Guide bar and chain saw

Abstract

[Problem] To provide a technique capable of making damage unlikely to occur at a joining spot of sheet-like members constituting a guide bar. [Solution] One aspect of the present invention provides a guide bar. This guide bar comprises three sheet-like members, which are a first metal sheet, a second metal sheet, and a resin sheet. A first surface of the resin sheet and a first inner surface of the first metal sheet make contact with each other. A second surface of the resin sheet and a second inner surface of the second metal sheet make contact with each other. Joining spots are provided to integrally join the three sheet-like members, at a plurality of spots in a region where the three sheet-like members overlap. A lateral surface of the resin sheet, the first inner surface, and the second inner surface form a groove through which a saw chain passes.

Description

Guide bars and chainsaws

[0001] The present invention relates to a guide bar and a chainsaw.

[0002] Patent Document 1 discloses a guide bar in which a synthetic resin is filled between side plates to form a middle plate, and the side plates and the middle plate are joined together with the synthetic resin.

[0003] Japanese Patent Application Laid-Open No. 2020-104292

[0004] In the guide bar of Patent Document 1, the side plates and the middle plate are joined together over the entire surface where they come into contact with each other, so if the guide bar is twisted or deformed, the joined surfaces are prone to peeling and other damage.

[0005] In view of the above circumstances, the present invention provides a technique that can make it difficult for breakage to occur at the joints between the plate-like members that make up the guide bar.

[0006] According to one aspect of the present invention, a guide bar is provided. The guide bar includes three plate-like members: a first metal plate, a second metal plate, and a resin plate. A first surface of the resin plate contacts a first inner surface of the first metal plate. A second surface of the resin plate contacts a second inner surface of the second metal plate. Joints are provided at multiple locations in the overlapping area of ​​the three plate-like members, joining the three plate-like members together. A groove through which a saw chain passes is formed by the side surfaces of the resin plate, the first inner surface, and the second inner surface.

[0007] According to the present invention, damage to the joints between the plate-like members that make up the guide bar can be made less likely to occur.

[0008] Fig. 1 is a block diagram showing the overall configuration of a chainsaw 1. Fig. 2 is a diagram showing the appearance of a guide bar 10 as viewed from the left side. Fig. 3 is a diagram showing the appearance of a guide bar 10 as viewed from the right side. Fig. 4 is a diagram showing plate-shaped members 100 before joining. Fig. 5 is a diagram showing plate-shaped members 100 that have been brought into close contact with each other. Fig. 6 is a diagram showing plate-shaped members 100 that have been joined. Fig. 7 is a diagram showing an example of a rivet with a different shape. Fig. 8 is a diagram showing an example of a resin plate with a different shape.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Various features shown in the following embodiments can be combined with each other.

[0010] <Embodiment> Fig. 1 is a block diagram showing the overall configuration of a chainsaw 1. Fig. 1 shows the chainsaw 1 as seen from the left. The chainsaw 1 includes a main body 2, a working unit 3, a drive unit 5, and a battery 6. The main body 2 is the main body of the chainsaw 1 and stores and holds the drive unit 5 therein. The main body 2 also holds the working unit 3 exposed to the outside and holds the battery 6 in a detachable manner. The main body 2 has a front handle 21, a rear handle 22, and a lever 23.

[0011] The front handle 21 and the rear handle 22 are grips that the operator grasps when performing work using the chainsaw 1. The lever 23 is an operator that the operator operates to activate the chainsaw 1. When the operator performs work using the chainsaw 1, the working unit 3 comes into contact with the work object and acts directly on the work object. In this embodiment, the work object is a tree, a board, or the like, and the working unit 3 acts to cut them. The working unit 3 includes a saw chain 4 and a guide bar 10.

