JPH058008Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a cutting edge separation concept for a small chainsaw suitable for cutting relatively hard synthetic resins, metals, lightweight concrete, etc.

(Prior art and its problems) Conventionally, relatively hard synthetic resins, metals, etc. have been cut using circular saws with rotary motion, jigsaws with reciprocating motion, or something in between the two using a pair of rotors. It has been proposed to drive a band saw, but the latter band saw has the disadvantage of being too large for on-site work, and for on-site work, circular saws with rotary motion or jigsaws with reciprocating motion are the mainstream, and portable Currently, hand saws are still widely used for this purpose. However, with a circular saw, there is a problem that not only the cutting width is limited to the radius of the circular saw, but also that it is difficult to cleanly cut through a so-called flat plate, which limits the range of use. On the other hand, with a jigsaw, the mechanism that converts the rotary motion of the motor into reciprocating motion not only reduces cutting efficiency, but also makes it difficult to make the drive unit compact.
The disadvantage is that the cutting depth is limited to the reciprocating distance. Furthermore, although it is easier to cut through a flat plate than with a circular saw, there remains the inconvenience of forming cutting introduction holes in advance.

Therefore, we aimed to create a compact motorized saw that would be as simple as a hand saw for cutting relatively hard synthetic resins and metals, making it easier to cut through flat plates, etc. Although the application of chain saws has been proposed, the chainsaws that have been put into practical use have mainly been improved for cutting soft wood (for example, U.S. Pat. No. 392,904), so as long as such chain saw structures are used, When cutting relatively hard synthetic resins, metals, lightweight concrete, etc., it is easy to cause tooth chipping and cracks in the cut material, and it also generates significant vibration, making it unsuitable for practical cutting. In view of these shortcomings, the inventors of the present invention have conducted extensive research and found that in order to cut relatively hard synthetic resins, metals, etc. with a chainsaw, it is first necessary to suppress the pivot action during cutting. This is important, and the first method is to minimize the cutting edge pitch by providing multiple cutting edges on one link instead of one cutting link in conventional wood chain saws. Instead of omitting the drive link used in wood chain saws, a drive recess is provided at the bottom of the center link to form a small-pitch saw chain, eliminating the need for a depth gauge like in conventional wood chain saws. By lowering the blade height, locating the connecting pin of the center link above the height center, and arranging multiple blades on one link, the pivot action energy can be used effectively. In addition to this, an attempt was made to reduce the pivot action (Japanese Patent Application No. 59-255643). In addition, as a second method, the bottom of the center link is made flat and the driving claw is removed from the bottom, and the flat bottom of the center link is brought into contact with and guided by the bottom of the groove provided on the periphery of the guide bar, and the center link is connected. The lower part of the side link is brought into contact with the upper part of the guide bar to reduce the pivot action of the entire chain link.
-255645), it reduces the load on the pin that connects the center link and side link, improves the strength of the saw chain, reduces the chain width, and solves the basic problem of downsizing chain saws. Settled. However, as the chain saw itself becomes smaller and thinner, a decrease in overall durability such as tensile strength is inevitable. A phenomenon of division at the cardinal branch was observed. Therefore, when we analyze the causes of this, Table 1 below shows an example of the saw chain dimensions and compares them. 1.7 25mm Center link total length 8 13.7mm Number of edges/1 link 5~6 1 piece Center link thickness 0/55~0.72 1.25mm Side link thickness 0.2~0.3 1.25mm Center link total height 5 14mm Exposed link height 3.3 9.7mm Link material The hardness is around HRC 60 and around 50, and there are large differences in the dimensions of the cutting links and side links that make up the saw chain, as well as the connection strength between them, depending on the hardness of the cutting material, and there are problems that arise due to these factors. It was concluded that without solving the problem, it would be impossible to provide a practical chain saw, even though the material is relatively hard compared to synthetic resin or other wood.

(Issues of the invention) The present invention solves the above-mentioned factors that cause the saw chain to split during cutting, since unlike a single saw, a chain saw is not integrated as a whole. Considering that the cutting torque applied to the cutting edge has a subtle effect, the aim is to improve the cutting durability of relatively hard materials with a small and thin chain saw from the viewpoint of the cutting mode.

(Means for Solving the Problems) In order to solve the above problems, the present invention was developed as a result of intensive research into the sorting mode and cutting edge cutting phenomenon. This is likely to occur at discontinuous points. In particular, the amount of work and work position of the first blade of the multiple cutting edges are greatly involved, increasing the pivot action and lateral blur torque during cutting, resulting in lateral twisting. When forming multiple cutting edges on a cutting link based on the knowledge that it may lead to separation,
When the first blade of the plurality of cutting edges 11 on each cutting center link 1 starts from the center of the cutting center link 1, the first blade
The generation of lateral vibration torque due to the blade is suppressed, and the adjacent center links 1, 1 at the front and rear
If the right and left cutting torques are balanced between the adjacent center links 1 and 1 by cutting in opposite directions so that they are left and right symmetrical between the saw chains, the cutting of the saw chain can be significantly improved. They discovered what could be done and completed the present invention.

