JP2009279882A - Chain saw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chain saw with its engine fixed to its housing by a method excellent in oscillation characteristics. <P>SOLUTION: An engine 50 is covered with a housing 2 over two opposed sides perpendicular to a shaft direction of a crankshaft 51 and is fixed by two bolts 31, 32 and two bolts 33, 34 respectively to first (upper) side and its opposite (lower) side. The chain saw excellent in oscillation characteristics is achieved by arranging the bolts 31-34 as follows: in projection view from one side, a line connecting two first side bolts 31, 32 and a line connecting two opposite side bolts 33, 34 intersect in a domain between a crankshaft and a crankcase and cylinder join line while the line connecting first side bolts and the line connecting opposite side bolts respectively intersect the elongation of the crankshaft. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a chain saw that rotates a saw chain using a small engine.

A chain saw driven by a small engine such as a two-cycle engine is widely used as a tool for cutting tree trunks and branches. Chainsaws are usually operated by workers holding them, especially because they can cut overhead branches or climb on trees, so they can be easily lifted with one hand. It is important to be small and light. In order to reduce the size of the chainsaw, the engine body, exhaust pipe, saw chain, etc. are arranged and attached to the housing. (See Patent Document 1).
JP 61-160201 A

  In recent chainsaws, the engine body is housed in an integrally molded housing, and a saw chain part or the like is attached via the housing. However, since the housing is made of plastic for weight reduction, compared to a metal housing Since the rigidity and strength of the material itself are inferior, it was necessary to devise the design and production.

  The present invention has been made in view of the above background, and an object of the present invention is to provide a chainsaw capable of performing a stable operation of a saw chain while achieving a reduction in size and weight.

  Another object of the present invention is to provide a chainsaw in which an engine is fixed to a housing by a method having excellent vibration characteristics.

  Of the inventions disclosed in the present application, typical features will be described as follows.

  According to one aspect of the present invention, the engine includes a crankcase, a cylinder attached to the crankcase, an engine having a piston that reciprocates within the cylinder, a housing that houses the engine, and a guide bar attached to the housing. In a chain saw that rotates a saw chain wound around a guide bar by the engine, the engine is covered with a housing on two surfaces substantially parallel to the axial direction of the crankshaft, for example, the upper and lower surfaces, and fixed on each of the two surfaces by two bolts. Is done. These bolts are arranged when a straight line passing through two bolts on one surface and a straight line passing through two bolts on the other surface are drawn when viewed from one surface (for example, the upper surface). One surface and the other surface so that at least one straight line is inclined with respect to the crankshaft, and the straight line passing through the two bolts on one surface and the straight line connecting the two bolts on the other surface are not parallel Bolts are placed. At this time, it is preferable to arrange the bolts so that the straight line passing through the two bolts on one side and the straight line passing through the two bolts on the opposite side are inclined with respect to the crankshaft. More preferably, the directions are different with respect to the crankshaft.

  According to another feature of the present invention, the crankcase is divided in a plane perpendicular to the crankshaft, the two bolts on one side are attached to the divided crankcase one by one, and 2 on the other side. One bolt is attached to each divided crankcase. At that time, the four bolts provided on one surface and the other surface can be arranged at different positions when projected from one surface. The screw hole for attaching the bolt may be formed in a direction perpendicular to the moving direction of the piston. Further, on the side of the housing where the guide bar is attached, the crankcase is preferably fixed to the housing with a lateral bolt.

  According to still another aspect of the present invention, a crankcase, a cylinder attached to the crankcase, an engine having a piston that reciprocates in the cylinder, a housing that houses the engine, and a guide bar attached to the housing, In a chain saw that rotates a saw chain wound around a guide bar by an engine, the crankcase has two bolt holes on one side and the other side perpendicular to the crankshaft of the crankcase, and passes through two bolts on one side Bolt holes are formed so that the straight line and the straight line passing through the two bolts on the other side have different inclinations, and the engine is fixed to the housing by screwing the bolt into the bolt hole. The crankcase is divided by a plane perpendicular to the crankshaft so that the vertical distance from the two bolt holes on one side to the dividing surface is different from the vertical distance from the two bolt holes on the other side to the dividing surface. I made it.

  According to the invention of claim 1, at least one of the straight line passing through the two bolts on one surface and the straight line passing through the two bolts on the other surface is inclined with respect to the crankshaft. Since the bolts are arranged so that the straight line passing through the two bolts on the surface and the straight line connecting the two bolts on the other surface are not parallel, the bolts on one surface and the other surface are viewed from the axial direction of the crankshaft. The force in the direction in which the engine rotates relative to the housing with the fixed portion as a fulcrum can be reduced.

