JP2013119189A - Portable cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve work efficiency of a portable cutter.SOLUTION: A rotary driven blade is provided to a cutter body, and cutting by the blade to a workpiece W to be cut is started by tilting the cutter body. When the blade reaches a desired cutting depth, the workpiece W is cut by advancing the cutting body. A wheel 32 is provided to the block member 33 of a lower part 30 of the cutter body, and the axle 37 of the wheel 32 is downward energized by a spring 40. Furthermore, a friction plate 41 facing the wheel 32 is provided to the block member 33. When the tilting of the cutter body is small, the spring 40 shrinks and the wheel 32 comes into contact with the friction plate 41, while when the tilting of the cutter body is large, the spring 40 elongates and the wheel 32 is separated from the friction plate 41. Thereby, when providing the cutter body on the cutting object material W, the wheel 32 can be fixed, and when the cutter body is advanced to cut the workpiece W, the wheel 32 can be rotated.

Description

  The present invention relates to a portable cutting machine including a blade that is rotationally driven by a driving source.

  An engine cutter or the like is a portable cutting machine for performing creasing and cutting operations on concrete, asphalt, stone, and the like. A portable cutting machine, also called a hand-held cutting machine, has a cutting machine body on which an engine as a drive source is mounted, and a blade that is rotationally driven by the engine is provided on the front side of the cutting machine body, A rear handle that is grasped by an operator is provided on the rear side of the cutting machine main body. In addition, a foot member that comes into contact with a material to be cut such as concrete is provided at the lower portion of the cutting machine main body (see, for example, Patent Document 1). For example, when cutting concrete, after installing an engine cutter on the concrete and starting the engine, the operator pulls the rear handle upward. As a result, the engine cutter is inclined with the foot member in contact with the concrete as a fulcrum, so that the rotating blade is lowered and the cutting into the concrete is started. Then, after pulling up the rear handle until the desired depth of cut is reached, the portable cutting machine is pushed forward while sliding the foot member, thereby cutting the concrete while moving the portable cutting machine forward. It is like that.

Japanese Patent No. 2998418

  By the way, in the portable cutting machine provided with the foot member at the lower part of the cutting machine main body like the portable cutting machine described in Patent Document 1, it is necessary to slide the foot member on the material to be cut during the cutting operation. For this reason, it has been difficult to push the portable cutting machine forward. In order to facilitate such cutting work and improve the workability of the portable cutting machine, it is possible to form the foot member with a material having a small friction coefficient, but the foot member in contact with the material to be cut is formed to be slippery. This causes unintended movement of the portable cutting machine on the inclined surface and unintentional movement of the portable cutting machine due to engine vibration. Such unintended movement of the portable cutting machine has been a factor that reduces the workability of the portable cutting machine.

  An object of the present invention is to improve the workability of a portable cutting machine.

  The portable cutting machine of the present invention is a portable cutting machine that has a cutting machine main body including a blade that is rotationally driven by a drive source, and cuts a material to be cut using the blade. It has a wheel provided in a lower part, and a lock mechanism which controls rotation of the wheel.

  The portable cutting machine according to the present invention is characterized in that the lock mechanism is switched to a locked state in which rotation of the wheel is restricted by a load acting on the wheel from the cutting machine body. The portable cutting machine of the present invention is characterized in that the lock mechanism is switched to a release state in which the rotation restriction of the wheel is released by tilting the cutting machine body with the wheel as a fulcrum.

  According to the present invention, the wheel is provided at the lower portion of the cutting machine main body and the lock mechanism for restricting the rotation of the wheel is provided. By this, when installing the cutting machine body on the material to be cut or when tilting the cutting machine body and cutting the blade into the material to be cut, the rotation of the wheel is regulated by the lock mechanism, so that the portable cutting Unnecessary movement of the machine can be prevented, and the workability of the portable cutting machine can be improved.

