Patent Publication Number: US-6981482-B2

Title: Recoil starter

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a recoil starter having a recoil rope wound around a rope reel, wherein one end of the recoil rope drawn outside a casing of the recoil starter is pulled to rotate the rope reel so that a rotational force of the rope reel is transmitted to a cam via a damper spring, and then a rotation of the cam is transmitted to a rotational member coupled to a crankshaft of an engine via a ratchet mechanism to rotate the rotational member, whereby the engine is started. 
   2. Description of the Related Art 
   Among recoil starters designed to transmit a rotation of a rope reel, rotated by pulling a recoil rope, to a cam and further rotate a rotational member such as flywheel magnet or drive pulley via a centrifugal clutch or other ratchet mechanism which engages with or disengages from the cam, a recoil starter has been proposed which is constructed to absorb a shock, caused due to fluctuations in load during engine startup and transmitted to an operator&#39;s hand, by resiliently coupling the rope reel and the cam through a damper spring in the form of a coil spring to transmit a rotation of the rope reel to the cam via the damper spring. 
   In the proposed recoil starter, as shown in  FIG. 8 , a damper spring  34  is received within annular recesses  32  and  33  which are formed on opposing surfaces of a rope reel  30  and a cam  31  while one end portion  35  thereof bent in U shape is fitted within a holding groove  36  formed on the rope reel  30  and the other end portion  37  thereof, bent in an axial direction, is inserted into an opening  38  formed in the cam  31 , so that the rope reel  30  and the cam  31  are rotationally coupled to each other via the damper spring  34 . When a rope  39  wound around the rope reel  30  is pulled to rotate the rope reel  30 , the cam  31  is rotated via the damper spring  34 . As a result, engagement of cam pawls  40  formed on the outer peripheral surface of the cam  31  with a ratchet  42  provided on a rotational member  41  attached to a crankshaft of an engine allows a rotation of the cam  31  to be transmitted to the rotational member  41 , whereby the crankshaft coupled to the rotational member  41  is rotated. When the rotation of the cam  31  is precluded by a startup resistance of the engine, the damper spring  34  is twisted, so that a shock on the rope reel  30  is cushioned and a rotational force of the rope reel  30  is stored in the damper spring  34 . When a driving force of the rope reel  30  exceeds the startup resistance of the engine, the rotational force stored in the damper spring  34  is released, so that the rotational member  41  is rotated via the cam  31  to start the engine (e.g., Japanese Patent Application No. 2002-144695). 
   In the proposed recoil starter, the opposite end portions  35  and  37  of the damper spring  34  are held on the rope reel  30  and the cam  31  in a fixed manner, respectively. Thus, the end portions  35  and  37  of the damper spring  34  cannot radially move. Therefore, although a middle part of a coiled portion of the damper spring  34  winds and tightens around the outer peripheral surfaces of bosses  43  and  44  of the rope reel  30  and the cam  31 , opposite ends of the coiled portion are deformed to the extent that the ends are detached from the outer peripheral surfaces of the bosses  43  and  44  as shown in  FIG. 8 . Under such a condition, the bent portions at the opposite ends of the damper spring  34  undergo an excessive stress, possibly resulting in breakage of the damper spring  34 . 
   A technique has been proposed which restricts the relative rotational angle between the rope reel  30  and the cam  31  by stopper means arranged between the rope reel  30  and the cam  31  to keep load on the damper spring  34  below a predetermined setting. In this technique, however, when the stopper means operates, a feel of collision is caused and transmitted as a shock to the operator&#39;s hand pulling the recoil rope  39 , resulting in an unpleasant feel during startup. Further, since the cam  31  is simply supported at its central portion by a shaft  46  formed on a casing  45  so as to be rotatable, when a spring force of the damper spring  34  acts on the cam  31  while only one of the ratchets  42  is engaged with the cam pawl  40 , an eccentric load or a strong leaning force acts on the cam  31 , possibly resulting in breakage of the cam  31 . 
   Further, it is desirable that the damper spring  34  have greater shock-absorbing and force-storing capabilities. While these capabilities can be enhanced by increasing a wire diameter and a winding diameter of the damper spring  34 , the sizes of the annular recesses  32  and  33  receiving the damper spring  34  must be increased in outer diameter thereof corresponding to the increase of the wire diameter and winding diameter of the damper spring  34 . In the proposed technique, the cam pawls  40  are formed such that the cam pawls  40  protrude outwardly from the outer surface of an outer peripheral wall  47  of the annular recess  33  formed on the cam  31  to receive therein the damper spring  34 , as shown in  FIGS. 9A and 9B . Therefore, the outer size of the cam  31  is restricted in relation to such parts as the ratchet  42 , a cooling fan formed on the rotational member  41 , the casing  45  and the like. Consequently, since the size of the annular recess  33  is thus restricted, it is difficult to increase the wire diameter and winding diameter of the damper spring  34  unless the overall size of the recoil starter is scaled up. 