  According to the invention of claim 2, the straight line passing through the two bolts on one side and the straight line passing through the two bolts on the opposite side are inclined with respect to the crankshaft, so the engine viewed from one side Can reduce the force in the direction of rotation with respect to the housing.

  According to the invention of claim 3, since the bolt is arranged to be tightened in a direction perpendicular to the moving direction of the piston, the engine is effectively fixed to the housing against a reaction force against the reciprocating motion of the piston. Can do.

  According to the invention of claim 4, since the four bolts have different positions when projected from one surface, the fulcrum rotating by the vibration of the engine can be dispersed, so that the vibration of the engine is transmitted to the housing. Can be effectively reduced.

  According to the invention of claim 5, since the inclination directions of the straight line passing through the two bolts on one surface and the straight line passing through the two bolts on the other surface are different from each other with respect to the crankshaft, Can also be effectively reduced.

  According to invention of Claim 6, a crankcase is divided | segmented by the surface perpendicular | vertical to a crankshaft, two bolts of one surface are attached to the divided crankcase one by one, and two bolts of the other surface are attached. Since the bolts are attached one by one to the divided crankcase, a crankcase that is easy to manufacture and has good workability can be manufactured.

  According to the seventh aspect of the present invention, since the crankcase is fixed to the housing and the lateral bolt on the side where the guide bar of the housing is attached, the force in the direction twisting with respect to the crankshaft is effectively suppressed. can do.

  According to the invention of claim 8, there are two bolt holes respectively on one side and the other side perpendicular to the crankshaft of the crankcase, and a straight line passing through two bolts on one side and two on the other side. Bolt holes are formed so that straight lines passing through the bolts have different inclinations, and the engine is fixed to the housing by screwing the bolts into the bolt holes, so that one surface and the other as viewed from the axial direction of the crankshaft The force in the direction in which the engine rotates with respect to the housing can be reduced with the fixed portion of the surface of the surface by the bolt as a supporting point.

  According to invention of Claim 9, a crankcase is divided | segmented by a surface perpendicular | vertical to a crankshaft, and the perpendicular distance from two bolt holes on one side to a division surface is from two bolt holes on the other side. Since it is different from the vertical distance to the dividing plane, engine vibration in either direction can be effectively reduced.

  The above and other objects and novel features of the present invention will become apparent from the following description and drawings.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, parts having the same function are denoted by the same reference numerals, and repeated description is omitted. 1 is a perspective view showing an appearance of a chainsaw according to an embodiment of the present invention, FIG. 2 is a perspective view showing an appearance from another angle, FIG. 3 is a perspective view showing an appearance from another angle, and FIG. Is a front view, FIG. 5 is a rear view, and FIG. 6 is a bottom view.

  In FIG. 1, a chain saw 1 is mounted with a small engine such as a 2-cycle or 4-cycle engine, and a guide bar 11 protrudes in front of the main body. A saw chain (not shown) is wound around the periphery of the guide bar 11, and a tree, a branch, or the like can be cut by rotating the saw chain at a high speed. An engine described later is housed in the housing 2 in a horizontal position. The housing 2 not only houses the engine but also attaches a guide bar 11 and covers around the engine 2 and is a skeleton part of the chain saw 1. A main handle 3 is provided above the housing 2 so that the front handle 6 extends laterally and downward from the vicinity of the front end of the main handle.

  The main handle 3 is a handle for the operator to hold with the right hand, and the front handle 6 is a handle for the operator to hold with the left hand. A safety trigger 7a is provided near the upper portion of the main handle 3, and an ignition switch 7b is provided near the front end. A hand guard 12 is provided on the front side of the main handle. The hand guard 12 serves to protect a worker's hand from being hit by a branch or a cut object. Furthermore, the role of a brake for stopping the rotation of the saw chain by tilting the hand guard 12 forward may also be used. The left side of the housing 2 (hereinafter, this description will be described by defining front, rear, left and right as shown in FIG. 1 on the basis of when the operator holds the chainsaw 1) is covered with a left cover 4. A recoil starter (not shown) for starting the engine is accommodated inside the left cover 4, and a starter handle 13 is attached through the left cover 4. In front of the left cover 4, a fuel tank cap 14a and a chain oil tank cap 15a are provided.

