JPH0138304Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a recoil starting device for a manually started engine.

Small engines, such as general-purpose engines, are equipped with a recoil starter that uses a rope to start the engine. The outline of this device is that it usually includes a rotary drive plate around which a rope is wound, and a rotary driven plate arranged coaxially with the drive plate and connected to the engine side, for example, the crankshaft.When starting, the rope is pulled and the drive plate Rotate the
A locking pawl pivotally attached to this driving plate locks the driven plate and rotates it together. On the other hand, after startup, the locking pawl and driven plate are unlatched and only the driven plate rotates. The engine is started in this manner.

Incidentally, in recent years, in this type of recoil starting device, in order to reduce the weight and cost of the device, models in which the drive plate or locking pawl is made of synthetic resin have been put into practical use, but in general, they are made of metal. The disadvantage is that the strength is lower than that of . In particular, regarding the locking pawl and its pivoting portion on the drive plate, where force is applied, the locking pawl is subject to bending stress due to component forces generated due to misalignment between the engaging portion of the pawl and the driven plate and the pivoting portion. In addition, all of the engine driving force acts on the pivoting portion of the locking pawl on the drive plate. Conventionally, it has been proposed that the side of the locking pawl in contact with the driven plate is brought into contact with the drive plate in order to compensate for the drawback of bending stress on the locking pawl due to component force, but such a method also A shearing force is applied to the pawl, and a bending stress is applied to the pivot joint.

The object of the present invention is to provide an engine recoil starting device that effectively reduces the stress acting on the locking pawl and the pivoting portion between the drive plate and the locking pawl, and greatly improves durability. be.

In order to achieve such an objective, the present invention includes a rotary drive plate, a rotary driven plate disposed coaxially with the drive plate and connected to the engine side, and a rotary driven plate that is pivotally attached to the drive plate and locks with the driven plate at the time of starting. The application is applied to a recoil starting device equipped with a locking pawl that locks (1) and releases the lock after startup, and its main structure is that the locking pawl and the drive plate lock in tandem (1) at the time of startup. a locking portion for a second locking) is provided, a locking surface of the first locking and a locking surface of the second locking are formed substantially parallel, and a locking surface of the first locking and a locking surface of the second locking are formed in a direction orthogonal to The locking surface is characterized in that the two locking surfaces are arranged so that at least a portion thereof overlaps in the direction of the arrow, and that the overlapping portion is offset from the pivot axis of the locking pawl.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

In the drawings, FIG. 1 is a cross-sectional side view taken along line 1-1 in FIG. 2 of the recoil starting device according to the present invention, FIG. 2 is a sectional view taken along line 2-2 in FIG. 3- in Figure 2
FIG. 4 is a main part configuration diagram showing a three-line cross section, and FIG. 4 is an explanatory diagram of the function of the locking pawl.

First, in order to clarify the present invention, Figures 1 and 2 are shown.
A schematic configuration of the recoil starting device will be described with reference to the drawings.

In the figure, reference numeral 1 indicates a recoil starter, 2 a starter case, and a fixed shaft 3 is fixedly installed in the center of the starter case. A disc-shaped rotary drive plate 4 is rotatably supported on the fixed shaft 3, and the outer periphery of the drive plate 4 is formed with a rope winding groove 4a having a U-shaped cross section. The end is fixed in a predetermined position in the groove 4a, a starter grip 5 is attached to the outer end, and the rope 6 pulled out to the outside of the case 2 is wound. A return spring 7 for biasing the rope 6 in the direction of rewinding the drive plate 4 and a rope cover 8 surrounding the circumference of the rotary drive plate 4 are attached to the case 2 side of the drive plate 4.