It is a side view which shows the engine cutter as a portable cutting machine which is one embodiment of this invention. (a) is the elements on larger scale which show the range (alpha) of FIG. 1, (b) is a fragmentary sectional view which shows the structure of an engine cutter along the AA line of FIG. 2 (a). It is explanatory drawing which shows the cutting | disconnection procedure by an engine cutter. It is explanatory drawing which shows the cutting | disconnection procedure by an engine cutter. (a)-(c) is the elements on larger scale which show the operation state of the wheel at the time of cutting work, (d)-(f) is a fragmentary sectional view which shows the operation state of the wheel at the time of cutting work. (a) And (b) is explanatory drawing which shows the force which acts on an axle. (a) And (b) is the elements on larger scale which show the other operation state of a wheel, (c) And (d) is a fragmentary sectional view which shows the other operation state of a wheel.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view showing an engine cutter 10 as a portable cutting machine according to an embodiment of the present invention. As shown in FIG. 1, the engine cutter 10 has a cutting machine body 11, and an engine 12 that is a drive source is mounted on the cutting machine body 11. A power transmission arm 13 is attached to a crankcase (not shown) of the engine 12, and a disk-shaped blade 14 is attached to the tip of the power transmission arm 13. Thus, the blade 14 is provided on one end side of the cutting machine body 11. Further, the power transmission arm 13 is assembled with an output shaft 15 connected to a crankshaft (not shown) via a centrifugal clutch, and a rotating shaft 16 fixed to the center portion of the blade 14. A driving pulley 17 is fixed to the output shaft 15, and a driven pulley 18 is fixed to the rotating shaft 16. Further, a belt 19 is wound around the driving pulley 17 and the driven pulley 18, and engine power is transmitted to the blade 14 via the belt 19. The power transmission arm 13 is provided with a blade cover 20 that partially covers the blade 14.

  The cutting machine main body 11 is provided with a front handle 21 held by one hand of the operator, and the front handle 21 is attached so as to straddle the cutting machine main body 11 from above. A rear handle 22 is provided at the rear end of the cutting machine main body 11 and is gripped by the operator's other hand. Further, the rear handle 22 is provided with a throttle lever 23 for adjusting the engine speed, and a lock lever 24 for releasing the operation restriction of the throttle lever 23.

  A rear foot 31 that supports the rear portion of the cutting machine body 11 is provided in the lower portion 30 on the rear side of the cutting machine body 11. Further, a wheel 32 that supports the front portion of the cutting machine body 11 is provided in the lower portion 30 on the front side of the cutting machine body 11. Here, FIG. 2A is a partially enlarged view showing the range α in FIG. 1, and FIG. 2B is a partial cross-sectional view showing the structure of the engine cutter 10 along the line AA in FIG. FIG. As shown in FIGS. 2A and 2B, the block member 33 constituting the lower portion 30 of the cutting machine body 11 is provided with a pair of wheel accommodating portions 34 extending downward. Each wheel accommodating portion 34 is composed of a pair of stays 35, and each stay 35 is formed with a substantially U-shaped guide hole 36. A wheel 32 is rotatably accommodated in the wheel accommodating portion 34, and an axle 37 accommodated in the guide hole 36 is fixed to each wheel 32. Further, a spring receiver 38 is fixed to the central portion of the block member 33, and a spring receiver 39 is rotatably attached to the central portion of the axle 37. A spring 40 is assembled between the spring receivers 38 and 39, and the axle 37 is biased downward by the spring force of the spring 40. As shown in FIG. 2A, when the cutting machine main body 11 is installed on a horizontal workpiece W, the spring 40 is arranged substantially along the vertical direction. That is, in the case shown in the drawing, the axle 37 is urged substantially in the vertical direction by the spring force of the spring 40.

  As described above, the guide hole 36 in which the axle 37 is accommodated is formed in a substantially U shape, and the axle 37 can be moved to four positions in the guide hole 36. That is, as shown by a solid line and an alternate long and short dash line in FIG. 2A, the axle 37 is moved to two lock positions indicated by reference characters Pa1 and Pb1 and two release positions indicated by reference characters Pa2 and Pb2. Is possible. Here, a plate-like friction plate 41 is assembled in the wheel housing portion 34, and the friction plate 41 is installed so as to face the outer peripheral surface of the wheel 32. Therefore, the wheel 32 can be pressed against the friction plate 41 by contracting the spring 40 and moving the axle 37 to the upper locking positions Pa1 and Pb1, and the rotation of the wheel 32 is regulated by the friction plate 41. Is possible. On the other hand, by extending the spring 40 and moving the axle 37 to the lower release positions Pa2, Pb2, the wheel 32 can be released from being pressed against the friction plate 41, and the rotation restriction of the wheel 32 by the friction plate 41 is released. It becomes possible to do. As described above, the friction plate 41, the axle 37, the guide hole 36, and the spring 40 constitute a lock mechanism 42 that restricts the rotation of the wheel 32. The lock mechanism 42 is switched to the locked state by moving the axle 37 to the lock positions Pa1, Pb1, while the lock mechanism 42 is switched to the released state by moving the axle 37 to the release positions Pa2, Pb2. .

