JPH0210296Y2 - - 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, typically general-purpose engines, are equipped with a recoil starter that uses a rope to start the engine. To give an overview of this device, for example, there is a rotary drive plate with a rope wound around its periphery and whose center is pivotally supported on a fixed shaft, a rotary driven plate arranged coaxially with this drive plate and connected to the engine side, for example the crankshaft, and It consists of a locking pawl pivotally connected to the drive plate and a cam plate pivotally supported by the fixed shaft in frictional contact, and the locking pawl cooperates with the cam plate at the time of starting, that is, when pulling the rope, the above-mentioned When the drive plate is rotated, a locking pawl pivotally attached to the drive plate projects outward and engages the driven plate to rotate them together, and on the other hand, after starting or by returning the rope When the plate is rotated in the return direction, the locking pawl returns inward and sinks into the driving plate, thereby releasing the locking between the locking pawl and the driven plate, so that only the driven plate rotates, and the engine This is what starts the process.

Incidentally, in this type of recoil starting device, a protrusion prevention means is provided to prevent the locking pawl from unnecessarily protruding outward due to vibration or the like after the engine is started.

Conventionally, as shown in FIG. 4, as the protrusion prevention means, a protrusion prevention claw 42 is usually provided on the opposite side of the locking claw 40 from the pivoting portion 41 of the locking claw 40. The protrusion of the locking pawl 40 was prevented by locking it in, for example, an engaging portion provided on the cam plate.

However, the space for installing the locking pawl on the drive plate is extremely limited, and as a result, with the conventional protrusion prevention means described above, the length of the locking pawl has to be shortened. Since the locking angle to the driven plate side is inclined with respect to the force transmission direction, bending stress and shearing force act on the locking pawl 40. Also, when focusing on the transmission of force between the locking pawl 40 and the driven plate, the angle of the tip of the locking pawl 40 is
Since the distance is determined by the distance to the rotation axis of the nail, the shorter the distance, the more inclined it will be with respect to the direction in which the force is applied.As a result, a larger force component will be generated, and bending shear will act on the pawl. That is, as is clear from FIG. 4, when comparing the short locking pawl 40 and the relatively long locking pawl 43, it is too short to obtain the same protrusion distance L for locking with the driven plate. The locking pawl 40 needs to rotate by an angle θ ₁ , while the long locking pawl 43 only needs to rotate by an angle θ ₂ , and since θ ₁ > θ ₂ , the component of the force acting in the direction of arrow B, In other words, the shorter the locking claw is, the greater the bending stress becomes. Therefore, with the conventional protrusion prevention means, the durability of the locking pawl deteriorates. Note that reference numerals 40a and 43a are locking portions with the driven plate.

The present invention eliminates the conventional protrusion prevention claw 42 in order to make the length of the locking claw as long as possible, thereby effectively reducing the effects of bending stress on the locking claw. The object of the present invention is to provide an engine recoil starting device that has improved durability and reliability, and has a sufficient protrusion prevention effect.

In order to achieve such an object, the present invention includes a rotary drive plate pivotally supported on a fixed shaft, a rotary driven plate disposed coaxially with the drive plate, a locking pawl pivotally attached to the drive plate, and A cam plate is equipped with a cam plate supported by frictional contact on a fixed shaft, and the locking pawl cooperates with the cam plate to protrude outward at the time of starting and lock with the driven plate, and also to lock the driven plate after starting or when the driving plate returns. In a recoil starting device that returns inward and sinks into the drive plate by rotation in the direction, one end of the locking pawl is pivotally connected to the drive plate with a pivot, and the other end of the locking pawl is connected to the driven plate. A locking portion is provided at each opposing portion of the cam plate and the locking pawl, so that when the locking pawl is recessed, the locking portions are provided, and when the locking pawl is protruded outward for starting, the locking portions are interlocked. The present invention is characterized in that a locking portion that is released from the locking portion is provided, and the position of the locking portion is between the locking portion of the locking portion pawl and the pivot shaft.

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 the line 1-1 in FIG. 2 of the recoil starting device according to the present invention, FIG. 2 is a view taken along the line 2-2 in FIG. 1, and FIG. 3 is a cam FIG. 4 is a perspective view of the plate and the locking pawl, and an explanatory view 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 disk-shaped rotary drive plate 4 is rotatably supported on the fixed shaft 3, and a rope winding groove 4a having a U-shaped cross section is formed on the outer peripheral edge of the drive plate 4. The inner tip is fixed in a predetermined position in the groove 4a, the starter grip 5 is attached to the outer tip, and the case 2 is closed.
The rope 6 pulled out is wound around the outside. In addition,
A return spring 7 that biases the rope 6 in the direction of rewinding the drive plate 4 and a rope cover 8 that surrounds 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 substantially arcuate shape and is made of, for example, a sintered metal, and has a predetermined thickness in consideration of strength. The tip thereof forms a locking portion 11 that locks with the rotating driven plate side, which will be described later.
This locking portion 11 includes a tip locking portion 11a that is inclined slightly rearward (opposite to the rotational direction) with respect to the radial direction of the drive plate 4, and a side locking portion 1 that is approximately parallel to the circumferential direction.
Consisting of 1b. Note that this locking pawl 10 is a spring 12 (see FIG. 2) whose one end is fixed 12a to the drive plate 4.
The drive plate is biased and pressed inward, that is, toward the center of the drive plate.