  2, the guide bar 11 is fixed to the right side of the housing 2 by two bolts (not shown) extending from the housing 2 and nuts 17a and 17b. On the right side of the housing 2, a driving force transmission mechanism to a saw chain, which will be described later, is attached, and a light cover 5 is provided to cover it. A chain catcher 16 is provided in the vicinity of the attachment portion between the housing 2 and the guide bar 11.

  In FIG. 3, a muffler guard 8 provided with a mesh-shaped air vent on the most part of the surface is attached behind the light cover 5 in order to guard against the heat of the engine muffler 66. A rear cover 9 for covering an air cleaner described later is provided at the rear end of the chainsaw 1. The rear cover 9 is detachably fixed to the housing 2 by a fixing screw 18. On the right side of the fixing screw 18, a pull-out hook 20 is provided that is slidable back and forth. For example, when working on a tree, the hook 20 is used to hang a rope when the chainsaw 1 is pulled up to a high place with a rope. The state shown in FIG. 3 is a state in which the hook 20 is housed, and the hook 20 hardly protrudes to the outside of the rear cover 9 except for a necessary part to be pulled out by hand. For this reason, only the vicinity of the hook attachment portion of the rear cover 9 has a slightly recessed shape with respect to the surroundings, and the hook 20 can be prevented from hitting the operator's body or the surroundings during storage.

  FIG. 4 is a front view of the chainsaw 1 as seen from the front. The housing 2 is located substantially at the center in the left-right direction when viewed from the main body excluding the front handle 6. The housing 2 and the chain guard 11 are fixed by nuts 17a and 17b at a predetermined interval as shown in the figure. A sprocket, which will be described later, connected to the crankshaft of the engine via a centrifugal clutch 44 (FIG. 6) is provided behind the guide bar 11, and the saw chain is driven by rotating the sprocket.

  FIG. 5 is a rear view of the chainsaw 1 as seen from the rear. From this figure, the arrangement of the hooks 20 can be well understood. The hook 20 is preferably provided at a well-balanced position when the chain saw 1 is suspended using this. However, the attachment position of the hook 20 is relatively free, and if the chain saw 1 is well placed when suspended, for example, if the longitudinal direction of the guide bar 11 can be kept up and down, the chain saw 1 The main handle portion 3 may be provided behind or near the side. In order to attach the hook 20, the rear cover 9 is formed with a slit 9a. However, since the rear cover 9 is a slide-movable hook 20, the area required for the slit can be as small as the thickness of the hook. Further, the hook 20 may be interposed in the slit, so that dust or the like can be prevented from entering the cleaner cover 9. Further, since the hook 20 is directly fixed to the housing 2 instead of the rear cover 9 as will be described later, the chain saw 1 is suspended in a stable state without being affected even if the rear cover 9 is not completely installed. Can do.

  FIG. 6 is a bottom view of the chainsaw 1 as viewed from below. This figure shows a state in which the hook 20 is housed, but the point that the recess 9b is formed around the hook 20 and that the rear end surface of the hook 20 and the rear end portion of the rear cover 9 substantially coincide with each other. You can understand. Two bolts 33 and 34 are provided on the bottom surface of the housing 2. These bolts 33 and 34 are not located at the same position in the front-rear direction (longitudinal direction of the chain guard 11), and are provided with the bolt 33 offset to the right and the bolt 34 offset to the left as viewed in the drawing. The reason for this will be described later. The sprocket 43 is configured integrally with the rotor portion of the centrifugal clutch 44, and the rotation driving force of the engine 50 is transmitted to the saw chain when the saw chain is wound around the sprocket 43. A muffler 66 for silencing the exhaust sound of the engine 50 is provided on the rear side of the sprocket 43.

  Next, the internal structure of the chainsaw 1 will be described using the cross-sectional view shown in FIG. Inside the housing 2 of the chainsaw 1, the engine 50 is accommodated almost horizontally. Here, horizontal installation means that the direction of movement of the piston is horizontal during operation. Strictly speaking, in this embodiment, the direction of movement of the piston is not completely horizontal, and the tip portion is slightly lowered. It is “almost horizontal”. This is because when the engine 50 is completely placed horizontally, the height of the rear end portion of the chainsaw 1 is increased due to the relationship between the carburetor 67 and the air filter 68 disposed on the upper side thereof, and the engine 50 is inclined downward. It is what I did. In this embodiment, an example of a two-cycle engine is shown as the engine 50, but a four-cycle engine may be used. The engine 50 performs an intake-compression-combustion-exhaust stroke while a piston 62 attached to the crank 64 via a connecting rod 63 reciprocates. The engine 50 is fixed to the housing 2 by two bolts 31 (FIG. 8) and 32 from the upper side and two bolts 33 (FIG. 8) and 34 from the lower side. A fuel tank 14 for the engine 50 and a chain oil tank 15 for supplying oil to the saw chain are provided on the front side of the housing 2.