   SUMMARY OF THE INVENTION 
   The present invention has been made in order to solve the problems associated with the related techniques. 
   It is therefore an object of the present invention to provide a recoil starter having enhanced durability by improving durability of a damper spring incorporated therein through inhibiting excessive deformation of the damper spring. 
   It is another object of the present invention to provide a recoil starter capable of receiving a damper spring with high shock-absorbing and force-storing capabilities without scaling up the overall outer dimensions thereof. 
   It is a further object of the present invention to provide a recoil starter having enhanced durability by improving durability of a cam incorporated therein through inhibiting an eccentric load on the cam. 
   In accordance with an aspect of the present invention, there is provided a recoil starter. The recoil starter comprises: a casing having a reel shaft formed on an inside thereof; a rope reel rotatably mounted to the reel shaft and having a recoil rope wound therearound; a spiral spring for rotationally urging the rope reel in a direction of winding the recoil rope; a cam rotatably mounted to the reel shaft in a manner to face the rope reel; a rotational member attached to a crankshaft of an engine and provided with a ratchet mechanism which disengageably engages with the cam; and a damper spring in the form of a coil spring disposed around outer peripheries of bosses which are formed on the rope reel and the cam, respectively, the damper spring having opposite ends held respectively on the rope reel and the cam, wherein a rotational force of the rope reel is transmitted to the cam via a resilience of the damper spring and a rotation of the cam is then transmitted to the rotational member via the ratchet mechanism to thereby start the engine, wherein the opposite ends of the damper spring are provided with respective engaging portions which are radially movably supported by holding portions on the rope reel and the cam, respectively, so that when the damper spring is resiliently deformed by a startup resistance of the engine, substantially the overall length of a coiled portion of the damper spring winds and tightens uniformly around the outer peripheral surfaces of both of the bosses formed on the rope reel and the cam, respectively. 
   In a preferred embodiment of the present invention, the bosses are extended from and integrally formed on the rope reel and the cam, respectively, and include respective end faces which are butted against each other substantially at the middle of the coiled portion of the damper spring. 
   In a preferred embodiment of the present invention, the cam is rotatably supported at two locations, one of the locations being a center support portion defined by an end face of the reel shaft and the other being an outer peripheral support portion defined by an outer peripheral surface of a flange portion which is radially outwardly protruded and integrally formed on the cam so as to engage with the side surface of the rope reel. 
   In a preferred embodiment of the present invention, the rope reel and the cam are provided on joining surfaces thereof with respective annular recesses which are formed to face each other so as to receive the damper spring therein, the rope reel and the cam being coupled together via the damper spring; and the cam includes an outer peripheral wall which forms the annular recess thereof and on which a plurality of openings are formed circumferentially apart so that portions of the outer peripheral wall between the adjacent openings each define a cam pawl which is engageable with the ratchet mechanism. 
   In a preferred embodiment of the present invention, the outer peripheral wall of the cam forming the annular recess thereof is provided on one side thereof with a flange portion which is radially outwardly extended and integrally formed on the outer peripheral wall, and wherein each of the cam pawls has opposite ends thereof connected to and supported by an inner peripheral rim of the flange portion and a bottom of the annular recess of the cam, respectively. 
   In accordance with another aspect of the present invention, there is provided a recoil starter which comprises: a casing having a reel shaft formed on an inside thereof; a rope reel rotatably mounted to the reel shaft and having a recoil rope wound therearound; a spiral spring for rotationally urging the rope reel in a direction of winding the recoil rope; a cam rotatably mounted to the reel shaft in a manner to face the rope reel; a rotational member attached to a crankshaft of an engine and provided with a ratchet mechanism which disengageably engages with the cam; and a damper spring interposed between the rope reel and the cam, wherein a rotational force of the rope reel is transmitted to the cam via a resilience of the damper spring and a rotation of the cam is then transmitted to the rotational member via the ratchet mechanism to thereby start the engine, wherein the rope reel and the cam are provided on joining surfaces thereof with respective annular recesses which are formed to face each other so as to receive the damper spring therein, the damper spring having opposite ends thereof held respectively onto the rope reel and the cam so that the rope reel and the cam are coupled together via the damper spring; and the cam includes an outer peripheral wall which forms the annular recess thereof and on which a plurality of openings are formed circumferentially apart so that portions of the outer peripheral wall between the adjacent openings each define a cam pawl which is engageable with the ratchet mechanism. 

