprises a spiral spring that has one end thereof held on the rope reel and the other end thereof held on the cam. 
   In a preferred embodiment of the present invention, the ratchet mechanism includes a ratchet member having a ratchet pawl integrally formed thereon to be engageable with an engagement member formed on an outer periphery of the cam, and an operating member having an operating piece for operating the ratchet member to rotate it, the ratchet member and the operating member each being pivotally supported on a side surface of an outer peripheral portion of the rope reel; the operating piece is formed on the operating member so as to pivotally rotate the operating member by engaging with one of cutout grooves formed on an inner circumference surface of an outer wall of the casing; when the rope reel is rotated in the engine starting direction, the operating piece of the operating member engages with one of the cutout grooves, to thereby pivotally rotate the operating member in a direction in which the ratchet pawl is disengaged from the engagement member; and when the rope reel is rotated in the direction in which the recoil rope is rewound, the operating piece of the operating member engages with one of the cutout grooves, to thereby pivotally rotate the operating member in a direction in which the ratchet pawl of the ratchet member is engaged with the engagement member of the cam. 
   The ratchet mechanism may comprise a ratchet member swingably supported on a side surface of an outer peripheral portion of the rope reel and provided with a ratchet pawl engageable with an engagement member formed on an outer periphery of the cam, and a biasing means for biasing the ratchet member such that the ratchet member comes into contact with and slides on an inner circumferential surface of an outer wall of the casing; when the rope reel is rotated in the engine starting direction, the ratchet member swings due to friction between the ratchet member and the inner circumferential surface of the casing such that the ratchet pawl is disengaged from the engagement member of the cam; and when the rope reel is rotated in the direction in which the recoil rope is rewound, the ratchet member swings due to the friction between the ratchet member and the inner circumferential surface of the casing such that the ratchet pawl is engaged with the engagement member of the cam. 
   Alternatively, the ratchet mechanism may comprise a ratchet member pivotally supported on a side surface of the rope reel via a pivot and provided at one end thereof with a ratchet pawl engageable with an engagement member formed on an outer periphery of the cam, and a biasing spring piece having a curved shape and supported at opposite ends thereof on the ratchet member while a curved portion of the biasing spring piece is kept in sliding contact with an inner circumferential surface of an outer wall of the casing; when the rope reel is rotated in the engine starting direction, the ratchet pawl is disengaged from the engagement member of the cam due to a sliding resistance between the curved portion of the biasing spring piece and the inner circumferential surface of the casing; and when the rope reel is rotated in the direction in which the recoil rope is rewound, the ratchet member is pivotally rotated about the pivot due to the sliding resistance between the curved portion of the biasing spring piece and the inner circumferential surface of the casing such that the ratchet pawl is engaged with the engagement member of the cam. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, aspects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a sectional side elevation view showing a recoil starter according to an embodiment of the present invention; 
       FIG. 2  is an exploded perspective view showing a configuration of major components of the recoil starter shown in  FIG. 1 ; 
       FIG. 3  is a front view showing a clutch mechanism of the recoil starter shown in  FIG. 1 ; 
       FIG. 4  is a sectional view of the recoil starter taken along line A—A of  FIG. 1 ; 
       FIG. 5A  is a perspective view showing a ratchet mechanism used in the recoil starter of  FIG. 1  in a state where a rope reel is rotated in an engine starting direction, and  FIG. 5B  is a perspective view showing the ratchet mechanism in a state where the rope reel is rotated in a direction opposite to the engine starting direction; 
       FIG. 6  is a sectional view, similar to  FIG. 4 , showing the state in which the ratchet member operates immediately after the rope reel is rotated in the engine starting direction; 
       FIG. 7  is a sectional view, similar to  FIG. 6 , showing the state in which rotational force is transmitted to a drive pulley as the result of a cam engaging with the clutch mechanism; 