  FIG. 8 is a perspective view for explaining a mounting state of the housing 2 and the engine 50, and FIG. 9 is a perspective view from another angle. The housing 2 is configured by, for example, plastic integral molding, and the engine 50 is inserted in a direction indicated by an arrow in FIG. 8 and is fixed by four bolts 31 to 34 from the vertical direction. The engine 50 is formed with four screw holes (only 31b and 32b are shown in FIG. 8) to be screwed with these bolts. In FIG. 9, a flat surface portion 2a is formed on the front side of the surface opposite to the side where the engine is inserted of the housing 2 (the right surface), and two fixed to the housing 2 are formed outside the flat surface portion 2a. The guide bar 11 is attached to the bolts 19a and 19b, and is fixed by nuts 17a and 17b.

  In order to accommodate an oil pump (not shown), a recessed portion 2b that is recessed in a substantially rectangular shape is formed on the inner side when viewed from outside. By forming the recess 2b, the rigidity of the housing 2 can be further increased. A hole 2c for penetrating the crankshaft 51 is formed in the recess 2b. A hole 69a is formed on the side of the hole 2c, and is screwed into the screw hole 69 of the engine 50 from the lateral direction by the lateral bolt 41. . Here, in this embodiment, in addition to the four bolts 31 to 34 that are fixed from the vertical direction of the engine 50, the crankcase portion of the engine 50 is fixed by the lateral bolt 41 that is the fifth bolt. In addition, the engine 50 can be fixed to the housing 2 with good vibration characteristics.

  The recess 2b is covered with an oil pump cover 40 after an unillustrated oil pump is accommodated. The oil pump cover 40 is fixed to the housing 2 with three screws 42 through the crankshaft 51 through the hole 40a. Here, the screw 42 is screwed into a screw hole formed in the housing and does not contact the engine 50.

  FIG. 10 is a schematic diagram for explaining the effect of fixing the crankcase portion of the engine 50 by the lateral bolt 41. In the chain saw 1, when the engine 50 is driven to rotate the crankshaft 51 and the sprocket 43 is rotated through the centrifugal clutch, the saw chain 10 wound around the sprocket 43 and the guide bar 11 is rotated. This rotation cuts trees and branches. At this time, as a reaction force received from the saw chain 10, a force acts on the crankshaft 51 in the direction of the arrow 47, which becomes a force for moving the engine 50 in the direction of the arrow 48. When the force acts on the engine 50 in this way, it causes vibrations, and the housing 2 and the engine 50 flutter. In the present embodiment, the crankcase (53, 54) of the engine 50 is fixed in the direction parallel to the crankshaft by the lateral bolt 41 in consideration of the direction in which this force acts. Since the lateral bolt 41 is fixed to the recessed portion 2b of the housing 2, the engine side of the recessed portion 2b can be brought into good contact with the fixed portion of the crankcase (53, 54).

  The position where the lateral bolt 41 is provided is preferably fixed in a region between the crankshaft 51 and the bolt 19a in the front-rear direction. The vertical position of the horizontal bolt 41 is relatively free and should be arranged on the inner peripheral side of the flywheel 54 when viewed from the side. When compared with the winding range of the saw chain, the horizontal bolt 41 is positioned on the inner side. It may also be located outside. However, since the torque generated by the reaction force is large around the crankshaft 51, it should be relatively close to the crankshaft 51 and is particularly preferably inside the winding range of the saw chain. In this embodiment, the housing 2 is fixed at the position of the lateral bolt 41 because of the shape of the housing 2, but if possible, instead of the lateral bolt 41 or in addition to the bolt in the region 41b. It may be fixed. Further, the lateral bolt 41 may be fixed not only by a bolt but also by a nut or other known fixing means.

  In the present embodiment, the lateral bolt 41 is screwed into a fixing hole formed on the outer peripheral side of the right crankcase 52 of the crankcase. Even when viewed from the engine 50 side, it is fixed laterally on the outer peripheral side of the crankcase 52, so that the bolts 31 to 34 that are fixed vertically when viewed from above the chain saw 1 are attached to the rear side of the cylinder shaft 51. Since the lateral bolt 41 is fixed on the front side of the cylinder shaft 51, the engine 50 can be fixed to the housing 2 satisfactorily, and fluttering between the housing 2 and the engine 50 can be suppressed.