   
     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 front view illustrating a recoil starter according to an embodiment of the present invention; 
       FIG. 2  is a front view illustrating the recoil starter shown in  FIG. 1  with a rotational member removed; 
       FIG. 3  is a sectional side elevation view of the recoil starter shown in  FIG. 1 ; 
       FIG. 4  is an exploded perspective view showing a rope reel, a damper spring and a cam used in the embodiment of  FIG. 1 ; 
       FIG. 5  is a sectional side elevation view of the cam shown in  FIG. 4  which has the damper spring received therein; 
       FIG. 6  is a sectional view taken along line  6 — 6  of  FIG. 5 ; 
       FIG. 7  is a sectional side elevation view of the recoil starter shown in  FIG. 3  wherein the damper spring is tightly wound; 
       FIG. 8  is a sectional side elevation view illustrating a recoil starter in the related art in a state where a damper spring is subjected to an excessive stress; and 
       FIG. 9A  is a perspective view illustrating a cam employed in the recoil starter shown in  FIG. 8  and  FIG. 9B  is a longitudinal sectional side view of the cam which has the damper spring received therein. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A preferred embodiment of the present invention will now be described with reference to the drawings. A recoil starter according to the embodiment of the present invention, as shown in  FIG. 1 , is constructed such that when a handle  3  which is joined to one end of a recoil rope  2  exposed outside a casing  1  is pulled, a rope reel  4  received within the casing  1  is rotationally driven and thus a cam  8  is rotated by the rope reel  4 , so that a rotational member  9  coupled to a crankshaft of an engine via a ratchet mechanism  10  which is engageable with cam pawls  11  formed on an outer peripheral surface of the cam  8 , to thereby start the engine. 
   As shown in  FIGS. 2 and 3 , the rope reel  4  has the recoil rope  2  wound therearound, of which the one end is drawn outside the casing  1 , and is rotatably supported by a reel shaft  5  which is integrally formed on an inside of the casing  1  in a manner to be protruded inwardly in the casing  1 . The other end of the recoil rope  2  wound around the rope reel  4  is fixed to the rope reel  4 . The one end of the recoil rope  2  is drawn outside the casing  1  and has the handle  3  joined to the extremity thereof to manually pull the recoil rope  2 . Pulling the handle  3  unwinds a wound portion of the recoil rope  2  from the rope reel  4  to rotate the rope reel  4  about the reel shaft  5 . 
   A recoil spiral spring  6  is provided between a side surface of the rope reel  4  and an inner wall surface of the casing  1  so as to rotate the rope reel  4 , which has been rotated by pulling of the recoil rope  2 , in reverse, to thereby rewind the recoil rope  2  onto the rope reel  4 . One end at an inner peripheral side of the recoil spiral spring  6  is fixed to the casing  1  while the other end at an outer peripheral side thereof is fixed to the rope reel  4 . As the rope reel  4  is rotated by pulling the recoil rope  2 , a rotational force is stored in the recoil spiral spring  6 . When the recoil rope  2  is released, the rotational force stored in the recoil spiral spring  6  rotates the rope reel  4  in reverse, resulting in the recoil rope  2  being wound onto the rope reel  4 . 
   The cam  8  is mounted, adjacently to the rope reel  4 , by a screw  22 , to an end face of the reel shaft  5  formed on the casing  1  so as to be rotatable, so that the cam  8  transmits a rotation of the rope reel  4  to the crankshaft of the engine. A plurality of the cam pawls  11  are formed on the outer periphery of the cam  8  so that the cam pawls  11  are disengageably engaged with the ratchet mechanism  10  provided on the rotational member  9  which is coupled to the crankshaft of the engine. When one of the cam pawls  11  is engaged with the ratchet mechanism  10  of the rotational member  9 , a rotation of the cam  8  is transmitted to the crankshaft of the engine via the rotational member  9 . In the illustrated embodiment, the ratchet mechanism  10  is constructed as a centrifugal clutch, so that due to a rotation of the rotational member  9  after startup of the engine, the ratchet mechanism  10  is rotationally moved in a direction of disengaging from the cam pawls  11  by a centrifugal force. As a result, transmission of rotation between the engine side and the cam  8  is interrupted, to thereby prevent transmission of rotation from the engine side to the recoil starter side. 