[0012] The guide bar 10 is a plate-shaped member extending in the front-to-rear direction, and the rear end of the guide bar 10 is attached to the main body 2. The guide bar 10 has a groove formed on its outer periphery, along which the annular saw chain 4 is wound. The saw chain 4 has multiple top blades and multiple drive links, both made of metal, which are connected together. The multiple drive links pass through the grooves of the guide bar 10, causing the saw chain 4 to rotate around the outer periphery of the guide bar 10.

[0013] The drive unit 5 has a motor, drive gears, etc., and operates using power supplied from the battery 6 to rotate the saw chain 4. The drive unit may have an internal combustion engine instead of a motor. As the saw chain 4 rotates, the multiple top blades cut the work object. As described above, the chainsaw 1 includes the guide bar 10, the saw chain 4 that passes through the grooves of the guide bar 10, and the drive unit 5 that drives the saw chain 4.

[0014] FIG. 2 is a diagram showing the appearance of the guide bar 10 as viewed from the left side. FIG. 3 is a diagram showing the appearance of the guide bar 10 as viewed from the right side. The guide bar 10 includes three plate-shaped members 100: a first metal plate 11, a second metal plate 12, and a resin plate 13. The first metal plate 11 and the second metal plate 12 are formed from a metal such as iron or an alloy, but other metals may be used as materials as long as they have the strength required for the guide bar 10. The resin plate 13 is formed from a synthetic resin. It is desirable that the synthetic resin used for the resin plate 13 has excellent heat resistance and oil resistance.

[0015] The first metal plate 11 has first joints 111-01, 111-02, ..., 111-35 (hereinafter referred to as "first joints 111" when there is no need to distinguish between them) and first cutouts 112-1, 112-2, 112-3 (hereinafter referred to as "first cutouts 112" when there is no need to distinguish between them). The first joints 111 are areas where processing is performed to join the three plate-like members 100 together. In this embodiment, the first joints 111 have holes formed therein for inserting rivets, and the three plate-like members 100 are joined by the rivets inserted into the holes.

[0016] Furthermore, 35 first joints 111 are evenly provided on the first metal plate 11 from the tip (nose) to the base (mount). Of the first joints 111, first joints 111-01 to 111-17 are provided on the upper side, and first joints 111-19 to 111-35 are provided on the lower side, sandwiching first joint 111-18. The first lightening portions 112 are portions removed from the first metal plate 11 to reduce weight. The resin plate 13 bonded to the first metal plate 11 is visible through each of the first lightening portions 112.

[0017] The second metal plate 12 has second joint portions 121-01, 121-02, ..., 121-35 (hereinafter referred to as "second joint portions 121" when there is no need to distinguish between them) and second cutout portions 122-1, 122-2, 122-3 (hereinafter referred to as "second cutout portions 122" when there is no need to distinguish between them). The second joint portion 121 is a portion where a process is performed to join the three plate-like members 100 together. In this embodiment, the second joint portion 121 has holes formed therein for inserting rivets, and the three plate-like members 100 are joined by the rivets inserted into the holes.

[0018] Additionally, 35 second joints 121 are evenly provided on the second metal plate 12 from the tip (nose) to the base (mount). Of the second joints 121, second joints 121-01 to 121-17 are provided on the upper side, and second joints 121-19 to 121-35 are provided on the lower side, sandwiching second joint 121-18. The second lightening portions 122 are portions removed from the second metal plate 12 to reduce weight. The resin plate 13 bonded to the second metal plate 12 is visible through each of the second lightening portions 122.

[0019] The guide bar 10 is formed by overlapping and joining a first metal plate 11, a second metal plate 12, and a resin plate 13. The procedure for joining these three plate-shaped members 100 will be described with reference to Figures 4 to 6. Figure 4 is a diagram showing the plate-shaped members 100 before joining. Figure 5 is a diagram showing the plate-shaped members 100 that have been tightly attached. Figure 6 is a diagram showing the joined plate-shaped members 100. Figure 6 shows the three plate-shaped members 100 as seen in the direction of the arrows A-A shown in Figure 2.