On the other hand, on the engine side (opposite side to the case 2 side) of the drive plate 4, near the fixed shaft 3, one end of a locking pawl 10 is rotatably supported by a ratchet shaft 9. . The locking pawl 10 has a bow shape and is made of, for example, a sintered metal, and has a predetermined thickness in consideration of strength. The tip forms a locking surface 11 that locks with the rotating driven plate side, which will be described later, and this locking surface 11 is further tilted slightly backward in the radial direction (in the opposite direction to the rotational direction). 11a and a substantially perpendicular locking surface 11b. Note that this locking pawl 10 is a spring 12 whose one end is fixed 12a to the drive plate 4.
(See Fig. 2) is biased in the direction of the fixed shaft 3.

Further, a wave washer 13 is attached to the fixed shaft 3.
A substantially elliptical cam plate 14 is supported with its center biased to one side through the cam plate 14, and this cam plate 14 is frictionally fixed by a predetermined friction force generated by the action of the wave washer 13 until a certain rotational force is reached, and is held in place beyond that. The cam plate 14a can be rotated about the fixed shaft 3 by the force of , and the cam plate 14a, which is the half circumference on the longer diameter side, comes into contact with the inner end of the locking pawl 10. Note that 19 is a thrust washer.

On the other hand, 15 is a rotary driven plate arranged coaxially with the drive plate 4, and in particular, the cam plate 14 and the locking pawl 10.
is formed as a rotatable member on the outside thereof, and the locking pawl 1 is provided on the inner diameter portion 15a of the member.
A plurality of recesses 16 are provided at predetermined intervals to which the locking surfaces 11 of 0 are locked. In particular, the locking surface 1 on the claw 10 side
Locking surfaces 16a and 16b are formed in surface contact with 1a and 11b, respectively, and the locking surfaces 11a and 16
The lock a is configured as a first lock. In addition,
The driven plate 15 is connected to an engine (not shown), that is, one end of a crankshaft, so that the rotation of the driven plate 15 can be transmitted to the crankshaft.

Therefore, even with the above configuration, recoil starting can be performed in principle.

Next, the main structure of the present invention will be explained with reference to FIGS. 2 and 3.

First, on the tip side of the locking claw 10, the drive plate 4 is
A locking protrusion 17 is formed protrudingly on the side surface. As shown in FIG. 2, the locking protrusion 17 has a substantially triangular shape in the front direction, and one side of the inner side of the locking protrusion 17 coincides with the inner side of the locking pawl 10, that is, the side on the fixed shaft 3 side. Furthermore, as shown in FIG.
It is formed into a triangular pyramid with the apex on the tip side of 0. In particular, the bottom surface of this triangular pyramid has a locking surface 17 according to the present invention.
a, which is substantially parallel to the locking surface 11a of the locking pawl 10.

On the other hand, on the drive plate 4 side, as shown in FIG. 3, a locking recess 18 is formed in which the locking protrusion 17 can be accommodated.
The protrusion 17 is movable within the recess 18, and when the locking pawl 10 locks in the recess 16 of the driven plate 15 at the time of starting as shown in FIG. An inner wall is provided which locks in surface contact with the locking surface 17a of the locking surface 17a.
8a, which lock is configured as a second lock according to the invention.

Further, the above-mentioned locking surfaces 11a and 16a are formed so as to be included in the vertical line R passing through the locking surfaces 17a and 18a that lock with each other, that is, when viewed from the direction of the vertical line R, the locking surfaces 11a and 16a, Locking surface 17a
and 18a are at least partially polymerized,
As shown in FIG. 4, an overlapping surface S is provided, and the larger the overlapping surface S is, the more compressive stress there will be on the nail, which is desirable from the viewpoint of the strength of the nail.

Therefore, when focusing on the main parts of the present invention described above, the parts that the locking claw 10 locks at the time of startup are the locking surfaces 11a and 11b provided at the tip of the locking claw 10,
In addition, the stress F is the locking surface 17a of the locking protrusion 17, and as shown in FIG.
A compressive stress F ₁ acts on the latching surface 11b, and a component force F ₂ acts on the locking surface 11b, and as a result, the stress applied to the latch shaft 9, that is, the pivoting portion of the locking pawl 10, is significantly reduced. Note that the circle in FIG. 4 indicates the center of the fixed shaft 3.