   Annular recesses  12  and  13  are formed respectively on opposing side surfaces of the rope reel  4  and the cam  8  such that the annular recesses  12  and  13  are opposite to each other. The annular recesses  12  and  13  receive a damper spring  14  therein which rotationally couples the rope reel  4  and the cam  8 . As shown in  FIG. 4 , the damper spring  14  is configured in the form of a torsion coil spring, and has an engaging portion  15  at one end thereof, which engaging portion is formed by bending one end portion of the damper spring  14  horizontally into a U shape. The engaging portion  15  is received within one of holding grooves  16  which are formed on the outside of the annular recess  12  of the rope reel  4  to be contiguous to the annular recess  12 , with a result that the rope reel  4  and the annular recess  12  are rotationally coupled together. Another engaging portion  17 , bent in an axial direction, is formed on the other end of the damper spring  14 . The engaging portion  17  is inserted in a holding hole  18  which penetrates from a bottom  28  of the annular recess  13  to a top side of the cam  8 , so that the other end of the damper spring  14  is rotationally coupled to the cam  8 . 
   The annular recesses  12  and  13  of the rope reel  4  and the cam  8  include respective inner peripheral surfaces which form bosses  19  and  20  having the same outer diameter. The damper spring  14  is disposed such that end faces of the bosses  19  and  20  are butted against each other substantially at the middle of the coiled portion of the damper spring  14  received within the annular recesses  12  and  13 . Such construction allows the coiled portion of the damper spring  14  to wind and tighten substantially uniformly around outer peripheral surfaces of the respective bosses  19  and  20  of the rope reel  4  and the cam  8  when a predetermined rotational force is stored in the damper spring  14  by a startup resistance of the engine, with a result that a further elastic deformation of the damper spring  14  is inhibited and a maximum stress is limited. 
   As shown in  FIGS. 3 and 4 , the engaging portion  15  of the damper spring  14  held by the rope reel  4  is received within the holding groove  16  and held such that the engaging portion  15  can move toward and away from the outer peripheral surface of the boss  19  of the annular recess  12  of the rope reel  4 . The holding hole  18  formed at the bottom  28  of the annular recess  13  of the cam  8  is formed to be elongated in a radial direction of the cam  8 . The engaging portion  17  at the other end of the damper spring  14  is loosely fitted into the holding hole  18  so as to allow the engaging portion  17  to approach the outer peripheral surface of the boss  20  of the cam  8 . Such construction allows the overall length of the coiled portion of the damper spring  14  to uniformly wind and tighten around the bosses  19  and  20  as shown in  FIG. 7  when the coiled portion of the damper spring  14  winds and tightens around the bosses  19  and  20 . Such function is the same as that of a mechanism of a publicly known spring clutch. The coiled portion of the damper spring  14  functions as a spring clutch as the coiled portion winds and tightens around the bosses  19  and  20  of the rope reel  4  and the cam  8 , resulting in the bosses  19  and  20  being rotationally coupled together. 
   As shown in  FIGS. 4 to 6 , the outer peripheral wall  26  of the cam  8  which forms the annular recess  13  is provided with a flange portion  23  which is radially outwardly extended and integrally formed on one side of the outer peripheral wall  26 . A plurality of openings  27  are formed circumferentially apart from one another by removing portions of the outer peripheral wall  26  of the cam  8  at a plurality of locations such that the openings  27  penetrate from the inside of the annular recess  13  to the outside of the outer peripheral wall  26 . The un-removed portions of the outer peripheral wall  26  between the adjacent openings  27  form the respective cam pawls  11  which are distributed in a circumferential direction. The outer peripheral wall  26  forming the cam pawls  11  have opposite ends connected by an inner peripheral rim of the flange portion  23  and the bottom  28  of the annular recess  13 . This allows the damper spring  14  to be received within and supported by the inner peripheral surfaces of the cam pawls  11  and allows engagement surfaces  29  of the cam pawls  11  facing in the circumferential direction to engage with the ratchet mechanism  10 , whereby the rotation of the cam  8  is transmitted to the rotational member  9  via the ratchet mechanism  10 . 