  FIG. 11 is a perspective view showing the arrangement of engine mounting holes in the housing 2. The upper two attachment holes 31 a and 32 a are not parallel to the axis of the crankshaft 51 when a straight line including these two points is drawn. Further, when the two lower mounting holes 33 a and 34 a draw a straight line including these two points, the straight line is not parallel to the axis of the crankshaft 51.

  Next, the engine 50 will be described with reference to FIGS. 12 is a perspective view of the engine 50 as seen from the upper left front side, and FIG. 13 is a perspective view of the engine 50 as seen from the lower left rear side. The crankcase is a split type composed of a right crankcase 52 and a left crankcase 53, and the split surface is a surface perpendicular to the axis of the crankshaft 51. A crankshaft 51 as an output shaft protrudes from the right crankcase 52, and a flywheel 54 is attached to the tip of the crankshaft from the left crankcase 52. The right crankcase 52 and the left crankcase 53 are fixed by three bolts 65a, 65b, 65c via a gasket (not shown) between them. In order to threadably engage with these three bolts 65a, 65b, 65c, the right crankcase 52 is formed with a female thread portion.

  Furthermore, the crankcase is provided with two bolt holes 31 b and 32 b for fixing the engine 50 to the housing 2 on the upper side of the engine 50. The bolt hole 31 b is provided in the left crankcase 53, and the bolt hole 32 b is provided in the right crankcase 52. Similarly, two bolt holes 33 b and 34 b are provided on the lower side of the engine 50. The bolt hole 33 b is provided in the left crankcase 53, and the bolt hole 34 b is provided in the right crankcase 52. Further, the right crankcase 52 is provided with a screw hole 69 screwed with the lateral bolt 41, and a female screw is formed on the inner peripheral side thereof.

  The flywheel 54 is configured integrally with the fins, and a permanent magnet for generating high voltage electricity for ignition by the ignition coil 59 is provided on a part of the outer peripheral side. A clutch pawl for connecting to the starter is provided on the inner peripheral side of the fin. The high-voltage electricity generated by the ignition coil 59 is transmitted to the plug cap 60 by a high-voltage cord extending from the ignition coil 59, and is supplied to the ignition plug 61 (FIG. 7) via the plug cap 60.

Here, the positional relationship between the bolt holes 31b, 32b, 33b, and 34b will be described in detail with reference to FIG. FIG. 14 (1) is an enlarged view when the crankcase portion of the engine 50 placed horizontally is viewed from above, and (2) is an enlarged view when the crankcase portion of the engine 50 is viewed from below. It is. In (1), the two bolt holes 31b and 32b for fixing from the upper side of the housing 2 are disposed at positions asymmetric with respect to the split surface of the crankcase as shown in the figure. Also, if minus the upper bolt connection line 71 is a straight line in this drawing through the two bolt holes 31b, the center point of 32b, having a tilt angle theta ₁ constant with respect to the axis 70 of the crankshaft. Similarly, in FIG. 14 (2), the two bolt holes 33b and 34b for fixing from the upper side of the housing 2 are arranged at positions asymmetric with respect to the split surface of the crankcase as shown in the figure. The Two bolt holes 33b, when minus the lower bolt connection line 72 is a straight line passing through the center point of 34b, it has a constant inclination angle theta ₂ with respect to the axis 70 of the crankshaft.

  FIG. 14 (3) is a diagram showing the arrangement of the four bolt holes when viewed from above the housing 2. Here, the lower bolt connecting line 72 seems to be opposite to the direction of inclination in FIG. 14 (2). This is because (2) is a view from the lower side of the housing 2, whereas (3 ) Is a diagram when projected from the upper side, and the arrangement of both is not changed. As can be understood from (3), the four bolt holes are located between the axis 70 and the dividing line 73 of the cylinder 55 and the crankcases 52 and 53 in the direction of movement of the piston of the engine. Further, when viewed in the lateral direction, that is, in the axial direction of the crankshaft 51, it is included in the range between the lines 74a and 74b, which is the width of the crankcase. Furthermore, the inclination of the straight lines of the connecting lines 71 and 72 is opposite, and when the connecting line 71 is extended, it crosses the axis line 70 on the flywheel 54 side outside the width of the crankcase.