       FIG. 8  is a sectional view, similar to  FIG. 7 , showing the state in which rotational force is accumulated in a cushioning and force accumulating means due to a rotation of the rope reel after the cam is inhibited from rotating by a starting resistance of the engine; 
       FIG. 9  is a sectional view, similar to  FIG. 4 , showing the state in which the ratchet mechanism operates immediately after the rope reel is rotated in the opposite direction; 
       FIG. 10  is a sectional view, similar to  FIG. 4 , showing the state in which the rope reel and the cam are rotated together in the opposite direction by the ratchet member; 
       FIG. 11  is a sectional view, similar to  FIG. 10 , showing the state in which the ratchet mechanism uncouples the rope reel from the cam as the result of the rope reel being rotated again in the engine starting direction; 
       FIG. 12  is a perspective view showing a ratchet mechanism in accordance with another embodiment of the present invention; 
       FIG. 13  is a front view showing the ratchet mechanism shown in  FIG. 12 ; 
       FIG. 14A  is a perspective view showing the ratchet mechanism of  FIG. 12  in a state where a rope reel is rotated in the engine starting direction, and  FIG. 14B  is a perspective view showing the ratchet mechanism in a state where the rope reel is rotated in the direction opposite to the engine starting direction; 
       FIG. 15  is a perspective view showing a ratchet mechanism in accordance with still another embodiment of the present invention; 
       FIG. 16  is a front view showing the ratchet mechanism shown in  FIG. 15 ; 
       FIG. 17A  is a perspective view showing the ratchet mechanism of  FIG. 15  in a state where a rope reel is rotated in the engine starting direction, and  FIG. 17B  is a perspective view showing the ratchet mechanism in a state where the rope reel is rotated in the direction opposite to the engine starting direction; 
       FIG. 18  is a perspective view showing a ratchet mechanism in accordance with a further embodiment of the present invention; 
       FIG. 19  is a front view showing the ratchet mechanism shown in  FIG. 18 ; 
       FIG. 20A  is a perspective view showing the ratchet mechanism of  FIG. 18  in a state where a rope reel is rotated in the engine starting direction, and  FIG. 20B  is a perspective view showing the ratchet mechanism in a state where the rope reel is rotated in the direction opposite to the engine starting direction; and 
       FIG. 21  is a sectional side elevation view showing a clutch mechanism according to a still further embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Embodiments of the present invention will now be described below with reference to the accompanying drawings. 
   Referring first to  FIGS. 1  to  11 , an embodiment of a recoil starter according to the present invention is illustrated. A recoil starter of the illustrated embodiment, as shown in  FIGS. 1 and 2 , includes a casing  1  that internally houses main components of the recoil starter and is formed to be mounted to an engine so as to cover a side surface portion of the engine. A reel shaft  2  is formed, so as to be opposite to a crankshaft (not shown) of the engine, on an inner side surface of the casing  1 . A rope reel  4  around which a recoil rope  3  is wound is rotatably attached to the reel shaft  2 . The recoil rope  3  that is wound around a drum portion  4   a  formed on an outer periphery of the rope reel  4  has one end thereof fixed to the rope reel  4  and the other end thereof drawn to the outside of the casing  1 , so that the rope reel  4  is driven and rotated about the reel shaft  2  by pulling the other end of the recoil rope  3 . 
   A recoil spring  5  is provided between a side surface of the rope reel  4  and an outer peripheral surface of a base portion of the reel shaft  2  formed on the inner surface of the casing  1 . The recoil spring  5  is arranged so as to rewind the recoil rope  3 , which has been unwound from the drum portion  4   a  of the rope reel  4  rotated in an engine starting direction by pulling the recoil rope  3 , onto the rope reel  4  by rotating the rope reel  4  in the opposite direction. The recoil spring  5  is fixed to the reel shaft  2  at one end on an inner peripheral side thereof and to the rope reel  4  at the other end on an outer peripheral side thereof. When the rope reel  4  is rotated in the engine starting direction by pulling the recoil rope  3 , a rotational force is accumulated in the recoil spring  5 . When the recoil rope  3  is released, the rope reel  4  is rotated in the opposite direction by the rotational force accumulated in the recoil spring  5 , so that the recoil rope  3  drawn to the outside of the casing  1  is rewound onto the rope reel  4 . 
