Internal-combustion engines – Starting device – Mechanical
Utility Patent
1997-12-11
2001-01-02
Dolinar, Andrew M. (Department: 3747)
Internal-combustion engines
Starting device
Mechanical
C074S00700R, C192S042000
Utility Patent
active
06167858
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns a pulley for a recoil starter, more particularly those which provide a dog which is capable of moving towards the engine side along an axis at a time for starting operation, and a touching nail, which is attached to a crank shaft opposing thereto, and is capable of contacting with said dog (hereinafter simply referred to as crank pulley).
2. Description of the Related Art
In Japanese Patent Application No. Hei 8-94470 (Japanese Patent Application Kokai No. Hei 9-105371), a recoil starter is disclosed, in which a reel which may be revolved by pulling a rope, and a dog made of synthetic resin, which is capable of moving to axial direction by revolving said reel, are provided, and by moving said dog to a protrusion on a fly wheel, or the crank pulley side made of alloy die-cast, thereby contacting a contact face on the dog to a protrusion on a fly wheel, or a touching nail provided on the crank pulley, to start rotating thereof.
In the recoil starter having a constitution, as disclosed above, it is required to use a crank pulley of die casting alloy, when no protrusion is provided on the fly wheel, however, said crank pulley must become expensive. Since the crank pulley may be obtained economically, provided that the crank pulley may be made by press forming, it is required to modify a shape of the crank pulley into those which are capable of being easily formed by press forming.
Various shapes, which are capable of press forming, may be considered, and the most simple way is, for example, shown in
FIG. 7
, wherein a touching nail
18
is formed by cutting a partial end of the crank pulley
19
, to bend the notched part along parallel to an axis thereof thereby forming an extrusion. In this case, a contact face
5
of the dog
4
in the recoil starter
1
, and a contact face
18
of the touching nail are not firmly attached to each other all over the faces, due to an error during forming parts, clearances between assembled parts, and the like, resulting in causing a slight slant (&thgr;). Accordingly, both contacting parts are liable of sliding to cause unstable contact.
Furthermore, in the crank pulley of such a recoil starter, a distance between the crank pulley
19
and dog
4
of the recoil starter
1
becomes larger at a certain frequency to cause unacceptable and unstable contact, as shown in FIG.
2
. Under such a state, since remarkably strong power may be applied between both parts, a contact with a touching nail
12
is liable to be released, as shown by the dotted line in FIG.
2
. At that time, a top part
7
of the dog
4
is damaged by the touching nail
12
.
Besides these, in the recoil starter of this type, soon after the engine being started, revolution of the pulley
10
becomes faster than that of the dog
4
. Accordingly, a relative revolving direction between the crank pulley
10
and the dog
4
comes to reversal, regardless of concurrent revolving on starting the engine, thereby accidentally hitting the touching nail
12
onto a back face
6
of the dog
4
, resulting in proceeding movement relatively towards arrow A direction. At this collision, the dog
4
may be damaged.
These problems may be similarly caused not only on starting the engine, but also by erroneously pulling the starting rope during running the engine, or by moving the dog to the crank pulley side due to abnormal vibration, and the like.
The present invention has an object for providing a novel crank pulley for recoil starter for overcoming several problems, discussed above, at once.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a crank pulley comprising a recoil starter providing dog which is capable of moving towards an engine side along an axial direction during a starting operation, and a touching nail which provided on a crank axis of engine opposite thereof, and is capable of engaging with said dog, wherein said touching nail is integrally formed with the crank pulley by press forming in a shape of protrusion towards the recoil starter side, and a top of said touching nail is bent towards the recoil starter side in L shape, a top face of which is formed as attaching face with said dog, and a corner of a top attaching part of the touching nail at the recoil starter side is formed into either curve or chamfer face, and outer corner part in bent part of the touching nail is formed into either curved or chamfered face.
Preferably, a rib is formed between the touching nail and the flange in the crank pulley. More preferably, the touching nail may be protruded by slanting towards a direction opposite to the revolving direction of the crank pulley.
Both corner parts in the radius direction of the contacting face in the touching nail may be shaped in a curve or chamfer face.
The crank pulley for recoil starter according to the present invention may be supplied with a cheaper price by applying a press forming process. Besides this, since a thickness of the contact part of the crank pulley with a contacting face of the dog is as thin as of a thickness of raw steel material in radial direction, there is no trouble in unstable contact, even if a slight slant may be caused between a contact face of the dog and that of the crank pulley due to an error in production of parts, or clearance in the assembled product.
REFERENCES:
patent: 2374685 (1945-05-01), Kissel et al.
patent: 2709994 (1955-06-01), Chandler
patent: 4638775 (1987-01-01), Lindström
Armstrong, Westerman Hattori, McLeland & Naughton
Dolinar Andrew M.
Showakiki Industry Co., Ltd.
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