  Next, a procedure for cutting the workpiece W using the engine cutter 10 will be described. Here, FIGS. 3 and 4 are explanatory views showing a cutting procedure by the engine cutter 10. FIGS. 5A to 5C are partial enlarged views showing the operating state of the wheel 32 during the cutting operation, and FIGS. 5D to 5F show the operating state of the wheel 32 during the cutting operation. It is a fragmentary sectional view. 5 (a) shows the range α in FIG. 1, FIG. 5 (b) shows the range α in FIG. 3, and FIG. 5 (c) shows the range α in FIG. Yes. 5 (d) shows a cross section along the line AA in FIG. 5 (a), and FIG. 5 (e) shows a cross section along the line AA in FIG. 5 (b). FIG. 5 (f) shows a cross section taken along line AA in FIG. 5 (c).

  First, as shown in FIG. 1, when cutting a material to be cut W such as concrete, asphalt, or stone, a cutting machine main body 11 (engine cutter 10) is installed on the material to be cut W. At this time, as shown in FIGS. 5A and 5D, the load from the cutting machine body 11 acts on the wheel 32 in contact with the workpiece W, so that the axle 37 is locked while compressing the spring 40. It will be in the state moved to position Pa1. Thus, when the cutting machine main body 11 is installed on the workpiece W, the rotation of the wheel 32 is regulated by the lock mechanism 42, and thus the workpiece W is inclined. Also, unnecessary movement of the cutting machine body 11 can be prevented. Further, since the rotation of the wheel 32 is restricted even when the engine 12 is operated in an idling state with the cutting machine main body 11 installed on the workpiece W, the engine It is possible to prevent unnecessary movement of the cutting machine main body 11 due to vibration.

  Subsequently, the operator grasps the front handle 21 and the rear handle 22 and operates the throttle lever 23 to rotate the blade 14 while moving the rear part of the cutting machine body 11 upward as indicated by an arrow A in FIG. Pull up. Thereby, as shown in FIG. 3 and FIG. 5B, the cutting machine body 11 is tilted with the wheel 32 as a fulcrum, and the blade 14 starts to cut into the workpiece W. Then, as indicated by an arrow A in FIG. 4, the rear portion of the cutting machine body 11 is pulled upward until the blade 14 reaches a desired cutting depth. Thereafter, the operator operates to push the cutting machine main body 11 forward as indicated by an arrow B in FIG. 4 while holding the front handle 21 and the rear handle 22. Thereby, the cutting machine body 11 can be moved forward, and the workpiece W can be cut by the blade 14.

  Here, as shown in FIGS. 5 (b) and 5 (e), when the cutting by the blade 14 is started, the spring 40 is compressed because the inclination angle of the cutting machine body 11 with respect to the workpiece W is small. In this state, the axle 37 remains in the lock position Pa1. On the other hand, as shown in FIGS. 5C and 5F, when the cutting by the blade 14 is advanced, the inclination angle of the cutting machine main body 11 with respect to the material W to be cut increases, so that the spring force of the spring 40 is increased. As a result, the axle 37 is moved to the release position Pa2. Here, FIGS. 6A and 6B are explanatory views showing the force acting on the axle 37. FIG. FIG. 6A shows a state when the inclination angle X of the cutting machine body 11 is small, and FIG. 6B shows a state when the inclination angle X of the cutting machine body 11 is large. As shown in FIG. 6A, a spring force Fs from the spring 40 acts on the axle 37 and a reaction force Fa from the material W to be cut due to the weight of the cutting machine body 11 acts. Further, symbol Fa1 indicates a component force of the reaction force Fa facing the spring force Fs, and symbol Fa2 indicates a component force of the reaction force Fa orthogonal to the component force Fa1. As shown in FIGS. 6A and 6B, each time the inclination angle X of the cutting machine body 11 increases, the component force Fa1 that opposes the spring force Fs decreases. Therefore, when the cutting of the blade 14 with respect to the workpiece W progresses, the spring force Fs exceeds the component force Fa1 that acts on the axle 37, so that the axle 37 moves from the lock position Pa1 to the release position Pa2 by the spring force Fs. Become.

  That is, as shown in FIGS. 5B and 5E, when the cutting by the blade 14 is started, the rotation of the wheel 32 is restricted by the lock mechanism 42 that is in the locked state. The blade 14 can be lowered to a position aimed by the operator without swinging the left and right 11. Thus, since the blade 14 can be cut easily and reliably, the workability of the engine cutter 10 can be improved. Further, as shown in FIGS. 5C and 5F, at the stage where the cutting by the blade 14 has advanced, the rotation restriction of the wheel 32 is released by the lock mechanism 42 that is in the released state. The cutter main body 11 can be advanced with a small force while rotating. Thus, since the cutting machine main body 11 can be easily advanced during cutting, the workability of the engine cutter 10 can be improved. As shown in FIGS. 5C and 6B, when the axle 37 is moved to the release position Pa2, the axle 37 is pressed against the wall surface 36a of the guide hole 36. If the inclined state of the cutting machine main body 11 is maintained, the axle shaft 37 will not return to the lock position Pa1.