   A cam  9  is rotatably mounted to a distal end side of the reel shaft  2 . The cam  9  has cam pieces  8  that are formed on an outer circumferential surface thereof so as to engage with a clutch mechanism  7  provided on a drive pulley  6  that is attached to the crankshaft of the engine. The cam  9  and the rope reel  4  are rotatably supported together by the reel shaft  2  with a screw  10  screwed into an end portion of the reel shaft  2 . As shown in  FIGS. 1 and 3 , the clutch mechanism  7  provided on the drive pulley  6  is configured as a centrifugal clutch mechanism having centrifugal ratchets  7   a  that are rotationally movable and biased by respective springs (not shown) toward the cam pieces  8  formed on the cam  9 . When the cam  9  is rotated in the engine starting direction, the centrifugal ratchets  7   a  engage with the respective cam pieces  8 , to thereby rotate the drive pulley  6  in the engine starting direction. When the drive pulley  6  is rotated via the crankshaft after the engine is started, the centrifugal ratchets  7   a  rotationally move due to a centrifugal force against spring-biased force and disengage from the cam pieces  8 , so that rotation of the engine side can be prevented from being transmitted to the recoil starter side. 
   As shown in  FIG. 1 , a recess  11  is formed on the other side surface of the rope reel  4 . The recess  11  receives a force accumulating spiral spring  12  that constitutes a cushioning and force accumulating means. The force accumulating spring  12  is housed in a spring case  13 , and the spring case  13  is received in the recess  11  and fixed to the rope reel  4 . The force accumulating spring  12  is fixed to the spring case  13  at one end on an outer peripheral side thereof and engages with the cam  9  at the other end on an inner peripheral side thereof. Thus, the rope reel  4  and the cam  9  are coupled via the force accumulating spring  12 , so that a rotation of the rope reel  4  is transmitted to the cam  9  via the force accumulating spring  12 . Relative rotation takes place between the cam  9  and the rope reel  4  as the result of inhibiting the rotation of the cam  9  due to a starting resistance of the engine, so that a rotational force of the rope reel  4  is accumulated in the force accumulating spring  12 . 
   As shown in  FIGS. 1 and 2 , a ratchet mechanism  14  is provided between the cam  9  and the rope reel  4  such that the ratchet mechanism  14  disengages from the cam  9  when the rope reel  4  is rotated in the engine starting direction, whereas the ratchet mechanism  14  engages with the cam  9  when the rope reel  4  is rotated in the direction opposite to the engine starting direction, to thereby rotate the cam  9  and the rope reel  4  together in the direction opposite to the engine starting direction. The ratchet mechanism  14  comprises a ratchet member  16  that is pivotally fixed on the side surface adjacent to an outer peripheral edge of the rope reel  4  by a pivot  15  so as to be rotationally movable and an operating member  18  that is pivotally fixed by a pivot  17  formed in the vicinity of the pivot  15  so as to be rotationally movable. The cam  9  and the rope reel  4  are rotated together in the opposite direction as a ratchet pawl  19  formed on the ratchet member  16  engages with any one of a plurality of engagement surfaces  21  that are formed on an outer periphery of an engagement member  20  formed so as to protrude from the outer circumferential surface of the cam  9  and that face in the engine starting direction. 
   As shown in  FIG. 5A , a spring piece  22  is integrally formed on the ratchet member  16  so as to protrude in a radial direction such that the spring piece  22  allows the ratchet pawl  19  to engage with or disengage from the engagement surfaces  21  on the engagement member  20  of the cam  9  by rotationally actuating the ratchet member  16 . An actuating piece  23  and an operating piece  24  are integrally formed on the operating member  18  so as to protrude in a radial direction. The actuating piece  23  engages with the spring piece  22  to move the ratchet member  19  rotationally. The operating piece  24  operates to rotationally move the operating member  18 . As shown in  FIG. 4 , the operating piece  24  of the operating member  18  is arranged so as to slide on an inner circumferential surface  25  of an outer wall  1   a  formed on the casing  1 . The operating piece  24  is adapted to engage with each of a plurality of cutout grooves  26  formed on the inner circumferential surface  25  equidistantly in a circumferential direction so as to rotationally move the operating member  18 . 