[0020] First, a description will be given with reference to Figure 4. The first metal plate 11 has a first joint portion 111, a first cutout portion 112, a first inner surface 113, and a first outer surface 114. The second metal plate 12 has a second joint portion 121, a second cutout portion 122, a second inner surface 123, and a second outer surface 124. The resin plate 13 has a joint portion 131, a first surface 132, a second surface 133, a central portion 134, a first filling portion 135, and a second filling portion 136.

[0021] The first inner surface 113 is one of two flat surfaces (surfaces that are not side surfaces) that the first metal plate 11 has, and is the surface that faces the resin plate 13 (i.e., the inside). The first outer surface 114 is the surface that faces the opposite side (i.e., the outside) from the first inner surface 113. Here, when viewed from the first metal plate 11 and the second metal plate 12, the side of the space sandwiched between the first metal plate 11 and the second metal plate 12 (the space in which the resin plate 13 is arranged) is the inside, and the side opposite to that space is the outside.

[0022] The second inner surface 123 is one of two flat surfaces (surfaces that are not side surfaces) that the second metal plate 12 has, and is the surface that faces the resin plate 13 (i.e., the inside). The second outer surface 124 is the surface that faces the opposite side (i.e., the outside) from the second inner surface 123. The first surface 132 is one of the surfaces that the resin plate 13 has, and is the surface that faces the first metal plate 11. The second surface 133 is one of the surfaces that the resin plate 13 has, and is the surface that faces the second metal plate 12.

[0023] The first joint portion 111, the joint portion 131, and the second joint portion 121 have holes for inserting rivets, and are located at positions where the holes will be continuous when the three plate-like members 100 are stacked. The first lightening portion 112 forms a space B1 in the center of the first metal plate 11 for weight reduction. The second lightening portion 122 forms a space B2 in the center of the second metal plate 12 for weight reduction.

[0024] The first filling portion 135 is formed in a position and shape that fills the space B1 when the first metal plate 11 and the resin plate 13 are joined. The second filling portion 136 is formed in a position and shape that fills the space B2 when the second metal plate 12 and the resin plate 13 are joined. The central portion 134 is a plate-shaped portion of the resin plate 13 excluding the first filling portion 135 and the second filling portion 136.

[0025] Next, a description will be given with reference to Figure 5. As shown in Figure 5, in the guide bar 10, the first surface 132 of the resin plate 13 is in contact with the first inner surface 113 of the first metal plate 11, and the second surface 133 of the resin plate 13 is in contact with the second inner surface 123 of the second metal plate 12. In addition, in the guide bar 10, the first filling portion 135 of the resin plate 13 is fitted into the space B1 formed by the first lightening portion 112 of the first metal plate 11, and the second filling portion 136 of the resin plate 13 is fitted into the space B2 formed by the second lightening portion 122 of the second metal plate 12.

[0026] 5, a continuous hole C1 is formed by the first joint portion 111, the joint portion 131, and the second joint portion 121. A rivet is inserted into the hole C1 and crimped, thereby joining the three plate-like members 100.

[0027] Next, a description will be given with reference to Figure 6. A rivet 16 is attached to the hole C1. The rivet 16 is a rivet that has a cylindrical or cylindrical shaft portion and both ends are crimped (a process that deforms the ends of the rivet) to form a round head. In this way, the guide bar 10 is provided with joints at multiple locations in the area where the three plate-like members 100 overlap (hereinafter referred to as the "overlapping area") where the three plate-like members 100 are joined together to form a single unit.

[0028] The overlapping region is, for example, a region where three plate-like members 100 appear to overlap when the guide bar 10 is viewed from the normal direction F1 of the first surface 132 of the resin plate 13. In other words, the overlapping region is a region where the first inner surface 113 of the first metal plate 11 and the first surface 132 of the resin plate 13 contact each other, and a region where the second inner surface 123 of the second metal plate 12 and the second surface 133 of the resin plate 13 contact each other.