Further, a wave washer 13 is attached to the fixed shaft 3.
A substantially inertial circular cam plate 14 is supported with its center biased to one side, 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. With the above force, it becomes possible to rotate about the fixed shaft 3. The cam plate 14 is formed as a cam portion 14a, and the cam surface 1
4b comes into contact with the end side portion of the locking claw 10. Note that 21 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 1.
0 on the inside, and the outside thereof is formed as a rotatable member, and its inner diameter portion 15a is provided with a plurality of recesses 16 at predetermined intervals in which the locking portions 11 of the locking claws 10 lock. The recess 16 is formed with locking portions 16a and 16b that lock with the locking portions 11a and 11b on the locking claw 10 side through surface contact, respectively. 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.

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

First, a latching protrusion 17 is integrally formed on the cam surface 14b of the cam portion 14a closer to the fixed shaft 3 side.
This latching protrusion 17 is formed so that its tip is inclined at a predetermined angle toward the tip of the cam part 14a, and the cam surface 14b is attached to the fixed shaft 3 by the latching protrusion 17.
A locking notch 18 cut out in the lateral direction is formed.

On the other hand, on the inside of the locking claw 10, that is, on the side on the fixed shaft 3 side, there is a locking protrusion 1 formed on the cam surface 14b.
A locking recess 19 for locking 7 is formed in a cutout. This recess 19 is in the opposite direction to the locking notch 18,
That is, it is cut toward the tip of the locking claw 10.

Note that it is desirable that the locking recess of the cam portion 14a be formed as close to the fixed shaft 3 side of the cam portion 14a as possible so as not to generate unnecessary rotational force on the cam portion 14a. The latching recesses 19 should be formed as close to the distal end of the locking pawl 10 as possible so that the latching recess 19 is longer than the distance from the center of gravity of the locking pawl 10 to the pivot point thereof. It is desirable to obtain a sufficient locking force with a small force.

Therefore, the latching protrusion 17 and the latching recess 1
Reference numeral 9 is configured as a latching portion 20 that is latched when the latching pawl 10 is recessed into the drive plate 4, and the latching is released when the engine is started.

Next, the function of the hook 20 will be explained together with the operation of the starter 1.

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 in the direction of arrow A in FIG.
A concave portion 15a of the driven plate 15 that opens outward along 4a.
to go into. Therefore, each locking part 11a, 11b and 16
a, 16b are locked, and by further pulling out the rope 6, the drive plate 4 rotates with the cam plate 14 in the locked state (overcoming the frictional contact force of the cam plate 14), and the driven plate 15 and then the crank. Rotate the shaft and start the engine.

When the engine starts, the driven plate 15 rotates, and at this time, the locking pawl 10 is pushed inward by the rear rising portion 16c of the recess 16 of the driven plate 4 against the frictional force of the cam plate 14. Further, when the rotation of the drive plate 4 is stopped and the drive plate 4 is rotated in the opposite direction by rewinding the rope 6, the locking pawl 10 is moved inward along the cam plate 14 by the pressing force of the spring 12. Pushed.
Therefore, the locking between the locking pawl 10 and the driven plate 15 side is released. The tip of the locking claw 10 is connected to the cam plate 1.
4 to the fixed shaft 3 side along the cam surface 14a, and as shown in FIG.
are interlocked.

In the above embodiments, arbitrary changes such as the shape and quantity of the locking pawls 10, the shape of the hooking part 20, and other details such as the shape and configuration are permitted within the scope of the present invention. .

As is clear from the above description, the engine recoil starting device according to the present invention has a locking pawl that cooperates with a cam plate, and when the locking pawl is recessed into each opposing portion of the cam plate, the locking pawls engage in tandem and start the engine. Since a latching part is provided that allows the latching to be released when the latching occurs, there is no need to provide a protrusion prevention pawl or the like on the opposite side of the latching pawl from the pivoting part of the latching pawl, as in the conventional case. , the locking pawl can be made longer in a limited space.

Therefore, as mentioned at the beginning, the angle change when the locking pawl is locked is small and the bending stress and shearing force acting on the locking pawl can be effectively reduced, which improves the durability of the locking pawl and further The present invention can be provided as an engine recoil starting device that can improve reliability and extend life, and can also be expected to have a reliable and stable protrusion prevention effect of the locking pawl.

[Brief explanation of the drawing]

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.
2-line arrow view, Figure 3 is a perspective view of the cam plate and locking pawl,
FIG. 4 is an explanatory diagram of the function of the locking pawl. In the drawing, 3 is a fixed shaft, 4 is a rotating drive plate, and 10 is a fixed shaft.
1 is a locking pawl, 14 is a cam plate, 15 is a rotating driven plate, 2
0 is a hook part.

Claims (1)

[Scope of utility model registration request] A rotary drive plate pivotally supported on a fixed shaft, a rotary driven plate disposed coaxially with the drive plate, a locking pawl pivotally connected to the drive plate, and a cam plate pivotally supported on the fixed shaft in frictional contact. The locking pawl cooperates with the cam plate, protrudes outward to lock with the driven plate at startup, and returns inward to engage the drive plate after startup or when the drive plate rotates in the return direction. In the retractable recoil starter, one end side of the locking pawl is pivotally connected to the drive plate by a pivot, a locking part that locks with the driven plate is provided on the other end side of the locking pawl, and the cam plate and Each of the opposing parts of the locking pawl is provided with a locking part that locks together when the locking pawl is retracted and is released when the locking pawl projects outward for starting, A recoil starting device for an engine, characterized in that the stop portion is located between the lock portion of the lock portion pawl and the pivot shaft.