  Similarly, when the connecting line 72 is extended, it crosses the axis line 70 on the guide bar 11 side outside the width of the crankcase. The distance from the split surface of the crankcase to the four bolts is L1 on the upper side and L2 on the lower side, and is different between the upper side and the lower side. Further, the distances from the axis 70 to the respective bolt holes 31b, 32b, 34b, 33b are different. Then, if the four bolts shown in FIG. 14 (3) are connected in the sequence of 31b → 32b → 34b → 33b → 31b, a rectangular area is formed.

  When the upper bolt connection line 71 and the lower bolt connection line 72 are configured to extend parallel to the axis 70, when the crankshaft 51 is driven, the upper and lower bolt connection lines 71 and 72 are viewed from the side where the guide bar 11 is provided. A force is likely to be applied in the direction in which the engine 50 rotates with respect to the housing 2 with the bolt fixed portion as a fulcrum. Further, when the upper bolt connecting line 71 and the lower bolt connecting line 72 are inclined at the same angle with respect to the axis 70, when viewed from the side where the guide bar 11 is provided when the crankshaft 51 is driven. Thus, although the force in the direction in which the engine 50 rotates with respect to the housing 2 with the fixed portions of the upper and lower bolts as fulcrums can be reduced as compared with the above configuration, the engine 50 when viewed from above. The force in the direction of rotating with respect to the housing 2 is easily applied.

  In the present invention, as described above, since at least one of the upper bolt connecting line 71 and the lower bolt connecting line 72 is inclined with respect to the axis 70, the upper side is viewed from the side where the guide bar is provided. In addition, the force in the direction in which the engine rotates with respect to the housing can be reduced with the fixing portion by the lower bolt as a fulcrum, and any one of the connecting lines (first lines) is relative to the axis 70 The connecting line on the side (lower side) located on the opposite side of the inclined side (upper side) has a different angle with respect to the first line, so that the engine 50 when viewed from above is in relation to the housing 2. Thus, the force in the rotating direction can be reduced.

  In the present embodiment, the upper bolt connecting line 71 and the lower bolt connecting line 72 are inclined in the opposite direction with respect to the axis 70, so that the engine when viewed from above is relative to the housing. Thus, the force in the rotating direction can be further reduced. In this embodiment, when the vibration characteristics were measured with such a bolt arrangement structure, good characteristics could be obtained in the chainsaw.

  As described above, a chain saw with good vibration characteristics can be realized by devising the position of the mounting bolt to the housing 2 of the engine 50. In this embodiment, the engine is fixed with bolts 31 to 34 having the same thickness and the same length. However, the bolts having different thicknesses and lengths are fixed according to the characteristics of the engine and the occurrence of vibration. You may make it do.

  Next, the detailed structure of the hook means will be described with reference to FIG. FIG. 15 (1) is a diagram showing a state in which the hook 20 is housed. The U-shaped member 35 constituting the hook means includes an upper arm 35a and a lower arm 35b extending in parallel from the housing 2, and It is comprised from the connection part 35c which bridges and connects a rear-end part. The U-shaped member 35 is configured to extend to the rear of the housing, and is preferably manufactured by integral molding with the housing 2. Screw holes 36a are formed in the upper arm 35a, and screw holes 36b and 36c are formed in the lower arm 35b. FIG. 15B is a diagram showing a state in which the hook 20 is pulled out, and the hook 20 is firmly connected to the housing 2 when the bent portion of the hook 20 is engaged with the connecting portion 35c. The position where the U-shaped member 35 is formed is most preferably provided in a well-balanced position when the chainsaw 1 is lifted by the hook 20 and is provided in the vicinity of the position of the center of gravity in a plane perpendicular to the front-rear direction.

  FIG. 15 (3) is a diagram showing the shape of the hook 20. The hook 20 is formed with a substantially circular ring portion 20e, a narrowed portion 20d is formed on the front side thereof, and the bent portion is bent upward as viewed in FIG. 15 (3) through two straight portions 20c. 20b is formed, and the horizontal portion 20a having a short distance is formed first from the bent portion 20. The hook 20 can be manufactured, for example, by bending a wire. At this time, the horizontal portion 20c may be formed so as to slightly open (the two straight portions are separated) as it goes in the direction of the bent portion 20b. If it does so, this hook 20 will exhibit a spring effect in the part of a circular ring | wheel, and has an effect which is urged | biased in the direction of the arrow in a figure. By attaching such a hook 20 to the U-shaped member 35, a force that presses the linear portion 20b of the hook 20 against the lower side of the upper arm portion 35a and the upper side of the lower arm portion 35b. When the hook 20 is stored, rattling or loosening due to the hook 20 can be effectively prevented. In addition, the linear part 20b can fulfill | perform the role of the stopper at the time of moving ahead (at the time of drawing in) by contact | abutting to a housing when it is pushed in.