[0029] In this embodiment, the multiple joint locations are the locations where the multiple first joints 111 and the multiple second joints 121 shown in FIG. 2 are provided. The use of resin plates 13 in the guide bar 10 achieves a lighter weight than when all metal plates are used. However, in the case of heterogeneous joints where metal plates and resin plates are mixed, spot welding, for example, would melt the resin and make the joint impossible. In this embodiment, the above-mentioned joint locations are joined with rivets, so even heterogeneous joints including metal and resin can be joined without causing inconveniences such as melting the resin.

[0030] In this embodiment, the first metal plate 11 and the second metal plate 12 are hollowed out at the center, and the resin plate 13 has a shape that fills the hollowed-out space B1 of the first metal plate 11 and the hollowed-out space B2 of the second metal plate 12. If the hollowed-out spaces are left empty, chips (wood chips) may accumulate in the spaces during work, which may deteriorate workability, but by filling the spaces with the resin plate 13, it is possible to prevent such chips from accumulating.

[0031] Furthermore, in the guide bar 10 formed by joining three plate-like members 100 as described above, the groove E1 through which the saw chain 4 passes is formed by the side surface 137 of the resin plate 13, the first inner surface 113 of the first metal plate 11, and the second inner surface 123 of the second metal plate 12. In other words, the bottom surface of the groove E1 is formed from resin. In contrast, in a conventional guide bar formed by joining three metal plates with rivets, the bottom surface of the groove through which the saw chain passes is also formed from metal.

[0032] As described above, the saw chain 4 passing through the groove E1 is made of metal. Therefore, if the bottom of the groove is made of metal, contact of the saw chain 4 with the bottom of the groove will lead to damage to the saw chain 4, so it is necessary to leave a certain distance (for example, about 2 mm to 3 mm) between the bottom of the groove and the saw chain 4. Here, lubricating oil is supplied to the groove through which the saw chain 4 passes to smooth the rotation of the saw chain 4, but the wider the gap between the bottom of the groove and the saw chain 4, the more difficult it is for the lubricating oil to be transported in the direction of rotation, reducing the effectiveness of the lubricating oil.

[0033] On the other hand, in the guide bar 10 of this embodiment, even if the saw chain 4 comes into contact with the side surface 137 that forms the bottom surface of the groove E1, the side surface 137, which is made of resin, is scraped away. Therefore, compared to when the bottom surface of the groove is made of metal, there is no need to worry about the saw chain 4 being damaged even if the position of the side surface 137 is brought as close as possible to the saw chain 4. As a result, the lubricating oil is more easily transported in the direction of rotation, and the effectiveness of the lubricating oil can be increased.

[0034] Furthermore, let us assume that the joint between the three plate-like members 100 is the entire overlapping area of ​​the three plate-like members 100. In this case, for example, if the guide bar 10 is bent or twisted due to a force from the work object, the surface facing outward of the bend will stretch more than the surface facing inward. In this state, the two surfaces of the two plate-like members (the first metal plate 11 and the resin plate 13, and the resin plate 13 and the second metal plate 12) that contact each other have different degrees of stretch, so a force acts on the two surfaces to move apart. However, because the entire surfaces are joined, separation may occur at the joint.

[0035] In contrast, in the guide bar 10, the three plate-like members 100 are not joined over the entire overlapping region, but are joined at multiple locations in the overlapping region where the first joint 111 and the second joint 121 are provided, and are not joined at other locations. Therefore, if the guide bar 10 is bent, the resin plate 13 can shift or expand and contract at the unjoined locations. As such, according to this embodiment, damage to the joints between the plate-like members that make up the guide bar is less likely to occur than when the three plate-like members 100 are joined over the entire region where they are in contact with each other (i.e., the overlapping region).