Next, the operation of the starting device 1 will be explained.

First, the rope 6 is wound around the rope winding groove 4a by the biasing action of the return spring 7. If the rope 6 is pulled out manually, the drive plate 4 is rotated and the locking pawl 10 is moved to the cam surface 14a.
The locking surfaces 11a, 11b and 16a, 16b, and the locking surfaces 17a and 18a lock onto the locking surfaces 11a, 11b and 16a, 16b, and by further pulling out the rope 6, the locked state is achieved. Mama cam board 1
4 (overcoming the frictional contact force of the cam plate 14), the driving plate 4 rotates, causing the driven plate 15 and further the crankshaft to rotate, thereby starting the engine.

When the engine starts, the driven plate 15 rotates, and at this time, the locking pawl 10 is connected to the cam plate 1 by the rising portion 16c on the rear side of the recess 16 of the driven plate 4.
If the rotation of the drive plate 4 is stopped and the drive plate 4 is rotated in the opposite direction by unwinding the rope 6, the force of the spring 12 is applied. The locking pawl 10 is pushed inward along the cam plate 14. Therefore, the locking between the locking pawl 10 and the driven plate 15 side is released. In addition, at this time, cam plate 1
The short diameter portion 14b of the locking pawl 10 is rotated by contacting the inner side of the locking pawl 10 on the pivoting portion side, and the cam surface 14a is rotated.
It is set to the initial position in contact with the inner end of 0.

Incidentally, in the above-mentioned embodiments, arbitrary changes such as the shape and quantity of the locking pawls 10, and other detailed shapes and configurations may be made within the scope of the present invention without departing from the gist of the invention.

As is clear from the above description, the engine recoil starting device according to the present invention has a locking pawl provided on the drive plate and a driven plate side that the locking pawl locks (first locking). The second
In addition, since the locking surface of the first lock and the locking surface of the second lock are substantially parallel, the stress acting on the pivoting portion of the locking pawl is effectively reduced. It is possible to significantly improve the durability of the locking pawl and the life of the recoil starting device, which is especially useful when each part is molded from synthetic resin to reduce cost and weight. It can be provided as a recoil starting device. Also, the above 2
Since the two locking surfaces are offset from the pivot, the force applied to the pivot among the compressive stress applied to the locking pawl is small, and sufficient durability is achieved without increasing the strength of the pivot portion of the locking pawl. can be maintained.

[Brief explanation of drawings]

Figure 1 shows the second part of the recoil starting device according to the present invention.
1-1 line sectional side view in the figure, Figure 2 is a 2-1 line cross-sectional view in Figure 1.
FIG. 3 is a main part configuration diagram showing a cross section taken along line 3--3 in FIG. 2, and FIG. 4 is an explanatory diagram of the function of the locking pawl. In the drawing, 4 is a rotary drive plate, 10 is a locking claw, 1
1a, 11b, 16a, 16b, 17a, 18a
is a locking surface, 15 is a rotating driven plate, R is a vertical line, and S is a superposition surface.

Claims (1)

[Scope of utility model registration request] a rotary drive plate, a rotary driven plate disposed coaxially with the drive plate and connected to the engine side, pivoted to the drive plate and locked with the driven plate at the time of startup (first locking);
In a recoil starting device including a locking pawl that is released from the locking at the time of starting, a locking portion is provided in which the locking pawl and the drive plate are mutually locked (second locking) at the time of starting, and the first A locking surface of the lock and a locking surface of the second lock are formed substantially parallel to each other, and at least a portion of the two locking surfaces overlap when viewed in a direction perpendicular to the two locking surfaces. A recoil starting device for an engine, characterized in that the overlapping portion is deviated from the axis of the locking pawl.