  FIG. 16 is another perspective view showing the shape of the U-shaped member 35. Here, as can be understood from FIG. 16A, a groove 37 for guiding the straight portion 20c of the hook 20 is formed on the upper side of the lower arm portion 35b. Further, as shown in FIG. 16B, a recess 38 is formed on the right side surface of the upper arm portion 35a. In addition, the thickness of the center part of the connection part 35c in the left-right direction is thinner than the upper arm part 35a and the lower arm part 35b, and the space which accommodates the hook 20 at the time of pressing with the pressing plate 21 is ensured. Therefore, the right side surface of the connecting portion 35c has a lower shape than the right side surfaces of the upper arm portion 35a and the lower arm portion 35b, and has a step shape. Similarly, as can be understood from FIG. 16 (3), the left side surface of the connecting portion 35c and the vicinity of the central portion in the vertical direction have a shape 39b that is recessed from the left side surfaces of the upper arm portion 35a and the lower arm portion 35b. ing.

  FIG. 17 is a perspective view for explaining the hook 20 attached state. The hook 20 is installed between the upper and lower arms 35 a and 35 b of the U-shaped member, and the right side is fixed by the pressing plate 21. The holding plate 21 is fixed to the lower arm 35 b by two screws 22. A screw 24 passes through the upper hole of the holding plate 21 via the damper 23 and the mounting portion 3a of the main handle 3, and is fixed to the upper arm 35a. That is, the upper arm 35a also serves as a function of the attachment portion of the main handle 3. With such a configuration, the number of parts for attachment can be reduced and the cost can be reduced. Further, since the U-shaped member 35 is connected to the main handle 3, it is possible to realize a hook attachment portion that is strong in strength. Further, since the hook means is provided without using a hinge or a hinge, the hook means which is strong in strength can be realized.

  FIG. 18 is a perspective view showing a state after the hook 20 is attached, and shows a state where the muffler guard 8 is removed. In this figure, it will be understood that the attachment portion 3a on the rear end side of the main handle 3 is fixed by the hook attachment portion.

  FIG. 19 is a perspective view showing a state in which the hook 20 is pulled out. From this figure, it can be understood that the hook 20 is sufficiently pulled out from the rear cover 9 and the hanging rope is easily arranged.

  As mentioned above, although demonstrated based on embodiment which shows this invention, this invention is not limited to the above-mentioned form, A various change is possible within the range which does not deviate from the meaning. For example, in the present application, the chain saw has been described, but the present invention can be similarly applied to a portable tool using another small engine.