   Further, the engagement surfaces  29  engageable with the ratchet mechanism  10  are formed on opposite circumferential ends of each of the cam pawls  11  of the cam  8  in a manner to extend in a direction perpendicular to the circumferential direction, as shown in  FIGS. 5 and 6 . In addition, the holding grooves  16 , which are formed in association with the annular recess  12  of the rope reel  4  so as to fit therein the engaging portion  15  of the damper spring  14  received in the annular recess  12 , are formed symmetrically in the circumferential direction as shown in  FIG. 4  such that the holding grooves  16  allow either of damper springs with different winding directions to be fitted therein, resulting in the recoil starter being applicable to both of an engine running in a certain rotational direction and an engine running in an opposite rotational direction. 
   In addition, the flange portion  23  of the cam  8  is provided at an outer peripheral side of the side surface thereof with an annular guide  24  which is integrally formed on the flange portion  23  so as to protrude toward the rope reel  4 , as shown in  FIG. 4 . The circular guide  24  is fitted within an annular recessed portion  25  which is formed on the side surface of the rope reel  4  so as to guide relative rotation between the cam  8  and the rope reel  4 . The cam  8  and the rope reel  4  are incorporated into the casing  1  in the following manner. First, the rope reel  4  is mounted to the reel shaft  5  formed on the casing  1 . Then, the damper spring  14  is attached to the boss  19  of the rope reel  4  while the engaging portion  15  of one end of the damper spring  14  is fitted within the holding groove  16  of the rope reel  4 . Thereafter, the cam  8  is placed on the side surface of the rope reel  4  such that the engaging portion  17  at the other end of the damper spring  14  is inserted into the holding hole  18  formed on the cam  8 , and then the screw  22  is fastened to the distal end of the reel shaft  5 . 
   The cam  8  is supported at its center by a proximal portion of the screw  22  so as to be rotatable with respect to the reel shaft  5  and also supported at the annular guide  24  on the outer peripheral side of the flange portion  23  by the annular recessed portion  25  of the rope reel  4  so as to be rotatable, so that inclination of the cam  8  due to an eccentric load acting on the cam  8  can be inhibited and breakage of the cam  8  due to the eccentric load can be prevented. In the illustrated embodiment, the annular guide  24  is formed on the flange portion  23  of the cam  8 . However, the same effect can be obtained by forming an annular guide such that the guide protrudes from the rope reel  4  toward the cam  8  and by engaging an outer peripheral edge of the flange portion  23  of the cam  8  with an inner peripheral surface of the annular guide of the rope reel  4 . 
   Now, the operation of the recoil starter of the embodiment will be described. Prior to engine startup operations, the ratchet mechanism  10 , provided on the rotational member  9  which is coupled to the crankshaft of the engine, is retracted due to the action of a spring (not shown) and is located at an inner side position where the ratchet mechanism  10  is to come into contact with the cam pawls  11  formed on the cam  8 . When the recoil rope  2  is pulled to rotate the rope reel  4 , the cam  8  is caused to rotate together with the rope reel  4  via the damper spring  14 . The cam pawl  11  of the cam  8  is brought into contact with the ratchet mechanism  10 , to thereby rotate the rotational member  9  via the ratchet mechanism  10  and also rotate the crankshaft of the engine coupled to the rotational member  9 . At this time, although a rotational load of the cam  8  increases due to an increase in rotational load resulting from a startup resistance of the engine, the damper spring  14  is twisted to absorb the load, whereby a shock is prevented from being directly transmitted to the recoil rope  2 . 
   At this time, twisting of the damper spring  14  results in a rotational force of the rope reel  4  being stored in the damper spring  14 . As the damper spring  14  is twisted, the diameter of the coiled portion thereof diminishes, so that the coiled portion thereof is caused to wind and tighten around the bosses  19  and  20  of the rope reel  4  and the cam  8 , with the result that no more stress acts on the damper spring  14 . Under this condition, the rope reel  4  and the cam  8  are coupled together as an integral part by the action of the damper spring  14  like a spring clutch, so that a rotation of the rope reel  4  is directly transmitted to the cam  8 . At this time, since the engaging portions  15  and  17  at the opposite ends of the damper spring  14  are moved inwardly, substantially the overall length of the coiled portion of the damper spring  14  comes into a close contact with the outer peripheral surfaces of the bosses  19  and  20 , with the result that the end portions of the damper spring  14  are not subjected to an excessive stress. 
   At this time, an eccentric load acts on the cam  8  between the cam pawl  11  engaged with the ratchet mechanism  10  and the holding hole  18  supporting the damper spring  14 . However, the cam  8  is supported at its center by the screw  22  and supported at the annular guide  24  on the outer peripheral side of the flange portion  23  by the peripheral surface of the annular recessed portion  25  of the rope reel  4 , thus inhibiting inclination and deformation of the cam  8  due to the eccentric load. 