   When the rope reel  4  is rotated in the engine starting direction, the operating piece  24  of the operating member  18  is rotationally moved so as to be inclined backward in the rotational direction of the rope reel  4 , to thereby cause the actuating piece  23  of the operating member  18  to move the spring piece  22  of the ratchet member  16  radially inward, with the result that the ratchet pawl  19  disengages from the engagement member  20  of the cam  9  as indicated by solid lines in FIG.  4  and shown in FIG.  5 A. At this time, the ratchet pawl  19  comes into contact with a stopper pin  27  provided on the back side of the ratchet pawl  19 , so that the rotational movement angle of the ratchet member  16  is restricted. When the rope reel  4  is rotated in the direction opposite to the engine starting direction, the operating piece  24  of the operating member  18  engages with one of the cutout grooves  26  and is rotationally moved so as to be inclined backward in the rotational direction of the rope reel  4 , to thereby cause the actuating piece  23  of the operating member  18  to move the spring piece  22  of the ratchet member  16  radially outward, with the result that the ratchet pawl  19  engages with one of the engagement surfaces  21  of the engagement member  20  of the cam  9  as indicated by dashed lines in FIG.  4  and shown in FIG.  5 B. 
   The operation of the recoil starter in the illustrated embodiment will be described with reference to  FIGS. 6  to  11 . When the recoil rope  3  is pulled to rotate the rope reel  4  in the engine starting direction, the operating piece  24  of the operating member  18  engages with one of the cutout grooves  26  formed on the outer wall  1   a  of the casing  1 , whereby the operating piece  24  is inclined backward in the rotational direction, causing the actuating piece  23  of the operating member  18  to move the spring piece  22  of the ratchet member radially inward, resulting in the ratchet pawl  19  disengaging from the engagement member  20  of the cam  9  as shown in FIG.  6 . As the rope reel  4  is rotated, the cam  9  is rotated via the force accumulating spring  12 , engaging the cam pieces  8  of the cam  9  with the centrifugal ratchets  7   a , to thereby rotate the drive pulley  6 , so that the crankshaft of the engine coupled to the drive pulley  6  is rotated as shown in FIG.  7 . 
   When the rotational load of the drive pulley  6  becomes large due to the starting resistance of the engine, the drive pulley  6  is inhibited from rotating, so that the rotation of the cam  9  of which the cam pieces  8  are engaged with the centrifugal ratchets  7   a  is prevented. However, although the cam  9  is prevented from rotating, the rope reel  4  is further rotated as shown in  FIG. 8 , and the force accumulating spring  12  is wound to accumulate a rotational force of the rope reel  4  in the force accumulating spring  12 . Shock caused by abrupt load fluctuations on the engine side is cushioned by the force accumulating spring  12 . In this process, the operating piece  24  of the operating member  18  is rotated together with the rope reel  4  while sliding on the inner circumferential surface  25  of the outer wall  1   a  of the casing  1 , whereas the ratchet pawl  19  of the ratchet member  16  is kept in contact with the stopper pin  27  and disengaged from the engagement member  20  of the cam  9  via the spring piece  22  engaging with the actuating piece  23  of the operating member  18 . 
   When the recoil rope  3  being pulled is released under this condition, the rope reel  4  is rotated in the direction opposite to the engine starting direction due to the rotational force accumulated in the recoil spring  5 , resulting in the recoil rope  3  being rewound onto the rope reel  4 . When the rope reel  4  is rotated in the opposite direction as shown in  FIG. 9 , the operating piece  24  of the operating member  18  engages with one of the cutout grooves  26  formed on the outer wall  1   a  of the casing  1 , so that the operating piece  24  is inclined backward in the rotational direction of the rope reel  4 , whereby the ratchet member  16  is pivotally turned counterclockwise through rotating of the operating member  18  to engage the ratchet pawl  19  with one of the engagement surfaces  21  of the engagement member  20  of the cam  9 , with the result that the cam  9  and the rope reel  4  are rotated together in the opposite direction. This allows the force accumulating spring  12  to rotate together with the rope reel  4  and the cam  9  in the opposite direction, with the rotational force accumulated in the force accumulating spring  12 . As shown in  FIG. 10 , the centrifugal clutch  7  engaging with the cam  9  permits rotation of the cam  9  in the opposite direction due to sloping surfaces  8   a  formed on the back sides of the cam pieces  8 . Thus, it is possible to rewind the recoil rope  3  onto the rope reel  4  while maintaining the rotational force accumulated in the force accumulating spring  12 . 