[0036] <Other Embodiments> The shape of the rivet is not limited to those described in the embodiments. Fig. 7 is a diagram showing an example of a rivet with a different shape. Fig. 7 shows a guide bar 10a joined with a rivet 16a having a different shape from the rivet 16 shown in Fig. 6. For ease of understanding, Fig. 7 shows the rivet 16a before and after crimping.

[0037] The rivet 16a has a flange 161a at the center in the axial direction F2. The flange 161a is a protruding portion that protrudes from the columnar or cylindrical portion of the rivet 16a and has a thickness G1 common to the resin plate 13 in the overlapping region. In the example of Figure 7, a continuous hole C1a is formed by the first joint portion 111, the joint portion 131a, and the second joint portion 121. The joint portion 131a forms a hole of a size that allows the flange 161a to be inserted.

[0038] By providing the flange 161a in this manner, even if the resin of the resin plate 13 deteriorates, the flange 161a continues to maintain the distance between the first metal plate 11 and the second metal plate 12, thereby preventing the rivet from loosening compared to when the flange 161a is not provided.

[0039] The rivet 16a has end portions 162a that form hollow spaces H16 at both ends in the axial direction F2, and the end portions 162a are pressed into the hollow spaces H16. This configuration allows both ends of the rivet that have been deformed by the crimping process to escape into the hollow spaces H16, making the rivet protrusion smaller than when the hollow spaces H16 are not formed. Furthermore, if the size of the hollow spaces H16 is sufficiently large, it is possible to completely eliminate protrusions from the first outer surface 114 of the first metal plate 11 and the second outer surface 124 of the second metal plate 12.

[0040] Furthermore, the multiple joints provided in the overlapping region of the guide bar may be joined by pressing the resin plate 13 against fine undulations provided on the first inner surface 113 of the first metal plate 11 and the second inner surface 123 of the second metal plate 12. According to this aspect, it is possible to prevent undulations from occurring on the outer surfaces (first outer surface 114 and second outer surface 124) of the joints (first joint portion 111 and second joint portion 121) of the metal plates (first metal plate 11 and second metal plate 12).

[0041] The shape of the resin plate is not limited to that described in the embodiment. FIG. 8 is a diagram showing an example of a resin plate with a different shape. FIG. 8 shows a guide bar 10b including a resin plate 13b having a different shape from the resin plate 13 shown in FIG. 4 and the like. The resin plate 13b does not have the first filling portion 135 and the second filling portion 136 shown in FIG. 4, and has a shape including only a central portion 134. Even in this case, the effect of the lubricating oil can be enhanced, as in the case of the resin plate 13. Furthermore, the weight can be further reduced compared to when the first filling portion 135 and the second filling portion 136 are included.

[0042] The shape of the metal plate is not limited to that described in the embodiment. For example, it does not have to be hollowed out. Even in this case, by using a resin plate, it is possible to reduce the weight compared to when the entire plate is made of metal, and the effectiveness of the lubricating oil can be improved. Furthermore, the shape of the guide bar is not limited to that described in the embodiment. For example, a replaceable sprocket may be provided at the tip of the guide bar.

[0043] The method for manufacturing the guide bar 10 is not limited to that described in the embodiment. For example, the first metal plate 11 and the second metal plate 12 are arranged as shown in Figure 5 and are enclosed to form a mold. At this time, the first joint portion 111 and the second joint portion 121 are sealed to prevent synthetic resin from flowing into them. Then, heated and melted synthetic resin may be poured into the mold and cooled to form the resin plate 13.

[0044] <Additional Notes> Furthermore, the present invention may be provided in the following aspects.

[0045] (1) A guide bar comprising three plate-like members: a first metal plate, a second metal plate, and a resin plate; a first surface of the resin plate contacts a first inner surface of the first metal plate; a second surface of the resin plate contacts a second inner surface of the second metal plate; joints are provided at multiple locations in the area where the three plate-like members overlap, joining the three plate-like members to form a single unit; and a groove through which a saw chain passes is formed by the sides of the resin plate, the first inner surface, and the second inner surface.