   Further, when the rotational force exceeds the startup resistance of the engine as the rope reel  4  is rotated, the rotational force of the rope reel  4  by pulling the recoil rope  2  and the rotational force stored in the damper spring  14  are released to the cam  8 , so that the rotational force is transmitted to the rotational member  9  via the ratchet mechanism  10 . As a result, the crankshaft of the engine is caused to be rotated abruptly, to thereby start the engine. When the engine starts and the crankshaft rotates, the ratchet mechanism  10  moves rotationally outwardly due to the action of centrifugal force, so that the ratchet mechanism  10  disengages from the cam pawl  11  of the cam  8  to prevent a rotation of the engine from being transmitted to the cam pawls  11 . When the recoil rope  2  is loosened after startup of the engine, the rope reel  4  is rotated in the reverse direction by the rotational force stored in the recoil spiral spring  6 , whereby the recoil rope  2  is wound onto the rope reel  4 . 
   As described above, according to the invention, when an excessive load occurs on the engine side, the damper spring winds and tightens around the outer peripheral surfaces of the bosses formed on the rope reel and the cam, so that substantial deformation of the damper spring due to the excessive load is inhibited. Therefore, a decrease in durability of the damper spring due to the excessive load can be prevented. Moreover, according to the present invention, the coiled portion of the damper spring rotationally couples the rope reel and the cam together as an integral part by gradually winding and tightening around the bosses, thus giving no feel of collision unlike the stopper in the related art described above and providing an improved feel during engine startup operations performed by pulling the recoil rope. 
   Further, since the engaging portions at the opposite ends of the damper spring are supported so as to move toward and away from the outer peripheral surfaces of the bosses, substantially the overall length of the coiled portion of the damper spring winds around the bosses and rotationally couples the rope reel and the cam as an integral part due to the action of the spring clutch. This maintains a stress which is generated at the engaging portions at the opposite ends of the damper spring low, thus extending the durability of the damper spring. 
   In one embodiment of the invention, since the end faces of the bosses formed on the rope reel and the cam are butted substantially at the middle of the coiled portion of the damper spring, the coiled portion of the damper spring winds and tightens uniformly around the outer peripheral surfaces of both of the bosses, thus rotationally coupling the rope reel and the cam together due to the action of the spring clutch. Such construction permits a rotational force from the rope reel to be transmitted to the cam without any excessive stress taking place on the damper spring. 
   In one embodiment of the invention, since the cam is supported at two points, one at the center and the other at the outer periphery, by the screw and the flange portion so as to be rotatable, the cam is more resistant to being inclined and displaced due to an eccentric load. As a result, in a case where only one of the two ratchet mechanisms engages with the cam pawl or in a case where there is provided only one ratchet mechanism, inclination of the cam by a heavy eccentric load can be prevented, thus keeping the cam intact. 
   In one embodiment of the present invention, the outer peripheral wall of the annular recess formed on the cam to receive the damper spring is partially removed to form the openings, so that the un-removed remaining portions of the wall form the cam pawls. Therefore, there is no need to form the cam pawls protruding outwardly from the outer peripheral wall of the cam, so that it is possible to enlarge the outer peripheral wall of the annular recess outwardly by as much as the protruded cam pawls which would otherwise be formed. As a result, it is possible to increase the outer diameter of the annular recess without increasing the outer size of the cam, thus allowing the damper spring with a larger wire diameter and a winding diameter to be received in the annular recess. Therefore, it is possible to accommodate the damper spring having high shock-absorbing and force-storing capabilities without increasing the outer size of the recoil starter, thus providing an easy-to-operate recoil starter. 
   In a case where the damper spring having a size identical to that of the conventional one is used, the outer size of the cam can be reduced, so that the rotational member such as a flywheel magnet, a drive pulley or the like provided on the outside of the cam and the casing containing these parts can be designed to have a reduced size, to thereby provide a compact and lightweight recoil starter. 
   In one embodiment of the invention, the outer peripheral wall of the cam forming the annular recess thereof is provided on one end thereof with the flange portion which is radially outwardly extended and integrally formed on the peripheral wall such that each of the cam pawls has opposite ends thereof connected to and supported by the inner peripheral rim of the flange portion and the bottom of the annular recess, respectively. Such construction can prevent deformation of the cam pawls when the cam pawls are engaged with the ratchet mechanism. 
   While an illustrative and presently preferred embodiment of the present invention has 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.