   When the rope reel  4  is rotated again in the engine starting direction by pulling the recoil rope  3 , the cam  9  is rotated via the force accumulating spring  12  having the rotational force accumulated therein, so that the cam pieces  8  of the cam  9  engage with the centrifugal ratchets  7   a , to thereby transmit the starting resistance of the engine to the cam  9  again, resulting in the cam  9  being inhibited from rotating as shown in FIG.  11 . As the result of the rotation of the rope reel  4 , the operating piece  24  of the operating member  18  engages with one of the cutout grooves  26 , rotationally moving the operating member  18  so as to be inclined backward in the rotational direction, to thereby cause the actuating piece  23  to rotationally move the spring piece  22  of the ratchet member  16 , resulting in the ratchet pawl  19  being disengaged from the engagement member  20  of the cam  9 . As the rope reel  4  is further rotated by pulling the recoil rope  3 , the rotational force is further accumulated in the force accumulating spring  12 . When the rotational force accumulated in the force accumulating spring  12  exceeds the starting resistance of the engine, the rotational force of the rope reel  4  and that accumulated in the force accumulating spring  12  are released, so that the resultant rotational force is transmitted to the drive pulley  6  via the cam  9 , abruptly rotating the crankshaft to start the engine. 
   Referring now to  FIGS. 12  to  14 B, another embodiment of a recoil starter according to the present invention is illustrated. In a recoil starter of the illustrated embodiment, a ratchet mechanism  30  provided between the rope reel  4  and the cam  9  comprises a ratchet member  32  pivotally mounted to a pivot  31  formed on the side surface of the outer peripheral portion of the rope reel  4  and an operating member  34  pivotally fixed to a pivot  33  formed in the vicinity of the pivot  31 . A ratchet pawl  35  integrally formed on the ratchet member  32  engages with one of the engagement surfaces  21  of the engagement member  20  formed on the outer periphery of the cam  9 , so that the cam  9  and the rope reel  4  are rotated together in the direction opposite to the engine starting direction. 
   The ratchet member  32  is rotationally biased by a spring  36  in a direction in which the ratchet pawl  35  of the ratchet member  32  is brought into contact with the engagement member  20  of the cam  9 . Further, an operating piece  37  is integrally formed on the ratchet member  32  so as to operate the ratchet member  32  to be pivotally turned. An actuating piece  38  and an operating piece  39  are integrally formed on the operating member  34  such that the actuating piece  38  rotates the ratchet member  32  by engaging with the operating piece  37  while the operating piece  39  slides on the inner circumferential surface  25  of the outer wall  1   a  of the casing  1 . Other configuration is the same as that in the aforementioned embodiment. 
   In the recoil starter thus constructed, when the rope reel  4  is rotated in the engine starting direction, the operating piece  39  engages with one of the cutout grooves  26  formed on the outer wall  1   a , whereby the operating piece  39  is inclined backward in the rotational direction of the rope reel  4  to pivotally turn the operating member  34 , causing the actuating piece  38  of the operating member  34  to engage with the operating piece  37  of the ratchet member  32  and pivotally turn the ratchet member  32  in a direction in which the ratchet pawl  35  is disengaged from the engagement member  20  of the cam  9  as indicated by solid lines in FIG.  13  and shown in FIG.  14 A. When the rope reel  4  is rotated in the direction opposite to the engine starting direction, the operating piece  39  engages with one of the cutout grooves  26  formed on the outer wall  1   a , pivotally moving the operating member  34 , whereby the actuating piece  38  of the operating member  34  is disengaged from the operating piece  37  of the ratchet member  32 , so that the ratchet member  32  is pivotally turned by a biased force of the spring  36  in a direction in which the ratchet pawl  35  engages with the engagement member  20  of the cam  9 , with the result that the cam  9  and the rope reel  4  are rotated together in the opposite direction as indicated by dashed lines in FIG.  13  and shown in FIG.  14 B. 
   Referring now to  FIGS. 15  to  17 B, a further embodiment of a recoil starter according to the present invention is illustrated. In a recoil starter of the illustrated embodiment, a ratchet mechanism  40  provided between the rope reel  4  and the cam  9  comprises a ratchet member  42  swingably supported by a pivot  41  that is formed on the side surface of the outer peripheral portion of the rope reel  4 . A ratchet pawl  43  formed on the ratchet member  42  engages with one of the engagement surfaces  21  of the engagement member  20  formed on the outer periphery of the cam  9 , so that the cam  9  and the rope reel  4  are rotated together in the direction opposite to the engine starting direction. 