In other words, the gist of the present invention is that ``the first blade 11C of the plurality of cutting edges 11 on each cutting center link 1 starts from the center in the left and right separation direction with the longitudinal direction of the cutting center link 1 as the center line. , the other continuous cutting edges are cut in only one direction, either to the left or right of the center line, and the adjacent center links 1, 1 at the front and rear are symmetrical to each other with the longitudinal direction as the center line of symmetry. They are connected so that they are cut in opposite directions, and the cutting edges of the adjacent center links 1, 1 are configured to clear the entire cutting width of the chase saw.

The present invention is based on the premise that the cutting link forming the center link is provided with a plurality of edges, but the number of edges varies depending on the dimensions of the center link and is usually about 3 to 8.

In the sifting mode, the first blade starts from the center, and as shown in FIGS. 1 and 2, is arranged in opposite directions so as to be symmetrical between the front and rear center links 1, 1. Although necessary, the present invention is not limited to the specific embodiment of five blades shown in FIGS. 3 and 4, and various embodiments may be adopted depending on the number of blades. However, since the amount of work required for the outermost edge is greater than the other edges, it is preferable to provide more edges than other edges.

In addition, in order to suppress the amount of work of the first blade located at the center as much as possible, as shown in Figure 2, it is necessary not only to start the first blade of the cutting edge from the center, but also to start the last blade at the center or from the center. If the first blade of the center link 1 following the last blade of the front center link 1 is continuous with the last blade of the front center link 1, the amount of work of the first blade can be suppressed (see comparison of Figures 9a and 9b). , is preferable because, in combination with the above-mentioned effect, the separation durability of the saw chain is further improved.

Hereinafter, the configuration of the present invention will be explained in detail based on the accompanying drawings showing specific examples thereof.

(Example) Fig. 1 and Fig. 2 are conceptual diagrams showing the cutting edge arrangement form according to the present invention, and Fig. 3 and Fig. 4 are specific examples of sorting the cutting edges shown in Fig. 1 and Fig. 2. FIG.

FIG. 5 is a perspective view of a small chain saw employing the structure of the present invention, FIG. 6 is an assembled and exploded perspective view of the same, and FIG. 7 is a front view showing details of the main structure.

In the drawing, M is a small portable chainsaw,
An endless saw chain C is formed by pivotally connecting an even number of cutting center links 1 having an appropriate number of cutting edges with a pin P so as to sandwich them via a pair of side links 2, 2, on a guide bar 3. The chain sprocket 4 is rotated by meshing the teeth of the chain sprocket 4 with a recess formed in the base of the cutting link 1.
As shown in FIG. 6, in this chain saw M, a guide rod 71 that guides the protruding tip of the handle 6 during cutting is guided by a stop 7 that projects downward and a stop 7 that does not have a guide rod. Long hole 32 of bar 3,
A drive shaft 8 is mounted so that the tension of the saw chain C can be adjusted with bolts B and B so as to sandwich 32, and is mounted on a bearing 61 located at the protruding center of the handle 6, and is rotationally driven by a motor (not shown). The components of the chain sprocket 4 are assembled so that they are connected by keyways.

Further, the tip of the guide bar 3 is formed in an arc shape like a general chain saw, and a guide bar groove 31 for guiding the saw chain C is formed around the guide bar 3. ing. On the other hand, the chain sprocket 4 is arranged on the base side of the guide bar 3, and is attached to a drive shaft 8 that is operatively connected to a rotational drive device such as a motor (not shown) mounted on the handle 32.

The sorting chain C has a plurality of cutting center links 1... and a plurality of side links 2, which are extremely thin compared to the center link 1, at a position displaced above the height center position of the center link 1. They are pivotally connected to each other by pins P, and are configured in an endless shape as a whole.

Cutting edges 11 . . . are arranged on the center link 1 as conceptually shown in FIGS. 1 and 2. As shown in FIGS.

Specifically, as shown in FIG. 3, a suitable number (five in the drawing) of cutting edges 11 forming set teeth are aligned in the saw chain traveling direction (the first
Starting from the center edge 11C as shown in the arrow A) and gradually increasing the cutting angle to the right, move the right cutting edges 11R'', 11R',
11R, 11R, and then on the center link 1, move toward the cutting edge direction (arrow A in Fig. 1) and gradually increase the cutting angle to the left starting from the center edge 11C, and then move to the left cutting edge 11L. ″、11L′、11L、
11L, and by repeating this process, evenly spaced edge pitches are formed as a whole (see FIG. 7).