It is a perspective view which shows the external appearance of the chainsaw which concerns on embodiment of this invention. It is a perspective view which shows the external appearance from another angle of the chainsaw which concerns on embodiment of this invention. It is a perspective view which shows the external appearance from another angle of the chainsaw which concerns on embodiment of this invention. 1 is a front view of a chainsaw according to an embodiment of the present invention. It is a rear view of the chainsaw concerning an embodiment of the present invention. It is a bottom view of the chainsaw concerning an embodiment of the present invention. It is sectional drawing of the chainsaw which concerns on embodiment of this invention. It is a perspective view for demonstrating the attachment state of the chain saw housing 2 and the engine 50 which concerns on embodiment of this invention. It is a perspective view from another angle for demonstrating the attachment state of the housing 2 of the chainsaw which concerns on embodiment of this invention. FIG. 10 is a schematic diagram for explaining the effect of fixing the crankcase portion of the engine 50 by the lateral bolt 41 of FIG. 9. It is a perspective view which shows arrangement | positioning of the engine attachment hole of the housing 2 of the chainsaw which concerns on embodiment of this invention. It is a perspective view of the engine 50 of the chainsaw which concerns on embodiment of this invention. It is a perspective view from another angle of the engine 50 of the chainsaw which concerns on embodiment of this invention. The figure explaining the positional relationship of the bolt holes 31b, 32b, 33b, 34b which concern on embodiment of this invention, (1) is an enlarged view at the time of seeing the crankcase part of the engine 50 from the top, (2) is It is an enlarged view when the crankcase part is viewed from the lower side, and (3) is a projection view in which four bolt holes are projected from above the housing 2. It is a figure which shows the hook 20 of the chainsaw which concerns on embodiment of this invention, (1) shows the state which accommodated the hook 20, (2) shows the state which pulled out the hook 20. FIG. 6 is another perspective view showing the shape of the U-shaped member 35. FIG. It is a perspective view for demonstrating the attachment state of the hook 20 of the chainsaw which concerns on embodiment of this invention. It is a perspective view for demonstrating the state after attachment of the hook 20 of the chainsaw which concerns on embodiment of this invention. It is a perspective view which shows the state which pulled out the hook 20 of the chainsaw which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chain saw 2 Housing 3 Main handle 3a (Main handle's) attachment part 4 Left cover 5 Right cover 6 Front handle 7a Safety trigger 7b Ignition switch 8 Muffler guard 9 Rear cover 9a Slit 10 of the rear cover 13 Starter handle 14 Fuel tank 14a Cap 15 Chain oil tank 15a Cap 16 Chain catcher 17a, 17b Nut 18 Fixing screw 19a, 19b Bolt 20 Hook 21 Holding plate 22 Screw 23 Damper 24 Screw
31, 32, 33, 34 (For engine fixing) Bolts 31a, 32a, 33a, 34a (For engine fixing) Bolt holes 31b, 32b, 33b, 34b Screw hole 35 U-shaped member 35a Upper arm portion 35b Lower arm Part 35c connecting part 36 screw hole 37 groove 40 oil pump cover 40a (oil pump cover) hole 41 lateral bolt 42 (for oil pump cover fixing) screw 43 sprocket 44 centrifugal clutch 50 engine 51 crankshaft 52 right crankcase 53 left side Crankcase 54 Flywheel 55 Cylinder 56 Intake port 57 Exhaust port 59 Ignition coil unit 60 Plug cap 61 Spark plug 62 Piston 63 Connecting rod 64 Crank 65a, 65b, 65c Bolt 66 Muffler 67 Carburetor 68 Airflow Filter 69 Screw hole 70 (Crankshaft) axis 71 Upper bolt connection line 72 Lower bolt connection lines 74a, 74b Lines indicating the width of the crankcase

Claims (9)

A crankcase, a cylinder attached to the crankcase, an engine having a piston that reciprocates within the cylinder, a housing that houses the engine, and a guide bar attached to the housing, and wound around the guide bar by the engine In a chainsaw that rotates a saw chain that is turned,
The engine has two surfaces that are substantially parallel to the axial direction of the crankshaft covered by the housing, and is fixed by two bolts on each of the two surfaces.
When projected from one surface, the straight line passing through the two bolts on the one surface and the straight line passing through the two bolts on the other surface are inclined with respect to the crankshaft. And the bolts on the one surface and the other surface are arranged so that the straight line passing through the two bolts on the one surface and the straight line connecting the two bolts on the other surface are not parallel to each other. Chainsaw.   The chain saw according to claim 1, wherein a straight line passing through the two bolts on the one surface and a straight line passing through the two bolts on the opposite surface are inclined with respect to the crankshaft.   The chain saw according to claim 2, wherein the bolt is arranged to be tightened in a direction perpendicular to a moving direction of the piston.   4. The chainsaw according to claim 3, wherein the four bolts provided on the one surface and the other surface have different positions when projected from the one surface. 5.   When projected from the one surface, the inclination direction of the straight line passing through the two bolts on the one surface and the straight line passing through the two bolts on the other surface is different from the crankshaft. The chain saw according to claim 4.   The crankcase is divided by a plane perpendicular to the crankshaft, the two bolts on the one surface are attached to the divided crankcase one by one, and the two bolts on the other surface are divided by the division 6. The chain saw according to claim 5, wherein the chainsaw is attached to the crankcases one by one.   The chain saw according to claim 6, wherein the crankcase is fixed to the housing by a lateral bolt on a side of the housing where the guide bar is attached. A crankcase, a cylinder attached to the crankcase, an engine having a piston that reciprocates within the cylinder, a housing that houses the engine, and a guide bar attached to the housing, and wound around the guide bar by the engine In a chainsaw that rotates a saw chain that is turned,
Each of the crankcase has two bolt holes on one side and the other side perpendicular to the crankshaft,
The bolt hole is formed so that a straight line passing through the two bolts on the one side and a straight line passing through the two bolts on the other side have different inclinations, and the bolt is screwed into the bolt hole, thereby the engine. Is fixed to the housing. The crankcase is divided in a plane perpendicular to the crankshaft,
The vertical distance from the two bolt holes on the one side to the dividing surface is different from the vertical distance from the two bolt holes on the other side to the dividing surface. Chainsaw.

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