   As shown in  FIG. 17A , an elongated opening  44  is formed in the ratchet member  42 . The pivot  41  is loosely fit into the opening  44  to support the ratchet member  42  such that the ratchet member  42  can move along the circumference of the rope reel  4  within the opening  44  and rotationally move about the pivot  41 . Further, opposite end portions of the inner side of the ratchet member  42  along the circumference are pressed and biased toward the inner circumferential surface  25  of the outer wall  1   a  of the casing  1  by a leaf spring  45  that constitutes a biasing means. The pressing force of the leaf spring  45  allows one of the outer end edges of the ratchet member  42  along the circumference to come into contact with and slide on the inner circumferential surface  25  of the outer wall  1   a . Other configuration is the same as that in the aforementioned embodiments. 
   In the illustrated embodiment thus constructed, when the rope reel  4  is rotated in the engine starting direction, the ratchet member  42  is moved backward in the rotational direction of the rope reel  4  due to a frictional resistance acting on the outer end edge of the ratchet member  42  which is in contact with the inner circumferential surface  25  of the outer wall  1   a  and the ratchet pawl  43  is swung in a direction in which the ratchet pawl  43  is disengaged from the engagement member  20  of the cam  9  due to pressing action of the leaf spring  45  as indicated by solid lines in FIG.  16  and shown in FIG.  17 A. When the rope reel  4  is rotated in the direction opposite to the engine starting direction, the ratchet member  42  is moved backward in the rotational direction due to the frictional resistance acting on the outer end edge of the ratchet member  42  which is in contact with the inner circumferential surface  25  of the outer wall  1   a  and the ratchet pawl  43  is swung in a direction in which the ratchet pawl  43  is engaged with the engagement member  20  of the cam  9  due to pressing action of the leaf spring  45  as indicated by dashed lines in FIG.  16  and shown in  FIG. 17B , resulting in the cam  9  and the rope reel  4  being rotated together in the opposite direction. 
   Referring now to  FIGS. 18  to  20 B, still another embodiment of a recoil starter according to the present invention is illustrated. In a recoil starter of the illustrated embodiment, a ratchet mechanism  50  provided between the rope reel  4  and the cam  9  comprises a ratchet member  52  pivotally supported by a pivot  51  that is formed on the side surface of the outer peripheral portion of the rope reel  4 . A ratchet pawl  53  formed at a distal end of the ratchet member  52  engages with one of the engagement surfaces  21  of the engagement member  20  formed on the outer periphery of the cam  9 , so that the cam  9  and the rope reel  4  are rotated together in the direction opposite to the engine starting direction. 
   The ratchet mechanism  50  is further provided with a biasing spring piece  54  that is formed by curving a linear elastic material in the form of a circular arc. The biasing spring piece  54  is supported on the ratchet member  52  while opposite end portions  54   b  and  54   c  thereof, which are formed by bending them vertically from the opposite ends of a curved portion  54   a  thereof, are respectively inserted in holes  52   a  and  52   a  formed in the ratchet member  52  on the opposite sides of the pivot  51 . The back side of the curved portion  54   a  of the biasing spring piece  54  is pressed against the inner circumferential surface  25  of the outer wall  1   a  of the casing  1  so as to slide on the inner circumferential surface  25 . When the curved portion  54   a  of the biasing spring piece  54  is deformed due to a sliding resistance between the curved portion  54   a  and the inner circumferential surface  25  of the outer wall  1   a , the ratchet member  52  is rotated about the pivot  51  by the end portions  54   b  and  54   c.    