On the other hand, in the case of Fig. 2, as shown in Fig. 4, a series of cutting edges 11 . Formerly Center Edge 1
Starting with 1C and gradually increasing the cutting angle to the right, move the right cutting edge 11R',
After forming 11R and 11R, the final blade returns to the center edge 11C via 11R' again, and the next center link 1 moves toward the saw chain traveling direction (arrow A in Fig. 1) and reaches the center edge 1.
Starting from 1C and gradually increasing the cutting angle to the left, move the left cutting edge 11L', 1.
After forming 1L and 11L, the final blade returns to the center edge 11C via 11L' again, and by repeating this process, the edge pitches are formed at equal intervals as a whole (see Fig. 7). The plurality of cutting edges 11 on the center link 1 are designed to clear the entire width of the chain saw by dividing the front and rear cutting center links 1, 1. On the other hand, on the base side, chain sprocket 4
A recess 12 is formed in which the teeth 41 engage. Therefore, the saw chain C engages with the teeth 41 of the chain sprocket 4 and the base recess 12 of the cutting center link, is rotationally driven in the direction of arrow A, and travels in the direction of arrow B. At this time, since the cutting link 1 is configured to be pivotally connected by a plurality of side links 2 which are extremely thin compared to the cutting link 1, the saw chain C
does not have sufficient strength in the torsional direction and tends to swing left and right, but it travels while being held and guided by the guide groove 31 of the guide bar 3 while being restrained from swinging left and right. On the other hand, when cutting the material to be cut, the leading cutting edge 11 of the cutting link 1
The cutting ring 1 tends to pivot when the R bites into the material to be cut.
The base of the cutting link 1 is the guide groove 31.
The pivot action of the cutting link 1 is suppressed because the pivotal connection portion with the side link 2 is displaced toward the cutting edge.

Furthermore, even when the saw chain C is rotated by the chain sprocket 4, it is prevented from swinging to the left and right, and the driving force is accurately transmitted.
In order to achieve a smooth transition from chain sprocket 4 of saw chain C to guide bar 3,
A cutting link that meshes with the teeth of the chain sprocket 4 by attaching polygonal guide plates 5, 5 to the drive shaft 8 on both sides of the chain sprocket 4 so as to rotate in synchronization with the chain sprocket 4. Both guide plates 5, 5 near the base recess 12 of 1
The saw chain C is rotated while being guided by the chain sprocket 4, and the shape of the valley 42 between the teeth 41, 41 of the chain sprocket 4 meshes with the chain sprocket 4. Corresponding to the bend, it forms a mountain shape that rises toward the center of the other part.

(Operation and effect of the invention) As is clear from the above explanation, the saw chain C is formed by pivotally connecting the cutting center link 1 having a plurality of cutting edges with a pin via a pair of side links 2, 2. In the chainsaw M, which has achieved miniaturization, the cutting edge on the cutting center link is the 9th cutting edge.
As shown in the figure, since the cutting progresses while gradually increasing the cutting depth, the lateral blur torque that inevitably occurs during cutting is likely to occur due to the cutting, but in this invention, the front and rear adjacent center links 1, Between 1 and 1, the cutting edges are symmetrical and facing in opposite directions to the left and right in a well-balanced manner, which eliminates uneven distribution of cutting torque and allows the first cutting edge on each center link to Since the working position of the first blade is located at the center, (9th
(See Figures a and b), the problematic first blade does not cause any lateral wobbling phenomenon. Therefore, the lack of strength in the horizontal torsional direction of the chain link, which was seen as a durability problem in such compact chain saws, does not become a problem in cutting, and it is virtually possible to cut and part off relatively hard workpieces. Since it is possible to provide a chainsaw that is possible, its practical value is worth mentioning in detail.

[Brief explanation of the drawing]

1 and 2 are conceptual diagrams showing the basic aspects of the cutting edge arrangement structure according to the present invention,
3 and 4 are top end views showing details of the cutting process shown in FIGS. 1 and 2, and FIG. 5 is a perspective view showing the entire small chain saw to which the present invention is applied, excluding the drive motor section. FIG. 6 is an exploded perspective view of FIG. 5. Fig. 7 is a partially cutaway front view, Fig. 8 is a sectional view taken along the - line, and Fig. 9 is a conceptual diagram of cutting progress by the cutting edge according to the present invention, in which the cutting depth is increased in order from the first blade. However, the cutting is progressing. Figures a and b are schematic cutting conceptual diagrams showing the primary cutting mode of each blade and the secondary cutting mode (hatched portion) of the first blade in such a state of cutting progress. 1...Cutting center link, 2...Side link, 3...Guide bar, 4...Chain sprocket, 5...Guide plate, 11R~11L
... Cutting edge.

Claims (1)

[Scope of claim for utility model registration] A cutting center link 1 having a plurality of cutting edges is connected to a pair of side links 2 and 2.
A saw chain C, which is pivotally connected with a pin through
In the chainsaw M, which is configured to be rotated by engaging with the bottom recess of the cutting center link 1, the first blades 11C of the plurality of cutting edges 11 on each cutting center link 1 extend in the longitudinal direction of the cutting center link 1. The center line starts from the center in the left and right dividing direction, and the other continuous cutting edges are divided only in one direction, either left or right of the center line, and the front and rear adjacent center links 1, 1 are line-symmetrical in the longitudinal direction. They are connected so that they are cut in opposite directions so that they are symmetrical about the center line, and the cutting edge of the adjacent center links 1 and 1 is configured to clear the entire cutting width of the chase saw. The cutting edge is characterized by a separating structure.