  7A and 7B are partially enlarged views showing other operating states of the wheel 32, and FIGS. 7C and 7D are partial cross-sectional views showing other operating states of the wheel 32. FIG. It is. 7C shows a cross section along the line AA in FIG. 7A, and FIG. 7D shows a cross section along the line AA in FIG. 7B. Has been. In the above description, the axle 37 is moved to the lock position Pa1 and the release position Pa2 according to the inclination angle of the cutting machine main body 11 by arranging the axle 37 on the rear side of the guide hole 36. There is no limit. That is, as shown in FIGS. 7 (a) and 7 (c), the axle 37 may be arranged at the lock position Pb1 on the front side of the guide hole 36. As shown in FIGS. 7 (b) and (d), The axle 37 may be disposed at the release position Pb2 on the front side of the guide hole 36. Since the partition wall 36b is provided between the lock position Pb1 and the release position Pb2, the lock mechanism 42 is held in the locked state regardless of the inclination of the cutting machine body 11 by disposing the axle 37 at the lock position Pb1. Is possible. On the other hand, by disposing the axle 37 at the release position Pb2, the lock mechanism 42 can be held in the release state regardless of the inclination of the cutting machine body 11.

  As shown in FIGS. 3 and 4, in the above description, after the cutting machine body 11 is tilted until the cutting of the workpiece W is started, the axle 37 is moved from the lock position Pa1 to the release position Pa2. However, it is not limited to this. For example, the shape of the guide hole 36 and the spring force of the spring 40 may be adjusted so that the axle 37 is moved from the lock position Pa1 to the release position Pa2 before the blade 14 contacts the workpiece W. . Further, in the above description, the lock position Pa1 and the release position Pa2 are provided on the rear side of the guide hole 36, and the lock position Pb1 and the release position Pb2 are provided on the front side of the guide hole 36. Instead, the shape of the guide hole 36 shown in FIG. 2A may be reversed front and back (left and right in FIG. 2). That is, the lock position Pb1 and the release position Pb2 may be provided on the rear side of the guide hole 36, and the lock position Pa1 and the release position Pa2 may be provided on the front side of the guide hole 36.

  In the above description, the lock mechanism 42 is switched between the locked state and the released state by moving the axle 37 in the guide hole 36 in accordance with the inclination angle of the cutting machine body 11. It is not limited to the structure. For example, the lock mechanism may be configured by a band brake, a drum brake, a disc brake, or the like. When the lock mechanism is configured by a band brake or the like, the operation state of the lock mechanism may be switched in conjunction with a manually operated lever, or the operation state of the lock mechanism is switched in conjunction with the throttle lever 23. May be. For example, when the lock mechanism is operated in conjunction with the throttle lever 23, the lock mechanism is switched to the locked state when the throttle lever 23 is not operated, while the lock mechanism is operated when the throttle lever 23 is operated. Switched to the released state. As described above, the workability of the engine cutter 10 can be improved by operating the lock mechanism in conjunction with the throttle lever 23.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the illustrated case, the engine 12 is used as a drive source, but the present invention is not limited to this, and an electric motor may be used as the drive source. The engine 12 may be a 4-stroke engine or a 2-stroke engine.

DESCRIPTION OF SYMBOLS 10 ... Engine cutter (portable cutting machine), 11 ... Cutting machine main body, 12 ... Engine (drive source), 13 ... Power transmission arm, 14 ... Blade, 15 ... Output shaft, 16 ... Rotating shaft, 17 ... Drive pulley, 18 ... driven pulley, 19 ... belt, 20 ... blade cover, 21 ... front handle, 22 ... rear handle, 23 ... throttle lever, 24 ... lock lever, 30 ... lower part, 31 ... rear foot, 32 ... wheel, 33 ... block member , 34 ... Wheel housing part, 35 ... Stay, 36 ... Guide hole, 36a ... Wall surface, 36b ... Bulkhead, 37 ... Axle, 38 ... Spring receiver, 39 ... Spring receiver, 40 ... Spring, 41 ... Friction plate, 42 ... Lock Mechanism, W ... Material to be cut

Claims (3)

A portable cutting machine having a cutting machine body provided with a blade driven to rotate by a driving source, and cutting a material to be cut using the blade,
Wheels provided at the lower part of the cutting machine body;
A portable cutting machine having a lock mechanism for restricting rotation of the wheel.   The portable cutting machine according to claim 1, wherein the locking mechanism is switched to a locked state that restricts rotation of the wheel by a load acting on the wheel from the cutting machine body.   3. The portable cutting machine according to claim 1, wherein the lock mechanism is switched to a release state in which the rotation restriction of the wheel is released by tilting the cutting machine body with the wheel as a fulcrum. 4.

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