   More specifically, when the recoil rope  4  is rotated in the engine starting direction shown by the arrow indicated by solid lines in  FIG. 19  by pulling the recoil rope  3 , the curved portion  54   a  of the biasing spring piece  54  that rotates together with the rope reel  4  is slid on the inner circumferential surface  25  of the casing  1 , whereby the curved portion  54   a  is deformed backward in the rotational direction of the rope reel  4  due to the sliding resistance and the end portion  54   b  is displaced radially inward while the end portion  54   c  is displaced radially outward. This allows the ratchet member  52  to rotate about the pivot  51 , resulting in the ratchet pawl  53  being disengaged from the engagement member  20  of the cam  9 . When the recoil rope  4  is rotated in a direction in which the recoil rope  3  is rewound as shown by the arrow indicated by dashed lines in  FIG. 19 , the end portion  54   b  of the biasing spring piece  54  is displaced radially outward while the end portion  54   c  thereof is displaced radially inward, whereby the ratchet member  52  is pivotally rotated so as to make the ratchet pawl  53  engage with one of the engagement surfaces  21  of the engagement member  20  of the cam  9 , resulting in the cam  9  and the rope reel  4  being rotated together. Other configuration is the same as that in the aforementioned embodiments. 
   In the illustrated embodiment, the biasing spring piece  54  is formed of a linear elastic material. Alternatively, the biasing spring piece may be formed from an elastic piece in the form of a thin plate by curving it and holding opposite end portions of the elastic piece onto the ratchet member  52  on the opposite sides of the rotational axis of the pivot  51  such that the same action can be performed as that in the illustrated embodiment. 
   Referring now to  FIG. 21 , a still further embodiment of a recoil starter according to the present invention is illustrated. In the embodiments described above, the clutch mechanism  7  is so constructed that the clutch mechanism  7  is operated by a centrifugal force produced by the rotation of the drive pulley  6  and is designed to transmit the rotation of the cam  9  to the engine side through the centrifugal ratchets  7   a  that are provided on the drive pulley  6  coupled to the crankshaft of the engine so as to engage with the cam pieces  8  formed on the cam  9 . In the embodiment shown in  FIG. 21 , the clutch mechanism  7  comprises a one-way clutch  60  constructed to transmit a rotation of the cam  9  via a ratchet  61  provided on the cam  9  to the engine side. The ratchet  61  is pivotally arranged on the cam  9  so as to be engaged with and disengaged from an engagement portion  62  formed on an inner peripheral surface of the drive pulley  6  that is coupled to the engine. Other configuration is the same as that in the aforementioned embodiments. 
   In the one-way clutch  60 , the ratchet  61  having a protrusion  63  formed on the top surface thereof is held at one end thereof on the cam  9  so as to be rotatable. A ratchet guide  65 , which has a guide groove  64  formed on a surface thereof opposite to the ratchet  61 , is mounted to the reel shaft  2  so as to be rotatable. The ratchet guide  65  is elastically fitted around a cylindrical portion  10   a  of a screw  10  that is screwed into the reel shaft  2 , so that a predetermined rotational resistance is applied to the ratchet guide  65  relative to the screw  10 . The protrusion  63  of the ratchet  61  is loosely fitted into the guide groove  64  of the ratchet guide  65 . When the cam  9  is rotated, the ratchet  61  is rotated together with the cam  9 , so that the protrusion  63  of the ratchet  61  engages with the guide groove  64  of the ratchet guide  65  to which the rotational resistance is applied, whereby the ratchet  61  is rotated about the one end to cause a distal end portion of the ratchet  61  to outwardly project and engage with the engagement portion  62  of the drive pulley  6 , resulting in a rotation of the cam  9  in the engine starting direction being transmitted to the drive pulley  6 . When the cam  9  rotates in the opposite direction, the protrusion  63  of the ratchet  61  engages with the guide groove  64 , to thereby retract the distal end portion of the ratchet  61  radially inward, resulting in the transmission of rotation being inhibited. 
   The recoil starter in each of the above described embodiments enables to readily start the engine without transmission of shock to the recoil rope  3  due to a cushioning and force accumulating action of the force accumulating spring  12  by pulling the recoil rope  3  a relatively long distance. Also, a rotational force can be accumulated in the force accumulating spring  12  by pulling the recoil rope  3  a short distance several times. Therefore, the position at which force is applied to the recoil rope  3  can be adjusted, to thereby facilitate, in association with the cushioning action, starting the engine with a lesser shock. 
   According to the present invention, starting of the engine can be carried out while shock is absorbed through the cushioning and force accumulating action by pulling the recoil rope a relatively long distance. Starting of the engine can also be carried out while shock is more effectively absorbed through the cushioning and force accumulating action by pulling the recoil rope a short distance several times. Therefore, the distance which the recoil rope is pulled and the position at which force is applied to the recoil rope can be adjusted, to thereby enable, in association with the cushioning action, to easily start the engine with a lesser shock. 