[0046] According to this aspect, damage to the joints of the guide bars can be made less likely to occur.

[0047] (2) The guide bar according to (1) above, wherein the joints are joined by rivets.

[0048] According to this aspect, bonding can be achieved without melting the resin.

[0049] (3) A guide bar as described in (2) above, wherein the rivet has a flange in the axial center, and the flange has a thickness that is the same as that of the resin plate in the area where the three plate-shaped members overlap.

[0050] According to this aspect, even if the resin deteriorates, the loosening of the rivet can be suppressed.

[0051] (4) In the guide bar described in (3) above, the rivet has two ends that form hollow spaces at both ends in the axial direction, and the two ends are pressed into the hollow spaces.

[0052] According to this aspect, the projection of the rivet can be made smaller.

[0053] (5) In the guide bar described in (1) above, the joint is formed by pressing the resin plate against undulations provided on the first inner surface and the second inner surface.

[0054] According to this aspect, it is possible to prevent undulations from occurring on the outer surfaces of the joints of the metal plates.

[0055] (6) A guide bar according to any one of (1) to (5) above, wherein the first metal plate and the second metal plate are hollowed out at the center, and the resin plate has a shape that fills the hollowed-out space of the first metal plate and the second metal plate.

[0056] According to this aspect, it is possible to prevent chips from remaining in the hollowed-out space.

[0057] (7) A chainsaw including the guide bar according to any one of (1) to (6) above, the chainsaw including a saw chain passing through the groove of the guide bar and a drive unit that drives the saw chain. Of course, this is not a limitation. Furthermore, the above-described embodiments and modifications may be combined in any desired manner.

[0058] Finally, while various embodiments of the present invention have been described, these are presented by way of example only and are not intended to limit the scope of the invention. The novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. The embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as defined in the appended claims.

[0059] DESCRIPTION OF SYMBOLS 1: Chainsaw 3: Working part 4: Saw chain 10: Guide bar 11: First metal plate 12: Second metal plate 13: Resin plate 16: Rivet 100: Plate-shaped member 111: First joint portion 112: First lightening portion 113: First inner surface 114: First outer surface 121: Second joint portion 122: Second lightening portion 123: Second inner surface 124: Second outer surface 131: Joint portion 132: First surface 133: Second surface 134: Central portion 135: First filling portion 136: Second filling portion 137: Side surface 161a: Flange 162a: Both ends

Claims

1. A guide bar, comprising: Three plate-like members, namely a first metal plate, a second metal plate, and a resin plate; A first surface of the resin plate is in contact with a first inner surface of the first metal plate; A second surface of the resin plate is in contact with a second inner surface of the second metal plate; Bonding locations are provided at a plurality of locations in a region where the three plate-like members overlap, such that the three plate-like members are joined together; A guide bar, in which a groove through which a chain passes is formed by a side surface of the resin plate, the first inner surface, and the second inner surface.

2. The guide bar according to Claim 1, wherein: The bonding locations are joined by rivets.

3. The guide bar according to Claim 2, wherein: The rivet has a flange at the center in the axial direction, and the flange has the same thickness as the resin plate in a region where the three plate-like members overlap.

4. The guide bar according to Claim 3, wherein: The rivet has both ends that form hollow spaces at both ends in the axial direction, and the both ends are pushed into the hollow spaces.

5. The guide bar according to Claim 1, wherein: The bonding locations are joined by pressing the resin plate against undulations provided on the first inner surface and the second inner surface.

6. The guide bar according to Claim 1, wherein: The first metal plate and the second metal plate are centrally hollowed out; The resin plate has a shape that fills the hollowed-out spaces of the first metal plate and the second metal plate.

7. A chainsaw comprising the guide bar according to any one of Claims 1 to 6, comprising: A chain passing through the groove of the guide bar; and A drive unit for driving the chain.