   In addition, according to the present invention, the ratchet mechanism is provided between the rope reel and the cam such that the ratchet mechanism is disengaged from the cam when the rope reel is rotated in the engine starting direction and the ratchet mechanism is engaged with the cam when the rope reel is rotated in the opposite direction, so that the cam and the rope reel rotate together. Such construction requires neither a rotating member such as a spring case that rotates independently nor a one-way clutch mechanism that permits rotation of the rotating member only in one direction between the rope reel and the cam, unlike the prior art, resulting in a reduction in the manufacturing costs of the recoil starter and a reduction in size and weight thereof being achieved. 
   In one embodiment of the present invention, the clutch mechanism provided between the drive pulley and the cam comprises the centrifugal clutch disposed on the drive pulley and provided with the centrifugal ratchets. Therefore, when the crankshaft rotates as the result of the engine being started, the drive pulley holding thereon the centrifugal ratchets is rotated by the engine, so that the centrifugal ratchets are disengaged from the cam due to a centrifugal force, whereby rotation on the engine side is prevented from being transmitted to the cam and the rope reel side. 
   Moreover, in one embodiment of the present invention, the clutch mechanism provided between the drive pulley and the cam comprises the one-way clutch that includes the ratchet provided on the cam so as to engage with or disengage from the engagement portion formed on the drive pulley. Therefore, when the cam is rotated in the engine starting direction by pulling the recoil rope, transmission of rotation is reliably performed; and when the cam is rotated in the opposite direction and after the engine is started, transmission of rotation between the drive pulley and the cam is positively inhibited, whereby rotation on the engine side is prevented from being transmitted to the cam and the rope reel side. 
   Additionally, in one embodiment of the present invention, the cushioning and force accumulating means comprises the spiral spring that has one end thereof held on the rope reel and the other end thereof held on the cam, so that the cushioning capability can be set to be high, allowing the engine to be smoothly started with high cushioning effect. The force accumulating capability can also be set to be high, so that a rotational force required to start the engine can be sufficiently accumulated. 
   Furthermore, in one embodiment of the present invention, the ratchet mechanism provided between the rope reel and the cam comprises the ratchet member pivotally supported on the side surface of the outer peripheral portion of the rope reel and the operating member that operates the ratchet member to rotate it, wherein the operating piece is formed on the operating member so as to pivotally rotate the operating member by engaging with one of the cutout grooves formed on the inner circumference surface of the outer wall of the casing. Such construction allows the ratchet pawl of the ratchet member to reliably engage with or disengage from the engagement member of the cam when the rope reel is rotated in the engine starting direction or in the opposite direction, resulting in a stable operation being performed. 
   Moreover, in one embodiment of the present invention, the ratchet mechanism comprises the ratchet member swingably supported on the side surface of the outer peripheral portion of the rope reel, and the ratchet member is biased by the biasing means so as to come into contact with and slide on the inner circumferential surface of the outer wall of the casing. Such construction allows the ratchet pawl of the ratchet member to reliably engage with or disengage from the engagement member of the cam in a stable manner depending on the rotational direction of the rope reel as in the aforementioned embodiment. 
   Additionally, in one embodiment of the present invention, the ratchet mechanism comprises the ratchet member pivotally supported on the side surface of the rope reel and provided at one end thereof with the ratchet pawl engageable with the engagement member formed on the outer periphery of the cam and the biasing spring piece having a curved shape and supported at the opposites ends thereof on the ratchet member while the curved portion of the biasing spring piece is kept in sliding contact with the inner circumferential surface of the outer wall of the casing, so that the biasing spring piece is deformed due to the sliding resistance between the curved portion and the inner circumferential surface, whereby the opposite ends of the biasing spring piece pivotally rotate the ratchet member about the pivot. Such construction allows the ratchet pawl of the ratchet member to reliably engage with or disengage from the engagement member of the cam in a stable manner depending on the rotational direction of the rope reel as in the embodiments mentioned above. 
   While illustrative and presently preferred embodiments of the present invention have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.